source3/lib/addrchange.c

   1 /*
   2  * Samba Unix/Linux SMB client library
   3  * Copyright (C) Volker Lendecke 2011
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 3 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "includes.h"
  20 #include "lib/addrchange.h"
  21 #include "../lib/util/tevent_ntstatus.h"
  22
  23 #ifdef HAVE_LINUX_RTNETLINK_H
  24
  25 #include "asm/types.h"
  26 #include "linux/netlink.h"
  27 #include "linux/rtnetlink.h"
  28 #include "lib/tsocket/tsocket.h"
  29
  30 struct addrchange_context {
  31         struct tdgram_context *sock;
  32 };
  33
  34 NTSTATUS addrchange_context_create(TALLOC_CTX *mem_ctx,
  35                                    struct addrchange_context **pctx)
  36 {
  37         struct addrchange_context *ctx;
  38         struct sockaddr_nl addr;
  39         NTSTATUS status;
  40         int sock = -1;
  41         int res;
  42         bool ok;
  43
  44         ctx = talloc(mem_ctx, struct addrchange_context);
  45         if (ctx == NULL) {
  46                 return NT_STATUS_NO_MEMORY;
  47         }
  48
  49         sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
  50         if (sock == -1) {
  51                 status = map_nt_error_from_unix(errno);
  52                 goto fail;
  53         }
  54
  55         ok = smb_set_close_on_exec(sock);
  56         if (!ok) {
  57                 status = map_nt_error_from_unix(errno);
  58                 goto fail;
  59         }
  60
  61         res = set_blocking(sock, false);
  62         if (res == -1) {
  63                 status = map_nt_error_from_unix(errno);
  64                 goto fail;
  65         }
  66
  67         /*
  68          * We're interested in address changes
  69          */
  70         ZERO_STRUCT(addr);
  71         addr.nl_family = AF_NETLINK;
  72         addr.nl_groups = RTMGRP_IPV6_IFADDR | RTMGRP_IPV4_IFADDR;
  73
  74         res = bind(sock, (struct sockaddr *)(void *)&addr, sizeof(addr));
  75         if (res == -1) {
  76                 status = map_nt_error_from_unix(errno);
  77                 goto fail;
  78         }
  79
  80         res = tdgram_bsd_existing_socket(ctx, sock, &ctx->sock);
  81         if (res == -1) {
  82                 status = map_nt_error_from_unix(errno);
  83                 goto fail;
  84         }
  85
  86         *pctx = ctx;
  87         return NT_STATUS_OK;
  88 fail:
  89         if (sock != -1) {
  90                 close(sock);
  91         }
  92         TALLOC_FREE(ctx);
  93         return status;
  94 }
  95
  96 struct addrchange_state {
  97         struct tevent_context *ev;
  98         struct addrchange_context *ctx;
  99         uint8_t *buf;
 100         struct tsocket_address *fromaddr;
 101
 102         enum addrchange_type type;
 103         struct sockaddr_storage addr;
 104 };
 105
 106 static void addrchange_done(struct tevent_req *subreq);
 107
 108 struct tevent_req *addrchange_send(TALLOC_CTX *mem_ctx,
 109                                    struct tevent_context *ev,
 110                                    struct addrchange_context *ctx)
 111 {
 112         struct tevent_req *req, *subreq;
 113         struct addrchange_state *state;
 114
 115         req = tevent_req_create(mem_ctx, &state, struct addrchange_state);
 116         if (req == NULL) {
 117                 return NULL;
 118         }
 119         state->ev = ev;
 120         state->ctx = ctx;
 121
 122         subreq = tdgram_recvfrom_send(state, state->ev, state->ctx->sock);
 123         if (tevent_req_nomem(subreq, req)) {
 124                 return tevent_req_post(req, state->ev);
 125         }
 126         tevent_req_set_callback(subreq, addrchange_done, req);
 127         return req;
 128 }
 129
 130 static void addrchange_done(struct tevent_req *subreq)
 131 {
 132         struct tevent_req *req = tevent_req_callback_data(
 133                 subreq, struct tevent_req);
 134         struct addrchange_state *state = tevent_req_data(
 135                 req, struct addrchange_state);
 136         union {
 137                 struct sockaddr sa;
 138                 struct sockaddr_nl nl;
 139                 struct sockaddr_storage ss;
 140         } fromaddr;
 141         struct nlmsghdr *h;
 142         struct ifaddrmsg *ifa;
 143         struct rtattr *rta;
 144         ssize_t received;
 145         int len;
 146         int err;
 147         bool found;
 148
 149         received = tdgram_recvfrom_recv(subreq, &err, state,
 150                                         &state->buf,
 151                                         &state->fromaddr);
 152         TALLOC_FREE(subreq);
 153         if (received == -1) {
 154                 DEBUG(10, ("tdgram_recvfrom_recv returned %s\n", strerror(err)));
 155                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 156                 return;
 157         }
 158         len = tsocket_address_bsd_sockaddr(state->fromaddr,
 159                                            &fromaddr.sa,
 160                                            sizeof(fromaddr));
 161
 162         if ((len != sizeof(fromaddr.nl) ||
 163             fromaddr.sa.sa_family != AF_NETLINK))
 164         {
 165                 DEBUG(10, ("Got message from wrong addr\n"));
 166                 goto retry;
 167         }
 168
 169         if (fromaddr.nl.nl_pid != 0) {
 170                 DEBUG(10, ("Got msg from pid %d, not from the kernel\n",
