/* $OpenBSD: clparse.c,v 1.203 2021/02/27 17:44:58 krw Exp $ */ /* Parser for dhclient config and lease files. */ /* * Copyright (c) 1997 The Internet Software Consortium. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of The Internet Software Consortium nor the names * of its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * This software has been written for the Internet Software Consortium * by Ted Lemon in cooperation with Vixie * Enterprises. To learn more about the Internet Software Consortium, * see ``http://www.vix.com/isc''. To learn more about Vixie * Enterprises, see ``http://www.vix.com''. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "dhcp.h" #include "dhcpd.h" #include "dhctoken.h" #include "log.h" void parse_conf_decl(FILE *, char *); int parse_hex_octets(FILE *, unsigned int *, uint8_t **); int parse_domain_list(FILE *, int *, char **); int parse_option_list(FILE *, int *, uint8_t *); int parse_interface(FILE *, char *); int parse_lease(FILE *, struct client_lease **); void parse_lease_decl(FILE *, struct client_lease *); int parse_option(FILE *, int *, struct option_data *); int parse_reject_statement(FILE *); void apply_actions(uint8_t *); void set_default_client_identifier(struct ether_addr *); void set_default_hostname(void); void init_config(void) { struct option_data *option; uint32_t expiry; config = calloc(1, sizeof(*config)); if (config == NULL) fatal("config"); TAILQ_INIT(&config->reject_list); /* Set some defaults. */ config->link_interval = 10; /* secs before going daemon w/o lease */ config->select_interval = 0; /* secs to wait for other OFFERs */ config->retry_interval = 1; /* secs before asking for OFFER */ #ifdef SMALL config->backoff_cutoff = 2; /* max secs between packet retries */ config->reboot_interval = 5; /* secs before giving up on reboot */ config->offer_interval = 10; /* secs to wait for an OFFER */ #else config->backoff_cutoff = 10; /* max secs between packet retries */ config->reboot_interval = 1; /* secs before giving up on reboot */ config->offer_interval = 30; /* secs to wait for an OFFER */ #endif config->initial_interval = 1; /* secs before 1st retry */ /* All leases must supply a subnet mask. Classful defaults are dead, Jim. */ config->required_options[config->required_option_count++] = DHO_SUBNET_MASK; /* * Set default lease length, which will determine default renewal * and rebind times. * * XXX Thus applies to both BOOTP and DHCP leases. * * DHO_DHCP_LEASE_TIME (12 hours == 43200 seconds), */ option = &config->defaults[DHO_DHCP_LEASE_TIME]; option->data = malloc(4); if (option->data == NULL) fatal("default lease length"); config->default_actions[DHO_DHCP_LEASE_TIME] = ACTION_DEFAULT; option->len = 4; expiry = htonl(43200); memcpy(option->data, &expiry, 4); config->requested_options [config->requested_option_count++] = DHO_SUBNET_MASK; config->requested_options [config->requested_option_count++] = DHO_BROADCAST_ADDRESS; config->requested_options [config->requested_option_count++] = DHO_TIME_OFFSET; /* RFC 3442 says CLASSLESS_STATIC_ROUTES must be before ROUTERS! */ config->requested_options [config->requested_option_count++] = DHO_CLASSLESS_STATIC_ROUTES; config->requested_options [config->requested_option_count++] = DHO_ROUTERS; config->requested_options [config->requested_option_count++] = DHO_DOMAIN_NAME; config->requested_options [config->requested_option_count++] = DHO_DOMAIN_SEARCH; config->requested_options [config->requested_option_count++] = DHO_DOMAIN_NAME_SERVERS; config->requested_options [config->requested_option_count++] = DHO_HOST_NAME; config->requested_options [config->requested_option_count++] = DHO_BOOTFILE_NAME; config->requested_options [config->requested_option_count++] = DHO_TFTP_SERVER; } /* * conf-decls :== * * | conf-decl * | conf-decls conf-decl */ void read_conf(char *name, uint8_t *actions, struct ether_addr *hwaddr) { FILE *cfile; int token; init_config(); if (path_dhclient_conf != NULL) { cfile = fopen(path_dhclient_conf, "r"); if (cfile == NULL) fatal("fopen(%s)", path_dhclient_conf); new_parse(path_dhclient_conf); for (;;) { token = peek_token(NULL, cfile); if (token == EOF) break; parse_conf_decl(cfile, name); } fclose(cfile); } set_default_client_identifier(hwaddr); set_default_hostname(); apply_actions(actions); } /* * leases :== * * | lease * | leases lease */ void read_lease_db(struct client_lease_tq *lease_db) { struct client_lease *lease, *lp, *nlp; FILE *cfile; int i; TAILQ_INIT(lease_db); if ((cfile = fopen(path_lease_db, "r")) == NULL) return; new_parse(path_lease_db); i = DHO_DHCP_CLIENT_IDENTIFIER; while (feof(cfile) == 0) { if (parse_lease(cfile, &lease) == 0) continue; /* * The new lease will supersede a lease with the same * ssid AND the same Client Identifier AND the same * IP address. */ TAILQ_FOREACH_SAFE(lp, lease_db, next, nlp) { if (lp->ssid_len != lease->ssid_len) continue; if (memcmp(lp->ssid, lease->ssid, lp->ssid_len) != 0) continue; if ((lease->options[i].len != 0) && ((lp->options[i].len != lease->options[i].len) || memcmp(lp->options[i].data, lease->options[i].data, lp->options[i].len) != 0)) continue; if (lp->address.s_addr != lease->address.s_addr) continue; TAILQ_REMOVE(lease_db, lp, next); free_client_lease(lp); } if (lease->epoch == 0) time(&lease->epoch); TAILQ_INSERT_TAIL(lease_db, lease, next); } fclose(cfile); } /* * conf-decl :== * APPEND option SEMI * | BACKOFF_CUTOFF number SEMI * | DEFAULT option SEMI * | FILENAME string SEMI * | FIXED_ADDR ip-address SEMI * | IGNORE option-name-list SEMI * | INITIAL_INTERVAL number SEMI * | INTERFACE interface * | LINK_TIMEOUT number SEMI * | NEXT_SERVER string SEMI * | PREPEND option SEMI * | REBOOT number SEMI * | REJECT ip-address SEMI * | REQUEST option-name-list SEMI * | REQUIRE option-name-list SEMI * | RETRY number SEMI * | SELECT_TIMEOUT number SEMI * | SEND option SEMI * | SERVER_NAME string SEMI * | SUPERSEDE option SEMI * | TIMEOUT number SEMI */ void parse_conf_decl(FILE *cfile, char *name) { uint8_t list[DHO_COUNT]; char *val; enum actions *p; int action, count, i, token; token = next_token(NULL, cfile); switch (token) { case TOK_APPEND: if (parse_option(cfile, &i, config->defaults) == 0) return; action = code_to_action(i, ACTION_APPEND); if (action == ACTION_DEFAULT) parse_warn("'append' treated as 'default'"); config->default_actions[i] = action; break; case TOK_BACKOFF_CUTOFF: if (parse_number(cfile, &config->backoff_cutoff, 0, INT32_MAX) == 0) return; break; case TOK_DEFAULT: if (parse_option(cfile, &i, config->defaults) == 0) return; config->default_actions[i] = ACTION_DEFAULT; break; case TOK_FILENAME: if (parse_string(cfile, &val) == 0) return; free(config->filename); config->filename = val; break; case TOK_FIXED_ADDR: if (parse_ip_addr(cfile, &config->address) == 