From Juliusz Chroboczek via bug #5812: Dissector for the Babel Routing

Protocol (RFC 6126)


svn path=/trunk/; revision=36518

1 files changed, 523 insertions, 0 deletions

diff --git a/epan/dissectors/packet-babel.c b/epan/dissectors/packet-babel.c
new file mode 100644
index 0000000000..5724a41c38
--- /dev/null
+++ b/epan/dissectors/packet-babel.c
@@ -0,0 +1,523 @@
+/* packet-babel.c
+ * Routines for Babel dissection (RFC 6126)
+ * Copyright 2011 by Juliusz Chroboczek <jch@pps.jussieu.fr>
+ *
+ * $Id$
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <glib.h>
+
+#include <epan/packet.h>
+#include <epan/prefs.h>
+
+#include <stdio.h>
+
+void proto_reg_handoff_babel(void);
+
+static int proto_babel = -1;
+
+static gint ett_babel = -1;
+static int hf_babel_magic = -1;
+static int hf_babel_version = -1;
+static int hf_babel_bodylen = -1;
+
+static int hf_babel_message = -1;
+static gint ett_message = -1;
+static int hf_babel_message_type = -1;
+static int hf_babel_message_length = -1;
+static int hf_babel_message_nonce = -1;
+static int hf_babel_message_interval = -1;
+static int hf_babel_message_seqno = -1;
+static int hf_babel_message_ae = -1;
+static int hf_babel_message_prefix = -1;
+static int hf_babel_message_rxcost = -1;
+static int hf_babel_message_routerid = -1;
+static int hf_babel_message_flags = -1;
+static int hf_babel_message_plen = -1;
+static int hf_babel_message_omitted = -1;
+static int hf_babel_message_metric = -1;
+static int hf_babel_message_hopcount = -1;
+
+static gint ett_subtree = -1;
+
+#define UDP_PORT_BABEL 6697
+
+#define MESSAGE_PAD1 0
+#define MESSAGE_PADN 1
+#define MESSAGE_ACK_REQ 2
+#define MESSAGE_ACK 3
+#define MESSAGE_HELLO 4
+#define MESSAGE_IHU 5
+#define MESSAGE_ROUTER_ID 6
+#define MESSAGE_NH 7
+#define MESSAGE_UPDATE 8
+#define MESSAGE_REQUEST 9
+#define MESSAGE_MH_REQUEST 10
+
+static const value_string messages[] = {
+    { MESSAGE_PAD1, "pad1"},
+    { MESSAGE_PADN, "padn"},
+    { MESSAGE_ACK_REQ, "ack-req"},
+    { MESSAGE_ACK, "ack"},
+    { MESSAGE_HELLO, "hello"},
+    { MESSAGE_IHU, "ihu"},
+    { MESSAGE_ROUTER_ID, "router-id"},
+    { MESSAGE_NH, "nh"},
+    { MESSAGE_UPDATE, "update"},
+    { MESSAGE_REQUEST, "request"},
+    { MESSAGE_MH_REQUEST, "mh-request"},
+    { 0, NULL}
+};
+
+static const value_string aes[] = {
+    { 0, "Wildcard" },
+    { 1, "IPv4" },
+    { 2, "IPv6" },
+    { 3, "Link-Local IPv6"},
+    { 0, NULL }
+};
+
+/* The prefix for v6-mapped IPv4 addresses.  Format_address below 
+   returns IPv4 addresses in that format. */
+
+static const unsigned char v4prefix[16] =
+    {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
+
+/* The following two functions return ephemeral or constant strings, no
+   need to call free. */
+
+static const char *
+format_address(const unsigned char *prefix)
+{
+    if(prefix == NULL)
+        return "corrupt";
+    else if(memcmp(prefix, v4prefix, 12) == 0)
+        return ip_to_str(prefix + 12);
+    else
+        return ip6_to_str((const struct e_in6_addr*)prefix);
+}
+
+const char *
+format_prefix(const unsigned char *prefix, unsigned char plen)
+{
+    return ep_strdup_printf("%s/%u", format_address(prefix), plen);
+}
+
+static int
+network_prefix(int ae, int plen, unsigned int omitted,
+               const unsigned char *p, const unsigned char *dp,
+               unsigned int len, unsigned char *p_r)
+{
+    unsigned pb;
+    unsigned char prefix[16];
+
+    if(plen >= 0)
+        pb = (plen + 7) / 8;
+    else if(ae == 1)
+        pb = 4;
+    else
+        pb = 16;
+
+    if(pb > 16)
+        return -1;
+
+    memset(prefix, 0, 16);
+
+    switch(ae) {
+    case 0: break;
+    case 1:
+        if(omitted > 4 || pb > 4 || (pb > omitted && len < pb - omitted))
+            return -1;
+        memcpy(prefix, v4prefix, 12);
+        if(omitted) {
+            if (dp == NULL) return -1;
+            memcpy(prefix, dp, 12 + omitted);
+        }
+        if(pb > omitted) memcpy(prefix + 12 + omitted, p, pb);
+        break;
