![Fabian Frederick](/assets/img/avatar_default.png)
sizeof(char) is always 1. Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
511 lines
11 KiB
C
511 lines
11 KiB
C
#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/proc_fs.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter.h>
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#include <linux/seq_file.h>
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#include <net/protocol.h>
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#include <net/netfilter/nf_log.h>
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#include "nf_internals.h"
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/* Internal logging interface, which relies on the real
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LOG target modules */
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#define NF_LOG_PREFIXLEN 128
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#define NFLOGGER_NAME_LEN 64
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static struct nf_logger __rcu *loggers[NFPROTO_NUMPROTO][NF_LOG_TYPE_MAX] __read_mostly;
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static DEFINE_MUTEX(nf_log_mutex);
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#define nft_log_dereference(logger) \
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rcu_dereference_protected(logger, lockdep_is_held(&nf_log_mutex))
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static struct nf_logger *__find_logger(int pf, const char *str_logger)
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{
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struct nf_logger *log;
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int i;
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for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
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if (loggers[pf][i] == NULL)
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continue;
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log = nft_log_dereference(loggers[pf][i]);
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if (!strncasecmp(str_logger, log->name, strlen(log->name)))
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return log;
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}
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return NULL;
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}
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void nf_log_set(struct net *net, u_int8_t pf, const struct nf_logger *logger)
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{
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const struct nf_logger *log;
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if (pf == NFPROTO_UNSPEC)
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return;
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mutex_lock(&nf_log_mutex);
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log = nft_log_dereference(net->nf.nf_loggers[pf]);
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if (log == NULL)
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rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
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mutex_unlock(&nf_log_mutex);
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}
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EXPORT_SYMBOL(nf_log_set);
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void nf_log_unset(struct net *net, const struct nf_logger *logger)
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{
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int i;
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const struct nf_logger *log;
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mutex_lock(&nf_log_mutex);
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for (i = 0; i < NFPROTO_NUMPROTO; i++) {
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log = nft_log_dereference(net->nf.nf_loggers[i]);
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if (log == logger)
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RCU_INIT_POINTER(net->nf.nf_loggers[i], NULL);
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}
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mutex_unlock(&nf_log_mutex);
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synchronize_rcu();
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}
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EXPORT_SYMBOL(nf_log_unset);
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/* return EEXIST if the same logger is registered, 0 on success. */
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int nf_log_register(u_int8_t pf, struct nf_logger *logger)
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{
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int i;
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int ret = 0;
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if (pf >= ARRAY_SIZE(init_net.nf.nf_loggers))
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return -EINVAL;
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mutex_lock(&nf_log_mutex);
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if (pf == NFPROTO_UNSPEC) {
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for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
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if (rcu_access_pointer(loggers[i][logger->type])) {
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ret = -EEXIST;
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goto unlock;
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}
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}
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for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
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rcu_assign_pointer(loggers[i][logger->type], logger);
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} else {
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if (rcu_access_pointer(loggers[pf][logger->type])) {
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ret = -EEXIST;
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goto unlock;
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}
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rcu_assign_pointer(loggers[pf][logger->type], logger);
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}
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unlock:
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mutex_unlock(&nf_log_mutex);
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return ret;
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}
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EXPORT_SYMBOL(nf_log_register);
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void nf_log_unregister(struct nf_logger *logger)
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{
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int i;
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mutex_lock(&nf_log_mutex);
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for (i = 0; i < NFPROTO_NUMPROTO; i++)
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RCU_INIT_POINTER(loggers[i][logger->type], NULL);
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mutex_unlock(&nf_log_mutex);
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}
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EXPORT_SYMBOL(nf_log_unregister);
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int nf_log_bind_pf(struct net *net, u_int8_t pf,
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const struct nf_logger *logger)
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{
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if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
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return -EINVAL;
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mutex_lock(&nf_log_mutex);
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if (__find_logger(pf, logger->name) == NULL) {
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mutex_unlock(&nf_log_mutex);
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return -ENOENT;
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}
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rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
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mutex_unlock(&nf_log_mutex);
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return 0;
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}
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EXPORT_SYMBOL(nf_log_bind_pf);
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void nf_log_unbind_pf(struct net *net, u_int8_t pf)
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{
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if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
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return;
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mutex_lock(&nf_log_mutex);
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RCU_INIT_POINTER(net->nf.nf_loggers[pf], NULL);
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mutex_unlock(&nf_log_mutex);
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}
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EXPORT_SYMBOL(nf_log_unbind_pf);
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void nf_logger_request_module(int pf, enum nf_log_type type)
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{
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if (loggers[pf][type] == NULL)
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request_module("nf-logger-%u-%u", pf, type);
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}
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EXPORT_SYMBOL_GPL(nf_logger_request_module);
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int nf_logger_find_get(int pf, enum nf_log_type type)
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{
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struct nf_logger *logger;
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int ret = -ENOENT;
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if (rcu_access_pointer(loggers[pf][type]) == NULL)
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request_module("nf-logger-%u-%u", pf, type);
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rcu_read_lock();
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logger = rcu_dereference(loggers[pf][type]);
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if (logger == NULL)
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goto out;
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if (logger && try_module_get(logger->me))
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ret = 0;
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out:
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rcu_read_unlock();
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return ret;
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}
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EXPORT_SYMBOL_GPL(nf_logger_find_get);
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void nf_logger_put(int pf, enum nf_log_type type)
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{
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struct nf_logger *logger;
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BUG_ON(loggers[pf][type] == NULL);
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rcu_read_lock();
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logger = rcu_dereference(loggers[pf][type]);
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module_put(logger->me);
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rcu_read_unlock();
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}
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EXPORT_SYMBOL_GPL(nf_logger_put);
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void nf_log_packet(struct net *net,
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u_int8_t pf,
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unsigned int hooknum,
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const struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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const struct nf_loginfo *loginfo,
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const char *fmt, ...)
