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#include <stdio.h>
#include <string.h>
#define SYSLOG_NAMES
#include <syslog.h>
#include <xtables.h>
#include <linux/netfilter/xt_LOG.h>
#define LOG_DEFAULT_LEVEL LOG_WARNING
enum {
/* make sure the values correspond with XT_LOG_* bit positions */
O_LOG_TCPSEQ = 0,
O_LOG_TCPOPTS,
O_LOG_IPOPTS,
O_LOG_UID,
__O_LOG_NFLOG,
O_LOG_MAC,
O_LOG_LEVEL,
O_LOG_PREFIX,
};
static void LOG_help(void)
{
printf(
"LOG target options:\n"
" --log-level level Level of logging (numeric or see syslog.conf)\n"
" --log-prefix prefix Prefix log messages with this prefix.\n"
" --log-tcp-sequence Log TCP sequence numbers.\n"
" --log-tcp-options Log TCP options.\n"
" --log-ip-options Log IP options.\n"
" --log-uid Log UID owning the local socket.\n"
" --log-macdecode Decode MAC addresses and protocol.\n");
}
#define s struct xt_log_info
static const struct xt_option_entry LOG_opts[] = {
{.name = "log-level", .id = O_LOG_LEVEL, .type = XTTYPE_SYSLOGLEVEL,
.flags = XTOPT_PUT, XTOPT_POINTER(s, level)},
{.name = "log-prefix", .id = O_LOG_PREFIX, .type = XTTYPE_STRING,
.flags = XTOPT_PUT, XTOPT_POINTER(s, prefix), .min = 1},
{.name = "log-tcp-sequence", .id = O_LOG_TCPSEQ, .type = XTTYPE_NONE},
{.name = "log-tcp-options", .id = O_LOG_TCPOPTS, .type = XTTYPE_NONE},
{.name = "log-ip-options", .id = O_LOG_IPOPTS, .type = XTTYPE_NONE},
{.name = "log-uid", .id = O_LOG_UID, .type = XTTYPE_NONE},
{.name = "log-macdecode", .id = O_LOG_MAC, .type = XTTYPE_NONE},
XTOPT_TABLEEND,
};
#undef s
static void LOG_init(struct xt_entry_target *t)
{
struct xt_log_info *loginfo = (void *)t->data;
loginfo->level = LOG_DEFAULT_LEVEL;
}
static void LOG_parse(struct xt_option_call *cb)
{
struct xt_log_info *info = cb->data;
xtables_option_parse(cb);
switch (cb->entry->id) {
case O_LOG_PREFIX:
if (strchr(cb->arg, '\n') != NULL)
xtables_error(PARAMETER_PROBLEM,
"Newlines not allowed in --log-prefix");
break;
case O_LOG_TCPSEQ:
case O_LOG_TCPOPTS:
case O_LOG_IPOPTS:
case O_LOG_UID:
case O_LOG_MAC:
info->logflags |= 1 << cb->entry->id;
break;
}
}
static const char *priority2name(unsigned char level)
{
int i;
for (i = 0; prioritynames[i].c_name; ++i) {
if (level == prioritynames[i].c_val)
return prioritynames[i].c_name;
}
return NULL;
}
static void LOG_print(const void *ip, const struct xt_entry_target *target,
int numeric)
{
const struct xt_log_info *loginfo = (const void *)target->data;
printf(" LOG");
if (numeric)
printf(" flags %u level %u",
loginfo->logflags, loginfo->level);
else {
const char *pname = priority2name(loginfo->level);
if (pname)
printf(" level %s", pname);
else
printf(" UNKNOWN level %u", loginfo->level);
if (loginfo->logflags & XT_LOG_TCPSEQ)
printf(" tcp-sequence");
if (loginfo->logflags & XT_LOG_TCPOPT)
printf(" tcp-options");
if (loginfo->logflags & XT_LOG_IPOPT)
printf(" ip-options");
if (loginfo->logflags & XT_LOG_UID)
printf(" uid");
if (loginfo->logflags & XT_LOG_MACDECODE)
printf(" macdecode");
if (loginfo->logflags & ~(XT_LOG_MASK))
printf(" unknown-flags");
}
if (strcmp(loginfo->prefix, "") != 0)
printf(" prefix \"%s\"", loginfo->prefix);
}
static void LOG_save(const void *ip, const struct xt_entry_target *target)
{
const struct xt_log_info *loginfo = (const void *)target->data;
if (strcmp(loginfo->prefix, "") != 0) {
printf(" --log-prefix");
xtables_save_string(loginfo->prefix);
}
if (loginfo->level != LOG_DEFAULT_LEVEL)
printf(" --log-level %d", loginfo->level);
if (loginfo->logflags & XT_LOG_TCPSEQ)
printf(" --log-tcp-sequence");
if (loginfo->logflags & XT_LOG_TCPOPT)
printf(" --log-tcp-options");
if (loginfo->logflags & XT_LOG_IPOPT)
printf(" --log-ip-options");
if (loginfo->logflags & XT_LOG_UID)
printf(" --log-uid");
if (loginfo->logflags & XT_LOG_MACDECODE)
printf(" --log-macdecode");
}
static int LOG_xlate(struct xt_xlate *xl,
const struct xt_xlate_tg_params *params)
{
const struct xt_log_info *loginfo = (const void *)params->target->data;
const char *pname = priority2name(loginfo->level);
xt_xlate_add(xl, "log");
if (strcmp(loginfo->prefix, "") != 0)
xt_xlate_add(xl, " prefix \"%s\"", loginfo->prefix);
if (loginfo->level != LOG_DEFAULT_LEVEL && pname)
xt_xlate_add(xl, " level %s", pname);
else if (!pname)
return 0;
if ((loginfo->logflags & XT_LOG_MASK) == XT_LOG_MASK) {
xt_xlate_add(xl, " flags all");
} else {
if (loginfo->logflags & (XT_LOG_TCPSEQ | XT_LOG_TCPOPT)) {
const char *delim = " ";
xt_xlate_add(xl, " flags tcp");
if (loginfo->logflags & XT_LOG_TCPSEQ) {
xt_xlate_add(xl, " sequence");
delim = ",";
}
if (loginfo->logflags & XT_LOG_TCPOPT)
xt_xlate_add(xl, "%soptions", delim);
}
if (loginfo->logflags & XT_LOG_IPOPT)
xt_xlate_add(xl, " flags ip options");
if (loginfo->logflags & XT_LOG_UID)
xt_xlate_add(xl, " flags skuid");
if (loginfo->logflags & XT_LOG_MACDECODE)
xt_xlate_add(xl, " flags ether");
}
return 1;
}
static struct xtables_target log_tg_reg = {
.name = "LOG",
.version = XTABLES_VERSION,
.family = NFPROTO_UNSPEC,
.size = XT_ALIGN(sizeof(struct xt_log_info)),
.userspacesize = XT_ALIGN(sizeof(struct xt_log_info)),
.help = LOG_help,
.init = LOG_init,
.print = LOG_print,
.save = LOG_save,
.x6_parse = LOG_parse,
.x6_options = LOG_opts,
.xlate = LOG_xlate,
};
void _init(void)
{
xtables_register_target(&log_tg_reg);
}
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