/*      $OpenBSD: src/sbin/dhclient/clparse.c,v 1.41 2012/10/27 23:08:53 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 <mellon@fugue.com> 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 "dhcpd.h"
#include "dhctoken.h"

/*
 * client-conf-file :== client-declarations EOF
 * client-declarations :== <nil>
 *                       | client-declaration
 *                       | client-declarations client-declaration
 */
int
read_client_conf(void)
{
        FILE *cfile;
        int token;

        new_parse(path_dhclient_conf);

        /* Set some defaults... */
        config->link_timeout = 30;
        config->timeout = 60;
        config->select_interval = 0;
        config->reboot_timeout = 10;
        config->retry_interval = 300;
        config->backoff_cutoff = 15;
        config->initial_interval = 3;
        config->bootp_policy = ACCEPT;
        config->script_name = _PATH_DHCLIENT_SCRIPT;
        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;
        config->requested_options
            [config->requested_option_count++] = DHO_CLASSLESS_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_NAME_SERVERS;
        config->requested_options
            [config->requested_option_count++] = DHO_HOST_NAME;

        if ((cfile = fopen(path_dhclient_conf, "r")) != NULL) {
                do {
                        token = peek_token(NULL, cfile);
                        if (token == EOF)
                                break;
                        parse_client_statement(cfile);
                } while (1);
                token = next_token(NULL, cfile); /* Clear the peek buffer */
                fclose(cfile);
        }

        return (!warnings_occurred);
}

/*
 * lease-file :== client-lease-statements EOF
 * client-lease-statements :== <nil>
 *                   | client-lease-statements LEASE client-lease-statement
 */
void
read_client_leases(void)
{
        FILE    *cfile;
        int      token;

        new_parse(path_dhclient_db);

        /* Open the lease file.   If we can't open it, just return -
           we can safely trust the server to remember our state. */
        if ((cfile = fopen(path_dhclient_db, "r")) == NULL)
                return;
        do {
                token = next_token(NULL, cfile);
                if (token == EOF)
                        break;
                if (token != TOK_LEASE) {
                        warning("Corrupt lease file - possible data loss!");
                        skip_to_semi(cfile);
                        break;
                } else
                        parse_client_lease_statement(cfile, 0);

        } while (1);
        fclose(cfile);
}

/*
 * client-declaration :==
 *      TOK_SEND option-decl |
 *      TOK_DEFAULT option-decl |
 *      TOK_SUPERSEDE option-decl |
 *      TOK_APPEND option-decl |
 *      TOK_PREPEND option-decl |
 *      TOK_MEDIA string-list |
 *      hardware-declaration |
 *      TOK_REQUEST option-list |
 *      TOK_REQUIRE option-list |
 *      TOK_TIMEOUT number |
 *      TOK_RETRY number |
 *      TOK_SELECT_TIMEOUT number |
 *      TOK_REBOOT number |
 *      TOK_BACKOFF_CUTOFF number |
 *      TOK_INITIAL_INTERVAL number |
 *      TOK_SCRIPT string |
 *      interface-declaration |
 *      TOK_LEASE client-lease-statement |
 *      TOK_ALIAS client-lease-statement |
 *      TOK_REJECT reject-statement
 */
void
parse_client_statement(FILE *cfile)
{
        u_int8_t ignorelist[256];
        int token, code, count, i;

