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/* parse.c

   Common parser code for dhcpd and dhclient. */

/*
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 * Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.
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 * 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''.
 */

#ifndef lint
static char copyright[] =
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"$Id: parse.c,v 1.7 1998/06/25 03:07:51 mellon Exp $ Copyright (c) 1995, 1996 The Internet Software Consortium.  All rights reserved.\n";
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#endif /* not lint */

#include "dhcpd.h"
#include "dhctoken.h"

/* Skip to the semicolon ending the current statement.   If we encounter
   braces, the matching closing brace terminates the statement.   If we
   encounter a right brace but haven't encountered a left brace, return
   leaving the brace in the token buffer for the caller.   If we see a
   semicolon and haven't seen a left brace, return.   This lets us skip
   over:

   	statement;
	statement foo bar { }
	statement foo bar { statement { } }
	statement}
 
	...et cetera. */

void skip_to_semi (cfile)
	FILE *cfile;
{
	int token;
	char *val;
	int brace_count = 0;

	do {
		token = peek_token (&val, cfile);
		if (token == RBRACE) {
			if (brace_count) {
				token = next_token (&val, cfile);
				if (!--brace_count)
					return;
			} else
				return;
		} else if (token == LBRACE) {
			brace_count++;
		} else if (token == SEMI && !brace_count) {
			token = next_token (&val, cfile);
			return;
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		} else if (token == EOL) {
			/* EOL only happens when parsing /etc/resolv.conf,
			   and we treat it like a semicolon because the
			   resolv.conf file is line-oriented. */
			token = next_token (&val, cfile);
			return;
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		}
		token = next_token (&val, cfile);
	} while (token != EOF);
}

int parse_semi (cfile)
	FILE *cfile;
{
	int token;
	char *val;

	token = next_token (&val, cfile);
	if (token != SEMI) {
		parse_warn ("semicolon expected.");
		skip_to_semi (cfile);
		return 0;
	}
	return 1;
}

/* string-parameter :== STRING SEMI */

char *parse_string (cfile)
	FILE *cfile;
{
	char *val;
	int token;
	char *s;

	token = next_token (&val, cfile);
	if (token != STRING) {
		parse_warn ("filename must be a string");
		skip_to_semi (cfile);
		return (char *)0;
	}
	s = (char *)malloc (strlen (val) + 1);
	if (!s)
		error ("no memory for string %s.", val);
	strcpy (s, val);

	if (!parse_semi (cfile))
		return (char *)0;
	return s;
}

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/*
 * hostname :== IDENTIFIER
 *		| IDENTIFIER DOT
 *		| hostname DOT IDENTIFIER
 */
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char *parse_host_name (cfile)
	FILE *cfile;
{
	char *val;
	int token;
	int len = 0;
	char *s;
	char *t;
	pair c = (pair)0;
	
	/* Read a dotted hostname... */
	do {
		/* Read a token, which should be an identifier. */
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		token = peek_token (&val, cfile);
		if (!is_identifier (token) && token != NUMBER)
			break;
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		token = next_token (&val, cfile);
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		/* Store this identifier... */
		if (!(s = (char *)malloc (strlen (val) + 1)))
			error ("can't allocate temp space for hostname.");
		strcpy (s, val);
		c = cons ((caddr_t)s, c);
		len += strlen (s) + 1;
		/* Look for a dot; if it's there, keep going, otherwise
		   we're done. */
		token = peek_token (&val, cfile);
		if (token == DOT)
			token = next_token (&val, cfile);
	} while (token == DOT);

	/* Assemble the hostname together into a string. */
	if (!(s = (char *)malloc (len)))
		error ("can't allocate space for hostname.");
	t = s + len;
	*--t = 0;
	while (c) {
		pair cdr = c -> cdr;
		int l = strlen ((char *)(c -> car));
		t -= l;
		memcpy (t, (char *)(c -> car), l);
		/* Free up temp space. */
		free (c -> car);
		free (c);
		c = cdr;
		if (t != s)
			*--t = '.';
	}
	return s;
}

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/* ip-addr-or-hostname :== ip-address | hostname
   ip-address :== NUMBER DOT NUMBER DOT NUMBER DOT NUMBER
   
   Parse an ip address or a hostname.   If uniform is zero, put in
   an expr_substring node to limit hostnames that evaluate to more
   than one IP address. */

struct expression *parse_ip_addr_or_hostname (cfile, uniform)
	FILE *cfile;
	int uniform;
{
	char *val;
	int token;
	unsigned char addr [4];
	int len = sizeof addr;
	char *name;
	struct expression *rv;

	token = peek_token (&val, cfile);
	if (is_identifier (token)) {
		name = parse_host_name (cfile);
		if (!name)
			return (struct expression *)0;
		rv = make_host_lookup (name);
		if (!uniform)
			rv = make_limit (rv, 4);
	} else if (token == NUMBER) {
		if (!parse_numeric_aggregate (cfile, addr, &len, DOT, 10, 8))
			return (struct expression *)0;
		rv = make_const_data (addr, len, 0, 0);
	} else {
		if (token != RBRACE && token != LBRACE)
			token = next_token (&val, cfile);
		parse_warn ("%s (%d): expecting IP address or hostname",
			    val, token);
		if (token != SEMI)
			skip_to_semi (cfile);
		return (struct expression *)0;
	}

	return rv;
}	
	
/*
 * ip-address :== NUMBER DOT NUMBER DOT NUMBER DOT NUMBER
 */

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int parse_ip_addr (cfile, addr)
	FILE *cfile;
	struct iaddr *addr;
{
	char *val;
	int token;

	addr -> len = 4;
	if (parse_numeric_aggregate (cfile, addr -> iabuf,
				     &addr -> len, DOT, 10, 8))
		return 1;
	return 0;
}	

