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-rw-r--r--net/mptcp/Kconfig39
-rw-r--r--net/mptcp/Makefile12
-rw-r--r--net/mptcp/crypto.c83
-rw-r--r--net/mptcp/crypto_test.c72
-rw-r--r--net/mptcp/ctrl.c131
-rw-r--r--net/mptcp/diag.c104
-rw-r--r--net/mptcp/mib.c79
-rw-r--r--net/mptcp/mib.h49
-rw-r--r--net/mptcp/mptcp_diag.c169
-rw-r--r--net/mptcp/options.c1138
-rw-r--r--net/mptcp/pm.c252
-rw-r--r--net/mptcp/pm_netlink.c1139
-rw-r--r--net/mptcp/protocol.c2893
-rw-r--r--net/mptcp/protocol.h568
-rw-r--r--net/mptcp/subflow.c1469
-rw-r--r--net/mptcp/syncookies.c133
-rw-r--r--net/mptcp/token.c416
-rw-r--r--net/mptcp/token_test.c142
18 files changed, 8888 insertions, 0 deletions
diff --git a/net/mptcp/Kconfig b/net/mptcp/Kconfig
new file mode 100644
index 000000000..a014149aa
--- /dev/null
+++ b/net/mptcp/Kconfig
@@ -0,0 +1,39 @@
+
+config MPTCP
+ bool "MPTCP: Multipath TCP"
+ depends on INET
+ select SKB_EXTENSIONS
+ select CRYPTO_LIB_SHA256
+ select CRYPTO
+ help
+ Multipath TCP (MPTCP) connections send and receive data over multiple
+ subflows in order to utilize multiple network paths. Each subflow
+ uses the TCP protocol, and TCP options carry header information for
+ MPTCP.
+
+if MPTCP
+
+config INET_MPTCP_DIAG
+ depends on INET_DIAG
+ def_tristate INET_DIAG
+
+config MPTCP_IPV6
+ bool "MPTCP: IPv6 support for Multipath TCP"
+ depends on IPV6=y
+ default y
+
+config MPTCP_KUNIT_TESTS
+ tristate "This builds the MPTCP KUnit tests" if !KUNIT_ALL_TESTS
+ depends on KUNIT
+ default KUNIT_ALL_TESTS
+ help
+ Currently covers the MPTCP crypto and token helpers.
+ Only useful for kernel devs running KUnit test harness and are not
+ for inclusion into a production build.
+
+ For more information on KUnit and unit tests in general please refer
+ to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+ If unsure, say N.
+
+endif
diff --git a/net/mptcp/Makefile b/net/mptcp/Makefile
new file mode 100644
index 000000000..a611968be
--- /dev/null
+++ b/net/mptcp/Makefile
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_MPTCP) += mptcp.o
+
+mptcp-y := protocol.o subflow.o options.o token.o crypto.o ctrl.o pm.o diag.o \
+ mib.o pm_netlink.o
+
+obj-$(CONFIG_SYN_COOKIES) += syncookies.o
+obj-$(CONFIG_INET_MPTCP_DIAG) += mptcp_diag.o
+
+mptcp_crypto_test-objs := crypto_test.o
+mptcp_token_test-objs := token_test.o
+obj-$(CONFIG_MPTCP_KUNIT_TESTS) += mptcp_crypto_test.o mptcp_token_test.o
diff --git a/net/mptcp/crypto.c b/net/mptcp/crypto.c
new file mode 100644
index 000000000..05d398d3f
--- /dev/null
+++ b/net/mptcp/crypto.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP cryptographic functions
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ *
+ * Note: This code is based on mptcp_ctrl.c, mptcp_ipv4.c, and
+ * mptcp_ipv6 from multipath-tcp.org, authored by:
+ *
+ * Sébastien Barré <sebastien.barre@uclouvain.be>
+ * Christoph Paasch <christoph.paasch@uclouvain.be>
+ * Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ * Gregory Detal <gregory.detal@uclouvain.be>
+ * Fabien Duchêne <fabien.duchene@uclouvain.be>
+ * Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ * Lavkesh Lahngir <lavkesh51@gmail.com>
+ * Andreas Ripke <ripke@neclab.eu>
+ * Vlad Dogaru <vlad.dogaru@intel.com>
+ * Octavian Purdila <octavian.purdila@intel.com>
+ * John Ronan <jronan@tssg.org>
+ * Catalin Nicutar <catalin.nicutar@gmail.com>
+ * Brandon Heller <brandonh@stanford.edu>
+ */
+
+#include <linux/kernel.h>
+#include <crypto/sha.h>
+#include <asm/unaligned.h>
+
+#include "protocol.h"
+
+#define SHA256_DIGEST_WORDS (SHA256_DIGEST_SIZE / 4)
+
+void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn)
+{
+ __be32 mptcp_hashed_key[SHA256_DIGEST_WORDS];
+ __be64 input = cpu_to_be64(key);
+
+ sha256((__force u8 *)&input, sizeof(input), (u8 *)mptcp_hashed_key);
+
+ if (token)
+ *token = be32_to_cpu(mptcp_hashed_key[0]);
+ if (idsn)
+ *idsn = be64_to_cpu(*((__be64 *)&mptcp_hashed_key[6]));
+}
+
+void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac)
+{
+ u8 input[SHA256_BLOCK_SIZE + SHA256_DIGEST_SIZE];
+ u8 key1be[8];
+ u8 key2be[8];
+ int i;
+
+ if (WARN_ON_ONCE(len > SHA256_DIGEST_SIZE))
+ len = SHA256_DIGEST_SIZE;
+
+ put_unaligned_be64(key1, key1be);
+ put_unaligned_be64(key2, key2be);
+
+ /* Generate key xored with ipad */
+ memset(input, 0x36, SHA256_BLOCK_SIZE);
+ for (i = 0; i < 8; i++)
+ input[i] ^= key1be[i];
+ for (i = 0; i < 8; i++)
+ input[i + 8] ^= key2be[i];
+
+ memcpy(&input[SHA256_BLOCK_SIZE], msg, len);
+
+ /* emit sha256(K1 || msg) on the second input block, so we can
+ * reuse 'input' for the last hashing
+ */
+ sha256(input, SHA256_BLOCK_SIZE + len, &input[SHA256_BLOCK_SIZE]);
+
+ /* Prepare second part of hmac */
+ memset(input, 0x5C, SHA256_BLOCK_SIZE);
+ for (i = 0; i < 8; i++)
+ input[i] ^= key1be[i];
+ for (i = 0; i < 8; i++)
+ input[i + 8] ^= key2be[i];
+
+ sha256(input, SHA256_BLOCK_SIZE + SHA256_DIGEST_SIZE, hmac);
+}
+
+#if IS_MODULE(CONFIG_MPTCP_KUNIT_TESTS)
+EXPORT_SYMBOL_GPL(mptcp_crypto_hmac_sha);
+#endif
diff --git a/net/mptcp/crypto_test.c b/net/mptcp/crypto_test.c
new file mode 100644
index 000000000..017248dea
--- /dev/null
+++ b/net/mptcp/crypto_test.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <kunit/test.h>
+
+#include "protocol.h"
+
+struct test_case {
+ char *key;
+ char *msg;
+ char *result;
+};
+
+/* we can't reuse RFC 4231 test vectors, as we have constraint on the
+ * input and key size.
+ */
+static struct test_case tests[] = {
+ {
+ .key = "0b0b0b0b0b0b0b0b",
+ .msg = "48692054",
+ .result = "8385e24fb4235ac37556b6b886db106284a1da671699f46db1f235ec622dcafa",
+ },
+ {
+ .key = "aaaaaaaaaaaaaaaa",
+ .msg = "dddddddd",
+ .result = "2c5e219164ff1dca1c4a92318d847bb6b9d44492984e1eb71aff9022f71046e9",
+ },
+ {
+ .key = "0102030405060708",
+ .msg = "cdcdcdcd",
+ .result = "e73b9ba9969969cefb04aa0d6df18ec2fcc075b6f23b4d8c4da736a5dbbc6e7d",
+ },
+};
+
+static void mptcp_crypto_test_basic(struct kunit *test)
+{
+ char hmac[32], hmac_hex[65];
+ u32 nonce1, nonce2;
+ u64 key1, key2;
+ u8 msg[8];
+ int i, j;
+
+ for (i = 0; i < ARRAY_SIZE(tests); ++i) {
+ /* mptcp hmap will convert to be before computing the hmac */
+ key1 = be64_to_cpu(*((__be64 *)&tests[i].key[0]));
+ key2 = be64_to_cpu(*((__be64 *)&tests[i].key[8]));
+ nonce1 = be32_to_cpu(*((__be32 *)&tests[i].msg[0]));
+ nonce2 = be32_to_cpu(*((__be32 *)&tests[i].msg[4]));
+
+ put_unaligned_be32(nonce1, &msg[0]);
+ put_unaligned_be32(nonce2, &msg[4]);
+
+ mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac);
+ for (j = 0; j < 32; ++j)
+ sprintf(&hmac_hex[j << 1], "%02x", hmac[j] & 0xff);
+ hmac_hex[64] = 0;
+
+ KUNIT_EXPECT_STREQ(test, &hmac_hex[0], tests[i].result);
+ }
+}
+
+static struct kunit_case mptcp_crypto_test_cases[] = {
+ KUNIT_CASE(mptcp_crypto_test_basic),
+ {}
+};
+
+static struct kunit_suite mptcp_crypto_suite = {
+ .name = "mptcp-crypto",
+ .test_cases = mptcp_crypto_test_cases,
+};
+
+kunit_test_suite(mptcp_crypto_suite);
+
+MODULE_LICENSE("GPL");
diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c
new file mode 100644
index 000000000..54b888f94
--- /dev/null
+++ b/net/mptcp/ctrl.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2019, Tessares SA.
+ */
+
+#include <linux/sysctl.h>
+
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
+#include "protocol.h"
+
+#define MPTCP_SYSCTL_PATH "net/mptcp"
+
+static int mptcp_pernet_id;
+struct mptcp_pernet {
+ struct ctl_table_header *ctl_table_hdr;
+
+ int mptcp_enabled;
+};
+
+static struct mptcp_pernet *mptcp_get_pernet(struct net *net)
+{
+ return net_generic(net, mptcp_pernet_id);
+}
+
+int mptcp_is_enabled(struct net *net)
+{
+ return mptcp_get_pernet(net)->mptcp_enabled;
+}
+
+static struct ctl_table mptcp_sysctl_table[] = {
+ {
+ .procname = "enabled",
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ /* users with CAP_NET_ADMIN or root (not and) can change this
+ * value, same as other sysctl or the 'net' tree.
+ */
+ .proc_handler = proc_dointvec,
+ },
+ {}
+};
+
+static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet)
+{
+ pernet->mptcp_enabled = 1;
+}
+
+static int mptcp_pernet_new_table(struct net *net, struct mptcp_pernet *pernet)
+{
+ struct ctl_table_header *hdr;
+ struct ctl_table *table;
+
+ table = mptcp_sysctl_table;
+ if (!net_eq(net, &init_net)) {
+ table = kmemdup(table, sizeof(mptcp_sysctl_table), GFP_KERNEL);
+ if (!table)
+ goto err_alloc;
+ }
+
+ table[0].data = &pernet->mptcp_enabled;
+
+ hdr = register_net_sysctl(net, MPTCP_SYSCTL_PATH, table);
+ if (!hdr)
+ goto err_reg;
+
+ pernet->ctl_table_hdr = hdr;
+
+ return 0;
+
+err_reg:
+ if (!net_eq(net, &init_net))
+ kfree(table);
+err_alloc:
+ return -ENOMEM;
+}
+
+static void mptcp_pernet_del_table(struct mptcp_pernet *pernet)
+{
+ struct ctl_table *table = pernet->ctl_table_hdr->ctl_table_arg;
+
+ unregister_net_sysctl_table(pernet->ctl_table_hdr);
+
+ kfree(table);
+}
+
+static int __net_init mptcp_net_init(struct net *net)
+{
+ struct mptcp_pernet *pernet = mptcp_get_pernet(net);
+
+ mptcp_pernet_set_defaults(pernet);
+
+ return mptcp_pernet_new_table(net, pernet);
+}
+
+/* Note: the callback will only be called per extra netns */
+static void __net_exit mptcp_net_exit(struct net *net)
+{
+ struct mptcp_pernet *pernet = mptcp_get_pernet(net);
+
+ mptcp_pernet_del_table(pernet);
+}
+
+static struct pernet_operations mptcp_pernet_ops = {
+ .init = mptcp_net_init,
+ .exit = mptcp_net_exit,
+ .id = &mptcp_pernet_id,
+ .size = sizeof(struct mptcp_pernet),
+};
+
+void __init mptcp_init(void)
+{
+ mptcp_join_cookie_init();
+ mptcp_proto_init();
+
+ if (register_pernet_subsys(&mptcp_pernet_ops) < 0)
+ panic("Failed to register MPTCP pernet subsystem.\n");
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+int __init mptcpv6_init(void)
+{
+ int err;
+
+ err = mptcp_proto_v6_init();
+
+ return err;
+}
+#endif
diff --git a/net/mptcp/diag.c b/net/mptcp/diag.c
new file mode 100644
index 000000000..a53658674
--- /dev/null
+++ b/net/mptcp/diag.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+/* MPTCP socket monitoring support
+ *
+ * Copyright (c) 2019 Red Hat
+ *
+ * Author: Davide Caratti <dcaratti@redhat.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/net.h>
+#include <linux/inet_diag.h>
+#include <net/netlink.h>
+#include <uapi/linux/mptcp.h>
+#include "protocol.h"
+
+static int subflow_get_info(const struct sock *sk, struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *sf;
+ struct nlattr *start;
+ u32 flags = 0;
+ int err;
+
+ start = nla_nest_start_noflag(skb, INET_ULP_INFO_MPTCP);
+ if (!start)
+ return -EMSGSIZE;
+
+ rcu_read_lock();
+ sf = rcu_dereference(inet_csk(sk)->icsk_ulp_data);
+ if (!sf) {
+ err = 0;
+ goto nla_failure;
+ }
+
+ if (sf->mp_capable)
+ flags |= MPTCP_SUBFLOW_FLAG_MCAP_REM;
+ if (sf->request_mptcp)
+ flags |= MPTCP_SUBFLOW_FLAG_MCAP_LOC;
+ if (sf->mp_join)
+ flags |= MPTCP_SUBFLOW_FLAG_JOIN_REM;
+ if (sf->request_join)
+ flags |= MPTCP_SUBFLOW_FLAG_JOIN_LOC;
+ if (sf->backup)
+ flags |= MPTCP_SUBFLOW_FLAG_BKUP_REM;
+ if (sf->request_bkup)
+ flags |= MPTCP_SUBFLOW_FLAG_BKUP_LOC;
+ if (sf->fully_established)
+ flags |= MPTCP_SUBFLOW_FLAG_FULLY_ESTABLISHED;
+ if (sf->conn_finished)
+ flags |= MPTCP_SUBFLOW_FLAG_CONNECTED;
+ if (sf->map_valid)
+ flags |= MPTCP_SUBFLOW_FLAG_MAPVALID;
+
+ if (nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_TOKEN_REM, sf->remote_token) ||
+ nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_TOKEN_LOC, sf->token) ||
+ nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ,
+ sf->rel_write_seq) ||
+ nla_put_u64_64bit(skb, MPTCP_SUBFLOW_ATTR_MAP_SEQ, sf->map_seq,
+ MPTCP_SUBFLOW_ATTR_PAD) ||
+ nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_MAP_SFSEQ,
+ sf->map_subflow_seq) ||
+ nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_SSN_OFFSET, sf->ssn_offset) ||
+ nla_put_u16(skb, MPTCP_SUBFLOW_ATTR_MAP_DATALEN,
+ sf->map_data_len) ||
+ nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_FLAGS, flags) ||
+ nla_put_u8(skb, MPTCP_SUBFLOW_ATTR_ID_REM, sf->remote_id) ||
+ nla_put_u8(skb, MPTCP_SUBFLOW_ATTR_ID_LOC, sf->local_id)) {
+ err = -EMSGSIZE;
+ goto nla_failure;
+ }
+
+ rcu_read_unlock();
+ nla_nest_end(skb, start);
+ return 0;
+
+nla_failure:
+ rcu_read_unlock();
+ nla_nest_cancel(skb, start);
+ return err;
+}
+
+static size_t subflow_get_info_size(const struct sock *sk)
+{
+ size_t size = 0;
+
+ size += nla_total_size(0) + /* INET_ULP_INFO_MPTCP */
+ nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_TOKEN_REM */
+ nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_TOKEN_LOC */
+ nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ */
+ nla_total_size_64bit(8) + /* MPTCP_SUBFLOW_ATTR_MAP_SEQ */
+ nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_MAP_SFSEQ */
+ nla_total_size(2) + /* MPTCP_SUBFLOW_ATTR_SSN_OFFSET */
+ nla_total_size(2) + /* MPTCP_SUBFLOW_ATTR_MAP_DATALEN */
+ nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_FLAGS */
+ nla_total_size(1) + /* MPTCP_SUBFLOW_ATTR_ID_REM */
+ nla_total_size(1) + /* MPTCP_SUBFLOW_ATTR_ID_LOC */
+ 0;
+ return size;
+}
+
+void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops)
+{
+ ops->get_info = subflow_get_info;
+ ops->get_info_size = subflow_get_info_size;
+}
diff --git a/net/mptcp/mib.c b/net/mptcp/mib.c
new file mode 100644
index 000000000..b921cbdd9
--- /dev/null
+++ b/net/mptcp/mib.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/seq_file.h>
+#include <net/ip.h>
+#include <net/mptcp.h>
+#include <net/snmp.h>
+#include <net/net_namespace.h>
+
+#include "mib.h"
+
+static const struct snmp_mib mptcp_snmp_list[] = {
+ SNMP_MIB_ITEM("MPCapableSYNRX", MPTCP_MIB_MPCAPABLEPASSIVE),
+ SNMP_MIB_ITEM("MPCapableACKRX", MPTCP_MIB_MPCAPABLEPASSIVEACK),
+ SNMP_MIB_ITEM("MPCapableFallbackACK", MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK),
+ SNMP_MIB_ITEM("MPCapableFallbackSYNACK", MPTCP_MIB_MPCAPABLEACTIVEFALLBACK),
+ SNMP_MIB_ITEM("MPTCPRetrans", MPTCP_MIB_RETRANSSEGS),
+ SNMP_MIB_ITEM("MPJoinNoTokenFound", MPTCP_MIB_JOINNOTOKEN),
+ SNMP_MIB_ITEM("MPJoinSynRx", MPTCP_MIB_JOINSYNRX),
+ SNMP_MIB_ITEM("MPJoinSynAckRx", MPTCP_MIB_JOINSYNACKRX),
+ SNMP_MIB_ITEM("MPJoinSynAckHMacFailure", MPTCP_MIB_JOINSYNACKMAC),
+ SNMP_MIB_ITEM("MPJoinAckRx", MPTCP_MIB_JOINACKRX),
+ SNMP_MIB_ITEM("MPJoinAckHMacFailure", MPTCP_MIB_JOINACKMAC),
+ SNMP_MIB_ITEM("DSSNotMatching", MPTCP_MIB_DSSNOMATCH),
+ SNMP_MIB_ITEM("InfiniteMapRx", MPTCP_MIB_INFINITEMAPRX),
+ SNMP_MIB_ITEM("OFOQueueTail", MPTCP_MIB_OFOQUEUETAIL),
+ SNMP_MIB_ITEM("OFOQueue", MPTCP_MIB_OFOQUEUE),
+ SNMP_MIB_ITEM("OFOMerge", MPTCP_MIB_OFOMERGE),
+ SNMP_MIB_ITEM("NoDSSInWindow", MPTCP_MIB_NODSSWINDOW),
+ SNMP_MIB_ITEM("DuplicateData", MPTCP_MIB_DUPDATA),
+ SNMP_MIB_ITEM("AddAddr", MPTCP_MIB_ADDADDR),
+ SNMP_MIB_ITEM("EchoAdd", MPTCP_MIB_ECHOADD),
+ SNMP_MIB_ITEM("RmAddr", MPTCP_MIB_RMADDR),
+ SNMP_MIB_ITEM("RmSubflow", MPTCP_MIB_RMSUBFLOW),
+ SNMP_MIB_SENTINEL
+};
+
+/* mptcp_mib_alloc - allocate percpu mib counters
+ *
+ * These are allocated when the first mptcp socket is created so
+ * we do not waste percpu memory if mptcp isn't in use.
+ */
+bool mptcp_mib_alloc(struct net *net)
+{
+ struct mptcp_mib __percpu *mib = alloc_percpu(struct mptcp_mib);
+
+ if (!mib)
+ return false;
+
+ if (cmpxchg(&net->mib.mptcp_statistics, NULL, mib))
+ free_percpu(mib);
+
+ return true;
+}
+
+void mptcp_seq_show(struct seq_file *seq)
+{
+ struct net *net = seq->private;
+ int i;
+
+ seq_puts(seq, "MPTcpExt:");
+ for (i = 0; mptcp_snmp_list[i].name; i++)
+ seq_printf(seq, " %s", mptcp_snmp_list[i].name);
+
+ seq_puts(seq, "\nMPTcpExt:");
+
+ if (!net->mib.mptcp_statistics) {
+ for (i = 0; mptcp_snmp_list[i].name; i++)
+ seq_puts(seq, " 0");
+
+ seq_putc(seq, '\n');
+ return;
+ }
+
+ for (i = 0; mptcp_snmp_list[i].name; i++)
+ seq_printf(seq, " %lu",
+ snmp_fold_field(net->mib.mptcp_statistics,
+ mptcp_snmp_list[i].entry));
+ seq_putc(seq, '\n');
+}
diff --git a/net/mptcp/mib.h b/net/mptcp/mib.h
new file mode 100644
index 000000000..47bcecce1
--- /dev/null
+++ b/net/mptcp/mib.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+enum linux_mptcp_mib_field {
+ MPTCP_MIB_NUM = 0,
+ MPTCP_MIB_MPCAPABLEPASSIVE, /* Received SYN with MP_CAPABLE */
+ MPTCP_MIB_MPCAPABLEPASSIVEACK, /* Received third ACK with MP_CAPABLE */
+ MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK,/* Server-side fallback during 3-way handshake */
+ MPTCP_MIB_MPCAPABLEACTIVEFALLBACK, /* Client-side fallback during 3-way handshake */
+ MPTCP_MIB_RETRANSSEGS, /* Segments retransmitted at the MPTCP-level */
+ MPTCP_MIB_JOINNOTOKEN, /* Received MP_JOIN but the token was not found */
+ MPTCP_MIB_JOINSYNRX, /* Received a SYN + MP_JOIN */
+ MPTCP_MIB_JOINSYNACKRX, /* Received a SYN/ACK + MP_JOIN */
+ MPTCP_MIB_JOINSYNACKMAC, /* HMAC was wrong on SYN/ACK + MP_JOIN */
+ MPTCP_MIB_JOINACKRX, /* Received an ACK + MP_JOIN */
+ MPTCP_MIB_JOINACKMAC, /* HMAC was wrong on ACK + MP_JOIN */
+ MPTCP_MIB_DSSNOMATCH, /* Received a new mapping that did not match the previous one */
+ MPTCP_MIB_INFINITEMAPRX, /* Received an infinite mapping */
+ MPTCP_MIB_OFOQUEUETAIL, /* Segments inserted into OoO queue tail */
+ MPTCP_MIB_OFOQUEUE, /* Segments inserted into OoO queue */
+ MPTCP_MIB_OFOMERGE, /* Segments merged in OoO queue */
+ MPTCP_MIB_NODSSWINDOW, /* Segments not in MPTCP windows */
+ MPTCP_MIB_DUPDATA, /* Segments discarded due to duplicate DSS */
+ MPTCP_MIB_ADDADDR, /* Received ADD_ADDR with echo-flag=0 */
+ MPTCP_MIB_ECHOADD, /* Received ADD_ADDR with echo-flag=1 */
+ MPTCP_MIB_RMADDR, /* Received RM_ADDR */
+ MPTCP_MIB_RMSUBFLOW, /* Remove a subflow */
+ __MPTCP_MIB_MAX
+};
+
+#define LINUX_MIB_MPTCP_MAX __MPTCP_MIB_MAX
+struct mptcp_mib {
+ unsigned long mibs[LINUX_MIB_MPTCP_MAX];
+};
+
+static inline void MPTCP_INC_STATS(struct net *net,
+ enum linux_mptcp_mib_field field)
+{
+ if (likely(net->mib.mptcp_statistics))
+ SNMP_INC_STATS(net->mib.mptcp_statistics, field);
+}
+
+static inline void __MPTCP_INC_STATS(struct net *net,
+ enum linux_mptcp_mib_field field)
+{
+ if (likely(net->mib.mptcp_statistics))
+ __SNMP_INC_STATS(net->mib.mptcp_statistics, field);
+}
+
+bool mptcp_mib_alloc(struct net *net);
diff --git a/net/mptcp/mptcp_diag.c b/net/mptcp/mptcp_diag.c
new file mode 100644
index 000000000..f1af3f448
--- /dev/null
+++ b/net/mptcp/mptcp_diag.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0
+/* MPTCP socket monitoring support
+ *
+ * Copyright (c) 2020 Red Hat
+ *
+ * Author: Paolo Abeni <pabeni@redhat.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/net.h>
+#include <linux/inet_diag.h>
+#include <net/netlink.h>
+#include <uapi/linux/mptcp.h>
+#include "protocol.h"
+
+static int sk_diag_dump(struct sock *sk, struct sk_buff *skb,
+ struct netlink_callback *cb,
+ const struct inet_diag_req_v2 *req,
+ struct nlattr *bc, bool net_admin)
+{
+ if (!inet_diag_bc_sk(bc, sk))
+ return 0;
+
+ return inet_sk_diag_fill(sk, inet_csk(sk), skb, cb, req, NLM_F_MULTI,
+ net_admin);
+}
+
+static int mptcp_diag_dump_one(struct netlink_callback *cb,
+ const struct inet_diag_req_v2 *req)
+{
+ struct sk_buff *in_skb = cb->skb;
+ struct mptcp_sock *msk = NULL;
+ struct sk_buff *rep;
+ int err = -ENOENT;
+ struct net *net;
+ struct sock *sk;
+
+ net = sock_net(in_skb->sk);
+ msk = mptcp_token_get_sock(net, req->id.idiag_cookie[0]);
+ if (!msk)
+ goto out_nosk;
+
+ err = -ENOMEM;
+ sk = (struct sock *)msk;
+ rep = nlmsg_new(nla_total_size(sizeof(struct inet_diag_msg)) +
+ inet_diag_msg_attrs_size() +
+ nla_total_size(sizeof(struct mptcp_info)) +
+ nla_total_size(sizeof(struct inet_diag_meminfo)) + 64,
+ GFP_KERNEL);
+ if (!rep)
+ goto out;
+
+ err = inet_sk_diag_fill(sk, inet_csk(sk), rep, cb, req, 0,
+ netlink_net_capable(in_skb, CAP_NET_ADMIN));
+ if (err < 0) {
+ WARN_ON(err == -EMSGSIZE);
+ kfree_skb(rep);
+ goto out;
+ }
+ err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,
+ MSG_DONTWAIT);
+ if (err > 0)
+ err = 0;
+out:
+ sock_put(sk);
+
+out_nosk:
+ return err;
+}
+
+static void mptcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
+ const struct inet_diag_req_v2 *r)
+{
+ bool net_admin = netlink_net_capable(cb->skb, CAP_NET_ADMIN);
+ struct net *net = sock_net(skb->sk);
+ struct inet_diag_dump_data *cb_data;
+ struct mptcp_sock *msk;
+ struct nlattr *bc;
+
+ cb_data = cb->data;
+ bc = cb_data->inet_diag_nla_bc;
+
+ while ((msk = mptcp_token_iter_next(net, &cb->args[0], &cb->args[1])) !=
+ NULL) {
+ struct inet_sock *inet = (struct inet_sock *)msk;
+ struct sock *sk = (struct sock *)msk;
+ int ret = 0;
+
+ if (!(r->idiag_states & (1 << sk->sk_state)))
+ goto next;
+ if (r->sdiag_family != AF_UNSPEC &&
+ sk->sk_family != r->sdiag_family)
+ goto next;
+ if (r->id.idiag_sport != inet->inet_sport &&
+ r->id.idiag_sport)
+ goto next;
+ if (r->id.idiag_dport != inet->inet_dport &&
+ r->id.idiag_dport)
+ goto next;
+
+ ret = sk_diag_dump(sk, skb, cb, r, bc, net_admin);
+next:
+ sock_put(sk);
+ if (ret < 0) {
+ /* will retry on the same position */
+ cb->args[1]--;
+ break;
+ }
+ cond_resched();
+ }
+}
+
+static void mptcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
+ void *_info)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_info *info = _info;
+ u32 flags = 0;
+ bool slow;
+ u8 val;
+
+ r->idiag_rqueue = sk_rmem_alloc_get(sk);
+ r->idiag_wqueue = sk_wmem_alloc_get(sk);
+ if (!info)
+ return;
+
+ slow = lock_sock_fast(sk);
+ info->mptcpi_subflows = READ_ONCE(msk->pm.subflows);
+ info->mptcpi_add_addr_signal = READ_ONCE(msk->pm.add_addr_signaled);
+ info->mptcpi_add_addr_accepted = READ_ONCE(msk->pm.add_addr_accepted);
+ info->mptcpi_subflows_max = READ_ONCE(msk->pm.subflows_max);
+ val = READ_ONCE(msk->pm.add_addr_signal_max);
+ info->mptcpi_add_addr_signal_max = val;
+ val = READ_ONCE(msk->pm.add_addr_accept_max);
+ info->mptcpi_add_addr_accepted_max = val;
+ if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags))
+ flags |= MPTCP_INFO_FLAG_FALLBACK;
+ if (READ_ONCE(msk->can_ack))
+ flags |= MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED;
+ info->mptcpi_flags = flags;
+ info->mptcpi_token = READ_ONCE(msk->token);
+ info->mptcpi_write_seq = READ_ONCE(msk->write_seq);
+ info->mptcpi_snd_una = atomic64_read(&msk->snd_una);
+ info->mptcpi_rcv_nxt = READ_ONCE(msk->ack_seq);
+ unlock_sock_fast(sk, slow);
+}
+
+static const struct inet_diag_handler mptcp_diag_handler = {
+ .dump = mptcp_diag_dump,
+ .dump_one = mptcp_diag_dump_one,
+ .idiag_get_info = mptcp_diag_get_info,
+ .idiag_type = IPPROTO_MPTCP,
+ .idiag_info_size = sizeof(struct mptcp_info),
+};
+
+static int __init mptcp_diag_init(void)
+{
+ return inet_diag_register(&mptcp_diag_handler);
+}
+
+static void __exit mptcp_diag_exit(void)
+{
+ inet_diag_unregister(&mptcp_diag_handler);
+}
+
+module_init(mptcp_diag_init);
+module_exit(mptcp_diag_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-262 /* AF_INET - IPPROTO_MPTCP */);
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
new file mode 100644
index 000000000..c389d7e47
--- /dev/null
+++ b/net/mptcp/options.c
@@ -0,0 +1,1138 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ */
+
+#define pr_fmt(fmt) "MPTCP: " fmt
+
+#include <linux/kernel.h>
+#include <crypto/sha.h>
+#include <net/tcp.h>
+#include <net/mptcp.h>
+#include "protocol.h"
+#include "mib.h"
+
+static bool mptcp_cap_flag_sha256(u8 flags)
+{
+ return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256;
+}
+
+static void mptcp_parse_option(const struct sk_buff *skb,
+ const unsigned char *ptr, int opsize,
+ struct mptcp_options_received *mp_opt)
+{
+ u8 subtype = *ptr >> 4;
+ int expected_opsize;
+ u8 version;
+ u8 flags;
+
+ switch (subtype) {
+ case MPTCPOPT_MP_CAPABLE:
+ /* strict size checking */
+ if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
+ if (skb->len > tcp_hdr(skb)->doff << 2)
+ expected_opsize = TCPOLEN_MPTCP_MPC_ACK_DATA;
+ else
+ expected_opsize = TCPOLEN_MPTCP_MPC_ACK;
+ } else {
+ if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK)
+ expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK;
+ else
+ expected_opsize = TCPOLEN_MPTCP_MPC_SYN;
+ }
+ if (opsize != expected_opsize)
+ break;
+
+ /* try to be gentle vs future versions on the initial syn */
+ version = *ptr++ & MPTCP_VERSION_MASK;
+ if (opsize != TCPOLEN_MPTCP_MPC_SYN) {
+ if (version != MPTCP_SUPPORTED_VERSION)
+ break;
+ } else if (version < MPTCP_SUPPORTED_VERSION) {
+ break;
+ }
+
+ flags = *ptr++;
+ if (!mptcp_cap_flag_sha256(flags) ||
+ (flags & MPTCP_CAP_EXTENSIBILITY))
+ break;
+
+ /* RFC 6824, Section 3.1:
+ * "For the Checksum Required bit (labeled "A"), if either
+ * host requires the use of checksums, checksums MUST be used.
+ * In other words, the only way for checksums not to be used
+ * is if both hosts in their SYNs set A=0."
+ *
+ * Section 3.3.0:
+ * "If a checksum is not present when its use has been
+ * negotiated, the receiver MUST close the subflow with a RST as
+ * it is considered broken."
+ *
+ * We don't implement DSS checksum - fall back to TCP.
+ */
+ if (flags & MPTCP_CAP_CHECKSUM_REQD)
+ break;
+
+ mp_opt->mp_capable = 1;
+ if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) {
+ mp_opt->sndr_key = get_unaligned_be64(ptr);
+ ptr += 8;
+ }
+ if (opsize >= TCPOLEN_MPTCP_MPC_ACK) {
+ mp_opt->rcvr_key = get_unaligned_be64(ptr);
+ ptr += 8;
+ }
+ if (opsize == TCPOLEN_MPTCP_MPC_ACK_DATA) {
+ /* Section 3.1.:
+ * "the data parameters in a MP_CAPABLE are semantically
+ * equivalent to those in a DSS option and can be used
+ * interchangeably."
