src/libsystemd/sd-netlink/local-addresses.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright 2008-2011 Lennart Poettering
   4   Copyright 2014 Tom Gundersen
   5 ***/
   6
   7 #include "sd-netlink.h"
   8
   9 #include "alloc-util.h"
  10 #include "local-addresses.h"
  11 #include "macro.h"
  12 #include "netlink-util.h"
  13
  14 static int address_compare(const void *_a, const void *_b) {
  15         const struct local_address *a = _a, *b = _b;
  16
  17         /* Order lowest scope first, IPv4 before IPv6, lowest interface index first */
  18
  19         if (a->family == AF_INET && b->family == AF_INET6)
  20                 return -1;
  21         if (a->family == AF_INET6 && b->family == AF_INET)
  22                 return 1;
  23
  24         if (a->scope < b->scope)
  25                 return -1;
  26         if (a->scope > b->scope)
  27                 return 1;
  28
  29         if (a->metric < b->metric)
  30                 return -1;
  31         if (a->metric > b->metric)
  32                 return 1;
  33
  34         if (a->ifindex < b->ifindex)
  35                 return -1;
  36         if (a->ifindex > b->ifindex)
  37                 return 1;
  38
  39         return memcmp(&a->address, &b->address, FAMILY_ADDRESS_SIZE(a->family));
  40 }
  41
  42 int local_addresses(sd_netlink *context, int ifindex, int af, struct local_address **ret) {
  43         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
  44         _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
  45         _cleanup_free_ struct local_address *list = NULL;
  46         size_t n_list = 0, n_allocated = 0;
  47         sd_netlink_message *m;
  48         int r;
  49
  50         assert(ret);
  51
  52         if (context)
  53                 rtnl = sd_netlink_ref(context);
  54         else {
  55                 r = sd_netlink_open(&rtnl);
  56                 if (r < 0)
  57                         return r;
  58         }
  59
  60         r = sd_rtnl_message_new_addr(rtnl, &req, RTM_GETADDR, 0, af);
  61         if (r < 0)
  62                 return r;
  63
  64         r = sd_netlink_call(rtnl, req, 0, &reply);
  65         if (r < 0)
  66                 return r;
  67
  68         for (m = reply; m; m = sd_netlink_message_next(m)) {
  69                 struct local_address *a;
  70                 unsigned char flags;
  71                 uint16_t type;
  72                 int ifi, family;
  73
  74                 r = sd_netlink_message_get_errno(m);
  75                 if (r < 0)
  76                         return r;
  77
  78                 r = sd_netlink_message_get_type(m, &type);
  79                 if (r < 0)
  80                         return r;
  81                 if (type != RTM_NEWADDR)
  82                         continue;
  83
  84                 r = sd_rtnl_message_addr_get_ifindex(m, &ifi);
  85                 if (r < 0)
  86                         return r;
  87                 if (ifindex > 0 && ifi != ifindex)
  88                         continue;
  89
  90                 r = sd_rtnl_message_addr_get_family(m, &family);
  91                 if (r < 0)
  92                         return r;
  93                 if (af != AF_UNSPEC && af != family)
  94                         continue;
  95
  96                 r = sd_rtnl_message_addr_get_flags(m, &flags);
  97                 if (r < 0)
  98                         return r;
  99                 if (flags & IFA_F_DEPRECATED)
 100                         continue;
 101
 102                 if (!GREEDY_REALLOC0(list, n_allocated, n_list+1))
 103                         return -ENOMEM;
 104
 105                 a = list + n_list;
 106
 107                 r = sd_rtnl_message_addr_get_scope(m, &a->scope);
 108                 if (r < 0)
 109                         return r;
 110
 111                 if (ifindex == 0 && IN_SET(a->scope, RT_SCOPE_HOST, RT_SCOPE_NOWHERE))
 112                         continue;
 113
 114                 switch (family) {
 115
 116                 case AF_INET:
 117                         r = sd_netlink_message_read_in_addr(m, IFA_LOCAL, &a->address.in);
 118                         if (r < 0) {
 119                                 r = sd_netlink_message_read_in_addr(m, IFA_ADDRESS, &a->address.in);
 120                                 if (r < 0)
 121                                         continue;
 122                         }
 123                         break;
 124
 125                 case AF_INET6:
 126                         r = sd_netlink_message_read_in6_addr(m, IFA_LOCAL, &a->address.in6);
 127                         if (r < 0) {
 128                                 r = sd_netlink_message_read_in6_addr(m, IFA_ADDRESS, &a->address.in6);
 129                                 if (r < 0)
 130                                         continue;
 131                         }
 132                         break;
 133
 134                 default:
 135                         continue;
 136                 }
 137
 138                 a->ifindex = ifi;
 139                 a->family = family;
 140
 141                 n_list++;
 142         };
 143
 144         qsort_safe(list, n_list, sizeof(struct local_address), address_compare);
 145
 146         *ret = TAKE_PTR(list);
 147
 148         return (int) n_list;
 149 }
 150
 151 int local_gateways(sd_netlink *context, int ifindex, int af, struct local_address **ret) {
 152         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
 153         _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
 154         _cleanup_free_ struct local_address *list = NULL;
 155         sd_netlink_message *m = NULL;
 156         size_t n_list = 0, n_allocated = 0;
 157         int r;
 158
 159         assert(ret);
 160
 161         if (context)
 162                 rtnl = sd_netlink_ref(context);
 163         else {
 164                 r = sd_netlink_open(&rtnl);
 165                 if (r < 0)
 166                         return r;
 167         }
 168
 169         r = sd_rtnl_message_new_route(rtnl, &req, RTM_GETROUTE, af, RTPROT_UNSPEC);
 170         if (r < 0)
 171                 return r;
 172
 173         r = sd_netlink_message_request_dump(req, true);
 174         if (r < 0)
 175                 return r;
 176
 177         r = sd_netlink_call(rtnl, req, 0, &reply);
 178         if (r < 0)
 179                 return r;
 180
 181         for (m = reply; m; m = sd_netlink_message_next(m)) {
 182                 struct local_address *a;
 183                 uint16_t type;
 184                 unsigned char dst_len, src_len;
 185                 uint32_t ifi;
 186                 int family;
 187
 188                 r = sd_netlink_message_get_errno(m);
 189                 if (r < 0)
 190                         return r;
 191
 192                 r = sd_netlink_message_get_type(m, &type);
 193                 if (r < 0)
 194                         return r;
 195                 if (type != RTM_NEWROUTE)
 196                         continue;
 197
 198                 /* We only care for default routes */
 199                 r = sd_rtnl_message_route_get_dst_prefixlen(m, &dst_len);
 200                 if (r < 0)
 201                         return r;
 202                 if (dst_len != 0)
 203                         continue;
 204
 205                 r = sd_rtnl_message_route_get_src_prefixlen(m, &src_len);
 206                 if (r < 0)
 207                         return r;
 208                 if (src_len != 0)
 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         if (n_list > 0)
 256                 qsort(list, n_list, sizeof(struct local_address), address_compare);
 257
 258         *ret = TAKE_PTR(list);
 259
 260         return (int) n_list;
 261 }