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{
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va_list args;
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char prefix[NF_LOG_PREFIXLEN];
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const struct nf_logger *logger;
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rcu_read_lock();
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if (loginfo != NULL)
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logger = rcu_dereference(loggers[pf][loginfo->type]);
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else
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logger = rcu_dereference(net->nf.nf_loggers[pf]);
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if (logger) {
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va_start(args, fmt);
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vsnprintf(prefix, sizeof(prefix), fmt, args);
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va_end(args);
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logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
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}
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rcu_read_unlock();
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}
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EXPORT_SYMBOL(nf_log_packet);
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#define S_SIZE (1024 - (sizeof(unsigned int) + 1))
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struct nf_log_buf {
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unsigned int count;
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char buf[S_SIZE + 1];
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};
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static struct nf_log_buf emergency, *emergency_ptr = &emergency;
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__printf(2, 3) int nf_log_buf_add(struct nf_log_buf *m, const char *f, ...)
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{
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va_list args;
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int len;
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if (likely(m->count < S_SIZE)) {
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va_start(args, f);
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len = vsnprintf(m->buf + m->count, S_SIZE - m->count, f, args);
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va_end(args);
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if (likely(m->count + len < S_SIZE)) {
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m->count += len;
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return 0;
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}
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}
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m->count = S_SIZE;
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printk_once(KERN_ERR KBUILD_MODNAME " please increase S_SIZE\n");
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return -1;
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}
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EXPORT_SYMBOL_GPL(nf_log_buf_add);
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struct nf_log_buf *nf_log_buf_open(void)
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{
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struct nf_log_buf *m = kmalloc(sizeof(*m), GFP_ATOMIC);
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if (unlikely(!m)) {
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local_bh_disable();
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do {
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m = xchg(&emergency_ptr, NULL);
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} while (!m);
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}
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m->count = 0;
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return m;
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}
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EXPORT_SYMBOL_GPL(nf_log_buf_open);
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void nf_log_buf_close(struct nf_log_buf *m)
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{
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m->buf[m->count] = 0;
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printk("%s\n", m->buf);
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if (likely(m != &emergency))
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kfree(m);
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else {
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emergency_ptr = m;
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local_bh_enable();
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}
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}
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EXPORT_SYMBOL_GPL(nf_log_buf_close);
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#ifdef CONFIG_PROC_FS
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static void *seq_start(struct seq_file *seq, loff_t *pos)
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{
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struct net *net = seq_file_net(seq);
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mutex_lock(&nf_log_mutex);
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if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
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return NULL;
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return pos;
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}
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static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
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{
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struct net *net = seq_file_net(s);
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(*pos)++;
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if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
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return NULL;
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return pos;
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}
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static void seq_stop(struct seq_file *s, void *v)
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{
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mutex_unlock(&nf_log_mutex);
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}
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static int seq_show(struct seq_file *s, void *v)
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{
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loff_t *pos = v;
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const struct nf_logger *logger;
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int i;
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struct net *net = seq_file_net(s);
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logger = nft_log_dereference(net->nf.nf_loggers[*pos]);
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if (!logger)
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seq_printf(s, "%2lld NONE (", *pos);
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else
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seq_printf(s, "%2lld %s (", *pos, logger->name);
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if (seq_has_overflowed(s))
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return -ENOSPC;
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for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
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if (loggers[*pos][i] == NULL)
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continue;
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logger = nft_log_dereference(loggers[*pos][i]);
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seq_printf(s, "%s", logger->name);
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if (i == 0 && loggers[*pos][i + 1] != NULL)
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seq_printf(s, ",");
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if (seq_has_overflowed(s))
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return -ENOSPC;
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}
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seq_printf(s, ")\n");
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if (seq_has_overflowed(s))
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return -ENOSPC;
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return 0;
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}
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static const struct seq_operations nflog_seq_ops = {
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.start = seq_start,
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.next = seq_next,
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.stop = seq_stop,
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.show = seq_show,
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};
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static int nflog_open(struct inode *inode, struct file *file)
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{
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return seq_open_net(inode, file, &nflog_seq_ops,
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sizeof(struct seq_net_private));
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}
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static const struct file_operations nflog_file_ops = {
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.owner = THIS_MODULE,
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.open = nflog_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release_net,
