Fix script environment variable setting for empty lists
[odhcp6c.git] / src / script.c
1 /**
2  * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License v2 as published by
6  * the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  *
13  */
14
15 #include <stdio.h>
16 #include <netdb.h>
17 #include <resolv.h>
18 #include <stdlib.h>
19 #include <string.h>
20 #include <syslog.h>
21 #include <signal.h>
22 #include <unistd.h>
23 #include <inttypes.h>
24 #include <arpa/inet.h>
25 #include <sys/wait.h>
26 #include <netinet/in.h>
27
28 #include "odhcp6c.h"
29
30 static const char hexdigits[] = "0123456789abcdef";
31 static const int8_t hexvals[] = {
32     -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
33     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
34     -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
35      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
36     -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
37     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
38     -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
39     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
40 };
41
42
43 static char action[16] = "";
44 static char *argv[4] = {NULL, NULL, action, NULL};
45 static volatile pid_t running = 0;
46 static time_t started;
47
48
49 static void script_sighandle(int signal)
50 {
51         if (signal == SIGCHLD) {
52                 pid_t child;
53                 while ((child = waitpid(-1, NULL, WNOHANG)) > 0)
54                         if (running == child)
55                                 running = 0;
56         }
57 }
58
59 int script_init(const char *path, const char *ifname)
60 {
61         argv[0] = (char*)path;
62         argv[1] = (char*)ifname;
63         signal(SIGCHLD, script_sighandle);
64         return 0;
65 }
66
67
68 ssize_t script_unhexlify(uint8_t *dst, size_t len, const char *src)
69 {
70         size_t c;
71         for (c = 0; c < len && src[0] && src[1]; ++c) {
72                 int8_t x = (int8_t)*src++;
73                 int8_t y = (int8_t)*src++;
74                 if (x < 0 || (x = hexvals[x]) < 0
75                                 || y < 0 || (y = hexvals[y]) < 0)
76                         return -1;
77                 dst[c] = x << 4 | y;
78                 while (((int8_t)*src) < 0 ||
79                                 (*src && hexvals[(uint8_t)*src] < 0))
80                         src++;
81         }
82
83         return c;
84 }
85
86
87 static void script_hexlify(char *dst, const uint8_t *src, size_t len) {
88         for (size_t i = 0; i < len; ++i) {
89                 *dst++ = hexdigits[src[i] >> 4];
90                 *dst++ = hexdigits[src[i] & 0x0f];
91         }
92         *dst = 0;
93 }
94
95
96 static void ipv6_to_env(const char *name,
97                 const struct in6_addr *addr, size_t cnt)
98 {
99         size_t buf_len = strlen(name);
100         char *buf = realloc(NULL, cnt * INET6_ADDRSTRLEN + buf_len + 2);
101         memcpy(buf, name, buf_len);
102         buf[buf_len++] = '=';
103         for (size_t i = 0; i < cnt; ++i) {
104                 inet_ntop(AF_INET6, &addr[i], &buf[buf_len], INET6_ADDRSTRLEN);
105                 buf_len += strlen(&buf[buf_len]);
106                 buf[buf_len++] = ' ';
107         }
108         if (buf[buf_len - 1] == ' ')
109                 buf_len--;
110         buf[buf_len] = '\0';
111         putenv(buf);
112 }
113
114
115 static void fqdn_to_env(const char *name, const uint8_t *fqdn, size_t len)
116 {
117         size_t buf_len = strlen(name);
118         size_t buf_size = len + buf_len + 2;
119         const uint8_t *fqdn_end = fqdn + len;
120         char *buf = realloc(NULL, len + buf_len + 2);
121         memcpy(buf, name, buf_len);
122         buf[buf_len++] = '=';
123         while (fqdn < fqdn_end) {
124                 int l = dn_expand(fqdn, fqdn_end, fqdn, &buf[buf_len], buf_size - buf_len);
125                 if (l <= 0)
126                         break;
127                 fqdn += l;
128                 buf_len += strlen(&buf[buf_len]);
129                 buf[buf_len++] = ' ';
130         }
131         if (buf[buf_len - 1] == ' ')