+ */
+ mp_opt->dss = 1;
+ mp_opt->use_map = 1;
+ mp_opt->mpc_map = 1;
+ mp_opt->use_ack = 0;
+ mp_opt->data_len = get_unaligned_be16(ptr);
+ ptr += 2;
+ }
+ pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d",
+ version, flags, opsize, mp_opt->sndr_key,
+ mp_opt->rcvr_key, mp_opt->data_len);
+ break;
+
+ case MPTCPOPT_MP_JOIN:
+ mp_opt->mp_join = 1;
+ if (opsize == TCPOLEN_MPTCP_MPJ_SYN) {
+ mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP;
+ mp_opt->join_id = *ptr++;
+ mp_opt->token = get_unaligned_be32(ptr);
+ ptr += 4;
+ mp_opt->nonce = get_unaligned_be32(ptr);
+ ptr += 4;
+ pr_debug("MP_JOIN bkup=%u, id=%u, token=%u, nonce=%u",
+ mp_opt->backup, mp_opt->join_id,
+ mp_opt->token, mp_opt->nonce);
+ } else if (opsize == TCPOLEN_MPTCP_MPJ_SYNACK) {
+ mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP;
+ mp_opt->join_id = *ptr++;
+ mp_opt->thmac = get_unaligned_be64(ptr);
+ ptr += 8;
+ mp_opt->nonce = get_unaligned_be32(ptr);
+ ptr += 4;
+ pr_debug("MP_JOIN bkup=%u, id=%u, thmac=%llu, nonce=%u",
+ mp_opt->backup, mp_opt->join_id,
+ mp_opt->thmac, mp_opt->nonce);
+ } else if (opsize == TCPOLEN_MPTCP_MPJ_ACK) {
+ ptr += 2;
+ memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN);
+ pr_debug("MP_JOIN hmac");
+ } else {
+ mp_opt->mp_join = 0;
+ }
+ break;
+
+ case MPTCPOPT_DSS:
+ pr_debug("DSS");
+ ptr++;
+
+ /* we must clear 'mpc_map' be able to detect MP_CAPABLE
+ * map vs DSS map in mptcp_incoming_options(), and reconstruct
+ * map info accordingly
+ */
+ mp_opt->mpc_map = 0;
+ flags = (*ptr++) & MPTCP_DSS_FLAG_MASK;
+ mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0;
+ mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0;
+ mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0;
+ mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0;
+ mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK);
+
+ pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d",
+ mp_opt->data_fin, mp_opt->dsn64,
+ mp_opt->use_map, mp_opt->ack64,
+ mp_opt->use_ack);
+
+ expected_opsize = TCPOLEN_MPTCP_DSS_BASE;
+
+ if (mp_opt->use_ack) {
+ if (mp_opt->ack64)
+ expected_opsize += TCPOLEN_MPTCP_DSS_ACK64;
+ else
+ expected_opsize += TCPOLEN_MPTCP_DSS_ACK32;
+ }
+
+ if (mp_opt->use_map) {
+ if (mp_opt->dsn64)
+ expected_opsize += TCPOLEN_MPTCP_DSS_MAP64;
+ else
+ expected_opsize += TCPOLEN_MPTCP_DSS_MAP32;
+ }
+
+ /* RFC 6824, Section 3.3:
+ * If a checksum is present, but its use had
+ * not been negotiated in the MP_CAPABLE handshake,
+ * the checksum field MUST be ignored.
+ */
+ if (opsize != expected_opsize &&
+ opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM)
+ break;
+
+ mp_opt->dss = 1;
+
+ if (mp_opt->use_ack) {
+ if (mp_opt->ack64) {
+ mp_opt->data_ack = get_unaligned_be64(ptr);
+ ptr += 8;
+ } else {
+ mp_opt->data_ack = get_unaligned_be32(ptr);
+ ptr += 4;
+ }
+
+ pr_debug("data_ack=%llu", mp_opt->data_ack);
+ }
+
+ if (mp_opt->use_map) {
+ if (mp_opt->dsn64) {
+ mp_opt->data_seq = get_unaligned_be64(ptr);
+ ptr += 8;
+ } else {
+ mp_opt->data_seq = get_unaligned_be32(ptr);
+ ptr += 4;
+ }
+
+ mp_opt->subflow_seq = get_unaligned_be32(ptr);
+ ptr += 4;
+
+ mp_opt->data_len = get_unaligned_be16(ptr);
+ ptr += 2;
+
+ pr_debug("data_seq=%llu subflow_seq=%u data_len=%u",
+ mp_opt->data_seq, mp_opt->subflow_seq,
+ mp_opt->data_len);
+ }
+
+ break;
+
+ case MPTCPOPT_ADD_ADDR:
+ mp_opt->echo = (*ptr++) & MPTCP_ADDR_ECHO;
+ if (!mp_opt->echo) {
+ if (opsize == TCPOLEN_MPTCP_ADD_ADDR ||
+ opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT)
+ mp_opt->family = MPTCP_ADDR_IPVERSION_4;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 ||
+ opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT)
+ mp_opt->family = MPTCP_ADDR_IPVERSION_6;
+#endif
+ else
+ break;
+ } else {
+ if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE ||
+ opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT)
+ mp_opt->family = MPTCP_ADDR_IPVERSION_4;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE ||
+ opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT)
+ mp_opt->family = MPTCP_ADDR_IPVERSION_6;
+#endif
+ else
+ break;
+ }
+
+ mp_opt->add_addr = 1;
+ mp_opt->addr_id = *ptr++;
+ pr_debug("ADD_ADDR: id=%d, echo=%d", mp_opt->addr_id, mp_opt->echo);
+ if (mp_opt->family == MPTCP_ADDR_IPVERSION_4) {
+ memcpy((u8 *)&mp_opt->addr.s_addr, (u8 *)ptr, 4);
+ ptr += 4;
+ if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT ||
+ opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) {
+ mp_opt->port = get_unaligned_be16(ptr);
+ ptr += 2;
+ }
+ }
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else {
+ memcpy(mp_opt->addr6.s6_addr, (u8 *)ptr, 16);
+ ptr += 16;
+ if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT ||
+ opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) {
+ mp_opt->port = get_unaligned_be16(ptr);
+ ptr += 2;
+ }
+ }
+#endif
+ if (!mp_opt->echo) {
+ mp_opt->ahmac = get_unaligned_be64(ptr);
+ ptr += 8;
+ }
+ break;
+
+ case MPTCPOPT_RM_ADDR:
+ if (opsize != TCPOLEN_MPTCP_RM_ADDR_BASE)
+ break;
+
+ ptr++;
+
+ mp_opt->rm_addr = 1;
+ mp_opt->rm_id = *ptr++;
+ pr_debug("RM_ADDR: id=%d", mp_opt->rm_id);
+ break;
+
+ default:
+ break;
+ }
+}
+
+void mptcp_get_options(const struct sk_buff *skb,
+ struct mptcp_options_received *mp_opt)
+{
+ const struct tcphdr *th = tcp_hdr(skb);
+ const unsigned char *ptr;
+ int length;
+
+ /* initialize option status */
+ mp_opt->mp_capable = 0;
+ mp_opt->mp_join = 0;
+ mp_opt->add_addr = 0;
+ mp_opt->ahmac = 0;
+ mp_opt->port = 0;
+ mp_opt->rm_addr = 0;
+ mp_opt->dss = 0;
+
+ length = (th->doff * 4) - sizeof(struct tcphdr);
+ ptr = (const unsigned char *)(th + 1);
+
+ while (length > 0) {
+ int opcode = *ptr++;
+ int opsize;
+
+ switch (opcode) {
+ case TCPOPT_EOL:
+ return;
+ case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
+ length--;
+ continue;
+ default:
+ if (length < 2)
+ return;
+ opsize = *ptr++;
+ if (opsize < 2) /* "silly options" */
+ return;
+ if (opsize > length)
+ return; /* don't parse partial options */
+ if (opcode == TCPOPT_MPTCP)
+ mptcp_parse_option(skb, ptr, opsize, mp_opt);
+ ptr += opsize - 2;
+ length -= opsize;
+ }
+ }
+}
+
+bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
+ unsigned int *size, struct mptcp_out_options *opts)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+
+ /* we will use snd_isn to detect first pkt [re]transmission
+ * in mptcp_established_options_mp()
+ */
+ subflow->snd_isn = TCP_SKB_CB(skb)->end_seq;
+ if (subflow->request_mptcp) {
+ opts->suboptions = OPTION_MPTCP_MPC_SYN;
+ *size = TCPOLEN_MPTCP_MPC_SYN;
+ return true;
+ } else if (subflow->request_join) {
+ pr_debug("remote_token=%u, nonce=%u", subflow->remote_token,
+ subflow->local_nonce);
+ opts->suboptions = OPTION_MPTCP_MPJ_SYN;
+ opts->join_id = subflow->local_id;
+ opts->token = subflow->remote_token;
+ opts->nonce = subflow->local_nonce;
+ opts->backup = subflow->request_bkup;
+ *size = TCPOLEN_MPTCP_MPJ_SYN;
+ return true;
+ }
+ return false;
+}
+
+/* MP_JOIN client subflow must wait for 4th ack before sending any data:
+ * TCP can't schedule delack timer before the subflow is fully established.
+ * MPTCP uses the delack timer to do 3rd ack retransmissions
+ */
+static void schedule_3rdack_retransmission(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct tcp_sock *tp = tcp_sk(sk);
+ unsigned long timeout;
+
+ /* reschedule with a timeout above RTT, as we must look only for drop */
+ if (tp->srtt_us)
+ timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1));
+ else
+ timeout = TCP_TIMEOUT_INIT;
+ timeout += jiffies;
+
+ WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
+ icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
+ icsk->icsk_ack.timeout = timeout;
+ sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
+}
+
+static void clear_3rdack_retransmission(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ sk_stop_timer(sk, &icsk->icsk_delack_timer);
+ icsk->icsk_ack.timeout = 0;
+ icsk->icsk_ack.ato = 0;
+ icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER);
+}
+
+static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
+ unsigned int *size,
+ unsigned int remaining,
+ struct mptcp_out_options *opts)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_ext *mpext;
+ unsigned int data_len;
+
+ /* When skb is not available, we better over-estimate the emitted
+ * options len. A full DSS option (28 bytes) is longer than
+ * TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so
+ * tell the caller to defer the estimate to
+ * mptcp_established_options_dss(), which will reserve enough space.
+ */
+ if (!skb)
+ return false;
+
+ /* MPC/MPJ needed only on 3rd ack packet */
+ if (subflow->fully_established ||
+ subflow->snd_isn != TCP_SKB_CB(skb)->seq)
+ return false;
+
+ if (subflow->mp_capable) {
+ mpext = mptcp_get_ext(skb);
+ data_len = mpext ? mpext->data_len : 0;
+
+ /* we will check ext_copy.data_len in mptcp_write_options() to
+ * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and
+ * TCPOLEN_MPTCP_MPC_ACK
+ */
+ opts->ext_copy.data_len = data_len;
+ opts->suboptions = OPTION_MPTCP_MPC_ACK;
+ opts->sndr_key = subflow->local_key;
+ opts->rcvr_key = subflow->remote_key;
+
+ /* Section 3.1.
+ * The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK
+ * packets that start the first subflow of an MPTCP connection,
+ * as well as the first packet that carries data
+ */
+ if (data_len > 0)
+ *size = ALIGN(TCPOLEN_MPTCP_MPC_ACK_DATA, 4);
+ else
+ *size = TCPOLEN_MPTCP_MPC_ACK;
+
+ pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d",
+ subflow, subflow->local_key, subflow->remote_key,
+ data_len);
+
+ return true;
+ } else if (subflow->mp_join) {
+ opts->suboptions = OPTION_MPTCP_MPJ_ACK;
+ memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN);
+ *size = TCPOLEN_MPTCP_MPJ_ACK;
+ pr_debug("subflow=%p", subflow);
+
+ schedule_3rdack_retransmission(sk);
+ return true;
+ }
+ return false;
+}
+
+static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
+ struct sk_buff *skb, struct mptcp_ext *ext)
+{
+ /* The write_seq value has already been incremented, so the actual
+ * sequence number for the DATA_FIN is one less.
+ */
+ u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1;
+
+ if (!ext->use_map || !skb->len) {
+ /* RFC6824 requires a DSS mapping with specific values
+ * if DATA_FIN is set but no data payload is mapped
+ */
+ ext->data_fin = 1;
+ ext->use_map = 1;
+ ext->dsn64 = 1;
+ ext->data_seq = data_fin_tx_seq;
+ ext->subflow_seq = 0;
+ ext->data_len = 1;
+ } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) {
+ /* If there's an existing DSS mapping and it is the
+ * final mapping, DATA_FIN consumes 1 additional byte of
+ * mapping space.
+ */
+ ext->data_fin = 1;
+ ext->data_len++;
+ }
+}
+
+static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
+ unsigned int *size,
+ unsigned int remaining,
+ struct mptcp_out_options *opts)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+ unsigned int dss_size = 0;
+ u64 snd_data_fin_enable;
+ struct mptcp_ext *mpext;
+ unsigned int ack_size;
+ bool ret = false;
+
+ mpext = skb ? mptcp_get_ext(skb) : NULL;
+ snd_data_fin_enable = READ_ONCE(msk->snd_data_fin_enable);
+
+ if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) {
+ unsigned int map_size;
+
+ map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64;
+
+ remaining -= map_size;
+ dss_size = map_size;
+ if (mpext)
+ opts->ext_copy = *mpext;
+
+ if (skb && snd_data_fin_enable)
+ mptcp_write_data_fin(subflow, skb, &opts->ext_copy);
+ ret = true;
+ }
+
+ /* passive sockets msk will set the 'can_ack' after accept(), even
+ * if the first subflow may have the already the remote key handy
+ */
+ opts->ext_copy.use_ack = 0;
+ if (!READ_ONCE(msk->can_ack)) {
+ *size = ALIGN(dss_size, 4);
+ return ret;
+ }
+
+ if (READ_ONCE(msk->use_64bit_ack)) {
+ ack_size = TCPOLEN_MPTCP_DSS_ACK64;
+ opts->ext_copy.data_ack = READ_ONCE(msk->ack_seq);
+ opts->ext_copy.ack64 = 1;
+ } else {
+ ack_size = TCPOLEN_MPTCP_DSS_ACK32;
+ opts->ext_copy.data_ack32 = (uint32_t)READ_ONCE(msk->ack_seq);
+ opts->ext_copy.ack64 = 0;
+ }
+ opts->ext_copy.use_ack = 1;
+
+ /* Add kind/length/subtype/flag overhead if mapping is not populated */
+ if (dss_size == 0)
+ ack_size += TCPOLEN_MPTCP_DSS_BASE;
+
+ dss_size += ack_size;
+
+ *size = ALIGN(dss_size, 4);
+ return true;
+}
+
+static u64 add_addr_generate_hmac(u64 key1, u64 key2, u8 addr_id,
+ struct in_addr *addr)
+{
+ u8 hmac[SHA256_DIGEST_SIZE];
+ u8 msg[7];
+
+ msg[0] = addr_id;
+ memcpy(&msg[1], &addr->s_addr, 4);
+ msg[5] = 0;
+ msg[6] = 0;
+
+ mptcp_crypto_hmac_sha(key1, key2, msg, 7, hmac);
+
+ return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static u64 add_addr6_generate_hmac(u64 key1, u64 key2, u8 addr_id,
+ struct in6_addr *addr)
+{
+ u8 hmac[SHA256_DIGEST_SIZE];
+ u8 msg[19];
+
+ msg[0] = addr_id;
+ memcpy(&msg[1], &addr->s6_addr, 16);
+ msg[17] = 0;
+ msg[18] = 0;
+
+ mptcp_crypto_hmac_sha(key1, key2, msg, 19, hmac);
+
+ return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
+}
+#endif
+
+static bool mptcp_established_options_add_addr(struct sock *sk,
+ unsigned int *size,
+ unsigned int remaining,
+ struct mptcp_out_options *opts)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+ struct mptcp_addr_info saddr;
+ bool echo;
+ int len;
+
+ if (!mptcp_pm_should_add_signal(msk) ||
+ !(mptcp_pm_add_addr_signal(msk, remaining, &saddr, &echo)))
+ return false;
+
+ len = mptcp_add_addr_len(saddr.family, echo);
+ if (remaining < len)
+ return false;
+
+ *size = len;
+ opts->addr_id = saddr.id;
+ if (saddr.family == AF_INET) {
+ opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
+ opts->addr = saddr.addr;
+ if (!echo) {
+ opts->ahmac = add_addr_generate_hmac(msk->local_key,
+ msk->remote_key,
+ opts->addr_id,
+ &opts->addr);
+ }
+ }
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (saddr.family == AF_INET6) {
+ opts->suboptions |= OPTION_MPTCP_ADD_ADDR6;
+ opts->addr6 = saddr.addr6;
+ if (!echo) {
+ opts->ahmac = add_addr6_generate_hmac(msk->local_key,
+ msk->remote_key,
+ opts->addr_id,
+ &opts->addr6);
+ }
+ }
+#endif
+ pr_debug("addr_id=%d, ahmac=%llu, echo=%d", opts->addr_id, opts->ahmac, echo);
+
+ return true;
+}
+
+static bool mptcp_established_options_rm_addr(struct sock *sk,
+ unsigned int *size,
+ unsigned int remaining,
+ struct mptcp_out_options *opts)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+ u8 rm_id;
+
+ if (!mptcp_pm_should_rm_signal(msk) ||
+ !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_id)))
+ return false;
+
+ if (remaining < TCPOLEN_MPTCP_RM_ADDR_BASE)
+ return false;
+
+ *size = TCPOLEN_MPTCP_RM_ADDR_BASE;
+ opts->suboptions |= OPTION_MPTCP_RM_ADDR;
+ opts->rm_id = rm_id;
+
+ pr_debug("rm_id=%d", opts->rm_id);
+
+ return true;
+}
+
+bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
+ unsigned int *size, unsigned int remaining,
+ struct mptcp_out_options *opts)
+{
+ unsigned int opt_size = 0;
+ bool ret = false;
+
+ opts->suboptions = 0;
+
+ if (unlikely(mptcp_check_fallback(sk)))
+ return false;
+
+ /* prevent adding of any MPTCP related options on reset packet
+ * until we support MP_TCPRST/MP_FASTCLOSE
+ */
+ if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST))
+ return false;
+
+ if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts))
+ ret = true;
+ else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining,
+ opts))
+ ret = true;
+
+ /* we reserved enough space for the above options, and exceeding the
+ * TCP option space would be fatal
+ */
+ if (WARN_ON_ONCE(opt_size > remaining))
+ return false;
+
+ *size += opt_size;
+ remaining -= opt_size;
+ if (mptcp_established_options_add_addr(sk, &opt_size, remaining, opts)) {
+ *size += opt_size;
+ remaining -= opt_size;
+ ret = true;
+ } else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) {
+ *size += opt_size;
+ remaining -= opt_size;
+ ret = true;
+ }
+
+ return ret;
+}
+
+bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
+ struct mptcp_out_options *opts)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+
+ if (subflow_req->mp_capable) {
+ opts->suboptions = OPTION_MPTCP_MPC_SYNACK;
+ opts->sndr_key = subflow_req->local_key;
+ *size = TCPOLEN_MPTCP_MPC_SYNACK;
+ pr_debug("subflow_req=%p, local_key=%llu",
+ subflow_req, subflow_req->local_key);
+ return true;
+ } else if (subflow_req->mp_join) {
+ opts->suboptions = OPTION_MPTCP_MPJ_SYNACK;
+ opts->backup = subflow_req->backup;
+ opts->join_id = subflow_req->local_id;
+ opts->thmac = subflow_req->thmac;
+ opts->nonce = subflow_req->local_nonce;
+ pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u",
+ subflow_req, opts->backup, opts->join_id,
+ opts->thmac, opts->nonce);
+ *size = TCPOLEN_MPTCP_MPJ_SYNACK;
+ return true;
+ }
+ return false;
+}
+
+static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
+ struct mptcp_subflow_context *subflow,
+ struct sk_buff *skb,
+ struct mptcp_options_received *mp_opt)
+{
+ /* here we can process OoO, in-window pkts, only in-sequence 4th ack
+ * will make the subflow fully established
+ */
+ if (likely(subflow->fully_established)) {
+ /* on passive sockets, check for 3rd ack retransmission
+ * note that msk is always set by subflow_syn_recv_sock()
+ * for mp_join subflows
+ */
+ if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 &&
+ TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq &&
+ subflow->mp_join && mp_opt->mp_join &&
+ READ_ONCE(msk->pm.server_side))
+ tcp_send_ack(ssk);
+ goto fully_established;
+ }
+
+ /* we must process OoO packets before the first subflow is fully
+ * established. OoO packets are instead a protocol violation
+ * for MP_JOIN subflows as the peer must not send any data
+ * before receiving the forth ack - cfr. RFC 8684 section 3.2.
+ */
+ if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) {
+ if (subflow->mp_join)
+ goto reset;
+ return subflow->mp_capable;
+ }
+
+ if (mp_opt->dss && mp_opt->use_ack) {
+ /* subflows are fully established as soon as we get any
+ * additional ack.
+ */
+ subflow->fully_established = 1;
+ WRITE_ONCE(msk->fully_established, true);
+ goto fully_established;
+ }
+
+ /* If the first established packet does not contain MP_CAPABLE + data
+ * then fallback to TCP. Fallback scenarios requires a reset for
+ * MP_JOIN subflows.
+ */
+ if (!mp_opt->mp_capable) {
+ if (subflow->mp_join)
+ goto reset;
+ subflow->mp_capable = 0;
+ pr_fallback(msk);
+ __mptcp_do_fallback(msk);
+ return false;
+ }
+
+ if (unlikely(!READ_ONCE(msk->pm.server_side)))
+ pr_warn_once("bogus mpc option on established client sk");
+ mptcp_subflow_fully_established(subflow, mp_opt);
+
+fully_established:
+ if (likely(subflow->pm_notified))
+ return true;
+
+ subflow->pm_notified = 1;
+ if (subflow->mp_join) {
+ clear_3rdack_retransmission(ssk);
+ mptcp_pm_subflow_established(msk, subflow);
+ } else {
+ mptcp_pm_fully_established(msk);
+ }
+ return true;
+
+reset:
+ mptcp_subflow_reset(ssk);
+ return false;
+}
+
+static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit)
+{
+ u32 old_ack32, cur_ack32;
+
+ if (use_64bit)
+ return cur_ack;
+
+ old_ack32 = (u32)old_ack;
+ cur_ack32 = (u32)cur_ack;
+ cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32;
+ if (unlikely(before(cur_ack32, old_ack32)))
+ return cur_ack + (1LL << 32);
+ return cur_ack;
+}
+
+static void update_una(struct mptcp_sock *msk,
+ struct mptcp_options_received *mp_opt)
+{
+ u64 new_snd_una, snd_una, old_snd_una = atomic64_read(&msk->snd_una);
+ u64 write_seq = READ_ONCE(msk->write_seq);
+
+ /* avoid ack expansion on update conflict, to reduce the risk of
+ * wrongly expanding to a future ack sequence number, which is way
+ * more dangerous than missing an ack
+ */
+ new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64);
+
+ /* ACK for data not even sent yet? Ignore. */
+ if (after64(new_snd_una, write_seq))
+ new_snd_una = old_snd_una;
+
+ while (after64(new_snd_una, old_snd_una)) {
+ snd_una = old_snd_una;
+ old_snd_una = atomic64_cmpxchg(&msk->snd_una, snd_una,
+ new_snd_una);
+ if (old_snd_una == snd_una) {
+ mptcp_data_acked((struct sock *)msk);
+ break;
+ }
+ }
+}
+
+bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit)
+{
+ /* Skip if DATA_FIN was already received.
+ * If updating simultaneously with the recvmsg loop, values
+ * should match. If they mismatch, the peer is misbehaving and
+ * we will prefer the most recent information.
+ */
+ if (READ_ONCE(msk->rcv_data_fin) || !READ_ONCE(msk->first))
+ return false;
+
+ WRITE_ONCE(msk->rcv_data_fin_seq,
+ expand_ack(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit));
+ WRITE_ONCE(msk->rcv_data_fin, 1);
+
+ return true;
+}
+
+static bool add_addr_hmac_valid(struct mptcp_sock *msk,
+ struct mptcp_options_received *mp_opt)
+{
+ u64 hmac = 0;
+
+ if (mp_opt->echo)
+ return true;
+
+ if (mp_opt->family == MPTCP_ADDR_IPVERSION_4)
+ hmac = add_addr_generate_hmac(msk->remote_key,
+ msk->local_key,
+ mp_opt->addr_id, &mp_opt->addr);
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else
+ hmac = add_addr6_generate_hmac(msk->remote_key,
+ msk->local_key,
+ mp_opt->addr_id, &mp_opt->addr6);
+#endif
+
+ pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n",
+ msk, (unsigned long long)hmac,
+ (unsigned long long)mp_opt->ahmac);
+
+ return hmac == mp_opt->ahmac;
+}
+
+void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+ struct mptcp_options_received mp_opt;
+ struct mptcp_ext *mpext;
+
+ if (__mptcp_check_fallback(msk))
+ return;
+
+ mptcp_get_options(skb, &mp_opt);
+ if (!check_fully_established(msk, sk, subflow, skb, &mp_opt))
+ return;
+
+ if (mp_opt.add_addr && add_addr_hmac_valid(msk, &mp_opt)) {
+ struct mptcp_addr_info addr;
+
+ addr.port = htons(mp_opt.port);
+ addr.id = mp_opt.addr_id;
+ if (mp_opt.family == MPTCP_ADDR_IPVERSION_4) {
+ addr.family = AF_INET;
+ addr.addr = mp_opt.addr;
+ }
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (mp_opt.family == MPTCP_ADDR_IPVERSION_6) {
+ addr.family = AF_INET6;
+ addr.addr6 = mp_opt.addr6;
+ }
+#endif
+ if (!mp_opt.echo) {
+ mptcp_pm_add_addr_received(msk, &addr);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR);
+ } else {
+ mptcp_pm_del_add_timer(msk, &addr);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD);
+ }
+ mp_opt.add_addr = 0;
+ }
+
+ if (mp_opt.rm_addr) {
+ mptcp_pm_rm_addr_received(msk, mp_opt.rm_id);
+ mp_opt.rm_addr = 0;
+ }
+
+ if (!mp_opt.dss)
+ return;
+
+ /* we can't wait for recvmsg() to update the ack_seq, otherwise
+ * monodirectional flows will stuck
+ */
+ if (mp_opt.use_ack)
+ update_una(msk, &mp_opt);
+
+ /* Zero-data-length packets are dropped by the caller and not
+ * propagated to the MPTCP layer, so the skb extension does not
+ * need to be allocated or populated. DATA_FIN information, if
+ * present, needs to be updated here before the skb is freed.
+ */
+ if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
+ if (mp_opt.data_fin && mp_opt.data_len == 1 &&
+ mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) &&
+ schedule_work(&msk->work))
+ sock_hold(subflow->conn);
+
+ return;
+ }
+
+ mpext = skb_ext_add(skb, SKB_EXT_MPTCP);
+ if (!mpext)
+ return;
+
+ memset(mpext, 0, sizeof(*mpext));
+
+ if (mp_opt.use_map) {
+ if (mp_opt.mpc_map) {
+ /* this is an MP_CAPABLE carrying MPTCP data
+ * we know this map the first chunk of data
+ */
+ mptcp_crypto_key_sha(subflow->remote_key, NULL,
+ &mpext->data_seq);
+ mpext->data_seq++;
+ mpext->subflow_seq = 1;
+ mpext->dsn64 = 1;
+ mpext->mpc_map = 1;
+ mpext->data_fin = 0;
+ } else {
+ mpext->data_seq = mp_opt.data_seq;
+ mpext->subflow_seq = mp_opt.subflow_seq;
+ mpext->dsn64 = mp_opt.dsn64;
+ mpext->data_fin = mp_opt.data_fin;
+ }
+ mpext->data_len = mp_opt.data_len;
+ mpext->use_map = 1;
+ }
+}
+
+void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts)
+{
+ if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK |
+ OPTION_MPTCP_MPC_ACK) & opts->suboptions) {
+ u8 len;
+
+ if (OPTION_MPTCP_MPC_SYN & opts->suboptions)
+ len = TCPOLEN_MPTCP_MPC_SYN;
+ else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions)
+ len = TCPOLEN_MPTCP_MPC_SYNACK;
+ else if (opts->ext_copy.data_len)
+ len = TCPOLEN_MPTCP_MPC_ACK_DATA;
+ else
+ len = TCPOLEN_MPTCP_MPC_ACK;
+
+ *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len,
+ MPTCP_SUPPORTED_VERSION,
+ MPTCP_CAP_HMAC_SHA256);
+
+ if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) &
+ opts->suboptions))
+ goto mp_capable_done;
+
+ put_unaligned_be64(opts->sndr_key, ptr);
+ ptr += 2;
+ if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions))
+ goto mp_capable_done;
+
+ put_unaligned_be64(opts->rcvr_key, ptr);
+ ptr += 2;
+ if (!opts->ext_copy.data_len)
+ goto mp_capable_done;
+
+ put_unaligned_be32(opts->ext_copy.data_len << 16 |
+ TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
+ ptr += 1;
+ }
+
+mp_capable_done:
+ if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
+ if (opts->ahmac)
+ *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
+ TCPOLEN_MPTCP_ADD_ADDR, 0,
+ opts->addr_id);
+ else
+ *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
+ TCPOLEN_MPTCP_ADD_ADDR_BASE,
+ MPTCP_ADDR_ECHO,
+ opts->addr_id);
+ memcpy((u8 *)ptr, (u8 *)&opts->addr.s_addr, 4);
+ ptr += 1;
+ if (opts->ahmac) {
+ put_unaligned_be64(opts->ahmac, ptr);
+ ptr += 2;
+ }
+ }
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) {
+ if (opts->ahmac)
+ *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
+ TCPOLEN_MPTCP_ADD_ADDR6, 0,
+ opts->addr_id);
+ else
+ *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
+ TCPOLEN_MPTCP_ADD_ADDR6_BASE,
+ MPTCP_ADDR_ECHO,
+ opts->addr_id);
+ memcpy((u8 *)ptr, opts->addr6.s6_addr, 16);
+ ptr += 4;
+ if (opts->ahmac) {
+ put_unaligned_be64(opts->ahmac, ptr);
+ ptr += 2;
+ }
+ }
+#endif
+
+ if (OPTION_MPTCP_RM_ADDR & opts->suboptions) {
+ *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR,
+ TCPOLEN_MPTCP_RM_ADDR_BASE,
+ 0, opts->rm_id);
+ }
+
+ if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) {
+ *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
+ TCPOLEN_MPTCP_MPJ_SYN,
+ opts->backup, opts->join_id);
+ put_unaligned_be32(opts->token, ptr);
+ ptr += 1;
+ put_unaligned_be32(opts->nonce, ptr);
+ ptr += 1;
+ }
+
+ if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) {
+ *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
+ TCPOLEN_MPTCP_MPJ_SYNACK,
+ opts->backup, opts->join_id);
+ put_unaligned_be64(opts->thmac, ptr);
+ ptr += 2;
+ put_unaligned_be32(opts->nonce, ptr);
+ ptr += 1;
+ }
+
+ if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) {
+ *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
+ TCPOLEN_MPTCP_MPJ_ACK, 0, 0);
+ memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN);
+ ptr += 5;
+ }
+
+ if (opts->ext_copy.use_ack || opts->ext_copy.use_map) {
+ struct mptcp_ext *mpext = &opts->ext_copy;
+ u8 len = TCPOLEN_MPTCP_DSS_BASE;
+ u8 flags = 0;
+
+ if (mpext->use_ack) {
+ flags = MPTCP_DSS_HAS_ACK;
+ if (mpext->ack64) {
+ len += TCPOLEN_MPTCP_DSS_ACK64;
+ flags |= MPTCP_DSS_ACK64;
+ } else {
+ len += TCPOLEN_MPTCP_DSS_ACK32;
+ }
+ }
+
+ if (mpext->use_map) {
+ len += TCPOLEN_MPTCP_DSS_MAP64;
+
+ /* Use only 64-bit mapping flags for now, add
+ * support for optional 32-bit mappings later.
+ */
+ flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64;
+ if (mpext->data_fin)
+ flags |= MPTCP_DSS_DATA_FIN;
+ }
+
+ *ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags);
+
+ if (mpext->use_ack) {
+ if (mpext->ack64) {
+ put_unaligned_be64(mpext->data_ack, ptr);
+ ptr += 2;
+ } else {
+ put_unaligned_be32(mpext->data_ack32, ptr);
+ ptr += 1;
+ }
+ }
+
+ if (mpext->use_map) {
+ put_unaligned_be64(mpext->data_seq, ptr);
+ ptr += 2;
+ put_unaligned_be32(mpext->subflow_seq, ptr);
+ ptr += 1;
+ put_unaligned_be32(mpext->data_len << 16 |
+ TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
+ }
+ }
+}
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
new file mode 100644
index 000000000..e19e1525e
--- /dev/null
+++ b/net/mptcp/pm.c
@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2019, Intel Corporation.
