extcap: add local_interfaces_to_list() to wsutil.

This new function abstracts the creation of a list of the local
interfaces that will be used by future extcaps to generate specific
filters. Sshdump now uses it to create a pcap filter.

Change-Id: I5b75a266f81104b3c9bcb3e51de246b7cc8785ce
Reviewed-on: https://code.wireshark.org/review/14092
Reviewed-by: João Valverde <j@v6e.pt>
Petri-Dish: João Valverde <j@v6e.pt>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Roland Knall <rknall@gmail.com>

4 files changed, 157 insertions, 0 deletions

diff --git a/wsutil/CMakeLists.txt b/wsutil/CMakeLists.txt
index 7d63757132..4a4d047c35 100644
--- a/wsutil/CMakeLists.txt
+++ b/wsutil/CMakeLists.txt
@@ -54,6 +54,7 @@ set(WSUTIL_FILES
 	frequency-utils.c
 	g711.c
 	inet_addr.c
+	interface.c
 	jsmn.c
 	md4.c
 	md5.c
diff --git a/wsutil/Makefile.common b/wsutil/Makefile.common
index 6e93833de2..38256f5228 100644
--- a/wsutil/Makefile.common
+++ b/wsutil/Makefile.common
@@ -51,6 +51,7 @@ LIBWSUTIL_COMMON_SRC = \
 	frequency-utils.c \
 	g711.c		\
 	inet_addr.c	\
+	interface.c	\
 	jsmn.c		\
 	md4.c		\
 	md5.c		\
@@ -102,6 +103,7 @@ libwsutil_nonrepl_INCLUDES = \
 	frequency-utils.h \
 	g711.h		\
 	inet_addr.h	\
+	interface.h	\
 	jsmn.h		\
 	md4.h		\
 	md5.h		\
diff --git a/wsutil/interface.c b/wsutil/interface.c
new file mode 100644
index 0000000000..07fdb318b5
--- /dev/null
+++ b/wsutil/interface.c
@@ -0,0 +1,106 @@
+/* interface.c
+ * Utility functions to get infos from interfaces
+ *
+ * Copyright 2016, Dario Lombardo
+ *
+ * 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 "interface.h"
+
+#include <string.h>
+#include <wsutil/inet_addr.h>
+
+#ifdef HAVE_ARPA_INET_H
+	#include <arpa/inet.h>
+#endif
+
+#ifdef HAVE_IFADDRS_H
+	#include <ifaddrs.h>
+#endif
+
+GSList *local_interfaces_to_list(void)
+{
+	GSList *interfaces = NULL;
+#ifdef HAVE_GETIFADDRS
+	struct ifaddrs *ifap;
+	struct ifaddrs *ifa;
+	int family;
+	char ip[INET6_ADDRSTRLEN];
+
+	if (getifaddrs(&ifap)) {
+		goto end;
+	}
+
+	interfaces = g_slist_alloc();
+
+	for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
+		if (ifa->ifa_addr == NULL)
+			continue;
+
+		family = ifa->ifa_addr->sa_family;
+
+		memset(ip, 0x0, INET6_ADDRSTRLEN);
+
+		switch (family) {
+			case AF_INET:
+				{
+					struct sockaddr_in *addr4 = (struct sockaddr_in *)ifa->ifa_addr;
+					ws_inet_ntop4(&addr4->sin_addr, ip, sizeof(ip));
+					break;
+				}
+
+			case AF_INET6:
+				{
+					struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)ifa->ifa_addr;
+					ws_inet_ntop6(&addr6->sin6_addr, ip, sizeof(ip));
+					break;
+				}
+
+			default:
+				break;
+		}
+
+		/* skip loopback addresses */
+		if (!g_strcmp0(ip, "127.0.0.1") || !g_strcmp0(ip, "::1"))
+			continue;
+
+		if (*ip) {
+			interfaces = g_slist_prepend(interfaces, g_strdup(ip));
+		}
+	}
+end:
+#endif /* HAVE_GETIFADDRS */
+	return interfaces;
+}
+
+/*
+ * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: t
+ * End:
+ *
+ * vi: set shiftwidth=4 tabstop=4 noexpandtab:
+ * :indentSize=4:tabSize=4:noTabs=false:
+ */
diff --git a/wsutil/interface.h b/wsutil/interface.h
new file mode 100644
index 0000000000..80205f4ea0
--- /dev/null
+++ b/wsutil/interface.h
@@ -0,0 +1,48 @@
+/* interface.c
+ * Utility functions to get infos from interfaces
+ *
+ * Copyright 2016, Dario Lombardo
+ *
+ * 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.
+ */
+
+#ifndef _INTERFACE_H
+#define _INTERFACE_H
+
+#include <glib.h>
+#include "ws_symbol_export.h"
+
+/* Return a list of IPv4/IPv6 addresses for local interfaces */
+WS_DLL_PUBLIC
+GSList* local_interfaces_to_list(void);
+
+#endif
+
+/*
+ * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: t
+ * End:
+ *
+ * vi: set shiftwidth=4 tabstop=4 noexpandtab:
+ * :indentSize=4:tabSize=4:noTabs=false:
+ */