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dhcpd-pools/src/getdata.c
Sami Kerola e4282e8a3d Version 2.10 
Signed-off-by: Sami Kerola <kerolasa@iki.fi>
2011-07-11 14:09:52 +02:00

402 lines
10 KiB
C
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/*
** Copyright (C) 2006- Sami Kerola <kerolasa@iki.fi>
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#else /* Not STDC_HEADERS */
extern void exit();
extern char *malloc();
#define EXIT_FAILURE 1 /* Failing exit status. */
#define EXIT_SUCCESS 0 /* Successful exit status. */
#endif /* STDC_HEADERS */
#ifdef HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#include <stdio.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#define _XOPEN_SOURCE 600
#include <fcntl.h>
#include <errno.h>
#include "dhcpd-pools.h"
#include "defaults.h"
/* Parse dhcpd.leases file. All performance boosts for this
* function are wellcome */
int parse_leases(void)
{
FILE *dhcpd_leases;
char *line, *ipstring;
struct in_addr inp;
struct stat lease_file_stats;
num_touches = num_leases = num_backups = 0;
dhcpd_leases = fopen(config.dhcpdlease_file, "r");
if (dhcpd_leases == NULL) {
eprintf("parse_leases: %s:", config.dhcpdlease_file);
exit(EXIT_FAILURE);
}
posix_fadvise((long) dhcpd_leases, 0, 0, POSIX_FADV_NOREUSE);
if (errno) {
eprintf("parse_leases: fadvise:");
exit(EXIT_FAILURE);
}
posix_fadvise((long) dhcpd_leases, 0, 0, POSIX_FADV_SEQUENTIAL);
if (errno) {
eprintf("parse_leases: fadvise:");
exit(EXIT_FAILURE);
}
/* I found out that there's one lease address per 300 bytes in
* dhcpd.leases file. Malloc is little bit pessimistic and uses
* 250. If someone has higher density in lease file I'm
* interested to hear about that. */
if (stat(config.dhcpdlease_file, &lease_file_stats)) {
eprintf("parse_leases: %s:", config.dhcpdlease_file);
exit(EXIT_FAILURE);
}
leases =
safe_malloc(sizeof(long int) *
((lease_file_stats.st_size / 250) + MAXLEN));
touches =
safe_malloc((size_t) sizeof(long int) *
((lease_file_stats.st_size / 250) + MAXLEN));
line = safe_malloc(sizeof(long int) * MAXLEN);
ipstring = safe_malloc(sizeof(long int) * MAXLEN);
while (!feof(dhcpd_leases)) {
fgets(line, MAXLEN, dhcpd_leases);
/* It's a lease, save IP */
if (strstr(line, "lease") == line) {
strncpy(ipstring, line, (size_t) MAXLEN);
nth_field(2, ipstring, ipstring);
inet_aton(ipstring, &inp);
}
/* Copy IP to correct array */
else if (strstr(line, "binding state active")) {
leases[num_leases] = htonl(inp.s_addr);
num_leases++;
} else if (strstr(line, " binding state free")) {
touches[num_touches] = htonl(inp.s_addr);
num_touches++;
} else if (strstr(line, " binding state backup")) {
if (num_backups == 0) {
backups =
safe_malloc((size_t) sizeof(long int) *
((lease_file_stats.st_size
/ 250) + MAXLEN));
}
backups[num_backups] = htonl(inp.s_addr);
num_backups++;
}
}
return 0;
}
/* Like strcpy but for field which is separated by white spaces.
* Number of first field is 1 and not 0 like C programs should
* have. Question of semantics, send mail to author if this
* annoys. All performance boosts for this function are well
* come. */
int nth_field(int n, char *dest, const char *src)
{
int i, j = 0, wordn = 0, len;
len = strlen(src);
for (i = 0; i < len; i++) {
if (isspace(src[i])) {
if (!(wordn < n)) {
dest[j] = '\0';
break;
}
j = 0;
} else {
if (j == 0) {
wordn++;
}
if (wordn == n) {
dest[j] = src[i];
}
j++;
}
}
return 0;
}
/* dhcpd.conf interesting words */
int is_interesting_config_clause(char *s)
{
if (strstr(s, "shared-network")) {
return 1;
} else if (strstr(s, "range")) {
return 3;
} else if (strstr(s, "include")) {
return 4;
} else {
return 0;
}
}
/* TODO: This spagetti monster function need to be rewrote at
* least ones. */
char *parse_config(char *config_file, char *current_shared_name,
char *next_free_shared_name,
struct shared_network_t *shared_p)
{
FILE *dhcpd_config;
int i = 0, newclause = true, argument = false, comment =
false, braces = 0, quote = false;
char word[MAXLEN], c;
int braces_shared = 1000;
struct in_addr inp;
struct range_t *range_p;
char *last_shared_name;
last_shared_name = SHARED_NETWORKS_NAMES + shared_net_names;
/* Default place holder for ranges "All networks".