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/*
 * hardware-parameter :== HARDWARE hardware-type colon-seperated-hex-list SEMI
 * hardware-type :== ETHERNET | TOKEN_RING
 */
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void parse_hardware_param (cfile, hardware)
	FILE *cfile;
	struct hardware *hardware;
{
	char *val;
	int token;
	int hlen;
	unsigned char *t;

	token = next_token (&val, cfile);
	switch (token) {
	      case ETHERNET:
		hardware -> htype = HTYPE_ETHER;
		break;
	      case TOKEN_RING:
		hardware -> htype = HTYPE_IEEE802;
		break;
	      default:
		parse_warn ("expecting a network hardware type");
		skip_to_semi (cfile);
		return;
	}

	/* Parse the hardware address information.   Technically,
	   it would make a lot of sense to restrict the length of the
	   data we'll accept here to the length of a particular hardware
	   address type.   Unfortunately, there are some broken clients
	   out there that put bogus data in the chaddr buffer, and we accept
	   that data in the lease file rather than simply failing on such
	   clients.   Yuck. */
	hlen = 0;
	t = parse_numeric_aggregate (cfile, (unsigned char *)0, &hlen,
				     COLON, 16, 8);
	if (!t)
		return;
	if (hlen > sizeof hardware -> haddr) {
		free (t);
		parse_warn ("hardware address too long");
	} else {
		hardware -> hlen = hlen;
		memcpy ((unsigned char *)&hardware -> haddr [0],
			t, hardware -> hlen);
		free (t);
	}
	
	token = next_token (&val, cfile);
	if (token != SEMI) {
		parse_warn ("expecting semicolon.");
		skip_to_semi (cfile);
	}
}

/* lease-time :== NUMBER SEMI */

void parse_lease_time (cfile, timep)
	FILE *cfile;
	TIME *timep;
{
	char *val;
	int token;

	token = next_token (&val, cfile);
	if (token != NUMBER) {
		parse_warn ("Expecting numeric lease time");
		skip_to_semi (cfile);
		return;
	}
	convert_num ((unsigned char *)timep, val, 10, 32);
	/* Unswap the number - convert_num returns stuff in NBO. */
	*timep = ntohl (*timep); /* XXX */

	parse_semi (cfile);
}

/* No BNF for numeric aggregates - that's defined by the caller.  What
   this function does is to parse a sequence of numbers seperated by
   the token specified in seperator.  If max is zero, any number of
   numbers will be parsed; otherwise, exactly max numbers are
   expected.  Base and size tell us how to internalize the numbers
   once they've been tokenized. */

unsigned char *parse_numeric_aggregate (cfile, buf,
					max, seperator, base, size)
	FILE *cfile;
	unsigned char *buf;
	int *max;
	int seperator;
	int base;
	int size;
{
	char *val;
	int token;
	unsigned char *bufp = buf, *s, *t;
	int count = 0;
	pair c = (pair)0;

	if (!bufp && *max) {
		bufp = (unsigned char *)malloc (*max * size / 8);
		if (!bufp)
			error ("can't allocate space for numeric aggregate");
	} else
		s = bufp;

	do {
		if (count) {
			token = peek_token (&val, cfile);
			if (token != seperator) {
				if (!*max)
					break;
				if (token != RBRACE && token != LBRACE)
					token = next_token (&val, cfile);
				parse_warn ("too few numbers.");
				if (token != SEMI)
					skip_to_semi (cfile);
				return (unsigned char *)0;
			}
			token = next_token (&val, cfile);
		}
		token = next_token (&val, cfile);

		if (token == EOF) {
			parse_warn ("unexpected end of file");
			break;
		}

		/* Allow NUMBER_OR_NAME if base is 16. */
		if (token != NUMBER &&
		    (base != 16 || token != NUMBER_OR_NAME)) {
			parse_warn ("expecting numeric value.");
			skip_to_semi (cfile);
			return (unsigned char *)0;
		}
		/* If we can, convert the number now; otherwise, build
		   a linked list of all the numbers. */
		if (s) {
			convert_num (s, val, base, size);
			s += size / 8;
		} else {
			t = (unsigned char *)malloc (strlen (val) + 1);
			if (!t)
				error ("no temp space for number.");
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			strcpy ((char *)t, val);
			c = cons ((caddr_t)t, c);
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		}
	} while (++count != *max);

