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-rw-r--r--net/xfrm/espintcp.c581
1 files changed, 581 insertions, 0 deletions
diff --git a/net/xfrm/espintcp.c b/net/xfrm/espintcp.c
new file mode 100644
index 000000000..24ca49ece
--- /dev/null
+++ b/net/xfrm/espintcp.c
@@ -0,0 +1,581 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <net/tcp.h>
+#include <net/strparser.h>
+#include <net/xfrm.h>
+#include <net/esp.h>
+#include <net/espintcp.h>
+#include <linux/skmsg.h>
+#include <net/inet_common.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/ipv6_stubs.h>
+#endif
+
+static void handle_nonesp(struct espintcp_ctx *ctx, struct sk_buff *skb,
+ struct sock *sk)
+{
+ if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf ||
+ !sk_rmem_schedule(sk, skb, skb->truesize)) {
+ XFRM_INC_STATS(sock_net(sk), LINUX_MIB_XFRMINERROR);
+ kfree_skb(skb);
+ return;
+ }
+
+ skb_set_owner_r(skb, sk);
+
+ memset(skb->cb, 0, sizeof(skb->cb));
+ skb_queue_tail(&ctx->ike_queue, skb);
+ ctx->saved_data_ready(sk);
+}
+
+static void handle_esp(struct sk_buff *skb, struct sock *sk)
+{
+ struct tcp_skb_cb *tcp_cb = (struct tcp_skb_cb *)skb->cb;
+
+ skb_reset_transport_header(skb);
+
+ /* restore IP CB, we need at least IP6CB->nhoff */
+ memmove(skb->cb, &tcp_cb->header, sizeof(tcp_cb->header));
+
+ rcu_read_lock();
+ skb->dev = dev_get_by_index_rcu(sock_net(sk), skb->skb_iif);
+ local_bh_disable();
+#if IS_ENABLED(CONFIG_IPV6)
+ if (sk->sk_family == AF_INET6)
+ ipv6_stub->xfrm6_rcv_encap(skb, IPPROTO_ESP, 0, TCP_ENCAP_ESPINTCP);
+ else
+#endif
+ xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, TCP_ENCAP_ESPINTCP);
+ local_bh_enable();
+ rcu_read_unlock();
+}
+
+static void espintcp_rcv(struct strparser *strp, struct sk_buff *skb)
+{
+ struct espintcp_ctx *ctx = container_of(strp, struct espintcp_ctx,
+ strp);
+ struct strp_msg *rxm = strp_msg(skb);
+ int len = rxm->full_len - 2;
+ u32 nonesp_marker;
+ int err;
+
+ /* keepalive packet? */
+ if (unlikely(len == 1)) {
+ u8 data;
+
+ err = skb_copy_bits(skb, rxm->offset + 2, &data, 1);
+ if (err < 0) {
+ XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR);
+ kfree_skb(skb);
+ return;
+ }
+
+ if (data == 0xff) {
+ kfree_skb(skb);
+ return;
+ }
+ }
+
+ /* drop other short messages */
+ if (unlikely(len <= sizeof(nonesp_marker))) {
+ XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR);
+ kfree_skb(skb);
+ return;
+ }
+
+ err = skb_copy_bits(skb, rxm->offset + 2, &nonesp_marker,
+ sizeof(nonesp_marker));
+ if (err < 0) {
+ XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR);
+ kfree_skb(skb);
+ return;
+ }
+
+ /* remove header, leave non-ESP marker/SPI */
+ if (!__pskb_pull(skb, rxm->offset + 2)) {
+ XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINERROR);
+ kfree_skb(skb);
+ return;
+ }
+
+ if (pskb_trim(skb, rxm->full_len - 2) != 0) {
+ XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINERROR);
+ kfree_skb(skb);
+ return;
+ }
+
+ if (nonesp_marker == 0)
+ handle_nonesp(ctx, skb, strp->sk);
+ else
+ handle_esp(skb, strp->sk);
+}
+
+static int espintcp_parse(struct strparser *strp, struct sk_buff *skb)
+{
+ struct strp_msg *rxm = strp_msg(skb);
+ __be16 blen;
+ u16 len;
+ int err;
+
+ if (skb->len < rxm->offset + 2)
+ return 0;
+
+ err = skb_copy_bits(skb, rxm->offset, &blen, sizeof(blen));
+ if (err < 0)
+ return err;
+
+ len = be16_to_cpu(blen);
+ if (len < 2)
