discover: Support DHCP "pathprefix" configuration option
[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         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         struct process *process;
216         char pidfile[256];
217         int rc;
218         const char *argv[] = {
219                 pb_system_apps.udhcpc,
220                 "-R",
221                 "-n",
222                 "-O", "pxeconffile",
223                 "-O", "pxepathprefix",
224                 "-p", pidfile,
225                 "-i", interface->name,
226                 NULL,
227         };
228         snprintf(pidfile, sizeof(pidfile), "%s/udhcpc-%s.pid",
229                         PIDFILE_BASE, interface->name);
230
231         process = process_create(interface);
232
233         process->path = pb_system_apps.udhcpc;
234         process->argv = argv;
235         process->exit_cb = udhcpc_process_exit;
236         process->data = interface;
237
238         rc = process_run_async(process);
239
240         if (rc)
241                 process_release(process);
242         else
243                 interface->udhcpc_process = process;
244
245         return;
246 }
247
248 static void configure_interface_static(struct interface *interface,
249                 const struct interface_config *config)
250 {
251         int rc;
252
253         rc = process_run_simple(interface, pb_system_apps.ip,
254                         "address", "add", config->static_config.address,
255                         "dev", interface->name, NULL);
256
257
258         if (rc) {
259                 pb_log("failed to add address %s to interface %s\n",
260                                 config->static_config.address,
261                                 interface->name);
262                 return;
263         }
264
265         /* we need the interface up before we can route through it */
266         rc = interface_up(interface);
267         if (rc)
268                 return;
269
270         if (config->static_config.gateway)
271                 rc = process_run_simple(interface, pb_system_apps.ip,
272                                 "route", "add", "default",
273                                 "via", config->static_config.gateway,
274                                 NULL);
275
276         if (rc) {
277                 pb_log("failed to add default route %s on interface %s\n",
278                                 config->static_config.gateway,
279                                 interface->name);
280         }
281
282         return;
283 }
284
285 static void configure_interface(struct network *network,
286                 struct interface *interface, bool up, bool link)
287 {
288         const struct interface_config *config = NULL;
289
290         if (interface->state == IFSTATE_IGNORED)
291                 return;
292
293         /* old interface? check that we're still up and running */
294         if (interface->state == IFSTATE_CONFIGURED) {
295                 if (!up)
296                         interface->state = IFSTATE_NEW;
297                 else if (!link)
298                         interface->state = IFSTATE_UP_WAITING_LINK;
299                 else
300                         return;
301         }
302
303         /* always up the lookback, no other handling required */
304         if (!strcmp(interface->name, "lo")) {
305                 if (interface->state == IFSTATE_NEW)
306                         interface_up(interface);
307                 interface->state = IFSTATE_CONFIGURED;
308                 return;
309         }
310
311         config = find_config_by_hwaddr(interface->hwaddr);
312         if (config && config->ignore) {
313                 pb_log("network: ignoring interface %s\n", interface->name);
314                 interface->state = IFSTATE_IGNORED;
315                 return;
316         }
317
318         /* if we're in manual config mode, we need an interface configuration */
319         if (network->manual_config && !config) {
320                 interface->state = IFSTATE_IGNORED;
321                 pb_log("network: skipping %s: manual config mode, "
322                                 "but no config for this interface\n",
323                                 interface->name);
324                 return;
325         }
326
327         /* new interface? bring up to the point so we can detect a link */
328         if (interface->state == IFSTATE_NEW) {
329                 if (!up) {
330                         interface_up(interface);
331                         pb_log("network: bringing up interface %s\n",
332                                         interface->name);
333                         return;
334
335                 } else if (!link) {
336                         interface->state = IFSTATE_UP_WAITING_LINK;
337                 }
338         }
339
340         /* no link? wait for a notification */
341         if (interface->state == IFSTATE_UP_WAITING_LINK && !link)
342                 return;
343
344         pb_log("network: configuring interface %s\n", interface->name);
345
346         if (!config || config->method == CONFIG_METHOD_DHCP) {
347                 configure_interface_dhcp(interface);
348
349         } else if (config->method == CONFIG_METHOD_STATIC) {
350                 configure_interface_static(interface, config);
351         }
352 }
353
354 static int network_handle_nlmsg(struct network *network, struct nlmsghdr *nlmsg)
355 {
356         bool have_ifaddr, have_ifname;
357         struct interface *interface;
358         struct ifinfomsg *info;
359         struct rtattr *attr;
360         unsigned int mtu;
361         uint8_t ifaddr[6];
362         char ifname[IFNAMSIZ+1];
363         int attrlen, type;
364
365
366         /* we're only interested in NEWLINK messages */
367         type = nlmsg->nlmsg_type;
368         if (!(type == RTM_NEWLINK || type == RTM_DELLINK))
369                 return 0;
370
371         info = NLMSG_DATA(nlmsg);
372
373         have_ifaddr = have_ifname = false;
374         mtu = 1;
375
376         attrlen = nlmsg->nlmsg_len - sizeof(*info);
377
378         /* extract the interface name and hardware address attributes */
379         for_each_rta(info + 1, attr, attrlen) {
380                 void *data = RTA_DATA(attr);
381
382                 switch (attr->rta_type) {
383                 case IFLA_ADDRESS:
384                         memcpy(ifaddr, data, sizeof(ifaddr));
385                         have_ifaddr = true;
386                         break;
387
388                 case IFLA_IFNAME:
389                         strncpy(ifname, data, IFNAMSIZ);
390                         have_ifname = true;
391                         break;
392
393                 case IFLA_MTU:
394                         mtu = *(unsigned int *)data;
