diff options
Diffstat (limited to 'contrib/tcpdump/print-gre.c')
| -rw-r--r-- | contrib/tcpdump/print-gre.c | 400 |
1 files changed, 400 insertions, 0 deletions
diff --git a/contrib/tcpdump/print-gre.c b/contrib/tcpdump/print-gre.c new file mode 100644 index 0000000..55f0e9d --- /dev/null +++ b/contrib/tcpdump/print-gre.c @@ -0,0 +1,400 @@ +/* $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. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by Jason L. Wright + * 4. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * 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. + */ + +/* + * tcpdump filter for GRE - Generic Routing Encapsulation + * RFC1701 (GRE), RFC1702 (GRE IPv4), and RFC2637 (Enhanced GRE) + */ + +#ifndef lint +static const char rcsid[] _U_ = + "@(#) $Header: /tcpdump/master/tcpdump/print-gre.c,v 1.28 2005-04-06 21:32:39 mcr Exp $ (LBL)"; +#endif + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <tcpdump-stdinc.h> + +#include <stdio.h> +#include <string.h> + +#include "interface.h" +#include "addrtoname.h" +#include "extract.h" + +#include "ip.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_RECRS 0x0700 /* recursion count */ +#define GRE_AP 0x0080 /* acknowledgment# present */ + +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_RECRS, "recursion count"}, + { GRE_AP, "ack present"}, + { 0, NULL } +}; + +#define GRE_VERS_MASK 0x0007 /* protocol version */ + +/* source route entry types */ +#define GRESRE_IP 0x0800 /* IP */ +#define GRESRE_ASN 0xfffe /* ASN */ + +void gre_print_0(const u_char *, u_int); +void gre_print_1(const u_char *, u_int); +void gre_sre_print(u_int16_t, u_int8_t, u_int8_t, const u_char *, u_int); +void gre_sre_ip_print(u_int8_t, u_int8_t, const u_char *, u_int); +void gre_sre_asn_print(u_int8_t, u_int8_t, const u_char *, u_int); + +void +gre_print(const u_char *bp, u_int length) +{ + u_int len = length, vers; + + if (len < 2) { + printf("[|gre]"); + return; + } + vers = EXTRACT_16BITS(bp) & GRE_VERS_MASK; + printf("GREv%u",vers); + + switch(vers) { + case 0: + gre_print_0(bp, len); + break; + case 1: + gre_print_1(bp, len); + break; + default: + printf(" ERROR: unknown-version"); + break; + } + return; + +} + +void +gre_print_0(const u_char *bp, u_int length) +{ + u_int len = length; + u_int16_t flags, prot; + + flags = EXTRACT_16BITS(bp); + if (vflag) + printf(", Flags [%s]", + bittok2str(gre_flag_values,"none",flags)); + + len -= 2; + bp += 2; + + if (len < 2) + goto trunc; + prot = EXTRACT_16BITS(bp); + len -= 2; + bp += 2; + + if ((flags & GRE_CP) | (flags & GRE_RP)) { + if (len < 2) + goto trunc; + if (vflag) + printf(", sum 0x%x", EXTRACT_16BITS(bp)); + bp += 2; + len -= 2; + + if (len < 2) + goto trunc; + printf(", off 0x%x", EXTRACT_16BITS(bp)); + bp += 2; + len -= 2; + } + + if (flags & GRE_KP) { + if (len < 4) + goto trunc; + printf(", key=0x%x", EXTRACT_32BITS(bp)); + bp += 4; + len -= 4; + } + + if (flags & GRE_SP) { + if (len < 4) + goto trunc; + printf(", seq %u", EXTRACT_32BITS(bp)); + bp += 4; + len -= 4; + } + + if (flags & GRE_RP) { + for (;;) { + u_int16_t af; + u_int8_t sreoff; + u_int8_t srelen; + + if (len < 4) + goto trunc; + af = EXTRACT_16BITS(bp); + sreoff = *(bp + 2); + srelen = *(bp + 3); + bp += 4; + len -= 4; + + if (af == 0 && srelen == 0) + break; + + gre_sre_print(af, sreoff, srelen, bp, len); + + if (len < srelen) + goto trunc; + bp += srelen; + len -= srelen; + } + } + + if (eflag) + printf(", proto %s (0x%04x)", + tok2str(ethertype_values,"unknown",prot), + prot); + + printf(", length %u",length); + + if (vflag < 1) + printf(": "); /* put in a colon as protocol demarc */ + else + printf("\n\t"); /* if verbose go multiline */ + + switch (prot) { + case ETHERTYPE_IP: + ip_print(gndo, bp, len); + break; +#ifdef INET6 + case ETHERTYPE_IPV6: + ip6_print(bp, len); + break; +#endif + case ETHERTYPE_MPLS: + mpls_print(bp, len); + break; + case ETHERTYPE_IPX: + ipx_print(bp, len); + break; + case ETHERTYPE_ATALK: + atalk_print(bp, len); + break; + case ETHERTYPE_GRE_ISO: + isoclns_print(bp, len, len); + break; + default: + printf("gre-proto-0x%x", prot); + } + return; + +trunc: + printf("[|gre]"); +} + +void +gre_print_1(const u_char *bp, u_int length) +{ + u_int len = length; + u_int16_t flags, prot; + + flags = EXTRACT_16BITS(bp); + len -= 2; + bp += 2; + + if (vflag) + printf(", Flags [%s]", + bittok2str(gre_flag_values,"none",flags)); + + if (len < 2) + goto trunc; + prot = EXTRACT_16BITS(bp); + len -= 2; + bp += 2; + + + if (flags & GRE_KP) { + u_int32_t k; + + if (len < 4) + goto trunc; + k = EXTRACT_32BITS(bp); + printf(", call %d", k & 0xffff); + len -= 4; + bp += 4; + } + + if (flags & GRE_SP) { + if (len < 4) + goto trunc; + printf(", seq %u", EXTRACT_32BITS(bp)); + bp += 4; + len -= 4; + } + + if (flags & GRE_AP) { + if (len < 4) + goto trunc; + printf(", ack %u", EXTRACT_32BITS(bp)); + bp += 4; + len -= 4; + } + + if ((flags & GRE_SP) == 0) + printf(", no-payload"); + + if (eflag) + printf(", proto %s (0x%04x)", + tok2str(ethertype_values,"unknown",prot), + prot); + + printf(", length %u",length); + + if ((flags & GRE_SP) == 0) + return; + + if (vflag < 1) + printf(": "); /* put in a colon as protocol demarc */ + else + printf("\n\t"); /* if verbose go multiline */ + + switch (prot) { + case ETHERTYPE_PPP: + ppp_print(bp, len); + break; + default: + printf("gre-proto-0x%x", prot); + break; + } + return; + +trunc: + printf("[|gre]"); +} + +void +gre_sre_print(u_int16_t af, u_int8_t sreoff, u_int8_t srelen, + const u_char *bp, u_int len) +{ + switch (af) { + case GRESRE_IP: + printf(", (rtaf=ip"); + gre_sre_ip_print(sreoff, srelen, bp, len); + printf(") "); + break; + case GRESRE_ASN: + printf(", (rtaf=asn"); + gre_sre_asn_print(sreoff, srelen, bp, len); + printf(") "); + break; + default: + printf(", (rtaf=0x%x) ", af); + } +} +void +gre_sre_ip_print(u_int8_t sreoff, u_int8_t srelen, const u_char *bp, u_int len) +{ + struct in_addr a; + const u_char *up = bp; + + if (sreoff & 3) { + printf(", badoffset=%u", sreoff); + return; + } + if (srelen & 3) { + printf(", badlength=%u", srelen); + return; + } + if (sreoff >= srelen) { + printf(", badoff/len=%u/%u", sreoff, srelen); + return; + } + + for (;;) { + if (len < 4 || srelen == 0) + return; + + memcpy(&a, bp, sizeof(a)); + printf(" %s%s", + ((bp - up) == sreoff) ? "*" : "", + inet_ntoa(a)); + + bp += 4; + len -= 4; + srelen -= 4; + } +} + +void +gre_sre_asn_print(u_int8_t sreoff, u_int8_t srelen, const u_char *bp, u_int len) +{ + const u_char *up = bp; + + if (sreoff & 1) { + printf(", badoffset=%u", sreoff); + return; + } + if (srelen & 1) { + printf(", badlength=%u", srelen); + return; + } + if (sreoff >= srelen) { + printf(", badoff/len=%u/%u", sreoff, srelen); + return; + } + + for (;;) { + if (len < 2 || srelen == 0) + return; + + printf(" %s%x", + ((bp - up) == sreoff) ? "*" : "", + EXTRACT_16BITS(bp)); + + bp += 2; + len -= 2; + srelen -= 2; + } +} |
