1 /* dhcp.c - DHCP client for dynamic network configuration.
2 *
3 * Copyright 2012 Madhur Verma <mad.flexi@gmail.com>
4 * Copyright 2013 Kyungwan Han <asura321@gmail.com>
5 *
6 * Not in SUSv4.
7 USE_DHCP(NEWTOY(dhcp, "V:H:F:x*r:O*A#<0T#<0t#<0s:p:i:SBRCaovqnbf", TOYFLAG_SBIN|TOYFLAG_ROOTONLY))
8
9 config DHCP
10 bool "dhcp"
11 default n
12 help
13 usage: dhcp [-fbnqvoCRB] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]
14 [-H HOSTNAME] [-V VENDOR] [-x OPT:VAL] [-O OPT]
15
16 Configure network dynamicaly using DHCP.
17
18 -i Interface to use (default eth0)
19 -p Create pidfile
20 -s Run PROG at DHCP events (default /usr/share/dhcp/default.script)
21 -B Request broadcast replies
22 -t Send up to N discover packets
23 -T Pause between packets (default 3 seconds)
24 -A Wait N seconds after failure (default 20)
25 -f Run in foreground
26 -b Background if lease is not obtained
27 -n Exit if lease is not obtained
28 -q Exit after obtaining lease
29 -R Release IP on exit
30 -S Log to syslog too
31 -a Use arping to validate offered address
32 -O Request option OPT from server (cumulative)
33 -o Don't request any options (unless -O is given)
34 -r Request this IP address
35 -x OPT:VAL Include option OPT in sent packets (cumulative)
36 -F Ask server to update DNS mapping for NAME
37 -H Send NAME as client hostname (default none)
38 -V VENDOR Vendor identifier (default 'toybox VERSION')
39 -C Don't send MAC as client identifier
40 -v Verbose
41
42 Signals:
43 USR1 Renew current lease
44 USR2 Release current lease
45
46 */
47
48 #define FOR_dhcp
49 #include "toys.h"
50
51 // TODO: headers not in posix:
52 #include <netinet/ip.h>
53 #include <netinet/udp.h>
54 #include <netpacket/packet.h>
55
56 #include <linux/filter.h> //FIXME: linux specific. fix for other OS ports
57 #include <linux/if_ether.h>
58
59 GLOBALS(
60 char *iface;
61 char *pidfile;
62 char *script;
63 long retries;
64 long timeout;
65 long tryagain;
66 struct arg_list *req_opt;
67 char *req_ip;
68 struct arg_list *pkt_opt;
69 char *fdn_name;
70 char *hostname;
71 char *vendor_cls;
72 )
73
74 #define flag_get(f,v,d) ((toys.optflags & f) ? v : d)
75 #define flag_chk(f) ((toys.optflags & f) ? 1 : 0)
76
77 #define STATE_INIT 0
78 #define STATE_REQUESTING 1
79 #define STATE_BOUND 2
80 #define STATE_RENEWING 3
81 #define STATE_REBINDING 4
82 #define STATE_RENEW_REQUESTED 5
83 #define STATE_RELEASED 6
84
85 #define BOOTP_BROADCAST 0x8000
86 #define DHCP_MAGIC 0x63825363
87
88 #define DHCP_REQUEST 1
89 #define DHCP_REPLY 2
90 #define DHCP_HTYPE_ETHERNET 1
91
92 #define DHCPC_SERVER_PORT 67
93 #define DHCPC_CLIENT_PORT 68
94
95 #define DHCPDISCOVER 1
96 #define DHCPOFFER 2
97 #define DHCPREQUEST 3
98 #define DHCPACK 5
99 #define DHCPNAK 6
100 #define DHCPRELEASE 7
101
102 #define DHCP_OPTION_PADDING 0x00
103 #define DHCP_OPTION_SUBNET_MASK 0x01
104 #define DHCP_OPTION_ROUTER 0x03
105 #define DHCP_OPTION_DNS_SERVER 0x06
106 #define DHCP_OPTION_HOST_NAME 0x0c
107 #define DHCP_OPTION_BROADCAST 0x1c
108 #define DHCP_OPTION_REQ_IPADDR 0x32
109 #define DHCP_OPTION_LEASE_TIME 0x33
110 #define DHCP_OPTION_OVERLOAD 0x34
111 #define DHCP_OPTION_MSG_TYPE 0x35
112 #define DHCP_OPTION_SERVER_ID 0x36
113 #define DHCP_OPTION_REQ_LIST 0x37
114 #define DHCP_OPTION_MAX_SIZE 0x39
115 #define DHCP_OPTION_CLIENTID 0x3D
116 #define DHCP_OPTION_VENDOR 0x3C
117 #define DHCP_OPTION_FQDN 0x51
118 #define DHCP_OPTION_END 0xFF
119
120 #define DHCP_NUM8 (1<<8)
121 #define DHCP_NUM16 (1<<9)
122 #define DHCP_NUM32 DHCP_NUM16 | DHCP_NUM8
123 #define DHCP_STRING (1<<10)
124 #define DHCP_STRLST (1<<11)
125 #define DHCP_IP (1<<12)
126 #define DHCP_IPLIST (1<<13)
127 #define DHCP_IPPLST (1<<14)
128 #define DHCP_STCRTS (1<<15)
129
130 #define LOG_SILENT 0x0
131 #define LOG_CONSOLE 0x1
132 #define LOG_SYSTEM 0x2
133
134 #define MODE_OFF 0
135 #define MODE_RAW 1
136 #define MODE_APP 2
137
138 static void (*dbg)(char *format, ...);
dummy(char * format,...)139 static void dummy(char *format, ...){
140 return;
141 }
142
143 typedef struct dhcpc_result_s {
144 struct in_addr serverid;
145 struct in_addr ipaddr;
146 struct in_addr netmask;
147 struct in_addr dnsaddr;
148 struct in_addr default_router;
149 uint32_t lease_time;
150 } dhcpc_result_t;
151
152 typedef struct __attribute__((packed)) dhcp_msg_s {
153 uint8_t op;
154 uint8_t htype;
155 uint8_t hlen;
156 uint8_t hops;
157 uint32_t xid;
158 uint16_t secs;
159 uint16_t flags;
160 uint32_t ciaddr;
161 uint32_t yiaddr;
162 uint32_t nsiaddr;
163 uint32_t ngiaddr;
164 uint8_t chaddr[16];
165 uint8_t sname[64];
166 uint8_t file[128];
167 uint32_t cookie;
168 uint8_t options[308];
169 } dhcp_msg_t;
170
171 typedef struct __attribute__((packed)) dhcp_raw_s {
172 struct iphdr iph;
173 struct udphdr udph;
174 dhcp_msg_t dhcp;
175 } dhcp_raw_t;
176
177 typedef struct dhcpc_state_s {
178 uint8_t macaddr[6];
179 char *iface;
180 int ifindex;
181 int sockfd;
182 int status;
183 int mode;
184 uint32_t mask;
185 struct in_addr ipaddr;
186 struct in_addr serverid;
187 dhcp_msg_t pdhcp;
188 } dhcpc_state_t;
189
190 typedef struct option_val_s {
191 char *key;
192 uint16_t code;
193 void *val;
194 size_t len;
195 } option_val_t;
196
197 struct fd_pair { int rd; int wr; };
198 static uint32_t xid;
199 static dhcpc_state_t *state;
200 static struct fd_pair sigfd;
201 uint8_t bmacaddr[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
202 int set = 1;
203 uint8_t infomode = LOG_CONSOLE;
204 uint8_t raw_opt[29];
205 int raw_optcount = 0;
206 struct arg_list *x_opt;
207 in_addr_t server = 0;
208
209 static option_val_t *msgopt_list = NULL;
210 static option_val_t options_list[] = {
211 {"lease" , DHCP_NUM32 | 0x33, NULL, 0},
212 {"subnet" , DHCP_IP | 0x01, NULL, 0},
213 {"broadcast" , DHCP_IP | 0x1c, NULL, 0},
214 {"router" , DHCP_IP | 0x03, NULL, 0},
215 {"ipttl" , DHCP_NUM8 | 0x17, NULL, 0},
216 {"mtu" , DHCP_NUM16 | 0x1a, NULL, 0},
217 {"hostname" , DHCP_STRING | 0x0c, NULL, 0},
218 {"domain" , DHCP_STRING | 0x0f, NULL, 0},
219 {"search" , DHCP_STRLST | 0x77, NULL, 0},
220 {"nisdomain" , DHCP_STRING | 0x28, NULL, 0},
221 {"timezone" , DHCP_NUM32 | 0x02, NULL, 0},
222 {"tftp" , DHCP_STRING | 0x42, NULL, 0},
223 {"bootfile" , DHCP_STRING | 0x43, NULL, 0},
224 {"bootsize" , DHCP_NUM16 | 0x0d, NULL, 0},
225 {"rootpath" , DHCP_STRING | 0x11, NULL, 0},
226 {"wpad" , DHCP_STRING | 0xfc, NULL, 0},
227 {"serverid" , DHCP_IP | 0x36, NULL, 0},
228 {"message" , DHCP_STRING | 0x38, NULL, 0},
229 {"vlanid" , DHCP_NUM32 | 0x84, NULL, 0},
230 {"vlanpriority" , DHCP_NUM32 | 0x85, NULL, 0},
231 {"dns" , DHCP_IPLIST | 0x06, NULL, 0},
232 {"wins" , DHCP_IPLIST | 0x2c, NULL, 0},
233 {"nissrv" , DHCP_IPLIST | 0x29, NULL, 0},
234 {"ntpsrv" , DHCP_IPLIST | 0x2a, NULL, 0},
235 {"lprsrv" , DHCP_IPLIST | 0x09, NULL, 0},
236 {"swapsrv" , DHCP_IP | 0x10, NULL, 0},
237 {"routes" , DHCP_STCRTS | 0x21, NULL, 0},
238 {"staticroutes" , DHCP_STCRTS | 0x79, NULL, 0},
239 {"msstaticroutes" , DHCP_STCRTS | 0xf9, NULL, 0},
240 };
241
242 static struct sock_filter filter_instr[] = {
243 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
244 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6),
245 BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6),
246 BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0),
247 BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0), BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
248 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
249 BPF_STMT(BPF_RET|BPF_K, 0xffffffff), BPF_STMT(BPF_RET|BPF_K, 0),
250 };
251
252 static struct sock_fprog filter_prog = {
253 .len = ARRAY_LEN(filter_instr),
254 .filter = (struct sock_filter *) filter_instr,
255 };
256
257 // calculate options size.
