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-rw-r--r--net/rxrpc/call_accept.c491
1 files changed, 491 insertions, 0 deletions
diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
new file mode 100644
index 000000000..99e10eea3
--- /dev/null
+++ b/net/rxrpc/call_accept.c
@@ -0,0 +1,491 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* incoming call handling
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/errqueue.h>
+#include <linux/udp.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/icmp.h>
+#include <linux/gfp.h>
+#include <linux/circ_buf.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include <net/ip.h>
+#include "ar-internal.h"
+
+static void rxrpc_dummy_notify(struct sock *sk, struct rxrpc_call *call,
+ unsigned long user_call_ID)
+{
+}
+
+/*
+ * Preallocate a single service call, connection and peer and, if possible,
+ * give them a user ID and attach the user's side of the ID to them.
+ */
+static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx,
+ struct rxrpc_backlog *b,
+ rxrpc_notify_rx_t notify_rx,
+ rxrpc_user_attach_call_t user_attach_call,
+ unsigned long user_call_ID, gfp_t gfp,
+ unsigned int debug_id)
+{
+ const void *here = __builtin_return_address(0);
+ struct rxrpc_call *call, *xcall;
+ struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
+ struct rb_node *parent, **pp;
+ int max, tmp;
+ unsigned int size = RXRPC_BACKLOG_MAX;
+ unsigned int head, tail, call_head, call_tail;
+
+ max = rx->sk.sk_max_ack_backlog;
+ tmp = rx->sk.sk_ack_backlog;
+ if (tmp >= max) {
+ _leave(" = -ENOBUFS [full %u]", max);
+ return -ENOBUFS;
+ }
+ max -= tmp;
+
+ /* We don't need more conns and peers than we have calls, but on the
+ * other hand, we shouldn't ever use more peers than conns or conns
+ * than calls.
+ */
+ call_head = b->call_backlog_head;
+ call_tail = READ_ONCE(b->call_backlog_tail);
+ tmp = CIRC_CNT(call_head, call_tail, size);
+ if (tmp >= max) {
+ _leave(" = -ENOBUFS [enough %u]", tmp);
+ return -ENOBUFS;
+ }
+ max = tmp + 1;
+
+ head = b->peer_backlog_head;
+ tail = READ_ONCE(b->peer_backlog_tail);
+ if (CIRC_CNT(head, tail, size) < max) {
+ struct rxrpc_peer *peer = rxrpc_alloc_peer(rx->local, gfp);
+ if (!peer)
+ return -ENOMEM;
+ b->peer_backlog[head] = peer;
+ smp_store_release(&b->peer_backlog_head,
+ (head + 1) & (size - 1));
+ }
+
+ head = b->conn_backlog_head;
+ tail = READ_ONCE(b->conn_backlog_tail);
+ if (CIRC_CNT(head, tail, size) < max) {
+ struct rxrpc_connection *conn;
+
+ conn = rxrpc_prealloc_service_connection(rxnet, gfp);
+ if (!conn)
+ return -ENOMEM;
+ b->conn_backlog[head] = conn;
+ smp_store_release(&b->conn_backlog_head,
+ (head + 1) & (size - 1));
+
+ trace_rxrpc_conn(conn->debug_id, rxrpc_conn_new_service,
+ refcount_read(&conn->ref), here);
+ }
+
+ /* Now it gets complicated, because calls get registered with the
+ * socket here, with a user ID preassigned by the user.
+ */
+ call = rxrpc_alloc_call(rx, gfp, debug_id);
+ if (!call)
+ return -ENOMEM;
+ call->flags |= (1 << RXRPC_CALL_IS_SERVICE);
+ call->state = RXRPC_CALL_SERVER_PREALLOC;
+
+ trace_rxrpc_call(call->debug_id, rxrpc_call_new_service,
+ refcount_read(&call->ref),
+ here, (const void *)user_call_ID);
+
+ write_lock(&rx->call_lock);
+
+ /* Check the user ID isn't already in use */
+ pp = &rx->calls.rb_node;
+ parent = NULL;
+ while (*pp) {
+ parent = *pp;
+ xcall = rb_entry(parent, struct rxrpc_call, sock_node);
+ if (user_call_ID < xcall->user_call_ID)
+ pp = &(*pp)->rb_left;
+ else if (user_call_ID > xcall->user_call_ID)
+ pp = &(*pp)->rb_right;
+ else
+ goto id_in_use;
+ }
+
+ call->user_call_ID = user_call_ID;
+ call->notify_rx = notify_rx;
+ if (user_attach_call) {
+ rxrpc_get_call(call, rxrpc_call_got_kernel);
+ user_attach_call(call, user_call_ID);
+ }
+
+ rxrpc_get_call(call, rxrpc_call_got_userid);
+ rb_link_node(&call->sock_node, parent, pp);
+ rb_insert_color(&call->sock_node, &rx->calls);
+ set_bit(RXRPC_CALL_HAS_USERID, &call->flags);
+
+ list_add(&call->sock_link, &rx->sock_calls);
+
+ write_unlock(&rx->call_lock);
+
+ rxnet = call->rxnet;
+ spin_lock_bh(&rxnet->call_lock);
+ list_add_tail_rcu(&call->link, &rxnet->calls);
+ spin_unlock_bh(&rxnet->call_lock);
+
+ b->call_backlog[call_head] = call;
+ smp_store_release(&b->call_backlog_head, (call_head + 1) & (size - 1));
+ _leave(" = 0 [%d -> %lx]", call->debug_id, user_call_ID);
+ return 0;
+
+id_in_use:
+ write_unlock(&rx->call_lock);
+ rxrpc_cleanup_call(call);
+ _leave(" = -EBADSLT");
+ return -EBADSLT;
+}
+
+/*
+ * Allocate the preallocation buffers for incoming service calls. These must
+ * be charged manually.