        switch (next_token(NULL, cfile)) {
        case TOK_SEND:
                parse_option_decl(cfile, &config->send_options[0]);
                return;
        case TOK_DEFAULT:
                code = parse_option_decl(cfile, &config->defaults[0]);
                if (code != -1)
                        config->default_actions[code] = ACTION_DEFAULT;
                return;
        case TOK_SUPERSEDE:
                code = parse_option_decl(cfile, &config->defaults[0]);
                if (code != -1)
                        config->default_actions[code] = ACTION_SUPERSEDE;
                return;
        case TOK_IGNORE:
                count = parse_option_list(cfile, ignorelist);
                for (i = 0; i < count; i++)
                        config->default_actions[ignorelist[i]] = ACTION_IGNORE;
                return;
        case TOK_APPEND:
                code = parse_option_decl(cfile, &config->defaults[0]);
                if (code != -1)
                        config->default_actions[code] = ACTION_APPEND;
                return;
        case TOK_PREPEND:
                code = parse_option_decl(cfile, &config->defaults[0]);
                if (code != -1)
                        config->default_actions[code] = ACTION_PREPEND;
                return;
        case TOK_MEDIA:
                skip_to_semi(cfile);
                return;
        case TOK_HARDWARE:
                parse_hardware_param(cfile, &ifi->hw_address);
                return;
        case TOK_REQUEST:
                config->requested_option_count =
                        parse_option_list(cfile, config->requested_options);
                return;
        case TOK_REQUIRE:
                memset(config->required_options, 0,
                    sizeof(config->required_options));
                parse_option_list(cfile, config->required_options);
                return;
        case TOK_LINK_TIMEOUT:
                parse_lease_time(cfile, &config->link_timeout);
                return;
        case TOK_TIMEOUT:
                parse_lease_time(cfile, &config->timeout);
                return;
        case TOK_RETRY:
                parse_lease_time(cfile, &config->retry_interval);
                return;
        case TOK_SELECT_TIMEOUT:
                parse_lease_time(cfile, &config->select_interval);
                return;
        case TOK_REBOOT:
                parse_lease_time(cfile, &config->reboot_timeout);
                return;
        case TOK_BACKOFF_CUTOFF:
                parse_lease_time(cfile, &config->backoff_cutoff);
                return;
        case TOK_INITIAL_INTERVAL:
                parse_lease_time(cfile, &config->initial_interval);
                return;
        case TOK_SCRIPT:
                config->script_name = parse_string(cfile);
                return;
        case TOK_INTERFACE:
                parse_interface_declaration(cfile);
                return;
        case TOK_LEASE:
                parse_client_lease_statement(cfile, 1);
                return;
        case TOK_ALIAS:
                skip_to_semi(cfile);
                return;
        case TOK_REJECT:
                parse_reject_statement(cfile);
                return;
        default:
                parse_warn("expecting a statement.");
                skip_to_semi(cfile);
                break;
        }
        token = next_token(NULL, cfile);
        if (token != ';') {
                parse_warn("semicolon expected.");
                skip_to_semi(cfile);
        }
}

int
parse_X(FILE *cfile, u_int8_t *buf, int max)
{
        int      token;
        char    *val;
        int      len;

        token = peek_token(&val, cfile);
        if (token == TOK_NUMBER_OR_NAME || token == TOK_NUMBER) {
                len = 0;
                do {
                        token = next_token(&val, cfile);
                        if (token != TOK_NUMBER && token != TOK_NUMBER_OR_NAME) {
                                parse_warn("expecting hexadecimal constant.");
                                skip_to_semi(cfile);
                                return (0);
                        }
                        convert_num(&buf[len], val, 16, 8);
                        if (len++ > max) {
                                parse_warn("hexadecimal constant too long.");
                                skip_to_semi(cfile);
                                return (0);
                        }
                        token = peek_token(&val, cfile);
                        if (token == ':')
                                token = next_token(&val, cfile);
                } while (token == ':');
                val = (char *)buf;
        } else if (token == TOK_STRING) {
                token = next_token(&val, cfile);
                len = strlen(val);
                if (len + 1 > max) {
                        parse_warn("string constant too long.");
                        skip_to_semi(cfile);
                        return (0);
                }
                memcpy(buf, val, len + 1);
        } else {
                parse_warn("expecting string or hexadecimal data");
                skip_to_semi(cfile);
                return (0);
        }
        return (len);
}

