[PATCH 35/53] netfilter: tcp: Use TCP_MAX_WSCALE instead of literal 14

[Pablo Neira Ayuso]

From: Gao Feng <f...@ikuai8.com>

The window scale may be enlarged from 14 to 15 according to the itef
draft https://tools.ietf.org/html/draft-nishida-tcpm-maxwin-03.

Use the macro TCP_MAX_WSCALE to support it easily with TCP stack in
the future.

Signed-off-by: Gao Feng <f...@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
 net/netfilter/nf_conntrack_proto_tcp.c | 7 +++----
 net/netfilter/nf_synproxy_core.c       | 4 ++--
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/nf_conntrack_proto_tcp.c 
b/net/netfilter/nf_conntrack_proto_tcp.c
index d0c0a31dfe74..d61a68759dea 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -419,10 +419,9 @@ static void tcp_options(const struct sk_buff *skb,
                                 && opsize == TCPOLEN_WINDOW) {
                                state->td_scale = *(u_int8_t *)ptr;
 
-                               if (state->td_scale > 14) {
-                                       /* See RFC1323 */
-                                       state->td_scale = 14;
-                               }
+                               if (state->td_scale > TCP_MAX_WSCALE)
+                                       state->td_scale = TCP_MAX_WSCALE;
+
                                state->flags |=
                                        IP_CT_TCP_FLAG_WINDOW_SCALE;
                        }
diff --git a/net/netfilter/nf_synproxy_core.c b/net/netfilter/nf_synproxy_core.c
index abe03e869f7b..a504e87c6ddf 100644
--- a/net/netfilter/nf_synproxy_core.c
+++ b/net/netfilter/nf_synproxy_core.c
@@ -66,8 +66,8 @@ synproxy_parse_options(const struct sk_buff *skb, unsigned 
int doff,
                        case TCPOPT_WINDOW:
                                if (opsize == TCPOLEN_WINDOW) {
                                        opts->wscale = *ptr;
-                                       if (opts->wscale > 14)
-                                               opts->wscale = 14;
+                                       if (opts->wscale > TCP_MAX_WSCALE)
+                                               opts->wscale = TCP_MAX_WSCALE;
                                        opts->options |= XT_SYNPROXY_OPT_WSCALE;
                                }
                                break;
-- 
2.1.4