linux/net/ipv4/xfrm4_policy.c
Herbert Xu 546be2405b [IPSEC] xfrm: Undo afinfo lock proliferation
The number of locks used to manage afinfo structures can easily be reduced
down to one each for policy and state respectively.  This is based on the
observation that the write locks are only held by module insertion/removal
which are very rare events so there is no need to further differentiate
between the insertion of modules like ipv6 versus esp6.

The removal of the read locks in xfrm4_policy.c/xfrm6_policy.c might look
suspicious at first.  However, after you realise that nobody ever takes
the corresponding write lock you'll feel better :)

As far as I can gather it's an attempt to guard against the removal of
the corresponding modules.  Since neither module can be unloaded at all
we can leave it to whoever fixes up IPv6 unloading :)

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:28:37 -07:00

321 lines
7.2 KiB
C

/*
* xfrm4_policy.c
*
* Changes:
* Kazunori MIYAZAWA @USAGI
* YOSHIFUJI Hideaki @USAGI
* Split up af-specific portion
*
*/
#include <linux/compiler.h>
#include <linux/config.h>
#include <linux/inetdevice.h>
#include <net/xfrm.h>
#include <net/ip.h>
static struct dst_ops xfrm4_dst_ops;
static struct xfrm_policy_afinfo xfrm4_policy_afinfo;
static int xfrm4_dst_lookup(struct xfrm_dst **dst, struct flowi *fl)
{
return __ip_route_output_key((struct rtable**)dst, fl);
}
static struct dst_entry *
__xfrm4_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
{
struct dst_entry *dst;
read_lock_bh(&policy->lock);
for (dst = policy->bundles; dst; dst = dst->next) {
struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
if (xdst->u.rt.fl.oif == fl->oif && /*XXX*/
xdst->u.rt.fl.fl4_dst == fl->fl4_dst &&
xdst->u.rt.fl.fl4_src == fl->fl4_src &&
xdst->u.rt.fl.fl4_tos == fl->fl4_tos &&
xfrm_bundle_ok(xdst, fl, AF_INET)) {
dst_clone(dst);
break;
}
}
read_unlock_bh(&policy->lock);
return dst;
}
/* Allocate chain of dst_entry's, attach known xfrm's, calculate
* all the metrics... Shortly, bundle a bundle.
*/
static int
__xfrm4_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 rtable *rt0 = (struct rtable*)(*dst_p);
struct rtable *rt = rt0;
u32 remote = fl->fl4_dst;
u32 local = fl->fl4_src;
struct flowi fl_tunnel = {
.nl_u = {
.ip4_u = {
.saddr = local,
.daddr = remote,
.tos = fl->fl4_tos
}
}
};
int i;
int err;
int header_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(&xfrm4_dst_ops);
struct xfrm_dst *xdst;
int tunnel = 0;
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;
dst1->next = dst_prev;
dst_prev = dst1;
if (xfrm[i]->props.mode) {
remote = xfrm[i]->id.daddr.a4;
local = xfrm[i]->props.saddr.a4;
tunnel = 1;
}
header_len += xfrm[i]->props.header_len;
trailer_len += xfrm[i]->props.trailer_len;
if (tunnel) {
fl_tunnel.fl4_src = local;
fl_tunnel.fl4_dst = remote;
err = xfrm_dst_lookup((struct xfrm_dst **)&rt,
&fl_tunnel, AF_INET);
if (err)
goto error;
} else
dst_hold(&rt->u.dst);
}
dst_prev->child = &rt->u.dst;
dst->path = &rt->u.dst;
*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;
x->u.rt.fl = *fl;
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->trailer_len = trailer_len;
memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
/* Copy neighbout for reachability confirmation */
dst_prev->neighbour = neigh_clone(rt->u.dst.neighbour);
dst_prev->input = rt->u.dst.input;
dst_prev->output = xfrm4_output;
if (rt->peer)
atomic_inc(&rt->peer->refcnt);
x->u.rt.peer = rt->peer;
