git.ozlabs.org Git - petitboot/blob - discover/network.c

   1
   2 #include <stdbool.h>
   3 #include <stdint.h>
   4 #include <string.h>
   5 #include <stdlib.h>
   6 #include <errno.h>
   7 #include <sys/socket.h>
   8 #include <linux/if.h>
   9 #include <linux/netlink.h>
  10 #include <linux/rtnetlink.h>
  11
  12 #include <log/log.h>
  13 #include <list/list.h>
  14 #include <talloc/talloc.h>
  15 #include <waiter/waiter.h>
  16 #include <pb-config/pb-config.h>
  17 #include <process/process.h>
  18 #include <system/system.h>
  19
  20 #include "file.h"
  21 #include "network.h"
  22
  23 #define HWADDR_SIZE     6
  24 #define PIDFILE_BASE    (LOCAL_STATE_DIR "/petitboot/")
  25
  26 #define for_each_nlmsg(buf, nlmsg, len) \
  27         for (nlmsg = (struct nlmsghdr *)buf; \
  28                 NLMSG_OK(nlmsg, len) && nlmsg->nlmsg_type != NLMSG_DONE; \
  29                 nlmsg = NLMSG_NEXT(nlmsg, len))
  30
  31 #define for_each_rta(buf, rta, attrlen) \
  32         for (rta = (struct rtattr *)(buf); RTA_OK(rta, attrlen); \
  33                         rta = RTA_NEXT(rta, attrlen))
  34
  35
  36 struct interface {
  37         int     ifindex;
  38         char    name[IFNAMSIZ];
  39         uint8_t hwaddr[HWADDR_SIZE];
  40
  41         enum {
  42                 IFSTATE_NEW,
  43                 IFSTATE_UP_WAITING_LINK,
  44                 IFSTATE_CONFIGURED,
  45                 IFSTATE_IGNORED,
  46         } state;
  47
  48         struct list_item list;
  49         struct process *udhcpc_process;
  50 };
  51
  52 struct network {
  53         struct list     interfaces;
  54         struct waiter   *waiter;
  55         int             netlink_sd;
  56         bool            manual_config;
  57         bool            dry_run;
  58 };
  59
  60 static const struct interface_config *find_config_by_hwaddr(
  61                 uint8_t *hwaddr)
  62 {
  63         const struct config *config;
  64         int i;
  65
  66         config = config_get();
  67         if (!config)
  68                 return NULL;
  69
  70         for (i = 0; i < config->network.n_interfaces; i++) {
  71                 struct interface_config *ifconf = config->network.interfaces[i];
  72
  73                 if (!memcmp(ifconf->hwaddr, hwaddr, HWADDR_SIZE))
  74                         return ifconf;
  75         }
  76
  77         return NULL;
  78 }
  79
  80 static struct interface *find_interface_by_ifindex(struct network *network,
  81                 int ifindex)
  82 {
  83         struct interface *interface;
  84
  85         list_for_each_entry(&network->interfaces, interface, list)
  86                 if (interface->ifindex == ifindex)
  87                         return interface;
  88
  89         return NULL;
  90 }
  91
  92 static int network_init_netlink(struct network *network)
  93 {
  94         struct sockaddr_nl addr;
  95         int rc;
  96
  97         memset(&addr, 0, sizeof(addr));
  98         addr.nl_family = AF_NETLINK;
  99         addr.nl_groups = RTMGRP_LINK;
 100
 101         network->netlink_sd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
 102         if (network->netlink_sd < 0) {
 103                 perror("socket(AF_NETLINK)");
 104                 return -1;
 105         }
 106
 107         rc = bind(network->netlink_sd, (struct sockaddr *)&addr, sizeof(addr));
 108         if (rc) {
 109                 perror("bind(sockaddr_nl)");
 110                 close(network->netlink_sd);
 111                 return -1;
 112         }
 113
 114         return 0;
 115 }
 116
 117 static int network_send_link_query(struct network *network)
 118 {
 119         int rc;
 120         struct {
 121                 struct nlmsghdr nlmsg;
 122                 struct rtgenmsg rtmsg;
 123         } msg;
 124
 125         memset(&msg, 0, sizeof(msg));
 126
 127         msg.nlmsg.nlmsg_len = sizeof(msg);
 128         msg.nlmsg.nlmsg_type = RTM_GETLINK;
 129         msg.nlmsg.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
 130         msg.nlmsg.nlmsg_seq = 0;
 131         msg.nlmsg.nlmsg_pid = 0;
 132         msg.rtmsg.rtgen_family = AF_UNSPEC;
 133
 134         rc = send(network->netlink_sd, &msg, sizeof(msg), MSG_NOSIGNAL);
 135         if (rc != sizeof(msg))
 136                 return -1;
 137
 138         return 0;
 139 }
 140
 141 static int interface_change(struct interface *interface, bool up)