+ return -EINVAL;
+
+ return len;
+}
+
+static int espintcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
+ int nonblock, int flags, int *addr_len)
+{
+ struct espintcp_ctx *ctx = espintcp_getctx(sk);
+ struct sk_buff *skb;
+ int err = 0;
+ int copied;
+ int off = 0;
+
+ flags |= nonblock ? MSG_DONTWAIT : 0;
+
+ skb = __skb_recv_datagram(sk, &ctx->ike_queue, flags, &off, &err);
+ if (!skb) {
+ if (err == -EAGAIN && sk->sk_shutdown & RCV_SHUTDOWN)
+ return 0;
+ return err;
+ }
+
+ copied = len;
+ if (copied > skb->len)
+ copied = skb->len;
+ else if (copied < skb->len)
+ msg->msg_flags |= MSG_TRUNC;
+
+ err = skb_copy_datagram_msg(skb, 0, msg, copied);
+ if (unlikely(err)) {
+ kfree_skb(skb);
+ return err;
+ }
+
+ if (flags & MSG_TRUNC)
+ copied = skb->len;
+ kfree_skb(skb);
+ return copied;
+}
+
+int espintcp_queue_out(struct sock *sk, struct sk_buff *skb)
+{
+ struct espintcp_ctx *ctx = espintcp_getctx(sk);
+
+ if (skb_queue_len(&ctx->out_queue) >= READ_ONCE(netdev_max_backlog))
+ return -ENOBUFS;
+
+ __skb_queue_tail(&ctx->out_queue, skb);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(espintcp_queue_out);
+
+/* espintcp length field is 2B and length includes the length field's size */
+#define MAX_ESPINTCP_MSG (((1 << 16) - 1) - 2)
+
+static int espintcp_sendskb_locked(struct sock *sk, struct espintcp_msg *emsg,
+ int flags)
+{
+ do {
+ int ret;
+
+ ret = skb_send_sock_locked(sk, emsg->skb,
+ emsg->offset, emsg->len);
+ if (ret < 0)
+ return ret;
+
+ emsg->len -= ret;
+ emsg->offset += ret;
+ } while (emsg->len > 0);
+
+ kfree_skb(emsg->skb);
+ memset(emsg, 0, sizeof(*emsg));
+
+ return 0;
+}
+
+static int espintcp_sendskmsg_locked(struct sock *sk,
+ struct espintcp_msg *emsg, int flags)
+{
+ struct sk_msg *skmsg = &emsg->skmsg;
+ struct scatterlist *sg;
+ int done = 0;
+ int ret;
+
+ flags |= MSG_SENDPAGE_NOTLAST;
+ sg = &skmsg->sg.data[skmsg->sg.start];
+ do {
+ size_t size = sg->length - emsg->offset;
+ int offset = sg->offset + emsg->offset;
+ struct page *p;
+
+ emsg->offset = 0;
+
+ if (sg_is_last(sg))
+ flags &= ~MSG_SENDPAGE_NOTLAST;
+
+ p = sg_page(sg);
+retry:
+ ret = do_tcp_sendpages(sk, p, offset, size, flags);
+ if (ret < 0) {
+ emsg->offset = offset - sg->offset;
+ skmsg->sg.start += done;
+ return ret;
+ }
+
+ if (ret != size) {
+ offset += ret;
+ size -= ret;
+ goto retry;
+ }
+
+ done++;
+ put_page(p);
+ sk_mem_uncharge(sk, sg->length);
+ sg = sg_next(sg);
+ } while (sg);
+
+ memset(emsg, 0, sizeof(*emsg));
+
+ return 0;
+}
+
+static int espintcp_push_msgs(struct sock *sk, int flags)
+{
+ struct espintcp_ctx *ctx = espintcp_getctx(sk);
+ struct espintcp_msg *emsg = &ctx->partial;
+ int err;
+
+ if (!emsg->len)
+ return 0;
+
+ if (ctx->tx_running)
+ return -EAGAIN;
+ ctx->tx_running = 1;
+
+ if (emsg->skb)
+ err = espintcp_sendskb_locked(sk, emsg, flags);
+ else
+ err = espintcp_sendskmsg_locked(sk, emsg, flags);
+ if (err == -EAGAIN) {
+ ctx->tx_running = 0;
+ return flags & MSG_DONTWAIT ? -EAGAIN : 0;
+ }
+ if (!err)
+ memset(emsg, 0, sizeof(*emsg));
+
+ ctx->tx_running = 0;
+
+ return err;
+}
+
+int espintcp_push_skb(struct sock *sk, struct sk_buff *skb)
+{
+ struct espintcp_ctx *ctx = espintcp_getctx(sk);
+ struct espintcp_msg *emsg = &ctx->partial;
+ unsigned int len;
+ int offset;
+
+ if (sk->sk_state != TCP_ESTABLISHED) {
+ kfree_skb(skb);
+ return -ECONNRESET;
+ }
+
