b9b0c5043f58e3131b0789f1948257051d0f5831
[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 <pb-config/pb-config.h>
18 #include <process/process.h>
19 #include <system/system.h>
20
21 #include "file.h"
22 #include "network.h"
23 #include "sysinfo.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         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         struct process *process;
216         char pidfile[256];
217         int rc;
218         const char *argv[] = {
219                 pb_system_apps.udhcpc,
220                 "-R",
221                 "-n",
222                 "-p", pidfile,
223                 "-i", interface->name,
224                 NULL,
225         };
226         snprintf(pidfile, sizeof(pidfile), "%s/udhcpc-%s.pid",
227                         PIDFILE_BASE, interface->name);
228
229         process = process_create(interface);
230
231         process->path = pb_system_apps.udhcpc;
232         process->argv = argv;
233         process->exit_cb = udhcpc_process_exit;
234         process->data = interface;
235
236         rc = process_run_async(process);
237
238         if (rc)
239                 process_release(process);
240         else
241                 interface->udhcpc_process = process;
242
243         return;
244 }
245
246 static void configure_interface_static(struct interface *interface,
247                 const struct interface_config *config)
248 {
249         int rc;
250
251         rc = process_run_simple(interface, pb_system_apps.ip,
252                         "address", "add", config->static_config.address,
253                         "dev", interface->name, NULL);
254
255
256         if (rc) {
257                 pb_log("failed to add address %s to interface %s\n",
258                                 config->static_config.address,
259                                 interface->name);
260                 return;
261         }
262
263         /* we need the interface up before we can route through it */
264         rc = interface_up(interface);
265         if (rc)
266                 return;
267
268         if (config->static_config.gateway)
269                 rc = process_run_simple(interface, pb_system_apps.ip,
270                                 "route", "add", "default",
271                                 "via", config->static_config.gateway,
272                                 NULL);
273
274         if (rc) {
275                 pb_log("failed to add default route %s on interface %s\n",
276                                 config->static_config.gateway,
277                                 interface->name);
278         }
279
280         return;
281 }
282
283 static void configure_interface(struct network *network,
284                 struct interface *interface, bool up, bool link)
285 {
286         const struct interface_config *config = NULL;
287
288         if (interface->state == IFSTATE_IGNORED)
289                 return;
290
291         /* old interface? check that we're still up and running */
292         if (interface->state == IFSTATE_CONFIGURED) {
293                 if (!up)
294                         interface->state = IFSTATE_NEW;
295                 else if (!link)
296                         interface->state = IFSTATE_UP_WAITING_LINK;
297                 else
298                         return;
299         }
300
301         /* always up the lookback, no other handling required */
302         if (!strcmp(interface->name, "lo")) {
303                 if (interface->state == IFSTATE_NEW)
304                         interface_up(interface);
305                 interface->state = IFSTATE_CONFIGURED;
306                 return;
307         }
308
309         config = find_config_by_hwaddr(interface->hwaddr);
310         if (config && config->ignore) {
311                 pb_log("network: ignoring interface %s\n", interface->name);
312                 interface->state = IFSTATE_IGNORED;
313                 return;
314         }
315
316         /* if we're in manual config mode, we need an interface configuration */
317         if (network->manual_config && !config) {
318                 interface->state = IFSTATE_IGNORED;
319                 pb_log("network: skipping %s: manual config mode, "
320                                 "but no config for this interface\n",
321                                 interface->name);
322                 return;
323         }
324
325         /* new interface? bring up to the point so we can detect a link */
326         if (interface->state == IFSTATE_NEW) {
327                 if (!up) {
328                         interface_up(interface);
329                         pb_log("network: bringing up interface %s\n",
330                                         interface->name);
331                         return;
332
333                 } else if (!link) {
334                         interface->state = IFSTATE_UP_WAITING_LINK;
335                 }
336         }
337
338         /* no link? wait for a notification */
339         if (interface->state == IFSTATE_UP_WAITING_LINK && !link)
340                 return;
341
342         pb_log("network: configuring interface %s\n", interface->name);
343
344         if (!config || config->method == CONFIG_METHOD_DHCP) {
345                 configure_interface_dhcp(interface);
346
347         } else if (config->method == CONFIG_METHOD_STATIC) {
348                 configure_interface_static(interface, config);
349         }
350 }
351
352 static int network_handle_nlmsg(struct network *network, struct nlmsghdr *nlmsg)
353 {
354         bool have_ifaddr, have_ifname;
355         struct interface *interface;
356         struct ifinfomsg *info;
357         struct rtattr *attr;
358         unsigned int mtu;
359         uint8_t ifaddr[6];
360         char ifname[IFNAMSIZ+1];
361         int attrlen, type;
362
363
364         /* we're only interested in NEWLINK messages */
365         type = nlmsg->nlmsg_type;
366         if (!(type == RTM_NEWLINK || type == RTM_DELLINK))
367                 return 0;
368
369         info = NLMSG_DATA(nlmsg);
370
371         have_ifaddr = have_ifname = false;
372
373         attrlen = nlmsg->nlmsg_len - sizeof(*info);
374
375         /* extract the interface name and hardware address attributes */
376         for_each_rta(info + 1, attr, attrlen) {
377                 void *data = RTA_DATA(attr);
378
379                 switch (attr->rta_type) {
380                 case IFLA_ADDRESS:
381                         memcpy(ifaddr, data, sizeof(ifaddr));
382                         have_ifaddr = true;
383                         break;
384
385                 case IFLA_IFNAME:
