linux/net/ipv6/xfrm6_policy.c
Masahide NAKAMURA 59fbb3a61e [IPV6] MIP6: Loadable module support for MIPv6.
This patch makes MIPv6 loadable module named "mip6".

Here is a modprobe.conf(5) example to load it automatically
when user application uses XFRM state for MIPv6:

alias xfrm-type-10-43 mip6
alias xfrm-type-10-60 mip6

Some MIPv6 feature is not included by this modular, however,
it should not be affected to other features like either IPsec
or IPv6 with and without the patch.
We may discuss XFRM, MH (RAW socket) and ancillary data/sockopt
separately for future work.

Loadable features:
* MH receiving check (to send ICMP error back)
* RO header parsing and building (i.e. RH2 and HAO in DSTOPTS)
* XFRM policy/state database handling for RO

These are NOT covered as loadable:
* Home Address flags and its rule on source address selection
* XFRM sub policy (depends on its own kernel option)
* XFRM functions to receive RO as IPv6 extension header
* MH sending/receiving through raw socket if user application
  opens it (since raw socket allows to do so)
* RH2 sending as ancillary data
* RH2 operation with setsockopt(2)

Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-10 22:15:42 -07:00

437 lines
11 KiB
C

/*
* xfrm6_policy.c: based on xfrm4_policy.c
*
* Authors:
* Mitsuru KANDA @USAGI
* Kazunori MIYAZAWA @USAGI
* Kunihiro Ishiguro <kunihiro@ipinfusion.com>
* IPv6 support
* YOSHIFUJI Hideaki
* Split up af-specific portion
*
*/
#include <linux/compiler.h>
#include <linux/netdevice.h>
#include <net/addrconf.h>
#include <net/xfrm.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
#include <net/mip6.h>
#endif
static struct dst_ops xfrm6_dst_ops;
static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
static int xfrm6_dst_lookup(struct xfrm_dst **xdst, struct flowi *fl)
{
struct dst_entry *dst = ip6_route_output(NULL, fl);
int err = dst->error;
if (!err)
*xdst = (struct xfrm_dst *) dst;
else
dst_release(dst);
return err;
}
static int xfrm6_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
{
struct rt6_info *rt;
struct flowi fl_tunnel = {
.nl_u = {
.ip6_u = {
.daddr = *(struct in6_addr *)&daddr->a6,
},
},
};
if (!xfrm6_dst_lookup((struct xfrm_dst **)&rt, &fl_tunnel)) {
ipv6_get_saddr(&rt->u.dst, (struct in6_addr *)&daddr->a6,
(struct in6_addr *)&saddr->a6);
dst_release(&rt->u.dst);
return 0;
}
return -EHOSTUNREACH;
}
static struct dst_entry *
__xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
{
struct dst_entry *dst;
/* Still not clear if we should set fl->fl6_{src,dst}... */
read_lock_bh(&policy->lock);
for (dst = policy->bundles; dst; dst = dst->next) {
struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
struct in6_addr fl_dst_prefix, fl_src_prefix;
ipv6_addr_prefix(&fl_dst_prefix,
&fl->fl6_dst,
xdst->u.rt6.rt6i_dst.plen);
ipv6_addr_prefix(&fl_src_prefix,
&fl->fl6_src,
xdst->u.rt6.rt6i_src.plen);
if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
(xdst->u.rt6.rt6i_dst.plen != 128 ||
xdst->u.rt6.rt6i_src.plen != 128))) {
dst_clone(dst);
break;
}
}
read_unlock_bh(&policy->lock);
return dst;
}
static inline struct in6_addr*
__xfrm6_bundle_addr_remote(struct xfrm_state *x, struct in6_addr *addr)
{
return (x->type->remote_addr) ?
(struct in6_addr*)x->type->remote_addr(x, (xfrm_address_t *)addr) :
(struct in6_addr*)&x->id.daddr;
}
static inline struct in6_addr*
__xfrm6_bundle_addr_local(struct xfrm_state *x, struct in6_addr *addr)
{
return (x->type->local_addr) ?
(struct in6_addr*)x->type->local_addr(x, (xfrm_address_t *)addr) :
(struct in6_addr*)&x->props.saddr;
}
static inline void
__xfrm6_bundle_len_inc(int *len, int *nflen, struct xfrm_state *x)
{
if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