395                         break;
396                 }
397         }
398
399         if (!have_ifaddr || !have_ifname)
400                 return -1;
401
402         if (type == RTM_DELLINK || mtu == 0) {
403                 interface = find_interface_by_ifindex(network, info->ifi_index);
404                 if (!interface)
405                         return 0;
406                 pb_log("network: interface %s removed\n", interface->name);
407                 remove_interface(network, interface);
408                 return 0;
409         }
410
411
412         interface = find_interface_by_ifindex(network, info->ifi_index);
413         if (!interface) {
414                 interface = talloc_zero(network, struct interface);
415                 interface->ifindex = info->ifi_index;
416                 interface->state = IFSTATE_NEW;
417                 memcpy(interface->hwaddr, ifaddr, sizeof(interface->hwaddr));
418                 strncpy(interface->name, ifname, sizeof(interface->name) - 1);
419                 add_interface(network, interface);
420         }
421
422         /* notify the sysinfo code about changes to this interface */
423         if (strcmp(interface->name, "lo"))
424                 system_info_register_interface(
425                                 sizeof(interface->hwaddr),
426                                 interface->hwaddr, interface->name,
427                                 info->ifi_flags & IFF_LOWER_UP);
428
429         configure_interface(network, interface,
430                         info->ifi_flags & IFF_UP,
431                         info->ifi_flags & IFF_LOWER_UP);
432
433         return 0;
434 }
435
436 static int network_netlink_process(void *arg)
437 {
438         struct network *network = arg;
439         struct nlmsghdr *nlmsg;
440         struct msghdr msg;
441         struct iovec iov;
442         unsigned int len;
443         int rc, flags;
444
445         memset(&msg, 0, sizeof(msg));
446         msg.msg_iov = &iov;
447         msg.msg_iovlen = 1;
448
449         flags = MSG_PEEK;
450
451 retry:
452         iov.iov_len = network->netlink_buf_size;
453         iov.iov_base = network->netlink_buf;
454
455         rc = recvmsg(network->netlink_sd, &msg, flags);
456
457         if (rc < 0) {
458                 perror("netlink recv header");
459                 return -1;
460         }
461
462         len = rc;
463
464         /* if the netlink message was larger than our buffer, realloc
465          * before reading again */
466         if (len > network->netlink_buf_size || msg.msg_flags & MSG_TRUNC) {
467                 network->netlink_buf_size *= 2;
468                 network->netlink_buf = talloc_realloc(network,
469                                         network->netlink_buf,
470                                         char *,
471                                         network->netlink_buf_size);
472                 goto retry;
473         }
474
475         /* otherwise, we're good to read the entire message without PEEK */
476         if (flags == MSG_PEEK) {
477                 flags = 0;
478                 goto retry;
479         }
480
481         for_each_nlmsg(network->netlink_buf, nlmsg, len)
482                 network_handle_nlmsg(network, nlmsg);
483
484         return 0;
485 }
486
487 static void network_init_dns(struct network *network)
488 {
489         const struct config *config;
490         unsigned int i;
491         int rc, len;
492         bool modified;
493         char *buf;
494
495         if (network->dry_run)
496                 return;
497
498         config = config_get();
499         if (!config || !config->network.n_dns_servers)
500                 return;
501
502         rc = read_file(network, "/etc/resolv.conf", &buf, &len);
503
504         if (rc) {
505                 buf = talloc_strdup(network, "");
506                 len = 0;
507         }
508
509         modified = false;
510
511         for (i = 0; i < config->network.n_dns_servers; i++) {
512                 int dns_conf_len;
513                 char *dns_conf;
514
515                 dns_conf = talloc_asprintf(network, "nameserver %s\n",
516                                 config->network.dns_servers[i]);
517
518                 if (strstr(buf, dns_conf)) {
519                         talloc_free(dns_conf);
520                         continue;
521                 }
522
523                 dns_conf_len = strlen(dns_conf);
524                 buf = talloc_realloc(network, buf, char, len + dns_conf_len + 1);
525                 memcpy(buf + len, dns_conf, dns_conf_len);
526                 len += dns_conf_len;
527                 buf[len - 1] = '\0';
528                 modified = true;
529
530                 talloc_free(dns_conf);
531         }
532
533         if (modified) {
534                 rc = replace_file("/etc/resolv.conf", buf, len);
535                 if (rc)
536                         pb_log("error replacing resolv.conf: %s\n",
537                                         strerror(errno));
538         }
539
540         talloc_free(buf);
541 }
542
543 struct network *network_init(struct device_handler *handler,
544                 struct waitset *waitset, bool dry_run)
545 {
546         struct network *network;
547         int rc;
548
549         network = talloc(handler, struct network);
550         list_init(&network->interfaces);
551         network->handler = handler;
552         network->dry_run = dry_run;
553         network->manual_config = config_get()->network.n_interfaces != 0;
554
555         network_init_dns(network);
556
557         rc = network_init_netlink(network);
558         if (rc)
559                 goto err;
560
561         network->waiter = waiter_register_io(waitset, network->netlink_sd,
562                         WAIT_IN, network_netlink_process, network);
563
564         if (!network->waiter)
565                 goto err;
566
567         rc = network_send_link_query(network);
568         if (rc)
569                 goto err;
570
571         return network;
572
573 err:
574         network_shutdown(network);
575         return NULL;
576 }
577
578
579 int network_shutdown(struct network *network)
580 {
581         struct interface *interface;
582
583         if (network->waiter)
584                 waiter_remove(network->waiter);
585
586         list_for_each_entry(&network->interfaces, interface, list) {
587                 if (interface->state == IFSTATE_IGNORED)
588                         continue;
589                 if (!strcmp(interface->name, "lo"))
590                         continue;
591                 interface_down(interface);
592         }
593
594         close(network->netlink_sd);
595         talloc_free(network);
596         return 0;
597 }