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tcpdump/print-gre.c
Francois-Xavier Le Bail ef5323efe6 Update the ND_LCHECK*() macros to ND_ICHECK*() macros 
ICHECK like Invalid-Check.
Reminder: If the checked expression is true an error message is printed
and a 'goto invalid' is executed.

This change adds the parameter 'operator'.

Before this change, '<' comparison was hard coded.
We can do now:
ND_ICHECK_U(length, <, HEADER_LEN);
ND_ICHECK_U(length, ==, 24);
ND_ICHECK_U(length, !=, 8);
ND_ICHECK_ZU(length, <, sizeof(struct my_struct));
ND_ICHECKMSG_U("message length", msg_tlen, <, 4);
...
(Any comparison operator)

Remark: The change of names from ND_LCHECK*() to ND_ICHECK*() is
because something else than a length(L) can be checked.

Moreover:
Place the 'message' parameter at the beginning of ND_ICHECKMSG_U()
and ND_ICHECKMSG_ZU() paramaters lists.
2021-12-29 15:11:32 +01:00

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/* $OpenBSD: print-gre.c,v 1.6 2002/10/30 03:04:04 fgsch Exp $ */
/*
* Copyright (c) 2002 Jason L. Wright (jason@thought.net)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/* \summary: Generic Routing Encapsulation (GRE) printer */
/*
* netdissect printer for GRE - Generic Routing Encapsulation
* RFC1701 (GRE), RFC1702 (GRE IPv4), and RFC2637 (Enhanced GRE)
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "netdissect-stdinc.h"
#define ND_LONGJMP_FROM_TCHECK
#include "netdissect.h"
#include "addrtostr.h"
#include "extract.h"
#include "ethertype.h"
#define GRE_CP 0x8000 /* checksum present */
#define GRE_RP 0x4000 /* routing present */
#define GRE_KP 0x2000 /* key present */
#define GRE_SP 0x1000 /* sequence# present */
#define GRE_sP 0x0800 /* source routing */
#define GRE_AP 0x0080 /* acknowledgment# present */
static const struct tok gre_flag_values[] = {
{ GRE_CP, "checksum present"},
{ GRE_RP, "routing present"},
{ GRE_KP, "key present"},
{ GRE_SP, "sequence# present"},
{ GRE_sP, "source routing present"},
{ GRE_AP, "ack present"},
{ 0, NULL }
};
#define GRE_RECRS_MASK 0x0700 /* recursion count */
#define GRE_VERS_MASK 0x0007 /* protocol version */
/* source route entry types */
#define GRESRE_IP 0x0800 /* IP */
#define GRESRE_ASN 0xfffe /* ASN */
static void gre_print_0(netdissect_options *, const u_char *, u_int);
static void gre_print_1(netdissect_options *, const u_char *, u_int);
static int gre_sre_print(netdissect_options *, uint16_t, uint8_t, uint8_t, const u_char *, u_int);
static int gre_sre_ip_print(netdissect_options *, uint8_t, uint8_t, const u_char *, u_int);
static int gre_sre_asn_print(netdissect_options *, uint8_t, uint8_t, const u_char *, u_int);
void
gre_print(netdissect_options *ndo, const u_char *bp, u_int length)
{
u_int vers;
ndo->ndo_protocol = "gre";
nd_print_protocol_caps(ndo);
ND_ICHECK_U(length, <, 2);
vers = GET_BE_U_2(bp) & GRE_VERS_MASK;
ND_PRINT("v%u",vers);
switch(vers) {
case 0:
gre_print_0(ndo, bp, length);
break;
case 1:
gre_print_1(ndo, bp, length);
break;
default:
ND_PRINT(" ERROR: unknown-version");
break;
}
return;
invalid:
nd_print_invalid(ndo);
}
static void
gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
{
u_int len = length;
uint16_t flags, prot;
ND_ICHECK_U(len, <, 2);
flags = GET_BE_U_2(bp);
if (ndo->ndo_vflag)
ND_PRINT(", Flags [%s]",
bittok2str(gre_flag_values,"none",flags));
len -= 2;
bp += 2;
ND_ICHECK_U(len, <, 2);
prot = GET_BE_U_2(bp);
len -= 2;
bp += 2;
if ((flags & GRE_CP) | (flags & GRE_RP)) {
uint16_t sum;
ND_ICHECK_U(len, <, 2);
sum = GET_BE_U_2(bp);
if (ndo->ndo_vflag)
ND_PRINT(", sum 0x%x", sum);
bp += 2;
len -= 2;
ND_ICHECK_U(len, <, 2);
ND_PRINT(", off 0x%x", GET_BE_U_2(bp));
bp += 2;
len -= 2;
}
if (flags & GRE_KP) {
ND_ICHECK_U(len, <, 4);
ND_PRINT(", key=0x%x", GET_BE_U_4(bp));
bp += 4;
len -= 4;
}
if (flags & GRE_SP) {
ND_ICHECK_U(len, <, 4);
ND_PRINT(", seq %u", GET_BE_U_4(bp));
bp += 4;
len -= 4;
}
if (flags & GRE_RP) {
for (;;) {
uint16_t af;
uint8_t sreoff;
uint8_t srelen;