132                 buf_len--;
133         buf[buf_len] = '\0';
134         putenv(buf);
135 }
136
137 static void bin_to_env(uint8_t *opts, size_t len)
138 {
139         uint8_t *oend = opts + len, *odata;
140         uint16_t otype, olen;
141         dhcpv6_for_each_option(opts, oend, otype, olen, odata) {
142                 char *buf = realloc(NULL, 14 + (olen * 2));
143                 size_t buf_len = 0;
144
145                 snprintf(buf, 14, "OPTION_%hu=", otype);
146                 buf_len += strlen(buf);
147
148                 script_hexlify(&buf[buf_len], odata, olen);
149                 putenv(buf);
150         }
151 }
152
153 enum entry_type {
154         ENTRY_ADDRESS,
155         ENTRY_HOST,
156         ENTRY_ROUTE,
157         ENTRY_PREFIX
158 };
159
160 static void entry_to_env(const char *name, const void *data, size_t len, enum entry_type type)
161 {
162         size_t buf_len = strlen(name);
163         const struct odhcp6c_entry *e = data;
164         // Worst case: ENTRY_PREFIX with iaid != 1 and exclusion
165         const size_t max_entry_len = (INET6_ADDRSTRLEN-1 + 5 + 22 + 15 + 10 +
166                                       INET6_ADDRSTRLEN-1 + 11 + 1);
167         char *buf = realloc(NULL, buf_len + 2 + (len / sizeof(*e)) * max_entry_len);
168         memcpy(buf, name, buf_len);
169         buf[buf_len++] = '=';
170
171         for (size_t i = 0; i < len / sizeof(*e); ++i) {
172                 inet_ntop(AF_INET6, &e[i].target, &buf[buf_len], INET6_ADDRSTRLEN);
173                 buf_len += strlen(&buf[buf_len]);
174                 if (type != ENTRY_HOST) {
175                         snprintf(&buf[buf_len], 6, "/%"PRIu16, e[i].length);
176                         buf += strlen(&buf[buf_len]);
177                         if (type == ENTRY_ROUTE) {
178                                 buf[buf_len++] = ',';
179                                 if (!IN6_IS_ADDR_UNSPECIFIED(&e[i].router)) {
180                                         inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
181                                         buf_len += strlen(&buf[buf_len]);
182                                 }
183                                 snprintf(&buf[buf_len], 23, ",%u,%u", e[i].valid, e[i].priority);
184                                 buf += strlen(&buf[buf_len]);
185                         } else {
186                                 snprintf(&buf[buf_len], 23, ",%u,%u", e[i].preferred, e[i].valid);
187                                 buf += strlen(&buf[buf_len]);
188                         }
189
190                         if (type == ENTRY_PREFIX && ntohl(e[i].iaid) != 1) {
191                                 snprintf(&buf[buf_len], 16, ",class=%08x", ntohl(e[i].iaid));
192                                 buf += strlen(&buf[buf_len]);
193                         }
194
195                         if (type == ENTRY_PREFIX && e[i].priority) {
196                                 // priority and router are abused for prefix exclusion
197                                 snprintf(&buf[buf_len], 11, ",excluded=");
198                                 buf_len += strlen(&buf[buf_len]);
199                                 inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
200                                 buf_len += strlen(&buf[buf_len]);
201                                 snprintf(&buf[buf_len], 12, "/%u", e[i].priority);
202                                 buf_len += strlen(&buf[buf_len]);
203                         }
204                 }
205                 buf[buf_len++] = ' ';
206         }
207
208         if (buf[buf_len - 1] == ' ')
209                 buf_len--;
210         buf[buf_len] = '\0';
211         putenv(buf);
212 }
213
214
215 static void search_to_env(const char *name, const uint8_t *start, size_t len)
216 {
217         size_t buf_len = strlen(name);
218         char *buf = realloc(NULL, buf_len + 2 + len);
219         char *c = mempcpy(buf, name, buf_len);
220         *c++ = '=';
221
222         for (struct odhcp6c_entry *e = (struct odhcp6c_entry*)start;
223                                 (uint8_t*)e < &start[len] && &e->auxtarget[e->auxlen] <= &start[len];