 142 {
 143         const char *statestr = up ? "up" : "down";
 144         int rc;
 145
 146         if (!up && interface->udhcpc_process) {
 147                 /* we don't care about the callback from here */
 148                 interface->udhcpc_process->exit_cb = NULL;
 149                 interface->udhcpc_process->data = NULL;
 150                 process_stop_async(interface->udhcpc_process);
 151                 process_release(interface->udhcpc_process);
 152         }
 153
 154         rc = process_run_simple(interface, pb_system_apps.ip,
 155                         "link", "set", interface->name, statestr, NULL);
 156         if (rc) {
 157                 pb_log("failed to bring interface %s %s\n", interface->name,
 158                                 statestr);
 159                 return -1;
 160         }
 161         return 0;
 162 }
 163
 164 static int interface_up(struct interface *interface)
 165 {
 166         return interface_change(interface, true);
 167 }
 168
 169 static int interface_down(struct interface *interface)
 170 {
 171         return interface_change(interface, false);
 172 }
 173
 174 static void udhcpc_process_exit(struct process *process)
 175 {
 176         struct interface *interface = process->data;
 177         pb_log("udhcp client [pid %d] for interface %s exited, rc %d\n",
 178                         process->pid, interface->name, process->exit_status);
 179         interface->udhcpc_process = NULL;
 180         process_release(process);
 181 }
 182
 183 static void configure_interface_dhcp(struct interface *interface)
 184 {
 185         struct process *process;
 186         char pidfile[256];
 187         int rc;
 188         const char *argv[] = {
 189                 pb_system_apps.udhcpc,
 190                 "-R",
 191                 "-n",
 192                 "-p", pidfile,
 193                 "-i", interface->name,
 194                 NULL,
 195         };
 196         snprintf(pidfile, sizeof(pidfile), "%s/udhcpc-%s.pid",
 197                         PIDFILE_BASE, interface->name);
 198
 199         process = process_create(interface);
 200
 201         process->path = pb_system_apps.udhcpc;
 202         process->argv = argv;
 203         process->exit_cb = udhcpc_process_exit;
 204         process->data = interface;
 205
 206         rc = process_run_async(process);
 207
 208         if (rc)
 209                 process_release(process);
 210         else
 211                 interface->udhcpc_process = process;
 212
 213         return;
 214 }
 215
 216 static void configure_interface_static(struct interface *interface,
 217                 const struct interface_config *config)
 218 {
 219         int rc;
 220
 221         rc = process_run_simple(interface, pb_system_apps.ip,
 222                         "address", "add", config->static_config.address,
 223                         "dev", interface->name, NULL);
 224
 225
 226         if (rc) {
 227                 pb_log("failed to add address %s to interface %s\n",
 228                                 config->static_config.address,
 229                                 interface->name);
 230                 return;
 231         }
 232
 233         /* we need the interface up before we can route through it */
 234         rc = interface_up(interface);
 235         if (rc)
 236                 return;
 237
 238         if (config->static_config.gateway)
 239                 rc = process_run_simple(interface, pb_system_apps.ip,
 240                                 "route", "add", "default",
 241                                 "via", config->static_config.gateway,
 242                                 NULL);
 243
 244         if (rc) {
 245                 pb_log("failed to add default route %s on interface %s\n",
 246                                 config->static_config.gateway,
 247                                 interface->name);
 248         }
 249
 250         return;
 251 }
 252
 253 static void configure_interface(struct network *network,
 254                 struct interface *interface, bool up, bool link)
 255 {
 256         const struct interface_config *config = NULL;
 257
 258         if (interface->state == IFSTATE_IGNORED)
 259                 return;
 260
 261         /* old interface? check that we're still up and running */
 262         if (interface->state == IFSTATE_CONFIGURED) {
