diff mbox series

[net-next,08/10] tcp: make tcp_rcv_synsent_state_process() drop monitor friend

Message ID 20220416001048.2218911-9-eric.dumazet@gmail.com (mailing list archive)
State Accepted
Commit c337578a6592d671c5e78accc55f00cc594fe2da
Delegated to: Netdev Maintainers
Headers show
Series tcp: drop reason additions | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/cc_maintainers warning 2 maintainers not CCed: yoshfuji@linux-ipv6.org dsahern@kernel.org
netdev/build_clang success Errors and warnings before: 9 this patch: 9
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 3 this patch: 3
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 42 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet April 16, 2022, 12:10 a.m. UTC 
From: Eric Dumazet <edumazet@google.com>

1) A valid RST packet should be consumed, to not confuse drop monitor.

2) Same remark for packet validating cross syn setup,
   even if we might ignore part of it.

3) When third packet of 3WHS is delayed, do not pretend
   the SYNACK was dropped.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv4/tcp_input.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a1077adeb1b62d74b5f1c9a6fc34def44ae07790..cd9f5c39f85a042751ef78132860a2a6cc96bccc 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6186,7 +6186,9 @@  static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 
 		if (th->rst) {
 			tcp_reset(sk, skb);
-			goto discard;
+consume:
+			__kfree_skb(skb);
+			return 0;
 		}
 
 		/* rfc793:
@@ -6275,13 +6277,9 @@  static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 			tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);
 			inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
 						  TCP_DELACK_MAX, TCP_RTO_MAX);
-
-discard:
-			tcp_drop(sk, skb);
-			return 0;
-		} else {
-			tcp_send_ack(sk);
+			goto consume;
 		}
+		tcp_send_ack(sk);
 		return -1;
 	}
 
@@ -6350,7 +6348,7 @@  static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 		 */
 		return -1;
 #else
-		goto discard;
+		goto consume;
 #endif
 	}
 	/* "fifth, if neither of the SYN or RST bits is set then
@@ -6360,7 +6358,8 @@  static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 discard_and_undo:
 	tcp_clear_options(&tp->rx_opt);
 	tp->rx_opt.mss_clamp = saved_clamp;
-	goto discard;
+	tcp_drop(sk, skb);
+	return 0;
 
 reset_and_undo:
 	tcp_clear_options(&tp->rx_opt);