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authorEric Dumazet <edumazet@google.com>2016-08-22 11:31:10 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-09-30 10:18:34 +0200
commitc867a11289ee74c4594a96ccccac16f4cc29519e (patch)
tree4c6f4ee97cdc896b862beb77e4c898fdf781c53f /net/ipv6/tcp_ipv6.c
parent0f55fa7541d7ff34a6690438bb00b78521b98b54 (diff)
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Diffstat (limited to 'net/ipv6/tcp_ipv6.c')
-rw-r--r--net/ipv6/tcp_ipv6.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 1a1cd3938fd0..2d81e2f33ef2 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -932,9 +932,15 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
* sk->sk_state == TCP_SYN_RECV -> for Fast Open.
*/
+ /* 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(sk, skb, (sk->sk_state == TCP_LISTEN) ?
tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
- tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
+ tcp_rsk(req)->rcv_nxt,
+ req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
0, 0);