 263                 if (!up)
 264                         interface->state = IFSTATE_NEW;
 265                 else if (!link)
 266                         interface->state = IFSTATE_UP_WAITING_LINK;
 267                 else
 268                         return;
 269         }
 270
 271         /* always up the lookback, no other handling required */
 272         if (!strcmp(interface->name, "lo")) {
 273                 if (interface->state == IFSTATE_NEW)
 274                         interface_up(interface);
 275                 interface->state = IFSTATE_CONFIGURED;
 276                 return;
 277         }
 278
 279         config = find_config_by_hwaddr(interface->hwaddr);
 280         if (config && config->ignore) {
 281                 pb_log("network: ignoring interface %s\n", interface->name);
 282                 interface->state = IFSTATE_IGNORED;
 283                 return;
 284         }
 285
 286         /* if we're in manual config mode, we need an interface configuration */
 287         if (network->manual_config && !config) {
 288                 interface->state = IFSTATE_IGNORED;
 289                 pb_log("network: skipping %s: manual config mode, "
 290                                 "but no config for this interface\n",
 291                                 interface->name);
 292                 return;
 293         }
 294
 295         /* new interface? bring up to the point so we can detect a link */
 296         if (interface->state == IFSTATE_NEW) {
 297                 if (!up) {
 298                         interface_up(interface);
 299                         pb_log("network: bringing up interface %s\n",
 300                                         interface->name);
 301                         return;
 302
 303                 } else if (!link) {
 304                         interface->state = IFSTATE_UP_WAITING_LINK;
 305                 }
 306         }
 307
 308         /* no link? wait for a notification */
 309         if (interface->state == IFSTATE_UP_WAITING_LINK && !link)
 310                 return;
 311
 312         pb_log("network: configuring interface %s\n", interface->name);
 313
 314         if (!config || config->method == CONFIG_METHOD_DHCP) {
 315                 configure_interface_dhcp(interface);
 316
 317         } else if (config->method == CONFIG_METHOD_STATIC) {
 318                 configure_interface_static(interface, config);
 319         }
 320 }
 321
 322 static int network_handle_nlmsg(struct network *network, struct nlmsghdr *nlmsg)
 323 {
 324         bool have_ifaddr, have_ifname;
 325         struct interface *interface;
 326         struct ifinfomsg *info;
 327         struct rtattr *attr;
 328         uint8_t ifaddr[6];
 329         char ifname[IFNAMSIZ+1];
 330         int attrlen, type;
 331
 332
 333         /* we're only interested in NEWLINK messages */
 334         type = nlmsg->nlmsg_type;
 335         if (!(type == RTM_NEWLINK || type == RTM_DELLINK))
 336                 return 0;
 337
 338         info = NLMSG_DATA(nlmsg);
 339
 340         have_ifaddr = have_ifname = false;
 341
 342         attrlen = nlmsg->nlmsg_len - sizeof(*info);
 343
 344         /* extract the interface name and hardware address attributes */
 345         for_each_rta(info + 1, attr, attrlen) {
 346                 void *data = RTA_DATA(attr);
 347
 348                 switch (attr->rta_type) {
 349                 case IFLA_ADDRESS:
 350                         memcpy(ifaddr, data, sizeof(ifaddr));
 351                         have_ifaddr = true;
 352                         break;
 353
 354                 case IFLA_IFNAME:
 355                         strncpy(ifname, data, IFNAMSIZ);
 356                         have_ifname = true;
 357                         break;
 358                 }
 359         }
 360
 361         if (!have_ifaddr || !have_ifname)
 362                 return -1;
 363
 364         if (type == RTM_DELLINK) {
 365                 interface = find_interface_by_ifindex(network, info->ifi_index);
 366                 if (!interface)
 367                         return 0;
 368                 pb_log("network: interface %s removed\n", interface->name);
 369                 list_remove(&interface->list);
 370                 talloc_free(interface);
 371                 return 0;
 372         }
 373
 374