*nflen += x->props.header_len;
else
*len += x->props.header_len;
}
static inline void
__xfrm6_bundle_len_dec(int *len, int *nflen, struct xfrm_state *x)
{
if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
*nflen -= x->props.header_len;
else
*len -= x->props.header_len;
}
/* Allocate chain of dst_entry's, attach known xfrm's, calculate
* all the metrics... Shortly, bundle a bundle.
*/
static int
__xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
struct flowi *fl, struct dst_entry **dst_p)
{
struct dst_entry *dst, *dst_prev;
struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
struct rt6_info *rt = rt0;
struct flowi fl_tunnel = {
.nl_u = {
.ip6_u = {
.saddr = fl->fl6_src,
.daddr = fl->fl6_dst,
}
}
};
int i;
int err = 0;
int header_len = 0;
int nfheader_len = 0;
int trailer_len = 0;
dst = dst_prev = NULL;
dst_hold(&rt->u.dst);
for (i = 0; i < nx; i++) {
struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
struct xfrm_dst *xdst;
if (unlikely(dst1 == NULL)) {
err = -ENOBUFS;
dst_release(&rt->u.dst);
goto error;
}
if (!dst)
dst = dst1;
else {
dst_prev->child = dst1;
dst1->flags |= DST_NOHASH;
dst_clone(dst1);
}
xdst = (struct xfrm_dst *)dst1;
xdst->route = &rt->u.dst;
xdst->genid = xfrm[i]->genid;
if (rt->rt6i_node)
xdst->route_cookie = rt->rt6i_node->fn_sernum;
dst1->next = dst_prev;
dst_prev = dst1;
__xfrm6_bundle_len_inc(&header_len, &nfheader_len, xfrm[i]);
trailer_len += xfrm[i]->props.trailer_len;
if (xfrm[i]->props.mode == XFRM_MODE_TUNNEL ||
xfrm[i]->props.mode == XFRM_MODE_ROUTEOPTIMIZATION) {
unsigned short encap_family = xfrm[i]->props.family;
switch(encap_family) {
case AF_INET:
fl_tunnel.fl4_dst = xfrm[i]->id.daddr.a4;
fl_tunnel.fl4_src = xfrm[i]->props.saddr.a4;
break;
case AF_INET6:
ipv6_addr_copy(&fl_tunnel.fl6_dst, __xfrm6_bundle_addr_remote(xfrm[i], &fl->fl6_dst));
ipv6_addr_copy(&fl_tunnel.fl6_src, __xfrm6_bundle_addr_local(xfrm[i], &fl->fl6_src));
break;
default:
BUG_ON(1);
}
err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
&fl_tunnel, encap_family);
if (err)
goto error;
} else
dst_hold(&rt->u.dst);
}
dst_prev->child = &rt->u.dst;
dst->path = &rt->u.dst;
if (rt->rt6i_node)
((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
*dst_p = dst;
dst = dst_prev;
dst_prev = *dst_p;
i = 0;
for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
struct xfrm_state_afinfo *afinfo;
dst_prev->xfrm = xfrm[i++];
dst_prev->dev = rt->u.dst.dev;
if (rt->u.dst.dev)
dev_hold(rt->u.dst.dev);
dst_prev->obsolete = -1;
dst_prev->flags |= DST_HOST;
dst_prev->lastuse = jiffies;
dst_prev->header_len = header_len;
dst_prev->nfheader_len = nfheader_len;
dst_prev->trailer_len = trailer_len;
memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
/* Copy neighbour for reachability confirmation */
dst_prev->neighbour = neigh_clone(rt->u.dst.neighbour);
dst_prev->input = rt->u.dst.input;
/* XXX: When IPv4 is implemented as module and can be unloaded,
* we should manage reference to xfrm4_output in afinfo->output.
* Miyazawa
*/
afinfo = xfrm_state_get_afinfo(dst_prev->xfrm->props.family);
if (!afinfo) {
dst = *dst_p;
goto error;
}
dst_prev->output = afinfo->output;
xfrm_state_put_afinfo(afinfo);
/* Sheit... I remember I did this right. Apparently,
* it was magically lost, so this code needs audit */
x->u.rt6.rt6i_flags = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
x->u.rt6.rt6i_metric = rt0->rt6i_metric;
x->u.rt6.rt6i_node = rt0->rt6i_node;
x->u.rt6.rt6i_gateway = rt0->rt6i_gateway;
memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
x->u.rt6.rt6i_dst = rt0->rt6i_dst;
x->u.rt6.rt6i_src = rt0->rt6i_src;
x->u.rt6.rt6i_idev = rt0->rt6i_idev;
in6_dev_hold(rt0->rt6i_idev);
