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

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright © 2014 Tom Gundersen
   4 ***/
   5
   6 #include "sd-netlink.h"
   7
   8 #include "alloc-util.h"
   9 #include "local-addresses.h"
  10 #include "macro.h"
  11 #include "netlink-util.h"
  12
  13 static int address_compare(const void *_a, const void *_b) {
  14         const struct local_address *a = _a, *b = _b;
  15
  16         /* Order lowest scope first, IPv4 before IPv6, lowest interface index first */
  17
  18         if (a->family == AF_INET && b->family == AF_INET6)
  19                 return -1;
  20         if (a->family == AF_INET6 && b->family == AF_INET)
  21                 return 1;
  22
  23         if (a->scope < b->scope)
  24                 return -1;
  25         if (a->scope > b->scope)
  26                 return 1;
  27
  28         if (a->metric < b->metric)
  29                 return -1;
  30         if (a->metric > b->metric)
  31                 return 1;
  32
  33         if (a->ifindex < b->ifindex)
  34                 return -1;
  35         if (a->ifindex > b->ifindex)
  36                 return 1;
  37
  38         return memcmp(&a->address, &b->address, FAMILY_ADDRESS_SIZE(a->family));
  39 }
  40
  41 int local_addresses(sd_netlink *context, int ifindex, int af, struct local_address **ret) {
  42         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
  43         _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
  44         _cleanup_free_ struct local_address *list = NULL;
  45         size_t n_list = 0, n_allocated = 0;
  46         sd_netlink_message *m;
  47         int r;
  48
  49         assert(ret);
  50
  51         if (context)
  52                 rtnl = sd_netlink_ref(context);
  53         else {
  54                 r = sd_netlink_open(&rtnl);
  55                 if (r < 0)
  56                         return r;
  57         }
  58
  59         r = sd_rtnl_message_new_addr(rtnl, &req, RTM_GETADDR, 0, af);
  60         if (r < 0)
  61                 return r;
  62
  63         r = sd_netlink_call(rtnl, req, 0, &reply);
  64         if (r < 0)
  65                 return r;
  66
  67         for (m = reply; m; m = sd_netlink_message_next(m)) {
  68                 struct local_address *a;
  69                 unsigned char flags;
  70                 uint16_t type;
  71                 int ifi, family;
  72
  73                 r = sd_netlink_message_get_errno(m);
  74                 if (r < 0)
  75                         return r;
  76
  77                 r = sd_netlink_message_get_type(m, &type);
  78                 if (r < 0)
  79                         return r;
  80                 if (type != RTM_NEWADDR)
  81                         continue;
  82
  83                 r = sd_rtnl_message_addr_get_ifindex(m, &ifi);
  84                 if (r < 0)
  85                         return r;
  86                 if (ifindex > 0 && ifi != ifindex)
  87                         continue;
  88
  89                 r = sd_rtnl_message_addr_get_family(m, &family);
  90                 if (r < 0)
  91                         return r;
  92                 if (af != AF_UNSPEC && af != family)
  93                         continue;
  94
  95                 r = sd_rtnl_message_addr_get_flags(m, &flags);
  96                 if (r < 0)
  97                         return r;
  98                 if (flags & IFA_F_DEPRECATED)
  99                         continue;
 100
 101                 if (!GREEDY_REALLOC0(list, n_allocated, n_list+1))
 102                         return -ENOMEM;
 103
 104                 a = list + n_list;
 105
 106                 r = sd_rtnl_message_addr_get_scope(m, &a->scope);
 107                 if (r < 0)
 108                         return r;
 109
 110                 if (ifindex == 0 && IN_SET(a->scope, RT_SCOPE_HOST, RT_SCOPE_NOWHERE))
 111                         continue;
 112
 113                 switch (family) {
 114
 115                 case AF_INET:
 116                         r = sd_netlink_message_read_in_addr(m, IFA_LOCAL, &a->address.in);
 117                         if (r < 0) {
 118                                 r = sd_netlink_message_read_in_addr(m, IFA_ADDRESS, &a->address.in);
 119                                 if (r < 0)
 120                                         continue;
 121                         }
 122                         break;
 123
 124                 case AF_INET6:
 125                         r = sd_netlink_message_read_in6_addr(m, IFA_LOCAL, &a->address.in6);
 126                         if (r < 0) {
 127                                 r = sd_netlink_message_read_in6_addr(m, IFA_ADDRESS, &a->address.in6);