/* Sheit... I remember I did this right. Apparently,
* it was magically lost, so this code needs audit */
x->u.rt.rt_flags = rt0->rt_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
x->u.rt.rt_type = rt->rt_type;
x->u.rt.rt_src = rt0->rt_src;
x->u.rt.rt_dst = rt0->rt_dst;
x->u.rt.rt_gateway = rt->rt_gateway;
x->u.rt.rt_spec_dst = rt0->rt_spec_dst;
x->u.rt.idev = rt0->idev;
in_dev_hold(rt0->idev);
header_len -= x->u.dst.xfrm->props.header_len;
trailer_len -= x->u.dst.xfrm->props.trailer_len;
}
xfrm_init_pmtu(dst);
return 0;
error:
if (dst)
dst_free(dst);
return err;
}
static void
_decode_session4(struct sk_buff *skb, struct flowi *fl)
{
struct iphdr *iph = skb->nh.iph;
u8 *xprth = skb->nh.raw + iph->ihl*4;
memset(fl, 0, sizeof(struct flowi));
if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) {
switch (iph->protocol) {
case IPPROTO_UDP:
case IPPROTO_TCP:
case IPPROTO_SCTP:
case IPPROTO_DCCP:
if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
u16 *ports = (u16 *)xprth;
fl->fl_ip_sport = ports[0];
fl->fl_ip_dport = ports[1];
}
break;
case IPPROTO_ICMP:
if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
u8 *icmp = xprth;
fl->fl_icmp_type = icmp[0];
fl->fl_icmp_code = icmp[1];
}
break;
case IPPROTO_ESP:
if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
u32 *ehdr = (u32 *)xprth;
fl->fl_ipsec_spi = ehdr[0];
}
break;
case IPPROTO_AH:
if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
u32 *ah_hdr = (u32*)xprth;
fl->fl_ipsec_spi = ah_hdr[1];
}
break;
case IPPROTO_COMP:
if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
u16 *ipcomp_hdr = (u16 *)xprth;
fl->fl_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
}
break;
default:
fl->fl_ipsec_spi = 0;
break;
};
}
fl->proto = iph->protocol;
fl->fl4_dst = iph->daddr;
fl->fl4_src = iph->saddr;
fl->fl4_tos = iph->tos;
}
static inline int xfrm4_garbage_collect(void)
{
xfrm4_policy_afinfo.garbage_collect();
return (atomic_read(&xfrm4_dst_ops.entries) > xfrm4_dst_ops.gc_thresh*2);
}
static void xfrm4_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 xfrm4_dst_destroy(struct dst_entry *dst)
{
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
if (likely(xdst->u.rt.idev))
in_dev_put(xdst->u.rt.idev);
xfrm_dst_destroy(xdst);
}
static void xfrm4_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.rt.idev->dev == dev) {
struct in_device *loopback_idev = in_dev_get(&loopback_dev);
BUG_ON(!loopback_idev);
do {
in_dev_put(xdst->u.rt.idev);
xdst->u.rt.idev = loopback_idev;
in_dev_hold(loopback_idev);
xdst = (struct xfrm_dst *)xdst->u.dst.child;
} while (xdst->u.dst.xfrm);
__in_dev_put(loopback_idev);
}
xfrm_dst_ifdown(dst, dev);
}
static struct dst_ops xfrm4_dst_ops = {
.family = AF_INET,
.protocol = __constant_htons(ETH_P_IP),
.gc = xfrm4_garbage_collect,
.update_pmtu = xfrm4_update_pmtu,
.destroy = xfrm4_dst_destroy,
.ifdown = xfrm4_dst_ifdown,
.gc_thresh = 1024,
.entry_size = sizeof(struct xfrm_dst),
};
static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
.family = AF_INET,
.dst_ops = &xfrm4_dst_ops,
.dst_lookup = xfrm4_dst_lookup,
.find_bundle = __xfrm4_find_bundle,
.bundle_create = __xfrm4_bundle_create,
.decode_session = _decode_session4,
};
static void __init xfrm4_policy_init(void)
{
xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
}
static void __exit xfrm4_policy_fini(void)
{
xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo);
}
void __init xfrm4_init(void)
{
xfrm4_state_init();
xfrm4_policy_init();
}