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from Yaniv Kaul: add a Preference setting for IP checksum validation 

svn path=/trunk/; revision=16080
This commit is contained in:
Ulf Lamping 2005-10-03 16:24:43 +00:00
parent 376e1adf58
commit 2ee44b8409
1 changed files with 44 additions and 35 deletions
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79
epan/dissectors/packet-ip.c
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@ -72,6 +72,9 @@ static gboolean ip_summary_in_tree = TRUE;
if the packet in the payload has more than 128 bytes */
static gboolean favor_icmp_mpls_ext = FALSE;
/* Perform IP checksum */
static gboolean ip_check_checksum = TRUE;
static int proto_ip = -1;
static int hf_ip_version = -1;
static int hf_ip_hdr_len = -1;
@ -375,9 +378,6 @@ capture_ip(const guchar *pd, int offset, int len, packet_counts *ld) {
return;
}
switch (pd[offset + 9]) {
case IP_PROTO_SCTP:
ld->sctp++;
break;
case IP_PROTO_TCP:
ld->tcp++;
break;
@ -388,6 +388,9 @@ capture_ip(const guchar *pd, int offset, int len, packet_counts *ld) {
case IP_PROTO_ICMPV6: /* XXX - separate counters? */
ld->icmp++;
break;
case IP_PROTO_SCTP:
ld->sctp++;
break;
case IP_PROTO_OSPF:
ld->ospf++;
break;
@ -912,7 +915,7 @@ dissect_ip(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
}
if (tree) {
proto_tree_add_uint_format(ip_tree, hf_ip_hdr_len, tvb, offset, 1, hlen,
proto_tree_add_uint_format(ip_tree, hf_ip_hdr_len, tvb, offset, 1, hlen,
"Header length: %u bytes", hlen);
}
@ -965,11 +968,11 @@ dissect_ip(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
goto end_of_ip;
}
if (tree)
proto_tree_add_uint(ip_tree, hf_ip_len, tvb, offset + 2, 2, iph->ip_len);
proto_tree_add_uint(ip_tree, hf_ip_len, tvb, offset + 2, 2, iph->ip_len);
iph->ip_id = tvb_get_ntohs(tvb, offset + 4);
if (tree)
proto_tree_add_uint(ip_tree, hf_ip_id, tvb, offset + 4, 2, iph->ip_id);
proto_tree_add_uint(ip_tree, hf_ip_id, tvb, offset + 4, 2, iph->ip_id);
iph->ip_off = tvb_get_ntohs(tvb, offset + 6);
if (tree) {
@ -1000,38 +1003,40 @@ dissect_ip(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
/*
* If we have the entire IP header available, check the checksum.
*/
if (tvb_bytes_exist(tvb, offset, hlen)) {
if (ip_check_checksum && tvb_bytes_exist(tvb, offset, hlen)) {
ipsum = ip_checksum(tvb_get_ptr(tvb, offset, hlen), hlen);
if (tree) {
if (ipsum == 0) {
item = proto_tree_add_uint_format(ip_tree, hf_ip_checksum, tvb, offset + 10, 2, iph->ip_sum,
"Header checksum: 0x%04x [correct]", iph->ip_sum);
checksum_tree = proto_item_add_subtree(item, ett_ip_checksum);
item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_good, tvb, offset + 10, 2, TRUE);
PROTO_ITEM_SET_GENERATED(item);
item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_bad, tvb, offset + 10, 2, FALSE);
PROTO_ITEM_SET_GENERATED(item);
} else {
item = proto_tree_add_uint_format(ip_tree, hf_ip_checksum, tvb, offset + 10, 2, iph->ip_sum,
"Header checksum: 0x%04x [incorrect, should be 0x%04x]", iph->ip_sum,
in_cksum_shouldbe(iph->ip_sum, ipsum));
checksum_tree = proto_item_add_subtree(item, ett_ip_checksum);
item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_good, tvb, offset + 10, 2, FALSE);
PROTO_ITEM_SET_GENERATED(item);
item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_bad, tvb, offset + 10, 2, TRUE);
PROTO_ITEM_SET_GENERATED(item);
}
if (tree) {
if (ipsum == 0) {
item = proto_tree_add_uint_format(ip_tree, hf_ip_checksum, tvb, offset + 10, 2, iph->ip_sum,
"Header checksum: 0x%04x [correct]", iph->ip_sum);
checksum_tree = proto_item_add_subtree(item, ett_ip_checksum);
item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_good, tvb, offset + 10, 2, TRUE);
PROTO_ITEM_SET_GENERATED(item);
item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_bad, tvb, offset + 10, 2, FALSE);
PROTO_ITEM_SET_GENERATED(item);
} else {
item = proto_tree_add_uint_format(ip_tree, hf_ip_checksum, tvb, offset + 10, 2, iph->ip_sum,
"Header checksum: 0x%04x [incorrect, should be 0x%04x]", iph->ip_sum,
in_cksum_shouldbe(iph->ip_sum, ipsum));
checksum_tree = proto_item_add_subtree(item, ett_ip_checksum);
item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_good, tvb, offset + 10, 2, FALSE);
PROTO_ITEM_SET_GENERATED(item);
item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_bad, tvb, offset + 10, 2, TRUE);
PROTO_ITEM_SET_GENERATED(item);
}
}
} else {
} else {
ipsum = 0;
if (tree) {
item = proto_tree_add_uint(ip_tree, hf_ip_checksum, tvb, offset + 10, 2, iph->ip_sum);
checksum_tree = proto_item_add_subtree(item, ett_ip_checksum);
item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_good, tvb, offset + 10, 2, FALSE);
PROTO_ITEM_SET_GENERATED(item);
item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_bad, tvb, offset + 10, 2, FALSE);
PROTO_ITEM_SET_GENERATED(item);
}
item = proto_tree_add_uint_format(ip_tree, hf_ip_checksum, tvb, offset + 10, 2, iph->ip_sum,
"Header checksum: 0x%04x [%s]", iph->ip_sum,
ip_check_checksum ? "not all data available" : "validation disabled");
checksum_tree = proto_item_add_subtree(item, ett_ip_checksum);
item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_good, tvb, offset + 10, 2, FALSE);
PROTO_ITEM_SET_GENERATED(item);
item = proto_tree_add_boolean(checksum_tree, hf_ip_checksum_bad, tvb, offset + 10, 2, FALSE);
PROTO_ITEM_SET_GENERATED(item);
}
}
src_addr = tvb_get_ptr(tvb, offset + IPH_SRC, 4);
src32 = tvb_get_ntohl(tvb, offset + IPH_SRC);
@ -1109,7 +1114,7 @@ dissect_ip(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
if (ip_defragment && (iph->ip_off & (IP_MF|IP_OFFSET)) &&
tvb_bytes_exist(tvb, offset, pinfo->iplen - pinfo->iphdrlen) &&
ipsum == 0) {
ipfd_head = fragment_add_check(tvb, offset, pinfo,
ipfd_head = fragment_add_check(tvb, offset, pinfo,
iph->ip_id ^ src32 ^ dst32,
ip_fragment_table,
ip_reassembled_table,
@ -2137,6 +2142,10 @@ proto_register_ip(void)
"Show IP summary in protocol tree",
"Whether the IP summary line should be shown in the protocol tree",
&ip_summary_in_tree);
prefs_register_bool_preference(ip_module, "check_checksum" ,
"Validate the IP checksum if possible",
"Whether to validate the IP checksum",
&ip_check_checksum);
register_dissector("ip", dissect_ip, proto_ip);
register_init_routine(ip_defragment_init);