root/net/ipv4/tunnel4.c

DEFINITIONS

1. fam_handlers
2. xfrm4_tunnel_register
3. xfrm4_tunnel_deregister
4. tunnel4_rcv
5. tunnel64_rcv
6. tunnel4_err
7. tunnel64_err
8. tunnel4_init
9. tunnel4_fini

/* tunnel4.c: Generic IP tunnel transformer.
 *
 * Copyright (C) 2003 David S. Miller (davem@redhat.com)
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/icmp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/xfrm.h>

static struct xfrm_tunnel *tunnel4_handlers;
static struct xfrm_tunnel *tunnel64_handlers;
static DEFINE_MUTEX(tunnel4_mutex);

static inline struct xfrm_tunnel **fam_handlers(unsigned short family)
{
        return (family == AF_INET) ? &tunnel4_handlers : &tunnel64_handlers;
}

int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family)
{
        struct xfrm_tunnel **pprev;
        int ret = -EEXIST;
        int priority = handler->priority;

        mutex_lock(&tunnel4_mutex);

        for (pprev = fam_handlers(family); *pprev; pprev = &(*pprev)->next) {
                if ((*pprev)->priority > priority)
                        break;
                if ((*pprev)->priority == priority)
                        goto err;
        }

        handler->next = *pprev;
        *pprev = handler;

        ret = 0;

err:
        mutex_unlock(&tunnel4_mutex);

        return ret;
}

EXPORT_SYMBOL(xfrm4_tunnel_register);

int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family)
{
        struct xfrm_tunnel **pprev;
        int ret = -ENOENT;

        mutex_lock(&tunnel4_mutex);

        for (pprev = fam_handlers(family); *pprev; pprev = &(*pprev)->next) {
                if (*pprev == handler) {
                        *pprev = handler->next;
                        ret = 0;
                        break;
                }
        }

        mutex_unlock(&tunnel4_mutex);

        synchronize_net();

        return ret;
}

EXPORT_SYMBOL(xfrm4_tunnel_deregister);

static int tunnel4_rcv(struct sk_buff *skb)
{
        struct xfrm_tunnel *handler;

        if (!pskb_may_pull(skb, sizeof(struct iphdr)))
                goto drop;

        for (handler = tunnel4_handlers; handler; handler = handler->next)
                if (!handler->handler(skb))
                        return 0;

        icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);

drop:
        kfree_skb(skb);
        return 0;
}

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
static int tunnel64_rcv(struct sk_buff *skb)
{
        struct xfrm_tunnel *handler;

        if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
                goto drop;

        for (handler = tunnel64_handlers; handler; handler = handler->next)
                if (!handler->handler(skb))
                        return 0;

        icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);

drop:
        kfree_skb(skb);
        return 0;
}
#endif

static void tunnel4_err(struct sk_buff *skb, u32 info)
{
        struct xfrm_tunnel *handler;

        for (handler = tunnel4_handlers; handler; handler = handler->next)
                if (!handler->err_handler(skb, info))
                        break;
}

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
static void tunnel64_err(struct sk_buff *skb, u32 info)
{
        struct xfrm_tunnel *handler;

        for (handler = tunnel64_handlers; handler; handler = handler->next)
                if (!handler->err_handler(skb, info))
                        break;
}
#endif

static struct net_protocol tunnel4_protocol = {
        .handler        =       tunnel4_rcv,
        .err_handler    =       tunnel4_err,
        .no_policy      =       1,
        .netns_ok       =       1,
};

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
static struct net_protocol tunnel64_protocol = {
        .handler        =       tunnel64_rcv,
        .err_handler    =       tunnel64_err,
        .no_policy      =       1,
        .netns_ok       =       1,
};
#endif

static int __init tunnel4_init(void)
{
        if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP)) {
                printk(KERN_ERR "tunnel4 init: can't add protocol\n");
                return -EAGAIN;
        }
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
        if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6)) {
                printk(KERN_ERR "tunnel64 init: can't add protocol\n");
                inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
                return -EAGAIN;
        }
#endif
        return 0;
}

static void __exit tunnel4_fini(void)
{
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
        if (inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6))
                printk(KERN_ERR "tunnel64 close: can't remove protocol\n");
#endif
        if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
                printk(KERN_ERR "tunnel4 close: can't remove protocol\n");
}

module_init(tunnel4_init);
module_exit(tunnel4_fini);
MODULE_LICENSE("GPL");