ND_ICHECK_U(len, <, 4);
af = GET_BE_U_2(bp);
sreoff = GET_U_1(bp + 2);
srelen = GET_U_1(bp + 3);
bp += 4;
len -= 4;
if (af == 0 && srelen == 0)
break;
if (!gre_sre_print(ndo, af, sreoff, srelen, bp, len))
goto invalid;
ND_ICHECK_U(len, <, srelen);
bp += srelen;
len -= srelen;
}
}
if (ndo->ndo_eflag)
ND_PRINT(", proto %s (0x%04x)",
tok2str(ethertype_values,"unknown",prot), prot);
ND_PRINT(", length %u",length);
if (ndo->ndo_vflag < 1)
ND_PRINT(": "); /* put in a colon as protocol demarc */
else
ND_PRINT("\n\t"); /* if verbose go multiline */
switch (prot) {
case ETHERTYPE_IP:
ip_print(ndo, bp, len);
break;
case ETHERTYPE_IPV6:
ip6_print(ndo, bp, len);
break;
case ETHERTYPE_MPLS:
mpls_print(ndo, bp, len);
break;
case ETHERTYPE_IPX:
ipx_print(ndo, bp, len);
break;
case ETHERTYPE_ATALK:
atalk_print(ndo, bp, len);
break;
case ETHERTYPE_GRE_ISO:
isoclns_print(ndo, bp, len);
break;
case ETHERTYPE_TEB:
ether_print(ndo, bp, len, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
break;
default:
ND_PRINT("gre-proto-0x%x", prot);
}
return;
invalid:
nd_print_invalid(ndo);
}
static void
gre_print_1(netdissect_options *ndo, const u_char *bp, u_int length)
{
u_int len = length;
uint16_t flags, prot;
ND_ICHECK_U(len, <, 2);
flags = GET_BE_U_2(bp);
len -= 2;
bp += 2;
if (ndo->ndo_vflag)
ND_PRINT(", Flags [%s]",
bittok2str(gre_flag_values,"none",flags));
ND_ICHECK_U(len, <, 2);
prot = GET_BE_U_2(bp);
len -= 2;
bp += 2;
if (flags & GRE_KP) {
uint32_t k;
ND_ICHECK_U(len, <, 4);
k = GET_BE_U_4(bp);
ND_PRINT(", call %u", k & 0xffff);
len -= 4;
bp += 4;
}
if (flags & GRE_SP) {
ND_ICHECK_U(len, <, 4);
ND_PRINT(", seq %u", GET_BE_U_4(bp));
bp += 4;
len -= 4;
}
if (flags & GRE_AP) {
ND_ICHECK_U(len, <, 4);
ND_PRINT(", ack %u", GET_BE_U_4(bp));
bp += 4;
len -= 4;
}
if ((flags & GRE_SP) == 0)
ND_PRINT(", no-payload");
if (ndo->ndo_eflag)
ND_PRINT(", proto %s (0x%04x)",
tok2str(ethertype_values,"unknown",prot), prot);
ND_PRINT(", length %u",length);
if ((flags & GRE_SP) == 0)
return;
if (ndo->ndo_vflag < 1)
ND_PRINT(": "); /* put in a colon as protocol demarc */
else
ND_PRINT("\n\t"); /* if verbose go multiline */
switch (prot) {
case ETHERTYPE_PPP:
ppp_print(ndo, bp, len);
break;
default:
ND_PRINT("gre-proto-0x%x", prot);
break;
}
return;
invalid:
nd_print_invalid(ndo);
}
static int
gre_sre_print(netdissect_options *ndo, uint16_t af, uint8_t sreoff,
uint8_t srelen, const u_char *bp, u_int len)
{
int ret;
switch (af) {
case GRESRE_IP:
ND_PRINT(", (rtaf=ip");
ret = gre_sre_ip_print(ndo, sreoff, srelen, bp, len);
ND_PRINT(")");
break;
case GRESRE_ASN:
ND_PRINT(", (rtaf=asn");
ret = gre_sre_asn_print(ndo, sreoff, srelen, bp, len);
ND_PRINT(")");
break;
default:
ND_PRINT(", (rtaf=0x%x)", af);
ret = 1;
}
return (ret);
}
static int
gre_sre_ip_print(netdissect_options *ndo, uint8_t sreoff, uint8_t srelen,
const u_char *bp, u_int len)
{
const u_char *up = bp;
char buf[INET_ADDRSTRLEN];
if (sreoff & 3) {
ND_PRINT(", badoffset=%u", sreoff);
goto invalid;
}
if (srelen & 3) {
ND_PRINT(", badlength=%u", srelen);
goto invalid;
}
if (sreoff >= srelen) {
ND_PRINT(", badoff/len=%u/%u", sreoff, srelen);
goto invalid;
}
while (srelen != 0) {
ND_ICHECK_U(len, <, 4);
ND_TCHECK_LEN(bp, sizeof(nd_ipv4));
addrtostr(bp, buf, sizeof(buf));
ND_PRINT(" %s%s",
((bp - up) == sreoff) ? "*" : "", buf);
bp += 4;
len -= 4;
srelen -= 4;
}
return 1;
invalid:
return 0;
}
static int
gre_sre_asn_print(netdissect_options *ndo, uint8_t sreoff, uint8_t srelen,
const u_char *bp, u_int len)
{
const u_char *up = bp;
if (sreoff & 1) {
ND_PRINT(", badoffset=%u", sreoff);
goto invalid;
}
if (srelen & 1) {
ND_PRINT(", badlength=%u", srelen);
goto invalid;
}
if (sreoff >= srelen) {
ND_PRINT(", badoff/len=%u/%u", sreoff, srelen);
goto invalid;
}
while (srelen != 0) {
ND_ICHECK_U(len, <, 2);
ND_PRINT(" %s%x",
((bp - up) == sreoff) ? "*" : "", GET_BE_U_2(bp));
bp += 2;
len -= 2;
srelen -= 2;
}
return 1;
invalid:
return 0;
}
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