diff options
| author | Ted Lemon <source@isc.org> | 1998-01-12 01:00:42 +0000 |
|---|---|---|
| committer | Ted Lemon <source@isc.org> | 1998-01-12 01:00:42 +0000 |
| commit | 0a8ee595f1df3ae2c43c74f5988f12251561cfa7 (patch) | |
| tree | fd3eebc1eb40838e9ebb3db1cc28650f280b67f3 /common/icmp.c | |
| parent | eb0b66697bec5e5d01692ca12eeb29f9e891619b (diff) | |
| download | isc-dhcp-0a8ee595f1df3ae2c43c74f5988f12251561cfa7.tar.gz | |
Handle ICMP packets with IP header options correctly.
Diffstat (limited to 'common/icmp.c')
| -rw-r--r-- | common/icmp.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/common/icmp.c b/common/icmp.c index 59082842..c3c357c0 100644 --- a/common/icmp.c +++ b/common/icmp.c @@ -43,7 +43,7 @@ #ifndef lint static char copyright[] = -"$Id: icmp.c,v 1.7 1997/06/04 20:59:40 mellon Exp $ Copyright (c) 1997 The Internet Software Consortium. All rights reserved.\n"; +"$Id: icmp.c,v 1.8 1998/01/12 01:00:42 mellon Exp $ Copyright (c) 1997 The Internet Software Consortium. All rights reserved.\n"; #endif /* not lint */ #include "dhcpd.h" @@ -135,10 +135,11 @@ void icmp_echoreply (protocol) struct protocol *protocol; { struct icmp *icfrom; + struct ip *ip; struct sockaddr_in from; unsigned char icbuf [1500]; int status; - int len; + int len, hlen; struct iaddr ia; void (*handler) PROTO ((struct iaddr, u_int8_t *, int)); @@ -150,13 +151,17 @@ void icmp_echoreply (protocol) return; } - /* Probably not for us. */ - if (status < (sizeof (struct ip)) + (sizeof *icfrom)) { + /* Find the IP header length... */ + ip = (struct ip *)icbuf; + hlen = ip -> ip_hl << 2; + + /* Short packet? */ + if (status < hlen + (sizeof *icfrom)) { return; } - len = status - sizeof (struct ip); - icfrom = (struct icmp *)(icbuf + sizeof (struct ip)); + len = status - hlen; + icfrom = (struct icmp *)(icbuf + hlen); /* Silently discard ICMP packets that aren't echoreplies. */ if (icfrom -> icmp_type != ICMP_ECHOREPLY) { |