From a166140e810e74682f3ca248ef3879177b5c1315 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Mon, 25 Apr 2016 14:44:50 -0700 Subject: tcp: Handle eor bit when fragmenting a skb When fragmenting a skb, the next_skb should carry the eor from prev_skb. The eor of prev_skb should also be reset. Packetdrill script for testing: ~~~~~~ +0 `sysctl -q -w net.ipv4.tcp_min_tso_segs=10` +0 `sysctl -q -w net.ipv4.tcp_no_metrics_save=1` +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 0.100 < S 0:0(0) win 32792 0.100 > S. 0:0(0) ack 1 0.200 < . 1:1(0) ack 1 win 257 0.200 accept(3, ..., ...) = 4 +0 setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0 0.200 sendto(4, ..., 15330, MSG_EOR, ..., ...) = 15330 0.200 sendto(4, ..., 730, 0, ..., ...) = 730 0.200 > . 1:7301(7300) ack 1 0.200 > . 7301:14601(7300) ack 1 0.300 < . 1:1(0) ack 14601 win 257 0.300 > P. 14601:15331(730) ack 1 0.300 > P. 15331:16061(730) ack 1 0.400 < . 1:1(0) ack 16061 win 257 0.400 close(4) = 0 0.400 > F. 16061:16061(0) ack 1 0.400 < F. 1:1(0) ack 16062 win 257 0.400 > . 16062:16062(0) ack 2 Signed-off-by: Martin KaFai Lau Cc: Eric Dumazet Cc: Neal Cardwell Cc: Soheil Hassas Yeganeh Cc: Willem de Bruijn Cc: Yuchung Cheng Acked-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller --- net/ipv4/tcp_output.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'net') diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 77c6cbb897e6..1a487ff95d4c 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1134,6 +1134,12 @@ static void tcp_fragment_tstamp(struct sk_buff *skb, struct sk_buff *skb2) } } +static void tcp_skb_fragment_eor(struct sk_buff *skb, struct sk_buff *skb2) +{ + TCP_SKB_CB(skb2)->eor = TCP_SKB_CB(skb)->eor; + TCP_SKB_CB(skb)->eor = 0; +} + /* Function to create two new TCP segments. Shrinks the given segment * to the specified size and appends a new segment with the rest of the * packet to the list. This won't be called frequently, I hope. @@ -1179,6 +1185,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, TCP_SKB_CB(skb)->tcp_flags = flags & ~(TCPHDR_FIN | TCPHDR_PSH); TCP_SKB_CB(buff)->tcp_flags = flags; TCP_SKB_CB(buff)->sacked = TCP_SKB_CB(skb)->sacked; + tcp_skb_fragment_eor(skb, buff); if (!skb_shinfo(skb)->nr_frags && skb->ip_summed != CHECKSUM_PARTIAL) { /* Copy and checksum data tail into the new buffer. */ @@ -1739,6 +1746,8 @@ static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len, /* This packet was never sent out yet, so no SACK bits. */ TCP_SKB_CB(buff)->sacked = 0; + tcp_skb_fragment_eor(skb, buff); + buff->ip_summed = skb->ip_summed = CHECKSUM_PARTIAL; skb_split(skb, buff, len); tcp_fragment_tstamp(skb, buff); -- cgit v1.2.3