	/* If we had to cons up a list, convert it now. */
	if (c) {
		bufp = (unsigned char *)malloc (count * size / 8);
		if (!bufp)
			error ("can't allocate space for numeric aggregate.");
		s = bufp + count - size / 8;
		*max = count;
	}
	while (c) {
		pair cdr = c -> cdr;
		convert_num (s, (char *)(c -> car), base, size);
		s -= size / 8;
		/* Free up temp space. */
		free (c -> car);
		free (c);
		c = cdr;
	}
	return bufp;
}

void convert_num (buf, str, base, size)
	unsigned char *buf;
	char *str;
	int base;
	int size;
{
	char *ptr = str;
	int negative = 0;
	u_int32_t val = 0;
	int tval;
	int max;

	if (*ptr == '-') {
		negative = 1;
		++ptr;
	}

	/* If base wasn't specified, figure it out from the data. */
	if (!base) {
		if (ptr [0] == '0') {
			if (ptr [1] == 'x') {
				base = 16;
				ptr += 2;
			} else if (isascii (ptr [1]) && isdigit (ptr [1])) {
				base = 8;
				ptr += 1;
			} else {
				base = 10;
			}
		} else {
			base = 10;
		}
	}

	do {
		tval = *ptr++;
		/* XXX assumes ASCII... */
		if (tval >= 'a')
			tval = tval - 'a' + 10;
		else if (tval >= 'A')
			tval = tval - 'A' + 10;
		else if (tval >= '0')
			tval -= '0';
		else {
			warn ("Bogus number: %s.", str);
			break;
		}
		if (tval >= base) {
			warn ("Bogus number: %s: digit %d not in base %d\n",
			      str, tval, base);
			break;
		}
		val = val * base + tval;
	} while (*ptr);

	if (negative)
		max = (1 << (size - 1));
	else
		max = (1 << (size - 1)) + ((1 << (size - 1)) - 1);
	if (val > max) {
		switch (base) {
		      case 8:
			warn ("value %s%o exceeds max (%d) for precision.",
			      negative ? "-" : "", val, max);
			break;
		      case 16:
			warn ("value %s%x exceeds max (%d) for precision.",
			      negative ? "-" : "", val, max);
			break;
		      default:
			warn ("value %s%u exceeds max (%d) for precision.",
			      negative ? "-" : "", val, max);
			break;
		}
	}

	if (negative) {
		switch (size) {
		      case 8:
			*buf = -(unsigned long)val;
			break;
		      case 16:
			putShort (buf, -(unsigned long)val);
			break;
		      case 32:
			putLong (buf, -(unsigned long)val);
			break;
		      default:
			warn ("Unexpected integer size: %d\n", size);
			break;
		}
	} else {
		switch (size) {
		      case 8:
			*buf = (u_int8_t)val;
			break;
		      case 16:
			putUShort (buf, (u_int16_t)val);
			break;
		      case 32:
			putULong (buf, val);
			break;
		      default:
			warn ("Unexpected integer size: %d\n", size);
			break;
		}
	}
}

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/*
 * date :== NUMBER NUMBER SLASH NUMBER SLASH NUMBER 
 *		NUMBER COLON NUMBER COLON NUMBER SEMI
 *
 * Dates are always in GMT; first number is day of week; next is
 * year/month/day; next is hours:minutes:seconds on a 24-hour
 * clock.
 */
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TIME parse_date (cfile)
	FILE *cfile;
{
	struct tm tm;
	int guess;
	char *val;
	int token;
	static int months [11] = { 31, 59, 90, 120, 151, 181,
					  212, 243, 273, 304, 334 };

	/* Day of week... */
	token = next_token (&val, cfile);
	if (token != NUMBER) {
		parse_warn ("numeric day of week expected.");
		if (token != SEMI)
			skip_to_semi (cfile);
		return (TIME)0;
	}
	tm.tm_wday = atoi (val);

	/* Year... */
	token = next_token (&val, cfile);
	if (token != NUMBER) {
		parse_warn ("numeric year expected.");
		if (token != SEMI)
			skip_to_semi (cfile);
		return (TIME)0;
	}
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	/* Note: the following is not a Y2K bug - it's a Y1.9K bug.   Until
	   somebody invents a time machine, I think we can safely disregard
	   it.   This actually works around a stupid Y2K bug that was present
	   in a very early beta release of dhcpd. */
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	tm.tm_year = atoi (val);
	if (tm.tm_year > 1900)
		tm.tm_year -= 1900;

	/* Slash seperating year from month... */
	token = next_token (&val, cfile);
	if (token != SLASH) {
		parse_warn ("expected slash seperating year from month.");
		if (token != SEMI)
			skip_to_semi (cfile);
		return (TIME)0;
	}

	/* Month... */
	token = next_token (&val, cfile);
	if (token != NUMBER) {
		parse_warn ("numeric month expected.");
		if (token != SEMI)
			skip_to_semi (cfile);
		return (TIME)0;
	}
	tm.tm_mon = atoi (val) - 1;

	/* Slash seperating month from day... */
	token = next_token (&val, cfile);
	if (token != SLASH) {
		parse_warn ("expected slash seperating month from day.");
		if (token != SEMI)
			skip_to_semi (cfile);
		return (TIME)0;
	}

	/* Month... */
	token = next_token (&val, cfile);
	if (token != NUMBER) {
		parse_warn ("numeric day of month expected.");
		if (token != SEMI)
			skip_to_semi (cfile);
		return (TIME)0;
	}
	tm.tm_mday = atoi (val);

	/* Hour... */
	token = next_token (&val, cfile);
	if (token != NUMBER) {
		parse_warn ("numeric hour expected.");
		if (token != SEMI)
			skip_to_semi (cfile);
		return (TIME)0;
	}
	tm.tm_hour = atoi (val);

	/* Colon seperating hour from minute... */
	token = next_token (&val, cfile);
	if (token != COLON) {
		parse_warn ("expected colon seperating hour from minute.");
		if (token != SEMI)
			skip_to_semi (cfile);
		return (TIME)0;
	}

	/* Minute... */
	token = next_token (&val, cfile);
	if (token != NUMBER) {
		parse_warn ("numeric minute expected.");
		if (token != SEMI)
			skip_to_semi (cfile);
		return (TIME)0;
	}
	tm.tm_min = atoi (val);

