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/* $OpenBSD: parse.c,v 1.37 2014/01/21 03:07:50 krw Exp $ */
/* Common parser code for dhcpd and dhclient. */
/*
* Copyright (c) 1995, 1996, 1997, 1998 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 <stdint.h>
#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(FILE *cfile)
{
int token;
int brace_count = 0;
do {
token = peek_token(NULL, cfile);
if (token == '}') {
if (brace_count) {
if (!--brace_count) {
token = next_token(NULL, cfile);
return;
}
} else
return;
} else if (token == '{') {
brace_count++;
} else if (token == ';' && !brace_count) {
token = next_token(NULL, cfile);
return;
} else if (token == '\n') {
/*
* 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(NULL, cfile);
return;
}
token = next_token(NULL, cfile);
} while (token != EOF);
}
int
parse_semi(FILE *cfile)
{
int token;
token = next_token(NULL, cfile);
if (token != ';') {
parse_warn("expecting semicolon.");
skip_to_semi(cfile);
return (0);
}
return (1);
}
/*
* string-parameter :== STRING SEMI
*/
char *
parse_string(FILE *cfile)
{
char *val, *s;
int token;
token = next_token(&val, cfile);
if (token != TOK_STRING) {
parse_warn("filename must be a string");
if (token != ';')
skip_to_semi(cfile);
return (NULL);
}
s = strdup(val);
if (!s)
error("no memory for string %s.", val);
if (!parse_semi(cfile)) {
free(s);
return (NULL);
}
return (s);
}
/* cidr :== ip-address "/" bit-count
* ip-address :== NUMBER [ DOT NUMBER [ DOT NUMBER [ DOT NUMBER ] ] ]
* bit-count :== 0..32
*/
int
parse_cidr(FILE *cfile, unsigned char *cidr)
{
struct in_addr addr;
int token;
int len;
token = '.';
len = 0;
for (token = '.'; token == '.'; token = next_token(NULL, cfile)) {
if (!parse_decimal(cfile, cidr + 1 + len, 'B'))
break;
if (++len == sizeof(addr)) {
token = next_token(NULL, cfile);
break;
}
}
if (!len) {
parse_warn("expecting CIDR subnet.");
skip_to_semi(cfile);
return (0);
} else if (token != '/') {
parse_warn("expecting '/'.");
skip_to_semi(cfile);
return (0);
} else if (!parse_decimal(cfile, cidr, 'B') || *cidr > 32) {
parse_warn("Expecting CIDR prefix length.");
skip_to_semi(cfile);
return (0);
}
return (1);
}
int
parse_ip_addr(FILE *cfile, struct in_addr *addr)
{
struct in_addr buf;
int len, token;
token = '.';
len = 0;
for (token = '.'; token == '.'; token = next_token(NULL, cfile)) {
if (!parse_decimal(cfile, (unsigned char *)&buf + len, 'B'))
break;
if (++len == sizeof(buf))
break;
}
if (len == 4) {
memcpy(addr, &buf, sizeof(*addr));
return (1);
} else if (token != '.') {
parse_warn("expecting '.'.");
skip_to_semi(cfile);
return (0);
} else {
parse_warn("expecting decimal octet.");
skip_to_semi(cfile);
return (0);
}
}
/*
* ETHERNET :== 'ethernet' NUMBER:NUMBER:NUMBER:NUMBER:NUMBER:NUMBER
*/
void
parse_ethernet(FILE *cfile, struct ether_addr *hardware)
{
struct ether_addr buf;
int len, token;
token = next_token(NULL, cfile);
if (token != TOK_ETHERNET) {
parse_warn("expecting 'ethernet'.");
if (token != ';')
skip_to_semi(cfile);
return;
}
len = 0;
for (token = ':'; token == ':'; token = next_token(NULL, cfile)) {
if (!parse_hex(cfile, &buf.ether_addr_octet[len]))
break;
if (++len == sizeof(buf.ether_addr_octet))
break;
}
if (len == 6) {
if (parse_semi(cfile))
memcpy(hardware, &buf, sizeof(*hardware));
} else if (token != ':') {
parse_warn("expecting ':'.");
skip_to_semi(cfile);
} else {
parse_warn("expecting hex octet.");
skip_to_semi(cfile);
}
}
/*
* lease-time :== NUMBER SEMI
*/
void
parse_lease_time(FILE *cfile, time_t *timep)
{
u_int32_t value;
if (!parse_decimal(cfile, (char *)&value, 'L')) {
parse_warn("expecting unsigned 32-bit decimal value.");
skip_to_semi(cfile);
return;
}
*timep = betoh32(value);
parse_semi(cfile);
}
int
parse_decimal(FILE *cfile, unsigned char *buf, char fmt)
{
char *val;
const char *errstr;
int bytes, token;
long long numval, low, high;
token = next_token(&val, cfile);
switch (fmt) {
case 'l': /* Signed 32-bit integer. */
low = INT32_MIN;
high = INT32_MAX;
bytes = 4;
break;
case 'L': /* Unsigned 32-bit integer. */
low = 0;
high = UINT32_MAX;
bytes = 4;
break;
case 'S': /* Unsigned 16-bit integer. */
low = 0;
high = UINT16_MAX;
bytes = 2;
break;
case 'B': /* Unsigned 8-bit integer. */
low = 0;
high = UINT8_MAX;
bytes = 1;
break;
default:
return (0);
}
numval = strtonum(val, low, high, &errstr);
if (errstr)
return (0);
numval = htobe64(numval);
memcpy(buf, (char *)&numval + (sizeof(numval) - bytes), bytes);
return (1);
}
int
parse_hex(FILE *cfile, unsigned char *buf)
{
char *val, *ep;
int token;
unsigned long ulval;
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))
return (0);
buf[0] = ulval;
return (1);
}
/*
* date :== NUMBER NUMBER SLASH NUMBER SLASH NUMBER
* NUMBER COLON NUMBER COLON NUMBER UTC SEMI
*
* Dates are always in UTC; first number is day of week; next is
* year/month/day; next is hours:minutes:seconds on a 24-hour
* clock.
*/
time_t
parse_date(FILE *cfile)
{
struct tm tm;
char timestr[26]; /* "w yyyy/mm/dd hh:mm:ss UTC" */
char *val, *p;
size_t n;
time_t guess;
int token;
memset(timestr, 0, sizeof(timestr));
do {
token = peek_token(NULL, cfile);
switch (token) {
case TOK_NAME:
case TOK_NUMBER:
case '/':
case ':':
token = next_token(&val, cfile);
n = strlcat(timestr, val, sizeof(timestr));
if (n >= sizeof(timestr)) {
/* XXX Will break after year 9999! */
parse_warn("time string too long");
skip_to_semi(cfile);
return (0);
}
break;
case';':
break;
default:
parse_warn("invalid time string");
skip_to_semi(cfile);
return (0);
}
} while (token != ';');
parse_semi(cfile);
memset(&tm, 0, sizeof(tm)); /* 'cuz strptime ignores tm_isdt. */
p = strptime(timestr, DB_TIMEFMT, &tm);
if (p == NULL || *p != '\0') {
p = strptime(timestr, OLD_DB_TIMEFMT, &tm);
if (p == NULL || *p != '\0') {
p = strptime(timestr, BAD_DB_TIMEFMT, &tm);
if (p == NULL || *p != '\0') {
parse_warn("unparseable time string");
return (0);
}
}
}
guess = timegm(&tm);
if (guess == -1) {
parse_warn("time could not be represented");
return (0);
}
return (guess);
}
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