224                                 e = (struct odhcp6c_entry*)(&e->auxtarget[e->auxlen])) {
225                 c = mempcpy(c, e->auxtarget, e->auxlen);
226                 *c++ = ' ';
227         }
228
229         if (c[-1] == ' ')
230                 c--;
231         *c = '\0';
232         putenv(buf);
233 }
234
235
236 static void int_to_env(const char *name, int value)
237 {
238         size_t len = 13 + strlen(name);
239         char *buf = realloc(NULL, len);
240         snprintf(buf, len, "%s=%d", name, value);
241         putenv(buf);
242 }
243
244
245 static void s46_to_env_portparams(const uint8_t *data, size_t len, FILE *fp)
246 {
247         uint8_t *odata;
248         uint16_t otype, olen;
249         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
250                 if (otype == DHCPV6_OPT_S46_PORTPARAMS &&
251                                 olen == sizeof(struct dhcpv6_s46_portparams)) {
252                         struct dhcpv6_s46_portparams *params = (void*)odata;
253                         fprintf(fp, "offset=%d,psidlen=%d,psid=%d,",
254                                         params->offset, params->psid_len, ntohs(params->psid));
255                 }
256         }
257 }
258
259
260 static void s46_to_env(enum odhcp6c_state state, const uint8_t *data, size_t len)
261 {
262         const char *name = (state == STATE_S46_MAPE) ? "MAPE" :
263                         (state == STATE_S46_MAPT) ? "MAPT" : "LW4O6";
264
265         if (len == 0)
266                 return;
267
268         char *str;
269         size_t strsize;
270
271         FILE *fp = open_memstream(&str, &strsize);
272         fputs(name, fp);
273         fputc('=', fp);
274
275         const char *type = (state == STATE_S46_MAPE) ? "map-e" :
276                         (state == STATE_S46_MAPT) ? "map-t" : "lw4o6";
277
278         uint8_t *odata;
279         uint16_t otype, olen;
280         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
281                 struct dhcpv6_s46_rule *rule = (struct dhcpv6_s46_rule*)odata;
282                 struct dhcpv6_s46_v4v6bind *bind = (struct dhcpv6_s46_v4v6bind*)odata;
283
284                 if (state != STATE_S46_LW && otype == DHCPV6_OPT_S46_RULE &&
285                                 olen >= sizeof(struct dhcpv6_s46_rule)) {
286                         char buf4[INET_ADDRSTRLEN];
287                         char buf6[INET6_ADDRSTRLEN];
288                         struct in6_addr in6 = IN6ADDR_ANY_INIT;
289
290                         size_t prefix6len = rule->prefix6_len;
291                         prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
292
293                         if (prefix6len > sizeof(in6) ||
294                             olen < sizeof(struct dhcpv6_s46_rule) + prefix6len)
295                                 continue;
296
297                         memcpy(&in6, rule->ipv6_prefix, prefix6len);
298
299                         inet_ntop(AF_INET, &rule->ipv4_prefix, buf4, sizeof(buf4));
300                         inet_ntop(AF_INET6, &in6, buf6, sizeof(buf6));
301
302                         if (rule->flags & 1)
303                                 fputs("fmr,", fp);
304
305                         fprintf(fp, "type=%s,ealen=%d,prefix4len=%d,prefix6len=%d,ipv4prefix=%s,ipv6prefix=%s,",
306                                         type, rule->ea_len, rule->prefix4_len, rule->prefix6_len, buf4, buf6);
307
308                         s46_to_env_portparams(&rule->ipv6_prefix[prefix6len],
309                                         olen - sizeof(*rule) - prefix6len, fp);
310
311                         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
312                                 if (state != STATE_S46_MAPT && otype == DHCPV6_OPT_S46_BR &&
313                                                 olen == sizeof(struct in6_addr)) {
314                                         inet_ntop(AF_INET6, odata, buf6, sizeof(buf6));
315                                         fprintf(fp, "br=%s,", buf6);
316                                 } else if (state == STATE_S46_MAPT && otype == DHCPV6_OPT_S46_DMR &&
