From 345cda2fd695534be5a4494f1b59da9daed33663 Mon Sep 17 00:00:00 2001 From: Gilad Ben-Yossef Date: Wed, 28 Oct 2009 04:15:26 +0000 Subject: [PATCH] Allow to turn off TCP window scale opt per route Add and use no window scale bit in the features field. Note that this is not the same as setting a window scale of 0 as would happen with window limit on route. Signed-off-by: Gilad Ben-Yossef Sigend-off-by: Ori Finkelman Sigend-off-by: Yony Amit Signed-off-by: David S. Miller --- include/linux/rtnetlink.h | 1 + net/ipv4/tcp_input.c | 3 ++- net/ipv4/tcp_output.c | 6 ++++-- 3 files changed, 7 insertions(+), 3 deletions(-) diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index 2ab8c758b46..6784b342cbb 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -380,6 +380,7 @@ enum #define RTAX_FEATURE_NO_SACK 0x00000002 #define RTAX_FEATURE_NO_TSTAMP 0x00000004 #define RTAX_FEATURE_ALLFRAG 0x00000008 +#define RTAX_FEATURE_NO_WSCALE 0x00000010 struct rta_session { diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 6097491aa9f..393c56921dc 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3739,7 +3739,8 @@ void tcp_parse_options(struct sk_buff *skb, struct tcp_options_received *opt_rx, break; case TCPOPT_WINDOW: if (opsize == TCPOLEN_WINDOW && th->syn && - !estab && sysctl_tcp_window_scaling) { + !estab && sysctl_tcp_window_scaling && + !dst_feature(dst, RTAX_FEATURE_NO_WSCALE)) { __u8 snd_wscale = *(__u8 *)ptr; opt_rx->wscale_ok = 1; if (snd_wscale > 14) { diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 8819eba8ebb..616c686ca25 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -496,7 +496,8 @@ static unsigned tcp_syn_options(struct sock *sk, struct sk_buff *skb, opts->tsecr = tp->rx_opt.ts_recent; size += TCPOLEN_TSTAMP_ALIGNED; } - if (likely(sysctl_tcp_window_scaling)) { + if (likely(sysctl_tcp_window_scaling && + !dst_feature(dst, RTAX_FEATURE_NO_WSCALE))) { opts->ws = tp->rx_opt.rcv_wscale; opts->options |= OPTION_WSCALE; size += TCPOLEN_WSCALE_ALIGNED; @@ -2347,7 +2348,8 @@ static void tcp_connect_init(struct sock *sk) tp->advmss - (tp->rx_opt.ts_recent_stamp ? tp->tcp_header_len - sizeof(struct tcphdr) : 0), &tp->rcv_wnd, &tp->window_clamp, - sysctl_tcp_window_scaling, + (sysctl_tcp_window_scaling && + !dst_feature(dst, RTAX_FEATURE_NO_WSCALE)), &rcv_wscale); tp->rx_opt.rcv_wscale = rcv_wscale; -- 2.41.0