+ offset = skb_transport_offset(skb);
+ len = skb->len - offset;
+
+ espintcp_push_msgs(sk, 0);
+
+ if (emsg->len) {
+ kfree_skb(skb);
+ return -ENOBUFS;
+ }
+
+ skb_set_owner_w(skb, sk);
+
+ emsg->offset = offset;
+ emsg->len = len;
+ emsg->skb = skb;
+
+ espintcp_push_msgs(sk, 0);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(espintcp_push_skb);
+
+static int espintcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
+{
+ long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
+ struct espintcp_ctx *ctx = espintcp_getctx(sk);
+ struct espintcp_msg *emsg = &ctx->partial;
+ struct iov_iter pfx_iter;
+ struct kvec pfx_iov = {};
+ size_t msglen = size + 2;
+ char buf[2] = {0};
+ int err, end;
+
+ if (msg->msg_flags & ~MSG_DONTWAIT)
+ return -EOPNOTSUPP;
+
+ if (size > MAX_ESPINTCP_MSG)
+ return -EMSGSIZE;
+
+ if (msg->msg_controllen)
+ return -EOPNOTSUPP;
+
+ lock_sock(sk);
+
+ err = espintcp_push_msgs(sk, msg->msg_flags & MSG_DONTWAIT);
+ if (err < 0) {
+ if (err != -EAGAIN || !(msg->msg_flags & MSG_DONTWAIT))
+ err = -ENOBUFS;
+ goto unlock;
+ }
+
+ sk_msg_init(&emsg->skmsg);
+ while (1) {
+ /* only -ENOMEM is possible since we don't coalesce */
+ err = sk_msg_alloc(sk, &emsg->skmsg, msglen, 0);
+ if (!err)
+ break;
+
+ err = sk_stream_wait_memory(sk, &timeo);
+ if (err)
+ goto fail;
+ }
+
+ *((__be16 *)buf) = cpu_to_be16(msglen);
+ pfx_iov.iov_base = buf;
+ pfx_iov.iov_len = sizeof(buf);
+ iov_iter_kvec(&pfx_iter, WRITE, &pfx_iov, 1, pfx_iov.iov_len);
+
+ err = sk_msg_memcopy_from_iter(sk, &pfx_iter, &emsg->skmsg,
+ pfx_iov.iov_len);
+ if (err < 0)
+ goto fail;
+
+ err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, &emsg->skmsg, size);
+ if (err < 0)
+ goto fail;
+
+ end = emsg->skmsg.sg.end;
+ emsg->len = size;
+ sk_msg_iter_var_prev(end);
+ sg_mark_end(sk_msg_elem(&emsg->skmsg, end));
+
+ tcp_rate_check_app_limited(sk);
+
+ err = espintcp_push_msgs(sk, msg->msg_flags & MSG_DONTWAIT);
+ /* this message could be partially sent, keep it */
+
+ release_sock(sk);
+
+ return size;
+
+fail:
+ sk_msg_free(sk, &emsg->skmsg);
+ memset(emsg, 0, sizeof(*emsg));
+unlock:
+ release_sock(sk);
+ return err;
+}
+
+static struct proto espintcp_prot __ro_after_init;
+static struct proto_ops espintcp_ops __ro_after_init;
+static struct proto espintcp6_prot;
+static struct proto_ops espintcp6_ops;
+static DEFINE_MUTEX(tcpv6_prot_mutex);
+
+static void espintcp_data_ready(struct sock *sk)
+{
+ struct espintcp_ctx *ctx = espintcp_getctx(sk);
+
+ strp_data_ready(&ctx->strp);
+}
+
+static void espintcp_tx_work(struct work_struct *work)
+{
+ struct espintcp_ctx *ctx = container_of(work,
+ struct espintcp_ctx, work);
+ struct sock *sk = ctx->strp.sk;
+
+ lock_sock(sk);
+ if (!ctx->tx_running)
+ espintcp_push_msgs(sk, 0);
+ release_sock(sk);
+}
+
+static void espintcp_write_space(struct sock *sk)
+{
+ struct espintcp_ctx *ctx = espintcp_getctx(sk);
+
+ schedule_work(&ctx->work);
+ ctx->saved_write_space(sk);
+}
+
+static void espintcp_destruct(struct sock *sk)
+{
+ struct espintcp_ctx *ctx = espintcp_getctx(sk);
+
+ ctx->saved_destruct(sk);
+ kfree(ctx);
+}
+
+bool tcp_is_ulp_esp(struct sock *sk)
+{
+ return sk->sk_prot == &espintcp_prot || sk->sk_prot == &espintcp6_prot;
+}
+EXPORT_SYMBOL_GPL(tcp_is_ulp_esp);
+
+static void build_protos(struct proto *espintcp_prot,
+ struct proto_ops *espintcp_ops,
+ const struct proto *orig_prot,