317                                                 olen >= sizeof(struct dhcpv6_s46_dmr)) {
318                                         struct dhcpv6_s46_dmr *dmr = (struct dhcpv6_s46_dmr*)odata;
319                                         memset(&in6, 0, sizeof(in6));
320                                         size_t prefix6len = dmr->dmr_prefix6_len;
321                                         prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
322
323                                         if (prefix6len > sizeof(in6) ||
324                                             olen < sizeof(struct dhcpv6_s46_dmr) + prefix6len)
325                                                 continue;
326
327                                         memcpy(&in6, dmr->dmr_ipv6_prefix, prefix6len);
328                                         inet_ntop(AF_INET6, &in6, buf6, sizeof(buf6));
329                                         fprintf(fp, "dmr=%s/%d,", buf6, dmr->dmr_prefix6_len);
330                                 }
331                         }
332
333                         fputc(' ', fp);
334                 } else if (state == STATE_S46_LW && otype == DHCPV6_OPT_S46_V4V6BIND &&
335                                 olen >= sizeof(struct dhcpv6_s46_v4v6bind)) {
336                         char buf4[INET_ADDRSTRLEN];
337                         char buf6[INET6_ADDRSTRLEN];
338                         struct in6_addr in6 = IN6ADDR_ANY_INIT;
339
340                         size_t prefix6len = bind->bindprefix6_len;
341                         prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
342
343                         if (prefix6len > sizeof(in6) ||
344                             olen < sizeof(struct dhcpv6_s46_v4v6bind) + prefix6len)
345                                 continue;
346
347                         memcpy(&in6, bind->bind_ipv6_prefix, prefix6len);
348
349                         inet_ntop(AF_INET, &bind->ipv4_address, buf4, sizeof(buf4));
350                         inet_ntop(AF_INET6, &in6, buf6, sizeof(buf6));
351
352                         fprintf(fp, "type=%s,prefix4len=32,prefix6len=%d,ipv4prefix=%s,ipv6prefix=%s,",
353                                         type, bind->bindprefix6_len, buf4, buf6);
354
355                         s46_to_env_portparams(&bind->bind_ipv6_prefix[prefix6len],
356                                         olen - sizeof(*bind) - prefix6len, fp);
357
358                         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
359                                 if (otype == DHCPV6_OPT_S46_BR && olen == sizeof(struct in6_addr)) {
360                                         inet_ntop(AF_INET6, odata, buf6, sizeof(buf6));
361                                         fprintf(fp, "br=%s,", buf6);
362                                 }
363                         }
364
365                         fputc(' ', fp);
366                 }
367         }
368
369         fclose(fp);
370         putenv(str);
371 }
372
373
374 void script_call(const char *status, int delay, bool resume)
375 {
376         time_t now = odhcp6c_get_milli_time() / 1000;
377         bool running_script = false;
378
379         if (running) {
380                 kill(running, SIGTERM);
381                 delay -= now - started;
382                 running_script = true;
383         }
384
385         if (resume || !running_script || !action[0])
386                 strncpy(action, status, sizeof(action) - 1);
387
388         pid_t pid = fork();
389         if (pid > 0) {
390                 running = pid;
391                 started = now;
392
393                 if (!resume)
394                         action[0] = 0;
395         } else if (pid == 0) {
396                 size_t dns_len, search_len, custom_len, sntp_ip_len, ntp_ip_len, ntp_dns_len;
397                 size_t sip_ip_len, sip_fqdn_len, aftr_name_len, cer_len, addr_len;
398                 size_t s46_mapt_len, s46_mape_len, s46_lw_len, passthru_len;
399
400                 signal(SIGTERM, SIG_DFL);
401                 if (delay > 0) {
402                         sleep(delay);
403                         odhcp6c_expire();