	/* Colon seperating minute from second... */
	token = next_token (&val, cfile);
	if (token != COLON) {
		parse_warn ("expected colon seperating hour from minute.");
		if (token != SEMI)
			skip_to_semi (cfile);
		return (TIME)0;
	}

	/* Minute... */
	token = next_token (&val, cfile);
	if (token != NUMBER) {
		parse_warn ("numeric minute expected.");
		if (token != SEMI)
			skip_to_semi (cfile);
		return (TIME)0;
	}
	tm.tm_sec = atoi (val);
	tm.tm_isdst = 0;

	/* XXX */ /* We assume that mktime does not use tm_yday. */
	tm.tm_yday = 0;

	/* Make sure the date ends in a semicolon... */
	token = next_token (&val, cfile);
	if (token != SEMI) {
		parse_warn ("semicolon expected.");
		skip_to_semi (cfile);
		return 0;
	}

	/* Guess the time value... */
	guess = ((((((365 * (tm.tm_year - 70) +	/* Days in years since '70 */
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		      (tm.tm_year - 69) / 4 +	/* Leap days since '70 */
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		      (tm.tm_mon		/* Days in months this year */
		       ? months [tm.tm_mon - 1]
		       : 0) +
		      (tm.tm_mon > 1 &&		/* Leap day this year */
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		       !((tm.tm_year - 72) & 3)) +
		      tm.tm_mday - 1) * 24) +	/* Day of month */
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		    tm.tm_hour) * 60) +
		  tm.tm_min) * 60) + tm.tm_sec;

	/* This guess could be wrong because of leap seconds or other
	   weirdness we don't know about that the system does.   For
	   now, we're just going to accept the guess, but at some point
	   it might be nice to do a successive approximation here to
	   get an exact value.   Even if the error is small, if the
	   server is restarted frequently (and thus the lease database
	   is reread), the error could accumulate into something
	   significant. */

	return guess;
}
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/*
 * option-name :== IDENTIFIER |
 		   IDENTIFIER . IDENTIFIER
 */

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struct option *parse_option_name (cfile)
	FILE *cfile;
{
	char *val;
	int token;
	char *vendor;
	struct universe *universe;
	struct option *option;

	token = next_token (&val, cfile);
	if (!is_identifier (token)) {
		parse_warn ("expecting identifier after option keyword.");
		if (token != SEMI)
			skip_to_semi (cfile);
		return (struct option *)0;
	}
	vendor = malloc (strlen (val) + 1);
	if (!vendor)
		error ("no memory for vendor information.");
	strcpy (vendor, val);
	token = peek_token (&val, cfile);
	if (token == DOT) {
		/* Go ahead and take the DOT token... */
		token = next_token (&val, cfile);

		/* The next token should be an identifier... */
		token = next_token (&val, cfile);
		if (!is_identifier (token)) {
			parse_warn ("expecting identifier after '.'");
			if (token != SEMI)
				skip_to_semi (cfile);
			return (struct option *)0;
		}

		/* Look up the option name hash table for the specified
		   vendor. */
		universe = ((struct universe *)
			    hash_lookup (&universe_hash,
					 (unsigned char *)vendor, 0));
		/* If it's not there, we can't parse the rest of the
		   declaration. */
		if (!universe) {
			parse_warn ("no vendor named %s.", vendor);
			skip_to_semi (cfile);
			return (struct option *)0;
		}
	} else {
		/* Use the default hash table, which contains all the
		   standard dhcp option names. */
		val = vendor;
		universe = &dhcp_universe;
	}

	/* Look up the actual option info... */
	option = (struct option *)hash_lookup (universe -> hash,
					       (unsigned char *)val, 0);

	/* If we didn't get an option structure, it's an undefined option. */
	if (!option) {
		if (val == vendor)
			parse_warn ("no option named %s", val);
		else
			parse_warn ("no option named %s for vendor %s",
				    val, vendor);
		skip_to_semi (cfile);
		return (struct option *)0;
	}

	/* Free the initial identifier token. */
	free (vendor);
	return option;
}

781 782 783 784 785
/*
 * colon-seperated-hex-list :== NUMBER |
 *				NUMBER COLON colon-seperated-hex-list
 */

786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846
unsigned char *parse_cshl (cfile, plen)
	FILE *cfile;
	int *plen;
{
	char ibuf [128];
	int ilen = 0;
	int tlen = 0;
	struct option_tag *sl = (struct option_tag *)0;
	struct option_tag *next, **last = &sl;
	int token;
	char *val;
	unsigned char *rv, *rvp;

	do {
		token = next_token (&val, cfile);
		if (token != NUMBER && token != NUMBER_OR_NAME) {
			parse_warn ("expecting hexadecimal number.");
			skip_to_semi (cfile);
			for (; sl; sl = next) {
				next = sl -> next;
				dfree (sl, "parse_cshl");
			}
			return (unsigned char *)0;
		}
		if (ilen == sizeof ibuf) {
			next = (struct option_tag *)
				dmalloc (ilen - 1 +
					 sizeof (struct option_tag),
					 "parse_cshl");
			if (!next)
				error ("no memory for string list.");
			memcpy (next -> data, ibuf, ilen);
			*last = next;
			last = &next -> next;
			tlen += ilen;
			ilen = 0;
		}
		convert_num (&ibuf [ilen++], val, 16, 8);

		token = peek_token (&val, cfile);
		if (token != COLON)
			break;
		token = next_token (&val, cfile);
	} while (1);

	rv = dmalloc (tlen + ilen, "parse_cshl");
	if (!rv)
		error ("no memory to store octet data.");
	rvp = rv;
	while (sl) {
		next = sl -> next;
		memcpy (rvp, sl -> data, sizeof ibuf);
		rvp += sizeof ibuf;
		dfree (sl, "parse_cshl");
		sl = next;
	}
	
	memcpy (rvp, ibuf, ilen);
	*plen = ilen + tlen;
	return rv;
}
847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644