dhcp_opt_size(uint8_t * optionptr)258 static int dhcp_opt_size(uint8_t *optionptr)
259 {
260 int i = 0;
261 for(;optionptr[i] != 0xff; i++) if(optionptr[i] != 0x00) i += optionptr[i + 1] + 2 -1;
262 return i;
263 }
264
265 // calculates checksum for dhcp messages.
dhcp_checksum(void * addr,int count)266 static uint16_t dhcp_checksum(void *addr, int count)
267 {
268 int32_t sum = 0;
269 uint16_t tmp = 0, *source = (uint16_t *)addr;
270
271 while (count > 1) {
272 sum += *source++;
273 count -= 2;
274 }
275 if (count > 0) {
276 *(uint8_t*)&tmp = *(uint8_t*)source;
277 sum += tmp;
278 }
279 while (sum >> 16) sum = (sum & 0xffff) + (sum >> 16);
280 return ~sum;
281 }
282
283 // gets information of INTERFACE and updates IFINDEX, MAC and IP
get_interface(char * interface,int * ifindex,uint32_t * oip,uint8_t * mac)284 static int get_interface( char *interface, int *ifindex, uint32_t *oip, uint8_t *mac)
285 {
286 struct ifreq req;
287 struct sockaddr_in *ip;
288 int fd = xsocket(AF_INET, SOCK_RAW, IPPROTO_RAW);
289
290 req.ifr_addr.sa_family = AF_INET;
291 xstrncpy(req.ifr_name, interface, IFNAMSIZ);
292 req.ifr_name[IFNAMSIZ-1] = '\0';
293
294 xioctl(fd, SIOCGIFFLAGS, &req);
295 if (!(req.ifr_flags & IFF_UP)) return -1;
296
297 if (oip) {
298 xioctl(fd, SIOCGIFADDR, &req);
299 ip = (struct sockaddr_in*) &req.ifr_addr;
300 dbg("IP %s\n", inet_ntoa(ip->sin_addr));
301 *oip = ntohl(ip->sin_addr.s_addr);
302 }
303 if (ifindex) {
304 xioctl(fd, SIOCGIFINDEX, &req);
305 dbg("Adapter index %d\n", req.ifr_ifindex);
306 *ifindex = req.ifr_ifindex;
307 }
308 if (mac) {
309 xioctl(fd, SIOCGIFHWADDR, &req);
310 memcpy(mac, req.ifr_hwaddr.sa_data, 6);
311 dbg("MAC %02x:%02x:%02x:%02x:%02x:%02x\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
312 }
313 close(fd);
314 return 0;
315 }
316
317 /*
318 *logs messeges to syslog or console
319 *opening the log is still left with applet.
320 *FIXME: move to more relevent lib. probably libc.c
321 */
infomsg(uint8_t infomode,char * s,...)322 static void infomsg(uint8_t infomode, char *s, ...)
323 {
324 int used;
325 char *msg;
326 va_list p, t;
327
328 if (infomode == LOG_SILENT) return;
329 va_start(p, s);
330 va_copy(t, p);
331 used = vsnprintf(NULL, 0, s, t);
332 used++;
333 va_end(t);
334
335 msg = xmalloc(used);
336 vsnprintf(msg, used, s, p);
337 va_end(p);
338
339 if (infomode & LOG_SYSTEM) syslog(LOG_INFO, "%s", msg);
340 if (infomode & LOG_CONSOLE) printf("%s\n", msg);
341 free(msg);
342 }
343
344 /*
345 * Writes self PID in file PATH
346 * FIXME: libc implementation only writes in /var/run
347 * this is more generic as some implemenation may provide
348 * arguments to write in specific file. as dhcpd does.
349 */
write_pid(char * path)350 static void write_pid(char *path)
351 {
352 int pidfile = open(path, O_CREAT | O_WRONLY | O_TRUNC, 0666);
353 if (pidfile > 0) {
354 char pidbuf[12];
355
356 sprintf(pidbuf, "%u", (unsigned)getpid());
357 write(pidfile, pidbuf, strlen(pidbuf));
358 close(pidfile);
359 }
360 }
361
362 // String STR to UINT32 conversion strored in VAR
strtou32(char * str)363 static long strtou32( char *str)
364 {
365 char *endptr = NULL;
366 int base = 10;
367 errno=0;
368 if (str[0]=='0' && (str[1]=='x' || str[1]=='X')) {
369 base = 16;
370 str+=2;
371 }
372 long ret_val = strtol(str, &endptr, base);
373 if (errno) return -1;
374 else if (endptr && (*endptr!='\0'||endptr == str)) return -1;
375 return ret_val;
376 }
377
378 // IP String STR to binary data.
