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LISP: Modernize packet parsing

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Define ND_LONGJMP_FROM_TCHECK and remove a 'trunc' label.
Make a bounds check conditional.
Use ND_ICHECK_U() for a length test.
Fix a bounds check, not invalid, but truncated.
(The bounds check is done by hex_print_with_offset() via hex_print().)
Use ND_TTEST_LEN() instead of testing ndo->ndo_snapend.
Remove an useless variable ('packet_iterator' same as 'bp').

Remove/update some comments.
Fix some indentations.
Remove some extra blank lines.

Update the outputs of two tests accordingly.
This commit is contained in:
Francois-Xavier Le Bail 2024-11-21 13:36:49 +01:00 committed by fxlb
parent ec5170b265
commit 85f1d1ea3b
3 changed files with 33 additions and 48 deletions
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77
print-lisp.c
View File

@ -97,6 +97,8 @@
#include <config.h> #include <config.h>
#include "netdissect-stdinc.h" #include "netdissect-stdinc.h"
#define ND_LONGJMP_FROM_TCHECK
#include "netdissect.h" #include "netdissect.h"
#include "ip.h" #include "ip.h"
@ -105,7 +107,6 @@
#include "extract.h" #include "extract.h"
#include "addrtoname.h" #include "addrtoname.h"
#define IPv4_AFI 1 #define IPv4_AFI 1
#define IPv6_AFI 2 #define IPv6_AFI 2
#define TYPE_INDEX 4 #define TYPE_INDEX 4
@ -239,28 +240,26 @@ lisp_print(netdissect_options *ndo, const u_char *bp, u_int length)
uint16_t packet_offset; uint16_t packet_offset;
uint16_t auth_data_len; uint16_t auth_data_len;
uint32_t ttl; uint32_t ttl;
const u_char *packet_iterator;
const lisp_map_register_hdr *lisp_hdr; const lisp_map_register_hdr *lisp_hdr;
const lisp_map_register_eid *lisp_eid; const lisp_map_register_eid *lisp_eid;
const lisp_map_register_loc *lisp_loc; const lisp_map_register_loc *lisp_loc;
ndo->ndo_protocol = "lisp"; ndo->ndo_protocol = "lisp";
/* Check if enough bytes for header are available */
ND_TCHECK_LEN(bp, MAP_REGISTER_HDR_LEN);
lisp_hdr = (const lisp_map_register_hdr *) bp; lisp_hdr = (const lisp_map_register_hdr *) bp;
lisp_hdr_flag(ndo, lisp_hdr); lisp_hdr_flag(ndo, lisp_hdr);
/* Supporting only MAP NOTIFY and MAP REGISTER LISP packets */ /* Supporting only MAP NOTIFY and MAP REGISTER LISP packets */
type_and_flag = GET_U_1(lisp_hdr->type_and_flag); type_and_flag = GET_U_1(lisp_hdr->type_and_flag);
type = extract_lisp_type(type_and_flag); type = extract_lisp_type(type_and_flag);
if ((type != LISP_MAP_REGISTER) && (type != LISP_MAP_NOTIFY)) if ((type != LISP_MAP_REGISTER) && (type != LISP_MAP_NOTIFY)) {
ND_TCHECK_LEN(bp, MAP_REGISTER_HDR_LEN);
return; return;
}
/* Find if the packet contains xTR and Site-ID data */ /* Find if the packet contains xTR and Site-ID data */
xtr_present = is_xtr_data_present(type, type_and_flag); xtr_present = is_xtr_data_present(type, type_and_flag);
/* Extract the number of EID records present */ /* Extract the number of EID records present */
auth_data_len = GET_BE_U_2(lisp_hdr->auth_data_len); auth_data_len = GET_BE_U_2(lisp_hdr->auth_data_len);
packet_iterator = (const u_char *)(lisp_hdr);
packet_offset = MAP_REGISTER_HDR_LEN; packet_offset = MAP_REGISTER_HDR_LEN;
record_count = GET_U_1(lisp_hdr->record_count); record_count = GET_U_1(lisp_hdr->record_count);
@ -268,25 +267,22 @@ lisp_print(netdissect_options *ndo, const u_char *bp, u_int length)
key_id = GET_BE_U_2(lisp_hdr->key_id); key_id = GET_BE_U_2(lisp_hdr->key_id);
ND_PRINT("\n %u record(s), ", record_count); ND_PRINT("\n %u record(s), ", record_count);
ND_PRINT("Authentication %s,", ND_PRINT("Authentication %s,",
tok2str(auth_type, "unknown-type", key_id)); tok2str(auth_type, "unknown-type", key_id));
hex_print(ndo, "\n Authentication-Data: ", packet_iterator + hex_print(ndo, "\n Authentication-Data: ",
packet_offset, auth_data_len); bp + packet_offset, auth_data_len);
} else { } else {
ND_PRINT(" %u record(s),", record_count); ND_PRINT(" %u record(s),", record_count);
} }
packet_offset += auth_data_len; packet_offset += auth_data_len;
if (record_count == 0) ND_ICHECK_U(record_count, ==, 0);
goto invalid;
/* Print all the EID records */ /* Print all the EID records */
while ((length > packet_offset) && (record_count != 0)) { while ((length > packet_offset) && (record_count != 0)) {
record_count--; record_count--;
ND_TCHECK_LEN(packet_iterator + packet_offset, ND_TCHECK_LEN(bp + packet_offset, MAP_REGISTER_EID_LEN);
MAP_REGISTER_EID_LEN);
ND_PRINT("\n"); ND_PRINT("\n");