/*
 * executable-statements :== executable-statement executable-statements |
 *			     executable-statement
 *
 * executable-statement :==
 *	IF if-statement |
 * 	ADD class-name SEMI |
 *	BREAK SEMI |
 *	OPTION option-parameter SEMI |
 *	SUPERSEDE option-parameter SEMI |
 *	PREPEND option-parameter SEMI |
 *	APPEND option-parameter SEMI
 */

struct executable_statement *parse_executable_statements (cfile, lose)
	FILE *cfile;
	int *lose;
{
	struct executable_statement *head, **next;

	next = &head;
	while ((*next = parse_executable_statement (cfile, lose)))
		next = &((*next) -> next);
	if (!lose)
		return head;
	return (struct executable_statement *)0;
}

struct executable_statement *parse_executable_statement (cfile, lose)
	FILE *cfile;
	int *lose;
{
	int token;
	char *val;
	struct executable_statement *stmt, base;
	struct class *cta;
	struct option *option;

	switch (peek_token (&val, cfile)) {
	      case IF:
		stmt = parse_if_statement (cfile, lose);
		return stmt;
	      case ADD:
		token = next_token (&val, cfile);
		if (token != STRING) {
			parse_warn ("expecting class name.");
			skip_to_semi (cfile);
			*lose = 1;
			return (struct executable_statement *)0;
		}
		cta = find_class (val);
		if (!cta) {
			parse_warn ("unknown class %s.", val);
			skip_to_semi (cfile);
			*lose = 1;
			return (struct executable_statement *)0;
		}
		if (!parse_semi (cfile)) {
			*lose = 1;
			return (struct executable_statement *)0;
		}
		memset (&base, 0, sizeof base);
		base.op = add_statement;
		base.data.add = cta;
		break;

	      case BREAK:
		token = next_token (&val, cfile);
		if (!parse_semi (cfile)) {
			*lose = 1;
			return (struct executable_statement *)0;
		}
		memset (&base, 0, sizeof base);
		base.op = break_statement;
		break;

	      case OPTION:
		token = next_token (&val, cfile);
		option = parse_option_name (cfile);
		if (!option) {
			*lose = 1;
			return (struct executable_statement *)0;
		}
		return parse_option_statement (cfile, 1, option,
					       supersede_option_statement);

	      case DEFAULT:
		token = next_token (&val, cfile);
		option = parse_option_name (cfile);
		if (!option) {
			*lose = 1;
			return (struct executable_statement *)0;
		}
		return parse_option_statement (cfile, 1, option,
					       default_option_statement);

	      case PREPEND:
		token = next_token (&val, cfile);
		option = parse_option_name (cfile);
		if (!option) {
			*lose = 1;
			return (struct executable_statement *)0;
		}
		return parse_option_statement (cfile, 1, option,
					       prepend_option_statement);

	      case APPEND:
		token = next_token (&val, cfile);
		option = parse_option_name (cfile);
		if (!option) {
			*lose = 1;
			return (struct executable_statement *)0;
		}
		return parse_option_statement (cfile, 1, option,
					       append_option_statement);

	      default:
		*lose = 0;
		return (struct executable_statement *)0;
	}

	stmt = ((struct executable_statement *)
		dmalloc (sizeof (struct executable_statement),
			 "parse_executable_statement"));
	if (!stmt)
		error ("no memory for new statement.");
	*stmt = base;
	return stmt;
}

/*
 * if-statement :== boolean-expression LBRACE executable-statements RBRACE
 *						else-statement
 *
 * else-statement :== <null> |
 *		      ELSE LBRACE executable-statements RBRACE |
 *		      ELSE IF if-statement |
 *		      ELSIF if-statement
 */

struct executable_statement *parse_if_statement (cfile, lose)
	FILE *cfile;
	int *lose;
{
	int token;
	char *val;
	struct executable_statement *stmt;
	struct expression *if_condition;
	struct executable_statement *true, *false;

	token = next_token (&val, cfile);
	if_condition = parse_boolean_expression (cfile, lose);
	if (!if_condition) {
		if (!*lose)
			parse_warn ("boolean expression expected.");
		return (struct executable_statement *)0;
	}
	token = next_token (&val, cfile);
	if (token != LBRACE) {
		parse_warn ("left brace expected.");
		skip_to_semi (cfile);
		*lose = 1;
		return (struct executable_statement *)0;
	}
	true = parse_executable_statements (cfile, lose);
	if (*lose)
		return (struct executable_statement *)0;
	token = next_token (&val, cfile);
	if (token != RBRACE) {
		parse_warn ("right brace expected.");
		skip_to_semi (cfile);
		*lose = 1;
		return (struct executable_statement *)0;
	}
	token = peek_token (&val, cfile);
	if (token == ELSE) {
		token = next_token (&val, cfile);
		token = peek_token (&val, cfile);
		if (token == IF) {
			token = next_token (&val, cfile);
			false = parse_if_statement (cfile, lose);
			if (*lose)
				return (struct executable_statement *)0;
		} else if (token != LBRACE) {
			parse_warn ("left brace or if expected.");
			skip_to_semi (cfile);
			*lose = 1;
			return (struct executable_statement *)0;
		} else {
			token = next_token (&val, cfile);
			false = parse_executable_statement (cfile, lose);
			if (*lose)
				return (struct executable_statement *)0;
		}
	} else if (token == ELSIF) {
		token = next_token (&val, cfile);
		false = parse_if_statement (cfile, lose);
		if (*lose)
			return (struct executable_statement *)0;
	} else
		false = (struct executable_statement *)0;
	
