X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/7c4458eb6a0cd2a617adb9a3bbca44e9f59f3937..c39d40a767a1ae36171e5bcbf6f157ff3e80fb6c:/print-gre.c diff --git a/print-gre.c b/print-gre.c index 1e801b91..b1a81429 100644 --- a/print-gre.c +++ b/print-gre.c @@ -1,134 +1,414 @@ +/* $OpenBSD: print-gre.c,v 1.6 2002/10/30 03:04:04 fgsch Exp $ */ + /* - * Copyright (c) 1996 - * The Regents of the University of California. All rights reserved. - * - * Redistribution and use in source and binary forms are permitted - * provided that the above copyright notice and this paragraph are - * duplicated in all such forms and that any documentation, - * advertising materials, and other materials related to such - * distribution and use acknowledge that the software was developed - * by the University of California, Lawrence Berkeley Laboratory, - * Berkeley, CA. The name of the University may not be used to - * endorse or promote products derived from this software without - * specific prior written permission. - * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR - * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED - * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. + * Copyright (c) 2002 Jason L. Wright (jason@thought.net) + * All rights reserved. * - * Initial contribution from John Hawkinson + * 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 module implements support for decoding GRE (Generic Routing - * Encapsulation) tunnels; they're documented in RFC1701 and RFC1702. - * This code only supports the IP encapsulation thereof. + * 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. */ -#ifndef lint -static const char rcsid[] = - "@(#) $Header: /tcpdump/master/tcpdump/print-gre.c,v 1.9 2000-12-18 05:41:59 guy Exp $"; -#endif +/* \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" +#include #endif -#include -#include -#include -#include - -#include - -#include -#include - -#include "interface.h" -#include "addrtoname.h" -#include "extract.h" /* must come after interface.h */ - -#define GRE_SIZE (20) - -struct gre { - u_short flags; - u_short proto; - union { - struct gre_ckof { - u_short cksum; - u_short offset; - } gre_ckof; - u_int32_t key; - u_int32_t seq; - } gre_void1; - union { - u_int32_t key; - u_int32_t seq; - u_int32_t routing; - } gre_void2; - union { - u_int32_t seq; - u_int32_t routing; - } gre_void3; - union { - u_int32_t routing; - } gre_void4; +#include "netdissect-stdinc.h" + +#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_CP 0x8000 /* Checksum Present */ -#define GRE_RP 0x4000 /* Routing Present */ -#define GRE_KP 0x2000 /* Key Present */ -#define GRE_SP 0x1000 /* Sequence Present */ +#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); -/* - * Deencapsulate and print a GRE-tunneled IP datagram - */ void -gre_print(const u_char *bp, u_int length) +gre_print(netdissect_options *ndo, const u_char *bp, u_int length) +{ + u_int len = length, vers; + + ndo->ndo_protocol = "gre"; + ND_TCHECK_2(bp); + if (len < 2) + goto trunc; + vers = GET_BE_U_2(bp) & GRE_VERS_MASK; + ND_PRINT("GREv%u",vers); + + switch(vers) { + case 0: + gre_print_0(ndo, bp, len); + break; + case 1: + gre_print_1(ndo, bp, len); + break; + default: + ND_PRINT(" ERROR: unknown-version"); + break; + } + return; + +trunc: + nd_print_trunc(ndo); +} + +static void +gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length) +{ + u_int len = length; + uint16_t flags, prot; + + /* 16 bits ND_TCHECKed in gre_print() */ + 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_TCHECK_2(bp); + if (len < 2) + goto trunc; + prot = GET_BE_U_2(bp); + len -= 2; + bp += 2; + + if ((flags & GRE_CP) | (flags & GRE_RP)) { + ND_TCHECK_2(bp); + if (len < 2) + goto