0) return; break; case TOK_IGNORE: memset(list, 0, sizeof(list)); count = 0; if (parse_option_list(cfile, &count, list) == 0) return; p = config->default_actions; if (count == 0) { for (i = 0; i < DHO_COUNT; i++) if (p[i] == ACTION_IGNORE) p[i] = ACTION_USELEASE; } else { for (i = 0; i < count; i++) p[list[i]] = ACTION_IGNORE; } break; case TOK_INITIAL_INTERVAL: if (parse_number(cfile, &config->initial_interval, 0, INT32_MAX) == 0) return; break; case TOK_INTERFACE: parse_interface(cfile, name); return; case TOK_LINK_TIMEOUT: if (parse_number(cfile, &config->link_interval, 0, INT32_MAX) == 0) return; break; case TOK_NEXT_SERVER: if (parse_ip_addr(cfile, &config->next_server) == 0) return; break; case TOK_PREPEND: if (parse_option(cfile, &i, config->defaults) == 0) return; action = code_to_action(i, ACTION_PREPEND); if (action == ACTION_SUPERSEDE) parse_warn("'prepend' treated as 'supersede'"); config->default_actions[i] = action; break; case TOK_REBOOT: if (parse_number(cfile, &config->reboot_interval, 0, INT32_MAX) == 0) return; break; case TOK_REJECT: if (parse_reject_statement(cfile) == 0) return; break; case TOK_REQUEST: if (parse_option_list(cfile, &config->requested_option_count, config->requested_options) == 0) return; break; case TOK_REQUIRE: if (parse_option_list(cfile, &config->required_option_count, config->required_options) == 0) return; break; case TOK_RETRY: if (parse_number(cfile, &config->retry_interval, 0, INT32_MAX) == 0) return; break; case TOK_SELECT_TIMEOUT: if (parse_number(cfile, &config->select_interval, 0, INT32_MAX) == 0) return; break; case TOK_SEND: if (parse_option(cfile, &i, config->send_options) == 0) return; break; case TOK_SERVER_NAME: if (parse_string(cfile, &val) == 0) return; free(config->server_name); config->server_name = val; break; case TOK_SUPERSEDE: if (parse_option(cfile, &i, config->defaults) == 0) return; config->default_actions[i] = ACTION_SUPERSEDE; break; case TOK_TIMEOUT: if (parse_number(cfile, &config->offer_interval, 0, INT32_MAX) == 0) return; break; case TOK_USELEASE: memset(list, 0, sizeof(list)); count = 0; if (parse_option_list(cfile, &count, list) == 0) return; p = config->default_actions; if (count == 0) { for (i = 0; i < DHO_COUNT; i++) { free(config->defaults[i].data); config->defaults[i].data = NULL; config->defaults[i].len = 0; p[i] = ACTION_USELEASE; } } else { for (i = 0; i < count; i++) { free(config->defaults[list[i]].data); config->defaults[list[i]].data = NULL; config->defaults[list[i]].len = 0; p[list[i]] = ACTION_USELEASE; } } break; default: parse_warn("expecting statement."); skip_to_semi(cfile); return; } parse_semi(cfile); } int parse_hex_octets(FILE *cfile, unsigned int *len, uint8_t **buf) { static uint8_t octets[1500]; char *val, *ep; unsigned long ulval; unsigned int i; int token; i = 0; do { token = next_token(&val, cfile); errno = 0; ulval = strtoul(val, &ep, 16); if ((val[0] == '\0' || *ep != '\0') || (errno == ERANGE && ulval == ULONG_MAX) || (ulval > UINT8_MAX)) break; octets[i++] = ulval; if (peek_token(NULL, cfile) == ';') { *buf = malloc(i); if (*buf == NULL) break; memcpy(*buf, octets, i); *len = i; return 1; } if (i == sizeof(octets)) break; token = next_token(NULL, cfile); } while (token == ':'); parse_warn("expecting colon delimited list of hex octets."); if (token != ';') skip_to_semi(cfile); return 0; } int parse_domain_list(FILE *cfile, int *len, char **dp) { uint8_t buf[DHCP_DOMAIN_SEARCH_LEN]; char *domain; int count, token; memset(buf, 0, sizeof(buf)); count = 0; do { if (parse_string(cfile, &domain) == 0) return 0; count++; if (count > DHCP_DOMAIN_SEARCH_CNT) { parse_warn("more than 6 search domains"); break; } if (count > 1) strlcat(buf, " ", sizeof(buf)); if (strlcat(buf, domain, sizeof(buf)) >= sizeof(buf)) { parse_warn("domain list too long"); break; } token = peek_token(NULL, cfile); if (token == ';') { *dp = strdup(buf); if (*dp == NULL) fatal("domain name list"); *len = strlen(*dp); return 1; } token = next_token(NULL, cfile); if (token != ',') parse_warn("';' or ',' expected"); } while (token == ','); if (token != ';') skip_to_semi(cfile); return 0; } /* * option-list :== * * | option-name * | option-list COMMA option-name */ int parse_option_list(FILE *cfile, int *count, uint8_t *optlist) { uint8_t list[DHO_COUNT]; unsigned int ix, j; int i; int token; char *val; /* Empty list of option names is allowed, to re-init optlist. */ if (peek_token(NULL, cfile) == ';') { memset(optlist, DHO_PAD, sizeof(list)); *count = 0; return 1; } memset(list, 0, sizeof(list)); memcpy(list, optlist, *count); ix = *count; do { /* Next token must be an option name. */ token = next_token(&val, cfile); i = name_to_code(val); if (i == DHO_END) break; /* Avoid storing duplicate options in the list. */ for (j = 0; j < ix && list[j] != i; j++) ; if (j == ix) list[ix++] = i; if (peek_token(NULL, cfile) == ';') { memcpy(optlist, list, sizeof(list)); *count = ix; return 1; } token = next_token(NULL, cfile); } while (token == ','); parse_warn("expecting comma delimited list of option names."); if (token != ';') skip_to_semi(cfile); return 0; } /* * interface :== * string LBRACE conf-decls RBRACE */ int parse_interface(FILE *cfile, char *name) { char *val; int token; token = next_token(&val, cfile); if (token != TOK_STRING) { parse_warn("expecting string."); if (token != ';') skip_to_semi(cfile); return 0; } if (strcmp(name, val) != 0) { skip_to_semi(cfile); return 1; } token = next_token(&val, cfile); if (token != '{') { parse_warn("expecting '{'."); if (token != ';') skip_to_semi(cfile); return 0; } for (;;) { token = peek_token(&val, cfile); if (token == EOF) { parse_warn("unterminated interface declaration."); return 0; } if (token == '}') { token = next_token(NULL, cfile); return 1; } parse_conf_decl(cfile, name); } return 0; } /* * lease :== LEASE RBRACE lease-decls LBRACE * * lease-decls :== * * | lease-decl * | lease-decls lease-decl */ int parse_lease(FILE *cfile, struct client_lease **lp) { struct client_lease *lease; int token; token = next_token(NULL, cfile); if (token == EOF) return 0; if (token != TOK_LEASE) { parse_warn("expecting lease"); if (token != ';') skip_to_semi(cfile); return 0; } token = next_token(NULL, cfile); if (token != '{') { parse_warn("expecting '{'."); if (token != ';') skip_to_semi(cfile); return 0; } lease = calloc(1, sizeof(*lease)); if (lease == NULL) fatal("lease"); for (;;) { token = peek_token(NULL, cfile); if (token == EOF) { parse_warn("unterminated lease."); free_client_lease(lease); break; } if (token == '}') { token = next_token(NULL, cfile); *lp = lease; return 1; } parse_lease_decl(cfile, lease); } return 0; } /* * lease-decl :== * BOOTP SEMI * | EPOCH number SEMI * | EXPIRE SEMI * | FILENAME string SEMI * | FIXED_ADDR ip_address SEMI * | INTERFACE string