Add Local Service Discovery (LSD) protocol

Bug: 12985
Change-Id: Iceacd3d122337091380d56bd7fa9875bf7cb4d47
Reviewed-on: https://code.wireshark.org/review/18134
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Michael Mann <mmann78@netscape.net>

1 files changed, 207 insertions, 0 deletions

diff --git a/epan/dissectors/packet-lsd.c b/epan/dissectors/packet-lsd.c
new file mode 100644
index 0000000000..f8a667b2f8
--- /dev/null
+++ b/epan/dissectors/packet-lsd.c
@@ -0,0 +1,207 @@
+/* packet-lsd.c
+ * Local Service Discovery packet dissector
+ *
+ * From http://bittorrent.org/beps/bep_0014.html
+ *
+ * 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.
+ */
+
+#include "config.h"
+
+#include <epan/packet.h>
+#include <epan/expert.h>
+#include <wsutil/strtoi.h>
+
+void proto_register_lsd(void);
+void proto_reg_handoff_lsd(void);
+
+#define LSD_MULTICAST_ADDRESS 0xEFC0988F /* 239.192.152.143 */
+#define LSD_PORT 6771
+
+static int proto_lsd = -1;
+static int hf_lsd_header = -1;
+static int hf_lsd_host = -1;
+static int hf_lsd_port = -1;
+static int hf_lsd_infohash = -1;
+
+static gint ett_lsd = -1;
+
+static expert_field ei_lsd_field = EI_INIT;
+
+static gboolean
+parse_string_field(proto_tree *tree, int hf, packet_info *pinfo, tvbuff_t *tvb, int offset, int* next_offset, int* linelen)
+{
+  guint8 *str;
+  header_field_info* hf_info = proto_registrar_get_nth(hf);
+  gchar **field_and_value;
+  proto_item* ti;
+  gchar *p;
+
+  *linelen = tvb_find_line_end(tvb, offset, -1, next_offset, FALSE);
+  if (*linelen < 0)
+    return FALSE;
+
+  str = tvb_get_string_enc(wmem_packet_scope(), tvb, offset, *linelen, ENC_ASCII);
+  if (g_ascii_strncasecmp(str, hf_info->name, strlen(hf_info->name)) == 0)
+  {
+      field_and_value = wmem_strsplit(wmem_packet_scope(), str, ":", 1);
+      p = field_and_value[1];
+      while(g_ascii_isspace(*p))
+          p++;
+      proto_tree_add_string(tree, hf, tvb, offset, *linelen, p);
+  }
+  else
+  {
+    ti = proto_tree_add_string_format(tree, hf, tvb, offset, *linelen, str, "%s", str);
+    expert_add_info_format(pinfo, ti, &ei_lsd_field, "%s field malformed", hf_info->name);
+  }
+
+  return TRUE;
+}
+
+static int
+dissect_lsd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
+{
+  proto_item *ti = NULL;
+  proto_tree *lsd_tree;
+  int offset = 0, next_offset = 0, linelen;
+  guint8 *str;
+  gchar **field_and_value;
+  guint16 port;
+  gboolean valid;
+
+  linelen = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
+  if (linelen < 0)
+      return 0;
+
+  col_set_str(pinfo->cinfo, COL_PROTOCOL, "LSD");
+  col_clear(pinfo->cinfo, COL_INFO);
+
+  /* Create display subtree for the protocol */
+  ti = proto_tree_add_item(tree, proto_lsd, tvb, 0, -1, ENC_NA);
+  lsd_tree = proto_item_add_subtree(ti, ett_lsd);
+
+  proto_tree_add_item(lsd_tree, hf_lsd_header, tvb, offset, linelen, ENC_ASCII|ENC_NA);
+
+  offset = next_offset;
+  if (!parse_string_field(lsd_tree, hf_lsd_host, pinfo, tvb, offset, &next_offset, &linelen))
+      return offset+linelen;
+
+  offset = next_offset;
+  linelen = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
+  if (linelen < 0)
+      return offset+linelen;
+  str = tvb_get_string_enc(wmem_packet_scope(), tvb, offset, linelen, ENC_ASCII);
+  if (g_ascii_strncasecmp(str, "Port", strlen("Port")) == 0)
+  {
+    field_and_value = wmem_strsplit(wmem_packet_scope(), str, ":", 1);
+    valid = ws_strtou16(field_and_value[1], NULL, &port);
+    ti = proto_tree_add_uint(lsd_tree, hf_lsd_port, tvb, offset, linelen, port);
+    if (!valid)
+    {
+      expert_add_info_format(pinfo, ti, &ei_lsd_field, "Port value malformed");
+    }
+  }
+  else
+  {
+    ti = proto_tree_add_uint(lsd_tree, hf_lsd_port, tvb, offset, 0, 0xFFFF);
+    expert_add_info_format(pinfo, ti, &ei_lsd_field, "Port field malformed");
+  }
+  proto_item_set_len(ti, linelen);
+
+  offset = next_offset;
+  if (!parse_string_field(lsd_tree, hf_lsd_infohash, pinfo, tvb, offset, &next_offset, &linelen))
+      return offset+linelen;
+
+  return tvb_captured_length(tvb);
+}
+
+static gboolean
+dissect_lsd_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
+{
+  if (pinfo->dst.type != AT_IPv4)
+      return FALSE;
+
+  if (g_ntohl((*((const guint32 *)pinfo->dst.data))) != LSD_MULTICAST_ADDRESS)
+      return FALSE;
+
+  if (pinfo->destport != LSD_PORT)
+      return FALSE;
+
+  return (dissect_lsd(tvb, pinfo, tree, data) != 0);
+}
+
+void
+proto_register_lsd(void)
+{
+  static hf_register_info hf[] = {
+    { &hf_lsd_header,
+      { "Header", "lsd.header",
+        FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL }
+    },
+    { &hf_lsd_host,
+      { "Host", "lsd.host",
+        FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL }
+    },
+    { &hf_lsd_port,
+      { "Port", "lsd.port",
+        FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL }
+    },
+    { &hf_lsd_infohash,
+      { "Infohash", "lsd.infohash",
+        FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL }
+    },
+  };
+
+  static gint *ett[] = {
+    &ett_lsd,
+  };
+
+  static ei_register_info ei[] = {
+    { &ei_lsd_field, { "lsd.malformed_field", PI_MALFORMED, PI_ERROR, "Malformed LDS field", EXPFILL }},
+  };
+
+  expert_module_t* expert_lsd;
+
+  proto_lsd = proto_register_protocol("Local Service Discovery", "LSD", "lsd");
+
+  proto_register_field_array(proto_lsd, hf, array_length(hf));
+  proto_register_subtree_array(ett, array_length(ett));
+  expert_lsd = expert_register_protocol(proto_lsd);
+  expert_register_field_array(expert_lsd, ei, array_length(ei));
+}
+
+void
+proto_reg_handoff_lsd(void)
+{
+    heur_dissector_add( "udp", dissect_lsd_heur, "LSD over UDP", "lsd_udp", proto_lsd, HEURISTIC_ENABLE);
+}
+
+/*
+ * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
+ *
+ * Local Variables:
+ * c-basic-offset: 2
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * ex: set shiftwidth=2 tabstop=8 expandtab:
+ * :indentSize=2:tabSize=8:noTabs=true:
+ */