link.c

   1 #include <net/if.h>
   2 #include <errno.h>
   3 #include <string.h>
   4 #include <ctype.h>
   5 #include <stdbool.h>
   6
   7 #include <netlink/genl/genl.h>
   8 #include <netlink/genl/family.h>
   9 #include <netlink/genl/ctrl.h>
  10 #include <netlink/msg.h>
  11 #include <netlink/attr.h>
  12
  13 #include "nl80211.h"
  14 #include "iw.h"
  15
  16 struct link_result {
  17         uint8_t bssid[8];
  18         bool link_found;
  19         bool anything_found;
  20 };
  21
  22 static struct link_result lr = { .link_found = false };
  23
  24 static int link_bss_handler(struct nl_msg *msg, void *arg)
  25 {
  26         struct nlattr *tb[NL80211_ATTR_MAX + 1];
  27         struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
  28         struct nlattr *bss[NL80211_BSS_MAX + 1];
  29         static struct nla_policy bss_policy[NL80211_BSS_MAX + 1] = {
  30                 [NL80211_BSS_TSF] = { .type = NLA_U64 },
  31                 [NL80211_BSS_FREQUENCY] = { .type = NLA_U32 },
  32                 [NL80211_BSS_BSSID] = { },
  33                 [NL80211_BSS_BEACON_INTERVAL] = { .type = NLA_U16 },
  34                 [NL80211_BSS_CAPABILITY] = { .type = NLA_U16 },
  35                 [NL80211_BSS_INFORMATION_ELEMENTS] = { },
  36                 [NL80211_BSS_SIGNAL_MBM] = { .type = NLA_U32 },
  37                 [NL80211_BSS_SIGNAL_UNSPEC] = { .type = NLA_U8 },
  38                 [NL80211_BSS_STATUS] = { .type = NLA_U32 },
  39         };
  40         struct link_result *result = arg;
  41         char mac_addr[20], dev[20];
  42
  43         nla_parse(tb, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
  44                   genlmsg_attrlen(gnlh, 0), NULL);
  45
  46         if (!tb[NL80211_ATTR_BSS]) {
  47                 fprintf(stderr, "bss info missing!");
  48                 return NL_SKIP;
  49         }
  50         if (nla_parse_nested(bss, NL80211_BSS_MAX,
  51                              tb[NL80211_ATTR_BSS],
  52                              bss_policy)) {
  53                 fprintf(stderr, "failed to parse nested attributes!");
  54                 return NL_SKIP;
  55         }
  56
  57         if (!bss[NL80211_BSS_BSSID])
  58                 return NL_SKIP;
  59
  60         if (!bss[NL80211_BSS_STATUS])
  61                 return NL_SKIP;
  62
  63         mac_addr_n2a(mac_addr, nla_data(bss[NL80211_BSS_BSSID]));
  64         if_indextoname(nla_get_u32(tb[NL80211_ATTR_IFINDEX]), dev);
  65
  66         switch (nla_get_u32(bss[NL80211_BSS_STATUS])) {
  67         case NL80211_BSS_STATUS_ASSOCIATED:
  68                 printf("Connected to %s (on %s)\n", mac_addr, dev);
  69                 break;
  70         case NL80211_BSS_STATUS_AUTHENTICATED:
  71                 printf("Authenticated with %s (on %s)\n", mac_addr, dev);
  72                 return NL_SKIP;
  73         default:
  74                 return NL_SKIP;
  75         }
  76
  77         result->anything_found = true;
  78
  79         if (bss[NL80211_BSS_INFORMATION_ELEMENTS])
  80                 print_ies(nla_data(bss[NL80211_BSS_INFORMATION_ELEMENTS]),
  81                           nla_len(bss[NL80211_BSS_INFORMATION_ELEMENTS]),
  82                           false, PRINT_LINK);
  83
  84         if (bss[NL80211_BSS_FREQUENCY])
  85                 printf("\tfreq: %d\n",
  86                         nla_get_u32(bss[NL80211_BSS_FREQUENCY]));
  87
  88         if (nla_get_u32(bss[NL80211_BSS_STATUS]) != NL80211_BSS_STATUS_ASSOCIATED)
  89                 return NL_SKIP;
  90
  91         /* only in the assoc case do we want more info from station get */
  92         result->link_found = true;
  93         memcpy(result->bssid, nla_data(bss[NL80211_BSS_BSSID]), 6);
  94         return NL_SKIP;
  95 }
  96
  97 static int handle_scan_for_link(struct nl80211_state *state,
  98                                 struct nl_cb *cb,
  99                                 struct nl_msg *msg,
 100                                 int argc, char **argv)
 101 {
 102         if (argc > 0)
 103                 return 1;
 104
 105         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, link_bss_handler, &lr);
 106         return 0;
 107 }
 108 HIDDEN(link, get_bss, NULL, NL80211_CMD_GET_SCAN, NLM_F_DUMP,
 109         CIB_NETDEV, handle_scan_for_link);
 110
 111 static int print_link_sta(struct nl_msg *msg, void *arg)
 112 {
 113         struct nlattr *tb[NL80211_ATTR_MAX + 1];
 114         struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
 115         struct nlattr *sinfo[NL80211_STA_INFO_MAX + 1];
 116         struct nlattr *rinfo[NL80211_RATE_INFO_MAX + 1];
 117         static struct nla_policy stats_policy[NL80211_STA_INFO_MAX + 1] = {
 118                 [NL80211_STA_INFO_INACTIVE_TIME] = { .type = NLA_U32 },
 119                 [NL80211_STA_INFO_RX_BYTES] = { .type = NLA_U32 },
 120                 [NL80211_STA_INFO_TX_BYTES] = { .type = NLA_U32 },
 121                 [NL80211_STA_INFO_RX_PACKETS] = { .type = NLA_U32 },
 122                 [NL80211_STA_INFO_TX_PACKETS] = { .type = NLA_U32 },
 123                 [NL80211_STA_INFO_SIGNAL] = { .type = NLA_U8 },
 124                 [NL80211_STA_INFO_TX_BITRATE] = { .type = NLA_NESTED },
 125                 [NL80211_STA_INFO_LLID] = { .type = NLA_U16 },
 126                 [NL80211_STA_INFO_PLID] = { .type = NLA_U16 },
 127                 [NL80211_STA_INFO_PLINK_STATE] = { .type = NLA_U8 },
 128         };
 129
 130         static struct nla_policy rate_policy[NL80211_RATE_INFO_MAX + 1] = {
 131                 [NL80211_RATE_INFO_BITRATE] = { .type = NLA_U16 },
 132                 [NL80211_RATE_INFO_MCS] = { .type = NLA_U8 },
 133                 [NL80211_RATE_INFO_40_MHZ_WIDTH] = { .type = NLA_FLAG },
 134                 [NL80211_RATE_INFO_SHORT_GI] = { .type = NLA_FLAG },
 135         };
 136
 137         nla_parse(tb, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
 138                   genlmsg_attrlen(gnlh, 0), NULL);
 139
 140         if (!tb[NL80211_ATTR_STA_INFO]) {
 141                 fprintf(stderr, "sta stats missing!");
 142                 return NL_SKIP;
 143         }
 144         if (nla_parse_nested(sinfo, NL80211_STA_INFO_MAX,
 145                              tb[NL80211_ATTR_STA_INFO],
 146                              stats_policy)) {
 147                 fprintf(stderr, "failed to parse nested attributes!");
 148                 return NL_SKIP;
 149         }
 150
 151         if (sinfo[NL80211_STA_INFO_RX_BYTES] && sinfo[NL80211_STA_INFO_RX_PACKETS])
 152                 printf("\tRX: %u bytes (%u packets)\n",
 153                         nla_get_u32(sinfo[NL80211_STA_INFO_RX_BYTES]),
 154                         nla_get_u32(sinfo[NL80211_STA_INFO_RX_PACKETS]));
 155         if (sinfo[NL80211_STA_INFO_TX_BYTES] && sinfo[NL80211_STA_INFO_TX_PACKETS])
 156                 printf("\tTX: %u bytes (%u packets)\n",
 157                         nla_get_u32(sinfo[NL80211_STA_INFO_TX_BYTES]),
 158                         nla_get_u32(sinfo[NL80211_STA_INFO_TX_PACKETS]));
 159         if (sinfo[NL80211_STA_INFO_SIGNAL])
 160                 printf("\tsignal: %d dBm\n",
 161                         (int8_t)nla_get_u8(sinfo[NL80211_STA_INFO_SIGNAL]));
 162
 163         if (sinfo[NL80211_STA_INFO_TX_BITRATE]) {
 164                 if (nla_parse_nested(rinfo, NL80211_RATE_INFO_MAX,
 165                                      sinfo[NL80211_STA_INFO_TX_BITRATE], rate_policy)) {
 166                         fprintf(stderr, "failed to parse nested rate attributes!");
 167                 } else {
 168                         printf("\ttx bitrate: ");
 169                         if (rinfo[NL80211_RATE_INFO_BITRATE]) {
 170                                 int rate = nla_get_u16(rinfo[NL80211_RATE_INFO_BITRATE]);
 171                                 printf("%d.%d MBit/s", rate / 10, rate % 10);
 172                         }
 173
 174                         if (rinfo[NL80211_RATE_INFO_MCS])
 175                                 printf(" MCS %d", nla_get_u8(rinfo[NL80211_RATE_INFO_MCS]));
 176                         if (rinfo[NL80211_RATE_INFO_40_MHZ_WIDTH])
 177                                 printf(" 40Mhz");
 178                         if (rinfo[NL80211_RATE_INFO_SHORT_GI])
 179                                 printf(" short GI");
 180                         printf("\n");
 181                 }
 182         }
 183
 184         return NL_SKIP;
 185 }
 186
 187 static int handle_link_sta(struct nl80211_state *state,
 188                            struct nl_cb *cb,
 189                            struct nl_msg *msg,
 190                            int argc, char **argv)
 191 {
 192         unsigned char mac_addr[ETH_ALEN];
 193
 194         if (argc < 1)
 195                 return 1;
 196
 197         if (mac_addr_a2n(mac_addr, argv[0])) {
 198                 fprintf(stderr, "invalid mac address\n");
 199                 return 2;
 200         }
 201
 202         argc--;
 203         argv++;
 204
 205         if (argc)
 206                 return 1;
 207
 208         NLA_PUT(msg, NL80211_ATTR_MAC, ETH_ALEN, mac_addr);
 209
 210         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, print_link_sta, NULL);
 211
 212         return 0;
 213  nla_put_failure:
 214         return -ENOBUFS;
 215 }
 216 HIDDEN(link, get_sta, "", NL80211_CMD_GET_STATION, 0,
 217         CIB_NETDEV, handle_link_sta);
 218
 219 static int handle_link(struct nl80211_state *state, struct nl_cb *cb,
 220                        struct nl_msg *msg, int argc, char **argv)
 221 {
 222         char *link_argv[] = {
 223                 NULL,
 224                 "link",
 225                 "get_bss",
 226                 NULL,
 227         };
 228         char *station_argv[] = {
 229                 NULL,
 230                 "link",
 231                 "get_sta",
 232                 NULL,
 233                 NULL,
 234         };
 235         char bssid_buf[3*6];
 236         int err;
 237
 238         link_argv[0] = argv[0];
 239         err = handle_cmd(state, II_NETDEV, 3, link_argv);
 240         if (err)
 241                 return err;
 242
 243         if (!lr.link_found) {
 244                 if (!lr.anything_found)
 245                         printf("Not connected.\n");
 246                 return 0;
 247         }
 248
 249         mac_addr_n2a(bssid_buf, lr.bssid);
 250         bssid_buf[17] = '\0';
 251
 252         station_argv[0] = argv[0];
 253         station_argv[3] = bssid_buf;
 254         return handle_cmd(state, II_NETDEV, 4, station_argv);
 255 }
 256 TOPLEVEL(link, NULL, 0, 0, CIB_NETDEV, handle_link,
 257          "Print information about the current link, if any.");