[PATCH net-next 7/8] tcp6: Support for TOU

[Tom Herbert]

Need to adjust MSS to account for encapsulation overhead. This is done
by add encpasulation header length into icsk_ext_hdr_len.

Signed-off-by: Tom Herbert <t...@herbertland.com>
---
 net/ipv6/tcp_ipv6.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index f36c2d0..eb67da7 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -62,6 +62,7 @@
 #include <net/inet_common.h>
 #include <net/secure_seq.h>
 #include <net/busy_poll.h>
+#include <net/tou.h>
 
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
@@ -210,7 +211,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr 
*uaddr,
                err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 
                if (err) {
-                       icsk->icsk_ext_hdr_len = exthdrlen;
+                       icsk->icsk_ext_hdr_len = tou_hdr_len(sk) + exthdrlen;
                        icsk->icsk_af_ops = &ipv6_specific;
                        sk->sk_backlog_rcv = tcp_v6_do_rcv;
 #ifdef CONFIG_TCP_MD5SIG
@@ -262,9 +263,9 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr 
*uaddr,
            ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr))
                tcp_fetch_timewait_stamp(sk, dst);
 
-       icsk->icsk_ext_hdr_len = 0;
+       icsk->icsk_ext_hdr_len = tou_hdr_len(sk);
        if (opt)
-               icsk->icsk_ext_hdr_len = opt->opt_flen +
+               icsk->icsk_ext_hdr_len += opt->opt_flen +
                                         opt->opt_nflen;
 
        tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - 
sizeof(struct ipv6hdr);
@@ -1114,9 +1115,9 @@ static struct sock *tcp_v6_syn_recv_sock(const struct 
sock *sk, struct sk_buff *
                opt = ipv6_dup_options(newsk, opt);
                RCU_INIT_POINTER(newnp->opt, opt);
        }
-       inet_csk(newsk)->icsk_ext_hdr_len = 0;
+       inet_csk(newsk)->icsk_ext_hdr_len = tou_hdr_len(sk);
        if (opt)
-               inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
+               inet_csk(newsk)->icsk_ext_hdr_len += opt->opt_nflen +
                                                    opt->opt_flen;
 
        tcp_ca_openreq_child(newsk, dst);
-- 
2.8.0.rc2