Add GSMTAP logging sub-dissector

Applications can also use GSMTAP framing to convey log messages
which would traditionally be printed on stderr or on log files. This
allows the ordered/interspersed display of protocol messages with log
lines from the applications that send or received those messages.

The osmocom logging framework (part of libosmocore) implements this in
libosmocore.git Change-Id I9a7e72b8c9c6f6f2d76d1ea2332dcdee12394625

Change-Id: I0de723445e5b5ce0199a4081808111240a9ed047
Reviewed-on: https://code.wireshark.org/review/19183
Reviewed-by: Michael Mann <mmann78@netscape.net>
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>

7 files changed, 156 insertions, 0 deletions

diff --git a/docbook/release-notes.asciidoc b/docbook/release-notes.asciidoc
index 6a17064295..ec2fbe0a10 100644
--- a/docbook/release-notes.asciidoc
+++ b/docbook/release-notes.asciidoc
@@ -72,6 +72,7 @@ Snort Post-dissector
 Unified Diagnostic Services (UDS)
 vSocket
 Windows Cluster Management API (clusapi)
+GSMTAP based logging
 --sort-and-group--
 
 === Updated Protocol Support
diff --git a/epan/dissectors/.editorconfig b/epan/dissectors/.editorconfig
index 3ab2b2a04b..f0e6798899 100644
--- a/epan/dissectors/.editorconfig
+++ b/epan/dissectors/.editorconfig
@@ -945,6 +945,10 @@ indent_size = tab
 indent_style = tab
 indent_size = tab
 
+[packet-gsmtap_log.[ch]]
+indent_style = tab
+indent_size = tab
+
 [packet-gssapi.[ch]]
 indent_style = tab
 indent_size = tab
diff --git a/epan/dissectors/CMakeLists.txt b/epan/dissectors/CMakeLists.txt
index ca0bbd70e8..6385afa0a5 100644
--- a/epan/dissectors/CMakeLists.txt
+++ b/epan/dissectors/CMakeLists.txt
@@ -663,6 +663,7 @@ set(DISSECTOR_SRC
 	packet-gsm_sms_ud.c
 	packet-gsm_um.c
 	packet-gsmtap.c
+	packet-gsmtap_log.c
 	packet-gssapi.c
 	packet-gtp.c
 	packet-gtpv2.c
diff --git a/epan/dissectors/Makefile.am b/epan/dissectors/Makefile.am
index 4257b133ff..e021776f6c 100644
--- a/epan/dissectors/Makefile.am
+++ b/epan/dissectors/Makefile.am
@@ -685,6 +685,7 @@ DISSECTOR_SRC = \
 	packet-gsm_sms_ud.c	\
 	packet-gsm_um.c		\
 	packet-gsmtap.c		\
+	packet-gsmtap_log.c	\
 	packet-gssapi.c		\
 	packet-gtp.c		\
 	packet-gtpv2.c		\
diff --git a/epan/dissectors/packet-gsmtap.c b/epan/dissectors/packet-gsmtap.c
index dcd1fc41b8..c5ddd0539a 100644
--- a/epan/dissectors/packet-gsmtap.c
+++ b/epan/dissectors/packet-gsmtap.c
@@ -290,6 +290,7 @@ static const value_string gsmtap_types[] = {
 	{ GSMTAP_TYPE_GMR1_UM, "GMR-1 air interfeace (MES-MS<->GTS)" },
 	{ GSMTAP_TYPE_UMTS_RLC_MAC,	"UMTS RLC/MAC" },
 	{ GSMTAP_TYPE_UMTS_RRC,		"UMTS RRC" },
+	{ GSMTAP_TYPE_OSMOCORE_LOG,	"libosmocore logging" },
 	{ 0,			NULL },
 };
 
diff --git a/epan/dissectors/packet-gsmtap.h b/epan/dissectors/packet-gsmtap.h
index dced24940a..d22d89396d 100644
--- a/epan/dissectors/packet-gsmtap.h
+++ b/epan/dissectors/packet-gsmtap.h
@@ -46,6 +46,7 @@
 #define GSMTAP_TYPE_GMR1_UM		0x0a	/* GMR-1 L2 packets */
 #define GSMTAP_TYPE_UMTS_RLC_MAC	0x0b
 #define GSMTAP_TYPE_UMTS_RRC		0x0c
+#define GSMTAP_TYPE_OSMOCORE_LOG	0x10	/* libosmocore logging */
 
