Fix forgotten license comments
[oweals/busybox.git] / networking / udhcp / files.c
1 /* vi: set sw=4 ts=4: */
2 /*
3  * files.c -- DHCP server file manipulation *
4  * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
5  *
6  * Licensed under GPLv2, see file LICENSE in this tarball for details.
7  */
8
9 #include <netinet/ether.h>
10
11 #include "common.h"
12 #include "dhcpd.h"
13 #include "options.h"
14
15
16 /* on these functions, make sure your datatype matches */
17 static int read_ip(const char *line, void *arg)
18 {
19         len_and_sockaddr *lsa;
20
21         lsa = host_and_af2sockaddr(line, 0, AF_INET);
22         if (!lsa)
23                 return 0;
24         *(uint32_t*)arg = lsa->u.sin.sin_addr.s_addr;
25         free(lsa);
26         return 1;
27 }
28
29 static int read_mac(const char *line, void *arg)
30 {
31         struct ether_addr *temp_ether_addr;
32
33         temp_ether_addr = ether_aton_r(line, (struct ether_addr *)arg);
34         if (temp_ether_addr == NULL)
35                 return 0;
36         return 1;
37 }
38
39
40 static int read_str(const char *line, void *arg)
41 {
42         char **dest = arg;
43
44         free(*dest);
45         *dest = xstrdup(line);
46         return 1;
47 }
48
49
50 static int read_u32(const char *line, void *arg)
51 {
52         *(uint32_t*)arg = bb_strtou32(line, NULL, 10);
53         return errno == 0;
54 }
55
56
57 static int read_yn(const char *line, void *arg)
58 {
59         char *dest = arg;
60
61         if (!strcasecmp("yes", line)) {
62                 *dest = 1;
63                 return 1;
64         }
65         if (!strcasecmp("no", line)) {
66                 *dest = 0;
67                 return 1;
68         }
69         return 0;
70 }
71
72
73 /* find option 'code' in opt_list */
74 struct option_set* FAST_FUNC find_option(struct option_set *opt_list, uint8_t code)
75 {
76         while (opt_list && opt_list->data[OPT_CODE] < code)
77                 opt_list = opt_list->next;
78
79         if (opt_list && opt_list->data[OPT_CODE] == code)
80                 return opt_list;
81         return NULL;
82 }
83
84
85 /* add an option to the opt_list */
86 static void attach_option(struct option_set **opt_list,
87                 const struct dhcp_option *option, char *buffer, int length)
88 {
89         struct option_set *existing, *new, **curr;
90
91         existing = find_option(*opt_list, option->code);
92         if (!existing) {
93                 DEBUG("Attaching option %02x to list", option->code);
94
95 #if ENABLE_FEATURE_UDHCP_RFC3397
96                 if ((option->flags & TYPE_MASK) == OPTION_STR1035)
97                         /* reuse buffer and length for RFC1035-formatted string */
98                         buffer = (char *)dname_enc(NULL, 0, buffer, &length);
99 #endif
100
101                 /* make a new option */
102                 new = xmalloc(sizeof(*new));
103                 new->data = xmalloc(length + 2);
104                 new->data[OPT_CODE] = option->code;
105                 new->data[OPT_LEN] = length;
106                 memcpy(new->data + 2, buffer, length);
107
108                 curr = opt_list;
109                 while (*curr && (*curr)->data[OPT_CODE] < option->code)
110                         curr = &(*curr)->next;
111
112                 new->next = *curr;
113                 *curr = new;
114 #if ENABLE_FEATURE_UDHCP_RFC3397
115                 if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
116                         free(buffer);
117 #endif
118                 return;
119         }
120
121         /* add it to an existing option */
122         DEBUG("Attaching option %02x to existing member of list", option->code);
123         if (option->flags & OPTION_LIST) {
124 #if ENABLE_FEATURE_UDHCP_RFC3397
125                 if ((option->flags & TYPE_MASK) == OPTION_STR1035)
126                         /* reuse buffer and length for RFC1035-formatted string */
127                         buffer = (char *)dname_enc(existing->data + 2,
128                                         existing->data[OPT_LEN], buffer, &length);
129 #endif
130                 if (existing->data[OPT_LEN] + length <= 255) {
131                         existing->data = xrealloc(existing->data,
132                                         existing->data[OPT_LEN] + length + 3);
133                         if ((option->flags & TYPE_MASK) == OPTION_STRING) {
134                                 /* ' ' can bring us to 256 - bad */
135                                 if (existing->data[OPT_LEN] + length >= 255)
136                                         return;
137                                 /* add space separator between STRING options in a list */
138                                 existing->data[existing->data[OPT_LEN] + 2] = ' ';
139                                 existing->data[OPT_LEN]++;
140                         }
141                         memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
142                         existing->data[OPT_LEN] += length;
143                 } /* else, ignore the data, we could put this in a second option in the future */
144 #if ENABLE_FEATURE_UDHCP_RFC3397
145                 if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
146                         free(buffer);
147 #endif
148         } /* else, ignore the new data */
149 }
150
151
152 /* read a dhcp option and add it to opt_list */
153 static int read_opt(const char *const_line, void *arg)
154 {
