discover: Recognise renamed network interfaces
[petitboot] / 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 <file/file.h>
15 #include <types/types.h>
16 #include <talloc/talloc.h>
17 #include <waiter/waiter.h>
18 #include <process/process.h>
19 #include <system/system.h>
20
21 #include "network.h"
22 #include "sysinfo.h"
23 #include "platform.h"
24 #include "device-handler.h"
25
26 #define HWADDR_SIZE     6
27 #define PIDFILE_BASE    (LOCAL_STATE_DIR "/petitboot/")
28 #define INITIAL_BUFSIZE 4096
29
30 #define for_each_nlmsg(buf, nlmsg, len) \
31         for (nlmsg = (struct nlmsghdr *)buf; \
32                 NLMSG_OK(nlmsg, len) && nlmsg->nlmsg_type != NLMSG_DONE; \
33                 nlmsg = NLMSG_NEXT(nlmsg, len))
34
35 #define for_each_rta(buf, rta, attrlen) \
36         for (rta = (struct rtattr *)(buf); RTA_OK(rta, attrlen); \
37                         rta = RTA_NEXT(rta, attrlen))
38
39
40 struct interface {
41         int     ifindex;
42         char    name[IFNAMSIZ];
43         uint8_t hwaddr[HWADDR_SIZE];
44
45         enum {
46                 IFSTATE_NEW,
47                 IFSTATE_UP_WAITING_LINK,
48                 IFSTATE_CONFIGURED,
49                 IFSTATE_IGNORED,
50         } state;
51
52         struct list_item list;
53         struct process *udhcpc_process;
54         struct discover_device *dev;
55 };
56
57 struct network {
58         struct list             interfaces;
59         struct device_handler   *handler;
60         struct waiter           *waiter;
61         int                     netlink_sd;
62         void                    *netlink_buf;
63         unsigned int            netlink_buf_size;
64         bool                    manual_config;
65         bool                    dry_run;
66 };
67
68 static const struct interface_config *find_config_by_hwaddr(
69                 uint8_t *hwaddr)
70 {
71         const struct config *config;
72         unsigned int i;
73
74         config = config_get();
75         if (!config)
76                 return NULL;
77
78         for (i = 0; i < config->network.n_interfaces; i++) {
79                 struct interface_config *ifconf = config->network.interfaces[i];
80
81                 if (!memcmp(ifconf->hwaddr, hwaddr, HWADDR_SIZE))
82                         return ifconf;
83         }
84
85         return NULL;
86 }
87
88 static struct interface *find_interface_by_ifindex(struct network *network,
89                 int ifindex)
90 {
91         struct interface *interface;
92
93         list_for_each_entry(&network->interfaces, interface, list)
94                 if (interface->ifindex == ifindex)
95                         return interface;
96
97         return NULL;
98 }
99
100 static struct interface *find_interface_by_name(struct network *network,
101                 const char *name)
102 {
103         struct interface *interface;
104
105         list_for_each_entry(&network->interfaces, interface, list)
106                 if (!strcmp(interface->name, name))
107                         return interface;
108
109         return NULL;
110 }
111
112 uint8_t *find_mac_by_name(void *ctx, struct network *network,
113                 const char *name)
114 {
115         struct interface *interface;
116
117         interface = find_interface_by_name(network, name);
118         if (!interface)
119                 return NULL;
120
121         return talloc_memdup(ctx, &interface->hwaddr,
122                              sizeof(uint8_t) * HWADDR_SIZE);
123 }
124
125 static int network_init_netlink(struct network *network)
126 {
127         struct sockaddr_nl addr;
128         int rc;
129
130         memset(&addr, 0, sizeof(addr));
131         addr.nl_family = AF_NETLINK;
132         addr.nl_groups = RTMGRP_LINK;
133
134         network->netlink_sd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
135         if (network->netlink_sd < 0) {
136                 perror("socket(AF_NETLINK)");
137                 return -1;
138         }
139
140         rc = bind(network->netlink_sd, (struct sockaddr *)&addr, sizeof(addr));
141         if (rc) {
142                 perror("bind(sockaddr_nl)");
143                 close(network->netlink_sd);
144                 return -1;
145         }
146
147         network->netlink_buf_size = INITIAL_BUFSIZE;
148         network->netlink_buf = talloc_array(network, char,
149                                 network->netlink_buf_size);
150
151         return 0;
152 }
153
154 static int network_send_link_query(struct network *network)
155 {
156         int rc;
157         struct {
158                 struct nlmsghdr nlmsg;
159                 struct rtgenmsg rtmsg;
160         } msg;
161
162         memset(&msg, 0, sizeof(msg));
163