+ */
+#define pr_fmt(fmt) "MPTCP: " fmt
+
+#include <linux/kernel.h>
+#include <net/tcp.h>
+#include <net/mptcp.h>
+#include "protocol.h"
+
+/* path manager command handlers */
+
+int mptcp_pm_announce_addr(struct mptcp_sock *msk,
+ const struct mptcp_addr_info *addr,
+ bool echo)
+{
+ pr_debug("msk=%p, local_id=%d", msk, addr->id);
+
+ msk->pm.local = *addr;
+ WRITE_ONCE(msk->pm.add_addr_echo, echo);
+ WRITE_ONCE(msk->pm.add_addr_signal, true);
+ return 0;
+}
+
+int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id)
+{
+ pr_debug("msk=%p, local_id=%d", msk, local_id);
+
+ msk->pm.rm_id = local_id;
+ WRITE_ONCE(msk->pm.rm_addr_signal, true);
+ return 0;
+}
+
+int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 local_id)
+{
+ pr_debug("msk=%p, local_id=%d", msk, local_id);
+
+ spin_lock_bh(&msk->pm.lock);
+ mptcp_pm_nl_rm_subflow_received(msk, local_id);
+ spin_unlock_bh(&msk->pm.lock);
+ return 0;
+}
+
+/* path manager event handlers */
+
+void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side)
+{
+ struct mptcp_pm_data *pm = &msk->pm;
+
+ pr_debug("msk=%p, token=%u side=%d", msk, msk->token, server_side);
+
+ WRITE_ONCE(pm->server_side, server_side);
+}
+
+bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk)
+{
+ struct mptcp_pm_data *pm = &msk->pm;
+ int ret = 0;
+
+ pr_debug("msk=%p subflows=%d max=%d allow=%d", msk, pm->subflows,
+ pm->subflows_max, READ_ONCE(pm->accept_subflow));
+
+ /* try to avoid acquiring the lock below */
+ if (!READ_ONCE(pm->accept_subflow))
+ return false;
+
+ spin_lock_bh(&pm->lock);
+ if (READ_ONCE(pm->accept_subflow)) {
+ ret = pm->subflows < pm->subflows_max;
+ if (ret && ++pm->subflows == pm->subflows_max)
+ WRITE_ONCE(pm->accept_subflow, false);
+ }
+ spin_unlock_bh(&pm->lock);
+
+ return ret;
+}
+
+/* return true if the new status bit is currently cleared, that is, this event
+ * can be server, eventually by an already scheduled work
+ */
+static bool mptcp_pm_schedule_work(struct mptcp_sock *msk,
+ enum mptcp_pm_status new_status)
+{
+ pr_debug("msk=%p status=%x new=%lx", msk, msk->pm.status,
+ BIT(new_status));
+ if (msk->pm.status & BIT(new_status))
+ return false;
+
+ msk->pm.status |= BIT(new_status);
+ if (schedule_work(&msk->work))
+ sock_hold((struct sock *)msk);
+ return true;
+}
+
+void mptcp_pm_fully_established(struct mptcp_sock *msk)
+{
+ struct mptcp_pm_data *pm = &msk->pm;
+
+ pr_debug("msk=%p", msk);
+
+ /* try to avoid acquiring the lock below */
+ if (!READ_ONCE(pm->work_pending))
+ return;
+
+ spin_lock_bh(&pm->lock);
+
+ if (READ_ONCE(pm->work_pending))
+ mptcp_pm_schedule_work(msk, MPTCP_PM_ESTABLISHED);
+
+ spin_unlock_bh(&pm->lock);
+}
+
+void mptcp_pm_connection_closed(struct mptcp_sock *msk)
+{
+ pr_debug("msk=%p", msk);
+}
+
+void mptcp_pm_subflow_established(struct mptcp_sock *msk,
+ struct mptcp_subflow_context *subflow)
+{
+ struct mptcp_pm_data *pm = &msk->pm;
+
+ pr_debug("msk=%p", msk);
+
+ if (!READ_ONCE(pm->work_pending))
+ return;
+
+ spin_lock_bh(&pm->lock);
+
+ if (READ_ONCE(pm->work_pending))
+ mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED);
+
+ spin_unlock_bh(&pm->lock);
+}
+
+void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id)
+{
+ pr_debug("msk=%p", msk);
+}
+
+void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
+ const struct mptcp_addr_info *addr)
+{
+ struct mptcp_pm_data *pm = &msk->pm;
+
+ pr_debug("msk=%p remote_id=%d accept=%d", msk, addr->id,
+ READ_ONCE(pm->accept_addr));
+
+ spin_lock_bh(&pm->lock);
+
+ if (!READ_ONCE(pm->accept_addr))
+ mptcp_pm_announce_addr(msk, addr, true);
+ else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED))
+ pm->remote = *addr;
+
+ spin_unlock_bh(&pm->lock);
+}
+
+void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, u8 rm_id)
+{
+ struct mptcp_pm_data *pm = &msk->pm;
+
+ pr_debug("msk=%p remote_id=%d", msk, rm_id);
+
+ spin_lock_bh(&pm->lock);
+ mptcp_pm_schedule_work(msk, MPTCP_PM_RM_ADDR_RECEIVED);
+ pm->rm_id = rm_id;
+ spin_unlock_bh(&pm->lock);
+}
+
+/* path manager helpers */
+
+bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
+ struct mptcp_addr_info *saddr, bool *echo)
+{
+ int ret = false;
+
+ spin_lock_bh(&msk->pm.lock);
+
+ /* double check after the lock is acquired */
+ if (!mptcp_pm_should_add_signal(msk))
+ goto out_unlock;
+
+ *echo = READ_ONCE(msk->pm.add_addr_echo);
+
+ if (remaining < mptcp_add_addr_len(msk->pm.local.family, *echo))
+ goto out_unlock;
+
+ *saddr = msk->pm.local;
+ WRITE_ONCE(msk->pm.add_addr_signal, false);
+ ret = true;
+
+out_unlock:
+ spin_unlock_bh(&msk->pm.lock);
+ return ret;
+}
+
+bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
+ u8 *rm_id)
+{
+ int ret = false;
+
+ spin_lock_bh(&msk->pm.lock);
+
+ /* double check after the lock is acquired */
+ if (!mptcp_pm_should_rm_signal(msk))
+ goto out_unlock;
+
+ if (remaining < TCPOLEN_MPTCP_RM_ADDR_BASE)
+ goto out_unlock;
+
+ *rm_id = msk->pm.rm_id;
+ WRITE_ONCE(msk->pm.rm_addr_signal, false);
+ ret = true;
+
+out_unlock:
+ spin_unlock_bh(&msk->pm.lock);
+ return ret;
+}
+
+int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
+{
+ return mptcp_pm_nl_get_local_id(msk, skc);
+}
+
+void mptcp_pm_data_init(struct mptcp_sock *msk)
+{
+ msk->pm.add_addr_signaled = 0;
+ msk->pm.add_addr_accepted = 0;
+ msk->pm.local_addr_used = 0;
+ msk->pm.subflows = 0;
+ msk->pm.rm_id = 0;
+ WRITE_ONCE(msk->pm.work_pending, false);
+ WRITE_ONCE(msk->pm.add_addr_signal, false);
+ WRITE_ONCE(msk->pm.rm_addr_signal, false);
+ WRITE_ONCE(msk->pm.accept_addr, false);
+ WRITE_ONCE(msk->pm.accept_subflow, false);
+ WRITE_ONCE(msk->pm.add_addr_echo, false);
+ msk->pm.status = 0;
+
+ spin_lock_init(&msk->pm.lock);
+ INIT_LIST_HEAD(&msk->pm.anno_list);
+
+ mptcp_pm_nl_data_init(msk);
+}
+
+void __init mptcp_pm_init(void)
+{
+ mptcp_pm_nl_init();
+}
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
new file mode 100644
index 000000000..0d6f3d912
--- /dev/null
+++ b/net/mptcp/pm_netlink.c
@@ -0,0 +1,1139 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2020, Red Hat, Inc.
+ */
+
+#define pr_fmt(fmt) "MPTCP: " fmt
+
+#include <linux/inet.h>
+#include <linux/kernel.h>
+#include <net/tcp.h>
+#include <net/netns/generic.h>
+#include <net/mptcp.h>
+#include <net/genetlink.h>
+#include <uapi/linux/mptcp.h>
+
+#include "protocol.h"
+#include "mib.h"
+
+/* forward declaration */
+static struct genl_family mptcp_genl_family;
+
+static int pm_nl_pernet_id;
+
+struct mptcp_pm_addr_entry {
+ struct list_head list;
+ struct mptcp_addr_info addr;
+ struct rcu_head rcu;
+};
+
+struct mptcp_pm_add_entry {
+ struct list_head list;
+ struct mptcp_addr_info addr;
+ struct timer_list add_timer;
+ struct mptcp_sock *sock;
+ u8 retrans_times;
+};
+
+struct pm_nl_pernet {
+ /* protects pernet updates */
+ spinlock_t lock;
+ struct list_head local_addr_list;
+ unsigned int addrs;
+ unsigned int add_addr_signal_max;
+ unsigned int add_addr_accept_max;
+ unsigned int local_addr_max;
+ unsigned int subflows_max;
+ unsigned int next_id;
+};
+
+#define MPTCP_PM_ADDR_MAX 8
+#define ADD_ADDR_RETRANS_MAX 3
+
+static bool addresses_equal(const struct mptcp_addr_info *a,
+ struct mptcp_addr_info *b, bool use_port)
+{
+ bool addr_equals = false;
+
+ if (a->family != b->family)
+ return false;
+
+ if (a->family == AF_INET)
+ addr_equals = a->addr.s_addr == b->addr.s_addr;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else
+ addr_equals = !ipv6_addr_cmp(&a->addr6, &b->addr6);
+#endif
+
+ if (!addr_equals)
+ return false;
+ if (!use_port)
+ return true;
+
+ return a->port == b->port;
+}
+
+static bool address_zero(const struct mptcp_addr_info *addr)
+{
+ struct mptcp_addr_info zero;
+
+ memset(&zero, 0, sizeof(zero));
+ zero.family = addr->family;
+
+ return addresses_equal(addr, &zero, false);
+}
+
+static void local_address(const struct sock_common *skc,
+ struct mptcp_addr_info *addr)
+{
+ addr->port = 0;
+ addr->family = skc->skc_family;
+ if (addr->family == AF_INET)
+ addr->addr.s_addr = skc->skc_rcv_saddr;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (addr->family == AF_INET6)
+ addr->addr6 = skc->skc_v6_rcv_saddr;
+#endif
+}
+
+static void remote_address(const struct sock_common *skc,
+ struct mptcp_addr_info *addr)
+{
+ addr->family = skc->skc_family;
+ addr->port = skc->skc_dport;
+ if (addr->family == AF_INET)
+ addr->addr.s_addr = skc->skc_daddr;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (addr->family == AF_INET6)
+ addr->addr6 = skc->skc_v6_daddr;
+#endif
+}
+
+static bool lookup_subflow_by_saddr(const struct list_head *list,
+ struct mptcp_addr_info *saddr)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_addr_info cur;
+ struct sock_common *skc;
+
+ list_for_each_entry(subflow, list, node) {
+ skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow);
+
+ local_address(skc, &cur);
+ if (addresses_equal(&cur, saddr, false))
+ return true;
+ }
+
+ return false;
+}
+
+static struct mptcp_pm_addr_entry *
+select_local_address(const struct pm_nl_pernet *pernet,
+ struct mptcp_sock *msk)
+{
+ struct mptcp_pm_addr_entry *entry, *ret = NULL;
+
+ rcu_read_lock();
+ spin_lock_bh(&msk->join_list_lock);
+ list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+ if (!(entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW))
+ continue;
+
+ /* avoid any address already in use by subflows and
+ * pending join
+ */
+ if (entry->addr.family == ((struct sock *)msk)->sk_family &&
+ !lookup_subflow_by_saddr(&msk->conn_list, &entry->addr) &&
+ !lookup_subflow_by_saddr(&msk->join_list, &entry->addr)) {
+ ret = entry;
+ break;
+ }
+ }
+ spin_unlock_bh(&msk->join_list_lock);
+ rcu_read_unlock();
+ return ret;
+}
+
+static struct mptcp_pm_addr_entry *
+select_signal_address(struct pm_nl_pernet *pernet, unsigned int pos)
+{
+ struct mptcp_pm_addr_entry *entry, *ret = NULL;
+ int i = 0;
+
+ rcu_read_lock();
+ /* do not keep any additional per socket state, just signal
+ * the address list in order.
+ * Note: removal from the local address list during the msk life-cycle
+ * can lead to additional addresses not being announced.
+ */
+ list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+ if (!(entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL))
+ continue;
+ if (i++ == pos) {
+ ret = entry;
+ break;
+ }
+ }
+ rcu_read_unlock();
+ return ret;
+}
+
+static void check_work_pending(struct mptcp_sock *msk)
+{
+ if (msk->pm.add_addr_signaled == msk->pm.add_addr_signal_max &&
+ (msk->pm.local_addr_used == msk->pm.local_addr_max ||
+ msk->pm.subflows == msk->pm.subflows_max))
+ WRITE_ONCE(msk->pm.work_pending, false);
+}
+
+static struct mptcp_pm_add_entry *
+lookup_anno_list_by_saddr(struct mptcp_sock *msk,
+ struct mptcp_addr_info *addr)
+{
+ struct mptcp_pm_add_entry *entry;
+
+ list_for_each_entry(entry, &msk->pm.anno_list, list) {
+ if (addresses_equal(&entry->addr, addr, false))
+ return entry;
+ }
+
+ return NULL;
+}
+
+static void mptcp_pm_add_timer(struct timer_list *timer)
+{
+ struct mptcp_pm_add_entry *entry = from_timer(entry, timer, add_timer);
+ struct mptcp_sock *msk = entry->sock;
+ struct sock *sk = (struct sock *)msk;
+
+ pr_debug("msk=%p", msk);
+
+ if (!msk)
+ return;
+
+ if (inet_sk_state_load(sk) == TCP_CLOSE)
+ return;
+
+ if (!entry->addr.id)
+ return;
+
+ if (mptcp_pm_should_add_signal(msk)) {
+ sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8);
+ goto out;
+ }
+
+ spin_lock_bh(&msk->pm.lock);
+
+ if (!mptcp_pm_should_add_signal(msk)) {
+ pr_debug("retransmit ADD_ADDR id=%d", entry->addr.id);
+ mptcp_pm_announce_addr(msk, &entry->addr, false);
+ entry->retrans_times++;
+ }
+
+ if (entry->retrans_times < ADD_ADDR_RETRANS_MAX)
+ sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX);
+
+ spin_unlock_bh(&msk->pm.lock);
+
+out:
+ __sock_put(sk);
+}
+
+struct mptcp_pm_add_entry *
+mptcp_pm_del_add_timer(struct mptcp_sock *msk,
+ struct mptcp_addr_info *addr)
+{
+ struct mptcp_pm_add_entry *entry;
+ struct sock *sk = (struct sock *)msk;
+
+ spin_lock_bh(&msk->pm.lock);
+ entry = lookup_anno_list_by_saddr(msk, addr);
+ if (entry)
+ entry->retrans_times = ADD_ADDR_RETRANS_MAX;
+ spin_unlock_bh(&msk->pm.lock);
+
+ if (entry)
+ sk_stop_timer_sync(sk, &entry->add_timer);
+
+ return entry;
+}
+
+static bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
+ struct mptcp_pm_addr_entry *entry)
+{
+ struct mptcp_pm_add_entry *add_entry = NULL;
+ struct sock *sk = (struct sock *)msk;
+
+ if (lookup_anno_list_by_saddr(msk, &entry->addr))
+ return false;
+
+ add_entry = kmalloc(sizeof(*add_entry), GFP_ATOMIC);
+ if (!add_entry)
+ return false;
+
+ list_add(&add_entry->list, &msk->pm.anno_list);
+
+ add_entry->addr = entry->addr;
+ add_entry->sock = msk;
+ add_entry->retrans_times = 0;
+
+ timer_setup(&add_entry->add_timer, mptcp_pm_add_timer, 0);
+ sk_reset_timer(sk, &add_entry->add_timer, jiffies + TCP_RTO_MAX);
+
+ return true;
+}
+
+void mptcp_pm_free_anno_list(struct mptcp_sock *msk)
+{
+ struct mptcp_pm_add_entry *entry, *tmp;
+ struct sock *sk = (struct sock *)msk;
+ LIST_HEAD(free_list);
+
+ pr_debug("msk=%p", msk);
+
+ spin_lock_bh(&msk->pm.lock);
+ list_splice_init(&msk->pm.anno_list, &free_list);
+ spin_unlock_bh(&msk->pm.lock);
+
+ list_for_each_entry_safe(entry, tmp, &free_list, list) {
+ sk_stop_timer_sync(sk, &entry->add_timer);
+ kfree(entry);
+ }
+}
+
+static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
+{
+ struct mptcp_addr_info remote = { 0 };
+ struct sock *sk = (struct sock *)msk;
+ struct mptcp_pm_addr_entry *local;
+ struct pm_nl_pernet *pernet;
+
+ pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
+
+ pr_debug("local %d:%d signal %d:%d subflows %d:%d\n",
+ msk->pm.local_addr_used, msk->pm.local_addr_max,
+ msk->pm.add_addr_signaled, msk->pm.add_addr_signal_max,
+ msk->pm.subflows, msk->pm.subflows_max);
+
+ /* check first for announce */
+ if (msk->pm.add_addr_signaled < msk->pm.add_addr_signal_max) {
+ local = select_signal_address(pernet,
+ msk->pm.add_addr_signaled);
+
+ if (local) {
+ if (mptcp_pm_alloc_anno_list(msk, local)) {
+ msk->pm.add_addr_signaled++;
+ mptcp_pm_announce_addr(msk, &local->addr, false);
+ }
+ } else {
+ /* pick failed, avoid fourther attempts later */
+ msk->pm.local_addr_used = msk->pm.add_addr_signal_max;
+ }
+
+ check_work_pending(msk);
+ }
+
+ /* check if should create a new subflow */
+ if (msk->pm.local_addr_used < msk->pm.local_addr_max &&
+ msk->pm.subflows < msk->pm.subflows_max) {
+ remote_address((struct sock_common *)sk, &remote);
+
+ local = select_local_address(pernet, msk);
+ if (local) {
+ msk->pm.local_addr_used++;
+ msk->pm.subflows++;
+ check_work_pending(msk);
+ spin_unlock_bh(&msk->pm.lock);
+ __mptcp_subflow_connect(sk, &local->addr, &remote);
+ spin_lock_bh(&msk->pm.lock);
+ return;
+ }
+
+ /* lookup failed, avoid fourther attempts later */
+ msk->pm.local_addr_used = msk->pm.local_addr_max;
+ check_work_pending(msk);
+ }
+}
+
+void mptcp_pm_nl_fully_established(struct mptcp_sock *msk)
+{
+ mptcp_pm_create_subflow_or_signal_addr(msk);
+}
+
+void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk)
+{
+ mptcp_pm_create_subflow_or_signal_addr(msk);
+}
+
+void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
+{
+ struct sock *sk = (struct sock *)msk;
+ struct mptcp_addr_info remote;
+ struct mptcp_addr_info local;
+
+ pr_debug("accepted %d:%d remote family %d",
+ msk->pm.add_addr_accepted, msk->pm.add_addr_accept_max,
+ msk->pm.remote.family);
+ msk->pm.add_addr_accepted++;
+ msk->pm.subflows++;
+ if (msk->pm.add_addr_accepted >= msk->pm.add_addr_accept_max ||
+ msk->pm.subflows >= msk->pm.subflows_max)
+ WRITE_ONCE(msk->pm.accept_addr, false);
+
+ /* connect to the specified remote address, using whatever
+ * local address the routing configuration will pick.
+ */
+ remote = msk->pm.remote;
+ if (!remote.port)
+ remote.port = sk->sk_dport;
+ memset(&local, 0, sizeof(local));
+ local.family = remote.family;
+
+ spin_unlock_bh(&msk->pm.lock);
+ __mptcp_subflow_connect((struct sock *)msk, &local, &remote);
+ spin_lock_bh(&msk->pm.lock);
+
+ mptcp_pm_announce_addr(msk, &remote, true);
+}
+
+void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow, *tmp;
+ struct sock *sk = (struct sock *)msk;
+
+ pr_debug("address rm_id %d", msk->pm.rm_id);
+
+ if (!msk->pm.rm_id)
+ return;
+
+ if (list_empty(&msk->conn_list))
+ return;
+
+ list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+ int how = RCV_SHUTDOWN | SEND_SHUTDOWN;
+ long timeout = 0;
+
+ if (msk->pm.rm_id != subflow->remote_id)
+ continue;
+
+ spin_unlock_bh(&msk->pm.lock);
+ mptcp_subflow_shutdown(sk, ssk, how);
+ __mptcp_close_ssk(sk, ssk, subflow, timeout);
+ spin_lock_bh(&msk->pm.lock);
+
+ msk->pm.add_addr_accepted--;
+ msk->pm.subflows--;
+ WRITE_ONCE(msk->pm.accept_addr, true);
+
+ __MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMADDR);
+
+ break;
+ }
+}
+
+void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, u8 rm_id)
+{
+ struct mptcp_subflow_context *subflow, *tmp;
+ struct sock *sk = (struct sock *)msk;
+
+ pr_debug("subflow rm_id %d", rm_id);
+
+ if (!rm_id)
+ return;
+
+ if (list_empty(&msk->conn_list))
+ return;
+
+ list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+ int how = RCV_SHUTDOWN | SEND_SHUTDOWN;
+ long timeout = 0;
+
+ if (rm_id != subflow->local_id)
+ continue;
+
+ spin_unlock_bh(&msk->pm.lock);
+ mptcp_subflow_shutdown(sk, ssk, how);
+ __mptcp_close_ssk(sk, ssk, subflow, timeout);
+ spin_lock_bh(&msk->pm.lock);
+
+ msk->pm.local_addr_used--;
+ msk->pm.subflows--;
+
+ __MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMSUBFLOW);
+
+ break;
+ }
+}
+
+static bool address_use_port(struct mptcp_pm_addr_entry *entry)
+{
+ return (entry->addr.flags &
+ (MPTCP_PM_ADDR_FLAG_SIGNAL | MPTCP_PM_ADDR_FLAG_SUBFLOW)) ==
+ MPTCP_PM_ADDR_FLAG_SIGNAL;
+}
+
+static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
+ struct mptcp_pm_addr_entry *entry)
+{
+ struct mptcp_pm_addr_entry *cur;
+ int ret = -EINVAL;
+
+ spin_lock_bh(&pernet->lock);
+ /* to keep the code simple, don't do IDR-like allocation for address ID,
+ * just bail when we exceed limits
+ */
+ if (pernet->next_id > 255)
+ goto out;
+ if (pernet->addrs >= MPTCP_PM_ADDR_MAX)
+ goto out;
+
+ /* do not insert duplicate address, differentiate on port only
+ * singled addresses
+ */
+ list_for_each_entry(cur, &pernet->local_addr_list, list) {
+ if (addresses_equal(&cur->addr, &entry->addr,
+ address_use_port(entry) &&
+ address_use_port(cur)))
+ goto out;
+ }
+
+ if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)
+ pernet->add_addr_signal_max++;
+ if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)
+ pernet->local_addr_max++;
+
+ entry->addr.id = pernet->next_id++;
+ pernet->addrs++;
+ list_add_tail_rcu(&entry->list, &pernet->local_addr_list);
+ ret = entry->addr.id;
+
+out:
+ spin_unlock_bh(&pernet->lock);
+ return ret;
+}
+
+int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
+{
+ struct mptcp_pm_addr_entry *entry;
+ struct mptcp_addr_info skc_local;
+ struct mptcp_addr_info msk_local;
+ struct pm_nl_pernet *pernet;
+ int ret = -1;
+
+ if (WARN_ON_ONCE(!msk))
+ return -1;
+
+ /* The 0 ID mapping is defined by the first subflow, copied into the msk
+ * addr
+ */
+ local_address((struct sock_common *)msk, &msk_local);
+ local_address((struct sock_common *)skc, &skc_local);
+ if (addresses_equal(&msk_local, &skc_local, false))
+ return 0;
+
+ if (address_zero(&skc_local))
+ return 0;
+
+ pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
+ if (addresses_equal(&entry->addr, &skc_local, false)) {
+ ret = entry->addr.id;
+ break;
+ }
+ }
+ rcu_read_unlock();
+ if (ret >= 0)
+ return ret;
+
+ /* address not found, add to local list */
+ entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
+ if (!entry)
+ return -ENOMEM;
+
+ entry->addr = skc_local;
+ entry->addr.ifindex = 0;
+ entry->addr.flags = 0;
+ ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
+ if (ret < 0)
+ kfree(entry);
+
+ return ret;
+}
+
+void mptcp_pm_nl_data_init(struct mptcp_sock *msk)
+{
+ struct mptcp_pm_data *pm = &msk->pm;
+ struct pm_nl_pernet *pernet;
+ bool subflows;
+
+ pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
+
+ pm->add_addr_signal_max = READ_ONCE(pernet->add_addr_signal_max);
+ pm->add_addr_accept_max = READ_ONCE(pernet->add_addr_accept_max);
+ pm->local_addr_max = READ_ONCE(pernet->local_addr_max);
+ pm->subflows_max = READ_ONCE(pernet->subflows_max);
+ subflows = !!pm->subflows_max;
+ WRITE_ONCE(pm->work_pending, (!!pm->local_addr_max && subflows) ||
+ !!pm->add_addr_signal_max);
+ WRITE_ONCE(pm->accept_addr, !!pm->add_addr_accept_max && subflows);
+ WRITE_ONCE(pm->accept_subflow, subflows);
+}
+
+#define MPTCP_PM_CMD_GRP_OFFSET 0
+
+static const struct genl_multicast_group mptcp_pm_mcgrps[] = {
+ [MPTCP_PM_CMD_GRP_OFFSET] = { .name = MPTCP_PM_CMD_GRP_NAME, },
+};
+
+static const struct nla_policy
+mptcp_pm_addr_policy[MPTCP_PM_ADDR_ATTR_MAX + 1] = {
+ [MPTCP_PM_ADDR_ATTR_FAMILY] = { .type = NLA_U16, },
+ [MPTCP_PM_ADDR_ATTR_ID] = { .type = NLA_U8, },
+ [MPTCP_PM_ADDR_ATTR_ADDR4] = { .type = NLA_U32, },
+ [MPTCP_PM_ADDR_ATTR_ADDR6] =
+ NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)),
+ [MPTCP_PM_ADDR_ATTR_PORT] = { .type = NLA_U16 },
+ [MPTCP_PM_ADDR_ATTR_FLAGS] = { .type = NLA_U32 },
+ [MPTCP_PM_ADDR_ATTR_IF_IDX] = { .type = NLA_S32 },
+};
+
+static const struct nla_policy mptcp_pm_policy[MPTCP_PM_ATTR_MAX + 1] = {
+ [MPTCP_PM_ATTR_ADDR] =
+ NLA_POLICY_NESTED(mptcp_pm_addr_policy),
+ [MPTCP_PM_ATTR_RCV_ADD_ADDRS] = { .type = NLA_U32, },
+ [MPTCP_PM_ATTR_SUBFLOWS] = { .type = NLA_U32, },
+};
+
+static int mptcp_pm_family_to_addr(int family)
+{
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ if (family == AF_INET6)
+ return MPTCP_PM_ADDR_ATTR_ADDR6;
+#endif
+ return MPTCP_PM_ADDR_ATTR_ADDR4;
+}
+
+static int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
+ bool require_family,
+ struct mptcp_pm_addr_entry *entry)
+{
+ struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
+ int err, addr_addr;
+
+ if (!attr) {
+ GENL_SET_ERR_MSG(info, "missing address info");
+ return -EINVAL;
+ }
+
+ /* no validation needed - was already done via nested policy */
+ err = nla_parse_nested_deprecated(tb, MPTCP_PM_ADDR_ATTR_MAX, attr,
+ mptcp_pm_addr_policy, info->extack);
+ if (err)
+ return err;
+
+ memset(entry, 0, sizeof(*entry));
+ if (!tb[MPTCP_PM_ADDR_ATTR_FAMILY]) {
+ if (!require_family)
+ goto skip_family;
+
+ NL_SET_ERR_MSG_ATTR(info->extack, attr,
+ "missing family");
+ return -EINVAL;
+ }
+
+ entry->addr.family = nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_FAMILY]);
+ if (entry->addr.family != AF_INET
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ && entry->addr.family != AF_INET6
+#endif
+ ) {
+ NL_SET_ERR_MSG_ATTR(info->extack, attr,
+ "unknown address family");
+ return -EINVAL;
+ }
+ addr_addr = mptcp_pm_family_to_addr(entry->addr.family);
+ if (!tb[addr_addr]) {
+ NL_SET_ERR_MSG_ATTR(info->extack, attr,
+ "missing address data");
+ return -EINVAL;
+ }
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ if (entry->addr.family == AF_INET6)
+ entry->addr.addr6 = nla_get_in6_addr(tb[addr_addr]);
+ else
+#endif
+ entry->addr.addr.s_addr = nla_get_in_addr(tb[addr_addr]);
+
+skip_family:
+ if (tb[MPTCP_PM_ADDR_ATTR_IF_IDX]) {
+ u32 val = nla_get_s32(tb[MPTCP_PM_ADDR_ATTR_IF_IDX]);
+
+ entry->addr.ifindex = val;
+ }
+
+ if (tb[MPTCP_PM_ADDR_ATTR_ID])
+ entry->addr.id = nla_get_u8(tb[MPTCP_PM_ADDR_ATTR_ID]);
+
+ if (tb[MPTCP_PM_ADDR_ATTR_FLAGS])
+ entry->addr.flags = nla_get_u32(tb[MPTCP_PM_ADDR_ATTR_FLAGS]);
+
+ return 0;
+}
+
+static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
+{
+ return net_generic(genl_info_net(info), pm_nl_pernet_id);
+}
+
+static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
+{
+ struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
+ struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+ struct mptcp_pm_addr_entry addr, *entry;
+ int ret;
+
+ ret = mptcp_pm_parse_addr(attr, info, true, &addr);
+ if (ret < 0)
+ return ret;
+
+ entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+ if (!entry) {
+ GENL_SET_ERR_MSG(info, "can't allocate addr");
+ return -ENOMEM;
+ }
+
+ *entry = addr;
+ ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
+ if (ret < 0) {
+ GENL_SET_ERR_MSG(info, "too many addresses or duplicate one");
+ kfree(entry);
+ return ret;
+ }
+
+ return 0;
+}
+
+static struct mptcp_pm_addr_entry *
+__lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id)
+{
+ struct mptcp_pm_addr_entry *entry;
+
+ list_for_each_entry(entry, &pernet->local_addr_list, list) {
+ if (entry->addr.id == id)
+ return entry;
+ }
+ return NULL;
+}
+
+static bool remove_anno_list_by_saddr(struct mptcp_sock *msk,
+ struct mptcp_addr_info *addr)
+{
+ struct mptcp_pm_add_entry *entry;
+
+ entry = mptcp_pm_del_add_timer(msk, addr);
+ if (entry) {
+ list_del(&entry->list);
+ kfree(entry);
+ return true;
+ }
+
+ return false;
+}
+
+static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
+ struct mptcp_addr_info *addr,
+ bool force)
+{
+ bool ret;
+
+ ret = remove_anno_list_by_saddr(msk, addr);
+ if (ret || force) {
+ spin_lock_bh(&msk->pm.lock);
+ mptcp_pm_remove_addr(msk, addr->id);
+ spin_unlock_bh(&msk->pm.lock);
+ }
+ return ret;
+}
+
+static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
+ struct mptcp_addr_info *addr)
+{
+ struct mptcp_sock *msk;
+ long s_slot = 0, s_num = 0;
+
+ pr_debug("remove_id=%d", addr->id);
+
+ while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
+ struct sock *sk = (struct sock *)msk;
+ bool remove_subflow;
+
+ if (list_empty(&msk->conn_list)) {
+ mptcp_pm_remove_anno_addr(msk, addr, false);
+ goto next;
+ }
+
+ lock_sock(sk);
+ remove_subflow = lookup_subflow_by_saddr(&msk->conn_list, addr);
+ mptcp_pm_remove_anno_addr(msk, addr, remove_subflow);
+ if (remove_subflow)
+ mptcp_pm_remove_subflow(msk, addr->id);
+ release_sock(sk);
+
+next:
+ sock_put(sk);
+ cond_resched();
+ }
+
+ return 0;
+}
+
+static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info)
+{
+ struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
+ struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+ struct mptcp_pm_addr_entry addr, *entry;
+ int ret;
+
+ ret = mptcp_pm_parse_addr(attr, info, false, &addr);
+ if (ret < 0)
+ return ret;
+
+ spin_lock_bh(&pernet->lock);
+ entry = __lookup_addr_by_id(pernet, addr.addr.id);
+ if (!entry) {
+ GENL_SET_ERR_MSG(info, "address not found");
+ spin_unlock_bh(&pernet->lock);
+ return -EINVAL;
+ }
+ if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)
+ pernet->add_addr_signal_max--;
+ if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)
+ pernet->local_addr_max--;
+
+ pernet->addrs--;
+ list_del_rcu(&entry->list);
+ spin_unlock_bh(&pernet->lock);
+
+ mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), &entry->addr);
+ kfree_rcu(entry, rcu);
+
+ return ret;
+}
+
+static void __flush_addrs(struct pm_nl_pernet *pernet)
+{
+ while (!list_empty(&pernet->local_addr_list)) {
+ struct mptcp_pm_addr_entry *cur;
+
+ cur = list_entry(pernet->local_addr_list.next,
+ struct mptcp_pm_addr_entry, list);
+ list_del_rcu(&cur->list);
+ kfree_rcu(cur, rcu);
+ }
+}
+
+static void __reset_counters(struct pm_nl_pernet *pernet)
+{
+ pernet->add_addr_signal_max = 0;
+ pernet->add_addr_accept_max = 0;
+ pernet->local_addr_max = 0;
+ pernet->addrs = 0;
+}
+
+static int mptcp_nl_cmd_flush_addrs(struct sk_buff *skb, struct genl_info *info)
+{
+ struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+
+ spin_lock_bh(&pernet->lock);
+ __flush_addrs(pernet);
+ __reset_counters(pernet);
+ spin_unlock_bh(&pernet->lock);
+ return 0;
+}
+
+static int mptcp_nl_fill_addr(struct sk_buff *skb,
+ struct mptcp_pm_addr_entry *entry)
+{
+ struct mptcp_addr_info *addr = &entry->addr;
+ struct nlattr *attr;
+
+ attr = nla_nest_start(skb, MPTCP_PM_ATTR_ADDR);
+ if (!attr)
+ return -EMSGSIZE;
+
+ if (nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_FAMILY, addr->family))
+ goto nla_put_failure;
+ if (nla_put_u8(skb, MPTCP_PM_ADDR_ATTR_ID, addr->id))
+ goto nla_put_failure;
+ if (nla_put_u32(skb, MPTCP_PM_ADDR_ATTR_FLAGS, entry->addr.flags))
+ goto nla_put_failure;
+ if (entry->addr.ifindex &&
+ nla_put_s32(skb, MPTCP_PM_ADDR_ATTR_IF_IDX, entry->addr.ifindex))
+ goto nla_put_failure;
+
+ if (addr->family == AF_INET &&
+ nla_put_in_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR4,
+ addr->addr.s_addr))
+ goto nla_put_failure;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (addr->family == AF_INET6 &&
+ nla_put_in6_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR6, &addr->addr6))
+ goto nla_put_failure;
+#endif
+ nla_nest_end(skb, attr);
+ return 0;
+
+nla_put_failure:
+ nla_nest_cancel(skb, attr);
+ return -EMSGSIZE;
+}
+
+static int mptcp_nl_cmd_get_addr(struct sk_buff *skb, struct genl_info *info)
+{
+ struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
+ struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+ struct mptcp_pm_addr_entry addr, *entry;
+ struct sk_buff *msg;
+ void *reply;
+ int ret;
+
+ ret = mptcp_pm_parse_addr(attr, info, false, &addr);
+ if (ret < 0)
+ return ret;
+
+ msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
+ info->genlhdr->cmd);
+ if (!reply) {
+ GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
+ ret = -EMSGSIZE;
+ goto fail;
+ }
+
+ spin_lock_bh(&pernet->lock);
+ entry = __lookup_addr_by_id(pernet, addr.addr.id);
+ if (!entry) {
+ GENL_SET_ERR_MSG(info, "address not found");
+ ret = -EINVAL;
+ goto unlock_fail;
+ }
+
+ ret = mptcp_nl_fill_addr(msg, entry);
+ if (ret)
+ goto unlock_fail;
+
+ genlmsg_end(msg, reply);
+ ret = genlmsg_reply(msg, info);
+ spin_unlock_bh(&pernet->lock);
+ return ret;
+
+unlock_fail:
+ spin_unlock_bh(&pernet->lock);
+
+fail:
+ nlmsg_free(msg);
+ return ret;
+}
+
+static int mptcp_nl_cmd_dump_addrs(struct sk_buff *msg,
+ struct netlink_callback *cb)
+{
+ struct net *net = sock_net(msg->sk);
+ struct mptcp_pm_addr_entry *entry;
+ struct pm_nl_pernet *pernet;
+ int id = cb->args[0];
+ void *hdr;
+
+ pernet = net_generic(net, pm_nl_pernet_id);
+
+ spin_lock_bh(&pernet->lock);
+ list_for_each_entry(entry, &pernet->local_addr_list, list) {
+ if (entry->addr.id <= id)
+ continue;
+
+ hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).portid,
+ cb->nlh->nlmsg_seq, &mptcp_genl_family,
+ NLM_F_MULTI, MPTCP_PM_CMD_GET_ADDR);
+ if (!hdr)
+ break;
+
+ if (mptcp_nl_fill_addr(msg, entry) < 0) {
+ genlmsg_cancel(msg, hdr);
+ break;
+ }
+
+ id = entry->addr.id;
+ genlmsg_end(msg, hdr);
+ }
+ spin_unlock_bh(&pernet->lock);
+
+ cb->args[0] = id;
+ return msg->len;
+}
+
+static int parse_limit(struct genl_info *info, int id, unsigned int *limit)
+{
+ struct nlattr *attr = info->attrs[id];
+
+ if (!attr)
+ return 0;
+
+ *limit = nla_get_u32(attr);
+ if (*limit > MPTCP_PM_ADDR_MAX) {
+ GENL_SET_ERR_MSG(info, "limit greater than maximum");
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int
+mptcp_nl_cmd_set_limits(struct sk_buff *skb, struct genl_info *info)
+{
+ struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+ unsigned int rcv_addrs, subflows;
+ int ret;
+
+ spin_lock_bh(&pernet->lock);
+ rcv_addrs = pernet->add_addr_accept_max;
+ ret = parse_limit(info, MPTCP_PM_ATTR_RCV_ADD_ADDRS, &rcv_addrs);
+ if (ret)
+ goto unlock;
+
+ subflows = pernet->subflows_max;
+ ret = parse_limit(info, MPTCP_PM_ATTR_SUBFLOWS, &subflows);
+ if (ret)
+ goto unlock;
+
+ WRITE_ONCE(pernet->add_addr_accept_max, rcv_addrs);
+ WRITE_ONCE(pernet->subflows_max, subflows);
+
+unlock:
+ spin_unlock_bh(&pernet->lock);
+ return ret;
+}
+
+static int
+mptcp_nl_cmd_get_limits(struct sk_buff *skb, struct genl_info *info)
+{
+ struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+ struct sk_buff *msg;
+ void *reply;
+
+ msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
+ MPTCP_PM_CMD_GET_LIMITS);
+ if (!reply)
+ goto fail;
+
+ if (nla_put_u32(msg, MPTCP_PM_ATTR_RCV_ADD_ADDRS,
+ READ_ONCE(pernet->add_addr_accept_max)))
+ goto fail;
+
+ if (nla_put_u32(msg, MPTCP_PM_ATTR_SUBFLOWS,
+ READ_ONCE(pernet->subflows_max)))
+ goto fail;
+
+ genlmsg_end(msg, reply);
+ return genlmsg_reply(msg, info);
+
+fail:
+ GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
+ nlmsg_free(msg);
+ return -EMSGSIZE;
+}
+
+static const struct genl_small_ops mptcp_pm_ops[] = {
+ {
+ .cmd = MPTCP_PM_CMD_ADD_ADDR,
+ .doit = mptcp_nl_cmd_add_addr,
+ .flags = GENL_ADMIN_PERM,
+ },
+ {
+ .cmd = MPTCP_PM_CMD_DEL_ADDR,
+ .doit = mptcp_nl_cmd_del_addr,
+ .flags = GENL_ADMIN_PERM,
+ },
+ {
+ .cmd = MPTCP_PM_CMD_FLUSH_ADDRS,
+ .doit = mptcp_nl_cmd_flush_addrs,
+ .flags = GENL_ADMIN_PERM,
+ },
+ {
+ .cmd = MPTCP_PM_CMD_GET_ADDR,
+ .doit = mptcp_nl_cmd_get_addr,
+ .dumpit = mptcp_nl_cmd_dump_addrs,
+ },
+ {
+ .cmd = MPTCP_PM_CMD_SET_LIMITS,
+ .doit = mptcp_nl_cmd_set_limits,
+ .flags = GENL_ADMIN_PERM,
+ },
+ {
+ .cmd = MPTCP_PM_CMD_GET_LIMITS,
+ .doit = mptcp_nl_cmd_get_limits,
+ },
+};
+
+static struct genl_family mptcp_genl_family __ro_after_init = {
+ .name = MPTCP_PM_NAME,
+ .version = MPTCP_PM_VER,
+ .maxattr = MPTCP_PM_ATTR_MAX,
+ .policy = mptcp_pm_policy,
+ .netnsok = true,
+ .module = THIS_MODULE,
+ .small_ops = mptcp_pm_ops,
+ .n_small_ops = ARRAY_SIZE(mptcp_pm_ops),
+ .mcgrps = mptcp_pm_mcgrps,
+ .n_mcgrps = ARRAY_SIZE(mptcp_pm_mcgrps),
+};
+
+static int __net_init pm_nl_init_net(struct net *net)
+{
+ struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id);
+
+ INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
+ __reset_counters(pernet);
+ pernet->next_id = 1;
+ spin_lock_init(&pernet->lock);
+ return 0;
+}
+
+static void __net_exit pm_nl_exit_net(struct list_head *net_list)
+{
+ struct net *net;
+
+ list_for_each_entry(net, net_list, exit_list) {
+ /* net is removed from namespace list, can't race with
+ * other modifiers
+ */
+ __flush_addrs(net_generic(net, pm_nl_pernet_id));
+ }
+}
+
+static struct pernet_operations mptcp_pm_pernet_ops = {
+ .init = pm_nl_init_net,
+ .exit_batch = pm_nl_exit_net,
+ .id = &pm_nl_pernet_id,
+ .size = sizeof(struct pm_nl_pernet),
+};
+
+void __init mptcp_pm_nl_init(void)
+{
+ if (register_pernet_subsys(&mptcp_pm_pernet_ops) < 0)
+ panic("Failed to register MPTCP PM pernet subsystem.\n");
+
+ if (genl_register_family(&mptcp_genl_family))
+ panic("Failed to register MPTCP PM netlink family\n");
+}
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
new file mode 100644
index 000000000..72d944e6a
--- /dev/null
+++ b/net/mptcp/protocol.c
@@ -0,0 +1,2893 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ */
+
+#define pr_fmt(fmt) "MPTCP: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/sched/signal.h>
+#include <linux/atomic.h>
+#include <net/sock.h>
+#include <net/inet_common.h>
+#include <net/inet_hashtables.h>
+#include <net/protocol.h>
+#include <net/tcp.h>
+#include <net/tcp_states.h>
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+#include <net/transp_v6.h>
+#endif
+#include <net/mptcp.h>
+#include "protocol.h"
+#include "mib.h"
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+struct mptcp6_sock {
+ struct mptcp_sock msk;
+ struct ipv6_pinfo np;
+};
+#endif
+
+struct mptcp_skb_cb {
+ u64 map_seq;
+ u64 end_seq;
+ u32 offset;
+};
+
+#define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0]))
+
+static struct percpu_counter mptcp_sockets_allocated;
+
+/* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not
+ * completed yet or has failed, return the subflow socket.
