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[NETFILTER]: split net/core/netfilter.c into net/netfilter/*.c

Browse source 
This patch doesn't introduce any code changes, but merely splits the
core netfilter code into four separate files.  It also moves it from
it's old location in net/core/ to the recently-created net/netfilter/
directory.

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Harald Welte 2005-08-09 20:21:49 -07:00 • committed by David S. Miller
parent 210a9ebef2
commit f6ebe77f95
8 changed files with 829 additions and 738 deletions
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1
net/core/Makefile
View file

@ -12,7 +12,6 @@ obj-y += dev.o ethtool.o dev_mcast.o dst.o \
obj-$(CONFIG_XFRM) += flow.o
obj-$(CONFIG_SYSFS) += net-sysfs.o
obj-$(CONFIG_NETFILTER) += netfilter.o
obj-$(CONFIG_NET_DIVERT) += dv.o
obj-$(CONFIG_NET_PKTGEN) += pktgen.o
obj-$(CONFIG_NET_RADIO) += wireless.o

737
net/core/netfilter.c
View file

@ -1,737 +0,0 @@
/* netfilter.c: look after the filters for various protocols.
* Heavily influenced by the old firewall.c by David Bonn and Alan Cox.
*
* Thanks to Rob `CmdrTaco' Malda for not influencing this code in any
* way.
*
* Rusty Russell (C)2000 -- This code is GPL.
*
* February 2000: Modified by James Morris to have 1 queue per protocol.
* 15-Mar-2000: Added NF_REPEAT --RR.
* 08-May-2003: Internal logging interface added by Jozsef Kadlecsik.
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/netfilter.h>
#include <net/protocol.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/wait.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/if.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/proc_fs.h>
#include <net/sock.h>
/* In this code, we can be waiting indefinitely for userspace to
* service a packet if a hook returns NF_QUEUE. We could keep a count
* of skbuffs queued for userspace, and not deregister a hook unless
* this is zero, but that sucks. Now, we simply check when the
* packets come back: if the hook is gone, the packet is discarded. */
#ifdef CONFIG_NETFILTER_DEBUG
#define NFDEBUG(format, args...) printk(format , ## args)
#else
#define NFDEBUG(format, args...)
#endif
/* Sockopts only registered and called from user context, so
net locking would be overkill. Also, [gs]etsockopt calls may
sleep. */
static DECLARE_MUTEX(nf_sockopt_mutex);
struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
static LIST_HEAD(nf_sockopts);
static DEFINE_SPINLOCK(nf_hook_lock);
/*
* A queue handler may be registered for each protocol. Each is protected by
* long term mutex. The handler must provide an an outfn() to accept packets
* for queueing and must reinject all packets it receives, no matter what.
*/
static struct nf_queue_handler_t {
nf_queue_outfn_t outfn;
void *data;
} queue_handler[NPROTO];
static struct nf_queue_rerouter *queue_rerouter;
static DEFINE_RWLOCK(queue_handler_lock);
int nf_register_hook(struct nf_hook_ops *reg)
{
struct list_head *i;
spin_lock_bh(&nf_hook_lock);
list_for_each(i, &nf_hooks[reg->pf][reg->hooknum]) {
if (reg->priority < ((struct nf_hook_ops *)i)->priority)
break;
}
list_add_rcu(&reg->list, i->prev);
spin_unlock_bh(&nf_hook_lock);
synchronize_net();
return 0;
}
void nf_unregister_hook(struct nf_hook_ops *reg)
{
spin_lock_bh(&nf_hook_lock);
list_del_rcu(&reg->list);
spin_unlock_bh(&nf_hook_lock);
synchronize_net();
}
/* Do exclusive ranges overlap? */
static inline int overlap(int min1, int max1, int min2, int max2)
{
return max1 > min2 && min1 < max2;
}
/* Functions to register sockopt ranges (exclusive). */
int nf_register_sockopt(struct nf_sockopt_ops *reg)
{
struct list_head *i;
int ret = 0;
if (down_interruptible(&nf_sockopt_mutex) != 0)
return -EINTR;
list_for_each(i, &nf_sockopts) {
struct nf_sockopt_ops *ops = (struct nf_sockopt_ops *)i;
if (ops->pf == reg->pf
&& (overlap(ops->set_optmin, ops->set_optmax,
reg->set_optmin, reg->set_optmax)
|| overlap(ops->get_optmin, ops->get_optmax,
reg->get_optmin, reg->get_optmax))) {
NFDEBUG("nf_sock overlap: %u-%u/%u-%u v %u-%u/%u-%u\n",
