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/* Shared library add-on to iptables to add LOG support. */
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <syslog.h>
#include <getopt.h>
#include <iptables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_LOG.h>
#define LOG_DEFAULT_LEVEL LOG_WARNING
/* Function which prints out usage message. */
static void
help(void)
{
printf(
"LOG v%s options:\n"
" --log-level level Level of logging (numeric or see syslog.conf)\n"
" --log-prefix prefix Prefix log messages with this prefix.\n\n"
" --log-tcp-sequence Log TCP sequence numbers.\n\n"
" --log-tcp-options Log TCP options.\n\n"
" --log-ip-options Log IP options.\n\n",
IPTABLES_VERSION);
}
static struct option opts[] = {
{ "log-level", 1, 0, '!' },
{ "log-prefix", 1, 0, '#' },
{ "log-tcp-sequence", 0, 0, '1' },
{ "log-tcp-options", 0, 0, '2' },
{ "log-ip-options", 0, 0, '3' },
{ 0 }
};
/* Initialize the target. */
static void
init(struct ipt_entry_target *t, unsigned int *nfcache)
{
struct ipt_log_info *loginfo = (struct ipt_log_info *)t->data;
loginfo->level = LOG_DEFAULT_LEVEL;
/* Can't cache this */
*nfcache |= NFC_UNKNOWN;
}
struct ipt_log_names {
const char *name;
unsigned int level;
};
static struct ipt_log_names ipt_log_names[]
= { { "alert", LOG_ALERT },
{ "crit", LOG_CRIT },
{ "debug", LOG_DEBUG },
{ "emerg", LOG_EMERG },
{ "error", LOG_ERR }, /* DEPRECATED */
{ "info", LOG_INFO },
{ "notice", LOG_NOTICE },
{ "panic", LOG_EMERG }, /* DEPRECATED */
{ "warning", LOG_WARNING }
};
static u_int8_t
parse_level(const char *level)
{
unsigned int lev = -1;
unsigned int set = 0;
if (string_to_number(level, 0, 7, &lev) == -1) {
unsigned int i = 0;
for (i = 0;
i < sizeof(ipt_log_names) / sizeof(struct ipt_log_names);
i++) {
if (strncasecmp(level, ipt_log_names[i].name,
strlen(level)) == 0) {
if (set++)
exit_error(PARAMETER_PROBLEM,
"log-level `%s' ambiguous",
level);
lev = ipt_log_names[i].level;
}
}
if (!set)
exit_error(PARAMETER_PROBLEM,
"log-level `%s' unknown", level);
}
return (u_int8_t)lev;
}
#define IPT_LOG_OPT_LEVEL 0x01
#define IPT_LOG_OPT_PREFIX 0x02
#define IPT_LOG_OPT_TCPSEQ 0x04
#define IPT_LOG_OPT_TCPOPT 0x08
#define IPT_LOG_OPT_IPOPT 0x10
/* Function which parses command options; returns true if it
ate an option */
static int
parse(int c, char **argv, int invert, unsigned int *flags,
const struct ipt_entry *entry,
struct ipt_entry_target **target)
{
struct ipt_log_info *loginfo = (struct ipt_log_info *)(*target)->data;
switch (c) {
case '!':
if (*flags & IPT_LOG_OPT_LEVEL)
exit_error(PARAMETER_PROBLEM,
"Can't specify --log-level twice");
if (check_inverse(optarg, &invert, NULL, 0))
exit_error(PARAMETER_PROBLEM,
"Unexpected `!' after --log-level");
loginfo->level = parse_level(optarg);
*flags |= IPT_LOG_OPT_LEVEL;
break;
case '#':
if (*flags & IPT_LOG_OPT_PREFIX)
exit_error(PARAMETER_PROBLEM,
"Can't specify --log-prefix twice");
if (check_inverse(optarg, &invert, NULL, 0))
exit_error(PARAMETER_PROBLEM,
