1 /* Copyright (c) 2015, bugyo 2 * All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are met: 6 * 1. Redistributions of source code must retain the above copyright notice, 7 * this list of conditions and the following disclaimer. 8 * 2. Redistributions in binary form must reproduce the above copyright notice, 9 * this list of conditions and the following disclaimer in the documentation 10 * and/or other materials provided with the distribution. 11 * 12 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 13 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 14 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 15 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR 16 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 17 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 18 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 19 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 20 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 21 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 22 */ 23 24 #include <sys/cdefs.h> 25 #ifndef lint 26 __RCSID("$NetBSD: print-nsh.c,v 1.5 2024/09/02 16:15:32 christos Exp $"); 27 #endif 28 29 /* \summary: Network Service Header (NSH) printer */ 30 31 /* specification: RFC 8300 */ 32 33 #include <config.h> 34 35 #include "netdissect-stdinc.h" 36 37 #define ND_LONGJMP_FROM_TCHECK 38 #include "netdissect.h" 39 #include "extract.h" 40 41 static const struct tok nsh_flags [] = { 42 { 0x2, "O" }, 43 { 0, NULL } 44 }; 45 46 /* 47 * 0 1 2 3 48 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 49 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 50 * |Ver|O|U| TTL | Length |U|U|U|U|MD Type| Next Protocol | 51 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 52 */ 53 #define NSH_BASE_HDR_LEN 4 54 #define NSH_VER(x) (((x) & 0xc0000000) >> 30) 55 #define NSH_FLAGS(x) (((x) & 0x30000000) >> 28) 56 #define NSH_TTL(x) (((x) & 0x0fc00000) >> 22) 57 #define NSH_LENGTH(x) (((x) & 0x003f0000) >> 16) 58 #define NSH_MD_TYPE(x) (((x) & 0x00000f00) >> 8) 59 #define NSH_NEXT_PROT(x) (((x) & 0x000000ff) >> 0) 60 61 #define NSH_SERVICE_PATH_HDR_LEN 4 62 #define NSH_HDR_WORD_SIZE 4U 63 64 #define MD_RSV 0x00 65 #define MD_TYPE1 0x01 66 #define MD_TYPE2 0x02 67 #define MD_EXP 0x0F 68 static const struct tok md_str[] = { 69 { MD_RSV, "reserved" }, 70 { MD_TYPE1, "1" }, 71 { MD_TYPE2, "2" }, 72 { MD_EXP, "experimental" }, 73 { 0, NULL } 74 }; 75 76 #define NP_IPV4 0x01 77 #define NP_IPV6 0x02 78 #define NP_ETH 0x03 79 #define NP_NSH 0x04 80 #define NP_MPLS 0x05 81 #define NP_EXP1 0xFE 82 #define NP_EXP2 0xFF 83 static const struct tok np_str[] = { 84 { NP_IPV4, "IPv4" }, 85 { NP_IPV6, "IPv6" }, 86 { NP_ETH, "Ethernet" }, 87 { NP_NSH, "NSH" }, 88 { NP_MPLS, "MPLS" }, 89 { NP_EXP1, "Experiment 1" }, 90 { NP_EXP2, "Experiment 2" }, 91 { 0, NULL } 92 }; 93 94 void 95 nsh_print(netdissect_options *ndo, const u_char *bp, u_int len) 96 { 97 uint32_t basehdr; 98 u_int ver, length, md_type; 99 uint8_t next_protocol; 100 u_char past_headers = 0; 101 u_int next_len; 102 103 ndo->ndo_protocol = "nsh"; 104 /* 105 * 0 1 2 3 106 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 107 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 108 * | Base Header | 109 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 110 * | Service Path Header | 111 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 112 * | | 113 * ~ Context Header(s) ~ 114 * | | 115 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 116 */ 117 118 /* print Base Header and Service Path Header */ 119 if (len < NSH_BASE_HDR_LEN + NSH_SERVICE_PATH_HDR_LEN) { 120 ND_PRINT(" (packet length %u < %u)", 121 len, NSH_BASE_HDR_LEN + NSH_SERVICE_PATH_HDR_LEN); 122 goto invalid; 123 } 124 125 basehdr = GET_BE_U_4(bp); 126 bp += 4; 127 ver = NSH_VER(basehdr); 128 length = NSH_LENGTH(basehdr); 129 md_type = NSH_MD_TYPE(basehdr); 130 next_protocol = NSH_NEXT_PROT(basehdr); 131 132 ND_PRINT("NSH, "); 133 if (ndo->ndo_vflag > 1) { 134 ND_PRINT("ver %u, ", ver); 135 } 136 if (ver != 0) 137 return; 138 ND_PRINT("flags [%s], ", 139 bittok2str_nosep(nsh_flags, "none", NSH_FLAGS(basehdr))); 140 if (ndo->ndo_vflag > 2) { 141 ND_PRINT("TTL %u, ", NSH_TTL(basehdr)); 142 ND_PRINT("length %u, ", length); 143 ND_PRINT("md type %s, ", tok2str(md_str, "unknown (0x%02x)", md_type)); 144 } 145 if (ndo->ndo_vflag > 1) { 146 ND_PRINT("next-protocol %s, ", 147 tok2str(np_str, "unknown (0x%02x)", next_protocol)); 148 } 149 150 /* Make sure we have all the headers */ 151 if (len < length * NSH_HDR_WORD_SIZE) { 152 ND_PRINT(" (too many headers for packet length %u)", len); 153 goto invalid; 154 } 155 156 /* 157 * 0 1 2 3 158 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 159 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 160 * | Service Path Identifier (SPI) | Service Index | 161 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 162 * 163 */ 164 ND_PRINT("service-path-id 0x%06x, ", GET_BE_U_3(bp)); 165 bp += 3; 166 ND_PRINT("service-index 0x%x", GET_U_1(bp)); 167 bp += 1; 168 169 /* 170 * length includes the lengths of the Base and Service Path headers. 171 * That means it must be at least 2. 172 */ 173 if (length < 2) { 174 ND_PRINT(" (less than two headers)"); 175 goto invalid; 176 } 177 178 /* 179 * Print, or skip, the Context Headers. 180 * (length - 2) is the length of those headers. 181 */ 182 if (ndo->ndo_vflag > 2) { 183 u_int n; 184 185 if (md_type == MD_TYPE1) { 186 if (length != 6) { 187 ND_PRINT(" (length for the MD type)"); 188 goto invalid; 189 } 190 for (n = 0; n < length - 2; n++) { 191 ND_PRINT("\n Context[%02u]: 0x%08x", n, GET_BE_U_4(bp)); 192 bp += NSH_HDR_WORD_SIZE; 193 } 194 past_headers = 1; 195 } else if (md_type == MD_TYPE2) { 196 n = 0; 197 while (n < length - 2) { 198 uint16_t tlv_class; 199 uint8_t tlv_type, tlv_len, tlv_len_padded; 200 201 tlv_class = GET_BE_U_2(bp); 202 bp += 2; 203 tlv_type = GET_U_1(bp); 204 bp += 1; 205 tlv_len = GET_U_1(bp) & 0x7f; 206 bp += 1; 207 tlv_len_padded = roundup2(tlv_len, NSH_HDR_WORD_SIZE); 208 209 ND_PRINT("\n TLV Class %u, Type %u, Len %u", 210 tlv_class, tlv_type, tlv_len); 211 212 n += 1; 213 214 if (length - 2 < n + tlv_len_padded / NSH_HDR_WORD_SIZE) { 215 ND_PRINT(" (length too big)"); 216 goto invalid; 217 } 218 219 if (tlv_len) { 220 const char *sep = "0x"; 221 u_int vn; 222 223 ND_PRINT("\n Value: "); 224 for (vn = 0; vn < tlv_len; vn++) { 225 ND_PRINT("%s%02x", sep, GET_U_1(bp)); 226 bp += 1; 227 sep = ":"; 228 } 229 /* Cover any TLV padding. */ 230 ND_TCHECK_LEN(bp, tlv_len_padded - tlv_len); 231 bp += tlv_len_padded - tlv_len; 232 n += tlv_len_padded / NSH_HDR_WORD_SIZE; 233 } 234 } 235 past_headers = 1; 236 } 237 } 238 if (! past_headers) { 239 ND_TCHECK_LEN(bp, (length - 2) * NSH_HDR_WORD_SIZE); 240 bp += (length - 2) * NSH_HDR_WORD_SIZE; 241 } 242 ND_PRINT(ndo->ndo_vflag ? "\n " : ": "); 243 244 /* print Next Protocol */ 245 next_len = len - length * NSH_HDR_WORD_SIZE; 246 switch (next_protocol) { 247 case NP_IPV4: 248 ip_print(ndo, bp, next_len); 249 break; 250 case NP_IPV6: 251 ip6_print(ndo, bp, next_len); 252 break; 253 case NP_ETH: 254 ether_print(ndo, bp, next_len, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL); 255 break; 256 default: 257 ND_PRINT("ERROR: unknown-next-protocol"); 258 return; 259 } 260 261 return; 262 263 invalid: 264 nd_print_invalid(ndo); 265 } 266 267