/*      $OpenBSD: parser.c,v 1.6 2024/09/15 05:26:05 yasuoka Exp $      */

/*
 * Copyright (c) 2010 Reyk Floeter <reyk@vantronix.net>
 * Copyright (c) 2004 Esben Norby <norby@openbsd.org>
 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/time.h>

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <limits.h>

#include "parser.h"

enum token_type {
        NOTOKEN,
        KEYWORD,
        HOSTNAME,
        SECRET,
        USERNAME,
        PASSWORD,
        PORT,
        METHOD,
        NAS_PORT,
        TRIES,
        INTERVAL,
        MAXWAIT,
        FLAGS,
        SESSION_SEQ,
        MSGAUTH,
        ENDTOKEN
};

struct token {
        enum token_type          type;
        const char              *keyword;
        int                      value;
        const struct token      *next;
};

static struct parse_result res = {
        .tries          = TEST_TRIES_DEFAULT,
        .interval       = { TEST_INTERVAL_DEFAULT, 0 },
        .maxwait        = { TEST_MAXWAIT_DEFAULT, 0 },
        .msgauth        = 1
};

static const struct token t_test[];
static const struct token t_secret[];
static const struct token t_username[];
static const struct token t_test_opts[];
static const struct token t_password[];
static const struct token t_port[];
static const struct token t_method[];
static const struct token t_nas_port[];
static const struct token t_tries[];
static const struct token t_interval[];
static const struct token t_maxwait[];
static const struct token t_yesno[];
static const struct token t_ipcp[];
static const struct token t_ipcp_flags[];
static const struct token t_ipcp_session_seq[];

static const struct token t_main[] = {
        { KEYWORD,      "test",         TEST,           t_test },
        { KEYWORD,      "ipcp",         NONE,           t_ipcp },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_test[] = {
        { HOSTNAME,     "",             NONE,           t_secret },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_secret[] = {
        { SECRET,       "",             NONE,           t_username },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_username[] = {
        { USERNAME,     "",             NONE,           t_test_opts },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_test_opts[] = {
        { NOTOKEN,      "",             NONE,           NULL },
        { KEYWORD,      "password",     NONE,           t_password },
        { KEYWORD,      "port",         NONE,           t_port },
        { KEYWORD,      "method",       NONE,           t_method },
        { KEYWORD,      "nas-port",     NONE,           t_nas_port },
        { KEYWORD,      "interval",     NONE,           t_interval },
        { KEYWORD,      "tries",        NONE,           t_tries },
        { KEYWORD,      "maxwait",      NONE,           t_maxwait },
        { KEYWORD,      "msgauth",      NONE,           t_yesno },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_password[] = {
        { PASSWORD,     "",             NONE,           t_test_opts },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_port[] = {
        { PORT,         "",             NONE,           t_test_opts },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_method[] = {
        { METHOD,       "",             NONE,           t_test_opts },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_nas_port[] = {
        { NAS_PORT,     "",             NONE,           t_test_opts },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_tries[] = {
        { TRIES,        "",             NONE,           t_test_opts },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_interval[] = {
        { INTERVAL,     "",             NONE,           t_test_opts },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_maxwait[] = {
        { MAXWAIT,      "",             NONE,           t_test_opts },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_yesno[] = {
        { MSGAUTH,      "yes",          1,              t_test_opts },
        { MSGAUTH,      "no",           0,              t_test_opts },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_ipcp[] = {
        { KEYWORD,      "show",         IPCP_SHOW,      NULL },
        { KEYWORD,      "dump",         IPCP_DUMP,      t_ipcp_flags },
        { KEYWORD,      "monitor",      IPCP_MONITOR,   t_ipcp_flags },
        { KEYWORD,      "disconnect",   IPCP_DISCONNECT,t_ipcp_session_seq },
        { KEYWORD,      "delete",       IPCP_DELETE,    t_ipcp_session_seq },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_ipcp_flags[] = {
        { NOTOKEN,      "",             NONE,           NULL },
        { FLAGS,        "-json",        FLAGS_JSON,     NULL },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token t_ipcp_session_seq[] = {
        { SESSION_SEQ,  "",             NONE,           NULL },
        { ENDTOKEN,     "",             NONE,           NULL }
};