+    case 2:
+        if(omitted > 16 || (pb > omitted && len < pb - omitted))
+            return -1;
+        if(omitted) {
+            if (dp == NULL) return -1;
+            memcpy(prefix, dp, omitted);
+        }
+        if(pb > omitted) memcpy(prefix + omitted, p, pb - omitted);
+        break;
+    case 3:
+        if(pb > 8 && len < pb - 8) return -1;
+        prefix[0] = 0xfe;
+        prefix[1] = 0x80;
+        if(pb > 8) memcpy(prefix + 8, p, pb - 8);
+        break;
+    default:
+        return -1;
+    }
+
+    memcpy(p_r, prefix, 16);
+    return 1;
+}
+
+static int
+network_address(int ae, const unsigned char *a, unsigned int len,
+                unsigned char *a_r)
+{
+    return network_prefix(ae, -1, 0, a, NULL, len, a_r);
+}
+
+static int
+dissect_babel(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+    proto_item *ti;
+    unsigned char v4_prefix[16] = {0}, v6_prefix[16] = {0};
+    int i = 0;
+    proto_tree *babel_tree = NULL;
+    guint8 version;
+    guint16 bodylen;
+
+    if(tvb_length(tvb) < 4)
+        return 0;
+
+    if(tvb_get_guint8(tvb, 0) != 42)
+        return 0;
+    version = tvb_get_guint8(tvb, 1);
+
+    col_set_str(pinfo->cinfo, COL_PROTOCOL, "Babel");
+    col_set_str(pinfo->cinfo, COL_INFO, "Babel");
+
+    if(version != 2) {
+        col_add_fstr(pinfo->cinfo, COL_INFO, "Version %u", version);
+        return 2;
+    }
+        
+    if(tree) {
+        ti = proto_tree_add_item(tree, proto_babel, tvb, 0, -1, ENC_NA);
+        babel_tree = proto_item_add_subtree(ti, ett_babel);
+
+        proto_tree_add_item(babel_tree, hf_babel_magic, tvb, 0, 1, ENC_NA);
+        proto_tree_add_item(babel_tree, hf_babel_version, tvb, 1, 1, ENC_NA);
+        proto_tree_add_item(babel_tree, hf_babel_bodylen,
+                            tvb, 2, 2, ENC_BIG_ENDIAN);
+    }
+
+    bodylen = tvb_get_ntohs(tvb, 2);
+
+    i = 0;
+    while(i < bodylen) {
+        guint8 type, len = 0, total_length;
+        proto_tree *message_tree = NULL;
+        int message = 4 + i;
+
+        type = tvb_get_guint8(tvb, message);
+        if(type == MESSAGE_PAD1)
+            total_length = 1;
+        else {
+            len = tvb_get_guint8(tvb, message + 1);
+            total_length = len + 2;
+        }
+
+        col_append_fstr(pinfo->cinfo, COL_INFO, " %s",
+                        val_to_str(type, messages, "unknown"));
+
+        ti = proto_tree_add_uint_format(babel_tree, hf_babel_message,
+                                        tvb, message, total_length, type,
+                                        "Message %s (%u)",
+                                        val_to_str(type, messages,
+                                                   "unknown"),
+                                        type);
+
+        if(tree) {
+            message_tree = proto_item_add_subtree(ti, ett_message);
+            proto_tree_add_item(message_tree, hf_babel_message_type,
+                                tvb, message, 1, ENC_NA);
+        }
+
+        if(type == MESSAGE_PAD1) {
+            i++;
+            continue;
+        }
+
+        if(tree) {
+            proto_tree_add_item(message_tree, hf_babel_message_length,
+                                tvb, message + 1, 1, ENC_BIG_ENDIAN);
+
+            if(type == MESSAGE_PADN) {
+            } else if(type == MESSAGE_ACK_REQ) {
+                proto_tree_add_item(message_tree, hf_babel_message_nonce,
+                                    tvb, message + 4, 2, ENC_BIG_ENDIAN);
+                proto_tree_add_item(message_tree, hf_babel_message_interval,
+                                    tvb, message + 6, 2, ENC_BIG_ENDIAN);
+            } else if(type == MESSAGE_ACK) {
+                proto_tree_add_item(message_tree, hf_babel_message_nonce,
+                                    tvb, message + 2, 2, ENC_BIG_ENDIAN);
+            } else if(type == MESSAGE_HELLO) {
+                proto_tree_add_item(message_tree, hf_babel_message_seqno,
