1 files changed, 128 insertions, 0 deletions
diff --git a/src/shared/wifi-util.c b/src/shared/wifi-util.c
new file mode 100644
index 0000000..2ac8846
--- /dev/null
+++ b/src/shared/wifi-util.c
@@ -0,0 +1,128 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "log.h"
+#include "wifi-util.h"
+
+int wifi_get_interface(sd_netlink *genl, int ifindex, enum nl80211_iftype *iftype, char **ssid) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL, *reply = NULL;
+        sd_genl_family family;
+        int r;
+
+        assert(genl);
+        assert(ifindex > 0);
+
+        r = sd_genl_message_new(genl, SD_GENL_NL80211, NL80211_CMD_GET_INTERFACE, &m);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to create generic netlink message: %m");
+
+        r = sd_netlink_message_append_u32(m, NL80211_ATTR_IFINDEX, ifindex);
+        if (r < 0)
+                return log_debug_errno(r, "Could not append NL80211_ATTR_IFINDEX attribute: %m");
+
+        r = sd_netlink_call(genl, m, 0, &reply);
+        if (r == -ENODEV) {
+                /* For obsolete WEXT driver. */
+                log_debug_errno(r, "Failed to request information about wifi interface %d. "
+                                "The device doesn't seem to have nl80211 interface. Ignoring.",
+                                ifindex);
+                goto nodata;
+        }
+        if (r < 0)
+                return log_debug_errno(r, "Failed to request information about wifi interface %d: %m", ifindex);
+        if (!reply) {
+                log_debug_errno(r, "No reply received to request for information about wifi interface %d, ignoring.", ifindex);
+                goto nodata;
+        }
+
+        r = sd_netlink_message_get_errno(reply);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to get information about wifi interface %d: %m", ifindex);
+
+        r = sd_genl_message_get_family(genl, reply, &family);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to determine genl family: %m");
+        if (family != SD_GENL_NL80211) {
+                log_debug("Received message of unexpected genl family %u, ignoring.", family);
+                goto nodata;
+        }
+
+        if (iftype) {
+                uint32_t t;
+
+                r = sd_netlink_message_read_u32(reply, NL80211_ATTR_IFTYPE, &t);
+                if (r < 0)
+                        return log_debug_errno(r, "Failed to get NL80211_ATTR_IFTYPE attribute: %m");
+                *iftype = t;
+        }
+
+        if (ssid) {
+                r = sd_netlink_message_read_string_strdup(reply, NL80211_ATTR_SSID, ssid);
+                if (r == -ENODATA)
+                        *ssid = NULL;
+                else if (r < 0)
+                        return log_debug_errno(r, "Failed to get NL80211_ATTR_SSID attribute: %m");
+        }
+
+        return 1;
+
+nodata:
+        if (iftype)
+                *iftype = 0;
+        if (ssid)
+                *ssid = NULL;
+        return 0;
+}
+
+int wifi_get_station(sd_netlink *genl, int ifindex, struct ether_addr *bssid) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL, *reply = NULL;
+        sd_genl_family family;
+        int r;
+
+        assert(genl);
+        assert(ifindex > 0);
+        assert(bssid);
+
+        r = sd_genl_message_new(genl, SD_GENL_NL80211, NL80211_CMD_GET_STATION, &m);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to create generic netlink message: %m");
+
+        r = sd_netlink_message_set_flags(m, NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to set dump flag: %m");
+
+        r = sd_netlink_message_append_u32(m, NL80211_ATTR_IFINDEX, ifindex);
+        if (r < 0)
+                return log_debug_errno(r, "Could not append NL80211_ATTR_IFINDEX attribute: %m");
+
+        r = sd_netlink_call(genl, m, 0, &reply);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to request information about wifi station: %m");
+        if (!reply) {
+                log_debug_errno(r, "No reply received to request for information about wifi station, ignoring.");
+                goto nodata;
+        }
+
+        r = sd_netlink_message_get_errno(reply);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to get information about wifi station: %m");
+
+        r = sd_genl_message_get_family(genl, reply, &family);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to determine genl family: %m");
+        if (family != SD_GENL_NL80211) {
+                log_debug("Received message of unexpected genl family %u, ignoring.", family);
+                goto nodata;
+        }
+
+        r = sd_netlink_message_read_ether_addr(reply, NL80211_ATTR_MAC, bssid);
+        if (r == -ENODATA)
+                goto nodata;
+        if (r < 0)
+                return log_debug_errno(r, "Failed to get NL80211_ATTR_MAC attribute: %m");
+
+        return 1;
+
+nodata:
+        *bssid = (struct ether_addr) {};
+        return 0;
+}