xfrm6_tunnel.c

Go to the documentation of this file.

/*
 * Copyright (C)2003,2004 USAGI/WIDE Project
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Authors  Mitsuru KANDA  <[email protected]>
 *      YOSHIFUJI Hideaki <[email protected]>
 *
 * Based on net/ipv4/xfrm4_tunnel.c
 *
 */
#include <linux/module.h>
#include <linux/xfrm.h>
#include <linux/slab.h>
#include <linux/rculist.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/ipv6.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <linux/mutex.h>
#include <net/netns/generic.h>

#define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
#define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256

#define XFRM6_TUNNEL_SPI_MIN    1
#define XFRM6_TUNNEL_SPI_MAX    0xffffffff

struct xfrm6_tunnel_net {
    struct hlist_head spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
    struct hlist_head spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
    u32 spi;
};

static int xfrm6_tunnel_net_id __read_mostly;
static inline struct xfrm6_tunnel_net *xfrm6_tunnel_pernet(struct net *net)
{
    return net_generic(net, xfrm6_tunnel_net_id);
}

/*
 * xfrm_tunnel_spi things are for allocating unique id ("spi")
 * per xfrm_address_t.
 */
struct xfrm6_tunnel_spi {
    struct hlist_node   list_byaddr;
    struct hlist_node   list_byspi;
    xfrm_address_t      addr;
    u32         spi;
    atomic_t        refcnt;
    struct rcu_head     rcu_head;
};

static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);

static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;

static inline unsigned int xfrm6_tunnel_spi_hash_byaddr(const xfrm_address_t *addr)
{
    unsigned int h;

    h = (__force u32)(addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3]);
    h ^= h >> 16;
    h ^= h >> 8;
    h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;

    return h;
}

static inline unsigned int xfrm6_tunnel_spi_hash_byspi(u32 spi)
{
    return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
}

static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
{
    struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
    struct xfrm6_tunnel_spi *x6spi;
    struct hlist_node *pos;

    hlist_for_each_entry_rcu(x6spi, pos,
                 &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
                 list_byaddr) {
        if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0)
            return x6spi;
    }

    return NULL;
}

__be32 xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
{
    struct xfrm6_tunnel_spi *x6spi;
    u32 spi;

    rcu_read_lock_bh();
    x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
    spi = x6spi ? x6spi->spi : 0;
    rcu_read_unlock_bh();
    return htonl(spi);
}

EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);

static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
{
    struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
    struct xfrm6_tunnel_spi *x6spi;
    int index = xfrm6_tunnel_spi_hash_byspi(spi);
    struct hlist_node *pos;

    hlist_for_each_entry(x6spi, pos,
                 &xfrm6_tn->spi_byspi[index],
                 list_byspi) {
        if (x6spi->spi == spi)
            return -1;
    }
    return index;
}

static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
{
    struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
    u32 spi;
    struct xfrm6_tunnel_spi *x6spi;
    int index;

    if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
        xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
        xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
    else
        xfrm6_tn->spi++;

    for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
        index = __xfrm6_tunnel_spi_check(net, spi);
        if (index >= 0)
            goto alloc_spi;
    }
    for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
        index = __xfrm6_tunnel_spi_check(net, spi);
        if (index >= 0)
            goto alloc_spi;
    }
    spi = 0;
    goto out;
alloc_spi:
    xfrm6_tn->spi = spi;
    x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
    if (!x6spi)
        goto out;

    memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
    x6spi->spi = spi;
    atomic_set(&x6spi->refcnt, 1);

    hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);

    index = xfrm6_tunnel_spi_hash_byaddr(saddr);
    hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
out:
    return spi;
}

__be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
{
    struct xfrm6_tunnel_spi *x6spi;
    u32 spi;

    spin_lock_bh(&xfrm6_tunnel_spi_lock);
    x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
    if (x6spi) {
        atomic_inc(&x6spi->refcnt);
        spi = x6spi->spi;
    } else
        spi = __xfrm6_tunnel_alloc_spi(net, saddr);
    spin_unlock_bh(&xfrm6_tunnel_spi_lock);

    return htonl(spi);
}

EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);

static void x6spi_destroy_rcu(struct rcu_head *head)
{
    kmem_cache_free(xfrm6_tunnel_spi_kmem,
            container_of(head, struct xfrm6_tunnel_spi, rcu_head));
}

static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
{
    struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
    struct xfrm6_tunnel_spi *x6spi;
    struct hlist_node *pos, *n;

    spin_lock_bh(&xfrm6_tunnel_spi_lock);