lisp_eid = (const lisp_map_register_eid *) lisp_eid = (const lisp_map_register_eid *) (bp + packet_offset);
((const u_char *)lisp_hdr + packet_offset);
packet_offset += MAP_REGISTER_EID_LEN; packet_offset += MAP_REGISTER_EID_LEN;
mask_len = GET_U_1(lisp_eid->eid_prefix_mask_length); mask_len = GET_U_1(lisp_eid->eid_prefix_mask_length);
eid_afi = GET_BE_U_2(lisp_eid->eid_prefix_afi); eid_afi = GET_BE_U_2(lisp_eid->eid_prefix_afi);
@ -303,14 +299,14 @@ lisp_print(netdissect_options *ndo, const u_char *bp, u_int length)
switch (eid_afi) { switch (eid_afi) {
case IPv4_AFI: case IPv4_AFI:
ND_PRINT(" EID %s/%u,", ND_PRINT(" EID %s/%u,",
GET_IPADDR_STRING(packet_iterator + packet_offset), GET_IPADDR_STRING(bp + packet_offset),
mask_len); mask_len);
packet_offset += 4; packet_offset += 4;
break; break;
case IPv6_AFI: case IPv6_AFI:
ND_PRINT(" EID %s/%u,", ND_PRINT(" EID %s/%u,",
GET_IP6ADDR_STRING(packet_iterator + packet_offset), GET_IP6ADDR_STRING(bp + packet_offset),
mask_len); mask_len);
packet_offset += 16; packet_offset += 16;
break; break;
default: default:
@ -324,9 +320,8 @@ lisp_print(netdissect_options *ndo, const u_char *bp, u_int length)
while (loc_count != 0) { while (loc_count != 0) {
loc_count--; loc_count--;
ND_TCHECK_LEN(packet_iterator + packet_offset, ND_TCHECK_LEN(bp + packet_offset, MAP_REGISTER_LOC_LEN);
MAP_REGISTER_LOC_LEN); lisp_loc = (const lisp_map_register_loc *) (bp + packet_offset);
lisp_loc = (const lisp_map_register_loc *) (packet_iterator + packet_offset);
packet_offset += MAP_REGISTER_LOC_LEN; packet_offset += MAP_REGISTER_LOC_LEN;
loc_afi = GET_BE_U_2(lisp_loc->locator_afi); loc_afi = GET_BE_U_2(lisp_loc->locator_afi);
@ -336,14 +331,12 @@ lisp_print(netdissect_options *ndo, const u_char *bp, u_int length)
switch (loc_afi) { switch (loc_afi) {
case IPv4_AFI: case IPv4_AFI:
ND_PRINT(" LOC %s", ND_PRINT(" LOC %s",
GET_IPADDR_STRING(packet_iterator + GET_IPADDR_STRING(bp + packet_offset));
packet_offset));
packet_offset += 4; packet_offset += 4;
break; break;
case IPv6_AFI: case IPv6_AFI:
ND_PRINT(" LOC %s", ND_PRINT(" LOC %s",
GET_IP6ADDR_STRING(packet_iterator + GET_IP6ADDR_STRING(bp + packet_offset));
packet_offset));
packet_offset += 16; packet_offset += 16;
break; break;
default: default:
@ -363,27 +356,23 @@ lisp_print(netdissect_options *ndo, const u_char *bp, u_int length)
} }
/* /*
* Print xTR and Site ID. Handle the fact that the packet could be invalid. * Print xTR and Site ID.
* If the xTR_ID_Present bit is not set, and we still have data to display, * If the xTR_ID_Present bit is not set, and we still have data to
* show it as hex data. * display, show it as hex data.
*/ */
if (xtr_present) { if (xtr_present) {
if (!ND_TTEST_LEN(packet_iterator + packet_offset, 24)) hex_print(ndo, "\n xTR-ID: ", bp + packet_offset, 16);
goto invalid;
hex_print(ndo, "\n xTR-ID: ", packet_iterator + packet_offset, 16);
ND_PRINT("\n SITE-ID: %" PRIu64, ND_PRINT("\n SITE-ID: %" PRIu64,
GET_BE_U_8(packet_iterator + packet_offset + 16)); GET_BE_U_8(bp + packet_offset + 16));
} else { } else {
/* Check if packet isn't over yet */ /* If there's at least one byte to print */
if (packet_iterator + packet_offset < ndo->ndo_snapend) { if (ND_TTEST_LEN(bp + packet_offset, 1)) {
hex_print(ndo, "\n Data: ", packet_iterator + packet_offset, hex_print(ndo, "\n Data: ", bp + packet_offset,
ND_BYTES_AVAILABLE_AFTER(packet_iterator + packet_offset)); ND_BYTES_AVAILABLE_AFTER(bp + packet_offset));
} }
} }
return; return;
trunc:
nd_print_trunc(ndo);
return;
invalid: invalid:
nd_print_invalid(ndo); nd_print_invalid(ndo);
} }
@ -411,12 +400,9 @@ static void lisp_hdr_flag(netdissect_options *ndo, const lisp_map_register_hdr *
{ {
uint8_t type = extract_lisp_type(GET_U_1(lisp_hdr->type_and_flag)); uint8_t type = extract_lisp_type(GET_U_1(lisp_hdr->type_and_flag));
if (!ndo->ndo_vflag) { ND_PRINT("%s,", tok2str(lisp_type, "unknown-type-%u", type));
ND_PRINT("%s,", tok2str(lisp_type, "unknown-type-%u", type)); if (!ndo->ndo_vflag)
return; return;
} else {
ND_PRINT("%s,", tok2str(lisp_type, "unknown-type-%u", type));
}
if (type == LISP_MAP_REGISTER) { if (type == LISP_MAP_REGISTER) {
ND_PRINT(" flags [%s],", bittok2str(map_register_hdr_flag, ND_PRINT(" flags [%s],", bittok2str(map_register_hdr_flag,
@ -447,4 +433,3 @@ static void loc_hdr_flag(netdissect_options *ndo, uint16_t flag)
{ {
ND_PRINT(" flags [%s],", bittok2str(lisp_loc_flag, "none", flag)); ND_PRINT(" flags [%s],", bittok2str(lisp_loc_flag, "none", flag));
} }

