6 files changed, 13 insertions, 10 deletions

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index eeecb8547a2a..32d7d77b4a01 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -81,6 +81,12 @@ enum {
         TCP_DATA_OFFSET = __cpu_to_be32(0xF0000000)
 }; 
 
+/*
+ * TCP general constants
+ */
+#define TCP_MSS_DEFAULT          536U   /* IPv4 (RFC1122, RFC2581) */
+#define TCP_MSS_DESIRED         1220U   /* IPv6 (tunneled), EDNS0 (RFC3226) */
+
 /* TCP socket options */
 #define TCP_NODELAY             1       /* Turn off Nagle's algorithm. */
 #define TCP_MAXSEG              2       /* Limit MSS */
diff --git a/include/net/tcp.h b/include/net/tcp.h
index bf20f88fd033..325bfcf5c934 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -62,9 +62,6 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo);
 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
 #define TCP_MIN_MSS             88U
 
-/* Minimal RCV_MSS. */
-#define TCP_MIN_RCVMSS          536U
-
 /* The least MTU to use for probing */
 #define TCP_BASE_MSS            512
 
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index be0c5bf7bfca..cc306ac6eb51 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -140,7 +140,7 @@ static void tcp_measure_rcv_mss(struct sock *sk, const struct sk_buff *skb)
                  * "len" is invariant segment length, including TCP header.
                  */
                 len += skb->data - skb_transport_header(skb);
-                if (len >= TCP_MIN_RCVMSS + sizeof(struct tcphdr) ||
+                if (len >= TCP_MSS_DEFAULT + sizeof(struct tcphdr) ||
                     /* If PSH is not set, packet should be
                      * full sized, provided peer TCP is not badly broken.
                      * This observation (if it is correct 8)) allows
@@ -411,7 +411,7 @@ void tcp_initialize_rcv_mss(struct sock *sk)
         unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache);
 
         hint = min(hint, tp->rcv_wnd / 2);
-        hint = min(hint, TCP_MIN_RCVMSS);
+        hint = min(hint, TCP_MSS_DEFAULT);
         hint = max(hint, TCP_MIN_MSS);
 
         inet_csk(sk)->icsk_ack.rcv_mss = hint;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 657ae334f125..cf7f2086e6e0 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -217,7 +217,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
         if (inet->opt)
                 inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
 
-        tp->rx_opt.mss_clamp = 536;
+        tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
 
         /* Socket identity is still unknown (sport may be zero).
          * However we set state to SYN-SENT and not releasing socket
@@ -1268,7 +1268,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
                 goto drop_and_free;
 
         tcp_clear_options(&tmp_opt);
-        tmp_opt.mss_clamp = 536;
+        tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
         tmp_opt.user_mss  = tcp_sk(sk)->rx_opt.user_mss;
 
         tcp_parse_options(skb, &tmp_opt, 0, dst);
@@ -1815,7 +1815,7 @@ static int tcp_v4_init_sock(struct sock *sk)
          */
         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
         tp->snd_cwnd_clamp = ~0;
-        tp->mss_cache = 536;
+        tp->mss_cache = TCP_MSS_DEFAULT;
 
         tp->reordering = sysctl_tcp_reordering;
         icsk->icsk_ca_ops = &tcp_init_congestion_ops;
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index a9d34e224cb6..4be22280e6b3 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -476,7 +476,7 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req,
                 if (newtp->af_specific->md5_lookup(sk, newsk))
                         newtp->tcp_header_len += TCPOLEN_MD5SIG_ALIGNED;
 #endif
-                if (skb->len >= TCP_MIN_RCVMSS+newtp->tcp_header_len)
+                if (skb->len >= TCP_MSS_DEFAULT + newtp->tcp_header_len)
                         newicsk->icsk_ack.last_seg_size = skb->len - newtp->tcp_header_len;
                 newtp->rx_opt.mss_clamp = req->mss;
                 TCP_ECN_openreq_child(newtp, req);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 696a22f034e8..de709091b26d 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1851,7 +1851,7 @@ static int tcp_v6_init_sock(struct sock *sk)
          */
         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
         tp->snd_cwnd_clamp = ~0;
-        tp->mss_cache = 536;
+        tp->mss_cache = TCP_MSS_DEFAULT;
 
         tp->reordering = sysctl_tcp_reordering;