3 files changed, 27 insertions, 18 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 3a35b1500359..36c5084964cd 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -490,17 +490,16 @@ u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th,
                               u16 *mssp);
 __u32 cookie_v4_init_sequence(struct sock *sk, const struct sk_buff *skb,
                               __u16 *mss);
-#endif
-
 __u32 cookie_init_timestamp(struct request_sock *req);
-bool cookie_check_timestamp(struct tcp_options_received *opt, struct net *net,
-                            bool *ecn_ok);
+bool cookie_timestamp_decode(struct tcp_options_received *opt);
+bool cookie_ecn_ok(const struct tcp_options_received *opt,
+                   const struct net *net);
 
 /* From net/ipv6/syncookies.c */
 int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th,
                       u32 cookie);
 struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
-#ifdef CONFIG_SYN_COOKIES
+
 u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph,
                               const struct tcphdr *th, u16 *mssp);
 __u32 cookie_v6_init_sequence(struct sock *sk, const struct sk_buff *skb,
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index c3792c0557dd..6de772500ee9 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -241,10 +241,10 @@ static inline struct sock *get_cookie_sock(struct sock *sk, struct sk_buff *skb,
  * additional tcp options in the timestamp.
  * This extracts these options from the timestamp echo.
  *
- * return false if we decode an option that should not be.
+ * return false if we decode a tcp option that is disabled
+ * on the host.
  */
-bool cookie_check_timestamp(struct tcp_options_received *tcp_opt,
-                        struct net *net, bool *ecn_ok)
+bool cookie_timestamp_decode(struct tcp_options_received *tcp_opt)
 {
         /* echoed timestamp, lowest bits contain options */
         u32 options = tcp_opt->rcv_tsecr;
@@ -258,9 +258,6 @@ bool cookie_check_timestamp(struct tcp_options_received *tcp_opt,
                 return false;
 
         tcp_opt->sack_ok = (options & TS_OPT_SACK) ? TCP_SACK_SEEN : 0;
-        *ecn_ok = options & TS_OPT_ECN;
-        if (*ecn_ok && !net->ipv4.sysctl_tcp_ecn)
-                return false;
 
         if (tcp_opt->sack_ok && !sysctl_tcp_sack)
                 return false;
@@ -273,7 +270,22 @@ bool cookie_check_timestamp(struct tcp_options_received *tcp_opt,
 
         return sysctl_tcp_window_scaling != 0;
 }
-EXPORT_SYMBOL(cookie_check_timestamp);
+EXPORT_SYMBOL(cookie_timestamp_decode);
+
+bool cookie_ecn_ok(const struct tcp_options_received *tcp_opt,
+                   const struct net *net)
+{
+        bool ecn_ok = tcp_opt->rcv_tsecr & TS_OPT_ECN;
+
+        if (!ecn_ok)
+                return false;
+
+        if (net->ipv4.sysctl_tcp_ecn)
+                return true;
+
+        return false;
+}
+EXPORT_SYMBOL(cookie_ecn_ok);
 
 struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
 {
@@ -289,7 +301,6 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
         int mss;
         struct rtable *rt;
         __u8 rcv_wscale;
-        bool ecn_ok = false;
         struct flowi4 fl4;
 
         if (!sysctl_tcp_syncookies || !th->ack || th->rst)
@@ -310,7 +321,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
         memset(&tcp_opt, 0, sizeof(tcp_opt));
         tcp_parse_options(skb, &tcp_opt, 0, NULL);
 
-        if (!cookie_check_timestamp(&tcp_opt, sock_net(sk), &ecn_ok))
+        if (!cookie_timestamp_decode(&tcp_opt))
                 goto out;
 
         ret = NULL;
@@ -328,7 +339,6 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
         ireq->ir_loc_addr       = ip_hdr(skb)->daddr;
         ireq->ir_rmt_addr       = ip_hdr(skb)->saddr;
         ireq->ir_mark           = inet_request_mark(sk, skb);
-        ireq->ecn_ok            = ecn_ok;
         ireq->snd_wscale        = tcp_opt.snd_wscale;
         ireq->sack_ok           = tcp_opt.sack_ok;
         ireq->wscale_ok         = tcp_opt.wscale_ok;
@@ -377,6 +387,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
                                   dst_metric(&rt->dst, RTAX_INITRWND));
 
         ireq->rcv_wscale  = rcv_wscale;
+        ireq->ecn_ok = cookie_ecn_ok(&tcp_opt, sock_net(sk));
 
         ret = get_cookie_sock(sk, skb, req, &rt->dst);
         /* ip_queue_xmit() depends on our flow being setup
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index be291baa2ec2..52cc8cb02c0c 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -166,7 +166,6 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
         int mss;
         struct dst_entry *dst;
         __u8 rcv_wscale;
-        bool ecn_ok = false;
 
         if (!sysctl_tcp_syncookies || !th->ack || th->rst)
                 goto out;
@@ -186,7 +185,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
         memset(&tcp_opt, 0, sizeof(tcp_opt));
         tcp_parse_options(skb, &tcp_opt, 0, NULL);
 
-        if (!cookie_check_timestamp(&tcp_opt, sock_net(sk), &ecn_ok))
+        if (!cookie_timestamp_decode(&tcp_opt))
                 goto out;
 
         ret = NULL;
@@ -223,7 +222,6 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
 
         req->expires = 0UL;
         req->num_retrans = 0;
-        ireq->ecn_ok            = ecn_ok;
         ireq->snd_wscale        = tcp_opt.snd_wscale;
         ireq->sack_ok           = tcp_opt.sack_ok;
         ireq->wscale_ok         = tcp_opt.wscale_ok;
@@ -264,6 +262,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
                                   dst_metric(dst, RTAX_INITRWND));
 
         ireq->rcv_wscale = rcv_wscale;
+        ireq->ecn_ok = cookie_ecn_ok(&tcp_opt, sock_net(sk));
 
         ret = get_cookie_sock(sk, skb, req, dst);
 out: