src/shared/local-addresses.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include "sd-netlink.h"
   4
   5 #include "alloc-util.h"
   6 #include "local-addresses.h"
   7 #include "macro.h"
   8 #include "netlink-util.h"
   9 #include "sort-util.h"
  10
  11 static int address_compare(const struct local_address *a, const struct local_address *b) {
  12         int r;
  13
  14         /* Order lowest scope first, IPv4 before IPv6, lowest interface index first */
  15
  16         if (a->family == AF_INET && b->family == AF_INET6)
  17                 return -1;
  18         if (a->family == AF_INET6 && b->family == AF_INET)
  19                 return 1;
  20
  21         r = CMP(a->scope, b->scope);
  22         if (r != 0)
  23                 return r;
  24
  25         r = CMP(a->metric, b->metric);
  26         if (r != 0)
  27                 return r;
  28
  29         r = CMP(a->ifindex, b->ifindex);
  30         if (r != 0)
  31                 return r;
  32
  33         return memcmp(&a->address, &b->address, FAMILY_ADDRESS_SIZE(a->family));
  34 }
  35
  36 int local_addresses(sd_netlink *context, int ifindex, int af, struct local_address **ret) {
  37         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
  38         _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
  39         _cleanup_free_ struct local_address *list = NULL;
  40         size_t n_list = 0, n_allocated = 0;
  41         sd_netlink_message *m;
  42         int r;
  43
  44         assert(ret);
  45
  46         if (context)
  47                 rtnl = sd_netlink_ref(context);
  48         else {
  49                 r = sd_netlink_open(&rtnl);
  50                 if (r < 0)
  51                         return r;
  52         }
  53
  54         r = sd_rtnl_message_new_addr(rtnl, &req, RTM_GETADDR, 0, af);
  55         if (r < 0)
  56                 return r;
  57
  58         r = sd_netlink_call(rtnl, req, 0, &reply);
  59         if (r < 0)
  60                 return r;
  61
  62         for (m = reply; m; m = sd_netlink_message_next(m)) {
  63                 struct local_address *a;
  64                 unsigned char flags;
  65                 uint16_t type;
  66                 int ifi, family;
  67
  68                 r = sd_netlink_message_get_errno(m);
  69                 if (r < 0)
  70                         return r;
  71
  72                 r = sd_netlink_message_get_type(m, &type);
  73                 if (r < 0)
  74                         return r;
  75                 if (type != RTM_NEWADDR)
  76                         continue;
  77
  78                 r = sd_rtnl_message_addr_get_ifindex(m, &ifi);
  79                 if (r < 0)
  80                         return r;
  81                 if (ifindex > 0 && ifi != ifindex)
  82                         continue;
  83
  84                 r = sd_rtnl_message_addr_get_family(m, &family);
  85                 if (r < 0)
  86                         return r;
  87                 if (af != AF_UNSPEC && af != family)
  88                         continue;
  89
  90                 r = sd_rtnl_message_addr_get_flags(m, &flags);
  91                 if (r < 0)
  92                         return r;
  93                 if (flags & IFA_F_DEPRECATED)
  94                         continue;
  95
  96                 if (!GREEDY_REALLOC0(list, n_allocated, n_list+1))
  97                         return -ENOMEM;
  98
  99                 a = list + n_list;
 100
 101                 r = sd_rtnl_message_addr_get_scope(m, &a->scope);
 102                 if (r < 0)
 103                         return r;
 104
 105                 if (ifindex == 0 && IN_SET(a->scope, RT_SCOPE_HOST, RT_SCOPE_NOWHERE))
 106                         continue;
 107
 108                 switch (family) {
 109
 110                 case AF_INET:
 111                         r = sd_netlink_message_read_in_addr(m, IFA_LOCAL, &a->address.in);
 112                         if (r < 0) {
 113                                 r = sd_netlink_message_read_in_addr(m, IFA_ADDRESS, &a->address.in);
 114                                 if (r < 0)
 115                                         continue;
 116                         }
 117                         break;
 118
 119                 case AF_INET6:
 120                         r = sd_netlink_message_read_in6_addr(m, IFA_LOCAL, &a->address.in6);
 121                         if (r < 0) {
 122                                 r = sd_netlink_message_read_in6_addr(m, IFA_ADDRESS, &a->address.in6);
 123                                 if (r < 0)
 124                                         continue;
 125                         }
 126                         break;
