src/libsystemd-network/sd-icmp6-nd.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright (C) 2014 Intel Corporation. All rights reserved.
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <netinet/icmp6.h>
  21 #include <string.h>
  22 #include <stdbool.h>
  23 #include <netinet/in.h>
  24
  25 #include "socket-util.h"
  26 #include "refcnt.h"
  27 #include "async.h"
  28
  29 #include "dhcp6-internal.h"
  30 #include "sd-icmp6-nd.h"
  31
  32 #define ICMP6_ROUTER_SOLICITATION_INTERVAL      4 * USEC_PER_SEC
  33 #define ICMP6_MAX_ROUTER_SOLICITATIONS          3
  34
  35 enum icmp6_nd_state {
  36         ICMP6_NEIGHBOR_DISCOVERY_IDLE           = 0,
  37         ICMP6_ROUTER_SOLICITATION_SENT          = 10,
  38         ICMP6_ROUTER_ADVERTISMENT_LISTEN        = 11,
  39 };
  40
  41 struct sd_icmp6_nd {
  42         RefCount n_ref;
  43
  44         enum icmp6_nd_state state;
  45         sd_event *event;
  46         int event_priority;
  47         int index;
  48         struct ether_addr mac_addr;
  49         int fd;
  50         sd_event_source *recv;
  51         sd_event_source *timeout;
  52         int nd_sent;
  53         sd_icmp6_nd_callback_t callback;
  54         void *userdata;
  55 };
  56
  57 #define log_icmp6_nd(p, fmt, ...) log_meta(LOG_DEBUG, __FILE__, __LINE__, __func__, "ICMPv6 CLIENT: " fmt, ##__VA_ARGS__)
  58
  59 static void icmp6_nd_notify(sd_icmp6_nd *nd, int event)
  60 {
  61         if (nd->callback)
  62                 nd->callback(nd, event, nd->userdata);
  63 }
  64
  65 int sd_icmp6_nd_set_callback(sd_icmp6_nd *nd, sd_icmp6_nd_callback_t callback,
  66                              void *userdata) {
  67         assert(nd);
  68
  69         nd->callback = callback;
  70         nd->userdata = userdata;
  71
  72         return 0;
  73 }
  74
  75 int sd_icmp6_nd_set_index(sd_icmp6_nd *nd, int interface_index) {
  76         assert(nd);
  77         assert(interface_index >= -1);
  78
  79         nd->index = interface_index;
  80
  81         return 0;
  82 }
  83
  84 int sd_icmp6_nd_set_mac(sd_icmp6_nd *nd, const struct ether_addr *mac_addr) {
  85         assert(nd);
  86
  87         if (mac_addr)
  88                 memcpy(&nd->mac_addr, mac_addr, sizeof(nd->mac_addr));
  89         else
  90                 memset(&nd->mac_addr, 0x00, sizeof(nd->mac_addr));
  91
  92         return 0;
  93
  94 }
  95
  96 int sd_icmp6_nd_attach_event(sd_icmp6_nd *nd, sd_event *event, int priority) {
  97         int r;
  98
  99         assert_return(nd, -EINVAL);
 100         assert_return(!nd->event, -EBUSY);
 101
 102         if (event)
 103                 nd->event = sd_event_ref(event);
 104         else {
 105                 r = sd_event_default(&nd->event);
 106                 if (r < 0)
 107                         return 0;
 108         }
 109
 110         nd->event_priority = priority;
 111
 112         return 0;
 113 }
 114
 115 int sd_icmp6_nd_detach_event(sd_icmp6_nd *nd) {
 116         assert_return(nd, -EINVAL);
 117
 118         nd->event = sd_event_unref(nd->event);
 119
 120         return 0;
 121 }
 122
 123 sd_event *sd_icmp6_nd_get_event(sd_icmp6_nd *nd) {
 124         assert(nd);
 125
 126         return nd->event;
 127 }
 128
 129 sd_icmp6_nd *sd_icmp6_nd_ref(sd_icmp6_nd *nd) {
 130         assert (nd);
 131
 132         assert_se(REFCNT_INC(nd->n_ref) >= 2);
 133
 134         return nd;
 135 }
 136
 137 static int icmp6_nd_init(sd_icmp6_nd *nd) {
 138         assert(nd);
 139
 140         nd->recv = sd_event_source_unref(nd->recv);
 141         nd->fd = asynchronous_close(nd->fd);
 142         nd->timeout = sd_event_source_unref(nd->timeout);
 143
 144         return 0;
 145 }
 146
 147 sd_icmp6_nd *sd_icmp6_nd_unref(sd_icmp6_nd *nd) {
 148         if (nd && REFCNT_DEC(nd->n_ref) <= 0) {
 149
 150                 icmp6_nd_init(nd);
 151                 sd_icmp6_nd_detach_event(nd);
 152
 153                 free(nd);
 154         }
 155
 156         return NULL;
 157 }
 158
 159 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_icmp6_nd*, sd_icmp6_nd_unref);
 160 #define _cleanup_sd_icmp6_nd_free_ _cleanup_(sd_icmp6_nd_unrefp)
 161
 162 int sd_icmp6_nd_new(sd_icmp6_nd **ret) {
 163         _cleanup_sd_icmp6_nd_free_ sd_icmp6_nd *nd = NULL;
 164
 165         assert(ret);
 166
 167         nd = new0(sd_icmp6_nd, 1);
 168         if (!nd)
 169                 return -ENOMEM;
 170
 171         nd->n_ref = REFCNT_INIT;
 172
 173         nd->index = -1;
 174
 175         *ret = nd;
 176         nd = NULL;
 177
 178         return 0;
 179 }
 180
 181 static int icmp6_router_advertisment_recv(sd_event_source *s, int fd,
 182                                           uint32_t revents, void *userdata)
 183 {
 184         sd_icmp6_nd *nd = userdata;
 185         ssize_t len;
 186         struct nd_router_advert ra;
 187         int event = ICMP6_EVENT_ROUTER_ADVERTISMENT_NONE;
 188