__xfrm6_bundle_len_dec(&header_len, &nfheader_len, x->u.dst.xfrm);
trailer_len -= x->u.dst.xfrm->props.trailer_len;
}
xfrm_init_pmtu(dst);
return 0;
error:
if (dst)
dst_free(dst);
return err;
}
static inline void
_decode_session6(struct sk_buff *skb, struct flowi *fl)
{
u16 offset = skb_network_header_len(skb);
struct ipv6hdr *hdr = ipv6_hdr(skb);
struct ipv6_opt_hdr *exthdr;
const unsigned char *nh = skb_network_header(skb);
u8 nexthdr = nh[IP6CB(skb)->nhoff];
memset(fl, 0, sizeof(struct flowi));
ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
nh = skb_network_header(skb);
exthdr = (struct ipv6_opt_hdr *)(nh + offset);
switch (nexthdr) {
case NEXTHDR_ROUTING:
case NEXTHDR_HOP:
case NEXTHDR_DEST:
offset += ipv6_optlen(exthdr);
nexthdr = exthdr->nexthdr;
exthdr = (struct ipv6_opt_hdr *)(nh + offset);
break;
case IPPROTO_UDP:
case IPPROTO_UDPLITE:
case IPPROTO_TCP:
case IPPROTO_SCTP:
case IPPROTO_DCCP:
if (pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
__be16 *ports = (__be16 *)exthdr;
fl->fl_ip_sport = ports[0];
fl->fl_ip_dport = ports[1];
}
fl->proto = nexthdr;
return;
case IPPROTO_ICMPV6:
if (pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
u8 *icmp = (u8 *)exthdr;
fl->fl_icmp_type = icmp[0];
fl->fl_icmp_code = icmp[1];
}
fl->proto = nexthdr;
return;
#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
case IPPROTO_MH:
if (pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
struct ip6_mh *mh;
mh = (struct ip6_mh *)exthdr;
fl->fl_mh_type = mh->ip6mh_type;
}
fl->proto = nexthdr;
return;
#endif
/* XXX Why are there these headers? */
case IPPROTO_AH:
case IPPROTO_ESP:
case IPPROTO_COMP:
default:
fl->fl_ipsec_spi = 0;
fl->proto = nexthdr;
return;
}
}
}
static inline int xfrm6_garbage_collect(void)
{
xfrm6_policy_afinfo.garbage_collect();
return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
}
static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
{
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
struct dst_entry *path = xdst->route;
path->ops->update_pmtu(path, mtu);
}
static void xfrm6_dst_destroy(struct dst_entry *dst)
{
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
if (likely(xdst->u.rt6.rt6i_idev))
in6_dev_put(xdst->u.rt6.rt6i_idev);
xfrm_dst_destroy(xdst);
}
static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
int unregister)
{
struct xfrm_dst *xdst;
if (!unregister)
return;
xdst = (struct xfrm_dst *)dst;
if (xdst->u.rt6.rt6i_idev->dev == dev) {
struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
BUG_ON(!loopback_idev);
do {
in6_dev_put(xdst->u.rt6.rt6i_idev);
xdst->u.rt6.rt6i_idev = loopback_idev;
in6_dev_hold(loopback_idev);
xdst = (struct xfrm_dst *)xdst->u.dst.child;
} while (xdst->u.dst.xfrm);
__in6_dev_put(loopback_idev);
}
xfrm_dst_ifdown(dst, dev);
}
static struct dst_ops xfrm6_dst_ops = {
.family = AF_INET6,
.protocol = __constant_htons(ETH_P_IPV6),
.gc = xfrm6_garbage_collect,
.update_pmtu = xfrm6_update_pmtu,
.destroy = xfrm6_dst_destroy,
.ifdown = xfrm6_dst_ifdown,
.gc_thresh = 1024,
.entry_size = sizeof(struct xfrm_dst),
};
static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
.family = AF_INET6,
.dst_ops = &xfrm6_dst_ops,
.dst_lookup = xfrm6_dst_lookup,
.get_saddr = xfrm6_get_saddr,
.find_bundle = __xfrm6_find_bundle,
.bundle_create = __xfrm6_bundle_create,
.decode_session = _decode_session6,
};
static void __init xfrm6_policy_init(void)
{
xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
}
static void xfrm6_policy_fini(void)
{
xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
}
void __init xfrm6_init(void)
{
xfrm6_policy_init();
xfrm6_state_init();
}
void xfrm6_fini(void)
{
//xfrm6_input_fini();
xfrm6_policy_fini();
xfrm6_state_fini();
}