/*
 * option-list :== option_name |
 *                 option_list COMMA option_name
 */
int
parse_option_list(FILE *cfile, u_int8_t *list)
{
        int      ix, i;
        int      token;
        char    *val;

        ix = 0;
        do {
                token = next_token(&val, cfile);
                if (!is_identifier(token)) {
                        parse_warn("expected option name.");
                        skip_to_semi(cfile);
                        return (0);
                }
                for (i = 0; i < 256; i++)
                        if (!strcasecmp(dhcp_options[i].name, val))
                                break;

                if (i == 256) {
                        parse_warn("%s: unexpected option name.", val);
                        skip_to_semi(cfile);
                        return (0);
                }
                list[ix++] = i;
                if (ix == 256) {
                        parse_warn("%s: too many options.", val);
                        skip_to_semi(cfile);
                        return (0);
                }
                token = next_token(&val, cfile);
        } while (token == ',');
        if (token != ';') {
                parse_warn("expecting semicolon.");
                skip_to_semi(cfile);
                return (0);
        }
        return (ix);
}

/*
 * interface-declaration :==
 *      INTERFACE string LBRACE client-declarations RBRACE
 */
void
parse_interface_declaration(FILE *cfile)
{
        char *val;
        int token;

        token = next_token(&val, cfile);
        if (token != TOK_STRING) {
                parse_warn("expecting interface name (in quotes).");
                skip_to_semi(cfile);
                return;
        }

        if (strcmp(ifi->name, val) != 0) {
                skip_to_semi(cfile);
                return;
        }

        token = next_token(&val, cfile);
        if (token != '{') {
                parse_warn("expecting left brace.");
                skip_to_semi(cfile);
                return;
        }

        do {
                token = peek_token(&val, cfile);
                if (token == EOF) {
                        parse_warn("unterminated interface declaration.");
                        return;
                }
                if (token == '}')
                        break;
                parse_client_statement(cfile);
        } while (1);
        token = next_token(&val, cfile);
}

/*
 * client-lease-statement :==
 *      RBRACE client-lease-declarations LBRACE
 *
 *      client-lease-declarations :==
 *              <nil> |
 *              client-lease-declaration |
 *              client-lease-declarations client-lease-declaration
 */
void
parse_client_lease_statement(FILE *cfile, int is_static)
{
        struct client_lease     *lease, *lp, *pl;
        int                      token;

        token = next_token(NULL, cfile);
        if (token != '{') {
                parse_warn("expecting left brace.");
                skip_to_semi(cfile);
                return;
        }

        lease = malloc(sizeof(struct client_lease));
        if (!lease)
                error("no memory for lease.");
        memset(lease, 0, sizeof(*lease));
        lease->is_static = is_static;

        do {
                token = peek_token(NULL, cfile);
                if (token == EOF) {
                        parse_warn("unterminated lease declaration.");
                        return;
                }
                if (token == '}')
                        break;
                parse_client_lease_declaration(cfile, lease);
        } while (1);
        token = next_token(NULL, cfile);

        /* If the lease declaration didn't include an interface
         * declaration that we recognized, it's of no use to us.
         */
        if (!ifi) {
                free_client_lease(lease);
                return;
        }

        /*
         * The new lease may supersede a lease that's not the active
         * lease but is still on the lease list, so scan the lease list
         * looking for a lease with the same address, and if we find it,
         * toss it.
         */
        pl = NULL;
        for (lp = client->leases; lp; lp = lp->next) {
                if (addr_eq(lp->address, lease->address)) {
                        if (pl)
                                pl->next = lp->next;
                        else
                                client->leases = lp->next;
                        free_client_lease(lp);
                        break;
                } else
                        pl = lp;
        }

        /*
         * If this is a preloaded lease, just put it on the list of
         * recorded leases - don't make it the active lease.
         */
        if (is_static) {
                lease->next = client->leases;
                client->leases = lease;
                return;
        }