2
tests/lisp_eid_notify-v.out
View File

@ -44,7 +44,7 @@
Priority/Weight 1/100, Multicast Priority/Weight 1/100, flags [none], Priority/Weight 1/100, Multicast Priority/Weight 1/100, flags [none],
Record TTL 1440, Authoritative, No-Action, Map Version: 0, EID 10.30.1.80/32, 1 locator(s) Record TTL 1440, Authoritative, No-Action, Map Version: 0, EID 10.30.1.80/32, 1 locator(s)
LOC 20.20.8.239 LOC 20.20.8.239
Priority/Weight 1/100, Multicast Priority/Weight 1/100, flags [none], (invalid) Priority/Weight 1/100, Multicast Priority/Weight 1/100, flags [none], [|lisp]
4 2015-08-22 11:09:07.451778 IP (tos 0x0, ttl 64, id 1, offset 0, flags [none], proto UDP (17), length 156) 4 2015-08-22 11:09:07.451778 IP (tos 0x0, ttl 64, id 1, offset 0, flags [none], proto UDP (17), length 156)
192.168.0.105.4342 > 127.0.0.1.4342: LISP-Map-Notify, flags [none], 192.168.0.105.4342 > 127.0.0.1.4342: LISP-Map-Notify, flags [none],
2 record(s), Authentication SHA1, 2 record(s), Authentication SHA1,

2
tests/lisp_eid_notify.out
View File

@ -10,7 +10,7 @@
3 2015-08-22 11:09:06.507423 IP 192.168.0.105.4342 > 127.0.0.1.4342: LISP-Map-Notify, 3 record(s), 3 2015-08-22 11:09:06.507423 IP 192.168.0.105.4342 > 127.0.0.1.4342: LISP-Map-Notify, 3 record(s),
EID 10.30.1.100/32, 1 locator(s) LOC 20.20.8.253 EID 10.30.1.100/32, 1 locator(s) LOC 20.20.8.253
EID 10.30.1.96/32, 2 locator(s) LOC 20.20.8.251 LOC 20.20.8.252 EID 10.30.1.96/32, 2 locator(s) LOC 20.20.8.251 LOC 20.20.8.252
EID 10.30.1.80/32, 1 locator(s) LOC 20.20.8.239 (invalid) EID 10.30.1.80/32, 1 locator(s) LOC 20.20.8.239 [|lisp]
4 2015-08-22 11:09:07.451778 IP 192.168.0.105.4342 > 127.0.0.1.4342: LISP-Map-Notify, 2 record(s), 4 2015-08-22 11:09:07.451778 IP 192.168.0.105.4342 > 127.0.0.1.4342: LISP-Map-Notify, 2 record(s),
EID 10.30.1.100/32, 1 locator(s) LOC 20.20.8.253 EID 10.30.1.100/32, 1 locator(s) LOC 20.20.8.253
EID 10.30.1.96/32, 2 locator(s) LOC 20.20.8.251 LOC 20.20.8.252 EID 10.30.1.96/32, 2 locator(s) LOC 20.20.8.251 LOC 20.20.8.252