+                                    tvb, message + 4, 2, ENC_BIG_ENDIAN);
+                proto_tree_add_item(message_tree, hf_babel_message_interval,
+                                    tvb, message + 6, 2, ENC_BIG_ENDIAN);
+            } else if(type == MESSAGE_IHU) {
+                proto_tree *subtree;
+                unsigned char address[16];
+                int rc =
+                    network_address(tvb_get_guint8(tvb, message + 2),
+                                    tvb_get_ptr(tvb, message + 8, len - 6),
+                                    len - 6,
+                                    address);
+                proto_tree_add_item(message_tree, hf_babel_message_rxcost,
+                                    tvb, message + 4, 2, ENC_BIG_ENDIAN);
+                proto_tree_add_item(message_tree, hf_babel_message_interval,
+                                    tvb, message + 6, 2, ENC_BIG_ENDIAN);
+                ti = proto_tree_add_text(message_tree,
+                                         tvb, message + 4, len - 2,
+                                         "Address: %s",
+                                         format_address(rc < 0 ?
+                                                        NULL : address));
+                subtree = proto_item_add_subtree(ti, ett_subtree);
+                proto_tree_add_item(subtree, hf_babel_message_ae,
+                                    tvb, message + 2, 1, ENC_NA);
+                proto_tree_add_item(subtree, hf_babel_message_prefix,
+                                    tvb, message + 4, len - 2, ENC_NA);
+            } else if(type == MESSAGE_ROUTER_ID) {
+                proto_tree_add_item(message_tree, hf_babel_message_routerid,
+                                    tvb, message + 4, 8, ENC_NA);
+            } else if(type == MESSAGE_NH) {
+                proto_tree *subtree;
+                unsigned char nh[16];
+                int rc =
+                    network_address(tvb_get_guint8(tvb, message + 2),
+                                    tvb_get_ptr(tvb, message + 4, len - 2),
+                                    len - 2,
+                                    nh);
+                ti = proto_tree_add_text(message_tree,
+                                         tvb, message + 4, len - 2,
+                                         "NH: %s",
+                                         format_address(rc < 0 ? NULL : nh));
+                subtree = proto_item_add_subtree(ti, ett_subtree);
+                proto_tree_add_item(subtree, hf_babel_message_ae,
+                                    tvb, message + 2, 1, ENC_NA);
+                proto_tree_add_item(subtree, hf_babel_message_prefix,
+                                    tvb, message + 4, len - 2, ENC_NA);
+            } else if(type == MESSAGE_UPDATE) {
+                proto_tree *subtree;
+                unsigned char p[16];
+                guint8 ae = tvb_get_guint8(tvb, message + 2);
+                guint8 flags = tvb_get_guint8(tvb, message + 3);
+                guint8 plen = tvb_get_guint8(tvb, message + 4);
+                int rc =
+                    network_prefix(ae, plen,
+                                   tvb_get_guint8(tvb, message + 5),
+                                   tvb_get_ptr(tvb, message + 12, len - 10),
+                                   ae == 1 ? v4_prefix : v6_prefix,
+                                   len - 10, p);
+                if(rc >= 0 && (flags & 0x80)) {
+                    if(ae == 1)
+                        memcpy(v4_prefix, p, 16);
+                    else
+                        memcpy(v6_prefix, p, 16);
+                }
+
+                proto_tree_add_item(message_tree, hf_babel_message_flags,
+                                    tvb, message + 3, 1, ENC_NA);
+                proto_tree_add_item(message_tree, hf_babel_message_interval,
+                                    tvb, message + 6, 2, ENC_BIG_ENDIAN);
+                proto_tree_add_item(message_tree, hf_babel_message_seqno,
