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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
#ifndef IPT_LOG_UID /* Old kernel */
#define IPT_LOG_UID 0x08 /* Log UID owning local socket */
#undef IPT_LOG_MASK
#define IPT_LOG_MASK 0x0f
#endif
/* Function which prints out usage message. */
static void LOG_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"
" --log-uid Log UID owning the local socket.\n\n",
IPTABLES_VERSION);
}
static const struct option LOG_opts[] = {
{ .name = "log-level", .has_arg = 1, .val = '!' },
{ .name = "log-prefix", .has_arg = 1, .val = '#' },
{ .name = "log-tcp-sequence", .has_arg = 0, .val = '1' },
{ .name = "log-tcp-options", .has_arg = 0, .val = '2' },
{ .name = "log-ip-options", .has_arg = 0, .val = '3' },
{ .name = "log-uid", .has_arg = 0, .val = '4' },
{ .name = NULL }
};
/* Initialize the target. */
static void LOG_init(struct xt_entry_target *t)
{
struct ipt_log_info *loginfo = (struct ipt_log_info *)t->data;
loginfo->level = LOG_DEFAULT_LEVEL;
}
struct ipt_log_names {
const char *name;
unsigned int level;
};
static const struct ipt_log_names ipt_log_names[]
= { { .name = "alert", .level = LOG_ALERT },
{ .name = "crit", .level = LOG_CRIT },
{ .name = "debug", .level = LOG_DEBUG },
{ .name = "emerg", .level = LOG_EMERG },
{ .name = "error", .level = LOG_ERR }, /* DEPRECATED */
{ .name = "info", .level = LOG_INFO },
{ .name = "notice", .level = LOG_NOTICE },
{ .name = "panic", .level = LOG_EMERG }, /* DEPRECATED */
{ .name = "warning", .level = 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
#define IPT_LOG_OPT_UID 0x20
/* Function which parses command options; returns true if it
ate an option */
static int LOG_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry, struct xt_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",
(unsigned int)sizeof(loginfo->prefix) - 1);
if (strlen(optarg) == 0)
exit_error(PARAMETER_PROBLEM,
"No prefix specified for --log-prefix");
if (strlen(optarg) != strlen(strtok(optarg, "\n")))
exit_error(PARAMETER_PROBLEM,
"Newlines not allowed in --log-prefix");
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;
case '4':
if (*flags & IPT_LOG_OPT_UID)
exit_error(PARAMETER_PROBLEM,
"Can't specify --log-uid twice");
loginfo->logflags |= IPT_LOG_UID;
*flags |= IPT_LOG_OPT_UID;
break;
default:
return 0;
}
return 1;
}
/* Prints out the targinfo. */
static void LOG_print(const void *ip, const struct xt_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_UID)
printf("uid ");
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 LOG_save(const void *ip, const struct xt_entry_target *target)
{
const struct ipt_log_info *loginfo
= (const struct ipt_log_info *)target->data;
if (strcmp(loginfo->prefix, "") != 0) {
printf("--log-prefix ");
save_string(loginfo->prefix);
}
if (loginfo->level != LOG_DEFAULT_LEVEL)
printf("--log-level %d ", loginfo->level);
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 ");
if (loginfo->logflags & IPT_LOG_UID)
printf("--log-uid ");
}
static struct iptables_target log_target = {
.name = "LOG",
.version = IPTABLES_VERSION,
.size = IPT_ALIGN(sizeof(struct ipt_log_info)),
.userspacesize = IPT_ALIGN(sizeof(struct ipt_log_info)),
.help = LOG_help,
.init = LOG_init,
.parse = LOG_parse,
.print = LOG_print,
.save = LOG_save,
.extra_opts = LOG_opts,
};
void _init(void)
{
register_target(&log_target);
}
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