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-rw-r--r--print-nsh.c264
1 files changed, 264 insertions, 0 deletions
diff --git a/print-nsh.c b/print-nsh.c
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+/* 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 */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#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(" (invalid 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);
+}
+