/* Copyright (c) 2015, bugyo * All rights reserved. * * 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 SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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. */ /* \summary: Network Service Header (NSH) printer */ /* specification: RFC 8300 */ #include #include "netdissect-stdinc.h" #define ND_LONGJMP_FROM_TCHECK #include "netdissect.h" #include "extract.h" static const struct tok nsh_flags [] = { { 0x2, "O" }, { 0, NULL } }; /* * 0 1 2 3 * 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 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * |Ver|O|U| TTL | Length |U|U|U|U|MD Type| Next Protocol | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */ #define NSH_BASE_HDR_LEN 4 #define NSH_VER(x) (((x) & 0xc0000000) >> 30) #define NSH_FLAGS(x) (((x) & 0x30000000) >> 28) #define NSH_TTL(x) (((x) & 0x0fc00000) >> 22) #define NSH_LENGTH(x) (((x) & 0x003f0000) >> 16) #define NSH_MD_TYPE(x) (((x) & 0x00000f00) >> 8) #define NSH_NEXT_PROT(x) (((x) & 0x000000ff) >> 0) #define NSH_SERVICE_PATH_HDR_LEN 4 #define NSH_HDR_WORD_SIZE 4U #define MD_RSV 0x00 #define MD_TYPE1 0x01 #define MD_TYPE2 0x02 #define MD_EXP 0x0F static const struct tok md_str[] = { { MD_RSV, "reserved" }, { MD_TYPE1, "1" }, { MD_TYPE2, "2" }, { MD_EXP, "experimental" }, { 0, NULL } }; #define NP_IPV4 0x01 #define NP_IPV6 0x02 #define NP_ETH 0x03 #define NP_NSH 0x04 #define NP_MPLS 0x05 #define NP_EXP1 0xFE #define NP_EXP2 0xFF static const struct tok np_str[] = { { NP_IPV4, "IPv4" }, { NP_IPV6, "IPv6" }, { NP_ETH, "Ethernet" }, { NP_NSH, "NSH" }, { NP_MPLS, "MPLS" }, { NP_EXP1, "Experiment 1" }, { NP_EXP2, "Experiment 2" }, { 0, NULL } }; void nsh_print(netdissect_options *ndo, const u_char *bp, u_int len) { uint32_t basehdr; u_int ver, length, md_type; uint8_t next_protocol; u_char past_headers = 0; u_int next_len; ndo->ndo_protocol = "nsh"; /* * 0 1 2 3 * 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 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Base Header | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Service Path Header | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | | * ~ Context Header(s) ~ * | | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */ /* print Base Header and Service Path Header */ if (len < NSH_BASE_HDR_LEN + NSH_SERVICE_PATH_HDR_LEN) { ND_PRINT(" (packet length %u < %u)", len, NSH_BASE_HDR_LEN + NSH_SERVICE_PATH_HDR_LEN); goto invalid; } basehdr = GET_BE_U_4(bp); bp += 4; ver = NSH_VER(basehdr); length = NSH_LENGTH(basehdr); md_type = NSH_MD_TYPE(basehdr); next_protocol = NSH_NEXT_PROT(basehdr); ND_PRINT("NSH, "); if (ndo->ndo_vflag > 1) { ND_PRINT("ver %u, ", ver); } if (ver != 0) return; ND_PRINT("flags [%s], ", bittok2str_nosep(nsh_flags, "none", NSH_FLAGS(basehdr))); if (ndo->ndo_vflag > 2) { ND_PRINT("TTL %u, ", NSH_TTL(basehdr)); ND_PRINT("length %u, ", length); ND_PRINT("md type %s, ", tok2str(md_str, "unknown (0x%02x)", md_type)); } if (ndo->ndo_vflag > 1) { ND_PRINT("next-protocol %s, ", tok2str(np_str, "unknown (0x%02x)", next_protocol)); } /* Make sure we have all the headers */ if (len < length * NSH_HDR_WORD_SIZE) { ND_PRINT(" (too many headers for packet length %u)", len); goto invalid; } /* * 0 1 2 3 * 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 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Service Path Identifier (SPI) | Service Index | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * */ ND_PRINT("service-path-id 0x%06x, ", GET_BE_U_3(bp)); bp += 3; ND_PRINT("service-index 0x%x", GET_U_1(bp)); bp += 1; /* * length includes the lengths of the Base and Service Path headers. * That means it must be at least 2. */ if (length < 2) { ND_PRINT(" (less than two headers)"); goto invalid; } /* * Print, or skip, the Context Headers. * (length - 2) is the length of those headers. */ if (ndo->ndo_vflag > 2) { u_int n; if (md_type == MD_TYPE1) { if (length != 6) { ND_PRINT(" (length for the MD type)"); goto invalid; } for (n = 0; n < length - 2; n++) { ND_PRINT("\n Context[%02u]: 0x%08x", n, GET_BE_U_4(bp)); bp += NSH_HDR_WORD_SIZE; } past_headers = 1; } else if (md_type == MD_TYPE2) { n = 0; while (n < length - 2) { uint16_t tlv_class; uint8_t tlv_type, tlv_len, tlv_len_padded; tlv_class = GET_BE_U_2(bp); bp += 2; tlv_type = GET_U_1(bp); bp += 1; tlv_len = GET_U_1(bp) & 0x7f; bp += 1; tlv_len_padded = roundup2(tlv_len, NSH_HDR_WORD_SIZE); ND_PRINT("\n TLV Class %u, Type %u, Len %u", tlv_class, tlv_type, tlv_len); n += 1; if (length - 2 < n + tlv_len_padded / NSH_HDR_WORD_SIZE) { ND_PRINT(" (length too big)"); goto invalid; } if (tlv_len) { const char *sep = "0x"; u_int vn; ND_PRINT("\n Value: "); for (vn = 0; vn < tlv_len; vn++) { ND_PRINT("%s%02x", sep, GET_U_1(bp)); bp += 1; sep = ":"; } /* Cover any TLV padding. */ ND_TCHECK_LEN(bp, tlv_len_padded - tlv_len); bp += tlv_len_padded - tlv_len; n += tlv_len_padded / NSH_HDR_WORD_SIZE; } } past_headers = 1; } } if (! past_headers) { ND_TCHECK_LEN(bp, (length - 2) * NSH_HDR_WORD_SIZE); bp += (length - 2) * NSH_HDR_WORD_SIZE; } ND_PRINT(ndo->ndo_vflag ? "\n " : ": "); /* print Next Protocol */ next_len = len - length * NSH_HDR_WORD_SIZE; switch (next_protocol) { case NP_IPV4: ip_print(ndo, bp, next_len); break; case NP_IPV6: ip6_print(ndo, bp, next_len); break; case NP_ETH: ether_print(ndo, bp, next_len, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL); break; default: ND_PRINT("ERROR: unknown-next-protocol"); return; } return; invalid: nd_print_invalid(ndo); }