Add support for split wiphy dump to Wireless Toolbar

To populate the Wireless Toolbar menu the NL80211_CMD_GET_WIPHY
command is used. Some network interfaces must use split wiphy dump
feature for this command to function properly. One such example is the
D-Link DWA-160 USB adapter that does not show up when used without.

Make use of split wiphy dump feature whenever kernel supports it
to populate the list of monitor interfaces for the Wireless Toolbar.

Bug: 10564
Change-Id: Idc28e92f91a2488fa48eeb282a0ef1e2bd40a5f0
Reviewed-on: https://code.wireshark.org/review/4611
Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>

2 files changed, 120 insertions, 24 deletions

diff --git a/caputils/ws80211_utils.c b/caputils/ws80211_utils.c
index 78f9cb721b..0e411c33a3 100644
--- a/caputils/ws80211_utils.c
+++ b/caputils/ws80211_utils.c
@@ -47,6 +47,10 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 #include <linux/nl80211.h>
 
+#ifdef HAVE_NL80211_SPLIT_WIPHY_DUMP
+static int ws80211_get_protocol_features(int* features);
+#endif /* HAVE_NL80211_SPLIT_WIPHY_DUMP */
+
 /* libnl 1.x compatibility code */
 #ifdef HAVE_LIBNL1
 #define nl_sock nl_handle
@@ -64,6 +68,7 @@ static inline void nl_socket_free(struct nl_sock *h)
 struct nl80211_state {
 	struct nl_sock *nl_sock;
 	int nl80211_id;
+	int have_split_wiphy;
 };
 
 static struct nl80211_state nl_state;
@@ -71,6 +76,9 @@ static struct nl80211_state nl_state;
 int ws80211_init(void)
 {
 	int err;
+#ifdef HAVE_NL80211_SPLIT_WIPHY_DUMP
+	int features = 0;
+#endif /* HAVE_NL80211_SPLIT_WIPHY_DUMP */
 
 	struct nl80211_state *state = &nl_state;
 
@@ -92,6 +100,11 @@ int ws80211_init(void)
 		err = -ENOENT;
 		goto out_handle_destroy;
 	}
+#ifdef HAVE_NL80211_SPLIT_WIPHY_DUMP
+	ws80211_get_protocol_features(&features);
+	if (features & NL80211_PROTOCOL_FEATURE_SPLIT_WIPHY_DUMP)
+		state->have_split_wiphy = TRUE;
+#endif /* HAVE_NL80211_SPLIT_WIPHY_DUMP */
 
 	return 0;
 
@@ -154,6 +167,21 @@ struct nliface_cookie
 	GArray *interfaces;
 };
 
+static struct ws80211_interface *
+	get_interface_by_name(GArray *interfaces,
+			      char* ifname)
+{
+	unsigned int i;
+	struct ws80211_interface *iface;
+
+	for (i = 0; i < interfaces->len; i++) {
+		iface = g_array_index(interfaces, struct ws80211_interface *, i);
+		if (!strcmp(iface->ifname, ifname))
+			return iface;
+	}
+	return NULL;
+}
+
 /*
  * And now for a steaming heap of suck.
  *
@@ -175,6 +203,43 @@ struct nliface_cookie
 #define nla_for_each_nested(pos, nla, rem) \
 	nla_for_each_attr(pos, (struct nlattr *)nla_data(nla), nla_len(nla), rem)
 
+#ifdef HAVE_NL80211_SPLIT_WIPHY_DUMP
+static int get_features_handler(struct nl_msg *msg, void *arg)
+{
+	int *feat = (int*) arg;
+	struct nlattr *tb_msg[NL80211_ATTR_MAX + 1];
+	struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlmsg_hdr(msg));
+
+	nla_parse(tb_msg, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
+		  genlmsg_attrlen(gnlh, 0), NULL);
+
+	if (tb_msg[NL80211_ATTR_PROTOCOL_FEATURES])
+		*feat = nla_get_u32(tb_msg[NL80211_ATTR_PROTOCOL_FEATURES]);
+
+	return NL_SKIP;
+}
+
+static int ws80211_get_protocol_features(int* features)
+{
+	struct nl_msg *msg;
+	struct nl_cb *cb;
+
+	msg = nlmsg_alloc();
+	if (!msg) {
+		fprintf(stderr, "failed to allocate netlink message\n");
+		return 2;
+	}
+
+	cb = nl_cb_alloc(NL_CB_DEFAULT);
+
+	genlmsg_put(msg, 0, 0, nl_state.nl80211_id, 0, 0,
+		    NL80211_CMD_GET_PROTOCOL_FEATURES, 0);
+
+	nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, get_features_handler, features);
+
+	return nl80211_do_cmd(msg, cb);
+}
+#endif /* HAVE_NL80211_SPLIT_WIPHY_DUMP */
 
 #ifdef NL80211_BAND_ATTR_HT_CAPA
 static void parse_band_ht_capa(struct ws80211_interface *iface,
@@ -193,20 +258,18 @@ static void parse_band_ht_capa(struct ws80211_interface *iface,
 }
 #endif /* NL80211_BAND_ATTR_HT_CAPA */
 
-static int parse_supported_iftypes(struct nlattr *tb)
+static void parse_supported_iftypes(struct ws80211_interface *iface,
+				    struct nlattr *tb)
 {
 	struct nlattr *nl_mode;
 	int rem_mode;
-	int cap_monitor = 0;
 