* If this is include file basicly nothing happens. */
shared_p->name = current_shared_name;
/* Open configuration file */
dhcpd_config = fopen(config_file, "r");
if (dhcpd_config == NULL) {
eprintf("parse_config: %s:", config_file);
exit(EXIT_FAILURE);
}
posix_fadvise((long) dhcpd_config, 0, 0, POSIX_FADV_NOREUSE);
if (errno) {
eprintf("parse_config: fadvise:");
exit(EXIT_FAILURE);
}
posix_fadvise((long) dhcpd_config, 0, 0, POSIX_FADV_SEQUENTIAL);
if (errno) {
eprintf("parse_config: fadvise:");
exit(EXIT_FAILURE);
}
/* Very hairy stuff begins. */
while (!feof(dhcpd_config)) {
c = fgetc(dhcpd_config);
/* Certain characters are magical */
switch (c) {
/* Handle comments if they are not quoted */
case '#':
if (quote == false) {
comment = true;
}
continue;
case '"':
if (comment == false) {
quote++;
/* Either one or zero */
quote = quote % 2;
}
continue;
case '\n':
/* New line resets comment section, but not if quoted */
if (quote == false) {
comment = false;
}
break;
case ';':
/* Quoted colon does not mean new clause */
if (quote == true) {
break;
}
if (comment == false && argument != 2
&& argument != 4) {
newclause = true;
i = 0;
} else if (argument == 2) {
/* Range ends to ; and this hair in code make two
* ranges wrote to gether like...
*
* range 10.20.30.40 10.20.30.41;range 10.20.30.42 10.20.30.43;
*
* ...to be interpreted correctly. */
c = ' ';
}
continue;
case '{':
if (quote == true) {
break;
}
if (comment == false) {
braces++;
}
/* i == 0 detects word that ends to brace like:
*
* shared-network DSL{ ... */
if (i == 0) {
newclause = true;
}
continue;
case '}':
if (quote == true) {
break;
}
if (comment == false) {
braces--;
/* End of shared-network */
if (braces_shared == braces) {
current_shared_name =
shared_net_names;
/* TODO: Using 1000 is lame, but works. */
braces_shared = 1000;
shared_p = shared_networks;
}
/* Not literally true, but works for this program */
newclause = true;
}
continue;
default:
break;
}
/* Either inside comment or Nth word of clause. */
if (comment == true
|| (newclause == false && argument == 0)) {
continue;
}
/* Strip white spaces before new clause word. */
if ((newclause == true || argument != 0) && isspace(c)
&& i == 0) {
continue;
}
/* Save to word which clause this is. */
if ((newclause == true || argument != 0)
&& (!isspace(c) || quote == true)) {
word[i] = c;
i++;
/* Long word which is almost causing overflow. Not any of words
* this program is looking for are this long. */
if (i > MAXLEN) {
newclause = false;
i = 0;
continue;
}
}
/* See if clause is something that parser is looking for. */
else if (newclause == true) {
/* Insert string end & set state */
word[i] = '\0';
newclause = false;
i = 0;
argument = is_interesting_config_clause(word);
}
/* words after range, shared-network or include */
else if (argument != 0) {
word[i] = '\0';
newclause = false;
i = 0;
switch (argument) {
case 0:
/* printf ("nothing interesting: %s\n", word); */
argument = 0;
break;
case 1:
/* printf ("shared-network named: %s\n", word); */
strcpy(next_free_shared_name, word);
shared_p =
shared_networks + num_shared_networks;
num_shared_networks++;
shared_p++;
shared_p->name = next_free_shared_name;
shared_p->available = 0;
shared_p->used = 0;
shared_p->touched = 0;
shared_p->backups = 0;
/* Temporary abuse of argument variable */
argument =
strlen(next_free_shared_name) + 1;
if (last_shared_name >
next_free_shared_name + argument) {
next_free_shared_name += argument;
} else {
/* TODO: make this go away by reallocationg more space. */
eprintf
("parse_config: End of shared-network space, increase SHARED_NETWORKS_NAMES and recompile");
exit(EXIT_FAILURE);
}
argument = 0;
break;
case 2:
/* printf ("range 2nd ip: %s\n", word); */
range_p = ranges + num_ranges;
inet_aton(word, &inp);
argument = 0;
range_p->last_ip = htonl(inp.s_addr) + 1;
range_p->count = 0;
range_p->touched = 0;
range_p->backups = 0;
range_p->shared_net = shared_p;
num_ranges++;
if (num_ranges > RANGES) {
eprintf
("parse_config: Range space full! Increase RANGES and recompile.");
exit(EXIT_FAILURE);
}
newclause = true;
break;
case 3:
/* printf ("range 1nd ip: %s\n", word); */
range_p = ranges + num_ranges;
inet_aton(word, &inp);
range_p->first_ip = htonl(inp.s_addr) - 1;
argument = 2;
break;
case 4:
/* printf ("include file: %s\n", word); */
argument = 0;
next_free_shared_name =
parse_config(word, current_shared_name,
next_free_shared_name,
shared_p);
newclause = true;
break;
default:
eprintf
("parse_config: This cannot happen, report a bug!");
exit(EXIT_FAILURE);
}
}
}
return next_free_shared_name;
}
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