ops->set_optmin, ops->set_optmax,
ops->get_optmin, ops->get_optmax,
reg->set_optmin, reg->set_optmax,
reg->get_optmin, reg->get_optmax);
ret = -EBUSY;
goto out;
}
}
list_add(&reg->list, &nf_sockopts);
out:
up(&nf_sockopt_mutex);
return ret;
}
void nf_unregister_sockopt(struct nf_sockopt_ops *reg)
{
/* No point being interruptible: we're probably in cleanup_module() */
restart:
down(&nf_sockopt_mutex);
if (reg->use != 0) {
/* To be woken by nf_sockopt call... */
/* FIXME: Stuart Young's name appears gratuitously. */
set_current_state(TASK_UNINTERRUPTIBLE);
reg->cleanup_task = current;
up(&nf_sockopt_mutex);
schedule();
goto restart;
}
list_del(&reg->list);
up(&nf_sockopt_mutex);
}
/* Call get/setsockopt() */
static int nf_sockopt(struct sock *sk, int pf, int val,
char __user *opt, int *len, int get)
{
struct list_head *i;
struct nf_sockopt_ops *ops;
int ret;
if (down_interruptible(&nf_sockopt_mutex) != 0)
return -EINTR;
list_for_each(i, &nf_sockopts) {
ops = (struct nf_sockopt_ops *)i;
if (ops->pf == pf) {
if (get) {
if (val >= ops->get_optmin
&& val < ops->get_optmax) {
ops->use++;
up(&nf_sockopt_mutex);
ret = ops->get(sk, val, opt, len);
goto out;
}
} else {
if (val >= ops->set_optmin
&& val < ops->set_optmax) {
ops->use++;
up(&nf_sockopt_mutex);
ret = ops->set(sk, val, opt, *len);
goto out;
}
}
}
}
up(&nf_sockopt_mutex);
return -ENOPROTOOPT;
out:
down(&nf_sockopt_mutex);
ops->use--;
if (ops->cleanup_task)
wake_up_process(ops->cleanup_task);
up(&nf_sockopt_mutex);
return ret;
}
int nf_setsockopt(struct sock *sk, int pf, int val, char __user *opt,
int len)
{
return nf_sockopt(sk, pf, val, opt, &len, 0);
}
int nf_getsockopt(struct sock *sk, int pf, int val, char __user *opt, int *len)
{
return nf_sockopt(sk, pf, val, opt, len, 1);
}
static unsigned int nf_iterate(struct list_head *head,
struct sk_buff **skb,
int hook,
const struct net_device *indev,
const struct net_device *outdev,
struct list_head **i,
int (*okfn)(struct sk_buff *),
int hook_thresh)
{
unsigned int verdict;
/*
* The caller must not block between calls to this
* function because of risk of continuing from deleted element.
*/
list_for_each_continue_rcu(*i, head) {
struct nf_hook_ops *elem = (struct nf_hook_ops *)*i;
if (hook_thresh > elem->priority)
continue;
/* Optimization: we don't need to hold module
reference here, since function can't sleep. --RR */
verdict = elem->hook(hook, skb, indev, outdev, okfn);
if (verdict != NF_ACCEPT) {
#ifdef CONFIG_NETFILTER_DEBUG
if (unlikely((verdict & NF_VERDICT_MASK)
> NF_MAX_VERDICT)) {
NFDEBUG("Evil return from %p(%u).\n",
elem->hook, hook);
continue;
}
#endif
if (verdict != NF_REPEAT)
return verdict;
*i = (*i)->prev;
}
}
return NF_ACCEPT;
}
int nf_register_queue_handler(int pf, nf_queue_outfn_t outfn, void *data)
{
int ret;
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
if (queue_handler[pf].outfn)
ret = -EBUSY;
else {
queue_handler[pf].outfn = outfn;
queue_handler[pf].data = data;
ret = 0;
}
write_unlock_bh(&queue_handler_lock);
return ret;
}
/* The caller must flush their queue before this */
int nf_unregister_queue_handler(int pf)
{
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
queue_handler[pf].outfn = NULL;
queue_handler[pf].data = NULL;
write_unlock_bh(&queue_handler_lock);
return 0;
}
int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer)
{
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
memcpy(&queue_rerouter[pf], rer, sizeof(queue_rerouter[pf]));
write_unlock_bh(&queue_handler_lock);
return 0;
}
int nf_unregister_queue_rerouter(int pf)
{
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
memset(&queue_rerouter[pf], 0, sizeof(queue_rerouter[pf]));
write_unlock_bh(&queue_handler_lock);
return 0;
}
void nf_unregister_queue_handlers(nf_queue_outfn_t outfn)
{
int pf;
write_lock_bh(&queue_handler_lock);
for (pf = 0; pf < NPROTO; pf++) {
if (queue_handler[pf].outfn == outfn) {
queue_handler[pf].outfn = NULL;
queue_handler[pf].data = NULL;
}
}
write_unlock_bh(&queue_handler_lock);
}
/*
* Any packet that leaves via this function must come back
* through nf_reinject().