155         struct option_set **opt_list = arg;
156         char *opt, *val, *endptr;
157         char *line;
158         const struct dhcp_option *option;
159         int retval, length, idx;
160         char buffer[8] ALIGNED(4);
161         uint16_t *result_u16 = (uint16_t *) buffer;
162         uint32_t *result_u32 = (uint32_t *) buffer;
163
164         /* Cheat, the only const line we'll actually get is "" */
165         line = (char *) const_line;
166         opt = strtok(line, " \t=");
167         if (!opt)
168                 return 0;
169
170         idx = index_in_strings(dhcp_option_strings, opt); /* NB: was strcasecmp! */
171         if (idx < 0)
172                 return 0;
173         option = &dhcp_options[idx];
174
175         retval = 0;
176         do {
177                 val = strtok(NULL, ", \t");
178                 if (!val) break;
179                 length = dhcp_option_lengths[option->flags & TYPE_MASK];
180                 retval = 0;
181                 opt = buffer; /* new meaning for variable opt */
182                 switch (option->flags & TYPE_MASK) {
183                 case OPTION_IP:
184                         retval = read_ip(val, buffer);
185                         break;
186                 case OPTION_IP_PAIR:
187                         retval = read_ip(val, buffer);
188                         val = strtok(NULL, ", \t/-");
189                         if (!val)
190                                 retval = 0;
191                         if (retval)
192                                 retval = read_ip(val, buffer + 4);
193                         break;
194                 case OPTION_STRING:
195 #if ENABLE_FEATURE_UDHCP_RFC3397
196                 case OPTION_STR1035:
197 #endif
198                         length = strlen(val);
199                         if (length > 0) {
200                                 if (length > 254) length = 254;
201                                 opt = val;
202                                 retval = 1;
203                         }
204                         break;
205                 case OPTION_BOOLEAN:
206                         retval = read_yn(val, buffer);
207                         break;
208                 case OPTION_U8:
209                         buffer[0] = strtoul(val, &endptr, 0);
210                         retval = (endptr[0] == '\0');
211                         break;
212                 /* htonX are macros in older libc's, using temp var
213                  * in code below for safety */
214                 /* TODO: use bb_strtoX? */
215                 case OPTION_U16: {
216                         unsigned long tmp = strtoul(val, &endptr, 0);
217                         *result_u16 = htons(tmp);
218                         retval = (endptr[0] == '\0' /*&& tmp < 0x10000*/);
219                         break;
220                 }
221                 case OPTION_S16: {
222                         long tmp = strtol(val, &endptr, 0);
223                         *result_u16 = htons(tmp);
224                         retval = (endptr[0] == '\0');
225                         break;
226                 }
227                 case OPTION_U32: {
228                         unsigned long tmp = strtoul(val, &endptr, 0);
229                         *result_u32 = htonl(tmp);
230                         retval = (endptr[0] == '\0');
231                         break;
232                 }
233                 case OPTION_S32: {
234                         long tmp = strtol(val, &endptr, 0);
235                         *result_u32 = htonl(tmp);
236                         retval = (endptr[0] == '\0');
237                         break;
238                 }
239                 default:
240                         break;
241                 }
242                 if (retval)
243                         attach_option(opt_list, option, opt, length);
244         } while (retval && option->flags & OPTION_LIST);
245         return retval;
246 }
247
248 static int read_staticlease(const char *const_line, void *arg)
249 {
250         char *line;
251         char *mac_string;
252         char *ip_string;
253         uint8_t *mac_bytes;
254         uint32_t *ip;
255
256         /* Allocate memory for addresses */
257         mac_bytes = xmalloc(sizeof(unsigned char) * 8);
258         ip = xmalloc(sizeof(uint32_t));
259
260         /* Read mac */
261         line = (char *) const_line;
262         mac_string = strtok(line, " \t");
263         read_mac(mac_string, mac_bytes);
264
265         /* Read ip */
266         ip_string = strtok(NULL, " \t");
267         read_ip(ip_string, ip);
268
269         addStaticLease(arg, mac_bytes, ip);
270
271         if (ENABLE_UDHCP_DEBUG) printStaticLeases(arg);
272
273         return 1;
274 }
275
276
277 struct config_keyword {
278         const char *keyword;
279         int (*handler)(const char *line, void *var);
280         void *var;
281         const char *def;
282 };
283
284 static const struct config_keyword keywords[] = {
285         /* keyword       handler   variable address               default */
286         {"start",        read_ip,  &(server_config.start_ip),     "192.168.0.20"},
287         {"end",          read_ip,  &(server_config.end_ip),       "192.168.0.254"},
288         {"interface",    read_str, &(server_config.interface),    "eth0"},
289         /* Avoid "max_leases value not sane" warning by setting default
290          * to default_end_ip - default_start_ip + 1: */
