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[NETFILTER]: Core changes required by upcoming nfnetlink_queue code

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- split netfiler verdict in 16bit verdict and 16bit queue number
- add 'queuenum' argument to nf_queue_outfn_t and its users ip[6]_queue
- move NFNL_SUBSYS_ definitions from enum to #define
- introduce autoloading for nfnetlink subsystem modules
- add MODULE_ALIAS_NFNL_SUBSYS macro
- add nf_unregister_queue_handlers() to register all handlers for a given
  nf_queue_outfn_t
- add more verbose DEBUGP macro definition to nfnetlink.c
- make nfnetlink_subsys_register fail if subsys already exists
- add some more comments and debug statements to nfnetlink.c

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 19:43:44 -07:00 committed by David S. Miller
parent 2cc7d57309
commit 0ab43f8499
6 changed files with 83 additions and 25 deletions
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14
include/linux/netfilter.h
View file

@ -21,6 +21,16 @@
#define NF_STOP 5
#define NF_MAX_VERDICT NF_STOP
/* we overload the higher bits for encoding auxiliary data such as the queue
* number. Not nice, but better than additional function arguments. */
#define NF_VERDICT_MASK 0x0000ffff
#define NF_VERDICT_BITS 16
#define NF_VERDICT_QMASK 0xffff0000
#define NF_VERDICT_QBITS 16
#define NF_QUEUE_NR(x) ((x << NF_VERDICT_QBITS) & NF_VERDICT_QMASK || NF_QUEUE)
/* only for userspace compatibility */
#ifndef __KERNEL__
/* Generic cache responses from hook functions.
@ -179,10 +189,12 @@ int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt,
/* Packet queuing */
typedef int (*nf_queue_outfn_t)(struct sk_buff *skb,
struct nf_info *info, void *data);
struct nf_info *info,
unsigned int queuenum, void *data);
extern int nf_register_queue_handler(int pf,
nf_queue_outfn_t outfn, void *data);
extern int nf_unregister_queue_handler(int pf);
extern void nf_unregister_queue_handlers(nf_queue_outfn_t outfn);
extern void nf_reinject(struct sk_buff *skb,
struct nf_info *info,
unsigned int verdict);

20
include/linux/netfilter/nfnetlink.h
View file

@ -69,15 +69,14 @@ struct nfgenmsg {
#define NFNL_SUBSYS_ID(x) ((x & 0xff00) >> 8)
#define NFNL_MSG_TYPE(x) (x & 0x00ff)
enum nfnl_subsys_id {
NFNL_SUBSYS_NONE = 0,
NFNL_SUBSYS_CTNETLINK,
NFNL_SUBSYS_CTNETLINK_EXP,
NFNL_SUBSYS_IPTNETLINK,
NFNL_SUBSYS_QUEUE,
NFNL_SUBSYS_ULOG,
NFNL_SUBSYS_COUNT,
};
/* No enum here, otherwise __stringify() trick of MODULE_ALIAS_NFNL_SUBSYS()
* won't work anymore */
#define NFNL_SUBSYS_NONE 0
#define NFNL_SUBSYS_CTNETLINK 1
#define NFNL_SUBSYS_CTNETLINK_EXP 2
#define NFNL_SUBSYS_QUEUE 3
#define NFNL_SUBSYS_ULOG 4
#define NFNL_SUBSYS_COUNT 5
#ifdef __KERNEL__
@ -142,5 +141,8 @@ extern int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group,
int echo);
extern int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags);
#define MODULE_ALIAS_NFNL_SUBSYS(subsys) \
MODULE_ALIAS("nfnetlink-subsys-" __stringify(subsys))
#endif /* __KERNEL__ */
#endif /* _NFNETLINK_H */

