src/shared/wifi-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <net/ethernet.h>
   4 #include <linux/nl80211.h>
   5
   6 #include "sd-bus.h"
   7
   8 #include "log.h"
   9 #include "netlink-util.h"
  10 #include "wifi-util.h"
  11
  12 int wifi_get_interface(sd_netlink *genl, int ifindex, enum nl80211_iftype *iftype, char **ssid) {
  13         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL, *reply = NULL;
  14         sd_genl_family family;
  15         int r;
  16
  17         assert(genl);
  18         assert(ifindex > 0);
  19
  20         r = sd_genl_message_new(genl, SD_GENL_NL80211, NL80211_CMD_GET_INTERFACE, &m);
  21         if (r < 0)
  22                 return log_debug_errno(r, "Failed to create generic netlink message: %m");
  23
  24         r = sd_netlink_message_append_u32(m, NL80211_ATTR_IFINDEX, ifindex);
  25         if (r < 0)
  26                 return log_debug_errno(r, "Could not append NL80211_ATTR_IFINDEX attribute: %m");
  27
  28         r = sd_netlink_call(genl, m, 0, &reply);
  29         if (r == -ENODEV) {
  30                 /* For obsolete WEXT driver. */
  31                 log_debug_errno(r, "Failed to request information about wifi interface %d. "
  32                                 "The device doesn't seem to have nl80211 interface. Ignoring.",
  33                                 ifindex);
  34                 goto nodata;
  35         }
  36         if (r < 0)
  37                 return log_debug_errno(r, "Failed to request information about wifi interface %d: %m", ifindex);
  38         if (!reply)
  39                 goto nodata;
  40
  41         r = sd_netlink_message_get_errno(reply);
  42         if (r < 0)
  43                 return log_debug_errno(r, "Failed to get information about wifi interface %d: %m", ifindex);
  44
  45         r = sd_genl_message_get_family(genl, reply, &family);
  46         if (r < 0)
  47                 return log_debug_errno(r, "Failed to determine genl family: %m");
  48         if (family != SD_GENL_NL80211) {
  49                 log_debug("Received message of unexpected genl family %u, ignoring.", family);
  50                 goto nodata;
  51         }
  52
  53         if (iftype) {
  54                 uint32_t t;
  55
  56                 r = sd_netlink_message_read_u32(reply, NL80211_ATTR_IFTYPE, &t);
  57                 if (r < 0)
  58                         return log_debug_errno(r, "Failed to get NL80211_ATTR_IFTYPE attribute: %m");
  59                 *iftype = t;
  60         }
  61
  62         if (ssid) {
  63                 r = sd_netlink_message_read_string_strdup(reply, NL80211_ATTR_SSID, ssid);
  64                 if (r == -ENODATA)
  65                         goto nodata;
  66                 if (r < 0)
  67                         return log_debug_errno(r, "Failed to get NL80211_ATTR_SSID attribute: %m");
  68         }
  69
  70         return 1;
  71
  72 nodata:
  73         if (iftype)
  74                 *iftype = 0;
  75         if (ssid)
  76                 *ssid = NULL;
  77         return 0;
  78 }
  79
  80 int wifi_get_station(sd_netlink *genl, int ifindex, struct ether_addr *bssid) {
  81         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL, *reply = NULL;
  82         sd_genl_family family;
  83         int r;
  84
  85         assert(genl);
  86         assert(ifindex > 0);
  87         assert(bssid);
  88
  89         r = sd_genl_message_new(genl, SD_GENL_NL80211, NL80211_CMD_GET_STATION, &m);
  90         if (r < 0)
  91                 return log_debug_errno(r, "Failed to create generic netlink message: %m");
  92
  93         r = sd_netlink_message_set_flags(m, NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP);
  94         if (r < 0)
  95                 return log_debug_errno(r, "Failed to set dump flag: %m");
  96
  97         r = sd_netlink_message_append_u32(m, NL80211_ATTR_IFINDEX, ifindex);
  98         if (r < 0)
  99                 return log_debug_errno(r, "Could not append NL80211_ATTR_IFINDEX attribute: %m");
 100
 101         r = sd_netlink_call(genl, m, 0, &reply);
 102         if (r < 0)
 103                 return log_debug_errno(r, "Failed to request information about wifi station: %m");
 104         if (!reply)
 105                 goto nodata;
 106
 107         r = sd_netlink_message_get_errno(reply);
 108         if (r < 0)
 109                 return log_debug_errno(r, "Failed to get information about wifi station: %m");
 110
 111         r = sd_genl_message_get_family(genl, reply, &family);
 112         if (r < 0)
 113                 return log_debug_errno(r, "Failed to determine genl family: %m");
 114         if (family != SD_GENL_NL80211) {
 115                 log_debug("Received message of unexpected genl family %u, ignoring.", family);
 116                 goto nodata;
 117         }
 118
 119         r = sd_netlink_message_read_ether_addr(reply, NL80211_ATTR_MAC, bssid);
 120         if (r == -ENODATA)
 121                 goto nodata;
 122         if (r < 0)
 123                 return log_debug_errno(r, "Failed to get NL80211_ATTR_MAC attribute: %m");
 124
 125         return 1;
 126
 127 nodata:
 128         *bssid = (struct ether_addr) {};
 129         return 0;
 130 }