	stmt = ((struct executable_statement *)
		dmalloc (sizeof (struct executable_statement),
			 "parse_if_statement"));
	if (!stmt)
		error ("no memory for if statement.");
	memset (stmt, 0, sizeof *stmt);
	stmt -> op = if_statement;
	stmt -> data.ie.expr = if_condition;
	stmt -> data.ie.true = true;
	stmt -> data.ie.false = false;
	return stmt;
}

/*
 * boolean_expression :== CHECK STRING |
 *  			  NOT boolean-expression |
 *			  data-expression EQUAL data-expression |
 *			  boolean-expression AND boolean-expression |
 *			  boolean-expression OR boolean-expression
 */
   			  

struct expression *parse_boolean_expression (cfile, lose)
	FILE *cfile;
	int *lose;
{
	int token;
	char *val;
	struct collection *col;
	struct expression buf, *rv;
	struct expression *left, *right;

	token = peek_token (&val, cfile);

	/* Check for unary operators... */
	switch (token) {
	      case CHECK:
		token = next_token (&val, cfile);
		token = next_token (&val, cfile);
		if (token != STRING) {
			parse_warn ("string expected.");
			skip_to_semi (cfile);
			*lose = 1;
			return (struct expression *)0;
		}
		for (col = collections; col; col = col -> next)
			if (!strcmp (col -> name, val))
				break;
		if (!col) {
			parse_warn ("unknown collection.");
			*lose = 1;
			return (struct expression *)0;
		}
		buf.op = expr_check;
		buf.data.check = col;
		goto have_expr;

	      case NOT:
		token = next_token (&val, cfile);
		buf.op = expr_not;
		buf.data.not = parse_boolean_expression (cfile, lose);
		if (!buf.data.not) {
			if (!*lose) {
				parse_warn ("match expression expected");
				skip_to_semi (cfile);
			}
			*lose = 1;
			return (struct expression *)0;
		}
		goto have_expr;
	}

	/* If we're going to find an expression at this point, it must
	   involve a binary operator seperating two subexpressions. */
	left = parse_data_expression (cfile, lose);
	if (!left)
		return left;
	token = peek_token (&val, cfile);
	switch (token) {
	      case EQUAL:
		buf.op = expr_equal;
		break;
	      case AND:
		buf.op = expr_and;
		break;
	      case OR:
		buf.op = expr_or;
		break;
	      default:
		parse_warn ("Expecting a boolean expression.");
		skip_to_semi (cfile);
		*lose = 1;
		return (struct expression *)0;
	}
	token = next_token (&val, cfile);

	/* Now find the RHS of the expression. */
	right = parse_data_expression (cfile, lose);
	if (!right) {
		if (!*lose) {
			if (buf.op == expr_equal)
				parse_warn ("Expecting a data expression.");
			else
				parse_warn ("Expecting a boolean expression.");
			skip_to_semi (cfile);
		}
		return right;
	}

	/* Store the LHS and RHS. */
	buf.data.equal [0] = left;
	buf.data.equal [1] = right;

      have_expr:
	rv = new_expression ("parse_boolean_expression");
	if (!rv)
		error ("No memory for boolean expression.");
	*rv = buf;
	return rv;
}	

/*
 * data_expression :== SUBSTRING LPAREN data-expression COMMA
 *					numeric-expression COMMA
 *					numeric-expression RPAREN |
 *		       SUFFIX LPAREN data_expression COMMA
 *		       		     numeric-expression |
 *		       OPTION option_name |
 *		       HARDWARE |
 *		       PACKET LPAREN numeric-expression COMMA
 *				     numeric-expression RPAREN |
 *		       STRING |
 *		       colon_seperated_hex_list
 */

struct expression *parse_data_expression (cfile, lose)
	FILE *cfile;
	int *lose;
{
	int token;
	char *val;
	struct collection *col;
	struct expression buf, *rv;
	struct expression *left, *right;
	struct option *option;

	token = peek_token (&val, cfile);

	switch (token) {
	      case SUBSTRING:
		token = next_token (&val, cfile);
		buf.op = expr_substring;

		token = next_token (&val, cfile);
		if (token != LPAREN) {
		      nolparen:
			parse_warn ("left parenthesis expected.");
			*lose = 1;
			return (struct expression *)0;
		}

		rv = parse_data_expression (cfile, lose);
		if (!rv) {
		      nodata:
			parse_warn ("expecting data expression.");
			skip_to_semi (cfile);
			*lose = 1;
			return (struct expression *)0;
		}

		token = next_token (&val, cfile);
		if (token != COMMA) {
		      nocomma:
			parse_warn ("comma expected.");
			*lose = 1;
			return (struct expression *)0;
		}

