rcv_wscale is a symetric parameter with snd_wscale. Both this parameters are set on a connection handshake.
Without this value a remote window size can not be interpreted correctly, because a value from a packet should be shifted on rcv_wscale. And one more thing is that wscale_ok should be set too. This patch doesn't break a backward compatibility. If someone uses it in a old scheme, a rcv window will be restored with the same bug (rcv_wscale = 0). Cc: David S. Miller <[email protected]> Cc: Alexey Kuznetsov <[email protected]> Cc: James Morris <[email protected]> Cc: Hideaki YOSHIFUJI <[email protected]> Cc: Patrick McHardy <[email protected]> Acked-by: Pavel Emelyanov <[email protected]> Signed-off-by: Andrew Vagin <[email protected]> --- net/ipv4/tcp.c | 20 ++++++++++++++++---- 1 files changed, 16 insertions(+), 4 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index df83d74..ed22cd7 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2348,10 +2348,22 @@ static int tcp_repair_options_est(struct tcp_sock *tp, tp->rx_opt.mss_clamp = opt.opt_val; break; case TCPOPT_WINDOW: - if (opt.opt_val > 14) - return -EFBIG; - - tp->rx_opt.snd_wscale = opt.opt_val; + { + union { + struct { + u16 snd_wscale; + u16 rcv_wscale; + }; + u32 raw; + } val = { .raw = opt.opt_val }; + + if (val.snd_wscale > 14 || val.rcv_wscale > 14) + return -EFBIG; + + tp->rx_opt.snd_wscale = val.snd_wscale; + tp->rx_opt.rcv_wscale = val.rcv_wscale; + tp->rx_opt.wscale_ok = 1; + } break; case TCPOPT_SACK_PERM: if (opt.opt_val != 0) -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