*/
static int nf_queue(struct sk_buff **skb,
struct list_head *elem,
int pf, unsigned int hook,
struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct sk_buff *),
unsigned int queuenum)
{
int status;
struct nf_info *info;
#ifdef CONFIG_BRIDGE_NETFILTER
struct net_device *physindev = NULL;
struct net_device *physoutdev = NULL;
#endif
/* QUEUE == DROP if noone is waiting, to be safe. */
read_lock(&queue_handler_lock);
if (!queue_handler[pf].outfn) {
read_unlock(&queue_handler_lock);
kfree_skb(*skb);
return 1;
}
info = kmalloc(sizeof(*info)+queue_rerouter[pf].rer_size, GFP_ATOMIC);
if (!info) {
if (net_ratelimit())
printk(KERN_ERR "OOM queueing packet %p\n",
*skb);
read_unlock(&queue_handler_lock);
kfree_skb(*skb);
return 1;
}
*info = (struct nf_info) {
(struct nf_hook_ops *)elem, pf, hook, indev, outdev, okfn };
/* If it's going away, ignore hook. */
if (!try_module_get(info->elem->owner)) {
read_unlock(&queue_handler_lock);
kfree(info);
return 0;
}
/* Bump dev refs so they don't vanish while packet is out */
if (indev) dev_hold(indev);
if (outdev) dev_hold(outdev);
#ifdef CONFIG_BRIDGE_NETFILTER
if ((*skb)->nf_bridge) {
physindev = (*skb)->nf_bridge->physindev;
if (physindev) dev_hold(physindev);
physoutdev = (*skb)->nf_bridge->physoutdev;
if (physoutdev) dev_hold(physoutdev);
}
#endif
if (queue_rerouter[pf].save)
queue_rerouter[pf].save(*skb, info);
status = queue_handler[pf].outfn(*skb, info, queuenum,
queue_handler[pf].data);
if (status >= 0 && queue_rerouter[pf].reroute)
status = queue_rerouter[pf].reroute(skb, info);
read_unlock(&queue_handler_lock);
if (status < 0) {
/* James M doesn't say fuck enough. */
if (indev) dev_put(indev);
if (outdev) dev_put(outdev);
#ifdef CONFIG_BRIDGE_NETFILTER
if (physindev) dev_put(physindev);
if (physoutdev) dev_put(physoutdev);
#endif
module_put(info->elem->owner);
kfree(info);
kfree_skb(*skb);
return 1;
}
return 1;
}
/* Returns 1 if okfn() needs to be executed by the caller,
* -EPERM for NF_DROP, 0 otherwise. */
int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct sk_buff *),
int hook_thresh)
{
struct list_head *elem;
unsigned int verdict;
int ret = 0;
/* We may already have this, but read-locks nest anyway */
rcu_read_lock();
elem = &nf_hooks[pf][hook];
next_hook:
verdict = nf_iterate(&nf_hooks[pf][hook], pskb, hook, indev,
outdev, &elem, okfn, hook_thresh);
if (verdict == NF_ACCEPT || verdict == NF_STOP) {
ret = 1;
goto unlock;
} else if (verdict == NF_DROP) {
kfree_skb(*pskb);
ret = -EPERM;
} else if ((verdict & NF_VERDICT_MASK) == NF_QUEUE) {
NFDEBUG("nf_hook: Verdict = QUEUE.\n");
if (!nf_queue(pskb, elem, pf, hook, indev, outdev, okfn,
verdict >> NF_VERDICT_BITS))
goto next_hook;
}
unlock:
rcu_read_unlock();
return ret;
}
void nf_reinject(struct sk_buff *skb, struct nf_info *info,
unsigned int verdict)
{
struct list_head *elem = &info->elem->list;
struct list_head *i;
rcu_read_lock();
/* Release those devices we held, or Alexey will kill me. */
if (info->indev) dev_put(info->indev);
if (info->outdev) dev_put(info->outdev);
#ifdef CONFIG_BRIDGE_NETFILTER
if (skb->nf_bridge) {
if (skb->nf_bridge->physindev)
dev_put(skb->nf_bridge->physindev);
if (skb->nf_bridge->physoutdev)
dev_put(skb->nf_bridge->physoutdev);
}
#endif
/* Drop reference to owner of hook which queued us. */
module_put(info->elem->owner);
list_for_each_rcu(i, &nf_hooks[info->pf][info->hook]) {
if (i == elem)
break;
}
if (elem == &nf_hooks[info->pf][info->hook]) {
/* The module which sent it to userspace is gone. */
NFDEBUG("%s: module disappeared, dropping packet.\n",
__FUNCTION__);
verdict = NF_DROP;
}
/* Continue traversal iff userspace said ok... */
if (verdict == NF_REPEAT) {
elem = elem->prev;
verdict = NF_ACCEPT;
}
if (verdict == NF_ACCEPT) {
next_hook:
verdict = nf_iterate(&nf_hooks[info->pf][info->hook],
&skb, info->hook,
info->indev, info->outdev, &elem,
info->okfn, INT_MIN);
}
switch (verdict & NF_VERDICT_MASK) {
case NF_ACCEPT:
info->okfn(skb);
break;
case NF_QUEUE:
if (!nf_queue(&skb, elem, info->pf, info->hook,
info->indev, info->outdev, info->okfn,
verdict >> NF_VERDICT_BITS))
goto next_hook;
break;
}
rcu_read_unlock();
if (verdict == NF_DROP)
kfree_skb(skb);
kfree(info);
return;
}
int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len)
{
struct sk_buff *nskb;
if (writable_len > (*pskb)->len)
return 0;
/* Not exclusive use of packet? Must copy. */
if (skb_shared(*pskb) || skb_cloned(*pskb))
goto copy_skb;
return pskb_may_pull(*pskb, writable_len);
copy_skb:
nskb = skb_copy(*pskb, GFP_ATOMIC);
if (!nskb)
return 0;
BUG_ON(skb_is_nonlinear(nskb));
/* Rest of kernel will get very unhappy if we pass it a
suddenly-orphaned skbuff */
if ((*pskb)->sk)
skb_set_owner_w(nskb, (*pskb)->sk);
kfree_skb(*pskb);
*pskb = nskb;
return 1;
}
EXPORT_SYMBOL(skb_make_writable);
/* Internal logging interface, which relies on the real
LOG target modules */
#define NF_LOG_PREFIXLEN 128
static struct nf_logger *nf_logging[NPROTO]; /* = NULL */
static DEFINE_SPINLOCK(nf_log_lock);
int nf_log_register(int pf, struct nf_logger *logger)
{
int ret = -EBUSY;
/* Any setup of logging members must be done before
* substituting pointer. */
spin_lock(&nf_log_lock);
if (!nf_logging[pf]) {
rcu_assign_pointer(nf_logging[pf], logger);
ret = 0;
}
spin_unlock(&nf_log_lock);
return ret;
}
void nf_log_unregister_pf(int pf)
{
spin_lock(&nf_log_lock);
nf_logging[pf] = NULL;
spin_unlock(&nf_log_lock);
/* Give time to concurrent readers. */
synchronize_net();
}
void nf_log_unregister_logger(struct nf_logger *logger)
{
int i;
spin_lock(&nf_log_lock);
for (i = 0; i < NPROTO; i++) {
if (nf_logging[i] == logger)
nf_logging[i] = NULL;
}
spin_unlock(&nf_log_lock);
synchronize_net();
}
void nf_log_packet(int pf,
unsigned int hooknum,
const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
struct nf_loginfo *loginfo,
const char *fmt, ...)