striptovar(char * str,void * var)379 static int striptovar( char *str, void *var)
380 {
381 in_addr_t addr;
382 if(!str) error_exit("NULL address string.");
383 addr = inet_addr(str);
384 if(addr == -1) error_exit("Wrong address %s.",str );
385 *((uint32_t*)(var)) = (uint32_t)addr;
386 return 0;
387 }
388
389 // String to dhcp option conversion
strtoopt(char * str,uint8_t optonly)390 static int strtoopt( char *str, uint8_t optonly)
391 {
392 char *option, *valstr, *grp, *tp;
393 long optcode = 0, convtmp;
394 uint16_t flag = 0;
395 uint32_t mask, nip, router;
396 int count, size = ARRAY_LEN(options_list);
397
398 if (!*str) return 0;
399 option = strtok((char*)str, ":");
400 if (!option) return -1;
401
402 dbg("-x option : %s ", option);
403 optcode = strtou32(option);
404
405 if (optcode > 0 && optcode < 256) { // raw option
406 for (count = 0; count < size; count++) {
407 if ((options_list[count].code & 0X00FF) == optcode) {
408 flag = (options_list[count].code & 0XFF00);
409 break;
410 }
411 }
412 if (count == size) error_exit("Obsolete OR Unknown Option : %s", option);
413 } else { // string option
414 for (count = 0; count < size; count++) {
415 if (!strcmp(options_list[count].key, option)) {
416 flag = (options_list[count].code & 0XFF00);
417 optcode = (options_list[count].code & 0X00FF);
418 break;
419 }
420 }
421 if (count == size) error_exit("Obsolete OR Unknown Option : %s", option);
422 }
423 if (!flag || !optcode) return -1;
424 if (optonly) return optcode;
425
426 valstr = strtok(NULL, "\n");
427 if (!valstr) error_exit("option %s has no value defined.\n", option);
428 dbg(" value : %-20s \n ", valstr);
429 switch (flag) {
430 case DHCP_NUM32:
431 options_list[count].len = sizeof(uint32_t);
432 options_list[count].val = xmalloc(sizeof(uint32_t));
433 convtmp = strtou32(valstr);
434 if (convtmp < 0) error_exit("Invalid/wrong formated number %s", valstr);
435 convtmp = htonl(convtmp);
436 memcpy(options_list[count].val, &convtmp, sizeof(uint32_t));
437 break;
438 case DHCP_NUM16:
439 options_list[count].len = sizeof(uint16_t);
440 options_list[count].val = xmalloc(sizeof(uint16_t));
441 convtmp = strtou32(valstr);
442 if (convtmp < 0) error_exit("Invalid/malformed number %s", valstr);
443 convtmp = htons(convtmp);
444 memcpy(options_list[count].val, &convtmp, sizeof(uint16_t));
445 break;
446 case DHCP_NUM8:
447 options_list[count].len = sizeof(uint8_t);
448 options_list[count].val = xmalloc(sizeof(uint8_t));
449 convtmp = strtou32(valstr);
450 if (convtmp < 0) error_exit("Invalid/malformed number %s", valstr);
451 memcpy(options_list[count].val, &convtmp, sizeof(uint8_t));
452 break;
453 case DHCP_IP:
454 options_list[count].len = sizeof(uint32_t);
455 options_list[count].val = xmalloc(sizeof(uint32_t));
456 striptovar(valstr, options_list[count].val);
457 break;
458 case DHCP_STRING:
459 options_list[count].len = strlen(valstr);
460 options_list[count].val = strdup(valstr);
461 break;
462 case DHCP_IPLIST:
463 while(valstr){
464 options_list[count].val = xrealloc(options_list[count].val, options_list[count].len + sizeof(uint32_t));
465 striptovar(valstr, ((uint8_t*)options_list[count].val)+options_list[count].len);
466 options_list[count].len += sizeof(uint32_t);
467 valstr = strtok(NULL," \t");
468 }
469 break;
470 case DHCP_STRLST:
471 case DHCP_IPPLST:
472 break;
473 case DHCP_STCRTS:
474 /* Option binary format:
475 * mask [one byte, 0..32]
476 * ip [0..4 bytes depending on mask]
477 * router [4 bytes]
478 * may be repeated
479 * staticroutes 10.0.0.0/8 10.127.0.1, 10.11.12.0/24 10.11.12.1
480 */
481 grp = strtok(valstr, ",");;
482 while(grp){
483 while(*grp == ' ' || *grp == '\t') grp++;
484 tp = strchr(grp, '/');
485 if (!tp) error_exit("malformed static route option");
486 *tp = '\0';
487 mask = strtol(++tp, &tp, 10);
488 if (striptovar(grp, (uint8_t*)&nip) < 0) error_exit("malformed static route option");
489 while(*tp == ' ' || *tp == '\t' || *tp == '-') tp++;
490 if (striptovar(tp, (uint8_t*)&router) < 0) error_exit("malformed static route option");
491 options_list[count].val = xrealloc(options_list[count].val, options_list[count].len + 1 + mask/8 + 4);
492 memcpy(((uint8_t*)options_list[count].val)+options_list[count].len, &mask, 1);
493 options_list[count].len += 1;
494 memcpy(((uint8_t*)options_list[count].val)+options_list[count].len, &nip, mask/8);
495 options_list[count].len += mask/8;
496 memcpy(((uint8_t*)options_list[count].val)+options_list[count].len, &router, 4);
497 options_list[count].len += 4;
498 tp = NULL;
499 grp = strtok(NULL, ",");
500 }
501 break;
502 }
503 return 0;
504 }
505
506 // Creates environment pointers from RES to use in script
fill_envp(dhcpc_result_t * res)507 static int fill_envp(dhcpc_result_t *res)
508 {
509 struct in_addr temp;
510 int size = ARRAY_LEN(options_list), count, ret = -1;
511
512 ret = setenv("interface", state->iface, 1);
513 if (!res) return ret;
514 if (res->ipaddr.s_addr) {
515 temp.s_addr = htonl(res->ipaddr.s_addr);
516 ret = setenv("ip", inet_ntoa(temp), 1);
517 if (ret) return ret;
518 }
519 if (msgopt_list) {
520 for (count = 0; count < size; count++) {
521 if ((msgopt_list[count].len == 0) || (msgopt_list[count].val == NULL)) continue;
522 ret = setenv(msgopt_list[count].key, (char*)msgopt_list[count].val, 1);
523 if (ret) return ret;
524 }
525 }
526 return ret;
527 }
528
529 // Executes Script NAME.
run_script(dhcpc_result_t * res,char * name)530 static void run_script(dhcpc_result_t *res, char *name)
531 {
532 volatile int error = 0;
533 pid_t pid;
534 char *argv[3];
535 struct stat sts;
536 char *script = flag_get(FLAG_s, TT.script, "/usr/share/dhcp/default.script");
537
538 if (stat(script, &sts) == -1 && errno == ENOENT) return;
539 if (fill_envp(res)) {
540 dbg("Failed to create environment variables.");
541 return;
542 }
543 dbg("Executing %s %s\n", script, name);
544 argv[0] = (char*) script;
545 argv[1] = (char*) name;
546 argv[2] = NULL;
547 fflush(NULL);
548
549 pid = vfork();
550 if (pid < 0) {
551 dbg("Fork failed.\n");
552 return;
553 }
554 if (!pid) {
555 execvp(argv[0], argv);
556 error = errno;
557 _exit(111);
558 }
559 if (error) {
560 waitpid(pid, NULL,0);
561 errno = error;
562 perror_msg("script exec failed");
563 }
564 dbg("script complete.\n");
565 }
566
567 // returns a randome ID
getxid(void)568 static uint32_t getxid(void)
569 {
570 uint32_t randnum;
571 int fd = xopen("/dev/urandom", O_RDONLY);
572 xreadall(fd, &randnum, sizeof(randnum));
573 xclose(fd);
574 return randnum;
575 }
576
577 // opens socket in raw mode.
