added `--list-libpcap-devices' to list al available pcap devices, output WinPCAP specific information at startup

Signed-off-by: Toni Uhlig <matzeton@googlemail.com>

4 files changed, 52 insertions, 7 deletions

diff --git a/configure.ac b/configure.ac
index 9e92922..5a6af52 100644
--- a/configure.ac
+++ b/configure.ac
@@ -113,6 +113,10 @@ struct foo {
 dnl Check for std functions.
 AC_CHECK_FUNCS([malloc calloc free memcpy memset printf sprintf vsnprintf strerror strlen strncmp strstr strtol strtoul fopen fprintf gettimeofday close fclose exit getopt_long],,
     [AC_MSG_ERROR([Missing essential std functions.])])
+if test x"${use_msw}" = x; then
+AC_CHECK_FUNCS([inet_ntoa],,
+    [AC_MSG_ERROR([Missing essential std functions.])])
+fi
 
 dnl `--disable-pcap`: Enabled if found.
 AC_ARG_ENABLE([pcap],
@@ -150,14 +154,14 @@ AC_MSG_RESULT([${with_rngdev}])
 AC_DEFINE_UNQUOTED([RNGDEV], ["${with_rngdev}"],
 	[set the path to the random device you want to use for pt_random])
 
-dnl Check libcap headers/functions.
+dnl Check libpcap headers/functions.
 if test x"${pcap_enabled}" != x -a \
         x"${use_msw}" != xyes; then
 	AC_CHECK_HEADERS([pcap.h],,
 	    [pcap_enabled=])
 	AC_SEARCH_LIBS([pcap_lookupnet], [pcap],,
 	    [pcap_enabled=],)
-	AC_CHECK_FUNCS([pcap_compile pcap_close pcap_setfilter pcap_dispatch],,
+	AC_CHECK_FUNCS([pcap_compile pcap_close pcap_setfilter pcap_dispatch pcap_findalldevs pcap_freealldevs],,
 	    [pcap_enabled=])
 fi
 
diff --git a/src/options.c b/src/options.c
index ad43380..ffb5339 100644
--- a/src/options.c
+++ b/src/options.c
@@ -113,6 +113,13 @@ static const struct option_usage usage[] = {
 #endif
 		"Enable libpcap on the given device.\n"
 	},
+	/** --list-libpcap-devices */
+	{NULL,           0, OPT_BOOL,   {.num = 0},
+#ifndef HAVE_PCAP
+		"(Not available on this platform.)\n"
+#endif
+		"List all available pcap devices.\n"
+	},
 	/** --logfile */
 	{"file",         0, OPT_STR,    {.str = "/var/log/ptunnel.log"},
 		"Specify a file to log to, rather than printing to standard out.\n"
@@ -219,11 +226,12 @@ static struct option long_options[] = {
 	{"connections", required_argument, 0, 'c'},
 	{"verbosity",   required_argument, 0, 'v'},
 	{"libpcap",     required_argument, 0, 'L'},
+	{"list-libpcap-devices", no_argument, &opts.list_pcap_devices, 1},
 	{"logfile",     optional_argument, 0, 'o'},
 	{"statistics",        no_argument, 0, 's'},
 	{"passwd",      required_argument, 0, 'P'},
-	{"udp",               no_argument, &opts.udp, 1 },
-	{"unprivileged",      no_argument, &opts.unprivileged, 1 },
+	{"udp",               no_argument, &opts.udp, 1},
+	{"unprivileged",      no_argument, &opts.unprivileged, 1},
 	{"window-size", required_argument, 0, 'w'},
 	{"ack-interval", required_argument, 0, 'a'},
 	{"resend-interval", required_argument, 0, 't'},
@@ -272,8 +280,6 @@ static void set_options_defaults(void) {
 	opts.log_path        = strdup(*(char **)get_default_optval(OPT_STR, "logfile"));
 	opts.log_file        = stdout;
 	opts.print_stats     = *(int *)       get_default_optval(OPT_BOOL,  "statistics");
-	opts.udp             = *(int *)       get_default_optval(OPT_BOOL,  "udp");
-	opts.unprivileged    = *(int *)       get_default_optval(OPT_BOOL,  "unprivileged");
 #ifndef WIN32
 	opts.pid_path        = strdup(*(char **)get_default_optval(OPT_STR, "daemon"));
 