{
va_list args;
char prefix[NF_LOG_PREFIXLEN];
struct nf_logger *logger;
rcu_read_lock();
logger = rcu_dereference(nf_logging[pf]);
if (logger) {
va_start(args, fmt);
vsnprintf(prefix, sizeof(prefix), fmt, args);
va_end(args);
/* We must read logging before nf_logfn[pf] */
logger->logfn(pf, hooknum, skb, in, out, loginfo, prefix);
} else if (net_ratelimit()) {
printk(KERN_WARNING "nf_log_packet: can\'t log since "
"no backend logging module loaded in! Please either "
"load one, or disable logging explicitly\n");
}
rcu_read_unlock();
}
EXPORT_SYMBOL(nf_log_register);
EXPORT_SYMBOL(nf_log_unregister_pf);
EXPORT_SYMBOL(nf_log_unregister_logger);
EXPORT_SYMBOL(nf_log_packet);
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *proc_net_netfilter;
EXPORT_SYMBOL(proc_net_netfilter);
static void *seq_start(struct seq_file *seq, loff_t *pos)
{
rcu_read_lock();
if (*pos >= NPROTO)
return NULL;
return pos;
}
static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
{
(*pos)++;
if (*pos >= NPROTO)
return NULL;
return pos;
}
static void seq_stop(struct seq_file *s, void *v)
{
rcu_read_unlock();
}
static int seq_show(struct seq_file *s, void *v)
{
loff_t *pos = v;
const struct nf_logger *logger;
logger = rcu_dereference(nf_logging[*pos]);
if (!logger)
return seq_printf(s, "%2lld NONE\n", *pos);
return seq_printf(s, "%2lld %s\n", *pos, logger->name);
}
static struct seq_operations nflog_seq_ops = {
.start = seq_start,
.next = seq_next,
.stop = seq_stop,
.show = seq_show,
};
static int nflog_open(struct inode *inode, struct file *file)
{
return seq_open(file, &nflog_seq_ops);
}
static struct file_operations nflog_file_ops = {
.owner = THIS_MODULE,
.open = nflog_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#endif /* PROC_FS */
/* This does not belong here, but locally generated errors need it if connection
tracking in use: without this, connection may not be in hash table, and hence
manufactured ICMP or RST packets will not be associated with it. */
void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb)
{
void (*attach)(struct sk_buff *, struct sk_buff *);
if (skb->nfct && (attach = ip_ct_attach) != NULL) {
mb(); /* Just to be sure: must be read before executing this */
attach(new, skb);
}
}
void __init netfilter_init(void)
{
int i, h;
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *pde;
#endif
queue_rerouter = kmalloc(NPROTO * sizeof(struct nf_queue_rerouter),
GFP_KERNEL);
if (!queue_rerouter)
panic("netfilter: cannot allocate queue rerouter array\n");
memset(queue_rerouter, 0, NPROTO * sizeof(struct nf_queue_rerouter));
for (i = 0; i < NPROTO; i++) {
for (h = 0; h < NF_MAX_HOOKS; h++)
INIT_LIST_HEAD(&nf_hooks[i][h]);
}
#ifdef CONFIG_PROC_FS
proc_net_netfilter = proc_mkdir("netfilter", proc_net);
if (!proc_net_netfilter)
panic("cannot create netfilter proc entry");
pde = create_proc_entry("nf_log", S_IRUGO, proc_net_netfilter);
if (!pde)
panic("cannot create /proc/net/netfilter/nf_log");
pde->proc_fops = &nflog_file_ops;
#endif
}
EXPORT_SYMBOL(ip_ct_attach);
EXPORT_SYMBOL(nf_ct_attach);
EXPORT_SYMBOL(nf_getsockopt);
EXPORT_SYMBOL(nf_hook_slow);
EXPORT_SYMBOL(nf_hooks);
EXPORT_SYMBOL(nf_register_hook);
EXPORT_SYMBOL(nf_register_queue_handler);
EXPORT_SYMBOL(nf_register_sockopt);
EXPORT_SYMBOL(nf_reinject);
EXPORT_SYMBOL(nf_setsockopt);
EXPORT_SYMBOL(nf_unregister_hook);
EXPORT_SYMBOL(nf_unregister_queue_handler);
EXPORT_SYMBOL_GPL(nf_unregister_queue_handlers);
EXPORT_SYMBOL_GPL(nf_register_queue_rerouter);
EXPORT_SYMBOL_GPL(nf_unregister_queue_rerouter);
EXPORT_SYMBOL(nf_unregister_sockopt);

4
net/netfilter/Makefile
View file

@ -1,3 +1,7 @@
netfilter-objs := core.o nf_log.o nf_queue.o nf_sockopt.o
obj-$(CONFIG_NETFILTER) = netfilter.o
obj-$(CONFIG_NETFILTER_NETLINK) += nfnetlink.o
obj-$(CONFIG_NETFILTER_NETLINK_QUEUE) += nfnetlink_queue.o
obj-$(CONFIG_NETFILTER_NETLINK_LOG) += nfnetlink_log.o

216
net/netfilter/core.c Normal file
View file

@ -0,0 +1,216 @@
/* netfilter.c: look after the filters for various protocols.