mode_raw(void)578 static int mode_raw(void)
579 {
580 state->mode = MODE_OFF;
581 struct sockaddr_ll sock;
582
583 if (state->sockfd > 0) close(state->sockfd);
584 dbg("Opening raw socket on ifindex %d\n", state->ifindex);
585
586 state->sockfd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
587 if (state->sockfd < 0) {
588 dbg("MODE RAW : socket fail ERROR : %d\n", state->sockfd);
589 return -1;
590 }
591 dbg("Got raw socket fd %d\n", state->sockfd);
592 memset(&sock, 0, sizeof(sock));
593 sock.sll_family = AF_PACKET;
594 sock.sll_protocol = htons(ETH_P_IP);
595 sock.sll_ifindex = state->ifindex;
596
597 if (bind(state->sockfd, (struct sockaddr *) &sock, sizeof(sock))) {
598 dbg("MODE RAW : bind fail.\n");
599 close(state->sockfd);
600 return -1;
601 }
602 state->mode = MODE_RAW;
603 if (setsockopt(state->sockfd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog, sizeof(filter_prog)) < 0)
604 dbg("MODE RAW : filter attach fail.\n");
605
606 dbg("MODE RAW : success\n");
607 return 0;
608 }
609
610 // opens UDP socket
mode_app(void)611 static int mode_app(void)
612 {
613 struct sockaddr_in addr;
614 struct ifreq ifr;
615
616 state->mode = MODE_OFF;
617 if (state->sockfd > 0) close(state->sockfd);
618
619 dbg("Opening listen socket on *:%d %s\n", DHCPC_CLIENT_PORT, state->iface);
620 state->sockfd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
621 if (state->sockfd < 0) {
622 dbg("MODE APP : socket fail ERROR: %d\n", state->sockfd);
623 return -1;
624 }
625 setsockopt(state->sockfd, SOL_SOCKET, SO_REUSEADDR, &set, sizeof(set));
626 if (setsockopt(state->sockfd, SOL_SOCKET, SO_BROADCAST, &set, sizeof(set)) == -1) {
627 dbg("MODE APP : brodcast failed.\n");
628 close(state->sockfd);
629 return -1;
630 }
631 xstrncpy(ifr.ifr_name, state->iface, IFNAMSIZ);
632 ifr.ifr_name[IFNAMSIZ -1] = '\0';
633 setsockopt(state->sockfd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
634
635 memset(&addr, 0, sizeof(addr));
636 addr.sin_family = AF_INET;
637 addr.sin_port = htons(DHCPC_CLIENT_PORT);
638 addr.sin_addr.s_addr = INADDR_ANY ;
639
640 if (bind(state->sockfd, (struct sockaddr *) &addr, sizeof(addr))) {
641 close(state->sockfd);
642 dbg("MODE APP : bind failed.\n");
643 return -1;
644 }
645 state->mode = MODE_APP;
646 dbg("MODE APP : success\n");
647 return 0;
648 }
649
read_raw(void)650 static int read_raw(void)
651 {
652 dhcp_raw_t packet;
653 uint16_t check;
654 int bytes = 0;
655
656 memset(&packet, 0, sizeof(packet));
657 if ((bytes = read(state->sockfd, &packet, sizeof(packet))) < 0) {
658 dbg("\tPacket read error, ignoring\n");
659 return bytes;
660 }
661 if (bytes < (int) (sizeof(packet.iph) + sizeof(packet.udph))) {
662 dbg("\tPacket is too short, ignoring\n");
663 return -2;
664 }
665 if (bytes < ntohs(packet.iph.tot_len)) {
666 dbg("\tOversized packet, ignoring\n");
667 return -2;
668 }
669 // ignore any extra garbage bytes
670 bytes = ntohs(packet.iph.tot_len);
671 // make sure its the right packet for us, and that it passes sanity checks
672 if (packet.iph.protocol != IPPROTO_UDP || packet.iph.version != IPVERSION
673 || packet.iph.ihl != (sizeof(packet.iph) >> 2)
674 || packet.udph.dest != htons(DHCPC_CLIENT_PORT)
675 || ntohs(packet.udph.len) != (uint16_t)(bytes - sizeof(packet.iph))) {
676 dbg("\tUnrelated/bogus packet, ignoring\n");
677 return -2;
678 }
679 // verify IP checksum
680 check = packet.iph.check;
681 packet.iph.check = 0;
682 if (check != dhcp_checksum(&packet.iph, sizeof(packet.iph))) {
683 dbg("\tBad IP header checksum, ignoring\n");
684 return -2;
685 }
686 memset(&packet.iph, 0, ((size_t) &((struct iphdr *)0)->protocol));
687 packet.iph.tot_len = packet.udph.len;
688 check = packet.udph.check;
689 packet.udph.check = 0;
690 if (check && check != dhcp_checksum(&packet, bytes)) {
691 dbg("\tPacket with bad UDP checksum received, ignoring\n");
692 return -2;
693 }
694 memcpy(&state->pdhcp, &packet.dhcp, bytes - (sizeof(packet.iph) + sizeof(packet.udph)));
695 if (state->pdhcp.cookie != htonl(DHCP_MAGIC)) {
696 dbg("\tPacket with bad magic, ignoring\n");
697 return -2;
698 }
699 return bytes - sizeof(packet.iph) - sizeof(packet.udph);
700 }
701
read_app(void)702 static int read_app(void)
703 {
704 int ret;
705
706 memset(&state->pdhcp, 0, sizeof(dhcp_msg_t));
707 if ((ret = read(state->sockfd, &state->pdhcp, sizeof(dhcp_msg_t))) < 0) {
708 dbg("Packet read error, ignoring\n");
709 return ret; /* returns -1 */
710 }
711 if (state->pdhcp.cookie != htonl(DHCP_MAGIC)) {
712 dbg("Packet with bad magic, ignoring\n");
713 return -2;
714 }
715 return ret;
716 }
717
718 // Sends data through raw socket.
send_raw(void)719 static int send_raw(void)
720 {
721 struct sockaddr_ll dest_sll;
722 dhcp_raw_t packet;
723 unsigned padding;
724 int fd, result = -1;
725
726 memset(&packet, 0, sizeof(dhcp_raw_t));
727 memcpy(&packet.dhcp, &state->pdhcp, sizeof(dhcp_msg_t));
728
729 if ((fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
730 dbg("SEND RAW: socket failed\n");
731 return result;
732 }
733 memset(&dest_sll, 0, sizeof(dest_sll));
734 dest_sll.sll_family = AF_PACKET;
735 dest_sll.sll_protocol = htons(ETH_P_IP);
736 dest_sll.sll_ifindex = state->ifindex;
737 dest_sll.sll_halen = 6;
738 memcpy(dest_sll.sll_addr, bmacaddr , 6);
739
740 if (bind(fd, (struct sockaddr *) &dest_sll, sizeof(dest_sll)) < 0) {
741 dbg("SEND RAW: bind failed\n");
742 close(fd);
743 return result;
744 }
745 padding = 308 - 1 - dhcp_opt_size(state->pdhcp.options);
746 packet.iph.protocol = IPPROTO_UDP;
747 packet.iph.saddr = INADDR_ANY;
748 packet.iph.daddr = INADDR_BROADCAST;
749 packet.udph.source = htons(DHCPC_CLIENT_PORT);
750 packet.udph.dest = htons(DHCPC_SERVER_PORT);
751 packet.udph.len = htons(sizeof(dhcp_raw_t) - sizeof(struct iphdr) - padding);
752 packet.iph.tot_len = packet.udph.len;
753 packet.udph.check = dhcp_checksum(&packet, sizeof(dhcp_raw_t) - padding);
754 packet.iph.tot_len = htons(sizeof(dhcp_raw_t) - padding);
755 packet.iph.ihl = sizeof(packet.iph) >> 2;
756 packet.iph.version = IPVERSION;
757 packet.iph.ttl = IPDEFTTL;
758 packet.iph.check = dhcp_checksum(&packet.iph, sizeof(packet.iph));
759
760 result = sendto(fd, &packet, sizeof(dhcp_raw_t) - padding, 0,
761 (struct sockaddr *) &dest_sll, sizeof(dest_sll));
762
763 close(fd);
764 if (result < 0) dbg("SEND RAW: PACKET send error\n");
765 return result;
766 }
767
768 // Sends data through UDP socket.
send_app(void)769 static int send_app(void)
770 {
771 struct sockaddr_in cli;
772 int fd, ret = -1;
773
774 if ((fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
775 dbg("SEND APP: sock failed.\n");
776 return ret;
777 }
778 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &set, sizeof(set));
779
780 memset(&cli, 0, sizeof(cli));
781 cli.sin_family = AF_INET;
782 cli.sin_port = htons(DHCPC_CLIENT_PORT);
783 cli.sin_addr.s_addr = state->pdhcp.ciaddr;
784 if (bind(fd, (struct sockaddr *)&cli, sizeof(cli)) == -1) {
785 dbg("SEND APP: bind failed.\n");
786 goto error_fd;
787 }
788 memset(&cli, 0, sizeof(cli));
789 cli.sin_family = AF_INET;
790 cli.sin_port = htons(DHCPC_SERVER_PORT);
791 cli.sin_addr.s_addr = state->serverid.s_addr;
792 if (connect(fd, (struct sockaddr *)&cli, sizeof(cli)) == -1) {
793 dbg("SEND APP: connect failed.\n");
794 goto error_fd;
795 }
796 int padding = 308 - 1 - dhcp_opt_size(state->pdhcp.options);
797 if((ret = write(fd, &state->pdhcp, sizeof(dhcp_msg_t) - padding)) < 0) {
798 dbg("SEND APP: write failed error %d\n", ret);
799 goto error_fd;
800 }
801 dbg("SEND APP: write success wrote %d\n", ret);
802 error_fd:
803 close(fd);
804 return ret;
805 }
806
807 // Generic signal handler real handling is done in main funcrion.