+ * Otherwise return NULL.
+ */
+static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
+{
+ if (!msk->subflow || READ_ONCE(msk->can_ack))
+ return NULL;
+
+ return msk->subflow;
+}
+
+static bool mptcp_is_tcpsk(struct sock *sk)
+{
+ struct socket *sock = sk->sk_socket;
+
+ if (unlikely(sk->sk_prot == &tcp_prot)) {
+ /* we are being invoked after mptcp_accept() has
+ * accepted a non-mp-capable flow: sk is a tcp_sk,
+ * not an mptcp one.
+ *
+ * Hand the socket over to tcp so all further socket ops
+ * bypass mptcp.
+ */
+ sock->ops = &inet_stream_ops;
+ return true;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ } else if (unlikely(sk->sk_prot == &tcpv6_prot)) {
+ sock->ops = &inet6_stream_ops;
+ return true;
+#endif
+ }
+
+ return false;
+}
+
+static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk)
+{
+ sock_owned_by_me((const struct sock *)msk);
+
+ if (likely(!__mptcp_check_fallback(msk)))
+ return NULL;
+
+ return msk->first;
+}
+
+static int __mptcp_socket_create(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ struct socket *ssock;
+ int err;
+
+ err = mptcp_subflow_create_socket(sk, &ssock);
+ if (err)
+ return err;
+
+ msk->first = ssock->sk;
+ msk->subflow = ssock;
+ subflow = mptcp_subflow_ctx(ssock->sk);
+ list_add(&subflow->node, &msk->conn_list);
+ subflow->request_mptcp = 1;
+
+ /* accept() will wait on first subflow sk_wq, and we always wakes up
+ * via msk->sk_socket
+ */
+ RCU_INIT_POINTER(msk->first->sk_wq, &sk->sk_socket->wq);
+
+ return 0;
+}
+
+static void mptcp_drop(struct sock *sk, struct sk_buff *skb)
+{
+ sk_drops_add(sk, skb);
+ __kfree_skb(skb);
+}
+
+static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
+ struct sk_buff *from)
+{
+ bool fragstolen;
+ int delta;
+
+ if (MPTCP_SKB_CB(from)->offset ||
+ !skb_try_coalesce(to, from, &fragstolen, &delta))
+ return false;
+
+ pr_debug("colesced seq %llx into %llx new len %d new end seq %llx",
+ MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
+ to->len, MPTCP_SKB_CB(from)->end_seq);
+ MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
+ kfree_skb_partial(from, fragstolen);
+ atomic_add(delta, &sk->sk_rmem_alloc);
+ sk_mem_charge(sk, delta);
+ return true;
+}
+
+static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to,
+ struct sk_buff *from)
+{
+ if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq)
+ return false;
+
+ return mptcp_try_coalesce((struct sock *)msk, to, from);
+}
+
+/* "inspired" by tcp_data_queue_ofo(), main differences:
+ * - use mptcp seqs
+ * - don't cope with sacks
+ */
+static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb)
+{
+ struct sock *sk = (struct sock *)msk;
+ struct rb_node **p, *parent;
+ u64 seq, end_seq, max_seq;
+ struct sk_buff *skb1;
+ int space;
+
+ seq = MPTCP_SKB_CB(skb)->map_seq;
+ end_seq = MPTCP_SKB_CB(skb)->end_seq;
+ space = tcp_space(sk);
+ max_seq = space > 0 ? space + msk->ack_seq : msk->ack_seq;
+
+ pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq,
+ RB_EMPTY_ROOT(&msk->out_of_order_queue));
+ if (after64(seq, max_seq)) {
+ /* out of window */
+ mptcp_drop(sk, skb);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW);
+ return;
+ }
+
+ p = &msk->out_of_order_queue.rb_node;
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE);
+ if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) {
+ rb_link_node(&skb->rbnode, NULL, p);
+ rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
+ msk->ooo_last_skb = skb;
+ goto end;
+ }
+
+ /* with 2 subflows, adding at end of ooo queue is quite likely
+ * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
+ */
+ if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) {
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
+ return;
+ }
+
+ /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
+ if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) {
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL);
+ parent = &msk->ooo_last_skb->rbnode;
+ p = &parent->rb_right;
+ goto insert;
+ }
+
+ /* Find place to insert this segment. Handle overlaps on the way. */
+ parent = NULL;
+ while (*p) {
+ parent = *p;
+ skb1 = rb_to_skb(parent);
+ if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
+ p = &parent->rb_left;
+ continue;
+ }
+ if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) {
+ if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) {
+ /* All the bits are present. Drop. */
+ mptcp_drop(sk, skb);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
+ return;
+ }
+ if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) {
+ /* partial overlap:
+ * | skb |
+ * | skb1 |
+ * continue traversing
+ */
+ } else {
+ /* skb's seq == skb1's seq and skb covers skb1.
+ * Replace skb1 with skb.
+ */
+ rb_replace_node(&skb1->rbnode, &skb->rbnode,
+ &msk->out_of_order_queue);
+ mptcp_drop(sk, skb1);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
+ goto merge_right;
+ }
+ } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) {
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE);
+ return;
+ }
+ p = &parent->rb_right;
+ }
+
+insert:
+ /* Insert segment into RB tree. */
+ rb_link_node(&skb->rbnode, parent, p);
+ rb_insert_color(&skb->rbnode, &msk->out_of_order_queue);
+
+merge_right:
+ /* Remove other segments covered by skb. */
+ while ((skb1 = skb_rb_next(skb)) != NULL) {
+ if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq))
+ break;
+ rb_erase(&skb1->rbnode, &msk->out_of_order_queue);
+ mptcp_drop(sk, skb1);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
+ }
+ /* If there is no skb after us, we are the last_skb ! */
+ if (!skb1)
+ msk->ooo_last_skb = skb;
+
+end:
+ skb_condense(skb);
+ skb_set_owner_r(skb, sk);
+}
+
+static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
+ struct sk_buff *skb, unsigned int offset,
+ size_t copy_len)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct sock *sk = (struct sock *)msk;
+ struct sk_buff *tail;
+
+ __skb_unlink(skb, &ssk->sk_receive_queue);
+
+ skb_ext_reset(skb);
+ skb_orphan(skb);
+
+ /* try to fetch required memory from subflow */
+ if (!sk_rmem_schedule(sk, skb, skb->truesize)) {
+ int amount = sk_mem_pages(skb->truesize) << SK_MEM_QUANTUM_SHIFT;
+
+ if (ssk->sk_forward_alloc < amount)
+ goto drop;
+
+ ssk->sk_forward_alloc -= amount;
+ sk->sk_forward_alloc += amount;
+ }
+
+ /* the skb map_seq accounts for the skb offset:
+ * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq
+ * value
+ */
+ MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
+ MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len;
+ MPTCP_SKB_CB(skb)->offset = offset;
+
+ if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) {
+ /* in sequence */
+ WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
+ tail = skb_peek_tail(&sk->sk_receive_queue);
+ if (tail && mptcp_try_coalesce(sk, tail, skb))
+ return true;
+
+ skb_set_owner_r(skb, sk);
+ __skb_queue_tail(&sk->sk_receive_queue, skb);
+ return true;
+ } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) {
+ mptcp_data_queue_ofo(msk, skb);
+ return false;
+ }
+
+ /* old data, keep it simple and drop the whole pkt, sender
+ * will retransmit as needed, if needed.
+ */
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
+drop:
+ mptcp_drop(sk, skb);
+ return false;
+}
+
+static void mptcp_stop_timer(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
+ mptcp_sk(sk)->timer_ival = 0;
+}
+
+static void mptcp_check_data_fin_ack(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (__mptcp_check_fallback(msk))
+ return;
+
+ /* Look for an acknowledged DATA_FIN */
+ if (((1 << sk->sk_state) &
+ (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) &&
+ msk->write_seq == atomic64_read(&msk->snd_una)) {
+ mptcp_stop_timer(sk);
+
+ WRITE_ONCE(msk->snd_data_fin_enable, 0);
+
+ switch (sk->sk_state) {
+ case TCP_FIN_WAIT1:
+ inet_sk_state_store(sk, TCP_FIN_WAIT2);
+ sk->sk_state_change(sk);
+ break;
+ case TCP_CLOSING:
+ case TCP_LAST_ACK:
+ inet_sk_state_store(sk, TCP_CLOSE);
+ sk->sk_state_change(sk);
+ break;
+ }
+
+ if (sk->sk_shutdown == SHUTDOWN_MASK ||
+ sk->sk_state == TCP_CLOSE)
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
+ else
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
+ }
+}
+
+static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (READ_ONCE(msk->rcv_data_fin) &&
+ ((1 << sk->sk_state) &
+ (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) {
+ u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq);
+
+ if (msk->ack_seq == rcv_data_fin_seq) {
+ if (seq)
+ *seq = rcv_data_fin_seq;
+
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk)
+{
+ long tout = ssk && inet_csk(ssk)->icsk_pending ?
+ inet_csk(ssk)->icsk_timeout - jiffies : 0;
+
+ if (tout <= 0)
+ tout = mptcp_sk(sk)->timer_ival;
+ mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN;
+}
+
+static void mptcp_check_data_fin(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ u64 rcv_data_fin_seq;
+
+ if (__mptcp_check_fallback(msk) || !msk->first)
+ return;
+
+ /* Need to ack a DATA_FIN received from a peer while this side
+ * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
+ * msk->rcv_data_fin was set when parsing the incoming options
+ * at the subflow level and the msk lock was not held, so this
+ * is the first opportunity to act on the DATA_FIN and change
+ * the msk state.
+ *
+ * If we are caught up to the sequence number of the incoming
+ * DATA_FIN, send the DATA_ACK now and do state transition. If
+ * not caught up, do nothing and let the recv code send DATA_ACK
+ * when catching up.
+ */
+
+ if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
+ struct mptcp_subflow_context *subflow;
+
+ WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
+ WRITE_ONCE(msk->rcv_data_fin, 0);
+
+ sk->sk_shutdown |= RCV_SHUTDOWN;
+ smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+
+ switch (sk->sk_state) {
+ case TCP_ESTABLISHED:
+ inet_sk_state_store(sk, TCP_CLOSE_WAIT);
+ break;
+ case TCP_FIN_WAIT1:
+ inet_sk_state_store(sk, TCP_CLOSING);
+ break;
+ case TCP_FIN_WAIT2:
+ inet_sk_state_store(sk, TCP_CLOSE);
+ // @@ Close subflows now?
+ break;
+ default:
+ /* Other states not expected */
+ WARN_ON_ONCE(1);
+ break;
+ }
+
+ mptcp_set_timeout(sk, NULL);
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ lock_sock(ssk);
+ tcp_send_ack(ssk);
+ release_sock(ssk);
+ }
+
+ sk->sk_state_change(sk);
+
+ if (sk->sk_shutdown == SHUTDOWN_MASK ||
+ sk->sk_state == TCP_CLOSE)
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
+ else
+ sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
+ }
+}
+
+static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
+ struct sock *ssk,
+ unsigned int *bytes)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct sock *sk = (struct sock *)msk;
+ unsigned int moved = 0;
+ bool more_data_avail;
+ struct tcp_sock *tp;
+ u32 old_copied_seq;
+ bool done = false;
+
+ pr_debug("msk=%p ssk=%p", msk, ssk);
+ tp = tcp_sk(ssk);
+ old_copied_seq = tp->copied_seq;
+ do {
+ u32 map_remaining, offset;
+ u32 seq = tp->copied_seq;
+ struct sk_buff *skb;
+ bool fin;
+
+ /* try to move as much data as available */
+ map_remaining = subflow->map_data_len -
+ mptcp_subflow_get_map_offset(subflow);
+
+ skb = skb_peek(&ssk->sk_receive_queue);
+ if (!skb) {
+ /* if no data is found, a racing workqueue/recvmsg
+ * already processed the new data, stop here or we
+ * can enter an infinite loop
+ */
+ if (!moved)
+ done = true;
+ break;
+ }
+
+ if (__mptcp_check_fallback(msk)) {
+ /* if we are running under the workqueue, TCP could have
+ * collapsed skbs between dummy map creation and now
+ * be sure to adjust the size
+ */
+ map_remaining = skb->len;
+ subflow->map_data_len = skb->len;
+ }
+
+ offset = seq - TCP_SKB_CB(skb)->seq;
+ fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
+ if (fin) {
+ done = true;
+ seq++;
+ }
+
+ if (offset < skb->len) {
+ size_t len = skb->len - offset;
+
+ if (tp->urg_data)
+ done = true;
+
+ if (__mptcp_move_skb(msk, ssk, skb, offset, len))
+ moved += len;
+ seq += len;
+
+ if (WARN_ON_ONCE(map_remaining < len))
+ break;
+ } else {
+ WARN_ON_ONCE(!fin);
+ sk_eat_skb(ssk, skb);
+ done = true;
+ }
+
+ WRITE_ONCE(tp->copied_seq, seq);
+ more_data_avail = mptcp_subflow_data_available(ssk);
+
+ if (atomic_read(&sk->sk_rmem_alloc) > READ_ONCE(sk->sk_rcvbuf)) {
+ done = true;
+ break;
+ }
+ } while (more_data_avail);
+
+ *bytes += moved;
+ if (tp->copied_seq != old_copied_seq)
+ tcp_cleanup_rbuf(ssk, 1);
+
+ return done;
+}
+
+static bool mptcp_ofo_queue(struct mptcp_sock *msk)
+{
+ struct sock *sk = (struct sock *)msk;
+ struct sk_buff *skb, *tail;
+ bool moved = false;
+ struct rb_node *p;
+ u64 end_seq;
+
+ p = rb_first(&msk->out_of_order_queue);
+ pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue));
+ while (p) {
+ skb = rb_to_skb(p);
+ if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq))
+ break;
+
+ p = rb_next(p);
+ rb_erase(&skb->rbnode, &msk->out_of_order_queue);
+
+ if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq,
+ msk->ack_seq))) {
+ mptcp_drop(sk, skb);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA);
+ continue;
+ }
+
+ end_seq = MPTCP_SKB_CB(skb)->end_seq;
+ tail = skb_peek_tail(&sk->sk_receive_queue);
+ if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) {
+ int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq;
+
+ /* skip overlapping data, if any */
+ pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d",
+ MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq,
+ delta);
+ MPTCP_SKB_CB(skb)->offset += delta;
+ __skb_queue_tail(&sk->sk_receive_queue, skb);
+ }
+ msk->ack_seq = end_seq;
+ moved = true;
+ }
+ return moved;
+}
+
+/* In most cases we will be able to lock the mptcp socket. If its already
+ * owned, we need to defer to the work queue to avoid ABBA deadlock.
+ */
+static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
+{
+ struct sock *sk = (struct sock *)msk;
+ unsigned int moved = 0;
+
+ if (READ_ONCE(sk->sk_lock.owned))
+ return false;
+
+ if (unlikely(!spin_trylock_bh(&sk->sk_lock.slock)))
+ return false;
+
+ /* must re-check after taking the lock */
+ if (!READ_ONCE(sk->sk_lock.owned)) {
+ __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
+ mptcp_ofo_queue(msk);
+
+ /* If the moves have caught up with the DATA_FIN sequence number
+ * it's time to ack the DATA_FIN and change socket state, but
+ * this is not a good place to change state. Let the workqueue
+ * do it.
+ */
+ if (mptcp_pending_data_fin(sk, NULL) &&
+ schedule_work(&msk->work))
+ sock_hold(sk);
+ }
+
+ spin_unlock_bh(&sk->sk_lock.slock);
+
+ return moved > 0;
+}
+
+void mptcp_data_ready(struct sock *sk, struct sock *ssk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ bool wake;
+
+ /* move_skbs_to_msk below can legitly clear the data_avail flag,
+ * but we will need later to properly woke the reader, cache its
+ * value
+ */
+ wake = subflow->data_avail == MPTCP_SUBFLOW_DATA_AVAIL;
+ if (wake)
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+
+ if (atomic_read(&sk->sk_rmem_alloc) < READ_ONCE(sk->sk_rcvbuf) &&
+ move_skbs_to_msk(msk, ssk))
+ goto wake;
+
+ /* don't schedule if mptcp sk is (still) over limit */
+ if (atomic_read(&sk->sk_rmem_alloc) > READ_ONCE(sk->sk_rcvbuf))
+ goto wake;
+
+ /* mptcp socket is owned, release_cb should retry */
+ if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED,
+ &sk->sk_tsq_flags)) {
+ sock_hold(sk);
+
+ /* need to try again, its possible release_cb() has already
+ * been called after the test_and_set_bit() above.
+ */
+ move_skbs_to_msk(msk, ssk);
+ }
+wake:
+ if (wake)
+ sk->sk_data_ready(sk);
+}
+
+static void __mptcp_flush_join_list(struct mptcp_sock *msk)
+{
+ if (likely(list_empty(&msk->join_list)))
+ return;
+
+ spin_lock_bh(&msk->join_list_lock);
+ list_splice_tail_init(&msk->join_list, &msk->conn_list);
+ spin_unlock_bh(&msk->join_list_lock);
+}
+
+static bool mptcp_timer_pending(struct sock *sk)
+{
+ return timer_pending(&inet_csk(sk)->icsk_retransmit_timer);
+}
+
+static void mptcp_reset_timer(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ unsigned long tout;
+
+ /* should never be called with mptcp level timer cleared */
+ tout = READ_ONCE(mptcp_sk(sk)->timer_ival);
+ if (WARN_ON_ONCE(!tout))
+ tout = TCP_RTO_MIN;
+ sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout);
+}
+
+void mptcp_data_acked(struct sock *sk)
+{
+ mptcp_reset_timer(sk);
+
+ if ((!test_bit(MPTCP_SEND_SPACE, &mptcp_sk(sk)->flags) ||
+ (inet_sk_state_load(sk) != TCP_ESTABLISHED)) &&
+ schedule_work(&mptcp_sk(sk)->work))
+ sock_hold(sk);
+}
+
+void mptcp_subflow_eof(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (!test_and_set_bit(MPTCP_WORK_EOF, &msk->flags) &&
+ schedule_work(&msk->work))
+ sock_hold(sk);
+}
+
+static void mptcp_check_for_eof(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ int receivers = 0;
+
+ mptcp_for_each_subflow(msk, subflow)
+ receivers += !subflow->rx_eof;
+
+ if (!receivers && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
+ /* hopefully temporary hack: propagate shutdown status
+ * to msk, when all subflows agree on it
+ */
+ sk->sk_shutdown |= RCV_SHUTDOWN;
+
+ smp_mb__before_atomic(); /* SHUTDOWN must be visible first */
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+ sk->sk_data_ready(sk);
+ }
+}
+
+static bool mptcp_ext_cache_refill(struct mptcp_sock *msk)
+{
+ const struct sock *sk = (const struct sock *)msk;
+
+ if (!msk->cached_ext)
+ msk->cached_ext = __skb_ext_alloc(sk->sk_allocation);
+
+ return !!msk->cached_ext;
+}
+
+static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+
+ sock_owned_by_me(sk);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ if (subflow->data_avail)
+ return mptcp_subflow_tcp_sock(subflow);
+ }
+
+ return NULL;
+}
+
+static bool mptcp_skb_can_collapse_to(u64 write_seq,
+ const struct sk_buff *skb,
+ const struct mptcp_ext *mpext)
+{
+ if (!tcp_skb_can_collapse_to(skb))
+ return false;
+
+ /* can collapse only if MPTCP level sequence is in order */
+ return mpext && mpext->data_seq + mpext->data_len == write_seq;
+}
+
+/* we can append data to the given data frag if:
+ * - there is space available in the backing page_frag
+ * - the data frag tail matches the current page_frag free offset
+ * - the data frag end sequence number matches the current write seq
+ */
+static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk,
+ const struct page_frag *pfrag,
+ const struct mptcp_data_frag *df)
+{
+ return df && pfrag->page == df->page &&
+ pfrag->offset == (df->offset + df->data_len) &&
+ df->data_seq + df->data_len == msk->write_seq;
+}
+
+static void dfrag_uncharge(struct sock *sk, int len)
+{
+ sk_mem_uncharge(sk, len);
+ sk_wmem_queued_add(sk, -len);
+}
+
+static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag)
+{
+ int len = dfrag->data_len + dfrag->overhead;
+
+ list_del(&dfrag->list);
+ dfrag_uncharge(sk, len);
+ put_page(dfrag->page);
+}
+
+static bool mptcp_is_writeable(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+
+ if (!sk_stream_is_writeable((struct sock *)msk))
+ return false;
+
+ mptcp_for_each_subflow(msk, subflow) {
+ if (sk_stream_is_writeable(subflow->tcp_sock))
+ return true;
+ }
+ return false;
+}
+
+static void mptcp_clean_una(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_data_frag *dtmp, *dfrag;
+ bool cleaned = false;
+ u64 snd_una;
+
+ /* on fallback we just need to ignore snd_una, as this is really
+ * plain TCP
+ */
+ if (__mptcp_check_fallback(msk))
+ atomic64_set(&msk->snd_una, msk->write_seq);
+ snd_una = atomic64_read(&msk->snd_una);
+
+ list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) {
+ if (after64(dfrag->data_seq + dfrag->data_len, snd_una))
+ break;
+
+ dfrag_clear(sk, dfrag);
+ cleaned = true;
+ }
+
+ dfrag = mptcp_rtx_head(sk);
+ if (dfrag && after64(snd_una, dfrag->data_seq)) {
+ u64 delta = snd_una - dfrag->data_seq;
+
+ if (WARN_ON_ONCE(delta > dfrag->data_len))
+ goto out;
+
+ dfrag->data_seq += delta;
+ dfrag->offset += delta;
+ dfrag->data_len -= delta;
+
+ dfrag_uncharge(sk, delta);
+ cleaned = true;
+ }
+
+out:
+ if (cleaned) {
+ sk_mem_reclaim_partial(sk);
+
+ /* Only wake up writers if a subflow is ready */
+ if (mptcp_is_writeable(msk)) {
+ set_bit(MPTCP_SEND_SPACE, &mptcp_sk(sk)->flags);
+ smp_mb__after_atomic();
+
+ /* set SEND_SPACE before sk_stream_write_space clears
+ * NOSPACE
+ */
+ sk_stream_write_space(sk);
+ }
+ }
+}
+
+/* ensure we get enough memory for the frag hdr, beyond some minimal amount of
+ * data
+ */
+static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
+{
+ if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag),
+ pfrag, sk->sk_allocation)))
+ return true;
+
+ sk->sk_prot->enter_memory_pressure(sk);
+ sk_stream_moderate_sndbuf(sk);
+ return false;
+}
+
+static struct mptcp_data_frag *
+mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
+ int orig_offset)
+{
+ int offset = ALIGN(orig_offset, sizeof(long));
+ struct mptcp_data_frag *dfrag;
+
+ dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset);
+ dfrag->data_len = 0;
+ dfrag->data_seq = msk->write_seq;
+ dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
+ dfrag->offset = offset + sizeof(struct mptcp_data_frag);
+ dfrag->page = pfrag->page;
+
+ return dfrag;
+}
+
+static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
+ struct msghdr *msg, struct mptcp_data_frag *dfrag,
+ long *timeo, int *pmss_now,
+ int *ps_goal)
+{
+ int mss_now, avail_size, size_goal, offset, ret, frag_truesize = 0;
+ bool dfrag_collapsed, can_collapse = false;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_ext *mpext = NULL;
+ bool retransmission = !!dfrag;
+ struct sk_buff *skb, *tail;
+ struct page_frag *pfrag;
+ struct page *page;
+ u64 *write_seq;
+ size_t psize;
+
+ /* use the mptcp page cache so that we can easily move the data
+ * from one substream to another, but do per subflow memory accounting
+ * Note: pfrag is used only !retransmission, but the compiler if
+ * fooled into a warning if we don't init here
+ */
+ pfrag = sk_page_frag(sk);
+ if (!retransmission) {
+ write_seq = &msk->write_seq;
+ page = pfrag->page;
+ } else {
+ write_seq = &dfrag->data_seq;
+ page = dfrag->page;
+ }
+
+ /* compute copy limit */
+ mss_now = tcp_send_mss(ssk, &size_goal, msg->msg_flags);
+ *pmss_now = mss_now;
+ *ps_goal = size_goal;
+ avail_size = size_goal;
+ skb = tcp_write_queue_tail(ssk);
+ if (skb) {
+ mpext = skb_ext_find(skb, SKB_EXT_MPTCP);
+
+ /* Limit the write to the size available in the
+ * current skb, if any, so that we create at most a new skb.
+ * Explicitly tells TCP internals to avoid collapsing on later
+ * queue management operation, to avoid breaking the ext <->
+ * SSN association set here
+ */
+ can_collapse = (size_goal - skb->len > 0) &&
+ mptcp_skb_can_collapse_to(*write_seq, skb, mpext);
+ if (!can_collapse)
+ TCP_SKB_CB(skb)->eor = 1;
+ else
+ avail_size = size_goal - skb->len;
+ }
+
+ if (!retransmission) {
+ /* reuse tail pfrag, if possible, or carve a new one from the
+ * page allocator
+ */
+ dfrag = mptcp_rtx_tail(sk);
+ offset = pfrag->offset;
+ dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag);
+ if (!dfrag_collapsed) {
+ dfrag = mptcp_carve_data_frag(msk, pfrag, offset);
+ offset = dfrag->offset;
+ frag_truesize = dfrag->overhead;
+ }
+ psize = min_t(size_t, pfrag->size - offset, avail_size);
+
+ /* Copy to page */
+ pr_debug("left=%zu", msg_data_left(msg));
+ psize = copy_page_from_iter(pfrag->page, offset,
+ min_t(size_t, msg_data_left(msg),
+ psize),
+ &msg->msg_iter);
+ pr_debug("left=%zu", msg_data_left(msg));
+ if (!psize)
+ return -EINVAL;
+
+ if (!sk_wmem_schedule(sk, psize + dfrag->overhead)) {
+ iov_iter_revert(&msg->msg_iter, psize);
+ return -ENOMEM;
+ }
+ } else {
+ offset = dfrag->offset;
+ psize = min_t(size_t, dfrag->data_len, avail_size);
+ }
+
+ /* tell the TCP stack to delay the push so that we can safely
+ * access the skb after the sendpages call
+ */
+ ret = do_tcp_sendpages(ssk, page, offset, psize,
+ msg->msg_flags | MSG_SENDPAGE_NOTLAST | MSG_DONTWAIT);
+ if (ret <= 0) {
+ if (!retransmission)
+ iov_iter_revert(&msg->msg_iter, psize);
+ return ret;
+ }
+
+ frag_truesize += ret;
+ if (!retransmission) {
+ if (unlikely(ret < psize))
+ iov_iter_revert(&msg->msg_iter, psize - ret);
+
+ /* send successful, keep track of sent data for mptcp-level
+ * retransmission
+ */
+ dfrag->data_len += ret;
+ if (!dfrag_collapsed) {
+ get_page(dfrag->page);
+ list_add_tail(&dfrag->list, &msk->rtx_queue);
+ sk_wmem_queued_add(sk, frag_truesize);
+ } else {
+ sk_wmem_queued_add(sk, ret);
+ }
+
+ /* charge data on mptcp rtx queue to the master socket
+ * Note: we charge such data both to sk and ssk
+ */
+ sk->sk_forward_alloc -= frag_truesize;
+ }
+
+ /* if the tail skb extension is still the cached one, collapsing
+ * really happened. Note: we can't check for 'same skb' as the sk_buff
+ * hdr on tail can be transmitted, freed and re-allocated by the
+ * do_tcp_sendpages() call
+ */
+ tail = tcp_write_queue_tail(ssk);
+ if (mpext && tail && mpext == skb_ext_find(tail, SKB_EXT_MPTCP)) {
+ WARN_ON_ONCE(!can_collapse);
+ mpext->data_len += ret;
+ goto out;
+ }
+
+ skb = tcp_write_queue_tail(ssk);
+ mpext = __skb_ext_set(skb, SKB_EXT_MPTCP, msk->cached_ext);
+ msk->cached_ext = NULL;
+
+ memset(mpext, 0, sizeof(*mpext));
+ mpext->data_seq = *write_seq;
+ mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq;
+ mpext->data_len = ret;
+ mpext->use_map = 1;
+ mpext->dsn64 = 1;
+
+ pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d",
+ mpext->data_seq, mpext->subflow_seq, mpext->data_len,
+ mpext->dsn64);
+
+out:
+ if (!retransmission)
+ pfrag->offset += frag_truesize;
+ WRITE_ONCE(*write_seq, *write_seq + ret);
+ mptcp_subflow_ctx(ssk)->rel_write_seq += ret;
+
+ return ret;
+}
+
+static void mptcp_nospace(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+
+ clear_bit(MPTCP_SEND_SPACE, &msk->flags);
+ smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+ struct socket *sock = READ_ONCE(ssk->sk_socket);
+
+ /* enables ssk->write_space() callbacks */
+ if (sock)
+ set_bit(SOCK_NOSPACE, &sock->flags);
+ }
+}
+
+static bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
+{
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ /* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
+ if (subflow->request_join && !subflow->fully_established)
+ return false;
+
+ /* only send if our side has not closed yet */
+ return ((1 << ssk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
+}
+
+#define MPTCP_SEND_BURST_SIZE ((1 << 16) - \
+ sizeof(struct tcphdr) - \
+ MAX_TCP_OPTION_SPACE - \
+ sizeof(struct ipv6hdr) - \
+ sizeof(struct frag_hdr))
+
+struct subflow_send_info {
+ struct sock *ssk;
+ u64 ratio;
+};
+
+static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk,
+ u32 *sndbuf)
+{
+ struct subflow_send_info send_info[2];
+ struct mptcp_subflow_context *subflow;
+ int i, nr_active = 0;
+ struct sock *ssk;
+ u64 ratio;
+ u32 pace;
+
+ sock_owned_by_me((struct sock *)msk);
+
+ *sndbuf = 0;
+ if (!mptcp_ext_cache_refill(msk))
+ return NULL;
+
+ if (__mptcp_check_fallback(msk)) {
+ if (!msk->first)
+ return NULL;
+ *sndbuf = msk->first->sk_sndbuf;
+ return sk_stream_memory_free(msk->first) ? msk->first : NULL;
+ }
+
+ /* re-use last subflow, if the burst allow that */
+ if (msk->last_snd && msk->snd_burst > 0 &&
+ sk_stream_memory_free(msk->last_snd) &&
+ mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd))) {
+ mptcp_for_each_subflow(msk, subflow) {
+ ssk = mptcp_subflow_tcp_sock(subflow);
+ *sndbuf = max(tcp_sk(ssk)->snd_wnd, *sndbuf);
+ }
+ return msk->last_snd;
+ }
+
+ /* pick the subflow with the lower wmem/wspace ratio */
+ for (i = 0; i < 2; ++i) {
+ send_info[i].ssk = NULL;
+ send_info[i].ratio = -1;
+ }
+ mptcp_for_each_subflow(msk, subflow) {
+ ssk = mptcp_subflow_tcp_sock(subflow);
+ if (!mptcp_subflow_active(subflow))
+ continue;
+
+ nr_active += !subflow->backup;
+ *sndbuf = max(tcp_sk(ssk)->snd_wnd, *sndbuf);
+ if (!sk_stream_memory_free(subflow->tcp_sock))
+ continue;
+
+ pace = READ_ONCE(ssk->sk_pacing_rate);
+ if (!pace)
+ continue;
+
+ ratio = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32,
+ pace);
+ if (ratio < send_info[subflow->backup].ratio) {
+ send_info[subflow->backup].ssk = ssk;
+ send_info[subflow->backup].ratio = ratio;
+ }
+ }
+
+ pr_debug("msk=%p nr_active=%d ssk=%p:%lld backup=%p:%lld",
+ msk, nr_active, send_info[0].ssk, send_info[0].ratio,
+ send_info[1].ssk, send_info[1].ratio);
+
+ /* pick the best backup if no other subflow is active */
+ if (!nr_active)
+ send_info[0].ssk = send_info[1].ssk;
+
+ if (send_info[0].ssk) {
+ msk->last_snd = send_info[0].ssk;
+ msk->snd_burst = min_t(int, MPTCP_SEND_BURST_SIZE,
+ sk_stream_wspace(msk->last_snd));
+ return msk->last_snd;
+ }
+ return NULL;
+}
+
+static void ssk_check_wmem(struct mptcp_sock *msk)
+{
+ if (unlikely(!mptcp_is_writeable(msk)))
+ mptcp_nospace(msk);
+}
+
+static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
+{
+ int mss_now = 0, size_goal = 0, ret = 0;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct page_frag *pfrag;
+ size_t copied = 0;
+ struct sock *ssk;
+ u32 sndbuf;
+ bool tx_ok;
+ long timeo;
+
+ if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL))
+ return -EOPNOTSUPP;
+
+ lock_sock(sk);
+
+ timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
+
+ if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
+ ret = sk_stream_wait_connect(sk, &timeo);
+ if (ret)
+ goto out;
+ }
+
+ pfrag = sk_page_frag(sk);
+restart:
+ mptcp_clean_una(sk);
+
+ if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) {
+ ret = -EPIPE;
+ goto out;
+ }
+
+ __mptcp_flush_join_list(msk);
+ ssk = mptcp_subflow_get_send(msk, &sndbuf);
+ while (!sk_stream_memory_free(sk) ||
+ !ssk ||
+ !mptcp_page_frag_refill(ssk, pfrag)) {
+ if (ssk) {
+ /* make sure retransmit timer is
+ * running before we wait for memory.