* Heavily influenced by the old firewall.c by David Bonn and Alan Cox.
*
* Thanks to Rob `CmdrTaco' Malda for not influencing this code in any
* way.
*
* Rusty Russell (C)2000 -- This code is GPL.
*
* February 2000: Modified by James Morris to have 1 queue per protocol.
* 15-Mar-2000: Added NF_REPEAT --RR.
* 08-May-2003: Internal logging interface added by Jozsef Kadlecsik.
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/netfilter.h>
#include <net/protocol.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/wait.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/if.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/proc_fs.h>
#include <net/sock.h>
#include "nf_internals.h"
/* In this code, we can be waiting indefinitely for userspace to
* service a packet if a hook returns NF_QUEUE. We could keep a count
* of skbuffs queued for userspace, and not deregister a hook unless
* this is zero, but that sucks. Now, we simply check when the
* packets come back: if the hook is gone, the packet is discarded. */
struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
EXPORT_SYMBOL(nf_hooks);
static DEFINE_SPINLOCK(nf_hook_lock);
int nf_register_hook(struct nf_hook_ops *reg)
{
struct list_head *i;
spin_lock_bh(&nf_hook_lock);
list_for_each(i, &nf_hooks[reg->pf][reg->hooknum]) {
if (reg->priority < ((struct nf_hook_ops *)i)->priority)
break;
}
list_add_rcu(&reg->list, i->prev);
spin_unlock_bh(&nf_hook_lock);
synchronize_net();
return 0;
}
EXPORT_SYMBOL(nf_register_hook);
void nf_unregister_hook(struct nf_hook_ops *reg)
{
spin_lock_bh(&nf_hook_lock);
list_del_rcu(&reg->list);
spin_unlock_bh(&nf_hook_lock);
synchronize_net();
}
EXPORT_SYMBOL(nf_unregister_hook);
unsigned int nf_iterate(struct list_head *head,
struct sk_buff **skb,
int hook,
const struct net_device *indev,
const struct net_device *outdev,
struct list_head **i,
int (*okfn)(struct sk_buff *),
int hook_thresh)
{
unsigned int verdict;
/*
* The caller must not block between calls to this
* function because of risk of continuing from deleted element.
*/
list_for_each_continue_rcu(*i, head) {
struct nf_hook_ops *elem = (struct nf_hook_ops *)*i;
if (hook_thresh > elem->priority)
continue;
/* Optimization: we don't need to hold module
reference here, since function can't sleep. --RR */
verdict = elem->hook(hook, skb, indev, outdev, okfn);
if (verdict != NF_ACCEPT) {
#ifdef CONFIG_NETFILTER_DEBUG
if (unlikely((verdict & NF_VERDICT_MASK)
> NF_MAX_VERDICT)) {
NFDEBUG("Evil return from %p(%u).\n",
elem->hook, hook);
continue;
}
#endif
if (verdict != NF_REPEAT)
return verdict;
*i = (*i)->prev;
}
}
return NF_ACCEPT;
}
/* Returns 1 if okfn() needs to be executed by the caller,
* -EPERM for NF_DROP, 0 otherwise. */
int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct sk_buff *),
int hook_thresh)
{
struct list_head *elem;
unsigned int verdict;
int ret = 0;
/* We may already have this, but read-locks nest anyway */
rcu_read_lock();
elem = &nf_hooks[pf][hook];
next_hook:
verdict = nf_iterate(&nf_hooks[pf][hook], pskb, hook, indev,
outdev, &elem, okfn, hook_thresh);
if (verdict == NF_ACCEPT || verdict == NF_STOP) {
ret = 1;
goto unlock;
} else if (verdict == NF_DROP) {
kfree_skb(*pskb);
ret = -EPERM;
} else if ((verdict & NF_VERDICT_MASK) == NF_QUEUE) {
NFDEBUG("nf_hook: Verdict = QUEUE.\n");
if (!nf_queue(pskb, elem, pf, hook, indev, outdev, okfn,
verdict >> NF_VERDICT_BITS))
goto next_hook;
}
unlock:
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL(nf_hook_slow);
int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len)
{
struct sk_buff *nskb;
if (writable_len > (*pskb)->len)
return 0;
/* Not exclusive use of packet? Must copy. */
if (skb_shared(*pskb) || skb_cloned(*pskb))
goto copy_skb;
return pskb_may_pull(*pskb, writable_len);
copy_skb:
nskb = skb_copy(*pskb, GFP_ATOMIC);
if (!nskb)
return 0;
BUG_ON(skb_is_nonlinear(nskb));
/* Rest of kernel will get very unhappy if we pass it a
suddenly-orphaned skbuff */
if ((*pskb)->sk)
skb_set_owner_w(nskb, (*pskb)->sk);
kfree_skb(*pskb);
*pskb = nskb;
return 1;
}
EXPORT_SYMBOL(skb_make_writable);
/* This does not belong here, but locally generated errors need it if connection
tracking in use: without this, connection may not be in hash table, and hence
manufactured ICMP or RST packets will not be associated with it. */
void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
EXPORT_SYMBOL(ip_ct_attach);
void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb)
{
void (*attach)(struct sk_buff *, struct sk_buff *);
if (skb->nfct && (attach = ip_ct_attach) != NULL) {
mb(); /* Just to be sure: must be read before executing this */
attach(new, skb);
}
}
EXPORT_SYMBOL(nf_ct_attach);
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *proc_net_netfilter;
EXPORT_SYMBOL(proc_net_netfilter);
#endif
void __init netfilter_init(void)
{
int i, h;
for (i = 0; i < NPROTO; i++) {
for (h = 0; h < NF_MAX_HOOKS; h++)
INIT_LIST_HEAD(&nf_hooks[i][h]);
}
#ifdef CONFIG_PROC_FS
proc_net_netfilter = proc_mkdir("netfilter", proc_net);
if (!proc_net_netfilter)
panic("cannot create netfilter proc entry");
#endif
if (netfilter_queue_init() < 0)
panic("cannot initialize nf_queue");
if (netfilter_log_init() < 0)
panic("cannot initialize nf_log");
}

39
net/netfilter/nf_internals.h Normal file
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#ifndef _NF_INTERNALS_H
#define _NF_INTERNALS_H
#include <linux/config.h>
#include <linux/list.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#ifdef CONFIG_NETFILTER_DEBUG
#define NFDEBUG(format, args...) printk(format , ## args)
#else
#define NFDEBUG(format, args...)