signal_handler(int sig)808 static void signal_handler(int sig)
809 {
810 unsigned char ch = sig;
811 if (write(sigfd.wr, &ch, 1) != 1) dbg("can't send signal\n");
812 }
813
814 // signal setup for SIGUSR1 SIGUSR2 SIGTERM
setup_signal()815 static int setup_signal()
816 {
817 if (pipe((int *)&sigfd) < 0) {
818 dbg("signal pipe failed\n");
819 return -1;
820 }
821 fcntl(sigfd.wr , F_SETFD, FD_CLOEXEC);
822 fcntl(sigfd.rd , F_SETFD, FD_CLOEXEC);
823 int flags = fcntl(sigfd.wr, F_GETFL);
824 fcntl(sigfd.wr, F_SETFL, flags | O_NONBLOCK);
825 signal(SIGUSR1, signal_handler);
826 signal(SIGUSR2, signal_handler);
827 signal(SIGTERM, signal_handler);
828
829 return 0;
830 }
831
832 // adds client id to dhcp packet
dhcpc_addclientid(uint8_t * optptr)833 static uint8_t *dhcpc_addclientid(uint8_t *optptr)
834 {
835 *optptr++ = DHCP_OPTION_CLIENTID;
836 *optptr++ = 7;
837 *optptr++ = 1;
838 memcpy(optptr, &state->macaddr, 6);
839 return optptr + 6;
840 }
841
842 // adds messege type to dhcp packet
dhcpc_addmsgtype(uint8_t * optptr,uint8_t type)843 static uint8_t *dhcpc_addmsgtype(uint8_t *optptr, uint8_t type)
844 {
845 *optptr++ = DHCP_OPTION_MSG_TYPE;
846 *optptr++ = 1;
847 *optptr++ = type;
848 return optptr;
849 }
850
851 // adds max size to dhcp packet
dhcpc_addmaxsize(uint8_t * optptr,uint16_t size)852 static uint8_t *dhcpc_addmaxsize(uint8_t *optptr, uint16_t size)
853 {
854 *optptr++ = DHCP_OPTION_MAX_SIZE;
855 *optptr++ = 2;
856 memcpy(optptr, &size, 2);
857 return optptr + 2;
858 }
859
dhcpc_addstropt(uint8_t * optptr,uint8_t opcode,char * str,int len)860 static uint8_t *dhcpc_addstropt(uint8_t *optptr, uint8_t opcode, char* str, int len)
861 {
862 *optptr++ = opcode;
863 *optptr++ = len;
864 memcpy(optptr, str, len);
865 return optptr + len;
866 }
867
868 // adds server id to dhcp packet.
dhcpc_addserverid(struct in_addr * serverid,uint8_t * optptr)869 static uint8_t *dhcpc_addserverid(struct in_addr *serverid, uint8_t *optptr)
870 {
871 *optptr++ = DHCP_OPTION_SERVER_ID;
872 *optptr++ = 4;
873 memcpy(optptr, &serverid->s_addr, 4);
874 return optptr + 4;
875 }
876
877 // adds requested ip address to dhcp packet.
dhcpc_addreqipaddr(struct in_addr * ipaddr,uint8_t * optptr)878 static uint8_t *dhcpc_addreqipaddr(struct in_addr *ipaddr, uint8_t *optptr)
879 {
880 *optptr++ = DHCP_OPTION_REQ_IPADDR;
881 *optptr++ = 4;
882 memcpy(optptr, &ipaddr->s_addr, 4);
883 return optptr + 4;
884 }
885
886 // adds hostname to dhcp packet.
dhcpc_addfdnname(uint8_t * optptr,char * hname)887 static uint8_t *dhcpc_addfdnname(uint8_t *optptr, char *hname)
888 {
889 int size = strlen(hname);
890
891 *optptr++ = DHCP_OPTION_FQDN;
892 *optptr++ = size + 3;
893 *optptr++ = 0x1; //flags
894 optptr += 2; // two blank bytes
895 strcpy((char*)optptr, hname); // name
896
897 return optptr + size;
898 }
899
900 // adds request options using -o,-O flag to dhcp packet
dhcpc_addreqoptions(uint8_t * optptr)901 static uint8_t *dhcpc_addreqoptions(uint8_t *optptr)
902 {
903 uint8_t *len;
904
905 *optptr++ = DHCP_OPTION_REQ_LIST;
906 len = optptr;
907 *len = 0;
908 optptr++;
909
910 if (!flag_chk(FLAG_o)) {
911 *len = 4;
912 *optptr++ = DHCP_OPTION_SUBNET_MASK;
913 *optptr++ = DHCP_OPTION_ROUTER;
914 *optptr++ = DHCP_OPTION_DNS_SERVER;
915 *optptr++ = DHCP_OPTION_BROADCAST;
916 }
917 if (flag_chk(FLAG_O)) {
918 memcpy(optptr++, raw_opt, raw_optcount);
919 *len += raw_optcount;
920 }
921 return optptr;
922 }
923
dhcpc_addend(uint8_t * optptr)924 static uint8_t *dhcpc_addend(uint8_t *optptr)
925 {
926 *optptr++ = DHCP_OPTION_END;
927 return optptr;
928 }
929
930 // Sets values of -x options in dhcp discover and request packet.
set_xopt(uint8_t * optptr)931 static uint8_t* set_xopt(uint8_t *optptr)
932 {
933 int count;
934 int size = ARRAY_LEN(options_list);
935 for (count = 0; count < size; count++) {
936 if ((options_list[count].len == 0) || (options_list[count].val == NULL)) continue;
937 *optptr++ = (uint8_t) (options_list[count].code & 0x00FF);
938 *optptr++ = (uint8_t) options_list[count].len;
939 memcpy(optptr, options_list[count].val, options_list[count].len);
940 optptr += options_list[count].len;
941 }
942 return optptr;
943 }
944
get_option_serverid(uint8_t * opt,dhcpc_result_t * presult)945 static uint32_t get_option_serverid (uint8_t *opt, dhcpc_result_t *presult)
946 {
947 uint32_t var = 0;
948 while (*opt != DHCP_OPTION_SERVER_ID) {
949 if (*opt == DHCP_OPTION_END) return var;
950 opt += opt[1] + 2;
951 }
952 memcpy(&var, opt+2, sizeof(uint32_t));
953 state->serverid.s_addr = var;
954 presult->serverid.s_addr = state->serverid.s_addr;
955 presult->serverid.s_addr = ntohl(presult->serverid.s_addr);
956 return var;
957 }
958
get_option_msgtype(uint8_t * opt)959 static uint8_t get_option_msgtype(uint8_t *opt)
960 {
961 uint32_t var = 0;
962 while (*opt != DHCP_OPTION_MSG_TYPE) {
963 if (*opt == DHCP_OPTION_END) return var;
964 opt += opt[1] + 2;
965 }
966 memcpy(&var, opt+2, sizeof(uint8_t));
967 return var;
968 }
969
get_option_lease(uint8_t * opt,dhcpc_result_t * presult)970 static uint8_t get_option_lease(uint8_t *opt, dhcpc_result_t *presult)
971 {
972 uint32_t var = 0;
973 while (*opt != DHCP_OPTION_LEASE_TIME) {
974 if (*opt == DHCP_OPTION_END) return var;
975 opt += opt[1] + 2;
976 }
977 memcpy(&var, opt+2, sizeof(uint32_t));
978 var = htonl(var);
979 presult->lease_time = var;
980 return var;
981 }
982
983
984 // sends dhcp msg of MSGTYPE
dhcpc_sendmsg(int msgtype)985 static int dhcpc_sendmsg(int msgtype)
986 {
987 uint8_t *pend;
988 struct in_addr rqsd;
989 char *vendor;
990
991 // Create the common message header settings
992 memset(&state->pdhcp, 0, sizeof(dhcp_msg_t));
993 state->pdhcp.op = DHCP_REQUEST;
994 state->pdhcp.htype = DHCP_HTYPE_ETHERNET;
995 state->pdhcp.hlen = 6;
996 state->pdhcp.xid = xid;
997 memcpy(state->pdhcp.chaddr, state->macaddr, 6);
998 memset(&state->pdhcp.chaddr[6], 0, 10);
999 state->pdhcp.cookie = htonl(DHCP_MAGIC);;
1000
1001 // Add the common header options
1002 pend = state->pdhcp.options;
1003 pend = dhcpc_addmsgtype(pend, msgtype);
1004
1005 if (!flag_chk(FLAG_C)) pend = dhcpc_addclientid(pend);
1006 // Handle the message specific settings
1007 switch (msgtype) {
1008 case DHCPDISCOVER: // Broadcast DISCOVER message to all servers
1009 state->pdhcp.flags = htons(BOOTP_BROADCAST); // Broadcast bit.