+                                    tvb, message + 8, 2, ENC_BIG_ENDIAN);
+                proto_tree_add_item(message_tree, hf_babel_message_metric,
+                                    tvb, message + 10, 2, ENC_BIG_ENDIAN);
+                ti = proto_tree_add_text(message_tree,
+                                         tvb, message + 12, len - 10,
+                                         "Prefix: %s",
+                                         format_prefix(rc < 0 ? NULL : p,
+                                                       plen));
+                subtree = proto_item_add_subtree(ti, ett_subtree);
+                proto_tree_add_item(subtree, hf_babel_message_ae,
+                                    tvb, message + 2, 1, ENC_NA);
+                proto_tree_add_item(subtree, hf_babel_message_plen,
+                                    tvb, message + 4, 1, ENC_NA);
+                proto_tree_add_item(subtree, hf_babel_message_omitted,
+                                    tvb, message + 5, 1, ENC_NA);
+                proto_tree_add_item(subtree, hf_babel_message_prefix,
+                                    tvb, message + 12, len - 10, ENC_NA);
+            } else if(type == MESSAGE_REQUEST) {
+                proto_tree *subtree;
+                unsigned char p[16];
+                guint8 plen = tvb_get_guint8(tvb, message + 3);
+                int rc =
+                    network_prefix(tvb_get_guint8(tvb, message + 2), plen,
+                                   0,
+                                   tvb_get_ptr(tvb, message + 4, len - 2),
+                                   NULL,
+                                   len - 2, p);
+                ti = proto_tree_add_text(message_tree,
+                                         tvb, message + 4, len - 2,
+                                         "Prefix: %s",
+                                         format_prefix(rc < 0 ? NULL : p,
+                                                       plen));
+                subtree = proto_item_add_subtree(ti, ett_subtree);
+                proto_tree_add_item(subtree, hf_babel_message_ae,
+                                    tvb, message + 2, 1, ENC_NA);
+                proto_tree_add_item(subtree, hf_babel_message_plen,
+                                    tvb, message + 3, 1, ENC_NA);
+                proto_tree_add_item(subtree, hf_babel_message_prefix,
+                                    tvb, message + 4, len - 2, ENC_NA);
+            } else if(type == MESSAGE_MH_REQUEST) {
+                proto_tree *subtree;
+                unsigned char p[16];
+                guint8 plen = tvb_get_guint8(tvb, message + 3);
+                int rc =
+                    network_prefix(tvb_get_guint8(tvb, message + 2), plen,
+                                   0,
+                                   tvb_get_ptr(tvb, message + 16, len - 14),
+                                   NULL,
+                                   len - 14, p);
+                proto_tree_add_item(message_tree, hf_babel_message_seqno,
+                                    tvb, message + 4, 2, ENC_BIG_ENDIAN);
+                proto_tree_add_item(message_tree, hf_babel_message_hopcount,
+                                    tvb, message + 6, 1, ENC_NA);
+                proto_tree_add_item(message_tree, hf_babel_message_routerid,
+                                    tvb, message + 8, 8, ENC_NA);
+                ti = proto_tree_add_text(message_tree,
+                                         tvb, message + 16, len - 14,
+                                         "Prefix: %s",
+                                         format_prefix(rc < 0 ? NULL : p,
+                                                       plen));
+                subtree = proto_item_add_subtree(ti, ett_subtree);
+                proto_tree_add_item(subtree, hf_babel_message_ae,
+                                    tvb, message + 2, 1, ENC_NA);
+                proto_tree_add_item(subtree, hf_babel_message_plen,