diff --git a/src/options.h b/src/options.h
index 7afcfec..9585286 100644
--- a/src/options.h
+++ b/src/options.h
@@ -74,6 +74,8 @@ struct options {
 	int pcap;
 	/** Device to capture packets from */
 	char *pcap_device;
+	/** List all available pcap devices and exit */
+	int list_pcap_devices;
 #endif
 	/** Usually stdout, but can be altered by the user */
 	char *log_path;
diff --git a/src/ptunnel.c b/src/ptunnel.c
index 01e0ef5..5089eca 100644
--- a/src/ptunnel.c
+++ b/src/ptunnel.c
@@ -100,6 +100,31 @@ proxy_desc_t *chain = 0;
 const char *state_name[kNum_proto_types] = { "start", "ack  ", "data ",
                                              "close", "authenticate" };
 
+#ifdef HAVE_PCAP
+static void print_pcap_devices(void) {
+	pcap_if_t *devs, *cur_dev;
+	pcap_addr_t *cur_addr;
+	char errbuf[PCAP_ERRBUF_SIZE+1];
+
+	if (pcap_findalldevs(&devs, errbuf)) {
+		pt_log(kLog_error, "List all available pcap devices failed: %s.\n", errbuf);
+	}
+	printf("Available pcap devices:\n");
+	for (cur_dev = devs; cur_dev; cur_dev = cur_dev->next) {
+		if (cur_dev->description)
+			printf("\n\t%s%c '%s'\n", cur_dev->name, (cur_dev->addresses ? ':' : ' '),
+				cur_dev->description);
+		else
+			printf("\n\t%s%c\n", cur_dev->name, (cur_dev->addresses ? ':' : ' '));
+		for (cur_addr = cur_dev->addresses; cur_addr; cur_addr = cur_addr->next) {
+			if (cur_addr->addr->sa_family == AF_INET)
+				printf("\t\t%s\n", inet_ntoa(((struct sockaddr_in*)cur_addr->addr)->sin_addr));
+		}
+	}
+	pcap_freealldevs(devs);
+}
+#endif
+
 /* Let the fun begin! */
 int main(int argc, char *argv[]) {
 #ifndef WIN32
@@ -139,6 +164,11 @@ int main(int argc, char *argv[]) {
 	/* Init ptunnel RNG */
 	pt_random();
 
+	if (opts.list_pcap_devices) {
+		print_pcap_devices();
+		return 0;
+	}
+
 #ifdef HAVE_PCAP
 	if (opts.pcap && opts.udp) {
 		pt_log(kLog_error, "Packet capture is not supported (or needed) when using UDP for transport.\n");
@@ -146,7 +176,10 @@ int main(int argc, char *argv[]) {
 	}
 #ifdef WIN32
 	if (!opts.pcap && !opts.udp) {
-		pt_log(kLog_info, "WARNING: Running ptunnel-ng on Windows in ICMP mode without WinPcap enabled is not supported and may not work!\n");
+		pt_log(kLog_info, "Running ptunnel-ng on Windows in ICMP mode without WinPcap enabled is not supported and may not work!\n");
+        pt_log(kLog_info, "If you encounter problems, install WinPCAP from:\n");
+		pt_log(kLog_info, "https://www.winpcap.org/install/default.htm or for WIN10: https://nmap.org/npcap/windows-10.html\n");
+		pt_log(kLog_info, "After WinPCAP is installed, you can list pcap devices with: --list-pcap-devices\n");
 	}
 #endif
 #endif