1010 if (flag_chk(FLAG_r)) {
1011 inet_aton(TT.req_ip, &rqsd);
1012 pend = dhcpc_addreqipaddr(&rqsd, pend);
1013 }
1014 pend = dhcpc_addmaxsize(pend, htons(sizeof(dhcp_raw_t)));
1015 vendor = flag_get(FLAG_V, TT.vendor_cls, "toybox\0");
1016 pend = dhcpc_addstropt(pend, DHCP_OPTION_VENDOR, vendor, strlen(vendor));
1017 if (flag_chk(FLAG_H)) pend = dhcpc_addstropt(pend, DHCP_OPTION_HOST_NAME, TT.hostname, strlen(TT.hostname));
1018 if (flag_chk(FLAG_F)) pend = dhcpc_addfdnname(pend, TT.fdn_name);
1019 if ((!flag_chk(FLAG_o)) || flag_chk(FLAG_O)) pend = dhcpc_addreqoptions(pend);
1020 if (flag_chk(FLAG_x)) pend = set_xopt(pend);
1021 break;
1022 case DHCPREQUEST: // Send REQUEST message to the server that sent the *first* OFFER
1023 state->pdhcp.flags = htons(BOOTP_BROADCAST); // Broadcast bit.
1024 if (state->status == STATE_RENEWING) memcpy(&state->pdhcp.ciaddr, &state->ipaddr.s_addr, 4);
1025 pend = dhcpc_addmaxsize(pend, htons(sizeof(dhcp_raw_t)));
1026 rqsd.s_addr = htonl(server);
1027 pend = dhcpc_addserverid(&rqsd, pend);
1028 pend = dhcpc_addreqipaddr(&state->ipaddr, pend);
1029 vendor = flag_get(FLAG_V, TT.vendor_cls, "toybox\0");
1030 pend = dhcpc_addstropt(pend, DHCP_OPTION_VENDOR, vendor, strlen(vendor));
1031 if (flag_chk(FLAG_H)) pend = dhcpc_addstropt(pend, DHCP_OPTION_HOST_NAME, TT.hostname, strlen(TT.hostname));
1032 if (flag_chk(FLAG_F)) pend = dhcpc_addfdnname(pend, TT.fdn_name);
1033 if ((!flag_chk(FLAG_o)) || flag_chk(FLAG_O)) pend = dhcpc_addreqoptions(pend);
1034 if (flag_chk(FLAG_x)) pend = set_xopt(pend);
1035 break;
1036 case DHCPRELEASE: // Send RELEASE message to the server.
1037 memcpy(&state->pdhcp.ciaddr, &state->ipaddr.s_addr, 4);
1038 rqsd.s_addr = htonl(server);
1039 pend = dhcpc_addserverid(&rqsd, pend);
1040 break;
1041 default:
1042 return -1;
1043 }
1044 pend = dhcpc_addend(pend);
1045
1046 if (state->mode == MODE_APP) return send_app();
1047 return send_raw();
1048 }
1049
1050 /*
1051 * parses options from received dhcp packet at OPTPTR and
1052 * stores result in PRESULT or MSGOPT_LIST
1053 */
dhcpc_parseoptions(dhcpc_result_t * presult,uint8_t * optptr)1054 static uint8_t dhcpc_parseoptions(dhcpc_result_t *presult, uint8_t *optptr)
1055 {
1056 uint8_t type = 0, *options, overloaded = 0;;
1057 uint16_t flag = 0;
1058 uint32_t convtmp = 0;
1059 char *dest, *pfx;
1060 struct in_addr addr;
1061 int count, optlen, size = ARRAY_LEN(options_list);
1062
1063 if (flag_chk(FLAG_x)) {
1064 if(msgopt_list){
1065 for (count = 0; count < size; count++){
1066 if(msgopt_list[count].val) free(msgopt_list[count].val);
1067 msgopt_list[count].val = NULL;
1068 msgopt_list[count].len = 0;
1069 }
1070 } else {
1071 msgopt_list = xmalloc(sizeof(options_list));
1072 memcpy(msgopt_list, options_list, sizeof(options_list));
1073 for (count = 0; count < size; count++) {
1074 msgopt_list[count].len = 0;
1075 msgopt_list[count].val = NULL;
1076 }
1077 }
1078 } else {
1079 msgopt_list = options_list;
1080 for (count = 0; count < size; count++) {
1081 msgopt_list[count].len = 0;
1082 if(msgopt_list[count].val) free(msgopt_list[count].val);
1083 msgopt_list[count].val = NULL;
1084 }
1085 }
1086
1087 while (*optptr != DHCP_OPTION_END) {
1088 if (*optptr == DHCP_OPTION_PADDING) {
1089 optptr++;
1090 continue;
1091 }
1092 if (*optptr == DHCP_OPTION_OVERLOAD) {
1093 overloaded = optptr[2];
1094 optptr += optptr[1] + 2;
1095 continue;
1096 }
1097 for (count = 0, flag = 0; count < size; count++) {
1098 if ((msgopt_list[count].code & 0X00FF) == *optptr) {
1099 flag = (msgopt_list[count].code & 0XFF00);
1100 break;
1101 }
1102 }
1103 switch (flag) {
1104 case DHCP_NUM32:
1105 memcpy(&convtmp, &optptr[2], sizeof(uint32_t));
1106 convtmp = htonl(convtmp);
1107 sprintf(toybuf, "%u", convtmp);
1108 msgopt_list[count].val = strdup(toybuf);
1109 msgopt_list[count].len = strlen(toybuf);
1110 break;
1111 case DHCP_NUM16:
1112 memcpy(&convtmp, &optptr[2], sizeof(uint16_t));
1113 convtmp = htons(convtmp);
1114 sprintf(toybuf, "%u", convtmp);
1115 msgopt_list[count].val = strdup(toybuf);
1116 msgopt_list[count].len = strlen(toybuf);
1117 break;
1118 case DHCP_NUM8:
1119 memcpy(&convtmp, &optptr[2], sizeof(uint8_t));
1120 sprintf(toybuf, "%u", convtmp);
1121 msgopt_list[count].val = strdup(toybuf);
1122 msgopt_list[count].len = strlen(toybuf);
1123 break;
1124 case DHCP_IP:
1125 memcpy(&convtmp, &optptr[2], sizeof(uint32_t));
1126 addr.s_addr = convtmp;
1127 sprintf(toybuf, "%s", inet_ntoa(addr));
1128 msgopt_list[count].val = strdup(toybuf);
1129 msgopt_list[count].len = strlen(toybuf);
1130 break;
1131 case DHCP_STRING:
1132 sprintf(toybuf, "%.*s", optptr[1], &optptr[2]);
1133 msgopt_list[count].val = strdup(toybuf);
1134 msgopt_list[count].len = strlen(toybuf);
1135 break;
1136 case DHCP_IPLIST:
1137 optlen = optptr[1];
1138 dest = toybuf;
1139 while (optlen) {
1140 memcpy(&convtmp, &optptr[2], sizeof(uint32_t));
1141 addr.s_addr = convtmp;
1142 dest += sprintf(dest, "%s ", inet_ntoa(addr));
1143 optlen -= 4;
1144 }
1145 *(dest - 1) = '\0';
1146 msgopt_list[count].val = strdup(toybuf);
1147 msgopt_list[count].len = strlen(toybuf);
1148 break;
1149 case DHCP_STRLST: //FIXME: do smthing.
