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Diffstat (limited to '')
| -rw-r--r-- | print-chdlc.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/print-chdlc.c b/print-chdlc.c new file mode 100644 index 0000000..235675d --- /dev/null +++ b/print-chdlc.c @@ -0,0 +1,198 @@ +/* + * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996, 1997 + * The Regents of the University of California. All rights reserved. + * + * 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, (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, and (3) all advertising materials mentioning + * features or use of this software display the following acknowledgement: + * ``This product includes software developed by the University of California, + * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of + * the University nor the names of its contributors may 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 + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. + */ + +/* \summary: Cisco HDLC printer */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include "netdissect-stdinc.h" + +#include "netdissect.h" +#include "addrtoname.h" +#include "ethertype.h" +#include "extract.h" +#include "chdlc.h" +#include "nlpid.h" + +static void chdlc_slarp_print(netdissect_options *, const u_char *, u_int); + +static const struct tok chdlc_cast_values[] = { + { CHDLC_UNICAST, "unicast" }, + { CHDLC_BCAST, "bcast" }, + { 0, NULL} +}; + + +/* Standard CHDLC printer */ +void +chdlc_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p) +{ + ndo->ndo_protocol = "chdlc"; + ndo->ndo_ll_hdr_len += chdlc_print(ndo, p, h->len); +} + +u_int +chdlc_print(netdissect_options *ndo, const u_char *p, u_int length) +{ + u_int proto; + const u_char *bp = p; + + ndo->ndo_protocol = "chdlc"; + if (length < CHDLC_HDRLEN) + goto trunc; + proto = GET_BE_U_2(p + 2); + if (ndo->ndo_eflag) { + ND_PRINT("%s, ethertype %s (0x%04x), length %u: ", + tok2str(chdlc_cast_values, "0x%02x", GET_U_1(p)), + tok2str(ethertype_values, "Unknown", proto), + proto, + length); + } + + length -= CHDLC_HDRLEN; + p += CHDLC_HDRLEN; + + switch (proto) { + case ETHERTYPE_IP: + ip_print(ndo, p, length); + break; + case ETHERTYPE_IPV6: + ip6_print(ndo, p, length); + break; + case CHDLC_TYPE_SLARP: + chdlc_slarp_print(ndo, p, length); + break; + case ETHERTYPE_MPLS: + case ETHERTYPE_MPLS_MULTI: + mpls_print(ndo, p, length); + break; + case ETHERTYPE_ISO: + /* is the fudge byte set ? lets verify by spotting ISO headers */ + if (length < 2) + goto trunc; + if (GET_U_1(p + 1) == NLPID_CLNP || + GET_U_1(p + 1) == NLPID_ESIS || + GET_U_1(p + 1) == NLPID_ISIS) + isoclns_print(ndo, p + 1, length - 1); + else + isoclns_print(ndo, p, length); + break; + default: + if (!ndo->ndo_eflag) + ND_PRINT("unknown CHDLC protocol (0x%04x)", proto); + break; + } + + return (CHDLC_HDRLEN); + +trunc: + nd_print_trunc(ndo); + return (ND_BYTES_AVAILABLE_AFTER(bp)); +} + +/* + * The fixed-length portion of a SLARP packet. + */ +struct cisco_slarp { + nd_uint32_t code; +#define SLARP_REQUEST 0 +#define SLARP_REPLY 1 +#define SLARP_KEEPALIVE 2 + union { + struct { + uint8_t addr[4]; + uint8_t mask[4]; + } addr; + struct { + nd_uint32_t myseq; + nd_uint32_t yourseq; + nd_uint16_t rel; + } keep; + } un; +}; + +#define SLARP_MIN_LEN 14 +#define SLARP_MAX_LEN 18 + +static void +chdlc_slarp_print(netdissect_options *ndo, const u_char *cp, u_int length) +{ + const struct cisco_slarp *slarp; + u_int sec,min,hrs,days; + + ndo->ndo_protocol = "chdlc_slarp"; + ND_PRINT("SLARP (length: %u), ",length); + if (length < SLARP_MIN_LEN) + goto trunc; + + slarp = (const struct cisco_slarp *)cp; + ND_TCHECK_LEN(slarp, SLARP_MIN_LEN); + switch (GET_BE_U_4(slarp->code)) { + case SLARP_REQUEST: + ND_PRINT("request"); + /* + * At least according to William "Chops" Westfield's + * message in + * + * https://web.archive.org/web/20190725151313/www.nethelp.no/net/cisco-hdlc.txt + * + * the address and mask aren't used in requests - + * they're just zero. + */ + break; + case SLARP_REPLY: + ND_PRINT("reply %s/%s", + GET_IPADDR_STRING(slarp->un.addr.addr), + GET_IPADDR_STRING(slarp->un.addr.mask)); + break; + case SLARP_KEEPALIVE: + ND_PRINT("keepalive: mineseen=0x%08x, yourseen=0x%08x, reliability=0x%04x", + GET_BE_U_4(slarp->un.keep.myseq), + GET_BE_U_4(slarp->un.keep.yourseq), + GET_BE_U_2(slarp->un.keep.rel)); + + if (length >= SLARP_MAX_LEN) { /* uptime-stamp is optional */ + cp += SLARP_MIN_LEN; + sec = GET_BE_U_4(cp) / 1000; + min = sec / 60; sec -= min * 60; + hrs = min / 60; min -= hrs * 60; + days = hrs / 24; hrs -= days * 24; + ND_PRINT(", link uptime=%ud%uh%um%us",days,hrs,min,sec); + } + break; + default: + ND_PRINT("0x%02x unknown", GET_BE_U_4(slarp->code)); + if (ndo->ndo_vflag <= 1) + print_unknown_data(ndo,cp+4,"\n\t",length-4); + break; + } + + if (SLARP_MAX_LEN < length && ndo->ndo_vflag) + ND_PRINT(", (trailing junk: %u bytes)", length - SLARP_MAX_LEN); + if (ndo->ndo_vflag > 1) + print_unknown_data(ndo,cp+4,"\n\t",length-4); + return; + +trunc: + nd_print_trunc(ndo); +} |