164         msg.nlmsg.nlmsg_len = sizeof(msg);
165         msg.nlmsg.nlmsg_type = RTM_GETLINK;
166         msg.nlmsg.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
167         msg.nlmsg.nlmsg_seq = 0;
168         msg.nlmsg.nlmsg_pid = 0;
169         msg.rtmsg.rtgen_family = AF_UNSPEC;
170
171         rc = send(network->netlink_sd, &msg, sizeof(msg), MSG_NOSIGNAL);
172         if (rc != sizeof(msg))
173                 return -1;
174
175         return 0;
176 }
177
178 static char *mac_bytes_to_string(void *ctx, uint8_t *addr, int len)
179 {
180         const int l = strlen("xx:");
181         char *buf;
182         int i;
183
184         if (len <= 0)
185                 return talloc_strdup(ctx, "");
186
187         buf = talloc_array(ctx, char, (len * l) + 1);
188
189         for (i = 0; i < len; i++)
190                 sprintf(buf + (l * i), "%02x:", addr[i]);
191
192         *(buf + (l * len) - 1) = '\0';
193
194         return buf;
195 }
196
197 static void add_interface(struct network *network,
198                 struct interface *interface)
199 {
200         list_add(&network->interfaces, &interface->list);
201         interface->dev = discover_device_create(network->handler,
202                                         interface->name);
203         interface->dev->device->type = DEVICE_TYPE_NETWORK;
204         interface->dev->uuid = mac_bytes_to_string(interface->dev,
205                         interface->hwaddr, sizeof(interface->hwaddr));
206         device_handler_add_device(network->handler, interface->dev);
207 }
208
209 static void remove_interface(struct network *network,
210                 struct interface *interface)
211 {
212         if (interface->dev)
213                 device_handler_remove(network->handler, interface->dev);
214         list_remove(&interface->list);
215         talloc_free(interface);
216 }
217
218 void network_register_device(struct network *network,
219                 struct discover_device *dev)
220 {
221         struct interface *iface;
222
223         iface = find_interface_by_name(network, dev->device->id);
224         if (!iface)
225                 return;
226
227         iface->dev = dev;
228         dev->uuid = mac_bytes_to_string(iface->dev, iface->hwaddr,
229                         sizeof(iface->hwaddr));
230 }
231
232 void network_unregister_device(struct network *network,
233                 struct discover_device *dev)
234 {
235         struct interface *iface;
236
237         iface = find_interface_by_name(network, dev->device->id);
238         if (!iface)
239                 return;
240
241         iface->dev = NULL;
242 }
243
244 static int interface_change(struct interface *interface, bool up)
245 {
246         const char *statestr = up ? "up" : "down";
247         int rc;
248
249         if (!up && interface->udhcpc_process) {
250                 /* we don't care about the callback from here */
251                 interface->udhcpc_process->exit_cb = NULL;
252                 interface->udhcpc_process->data = NULL;
253                 process_stop_async(interface->udhcpc_process);
254                 process_release(interface->udhcpc_process);
255         }
256
257         if (!up) {
258                 rc = process_run_simple(interface, pb_system_apps.ip,
259                                 "address", "flush", "dev", interface->name,
260                                 NULL);
261                 if (rc)
262                         pb_log("failed to flush addresses from interface %s\n",
263                                 interface->name);
264         }
265
266         rc = process_run_simple(interface, pb_system_apps.ip,
267                         "link", "set", interface->name, statestr, NULL);
268         if (rc) {
269                 pb_log("failed to bring interface %s %s\n", interface->name,
270                                 statestr);
271                 return -1;
272         }
273         return 0;
274 }
275
276 static int interface_up(struct interface *interface)
277 {
278         return interface_change(interface, true);
279 }
280
281 static int interface_down(struct interface *interface)
282 {
283         return interface_change(interface, false);
284 }
285
286 static void udhcpc_process_exit(struct process *process)
287 {
288         struct interface *interface = process->data;
289         pb_debug("udhcp client [pid %d] for interface %s exited, rc %d\n",
290                         process->pid, interface->name, process->exit_status);
291         interface->udhcpc_process = NULL;
292         process_release(process);
293 }
294
295 static void configure_interface_dhcp(struct interface *interface)
296 {
297         const struct platform *platform;
298         char pidfile[256], id[10];