+ */
+int rxrpc_service_prealloc(struct rxrpc_sock *rx, gfp_t gfp)
+{
+ struct rxrpc_backlog *b = rx->backlog;
+
+ if (!b) {
+ b = kzalloc(sizeof(struct rxrpc_backlog), gfp);
+ if (!b)
+ return -ENOMEM;
+ rx->backlog = b;
+ }
+
+ return 0;
+}
+
+/*
+ * Discard the preallocation on a service.
+ */
+void rxrpc_discard_prealloc(struct rxrpc_sock *rx)
+{
+ struct rxrpc_backlog *b = rx->backlog;
+ struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
+ unsigned int size = RXRPC_BACKLOG_MAX, head, tail;
+
+ if (!b)
+ return;
+ rx->backlog = NULL;
+
+ /* Make sure that there aren't any incoming calls in progress before we
+ * clear the preallocation buffers.
+ */
+ spin_lock_bh(&rx->incoming_lock);
+ spin_unlock_bh(&rx->incoming_lock);
+
+ head = b->peer_backlog_head;
+ tail = b->peer_backlog_tail;
+ while (CIRC_CNT(head, tail, size) > 0) {
+ struct rxrpc_peer *peer = b->peer_backlog[tail];
+ rxrpc_put_local(peer->local);
+ kfree(peer);
+ tail = (tail + 1) & (size - 1);
+ }
+
+ head = b->conn_backlog_head;
+ tail = b->conn_backlog_tail;
+ while (CIRC_CNT(head, tail, size) > 0) {
+ struct rxrpc_connection *conn = b->conn_backlog[tail];
+ write_lock(&rxnet->conn_lock);
+ list_del(&conn->link);
+ list_del(&conn->proc_link);
+ write_unlock(&rxnet->conn_lock);
+ kfree(conn);
+ if (atomic_dec_and_test(&rxnet->nr_conns))
+ wake_up_var(&rxnet->nr_conns);
+ tail = (tail + 1) & (size - 1);
+ }
+
+ head = b->call_backlog_head;
+ tail = b->call_backlog_tail;
+ while (CIRC_CNT(head, tail, size) > 0) {
+ struct rxrpc_call *call = b->call_backlog[tail];
+ rcu_assign_pointer(call->socket, rx);
+ if (rx->discard_new_call) {
+ _debug("discard %lx", call->user_call_ID);
+ rx->discard_new_call(call, call->user_call_ID);
+ if (call->notify_rx)
+ call->notify_rx = rxrpc_dummy_notify;
+ rxrpc_put_call(call, rxrpc_call_put_kernel);
+ }
+ rxrpc_call_completed(call);
+ rxrpc_release_call(rx, call);
+ rxrpc_put_call(call, rxrpc_call_put);
+ tail = (tail + 1) & (size - 1);
+ }
+
+ kfree(b);
+}
+
+/*
+ * Ping the other end to fill our RTT cache and to retrieve the rwind
+ * and MTU parameters.
+ */
+static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb)
+{
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ ktime_t now = skb->tstamp;
+
+ if (call->peer->rtt_count < 3 ||
+ ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now))
+ rxrpc_propose_ACK(call, RXRPC_ACK_PING, sp->hdr.serial,
+ true, true,
+ rxrpc_propose_ack_ping_for_params);
+}
+
+/*
+ * Allocate a new incoming call from the prealloc pool, along with a connection
+ * and a peer as necessary.
