/* vi: set sw=4 ts=4: */ /* * files.c -- DHCP server file manipulation * * Rewrite by Russ Dill July 2001 */ #include #include "common.h" #include "dhcpd.h" #include "options.h" /* on these functions, make sure your datatype matches */ static int read_ip(const char *line, void *arg) { len_and_sockaddr *lsa; lsa = host_and_af2sockaddr(line, 0, AF_INET); if (!lsa) return 0; *(uint32_t*)arg = lsa->u.sin.sin_addr.s_addr; free(lsa); return 1; } static int read_mac(const char *line, void *arg) { uint8_t *mac_bytes = arg; struct ether_addr *temp_ether_addr; temp_ether_addr = ether_aton(line); if (temp_ether_addr == NULL) return 0; memcpy(mac_bytes, temp_ether_addr, 6); return 1; } static int read_str(const char *line, void *arg) { char **dest = arg; free(*dest); *dest = xstrdup(line); return 1; } static int read_u32(const char *line, void *arg) { *(uint32_t*)arg = bb_strtou32(line, NULL, 10); return errno == 0; } static int read_yn(const char *line, void *arg) { char *dest = arg; if (!strcasecmp("yes", line)) { *dest = 1; return 1; } if (!strcasecmp("no", line)) { *dest = 0; return 1; } return 0; } /* find option 'code' in opt_list */ struct option_set *find_option(struct option_set *opt_list, uint8_t code) { while (opt_list && opt_list->data[OPT_CODE] < code) opt_list = opt_list->next; if (opt_list && opt_list->data[OPT_CODE] == code) return opt_list; return NULL; } /* add an option to the opt_list */ static void attach_option(struct option_set **opt_list, const struct dhcp_option *option, char *buffer, int length) { struct option_set *existing, *new, **curr; existing = find_option(*opt_list, option->code); if (!existing) { DEBUG("Attaching option %02x to list", option->code); #if ENABLE_FEATURE_RFC3397 if ((option->flags & TYPE_MASK) == OPTION_STR1035) /* reuse buffer and length for RFC1035-formatted string */ buffer = dname_enc(NULL, 0, buffer, &length); #endif /* make a new option */ new = xmalloc(sizeof(*new)); new->data = xmalloc(length + 2); new->data[OPT_CODE] = option->code; new->data[OPT_LEN] = length; memcpy(new->data + 2, buffer, length); curr = opt_list; while (*curr && (*curr)->data[OPT_CODE] < option->code) curr = &(*curr)->next; new->next = *curr; *curr = new; #if ENABLE_FEATURE_RFC3397 if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL) free(buffer); #endif return; } /* add it to an existing option */ DEBUG("Attaching option %02x to existing member of list", option->code); if (option->flags & OPTION_LIST) { #if ENABLE_FEATURE_RFC3397 if ((option->flags & TYPE_MASK) == OPTION_STR1035) /* reuse buffer and length for RFC1035-formatted string */ buffer = dname_enc(existing->data + 2, existing->data[OPT_LEN], buffer, &length); #endif if (existing->data[OPT_LEN] + length <= 255) { existing->data = xrealloc(existing->data, existing->data[OPT_LEN] + length + 3); if ((option->flags & TYPE_MASK) == OPTION_STRING) { /* ' ' can bring us to 256 - bad */ if (existing->data[OPT_LEN] + length >= 255) return; /* add space separator between STRING options in a list */ existing->data[existing->data[OPT_LEN] + 2] = ' '; existing->data[OPT_LEN]++; } memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length); existing->data[OPT_LEN] += length; } /* else, ignore the data, we could put this in a second option in the future */ #if ENABLE_FEATURE_RFC3397 if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL) free(buffer); #endif } /* else, ignore the new data */ } /* read a dhcp option and add it to opt_list */ static int read_opt(const char *const_line, void *arg) { struct option_set **opt_list = arg; char *opt, *val, *endptr; char *line; const struct dhcp_option *option; int retval, length, idx; char buffer[8] __attribute__((aligned(4))); uint16_t *result_u16 = (uint16_t *) buffer; uint32_t *result_u32 = (uint32_t *) buffer; /* Cheat, the only const line we'll actually get is "" */ line = (char *) const_line; opt = strtok(line, " \t="); if (!opt) return 0; idx = index_in_strings(dhcp_option_strings, opt); /* NB: was strcasecmp! */ if (idx < 0) return 0; option = &dhcp_options[idx]; retval = 0; do { val = strtok(NULL, ", \t"); if (!val) break; length = dhcp_option_lengths[option->flags & TYPE_MASK]; retval = 0; opt = buffer; /* new meaning for variable opt */ switch (option->flags & TYPE_MASK) { case OPTION_IP: retval = read_ip(val, buffer); break; case OPTION_IP_PAIR: retval = read_ip(val, buffer); val = strtok(NULL, ", \t/-"); if (!val) retval = 0; if (retval) retval = read_ip(val, buffer + 4); break; case OPTION_STRING: #if ENABLE_FEATURE_RFC3397 case OPTION_STR1035: #endif length = strlen(val); if (length > 0) { if (length > 254) length = 254; opt = val; retval = 1; } break; case OPTION_BOOLEAN: retval = read_yn(val, buffer); break; case OPTION_U8: buffer[0] = strtoul(val, &endptr, 0); retval = (endptr[0] == '\0'); break; /* htonX are macros in older libc's, using temp var * in code below for safety */ /* TODO: use bb_strtoX? */ case OPTION_U16: { unsigned long tmp = strtoul(val, &endptr, 0); *result_u16 = htons(tmp); retval = (endptr[0] == '\0' /*&& tmp < 0x10000*/); break; } case OPTION_S16: { long tmp = strtol(val, &endptr, 0); *result_u16 = htons(tmp); retval = (endptr[0] == '\0'); break; } case OPTION_U32: { unsigned long tmp = strtoul(val, &endptr, 0); *result_u32 = htonl(tmp); retval = (endptr[0] == '\0'); break; } case OPTION_S32: { long tmp = strtol(val, &endptr, 0); *result_u32 = htonl(tmp); retval = (endptr[0] == '\0'); break; } default: break; } if (retval) attach_option(opt_list, option, opt, length); } while (retval && option->flags & OPTION_LIST); return retval; } static int read_staticlease(const char *const_line, void *arg) { char *line; char *mac_string; char *ip_string; uint8_t *mac_bytes; uint32_t *ip; /* Allocate memory for addresses */ mac_bytes = xmalloc(sizeof(unsigned char) * 8); ip = xmalloc(sizeof(uint32_t)); /* Read mac */ line = (char *) const_line; mac_string = strtok(line, " \t"); read_mac(mac_string, mac_bytes); /* Read ip */ ip_string = strtok(NULL, " \t"); read_ip(ip_string, ip); addStaticLease(arg, mac_bytes, ip); if (ENABLE_FEATURE_UDHCP_DEBUG) printStaticLeases(arg); return 1; } struct config_keyword { const char *keyword; int (*handler)(const char *line, void *var); void *var; const char *def; }; static const struct config_keyword keywords[] = { /* keyword handler variable address default */ {"start", read_ip, &(server_config.start_ip), "192.168.0.20"}, {"end", read_ip, &(server_config.end_ip), "192.168.0.254"}, {"interface", read_str, &(server_config.interface), "eth0"}, /* Avoid "max_leases value not sane" warning by setting default * to default_end_ip - default_start_ip + 1: */ {"max_leases", read_u32, &(server_config.max_leases), "235"}, {"remaining", read_yn, &(server_config.remaining), "yes"}, {"auto_time", read_u32, &(server_config.auto_time), "7200"}, {"decline_time", read_u32, &(server_config.decline_time), "3600"}, {"conflict_time",read_u32, &(server_config.conflict_time),"3600"}, {"offer_time", read_u32, &(server_config.offer_time), "60"}, {"min_lease", read_u32, &(server_config.min_lease), "60"}, {"lease_file", read_str, &(server_config.lease_file), LEASES_FILE}, {"pidfile", read_str, &(server_config.pidfile), "/var/run/udhcpd.pid"}, {"siaddr", read_ip, &(server_config.siaddr), "0.0.0.0"}, /* keywords