trunc; + if (ndo->ndo_vflag) + ND_PRINT(", sum 0x%x", GET_BE_U_2(bp)); + bp += 2; + len -= 2; + + ND_TCHECK_2(bp); + if (len < 2) + goto trunc; + ND_PRINT(", off 0x%x", GET_BE_U_2(bp)); + bp += 2; + len -= 2; + } + + if (flags & GRE_KP) { + ND_TCHECK_4(bp); + if (len < 4) + goto trunc; + ND_PRINT(", key=0x%x", GET_BE_U_4(bp)); + bp += 4; + len -= 4; + } + + if (flags & GRE_SP) { + ND_TCHECK_4(bp); + if (len < 4) + goto trunc; + 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_TCHECK_4(bp); + if (len < 4) + goto trunc; + 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 trunc; + + if (len < srelen) + goto trunc; + 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; + +trunc: + nd_print_trunc(ndo); +} + +static void +gre_print_1(netdissect_options *ndo, const u_char *bp, u_int length) { - const u_char *cp = bp + 4; - const struct gre *gre; - u_short flags, proto, extracted_ethertype; + u_int len = length; + uint16_t flags, prot; + + /* 16 bits ND_TCHECKed in gre_print() */ + flags = GET_BE_U_2(bp); + len -= 2; + bp += 2; - gre = (const struct gre *)bp; + if (ndo->ndo_vflag) + ND_PRINT(", Flags [%s]", + bittok2str(gre_flag_values,"none",flags)); - if (length < GRE_SIZE) { + ND_TCHECK_2(bp); + if (len < 2) goto trunc; + prot = GET_BE_U_2(bp); + len -= 2; + bp += 2; + + + if (flags & GRE_KP) { + uint32_t k; + + ND_TCHECK_4(bp); + if (len < 4) + goto trunc; + k = GET_BE_U_4(bp); + ND_PRINT(", call %u", k & 0xffff); + len -= 4; + bp += 4; } - flags = EXTRACT_16BITS(&gre->flags); - proto = EXTRACT_16BITS(&gre->proto); - - if (vflag) { - /* Decode the flags */ - putchar('['); - if (flags & GRE_CP) - putchar('C'); - if (flags & GRE_RP) - putchar('R'); - if (flags & GRE_KP) - putchar('K'); - if (flags & GRE_SP) - putchar('S'); - fputs("] ", stdout); - } - /* Checksum & Offset are present */ - if ((flags & GRE_CP) | (flags & GRE_RP)) - cp += 4; - - /* We don't support routing fields (variable length) now. Punt. */ - if (flags & GRE_RP) + + if (flags & GRE_SP) { + ND_TCHECK_4(bp); + if (len < 4) + goto trunc; + ND_PRINT(", seq %u", GET_BE_U_4(bp)); + bp += 4; + len -= 4; + } + + if (flags & GRE_AP) { + ND_TCHECK_4(bp); + if (len < 4) + goto trunc; + 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 (flags & GRE_KP) - cp += 4; - if (flags & GRE_SP) - cp += 4; + if (ndo->ndo_vflag < 1) + ND_PRINT(": "); /* put in a colon as protocol demarc */ + else + ND_PRINT("\n\t"); /* if verbose go multiline */ - length -= cp - bp; - if (ether_encap_print(proto, cp, length, length, - &extracted_ethertype) == 0) - printf("gre-proto-0x%04X", proto); + switch (prot) { + case ETHERTYPE_PPP: + ppp_print(ndo, bp, len); + break; + default: + ND_PRINT("gre-proto-0x%x", prot); + break; + } return; trunc: - fputs("[|gre]", stdout); + nd_print_trunc(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); + return (1); + } + if (srelen & 3) { + ND_PRINT(", badlength=%u", srelen); + return (1); + } + if (sreoff >= srelen) { + ND_PRINT(", badoff/len=%u/%u", sreoff, srelen); + return (1); + } + + while (srelen != 0) { + ND_TCHECK_4(bp); + if (len < 4) + return (0); + + addrtostr(bp, buf, sizeof(buf)); + ND_PRINT(" %s%s", + ((bp - up) == sreoff) ? "*" : "", buf); + + bp += 4; + len -= 4; + srelen -= 4; + } + return (1); +trunc: + 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); + return (1); + } + if (srelen & 1) { + ND_PRINT(", badlength=%u", srelen); + return (1); + } + if (sreoff >= srelen) { + ND_PRINT(", badoff/len=%u/%u", sreoff, srelen); + return (1); + } + + while (srelen != 0) { + ND_TCHECK_2(bp); + if (len < 2) + return (0); + + ND_PRINT(" %s%x", + ((bp - up) == sreoff) ? "*" : "", GET_BE_U_2(bp)); + + bp += 2; + len -= 2; + srelen -= 2; + } + return (1); +trunc: + return 0; }