+ */
+static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx,
+ struct rxrpc_local *local,
+ struct rxrpc_peer *peer,
+ struct rxrpc_connection *conn,
+ const struct rxrpc_security *sec,
+ struct sk_buff *skb)
+{
+ struct rxrpc_backlog *b = rx->backlog;
+ struct rxrpc_call *call;
+ unsigned short call_head, conn_head, peer_head;
+ unsigned short call_tail, conn_tail, peer_tail;
+ unsigned short call_count, conn_count;
+
+ /* #calls >= #conns >= #peers must hold true. */
+ call_head = smp_load_acquire(&b->call_backlog_head);
+ call_tail = b->call_backlog_tail;
+ call_count = CIRC_CNT(call_head, call_tail, RXRPC_BACKLOG_MAX);
+ conn_head = smp_load_acquire(&b->conn_backlog_head);
+ conn_tail = b->conn_backlog_tail;
+ conn_count = CIRC_CNT(conn_head, conn_tail, RXRPC_BACKLOG_MAX);
+ ASSERTCMP(conn_count, >=, call_count);
+ peer_head = smp_load_acquire(&b->peer_backlog_head);
+ peer_tail = b->peer_backlog_tail;
+ ASSERTCMP(CIRC_CNT(peer_head, peer_tail, RXRPC_BACKLOG_MAX), >=,
+ conn_count);
+
+ if (call_count == 0)
+ return NULL;
+
+ if (!conn) {
+ if (peer && !rxrpc_get_peer_maybe(peer))
+ peer = NULL;
+ if (!peer) {
+ peer = b->peer_backlog[peer_tail];
+ if (rxrpc_extract_addr_from_skb(&peer->srx, skb) < 0)
+ return NULL;
+ b->peer_backlog[peer_tail] = NULL;
+ smp_store_release(&b->peer_backlog_tail,
+ (peer_tail + 1) &
+ (RXRPC_BACKLOG_MAX - 1));
+
+ rxrpc_new_incoming_peer(rx, local, peer);
+ }
+
+ /* Now allocate and set up the connection */
+ conn = b->conn_backlog[conn_tail];
+ b->conn_backlog[conn_tail] = NULL;
+ smp_store_release(&b->conn_backlog_tail,
+ (conn_tail + 1) & (RXRPC_BACKLOG_MAX - 1));
+ conn->params.local = rxrpc_get_local(local);
+ conn->params.peer = peer;
+ rxrpc_see_connection(conn);
+ rxrpc_new_incoming_connection(rx, conn, sec, skb);
+ } else {
+ rxrpc_get_connection(conn);
+ }
+
+ /* And now we can allocate and set up a new call */
+ call = b->call_backlog[call_tail];
+ b->call_backlog[call_tail] = NULL;
+ smp_store_release(&b->call_backlog_tail,
+ (call_tail + 1) & (RXRPC_BACKLOG_MAX - 1));
+
+ rxrpc_see_call(call);
+ call->conn = conn;
+ call->security = conn->security;
+ call->security_ix = conn->security_ix;
+ call->peer = rxrpc_get_peer(conn->params.peer);
+ call->cong_cwnd = call->peer->cong_cwnd;
+ return call;
+}
+
+/*
+ * Set up a new incoming call. Called in BH context with the RCU read lock
+ * held.
+ *
+ * If this is for a kernel service, when we allocate the call, it will have
+ * three refs on it: (1) the kernel service, (2) the user_call_ID tree, (3) the
+ * retainer ref obtained from the backlog buffer. Prealloc calls for userspace
+ * services only have the ref from the backlog buffer. We want to pass this
+ * ref to non-BH context to dispose of.
+ *
+ * If we want to report an error, we mark the skb with the packet type and
+ * abort code and return NULL.
+ *
+ * The call is returned with the user access mutex held.
+ */
+struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local,
+ struct rxrpc_sock *rx,
+ struct sk_buff *skb)
+{
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ const struct rxrpc_security *sec = NULL;
+ struct rxrpc_connection *conn;
+ struct rxrpc_peer *peer = NULL;
+ struct rxrpc_call *call = NULL;
+
+ _enter("");
+
+ spin_lock(&rx->incoming_lock);
+ if (rx->sk.sk_state == RXRPC_SERVER_LISTEN_DISABLED ||
+ rx->sk.sk_state == RXRPC_CLOSE) {
+ trace_rxrpc_abort(0, "CLS", sp->hdr.cid, sp->hdr.callNumber,
+ sp->hdr.seq, RX_INVALID_OPERATION, ESHUTDOWN);
+ skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
+ skb->priority = RX_INVALID_OPERATION;
+ goto no_call;
+ }
+
+ /* The peer, connection and call may all have sprung into existence due
+ * to a duplicate packet being handled on another CPU in parallel, so
+ * we have to recheck the routing. However, we're now holding
+ * rx->incoming_lock, so the values should remain stable.