299         struct process *process;
300         int rc;
301         const char *argv[] = {
302                 pb_system_apps.udhcpc,
303                 "-R",
304                 "-f",
305                 "-O", "pxeconffile",
306                 "-O", "pxepathprefix",
307                 "-p", pidfile,
308                 "-i", interface->name,
309                 "-x", id, /* [11,12] - dhcp client identifier */
310                 NULL,
311         };
312
313         snprintf(pidfile, sizeof(pidfile), "%s/udhcpc-%s.pid",
314                         PIDFILE_BASE, interface->name);
315
316         platform = platform_get();
317         if (platform && platform->dhcp_arch_id != 0xffff)
318                 snprintf(id, sizeof(id), "0x5d:%04x", platform->dhcp_arch_id);
319         else
320                 argv[11] = NULL;
321
322         process = process_create(interface);
323
324         process->path = pb_system_apps.udhcpc;
325         process->argv = argv;
326         process->exit_cb = udhcpc_process_exit;
327         process->data = interface;
328
329         rc = process_run_async(process);
330
331         if (rc)
332                 process_release(process);
333         else
334                 interface->udhcpc_process = process;
335
336         return;
337 }
338
339 static void configure_interface_static(struct interface *interface,
340                 const struct interface_config *config)
341 {
342         int rc;
343
344         rc = process_run_simple(interface, pb_system_apps.ip,
345                         "address", "add", config->static_config.address,
346                         "dev", interface->name, NULL);
347
348
349         if (rc) {
350                 pb_log("failed to add address %s to interface %s\n",
351                                 config->static_config.address,
352                                 interface->name);
353                 return;
354         }
355
356         /* we need the interface up before we can route through it */
357         rc = interface_up(interface);
358         if (rc)
359                 return;
360
361         if (config->static_config.gateway)
362                 rc = process_run_simple(interface, pb_system_apps.ip,
363                                 "route", "add", "default",
364                                 "via", config->static_config.gateway,
365                                 NULL);
366
367         if (rc) {
368                 pb_log("failed to add default route %s on interface %s\n",
369                                 config->static_config.gateway,
370                                 interface->name);
371         }
372
373         return;
374 }
375
376 static void configure_interface(struct network *network,
377                 struct interface *interface, bool up, bool link)
378 {
379         const struct interface_config *config = NULL;
380
381         if (interface->state == IFSTATE_IGNORED)
382                 return;
383
384         /* old interface? check that we're still up and running */
385         if (interface->state == IFSTATE_CONFIGURED) {
386                 if (!up)
387                         interface->state = IFSTATE_NEW;
388                 else if (!link)
389                         interface->state = IFSTATE_UP_WAITING_LINK;
390                 else
391                         return;
392         }
393
394         /* always up the lookback, no other handling required */
395         if (!strcmp(interface->name, "lo")) {
396                 if (interface->state == IFSTATE_NEW)
397                         interface_up(interface);
398                 interface->state = IFSTATE_CONFIGURED;
399                 return;
400         }
401
402         config = find_config_by_hwaddr(interface->hwaddr);
403         if (config && config->ignore) {
404                 pb_log("network: ignoring interface %s\n", interface->name);
405                 interface->state = IFSTATE_IGNORED;
406                 return;
407         }
408
409         /* if we're in manual config mode, we need an interface configuration */
410         if (network->manual_config && !config) {
411                 interface->state = IFSTATE_IGNORED;
412                 pb_log("network: skipping %s: manual config mode, "
413                                 "but no config for this interface\n",
414                                 interface->name);
415                 return;
416         }
417
418         /* new interface? bring up to the point so we can detect a link */
419         if (interface->state == IFSTATE_NEW) {
420                 if (!up) {
421                         interface_up(interface);
422                         pb_log("network: bringing up interface %s\n",
