tcpdump/print-geonet.c
Denis Ovsienko 8a33890bba GeoNet: Modernize packet parsing style.
Enable ND_LONGJMP_FROM_TCHECK, lose a few single-use variables, print
one field at a time when possible and remove TCHECK*() instances that
are redundant. The only value print_long_pos_vector() could return was
0, so just make it void. In geonet_print() use nd_print_invalid() and
print the reason for declaring a packet invalid. Update comments and a
test.
2020-10-12 16:48:52 +01:00

267 lines
6.5 KiB
C

/*
* Copyright (c) 2013 The TCPDUMP project
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code
* distributions retain the above copyright notice and this paragraph
* in its entirety, and (2) distributions including binary code include
* the above copyright notice and this paragraph in its entirety in
* the documentation or other materials provided with the distribution.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND
* WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
* LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE.
*
* Original code by Ola Martin Lykkja (ola.lykkja@q-free.com)
*/
/* \summary: ISO CALM FAST and ETSI GeoNetworking printer */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "netdissect-stdinc.h"
#define ND_LONGJMP_FROM_TCHECK
#include "netdissect.h"
#include "extract.h"
#include "addrtoname.h"
/*
ETSI TS 102 636-5-1 V1.1.1 (2011-02)
Intelligent Transport Systems (ITS); Vehicular Communications; GeoNetworking;
Part 5: Transport Protocols; Sub-part 1: Basic Transport Protocol
ETSI TS 102 636-4-1 V1.1.1 (2011-06)
Intelligent Transport Systems (ITS); Vehicular communications; GeoNetworking;
Part 4: Geographical addressing and forwarding for point-to-point and point-to-multipoint communications;
Sub-part 1: Media-Independent Functionality
*/
#define GEONET_ADDR_LEN 8
static const struct tok msg_type_values[] = {
{ 0, "CAM" },
{ 1, "DENM" },
{ 101, "TPEGM" },
{ 102, "TSPDM" },
{ 103, "VPM" },
{ 104, "SRM" },
{ 105, "SLAM" },
{ 106, "ecoCAM" },
{ 107, "ITM" },
{ 150, "SA" },
{ 0, NULL }
};
static void
print_btp_body(netdissect_options *ndo,
const u_char *bp)
{
u_int msg_type;
/* Assuming ItsPduHeader */
ND_PRINT("; ItsPduHeader v:%u", GET_U_1(bp));
msg_type = GET_U_1(bp + 1);
ND_PRINT(" t:%u-%s", msg_type,
tok2str(msg_type_values, "unknown (%u)", msg_type));
}
/* EN 302 636-5-1 V2.2.1 Section 7.2: BTP-A header */
static void
print_btp(netdissect_options *ndo,
const u_char *bp)
{
ND_PRINT("; BTP Dst:%u", GET_BE_U_2(bp + 0));
ND_PRINT(" Src:%u", GET_BE_U_2(bp + 2));
}
static void
print_long_pos_vector(netdissect_options *ndo,
const u_char *bp)
{
ND_PRINT("GN_ADDR:%s ", GET_LINKADDR_STRING(bp, LINKADDR_OTHER, GEONET_ADDR_LEN));
ND_PRINT("lat:%u ", GET_BE_U_4(bp + 12));
ND_PRINT("lon:%u", GET_BE_U_4(bp + 16));
}
/*
* This is the top level routine of the printer. 'p' points
* to the geonet header of the packet.