+ */
+ conn = rxrpc_find_connection_rcu(local, skb, &peer);
+
+ if (!conn) {
+ sec = rxrpc_get_incoming_security(rx, skb);
+ if (!sec)
+ goto no_call;
+ }
+
+ call = rxrpc_alloc_incoming_call(rx, local, peer, conn, sec, skb);
+ if (!call) {
+ skb->mark = RXRPC_SKB_MARK_REJECT_BUSY;
+ goto no_call;
+ }
+
+ trace_rxrpc_receive(call, rxrpc_receive_incoming,
+ sp->hdr.serial, sp->hdr.seq);
+
+ /* Make the call live. */
+ rxrpc_incoming_call(rx, call, skb);
+ conn = call->conn;
+
+ if (rx->notify_new_call)
+ rx->notify_new_call(&rx->sk, call, call->user_call_ID);
+
+ spin_lock(&conn->state_lock);
+ switch (conn->state) {
+ case RXRPC_CONN_SERVICE_UNSECURED:
+ conn->state = RXRPC_CONN_SERVICE_CHALLENGING;
+ set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events);
+ rxrpc_queue_conn(call->conn);
+ break;
+
+ case RXRPC_CONN_SERVICE:
+ write_lock(&call->state_lock);
+ if (call->state < RXRPC_CALL_COMPLETE)
+ call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
+ write_unlock(&call->state_lock);
+ break;
+
+ case RXRPC_CONN_REMOTELY_ABORTED:
+ rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
+ conn->abort_code, conn->error);
+ break;
+ case RXRPC_CONN_LOCALLY_ABORTED:
+ rxrpc_abort_call("CON", call, sp->hdr.seq,
+ conn->abort_code, conn->error);
+ break;
+ default:
+ BUG();
+ }
+ spin_unlock(&conn->state_lock);
+ spin_unlock(&rx->incoming_lock);
+
+ rxrpc_send_ping(call, skb);
+
+ /* We have to discard the prealloc queue's ref here and rely on a
+ * combination of the RCU read lock and refs held either by the socket
+ * (recvmsg queue, to-be-accepted queue or user ID tree) or the kernel
+ * service to prevent the call from being deallocated too early.
+ */
+ rxrpc_put_call(call, rxrpc_call_put);
+
+ _leave(" = %p{%d}", call, call->debug_id);
+ return call;
+
+no_call:
+ spin_unlock(&rx->incoming_lock);
+ _leave(" = NULL [%u]", skb->mark);
+ return NULL;
+}
+
+/*
+ * Charge up socket with preallocated calls, attaching user call IDs.
+ */
+int rxrpc_user_charge_accept(struct rxrpc_sock *rx, unsigned long user_call_ID)
+{
+ struct rxrpc_backlog *b = rx->backlog;
+
+ if (rx->sk.sk_state == RXRPC_CLOSE)
+ return -ESHUTDOWN;
+
+ return rxrpc_service_prealloc_one(rx, b, NULL, NULL, user_call_ID,
+ GFP_KERNEL,
+ atomic_inc_return(&rxrpc_debug_id));
+}
+
+/*
+ * rxrpc_kernel_charge_accept - Charge up socket with preallocated calls
+ * @sock: The socket on which to preallocate
+ * @notify_rx: Event notification function for the call
+ * @user_attach_call: Func to attach call to user_call_ID
+ * @user_call_ID: The tag to attach to the preallocated call
+ * @gfp: The allocation conditions.
+ * @debug_id: The tracing debug ID.
+ *
+ * Charge up the socket with preallocated calls, each with a user ID. A
+ * function should be provided to effect the attachment from the user's side.
+ * The user is given a ref to hold on the call.
+ *
+ * Note that the call may be come connected before this function returns.
+ */
+int rxrpc_kernel_charge_accept(struct socket *sock,
+ rxrpc_notify_rx_t notify_rx,
+ rxrpc_user_attach_call_t user_attach_call,
+ unsigned long user_call_ID, gfp_t gfp,
+ unsigned int debug_id)
+{
+ struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
+ struct rxrpc_backlog *b = rx->backlog;
+
+ if (sock->sk->sk_state == RXRPC_CLOSE)
+ return -ESHUTDOWN;
+
+ return rxrpc_service_prealloc_one(rx, b, notify_rx,
+ user_attach_call, user_call_ID,
+ gfp, debug_id);
+}
+EXPORT_SYMBOL(rxrpc_kernel_charge_accept);