 375         interface = find_interface_by_ifindex(network, info->ifi_index);
 376         if (!interface) {
 377                 interface = talloc_zero(network, struct interface);
 378                 interface->ifindex = info->ifi_index;
 379                 interface->state = IFSTATE_NEW;
 380                 memcpy(interface->hwaddr, ifaddr, sizeof(interface->hwaddr));
 381                 strncpy(interface->name, ifname, sizeof(interface->name) - 1);
 382         }
 383
 384         configure_interface(network, interface,
 385                         info->ifi_flags & IFF_UP,
 386                         info->ifi_flags & IFF_LOWER_UP);
 387
 388         return 0;
 389 }
 390
 391 static int network_netlink_process(void *arg)
 392 {
 393         struct network *network = arg;
 394         struct nlmsghdr *nlmsg;
 395         unsigned int len;
 396         char buf[4096];
 397         int rc;
 398
 399         rc = recv(network->netlink_sd, buf, sizeof(buf), 0);
 400         if (rc < 0) {
 401                 perror("netlink recv");
 402                 return -1;
 403         }
 404
 405         len = rc;
 406
 407         for_each_nlmsg(buf, nlmsg, len)
 408                 network_handle_nlmsg(network, nlmsg);
 409
 410         return 0;
 411 }
 412
 413 static void network_init_dns(struct network *network)
 414 {
 415         const struct config *config;
 416         int i, rc, len;
 417         bool modified;
 418         char *buf;
 419
 420         if (network->dry_run)
 421                 return;
 422
 423         config = config_get();
 424         if (!config || !config->network.n_dns_servers)
 425                 return;
 426
 427         rc = read_file(network, "/etc/resolv.conf", &buf, &len);
 428
 429         if (rc) {
 430                 buf = talloc_strdup(network, "");
 431                 len = 0;
 432         }
 433
 434         modified = false;
 435
 436         for (i = 0; i < config->network.n_dns_servers; i++) {
 437                 int dns_conf_len;
 438                 char *dns_conf;
 439
 440                 dns_conf = talloc_asprintf(network, "nameserver %s\n",
 441                                 config->network.dns_servers[i]);
 442
 443                 if (strstr(buf, dns_conf)) {
 444                         talloc_free(dns_conf);
 445                         continue;
 446                 }
 447
 448                 dns_conf_len = strlen(dns_conf);
 449                 buf = talloc_realloc(network, buf, char, len + dns_conf_len);
 450                 memcpy(buf + len, dns_conf, dns_conf_len);
 451                 len += dns_conf_len;
 452                 modified = true;
 453
 454                 talloc_free(dns_conf);
 455         }
 456
 457         if (modified) {
 458                 rc = replace_file("/etc/resolv.conf", buf, len);
 459                 if (rc)
 460                         pb_log("error replacing resolv.conf: %s\n",
 461                                         strerror(errno));
 462         }
 463
 464         talloc_free(buf);
 465 }
 466
 467 struct network *network_init(void *ctx, struct waitset *waitset, bool dry_run)
 468 {
 469         struct network *network;
 470         int rc;
 471
 472         network = talloc(ctx, struct network);
 473         list_init(&network->interfaces);
 474         network->manual_config = false;
 475         network->dry_run = dry_run;
 476
 477         network_init_dns(network);
 478
 479         rc = network_init_netlink(network);
 480         if (rc)
 481                 goto err;
 482
 483         network->waiter = waiter_register_io(waitset, network->netlink_sd,
 484                         WAIT_IN, network_netlink_process, network);
 485
 486         if (!network->waiter)
 487                 goto err;
 488
 489         rc = network_send_link_query(network);
 490         if (rc)
 491                 goto err;
 492
 493         return network;
 494
 495 err:
 496         network_shutdown(network);
 497         return NULL;
 498 }
 499
 500
 501 int network_shutdown(struct network *network)
 502 {
 503         struct interface *interface;
 504
 505         if (network->waiter)
 506                 waiter_remove(network->waiter);
 507
 508         list_for_each_entry(&network->interfaces, interface, list)
 509                 interface_down(interface);
 510
 511         close(network->netlink_sd);
 512         talloc_free(network);
 513         return 0;
 514 }