diff options
| author | Jun-ichiro itojun Hagino <itojun@cvs.openbsd.org> | 2004-02-05 04:23:14 +0000 |
|---|---|---|
| committer | Jun-ichiro itojun Hagino <itojun@cvs.openbsd.org> | 2004-02-05 04:23:14 +0000 |
| commit | 4cfc2d1aa1181e9af5ef65dc11ed7db41e5a8726 (patch) | |
| tree | a7b563b12cae4db0c5e04e0bd27747efd802f86e /sys/netinet/tcp_input.c | |
| parent | 3551c1d384fd35f693df733b33154a9bd79d307f (diff) | |
take RFC2460 section 5 last paragraph into consideration when we compute MSS
(if path MTU < 1280, use 1280 as packet size and attach fragment header).
markus ok
Diffstat (limited to 'sys/netinet/tcp_input.c')
| -rw-r--r-- | sys/netinet/tcp_input.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c index 2aae18d0f3f..1d99cc37794 100644 --- a/sys/netinet/tcp_input.c +++ b/sys/netinet/tcp_input.c @@ -1,4 +1,4 @@ -/* $OpenBSD: tcp_input.c,v 1.152 2004/01/31 19:40:09 markus Exp $ */ +/* $OpenBSD: tcp_input.c,v 1.153 2004/02/05 04:23:13 itojun Exp $ */ /* $NetBSD: tcp_input.c,v 1.23 1996/02/13 23:43:44 christos Exp $ */ /* @@ -3001,7 +3001,16 @@ tcp_mss(tp, offer) * One may wish to lower MSS to take into account options, * especially security-related options. */ - mss = rt->rt_rmx.rmx_mtu - iphlen - sizeof(struct tcphdr); + if (tp->pf == AF_INET6 && rt->rt_rmx.rmx_mtu < IPV6_MMTU) { + /* + * RFC2460 section 5, last paragraph: if path MTU is + * smaller than 1280, use 1280 as packet size and + * attach fragment header. + */ + mss = IPV6_MMTU - iphlen - sizeof(struct ip6_frag) - + sizeof(struct tcphdr); + } else + mss = rt->rt_rmx.rmx_mtu - iphlen - sizeof(struct tcphdr); } else #endif /* RTV_MTU */ if (!ifp) @@ -3034,11 +3043,11 @@ tcp_mss(tp, offer) #ifndef INET6 mssopt = ifp->if_mtu - iphlen - sizeof(struct tcphdr); #else - if (tp->pf == AF_INET) - mssopt = ifp->if_mtu - iphlen - sizeof(struct tcphdr); - else + if (tp->pf == AF_INET6) mssopt = IN6_LINKMTU(ifp) - iphlen - sizeof(struct tcphdr); + else + mssopt = ifp->if_mtu - iphlen - sizeof(struct tcphdr); #endif mssopt = max(tcp_mssdflt, mssopt); |