src/shared/local-addresses.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   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 static int add_local_gateway(
 146                 struct local_address **list,
 147                 size_t *n_list,
 148                 size_t *n_allocated,
 149                 int af,
 150                 int ifindex,
 151                 uint32_t metric,
 152                 const RouteVia *via) {
 153
 154         assert(list);
 155         assert(n_list);
 156         assert(n_allocated);
 157         assert(via);
 158
 159         if (af != AF_UNSPEC && af != via->family)
 160                 return 0;
 161
 162         if (!GREEDY_REALLOC(*list, *n_allocated, *n_list + 1))
 163                 return -ENOMEM;
 164
 165         (*list)[(*n_list)++] = (struct local_address) {
 166                 .ifindex = ifindex,
 167                 .metric = metric,
 168                 .family = via->family,
 169                 .address = via->address,
 170         };
 171
 172         return 0;
 173 }
 174
 175 int local_gateways(sd_netlink *context, int ifindex, int af, struct local_address **ret) {
 176         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
 177         _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
 178         _cleanup_free_ struct local_address *list = NULL;
 179         size_t n_list = 0, n_allocated = 0;
 180         int r;
 181
 182         assert(ret);
 183
 184         if (context)
 185                 rtnl = sd_netlink_ref(context);
 186         else {
 187                 r = sd_netlink_open(&rtnl);
 188                 if (r < 0)
 189                         return r;
 190         }
 191
 192         r = sd_rtnl_message_new_route(rtnl, &req, RTM_GETROUTE, af, RTPROT_UNSPEC);
 193         if (r < 0)
 194                 return r;
 195
 196         r = sd_netlink_message_request_dump(req, true);
 197         if (r < 0)
 198                 return r;
 199
 200         r = sd_netlink_call(rtnl, req, 0, &reply);
 201         if (r < 0)
 202                 return r;
 203
 204         for (sd_netlink_message *m = reply; m; m = sd_netlink_message_next(m)) {
 205                 _cleanup_ordered_set_free_free_ OrderedSet *multipath_routes = NULL;
 206                 _cleanup_free_ void *rta_multipath = NULL;
 207                 union in_addr_union gateway;
 208                 uint16_t type;
 209                 unsigned char dst_len, src_len, table;
 210                 uint32_t ifi, metric = 0;
 211                 size_t rta_len;
 212                 int family;
 213                 RouteVia via;
 214
 215                 r = sd_netlink_message_get_errno(m);
 216                 if (r < 0)
 217                         return r;
 218
 219                 r = sd_netlink_message_get_type(m, &type);
 220                 if (r < 0)
 221                         return r;
 222                 if (type != RTM_NEWROUTE)
 223                         continue;
 224
 225                 /* We only care for default routes */
 226                 r = sd_rtnl_message_route_get_dst_prefixlen(m, &dst_len);
 227                 if (r < 0)
 228                         return r;
 229                 if (dst_len != 0)
 230                         continue;
 231
 232                 r = sd_rtnl_message_route_get_src_prefixlen(m, &src_len);
 233                 if (r < 0)
 234                         return r;
 235                 if (src_len != 0)
 236                         continue;
 237
 238                 r = sd_rtnl_message_route_get_table(m, &table);
 239                 if (r < 0)
 240                         return r;
 241                 if (table != RT_TABLE_MAIN)
 242                         continue;
 243
 244                 r = sd_netlink_message_read_u32(m, RTA_PRIORITY, &metric);
 245                 if (r < 0 && r != -ENODATA)
 246                         return r;
 247
 248                 r = sd_rtnl_message_route_get_family(m, &family);
 249                 if (r < 0)
 250                         return r;
 251                 if (!IN_SET(family, AF_INET, AF_INET6))
 252                         continue;
 253
 254                 r = sd_netlink_message_read_u32(m, RTA_OIF, &ifi);
 255                 if (r < 0 && r != -ENODATA)
 256                         return r;
 257                 if (r >= 0) {
 258                         if (ifi <= 0)
 259                                 return -EINVAL;
 260                         if (ifindex > 0 && (int) ifi != ifindex)
 261                                 continue;
 262
 263                         r = netlink_message_read_in_addr_union(m, RTA_GATEWAY, family, &gateway);
 264                         if (r < 0 && r != -ENODATA)
 265                                 return r;
 266                         if (r >= 0) {
 267                                 via.family = family;
 268                                 via.address = gateway;
 269                                 r = add_local_gateway(&list, &n_list, &n_allocated, af, ifi, metric, &via);
 270                                 if (r < 0)
 271                                         return r;
 272
 273                                 continue;
 274                         }
 275
 276                         if (family != AF_INET)
 277                                 continue;
 278
 279                         r = sd_netlink_message_read(m, RTA_VIA, sizeof(via), &via);
 280                         if (r < 0 && r != -ENODATA)
 281                                 return r;
 282                         if (r >= 0) {
 283                                 r = add_local_gateway(&list, &n_list, &n_allocated, af, ifi, metric, &via);
 284                                 if (r < 0)
 285                                         return r;
 286
 287                                 continue;
 288                         }
 289                 }
 290
 291                 r = sd_netlink_message_read_data(m, RTA_MULTIPATH, &rta_len, &rta_multipath);
 292                 if (r < 0 && r != -ENODATA)
 293                         return r;
 294                 if (r >= 0) {
 295                         MultipathRoute *mr;
 296
 297                         r = rtattr_read_nexthop(rta_multipath, rta_len, family, &multipath_routes);
 298                         if (r < 0)
 299                                 return r;
 300
 301                         ORDERED_SET_FOREACH(mr, multipath_routes) {
 302                                 if (ifindex > 0 && mr->ifindex != ifindex)
 303                                         continue;
 304
 305                                 r = add_local_gateway(&list, &n_list, &n_allocated, af, ifi, metric, &mr->gateway);
 306                                 if (r < 0)
 307                                         return r;
 308                         }
 309                 }
 310         }
 311
 312         typesafe_qsort(list, n_list, address_compare);
 313
 314         *ret = TAKE_PTR(list);
 315
 316         return (int) n_list;
 317 }