+                                    tvb, message + 3, 1, ENC_NA);
+                proto_tree_add_item(subtree, hf_babel_message_prefix,
+                                    tvb, message + 16, len - 14, ENC_NA);
+            }
+        }
+        i += len + 2;
+    }
+    return i;
+}
+
+void
+proto_register_babel(void)
+{
+    static hf_register_info hf[] = {
+        { &hf_babel_magic,
+          { "Magic", "babel.magic", FT_UINT8, BASE_DEC,
+            NULL, 0, "Magic value 42", HFILL }
+        },
+        { &hf_babel_version,
+          { "Version", "babel.version", FT_UINT8, BASE_DEC,
+            NULL, 0, "Version of the Babel protocol", HFILL }
+        },
+        { &hf_babel_bodylen,
+          { "Body Length", "babel.bodylen", FT_UINT16, BASE_DEC,
+            NULL, 0, NULL, HFILL }
+        },
+        { &hf_babel_message,
+          { "Message", "babel.message", FT_UINT8, BASE_DEC,
+            NULL, 0, "Babel Message", HFILL }
+        },
+        { &hf_babel_message_type,
+          { "Message Type", "babel.message.type", FT_UINT8, BASE_DEC,
+            VALS(messages), 0, NULL, HFILL }
+        },
+        { &hf_babel_message_length,
+          { "Message Length", "babel.message.length", FT_UINT8, BASE_DEC,
+            NULL, 0, NULL, HFILL }
+        },
+        { &hf_babel_message_nonce,
+          { "Nonce", "babel.message.nonce", FT_UINT16, BASE_HEX,
+           NULL, 0, NULL, HFILL }
+        },
+        { &hf_babel_message_interval,
+          { "Interval", "babel.message.interval", FT_UINT16, BASE_DEC,
+           NULL, 0, "Interval (in centiseconds)", HFILL }
+        },
+        { &hf_babel_message_seqno,
+          { "Seqno", "babel.message.seqno", FT_UINT16, BASE_HEX,
+           NULL, 0, NULL, HFILL }
+        },
+        { &hf_babel_message_ae,
+          { "Address Encoding", "babel.message.ae", FT_UINT8, BASE_DEC,
+            VALS(aes), 0, NULL, HFILL }
+        },
+        { &hf_babel_message_prefix,
+          { "Raw Prefix", "babel.message.prefix", FT_BYTES, BASE_NONE,
+            NULL, 0, NULL, HFILL }
+        },
+        { &hf_babel_message_rxcost,
+          { "Rxcost", "babel.message.rxcost", FT_UINT16, BASE_HEX,
+           NULL, 0, "Rxcost (from the point of vue of the sender)", HFILL }
+        },
+        { &hf_babel_message_routerid,
+          { "Router ID", "babel.message.routerid", FT_BYTES, BASE_NONE,
+           NULL, 0, NULL, HFILL }
+        },
+        { &hf_babel_message_flags,
+          { "Flags", "babel.message.flags", FT_UINT8, BASE_HEX,
+            NULL, 0, NULL, HFILL }
+        },
+        { &hf_babel_message_plen,
+          { "Prefix Length", "babel.message.plen", FT_UINT8, BASE_DEC,
+            NULL, 0, NULL, HFILL }
+        },
+        { &hf_babel_message_omitted,
+          { "Omitted Bytes", "babel.message.omitted", FT_UINT8, BASE_DEC,
+            NULL, 0, "Number of bytes omitted from the prefix", HFILL }
+        },
+        { &hf_babel_message_metric,
+          { "Metric", "babel.message.metric", FT_UINT16, BASE_DEC,
+           NULL, 0, NULL, HFILL }
+        },
+        { &hf_babel_message_hopcount,
+          { "Hop Count", "babel.message.omitted", FT_UINT8, BASE_DEC,
+            NULL, 0, NULL, HFILL }
+        },
+    };
+
+    static gint *ett[] = {
+        &ett_babel,
+        &ett_message,
+        &ett_subtree,
+    };
+
+    module_t *babel_module;
+
+    proto_babel =
+        proto_register_protocol("Babel Routing Protocol", "Babel", "babel");
+
+    proto_register_field_array(proto_babel, hf, array_length(hf));
+    proto_register_subtree_array(ett, array_length(ett));
+
+    babel_module = prefs_register_protocol(proto_babel,
+                                           proto_reg_handoff_babel);
+}
+
+void
+proto_reg_handoff_babel(void)
+{
+    dissector_handle_t babel_handle;
+
+    babel_handle = new_create_dissector_handle(dissect_babel, proto_babel);
+    dissector_add_uint("udp.port", UDP_PORT_BABEL, babel_handle);
+}