+ *
+ * The retransmit timer might be needed
+ * to make the peer send an up-to-date
+ * MPTCP Ack.
+ */
+ mptcp_set_timeout(sk, ssk);
+ if (!mptcp_timer_pending(sk))
+ mptcp_reset_timer(sk);
+ }
+
+ mptcp_nospace(msk);
+ ret = sk_stream_wait_memory(sk, &timeo);
+ if (ret)
+ goto out;
+
+ mptcp_clean_una(sk);
+
+ ssk = mptcp_subflow_get_send(msk, &sndbuf);
+ if (list_empty(&msk->conn_list)) {
+ ret = -ENOTCONN;
+ goto out;
+ }
+ }
+
+ /* do auto tuning */
+ if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK) &&
+ sndbuf > READ_ONCE(sk->sk_sndbuf))
+ WRITE_ONCE(sk->sk_sndbuf, sndbuf);
+
+ pr_debug("conn_list->subflow=%p", ssk);
+
+ lock_sock(ssk);
+ tx_ok = msg_data_left(msg);
+ while (tx_ok) {
+ ret = mptcp_sendmsg_frag(sk, ssk, msg, NULL, &timeo, &mss_now,
+ &size_goal);
+ if (ret < 0) {
+ if (ret == -EAGAIN && timeo > 0) {
+ mptcp_set_timeout(sk, ssk);
+ release_sock(ssk);
+ goto restart;
+ }
+ break;
+ }
+
+ /* burst can be negative, we will try move to the next subflow
+ * at selection time, if possible.
+ */
+ msk->snd_burst -= ret;
+ copied += ret;
+
+ tx_ok = msg_data_left(msg);
+ if (!tx_ok)
+ break;
+
+ if (!sk_stream_memory_free(ssk) ||
+ !mptcp_page_frag_refill(ssk, pfrag) ||
+ !mptcp_ext_cache_refill(msk)) {
+ tcp_push(ssk, msg->msg_flags, mss_now,
+ tcp_sk(ssk)->nonagle, size_goal);
+ mptcp_set_timeout(sk, ssk);
+ release_sock(ssk);
+ goto restart;
+ }
+
+ /* memory is charged to mptcp level socket as well, i.e.
+ * if msg is very large, mptcp socket may run out of buffer
+ * space. mptcp_clean_una() will release data that has
+ * been acked at mptcp level in the mean time, so there is
+ * a good chance we can continue sending data right away.
+ *
+ * Normally, when the tcp subflow can accept more data, then
+ * so can the MPTCP socket. However, we need to cope with
+ * peers that might lag behind in their MPTCP-level
+ * acknowledgements, i.e. data might have been acked at
+ * tcp level only. So, we must also check the MPTCP socket
+ * limits before we send more data.
+ */
+ if (unlikely(!sk_stream_memory_free(sk))) {
+ tcp_push(ssk, msg->msg_flags, mss_now,
+ tcp_sk(ssk)->nonagle, size_goal);
+ mptcp_clean_una(sk);
+ if (!sk_stream_memory_free(sk)) {
+ /* can't send more for now, need to wait for
+ * MPTCP-level ACKs from peer.
+ *
+ * Wakeup will happen via mptcp_clean_una().
+ */
+ mptcp_set_timeout(sk, ssk);
+ release_sock(ssk);
+ goto restart;
+ }
+ }
+ }
+
+ mptcp_set_timeout(sk, ssk);
+ if (copied) {
+ tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle,
+ size_goal);
+
+ /* start the timer, if it's not pending */
+ if (!mptcp_timer_pending(sk))
+ mptcp_reset_timer(sk);
+ }
+
+ release_sock(ssk);
+out:
+ ssk_check_wmem(msk);
+ release_sock(sk);
+ return copied ? : ret;
+}
+
+static void mptcp_wait_data(struct sock *sk, long *timeo)
+{
+ DEFINE_WAIT_FUNC(wait, woken_wake_function);
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ add_wait_queue(sk_sleep(sk), &wait);
+ sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+
+ sk_wait_event(sk, timeo,
+ test_and_clear_bit(MPTCP_DATA_READY, &msk->flags), &wait);
+
+ sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+ remove_wait_queue(sk_sleep(sk), &wait);
+}
+
+static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk,
+ struct msghdr *msg,
+ size_t len)
+{
+ struct sock *sk = (struct sock *)msk;
+ struct sk_buff *skb;
+ int copied = 0;
+
+ while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
+ u32 offset = MPTCP_SKB_CB(skb)->offset;
+ u32 data_len = skb->len - offset;
+ u32 count = min_t(size_t, len - copied, data_len);
+ int err;
+
+ err = skb_copy_datagram_msg(skb, offset, msg, count);
+ if (unlikely(err < 0)) {
+ if (!copied)
+ return err;
+ break;
+ }
+
+ copied += count;
+
+ if (count < data_len) {
+ MPTCP_SKB_CB(skb)->offset += count;
+ break;
+ }
+
+ __skb_unlink(skb, &sk->sk_receive_queue);
+ __kfree_skb(skb);
+
+ if (copied >= len)
+ break;
+ }
+
+ return copied;
+}
+
+/* receive buffer autotuning. See tcp_rcv_space_adjust for more information.
+ *
+ * Only difference: Use highest rtt estimate of the subflows in use.
+ */
+static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ u32 time, advmss = 1;
+ u64 rtt_us, mstamp;
+
+ sock_owned_by_me(sk);
+
+ if (copied <= 0)
+ return;
+
+ msk->rcvq_space.copied += copied;
+
+ mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC);
+ time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time);
+
+ rtt_us = msk->rcvq_space.rtt_us;
+ if (rtt_us && time < (rtt_us >> 3))
+ return;
+
+ rtt_us = 0;
+ mptcp_for_each_subflow(msk, subflow) {
+ const struct tcp_sock *tp;
+ u64 sf_rtt_us;
+ u32 sf_advmss;
+
+ tp = tcp_sk(mptcp_subflow_tcp_sock(subflow));
+
+ sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us);
+ sf_advmss = READ_ONCE(tp->advmss);
+
+ rtt_us = max(sf_rtt_us, rtt_us);
+ advmss = max(sf_advmss, advmss);
+ }
+
+ msk->rcvq_space.rtt_us = rtt_us;
+ if (time < (rtt_us >> 3) || rtt_us == 0)
+ return;
+
+ if (msk->rcvq_space.copied <= msk->rcvq_space.space)
+ goto new_measure;
+
+ if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) &&
+ !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
+ int rcvmem, rcvbuf;
+ u64 rcvwin, grow;
+
+ rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss;
+
+ grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space);
+
+ do_div(grow, msk->rcvq_space.space);
+ rcvwin += (grow << 1);
+
+ rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER);
+ while (tcp_win_from_space(sk, rcvmem) < advmss)
+ rcvmem += 128;
+
+ do_div(rcvwin, advmss);
+ rcvbuf = min_t(u64, rcvwin * rcvmem,
+ READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]));
+
+ if (rcvbuf > sk->sk_rcvbuf) {
+ u32 window_clamp;
+
+ window_clamp = tcp_win_from_space(sk, rcvbuf);
+ WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
+
+ /* Make subflows follow along. If we do not do this, we
+ * get drops at subflow level if skbs can't be moved to
+ * the mptcp rx queue fast enough (announced rcv_win can
+ * exceed ssk->sk_rcvbuf).
+ */
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk;
+ bool slow;
+
+ ssk = mptcp_subflow_tcp_sock(subflow);
+ slow = lock_sock_fast(ssk);
+ WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
+ tcp_sk(ssk)->window_clamp = window_clamp;
+ tcp_cleanup_rbuf(ssk, 1);
+ unlock_sock_fast(ssk, slow);
+ }
+ }
+ }
+
+ msk->rcvq_space.space = msk->rcvq_space.copied;
+new_measure:
+ msk->rcvq_space.copied = 0;
+ msk->rcvq_space.time = mstamp;
+}
+
+static bool __mptcp_move_skbs(struct mptcp_sock *msk)
+{
+ unsigned int moved = 0;
+ bool done;
+
+ /* avoid looping forever below on racing close */
+ if (((struct sock *)msk)->sk_state == TCP_CLOSE)
+ return false;
+
+ __mptcp_flush_join_list(msk);
+ do {
+ struct sock *ssk = mptcp_subflow_recv_lookup(msk);
+
+ if (!ssk)
+ break;
+
+ lock_sock(ssk);
+ done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
+ release_sock(ssk);
+ } while (!done);
+
+ if (mptcp_ofo_queue(msk) || moved > 0) {
+ mptcp_check_data_fin((struct sock *)msk);
+ return true;
+ }
+ return false;
+}
+
+static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
+ int nonblock, int flags, int *addr_len)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ int copied = 0;
+ int target;
+ long timeo;
+
+ if (msg->msg_flags & ~(MSG_WAITALL | MSG_DONTWAIT))
+ return -EOPNOTSUPP;
+
+ lock_sock(sk);
+ timeo = sock_rcvtimeo(sk, nonblock);
+
+ len = min_t(size_t, len, INT_MAX);
+ target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
+ __mptcp_flush_join_list(msk);
+
+ while (len > (size_t)copied) {
+ int bytes_read;
+
+ bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied);
+ if (unlikely(bytes_read < 0)) {
+ if (!copied)
+ copied = bytes_read;
+ goto out_err;
+ }
+
+ copied += bytes_read;
+
+ if (skb_queue_empty(&sk->sk_receive_queue) &&
+ __mptcp_move_skbs(msk))
+ continue;
+
+ /* only the master socket status is relevant here. The exit
+ * conditions mirror closely tcp_recvmsg()
+ */
+ if (copied >= target)
+ break;
+
+ if (copied) {
+ if (sk->sk_err ||
+ sk->sk_state == TCP_CLOSE ||
+ (sk->sk_shutdown & RCV_SHUTDOWN) ||
+ !timeo ||
+ signal_pending(current))
+ break;
+ } else {
+ if (sk->sk_err) {
+ copied = sock_error(sk);
+ break;
+ }
+
+ if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
+ mptcp_check_for_eof(msk);
+
+ if (sk->sk_shutdown & RCV_SHUTDOWN)
+ break;
+
+ if (sk->sk_state == TCP_CLOSE) {
+ copied = -ENOTCONN;
+ break;
+ }
+
+ if (!timeo) {
+ copied = -EAGAIN;
+ break;
+ }
+
+ if (signal_pending(current)) {
+ copied = sock_intr_errno(timeo);
+ break;
+ }
+ }
+
+ pr_debug("block timeout %ld", timeo);
+ mptcp_wait_data(sk, &timeo);
+ }
+
+ if (skb_queue_empty(&sk->sk_receive_queue)) {
+ /* entire backlog drained, clear DATA_READY. */
+ clear_bit(MPTCP_DATA_READY, &msk->flags);
+
+ /* .. race-breaker: ssk might have gotten new data
+ * after last __mptcp_move_skbs() returned false.
+ */
+ if (unlikely(__mptcp_move_skbs(msk)))
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+ } else if (unlikely(!test_bit(MPTCP_DATA_READY, &msk->flags))) {
+ /* data to read but mptcp_wait_data() cleared DATA_READY */
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+ }
+out_err:
+ pr_debug("msk=%p data_ready=%d rx queue empty=%d copied=%d",
+ msk, test_bit(MPTCP_DATA_READY, &msk->flags),
+ skb_queue_empty(&sk->sk_receive_queue), copied);
+ mptcp_rcv_space_adjust(msk, copied);
+
+ release_sock(sk);
+ return copied;
+}
+
+static void mptcp_retransmit_handler(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (atomic64_read(&msk->snd_una) == READ_ONCE(msk->write_seq)) {
+ mptcp_stop_timer(sk);
+ } else {
+ set_bit(MPTCP_WORK_RTX, &msk->flags);
+ if (schedule_work(&msk->work))
+ sock_hold(sk);
+ }
+}
+
+static void mptcp_retransmit_timer(struct timer_list *t)
+{
+ struct inet_connection_sock *icsk = from_timer(icsk, t,
+ icsk_retransmit_timer);
+ struct sock *sk = &icsk->icsk_inet.sk;
+
+ bh_lock_sock(sk);
+ if (!sock_owned_by_user(sk)) {
+ mptcp_retransmit_handler(sk);
+ } else {
+ /* delegate our work to tcp_release_cb() */
+ if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED,
+ &sk->sk_tsq_flags))
+ sock_hold(sk);
+ }
+ bh_unlock_sock(sk);
+ sock_put(sk);
+}
+
+/* Find an idle subflow. Return NULL if there is unacked data at tcp
+ * level.
+ *
+ * A backup subflow is returned only if that is the only kind available.
+ */
+static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *backup = NULL;
+
+ sock_owned_by_me((const struct sock *)msk);
+
+ if (__mptcp_check_fallback(msk))
+ return msk->first;
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ if (!mptcp_subflow_active(subflow))
+ continue;
+
+ /* still data outstanding at TCP level? Don't retransmit. */
+ if (!tcp_write_queue_empty(ssk)) {
+ if (inet_csk(ssk)->icsk_ca_state >= TCP_CA_Loss)
+ continue;
+ return NULL;
+ }
+
+ if (subflow->backup) {
+ if (!backup)
+ backup = ssk;
+ continue;
+ }
+
+ return ssk;
+ }
+
+ return backup;
+}
+
+/* subflow sockets can be either outgoing (connect) or incoming
+ * (accept).
+ *
+ * Outgoing subflows use in-kernel sockets.
+ * Incoming subflows do not have their own 'struct socket' allocated,
+ * so we need to use tcp_close() after detaching them from the mptcp
+ * parent socket.
+ */
+void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
+ struct mptcp_subflow_context *subflow,
+ long timeout)
+{
+ struct socket *sock = READ_ONCE(ssk->sk_socket);
+
+ list_del(&subflow->node);
+
+ if (sock && sock != sk->sk_socket) {
+ /* outgoing subflow */
+ sock_release(sock);
+ } else {
+ /* incoming subflow */
+ tcp_close(ssk, timeout);
+ }
+}
+
+static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
+{
+ return 0;
+}
+
+static void pm_work(struct mptcp_sock *msk)
+{
+ struct mptcp_pm_data *pm = &msk->pm;
+
+ spin_lock_bh(&msk->pm.lock);
+
+ pr_debug("msk=%p status=%x", msk, pm->status);
+ if (pm->status & BIT(MPTCP_PM_ADD_ADDR_RECEIVED)) {
+ pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_RECEIVED);
+ mptcp_pm_nl_add_addr_received(msk);
+ }
+ if (pm->status & BIT(MPTCP_PM_RM_ADDR_RECEIVED)) {
+ pm->status &= ~BIT(MPTCP_PM_RM_ADDR_RECEIVED);
+ mptcp_pm_nl_rm_addr_received(msk);
+ }
+ if (pm->status & BIT(MPTCP_PM_ESTABLISHED)) {
+ pm->status &= ~BIT(MPTCP_PM_ESTABLISHED);
+ mptcp_pm_nl_fully_established(msk);
+ }
+ if (pm->status & BIT(MPTCP_PM_SUBFLOW_ESTABLISHED)) {
+ pm->status &= ~BIT(MPTCP_PM_SUBFLOW_ESTABLISHED);
+ mptcp_pm_nl_subflow_established(msk);
+ }
+
+ spin_unlock_bh(&msk->pm.lock);
+}
+
+static void __mptcp_close_subflow(struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow, *tmp;
+
+ list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ if (inet_sk_state_load(ssk) != TCP_CLOSE)
+ continue;
+
+ __mptcp_close_ssk((struct sock *)msk, ssk, subflow, 0);
+ }
+}
+
+static void mptcp_worker(struct work_struct *work)
+{
+ struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work);
+ struct sock *ssk, *sk = &msk->sk.icsk_inet.sk;
+ int orig_len, orig_offset, mss_now = 0, size_goal = 0;
+ struct mptcp_data_frag *dfrag;
+ u64 orig_write_seq;
+ size_t copied = 0;
+ struct msghdr msg = {
+ .msg_flags = MSG_DONTWAIT,
+ };
+ long timeo = 0;
+
+ lock_sock(sk);
+ mptcp_clean_una(sk);
+ mptcp_check_data_fin_ack(sk);
+ __mptcp_flush_join_list(msk);
+ if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
+ __mptcp_close_subflow(msk);
+
+ __mptcp_move_skbs(msk);
+
+ if (msk->pm.status)
+ pm_work(msk);
+
+ if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags))
+ mptcp_check_for_eof(msk);
+
+ mptcp_check_data_fin(sk);
+
+ if (!test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags))
+ goto unlock;
+
+ dfrag = mptcp_rtx_head(sk);
+ if (!dfrag)
+ goto unlock;
+
+ if (!mptcp_ext_cache_refill(msk))
+ goto reset_unlock;
+
+ ssk = mptcp_subflow_get_retrans(msk);
+ if (!ssk)
+ goto reset_unlock;
+
+ lock_sock(ssk);
+
+ orig_len = dfrag->data_len;
+ orig_offset = dfrag->offset;
+ orig_write_seq = dfrag->data_seq;
+ while (dfrag->data_len > 0) {
+ int ret = mptcp_sendmsg_frag(sk, ssk, &msg, dfrag, &timeo,
+ &mss_now, &size_goal);
+ if (ret < 0)
+ break;
+
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS);
+ copied += ret;
+ dfrag->data_len -= ret;
+ dfrag->offset += ret;
+
+ if (!mptcp_ext_cache_refill(msk))
+ break;
+ }
+ if (copied)
+ tcp_push(ssk, msg.msg_flags, mss_now, tcp_sk(ssk)->nonagle,
+ size_goal);
+
+ dfrag->data_seq = orig_write_seq;
+ dfrag->offset = orig_offset;
+ dfrag->data_len = orig_len;
+
+ mptcp_set_timeout(sk, ssk);
+ release_sock(ssk);
+
+reset_unlock:
+ if (!mptcp_timer_pending(sk))
+ mptcp_reset_timer(sk);
+
+unlock:
+ release_sock(sk);
+ sock_put(sk);
+}
+
+static int __mptcp_init_sock(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ spin_lock_init(&msk->join_list_lock);
+
+ INIT_LIST_HEAD(&msk->conn_list);
+ INIT_LIST_HEAD(&msk->join_list);
+ INIT_LIST_HEAD(&msk->rtx_queue);
+ __set_bit(MPTCP_SEND_SPACE, &msk->flags);
+ INIT_WORK(&msk->work, mptcp_worker);
+ msk->out_of_order_queue = RB_ROOT;
+
+ msk->first = NULL;
+ inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
+
+ mptcp_pm_data_init(msk);
+
+ /* re-use the csk retrans timer for MPTCP-level retrans */
+ timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
+
+ return 0;
+}
+
+static int mptcp_init_sock(struct sock *sk)
+{
+ struct net *net = sock_net(sk);
+ int ret;
+
+ ret = __mptcp_init_sock(sk);
+ if (ret)
+ return ret;
+
+ if (!mptcp_is_enabled(net))
+ return -ENOPROTOOPT;
+
+ if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net))
+ return -ENOMEM;
+
+ ret = __mptcp_socket_create(mptcp_sk(sk));
+ if (ret)
+ return ret;
+
+ sk_sockets_allocated_inc(sk);
+ sk->sk_rcvbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[1]);
+ sk->sk_sndbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[1]);
+
+ return 0;
+}
+
+static void __mptcp_clear_xmit(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_data_frag *dtmp, *dfrag;
+
+ sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer);
+
+ list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list)
+ dfrag_clear(sk, dfrag);
+}
+
+static void mptcp_cancel_work(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (cancel_work_sync(&msk->work))
+ sock_put(sk);
+}
+
+void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
+{
+ lock_sock(ssk);
+
+ switch (ssk->sk_state) {
+ case TCP_LISTEN:
+ if (!(how & RCV_SHUTDOWN))
+ break;
+ fallthrough;
+ case TCP_SYN_SENT:
+ tcp_disconnect(ssk, O_NONBLOCK);
+ break;
+ default:
+ if (__mptcp_check_fallback(mptcp_sk(sk))) {
+ pr_debug("Fallback");
+ ssk->sk_shutdown |= how;
+ tcp_shutdown(ssk, how);
+ } else {
+ pr_debug("Sending DATA_FIN on subflow %p", ssk);
+ mptcp_set_timeout(sk, ssk);
+ tcp_send_ack(ssk);
+ }
+ break;
+ }
+
+ release_sock(ssk);
+}
+
+static const unsigned char new_state[16] = {
+ /* current state: new state: action: */
+ [0 /* (Invalid) */] = TCP_CLOSE,
+ [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
+ [TCP_SYN_SENT] = TCP_CLOSE,
+ [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
+ [TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
+ [TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
+ [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */
+ [TCP_CLOSE] = TCP_CLOSE,
+ [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
+ [TCP_LAST_ACK] = TCP_LAST_ACK,
+ [TCP_LISTEN] = TCP_CLOSE,
+ [TCP_CLOSING] = TCP_CLOSING,
+ [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
+};
+
+static int mptcp_close_state(struct sock *sk)
+{
+ int next = (int)new_state[sk->sk_state];
+ int ns = next & TCP_STATE_MASK;
+
+ inet_sk_state_store(sk, ns);
+
+ return next & TCP_ACTION_FIN;
+}
+
+static void mptcp_close(struct sock *sk, long timeout)
+{
+ struct mptcp_subflow_context *subflow, *tmp;
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ LIST_HEAD(conn_list);
+
+ lock_sock(sk);
+ sk->sk_shutdown = SHUTDOWN_MASK;
+
+ if (sk->sk_state == TCP_LISTEN) {
+ inet_sk_state_store(sk, TCP_CLOSE);
+ goto cleanup;
+ } else if (sk->sk_state == TCP_CLOSE) {
+ goto cleanup;
+ }
+
+ if (__mptcp_check_fallback(msk)) {
+ goto update_state;
+ } else if (mptcp_close_state(sk)) {
+ pr_debug("Sending DATA_FIN sk=%p", sk);
+ WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
+ WRITE_ONCE(msk->snd_data_fin_enable, 1);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+
+ mptcp_subflow_shutdown(sk, tcp_sk, SHUTDOWN_MASK);
+ }
+ }
+
+ sk_stream_wait_close(sk, timeout);
+
+update_state:
+ inet_sk_state_store(sk, TCP_CLOSE);
+
+cleanup:
+ /* be sure to always acquire the join list lock, to sync vs
+ * mptcp_finish_join().
+ */
+ spin_lock_bh(&msk->join_list_lock);
+ list_splice_tail_init(&msk->join_list, &msk->conn_list);
+ spin_unlock_bh(&msk->join_list_lock);
+ list_splice_init(&msk->conn_list, &conn_list);
+
+ __mptcp_clear_xmit(sk);
+
+ release_sock(sk);
+
+ list_for_each_entry_safe(subflow, tmp, &conn_list, node) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+ __mptcp_close_ssk(sk, ssk, subflow, timeout);
+ }
+
+ mptcp_cancel_work(sk);
+
+ __skb_queue_purge(&sk->sk_receive_queue);
+
+ sk_common_release(sk);
+}
+
+static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk)
+{
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ const struct ipv6_pinfo *ssk6 = inet6_sk(ssk);
+ struct ipv6_pinfo *msk6 = inet6_sk(msk);
+
+ msk->sk_v6_daddr = ssk->sk_v6_daddr;
+ msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr;
+
+ if (msk6 && ssk6) {
+ msk6->saddr = ssk6->saddr;
+ msk6->flow_label = ssk6->flow_label;
+ }
+#endif
+
+ inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num;
+ inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport;
+ inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport;
+ inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr;
+ inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr;
+ inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr;
+}
+
+static int mptcp_disconnect(struct sock *sk, int flags)
+{
+ /* Should never be called.
+ * inet_stream_connect() calls ->disconnect, but that
+ * refers to the subflow socket, not the mptcp one.
+ */
+ WARN_ON_ONCE(1);
+ return 0;
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
+{
+ unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo);
+
+ return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
+}
+#endif
+
+struct sock *mptcp_sk_clone(const struct sock *sk,
+ const struct mptcp_options_received *mp_opt,
+ struct request_sock *req)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
+ struct mptcp_sock *msk;
+ u64 ack_seq;
+
+ if (!nsk)
+ return NULL;
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ if (nsk->sk_family == AF_INET6)
+ inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
+#endif
+
+ __mptcp_init_sock(nsk);
+
+ msk = mptcp_sk(nsk);
+ msk->local_key = subflow_req->local_key;
+ msk->token = subflow_req->token;
+ msk->subflow = NULL;
+ WRITE_ONCE(msk->fully_established, false);
+
+ msk->write_seq = subflow_req->idsn + 1;
+ atomic64_set(&msk->snd_una, msk->write_seq);
+ if (mp_opt->mp_capable) {
+ msk->can_ack = true;
+ msk->remote_key = mp_opt->sndr_key;
+ mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
+ ack_seq++;
+ WRITE_ONCE(msk->ack_seq, ack_seq);
+ }
+
+ sock_reset_flag(nsk, SOCK_RCU_FREE);
+ /* will be fully established after successful MPC subflow creation */
+ inet_sk_state_store(nsk, TCP_SYN_RECV);
+
+ security_inet_csk_clone(nsk, req);
+ bh_unlock_sock(nsk);
+
+ /* keep a single reference */
+ __sock_put(nsk);
+ return nsk;
+}
+
+void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk)
+{
+ const struct tcp_sock *tp = tcp_sk(ssk);
+
+ msk->rcvq_space.copied = 0;
+ msk->rcvq_space.rtt_us = 0;
+
+ msk->rcvq_space.time = tp->tcp_mstamp;
+
+ /* initial rcv_space offering made to peer */
+ msk->rcvq_space.space = min_t(u32, tp->rcv_wnd,
+ TCP_INIT_CWND * tp->advmss);
+ if (msk->rcvq_space.space == 0)
+ msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT;
+}
+
+static struct sock *mptcp_accept(struct sock *sk, int flags, int *err,
+ bool kern)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct socket *listener;
+ struct sock *newsk;
+
+ listener = __mptcp_nmpc_socket(msk);
+ if (WARN_ON_ONCE(!listener)) {
+ *err = -EINVAL;
+ return NULL;
+ }
+
+ pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk));
+ newsk = inet_csk_accept(listener->sk, flags, err, kern);
+ if (!newsk)
+ return NULL;
+
+ pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk));
+ if (sk_is_mptcp(newsk)) {
+ struct mptcp_subflow_context *subflow;
+ struct sock *new_mptcp_sock;
+ struct sock *ssk = newsk;
+
+ subflow = mptcp_subflow_ctx(newsk);
+ new_mptcp_sock = subflow->conn;
+
+ /* is_mptcp should be false if subflow->conn is missing, see
+ * subflow_syn_recv_sock()
+ */
+ if (WARN_ON_ONCE(!new_mptcp_sock)) {
+ tcp_sk(newsk)->is_mptcp = 0;
+ goto out;
+ }
+
+ /* acquire the 2nd reference for the owning socket */
+ sock_hold(new_mptcp_sock);
+
+ local_bh_disable();
+ bh_lock_sock(new_mptcp_sock);
+ msk = mptcp_sk(new_mptcp_sock);
+ msk->first = newsk;
+
+ newsk = new_mptcp_sock;
+ mptcp_copy_inaddrs(newsk, ssk);
+ list_add(&subflow->node, &msk->conn_list);
+
+ mptcp_rcv_space_init(msk, ssk);
+ bh_unlock_sock(new_mptcp_sock);
+
+ __MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK);
+ local_bh_enable();
+ } else {
+ MPTCP_INC_STATS(sock_net(sk),
+ MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK);
+ }
+
+out:
+ newsk->sk_kern_sock = kern;
+ return newsk;
+}
+
+void mptcp_destroy_common(struct mptcp_sock *msk)
+{
+ skb_rbtree_purge(&msk->out_of_order_queue);
+ mptcp_token_destroy(msk);
+ mptcp_pm_free_anno_list(msk);
+}
+
+static void mptcp_destroy(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (msk->cached_ext)
+ __skb_ext_put(msk->cached_ext);
+
+ mptcp_destroy_common(msk);
+ sk_sockets_allocated_dec(sk);
+}
+
+static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
+ sockptr_t optval, unsigned int optlen)
+{
+ struct sock *sk = (struct sock *)msk;
+ struct socket *ssock;
+ int ret;
+
+ switch (optname) {
+ case SO_REUSEPORT:
+ case SO_REUSEADDR:
+ lock_sock(sk);
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ release_sock(sk);
+ return -EINVAL;
+ }
+
+ ret = sock_setsockopt(ssock, SOL_SOCKET, optname, optval, optlen);
+ if (ret == 0) {
+ if (optname == SO_REUSEPORT)
+ sk->sk_reuseport = ssock->sk->sk_reuseport;
+ else if (optname == SO_REUSEADDR)
+ sk->sk_reuse = ssock->sk->sk_reuse;
+ }
+ release_sock(sk);
+ return ret;
+ }
+
+ return sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname, optval, optlen);
+}
+
+static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
+ sockptr_t optval, unsigned int optlen)
+{
+ struct sock *sk = (struct sock *)msk;
+ int ret = -EOPNOTSUPP;
+ struct socket *ssock;
+
+ switch (optname) {
+ case IPV6_V6ONLY:
+ lock_sock(sk);
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ release_sock(sk);
+ return -EINVAL;
+ }
+
+ ret = tcp_setsockopt(ssock->sk, SOL_IPV6, optname, optval, optlen);
+ if (ret == 0)
+ sk->sk_ipv6only = ssock->sk->sk_ipv6only;
+
+ release_sock(sk);
+ break;
+ }
+
+ return ret;
+}
+
+static bool mptcp_unsupported(int level, int optname)
+{
+ if (level == SOL_IP) {
+ switch (optname) {
+ case IP_ADD_MEMBERSHIP:
+ case IP_ADD_SOURCE_MEMBERSHIP:
+ case IP_DROP_MEMBERSHIP:
+ case IP_DROP_SOURCE_MEMBERSHIP:
+ case IP_BLOCK_SOURCE:
+ case IP_UNBLOCK_SOURCE:
+ case MCAST_JOIN_GROUP:
+ case MCAST_LEAVE_GROUP:
+ case MCAST_JOIN_SOURCE_GROUP:
+ case MCAST_LEAVE_SOURCE_GROUP:
+ case MCAST_BLOCK_SOURCE:
+ case MCAST_UNBLOCK_SOURCE:
+ case MCAST_MSFILTER:
+ return true;
+ }
+ return false;
+ }
+ if (level == SOL_IPV6) {
+ switch (optname) {
+ case IPV6_ADDRFORM:
+ case IPV6_ADD_MEMBERSHIP:
+ case IPV6_DROP_MEMBERSHIP:
+ case IPV6_JOIN_ANYCAST:
+ case IPV6_LEAVE_ANYCAST:
+ case MCAST_JOIN_GROUP:
+ case MCAST_LEAVE_GROUP:
+ case MCAST_JOIN_SOURCE_GROUP:
+ case MCAST_LEAVE_SOURCE_GROUP:
+ case MCAST_BLOCK_SOURCE:
+ case MCAST_UNBLOCK_SOURCE:
+ case MCAST_MSFILTER:
+ return true;
+ }
+ return false;
+ }
+ return false;
+}
+
+static int mptcp_setsockopt(struct sock *sk, int level, int optname,
+ sockptr_t optval, unsigned int optlen)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct sock *ssk;
+
+ pr_debug("msk=%p", msk);
+
+ if (mptcp_unsupported(level, optname))
+ return -ENOPROTOOPT;
+
+ if (level == SOL_SOCKET)
+ return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen);
+
+ /* @@ the meaning of setsockopt() when the socket is connected and
+ * there are multiple subflows is not yet defined. It is up to the
+ * MPTCP-level socket to configure the subflows until the subflow
+ * is in TCP fallback, when TCP socket options are passed through
+ * to the one remaining subflow.
