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Commit ef449678 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'tcp_fast_open_synack_fin' 



Eric Dumazet says:

====================
tcp: fastopen: accept data/FIN present in SYNACK

Implements RFC 7413 (TCP Fast Open) 4.2.2, accepting payload and/or FIN
in SYNACK messages, and prepare removal of SYN flag in tcp_recvmsg()
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents df03288b 9d691539

include/net/tcp.h

+1 −0
Original line number Diff line number Diff line
@@ -1437,6 +1437,7 @@ void tcp_free_fastopen_req(struct tcp_sock *tp); 


extern struct tcp_fastopen_context __rcu *tcp_fastopen_ctx;

int tcp_fastopen_reset_cipher(void *key, unsigned int len);

void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb);

struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,

			      struct request_sock *req,

			      struct tcp_fastopen_cookie *foc,

net/ipv4/tcp.c

+6 −2
Original line number Diff line number Diff line
@@ -1466,8 +1466,10 @@ static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) 


	while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {

		offset = seq - TCP_SKB_CB(skb)->seq;

		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)

		if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {

			pr_err_once("%s: found a SYN, please report !\n", __func__);

			offset--;

		}

		if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {

			*off = offset;

			return skb;
@@ -1657,8 +1659,10 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, 
				break;



			offset = *seq - TCP_SKB_CB(skb)->seq;

			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)

			if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {

				pr_err_once("%s: found a SYN, please report !\n", __func__);

				offset--;

			}

			if (offset < skb->len)

				goto found_ok_skb;

			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)

net/ipv4/tcp_fastopen.c

+37 −30
Original line number Diff line number Diff line
@@ -124,6 +124,38 @@ static bool tcp_fastopen_cookie_gen(struct request_sock *req, 
	return false;

}





/* If an incoming SYN or SYNACK frame contains a payload and/or FIN,

 * queue this additional data / FIN.

 */

void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb)

{

	struct tcp_sock *tp = tcp_sk(sk);



	if (TCP_SKB_CB(skb)->end_seq == tp->rcv_nxt)

		return;



	skb = skb_clone(skb, GFP_ATOMIC);

	if (!skb)

		return;



	skb_dst_drop(skb);

	__skb_pull(skb, tcp_hdrlen(skb));

	skb_set_owner_r(skb, sk);



	TCP_SKB_CB(skb)->seq++;

	TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_SYN;



	tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;

	__skb_queue_tail(&sk->sk_receive_queue, skb);

	tp->syn_data_acked = 1;



	/* u64_stats_update_begin(&tp->syncp) not needed here,

	 * as we certainly are not changing upper 32bit value (0)

	 */

	tp->bytes_received = skb->len;

}



static struct sock *tcp_fastopen_create_child(struct sock *sk,

					      struct sk_buff *skb,

					      struct dst_entry *dst,
@@ -132,7 +164,6 @@ static struct sock *tcp_fastopen_create_child(struct sock *sk, 
	struct tcp_sock *tp;

	struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;

	struct sock *child;

	u32 end_seq;

	bool own_req;



	req->num_retrans = 0;
@@ -178,35 +209,11 @@ static struct sock *tcp_fastopen_create_child(struct sock *sk, 
	tcp_init_metrics(child);

	tcp_init_buffer_space(child);



	/* Queue the data carried in the SYN packet.

	 * We used to play tricky games with skb_get().

	 * With lockless listener, it is a dead end.

	 * Do not think about it.

	 *

	 * XXX (TFO) - we honor a zero-payload TFO request for now,

	 * (any reason not to?) but no need to queue the skb since

	 * there is no data. How about SYN+FIN?

	 */

	end_seq = TCP_SKB_CB(skb)->end_seq;

	if (end_seq != TCP_SKB_CB(skb)->seq + 1) {

		struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);



		if (likely(skb2)) {

			skb_dst_drop(skb2);

			__skb_pull(skb2, tcp_hdrlen(skb));

			skb_set_owner_r(skb2, child);

			__skb_queue_tail(&child->sk_receive_queue, skb2);

			tp->syn_data_acked = 1;

	tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;



			/* u64_stats_update_begin(&tp->syncp) not needed here,

			 * as we certainly are not changing upper 32bit value (0)

			 */

			tp->bytes_received = end_seq - TCP_SKB_CB(skb)->seq - 1;

		} else {

			end_seq = TCP_SKB_CB(skb)->seq + 1;

		}

	}

	tcp_rsk(req)->rcv_nxt = tp->rcv_nxt = end_seq;

	tcp_fastopen_add_skb(child, skb);



	tcp_rsk(req)->rcv_nxt = tp->rcv_nxt;

	/* tcp_conn_request() is sending the SYNACK,

	 * and queues the child into listener accept queue.

	 */

net/ipv4/tcp_input.c

+3 −0
Original line number Diff line number Diff line
@@ -5509,6 +5509,9 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack, 
	tp->syn_data_acked = tp->syn_data;

	if (tp->syn_data_acked)

		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPFASTOPENACTIVE);



	tcp_fastopen_add_skb(sk, synack);



	return false;

}