 189         assert(s);
 190         assert(nd);
 191         assert(nd->event);
 192
 193         /* only interested in Managed/Other flag */
 194         len = read(fd, &ra, sizeof(ra));
 195         if ((size_t)len < sizeof(ra))
 196                 return 0;
 197
 198         if (ra.nd_ra_type != ND_ROUTER_ADVERT)
 199                 return 0;
 200
 201         if (ra.nd_ra_code != 0)
 202                 return 0;
 203
 204         nd->timeout = sd_event_source_unref(nd->timeout);
 205
 206         nd->state = ICMP6_ROUTER_ADVERTISMENT_LISTEN;
 207
 208         if (ra.nd_ra_flags_reserved & ND_RA_FLAG_OTHER )
 209                 event = ICMP6_EVENT_ROUTER_ADVERTISMENT_OTHER;
 210
 211         if (ra.nd_ra_flags_reserved & ND_RA_FLAG_MANAGED)
 212                 event = ICMP6_EVENT_ROUTER_ADVERTISMENT_MANAGED;
 213
 214         log_icmp6_nd(nd, "Received Router Advertisment flags %s/%s",
 215                      (ra.nd_ra_flags_reserved & ND_RA_FLAG_MANAGED)? "MANAGED":
 216                      "none",
 217                      (ra.nd_ra_flags_reserved & ND_RA_FLAG_OTHER)? "OTHER":
 218                      "none");
 219
 220         icmp6_nd_notify(nd, event);
 221
 222         return 0;
 223 }
 224
 225 static int icmp6_router_solicitation_timeout(sd_event_source *s, uint64_t usec,
 226                                              void *userdata)
 227 {
 228         sd_icmp6_nd *nd = userdata;
 229         uint64_t time_now, next_timeout;
 230         struct ether_addr unset = { };
 231         struct ether_addr *addr = NULL;
 232         int r;
 233
 234         assert(s);
 235         assert(nd);
 236         assert(nd->event);
 237
 238         nd->timeout = sd_event_source_unref(nd->timeout);
 239
 240         if (nd->nd_sent >= ICMP6_MAX_ROUTER_SOLICITATIONS) {
 241                 icmp6_nd_notify(nd, ICMP6_EVENT_ROUTER_ADVERTISMENT_TIMEOUT);
 242                 nd->state = ICMP6_ROUTER_ADVERTISMENT_LISTEN;
 243         } else {
 244                 if (memcmp(&nd->mac_addr, &unset, sizeof(struct ether_addr)))
 245                         addr = &nd->mac_addr;
 246
 247                 r = dhcp_network_icmp6_send_router_solicitation(nd->fd, addr);
 248                 if (r < 0)
 249                         log_icmp6_nd(nd, "Error sending Router Solicitation");
 250                 else {
 251                         nd->state = ICMP6_ROUTER_SOLICITATION_SENT;
 252                         log_icmp6_nd(nd, "Sent Router Solicitation");
 253                 }
 254
 255                 nd->nd_sent++;
 256
 257                 r = sd_event_now(nd->event, CLOCK_MONOTONIC, &time_now);
 258                 if (r < 0) {
 259                         icmp6_nd_notify(nd, r);
 260                         return 0;
 261                 }
 262
 263                 next_timeout = time_now + ICMP6_ROUTER_SOLICITATION_INTERVAL;
 264
 265                 r = sd_event_add_time(nd->event, &nd->timeout, CLOCK_MONOTONIC,
 266                                       next_timeout, 0,
 267                                       icmp6_router_solicitation_timeout, nd);
 268                 if (r < 0) {
 269                         icmp6_nd_notify(nd, r);
 270                         return 0;
 271                 }
 272
 273                 r = sd_event_source_set_priority(nd->timeout,
 274                                                  nd->event_priority);
 275                 if (r < 0) {
 276                         icmp6_nd_notify(nd, r);
 277                         return 0;
 278                 }
 279         }
 280
 281         return 0;
 282 }
 283
 284 int sd_icmp6_router_solicitation_start(sd_icmp6_nd *nd) {
 285         int r;
 286
 287         assert(nd);
 288         assert(nd->event);
 289
 290         if (nd->state != ICMP6_NEIGHBOR_DISCOVERY_IDLE)
 291                 return -EINVAL;
 292
 293         if (nd->index < 1)
 294                 return -EINVAL;
 295
 296         r = dhcp_network_icmp6_bind_router_solicitation(nd->index);
 297         if (r < 0)
 298                 return r;
 299
 300         nd->fd = r;
 301
 302         r = sd_event_add_io(nd->event, &nd->recv, nd->fd, EPOLLIN,
 303                             icmp6_router_advertisment_recv, nd);
 304         if (r < 0)
 305                 goto error;
 306
 307         r = sd_event_source_set_priority(nd->recv, nd->event_priority);
 308         if (r < 0)
 309                 goto error;
 310
 311         r = sd_event_add_time(nd->event, &nd->timeout, CLOCK_MONOTONIC,
 312                               0, 0, icmp6_router_solicitation_timeout, nd);
 313         if (r < 0)
 314                 goto error;
 315
 316         r = sd_event_source_set_priority(nd->timeout, nd->event_priority);
 317
 318 error:
 319         if (r < 0)
 320                 icmp6_nd_init(nd);
 321         else
 322                 log_icmp6_nd(client, "Start Router Solicitation");
 323
 324         return r;
 325 }