        /*
         * The last lease in the lease file on a particular interface is
         * the active lease for that interface.    Of course, we don't
         * know what the last lease in the file is until we've parsed
         * the whole file, so at this point, we assume that the lease we
         * just parsed is the active lease for its interface.   If
         * there's already an active lease for the interface, and this
         * lease is for the same ip address, then we just toss the old
         * active lease and replace it with this one.   If this lease is
         * for a different address, then if the old active lease has
         * expired, we dump it; if not, we put it on the list of leases
         * for this interface which are still valid but no longer
         * active.
         */
        if (client->active) {
                if (client->active->expiry < time(NULL))
                        free_client_lease(client->active);
                else if (addr_eq(client->active->address, lease->address))
                        free_client_lease(client->active);
                else {
                        client->active->next = client->leases;
                        client->leases = client->active;
                }
        }
        client->active = lease;

        /* Phew. */
}

/*
 * client-lease-declaration :==
 *      BOOTP |
 *      INTERFACE string |
 *      FIXED_ADDR ip_address |
 *      FILENAME string |
 *      SERVER_NAME string |
 *      OPTION option-decl |
 *      RENEW time-decl |
 *      REBIND time-decl |
 *      EXPIRE time-decl
 */
void
parse_client_lease_declaration(FILE *cfile, struct client_lease *lease)
{
        char *val;
        int token;

        switch (next_token(&val, cfile)) {
        case TOK_BOOTP:
                lease->is_bootp = 1;
                break;
        case TOK_INTERFACE:
                token = next_token(&val, cfile);
                if (token != TOK_STRING) {
                        parse_warn("expecting interface name (in quotes).");
                        skip_to_semi(cfile);
                        break;
                }
                if (strcmp(ifi->name, val) != 0) {
                        parse_warn("wrong interface name. Expecting '%s'.",
                           ifi->name);
                        skip_to_semi(cfile);
                        break;
                }
                break;
        case TOK_FIXED_ADDR:
                if (!parse_ip_addr(cfile, &lease->address))
                        return;
                break;
        case TOK_MEDIUM:
                skip_to_semi(cfile);
                return;
        case TOK_FILENAME:
                lease->filename = parse_string(cfile);
                return;
        case TOK_SERVER_NAME:
                lease->server_name = parse_string(cfile);
                return;
        case TOK_RENEW:
                lease->renewal = parse_date(cfile);
                return;
        case TOK_REBIND:
                lease->rebind = parse_date(cfile);
                return;
        case TOK_EXPIRE:
                lease->expiry = parse_date(cfile);
                return;
        case TOK_OPTION:
                parse_option_decl(cfile, lease->options);
                return;
        default:
                parse_warn("expecting lease declaration.");
                skip_to_semi(cfile);
                break;
        }
        token = next_token(&val, cfile);
        if (token != ';') {
                parse_warn("expecting semicolon.");
                skip_to_semi(cfile);
        }
}

int
parse_option_decl(FILE *cfile, struct option_data *options)
{
        char            *val;
        int              token;
        u_int8_t         buf[4];
        u_int8_t         hunkbuf[1024];
        int              hunkix = 0;
        char            *fmt;
        struct iaddr     ip_addr;
        u_int8_t        *dp;
        int              len, code;
        int              nul_term = 0;

        token = next_token(&val, cfile);
        if (!is_identifier(token)) {
                parse_warn("expecting identifier after option keyword.");
                if (token != ';')
                        skip_to_semi(cfile);
                return (-1);
        }

        /* Look up the actual option info. */
        fmt = NULL;
        for (code = 0; code < 256; code++)
                if (strcmp(dhcp_options[code].name, val) == 0)
                        break;

        if (code > 255) {
                parse_warn("no option named %s", val);
                skip_to_semi(cfile);
                return (-1);
        }

