/*
* Copyright (C)2003-2006 Helsinki University of Technology
* Copyright (C)2003-2006 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:
* Noriaki TAKAMIYA @USAGI
* Masahide NAKAMURA @USAGI
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <net/sock.h>
#include <net/ipv6.h>
#include <net/ip6_checksum.h>
#include <net/xfrm.h>
#include <net/mip6.h>
static xfrm_address_t *mip6_xfrm_addr(struct xfrm_state *x, xfrm_address_t *addr)
{
return x->coaddr;
}
static inline unsigned int calc_padlen(unsigned int len, unsigned int n)
{
return (n - len + 16) & 0x7;
}
static inline void *mip6_padn(__u8 *data, __u8 padlen)
{
if (!data)
return NULL;
if (padlen == 1) {
data[0] = MIP6_OPT_PAD_1;
} else if (padlen > 1) {
data[0] = MIP6_OPT_PAD_N;
data[1] = padlen - 2;
if (padlen > 2)
memset(data+2, 0, data[1]);
}
return data + padlen;
}
static inline void mip6_param_prob(struct sk_buff *skb, int code, int pos)
{
icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev);
}
static int mip6_mh_len(int type)
{
int len = 0;
switch (type) {
case IP6_MH_TYPE_BRR:
len = 0;
break;
case IP6_MH_TYPE_HOTI:
case IP6_MH_TYPE_COTI:
case IP6_MH_TYPE_BU:
case IP6_MH_TYPE_BACK:
len = 1;
break;
case IP6_MH_TYPE_HOT:
case IP6_MH_TYPE_COT:
case IP6_MH_TYPE_BERROR:
len = 2;
break;
}
return len;
}
int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
{
struct ip6_mh *mh;
int mhlen;
if (!pskb_may_pull(skb, (skb->h.raw - skb->data) + 8) ||
!pskb_may_pull(skb, (skb->h.raw - skb->data) + ((skb->h.raw[1] + 1) << 3)))
return -1;
mh = (struct ip6_mh *)skb->h.raw;
if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) {
LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n",
mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type));
mip6_param_prob(skb, 0, (&mh->ip6mh_hdrlen) - skb->nh.raw);
return -1;
}
mhlen = (mh->ip6mh_hdrlen + 1) << 3;
if (skb->ip_summed == CHECKSUM_COMPLETE) {
skb->ip_summed = CHECKSUM_UNNECESSARY;
if (csum_ipv6_magic(&skb->nh.ipv6h->saddr,
&skb->nh.ipv6h->daddr,
mhlen, IPPROTO_MH,
skb->csum)) {
LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH hw checksum failed\n");
skb->ip_summed = CHECKSUM_NONE;
}
}
if (skb->ip_summed == CHECKSUM_NONE) {
if (csum_ipv6_magic(&skb->nh.ipv6h->saddr,
&skb->nh.ipv6h->daddr,
mhlen, IPPROTO_MH,
skb_checksum(skb, 0, mhlen, 0))) {
LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH checksum failed [%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x > %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x]\n",
NIP6(skb->nh.ipv6h->saddr),
NIP6(skb->nh.ipv6h->daddr));
return -1;
}
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
if (mh->ip6mh_proto != IPPROTO_NONE) {
LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n",
mh->ip6mh_proto);
mip6_param_prob(skb, 0, (&mh->ip6mh_proto) - skb->nh.raw);
return -1;
}
return 0;
}
static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipv6hdr *iph = skb->nh.ipv6h;
struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
!ipv6_addr_any((struct in6_addr *)x->coaddr))
return -ENOENT;
return destopt->nexthdr;
}
/* Destination Option Header is inserted.
* IP Header's src address is replaced with Home Address Option in
* Destination Option Header.
*/
static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipv6hdr *iph;
struct ipv6_destopt_hdr *dstopt;
struct ipv6_destopt_hao *hao;
u8 nexthdr;
int len;
iph = (struct ipv6hdr *)skb->data;
iph->payload_len = htons(skb->len - sizeof(*iph));
nexthdr = *skb->nh.raw;
*skb->nh.raw = IPPROTO_DSTOPTS;
dstopt = (struct ipv6_destopt_hdr *)skb->h.raw;
dstopt->nexthdr = nexthdr;
hao = mip6_padn((char *)(dstopt + 1),
calc_padlen(sizeof(*dstopt), 6));
hao->type = IPV6_TLV_HAO;
hao->length = sizeof(*hao) - 2;
BUG_TRAP(hao->length == 16);
len = ((char *)hao - (char *)dstopt) + sizeof(*hao);
memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
BUG_TRAP(len == x->props.header_len);
dstopt->hdrlen = (x->props.header_len >> 3) - 1;
return 0;
}
static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
u8 **nexthdr)
{
u16 offset = sizeof(struct ipv6hdr);
struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1);
unsigned int packet_len = skb->tail - skb->nh.raw;
int found_rhdr = 0;
*nexthdr = &skb->nh.ipv6h->nexthdr;
while (offset + 1 <= packet_len) {
switch (**nexthdr) {
case NEXTHDR_HOP:
break;
case NEXTHDR_ROUTING:
found_rhdr = 1;
break;
case NEXTHDR_DEST:
/*
* HAO MUST NOT appear more than once.