386                         strncpy(ifname, data, IFNAMSIZ);
387                         have_ifname = true;
388                         break;
389
390                 case IFLA_MTU:
391                         mtu = *(unsigned int *)data;
392                         break;
393                 }
394         }
395
396         if (!have_ifaddr || !have_ifname)
397                 return -1;
398
399         if (type == RTM_DELLINK || mtu == 0) {
400                 interface = find_interface_by_ifindex(network, info->ifi_index);
401                 if (!interface)
402                         return 0;
403                 pb_log("network: interface %s removed\n", interface->name);
404                 remove_interface(network, interface);
405                 return 0;
406         }
407
408
409         interface = find_interface_by_ifindex(network, info->ifi_index);
410         if (!interface) {
411                 interface = talloc_zero(network, struct interface);
412                 interface->ifindex = info->ifi_index;
413                 interface->state = IFSTATE_NEW;
414                 memcpy(interface->hwaddr, ifaddr, sizeof(interface->hwaddr));
415                 strncpy(interface->name, ifname, sizeof(interface->name) - 1);
416                 add_interface(network, interface);
417
418                 /* tell the sysinfo code about this interface */
419                 if (strcmp(interface->name, "lo"))
420                         system_info_register_interface(
421                                         sizeof(interface->hwaddr),
422                                         interface->hwaddr, interface->name);
423         }
424
425         configure_interface(network, interface,
426                         info->ifi_flags & IFF_UP,
427                         info->ifi_flags & IFF_LOWER_UP);
428
429         return 0;
430 }
431
432 static int network_netlink_process(void *arg)
433 {
434         struct network *network = arg;
435         struct nlmsghdr *nlmsg;
436         struct msghdr msg;
437         struct iovec iov;
438         unsigned int len;
439         int rc, flags;
440
441         memset(&msg, 0, sizeof(msg));
442         msg.msg_iov = &iov;
443         msg.msg_iovlen = 1;
444
445         flags = MSG_PEEK;
446
447 retry:
448         iov.iov_len = network->netlink_buf_size;
449         iov.iov_base = network->netlink_buf;
450
451         rc = recvmsg(network->netlink_sd, &msg, flags);
452
453         if (rc < 0) {
454                 perror("netlink recv header");
455                 return -1;
456         }
457
458         len = rc;
459
460         /* if the netlink message was larger than our buffer, realloc
461          * before reading again */
462         if (len > network->netlink_buf_size || msg.msg_flags & MSG_TRUNC) {
463                 network->netlink_buf_size *= 2;
464                 network->netlink_buf = talloc_realloc(network,
465                                         network->netlink_buf,
466                                         char *,
467                                         network->netlink_buf_size);
468                 goto retry;
469         }
470
471         /* otherwise, we're good to read the entire message without PEEK */
472         if (flags == MSG_PEEK) {
473                 flags = 0;
474                 goto retry;
475         }
476
477         for_each_nlmsg(network->netlink_buf, nlmsg, len)
478                 network_handle_nlmsg(network, nlmsg);
479
480         return 0;
481 }
482
483 static void network_init_dns(struct network *network)
484 {
485         const struct config *config;
486         int i, rc, len;
487         bool modified;
488         char *buf;
489
490         if (network->dry_run)
491                 return;
492
493         config = config_get();
494         if (!config || !config->network.n_dns_servers)
495                 return;
496
497         rc = read_file(network, "/etc/resolv.conf", &buf, &len);
498
499         if (rc) {
500                 buf = talloc_strdup(network, "");
501                 len = 0;
502         }
503
504         modified = false;
505
506         for (i = 0; i < config->network.n_dns_servers; i++) {
507                 int dns_conf_len;
508                 char *dns_conf;
509
510                 dns_conf = talloc_asprintf(network, "nameserver %s\n",
511                                 config->network.dns_servers[i]);
512
513                 if (strstr(buf, dns_conf)) {
514                         talloc_free(dns_conf);
515                         continue;
516                 }
517
518                 dns_conf_len = strlen(dns_conf);
519                 buf = talloc_realloc(network, buf, char, len + dns_conf_len + 1);
520                 memcpy(buf + len, dns_conf, dns_conf_len);
521                 len += dns_conf_len;
522                 buf[len - 1] = '\0';
523                 modified = true;
524
525                 talloc_free(dns_conf);
526         }
527
528         if (modified) {
529                 rc = replace_file("/etc/resolv.conf", buf, len);
530                 if (rc)
531                         pb_log("error replacing resolv.conf: %s\n",
532                                         strerror(errno));
533         }
534
535         talloc_free(buf);
536 }
537
538 struct network *network_init(struct device_handler *handler,
539                 struct waitset *waitset, bool dry_run)
540 {
541         struct network *network;
542         int rc;
543
544         network = talloc(handler, struct network);
545         list_init(&network->interfaces);
546         network->handler = handler;
547         network->manual_config = false;
548         network->dry_run = dry_run;
549
550         network_init_dns(network);
551
552         rc = network_init_netlink(network);
553         if (rc)
554                 goto err;
555
556         network->waiter = waiter_register_io(waitset, network->netlink_sd,
557                         WAIT_IN, network_netlink_process, network);
558
559         if (!network->waiter)
560                 goto err;
561
562         rc = network_send_link_query(network);
563         if (rc)
564                 goto err;
565
566         return network;
567
568 err:
569         network_shutdown(network);
570         return NULL;
571 }
572
573
574 int network_shutdown(struct network *network)
575 {
576         struct interface *interface;
577
578         if (network->waiter)
579                 waiter_remove(network->waiter);
580
581         list_for_each_entry(&network->interfaces, interface, list)
582                 interface_down(interface);
583
584         close(network->netlink_sd);
585         talloc_free(network);
586         return 0;
587 }