		left = parse_numeric_expression (cfile, lose);
		if (!left) {
		      nonum:
			if (!*lose) {
				parse_warn ("expecting numeric expression.");
				skip_to_semi (cfile);
				*lose = 1;
			}
			return (struct expression *)0;
		}

		token = next_token (&val, cfile);
		if (token != COMMA)
			goto nocomma;

		right = parse_numeric_expression (cfile, lose);
		if (!right)
			goto nonum;

		token = next_token (&val, cfile);
		if (token != RPAREN) {
		      norparen:
			parse_warn ("right parenthesis expected.");
			*lose = 1;
			return (struct expression *)0;
		}
		return make_substring (rv, left, right);

	      case SUFFIX:
		token = next_token (&val, cfile);
		buf.op = expr_suffix;

		token = next_token (&val, cfile);
		if (token != LPAREN)
			goto nolparen;

		buf.data.suffix.expr = parse_data_expression (cfile, lose);
		if (!buf.data.suffix.expr)
			goto nodata;

		token = next_token (&val, cfile);
		if (token != COMMA)
			goto nocomma;

		buf.data.suffix.len = parse_numeric_expression (cfile, lose);
		if (!buf.data.suffix.len)
			goto nonum;

		token = next_token (&val, cfile);
		if (token != RPAREN)
			goto norparen;
		goto have_expr;

	      case OPTION:
		token = next_token (&val, cfile);
		buf.op = expr_option;
		buf.data.option = parse_option_name (cfile);
		if (!buf.data.option) {
			*lose = 1;
			return (struct expression *)0;
		}
		goto have_expr;

	      case HARDWARE:
		token = next_token (&val, cfile);
		buf.op = expr_hardware;
		goto have_expr;

	      case PACKET:
		token = next_token (&val, cfile);
		buf.op = expr_packet;

		token = next_token (&val, cfile);
		if (token != LPAREN)
			goto nolparen;

		buf.data.packet.offset =
			parse_numeric_expression (cfile, lose);
		if (!buf.data.packet.offset)
			goto nonum;

		token = next_token (&val, cfile);
		if (token != COMMA)
			goto nocomma;

		buf.data.packet.len =
			parse_numeric_expression (cfile, lose);
		if (!buf.data.substring.len)
			goto nonum;

		token = next_token (&val, cfile);
		if (token != RPAREN)
			goto norparen;
		goto have_expr;
		
	      case STRING:
		token = next_token (&val, cfile);
		return make_const_data (val, strlen (val), 1, 1);

	      case NUMBER:
	      case NUMBER_OR_NAME:
		buf.op = expr_const_data;
		memset (&buf.data, 0, sizeof buf.data);
		buf.data.const_data.data =
			parse_cshl (cfile, &buf.data.const_data.len);
		goto have_expr;

	      default:
		return (struct expression *)0;
	}

      have_expr:
	rv = (struct expression *)dmalloc (sizeof (struct expression),
					   "parse_boolean_expression");
	if (!rv)
		error ("No memory for boolean expression.");
	*rv = buf;
	return rv;
}

/*
 * numeric-expression :== EXTRACT_INT LPAREN data-expression
 *					     COMMA number RPAREN |
 *			  NUMBER
 */

struct expression *parse_numeric_expression (cfile, lose)
	FILE *cfile;
	int *lose;
{
	int token;
	char *val;
	struct collection *col;
	struct expression buf, *rv;
	struct expression *left, *right;
	struct option *option;

	token = peek_token (&val, cfile);

	switch (token) {
	      case EXTRACT_INT:
		token = next_token (&val, cfile);	

		token = next_token (&val, cfile);
		if (token != LPAREN) {
			parse_warn ("left parenthesis expected.");
			*lose = 1;
			return (struct expression *)0;
		}

		buf.data.extract_int.expr =
			parse_data_expression (cfile, lose);
		if (!buf.data.extract_int.expr) {
			parse_warn ("expecting data expression.");
			skip_to_semi (cfile);
			*lose = 1;
			return (struct expression *)0;
		}

		token = next_token (&val, cfile);
		if (token != COMMA) {
			parse_warn ("comma expected.");
			*lose = 1;
			return (struct expression *)0;
		}

		token = next_token (&val, cfile);
		if (token != NUMBER) {
			parse_warn ("number expected.");
			*lose = 1;
			return (struct expression *)0;
		}
		buf.data.extract_int.width = (struct expression *)0;
		switch (atoi (val)) {
		      case 8:
			buf.op = expr_extract_int8;
			break;

		      case 16:
			buf.op = expr_extract_int16;
			break;

		      case 32:
			buf.op = expr_extract_int32;
			break;

		      default:
			parse_warn ("unsupported integer size %d", atoi (val));
			*lose = 1;
			skip_to_semi (cfile);
			return (struct expression *)0;
		}

		token = next_token (&val, cfile);
		if (token != RPAREN) {
			parse_warn ("right parenthesis expected.");
			*lose = 1;
			return (struct expression *)0;
		}
		goto have_expr;
	
	      case NUMBER:
		buf.op = expr_const_int;
		buf.data.const_int = atoi (val);
		goto have_expr;

	      default:
		return (struct expression *)0;
	}

      have_expr:
	rv = (struct expression *)dmalloc (sizeof (struct expression),
					   "parse_boolean_expression");
	if (!rv)
		error ("No memory for boolean expression.");
	*rv = buf;
	return rv;
}

/* option-statement :== identifier DOT identifier <syntax> SEMI
		      | identifier <syntax> SEMI