 127
 128                 default:
 129                         continue;
 130                 }
 131
 132                 a->ifindex = ifi;
 133                 a->family = family;
 134
 135                 n_list++;
 136         };
 137
 138         typesafe_qsort(list, n_list, address_compare);
 139
 140         *ret = TAKE_PTR(list);
 141
 142         return (int) n_list;
 143 }
 144
 145 int local_gateways(sd_netlink *context, int ifindex, int af, struct local_address **ret) {
 146         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
 147         _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
 148         _cleanup_free_ struct local_address *list = NULL;
 149         sd_netlink_message *m = NULL;
 150         size_t n_list = 0, n_allocated = 0;
 151         int r;
 152
 153         assert(ret);
 154
 155         if (context)
 156                 rtnl = sd_netlink_ref(context);
 157         else {
 158                 r = sd_netlink_open(&rtnl);
 159                 if (r < 0)
 160                         return r;
 161         }
 162
 163         r = sd_rtnl_message_new_route(rtnl, &req, RTM_GETROUTE, af, RTPROT_UNSPEC);
 164         if (r < 0)
 165                 return r;
 166
 167         r = sd_netlink_message_request_dump(req, true);
 168         if (r < 0)
 169                 return r;
 170
 171         r = sd_netlink_call(rtnl, req, 0, &reply);
 172         if (r < 0)
 173                 return r;
 174
 175         for (m = reply; m; m = sd_netlink_message_next(m)) {
 176                 struct local_address *a;
 177                 uint16_t type;
 178                 unsigned char dst_len, src_len, table;
 179                 uint32_t ifi;
 180                 int family;
 181
 182                 r = sd_netlink_message_get_errno(m);
 183                 if (r < 0)
 184                         return r;
 185
 186                 r = sd_netlink_message_get_type(m, &type);
 187                 if (r < 0)
 188                         return r;
 189                 if (type != RTM_NEWROUTE)
 190                         continue;
 191
 192                 /* We only care for default routes */
 193                 r = sd_rtnl_message_route_get_dst_prefixlen(m, &dst_len);
 194                 if (r < 0)
 195                         return r;
 196                 if (dst_len != 0)
 197                         continue;
 198
 199                 r = sd_rtnl_message_route_get_src_prefixlen(m, &src_len);
 200                 if (r < 0)
 201                         return r;
 202                 if (src_len != 0)
 203                         continue;
 204
 205                 r = sd_rtnl_message_route_get_table(m, &table);
 206                 if (r < 0)
 207                         return r;
 208                 if (table != RT_TABLE_MAIN)
 209                         continue;
 210
 211                 r = sd_netlink_message_read_u32(m, RTA_OIF, &ifi);
 212                 if (r == -ENODATA) /* Not all routes have an RTA_OIF attribute (for example nexthop ones) */
 213                         continue;
 214                 if (r < 0)
 215                         return r;
 216                 if (ifindex > 0 && (int) ifi != ifindex)
 217                         continue;
 218
 219                 r = sd_rtnl_message_route_get_family(m, &family);
 220                 if (r < 0)
 221                         return r;
 222                 if (af != AF_UNSPEC && af != family)
 223                         continue;
 224
 225                 if (!GREEDY_REALLOC0(list, n_allocated, n_list + 1))
 226                         return -ENOMEM;
 227
 228                 a = list + n_list;
 229
 230                 switch (family) {
 231                 case AF_INET:
 232                         r = sd_netlink_message_read_in_addr(m, RTA_GATEWAY, &a->address.in);
 233                         if (r < 0)
 234                                 continue;
 235
 236                         break;
 237                 case AF_INET6:
 238                         r = sd_netlink_message_read_in6_addr(m, RTA_GATEWAY, &a->address.in6);
 239                         if (r < 0)
 240                                 continue;
 241
 242                         break;
 243                 default:
 244                         continue;
 245                 }
 246
 247                 sd_netlink_message_read_u32(m, RTA_PRIORITY, &a->metric);
 248
 249                 a->ifindex = ifi;
 250                 a->family = family;
 251
 252                 n_list++;
 253         }
 254
 255         typesafe_qsort(list, n_list, address_compare);
 256
 257         *ret = TAKE_PTR(list);
 258
 259         return (int) n_list;
 260 }