40
net/core/netfilter.c
View file

@ -221,7 +221,8 @@ static unsigned int nf_iterate(struct list_head *head,
verdict = elem->hook(hook, skb, indev, outdev, okfn);
if (verdict != NF_ACCEPT) {
#ifdef CONFIG_NETFILTER_DEBUG
if (unlikely(verdict > NF_MAX_VERDICT)) {
if (unlikely((verdict & NF_VERDICT_MASK)
> NF_MAX_VERDICT)) {
NFDEBUG("Evil return from %p(%u).\n",
elem->hook, hook);
continue;
@ -239,6 +240,9 @@ 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;
@ -255,6 +259,9 @@ int nf_register_queue_handler(int pf, nf_queue_outfn_t outfn, void *data)
/* 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;
@ -286,6 +293,20 @@ int nf_unregister_queue_rerouter(int pf)
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().
@ -295,7 +316,8 @@ static int nf_queue(struct sk_buff **skb,
int pf, unsigned int hook,
struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct sk_buff *))
int (*okfn)(struct sk_buff *),
unsigned int queuenum)
{
int status;
struct nf_info *info;
@ -347,7 +369,8 @@ static int nf_queue(struct sk_buff **skb,
if (queue_rerouter[pf].save)
queue_rerouter[pf].save(*skb, info);
status = queue_handler[pf].outfn(*skb, info, queue_handler[pf].data);
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);
@ -397,9 +420,10 @@ int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
} else if (verdict == NF_DROP) {
kfree_skb(*pskb);
ret = -EPERM;
} else if (verdict == NF_QUEUE) {
} else if ((verdict & NF_VERDICT_MASK) == NF_QUEUE) {
NFDEBUG("nf_hook: Verdict = QUEUE.\n");
if (!nf_queue(pskb, elem, pf, hook, indev, outdev, okfn))
if (!nf_queue(pskb, elem, pf, hook, indev, outdev, okfn,
verdict >> NF_VERDICT_BITS))
goto next_hook;
}
unlock:
@ -456,14 +480,15 @@ void nf_reinject(struct sk_buff *skb, struct nf_info *info,
info->okfn, INT_MIN);
}
switch (verdict) {
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))
info->indev, info->outdev, info->okfn,
verdict >> NF_VERDICT_BITS))
goto next_hook;
break;
}
@ -613,6 +638,7 @@ 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);

3
net/ipv4/netfilter/ip_queue.c
View file

@ -280,7 +280,8 @@ ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
}
static int
ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, void *data)
ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info,
unsigned int queuenum, void *data)
{
int status = -EINVAL;
struct sk_buff *nskb;

3
net/ipv6/netfilter/ip6_queue.c
View file

@ -278,7 +278,8 @@ ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
}
static int
ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, void *data)
ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info,
unsigned int queuenum, void *data)
{
int status = -EINVAL;
struct sk_buff *nskb;

28
net/netfilter/nfnetlink.c
View file

@ -44,7 +44,9 @@ MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
static char __initdata nfversion[] = "0.30";
#if 0
#define DEBUGP printk
#define DEBUGP(format, args...) \
printk(KERN_DEBUG "%s(%d):%s(): " format, __FILE__, \
__LINE__, __FUNCTION__, ## args)
#else
#define DEBUGP(format, args...)
#endif
@ -67,11 +69,11 @@ int nfnetlink_subsys_register(struct nfnetlink_subsystem *n)
{
DEBUGP("registering subsystem ID %u\n", n->subsys_id);
/* If the netlink socket wasn't created, then fail */
if (!nfnl)
return -1;
nfnl_lock();
if (subsys_table[n->subsys_id]) {
nfnl_unlock();
return -EBUSY;
}
subsys_table[n->subsys_id] = n;
nfnl_unlock();
@ -227,8 +229,18 @@ static inline int nfnetlink_rcv_msg(struct sk_buff *skb,
type = nlh->nlmsg_type;
ss = nfnetlink_get_subsys(type);
if (!ss)
if (!ss) {
#ifdef CONFIG_KMOD
/* don't call nfnl_shunlock, since it would reenter
* with further packet processing */
up(&nfnl_sem);
request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
nfnl_shlock();
ss = nfnetlink_get_subsys(type);
if (!ss)
#endif
goto err_inval;
}
nc = nfnetlink_find_client(type, ss);
if (!nc) {
@ -252,12 +264,14 @@ static inline int nfnetlink_rcv_msg(struct sk_buff *skb,
if (err < 0)
goto err_inval;
DEBUGP("calling handler\n");
err = nc->call(nfnl, skb, nlh, cda, errp);
*errp = err;
return err;
}
err_inval:
DEBUGP("returning -EINVAL\n");
*errp = -EINVAL;
return -1;
}
@ -311,6 +325,8 @@ static void nfnetlink_rcv(struct sock *sk, int len)
kfree_skb(skb);
}
/* don't call nfnl_shunlock, since it would reenter
* with further packet processing */
up(&nfnl_sem);
} while(nfnl && nfnl->sk_receive_queue.qlen);
}