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