+ */
+ lock_sock(sk);
+ ssk = __mptcp_tcp_fallback(msk);
+ release_sock(sk);
+ if (ssk)
+ return tcp_setsockopt(ssk, level, optname, optval, optlen);
+
+ if (level == SOL_IPV6)
+ return mptcp_setsockopt_v6(msk, optname, optval, optlen);
+
+ return -EOPNOTSUPP;
+}
+
+static int mptcp_getsockopt(struct sock *sk, int level, int optname,
+ char __user *optval, int __user *option)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct sock *ssk;
+
+ pr_debug("msk=%p", msk);
+
+ /* @@ the meaning of setsockopt() when the socket is connected and
+ * there are multiple subflows is not yet defined. It is up to the
+ * MPTCP-level socket to configure the subflows until the subflow
+ * is in TCP fallback, when socket options are passed through
+ * to the one remaining subflow.
+ */
+ lock_sock(sk);
+ ssk = __mptcp_tcp_fallback(msk);
+ release_sock(sk);
+ if (ssk)
+ return tcp_getsockopt(ssk, level, optname, optval, option);
+
+ return -EOPNOTSUPP;
+}
+
+#define MPTCP_DEFERRED_ALL (TCPF_DELACK_TIMER_DEFERRED | \
+ TCPF_WRITE_TIMER_DEFERRED)
+
+/* this is very alike tcp_release_cb() but we must handle differently a
+ * different set of events
+ */
+static void mptcp_release_cb(struct sock *sk)
+{
+ unsigned long flags, nflags;
+
+ do {
+ flags = sk->sk_tsq_flags;
+ if (!(flags & MPTCP_DEFERRED_ALL))
+ return;
+ nflags = flags & ~MPTCP_DEFERRED_ALL;
+ } while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags);
+
+ sock_release_ownership(sk);
+
+ if (flags & TCPF_DELACK_TIMER_DEFERRED) {
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct sock *ssk;
+
+ ssk = mptcp_subflow_recv_lookup(msk);
+ if (!ssk || !schedule_work(&msk->work))
+ __sock_put(sk);
+ }
+
+ if (flags & TCPF_WRITE_TIMER_DEFERRED) {
+ mptcp_retransmit_handler(sk);
+ __sock_put(sk);
+ }
+}
+
+static int mptcp_hash(struct sock *sk)
+{
+ /* should never be called,
+ * we hash the TCP subflows not the master socket
+ */
+ WARN_ON_ONCE(1);
+ return 0;
+}
+
+static void mptcp_unhash(struct sock *sk)
+{
+ /* called from sk_common_release(), but nothing to do here */
+}
+
+static int mptcp_get_port(struct sock *sk, unsigned short snum)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct socket *ssock;
+
+ ssock = __mptcp_nmpc_socket(msk);
+ pr_debug("msk=%p, subflow=%p", msk, ssock);
+ if (WARN_ON_ONCE(!ssock))
+ return -EINVAL;
+
+ return inet_csk_get_port(ssock->sk, snum);
+}
+
+void mptcp_finish_connect(struct sock *ssk)
+{
+ struct mptcp_subflow_context *subflow;
+ struct mptcp_sock *msk;
+ struct sock *sk;
+ u64 ack_seq;
+
+ subflow = mptcp_subflow_ctx(ssk);
+ sk = subflow->conn;
+ msk = mptcp_sk(sk);
+
+ pr_debug("msk=%p, token=%u", sk, subflow->token);
+
+ mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
+ ack_seq++;
+ subflow->map_seq = ack_seq;
+ subflow->map_subflow_seq = 1;
+
+ /* the socket is not connected yet, no msk/subflow ops can access/race
+ * accessing the field below
+ */
+ WRITE_ONCE(msk->remote_key, subflow->remote_key);
+ WRITE_ONCE(msk->local_key, subflow->local_key);
+ WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
+ WRITE_ONCE(msk->ack_seq, ack_seq);
+ WRITE_ONCE(msk->can_ack, 1);
+ atomic64_set(&msk->snd_una, msk->write_seq);
+
+ mptcp_pm_new_connection(msk, 0);
+
+ mptcp_rcv_space_init(msk, ssk);
+}
+
+static void mptcp_sock_graft(struct sock *sk, struct socket *parent)
+{
+ write_lock_bh(&sk->sk_callback_lock);
+ rcu_assign_pointer(sk->sk_wq, &parent->wq);
+ sk_set_socket(sk, parent);
+ sk->sk_uid = SOCK_INODE(parent)->i_uid;
+ write_unlock_bh(&sk->sk_callback_lock);
+}
+
+bool mptcp_finish_join(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+ struct sock *parent = (void *)msk;
+ struct socket *parent_sock;
+ bool ret;
+
+ pr_debug("msk=%p, subflow=%p", msk, subflow);
+
+ /* mptcp socket already closing? */
+ if (!mptcp_is_fully_established(parent))
+ return false;
+
+ if (!msk->pm.server_side)
+ return true;
+
+ if (!mptcp_pm_allow_new_subflow(msk))
+ return false;
+
+ /* active connections are already on conn_list, and we can't acquire
+ * msk lock here.
+ * use the join list lock as synchronization point and double-check
+ * msk status to avoid racing with mptcp_close()
+ */
+ spin_lock_bh(&msk->join_list_lock);
+ ret = inet_sk_state_load(parent) == TCP_ESTABLISHED;
+ if (ret && !WARN_ON_ONCE(!list_empty(&subflow->node)))
+ list_add_tail(&subflow->node, &msk->join_list);
+ spin_unlock_bh(&msk->join_list_lock);
+ if (!ret)
+ return false;
+
+ /* attach to msk socket only after we are sure he will deal with us
+ * at close time
+ */
+ parent_sock = READ_ONCE(parent->sk_socket);
+ if (parent_sock && !sk->sk_socket)
+ mptcp_sock_graft(sk, parent_sock);
+ subflow->map_seq = READ_ONCE(msk->ack_seq);
+ return true;
+}
+
+static bool mptcp_memory_free(const struct sock *sk, int wake)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ return wake ? test_bit(MPTCP_SEND_SPACE, &msk->flags) : true;
+}
+
+static struct proto mptcp_prot = {
+ .name = "MPTCP",
+ .owner = THIS_MODULE,
+ .init = mptcp_init_sock,
+ .disconnect = mptcp_disconnect,
+ .close = mptcp_close,
+ .accept = mptcp_accept,
+ .setsockopt = mptcp_setsockopt,
+ .getsockopt = mptcp_getsockopt,
+ .shutdown = tcp_shutdown,
+ .destroy = mptcp_destroy,
+ .sendmsg = mptcp_sendmsg,
+ .recvmsg = mptcp_recvmsg,
+ .release_cb = mptcp_release_cb,
+ .hash = mptcp_hash,
+ .unhash = mptcp_unhash,
+ .get_port = mptcp_get_port,
+ .sockets_allocated = &mptcp_sockets_allocated,
+ .memory_allocated = &tcp_memory_allocated,
+ .memory_pressure = &tcp_memory_pressure,
+ .stream_memory_free = mptcp_memory_free,
+ .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
+ .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem),
+ .sysctl_mem = sysctl_tcp_mem,
+ .obj_size = sizeof(struct mptcp_sock),
+ .slab_flags = SLAB_TYPESAFE_BY_RCU,
+ .no_autobind = true,
+};
+
+static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
+{
+ struct mptcp_sock *msk = mptcp_sk(sock->sk);
+ struct socket *ssock;
+ int err;
+
+ lock_sock(sock->sk);
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ err = -EINVAL;
+ goto unlock;
+ }
+
+ err = ssock->ops->bind(ssock, uaddr, addr_len);
+ if (!err)
+ mptcp_copy_inaddrs(sock->sk, ssock->sk);
+
+unlock:
+ release_sock(sock->sk);
+ return err;
+}
+
+static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
+ struct mptcp_subflow_context *subflow)
+{
+ subflow->request_mptcp = 0;
+ __mptcp_do_fallback(msk);
+}
+
+static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
+ int addr_len, int flags)
+{
+ struct mptcp_sock *msk = mptcp_sk(sock->sk);
+ struct mptcp_subflow_context *subflow;
+ struct socket *ssock;
+ int err;
+
+ lock_sock(sock->sk);
+ if (sock->state != SS_UNCONNECTED && msk->subflow) {
+ /* pending connection or invalid state, let existing subflow
+ * cope with that
+ */
+ ssock = msk->subflow;
+ goto do_connect;
+ }
+
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ err = -EINVAL;
+ goto unlock;
+ }
+
+ mptcp_token_destroy(msk);
+ inet_sk_state_store(sock->sk, TCP_SYN_SENT);
+ subflow = mptcp_subflow_ctx(ssock->sk);
+#ifdef CONFIG_TCP_MD5SIG
+ /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
+ * TCP option space.
+ */
+ if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
+ mptcp_subflow_early_fallback(msk, subflow);
+#endif
+ if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk))
+ mptcp_subflow_early_fallback(msk, subflow);
+
+do_connect:
+ err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
+ sock->state = ssock->state;
+
+ /* on successful connect, the msk state will be moved to established by
+ * subflow_finish_connect()
+ */
+ if (!err || err == -EINPROGRESS)
+ mptcp_copy_inaddrs(sock->sk, ssock->sk);
+ else
+ inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
+
+unlock:
+ release_sock(sock->sk);
+ return err;
+}
+
+static int mptcp_listen(struct socket *sock, int backlog)
+{
+ struct mptcp_sock *msk = mptcp_sk(sock->sk);
+ struct socket *ssock;
+ int err;
+
+ pr_debug("msk=%p", msk);
+
+ lock_sock(sock->sk);
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock) {
+ err = -EINVAL;
+ goto unlock;
+ }
+
+ mptcp_token_destroy(msk);
+ inet_sk_state_store(sock->sk, TCP_LISTEN);
+ sock_set_flag(sock->sk, SOCK_RCU_FREE);
+
+ err = ssock->ops->listen(ssock, backlog);
+ inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
+ if (!err)
+ mptcp_copy_inaddrs(sock->sk, ssock->sk);
+
+unlock:
+ release_sock(sock->sk);
+ return err;
+}
+
+static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
+ int flags, bool kern)
+{
+ struct mptcp_sock *msk = mptcp_sk(sock->sk);
+ struct socket *ssock;
+ int err;
+
+ pr_debug("msk=%p", msk);
+
+ lock_sock(sock->sk);
+ if (sock->sk->sk_state != TCP_LISTEN)
+ goto unlock_fail;
+
+ ssock = __mptcp_nmpc_socket(msk);
+ if (!ssock)
+ goto unlock_fail;
+
+ clear_bit(MPTCP_DATA_READY, &msk->flags);
+ sock_hold(ssock->sk);
+ release_sock(sock->sk);
+
+ err = ssock->ops->accept(sock, newsock, flags, kern);
+ if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) {
+ struct mptcp_sock *msk = mptcp_sk(newsock->sk);
+ struct mptcp_subflow_context *subflow;
+
+ /* set ssk->sk_socket of accept()ed flows to mptcp socket.
+ * This is needed so NOSPACE flag can be set from tcp stack.
+ */
+ __mptcp_flush_join_list(msk);
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ if (!ssk->sk_socket)
+ mptcp_sock_graft(ssk, newsock);
+ }
+ }
+
+ if (inet_csk_listen_poll(ssock->sk))
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+ sock_put(ssock->sk);
+ return err;
+
+unlock_fail:
+ release_sock(sock->sk);
+ return -EINVAL;
+}
+
+static __poll_t mptcp_check_readable(struct mptcp_sock *msk)
+{
+ return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM :
+ 0;
+}
+
+static __poll_t mptcp_poll(struct file *file, struct socket *sock,
+ struct poll_table_struct *wait)
+{
+ struct sock *sk = sock->sk;
+ struct mptcp_sock *msk;
+ __poll_t mask = 0;
+ int state;
+
+ msk = mptcp_sk(sk);
+ sock_poll_wait(file, sock, wait);
+
+ state = inet_sk_state_load(sk);
+ pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags);
+ if (state == TCP_LISTEN)
+ return mptcp_check_readable(msk);
+
+ if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) {
+ mask |= mptcp_check_readable(msk);
+ if (test_bit(MPTCP_SEND_SPACE, &msk->flags))
+ mask |= EPOLLOUT | EPOLLWRNORM;
+ }
+ if (sk->sk_shutdown & RCV_SHUTDOWN)
+ mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
+
+ return mask;
+}
+
+static int mptcp_shutdown(struct socket *sock, int how)
+{
+ struct mptcp_sock *msk = mptcp_sk(sock->sk);
+ struct mptcp_subflow_context *subflow;
+ int ret = 0;
+
+ pr_debug("sk=%p, how=%d", msk, how);
+
+ lock_sock(sock->sk);
+
+ how++;
+ if ((how & ~SHUTDOWN_MASK) || !how) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
+ if (sock->state == SS_CONNECTING) {
+ if ((1 << sock->sk->sk_state) &
+ (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))
+ sock->state = SS_DISCONNECTING;
+ else
+ sock->state = SS_CONNECTED;
+ }
+
+ /* If we've already sent a FIN, or it's a closed state, skip this. */
+ if (__mptcp_check_fallback(msk)) {
+ if (how == SHUT_WR || how == SHUT_RDWR)
+ inet_sk_state_store(sock->sk, TCP_FIN_WAIT1);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+
+ mptcp_subflow_shutdown(sock->sk, tcp_sk, how);
+ }
+ } else if ((how & SEND_SHUTDOWN) &&
+ ((1 << sock->sk->sk_state) &
+ (TCPF_ESTABLISHED | TCPF_SYN_SENT |
+ TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) &&
+ mptcp_close_state(sock->sk)) {
+ __mptcp_flush_join_list(msk);
+
+ WRITE_ONCE(msk->write_seq, msk->write_seq + 1);
+ WRITE_ONCE(msk->snd_data_fin_enable, 1);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow);
+
+ mptcp_subflow_shutdown(sock->sk, tcp_sk, how);
+ }
+ }
+
+ /* Wake up anyone sleeping in poll. */
+ sock->sk->sk_state_change(sock->sk);
+
+out_unlock:
+ release_sock(sock->sk);
+
+ return ret;
+}
+
+static const struct proto_ops mptcp_stream_ops = {
+ .family = PF_INET,
+ .owner = THIS_MODULE,
+ .release = inet_release,
+ .bind = mptcp_bind,
+ .connect = mptcp_stream_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = mptcp_stream_accept,
+ .getname = inet_getname,
+ .poll = mptcp_poll,
+ .ioctl = inet_ioctl,
+ .gettstamp = sock_gettstamp,
+ .listen = mptcp_listen,
+ .shutdown = mptcp_shutdown,
+ .setsockopt = sock_common_setsockopt,
+ .getsockopt = sock_common_getsockopt,
+ .sendmsg = inet_sendmsg,
+ .recvmsg = inet_recvmsg,
+ .mmap = sock_no_mmap,
+ .sendpage = inet_sendpage,
+};
+
+static struct inet_protosw mptcp_protosw = {
+ .type = SOCK_STREAM,
+ .protocol = IPPROTO_MPTCP,
+ .prot = &mptcp_prot,
+ .ops = &mptcp_stream_ops,
+ .flags = INET_PROTOSW_ICSK,
+};
+
+void __init mptcp_proto_init(void)
+{
+ mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo;
+
+ if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL))
+ panic("Failed to allocate MPTCP pcpu counter\n");
+
+ mptcp_subflow_init();
+ mptcp_pm_init();
+ mptcp_token_init();
+
+ if (proto_register(&mptcp_prot, 1) != 0)
+ panic("Failed to register MPTCP proto.\n");
+
+ inet_register_protosw(&mptcp_protosw);
+
+ BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb));
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static const struct proto_ops mptcp_v6_stream_ops = {
+ .family = PF_INET6,
+ .owner = THIS_MODULE,
+ .release = inet6_release,
+ .bind = mptcp_bind,
+ .connect = mptcp_stream_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = mptcp_stream_accept,
+ .getname = inet6_getname,
+ .poll = mptcp_poll,
+ .ioctl = inet6_ioctl,
+ .gettstamp = sock_gettstamp,
+ .listen = mptcp_listen,
+ .shutdown = mptcp_shutdown,
+ .setsockopt = sock_common_setsockopt,
+ .getsockopt = sock_common_getsockopt,
+ .sendmsg = inet6_sendmsg,
+ .recvmsg = inet6_recvmsg,
+ .mmap = sock_no_mmap,
+ .sendpage = inet_sendpage,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = inet6_compat_ioctl,
+#endif
+};
+
+static struct proto mptcp_v6_prot;
+
+static struct inet_protosw mptcp_v6_protosw = {
+ .type = SOCK_STREAM,
+ .protocol = IPPROTO_MPTCP,
+ .prot = &mptcp_v6_prot,
+ .ops = &mptcp_v6_stream_ops,
+ .flags = INET_PROTOSW_ICSK,
+};
+
+int __init mptcp_proto_v6_init(void)
+{
+ int err;
+
+ mptcp_v6_prot = mptcp_prot;
+ strcpy(mptcp_v6_prot.name, "MPTCPv6");
+ mptcp_v6_prot.slab = NULL;
+ mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
+
+ err = proto_register(&mptcp_v6_prot, 1);
+ if (err)
+ return err;
+
+ err = inet6_register_protosw(&mptcp_v6_protosw);
+ if (err)
+ proto_unregister(&mptcp_v6_prot);
+
+ return err;
+}
+#endif
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
new file mode 100644
index 000000000..3e5af8397
--- /dev/null
+++ b/net/mptcp/protocol.h
@@ -0,0 +1,568 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Multipath TCP
+ *
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ */
+
+#ifndef __MPTCP_PROTOCOL_H
+#define __MPTCP_PROTOCOL_H
+
+#include <linux/random.h>
+#include <net/tcp.h>
+#include <net/inet_connection_sock.h>
+
+#define MPTCP_SUPPORTED_VERSION 1
+
+/* MPTCP option bits */
+#define OPTION_MPTCP_MPC_SYN BIT(0)
+#define OPTION_MPTCP_MPC_SYNACK BIT(1)
+#define OPTION_MPTCP_MPC_ACK BIT(2)
+#define OPTION_MPTCP_MPJ_SYN BIT(3)
+#define OPTION_MPTCP_MPJ_SYNACK BIT(4)
+#define OPTION_MPTCP_MPJ_ACK BIT(5)
+#define OPTION_MPTCP_ADD_ADDR BIT(6)
+#define OPTION_MPTCP_ADD_ADDR6 BIT(7)
+#define OPTION_MPTCP_RM_ADDR BIT(8)
+
+/* MPTCP option subtypes */
+#define MPTCPOPT_MP_CAPABLE 0
+#define MPTCPOPT_MP_JOIN 1
+#define MPTCPOPT_DSS 2
+#define MPTCPOPT_ADD_ADDR 3
+#define MPTCPOPT_RM_ADDR 4
+#define MPTCPOPT_MP_PRIO 5
+#define MPTCPOPT_MP_FAIL 6
+#define MPTCPOPT_MP_FASTCLOSE 7
+
+/* MPTCP suboption lengths */
+#define TCPOLEN_MPTCP_MPC_SYN 4
+#define TCPOLEN_MPTCP_MPC_SYNACK 12
+#define TCPOLEN_MPTCP_MPC_ACK 20
+#define TCPOLEN_MPTCP_MPC_ACK_DATA 22
+#define TCPOLEN_MPTCP_MPJ_SYN 12
+#define TCPOLEN_MPTCP_MPJ_SYNACK 16
+#define TCPOLEN_MPTCP_MPJ_ACK 24
+#define TCPOLEN_MPTCP_DSS_BASE 4
+#define TCPOLEN_MPTCP_DSS_ACK32 4
+#define TCPOLEN_MPTCP_DSS_ACK64 8
+#define TCPOLEN_MPTCP_DSS_MAP32 10
+#define TCPOLEN_MPTCP_DSS_MAP64 14
+#define TCPOLEN_MPTCP_DSS_CHECKSUM 2
+#define TCPOLEN_MPTCP_ADD_ADDR 16
+#define TCPOLEN_MPTCP_ADD_ADDR_PORT 18
+#define TCPOLEN_MPTCP_ADD_ADDR_BASE 8
+#define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT 10
+#define TCPOLEN_MPTCP_ADD_ADDR6 28
+#define TCPOLEN_MPTCP_ADD_ADDR6_PORT 30
+#define TCPOLEN_MPTCP_ADD_ADDR6_BASE 20
+#define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT 22
+#define TCPOLEN_MPTCP_PORT_LEN 2
+#define TCPOLEN_MPTCP_RM_ADDR_BASE 4
+
+/* MPTCP MP_JOIN flags */
+#define MPTCPOPT_BACKUP BIT(0)
+#define MPTCPOPT_HMAC_LEN 20
+#define MPTCPOPT_THMAC_LEN 8
+
+/* MPTCP MP_CAPABLE flags */
+#define MPTCP_VERSION_MASK (0x0F)
+#define MPTCP_CAP_CHECKSUM_REQD BIT(7)
+#define MPTCP_CAP_EXTENSIBILITY BIT(6)
+#define MPTCP_CAP_HMAC_SHA256 BIT(0)
+#define MPTCP_CAP_FLAG_MASK (0x3F)
+
+/* MPTCP DSS flags */
+#define MPTCP_DSS_DATA_FIN BIT(4)
+#define MPTCP_DSS_DSN64 BIT(3)
+#define MPTCP_DSS_HAS_MAP BIT(2)
+#define MPTCP_DSS_ACK64 BIT(1)
+#define MPTCP_DSS_HAS_ACK BIT(0)
+#define MPTCP_DSS_FLAG_MASK (0x1F)
+
+/* MPTCP ADD_ADDR flags */
+#define MPTCP_ADDR_ECHO BIT(0)
+#define MPTCP_ADDR_IPVERSION_4 4
+#define MPTCP_ADDR_IPVERSION_6 6
+
+/* MPTCP socket flags */
+#define MPTCP_DATA_READY 0
+#define MPTCP_SEND_SPACE 1
+#define MPTCP_WORK_RTX 2
+#define MPTCP_WORK_EOF 3
+#define MPTCP_FALLBACK_DONE 4
+#define MPTCP_WORK_CLOSE_SUBFLOW 5
+
+struct mptcp_options_received {
+ u64 sndr_key;
+ u64 rcvr_key;
+ u64 data_ack;
+ u64 data_seq;
+ u32 subflow_seq;
+ u16 data_len;
+ u16 mp_capable : 1,
+ mp_join : 1,
+ dss : 1,
+ add_addr : 1,
+ rm_addr : 1,
+ family : 4,
+ echo : 1,
+ backup : 1;
+ u32 token;
+ u32 nonce;
+ u64 thmac;
+ u8 hmac[20];
+ u8 join_id;
+ u8 use_map:1,
+ dsn64:1,
+ data_fin:1,
+ use_ack:1,
+ ack64:1,
+ mpc_map:1,
+ __unused:2;
+ u8 addr_id;
+ u8 rm_id;
+ union {
+ struct in_addr addr;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ struct in6_addr addr6;
+#endif
+ };
+ u64 ahmac;
+ u16 port;
+};
+
+static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
+{
+ return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
+ ((nib & 0xF) << 8) | field);
+}
+
+struct mptcp_addr_info {
+ sa_family_t family;
+ __be16 port;
+ u8 id;
+ u8 flags;
+ int ifindex;
+ union {
+ struct in_addr addr;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ struct in6_addr addr6;
+#endif
+ };
+};
+
+enum mptcp_pm_status {
+ MPTCP_PM_ADD_ADDR_RECEIVED,
+ MPTCP_PM_RM_ADDR_RECEIVED,
+ MPTCP_PM_ESTABLISHED,
+ MPTCP_PM_SUBFLOW_ESTABLISHED,
+};
+
+struct mptcp_pm_data {
+ struct mptcp_addr_info local;
+ struct mptcp_addr_info remote;
+ struct list_head anno_list;
+
+ spinlock_t lock; /*protects the whole PM data */
+
+ bool add_addr_signal;
+ bool rm_addr_signal;
+ bool server_side;
+ bool work_pending;
+ bool accept_addr;
+ bool accept_subflow;
+ bool add_addr_echo;
+ u8 add_addr_signaled;
+ u8 add_addr_accepted;
+ u8 local_addr_used;
+ u8 subflows;
+ u8 add_addr_signal_max;
+ u8 add_addr_accept_max;
+ u8 local_addr_max;
+ u8 subflows_max;
+ u8 status;
+ u8 rm_id;
+};
+
+struct mptcp_data_frag {
+ struct list_head list;
+ u64 data_seq;
+ int data_len;
+ int offset;
+ int overhead;
+ struct page *page;
+};
+
+/* MPTCP connection sock */
+struct mptcp_sock {
+ /* inet_connection_sock must be the first member */
+ struct inet_connection_sock sk;
+ u64 local_key;
+ u64 remote_key;
+ u64 write_seq;
+ u64 ack_seq;
+ u64 rcv_data_fin_seq;
+ struct sock *last_snd;
+ int snd_burst;
+ atomic64_t snd_una;
+ unsigned long timer_ival;
+ u32 token;
+ unsigned long flags;
+ bool can_ack;
+ bool fully_established;
+ bool rcv_data_fin;
+ bool snd_data_fin_enable;
+ bool use_64bit_ack; /* Set when we received a 64-bit DSN */
+ spinlock_t join_list_lock;
+ struct work_struct work;
+ struct sk_buff *ooo_last_skb;
+ struct rb_root out_of_order_queue;
+ struct list_head conn_list;
+ struct list_head rtx_queue;
+ struct list_head join_list;
+ struct skb_ext *cached_ext; /* for the next sendmsg */
+ struct socket *subflow; /* outgoing connect/listener/!mp_capable */
+ struct sock *first;
+ struct mptcp_pm_data pm;
+ struct {
+ u32 space; /* bytes copied in last measurement window */
+ u32 copied; /* bytes copied in this measurement window */
+ u64 time; /* start time of measurement window */
+ u64 rtt_us; /* last maximum rtt of subflows */
+ } rcvq_space;
+};
+
+#define mptcp_for_each_subflow(__msk, __subflow) \
+ list_for_each_entry(__subflow, &((__msk)->conn_list), node)
+
+static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
+{
+ return (struct mptcp_sock *)sk;
+}
+
+static inline struct mptcp_data_frag *mptcp_rtx_tail(const struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ if (list_empty(&msk->rtx_queue))
+ return NULL;
+
+ return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
+}
+
+static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
+}
+
+struct mptcp_subflow_request_sock {
+ struct tcp_request_sock sk;
+ u16 mp_capable : 1,
+ mp_join : 1,
+ backup : 1;
+ u8 local_id;
+ u8 remote_id;
+ u64 local_key;
+ u64 idsn;
+ u32 token;
+ u32 ssn_offset;
+ u64 thmac;
+ u32 local_nonce;
+ u32 remote_nonce;
+ struct mptcp_sock *msk;
+ struct hlist_nulls_node token_node;
+};
+
+static inline struct mptcp_subflow_request_sock *
+mptcp_subflow_rsk(const struct request_sock *rsk)
+{
+ return (struct mptcp_subflow_request_sock *)rsk;
+}
+
+enum mptcp_data_avail {
+ MPTCP_SUBFLOW_NODATA,
+ MPTCP_SUBFLOW_DATA_AVAIL,
+ MPTCP_SUBFLOW_OOO_DATA
+};
+
+/* MPTCP subflow context */
+struct mptcp_subflow_context {
+ struct list_head node;/* conn_list of subflows */
+ u64 local_key;
+ u64 remote_key;
+ u64 idsn;
+ u64 map_seq;
+ u32 snd_isn;
+ u32 token;
+ u32 rel_write_seq;
+ u32 map_subflow_seq;
+ u32 ssn_offset;
+ u32 map_data_len;
+ u32 request_mptcp : 1, /* send MP_CAPABLE */
+ request_join : 1, /* send MP_JOIN */
+ request_bkup : 1,
+ mp_capable : 1, /* remote is MPTCP capable */
+ mp_join : 1, /* remote is JOINing */
+ fully_established : 1, /* path validated */
+ pm_notified : 1, /* PM hook called for established status */
+ conn_finished : 1,
+ map_valid : 1,
+ mpc_map : 1,
+ backup : 1,
+ rx_eof : 1,
+ can_ack : 1; /* only after processing the remote a key */
+ enum mptcp_data_avail data_avail;
+ u32 remote_nonce;
+ u64 thmac;
+ u32 local_nonce;
+ u32 remote_token;
+ u8 hmac[MPTCPOPT_HMAC_LEN];
+ u8 local_id;
+ u8 remote_id;
+
+ struct sock *tcp_sock; /* tcp sk backpointer */
+ struct sock *conn; /* parent mptcp_sock */
+ const struct inet_connection_sock_af_ops *icsk_af_ops;
+ void (*tcp_data_ready)(struct sock *sk);
+ void (*tcp_state_change)(struct sock *sk);
+ void (*tcp_write_space)(struct sock *sk);
+
+ struct rcu_head rcu;
+};
+
+static inline struct mptcp_subflow_context *
+mptcp_subflow_ctx(const struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ /* Use RCU on icsk_ulp_data only for sock diag code */
+ return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
+}
+
+static inline struct sock *
+mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
+{
+ return subflow->tcp_sock;
+}
+
+static inline u64
+mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
+{
+ return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
+ subflow->ssn_offset -
+ subflow->map_subflow_seq;
+}
+
+static inline u64
+mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
+{
+ return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
+}
+
+int mptcp_is_enabled(struct net *net);
+void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
+ struct mptcp_options_received *mp_opt);
+bool mptcp_subflow_data_available(struct sock *sk);
+void __init mptcp_subflow_init(void);
+void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
+void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
+ struct mptcp_subflow_context *subflow,
+ long timeout);
+void mptcp_subflow_reset(struct sock *ssk);
+
+/* called with sk socket lock held */
+int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
+ const struct mptcp_addr_info *remote);
+int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
+
+static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
+ struct mptcp_subflow_context *ctx)
+{
+ sk->sk_data_ready = ctx->tcp_data_ready;
+ sk->sk_state_change = ctx->tcp_state_change;
+ sk->sk_write_space = ctx->tcp_write_space;
+
+ inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
+}
+
+void __init mptcp_proto_init(void);
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+int __init mptcp_proto_v6_init(void);
+#endif
+
+struct sock *mptcp_sk_clone(const struct sock *sk,
+ const struct mptcp_options_received *mp_opt,
+ struct request_sock *req);
+void mptcp_get_options(const struct sk_buff *skb,
+ struct mptcp_options_received *mp_opt);
+
+void mptcp_finish_connect(struct sock *sk);
+static inline bool mptcp_is_fully_established(struct sock *sk)
+{
+ return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
+ READ_ONCE(mptcp_sk(sk)->fully_established);
+}
+void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
+void mptcp_data_ready(struct sock *sk, struct sock *ssk);
+bool mptcp_finish_join(struct sock *sk);
+void mptcp_data_acked(struct sock *sk);
+void mptcp_subflow_eof(struct sock *sk);
+bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
+void mptcp_destroy_common(struct mptcp_sock *msk);
+
+void __init mptcp_token_init(void);
+static inline void mptcp_token_init_request(struct request_sock *req)
+{
+ mptcp_subflow_rsk(req)->token_node.pprev = NULL;
+}
+
+int mptcp_token_new_request(struct request_sock *req);
+void mptcp_token_destroy_request(struct request_sock *req);
+int mptcp_token_new_connect(struct sock *sk);
+void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
+ struct mptcp_sock *msk);
+bool mptcp_token_exists(u32 token);
+struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token);
+struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
+ long *s_num);
+void mptcp_token_destroy(struct mptcp_sock *msk);
+
+void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
+
+void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
+
+void __init mptcp_pm_init(void);
+void mptcp_pm_data_init(struct mptcp_sock *msk);
+void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side);
+void mptcp_pm_fully_established(struct mptcp_sock *msk);
+bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
+void mptcp_pm_connection_closed(struct mptcp_sock *msk);
+void mptcp_pm_subflow_established(struct mptcp_sock *msk,
+ struct mptcp_subflow_context *subflow);
+void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id);
+void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
+ const struct mptcp_addr_info *addr);
+void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, u8 rm_id);
+void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
+struct mptcp_pm_add_entry *
+mptcp_pm_del_add_timer(struct mptcp_sock *msk,
+ struct mptcp_addr_info *addr);
+
+int mptcp_pm_announce_addr(struct mptcp_sock *msk,
+ const struct mptcp_addr_info *addr,
+ bool echo);
+int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id);
+int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 local_id);
+
+static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
+{
+ return READ_ONCE(msk->pm.add_addr_signal);
+}
+
+static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
+{
+ return READ_ONCE(msk->pm.rm_addr_signal);
+}
+
+static inline unsigned int mptcp_add_addr_len(int family, bool echo)
+{
+ if (family == AF_INET)
+ return echo ? TCPOLEN_MPTCP_ADD_ADDR_BASE
+ : TCPOLEN_MPTCP_ADD_ADDR;
+ return echo ? TCPOLEN_MPTCP_ADD_ADDR6_BASE : TCPOLEN_MPTCP_ADD_ADDR6;
+}
+
+bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
+ struct mptcp_addr_info *saddr, bool *echo);
+bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
+ u8 *rm_id);
+int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
+
+void __init mptcp_pm_nl_init(void);
+void mptcp_pm_nl_data_init(struct mptcp_sock *msk);
+void mptcp_pm_nl_fully_established(struct mptcp_sock *msk);
+void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk);
+void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk);
+void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk);
+void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, u8 rm_id);
+int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
+
+static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb)
+{
+ return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
+}
+
+static inline bool before64(__u64 seq1, __u64 seq2)
+{
+ return (__s64)(seq1 - seq2) < 0;
+}
+
+#define after64(seq2, seq1) before64(seq1, seq2)
+
+void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
+
+static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
+{
+ return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
+}
+
+static inline bool mptcp_check_fallback(const struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+
+ return __mptcp_check_fallback(msk);
+}
+
+static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
+{
+ if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags)) {
+ pr_debug("TCP fallback already done (msk=%p)", msk);
+ return;
+ }
+ set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
+}
+
+static inline void mptcp_do_fallback(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+
+ __mptcp_do_fallback(msk);
+}
+
+#define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
+
+static inline bool subflow_simultaneous_connect(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct sock *parent = subflow->conn;
+
+ return sk->sk_state == TCP_ESTABLISHED &&
+ !mptcp_sk(parent)->pm.server_side &&
+ !subflow->conn_finished;
+}
+
+#ifdef CONFIG_SYN_COOKIES
+void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
+ struct sk_buff *skb);
+bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
+ struct sk_buff *skb);
+void __init mptcp_join_cookie_init(void);
+#else
+static inline void
+subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
+ struct sk_buff *skb) {}
+static inline bool
+mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
+ struct sk_buff *skb)
+{
+ return false;
+}
+
+static inline void mptcp_join_cookie_init(void) {}
+#endif
+
+#endif /* __MPTCP_PROTOCOL_H */
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
new file mode 100644
index 000000000..607519246
--- /dev/null
+++ b/net/mptcp/subflow.c
@@ -0,0 +1,1469 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ */
+
+#define pr_fmt(fmt) "MPTCP: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <crypto/algapi.h>
+#include <crypto/sha.h>
+#include <net/sock.h>
+#include <net/inet_common.h>
+#include <net/inet_hashtables.h>
+#include <net/protocol.h>
+#include <net/tcp.h>
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+#include <net/ip6_route.h>
+#endif
+#include <net/mptcp.h>
+#include <uapi/linux/mptcp.h>
+#include "protocol.h"
+#include "mib.h"
+
+static void SUBFLOW_REQ_INC_STATS(struct request_sock *req,
+ enum linux_mptcp_mib_field field)
+{
+ MPTCP_INC_STATS(sock_net(req_to_sk(req)), field);
+}
+
+static void subflow_req_destructor(struct request_sock *req)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+
+ pr_debug("subflow_req=%p", subflow_req);
+
+ if (subflow_req->msk)
+ sock_put((struct sock *)subflow_req->msk);
+
+ mptcp_token_destroy_request(req);
+}
+
+static void subflow_generate_hmac(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
+ void *hmac)
+{
+ u8 msg[8];
+
+ put_unaligned_be32(nonce1, &msg[0]);
+ put_unaligned_be32(nonce2, &msg[4]);
+
+ mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac);
+}
+
+static bool mptcp_can_accept_new_subflow(const struct mptcp_sock *msk)
+{
+ return mptcp_is_fully_established((void *)msk) &&
+ READ_ONCE(msk->pm.accept_subflow);
+}
+
+/* validate received token and create truncated hmac and nonce for SYN-ACK */
+static struct mptcp_sock *subflow_token_join_request(struct request_sock *req,
+ const struct sk_buff *skb)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ u8 hmac[SHA256_DIGEST_SIZE];
+ struct mptcp_sock *msk;
+ int local_id;
+
+ msk = mptcp_token_get_sock(sock_net(req_to_sk(req)), subflow_req->token);
+ if (!msk) {
+ SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINNOTOKEN);
+ return NULL;
+ }
+
+ local_id = mptcp_pm_get_local_id(msk, (struct sock_common *)req);
+ if (local_id < 0) {
+ sock_put((struct sock *)msk);
+ return NULL;
+ }
+ subflow_req->local_id = local_id;
+
+ get_random_bytes(&subflow_req->local_nonce, sizeof(u32));
+
+ subflow_generate_hmac(msk->local_key, msk->remote_key,
+ subflow_req->local_nonce,
+ subflow_req->remote_nonce, hmac);
+
+ subflow_req->thmac = get_unaligned_be64(hmac);
+ return msk;
+}
+
+static int __subflow_init_req(struct request_sock *req, const struct sock *sk_listener)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+
+ subflow_req->mp_capable = 0;
+ subflow_req->mp_join = 0;
+ subflow_req->msk = NULL;
+ mptcp_token_init_request(req);
+
+#ifdef CONFIG_TCP_MD5SIG
+ /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
+ * TCP option space.
