From 8df010e4c84d5b3518e698e1a89dc2b0a87f2be9 Mon Sep 17 00:00:00 2001 From: Kelly Littlepage Date: Fri, 8 May 2020 19:58:46 +0000 Subject: [PATCH] net: tcp: fix rx timestamp behavior for tcp_recvmsg [ 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 --- 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 0c69b66d93d7..6fbfdd5e96de 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1977,13 +1977,15 @@ skip_copy: 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; } + + if (used + offset < skb->len) + continue; + if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) goto found_fin_ok; if (!(flags & MSG_PEEK))