X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/a11713da52b0a72a1cb17f00fc339d332866e9ca..refs/heads/tcpdump-4.1:/print-gre.c diff --git a/print-gre.c b/print-gre.c index 4accdfe0..106e6fd3 100644 --- a/print-gre.c +++ b/print-gre.c @@ -1,176 +1,403 @@ +/* $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. + * 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 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. + */ + +/* + * tcpdump filter for GRE - Generic Routing Encapsulation + * RFC1701 (GRE), RFC1702 (GRE IPv4), and RFC2637 (Enhanced GRE) */ #ifndef lint -static const char rcsid[] = - "@(#) $Header: /tcpdump/master/tcpdump/print-gre.c,v 1.13 2001-06-15 22:17:31 fenner Exp $"; +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 -#include -#include -#include - -#include +#include -#include #include +#include #include "interface.h" #include "addrtoname.h" -#include "extract.h" /* must come after interface.h */ +#include "extract.h" + +#include "ip.h" +#include "ethertype.h" -struct gre { - u_int16_t flags; - u_int16_t proto; +#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 } }; -/* RFC 2784 - GRE */ -#define GRE_CP 0x8000 /* Checksum Present */ -#define GRE_VER_MASK 0x0007 /* Version */ +#define GRE_VERS_MASK 0x0007 /* protocol version */ -/* RFC 2890 - Key and Sequence extensions to GRE */ -#define GRE_KP 0x2000 /* Key Present */ -#define GRE_SP 0x1000 /* Sequence Present */ +/* source route entry types */ +#define GRESRE_IP 0x0800 /* IP */ +#define GRESRE_ASN 0xfffe /* ASN */ -/* Legacy from RFC 1700 */ -#define GRE_RP 0x4000 /* Routing Present */ -#define GRE_sP 0x0800 /* strict source route present */ -#define GRE_RECUR_MASK 0x0700 /* Recursion Control */ -#define GRE_RECUR_SHIFT 8 +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); -#define GRE_COP (GRE_RP|GRE_CP) /* Checksum & Offset Present */ +void +gre_print(const u_char *bp, u_int length) +{ + u_int len = length, vers; -/* "Enhanced GRE" from RFC2637 - PPTP */ -#define GRE_AP 0x0080 /* Ack present */ + if (len < 2) { + printf("[|gre]"); + return; + } + vers = EXTRACT_16BITS(bp) & GRE_VERS_MASK; + printf("GREv%u",vers); -#define GRE_MBZ_MASK 0x0078 /* not defined */ + 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; + +} -/* - * Deencapsulate and print a GRE-tunneled IP datagram - */ void -gre_print(const u_char *bp, u_int length) +gre_print_0(const u_char *bp, u_int length) { - const u_char *cp = bp + 4; - const struct gre *gre; - u_int16_t flags, proto; - u_short ver=0; - u_short extracted_ethertype; - - gre = (const struct gre *)bp; - - TCHECK(gre->proto); - flags = EXTRACT_16BITS(&gre->flags); - proto = EXTRACT_16BITS(&gre->proto); - (void)printf("gre "); - - if (flags) { - /* 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'); - if (flags & GRE_sP) - putchar('s'); - if (flags & GRE_AP) - putchar('A'); - if (flags & GRE_RECUR_MASK) - printf("R%x", (flags & GRE_RECUR_MASK) >> GRE_RECUR_SHIFT); - ver = flags & GRE_VER_MASK; - printf("v%u", ver); - - if (flags & GRE_MBZ_MASK) - printf("!%x", flags & GRE_MBZ_MASK); - fputs("] ", stdout); - } - - if (flags & GRE_COP) { - int checksum, offset; - - TCHECK2(*cp, 4); - checksum = EXTRACT_16BITS(cp); - offset = EXTRACT_16BITS(cp + 2); - - if (flags & GRE_CP) { - /* Checksum present */ - - /* todo: check checksum */ - if (vflag > 1) - printf("C:%04x ", checksum); - } - if (flags & GRE_RP) { - /* Offset present */ + u_int len = length; + u_int16_t flags, prot; - if (vflag > 1) - printf("O:%04x ", offset); - } - cp += 4; /* skip checksum and offset */ + 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) { - TCHECK2(*cp, 4); - if (ver == 1) { /* PPTP */ - if (vflag > 1) - printf("PL:%u ", EXTRACT_16BITS(cp)); - printf("ID:%04x ", EXTRACT_16BITS(cp+2)); + 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; } - else - printf("K:%08x ", EXTRACT_32BITS(cp)); - cp += 4; /* skip key */ } + + 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; + case ETHERTYPE_TEB: + ether_print(bp, len, len, NULL, NULL); + 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) { - TCHECK2(*cp, 4); - printf("S:%u ", EXTRACT_32BITS(cp)); - cp += 4; /* skip seq */ + if (len < 4) + goto trunc; + printf(", seq %u", EXTRACT_32BITS(bp)); + bp += 4; + len -= 4; } - if (flags & GRE_AP && ver >= 1) { - TCHECK2(*cp, 4); - printf("A:%u ", EXTRACT_32BITS(cp)); - cp += 4; /* skip ack */ + + if (flags & GRE_AP) { + if (len < 4) + goto trunc; + printf(", ack %u", EXTRACT_32BITS(bp)); + bp += 4; + len -= 4; } - /* We don't support routing fields (variable length) now. Punt. */ - if (flags & GRE_RP) - return; - TCHECK(cp[0]); + 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); - length -= cp - bp; - if (ether_encap_print(proto, cp, length, length, - &extracted_ethertype) == 0) - printf("gre-proto-0x%04X", proto); + 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: - fputs("[|gre]", stdout); + 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; + } }