with no defaults must be last! */ {"option", read_opt, &(server_config.options), ""}, {"opt", read_opt, &(server_config.options), ""}, {"notify_file", read_str, &(server_config.notify_file), ""}, {"sname", read_str, &(server_config.sname), ""}, {"boot_file", read_str, &(server_config.boot_file), ""}, {"static_lease", read_staticlease, &(server_config.static_leases), ""}, /* ADDME: static lease */ }; enum { KWS_WITH_DEFAULTS = ARRAY_SIZE(keywords) - 6 }; /* * Domain names may have 254 chars, and string options can be 254 * chars long. However, 80 bytes will be enough for most, and won't * hog up memory. If you have a special application, change it */ #define READ_CONFIG_BUF_SIZE 80 void read_config(const char *file) { FILE *in; char buffer[READ_CONFIG_BUF_SIZE], *token, *line; int i, lineno; for (i = 0; i < KWS_WITH_DEFAULTS; i++) keywords[i].handler(keywords[i].def, keywords[i].var); in = fopen_or_warn(file, "r"); if (!in) return; lineno = 0; while (fgets(buffer, READ_CONFIG_BUF_SIZE, in)) { lineno++; /* *strchrnul(buffer, '\n') = '\0'; - trim() will do it */ *strchrnul(buffer, '#') = '\0'; token = strtok(buffer, " \t"); if (!token) continue; line = strtok(NULL, ""); if (!line) continue; trim(line); /* remove leading/trailing whitespace */ for (i = 0; i < ARRAY_SIZE(keywords); i++) { if (!strcasecmp(token, keywords[i].keyword)) { if (!keywords[i].handler(line, keywords[i].var)) { bb_error_msg("can't parse line %d in %s at '%s'", lineno, file, line); /* reset back to the default value */ keywords[i].handler(keywords[i].def, keywords[i].var); } break; } } } fclose(in); server_config.start_ip = ntohl(server_config.start_ip); server_config.end_ip = ntohl(server_config.end_ip); } void write_leases(void) { int fp; unsigned i; time_t curr = time(0); unsigned long tmp_time; fp = open_or_warn(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC); if (fp < 0) { return; } for (i = 0; i < server_config.max_leases; i++) { if (leases[i].yiaddr != 0) { /* screw with the time in the struct, for easier writing */ tmp_time = leases[i].expires; if (server_config.remaining) { if (lease_expired(&(leases[i]))) leases[i].expires = 0; else leases[i].expires -= curr; } /* else stick with the time we got */ leases[i].expires = htonl(leases[i].expires); // FIXME: error check?? full_write(fp, &leases[i], sizeof(leases[i])); /* then restore it when done */ leases[i].expires = tmp_time; } } close(fp); if (server_config.notify_file) { // TODO: vfork-based child creation char *cmd = xasprintf("%s %s", server_config.notify_file, server_config.lease_file); system(cmd); free(cmd); } } void read_leases(const char *file) { int fp; unsigned i; struct dhcpOfferedAddr lease; fp = open_or_warn(file, O_RDONLY); if (fp < 0) { return; } i = 0; while (i < server_config.max_leases && full_read(fp, &lease, sizeof(lease)) == sizeof(lease) ) { /* ADDME: is it a static lease */ uint32_t y = ntohl(lease.yiaddr); if (y >= server_config.start_ip && y <= server_config.end_ip) { lease.expires = ntohl(lease.expires); if (!server_config.remaining) lease.expires -= time(NULL); if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) { bb_error_msg("too many leases while loading %s", file); break; } i++; } } DEBUG("Read %d leases", i); close(fp); }