+ */
+ if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info))
+ return -EINVAL;
+#endif
+
+ return 0;
+}
+
+static void subflow_init_req(struct request_sock *req,
+ const struct sock *sk_listener,
+ struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener);
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ struct mptcp_options_received mp_opt;
+ int ret;
+
+ pr_debug("subflow_req=%p, listener=%p", subflow_req, listener);
+
+ ret = __subflow_init_req(req, sk_listener);
+ if (ret)
+ return;
+
+ mptcp_get_options(skb, &mp_opt);
+
+ if (mp_opt.mp_capable) {
+ SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE);
+
+ if (mp_opt.mp_join)
+ return;
+ } else if (mp_opt.mp_join) {
+ SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNRX);
+ }
+
+ if (mp_opt.mp_capable && listener->request_mptcp) {
+ int err, retries = 4;
+
+ subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq;
+again:
+ do {
+ get_random_bytes(&subflow_req->local_key, sizeof(subflow_req->local_key));
+ } while (subflow_req->local_key == 0);
+
+ if (unlikely(req->syncookie)) {
+ mptcp_crypto_key_sha(subflow_req->local_key,
+ &subflow_req->token,
+ &subflow_req->idsn);
+ if (mptcp_token_exists(subflow_req->token)) {
+ if (retries-- > 0)
+ goto again;
+ } else {
+ subflow_req->mp_capable = 1;
+ }
+ return;
+ }
+
+ err = mptcp_token_new_request(req);
+ if (err == 0)
+ subflow_req->mp_capable = 1;
+ else if (retries-- > 0)
+ goto again;
+
+ } else if (mp_opt.mp_join && listener->request_mptcp) {
+ subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq;
+ subflow_req->mp_join = 1;
+ subflow_req->backup = mp_opt.backup;
+ subflow_req->remote_id = mp_opt.join_id;
+ subflow_req->token = mp_opt.token;
+ subflow_req->remote_nonce = mp_opt.nonce;
+ subflow_req->msk = subflow_token_join_request(req, skb);
+
+ if (unlikely(req->syncookie) && subflow_req->msk) {
+ if (mptcp_can_accept_new_subflow(subflow_req->msk))
+ subflow_init_req_cookie_join_save(subflow_req, skb);
+ }
+
+ pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token,
+ subflow_req->remote_nonce, subflow_req->msk);
+ }
+}
+
+int mptcp_subflow_init_cookie_req(struct request_sock *req,
+ const struct sock *sk_listener,
+ struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener);
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ struct mptcp_options_received mp_opt;
+ int err;
+
+ err = __subflow_init_req(req, sk_listener);
+ if (err)
+ return err;
+
+ mptcp_get_options(skb, &mp_opt);
+
+ if (mp_opt.mp_capable && mp_opt.mp_join)
+ return -EINVAL;
+
+ if (mp_opt.mp_capable && listener->request_mptcp) {
+ if (mp_opt.sndr_key == 0)
+ return -EINVAL;
+
+ subflow_req->local_key = mp_opt.rcvr_key;
+ err = mptcp_token_new_request(req);
+ if (err)
+ return err;
+
+ subflow_req->mp_capable = 1;
+ subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1;
+ } else if (mp_opt.mp_join && listener->request_mptcp) {
+ if (!mptcp_token_join_cookie_init_state(subflow_req, skb))
+ return -EINVAL;
+
+ if (mptcp_can_accept_new_subflow(subflow_req->msk))
+ subflow_req->mp_join = 1;
+
+ subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mptcp_subflow_init_cookie_req);
+
+static void subflow_v4_init_req(struct request_sock *req,
+ const struct sock *sk_listener,
+ struct sk_buff *skb)
+{
+ tcp_rsk(req)->is_mptcp = 1;
+
+ tcp_request_sock_ipv4_ops.init_req(req, sk_listener, skb);
+
+ subflow_init_req(req, sk_listener, skb);
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static void subflow_v6_init_req(struct request_sock *req,
+ const struct sock *sk_listener,
+ struct sk_buff *skb)
+{
+ tcp_rsk(req)->is_mptcp = 1;
+
+ tcp_request_sock_ipv6_ops.init_req(req, sk_listener, skb);
+
+ subflow_init_req(req, sk_listener, skb);
+}
+#endif
+
+/* validate received truncated hmac and create hmac for third ACK */
+static bool subflow_thmac_valid(struct mptcp_subflow_context *subflow)
+{
+ u8 hmac[SHA256_DIGEST_SIZE];
+ u64 thmac;
+
+ subflow_generate_hmac(subflow->remote_key, subflow->local_key,
+ subflow->remote_nonce, subflow->local_nonce,
+ hmac);
+
+ thmac = get_unaligned_be64(hmac);
+ pr_debug("subflow=%p, token=%u, thmac=%llu, subflow->thmac=%llu\n",
+ subflow, subflow->token,
+ (unsigned long long)thmac,
+ (unsigned long long)subflow->thmac);
+
+ return thmac == subflow->thmac;
+}
+
+void mptcp_subflow_reset(struct sock *ssk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct sock *sk = subflow->conn;
+
+ tcp_send_active_reset(ssk, GFP_ATOMIC);
+ tcp_done(ssk);
+ if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags) &&
+ schedule_work(&mptcp_sk(sk)->work))
+ sock_hold(sk);
+}
+
+static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_options_received mp_opt;
+ struct sock *parent = subflow->conn;
+
+ subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);
+
+ if (inet_sk_state_load(parent) == TCP_SYN_SENT) {
+ inet_sk_state_store(parent, TCP_ESTABLISHED);
+ parent->sk_state_change(parent);
+ }
+
+ /* be sure no special action on any packet other than syn-ack */
+ if (subflow->conn_finished)
+ return;
+
+ subflow->rel_write_seq = 1;
+ subflow->conn_finished = 1;
+ subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
+ pr_debug("subflow=%p synack seq=%x", subflow, subflow->ssn_offset);
+
+ mptcp_get_options(skb, &mp_opt);
+ if (subflow->request_mptcp) {
+ if (!mp_opt.mp_capable) {
+ MPTCP_INC_STATS(sock_net(sk),
+ MPTCP_MIB_MPCAPABLEACTIVEFALLBACK);
+ mptcp_do_fallback(sk);
+ pr_fallback(mptcp_sk(subflow->conn));
+ goto fallback;
+ }
+
+ subflow->mp_capable = 1;
+ subflow->can_ack = 1;
+ subflow->remote_key = mp_opt.sndr_key;
+ pr_debug("subflow=%p, remote_key=%llu", subflow,
+ subflow->remote_key);
+ mptcp_finish_connect(sk);
+ } else if (subflow->request_join) {
+ u8 hmac[SHA256_DIGEST_SIZE];
+
+ if (!mp_opt.mp_join)
+ goto do_reset;
+
+ subflow->thmac = mp_opt.thmac;
+ subflow->remote_nonce = mp_opt.nonce;
+ pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,
+ subflow->thmac, subflow->remote_nonce);
+
+ if (!subflow_thmac_valid(subflow)) {
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINACKMAC);
+ goto do_reset;
+ }
+
+ if (!mptcp_finish_join(sk))
+ goto do_reset;
+
+ subflow_generate_hmac(subflow->local_key, subflow->remote_key,
+ subflow->local_nonce,
+ subflow->remote_nonce,
+ hmac);
+ memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN);
+
+ subflow->mp_join = 1;
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX);
+ } else if (mptcp_check_fallback(sk)) {
+fallback:
+ mptcp_rcv_space_init(mptcp_sk(parent), sk);
+ }
+ return;
+
+do_reset:
+ mptcp_subflow_reset(sk);
+}
+
+static struct request_sock_ops mptcp_subflow_v4_request_sock_ops __ro_after_init;
+static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops __ro_after_init;
+
+static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+
+ pr_debug("subflow=%p", subflow);
+
+ /* Never answer to SYNs sent to broadcast or multicast */
+ if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
+ goto drop;
+
+ return tcp_conn_request(&mptcp_subflow_v4_request_sock_ops,
+ &subflow_request_sock_ipv4_ops,
+ sk, skb);
+drop:
+ tcp_listendrop(sk);
+ return 0;
+}
+
+static void subflow_v4_req_destructor(struct request_sock *req)
+{
+ subflow_req_destructor(req);
+ tcp_request_sock_ops.destructor(req);
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static struct request_sock_ops mptcp_subflow_v6_request_sock_ops __ro_after_init;
+static struct tcp_request_sock_ops subflow_request_sock_ipv6_ops __ro_after_init;
+static struct inet_connection_sock_af_ops subflow_v6_specific __ro_after_init;
+static struct inet_connection_sock_af_ops subflow_v6m_specific __ro_after_init;
+
+static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+
+ pr_debug("subflow=%p", subflow);
+
+ if (skb->protocol == htons(ETH_P_IP))
+ return subflow_v4_conn_request(sk, skb);
+
+ if (!ipv6_unicast_destination(skb))
+ goto drop;
+
+ if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) {
+ __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS);
+ return 0;
+ }
+
+ return tcp_conn_request(&mptcp_subflow_v6_request_sock_ops,
+ &subflow_request_sock_ipv6_ops, sk, skb);
+
+drop:
+ tcp_listendrop(sk);
+ return 0; /* don't send reset */
+}
+
+static void subflow_v6_req_destructor(struct request_sock *req)
+{
+ subflow_req_destructor(req);
+ tcp6_request_sock_ops.destructor(req);
+}
+#endif
+
+struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
+ struct sock *sk_listener,
+ bool attach_listener)
+{
+ if (ops->family == AF_INET)
+ ops = &mptcp_subflow_v4_request_sock_ops;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (ops->family == AF_INET6)
+ ops = &mptcp_subflow_v6_request_sock_ops;
+#endif
+
+ return inet_reqsk_alloc(ops, sk_listener, attach_listener);
+}
+EXPORT_SYMBOL(mptcp_subflow_reqsk_alloc);
+
+/* validate hmac received in third ACK */
+static bool subflow_hmac_valid(const struct request_sock *req,
+ const struct mptcp_options_received *mp_opt)
+{
+ const struct mptcp_subflow_request_sock *subflow_req;
+ u8 hmac[SHA256_DIGEST_SIZE];
+ struct mptcp_sock *msk;
+
+ subflow_req = mptcp_subflow_rsk(req);
+ msk = subflow_req->msk;
+ if (!msk)
+ return false;
+
+ subflow_generate_hmac(msk->remote_key, msk->local_key,
+ subflow_req->remote_nonce,
+ subflow_req->local_nonce, hmac);
+
+ return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN);
+}
+
+static void mptcp_sock_destruct(struct sock *sk)
+{
+ /* if new mptcp socket isn't accepted, it is free'd
+ * from the tcp listener sockets request queue, linked
+ * from req->sk. The tcp socket is released.
+ * This calls the ULP release function which will
+ * also remove the mptcp socket, via
+ * sock_put(ctx->conn).
+ *
+ * Problem is that the mptcp socket will be in
+ * ESTABLISHED state and will not have the SOCK_DEAD flag.
+ * Both result in warnings from inet_sock_destruct.
+ */
+ if ((1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
+ sk->sk_state = TCP_CLOSE;
+ WARN_ON_ONCE(sk->sk_socket);
+ sock_orphan(sk);
+ }
+
+ mptcp_destroy_common(mptcp_sk(sk));
+ inet_sock_destruct(sk);
+}
+
+static void mptcp_force_close(struct sock *sk)
+{
+ inet_sk_state_store(sk, TCP_CLOSE);
+ sk_common_release(sk);
+}
+
+static void subflow_ulp_fallback(struct sock *sk,
+ struct mptcp_subflow_context *old_ctx)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+
+ mptcp_subflow_tcp_fallback(sk, old_ctx);
+ icsk->icsk_ulp_ops = NULL;
+ rcu_assign_pointer(icsk->icsk_ulp_data, NULL);
+ tcp_sk(sk)->is_mptcp = 0;
+}
+
+static void subflow_drop_ctx(struct sock *ssk)
+{
+ struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk);
+
+ if (!ctx)
+ return;
+
+ subflow_ulp_fallback(ssk, ctx);
+ if (ctx->conn)
+ sock_put(ctx->conn);
+
+ kfree_rcu(ctx, rcu);
+}
+
+void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
+ struct mptcp_options_received *mp_opt)
+{
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+
+ subflow->remote_key = mp_opt->sndr_key;
+ subflow->fully_established = 1;
+ subflow->can_ack = 1;
+ WRITE_ONCE(msk->fully_established, true);
+}
+
+static struct sock *subflow_syn_recv_sock(const struct sock *sk,
+ struct sk_buff *skb,
+ struct request_sock *req,
+ struct dst_entry *dst,
+ struct request_sock *req_unhash,
+ bool *own_req)
+{
+ struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk);
+ struct mptcp_subflow_request_sock *subflow_req;
+ struct mptcp_options_received mp_opt;
+ bool fallback, fallback_is_fatal;
+ struct sock *new_msk = NULL;
+ struct sock *child;
+
+ pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn);
+
+ /* After child creation we must look for 'mp_capable' even when options
+ * are not parsed
+ */
+ mp_opt.mp_capable = 0;
+
+ /* hopefully temporary handling for MP_JOIN+syncookie */
+ subflow_req = mptcp_subflow_rsk(req);
+ fallback_is_fatal = tcp_rsk(req)->is_mptcp && subflow_req->mp_join;
+ fallback = !tcp_rsk(req)->is_mptcp;
+ if (fallback)
+ goto create_child;
+
+ /* if the sk is MP_CAPABLE, we try to fetch the client key */
+ if (subflow_req->mp_capable) {
+ /* we can receive and accept an in-window, out-of-order pkt,
+ * which may not carry the MP_CAPABLE opt even on mptcp enabled
+ * paths: always try to extract the peer key, and fallback
+ * for packets missing it.
+ * Even OoO DSS packets coming legitly after dropped or
+ * reordered MPC will cause fallback, but we don't have other
+ * options.
+ */
+ mptcp_get_options(skb, &mp_opt);
+ if (!mp_opt.mp_capable) {
+ fallback = true;
+ goto create_child;
+ }
+
+ new_msk = mptcp_sk_clone(listener->conn, &mp_opt, req);
+ if (!new_msk)
+ fallback = true;
+ } else if (subflow_req->mp_join) {
+ mptcp_get_options(skb, &mp_opt);
+ if (!mp_opt.mp_join || !subflow_hmac_valid(req, &mp_opt) ||
+ !mptcp_can_accept_new_subflow(subflow_req->msk)) {
+ SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);
+ fallback = true;
+ }
+ }
+
+create_child:
+ child = listener->icsk_af_ops->syn_recv_sock(sk, skb, req, dst,
+ req_unhash, own_req);
+
+ if (child && *own_req) {
+ struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child);
+
+ tcp_rsk(req)->drop_req = false;
+
+ /* we need to fallback on ctx allocation failure and on pre-reqs
+ * checking above. In the latter scenario we additionally need
+ * to reset the context to non MPTCP status.
+ */
+ if (!ctx || fallback) {
+ if (fallback_is_fatal)
+ goto dispose_child;
+
+ subflow_drop_ctx(child);
+ goto out;
+ }
+
+ if (ctx->mp_capable) {
+ /* this can't race with mptcp_close(), as the msk is
+ * not yet exposted to user-space
+ */
+ inet_sk_state_store((void *)new_msk, TCP_ESTABLISHED);
+
+ /* new mpc subflow takes ownership of the newly
+ * created mptcp socket
+ */
+ new_msk->sk_destruct = mptcp_sock_destruct;
+ mptcp_pm_new_connection(mptcp_sk(new_msk), 1);
+ mptcp_token_accept(subflow_req, mptcp_sk(new_msk));
+ ctx->conn = new_msk;
+ new_msk = NULL;
+
+ /* with OoO packets we can reach here without ingress
+ * mpc option
+ */
+ if (mp_opt.mp_capable)
+ mptcp_subflow_fully_established(ctx, &mp_opt);
+ } else if (ctx->mp_join) {
+ struct mptcp_sock *owner;
+
+ owner = subflow_req->msk;
+ if (!owner)
+ goto dispose_child;
+
+ /* move the msk reference ownership to the subflow */
+ subflow_req->msk = NULL;
+ ctx->conn = (struct sock *)owner;
+ if (!mptcp_finish_join(child))
+ goto dispose_child;
+
+ SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX);
+ tcp_rsk(req)->drop_req = true;
+ }
+ }
+
+out:
+ /* dispose of the left over mptcp master, if any */
+ if (unlikely(new_msk))
+ mptcp_force_close(new_msk);
+
+ /* check for expected invariant - should never trigger, just help
+ * catching eariler subtle bugs
+ */
+ WARN_ON_ONCE(child && *own_req && tcp_sk(child)->is_mptcp &&
+ (!mptcp_subflow_ctx(child) ||
+ !mptcp_subflow_ctx(child)->conn));
+ return child;
+
+dispose_child:
+ subflow_drop_ctx(child);
+ tcp_rsk(req)->drop_req = true;
+ inet_csk_prepare_for_destroy_sock(child);
+ tcp_done(child);
+ req->rsk_ops->send_reset(sk, skb);
+
+ /* The last child reference will be released by the caller */
+ return child;
+}
+
+static struct inet_connection_sock_af_ops subflow_specific __ro_after_init;
+
+enum mapping_status {
+ MAPPING_OK,
+ MAPPING_INVALID,
+ MAPPING_EMPTY,
+ MAPPING_DATA_FIN,
+ MAPPING_DUMMY
+};
+
+static u64 expand_seq(u64 old_seq, u16 old_data_len, u64 seq)
+{
+ if ((u32)seq == (u32)old_seq)
+ return old_seq;
+
+ /* Assume map covers data not mapped yet. */
+ return seq | ((old_seq + old_data_len + 1) & GENMASK_ULL(63, 32));
+}
+
+static void dbg_bad_map(struct mptcp_subflow_context *subflow, u32 ssn)
+{
+ pr_debug("Bad mapping: ssn=%d map_seq=%d map_data_len=%d",
+ ssn, subflow->map_subflow_seq, subflow->map_data_len);
+}
+
+static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ unsigned int skb_consumed;
+
+ skb_consumed = tcp_sk(ssk)->copied_seq - TCP_SKB_CB(skb)->seq;
+ if (WARN_ON_ONCE(skb_consumed >= skb->len))
+ return true;
+
+ return skb->len - skb_consumed <= subflow->map_data_len -
+ mptcp_subflow_get_map_offset(subflow);
+}
+
+static bool validate_mapping(struct sock *ssk, struct sk_buff *skb)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ u32 ssn = tcp_sk(ssk)->copied_seq - subflow->ssn_offset;
+
+ if (unlikely(before(ssn, subflow->map_subflow_seq))) {
+ /* Mapping covers data later in the subflow stream,
+ * currently unsupported.
+ */
+ dbg_bad_map(subflow, ssn);
+ return false;
+ }
+ if (unlikely(!before(ssn, subflow->map_subflow_seq +
+ subflow->map_data_len))) {
+ /* Mapping does covers past subflow data, invalid */
+ dbg_bad_map(subflow, ssn);
+ return false;
+ }
+ return true;
+}
+
+static enum mapping_status get_mapping_status(struct sock *ssk,
+ struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct mptcp_ext *mpext;
+ struct sk_buff *skb;
+ u16 data_len;
+ u64 map_seq;
+
+ skb = skb_peek(&ssk->sk_receive_queue);
+ if (!skb)
+ return MAPPING_EMPTY;
+
+ if (mptcp_check_fallback(ssk))
+ return MAPPING_DUMMY;
+
+ mpext = mptcp_get_ext(skb);
+ if (!mpext || !mpext->use_map) {
+ if (!subflow->map_valid && !skb->len) {
+ /* the TCP stack deliver 0 len FIN pkt to the receive
+ * queue, that is the only 0len pkts ever expected here,
+ * and we can admit no mapping only for 0 len pkts
+ */
+ if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN))
+ WARN_ONCE(1, "0len seq %d:%d flags %x",
+ TCP_SKB_CB(skb)->seq,
+ TCP_SKB_CB(skb)->end_seq,
+ TCP_SKB_CB(skb)->tcp_flags);
+ sk_eat_skb(ssk, skb);
+ return MAPPING_EMPTY;
+ }
+
+ if (!subflow->map_valid)
+ return MAPPING_INVALID;
+
+ goto validate_seq;
+ }
+
+ pr_debug("seq=%llu is64=%d ssn=%u data_len=%u data_fin=%d",
+ mpext->data_seq, mpext->dsn64, mpext->subflow_seq,
+ mpext->data_len, mpext->data_fin);
+
+ data_len = mpext->data_len;
+ if (data_len == 0) {
+ MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX);
+ return MAPPING_INVALID;
+ }
+
+ if (mpext->data_fin == 1) {
+ if (data_len == 1) {
+ bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq,
+ mpext->dsn64);
+ pr_debug("DATA_FIN with no payload seq=%llu", mpext->data_seq);
+ if (subflow->map_valid) {
+ /* A DATA_FIN might arrive in a DSS
+ * option before the previous mapping
+ * has been fully consumed. Continue
+ * handling the existing mapping.
+ */
+ skb_ext_del(skb, SKB_EXT_MPTCP);
+ return MAPPING_OK;
+ } else {
+ if (updated && schedule_work(&msk->work))
+ sock_hold((struct sock *)msk);
+
+ return MAPPING_DATA_FIN;
+ }
+ } else {
+ u64 data_fin_seq = mpext->data_seq + data_len - 1;
+
+ /* If mpext->data_seq is a 32-bit value, data_fin_seq
+ * must also be limited to 32 bits.
+ */
+ if (!mpext->dsn64)
+ data_fin_seq &= GENMASK_ULL(31, 0);
+
+ mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64);
+ pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d",
+ data_fin_seq, mpext->dsn64);
+ }
+
+ /* Adjust for DATA_FIN using 1 byte of sequence space */
+ data_len--;
+ }
+
+ if (!mpext->dsn64) {
+ map_seq = expand_seq(subflow->map_seq, subflow->map_data_len,
+ mpext->data_seq);
+ pr_debug("expanded seq=%llu", subflow->map_seq);
+ } else {
+ map_seq = mpext->data_seq;
+ }
+ WRITE_ONCE(mptcp_sk(subflow->conn)->use_64bit_ack, !!mpext->dsn64);
+
+ if (subflow->map_valid) {
+ /* Allow replacing only with an identical map */
+ if (subflow->map_seq == map_seq &&
+ subflow->map_subflow_seq == mpext->subflow_seq &&
+ subflow->map_data_len == data_len) {
+ skb_ext_del(skb, SKB_EXT_MPTCP);
+ return MAPPING_OK;
+ }
+
+ /* If this skb data are fully covered by the current mapping,
+ * the new map would need caching, which is not supported
+ */
+ if (skb_is_fully_mapped(ssk, skb)) {
+ MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSNOMATCH);
+ return MAPPING_INVALID;
+ }
+
+ /* will validate the next map after consuming the current one */
+ return MAPPING_OK;
+ }
+
+ subflow->map_seq = map_seq;
+ subflow->map_subflow_seq = mpext->subflow_seq;
+ subflow->map_data_len = data_len;
+ subflow->map_valid = 1;
+ subflow->mpc_map = mpext->mpc_map;
+ pr_debug("new map seq=%llu subflow_seq=%u data_len=%u",
+ subflow->map_seq, subflow->map_subflow_seq,
+ subflow->map_data_len);
+
+validate_seq:
+ /* we revalidate valid mapping on new skb, because we must ensure
+ * the current skb is completely covered by the available mapping
+ */
+ if (!validate_mapping(ssk, skb))
+ return MAPPING_INVALID;
+
+ skb_ext_del(skb, SKB_EXT_MPTCP);
+ return MAPPING_OK;
+}
+
+static void mptcp_subflow_discard_data(struct sock *ssk, struct sk_buff *skb,
+ u64 limit)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ bool fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
+ u32 incr;
+
+ incr = limit >= skb->len ? skb->len + fin : limit;
+
+ pr_debug("discarding=%d len=%d seq=%d", incr, skb->len,
+ subflow->map_subflow_seq);
+ MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DUPDATA);
+ tcp_sk(ssk)->copied_seq += incr;
+ if (!before(tcp_sk(ssk)->copied_seq, TCP_SKB_CB(skb)->end_seq))
+ sk_eat_skb(ssk, skb);
+ if (mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len)
+ subflow->map_valid = 0;
+ if (incr)
+ tcp_cleanup_rbuf(ssk, incr);
+}
+
+static bool subflow_check_data_avail(struct sock *ssk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ enum mapping_status status;
+ struct mptcp_sock *msk;
+ struct sk_buff *skb;
+
+ pr_debug("msk=%p ssk=%p data_avail=%d skb=%p", subflow->conn, ssk,
+ subflow->data_avail, skb_peek(&ssk->sk_receive_queue));
+ if (!skb_peek(&ssk->sk_receive_queue))
+ subflow->data_avail = 0;
+ if (subflow->data_avail)
+ return true;
+
+ msk = mptcp_sk(subflow->conn);
+ for (;;) {
+ u64 ack_seq;
+ u64 old_ack;
+
+ status = get_mapping_status(ssk, msk);
+ pr_debug("msk=%p ssk=%p status=%d", msk, ssk, status);
+ if (status == MAPPING_INVALID) {
+ ssk->sk_err = EBADMSG;
+ goto fatal;
+ }
+ if (status == MAPPING_DUMMY) {
+ __mptcp_do_fallback(msk);
+ skb = skb_peek(&ssk->sk_receive_queue);
+ subflow->map_valid = 1;
+ subflow->map_seq = READ_ONCE(msk->ack_seq);
+ subflow->map_data_len = skb->len;
+ subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq -
+ subflow->ssn_offset;
+ subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
+ return true;
+ }
+
+ if (status != MAPPING_OK)
+ return false;
+
+ skb = skb_peek(&ssk->sk_receive_queue);
+ if (WARN_ON_ONCE(!skb))
+ return false;
+
+ /* if msk lacks the remote key, this subflow must provide an
+ * MP_CAPABLE-based mapping
+ */
+ if (unlikely(!READ_ONCE(msk->can_ack))) {
+ if (!subflow->mpc_map) {
+ ssk->sk_err = EBADMSG;
+ goto fatal;
+ }
+ WRITE_ONCE(msk->remote_key, subflow->remote_key);
+ WRITE_ONCE(msk->ack_seq, subflow->map_seq);
+ WRITE_ONCE(msk->can_ack, true);
+ }
+
+ old_ack = READ_ONCE(msk->ack_seq);
+ ack_seq = mptcp_subflow_get_mapped_dsn(subflow);
+ pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack,
+ ack_seq);
+ if (ack_seq == old_ack) {
+ subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
+ break;
+ } else if (after64(ack_seq, old_ack)) {
+ subflow->data_avail = MPTCP_SUBFLOW_OOO_DATA;
+ break;
+ }
+
+ /* only accept in-sequence mapping. Old values are spurious
+ * retransmission
+ */
+ mptcp_subflow_discard_data(ssk, skb, old_ack - ack_seq);
+ }
+ return true;
+
+fatal:
+ /* fatal protocol error, close the socket */
+ /* This barrier is coupled with smp_rmb() in tcp_poll() */
+ smp_wmb();
+ ssk->sk_error_report(ssk);
+ tcp_set_state(ssk, TCP_CLOSE);
+ tcp_send_active_reset(ssk, GFP_ATOMIC);
+ subflow->data_avail = 0;
+ return false;
+}
+
+bool mptcp_subflow_data_available(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+
+ /* check if current mapping is still valid */
+ if (subflow->map_valid &&
+ mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) {
+ subflow->map_valid = 0;
+ subflow->data_avail = 0;
+
+ pr_debug("Done with mapping: seq=%u data_len=%u",
+ subflow->map_subflow_seq,
+ subflow->map_data_len);
+ }
+
+ return subflow_check_data_avail(sk);
+}
+
+/* If ssk has an mptcp parent socket, use the mptcp rcvbuf occupancy,
+ * not the ssk one.
+ *
+ * In mptcp, rwin is about the mptcp-level connection data.
+ *
+ * Data that is still on the ssk rx queue can thus be ignored,
+ * as far as mptcp peer is concerened that data is still inflight.
+ * DSS ACK is updated when skb is moved to the mptcp rx queue.
+ */
+void mptcp_space(const struct sock *ssk, int *space, int *full_space)
+{
+ const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ const struct sock *sk = subflow->conn;
+
+ *space = tcp_space(sk);
+ *full_space = tcp_full_space(sk);
+}
+
+static void subflow_data_ready(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ u16 state = 1 << inet_sk_state_load(sk);
+ struct sock *parent = subflow->conn;
+ struct mptcp_sock *msk;
+
+ msk = mptcp_sk(parent);
+ if (state & TCPF_LISTEN) {
+ /* MPJ subflow are removed from accept queue before reaching here,
+ * avoid stray wakeups
+ */
+ if (reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue))
+ return;
+
+ set_bit(MPTCP_DATA_READY, &msk->flags);
+ parent->sk_data_ready(parent);
+ return;
+ }
+
+ WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable &&
+ !subflow->mp_join && !(state & TCPF_CLOSE));
+
+ if (mptcp_subflow_data_available(sk))
+ mptcp_data_ready(parent, sk);
+}
+
+static void subflow_write_space(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct sock *parent = subflow->conn;
+
+ if (!sk_stream_is_writeable(sk))
+ return;
+
+ if (sk_stream_is_writeable(parent)) {
+ set_bit(MPTCP_SEND_SPACE, &mptcp_sk(parent)->flags);
+ smp_mb__after_atomic();
+ /* set SEND_SPACE before sk_stream_write_space clears NOSPACE */
+ sk_stream_write_space(parent);
+ }
+}
+
+static const struct inet_connection_sock_af_ops *
+subflow_default_af_ops(struct sock *sk)
+{
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ if (sk->sk_family == AF_INET6)
+ return &subflow_v6_specific;
+#endif
+ return &subflow_specific;
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+void mptcpv6_handle_mapped(struct sock *sk, bool mapped)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ const struct inet_connection_sock_af_ops *target;
+
+ target = mapped ? &subflow_v6m_specific : subflow_default_af_ops(sk);
+
+ pr_debug("subflow=%p family=%d ops=%p target=%p mapped=%d",
+ subflow, sk->sk_family, icsk->icsk_af_ops, target, mapped);
+
+ if (likely(icsk->icsk_af_ops == target))
+ return;
+
+ subflow->icsk_af_ops = icsk->icsk_af_ops;
+ icsk->icsk_af_ops = target;
+}
+#endif
+
+static void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
+ struct sockaddr_storage *addr)
+{
+ memset(addr, 0, sizeof(*addr));
+ addr->ss_family = info->family;
+ if (addr->ss_family == AF_INET) {
+ struct sockaddr_in *in_addr = (struct sockaddr_in *)addr;
+
+ in_addr->sin_addr = info->addr;
+ in_addr->sin_port = info->port;
+ }
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (addr->ss_family == AF_INET6) {
+ struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)addr;
+
+ in6_addr->sin6_addr = info->addr6;
+ in6_addr->sin6_port = info->port;
+ }
+#endif
+}
+
+int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
+ const struct mptcp_addr_info *remote)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct mptcp_subflow_context *subflow;
+ struct sockaddr_storage addr;
+ int remote_id = remote->id;
+ int local_id = loc->id;
+ struct socket *sf;
+ struct sock *ssk;
+ u32 remote_token;
+ int addrlen;
+ int err;
+
+ if (!mptcp_is_fully_established(sk))
+ return -ENOTCONN;
+
+ err = mptcp_subflow_create_socket(sk, &sf);
+ if (err)
+ return err;
+
+ ssk = sf->sk;
+ subflow = mptcp_subflow_ctx(ssk);
+ do {
+ get_random_bytes(&subflow->local_nonce, sizeof(u32));
+ } while (!subflow->local_nonce);
+
+ if (!local_id) {
+ err = mptcp_pm_get_local_id(msk, (struct sock_common *)ssk);
+ if (err < 0)
+ goto failed;
+
+ local_id = err;
+ }
+
+ subflow->remote_key = msk->remote_key;
+ subflow->local_key = msk->local_key;
+ subflow->token = msk->token;
+ mptcp_info2sockaddr(loc, &addr);
+
+ addrlen = sizeof(struct sockaddr_in);
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ if (loc->family == AF_INET6)
+ addrlen = sizeof(struct sockaddr_in6);
+#endif
+ ssk->sk_bound_dev_if = loc->ifindex;
+ err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen);
+ if (err)
+ goto failed;
+
+ mptcp_crypto_key_sha(subflow->remote_key, &remote_token, NULL);
+ pr_debug("msk=%p remote_token=%u local_id=%d remote_id=%d", msk,
+ remote_token, local_id, remote_id);
+ subflow->remote_token = remote_token;
+ subflow->local_id = local_id;
+ subflow->remote_id = remote_id;
+ subflow->request_join = 1;
+ subflow->request_bkup = !!(loc->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
+ mptcp_info2sockaddr(remote, &addr);
+
+ err = kernel_connect(sf, (struct sockaddr *)&addr, addrlen, O_NONBLOCK);
+ if (err && err != -EINPROGRESS)
+ goto failed;
+
+ spin_lock_bh(&msk->join_list_lock);
+ list_add_tail(&subflow->node, &msk->join_list);
+ spin_unlock_bh(&msk->join_list_lock);
+
+ return err;
+
+failed:
+ sock_release(sf);
+ return err;
+}
+
+int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock)
+{
+ struct mptcp_subflow_context *subflow;
+ struct net *net = sock_net(sk);
+ struct socket *sf;
+ int err;
+
+ /* un-accepted server sockets can reach here - on bad configuration
+ * bail early to avoid greater trouble later
+ */
+ if (unlikely(!sk->sk_socket))
+ return -EINVAL;
+
+ err = sock_create_kern(net, sk->sk_family, SOCK_STREAM, IPPROTO_TCP,
+ &sf);
+ if (err)
+ return err;
+
+ lock_sock(sf->sk);
+
+ /* kernel sockets do not by default acquire net ref, but TCP timer
+ * needs it.
