diff options
| author |   markus <markus@openbsd.org> | 2005-06-30 08:51:31 +0000 |
|---|---|---|
| committer | markus <markus@openbsd.org> | 2005-06-30 08:51:31 +0000 |
| commit | 4063babe5e03db10ea5cd68571b7c361bfdc0eed (patch) | |
| tree | 423419f9731c5a4844c37a59b9d2016d9e60d71a /sys/netinet/tcp_output.c | |
| parent | sort ioctls; (diff) | |
| download | wireguard-openbsd-4063babe5e03db10ea5cd68571b7c361bfdc0eed.tar.xz wireguard-openbsd-4063babe5e03db10ea5cd68571b7c361bfdc0eed.zip | |
implement PMTU checks from
http://www.gont.com.ar/drafts/icmp-attacks-against-tcp.html
i.e. don't act on ICMP-need-frag immediately if adhoc checks on the
advertised mtu fail. the mtu update is delayed until a tcp retransmit
happens. initial patch by Fernando Gont, tested by many.
Diffstat (limited to 'sys/netinet/tcp_output.c')
| -rw-r--r-- | sys/netinet/tcp_output.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c index e19d623de96..d36f60dac3c 100644 --- a/sys/netinet/tcp_output.c +++ b/sys/netinet/tcp_output.c @@ -1,4 +1,4 @@ -/* $OpenBSD: tcp_output.c,v 1.78 2005/05/24 00:02:37 fgont Exp $ */ +/* $OpenBSD: tcp_output.c,v 1.79 2005/06/30 08:51:31 markus Exp $ */ /* $NetBSD: tcp_output.c,v 1.16 1997/06/03 16:17:09 kml Exp $ */ /* @@ -214,7 +214,7 @@ tcp_output(tp) struct mbuf *m; struct tcphdr *th; u_char opt[MAX_TCPOPTLEN]; - unsigned int optlen, hdrlen; + unsigned int optlen, hdrlen, packetlen; int idle, sendalot = 0; #ifdef TCP_SACK int i, sack_rxmit = 0; @@ -1073,6 +1073,7 @@ send: ip = mtod(m, struct ip *); ip->ip_len = htons(m->m_pkthdr.len); + packetlen = m->m_pkthdr.len; ip->ip_ttl = tp->t_inpcb->inp_ip.ip_ttl; ip->ip_tos = tp->t_inpcb->inp_ip.ip_tos; #ifdef TCP_ECN @@ -1095,6 +1096,7 @@ send: ip6 = mtod(m, struct ip6_hdr *); ip6->ip6_plen = m->m_pkthdr.len - sizeof(struct ip6_hdr); + packetlen = m->m_pkthdr.len; ip6->ip6_nxt = IPPROTO_TCP; ip6->ip6_hlim = in6_selecthlim(tp->t_inpcb, NULL); #ifdef TCP_ECN @@ -1147,6 +1149,10 @@ out: return (error); } + + if (packetlen > tp->t_pmtud_mtu_sent) + tp->t_pmtud_mtu_sent = packetlen; + tcpstat.tcps_sndtotal++; if (tp->t_flags & TF_DELACK) tcpstat.tcps_delack++; |