423                                         interface->name);
424                         return;
425
426                 } else if (!link) {
427                         interface->state = IFSTATE_UP_WAITING_LINK;
428                 }
429         }
430
431         /* no link? wait for a notification */
432         if (interface->state == IFSTATE_UP_WAITING_LINK && !link)
433                 return;
434
435         pb_log("network: configuring interface %s\n", interface->name);
436
437         if (!config || config->method == CONFIG_METHOD_DHCP) {
438                 configure_interface_dhcp(interface);
439
440         } else if (config->method == CONFIG_METHOD_STATIC) {
441                 configure_interface_static(interface, config);
442         }
443 }
444
445 static int network_handle_nlmsg(struct network *network, struct nlmsghdr *nlmsg)
446 {
447         bool have_ifaddr, have_ifname;
448         struct interface *interface;
449         struct ifinfomsg *info;
450         struct rtattr *attr;
451         unsigned int mtu;
452         uint8_t ifaddr[6];
453         char ifname[IFNAMSIZ+1];
454         int attrlen, type;
455
456
457         /* we're only interested in NEWLINK messages */
458         type = nlmsg->nlmsg_type;
459         if (!(type == RTM_NEWLINK || type == RTM_DELLINK))
460                 return 0;
461
462         info = NLMSG_DATA(nlmsg);
463
464         have_ifaddr = have_ifname = false;
465         mtu = 1;
466
467         attrlen = nlmsg->nlmsg_len - sizeof(*info);
468
469         /* extract the interface name and hardware address attributes */
470         for_each_rta(info + 1, attr, attrlen) {
471                 void *data = RTA_DATA(attr);
472
473                 switch (attr->rta_type) {
474                 case IFLA_ADDRESS:
475                         memcpy(ifaddr, data, sizeof(ifaddr));
476                         have_ifaddr = true;
477                         break;
478
479                 case IFLA_IFNAME:
480                         strncpy(ifname, data, IFNAMSIZ);
481                         have_ifname = true;
482                         break;
483
484                 case IFLA_MTU:
485                         mtu = *(unsigned int *)data;
486                         break;
487                 }
488         }
489
490         if (!have_ifaddr || !have_ifname)
491                 return -1;
492
493         if (type == RTM_DELLINK || mtu == 0) {
494                 interface = find_interface_by_ifindex(network, info->ifi_index);
495                 if (!interface)
496                         return 0;
497                 pb_log("network: interface %s removed\n", interface->name);
498                 remove_interface(network, interface);
499                 return 0;
500         }
501
502
503         interface = find_interface_by_ifindex(network, info->ifi_index);
504         if (!interface) {
505                 interface = talloc_zero(network, struct interface);
506                 interface->ifindex = info->ifi_index;
507                 interface->state = IFSTATE_NEW;
508                 memcpy(interface->hwaddr, ifaddr, sizeof(interface->hwaddr));
509                 strncpy(interface->name, ifname, sizeof(interface->name) - 1);
510                 add_interface(network, interface);
511         }
512
513         /* A repeated RTM_NEWLINK can represent an interface name change */
514         if (strncmp(interface->name, ifname, IFNAMSIZ)) {
515                 pb_debug("ifname update: %s -> %s\n", interface->name, ifname);
516                 strncpy(interface->name, ifname, sizeof(interface->name) - 1);
517                 talloc_free(interface->dev->device->id);
518                 interface->dev->device->id =
519                         talloc_strdup(interface->dev->device, ifname);
520         }
521
522         /* notify the sysinfo code about changes to this interface */
523         if (strcmp(interface->name, "lo"))
524                 system_info_register_interface(
525                                 sizeof(interface->hwaddr),
526                                 interface->hwaddr, interface->name,
527                                 info->ifi_flags & IFF_LOWER_UP);
528
529         configure_interface(network, interface,
530                         info->ifi_flags & IFF_UP,
531                         info->ifi_flags & IFF_LOWER_UP);
532
533         return 0;
534 }
535
536 static int network_netlink_process(void *arg)
537 {
538         struct network *network = arg;
539         struct nlmsghdr *nlmsg;
540         struct msghdr msg;
541         struct iovec iov;
542         unsigned int len;
543         int rc, flags;
544
545         memset(&msg, 0, sizeof(msg));
546         msg.msg_iov = &iov;
547         msg.msg_iovlen = 1;