    hlist_for_each_entry_safe(x6spi, pos, n,
                  &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
                  list_byaddr)
    {
        if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
            if (atomic_dec_and_test(&x6spi->refcnt)) {
                hlist_del_rcu(&x6spi->list_byaddr);
                hlist_del_rcu(&x6spi->list_byspi);
                call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
                break;
            }
        }
    }
    spin_unlock_bh(&xfrm6_tunnel_spi_lock);
}

static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
{
    skb_push(skb, -skb_network_offset(skb));
    return 0;
}

static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
{
    return skb_network_header(skb)[IP6CB(skb)->nhoff];
}

static int xfrm6_tunnel_rcv(struct sk_buff *skb)
{
    struct net *net = dev_net(skb->dev);
    const struct ipv6hdr *iph = ipv6_hdr(skb);
    __be32 spi;

    spi = xfrm6_tunnel_spi_lookup(net, (const xfrm_address_t *)&iph->saddr);
    return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi);
}

static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                u8 type, u8 code, int offset, __be32 info)
{
    /* xfrm6_tunnel native err handling */
    switch (type) {
    case ICMPV6_DEST_UNREACH:
        switch (code) {
        case ICMPV6_NOROUTE:
        case ICMPV6_ADM_PROHIBITED:
        case ICMPV6_NOT_NEIGHBOUR:
        case ICMPV6_ADDR_UNREACH:
        case ICMPV6_PORT_UNREACH:
        default:
            break;
        }
        break;
    case ICMPV6_PKT_TOOBIG:
        break;
    case ICMPV6_TIME_EXCEED:
        switch (code) {
        case ICMPV6_EXC_HOPLIMIT:
            break;
        case ICMPV6_EXC_FRAGTIME:
        default:
            break;
        }
        break;
    case ICMPV6_PARAMPROB:
        switch (code) {
        case ICMPV6_HDR_FIELD: break;
        case ICMPV6_UNK_NEXTHDR: break;
        case ICMPV6_UNK_OPTION: break;
        }
        break;
    default:
        break;
    }

    return 0;
}

static int xfrm6_tunnel_init_state(struct xfrm_state *x)
{
    if (x->props.mode != XFRM_MODE_TUNNEL)
        return -EINVAL;

    if (x->encap)
        return -EINVAL;

    x->props.header_len = sizeof(struct ipv6hdr);

    return 0;
}

static void xfrm6_tunnel_destroy(struct xfrm_state *x)
{
    struct net *net = xs_net(x);

    xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
}

static const struct xfrm_type xfrm6_tunnel_type = {
    .description    = "IP6IP6",
    .owner          = THIS_MODULE,
    .proto      = IPPROTO_IPV6,
    .init_state = xfrm6_tunnel_init_state,
    .destructor = xfrm6_tunnel_destroy,
    .input      = xfrm6_tunnel_input,
    .output     = xfrm6_tunnel_output,
};

static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
    .handler    = xfrm6_tunnel_rcv,
    .err_handler    = xfrm6_tunnel_err,
    .priority   = 2,
};

static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
    .handler    = xfrm6_tunnel_rcv,
    .err_handler    = xfrm6_tunnel_err,
    .priority   = 2,
};

static int __net_init xfrm6_tunnel_net_init(struct net *net)
{
    struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
    unsigned int i;

    for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
        INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
    for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
        INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
    xfrm6_tn->spi = 0;

    return 0;
}

static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
{
}

static struct pernet_operations xfrm6_tunnel_net_ops = {
    .init   = xfrm6_tunnel_net_init,
    .exit   = xfrm6_tunnel_net_exit,
    .id = &xfrm6_tunnel_net_id,
    .size   = sizeof(struct xfrm6_tunnel_net),
};

static int __init xfrm6_tunnel_init(void)
{
    int rv;

    xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
                          sizeof(struct xfrm6_tunnel_spi),
                          0, SLAB_HWCACHE_ALIGN,
                          NULL);
    if (!xfrm6_tunnel_spi_kmem)
        return -ENOMEM;
    rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
    if (rv < 0)
        goto out_pernet;
    rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
    if (rv < 0)
        goto out_type;
    rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
    if (rv < 0)
        goto out_xfrm6;
    rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
    if (rv < 0)
        goto out_xfrm46;
    return 0;

out_xfrm46:
    xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
out_xfrm6:
    xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
out_type:
    unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
out_pernet:
    kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
    return rv;
}

static void __exit xfrm6_tunnel_fini(void)
{
    xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
    xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
    xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
    unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
    kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
}

module_init(xfrm6_tunnel_init);
module_exit(xfrm6_tunnel_fini);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);