diff mbox series

[net-next,5/9] net: tcp: make tcp_rcv_synsent_state_process() return drop reasons

Message ID 20220516034519.184876-6-imagedong@tencent.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: tcp: add skb drop reasons to tcp state change | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next, async
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 fail Errors and warnings before: 5741 this patch: 5741
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang fail Errors and warnings before: 1141 this patch: 1141
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 fail Errors and warnings before: 5887 this patch: 5887
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 32 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Menglong Dong May 16, 2022, 3:45 a.m. UTC 
From: Menglong Dong <imagedong@tencent.com>

The return value of tcp_rcv_synsent_state_process() can be -1, 0 or 1:

- -1: free skb silently
- 0: success and skb is already freed
- 1: drop packet and send a RST

Therefore, we can make it return skb drop reasons on 'reset_and_undo'
path, which will not impact the caller.

The new reason 'TCP_PAWSACTIVEREJECTED' is added, which is corresponding
to LINUX_MIB_PAWSACTIVEREJECTED.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
 include/linux/skbuff.h | 1 +
 net/ipv4/tcp_input.c   | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 3c7b1e9aabbb..36e0971f4cc9 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -619,6 +619,7 @@  struct sk_buff;
 	FN(IP_INNOROUTES)		\
 	FN(PKT_TOO_BIG)			\
 	FN(SOCKET_DESTROYED)		\
+	FN(TCP_PAWSACTIVEREJECTED)	\
 	FN(MAX)
 
 /* The reason of skb drop, which is used in kfree_skb_reason().
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 97cfcd85f84e..e8d26a68bc45 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6174,6 +6174,10 @@  static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 				inet_csk_reset_xmit_timer(sk,
 						ICSK_TIME_RETRANS,
 						TCP_TIMEOUT_MIN, TCP_RTO_MAX);
+			if (after(TCP_SKB_CB(skb)->ack_seq, tp->snd_nxt))
+				SKB_DR_SET(reason, TCP_ACK_UNSENT_DATA);
+			else
+				SKB_DR_SET(reason, TCP_TOO_OLD_ACK);
 			goto reset_and_undo;
 		}
 
@@ -6182,6 +6186,7 @@  static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 			     tcp_time_stamp(tp))) {
 			NET_INC_STATS(sock_net(sk),
 					LINUX_MIB_PAWSACTIVEREJECTED);
+			SKB_DR_SET(reason, TCP_PAWSACTIVEREJECTED);
 			goto reset_and_undo;
 		}
 
@@ -6375,7 +6380,7 @@  static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 reset_and_undo:
 	tcp_clear_options(&tp->rx_opt);
 	tp->rx_opt.mss_clamp = saved_clamp;
-	return 1;
+	return reason;
 }
 
 static void tcp_rcv_synrecv_state_fastopen(struct sock *sk)