548
549         flags = MSG_PEEK;
550
551 retry:
552         iov.iov_len = network->netlink_buf_size;
553         iov.iov_base = network->netlink_buf;
554
555         rc = recvmsg(network->netlink_sd, &msg, flags);
556
557         if (rc < 0) {
558                 perror("netlink recv header");
559                 return -1;
560         }
561
562         len = rc;
563
564         /* if the netlink message was larger than our buffer, realloc
565          * before reading again */
566         if (len > network->netlink_buf_size || msg.msg_flags & MSG_TRUNC) {
567                 network->netlink_buf_size *= 2;
568                 network->netlink_buf = talloc_realloc(network,
569                                         network->netlink_buf,
570                                         char *,
571                                         network->netlink_buf_size);
572                 goto retry;
573         }
574
575         /* otherwise, we're good to read the entire message without PEEK */
576         if (flags == MSG_PEEK) {
577                 flags = 0;
578                 goto retry;
579         }
580
581         for_each_nlmsg(network->netlink_buf, nlmsg, len)
582                 network_handle_nlmsg(network, nlmsg);
583
584         return 0;
585 }
586
587 static void network_init_dns(struct network *network)
588 {
589         const struct config *config;
590         unsigned int i;
591         int rc, len;
592         bool modified;
593         char *buf;
594
595         if (network->dry_run)
596                 return;
597
598         config = config_get();
599         if (!config || !config->network.n_dns_servers)
600                 return;
601
602         rc = read_file(network, "/etc/resolv.conf", &buf, &len);
603
604         if (rc) {
605                 buf = talloc_strdup(network, "");
606                 len = 0;
607         }
608
609         modified = false;
610
611         for (i = 0; i < config->network.n_dns_servers; i++) {
612                 int dns_conf_len;
613                 char *dns_conf;
614
615                 dns_conf = talloc_asprintf(network, "nameserver %s\n",
616                                 config->network.dns_servers[i]);
617
618                 if (strstr(buf, dns_conf)) {
619                         talloc_free(dns_conf);
620                         continue;
621                 }
622
623                 dns_conf_len = strlen(dns_conf);
624                 buf = talloc_realloc(network, buf, char, len + dns_conf_len + 1);
625                 memcpy(buf + len, dns_conf, dns_conf_len);
626                 len += dns_conf_len;
627                 buf[len] = '\0';
628                 modified = true;
629
630                 talloc_free(dns_conf);
631         }
632
633         if (modified) {
634                 rc = replace_file("/etc/resolv.conf", buf, len);
635                 if (rc)
636                         pb_log("error replacing resolv.conf: %s\n",
637                                         strerror(errno));
638         }
639
640         talloc_free(buf);
641 }
642
643 struct network *network_init(struct device_handler *handler,
644                 struct waitset *waitset, bool dry_run)
645 {
646         struct network *network;
647         int rc;
648
649         network = talloc(handler, struct network);
650         list_init(&network->interfaces);
651         network->handler = handler;
652         network->dry_run = dry_run;
653         network->manual_config = config_get()->network.n_interfaces != 0;
654
655         network_init_dns(network);
656
657         rc = network_init_netlink(network);
658         if (rc)
659                 goto err;
660
661         network->waiter = waiter_register_io(waitset, network->netlink_sd,
662                         WAIT_IN, network_netlink_process, network);
663
664         if (!network->waiter)
665                 goto err;
666
667         rc = network_send_link_query(network);
668         if (rc)
669                 goto err;
670
671         return network;
672
673 err:
674         network_shutdown(network);
675         return NULL;
676 }
677
678 int network_shutdown(struct network *network)
679 {
680         struct interface *interface;
681
682         if (network->waiter)
683                 waiter_remove(network->waiter);
684
685         list_for_each_entry(&network->interfaces, interface, list) {
686                 if (interface->state == IFSTATE_IGNORED)
687                         continue;
688                 if (!strcmp(interface->name, "lo"))
689                         continue;
690                 interface_down(interface);
691         }
692
693         close(network->netlink_sd);
694         talloc_free(network);
695         return 0;
696 }