+ */
+ sf->sk->sk_net_refcnt = 1;
+ get_net(net);
+#ifdef CONFIG_PROC_FS
+ this_cpu_add(*net->core.sock_inuse, 1);
+#endif
+ err = tcp_set_ulp(sf->sk, "mptcp");
+ release_sock(sf->sk);
+
+ if (err) {
+ sock_release(sf);
+ return err;
+ }
+
+ /* the newly created socket really belongs to the owning MPTCP master
+ * socket, even if for additional subflows the allocation is performed
+ * by a kernel workqueue. Adjust inode references, so that the
+ * procfs/diag interaces really show this one belonging to the correct
+ * user.
+ */
+ SOCK_INODE(sf)->i_ino = SOCK_INODE(sk->sk_socket)->i_ino;
+ SOCK_INODE(sf)->i_uid = SOCK_INODE(sk->sk_socket)->i_uid;
+ SOCK_INODE(sf)->i_gid = SOCK_INODE(sk->sk_socket)->i_gid;
+
+ subflow = mptcp_subflow_ctx(sf->sk);
+ pr_debug("subflow=%p", subflow);
+
+ *new_sock = sf;
+ sock_hold(sk);
+ subflow->conn = sk;
+
+ return 0;
+}
+
+static struct mptcp_subflow_context *subflow_create_ctx(struct sock *sk,
+ gfp_t priority)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct mptcp_subflow_context *ctx;
+
+ ctx = kzalloc(sizeof(*ctx), priority);
+ if (!ctx)
+ return NULL;
+
+ rcu_assign_pointer(icsk->icsk_ulp_data, ctx);
+ INIT_LIST_HEAD(&ctx->node);
+
+ pr_debug("subflow=%p", ctx);
+
+ ctx->tcp_sock = sk;
+
+ return ctx;
+}
+
+static void __subflow_state_change(struct sock *sk)
+{
+ struct socket_wq *wq;
+
+ rcu_read_lock();
+ wq = rcu_dereference(sk->sk_wq);
+ if (skwq_has_sleeper(wq))
+ wake_up_interruptible_all(&wq->wait);
+ rcu_read_unlock();
+}
+
+static bool subflow_is_done(const struct sock *sk)
+{
+ return sk->sk_shutdown & RCV_SHUTDOWN || sk->sk_state == TCP_CLOSE;
+}
+
+static void subflow_state_change(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct sock *parent = subflow->conn;
+
+ __subflow_state_change(sk);
+
+ if (subflow_simultaneous_connect(sk)) {
+ mptcp_do_fallback(sk);
+ mptcp_rcv_space_init(mptcp_sk(parent), sk);
+ pr_fallback(mptcp_sk(parent));
+ subflow->conn_finished = 1;
+ if (inet_sk_state_load(parent) == TCP_SYN_SENT) {
+ inet_sk_state_store(parent, TCP_ESTABLISHED);
+ parent->sk_state_change(parent);
+ }
+ }
+
+ /* as recvmsg() does not acquire the subflow socket for ssk selection
+ * a fin packet carrying a DSS can be unnoticed if we don't trigger
+ * the data available machinery here.
+ */
+ if (mptcp_subflow_data_available(sk))
+ mptcp_data_ready(parent, sk);
+
+ if (__mptcp_check_fallback(mptcp_sk(parent)) &&
+ !(parent->sk_shutdown & RCV_SHUTDOWN) &&
+ !subflow->rx_eof && subflow_is_done(sk)) {
+ subflow->rx_eof = 1;
+ mptcp_subflow_eof(parent);
+ }
+}
+
+static int subflow_ulp_init(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct mptcp_subflow_context *ctx;
+ struct tcp_sock *tp = tcp_sk(sk);
+ int err = 0;
+
+ /* disallow attaching ULP to a socket unless it has been
+ * created with sock_create_kern()
+ */
+ if (!sk->sk_kern_sock) {
+ err = -EOPNOTSUPP;
+ goto out;
+ }
+
+ ctx = subflow_create_ctx(sk, GFP_KERNEL);
+ if (!ctx) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ pr_debug("subflow=%p, family=%d", ctx, sk->sk_family);
+
+ tp->is_mptcp = 1;
+ ctx->icsk_af_ops = icsk->icsk_af_ops;
+ icsk->icsk_af_ops = subflow_default_af_ops(sk);
+ ctx->tcp_data_ready = sk->sk_data_ready;
+ ctx->tcp_state_change = sk->sk_state_change;
+ ctx->tcp_write_space = sk->sk_write_space;
+ sk->sk_data_ready = subflow_data_ready;
+ sk->sk_write_space = subflow_write_space;
+ sk->sk_state_change = subflow_state_change;
+out:
+ return err;
+}
+
+static void subflow_ulp_release(struct sock *sk)
+{
+ struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(sk);
+
+ if (!ctx)
+ return;
+
+ if (ctx->conn)
+ sock_put(ctx->conn);
+
+ kfree_rcu(ctx, rcu);
+}
+
+static void subflow_ulp_clone(const struct request_sock *req,
+ struct sock *newsk,
+ const gfp_t priority)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ struct mptcp_subflow_context *old_ctx = mptcp_subflow_ctx(newsk);
+ struct mptcp_subflow_context *new_ctx;
+
+ if (!tcp_rsk(req)->is_mptcp ||
+ (!subflow_req->mp_capable && !subflow_req->mp_join)) {
+ subflow_ulp_fallback(newsk, old_ctx);
+ return;
+ }
+
+ new_ctx = subflow_create_ctx(newsk, priority);
+ if (!new_ctx) {
+ subflow_ulp_fallback(newsk, old_ctx);
+ return;
+ }
+
+ new_ctx->conn_finished = 1;
+ new_ctx->icsk_af_ops = old_ctx->icsk_af_ops;
+ new_ctx->tcp_data_ready = old_ctx->tcp_data_ready;
+ new_ctx->tcp_state_change = old_ctx->tcp_state_change;
+ new_ctx->tcp_write_space = old_ctx->tcp_write_space;
+ new_ctx->rel_write_seq = 1;
+ new_ctx->tcp_sock = newsk;
+
+ if (subflow_req->mp_capable) {
+ /* see comments in subflow_syn_recv_sock(), MPTCP connection
+ * is fully established only after we receive the remote key
+ */
+ new_ctx->mp_capable = 1;
+ new_ctx->local_key = subflow_req->local_key;
+ new_ctx->token = subflow_req->token;
+ new_ctx->ssn_offset = subflow_req->ssn_offset;
+ new_ctx->idsn = subflow_req->idsn;
+ } else if (subflow_req->mp_join) {
+ new_ctx->ssn_offset = subflow_req->ssn_offset;
+ new_ctx->mp_join = 1;
+ new_ctx->fully_established = 1;
+ new_ctx->backup = subflow_req->backup;
+ new_ctx->local_id = subflow_req->local_id;
+ new_ctx->remote_id = subflow_req->remote_id;
+ new_ctx->token = subflow_req->token;
+ new_ctx->thmac = subflow_req->thmac;
+ }
+}
+
+static struct tcp_ulp_ops subflow_ulp_ops __read_mostly = {
+ .name = "mptcp",
+ .owner = THIS_MODULE,
+ .init = subflow_ulp_init,
+ .release = subflow_ulp_release,
+ .clone = subflow_ulp_clone,
+};
+
+static int subflow_ops_init(struct request_sock_ops *subflow_ops)
+{
+ subflow_ops->obj_size = sizeof(struct mptcp_subflow_request_sock);
+
+ subflow_ops->slab = kmem_cache_create(subflow_ops->slab_name,
+ subflow_ops->obj_size, 0,
+ SLAB_ACCOUNT |
+ SLAB_TYPESAFE_BY_RCU,
+ NULL);
+ if (!subflow_ops->slab)
+ return -ENOMEM;
+
+ return 0;
+}
+
+void __init mptcp_subflow_init(void)
+{
+ mptcp_subflow_v4_request_sock_ops = tcp_request_sock_ops;
+ mptcp_subflow_v4_request_sock_ops.slab_name = "request_sock_subflow_v4";
+ mptcp_subflow_v4_request_sock_ops.destructor = subflow_v4_req_destructor;
+
+ if (subflow_ops_init(&mptcp_subflow_v4_request_sock_ops) != 0)
+ panic("MPTCP: failed to init subflow v4 request sock ops\n");
+
+ subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops;
+ subflow_request_sock_ipv4_ops.init_req = subflow_v4_init_req;
+
+ subflow_specific = ipv4_specific;
+ subflow_specific.conn_request = subflow_v4_conn_request;
+ subflow_specific.syn_recv_sock = subflow_syn_recv_sock;
+ subflow_specific.sk_rx_dst_set = subflow_finish_connect;
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ /* In struct mptcp_subflow_request_sock, we assume the TCP request sock
+ * structures for v4 and v6 have the same size. It should not changed in
+ * the future but better to make sure to be warned if it is no longer
+ * the case.
+ */
+ BUILD_BUG_ON(sizeof(struct tcp_request_sock) != sizeof(struct tcp6_request_sock));
+
+ mptcp_subflow_v6_request_sock_ops = tcp6_request_sock_ops;
+ mptcp_subflow_v6_request_sock_ops.slab_name = "request_sock_subflow_v6";
+ mptcp_subflow_v6_request_sock_ops.destructor = subflow_v6_req_destructor;
+
+ if (subflow_ops_init(&mptcp_subflow_v6_request_sock_ops) != 0)
+ panic("MPTCP: failed to init subflow v6 request sock ops\n");
+
+ subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops;
+ subflow_request_sock_ipv6_ops.init_req = subflow_v6_init_req;
+
+ subflow_v6_specific = ipv6_specific;
+ subflow_v6_specific.conn_request = subflow_v6_conn_request;
+ subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock;
+ subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect;
+
+ subflow_v6m_specific = subflow_v6_specific;
+ subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit;
+ subflow_v6m_specific.send_check = ipv4_specific.send_check;
+ subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len;
+ subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced;
+ subflow_v6m_specific.net_frag_header_len = 0;
+#endif
+
+ mptcp_diag_subflow_init(&subflow_ulp_ops);
+
+ if (tcp_register_ulp(&subflow_ulp_ops) != 0)
+ panic("MPTCP: failed to register subflows to ULP\n");
+}
diff --git a/net/mptcp/syncookies.c b/net/mptcp/syncookies.c
new file mode 100644
index 000000000..7f2252634
--- /dev/null
+++ b/net/mptcp/syncookies.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/skbuff.h>
+
+#include "protocol.h"
+
+/* Syncookies do not work for JOIN requests.
+ *
+ * Unlike MP_CAPABLE, where the ACK cookie contains the needed MPTCP
+ * options to reconstruct the initial syn state, MP_JOIN does not contain
+ * the token to obtain the mptcp socket nor the server-generated nonce
+ * that was used in the cookie SYN/ACK response.
+ *
+ * Keep a small best effort state table to store the syn/synack data,
+ * indexed by skb hash.
+ *
+ * A MP_JOIN SYN packet handled by syn cookies is only stored if the 32bit
+ * token matches a known mptcp connection that can still accept more subflows.
+ *
+ * There is no timeout handling -- state is only re-constructed
+ * when the TCP ACK passed the cookie validation check.
+ */
+
+struct join_entry {
+ u32 token;
+ u32 remote_nonce;
+ u32 local_nonce;
+ u8 join_id;
+ u8 local_id;
+ u8 backup;
+ u8 valid;
+};
+
+#define COOKIE_JOIN_SLOTS 1024
+
+static struct join_entry join_entries[COOKIE_JOIN_SLOTS] __cacheline_aligned_in_smp;
+static spinlock_t join_entry_locks[COOKIE_JOIN_SLOTS] __cacheline_aligned_in_smp;
+
+static u32 mptcp_join_entry_hash(struct sk_buff *skb, struct net *net)
+{
+ static u32 mptcp_join_hash_secret __read_mostly;
+ struct tcphdr *th = tcp_hdr(skb);
+ u32 seq, i;
+
+ net_get_random_once(&mptcp_join_hash_secret,
+ sizeof(mptcp_join_hash_secret));
+
+ if (th->syn)
+ seq = TCP_SKB_CB(skb)->seq;
+ else
+ seq = TCP_SKB_CB(skb)->seq - 1;
+
+ i = jhash_3words(seq, net_hash_mix(net),
+ (__force __u32)th->source << 16 | (__force __u32)th->dest,
+ mptcp_join_hash_secret);
+
+ return i % ARRAY_SIZE(join_entries);
+}
+
+static void mptcp_join_store_state(struct join_entry *entry,
+ const struct mptcp_subflow_request_sock *subflow_req)
+{
+ entry->token = subflow_req->token;
+ entry->remote_nonce = subflow_req->remote_nonce;
+ entry->local_nonce = subflow_req->local_nonce;
+ entry->backup = subflow_req->backup;
+ entry->join_id = subflow_req->remote_id;
+ entry->local_id = subflow_req->local_id;
+ entry->valid = 1;
+}
+
+void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
+ struct sk_buff *skb)
+{
+ struct net *net = read_pnet(&subflow_req->sk.req.ireq_net);
+ u32 i = mptcp_join_entry_hash(skb, net);
+
+ /* No use in waiting if other cpu is already using this slot --
+ * would overwrite the data that got stored.
+ */
+ spin_lock_bh(&join_entry_locks[i]);
+ mptcp_join_store_state(&join_entries[i], subflow_req);
+ spin_unlock_bh(&join_entry_locks[i]);
+}
+
+/* Called for a cookie-ack with MP_JOIN option present.
+ * Look up the saved state based on skb hash & check token matches msk
+ * in same netns.
+ *
+ * Caller will check msk can still accept another subflow. The hmac
+ * present in the cookie ACK mptcp option space will be checked later.
+ */
+bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
+ struct sk_buff *skb)
+{
+ struct net *net = read_pnet(&subflow_req->sk.req.ireq_net);
+ u32 i = mptcp_join_entry_hash(skb, net);
+ struct mptcp_sock *msk;
+ struct join_entry *e;
+
+ e = &join_entries[i];
+
+ spin_lock_bh(&join_entry_locks[i]);
+
+ if (e->valid == 0) {
+ spin_unlock_bh(&join_entry_locks[i]);
+ return false;
+ }
+
+ e->valid = 0;
+
+ msk = mptcp_token_get_sock(net, e->token);
+ if (!msk) {
+ spin_unlock_bh(&join_entry_locks[i]);
+ return false;
+ }
+
+ subflow_req->remote_nonce = e->remote_nonce;
+ subflow_req->local_nonce = e->local_nonce;
+ subflow_req->backup = e->backup;
+ subflow_req->remote_id = e->join_id;
+ subflow_req->token = e->token;
+ subflow_req->msk = msk;
+ spin_unlock_bh(&join_entry_locks[i]);
+ return true;
+}
+
+void __init mptcp_join_cookie_init(void)
+{
+ int i;
+
+ for (i = 0; i < COOKIE_JOIN_SLOTS; i++)
+ spin_lock_init(&join_entry_locks[i]);
+}
diff --git a/net/mptcp/token.c b/net/mptcp/token.c
new file mode 100644
index 000000000..f0d656bf2
--- /dev/null
+++ b/net/mptcp/token.c
@@ -0,0 +1,416 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP token management
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ *
+ * Note: This code is based on mptcp_ctrl.c from multipath-tcp.org,
+ * authored by:
+ *
+ * Sébastien Barré <sebastien.barre@uclouvain.be>
+ * Christoph Paasch <christoph.paasch@uclouvain.be>
+ * Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
+ * Gregory Detal <gregory.detal@uclouvain.be>
+ * Fabien Duchêne <fabien.duchene@uclouvain.be>
+ * Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
+ * Lavkesh Lahngir <lavkesh51@gmail.com>
+ * Andreas Ripke <ripke@neclab.eu>
+ * Vlad Dogaru <vlad.dogaru@intel.com>
+ * Octavian Purdila <octavian.purdila@intel.com>
+ * John Ronan <jronan@tssg.org>
+ * Catalin Nicutar <catalin.nicutar@gmail.com>
+ * Brandon Heller <brandonh@stanford.edu>
+ */
+
+#define pr_fmt(fmt) "MPTCP: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/memblock.h>
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <net/sock.h>
+#include <net/inet_common.h>
+#include <net/protocol.h>
+#include <net/mptcp.h>
+#include "protocol.h"
+
+#define TOKEN_MAX_RETRIES 4
+#define TOKEN_MAX_CHAIN_LEN 4
+
+struct token_bucket {
+ spinlock_t lock;
+ int chain_len;
+ struct hlist_nulls_head req_chain;
+ struct hlist_nulls_head msk_chain;
+};
+
+static struct token_bucket *token_hash __read_mostly;
+static unsigned int token_mask __read_mostly;
+
+static struct token_bucket *token_bucket(u32 token)
+{
+ return &token_hash[token & token_mask];
+}
+
+/* called with bucket lock held */
+static struct mptcp_subflow_request_sock *
+__token_lookup_req(struct token_bucket *t, u32 token)
+{
+ struct mptcp_subflow_request_sock *req;
+ struct hlist_nulls_node *pos;
+
+ hlist_nulls_for_each_entry_rcu(req, pos, &t->req_chain, token_node)
+ if (req->token == token)
+ return req;
+ return NULL;
+}
+
+/* called with bucket lock held */
+static struct mptcp_sock *
+__token_lookup_msk(struct token_bucket *t, u32 token)
+{
+ struct hlist_nulls_node *pos;
+ struct sock *sk;
+
+ sk_nulls_for_each_rcu(sk, pos, &t->msk_chain)
+ if (mptcp_sk(sk)->token == token)
+ return mptcp_sk(sk);
+ return NULL;
+}
+
+static bool __token_bucket_busy(struct token_bucket *t, u32 token)
+{
+ return !token || t->chain_len >= TOKEN_MAX_CHAIN_LEN ||
+ __token_lookup_req(t, token) || __token_lookup_msk(t, token);
+}
+
+static void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn)
+{
+ /* we might consider a faster version that computes the key as a
+ * hash of some information available in the MPTCP socket. Use
+ * random data at the moment, as it's probably the safest option
+ * in case multiple sockets are opened in different namespaces at
+ * the same time.
+ */
+ get_random_bytes(key, sizeof(u64));
+ mptcp_crypto_key_sha(*key, token, idsn);
+}
+
+/**
+ * mptcp_token_new_request - create new key/idsn/token for subflow_request
+ * @req: the request socket
+ *
+ * This function is called when a new mptcp connection is coming in.
+ *
+ * It creates a unique token to identify the new mptcp connection,
+ * a secret local key and the initial data sequence number (idsn).
+ *
+ * Returns 0 on success.
+ */
+int mptcp_token_new_request(struct request_sock *req)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ struct token_bucket *bucket;
+ u32 token;
+
+ mptcp_crypto_key_sha(subflow_req->local_key,
+ &subflow_req->token,
+ &subflow_req->idsn);
+ pr_debug("req=%p local_key=%llu, token=%u, idsn=%llu\n",
+ req, subflow_req->local_key, subflow_req->token,
+ subflow_req->idsn);
+
+ token = subflow_req->token;
+ bucket = token_bucket(token);
+ spin_lock_bh(&bucket->lock);
+ if (__token_bucket_busy(bucket, token)) {
+ spin_unlock_bh(&bucket->lock);
+ return -EBUSY;
+ }
+
+ hlist_nulls_add_head_rcu(&subflow_req->token_node, &bucket->req_chain);
+ bucket->chain_len++;
+ spin_unlock_bh(&bucket->lock);
+ return 0;
+}
+
+/**
+ * mptcp_token_new_connect - create new key/idsn/token for subflow
+ * @sk: the socket that will initiate a connection
+ *
+ * This function is called when a new outgoing mptcp connection is
+ * initiated.
+ *
+ * It creates a unique token to identify the new mptcp connection,
+ * a secret local key and the initial data sequence number (idsn).
+ *
+ * On success, the mptcp connection can be found again using
+ * the computed token at a later time, this is needed to process
+ * join requests.
+ *
+ * returns 0 on success.
+ */
+int mptcp_token_new_connect(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+ int retries = TOKEN_MAX_RETRIES;
+ struct token_bucket *bucket;
+
+again:
+ mptcp_crypto_key_gen_sha(&subflow->local_key, &subflow->token,
+ &subflow->idsn);
+
+ bucket = token_bucket(subflow->token);
+ spin_lock_bh(&bucket->lock);
+ if (__token_bucket_busy(bucket, subflow->token)) {
+ spin_unlock_bh(&bucket->lock);
+ if (!--retries)
+ return -EBUSY;
+ goto again;
+ }
+
+ pr_debug("ssk=%p, local_key=%llu, token=%u, idsn=%llu\n",
+ sk, subflow->local_key, subflow->token, subflow->idsn);
+
+ WRITE_ONCE(msk->token, subflow->token);
+ __sk_nulls_add_node_rcu((struct sock *)msk, &bucket->msk_chain);
+ bucket->chain_len++;
+ spin_unlock_bh(&bucket->lock);
+ return 0;
+}
+
+/**
+ * mptcp_token_accept - replace a req sk with full sock in token hash
+ * @req: the request socket to be removed
+ * @msk: the just cloned socket linked to the new connection
+ *
+ * Called when a SYN packet creates a new logical connection, i.e.
+ * is not a join request.
+ */
+void mptcp_token_accept(struct mptcp_subflow_request_sock *req,
+ struct mptcp_sock *msk)
+{
+ struct mptcp_subflow_request_sock *pos;
+ struct token_bucket *bucket;
+
+ bucket = token_bucket(req->token);
+ spin_lock_bh(&bucket->lock);
+
+ /* pedantic lookup check for the moved token */
+ pos = __token_lookup_req(bucket, req->token);
+ if (!WARN_ON_ONCE(pos != req))
+ hlist_nulls_del_init_rcu(&req->token_node);
+ __sk_nulls_add_node_rcu((struct sock *)msk, &bucket->msk_chain);
+ spin_unlock_bh(&bucket->lock);
+}
+
+bool mptcp_token_exists(u32 token)
+{
+ struct hlist_nulls_node *pos;
+ struct token_bucket *bucket;
+ struct mptcp_sock *msk;
+ struct sock *sk;
+
+ rcu_read_lock();
+ bucket = token_bucket(token);
+
+again:
+ sk_nulls_for_each_rcu(sk, pos, &bucket->msk_chain) {
+ msk = mptcp_sk(sk);
+ if (READ_ONCE(msk->token) == token)
+ goto found;
+ }
+ if (get_nulls_value(pos) != (token & token_mask))
+ goto again;
+
+ rcu_read_unlock();
+ return false;
+found:
+ rcu_read_unlock();
+ return true;
+}
+
+/**
+ * mptcp_token_get_sock - retrieve mptcp connection sock using its token
+ * @net: restrict to this namespace
+ * @token: token of the mptcp connection to retrieve
+ *
+ * This function returns the mptcp connection structure with the given token.
+ * A reference count on the mptcp socket returned is taken.
+ *
+ * returns NULL if no connection with the given token value exists.
+ */
+struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token)
+{
+ struct hlist_nulls_node *pos;
+ struct token_bucket *bucket;
+ struct mptcp_sock *msk;
+ struct sock *sk;
+
+ rcu_read_lock();
+ bucket = token_bucket(token);
+
+again:
+ sk_nulls_for_each_rcu(sk, pos, &bucket->msk_chain) {
+ msk = mptcp_sk(sk);
+ if (READ_ONCE(msk->token) != token ||
+ !net_eq(sock_net(sk), net))
+ continue;
+
+ if (!refcount_inc_not_zero(&sk->sk_refcnt))
+ goto not_found;
+
+ if (READ_ONCE(msk->token) != token ||
+ !net_eq(sock_net(sk), net)) {
+ sock_put(sk);
+ goto again;
+ }
+ goto found;
+ }
+ if (get_nulls_value(pos) != (token & token_mask))
+ goto again;
+
+not_found:
+ msk = NULL;
+
+found:
+ rcu_read_unlock();
+ return msk;
+}
+EXPORT_SYMBOL_GPL(mptcp_token_get_sock);
+
+/**
+ * mptcp_token_iter_next - iterate over the token container from given pos
+ * @net: namespace to be iterated
+ * @s_slot: start slot number
+ * @s_num: start number inside the given lock
+ *
+ * This function returns the first mptcp connection structure found inside the
+ * token container starting from the specified position, or NULL.
+ *
+ * On successful iteration, the iterator is move to the next position and the
+ * the acquires a reference to the returned socket.
+ */
+struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
+ long *s_num)
+{
+ struct mptcp_sock *ret = NULL;
+ struct hlist_nulls_node *pos;
+ int slot, num = 0;
+
+ for (slot = *s_slot; slot <= token_mask; *s_num = 0, slot++) {
+ struct token_bucket *bucket = &token_hash[slot];
+ struct sock *sk;
+
+ num = 0;
+
+ if (hlist_nulls_empty(&bucket->msk_chain))
+ continue;
+
+ rcu_read_lock();
+ sk_nulls_for_each_rcu(sk, pos, &bucket->msk_chain) {
+ ++num;
+ if (!net_eq(sock_net(sk), net))
+ continue;
+
+ if (num <= *s_num)
+ continue;
+
+ if (!refcount_inc_not_zero(&sk->sk_refcnt))
+ continue;
+
+ if (!net_eq(sock_net(sk), net)) {
+ sock_put(sk);
+ continue;
+ }
+
+ ret = mptcp_sk(sk);
+ rcu_read_unlock();
+ goto out;
+ }
+ rcu_read_unlock();
+ }
+
+out:
+ *s_slot = slot;
+ *s_num = num;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(mptcp_token_iter_next);
+
+/**
+ * mptcp_token_destroy_request - remove mptcp connection/token
+ * @req: mptcp request socket dropping the token
+ *
+ * Remove the token associated to @req.
+ */
+void mptcp_token_destroy_request(struct request_sock *req)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ struct mptcp_subflow_request_sock *pos;
+ struct token_bucket *bucket;
+
+ if (hlist_nulls_unhashed(&subflow_req->token_node))
+ return;
+
+ bucket = token_bucket(subflow_req->token);
+ spin_lock_bh(&bucket->lock);
+ pos = __token_lookup_req(bucket, subflow_req->token);
+ if (!WARN_ON_ONCE(pos != subflow_req)) {
+ hlist_nulls_del_init_rcu(&pos->token_node);
+ bucket->chain_len--;
+ }
+ spin_unlock_bh(&bucket->lock);
+}
+
+/**
+ * mptcp_token_destroy - remove mptcp connection/token
+ * @msk: mptcp connection dropping the token
+ *
+ * Remove the token associated to @msk
+ */
+void mptcp_token_destroy(struct mptcp_sock *msk)
+{
+ struct token_bucket *bucket;
+ struct mptcp_sock *pos;
+
+ if (sk_unhashed((struct sock *)msk))
+ return;
+
+ bucket = token_bucket(msk->token);
+ spin_lock_bh(&bucket->lock);
+ pos = __token_lookup_msk(bucket, msk->token);
+ if (!WARN_ON_ONCE(pos != msk)) {
+ __sk_nulls_del_node_init_rcu((struct sock *)pos);
+ bucket->chain_len--;
+ }
+ spin_unlock_bh(&bucket->lock);
+}
+
+void __init mptcp_token_init(void)
+{
+ int i;
+
+ token_hash = alloc_large_system_hash("MPTCP token",
+ sizeof(struct token_bucket),
+ 0,
+ 20,/* one slot per 1MB of memory */
+ HASH_ZERO,
+ NULL,
+ &token_mask,
+ 0,
+ 64 * 1024);
+ for (i = 0; i < token_mask + 1; ++i) {
+ INIT_HLIST_NULLS_HEAD(&token_hash[i].req_chain, i);
+ INIT_HLIST_NULLS_HEAD(&token_hash[i].msk_chain, i);
+ spin_lock_init(&token_hash[i].lock);
+ }
+}
+
+#if IS_MODULE(CONFIG_MPTCP_KUNIT_TESTS)
+EXPORT_SYMBOL_GPL(mptcp_token_new_request);
+EXPORT_SYMBOL_GPL(mptcp_token_new_connect);
+EXPORT_SYMBOL_GPL(mptcp_token_accept);
+EXPORT_SYMBOL_GPL(mptcp_token_destroy_request);
+EXPORT_SYMBOL_GPL(mptcp_token_destroy);
+#endif
diff --git a/net/mptcp/token_test.c b/net/mptcp/token_test.c
new file mode 100644
index 000000000..5d984bec1
--- /dev/null
+++ b/net/mptcp/token_test.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <kunit/test.h>
+
+#include "protocol.h"
+
+static struct mptcp_subflow_request_sock *build_req_sock(struct kunit *test)
+{
+ struct mptcp_subflow_request_sock *req;
+
+ req = kunit_kzalloc(test, sizeof(struct mptcp_subflow_request_sock),
+ GFP_USER);
+ KUNIT_EXPECT_NOT_ERR_OR_NULL(test, req);
+ mptcp_token_init_request((struct request_sock *)req);
+ sock_net_set((struct sock *)req, &init_net);
+ return req;
+}
+
+static void mptcp_token_test_req_basic(struct kunit *test)
+{
+ struct mptcp_subflow_request_sock *req = build_req_sock(test);
+ struct mptcp_sock *null_msk = NULL;
+
+ KUNIT_ASSERT_EQ(test, 0,
+ mptcp_token_new_request((struct request_sock *)req));
+ KUNIT_EXPECT_NE(test, 0, (int)req->token);
+ KUNIT_EXPECT_PTR_EQ(test, null_msk, mptcp_token_get_sock(&init_net, req->token));
+
+ /* cleanup */
+ mptcp_token_destroy_request((struct request_sock *)req);
+}
+
+static struct inet_connection_sock *build_icsk(struct kunit *test)
+{
+ struct inet_connection_sock *icsk;
+
+ icsk = kunit_kzalloc(test, sizeof(struct inet_connection_sock),
+ GFP_USER);
+ KUNIT_EXPECT_NOT_ERR_OR_NULL(test, icsk);
+ return icsk;
+}
+
+static struct mptcp_subflow_context *build_ctx(struct kunit *test)
+{
+ struct mptcp_subflow_context *ctx;
+
+ ctx = kunit_kzalloc(test, sizeof(struct mptcp_subflow_context),
+ GFP_USER);
+ KUNIT_EXPECT_NOT_ERR_OR_NULL(test, ctx);
+ return ctx;
+}
+
+static struct mptcp_sock *build_msk(struct kunit *test)
+{
+ struct mptcp_sock *msk;
+
+ msk = kunit_kzalloc(test, sizeof(struct mptcp_sock), GFP_USER);
+ KUNIT_EXPECT_NOT_ERR_OR_NULL(test, msk);
+ refcount_set(&((struct sock *)msk)->sk_refcnt, 1);
+ sock_net_set((struct sock *)msk, &init_net);
+ return msk;
+}
+
+static void mptcp_token_test_msk_basic(struct kunit *test)
+{
+ struct inet_connection_sock *icsk = build_icsk(test);
+ struct mptcp_subflow_context *ctx = build_ctx(test);
+ struct mptcp_sock *msk = build_msk(test);
+ struct mptcp_sock *null_msk = NULL;
+ struct sock *sk;
+
+ rcu_assign_pointer(icsk->icsk_ulp_data, ctx);
+ ctx->conn = (struct sock *)msk;
+ sk = (struct sock *)msk;
+
+ KUNIT_ASSERT_EQ(test, 0,
+ mptcp_token_new_connect((struct sock *)icsk));
+ KUNIT_EXPECT_NE(test, 0, (int)ctx->token);
+ KUNIT_EXPECT_EQ(test, ctx->token, msk->token);
+ KUNIT_EXPECT_PTR_EQ(test, msk, mptcp_token_get_sock(&init_net, ctx->token));
+ KUNIT_EXPECT_EQ(test, 2, (int)refcount_read(&sk->sk_refcnt));
+
+ mptcp_token_destroy(msk);
+ KUNIT_EXPECT_PTR_EQ(test, null_msk, mptcp_token_get_sock(&init_net, ctx->token));
+}
+
+static void mptcp_token_test_accept(struct kunit *test)
+{
+ struct mptcp_subflow_request_sock *req = build_req_sock(test);
+ struct mptcp_sock *msk = build_msk(test);
+
+ KUNIT_ASSERT_EQ(test, 0,
+ mptcp_token_new_request((struct request_sock *)req));
+ msk->token = req->token;
+ mptcp_token_accept(req, msk);
+ KUNIT_EXPECT_PTR_EQ(test, msk, mptcp_token_get_sock(&init_net, msk->token));
+
+ /* this is now a no-op */
+ mptcp_token_destroy_request((struct request_sock *)req);
+ KUNIT_EXPECT_PTR_EQ(test, msk, mptcp_token_get_sock(&init_net, msk->token));
+
+ /* cleanup */
+ mptcp_token_destroy(msk);
+}
+
+static void mptcp_token_test_destroyed(struct kunit *test)
+{
+ struct mptcp_subflow_request_sock *req = build_req_sock(test);
+ struct mptcp_sock *msk = build_msk(test);
+ struct mptcp_sock *null_msk = NULL;
+ struct sock *sk;
+
+ sk = (struct sock *)msk;
+
+ KUNIT_ASSERT_EQ(test, 0,
+ mptcp_token_new_request((struct request_sock *)req));
+ msk->token = req->token;
+ mptcp_token_accept(req, msk);
+
+ /* simulate race on removal */
+ refcount_set(&sk->sk_refcnt, 0);
+ KUNIT_EXPECT_PTR_EQ(test, null_msk, mptcp_token_get_sock(&init_net, msk->token));
+
+ /* cleanup */
+ mptcp_token_destroy(msk);
+}
+
+static struct kunit_case mptcp_token_test_cases[] = {
+ KUNIT_CASE(mptcp_token_test_req_basic),
+ KUNIT_CASE(mptcp_token_test_msk_basic),
+ KUNIT_CASE(mptcp_token_test_accept),
+ KUNIT_CASE(mptcp_token_test_destroyed),
+ {}
+};
+
+static struct kunit_suite mptcp_token_suite = {
+ .name = "mptcp-token",
+ .test_cases = mptcp_token_test_cases,
+};
+
+kunit_test_suite(mptcp_token_suite);
+
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-26 17:16:37 +0000