hotspot: allow roaming consortium OI matching

Hotspot 2.0 network providers allow 'roaming' between a users home
network and other providers networks, assuming they are part of the
same roaming consortium. The roaming consortium is advertised as an
IE in beacon/probe frames.

In terms of the hotspot config files this is similar to HESSID, where
if the AP advertises the roaming consortium IE, and the config file
matches we do not need to do ANQP in order to connect.

src/hotspot.c

@@ -34,6 +34,7 @@
 #include "src/network.h"
 #include "src/util.h"
 #include "src/hotspot.h"
+#include "src/ie.h"
 
 static struct l_dir_watch *hs20_dir_watch;
 static const char *hs20_dir = DAEMON_STORAGEDIR "/.hotspot";
@@ -43,6 +44,8 @@ struct hs20_config {
 	char *filename;
 	uint8_t hessid[6];
 	char **nai_realms;
+	uint8_t *rc; /* roaming consortium */
+	size_t rc_len;
 };
 
 static bool match_filename(const void *a, const void *b)
@@ -71,27 +74,31 @@ static struct hs20_config *hs20_config_new(struct l_settings *settings,
 	struct hs20_config *config;
 	char *str;
 	char **nai_realms = NULL;
+	const char *rc_str;
 
 	config = l_new(struct hs20_config, 1);
 
-	/* HESSID is an optional field */
+	/* One of HESSID, NAI realms, or Roaming Consortium must be included */
 	str = l_settings_get_string(settings, "Hotspot", "HESSID");
 	if (str) {
 		util_string_to_address(str, config->hessid);
 		l_free(str);
-		goto done;
 	}
 
-	/* NAI realms are required if HESSID is not included */
 	nai_realms = l_settings_get_string_list(settings, "Hotspot",
 						"NAIRealmNames", ',');
-	if (!nai_realms) {
+	if (nai_realms)
+		config->nai_realms = nai_realms;
+
+	rc_str = l_settings_get_value(settings, "Hotspot", "RoamingConsortium");
+	if (rc_str)
+		config->rc = l_util_from_hexstring(rc_str, &config->rc_len);
+
+	if (util_mem_is_zero(config->hessid, 6) && !nai_realms && !config->rc) {
 		l_free(config);
 		return NULL;
 	}
 
-done:
-	config->nai_realms = nai_realms;
 	config->filename = l_strdup(filename);
 
 	return config;
@@ -204,11 +211,39 @@ static bool match_nai_realm(const void *a, const void *b)
 	return false;
 }
 
+static bool match_rc(const void *a, const void *b)
+{
+	const struct hs20_config *config = a;
+	const uint8_t *rc_ie = b;
+	const uint8_t *rc1, *rc2, *rc3;
+	size_t rc1_len, rc2_len, rc3_len;
+
+	if (ie_parse_roaming_consortium_from_data(rc_ie, rc_ie[1] + 2, NULL,
+						&rc1, &rc1_len, &rc2, &rc2_len,
+						&rc3, &rc3_len) < 0)
+		return false;
+
+	/* rc1 is guarenteed to be set if the above returns success */
+	if (rc1_len == config->rc_len && !memcmp(rc1, config->rc, rc1_len))
+		return true;
+
+	if (rc2 && rc2_len == config->rc_len &&
+				!memcmp(rc2, config->rc, rc2_len))
+		return true;
+
+	if (rc3 && rc1_len == config->rc_len &&
+				!memcmp(rc3, config->rc, rc3_len))
+		return true;
+
+	return false;
+}
+
 const char *hs20_find_settings_file(struct network *network)
 {
 	struct hs20_config *config;
 	uint8_t *hessid = network_get_hessid(network);
 	char **nai_realms = network_get_nai_realms(network);
+	const uint8_t *rc_ie = network_get_roaming_consortium(network);
 
 	if (!hessid || util_mem_is_zero(hessid, 6))
 		goto try_nai_realms;
@@ -219,13 +254,21 @@ const char *hs20_find_settings_file(struct network *network)
 
 try_nai_realms:
 	if (!nai_realms)
-		return NULL;
+		goto try_roaming_consortium;
 
 	config = l_queue_find(hs20_settings, match_nai_realm, nai_realms);
-	if (!config)
+	if (config)
+		return config->filename;
+
+try_roaming_consortium:
+	if (!rc_ie)
 		return NULL;
 
+	config = l_queue_find(hs20_settings, match_rc, rc_ie);
+	if (config)
 		return config->filename;
+
+	return NULL;
 }
 
 static int hotspot_init(void)