291         {"max_leases",   read_u32, &(server_config.max_leases),   "235"},
292         {"remaining",    read_yn,  &(server_config.remaining),    "yes"},
293         {"auto_time",    read_u32, &(server_config.auto_time),    "7200"},
294         {"decline_time", read_u32, &(server_config.decline_time), "3600"},
295         {"conflict_time",read_u32, &(server_config.conflict_time),"3600"},
296         {"offer_time",   read_u32, &(server_config.offer_time),   "60"},
297         {"min_lease",    read_u32, &(server_config.min_lease),    "60"},
298         {"lease_file",   read_str, &(server_config.lease_file),   LEASES_FILE},
299         {"pidfile",      read_str, &(server_config.pidfile),      "/var/run/udhcpd.pid"},
300         {"siaddr",       read_ip,  &(server_config.siaddr),       "0.0.0.0"},
301         /* keywords with no defaults must be last! */
302         {"option",       read_opt, &(server_config.options),      ""},
303         {"opt",          read_opt, &(server_config.options),      ""},
304         {"notify_file",  read_str, &(server_config.notify_file),  ""},
305         {"sname",        read_str, &(server_config.sname),        ""},
306         {"boot_file",    read_str, &(server_config.boot_file),    ""},
307         {"static_lease", read_staticlease, &(server_config.static_leases), ""},
308         /* ADDME: static lease */
309 };
310 enum { KWS_WITH_DEFAULTS = ARRAY_SIZE(keywords) - 6 };
311
312 void FAST_FUNC read_config(const char *file)
313 {
314         parser_t *parser;
315         const struct config_keyword *k;
316         unsigned i;
317         char *token[2];
318
319         for (i = 0; i < KWS_WITH_DEFAULTS; i++)
320                 keywords[i].handler(keywords[i].def, keywords[i].var);
321
322         parser = config_open(file);
323         while (config_read(parser, token, 2, 2, "# \t", PARSE_NORMAL)) {
324                 for (k = keywords, i = 0; i < ARRAY_SIZE(keywords); k++, i++) {
325                         if (!strcasecmp(token[0], k->keyword)) {
326                                 if (!k->handler(token[1], k->var)) {
327                                         bb_error_msg("can't parse line %u in %s",
328                                                         parser->lineno, file);
329                                         /* reset back to the default value */
330                                         k->handler(k->def, k->var);
331                                 }
332                                 break;
333                         }
334                 }
335         }
336         config_close(parser);
337
338         server_config.start_ip = ntohl(server_config.start_ip);
339         server_config.end_ip = ntohl(server_config.end_ip);
340 }
341
342
343 void FAST_FUNC write_leases(void)
344 {
345         int fp;
346         unsigned i;
347         time_t curr = time(0);
348         unsigned long tmp_time;
349
350         fp = open_or_warn(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC);
351         if (fp < 0) {
352                 return;
353         }
354
355         for (i = 0; i < server_config.max_leases; i++) {
356                 if (leases[i].yiaddr != 0) {
357
358                         /* screw with the time in the struct, for easier writing */
359                         tmp_time = leases[i].expires;
360
361                         if (server_config.remaining) {
362                                 if (lease_expired(&(leases[i])))
363                                         leases[i].expires = 0;
364                                 else leases[i].expires -= curr;
365                         } /* else stick with the time we got */
366                         leases[i].expires = htonl(leases[i].expires);
367                         // FIXME: error check??
368                         full_write(fp, &leases[i], sizeof(leases[i]));
369
370                         /* then restore it when done */
371                         leases[i].expires = tmp_time;
372                 }
373         }
374         close(fp);
375
376         if (server_config.notify_file) {
377 // TODO: vfork-based child creation
378                 char *cmd = xasprintf("%s %s", server_config.notify_file, server_config.lease_file);
379                 system(cmd);
380                 free(cmd);
381         }
382 }
383
384
385 void FAST_FUNC read_leases(const char *file)
386 {
387         int fp;
388         unsigned i;
389         struct dhcpOfferedAddr lease;
390
391         fp = open_or_warn(file, O_RDONLY);
392         if (fp < 0) {
393                 return;
394         }
395
396         i = 0;
397         while (i < server_config.max_leases
398          && full_read(fp, &lease, sizeof(lease)) == sizeof(lease)
399         ) {
400                 /* ADDME: is it a static lease */
401                 uint32_t y = ntohl(lease.yiaddr);
402                 if (y >= server_config.start_ip && y <= server_config.end_ip) {
403                         lease.expires = ntohl(lease.expires);
404                         if (!server_config.remaining)
405                                 lease.expires -= time(NULL);
406                         if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
407                                 bb_error_msg("too many leases while loading %s", file);
408                                 break;
409                         }
410                         i++;
411                 }
412         }
413         DEBUG("Read %d leases", i);
414         close(fp);
415 }