#endif
/* core.c */
extern unsigned int nf_iterate(struct list_head *head,
struct sk_buff **skb,
int hook,
const struct net_device *indev,
const struct net_device *outdev,
struct list_head **i,
int (*okfn)(struct sk_buff *),
int hook_thresh);
/* nf_queue.c */
extern int nf_queue(struct sk_buff **skb,
struct list_head *elem,
int pf, unsigned int hook,
struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct sk_buff *),
unsigned int queuenum);
extern int __init netfilter_queue_init(void);
/* nf_log.c */
extern int __init netfilter_log_init(void);
#endif

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net/netfilter/nf_log.c Normal file
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#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <net/protocol.h>
#include "nf_internals.h"
/* Internal logging interface, which relies on the real
LOG target modules */
#define NF_LOG_PREFIXLEN 128
static struct nf_logger *nf_logging[NPROTO]; /* = NULL */
static DEFINE_SPINLOCK(nf_log_lock);
int nf_log_register(int pf, struct nf_logger *logger)
{
int ret = -EBUSY;
/* Any setup of logging members must be done before
* substituting pointer. */
spin_lock(&nf_log_lock);
if (!nf_logging[pf]) {
rcu_assign_pointer(nf_logging[pf], logger);
ret = 0;
}
spin_unlock(&nf_log_lock);
return ret;
}
EXPORT_SYMBOL(nf_log_register);
void nf_log_unregister_pf(int pf)
{
spin_lock(&nf_log_lock);
nf_logging[pf] = NULL;
spin_unlock(&nf_log_lock);
/* Give time to concurrent readers. */
synchronize_net();
}
EXPORT_SYMBOL(nf_log_unregister_pf);
void nf_log_unregister_logger(struct nf_logger *logger)
{
int i;
spin_lock(&nf_log_lock);
for (i = 0; i < NPROTO; i++) {
if (nf_logging[i] == logger)
nf_logging[i] = NULL;
}
spin_unlock(&nf_log_lock);
synchronize_net();
}
EXPORT_SYMBOL(nf_log_unregister_logger);
void nf_log_packet(int pf,
unsigned int hooknum,
const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
struct nf_loginfo *loginfo,
const char *fmt, ...)
{
va_list args;
char prefix[NF_LOG_PREFIXLEN];
struct nf_logger *logger;
rcu_read_lock();
logger = rcu_dereference(nf_logging[pf]);
if (logger) {
va_start(args, fmt);
vsnprintf(prefix, sizeof(prefix), fmt, args);
va_end(args);
/* We must read logging before nf_logfn[pf] */
logger->logfn(pf, hooknum, skb, in, out, loginfo, prefix);
} else if (net_ratelimit()) {
printk(KERN_WARNING "nf_log_packet: can\'t log since "
"no backend logging module loaded in! Please either "
"load one, or disable logging explicitly\n");
}
rcu_read_unlock();
}
EXPORT_SYMBOL(nf_log_packet);
#ifdef CONFIG_PROC_FS
static void *seq_start(struct seq_file *seq, loff_t *pos)
{
rcu_read_lock();
if (*pos >= NPROTO)
return NULL;
return pos;
}
static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
{
(*pos)++;
if (*pos >= NPROTO)
return NULL;
return pos;
}
static void seq_stop(struct seq_file *s, void *v)
{
rcu_read_unlock();
}
static int seq_show(struct seq_file *s, void *v)
{
loff_t *pos = v;
const struct nf_logger *logger;
logger = rcu_dereference(nf_logging[*pos]);
if (!logger)
return seq_printf(s, "%2lld NONE\n", *pos);
return seq_printf(s, "%2lld %s\n", *pos, logger->name);
}
static struct seq_operations nflog_seq_ops = {
.start = seq_start,
.next = seq_next,
.stop = seq_stop,
.show = seq_show,
};
static int nflog_open(struct inode *inode, struct file *file)
{
return seq_open(file, &nflog_seq_ops);
}
static struct file_operations nflog_file_ops = {
.owner = THIS_MODULE,
.open = nflog_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#endif /* PROC_FS */
int __init netfilter_log_init(void)
{
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *pde;
pde = create_proc_entry("nf_log", S_IRUGO, proc_net_netfilter);
#endif
if (!pde)
return -1;
pde->proc_fops = &nflog_file_ops;
return 0;
}

273
net/netfilter/nf_queue.c Normal file
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#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <net/protocol.h>
#include "nf_internals.h"
/*
* A queue handler may be registered for each protocol. Each is protected by
* long term mutex. The handler must provide an an outfn() to accept packets
* for queueing and must reinject all packets it receives, no matter what.