static const struct token       *match_token(char *, const struct token []);
static void                      show_valid_args(const struct token []);

struct parse_result *
parse(int argc, char *argv[])
{
        const struct token      *table = t_main;
        const struct token      *match;

        while (argc >= 0) {
                if ((match = match_token(argv[0], table)) == NULL) {
                        fprintf(stderr, "valid commands/args:\n");
                        show_valid_args(table);
                        return (NULL);
                }

                argc--;
                argv++;

                if (match->type == NOTOKEN || match->next == NULL)
                        break;

                table = match->next;
        }

        if (argc > 0) {
                fprintf(stderr, "superfluous argument: %s\n", argv[0]);
                return (NULL);
        }

        if (res.tries * res.interval.tv_sec > res.maxwait.tv_sec) {
                fprintf(stderr, "tries %u by interval %lld > maxwait %lld",
                    res.tries, res.interval.tv_sec, res.maxwait.tv_sec);
                return (NULL);
        }

        return (&res);
}

static const struct token *
match_token(char *word, const struct token table[])
{
        u_int                    i, match = 0;
        const struct token      *t = NULL;
        long long                num;
        const char              *errstr;
        size_t                   wordlen = 0;

        if (word != NULL)
                wordlen = strlen(word);

        for (i = 0; table[i].type != ENDTOKEN; i++) {
                switch (table[i].type) {
                case NOTOKEN:
                        if (word == NULL || strlen(word) == 0) {
                                match++;
                                t = &table[i];
                        }
                        break;
                case KEYWORD:
                        if (word != NULL && strncmp(word, table[i].keyword,
                            wordlen) == 0) {
                                match++;
                                t = &table[i];
                                if (t->value)
                                        res.action = t->value;
                        }
                        break;
                case HOSTNAME:
                        if (word == NULL)
                                break;
                        match++;
                        res.hostname = word;
                        t = &table[i];
                        break;
                case SECRET:
                        if (word == NULL)
                                break;
                        match++;
                        res.secret = word;
                        t = &table[i];
                        break;
                case USERNAME:
                        if (word == NULL)
                                break;
                        match++;
                        res.username = word;
                        t = &table[i];
                        break;
                case PASSWORD:
                        if (word == NULL)
                                break;
                        match++;
                        res.password = word;
                        t = &table[i];
                        break;
                case PORT:
                        if (word == NULL)
                                break;
                        num = strtonum(word, 1, UINT16_MAX, &errstr);
                        if (errstr != NULL) {
                                fprintf(stderr,
                                    "invalid argument: %s is %s for \"port\"\n",
                                    word, errstr);
                                return (NULL);
                        }
                        match++;
                        res.port = num;
                        t = &table[i];
                        break;
                case METHOD:
                        if (word == NULL)
                                break;
                        if (strcasecmp(word, "pap") == 0)
                                res.auth_method = PAP;
                        else if (strcasecmp(word, "chap") == 0)
                                res.auth_method = CHAP;
                        else if (strcasecmp(word, "mschapv2") == 0)
                                res.auth_method = MSCHAPV2;
                        else {
                                fprintf(stderr,
                                    "invalid argument: %s for \"method\"\n",
                                    word);
                                return (NULL);
                        }
                        match++;
                        t = &table[i];
                        break;
                case NAS_PORT:
                        if (word == NULL)
                                break;
                        num = strtonum(word, 0, 65535, &errstr);
                        if (errstr != NULL) {
                                fprintf(stderr,
                                    "invalid argument: %s is %s for "
                                    "\"nas-port\"\n", word, errstr);
                                return (NULL);
                        }
                        match++;
                        res.nas_port = num;
                        t = &table[i];
                        break;

