1 /* 2 * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996, 1997 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that: (1) source code distributions 7 * retain the above copyright notice and this paragraph in its entirety, (2) 8 * distributions including binary code include the above copyright notice and 9 * this paragraph in its entirety in the documentation or other materials 10 * provided with the distribution, and (3) all advertising materials mentioning 11 * features or use of this software display the following acknowledgement: 12 * ``This product includes software developed by the University of California, 13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 14 * the University nor the names of its contributors may be used to endorse 15 * or promote products derived from this software without specific prior 16 * written permission. 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 20 */ 21 22 /* \summary: Cisco HDLC printer */ 23 24 #include <config.h> 25 26 #include "netdissect-stdinc.h" 27 28 #include "netdissect.h" 29 #include "addrtoname.h" 30 #include "ethertype.h" 31 #include "extract.h" 32 #include "chdlc.h" 33 #include "nlpid.h" 34 35 static void chdlc_slarp_print(netdissect_options *, const u_char *, u_int); 36 37 static const struct tok chdlc_cast_values[] = { 38 { CHDLC_UNICAST, "unicast" }, 39 { CHDLC_BCAST, "bcast" }, 40 { 0, NULL} 41 }; 42 43 44 /* Standard CHDLC printer */ 45 void 46 chdlc_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p) 47 { 48 ndo->ndo_protocol = "chdlc"; 49 ndo->ndo_ll_hdr_len += chdlc_print(ndo, p, h->len); 50 } 51 52 u_int 53 chdlc_print(netdissect_options *ndo, const u_char *p, u_int length) 54 { 55 u_int proto; 56 const u_char *bp = p; 57 58 ndo->ndo_protocol = "chdlc"; 59 if (length < CHDLC_HDRLEN) 60 goto trunc; 61 proto = GET_BE_U_2(p + 2); 62 if (ndo->ndo_eflag) { 63 ND_PRINT("%s, ethertype %s (0x%04x), length %u: ", 64 tok2str(chdlc_cast_values, "0x%02x", GET_U_1(p)), 65 tok2str(ethertype_values, "Unknown", proto), 66 proto, 67 length); 68 } 69 70 length -= CHDLC_HDRLEN; 71 p += CHDLC_HDRLEN; 72 73 switch (proto) { 74 case ETHERTYPE_IP: 75 ip_print(ndo, p, length); 76 break; 77 case ETHERTYPE_IPV6: 78 ip6_print(ndo, p, length); 79 break; 80 case CHDLC_TYPE_SLARP: 81 chdlc_slarp_print(ndo, p, length); 82 break; 83 case ETHERTYPE_MPLS: 84 case ETHERTYPE_MPLS_MULTI: 85 mpls_print(ndo, p, length); 86 break; 87 case ETHERTYPE_ISO: 88 /* is the fudge byte set ? lets verify by spotting ISO headers */ 89 if (length < 2) 90 goto trunc; 91 if (GET_U_1(p + 1) == NLPID_CLNP || 92 GET_U_1(p + 1) == NLPID_ESIS || 93 GET_U_1(p + 1) == NLPID_ISIS) 94 isoclns_print(ndo, p + 1, length - 1); 95 else 96 isoclns_print(ndo, p, length); 97 break; 98 default: 99 if (!ndo->ndo_eflag) 100 ND_PRINT("unknown CHDLC protocol (0x%04x)", proto); 101 break; 102 } 103 104 return (CHDLC_HDRLEN); 105 106 trunc: 107 nd_print_trunc(ndo); 108 return (ND_BYTES_AVAILABLE_AFTER(bp)); 109 } 110 111 /* 112 * The fixed-length portion of a SLARP packet. 113 */ 114 struct cisco_slarp { 115 nd_uint32_t code; 116 #define SLARP_REQUEST 0 117 #define SLARP_REPLY 1 118 #define SLARP_KEEPALIVE 2 119 union { 120 struct { 121 uint8_t addr[4]; 122 uint8_t mask[4]; 123 } addr; 124 struct { 125 nd_uint32_t myseq; 126 nd_uint32_t yourseq; 127 nd_uint16_t rel; 128 } keep; 129 } un; 130 }; 131 132 #define SLARP_MIN_LEN 14 133 #define SLARP_MAX_LEN 18 134 135 static void 136 chdlc_slarp_print(netdissect_options *ndo, const u_char *cp, u_int length) 137 { 138 const struct cisco_slarp *slarp; 139 u_int sec,min,hrs,days; 140 141 ndo->ndo_protocol = "chdlc_slarp"; 142 ND_PRINT("SLARP (length: %u), ",length); 143 if (length < SLARP_MIN_LEN) 144 goto trunc; 145 146 slarp = (const struct cisco_slarp *)cp; 147 ND_TCHECK_LEN(slarp, SLARP_MIN_LEN); 148 switch (GET_BE_U_4(slarp->code)) { 149 case SLARP_REQUEST: 150 ND_PRINT("request"); 151 /* 152 * At least according to William "Chops" Westfield's 153 * message in 154 * 155 * https://web.archive.org/web/20190725151313/www.nethelp.no/net/cisco-hdlc.txt 156 * 157 * the address and mask aren't used in requests - 158 * they're just zero. 159 */ 160 break; 161 case SLARP_REPLY: 162 ND_PRINT("reply %s/%s", 163 GET_IPADDR_STRING(slarp->un.addr.addr), 164 GET_IPADDR_STRING(slarp->un.addr.mask)); 165 break; 166 case SLARP_KEEPALIVE: 167 ND_PRINT("keepalive: mineseen=0x%08x, yourseen=0x%08x, reliability=0x%04x", 168 GET_BE_U_4(slarp->un.keep.myseq), 169 GET_BE_U_4(slarp->un.keep.yourseq), 170 GET_BE_U_2(slarp->un.keep.rel)); 171 172 if (length >= SLARP_MAX_LEN) { /* uptime-stamp is optional */ 173 cp += SLARP_MIN_LEN; 174 sec = GET_BE_U_4(cp) / 1000; 175 min = sec / 60; sec -= min * 60; 176 hrs = min / 60; min -= hrs * 60; 177 days = hrs / 24; hrs -= days * 24; 178 ND_PRINT(", link uptime=%ud%uh%um%us",days,hrs,min,sec); 179 } 180 break; 181 default: 182 ND_PRINT("0x%02x unknown", GET_BE_U_4(slarp->code)); 183 if (ndo->ndo_vflag <= 1) 184 print_unknown_data(ndo,cp+4,"\n\t",length-4); 185 break; 186 } 187 188 if (SLARP_MAX_LEN < length && ndo->ndo_vflag) 189 ND_PRINT(", (trailing junk: %u bytes)", length - SLARP_MAX_LEN); 190 if (ndo->ndo_vflag > 1) 191 print_unknown_data(ndo,cp+4,"\n\t",length-4); 192 return; 193 194 trunc: 195 nd_print_trunc(ndo); 196 } 197