Commit e34100c2 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

tcp: add a drop_reason pointer to tcp_check_req() 



We want to add new drop reasons for packets dropped in 3WHS in the
following patches.

tcp_rcv_state_process() has to set reason to TCP_FASTOPEN,
because tcp_check_req() will conditionally overwrite the drop_reason.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarJason Xing <kerneljasonxing@gmail.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250301201424.2046477-2-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 3424291d

include/net/tcp.h

+1 −1
Original line number Diff line number Diff line
@@ -392,7 +392,7 @@ enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 
					      u32 *tw_isn);

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

			   struct request_sock *req, bool fastopen,

			   bool *lost_race);

			   bool *lost_race, enum skb_drop_reason *drop_reason);

enum skb_drop_reason tcp_child_process(struct sock *parent, struct sock *child,

				       struct sk_buff *skb);

void tcp_enter_loss(struct sock *sk);

net/ipv4/tcp_input.c

+2 −3
Original line number Diff line number Diff line
@@ -6812,11 +6812,10 @@ 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)) {

		SKB_DR_SET(reason, TCP_FASTOPEN);

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

			goto discard;

	}

	}



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

		SKB_DR_SET(reason, TCP_FLAGS);

net/ipv4/tcp_ipv4.c

+2 −1
Original line number Diff line number Diff line
@@ -2265,7 +2265,8 @@ int tcp_v4_rcv(struct sk_buff *skb) 
			th = (const struct tcphdr *)skb->data;

			iph = ip_hdr(skb);

			tcp_v4_fill_cb(skb, iph, th);

			nsk = tcp_check_req(sk, skb, req, false, &req_stolen);

			nsk = tcp_check_req(sk, skb, req, false, &req_stolen,

					    &drop_reason);

		} else {

			drop_reason = SKB_DROP_REASON_SOCKET_FILTER;

		}

net/ipv4/tcp_minisocks.c

+2 −1
Original line number Diff line number Diff line
@@ -657,7 +657,8 @@ EXPORT_SYMBOL(tcp_create_openreq_child); 


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

			   struct request_sock *req,

			   bool fastopen, bool *req_stolen)

			   bool fastopen, bool *req_stolen,

			   enum skb_drop_reason *drop_reason)

{

	struct tcp_options_received tmp_opt;

	struct sock *child;

net/ipv6/tcp_ipv6.c

+2 −1
Original line number Diff line number Diff line
@@ -1828,7 +1828,8 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb) 
			th = (const struct tcphdr *)skb->data;

			hdr = ipv6_hdr(skb);

			tcp_v6_fill_cb(skb, hdr, th);

			nsk = tcp_check_req(sk, skb, req, false, &req_stolen);

			nsk = tcp_check_req(sk, skb, req, false, &req_stolen,

					    &drop_reason);

		} else {

			drop_reason = SKB_DROP_REASON_SOCKET_FILTER;

		}