+ const struct proto_ops *orig_ops);
+static int espintcp_init_sk(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct strp_callbacks cb = {
+ .rcv_msg = espintcp_rcv,
+ .parse_msg = espintcp_parse,
+ };
+ struct espintcp_ctx *ctx;
+ int err;
+
+ /* sockmap is not compatible with espintcp */
+ if (sk->sk_user_data)
+ return -EBUSY;
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ err = strp_init(&ctx->strp, sk, &cb);
+ if (err)
+ goto free;
+
+ __sk_dst_reset(sk);
+
+ strp_check_rcv(&ctx->strp);
+ skb_queue_head_init(&ctx->ike_queue);
+ skb_queue_head_init(&ctx->out_queue);
+
+ if (sk->sk_family == AF_INET) {
+ sk->sk_prot = &espintcp_prot;
+ sk->sk_socket->ops = &espintcp_ops;
+ } else {
+ mutex_lock(&tcpv6_prot_mutex);
+ if (!espintcp6_prot.recvmsg)
+ build_protos(&espintcp6_prot, &espintcp6_ops, sk->sk_prot, sk->sk_socket->ops);
+ mutex_unlock(&tcpv6_prot_mutex);
+
+ sk->sk_prot = &espintcp6_prot;
+ sk->sk_socket->ops = &espintcp6_ops;
+ }
+ ctx->saved_data_ready = sk->sk_data_ready;
+ ctx->saved_write_space = sk->sk_write_space;
+ ctx->saved_destruct = sk->sk_destruct;
+ sk->sk_data_ready = espintcp_data_ready;
+ sk->sk_write_space = espintcp_write_space;
+ sk->sk_destruct = espintcp_destruct;
+ rcu_assign_pointer(icsk->icsk_ulp_data, ctx);
+ INIT_WORK(&ctx->work, espintcp_tx_work);
+
+ /* avoid using task_frag */
+ sk->sk_allocation = GFP_ATOMIC;
+
+ return 0;
+
+free:
+ kfree(ctx);
+ return err;
+}
+
+static void espintcp_release(struct sock *sk)
+{
+ struct espintcp_ctx *ctx = espintcp_getctx(sk);
+ struct sk_buff_head queue;
+ struct sk_buff *skb;
+
+ __skb_queue_head_init(&queue);
+ skb_queue_splice_init(&ctx->out_queue, &queue);
+
+ while ((skb = __skb_dequeue(&queue)))
+ espintcp_push_skb(sk, skb);
+
+ tcp_release_cb(sk);
+}
+
+static void espintcp_close(struct sock *sk, long timeout)
+{
+ struct espintcp_ctx *ctx = espintcp_getctx(sk);
+ struct espintcp_msg *emsg = &ctx->partial;
+
+ strp_stop(&ctx->strp);
+
+ sk->sk_prot = &tcp_prot;
+ barrier();
+
+ cancel_work_sync(&ctx->work);
+ strp_done(&ctx->strp);
+
+ skb_queue_purge(&ctx->out_queue);
+ skb_queue_purge(&ctx->ike_queue);
+
+ if (emsg->len) {
+ if (emsg->skb)
+ kfree_skb(emsg->skb);
+ else
+ sk_msg_free(sk, &emsg->skmsg);
+ }
+
+ tcp_close(sk, timeout);
+}
+
+static __poll_t espintcp_poll(struct file *file, struct socket *sock,
+ poll_table *wait)
+{
+ __poll_t mask = datagram_poll(file, sock, wait);
+ struct sock *sk = sock->sk;
+ struct espintcp_ctx *ctx = espintcp_getctx(sk);
+
+ if (!skb_queue_empty(&ctx->ike_queue))
+ mask |= EPOLLIN | EPOLLRDNORM;
+
+ return mask;
+}
+
+static void build_protos(struct proto *espintcp_prot,
+ struct proto_ops *espintcp_ops,
+ const struct proto *orig_prot,
+ const struct proto_ops *orig_ops)
+{
+ memcpy(espintcp_prot, orig_prot, sizeof(struct proto));
+ memcpy(espintcp_ops, orig_ops, sizeof(struct proto_ops));
+ espintcp_prot->sendmsg = espintcp_sendmsg;
+ espintcp_prot->recvmsg = espintcp_recvmsg;
+ espintcp_prot->close = espintcp_close;
+ espintcp_prot->release_cb = espintcp_release;
+ espintcp_ops->poll = espintcp_poll;
+}
+
+static struct tcp_ulp_ops espintcp_ulp __read_mostly = {
+ .name = "espintcp",
+ .owner = THIS_MODULE,
+ .init = espintcp_init_sk,
+};
+
+void __init espintcp_init(void)
+{
+ build_protos(&espintcp_prot, &espintcp_ops, &tcp_prot, &inet_stream_ops);
+
+ tcp_register_ulp(&espintcp_ulp);
+}