   Option syntax is handled specially through format strings, so it
   would be painful to come up with BNF for it.   However, it always
   starts as above and ends in a SEMI. */

struct executable_statement *parse_option_statement (cfile, lookups,
						     option, op)
	FILE *cfile;
	int lookups;
	struct option *option;
	enum statement_op op;
{
	char *val;
	int token;
	char *fmt;
	struct expression *expr = (struct expression *)0;
	int lose;
	struct executable_statement *stmt;

	token = peek_token (&val, cfile);
	if (token == SEMI) {
		/* Eat the semicolon... */
		token = next_token (&val, cfile);
		expr = make_const_data (0, 0, 0, 0);
		goto done;
	}

	/* See if there's a data expression, and if so, use it rather than
	   the standard format. */
	expr = ((struct expression *)parse_data_expression (cfile, &lose));

	/* Found a data expression, but it was bogus? */
	if (lose)
		return (struct executable_statement *)0;
		
	/* We found one. */
	if (expr)
		goto done;

	/* Parse the option data... */
	do {
		/* Set a flag if this is an array of a simple type (i.e.,
		   not an array of pairs of IP addresses, or something
		   like that. */
		int uniform = option -> format [1] == 'A';

		for (fmt = option -> format; *fmt; fmt++) {
			if (*fmt == 'A')
				break;
			expr = parse_option_token (cfile, fmt,
						   expr, uniform, lookups);
		}
		if (*fmt == 'A') {
			token = peek_token (&val, cfile);
			if (token == COMMA) {
				token = next_token (&val, cfile);
				continue;
			}
			break;
		}
	} while (*fmt == 'A');

      done:
	token = next_token (&val, cfile);
	if (token != SEMI) {
		parse_warn ("semicolon expected.");
		skip_to_semi (cfile);
		return (struct executable_statement *)0;
	}
	stmt = ((struct executable_statement *)
		dmalloc (sizeof *stmt, "parse_option_statement"));
	stmt -> op = op;
	stmt -> data.option = option_cache (expr, option);
	return stmt;
}

struct expression *parse_option_token (cfile, fmt, expr, uniform, lookups)
	FILE *cfile;
	char *fmt;
	struct expression *expr;
	int uniform;
	int lookups;
{
	char *val;
	int token;
	struct expression *t;
	unsigned char buf [4];
	int len;
	unsigned char *ob;
	struct iaddr addr;

	switch (*fmt) {
	      case 'X':
		token = peek_token (&val, cfile);
		if (token == NUMBER_OR_NAME || token == NUMBER) {
			ob = parse_cshl (cfile, &len);
			return make_concat (expr,
					    make_const_data (ob, len, 0, 0));
		} else if (token == STRING) {
			token = next_token (&val, cfile);
			return make_concat (expr,
					    make_const_data ((unsigned char *)
							     val,
							     strlen (val),
							     1, 1));
		} else {
			parse_warn ("expecting string %s.",
				    "or hexadecimal data");
			skip_to_semi (cfile);
			return (struct expression *)0;
		}
		break;
		
	      case 't': /* Text string... */
		token = next_token (&val, cfile);
		if (token != STRING && !is_identifier (token)) {
			parse_warn ("expecting string.");
			if (token != SEMI)
				skip_to_semi (cfile);
			return (struct expression *)0;
		}
		return make_concat (expr,
				    make_const_data ((unsigned char *)
						     val, strlen (val), 1, 1));
		break;
		
	      case 'I': /* IP address or hostname. */
		if (lookups)
			t = parse_ip_addr_or_hostname (cfile, uniform);
		else {
			if (!parse_ip_addr (cfile, &addr))
				return (struct expression *)0;
			t = make_const_data (addr.iabuf, addr.len, 0, 1);
		}
		if (!t)
			return (struct expression *)0;
		return make_concat (expr, t);
		break;
		
	      case 'L': /* Unsigned 32-bit integer... */
	      case 'l':	/* Signed 32-bit integer... */
		token = next_token (&val, cfile);
		if (token != NUMBER) {
		      need_number:
			parse_warn ("expecting number.");
			if (token != SEMI)
				skip_to_semi (cfile);
			return (struct expression *)0;
		}
		convert_num (buf, val, 0, 32);
		return make_concat (expr, make_const_data (buf, 4, 0, 1));
		break;
	      case 's':	/* Signed 16-bit integer. */
	      case 'S':	/* Unsigned 16-bit integer. */
		token = next_token (&val, cfile);
		if (token != NUMBER)
			goto need_number;
		convert_num (buf, val, 0, 16);
		return make_concat (expr, make_const_data (buf, 2, 0, 1));
		break;
	      case 'b':	/* Signed 8-bit integer. */
	      case 'B':	/* Unsigned 8-bit integer. */
		token = next_token (&val, cfile);
		if (token != NUMBER)
			goto need_number;
		convert_num (buf, val, 0, 8);
		return make_concat (expr, make_const_data (buf, 1, 0, 1));
		break;
	      case 'f': /* Boolean flag. */
		token = next_token (&val, cfile);
		if (!is_identifier (token)) {
			parse_warn ("expecting identifier.");
		      bad_flag:
			if (token != SEMI)
				skip_to_semi (cfile);
			return (struct expression *)0;
		}
		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;
		}
		return make_concat (expr, make_const_data (buf, 1, 0, 1));
		break;
	      default:
		warn ("Bad format %c in parse_option_param.",
		      *fmt);
		skip_to_semi (cfile);
		return (struct expression *)0;
	}
}