404                 }
405
406                 struct in6_addr *addr = odhcp6c_get_state(STATE_SERVER_ADDR, &addr_len);
407                 struct in6_addr *dns = odhcp6c_get_state(STATE_DNS, &dns_len);
408                 uint8_t *search = odhcp6c_get_state(STATE_SEARCH, &search_len);
409                 uint8_t *custom = odhcp6c_get_state(STATE_CUSTOM_OPTS, &custom_len);
410                 struct in6_addr *sntp = odhcp6c_get_state(STATE_SNTP_IP, &sntp_ip_len);
411                 struct in6_addr *ntp = odhcp6c_get_state(STATE_NTP_IP, &ntp_ip_len);
412                 uint8_t *ntp_dns = odhcp6c_get_state(STATE_NTP_FQDN, &ntp_dns_len);
413                 struct in6_addr *sip = odhcp6c_get_state(STATE_SIP_IP, &sip_ip_len);
414                 uint8_t *sip_fqdn = odhcp6c_get_state(STATE_SIP_FQDN, &sip_fqdn_len);
415                 uint8_t *aftr_name = odhcp6c_get_state(STATE_AFTR_NAME, &aftr_name_len);
416                 struct in6_addr *cer = odhcp6c_get_state(STATE_CER, &cer_len);
417                 uint8_t *s46_mapt = odhcp6c_get_state(STATE_S46_MAPT, &s46_mapt_len);
418                 uint8_t *s46_mape = odhcp6c_get_state(STATE_S46_MAPE, &s46_mape_len);
419                 uint8_t *s46_lw = odhcp6c_get_state(STATE_S46_LW, &s46_lw_len);
420                 uint8_t *passthru = odhcp6c_get_state(STATE_PASSTHRU, &passthru_len);
421
422                 size_t prefix_len, address_len, ra_pref_len,
423                         ra_route_len, ra_dns_len, ra_search_len;
424                 uint8_t *prefix = odhcp6c_get_state(STATE_IA_PD, &prefix_len);
425                 uint8_t *address = odhcp6c_get_state(STATE_IA_NA, &address_len);
426                 uint8_t *ra_pref = odhcp6c_get_state(STATE_RA_PREFIX, &ra_pref_len);
427                 uint8_t *ra_route = odhcp6c_get_state(STATE_RA_ROUTE, &ra_route_len);
428                 uint8_t *ra_dns = odhcp6c_get_state(STATE_RA_DNS, &ra_dns_len);
429                 uint8_t *ra_search = odhcp6c_get_state(STATE_RA_SEARCH, &ra_search_len);
430
431                 ipv6_to_env("SERVER", addr, addr_len / sizeof(*addr));
432                 ipv6_to_env("RDNSS", dns, dns_len / sizeof(*dns));
433                 ipv6_to_env("SNTP_IP", sntp, sntp_ip_len / sizeof(*sntp));
434                 ipv6_to_env("NTP_IP", ntp, ntp_ip_len / sizeof(*ntp));
435                 fqdn_to_env("NTP_FQDN", ntp_dns, ntp_dns_len);
436                 ipv6_to_env("SIP_IP", sip, sip_ip_len / sizeof(*sip));
437                 fqdn_to_env("DOMAINS", search, search_len);
438                 fqdn_to_env("SIP_DOMAIN", sip_fqdn, sip_fqdn_len);
439                 fqdn_to_env("AFTR", aftr_name, aftr_name_len);
440                 ipv6_to_env("CER", cer, cer_len / sizeof(*cer));
441                 s46_to_env(STATE_S46_MAPE, s46_mape, s46_mape_len);
442                 s46_to_env(STATE_S46_MAPT, s46_mapt, s46_mapt_len);
443                 s46_to_env(STATE_S46_LW, s46_lw, s46_lw_len);
444                 bin_to_env(custom, custom_len);
445
446                 if (odhcp6c_is_bound()) {
447                         entry_to_env("PREFIXES", prefix, prefix_len, ENTRY_PREFIX);
448                         entry_to_env("ADDRESSES", address, address_len, ENTRY_ADDRESS);
449                 }
450
451                 entry_to_env("RA_ADDRESSES", ra_pref, ra_pref_len, ENTRY_ADDRESS);
452                 entry_to_env("RA_ROUTES", ra_route, ra_route_len, ENTRY_ROUTE);
453                 entry_to_env("RA_DNS", ra_dns, ra_dns_len, ENTRY_HOST);
454                 search_to_env("RA_DOMAINS", ra_search, ra_search_len);
455
456                 int_to_env("RA_HOPLIMIT", ra_conf_hoplimit(0));
457                 int_to_env("RA_MTU", ra_conf_mtu(0));
458                 int_to_env("RA_REACHABLE", ra_conf_reachable(0));
459                 int_to_env("RA_RETRANSMIT", ra_conf_retransmit(0));
460
461                 char *buf = malloc(10 + passthru_len * 2);
462                 strncpy(buf, "PASSTHRU=", 10);
463                 script_hexlify(&buf[9], passthru, passthru_len);
464                 putenv(buf);
465
466                 execv(argv[0], argv);
467                 _exit(128);
468         }
469 }