 128                                 if (r < 0)
 129                                         continue;
 130                         }
 131                         break;
 132
 133                 default:
 134                         continue;
 135                 }
 136
 137                 a->ifindex = ifi;
 138                 a->family = family;
 139
 140                 n_list++;
 141         };
 142
 143         qsort_safe(list, n_list, sizeof(struct local_address), address_compare);
 144
 145         *ret = TAKE_PTR(list);
 146
 147         return (int) n_list;
 148 }
 149
 150 int local_gateways(sd_netlink *context, int ifindex, int af, struct local_address **ret) {
 151         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
 152         _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
 153         _cleanup_free_ struct local_address *list = NULL;
 154         sd_netlink_message *m = NULL;
 155         size_t n_list = 0, n_allocated = 0;
 156         int r;
 157
 158         assert(ret);
 159
 160         if (context)
 161                 rtnl = sd_netlink_ref(context);
 162         else {
 163                 r = sd_netlink_open(&rtnl);
 164                 if (r < 0)
 165                         return r;
 166         }
 167
 168         r = sd_rtnl_message_new_route(rtnl, &req, RTM_GETROUTE, af, RTPROT_UNSPEC);
 169         if (r < 0)
 170                 return r;
 171
 172         r = sd_netlink_message_request_dump(req, true);
 173         if (r < 0)
 174                 return r;
 175
 176         r = sd_netlink_call(rtnl, req, 0, &reply);
 177         if (r < 0)
 178                 return r;
 179
 180         for (m = reply; m; m = sd_netlink_message_next(m)) {
 181                 struct local_address *a;
 182                 uint16_t type;
 183                 unsigned char dst_len, src_len;
 184                 uint32_t ifi;
 185                 int family;
 186
 187                 r = sd_netlink_message_get_errno(m);
 188                 if (r < 0)
 189                         return r;
 190
 191                 r = sd_netlink_message_get_type(m, &type);
 192                 if (r < 0)
 193                         return r;
 194                 if (type != RTM_NEWROUTE)
 195                         continue;
 196
 197                 /* We only care for default routes */
 198                 r = sd_rtnl_message_route_get_dst_prefixlen(m, &dst_len);
 199                 if (r < 0)
 200                         return r;
 201                 if (dst_len != 0)
 202                         continue;
 203
 204                 r = sd_rtnl_message_route_get_src_prefixlen(m, &src_len);
 205                 if (r < 0)
 206                         return r;
 207                 if (src_len != 0)
 208                         continue;
 209
 210                 r = sd_netlink_message_read_u32(m, RTA_OIF, &ifi);
 211                 if (r == -ENODATA) /* Not all routes have an RTA_OIF attribute (for example nexthop ones) */
 212                         continue;
 213                 if (r < 0)
 214                         return r;
 215                 if (ifindex > 0 && (int) ifi != ifindex)
 216                         continue;
 217
 218                 r = sd_rtnl_message_route_get_family(m, &family);
 219                 if (r < 0)
 220                         return r;
 221                 if (af != AF_UNSPEC && af != family)
 222                         continue;
 223
 224                 if (!GREEDY_REALLOC0(list, n_allocated, n_list + 1))
 225                         return -ENOMEM;
 226
 227                 a = list + n_list;
 228
 229                 switch (family) {
 230                 case AF_INET:
 231                         r = sd_netlink_message_read_in_addr(m, RTA_GATEWAY, &a->address.in);
 232                         if (r < 0)
 233                                 continue;
 234
 235                         break;
 236                 case AF_INET6:
 237                         r = sd_netlink_message_read_in6_addr(m, RTA_GATEWAY, &a->address.in6);
 238                         if (r < 0)
 239                                 continue;
 240
 241                         break;
 242                 default:
 243                         continue;
 244                 }
 245
 246                 sd_netlink_message_read_u32(m, RTA_PRIORITY, &a->metric);
 247
 248                 a->ifindex = ifi;
 249                 a->family = family;
 250
 251                 n_list++;
 252         }
 253
 254         if (n_list > 0)
 255                 qsort(list, n_list, sizeof(struct local_address), address_compare);
 256
 257         *ret = TAKE_PTR(list);
 258
 259         return (int) n_list;
 260 }