diff options
| author | Markus Friedl <markus@cvs.openbsd.org> | 2005-06-30 08:51:32 +0000 |
|---|---|---|
| committer | Markus Friedl <markus@cvs.openbsd.org> | 2005-06-30 08:51:32 +0000 |
| commit | d0da6045c3473c63c2c5ebcb604695383312ac92 (patch) | |
| tree | 47b24d0d2ccf633ec13c5ec6181e8098952eea3e /sys/netinet/tcp_timer.c | |
| parent | 9a113f7cb87a9e2074ec670f5a343663a903c767 (diff) | |
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_timer.c')
| -rw-r--r-- | sys/netinet/tcp_timer.c | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/sys/netinet/tcp_timer.c b/sys/netinet/tcp_timer.c index 0f8c64566f5..d8b603617e8 100644 --- a/sys/netinet/tcp_timer.c +++ b/sys/netinet/tcp_timer.c @@ -1,4 +1,4 @@ -/* $OpenBSD: tcp_timer.c,v 1.36 2004/12/13 12:01:49 espie Exp $ */ +/* $OpenBSD: tcp_timer.c,v 1.37 2005/06/30 08:51:31 markus Exp $ */ /* $NetBSD: tcp_timer.c,v 1.14 1996/02/13 23:44:09 christos Exp $ */ /* @@ -52,6 +52,7 @@ #include <netinet/tcp_timer.h> #include <netinet/tcp_var.h> #include <netinet/ip_icmp.h> +#include <netinet/tcp_seq.h> int tcp_keepidle; int tcp_keepintvl; @@ -202,6 +203,31 @@ tcp_timer_rexmt(void *arg) return; } + if ((tp->t_flags & TF_PMTUD_PEND) && tp->t_inpcb && + SEQ_GEQ(tp->t_pmtud_th_seq, tp->snd_una) && + SEQ_LT(tp->t_pmtud_th_seq, (int)(tp->snd_una + tp->t_maxseg))) { + extern struct sockaddr_in icmpsrc; + struct icmp icmp; + + tp->t_flags &= ~TF_PMTUD_PEND; + + /* XXX create fake icmp message with relevant entries */ + icmp.icmp_nextmtu = tp->t_pmtud_nextmtu; + icmp.icmp_ip.ip_len = tp->t_pmtud_ip_len; + icmp.icmp_ip.ip_hl = tp->t_pmtud_ip_hl; + icmpsrc.sin_addr = tp->t_inpcb->inp_faddr; + icmp_mtudisc(&icmp); + + /* + * Notify all connections to the same peer about + * new mss and trigger retransmit. + */ + in_pcbnotifyall(&tcbtable, sintosa(&icmpsrc), EMSGSIZE, + tcp_mtudisc); + splx(s); + return; + } + #ifdef TCP_SACK tcp_timer_freesack(tp); #endif |