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