wiphy: Add utility to check if bss ciphers compatible

Move the BSS's supported ciphers checks from network_bss_select to a new
function in wiphy.c so we can reuse it in device.c.

src/network.c

@@ -483,22 +483,15 @@ struct scan_bss *network_bss_select(struct network *network)
 
 	case SECURITY_PSK:
 	case SECURITY_8021X:
-		/* Pick the first bss that advertises any cipher we support. */
+		/*
+		 * Pick the first bss that advertises ciphers compatible with
+		 * the wiphy.
+		 */
 		for (bss_entry = l_queue_get_entries(bss_list); bss_entry;
 				bss_entry = bss_entry->next) {
 			struct scan_bss *bss = bss_entry->data;
-			struct ie_rsn_info rsn;
 
-			memset(&rsn, 0, sizeof(rsn));
-			scan_bss_get_rsn_info(bss, &rsn);
-
-			if (rsn.mfpr && !wiphy_select_cipher(wiphy,
-					rsn.group_management_cipher))
-				continue;
-
-			if (wiphy_select_cipher(wiphy, rsn.pairwise_ciphers) &&
-					wiphy_select_cipher(wiphy,
-							rsn.group_cipher))
+			if (wiphy_can_connect(wiphy, bss))
 				return bss;
 		}
 

src/wiphy.c

@@ -120,6 +120,30 @@ uint32_t wiphy_get_supported_bands(struct wiphy *wiphy)
 	return scan_freq_set_get_bands(wiphy->supported_freqs);
 }
 
+bool wiphy_can_connect(struct wiphy *wiphy, struct scan_bss *bss)
+{
+	struct ie_rsn_info rsn_info;
+	int r;
+
+	memset(&rsn_info, 0, sizeof(rsn_info));
+	r = scan_bss_get_rsn_info(bss, &rsn_info);
+
+	if (r == 0) {
+		if (!wiphy_select_cipher(wiphy, rsn_info.pairwise_ciphers))
+			return false;
+
+		if (!wiphy_select_cipher(wiphy, rsn_info.group_cipher))
+			return false;
+
+		if (rsn_info.mfpr && !wiphy_select_cipher(wiphy,
+					rsn_info.group_management_cipher))
+			return false;
+	} else if (r != -ENOENT)
+		return false;
+
+	return true;
+}
+
 static void wiphy_print_basic_info(struct wiphy *wiphy)
 {
 	uint32_t bands;

src/wiphy.h

@@ -24,6 +24,7 @@
 #include <stdbool.h>
 
 struct wiphy;
+struct scan_bss;
 
 enum ie_rsn_cipher_suite wiphy_select_cipher(struct wiphy *wiphy,
 							uint16_t mask);
@@ -32,6 +33,7 @@ struct wiphy *wiphy_find(int wiphy_id);
 
 const char *wiphy_get_path(struct wiphy *wiphy);
 uint32_t wiphy_get_supported_bands(struct wiphy *wiphy);
+bool wiphy_can_connect(struct wiphy *wiphy, struct scan_bss *bss);
 
 bool wiphy_init(struct l_genl_family *in);
 bool wiphy_exit(void);