1150 case DHCP_IPPLST:
1151 break;
1152 case DHCP_STCRTS:
1153 pfx = "";
1154 dest = toybuf;
1155 options = &optptr[2];
1156 optlen = optptr[1];
1157
1158 while (optlen >= 1 + 4) {
1159 uint32_t nip = 0;
1160 int bytes;
1161 uint8_t *p_tmp;
1162 unsigned mask = *options;
1163
1164 if (mask > 32) break;
1165 optlen--;
1166 p_tmp = (void*) &nip;
1167 bytes = (mask + 7) / 8;
1168 while (--bytes >= 0) {
1169 *p_tmp++ = *options++;
1170 optlen--;
1171 }
1172 if (optlen < 4) break;
1173 dest += sprintf(dest, "%s%u.%u.%u.%u", pfx, ((uint8_t*) &nip)[0],
1174 ((uint8_t*) &nip)[1], ((uint8_t*) &nip)[2], ((uint8_t*) &nip)[3]);
1175 pfx = " ";
1176 dest += sprintf(dest, "/%u ", mask);
1177 dest += sprintf(dest, "%u.%u.%u.%u", options[0], options[1], options[2], options[3]);
1178 options += 4;
1179 optlen -= 4;
1180 }
1181 msgopt_list[count].val = strdup(toybuf);
1182 msgopt_list[count].len = strlen(toybuf);
1183 break;
1184 default: break;
1185 }
1186 optptr += optptr[1] + 2;
1187 }
1188 if ((overloaded == 1) || (overloaded == 3)) dhcpc_parseoptions(presult, optptr);
1189 if ((overloaded == 2) || (overloaded == 3)) dhcpc_parseoptions(presult, optptr);
1190 return type;
1191 }
1192
1193 // parses recvd messege to check that it was for us.
dhcpc_parsemsg(dhcpc_result_t * presult)1194 static uint8_t dhcpc_parsemsg(dhcpc_result_t *presult)
1195 {
1196 if (state->pdhcp.op == DHCP_REPLY
1197 && !memcmp(state->pdhcp.chaddr, state->macaddr, 6)
1198 && !memcmp(&state->pdhcp.xid, &xid, sizeof(xid))) {
1199 memcpy(&presult->ipaddr.s_addr, &state->pdhcp.yiaddr, 4);
1200 presult->ipaddr.s_addr = ntohl(presult->ipaddr.s_addr);
1201 return get_option_msgtype(state->pdhcp.options);
1202 }
1203 return 0;
1204 }
1205
1206 // Sends a IP renew request.
renew(void)1207 static void renew(void)
1208 {
1209 infomsg(infomode, "Performing a DHCP renew");
1210 switch (state->status) {
1211 case STATE_INIT:
1212 break;
1213 case STATE_BOUND:
1214 mode_raw();
1215 case STATE_RENEWING: // FALLTHROUGH
1216 case STATE_REBINDING: // FALLTHROUGH
1217 state->status = STATE_RENEW_REQUESTED;
1218 break;
1219 case STATE_RENEW_REQUESTED:
1220 run_script(NULL, "deconfig");
1221 case STATE_REQUESTING: // FALLTHROUGH
1222 case STATE_RELEASED: // FALLTHROUGH
1223 mode_raw();
1224 state->status = STATE_INIT;
1225 break;
1226 default: break;
1227 }
1228 }
1229
1230 // Sends a IP release request.
release(void)1231 static void release(void)
1232 {
1233 char buffer[sizeof("255.255.255.255\0")];
1234 struct in_addr temp_addr;
1235
1236 mode_app();
1237 // send release packet
1238 if (state->status == STATE_BOUND || state->status == STATE_RENEWING || state->status == STATE_REBINDING) {
1239 temp_addr.s_addr = htonl(server);
1240 xstrncpy(buffer, inet_ntoa(temp_addr), sizeof(buffer));
1241 temp_addr.s_addr = state->ipaddr.s_addr;
1242 infomsg( infomode, "Unicasting a release of %s to %s", inet_ntoa(temp_addr), buffer);
1243 dhcpc_sendmsg(DHCPRELEASE);
1244 run_script(NULL, "deconfig");
1245 }
1246 infomsg(infomode, "Entering released state");
1247 close(state->sockfd);
1248 state->sockfd = -1;
1249 state->mode = MODE_OFF;
1250 state->status = STATE_RELEASED;
1251 }
1252
free_option_stores(void)1253 static void free_option_stores(void)
1254 {
1255 int count, size = ARRAY_LEN(options_list);
1256 for (count = 0; count < size; count++)
1257 if (options_list[count].val) free(options_list[count].val);
1258 if(flag_chk(FLAG_x)){
1259 for (count = 0; count < size; count++)
1260 if (msgopt_list[count].val) free(msgopt_list[count].val);
1261 free(msgopt_list);
1262 }
1263 }
1264
dhcp_main(void)1265 void dhcp_main(void)
1266 {
1267 struct timeval tv;
1268 int retval, bufflen = 0;
1269 dhcpc_result_t result;
1270 uint8_t packets = 0, retries = 0;
1271 uint32_t timeout = 0, waited = 0;
1272 fd_set rfds;
1273
1274 xid = 0;
1275 setlinebuf(stdout);
1276 dbg = dummy;
1277 if (flag_chk(FLAG_v)) dbg = xprintf;
1278 if (flag_chk(FLAG_p)) write_pid(TT.pidfile);
1279 retries = flag_get(FLAG_t, TT.retries, 3);
1280 if (flag_chk(FLAG_S)) {
1281 openlog("UDHCPC :", LOG_PID, LOG_DAEMON);
1282 infomode |= LOG_SYSTEM;
1283 }
1284 infomsg(infomode, "dhcp started");
1285 if (flag_chk(FLAG_O)) {
1286 while (TT.req_opt) {
1287 raw_opt[raw_optcount] = (uint8_t) strtoopt(TT.req_opt->arg, 1);
1288 raw_optcount++;
1289 TT.req_opt = TT.req_opt->next;
1290 }
1291 }
1292 if (flag_chk(FLAG_x)) {
1293 while (TT.pkt_opt) {
1294 (void) strtoopt(TT.pkt_opt->arg, 0);
1295 TT.pkt_opt = TT.pkt_opt->next;
1296 }
1297 }
1298 memset(&result, 0, sizeof(dhcpc_result_t));
1299 state = (dhcpc_state_t*) xmalloc(sizeof(dhcpc_state_t));
1300 memset(state, 0, sizeof(dhcpc_state_t));
1301 state->iface = flag_get(FLAG_i, TT.iface, "eth0");
1302
1303 if (get_interface(state->iface, &state->ifindex, NULL, state->macaddr))
1304 perror_exit("Failed to get interface %s", state->iface);
1305
1306 run_script(NULL, "deconfig");
1307 setup_signal();
1308 state->status = STATE_INIT;
1309 mode_raw();
1310 fcntl(state->sockfd, F_SETFD, FD_CLOEXEC);
1311
1312 for (;;) {
1313 FD_ZERO(&rfds);
1314 if (state->sockfd >= 0) FD_SET(state->sockfd, &rfds);
1315 FD_SET(sigfd.rd, &rfds);
1316 tv.tv_sec = timeout - waited;
1317 tv.tv_usec = 0;
1318 retval = 0;
1319
1320 int maxfd = (sigfd.rd > state->sockfd)? sigfd.rd : state->sockfd;
1321 dbg("select wait ....\n");
1322 uint32_t timestmp = time(NULL);
1323 if((retval = select(maxfd + 1, &rfds, NULL, NULL, &tv)) < 0) {
1324 if (errno == EINTR) {
1325 waited += (unsigned) time(NULL) - timestmp;
1326 continue;
1327 }
1328 perror_exit("Error in select");
1329 }
1330 if (!retval) { // Timed out
1331 if (get_interface(state->iface, &state->ifindex, NULL, state->macaddr))
1332 error_exit("Interface lost %s\n", state->iface);
1333
1334 switch (state->status) {
1335 case STATE_INIT:
1336 if (packets < retries) {