*/
static struct nf_queue_handler_t {
nf_queue_outfn_t outfn;
void *data;
} queue_handler[NPROTO];
static struct nf_queue_rerouter *queue_rerouter;
static DEFINE_RWLOCK(queue_handler_lock);
int nf_register_queue_handler(int pf, nf_queue_outfn_t outfn, void *data)
{
int ret;
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
if (queue_handler[pf].outfn)
ret = -EBUSY;
else {
queue_handler[pf].outfn = outfn;
queue_handler[pf].data = data;
ret = 0;
}
write_unlock_bh(&queue_handler_lock);
return ret;
}
EXPORT_SYMBOL(nf_register_queue_handler);
/* The caller must flush their queue before this */
int nf_unregister_queue_handler(int pf)
{
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
queue_handler[pf].outfn = NULL;
queue_handler[pf].data = NULL;
write_unlock_bh(&queue_handler_lock);
return 0;
}
EXPORT_SYMBOL(nf_unregister_queue_handler);
int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer)
{
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
memcpy(&queue_rerouter[pf], rer, sizeof(queue_rerouter[pf]));
write_unlock_bh(&queue_handler_lock);
return 0;
}
EXPORT_SYMBOL_GPL(nf_register_queue_rerouter);
int nf_unregister_queue_rerouter(int pf)
{
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
memset(&queue_rerouter[pf], 0, sizeof(queue_rerouter[pf]));
write_unlock_bh(&queue_handler_lock);
return 0;
}
EXPORT_SYMBOL_GPL(nf_unregister_queue_rerouter);
void nf_unregister_queue_handlers(nf_queue_outfn_t outfn)
{
int pf;
write_lock_bh(&queue_handler_lock);
for (pf = 0; pf < NPROTO; pf++) {
if (queue_handler[pf].outfn == outfn) {
queue_handler[pf].outfn = NULL;
queue_handler[pf].data = NULL;
}
}
write_unlock_bh(&queue_handler_lock);
}
EXPORT_SYMBOL_GPL(nf_unregister_queue_handlers);
/*
* Any packet that leaves via this function must come back
* through nf_reinject().
*/
int nf_queue(struct sk_buff **skb,
struct list_head *elem,
int pf, unsigned int hook,
struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct sk_buff *),
unsigned int queuenum)
{
int status;
struct nf_info *info;
#ifdef CONFIG_BRIDGE_NETFILTER
struct net_device *physindev = NULL;
struct net_device *physoutdev = NULL;
#endif
/* QUEUE == DROP if noone is waiting, to be safe. */
read_lock(&queue_handler_lock);
if (!queue_handler[pf].outfn) {
read_unlock(&queue_handler_lock);
kfree_skb(*skb);
return 1;
}
info = kmalloc(sizeof(*info)+queue_rerouter[pf].rer_size, GFP_ATOMIC);
if (!info) {
if (net_ratelimit())
printk(KERN_ERR "OOM queueing packet %p\n",
*skb);
read_unlock(&queue_handler_lock);
kfree_skb(*skb);
return 1;
}
*info = (struct nf_info) {
(struct nf_hook_ops *)elem, pf, hook, indev, outdev, okfn };
/* If it's going away, ignore hook. */
if (!try_module_get(info->elem->owner)) {
read_unlock(&queue_handler_lock);
kfree(info);
return 0;
}
/* Bump dev refs so they don't vanish while packet is out */
if (indev) dev_hold(indev);
if (outdev) dev_hold(outdev);
#ifdef CONFIG_BRIDGE_NETFILTER
if ((*skb)->nf_bridge) {
physindev = (*skb)->nf_bridge->physindev;
if (physindev) dev_hold(physindev);
physoutdev = (*skb)->nf_bridge->physoutdev;
if (physoutdev) dev_hold(physoutdev);
}
#endif
if (queue_rerouter[pf].save)
queue_rerouter[pf].save(*skb, info);
status = queue_handler[pf].outfn(*skb, info, queuenum,
queue_handler[pf].data);
if (status >= 0 && queue_rerouter[pf].reroute)
status = queue_rerouter[pf].reroute(skb, info);
read_unlock(&queue_handler_lock);
if (status < 0) {
/* James M doesn't say fuck enough. */
if (indev) dev_put(indev);
if (outdev) dev_put(outdev);
#ifdef CONFIG_BRIDGE_NETFILTER
if (physindev) dev_put(physindev);
if (physoutdev) dev_put(physoutdev);
#endif
module_put(info->elem->owner);
kfree(info);
kfree_skb(*skb);
return 1;
}
return 1;
}
void nf_reinject(struct sk_buff *skb, struct nf_info *info,
unsigned int verdict)
{
struct list_head *elem = &info->elem->list;
struct list_head *i;
rcu_read_lock();
/* Release those devices we held, or Alexey will kill me. */
if (info->indev) dev_put(info->indev);
if (info->outdev) dev_put(info->outdev);
#ifdef CONFIG_BRIDGE_NETFILTER
if (skb->nf_bridge) {
if (skb->nf_bridge->physindev)
dev_put(skb->nf_bridge->physindev);
if (skb->nf_bridge->physoutdev)
dev_put(skb->nf_bridge->physoutdev);
}
#endif