"Unexpected `!' after --log-prefix");
if (strlen(optarg) > sizeof(loginfo->prefix) - 1)
exit_error(PARAMETER_PROBLEM,
"Maximum prefix length %u for --log-prefix",
sizeof(loginfo->prefix) - 1);
strcpy(loginfo->prefix, optarg);
*flags |= IPT_LOG_OPT_PREFIX;
break;
case '1':
if (*flags & IPT_LOG_OPT_TCPSEQ)
exit_error(PARAMETER_PROBLEM,
"Can't specify --log-tcp-sequence "
"twice");
loginfo->logflags |= IPT_LOG_TCPSEQ;
*flags |= IPT_LOG_OPT_TCPSEQ;
break;
case '2':
if (*flags & IPT_LOG_OPT_TCPOPT)
exit_error(PARAMETER_PROBLEM,
"Can't specify --log-tcp-options twice");
loginfo->logflags |= IPT_LOG_TCPOPT;
*flags |= IPT_LOG_OPT_TCPOPT;
break;
case '3':
if (*flags & IPT_LOG_OPT_IPOPT)
exit_error(PARAMETER_PROBLEM,
"Can't specify --log-ip-options twice");
loginfo->logflags |= IPT_LOG_IPOPT;
*flags |= IPT_LOG_OPT_IPOPT;
break;
default:
return 0;
}
return 1;
}
/* Final check; nothing. */
static void final_check(unsigned int flags)
{
}
/* Prints out the targinfo. */
static void
print(const struct ipt_ip *ip,
const struct ipt_entry_target *target,
int numeric)
{
const struct ipt_log_info *loginfo
= (const struct ipt_log_info *)target->data;
unsigned int i = 0;
printf("LOG ");
if (numeric)
printf("flags %u level %u ",
loginfo->logflags, loginfo->level);
else {
for (i = 0;
i < sizeof(ipt_log_names) / sizeof(struct ipt_log_names);
i++) {
if (loginfo->level == ipt_log_names[i].level) {
printf("level %s ", ipt_log_names[i].name);
break;
}
}
if (i == sizeof(ipt_log_names) / sizeof(struct ipt_log_names))
printf("UNKNOWN level %u ", loginfo->level);
if (loginfo->logflags & IPT_LOG_TCPSEQ)
printf("tcp-sequence ");
if (loginfo->logflags & IPT_LOG_TCPOPT)
printf("tcp-options ");
if (loginfo->logflags & IPT_LOG_IPOPT)
printf("ip-options ");
if (loginfo->logflags & ~(IPT_LOG_MASK))
printf("unknown-flags ");
}
if (strcmp(loginfo->prefix, "") != 0)
printf("prefix `%s' ", loginfo->prefix);
}
/* Saves the union ipt_targinfo in parsable form to stdout. */
static void
save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
{
const struct ipt_log_info *loginfo
= (const struct ipt_log_info *)target->data;
unsigned int i = 0;
if (strcmp(loginfo->prefix, "") != 0)
printf("--log-prefix \"%s\" ", loginfo->prefix);
if (loginfo->level != LOG_DEFAULT_LEVEL) {
for (i = 0;
i < sizeof(ipt_log_names) / sizeof(struct ipt_log_names);
i++) {
if (loginfo->level == ipt_log_names[i].level) {
printf("--log-level %s ", ipt_log_names[i].name);
break;
}
}
}
if (loginfo->logflags & IPT_LOG_TCPSEQ)
printf("--log-tcp-sequence ");
if (loginfo->logflags & IPT_LOG_TCPOPT)
printf("--log-tcp-options ");
if (loginfo->logflags & IPT_LOG_IPOPT)
printf("--log-ip-options ");
}
static
struct iptables_target log
= { NULL,
"LOG",
IPTABLES_VERSION,
IPT_ALIGN(sizeof(struct ipt_log_info)),
IPT_ALIGN(sizeof(struct ipt_log_info)),
&help,
&init,
&parse,
&final_check,
&print,
&save,
opts
};
void _init(void)
{
register_target(&log);
}
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