        /* Parse the option data... */
        do {
                for (fmt = dhcp_options[code].format; *fmt; fmt++) {
                        if (*fmt == 'A')
                                break;
                        switch (*fmt) {
                        case 'X':
                                len = parse_X(cfile, &hunkbuf[hunkix],
                                    sizeof(hunkbuf) - hunkix);
                                hunkix += len;
                                break;
                        case 't': /* Text string... */
                                token = next_token(&val, cfile);
                                if (token != TOK_STRING) {
                                        parse_warn("expecting string.");
                                        skip_to_semi(cfile);
                                        return (-1);
                                }
                                len = strlen(val);
                                if (hunkix + len + 1 > sizeof(hunkbuf)) {
                                        parse_warn("option data buffer %s",
                                            "overflow");
                                        skip_to_semi(cfile);
                                        return (-1);
                                }
                                memcpy(&hunkbuf[hunkix], val, len + 1);
                                nul_term = 1;
                                hunkix += len;
                                break;
                        case 'I': /* IP address. */
                                if (!parse_ip_addr(cfile, &ip_addr))
                                        return (-1);
                                len = ip_addr.len;
                                dp = ip_addr.iabuf;
alloc:
                                if (hunkix + len > sizeof(hunkbuf)) {
                                        parse_warn("option data buffer "
                                            "overflow");
                                        skip_to_semi(cfile);
                                        return (-1);
                                }
                                memcpy(&hunkbuf[hunkix], dp, len);
                                hunkix += len;
                                break;
                        case 'L':       /* Unsigned 32-bit integer... */
                        case 'l':       /* Signed 32-bit integer... */
                                token = next_token(&val, cfile);
                                if (token != TOK_NUMBER) {
need_number:
                                        parse_warn("expecting number.");
                                        if (token != ';')
                                                skip_to_semi(cfile);
                                        return (-1);
                                }
                                convert_num(buf, val, 0, 32);
                                len = 4;
                                dp = buf;
                                goto alloc;
                        case 's':       /* Signed 16-bit integer. */
                        case 'S':       /* Unsigned 16-bit integer. */
                                token = next_token(&val, cfile);
                                if (token != TOK_NUMBER)
                                        goto need_number;
                                convert_num(buf, val, 0, 16);
                                len = 2;
                                dp = buf;
                                goto alloc;
                        case 'b':       /* Signed 8-bit integer. */
                        case 'B':       /* Unsigned 8-bit integer. */
                                token = next_token(&val, cfile);
                                if (token != TOK_NUMBER)
                                        goto need_number;
                                convert_num(buf, val, 0, 8);
                                len = 1;
                                dp = buf;
                                goto alloc;
                        case 'f': /* Boolean flag. */
                                token = next_token(&val, cfile);
                                if (!is_identifier(token)) {
                                        parse_warn("expecting identifier.");
bad_flag:
                                        if (token != ';')
                                                skip_to_semi(cfile);
                                        return (-1);
                                }
                                if (!strcasecmp(val, "true") ||
                                    !strcasecmp(val, "on"))
                                        buf[0] = 1;
                                else if (!strcasecmp(val, "false") ||
                                    !strcasecmp(val, "off"))
                                        buf[0] = 0;
                                else {
                                        parse_warn("expecting boolean.");
                                        goto bad_flag;
                                }
                                len = 1;
                                dp = buf;
                                goto alloc;
                        default:
                                warning("Bad format %c in parse_option_param.",
                                    *fmt);
                                skip_to_semi(cfile);
                                return (-1);
                        }
                }
                token = next_token(&val, cfile);
        } while (*fmt == 'A' && token == ',');

        if (token != ';') {
                parse_warn("semicolon expected.");
                skip_to_semi(cfile);
                return (-1);
        }

        options[code].data = malloc(hunkix + nul_term);
        if (!options[code].data)
                error("out of memory allocating option data.");
        memcpy(options[code].data, hunkbuf, hunkix + nul_term);
        options[code].len = hunkix;
        return (code);
}

void
parse_reject_statement(FILE *cfile)
{
        struct iaddrlist *list;
        struct iaddr addr;
        int token;

        do {
                if (!parse_ip_addr(cfile, &addr)) {
                        parse_warn("expecting IP address.");
                        skip_to_semi(cfile);
                        return;
                }

                list = malloc(sizeof(struct iaddrlist));
                if (!list)
                        error("no memory for reject list!");

                list->addr = addr;
                list->next = config->reject_list;
                config->reject_list = list;

                token = next_token(NULL, cfile);
        } while (token == ',');

        if (token != ';') {
                parse_warn("expecting semicolon.");
                skip_to_semi(cfile);
        }
}