 171                            (int)fromaddr.nl.nl_pid));
 172                 goto retry;
 173         }
 174
 175         if (received < sizeof(struct nlmsghdr)) {
 176                 DEBUG(10, ("received %d, expected at least %d\n",
 177                            (int)received, (int)sizeof(struct nlmsghdr)));
 178                 goto retry;
 179         }
 180
 181         h = (struct nlmsghdr *)state->buf;
 182         if (h->nlmsg_len < sizeof(struct nlmsghdr)) {
 183                 DEBUG(10, ("nlmsg_len=%d, expected at least %d\n",
 184                            (int)h->nlmsg_len, (int)sizeof(struct nlmsghdr)));
 185                 goto retry;
 186         }
 187         if (h->nlmsg_len > received) {
 188                 DEBUG(10, ("nlmsg_len=%d, expected at most %d\n",
 189                            (int)h->nlmsg_len, (int)received));
 190                 goto retry;
 191         }
 192         switch (h->nlmsg_type) {
 193         case RTM_NEWADDR:
 194                 state->type = ADDRCHANGE_ADD;
 195                 break;
 196         case RTM_DELADDR:
 197                 state->type = ADDRCHANGE_DEL;
 198                 break;
 199         default:
 200                 DEBUG(10, ("Got unexpected type %d - ignoring\n", h->nlmsg_type));
 201                 goto retry;
 202         }
 203
 204         if (h->nlmsg_len < sizeof(struct nlmsghdr)+sizeof(struct ifaddrmsg)) {
 205                 DEBUG(10, ("nlmsg_len=%d, expected at least %d\n",
 206                            (int)h->nlmsg_len,
 207                            (int)(sizeof(struct nlmsghdr)
 208                                  +sizeof(struct ifaddrmsg))));
 209                 tevent_req_nterror(req, NT_STATUS_UNEXPECTED_IO_ERROR);
 210                 return;
 211         }
 212
 213         ifa = (struct ifaddrmsg *)NLMSG_DATA(h);
 214
 215         state->addr.ss_family = ifa->ifa_family;
 216
 217         len = h->nlmsg_len - sizeof(struct nlmsghdr) + sizeof(struct ifaddrmsg);
 218
 219         found = false;
 220
 221         for (rta = IFA_RTA(ifa); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
 222
 223                 if ((rta->rta_type != IFA_LOCAL)
 224                     && (rta->rta_type != IFA_ADDRESS)) {
 225                         continue;
 226                 }
 227
 228                 switch (ifa->ifa_family) {
 229                 case AF_INET: {
 230                         struct sockaddr_in *v4_addr;
 231                         v4_addr = (struct sockaddr_in *)(void *)&state->addr;
 232
 233                         if (RTA_PAYLOAD(rta) != sizeof(uint32_t)) {
 234                                 continue;
 235                         }
 236                         v4_addr->sin_addr.s_addr = *(uint32_t *)RTA_DATA(rta);
 237                         found = true;
 238                         break;
 239                 }
 240                 case AF_INET6: {
 241                         struct sockaddr_in6 *v6_addr;
 242                         v6_addr = (struct sockaddr_in6 *)(void *)&state->addr;
 243
 244                         if (RTA_PAYLOAD(rta) !=
 245                             sizeof(v6_addr->sin6_addr.s6_addr)) {
 246                                 continue;
 247                         }
 248                         memcpy(v6_addr->sin6_addr.s6_addr, RTA_DATA(rta),
 249                                sizeof(v6_addr->sin6_addr.s6_addr));
 250                         found = true;
 251                         break;
 252                 }
 253                 }
 254         }
 255
 256         if (!found) {
 257                 tevent_req_nterror(req, NT_STATUS_INVALID_ADDRESS);
 258                 return;
 259         }
 260
 261         tevent_req_done(req);
 262         return;
 263
 264 retry:
 265         TALLOC_FREE(state->buf);
 266         TALLOC_FREE(state->fromaddr);
 267
 268         subreq = tdgram_recvfrom_send(state, state->ev, state->ctx->sock);
 269         if (tevent_req_nomem(subreq, req)) {
 270                 return;
 271         }
 272         tevent_req_set_callback(subreq, addrchange_done, req);
 273 }
 274
 275 NTSTATUS addrchange_recv(struct tevent_req *req, enum addrchange_type *type,
 276                          struct sockaddr_storage *addr)
 277 {
 278         struct addrchange_state *state = tevent_req_data(
 279                 req, struct addrchange_state);
 280         NTSTATUS status;
 281
 282         if (tevent_req_is_nterror(req, &status)) {
 283                 tevent_req_received(req);
 284                 return status;
 285         }
 286
 287         *type = state->type;
 288         *addr = state->addr;
 289         tevent_req_received(req);
 290         return NT_STATUS_OK;
 291 }
 292
 293 #else
 294
 295 NTSTATUS addrchange_context_create(TALLOC_CTX *mem_ctx,
 296                                    struct addrchange_context **pctx)
 297 {
 298         return NT_STATUS_NOT_SUPPORTED;
 299 }
 300
 301 struct tevent_req *addrchange_send(TALLOC_CTX *mem_ctx,
 302                                    struct tevent_context *ev,
 303                                    struct addrchange_context *ctx)
 304 {
 305         return NULL;
 306 }
 307
 308 NTSTATUS addrchange_recv(struct tevent_req *req, enum addrchange_type *type,
 309                          struct sockaddr_storage *addr)
 310 {
 311         return NT_STATUS_NOT_IMPLEMENTED;
 312 }
 313
 314 #endif