/* Drop reference to owner of hook which queued us. */
module_put(info->elem->owner);
list_for_each_rcu(i, &nf_hooks[info->pf][info->hook]) {
if (i == elem)
break;
}
if (elem == &nf_hooks[info->pf][info->hook]) {
/* The module which sent it to userspace is gone. */
NFDEBUG("%s: module disappeared, dropping packet.\n",
__FUNCTION__);
verdict = NF_DROP;
}
/* Continue traversal iff userspace said ok... */
if (verdict == NF_REPEAT) {
elem = elem->prev;
verdict = NF_ACCEPT;
}
if (verdict == NF_ACCEPT) {
next_hook:
verdict = nf_iterate(&nf_hooks[info->pf][info->hook],
&skb, info->hook,
info->indev, info->outdev, &elem,
info->okfn, INT_MIN);
}
switch (verdict & NF_VERDICT_MASK) {
case NF_ACCEPT:
info->okfn(skb);
break;
case NF_QUEUE:
if (!nf_queue(&skb, elem, info->pf, info->hook,
info->indev, info->outdev, info->okfn,
verdict >> NF_VERDICT_BITS))
goto next_hook;
break;
}
rcu_read_unlock();
if (verdict == NF_DROP)
kfree_skb(skb);
kfree(info);
return;
}
EXPORT_SYMBOL(nf_reinject);
int __init netfilter_queue_init(void)
{
queue_rerouter = kmalloc(NPROTO * sizeof(struct nf_queue_rerouter),
GFP_KERNEL);
if (!queue_rerouter)
return -ENOMEM;
memset(queue_rerouter, 0, NPROTO * sizeof(struct nf_queue_rerouter));
return 0;
}

132
net/netfilter/nf_sockopt.c Normal file
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#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <net/sock.h>
#include "nf_internals.h"
/* Sockopts only registered and called from user context, so
net locking would be overkill. Also, [gs]etsockopt calls may
sleep. */
static DECLARE_MUTEX(nf_sockopt_mutex);
static LIST_HEAD(nf_sockopts);
/* Do exclusive ranges overlap? */
static inline int overlap(int min1, int max1, int min2, int max2)
{
return max1 > min2 && min1 < max2;
}
/* Functions to register sockopt ranges (exclusive). */
int nf_register_sockopt(struct nf_sockopt_ops *reg)
{
struct list_head *i;
int ret = 0;
if (down_interruptible(&nf_sockopt_mutex) != 0)
return -EINTR;
list_for_each(i, &nf_sockopts) {
struct nf_sockopt_ops *ops = (struct nf_sockopt_ops *)i;
if (ops->pf == reg->pf
&& (overlap(ops->set_optmin, ops->set_optmax,
reg->set_optmin, reg->set_optmax)
|| overlap(ops->get_optmin, ops->get_optmax,
reg->get_optmin, reg->get_optmax))) {
NFDEBUG("nf_sock overlap: %u-%u/%u-%u v %u-%u/%u-%u\n",
ops->set_optmin, ops->set_optmax,
ops->get_optmin, ops->get_optmax,
reg->set_optmin, reg->set_optmax,
reg->get_optmin, reg->get_optmax);
ret = -EBUSY;
goto out;
}
}
list_add(&reg->list, &nf_sockopts);
out:
up(&nf_sockopt_mutex);
return ret;
}
EXPORT_SYMBOL(nf_register_sockopt);
void nf_unregister_sockopt(struct nf_sockopt_ops *reg)
{
/* No point being interruptible: we're probably in cleanup_module() */
restart:
down(&nf_sockopt_mutex);
if (reg->use != 0) {
/* To be woken by nf_sockopt call... */
/* FIXME: Stuart Young's name appears gratuitously. */
set_current_state(TASK_UNINTERRUPTIBLE);
reg->cleanup_task = current;
up(&nf_sockopt_mutex);
schedule();
goto restart;
}
list_del(&reg->list);
up(&nf_sockopt_mutex);
}
EXPORT_SYMBOL(nf_unregister_sockopt);
/* Call get/setsockopt() */
static int nf_sockopt(struct sock *sk, int pf, int val,
char __user *opt, int *len, int get)
{
struct list_head *i;
struct nf_sockopt_ops *ops;
int ret;
if (down_interruptible(&nf_sockopt_mutex) != 0)
return -EINTR;
list_for_each(i, &nf_sockopts) {
ops = (struct nf_sockopt_ops *)i;
if (ops->pf == pf) {
if (get) {
if (val >= ops->get_optmin
&& val < ops->get_optmax) {
ops->use++;
up(&nf_sockopt_mutex);
ret = ops->get(sk, val, opt, len);
goto out;
}
} else {
if (val >= ops->set_optmin
&& val < ops->set_optmax) {
ops->use++;
up(&nf_sockopt_mutex);
ret = ops->set(sk, val, opt, *len);
goto out;
}
}
}
}
up(&nf_sockopt_mutex);
return -ENOPROTOOPT;
out:
down(&nf_sockopt_mutex);
ops->use--;
if (ops->cleanup_task)
wake_up_process(ops->cleanup_task);
up(&nf_sockopt_mutex);
return ret;
}
int nf_setsockopt(struct sock *sk, int pf, int val, char __user *opt,
int len)
{
return nf_sockopt(sk, pf, val, opt, &len, 0);
}
EXPORT_SYMBOL(nf_setsockopt);
int nf_getsockopt(struct sock *sk, int pf, int val, char __user *opt, int *len)
{
return nf_sockopt(sk, pf, val, opt, len, 1);
}
EXPORT_SYMBOL(nf_getsockopt);