diff options
| author | Eric Dumazet <edumazet@google.com> | 2016-08-22 11:31:10 -0700 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2016-09-29 11:14:09 +0200 |
| commit | 8ed803221d9a2a56b3a05d81250382629957178f (patch) | |
| tree | 2d549d07ed55364aafb83109dc6426708dd0427e | |
| parent | 522a16c9b6f120dd4fdfdfdf925a64128923e1a6 (diff) | |
| download | lwn-8ed803221d9a2a56b3a05d81250382629957178f.tar.gz lwn-8ed803221d9a2a56b3a05d81250382629957178f.zip | |
tcp: properly scale window in tcp_v[46]_reqsk_send_ack()
[ Upstream commit 20a2b49fc538540819a0c552877086548cff8d8d ]
When sending an ack in SYN_RECV state, we must scale the offered
window if wscale option was negotiated and accepted.
Tested:
Following packetdrill test demonstrates the issue :
0.000 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
// Establish a connection.
+0 < S 0:0(0) win 20000 <mss 1000,sackOK,wscale 7, nop, TS val 100 ecr 0>
+0 > S. 0:0(0) ack 1 win 28960 <mss 1460,sackOK, TS val 100 ecr 100, nop, wscale 7>
+0 < . 1:11(10) ack 1 win 156 <nop,nop,TS val 99 ecr 100>
// check that window is properly scaled !
+0 > . 1:1(0) ack 1 win 226 <nop,nop,TS val 200 ecr 100>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 8 | ||||
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 8 |
2 files changed, 14 insertions, 2 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 6184d17c9126..4b2040762733 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -809,8 +809,14 @@ static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt; + /* RFC 7323 2.3 + * The window field (SEG.WND) of every outgoing segment, with the + * exception of <SYN> segments, MUST be right-shifted by + * Rcv.Wind.Shift bits: + */ tcp_v4_send_ack(sock_net(sk), skb, seq, - tcp_rsk(req)->rcv_nxt, req->rcv_wnd, + tcp_rsk(req)->rcv_nxt, + req->rcv_wnd >> inet_rsk(req)->rcv_wscale, tcp_time_stamp, req->ts_recent, 0, diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 5ed4579f8212..0812b615885d 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -909,8 +909,14 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb) static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, struct request_sock *req) { + /* RFC 7323 2.3 + * The window field (SEG.WND) of every outgoing segment, with the + * exception of <SYN> segments, MUST be right-shifted by + * Rcv.Wind.Shift bits: + */ tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, - req->rcv_wnd, tcp_time_stamp, req->ts_recent, + req->rcv_wnd >> inet_rsk(req)->rcv_wscale, + tcp_time_stamp, req->ts_recent, tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), 0); } |