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-rw-r--r--epan/dissectors/packet-bier.c250
1 files changed, 250 insertions, 0 deletions
diff --git a/epan/dissectors/packet-bier.c b/epan/dissectors/packet-bier.c
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+++ b/epan/dissectors/packet-bier.c
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+/* @file
+ * Routines for Bit Index Explicit Replication (BIER) dissection
+ *
+ * Copyright 2024, John Thacker <johnthacker@gmail.com>
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * RFC 8296: https://www.rfc-editor.org/rfc/rfc8296.html
+ */
+
+#include "config.h"
+
+#include <epan/packet.h>
+
+void proto_register_bier(void);
+void proto_reg_handoff_bier(void);
+
+static int proto_bier;
+
+static int hf_bier_nibble;
+static int hf_bier_ver;
+static int hf_bier_bsl;
+static int hf_bier_entropy;
+static int hf_bier_oam;
+static int hf_bier_rsv;
+static int hf_bier_dscp;
+static int hf_bier_proto;
+static int hf_bier_bfir_id;
+static int hf_bier_bitstring;
+
+static int ett_bier;
+
+static dissector_table_t bier_subdissector_table;
+
+static dissector_handle_t bier_handle;
+
+static const value_string bier_bsl_vals[] = {
+ { 1, "64 bits" },
+ { 2, "128 bits" },
+ { 3, "256 bits" },
+ { 4, "512 bits" },
+ { 5, "1024 bits" },
+ { 6, "2048 bits" },
+ { 7, "4096 bits" },
+ { 0, NULL }
+};
+
+// https://www.iana.org/assignments/bier/bier.xhtml#bier-next-protocol-identifiers
+static const value_string bier_proto_vals[] = {
+ { 0, "Reserved" },
+ { 1, "MPLS packet with downstream-assigned label at top of stack" },
+ { 2, "MPLS packet with upstream-assigned label at top of stack" },
+ { 3, "Ethernet frame" },
+ { 4, "IPv4 packet" },
+ { 5, "OAM packet" },
+ { 6, "IPv6 packet" },
+ { 7, "Payload is VXLAN encapsulated (no IP/UDP header)" },
+ { 8, "Payload is NVGRE encapsulated (no IP header)" },
+ { 9, "Payload is GENEVE encapsulated (no IP/UDP header)" },
+ { 63, "Reserved" },
+ { 0, NULL }
+};
+
+static int
+dissect_bier(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, void* data _U_)
+{
+ proto_item *ti;
+ proto_tree *bier_tree;
+
+ unsigned offset = 0;
+ uint32_t proto;
+ tvbuff_t *next_tvb;
+
+ if (tvb_reported_length(tvb) < 16) {
+ return 0;
+ }
+
+ if (tvb_captured_length(tvb) < 2) {
+ return 0;
+ }
+
+ /* This nibble is ignored in non-MPLS */
+ if (((tvb_get_uint8(tvb, 0) >> 4) & 0xF) != 0x5) {
+ return 0;
+ }
+
+ uint8_t bsl = (tvb_get_uint8(tvb, 1) >> 4) & 0xF;
+ if (bsl == 0 || bsl > 7) {
+ return 0;
+ }
+
+ int bitstring_length = 1 << (bsl + 2);
+
+ if (tvb_reported_length_remaining(tvb, 8) < bitstring_length) {
+ return 0;
+ }
+
+ col_set_str(pinfo->cinfo, COL_PROTOCOL, "BIER");
+ col_clear(pinfo->cinfo, COL_INFO);
+
+ ti = proto_tree_add_item(tree, proto_bier, tvb, offset, 8 + bitstring_length, ENC_NA);
+
+ bier_tree = proto_item_add_subtree(ti, ett_bier);
+
+ proto_tree_add_item(bier_tree, hf_bier_nibble, tvb, offset, 1, ENC_NA);
+ proto_tree_add_item(bier_tree, hf_bier_ver, tvb, offset, 1, ENC_NA);
+ offset += 1;
+
+ proto_tree_add_item(bier_tree, hf_bier_bsl, tvb, offset, 1, ENC_NA);
+ proto_tree_add_item(bier_tree, hf_bier_entropy, tvb, offset, 3, ENC_BIG_ENDIAN);
+ offset += 3;
+
+ proto_tree_add_item(bier_tree, hf_bier_oam, tvb, offset, 1, ENC_NA);
+ proto_tree_add_item(bier_tree, hf_bier_rsv, tvb, offset, 1, ENC_NA);
+ /* DSCP field unused in MPLS; may be as IP DSCP in non-MPLS. */
+ proto_tree_add_item(bier_tree, hf_bier_dscp, tvb, offset, 2, ENC_BIG_ENDIAN);
