diff options
| -rw-r--r-- | packet-ip.c | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/packet-ip.c b/packet-ip.c index 8058f455dc..7faedf8c80 100644 --- a/packet-ip.c +++ b/packet-ip.c @@ -1,7 +1,7 @@ /* packet-ip.c * Routines for IP and miscellaneous IP protocol packet disassembly * - * $Id: packet-ip.c,v 1.103 2000/09/16 00:48:43 sharpe Exp $ + * $Id: packet-ip.c,v 1.104 2000/10/21 04:34:47 guy Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs <gerald@zing.org> @@ -1008,7 +1008,7 @@ dissect_icmp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) { e_icmp ih; proto_tree *icmp_tree; proto_item *ti; - guint16 cksum; + guint16 cksum, computed_cksum; gchar type_str[64], code_str[64] = ""; guint8 num_addrs = 0; guint8 addr_entry_size = 0; @@ -1020,7 +1020,7 @@ dissect_icmp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) { memcpy(&ih, &pd[offset], sizeof(e_icmp)); /* To do: check for runts, errs, etc. */ cksum = ntohs(ih.icmp_cksum); - + switch (ih.icmp_type) { case ICMP_ECHOREPLY: strcpy(type_str, "Echo (ping) reply"); @@ -1107,8 +1107,30 @@ dissect_icmp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) { ih.icmp_code, "Code: %u %s", ih.icmp_code, code_str); - proto_tree_add_uint(icmp_tree, hf_icmp_checksum, NullTVB, offset + 2, 2, + + if (pi.captured_len >= pi.len) { + /* The packet isn't truncated, so we can checksum it. + XXX - we have to check whether this is part of a fragmented + IP datagram, too.... */ + + computed_cksum = ip_checksum(&pd[offset], END_OF_FRAME); + if (computed_cksum == 0) { + proto_tree_add_uint_format(icmp_tree, hf_icmp_checksum, NullTVB, + offset + 2, 2, + cksum, + "Checksum: 0x%04x (correct)", cksum); + } else { + proto_tree_add_uint_format(icmp_tree, hf_icmp_checksum, NullTVB, + offset + 2, 2, + cksum, + "Checksum: 0x%04x (incorrect, should be 0x%04x)", + cksum, ip_checksum_shouldbe(cksum, computed_cksum)); + } + } else { + proto_tree_add_uint(icmp_tree, hf_icmp_checksum, NullTVB, + offset + 2, 2, cksum); + } /* Decode the second 4 bytes of the packet. */ switch (ih.icmp_type) { |