/* vi: set sw=4 ts=4: */ /* * files.c -- DHCP server file manipulation * * Rewrite by Russ Dill July 2001 * * Licensed under GPLv2, see file LICENSE in this tarball for details. */ #include #include "common.h" #include "dhcpd.h" #if BB_LITTLE_ENDIAN static inline uint64_t hton64(uint64_t v) { return (((uint64_t)htonl(v)) << 32) | htonl(v >> 32); } #else #define hton64(v) (v) #endif #define ntoh64(v) hton64(v) /* on these functions, make sure your datatype matches */ static int FAST_FUNC read_nip(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 FAST_FUNC read_str(const char *line, void *arg) { char **dest = arg; free(*dest); *dest = xstrdup(line); return 1; } static int FAST_FUNC 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) == 0) { *dest = 1; return 1; } if (strcasecmp("no", line) == 0) { *dest = 0; return 1; } return 0; } /* find option 'code' in opt_list */ struct option_set* FAST_FUNC 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 NOINLINE void attach_option( struct option_set **opt_list, const struct dhcp_option *option, char *buffer, int length) { struct option_set *existing, *new, **curr; #if ENABLE_FEATURE_UDHCP_RFC3397 char *allocated = NULL; #endif existing = find_option(*opt_list, option->code); if (!existing) { log2("Attaching option %02x to list", option->code); #if ENABLE_FEATURE_UDHCP_RFC3397 if ((option->flags & OPTION_TYPE_MASK) == OPTION_STR1035) { /* reuse buffer and length for RFC1035-formatted string */ allocated = buffer = (char *)dname_enc(NULL, 0, buffer, &length); } #endif /* make a new option */ new = xmalloc(sizeof(*new)); new->data = xmalloc(length + OPT_DATA); new->data[OPT_CODE] = option->code; new->data[OPT_LEN] = length; memcpy(new->data + OPT_DATA, buffer, length); curr = opt_list; while (*curr && (*curr)->data[OPT_CODE] < option->code) curr = &(*curr)->next; new->next = *curr; *curr = new; goto ret; } if (option->flags & OPTION_LIST) { unsigned old_len; /* add it to an existing option */ log1("Attaching option %02x to existing member of list", option->code); old_len = existing->data[OPT_LEN]; #if ENABLE_FEATURE_UDHCP_RFC3397 if ((option->flags & OPTION_TYPE_MASK) == OPTION_STR1035) { /* reuse buffer and length for RFC1035-formatted string */ allocated = buffer = (char *)dname_enc(existing->data + OPT_DATA, old_len, buffer, &length); } #endif if (old_len + length < 255) { /* actually 255 is ok too, but adding a space can overlow it */ existing->data = xrealloc(existing->data, OPT_DATA + 1 + old_len + length); if ((option->flags & OPTION_TYPE_MASK) == OPTION_STRING) { /* add space separator between STRING options in a list */ existing->data[OPT_DATA + old_len] = ' '; old_len++; } memcpy(existing->data + OPT_DATA + old_len, buffer, length); existing->data[OPT_LEN] = old_len + length; } /* else, ignore the data, we could put this in a second option in the future */ } /* else, ignore the new data */ ret: ; #if ENABLE_FEATURE_UDHCP_RFC3397 free(allocated); #endif } /* read a dhcp option and add it to opt_list */ int FAST_FUNC udhcp_str2optset(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] ALIGNED(4); uint16_t *result_u16 = (uint16_t *) buffer; uint32_t *result_u32 = (uint32_t *) buffer; /* Cheat, the only *const* line possible 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 & OPTION_TYPE_MASK]; retval = 0; opt = buffer; /* new meaning for variable opt */ switch (option->flags & OPTION_TYPE_MASK) { case OPTION_IP: retval = read_nip(val, buffer); break; case OPTION_IP_PAIR: retval = read_nip(val, buffer); val = strtok(NULL, ", \t/-"); if (!val) retval = 0; if (retval) retval = read_nip(val, buffer + 4); break; case OPTION_STRING: #if ENABLE_FEATURE_UDHCP_RFC3397 case OPTION_STR1035: #endif length = strnlen(val, 254); if (length > 0) { 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 FAST_FUNC read_staticlease(const char *const_line, void *arg) { char *line; char *mac_string; char *ip_string; struct ether_addr mac_bytes; /* it's "struct { uint8_t mac[6]; }" */ uint32_t nip; /* Read mac */ line = (char *) const_line; mac_string = strtok_r(line, " \t", &line); if (!mac_string || !ether_aton_r(mac_string, &mac_bytes)) return 0; /* Read ip */ ip_string = strtok_r(NULL, " \t", &line); if (!ip_string || !read_nip(ip_string, &nip)) return 0; add_static_lease(arg, (uint8_t*) &mac_bytes, nip); log_static_leases(arg); return 1; } struct config_keyword { const char *keyword; int (*handler)(const char *line, void *var) FAST_FUNC; void *var; const char *def; }; static const struct config_keyword keywords[] = { /* keyword handler variable address default */ {"start", read_nip, &(server_config.start_ip), "192.168.0.20"}, {"end", read_nip, &(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"}, {"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_sec),"60"}, {"lease_file", read_str, &(server_config.lease_file), LEASES_FILE}, {"pidfile", read_str, &(server_config.pidfile), "/var/run/udhcpd.pid"}, {"siaddr", read_nip, &(server_config.siaddr_nip), "0.0.0.0"}, /* keywords with no defaults must be last! */ {"option", udhcp_str2optset, &(server_config.options), ""}, {"opt", udhcp_str2optset, &(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), ""}, }; enum { KWS_WITH_DEFAULTS = ARRAY_SIZE(keywords) - 6 }; void FAST_FUNC read_config(const char *file) { parser_t *parser; const struct config_keyword *k; unsigned i; char *token[2]; for (i = 0; i < KWS_WITH_DEFAULTS; i++) keywords[i].handler(keywords[i].def, keywords[i].var); parser = config_open(file); while (config_read(parser, token, 2, 2, "# \t", PARSE_NORMAL)) { for (k = keywords, i = 0; i < ARRAY_SIZE(keywords); k++, i++) { if (strcasecmp(token[0], k->keyword) == 0) { if (!k->handler(token[1], k->var)) { bb_error_msg("can't parse line %u in %s", parser->lineno, file); /* reset back to the default value */ k->handler(k->def, k->var); } break; } } } config_close(parser); server_config.start_ip = ntohl(server_config.start_ip); server_config.end_ip = ntohl(server_config.end_ip); } void FAST_FUNC write_leases(void) { int fd; unsigned i; leasetime_t curr; int64_t written_at; fd = open_or_warn(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC); if (fd < 0) return; curr = written_at = time(NULL); written_at = hton64(written_at); full_write(fd, &written_at, sizeof(written_at)); for (i = 0; i < server_config.max_leases; i++) { leasetime_t tmp_time; if (g_leases[i].lease_nip == 0) continue; /* Screw with the time in the struct, for easier writing */ tmp_time = g_leases[i].expires; g_leases[i].expires -= curr; if ((signed_leasetime_t) g_leases[i].expires < 0) g_leases[i].expires = 0; g_leases[i].expires = htonl(g_leases[i].expires); /* No error check. If the file gets truncated, * we lose some leases on restart. Oh well. */ full_write(fd, &g_leases[i], sizeof(g_leases[i])); /* Then restore it when done */ g_leases[i].expires = tmp_time; } close(fd); 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 FAST_FUNC read_leases(const char *file) { struct dyn_lease lease; int64_t written_at, time_passed; int fd; #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1 unsigned i = 0; #endif fd = open_or_warn(file, O_RDONLY); if (fd < 0) return; if (full_read(fd, &written_at, sizeof(written_at)) != sizeof(written_at)) goto ret; written_at = ntoh64(written_at); time_passed = time(NULL) - written_at; /* Strange written_at, or lease file from old version of udhcpd * which had no "written_at" field? */ if ((uint64_t)time_passed > 12 * 60 * 60) goto ret; while (full_read(fd, &lease, sizeof(lease)) == sizeof(lease)) { //FIXME: what if it matches some static lease? uint32_t y = ntohl(lease.lease_nip); if (y >= server_config.start_ip && y <= server_config.end_ip) { signed_leasetime_t expires = ntohl(lease.expires) - (signed_leasetime_t)time_passed; if (expires <= 0) continue; /* NB: add_lease takes "relative time", IOW, * lease duration, not lease deadline. */ if (add_lease(lease.lease_mac, lease.lease_nip, expires, lease.hostname, sizeof(lease.hostname) ) == 0 ) { bb_error_msg("too many leases while loading %s", file); break; } #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1 i++; #endif } } log1("Read %d leases", i); ret: close(fd); }