diff options
| author | Guy Harris <guy@alum.mit.edu> | 2000-12-14 21:45:12 +0000 |
|---|---|---|
| committer | Guy Harris <guy@alum.mit.edu> | 2000-12-14 21:45:12 +0000 |
| commit | 4f140107f9b39e820aecf3d5349211543f2e4b20 (patch) | |
| tree | 3de3934e2b7ca66f580d5cdd40bfa7dcadb043f5 /packet-icmpv6.c | |
| parent | d11a675ff5f4f50c6c85859c4fb84551ea21680b (diff) | |
Check the checksum on ICMPv6 packets, if possible.
svn path=/trunk/; revision=2759
Diffstat (limited to 'packet-icmpv6.c')
| -rw-r--r-- | packet-icmpv6.c | 50 |
1 files changed, 45 insertions, 5 deletions
diff --git a/packet-icmpv6.c b/packet-icmpv6.c index 0cc8c9857f..0f390a2f1d 100644 --- a/packet-icmpv6.c +++ b/packet-icmpv6.c @@ -1,7 +1,7 @@ /* packet-icmpv6.c * Routines for ICMPv6 packet disassembly * - * $Id: packet-icmpv6.c,v 1.31 2000/11/19 08:53:57 guy Exp $ + * $Id: packet-icmpv6.c,v 1.32 2000/12/14 21:45:12 guy Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs <gerald@zing.org> @@ -54,6 +54,7 @@ #include "packet-ipv6.h" #include "packet-ip.h" #include "packet-dns.h" +#include "in_cksum.h" #include "resolv.h" #ifndef offsetof @@ -720,12 +721,16 @@ static void dissect_icmpv6(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) { proto_tree *icmp6_tree, *field_tree; - proto_item *ti, *tf = NULL; + proto_item *ti, *tf = NULL; struct icmp6_hdr *dp; struct icmp6_nodeinfo *ni = NULL; char *codename, *typename; char *colcodename, *coltypename; int len; + guint length, reported_length; + vec_t cksum_vec[4]; + guint32 phdr[2]; + guint16 cksum, computed_cksum; OLD_CHECK_DISPLAY_AS_DATA(proto_icmpv6, pd, offset, fd, tree); @@ -923,9 +928,44 @@ dissect_icmpv6(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) dp->icmp6_code, "Code: 0x%02x", dp->icmp6_code); } - proto_tree_add_uint(icmp6_tree, hf_icmpv6_checksum, NullTVB, - offset + offsetof(struct icmp6_hdr, icmp6_cksum), 2, - (guint16)htons(dp->icmp6_cksum)); + cksum = (guint16)htons(dp->icmp6_cksum); + length = pi.captured_len - offset; + reported_length = pi.len - offset; + if (!pi.fragmented && length >= reported_length) { + /* The packet isn't part of a fragmented datagram and isn't + truncated, so we can checksum it. */ + + /* Set up the fields of the pseudo-header. */ + cksum_vec[0].ptr = pi.src.data; + cksum_vec[0].len = pi.src.len; + cksum_vec[1].ptr = pi.dst.data; + cksum_vec[1].len = pi.dst.len; + cksum_vec[2].ptr = (const guint8 *)&phdr; + phdr[0] = htonl(reported_length); + phdr[1] = htonl(IP_PROTO_ICMPV6); + cksum_vec[2].len = 8; + cksum_vec[3].ptr = &pd[offset]; + cksum_vec[3].len = reported_length; + computed_cksum = in_cksum(cksum_vec, 4); + if (computed_cksum == 0) { + proto_tree_add_uint_format(icmp6_tree, hf_icmpv6_checksum, + NullTVB, + offset + offsetof(struct icmp6_hdr, icmp6_cksum), 2, + cksum, + "Checksum: 0x%04x (correct)", cksum); + } else { + proto_tree_add_uint_format(icmp6_tree, hf_icmpv6_checksum, + NullTVB, + offset + offsetof(struct icmp6_hdr, icmp6_cksum), 2, + cksum, + "Checksum: 0x%04x (incorrect, should be 0x%04x)", + cksum, in_cksum_shouldbe(cksum, computed_cksum)); + } + } else { + proto_tree_add_uint(icmp6_tree, hf_icmpv6_checksum, NullTVB, + offset + offsetof(struct icmp6_hdr, icmp6_cksum), 2, + cksum); + } /* decode... */ switch (dp->icmp6_type) { |