-	if (!tb) return 0;
+	if (!tb) return;
 
 	nla_for_each_nested(nl_mode, tb, rem_mode) {
 		if (nla_type(nl_mode) == NL80211_IFTYPE_MONITOR)
-			cap_monitor = 1;
+			iface->cap_monitor = 1;
 	}
-
-	return cap_monitor;
 }
 
 static void parse_band_freqs(struct ws80211_interface *iface,
@@ -291,41 +354,44 @@ static int get_phys_handler(struct nl_msg *msg, void *arg)
 	struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlmsg_hdr(msg));
 
 	struct nliface_cookie *cookie = (struct nliface_cookie *)arg;
+
 	struct ws80211_interface *iface;
-	int cap_monitor = 0;
+	char* ifname;
+	int added = 0;
 
 	nla_parse(tb_msg, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
 		  genlmsg_attrlen(gnlh, 0), NULL);
 
-	if (!tb_msg[NL80211_ATTR_WIPHY_BANDS])
-		return NL_SKIP;
-
-	cap_monitor = parse_supported_iftypes(tb_msg[NL80211_ATTR_SUPPORTED_IFTYPES]);
-
-	if (!cap_monitor)
-		return NL_SKIP;
-
-	iface = (struct ws80211_interface *)g_malloc0(sizeof(*iface));
-	if (!iface)
+	if (!tb_msg[NL80211_ATTR_WIPHY_NAME])
 		return NL_SKIP;
 
-	iface->frequencies = g_array_new(FALSE, FALSE, sizeof(int));
-	iface->channel_types = 1 << WS80211_CHAN_NO_HT;
+	ifname = g_strdup_printf("%s.mon", nla_get_string(tb_msg[NL80211_ATTR_WIPHY_NAME]));
+	iface = get_interface_by_name(cookie->interfaces, ifname);
 
-	if (tb_msg[NL80211_ATTR_WIPHY_NAME]) {
-		iface->ifname = g_strdup_printf("%s.mon",
-                nla_get_string(tb_msg[NL80211_ATTR_WIPHY_NAME]));
+	if (!iface) {
+		iface = (struct ws80211_interface *)g_malloc0(sizeof(*iface));
+		if (!iface) {
+			g_free(ifname);
+			return NL_SKIP;
+		}
+		added = 1;
+		iface->ifname = ifname;
+		iface->frequencies = g_array_new(FALSE, FALSE, sizeof(int));
+		iface->channel_types = 1 << WS80211_CHAN_NO_HT;
+	} else {
+		g_free(ifname);
 	}
 
+	parse_supported_iftypes(iface, tb_msg[NL80211_ATTR_SUPPORTED_IFTYPES]);
 	parse_wiphy_bands(iface, tb_msg[NL80211_ATTR_WIPHY_BANDS]);
 	parse_supported_commands(iface, tb_msg[NL80211_ATTR_SUPPORTED_COMMANDS]);
 
-	g_array_append_val(cookie->interfaces, iface);
+	if (added)
+		g_array_append_val(cookie->interfaces, iface);
 
 	return NL_SKIP;
 }
 
-
 static int ws80211_get_phys(GArray *interfaces)
 {
 	struct nliface_cookie cookie;
@@ -344,10 +410,20 @@ static int ws80211_get_phys(GArray *interfaces)
 	genlmsg_put(msg, 0, 0, nl_state.nl80211_id, 0,
 		    NLM_F_DUMP, NL80211_CMD_GET_WIPHY, 0);
 
+#ifdef HAVE_NL80211_SPLIT_WIPHY_DUMP
+	if (nl_state.have_split_wiphy) {
+		NLA_PUT_FLAG(msg, NL80211_ATTR_SPLIT_WIPHY_DUMP);
+	}
+#endif /* #ifdef HAVE_NL80211_SPLIT_WIPHY_DUMP */
 	nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, get_phys_handler, &cookie);
 
 	return nl80211_do_cmd(msg, cb);
 
+#ifdef HAVE_NL80211_SPLIT_WIPHY_DUMP
+nla_put_failure:
+	fprintf(stderr, "building message failed\n");
+	return -1;
+#endif /* HAVE_NL80211_SPLIT_WIPHY_DUMP */
 }
 
 static int get_freq_wext(const char *ifname)
@@ -478,6 +554,24 @@ int ws80211_get_iface_info(const char *name, struct ws80211_iface_info *iface_in
 	return __ws80211_get_iface_info(name, &__iface_info);
 }
 
+static int ws80211_keep_only_monitor(GArray *interfaces)
+{
+	unsigned int j;
+	struct ws80211_interface *iface;
+restart:
+	for (j = 0; j < interfaces->len; j++) {
+		iface = g_array_index(interfaces, struct ws80211_interface *, j);
+		if (!iface->cap_monitor) {
+			g_array_remove_index(interfaces, j);
+			g_array_free(iface->frequencies, TRUE);
+			g_free(iface->ifname);
+			g_free(iface);
+			goto restart;
+		}
+	}
+	return 0;
+}
+
 static int ws80211_populate_devices(GArray *interfaces)
 {
 	FILE *fh;
@@ -494,6 +588,7 @@ static int ws80211_populate_devices(GArray *interfaces)
 
 	/* Get a list of phy's that can handle monitor mode */
 	ws80211_get_phys(interfaces);
+	ws80211_keep_only_monitor(interfaces);
 
 	fh = g_fopen("/proc/net/dev", "r");
 	if(!fh) {
diff --git a/caputils/ws80211_utils.h b/caputils/ws80211_utils.h
index 2a6e04f629..7fcdc4477b 100644
--- a/caputils/ws80211_utils.h
+++ b/caputils/ws80211_utils.h
@@ -41,6 +41,7 @@ struct ws80211_interface
 	gboolean can_set_freq;
 	GArray *frequencies;
 	int channel_types; /* Union for all bands */
+	int cap_monitor;
 };
 
 struct ws80211_iface_info {