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#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/in.h>
#include <linux/netdevice.h>
#include <linux/version.h>
#include <linux/spinlock.h>
#include <net/protocol.h>
#include "gre.h"
struct gre_protocol *gre_proto[GREPROTO_MAX] ____cacheline_aligned_in_smp;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
static rwlock_t gre_proto_lock=RW_LOCK_UNLOCKED;
#else
static DEFINE_SPINLOCK(gre_proto_lock);
#endif
int gre_add_protocol(struct gre_protocol *proto, u8 version)
{
int ret;
if (version >= GREPROTO_MAX)
return -EINVAL;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
write_lock_bh(&gre_proto_lock);
#else
spin_lock(&gre_proto_lock);
#endif
if (gre_proto[version]) {
ret = -EAGAIN;
} else {
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
gre_proto[version] = proto;
#else
rcu_assign_pointer(gre_proto[version], proto);
#endif
ret = 0;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
write_unlock_bh(&gre_proto_lock);
#else
spin_unlock(&gre_proto_lock);
#endif
return ret;
}
int gre_del_protocol(struct gre_protocol *proto, u8 version)
{
if (version >= GREPROTO_MAX)
goto out_err;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
write_lock_bh(&gre_proto_lock);
#else
spin_lock(&gre_proto_lock);
#endif
if (gre_proto[version] == proto)
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
gre_proto[version] = NULL;
#else
rcu_assign_pointer(gre_proto[version], NULL);
#endif
else
goto out_err_unlock;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
write_unlock_bh(&gre_proto_lock);
#else
spin_unlock(&gre_proto_lock);
synchronize_rcu();
#endif
return 0;
out_err_unlock:
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
write_unlock_bh(&gre_proto_lock);
#else
spin_unlock(&gre_proto_lock);
#endif
out_err:
return -EINVAL;
}
static int gre_rcv(struct sk_buff *skb)
{
u8 ver;
int ret;
struct gre_protocol *proto;
if (!pskb_may_pull(skb, 12))
goto drop_nolock;
ver = skb->data[1]&0x7f;
if (ver >= GREPROTO_MAX)
goto drop_nolock;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
read_lock(&gre_proto_lock);
proto = gre_proto[ver];
#else
rcu_read_lock();
proto = rcu_dereference(gre_proto[ver]);
#endif
if (!proto || !proto->handler)
goto drop;
ret = proto->handler(skb);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
read_unlock(&gre_proto_lock);
#else
rcu_read_unlock();
#endif
return ret;
drop:
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
read_unlock(&gre_proto_lock);
#else
rcu_read_unlock();
#endif
drop_nolock:
kfree_skb(skb);
return NET_RX_DROP;
}
static void gre_err(struct sk_buff *skb, u32 info)
{
u8 ver;
struct gre_protocol *proto;
if (!pskb_may_pull(skb, 12))
goto drop_nolock;
ver=skb->data[1]&0x7f;
if (ver>=GREPROTO_MAX)
goto drop_nolock;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
read_lock(&gre_proto_lock);
proto = gre_proto[ver];
#else
rcu_read_lock();
proto = rcu_dereference(gre_proto[ver]);
#endif
if (!proto || !proto->err_handler)
goto drop;
proto->err_handler(skb, info);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
read_unlock(&gre_proto_lock);
#else
rcu_read_unlock();
#endif
return;
drop:
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
read_unlock(&gre_proto_lock);
#else
rcu_read_unlock();
#endif
drop_nolock:
kfree_skb(skb);
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
static struct inet_protocol net_gre_protocol = {
.handler = gre_rcv,
.err_handler = gre_err,
.protocol = IPPROTO_GRE,
.name = "GRE",
};
#else
static struct net_protocol net_gre_protocol = {
.handler = gre_rcv,
.err_handler = gre_err,
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,24)
.netns_ok=1,
#endif
};
#endif
static int __init gre_init(void)
{
printk(KERN_INFO "GRE over IPv4 demultiplexor driver");
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
inet_add_protocol(&net_gre_protocol);
#else
if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
printk(KERN_INFO "gre: can't add protocol\n");
return -EAGAIN;
}
#endif
return 0;
}
static void __exit gre_exit(void)
{
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
inet_del_protocol(&net_gre_protocol);
#else
inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
#endif
}
module_init(gre_init);
module_exit(gre_exit);
MODULE_DESCRIPTION("GRE over IPv4 demultiplexor driver");
MODULE_AUTHOR("Kozlov D. (xeb@mail.ru)");
MODULE_LICENSE("GPL");
EXPORT_SYMBOL_GPL(gre_add_protocol);
EXPORT_SYMBOL_GPL(gre_del_protocol);
|
