netfilter: conntrack: move synack init code to helper

It seems more readable to use a common helper in the followup fix rather
than copypaste or goto.

No functional change intended.  The function is only called for syn-ack
or syn in repy direction in case of simultaneous open.

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index af5115e..88c89e9 100644 (file)
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -446,6 +446,32 @@ static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
        }
 }
 
+static void tcp_init_sender(struct ip_ct_tcp_state *sender,
+                           struct ip_ct_tcp_state *receiver,
+                           const struct sk_buff *skb,
+                           unsigned int dataoff,
+                           const struct tcphdr *tcph,
+                           u32 end, u32 win)
+{
+       /* SYN-ACK in reply to a SYN
+        * or SYN from reply direction in simultaneous open.
+        */
+       sender->td_end =
+       sender->td_maxend = end;
+       sender->td_maxwin = (win == 0 ? 1 : win);
+
+       tcp_options(skb, dataoff, tcph, sender);
+       /* RFC 1323:
+        * Both sides must send the Window Scale option
+        * to enable window scaling in either direction.
+        */
+       if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE &&
+             receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE)) {
+               sender->td_scale = 0;
+               receiver->td_scale = 0;
+       }
+}
+
 static bool tcp_in_window(struct nf_conn *ct,
                          enum ip_conntrack_dir dir,
                          unsigned int index,
@@ -499,24 +525,9 @@ static bool tcp_in_window(struct nf_conn *ct,
                 * Initialize sender data.
                 */
                if (tcph->syn) {
-                       /*
-                        * SYN-ACK in reply to a SYN
-                        * or SYN from reply direction in simultaneous open.
-                        */
-                       sender->td_end =
-                       sender->td_maxend = end;
-                       sender->td_maxwin = (win == 0 ? 1 : win);
-
-                       tcp_options(skb, dataoff, tcph, sender);
-                       /*
-                        * RFC 1323:
-                        * Both sides must send the Window Scale option
-                        * to enable window scaling in either direction.
-                        */
-                       if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE
-                             && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE))
-                               sender->td_scale =
-                               receiver->td_scale = 0;
+                       tcp_init_sender(sender, receiver,
+                                       skb, dataoff, tcph,
+                                       end, win);
                        if (!tcph->ack)
                                /* Simultaneous open */
                                return true;