                case TRIES:
                        if (word == NULL)
                                break;
                        num = strtonum(word,
                            TEST_TRIES_MIN, TEST_TRIES_MAX, &errstr);
                        if (errstr != NULL) {
                                printf("invalid argument: %s is %s"
                                    " for \"tries\"\n", word, errstr);
                                return (NULL);
                        }
                        match++;
                        res.tries = num;
                        t = &table[i];
                        break;
                case INTERVAL:
                        if (word == NULL)
                                break;
                        num = strtonum(word,
                            TEST_INTERVAL_MIN, TEST_INTERVAL_MAX, &errstr);
                        if (errstr != NULL) {
                                printf("invalid argument: %s is %s"
                                    " for \"interval\"\n", word, errstr);
                                return (NULL);
                        }
                        match++;
                        res.interval.tv_sec = num;
                        t = &table[i];
                        break;
                case MAXWAIT:
                        if (word == NULL)
                                break;
                        num = strtonum(word,
                            TEST_MAXWAIT_MIN, TEST_MAXWAIT_MAX, &errstr);
                        if (errstr != NULL) {
                                printf("invalid argument: %s is %s"
                                    " for \"maxwait\"\n", word, errstr);
                                return (NULL);
                        }
                        match++;
                        res.maxwait.tv_sec = num;
                        t = &table[i];
                        break;
                case FLAGS:
                        if (word != NULL && wordlen >= 2 &&
                            strncmp(word, table[i].keyword, wordlen) == 0) {
                                match++;
                                t = &table[i];
                                if (t->value)
                                        res.flags |= t->value;
                        }
                        break;
                case SESSION_SEQ:
                        if (word == NULL)
                                break;
                        match++;
                        res.session_seq = strtonum(word, 1, UINT_MAX, &errstr);
                        if (errstr != NULL) {
                                printf("invalid argument: %s is %s for "
                                    "\"session-id\"\n", word, errstr);
                                return (NULL);
                        }
                        t = &table[i];
                case MSGAUTH:
                        if (word != NULL &&
                            strcmp(word, table[i].keyword) == 0) {
                                match++;
                                res.msgauth = table[i].value;
                                t = &table[i];
                        }
                        break;
                case ENDTOKEN:
                        break;
                }
        }

        if (match != 1) {
                if (word == NULL)
                        fprintf(stderr, "missing argument:\n");
                else if (match > 1)
                        fprintf(stderr, "ambiguous argument: %s\n", word);
                else if (match < 1)
                        fprintf(stderr, "unknown argument: %s\n", word);
                return (NULL);
        }

        return (t);
}

static void
show_valid_args(const struct token table[])
{
        int     i;

        for (i = 0; table[i].type != ENDTOKEN; i++) {
                switch (table[i].type) {
                case NOTOKEN:
                        fprintf(stderr, "  <cr>\n");
                        break;
                case KEYWORD:
                        fprintf(stderr, "  %s\n", table[i].keyword);
                        break;
                case HOSTNAME:
                        fprintf(stderr, "  <hostname>\n");
                        break;
                case SECRET:
                        fprintf(stderr, "  <radius secret>\n");
                        break;
                case USERNAME:
                        fprintf(stderr, "  <username>\n");
                        break;
                case PASSWORD:
                        fprintf(stderr, "  <password>\n");
                        break;
                case PORT:
                        fprintf(stderr, "  <port number>\n");
                        break;
                case METHOD:
                        fprintf(stderr, "  <auth method (pap, chap, "
                            "mschapv2)>\n");
                        break;
                case NAS_PORT:
                        fprintf(stderr, "  <nas-port (0-65535)>\n");
                        break;
                case TRIES:
                        fprintf(stderr, "  <tries (%u-%u)>\n",
                            TEST_TRIES_MIN, TEST_TRIES_MAX);
                        break;
                case INTERVAL:
                        fprintf(stderr, "  <interval (%u-%u)>\n",
                            TEST_INTERVAL_MIN, TEST_INTERVAL_MAX);
                        break;
                case MAXWAIT:
                        fprintf(stderr, "  <maxwait (%u-%u)>\n",
                            TEST_MAXWAIT_MIN, TEST_MAXWAIT_MAX);
                        break;
                case FLAGS:
                        fprintf(stderr, "  %s\n", table[i].keyword);
                        break;
                case SESSION_SEQ:
                        fprintf(stderr, "  <sequence number>\n");
                        break;
                case MSGAUTH:
                        fprintf(stderr, "  %s\n", table[i].keyword);
                        break;
                case ENDTOKEN:
                        break;
                }
        }
}