* XXX: It is better to try to find by the end of
* XXX: packet if HAO exists.
*/
if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n");
return offset;
}
if (found_rhdr)
return offset;
break;
default:
return offset;
}
offset += ipv6_optlen(exthdr);
*nexthdr = &exthdr->nexthdr;
exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
}
return offset;
}
static int mip6_destopt_init_state(struct xfrm_state *x)
{
if (x->id.spi) {
printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__,
x->id.spi);
return -EINVAL;
}
if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
printk(KERN_INFO "%s: state's mode is not %u: %u\n",
__FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
return -EINVAL;
}
x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
sizeof(struct ipv6_destopt_hao);
BUG_TRAP(x->props.header_len == 24);
return 0;
}
/*
* Do nothing about destroying since it has no specific operation for
* destination options header unlike IPsec protocols.
*/
static void mip6_destopt_destroy(struct xfrm_state *x)
{
}
static struct xfrm_type mip6_destopt_type =
{
.description = "MIP6DESTOPT",
.owner = THIS_MODULE,
.proto = IPPROTO_DSTOPTS,
.flags = XFRM_TYPE_NON_FRAGMENT,
.init_state = mip6_destopt_init_state,
.destructor = mip6_destopt_destroy,
.input = mip6_destopt_input,
.output = mip6_destopt_output,
.hdr_offset = mip6_destopt_offset,
.local_addr = mip6_xfrm_addr,
};
static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
if (!ipv6_addr_equal(&rt2->addr, (struct in6_addr *)x->coaddr) &&
!ipv6_addr_any((struct in6_addr *)x->coaddr))
return -ENOENT;
return rt2->rt_hdr.nexthdr;
}
/* Routing Header type 2 is inserted.
* IP Header's dst address is replaced with Routing Header's Home Address.
*/
static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipv6hdr *iph;
struct rt2_hdr *rt2;
u8 nexthdr;
iph = (struct ipv6hdr *)skb->data;
iph->payload_len = htons(skb->len - sizeof(*iph));
nexthdr = *skb->nh.raw;
*skb->nh.raw = IPPROTO_ROUTING;
rt2 = (struct rt2_hdr *)skb->h.raw;
rt2->rt_hdr.nexthdr = nexthdr;
rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
rt2->rt_hdr.segments_left = 1;
memset(&rt2->reserved, 0, sizeof(rt2->reserved));
BUG_TRAP(rt2->rt_hdr.hdrlen == 2);
memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
return 0;
}
static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
u8 **nexthdr)
{
u16 offset = sizeof(struct ipv6hdr);
struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1);
unsigned int packet_len = skb->tail - skb->nh.raw;
int found_rhdr = 0;
*nexthdr = &skb->nh.ipv6h->nexthdr;
while (offset + 1 <= packet_len) {
switch (**nexthdr) {
case NEXTHDR_HOP:
break;
case NEXTHDR_ROUTING:
if (offset + 3 <= packet_len) {
struct ipv6_rt_hdr *rt;
rt = (struct ipv6_rt_hdr *)(skb->nh.raw + offset);
if (rt->type != 0)
return offset;
}
found_rhdr = 1;
break;
case NEXTHDR_DEST:
if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
return offset;
if (found_rhdr)
return offset;
break;
default:
return offset;
}
offset += ipv6_optlen(exthdr);
*nexthdr = &exthdr->nexthdr;
exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
}
return offset;
}
static int mip6_rthdr_init_state(struct xfrm_state *x)
{
if (x->id.spi) {
printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__,
x->id.spi);
return -EINVAL;
}
if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
printk(KERN_INFO "%s: state's mode is not %u: %u\n",
__FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
return -EINVAL;
}
x->props.header_len = sizeof(struct rt2_hdr);
return 0;
}
/*
* Do nothing about destroying since it has no specific operation for routing
* header type 2 unlike IPsec protocols.
*/
static void mip6_rthdr_destroy(struct xfrm_state *x)
{
}
static struct xfrm_type mip6_rthdr_type =
{
.description = "MIP6RT",
.owner = THIS_MODULE,
.proto = IPPROTO_ROUTING,
.flags = XFRM_TYPE_NON_FRAGMENT,
.init_state = mip6_rthdr_init_state,
.destructor = mip6_rthdr_destroy,
.input = mip6_rthdr_input,
.output = mip6_rthdr_output,
.hdr_offset = mip6_rthdr_offset,
.remote_addr = mip6_xfrm_addr,
};
int __init mip6_init(void)
{
printk(KERN_INFO "Mobile IPv6\n");
if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __FUNCTION__);
goto mip6_destopt_xfrm_fail;
}
if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __FUNCTION__);
goto mip6_rthdr_xfrm_fail;
}
return 0;
mip6_rthdr_xfrm_fail:
xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
mip6_destopt_xfrm_fail:
return -EAGAIN;
}
void __exit mip6_fini(void)
{
if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __FUNCTION__);
if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __FUNCTION__);
}