SEMI * | NEXT_SERVER string SEMI * | OPTION option SEMI * | REBIND SEMI * | RENEW SEMI * | SERVER_NAME string SEMI * | SSID string SEMI */ void parse_lease_decl(FILE *cfile, struct client_lease *lease) { char *val; unsigned int len; int i, token; token = next_token(&val, cfile); switch (token) { case TOK_BOOTP: /* 'bootp' is just a comment. See BOOTP_LEASE(). */ break; case TOK_EPOCH: if (parse_number(cfile, &lease->epoch, INT64_MIN, INT64_MAX) == 0) return; break; case TOK_EXPIRE: /* 'expire' is just a comment. See 'epoch'. */ skip_to_semi(cfile); return; case TOK_FILENAME: if (parse_string(cfile, &val) == 0) return; free(lease->filename); lease->filename = val; break; case TOK_FIXED_ADDR: if (parse_ip_addr(cfile, &lease->address) == 0) return; break; case TOK_INTERFACE: /* 'interface' is just a comment. */ skip_to_semi(cfile); return; case TOK_NEXT_SERVER: if (parse_ip_addr(cfile, &lease->next_server) == 0) return; break; case TOK_OPTION: if (parse_option(cfile, &i, lease->options) == 0) return; break; case TOK_REBIND: case TOK_RENEW: /* 'rebind' & 'renew' are just comments. See 'epoch'. */ skip_to_semi(cfile); return; case TOK_SERVER_NAME: if (parse_string(cfile, &val) == 0) return; free(lease->server_name); lease->server_name = val; break; case TOK_SSID: if (parse_string(cfile, &val) == 0) return; len = strlen(val); if (len > sizeof(lease->ssid)) { free(val); parse_warn("ssid > 32 bytes"); skip_to_semi(cfile); return; } memset(lease->ssid, 0, sizeof(lease->ssid)); memcpy(lease->ssid, val, len); free(val); lease->ssid_len = len; break; default: parse_warn("expecting lease declaration."); skip_to_semi(cfile); return; } parse_semi(cfile); } /* * option :== * option-name option-value * * option-value :== * text * | hex-octets * | signed-32 * | unsigned-32 * | unsigned-16 * | unsigned-8 * | flag * | ip-address * | ip-address-array * | ip-address-pair-array * | uint16-array * | cidr-ip-address-array */ int parse_option(FILE *cfile, int *code, struct option_data *options) { uint8_t hunkbuf[1024], cidr[5], buf[4]; struct in_addr ip_addr; uint8_t *dp; char *fmt, *val; long long number; unsigned int hunkix = 0; int i, freedp, len, token; token = next_token(&val, cfile); i = name_to_code(val); if (i == DHO_END) { parse_warn("expecting option name."); skip_to_semi(cfile); return 0; } /* Parse the option data. */ do { for (fmt = code_to_format(i); *fmt != '\0'; fmt++) { if (*fmt == 'A') break; freedp = 0; switch (*fmt) { case 'X': if (peek_token(NULL, cfile) == TOK_STRING) { if (parse_string(cfile, (char **)&dp) == 0) return 0; len = strlen(dp); } else if (parse_hex_octets(cfile, &len, &dp) == 0) return 0; freedp = 1; break; case 't': /* Text string. */ if (parse_string(cfile, (char **)&dp) == 0) return 0; len = strlen(dp); freedp = 1; break; case 'I': /* IP address. */ if (parse_ip_addr(cfile, &ip_addr) == 0) return 0; len = sizeof(ip_addr); dp = (uint8_t *)&ip_addr; break; case 'l': /* Signed 32-bit integer. */ if (parse_number(cfile, &number, INT32_MIN, INT32_MAX) == 0) return 0; number = htobe64(number); len = sizeof(int32_t); memcpy(buf, (char *)&number + (sizeof(number) - len), len); dp = buf; break; case 'L': /* Unsigned 32-bit integer. */ if (parse_number(cfile, &number, 0, UINT32_MAX) == 0) return 0; number = htobe64(number); len = sizeof(uint32_t); memcpy(buf, (char *)&number + (sizeof(number) - len), len); dp = buf; break; case 