 /* ====== DO NOT MAKE UNAPPROVED MODIFICATIONS HERE ===== */
 #define GSMTAP_BURST_UNKNOWN		0x00
diff --git a/epan/dissectors/packet-gsmtap_log.c b/epan/dissectors/packet-gsmtap_log.c
new file mode 100644
index 0000000000..2958f2512a
--- /dev/null
+++ b/epan/dissectors/packet-gsmtap_log.c
@@ -0,0 +1,147 @@
+/* packet-gsmtap-log.c
+ * Routines for GSMTAP logging packets
+ *
+ * (C) 2016 by Harald Welte <laforge@gnumonks.org>
+ *
+ * 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 "packet-gsmtap.h"
+
+static int proto_gsmtap_log = -1;
+
+static int hf_log_ident = -1;
+static int hf_log_subsys = -1;
+static int hf_log_file_name = -1;
+static int hf_log_file_line = -1;
+static int hf_log_ts = -1;
+static int hf_log_pid = -1;
+static int hf_log_level = -1;
+static int hf_log_string = -1;
+
+static int ett_gsmtap_log = -1;
+
+/* from libosmocore include/osmocom/core/logging.h */
+static const value_string gsmtap_log_levels[] = {
+	{ 1,	"DEBUG" },
+	{ 3,	"INFO" },
+	{ 5,	"NOTICE" },
+	{ 7,	"ERROR" },
+	{ 8,	"FATAL" },
+	{ 0, NULL }
+};
+
+/* dissect a GSMTAP header and hand payload off to respective dissector */
+static int
+dissect_gsmtap_log(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void * data _U_)
+{
+	proto_item *ti;
+	proto_tree *log_tree;
+	gint offset = 0;
+	gint log_str_len;
+	guint log_pid, log_level, log_src_line;
+	const char *log_str;
+	const guint8 *log_ident, *log_subsys, *log_src_fname;
+
+	ti = proto_tree_add_item(tree, proto_gsmtap_log, tvb, 0, -1, ENC_NA);
+	log_tree = proto_item_add_subtree(ti, ett_gsmtap_log);
+
+	proto_tree_add_item(log_tree, hf_log_ts, tvb, offset, 8, ENC_TIME_NTP_BASE_ZERO|ENC_BIG_ENDIAN);
+	offset += 8;
+	proto_tree_add_item_ret_string(log_tree, hf_log_ident, tvb, offset, 16, ENC_NA, wmem_packet_scope(), &log_ident);
+	offset += 16;
+	proto_tree_add_item_ret_uint(log_tree, hf_log_pid, tvb, offset, 4, ENC_BIG_ENDIAN, &log_pid);
+	offset += 4;
+	proto_tree_add_item_ret_uint(log_tree, hf_log_level, tvb, offset++, 1, ENC_NA, &log_level);
+	offset += 3; /* pad octets */
+	proto_tree_add_item_ret_string(log_tree, hf_log_subsys, tvb, offset, 16, ENC_NA, wmem_packet_scope(), &log_subsys);
+	offset += 16;
+	proto_tree_add_item_ret_string(log_tree, hf_log_file_name, tvb, offset, 32, ENC_NA, wmem_packet_scope(), &log_src_fname);
+	offset += 32;
+	proto_tree_add_item_ret_uint(log_tree, hf_log_file_line, tvb, offset, 4, ENC_BIG_ENDIAN, &log_src_line);
+	offset += 4;
+
+	/* actual log message */
+	log_str_len = tvb_captured_length_remaining(tvb, offset);
+	proto_tree_add_item(log_tree, hf_log_string, tvb, offset, log_str_len, ENC_ASCII|ENC_NA);
+
+	log_str = tvb_format_stringzpad_wsp(tvb, offset, log_str_len);
+	col_append_str(pinfo->cinfo, COL_INFO, log_str);
+
+	proto_item_append_text(ti, " %s(%u): %s/%d: %s:%u %s",
+			log_ident, log_pid, log_subsys, log_level,
+			log_src_fname, log_src_line, log_str);
+	return tvb_captured_length(tvb);
+}
+
+void
+proto_register_gsmtap_log(void)
+{
+	static hf_register_info hf[] = {
+		{ &hf_log_ident, { "Application", "gsmtap_log.ident",
+		  FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL } },
+		{ &hf_log_subsys, { "Subsystem", "gsmtap_log.subsys",
+		  FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL } },
+		{ &hf_log_file_name, { "Source File Name", "gsmtap_log.src_file.name",
+		  FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL } },
+		{ &hf_log_file_line, { "Source File Line Number", "gsmtap_log.src_file.line_nr",
+		  FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL } },
+		{ &hf_log_ts, { "Timestamp", "gsmtap_log.timestamp",
+		  FT_ABSOLUTE_TIME, ABSOLUTE_TIME_UTC, NULL, 0, NULL, HFILL } },
+		{ &hf_log_pid, { "Process ID", "gsmtap_log.pid",
+		  FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL } },
+		{ &hf_log_level, { "Log Level", "gsmtap_log.level",
+		  FT_UINT8, BASE_DEC, VALS(gsmtap_log_levels), 0, NULL, HFILL } },
+		{ &hf_log_string, { "String", "gsmtap_log.string",
+		  FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL } },
+	};
+
+	static gint *ett[] = {
+		&ett_gsmtap_log,
+	};
+
+	proto_gsmtap_log = proto_register_protocol("GSMTAP libosmocore logging", "GSMTAP-LOG", "gsmtap_log");
+	proto_register_field_array(proto_gsmtap_log, hf, array_length(hf));
+	proto_register_subtree_array(ett, array_length(ett));
+}
+
+void
+proto_reg_handoff_gsmtap_log(void)
+{
+	dissector_handle_t gsmtap_log_handle;
+
+	gsmtap_log_handle = create_dissector_handle(dissect_gsmtap_log, proto_gsmtap_log);
+	dissector_add_uint("gsmtap.type", GSMTAP_TYPE_OSMOCORE_LOG, gsmtap_log_handle);
+}
+
+/*
+ * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 8
+ * tab-width: 8
+ * indent-tabs-mode: t
+ * End:
+ *
+ * vi: set shiftwidth=8 tabstop=8 noexpandtab:
+ * :indentSize=8:tabSize=8:noTabs=false:
+ */