+ offset += 1;
+
+ proto_tree_add_item_ret_uint(bier_tree, hf_bier_proto, tvb, offset, 1, ENC_NA, &proto);
+ col_add_str(pinfo->cinfo, COL_INFO, val_to_str_wmem(pinfo->pool, proto, bier_proto_vals, "Unknown (0x%02x)"));
+ offset += 1;
+
+ proto_tree_add_item(bier_tree, hf_bier_bfir_id, tvb, offset, 2, ENC_BIG_ENDIAN);
+ offset += 2;
+
+ proto_tree_add_item(bier_tree, hf_bier_bitstring, tvb, offset, bitstring_length, ENC_NA);
+ offset += bitstring_length;
+
+ next_tvb = tvb_new_subset_remaining(tvb, offset);
+ if (!dissector_try_uint(bier_subdissector_table, proto, next_tvb, pinfo, tree)) {
+ call_data_dissector(next_tvb, pinfo, tree);
+ }
+
+ return tvb_captured_length(tvb);
+}
+
+void
+proto_register_bier(void)
+{
+ static hf_register_info hf[] = {
+ {
+ &hf_bier_nibble,
+ {
+ "Nibble", "bier.nibble", FT_UINT8,
+ BASE_HEX, NULL, 0xF0, NULL, HFILL
+ }
+ },
+ {
+ &hf_bier_ver,
+ {
+ "Version", "bier.ver", FT_UINT8,
+ BASE_DEC, NULL, 0x0F, NULL, HFILL
+ }
+ },
+ {
+ &hf_bier_bsl,
+ {
+ "BitString Length", "bier.bsl", FT_UINT8,
+ BASE_DEC, VALS(bier_bsl_vals), 0xF0, NULL, HFILL
+ }
+ },
+ {
+ &hf_bier_entropy,
+ {
+ "Entropy", "bier.entropy", FT_UINT24,
+ BASE_HEX, NULL, 0x0FFFFF, NULL, HFILL
+ }
+ },
+ {
+ &hf_bier_oam,
+ {
+ "OAM", "bier.oam", FT_UINT8,
+ BASE_HEX, NULL, 0xC0, NULL, HFILL
+ }
+ },
+ {
+ &hf_bier_rsv,
+ {
+ "Rsv", "bier.rsv", FT_UINT8,
+ BASE_HEX, NULL, 0x30, NULL, HFILL
+ }
+ },
+ {
+ &hf_bier_dscp,
+ {
+ "DSCP", "bier.dscp", FT_UINT16,
+ BASE_HEX, NULL, 0x0FC0, NULL, HFILL
+ }
+ },
+ {
+ &hf_bier_proto,
+ {
+ "Next Protocol", "bier.proto", FT_UINT8,
+ BASE_HEX, VALS(bier_proto_vals), 0x3F, NULL, HFILL
+ }
+ },
+ {
+ &hf_bier_bfir_id,
+ {
+ "BFIR-id", "bier.bfir-id", FT_UINT16,
+ BASE_DEC, NULL, 0x0, NULL, HFILL
+ }
+ },
+ {
+ &hf_bier_bitstring,
+ {
+ "BitString", "bier.bitstring", FT_BYTES,
+ BASE_NONE, NULL, 0x0, NULL, HFILL
+ }
+ },
+ };
+
+ static int *ett[] = {
+ &ett_bier
+ };
+
+ proto_bier =
+ proto_register_protocol("Bit Index Explicit Replication", "BIER", "bier");
+
+ proto_register_field_array(proto_bier, hf, array_length(hf));
+ proto_register_subtree_array(ett, array_length(ett));
+ bier_handle = register_dissector_with_description("bier.mpls", "BIER encapsulated in MPLS", dissect_bier, proto_bier);
+
+ bier_subdissector_table = register_dissector_table("bier.proto",
+ "BIER Next Protocol", proto_bier, FT_UINT8, BASE_DEC);
+}
+
+void
+proto_reg_handoff_bier(void)
+{
+ dissector_handle_t mpls_handle = find_dissector_add_dependency("mpls", proto_bier);
+
+ dissector_add_for_decode_as("mpls.label", bier_handle);
+
+ dissector_add_uint("mpls.pfn", 5, bier_handle);
+
+ dissector_add_uint("bier.proto", 1, mpls_handle);
+ dissector_add_uint("bier.proto", 2, mpls_handle);
+ dissector_add_uint("bier.proto", 3, find_dissector_add_dependency("eth_maybefcs", proto_bier));
+ dissector_add_uint("bier.proto", 4, find_dissector_add_dependency("ip", proto_bier));
+ /* 5 is BIER OAM - https://datatracker.ietf.org/doc/draft-ietf-bier-ping/ */
+ dissector_add_uint("bier.proto", 6, find_dissector_add_dependency("ipv6", proto_bier));
+ dissector_add_uint("bier.proto", 7, find_dissector_add_dependency("vxlan", proto_bier));
+ dissector_add_uint("bier.proto", 8, find_dissector_add_dependency("gre", proto_bier));
+ dissector_add_uint("bier.proto", 9, find_dissector_add_dependency("geneve", proto_bier));
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-27 10:13:27 +0000