'S': /* Unsigned 16-bit integer. */ if (parse_number(cfile, &number, 0, UINT16_MAX) == 0) return 0; number = htobe64(number); len = sizeof(uint16_t); memcpy(buf, (char *)&number + (sizeof(number) - len), len); dp = buf; break; case 'B': /* Unsigned 8-bit integer. */ if (parse_number(cfile, &number, 0, UINT8_MAX) == 0) return 0; buf[0] = number; len = 1; dp = buf; break; case 'f': /* Boolean flag. */ if (parse_boolean(cfile, buf) == 0) return 0; len = 1; dp = buf; break; case 'C': if (parse_cidr(cfile, cidr) == 0) return 0; len = 1 + (cidr[0] + 7) / 8; dp = cidr; break; case 'D': if (peek_token(NULL, cfile) == TOK_STRING) { if (parse_domain_list(cfile, &len, (char **)&dp) == 0) return 0; } else { if (parse_hex_octets(cfile, &len, &dp) == 0) return 0; val = rfc1035_as_string(dp, len); free(dp); dp = strdup(val); if (dp == NULL) fatal("RFC1035 hex octets"); len = strlen(dp); } freedp = 1; break; default: log_warnx("%s: bad format %c in " "parse_option_param", log_procname, *fmt); skip_to_semi(cfile); return 0; } if (dp != NULL && len > 0) { if (hunkix + len > sizeof(hunkbuf)) { if (freedp == 1) free(dp); parse_warn("option data buffer " "overflow"); skip_to_semi(cfile); return 0; } memcpy(&hunkbuf[hunkix], dp, len); hunkix += len; if (freedp == 1) free(dp); } } token = peek_token(NULL, cfile); if (*fmt == 'A' && token == ',') token = next_token(NULL, cfile); } while (*fmt == 'A' && token == ','); free(options[i].data); options[i].data = malloc(hunkix); if (options[i].data == NULL) fatal("option data"); memcpy(options[i].data, hunkbuf, hunkix); options[i].len = hunkix; *code = i; return 1; } int parse_reject_statement(FILE *cfile) { struct in_addr addr; struct reject_elem *elem; if (parse_ip_addr(cfile, &addr) == 0) return 0; TAILQ_FOREACH(elem, &config->reject_list, next) { if (elem->addr.s_addr == addr.s_addr) return 1; } elem = malloc(sizeof(*elem)); if (elem == NULL) fatal("reject address"); elem->addr = addr; TAILQ_INSERT_TAIL(&config->reject_list, elem, next); return 1; } void apply_actions(uint8_t *actions) { int i; for (i = 0; i < DHO_END; i++) { switch (actions[i]) { case ACTION_IGNORE: config->default_actions[i] = ACTION_IGNORE; free(config->defaults[i].data); config->defaults[i].data = NULL; config->defaults[i].len = 0; break; default: break; } } } void set_default_client_identifier(struct ether_addr *hwaddr) { struct option_data *opt; /* * Check both len && data so * * send dhcp-client-identifier ""; * * can be used to suppress sending the default client * identifier. */ opt = &config->send_options[DHO_DHCP_CLIENT_IDENTIFIER]; if (opt->len == 0 && opt->data == NULL) { opt->data = calloc(1, ETHER_ADDR_LEN + 1); if (opt->data == NULL) fatal("default client identifier"); opt->data[0] = HTYPE_ETHER; memcpy(&opt->data[1], hwaddr->ether_addr_octet, ETHER_ADDR_LEN); opt->len = ETHER_ADDR_LEN + 1; } } void set_default_hostname(void) { char hn[HOST_NAME_MAX + 1], *p; struct option_data *opt; int rslt; /* * Check both len && data so * * send host-name ""; * * can be used to suppress sending the default host * name. */ opt = &config->send_options[DHO_HOST_NAME]; if (opt->len == 0 && opt->data == NULL) { rslt = gethostname(hn, sizeof(hn)); if (rslt == -1) { log_warn("host-name"); return; } p = strchr(hn, '.'); if (p != NULL) *p = '\0'; opt->data = strdup(hn); if (opt->data == NULL) fatal("default host-name"); opt->len = strlen(opt->data); } }