From 55fb874b6e47f44865f2ef251d492501d749af2e Mon Sep 17 00:00:00 2001 From: Kelly Littlepage Date: Tue, 22 Sep 2020 10:15:02 +0800 Subject: [PATCH] net: tcp: fix rx timestamp behavior for tcp_recvmsg stable inclusion from linux-4.19.124 commit 31080a892c54dd7852b24c584b9a5f904708fb6f -------------------------------- [ Upstream commit cc4de047b33be247f9c8150d3e496743a49642b8 ] The stated intent of the original commit is to is to "return the timestamp corresponding to the highest sequence number data returned." The current implementation returns the timestamp for the last byte of the last fully read skb, which is not necessarily the last byte in the recv buffer. This patch converts behavior to the original definition, and to the behavior of the previous draft versions of commit 98aaa913b4ed ("tcp: Extend SOF_TIMESTAMPING_RX_SOFTWARE to TCP recvmsg") which also match this behavior. Fixes: 98aaa913b4ed ("tcp: Extend SOF_TIMESTAMPING_RX_SOFTWARE to TCP recvmsg") Co-developed-by: Iris Liu Signed-off-by: Iris Liu Signed-off-by: Kelly Littlepage Signed-off-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Acked-by: Willem de Bruijn Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman Signed-off-by: Yang Yingliang Signed-off-by: Li Aichun Reviewed-by: guodeqing Signed-off-by: Yang Yingliang --- net/ipv4/tcp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 8ccd1ae13253..9ac0cdd1aec2 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2135,14 +2135,16 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, tp->urg_data = 0; tcp_fast_path_check(sk); } - if (used + offset < skb->len) - continue; if (TCP_SKB_CB(skb)->has_rxtstamp) { tcp_update_recv_tstamps(skb, &tss); has_tss = true; has_cmsg = true; } + + if (used + offset < skb->len) + continue; + if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) goto found_fin_ok; if (!(flags & MSG_PEEK)) -- GitLab