Commit 669da7a7 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: add drop reasons to tcp_rcv_state_process() 



Add basic support for drop reasons in tcp_rcv_state_process()

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 37fd4e84

include/linux/skbuff.h

+3 −0
Original line number Diff line number Diff line
@@ -387,6 +387,9 @@ enum skb_drop_reason { 
	SKB_DROP_REASON_TCP_INVALID_SEQUENCE, /* Not acceptable SEQ field */

	SKB_DROP_REASON_TCP_RESET,	/* Invalid RST packet */

	SKB_DROP_REASON_TCP_INVALID_SYN, /* Incoming packet has unexpected SYN flag */

	SKB_DROP_REASON_TCP_CLOSE,	/* TCP socket in CLOSE state */

	SKB_DROP_REASON_TCP_FASTOPEN,	/* dropped by FASTOPEN request socket */

	SKB_DROP_REASON_TCP_OLD_ACK,	/* TCP ACK is old, but in window */

	SKB_DROP_REASON_IP_OUTNOROUTES,	/* route lookup failed */

	SKB_DROP_REASON_BPF_CGROUP_EGRESS,	/* dropped by

						 * BPF_PROG_TYPE_CGROUP_SKB

include/trace/events/skb.h

+3 −0
Original line number Diff line number Diff line
@@ -42,6 +42,9 @@ 
	   TCP_INVALID_SEQUENCE)				\

	EM(SKB_DROP_REASON_TCP_RESET, TCP_RESET)		\

	EM(SKB_DROP_REASON_TCP_INVALID_SYN, TCP_INVALID_SYN)	\

	EM(SKB_DROP_REASON_TCP_CLOSE, TCP_CLOSE)		\

	EM(SKB_DROP_REASON_TCP_FASTOPEN, TCP_FASTOPEN)		\

	EM(SKB_DROP_REASON_TCP_OLD_ACK, TCP_OLD_ACK)		\

	EM(SKB_DROP_REASON_IP_OUTNOROUTES, IP_OUTNOROUTES)	\

	EM(SKB_DROP_REASON_BPF_CGROUP_EGRESS,			\

	   BPF_CGROUP_EGRESS)					\

net/ipv4/tcp_input.c

+17 −7
Original line number Diff line number Diff line
@@ -6413,21 +6413,26 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb) 
	struct request_sock *req;

	int queued = 0;

	bool acceptable;

	SKB_DR(reason);



	switch (sk->sk_state) {

	case TCP_CLOSE:

		SKB_DR_SET(reason, TCP_CLOSE);

		goto discard;



	case TCP_LISTEN:

		if (th->ack)

			return 1;



		if (th->rst)

		if (th->rst) {

			SKB_DR_SET(reason, TCP_RESET);

			goto discard;



		}

		if (th->syn) {

			if (th->fin)

			if (th->fin) {

				SKB_DR_SET(reason, TCP_FLAGS);

				goto discard;

			}

			/* It is possible that we process SYN packets from backlog,

			 * so we need to make sure to disable BH and RCU right there.

			 */
@@ -6442,6 +6447,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb) 
			consume_skb(skb);

			return 0;

		}

		SKB_DR_SET(reason, TCP_FLAGS);

		goto discard;



	case TCP_SYN_SENT:
@@ -6468,13 +6474,16 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb) 
		WARN_ON_ONCE(sk->sk_state != TCP_SYN_RECV &&

		    sk->sk_state != TCP_FIN_WAIT1);



		if (!tcp_check_req(sk, skb, req, true, &req_stolen))

		if (!tcp_check_req(sk, skb, req, true, &req_stolen)) {

			SKB_DR_SET(reason, TCP_FASTOPEN);

			goto discard;

		}

	}



	if (!th->ack && !th->rst && !th->syn)

	if (!th->ack && !th->rst && !th->syn) {

		SKB_DR_SET(reason, TCP_FLAGS);

		goto discard;



	}

	if (!tcp_validate_incoming(sk, skb, th, 0))

		return 0;
@@ -6487,6 +6496,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb) 
		if (sk->sk_state == TCP_SYN_RECV)

			return 1;	/* send one RST */

		tcp_send_challenge_ack(sk);

		SKB_DR_SET(reason, TCP_OLD_ACK);

		goto discard;

	}

	switch (sk->sk_state) {
@@ -6647,7 +6657,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb) 


	if (!queued) {

discard:

		tcp_drop(sk, skb);

		tcp_drop_reason(sk, skb, reason);

	}

	return 0;