*/
void
geonet_print(netdissect_options *ndo, const u_char *bp, u_int length,
const struct lladdr_info *src)
{
u_int version;
u_int next_hdr;
u_int hdr_type;
u_int hdr_subtype;
uint16_t payload_length;
u_int hop_limit;
const char *next_hdr_txt = "Unknown";
const char *hdr_type_txt = "Unknown";
int hdr_size = -1;
ndo->ndo_protocol = "geonet";
ND_PRINT("GeoNet ");
if (src != NULL)
ND_PRINT("src:%s", (src->addr_string)(ndo, src->addr));
ND_PRINT("; ");
/* Process Common Header */
if (length < 36) {
ND_PRINT(" (common header length %u < 36)", length);
goto invalid;
}
version = GET_U_1(bp) >> 4;
next_hdr = GET_U_1(bp) & 0x0f;
hdr_type = GET_U_1(bp + 1) >> 4;
hdr_subtype = GET_U_1(bp + 1) & 0x0f;
payload_length = GET_BE_U_2(bp + 4);
hop_limit = GET_U_1(bp + 7);
switch (next_hdr) {
case 0: next_hdr_txt = "Any"; break;
case 1: next_hdr_txt = "BTP-A"; break;
case 2: next_hdr_txt = "BTP-B"; break;
case 3: next_hdr_txt = "IPv6"; break;
}
switch (hdr_type) {
case 0: hdr_type_txt = "Any"; break;
case 1: hdr_type_txt = "Beacon"; break;
case 2: hdr_type_txt = "GeoUnicast"; break;
case 3: switch (hdr_subtype) {
case 0: hdr_type_txt = "GeoAnycastCircle"; break;
case 1: hdr_type_txt = "GeoAnycastRect"; break;
case 2: hdr_type_txt = "GeoAnycastElipse"; break;
}
break;
case 4: switch (hdr_subtype) {
case 0: hdr_type_txt = "GeoBroadcastCircle"; break;
case 1: hdr_type_txt = "GeoBroadcastRect"; break;
case 2: hdr_type_txt = "GeoBroadcastElipse"; break;
}
break;
case 5: switch (hdr_subtype) {
case 0: hdr_type_txt = "TopoScopeBcast-SH"; break;
case 1: hdr_type_txt = "TopoScopeBcast-MH"; break;
}
break;
case 6: switch (hdr_subtype) {
case 0: hdr_type_txt = "LocService-Request"; break;
case 1: hdr_type_txt = "LocService-Reply"; break;
}
break;
}
ND_PRINT("v:%u ", version);
ND_PRINT("NH:%u-%s ", next_hdr, next_hdr_txt);
ND_PRINT("HT:%u-%u-%s ", hdr_type, hdr_subtype, hdr_type_txt);
ND_PRINT("HopLim:%u ", hop_limit);
ND_PRINT("Payload:%u ", payload_length);
print_long_pos_vector(ndo, bp + 8);
/* Skip Common Header */
length -= 36;
bp += 36;
/* Process Extended Headers */
switch (hdr_type) {
case 0: /* Any */
hdr_size = 0;
break;
case 1: /* Beacon */
hdr_size = 0;
break;
case 2: /* GeoUnicast */
break;
case 3: switch (hdr_subtype) {
case 0: /* GeoAnycastCircle */
break;
case 1: /* GeoAnycastRect */
break;
case 2: /* GeoAnycastElipse */
break;
}
break;
case 4: switch (hdr_subtype) {
case 0: /* GeoBroadcastCircle */
break;
case 1: /* GeoBroadcastRect */
break;
case 2: /* GeoBroadcastElipse */
break;
}
break;
case 5: switch (hdr_subtype) {
case 0: /* TopoScopeBcast-SH */
hdr_size = 0;
break;
case 1: /* TopoScopeBcast-MH */
hdr_size = 68 - 36;
break;
}
break;
case 6: switch (hdr_subtype) {
case 0: /* LocService-Request */
break;
case 1: /* LocService-Reply */
break;
}
break;
}
/* Skip Extended headers */
if (hdr_size >= 0) {
if (length < (u_int)hdr_size) {
ND_PRINT(" (header size %d > %u)", hdr_size, length);
goto invalid;
}
ND_TCHECK_LEN(bp, hdr_size);
length -= hdr_size;
bp += hdr_size;
switch (next_hdr) {
case 0: /* Any */
break;
case 1:
case 2: /* BTP A/B */
if (length < 4) {
ND_PRINT(" (BTP length %u < 4)", length);
goto invalid;
}
print_btp(ndo, bp);
length -= 4;
bp += 4;
if (length >= 2) {
/*
* XXX - did print_btp_body()
* return if length < 2
* because this is optional,
* or was that just not
* reporting genuine errors?
*/
print_btp_body(ndo, bp);
}
break;
case 3: /* IPv6 */
break;
}
}
/* Print user data part */
if (ndo->ndo_vflag)
ND_DEFAULTPRINT(bp, length);
return;
invalid:
nd_print_invalid(ndo);
/* XXX - print the remaining data as hex? */
}