Handle GSO packets in nf_queue by segmenting them before queueing to avoid breaking GSO in case they get mangled. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
288 lines
7.2 KiB
C
288 lines
7.2 KiB
C
/* 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/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"
|
|
|
|
static DEFINE_SPINLOCK(afinfo_lock);
|
|
|
|
struct nf_afinfo *nf_afinfo[NPROTO];
|
|
EXPORT_SYMBOL(nf_afinfo);
|
|
|
|
int nf_register_afinfo(struct nf_afinfo *afinfo)
|
|
{
|
|
spin_lock(&afinfo_lock);
|
|
rcu_assign_pointer(nf_afinfo[afinfo->family], afinfo);
|
|
spin_unlock(&afinfo_lock);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_register_afinfo);
|
|
|
|
void nf_unregister_afinfo(struct nf_afinfo *afinfo)
|
|
{
|
|
spin_lock(&afinfo_lock);
|
|
rcu_assign_pointer(nf_afinfo[afinfo->family], NULL);
|
|
spin_unlock(&afinfo_lock);
|
|
synchronize_rcu();
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_unregister_afinfo);
|
|
|
|
/* 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(®->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(®->list);
|
|
spin_unlock_bh(&nf_hook_lock);
|
|
|
|
synchronize_net();
|
|
}
|
|
EXPORT_SYMBOL(nf_unregister_hook);
|
|
|
|
int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n)
|
|
{
|
|
unsigned int i;
|
|
int err = 0;
|
|
|
|
for (i = 0; i < n; i++) {
|
|
err = nf_register_hook(®[i]);
|
|
if (err)
|
|
goto err;
|
|
}
|
|
return err;
|
|
|
|
err:
|
|
if (i > 0)
|
|
nf_unregister_hooks(reg, i);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL(nf_register_hooks);
|
|
|
|
void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < n; i++)
|
|
nf_unregister_hook(®[i]);
|
|
}
|
|
EXPORT_SYMBOL(nf_unregister_hooks);
|
|
|
|
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);
|
|
|
|
u_int16_t nf_csum_update(u_int32_t oldval, u_int32_t newval, u_int32_t csum)
|
|
{
|
|
u_int32_t diff[] = { oldval, newval };
|
|
|
|
return csum_fold(csum_partial((char *)diff, sizeof(diff), ~csum));
|
|
}
|
|
EXPORT_SYMBOL(nf_csum_update);
|
|
|
|
u_int16_t nf_proto_csum_update(struct sk_buff *skb,
|
|
u_int32_t oldval, u_int32_t newval,
|
|
u_int16_t csum, int pseudohdr)
|
|
{
|
|
if (skb->ip_summed != CHECKSUM_PARTIAL) {
|
|
csum = nf_csum_update(oldval, newval, csum);
|
|
if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
|
|
skb->csum = nf_csum_update(oldval, newval, skb->csum);
|
|
} else if (pseudohdr)
|
|
csum = ~nf_csum_update(oldval, newval, ~csum);
|
|
|
|
return csum;
|
|
}
|
|
EXPORT_SYMBOL(nf_proto_csum_update);
|
|
|
|
/* 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");
|
|
}
|