1337 if (!packets) xid = getxid();
1338 run_script(NULL, "deconfig");
1339 infomsg(infomode, "Sending discover...");
1340 dhcpc_sendmsg(DHCPDISCOVER);
1341 server = 0;
1342 timeout = flag_get(FLAG_T, TT.timeout, 3);
1343 waited = 0;
1344 packets++;
1345 continue;
1346 }
1347 lease_fail:
1348 run_script(NULL,"leasefail");
1349 if (flag_chk(FLAG_n)) {
1350 infomsg(infomode, "Lease failed. Exiting");
1351 goto ret_with_sockfd;
1352 }
1353 if (flag_chk(FLAG_b)) {
1354 infomsg(infomode, "Lease failed. Going Daemon mode");
1355 daemon(0, 0);
1356 if (flag_chk(FLAG_p)) write_pid(TT.pidfile);
1357 toys.optflags &= ~FLAG_b;
1358 toys.optflags |= FLAG_f;
1359 }
1360 timeout = flag_get(FLAG_A, TT.tryagain, 20);
1361 waited = 0;
1362 packets = 0;
1363 continue;
1364 case STATE_REQUESTING:
1365 if (packets < retries) {
1366 memcpy(&state->ipaddr.s_addr,&state->pdhcp.yiaddr, 4);
1367 dhcpc_sendmsg(DHCPREQUEST);
1368 infomsg(infomode, "Sending select for %d.%d.%d.%d...",
1369 (result.ipaddr.s_addr >> 24) & 0xff, (result.ipaddr.s_addr >> 16) & 0xff, (result.ipaddr.s_addr >> 8) & 0xff, (result.ipaddr.s_addr) & 0xff);
1370 timeout = flag_get(FLAG_T, TT.timeout, 3);
1371 waited = 0;
1372 packets++;
1373 continue;
1374 }
1375 mode_raw();
1376 state->status = STATE_INIT;
1377 goto lease_fail;
1378 case STATE_BOUND:
1379 state->status = STATE_RENEWING;
1380 dbg("Entering renew state\n");
1381 // FALLTHROUGH
1382 case STATE_RENEW_REQUESTED: // FALLTHROUGH
1383 case STATE_RENEWING:
1384 renew_requested:
1385 if (timeout > 60) {
1386 dhcpc_sendmsg(DHCPREQUEST);
1387 timeout >>= 1;
1388 waited = 0;
1389 continue;
1390 }
1391 dbg("Entering rebinding state\n");
1392 state->status = STATE_REBINDING;
1393 // FALLTHROUGH
1394 case STATE_REBINDING:
1395 mode_raw();
1396 if (timeout > 0) {
1397 dhcpc_sendmsg(DHCPREQUEST);
1398 timeout >>= 1;
1399 waited = 0;
1400 continue;
1401 }
1402 infomsg(infomode, "Lease lost, entering INIT state");
1403 run_script(NULL, "deconfig");
1404 state->status = STATE_INIT;
1405 timeout = 0;
1406 waited = 0;
1407 packets = 0;
1408 continue;
1409 default: break;
1410 }
1411 timeout = INT_MAX;
1412 waited = 0;
1413 continue;
1414 }
1415 if (FD_ISSET(sigfd.rd, &rfds)) { // Some Activity on RDFDs : is signal
1416 unsigned char sig;
1417 if (read(sigfd.rd, &sig, 1) != 1) {
1418 dbg("signal read failed.\n");
1419 continue;
1420 }
1421 switch (sig) {
1422 case SIGUSR1:
1423 infomsg(infomode, "Received SIGUSR1");
1424 renew();
1425 packets = 0;
1426 waited = 0;
1427 if (state->status == STATE_RENEW_REQUESTED) goto renew_requested;
1428 if (state->status == STATE_INIT) timeout = 0;
1429 continue;
1430 case SIGUSR2:
1431 infomsg(infomode, "Received SIGUSR2");
1432 release();
1433 timeout = INT_MAX;
1434 waited = 0;
1435 packets = 0;
1436 continue;
1437 case SIGTERM:
1438 infomsg(infomode, "Received SIGTERM");
1439 if (flag_chk(FLAG_R)) release();
1440 goto ret_with_sockfd;
1441 default: break;
1442 }
1443 }
1444 if (FD_ISSET(state->sockfd, &rfds)) { // Some Activity on RDFDs : is socket
1445 dbg("main sock read\n");
1446 uint8_t msgType;
1447 if (state->mode == MODE_RAW) bufflen = read_raw();
1448 if (state->mode == MODE_APP) bufflen = read_app();
1449 if (bufflen < 0) {
1450 if (state->mode == MODE_RAW) mode_raw();
1451 if (state->mode == MODE_APP) mode_app();
1452 continue;
1453 }
1454 waited += time(NULL) - timestmp;
1455 memset(&result, 0, sizeof(dhcpc_result_t));
1456 msgType = dhcpc_parsemsg(&result);
1457 if (msgType != DHCPNAK && result.ipaddr.s_addr == 0 ) continue; // no ip for me ignore
1458 if (!msgType || !get_option_serverid(state->pdhcp.options, &result)) continue; //no server id ignore
1459 if (msgType == DHCPOFFER && server == 0) server = result.serverid.s_addr; // select the server
1460 if (result.serverid.s_addr != server) continue; // not from the server we requested ignore
1461 dhcpc_parseoptions(&result, state->pdhcp.options);
1462 get_option_lease(state->pdhcp.options, &result);
1463
1464 switch (state->status) {
1465 case STATE_INIT:
1466 if (msgType == DHCPOFFER) {
1467 state->status = STATE_REQUESTING;
1468 mode_raw();
1469 timeout = 0;
1470 waited = 0;
1471 packets = 0;
1472 }
1473 continue;
1474 case STATE_REQUESTING: // FALLTHROUGH
1475 case STATE_RENEWING: // FALLTHROUGH
1476 case STATE_RENEW_REQUESTED: // FALLTHROUGH
1477 case STATE_REBINDING:
1478 if (msgType == DHCPACK) {
1479 timeout = result.lease_time / 2;
1480 run_script(&result, state->status == STATE_REQUESTING ? "bound" : "renew");
1481 state->status = STATE_BOUND;
1482 infomsg(infomode, "Lease of %d.%d.%d.%d obtained, lease time %d from server %d.%d.%d.%d",
1483 (result.ipaddr.s_addr >> 24) & 0xff, (result.ipaddr.s_addr >> 16) & 0xff, (result.ipaddr.s_addr >> 8) & 0xff, (result.ipaddr.s_addr) & 0xff,
1484 result.lease_time,
1485 (result.serverid.s_addr >> 24) & 0xff, (result.serverid.s_addr >> 16) & 0xff, (result.serverid.s_addr >> 8) & 0xff, (result.serverid.s_addr) & 0xff);
1486 if (flag_chk(FLAG_q)) {
1487 if (flag_chk(FLAG_R)) release();
1488 goto ret_with_sockfd;
1489 }
1490 toys.optflags &= ~FLAG_n;
1491 if (!flag_chk(FLAG_f)) {
1492 daemon(0, 0);
1493 toys.optflags |= FLAG_f;
1494 if (flag_chk(FLAG_p)) write_pid(TT.pidfile);
1495 }
1496 waited = 0;
1497 continue;
1498 } else if (msgType == DHCPNAK) {
1499 dbg("NACK received.\n");
1500 run_script(&result, "nak");
1501 if (state->status != STATE_REQUESTING) run_script(NULL, "deconfig");
1502 mode_raw();
1503 sleep(3);
1504 state->status = STATE_INIT;
1505 state->ipaddr.s_addr = 0;
1506 server = 0;
1507 timeout = 0;
1508 packets = 0;
1509 waited = 0;
1510 }
1511 continue;
1512 default: break;
1513 }
1514 }
1515 }
1516 ret_with_sockfd:
1517 if (CFG_TOYBOX_FREE) {
1518 free_option_stores();
1519 if (state->sockfd > 0) close(state->sockfd);
1520 free(state);
1521 }
1522 }
1523