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};
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#endif /* PROC_FS */
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#ifdef CONFIG_SYSCTL
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static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
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static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
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static int nf_log_proc_dostring(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp, loff_t *ppos)
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{
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const struct nf_logger *logger;
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char buf[NFLOGGER_NAME_LEN];
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size_t size = *lenp;
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int r = 0;
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int tindex = (unsigned long)table->extra1;
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struct net *net = current->nsproxy->net_ns;
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if (write) {
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if (size > sizeof(buf))
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size = sizeof(buf);
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if (copy_from_user(buf, buffer, size))
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return -EFAULT;
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if (!strcmp(buf, "NONE")) {
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nf_log_unbind_pf(net, tindex);
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return 0;
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}
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mutex_lock(&nf_log_mutex);
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logger = __find_logger(tindex, buf);
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if (logger == NULL) {
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mutex_unlock(&nf_log_mutex);
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return -ENOENT;
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}
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rcu_assign_pointer(net->nf.nf_loggers[tindex], logger);
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mutex_unlock(&nf_log_mutex);
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} else {
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mutex_lock(&nf_log_mutex);
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logger = nft_log_dereference(net->nf.nf_loggers[tindex]);
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if (!logger)
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table->data = "NONE";
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else
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table->data = logger->name;
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r = proc_dostring(table, write, buffer, lenp, ppos);
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mutex_unlock(&nf_log_mutex);
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}
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return r;
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}
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static int netfilter_log_sysctl_init(struct net *net)
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{
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int i;
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struct ctl_table *table;
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table = nf_log_sysctl_table;
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if (!net_eq(net, &init_net)) {
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table = kmemdup(nf_log_sysctl_table,
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sizeof(nf_log_sysctl_table),
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GFP_KERNEL);
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if (!table)
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goto err_alloc;
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} else {
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for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
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snprintf(nf_log_sysctl_fnames[i],
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3, "%d", i);
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nf_log_sysctl_table[i].procname =
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nf_log_sysctl_fnames[i];
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nf_log_sysctl_table[i].data = NULL;
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nf_log_sysctl_table[i].maxlen = NFLOGGER_NAME_LEN;
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nf_log_sysctl_table[i].mode = 0644;
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nf_log_sysctl_table[i].proc_handler =
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nf_log_proc_dostring;
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nf_log_sysctl_table[i].extra1 =
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(void *)(unsigned long) i;
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}
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}
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net->nf.nf_log_dir_header = register_net_sysctl(net,
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"net/netfilter/nf_log",
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table);
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if (!net->nf.nf_log_dir_header)
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goto err_reg;
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return 0;
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err_reg:
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if (!net_eq(net, &init_net))
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kfree(table);
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err_alloc:
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return -ENOMEM;
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}
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static void netfilter_log_sysctl_exit(struct net *net)
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{
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struct ctl_table *table;
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table = net->nf.nf_log_dir_header->ctl_table_arg;
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unregister_net_sysctl_table(net->nf.nf_log_dir_header);
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if (!net_eq(net, &init_net))
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kfree(table);
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}
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#else
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static int netfilter_log_sysctl_init(struct net *net)
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{
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return 0;
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}
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static void netfilter_log_sysctl_exit(struct net *net)
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{
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}
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#endif /* CONFIG_SYSCTL */
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static int __net_init nf_log_net_init(struct net *net)
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{
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int ret = -ENOMEM;
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#ifdef CONFIG_PROC_FS
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if (!proc_create("nf_log", S_IRUGO,
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net->nf.proc_netfilter, &nflog_file_ops))
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return ret;
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#endif
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ret = netfilter_log_sysctl_init(net);
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if (ret < 0)
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goto out_sysctl;
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return 0;
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out_sysctl:
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#ifdef CONFIG_PROC_FS
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remove_proc_entry("nf_log", net->nf.proc_netfilter);
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#endif
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return ret;
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}
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static void __net_exit nf_log_net_exit(struct net *net)
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{
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netfilter_log_sysctl_exit(net);
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#ifdef CONFIG_PROC_FS
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remove_proc_entry("nf_log", net->nf.proc_netfilter);
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#endif
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}
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static struct pernet_operations nf_log_net_ops = {
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.init = nf_log_net_init,
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.exit = nf_log_net_exit,
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};
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int __init netfilter_log_init(void)
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{
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return register_pernet_subsys(&nf_log_net_ops);
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}
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