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linux/net/xfrm/xfrm_input.c
Steffen Klassert 2f32b51b60 xfrm: Introduce xfrm_input_afinfo to access the the callbacks properly 
IPv6 can be build as a module, so we need mechanism to access
the address family dependent callback functions properly.
Therefore we introduce xfrm_input_afinfo, similar to that
what we have for the address family dependent part of
policies and states.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2014-03-14 07:28:07 +01:00

382 lines
8.5 KiB
C
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/*
* xfrm_input.c
*
* Changes:
* YOSHIFUJI Hideaki @USAGI
* Split up af-specific portion
*
*/
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <net/dst.h>
#include <net/ip.h>
#include <net/xfrm.h>
static struct kmem_cache *secpath_cachep __read_mostly;
static DEFINE_SPINLOCK(xfrm_input_afinfo_lock);
static struct xfrm_input_afinfo __rcu *xfrm_input_afinfo[NPROTO];
int xfrm_input_register_afinfo(struct xfrm_input_afinfo *afinfo)
{
int err = 0;
if (unlikely(afinfo == NULL))
return -EINVAL;
if (unlikely(afinfo->family >= NPROTO))
return -EAFNOSUPPORT;
spin_lock_bh(&xfrm_input_afinfo_lock);
if (unlikely(xfrm_input_afinfo[afinfo->family] != NULL))
err = -ENOBUFS;
else
rcu_assign_pointer(xfrm_input_afinfo[afinfo->family], afinfo);
spin_unlock_bh(&xfrm_input_afinfo_lock);
return err;
}
EXPORT_SYMBOL(xfrm_input_register_afinfo);
int xfrm_input_unregister_afinfo(struct xfrm_input_afinfo *afinfo)
{
int err = 0;
if (unlikely(afinfo == NULL))
return -EINVAL;
if (unlikely(afinfo->family >= NPROTO))
return -EAFNOSUPPORT;
spin_lock_bh(&xfrm_input_afinfo_lock);
if (likely(xfrm_input_afinfo[afinfo->family] != NULL)) {
if (unlikely(xfrm_input_afinfo[afinfo->family] != afinfo))
err = -EINVAL;
else
RCU_INIT_POINTER(xfrm_input_afinfo[afinfo->family], NULL);
}
spin_unlock_bh(&xfrm_input_afinfo_lock);
synchronize_rcu();
return err;
}
EXPORT_SYMBOL(xfrm_input_unregister_afinfo);
static struct xfrm_input_afinfo *xfrm_input_get_afinfo(unsigned int family)
{
struct xfrm_input_afinfo *afinfo;
if (unlikely(family >= NPROTO))
return NULL;
rcu_read_lock();
afinfo = rcu_dereference(xfrm_input_afinfo[family]);
if (unlikely(!afinfo))
rcu_read_unlock();
return afinfo;
}
static void xfrm_input_put_afinfo(struct xfrm_input_afinfo *afinfo)
{
rcu_read_unlock();
}
static int xfrm_rcv_cb(struct sk_buff *skb, unsigned int family, u8 protocol,
int err)
{
int ret;
struct xfrm_input_afinfo *afinfo = xfrm_input_get_afinfo(family);
if (!afinfo)
return -EAFNOSUPPORT;
ret = afinfo->callback(skb, protocol, err);
xfrm_input_put_afinfo(afinfo);
return ret;
}
void __secpath_destroy(struct sec_path *sp)
{
int i;
for (i = 0; i < sp->len; i++)
xfrm_state_put(sp->xvec[i]);
kmem_cache_free(secpath_cachep, sp);
}
EXPORT_SYMBOL(__secpath_destroy);
struct sec_path *secpath_dup(struct sec_path *src)
{
struct sec_path *sp;
sp = kmem_cache_alloc(secpath_cachep, GFP_ATOMIC);
if (!sp)
return NULL;
sp->len = 0;
if (src) {
int i;
memcpy(sp, src, sizeof(*sp));
for (i = 0; i < sp->len; i++)
xfrm_state_hold(sp->xvec[i]);
}
atomic_set(&sp->refcnt, 1);
return sp;
}
EXPORT_SYMBOL(secpath_dup);
/* Fetch spi and seq from ipsec header */
int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
{
int offset, offset_seq;
int hlen;
switch (nexthdr) {
case IPPROTO_AH:
hlen = sizeof(struct ip_auth_hdr);
offset = offsetof(struct ip_auth_hdr, spi);
offset_seq = offsetof(struct ip_auth_hdr, seq_no);
break;
case IPPROTO_ESP:
hlen = sizeof(struct ip_esp_hdr);
offset = offsetof(struct ip_esp_hdr, spi);
offset_seq = offsetof(struct ip_esp_hdr, seq_no);
break;
case IPPROTO_COMP:
if (!pskb_may_pull(skb, sizeof(struct ip_comp_hdr)))
return -EINVAL;
*spi = htonl(ntohs(*(__be16 *)(skb_transport_header(skb) + 2)));
*seq = 0;
return 0;
default:
return 1;
}
if (!pskb_may_pull(skb, hlen))
return -EINVAL;
*spi = *(__be32 *)(skb_transport_header(skb) + offset);
*seq = *(__be32 *)(skb_transport_header(skb) + offset_seq);
return 0;
}
int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct xfrm_mode *inner_mode = x->inner_mode;
int err;
err = x->outer_mode->afinfo->extract_input(x, skb);
if (err)
return err;
if (x->sel.family == AF_UNSPEC) {
inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
if (inner_mode == NULL)
return -EAFNOSUPPORT;
}
skb->protocol = inner_mode->afinfo->eth_proto;
return inner_mode->input2(x, skb);
}
EXPORT_SYMBOL(xfrm_prepare_input);
int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
{
struct net *net = dev_net(skb->dev);
int err;
__be32 seq;
__be32 seq_hi;
struct xfrm_state *x = NULL;
xfrm_address_t *daddr;
struct xfrm_mode *inner_mode;
unsigned int family;
int decaps = 0;
int async = 0;
/* A negative encap_type indicates async resumption. */
if (encap_type < 0) {
async = 1;
x = xfrm_input_state(skb);
seq = XFRM_SKB_CB(skb)->seq.input.low;
family = x->outer_mode->afinfo->family;
goto resume;
}
daddr = (xfrm_address_t *)(skb_network_header(skb) +
XFRM_SPI_SKB_CB(skb)->daddroff);
family = XFRM_SPI_SKB_CB(skb)->family;
/* Allocate new secpath or COW existing one. */
if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
struct sec_path *sp;
sp = secpath_dup(skb->sp);
if (!sp) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
goto drop;
}
if (skb->sp)
secpath_put(skb->sp);
skb->sp = sp;
}
seq = 0;
if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
goto drop;
}
do {
if (skb->sp->len == XFRM_MAX_DEPTH) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
goto drop;
}
x = xfrm_state_lookup(net, skb->mark, daddr, spi, nexthdr, family);
if (x == NULL) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
xfrm_audit_state_notfound(skb, family, spi, seq);
goto drop;
}
skb->sp->xvec[skb->sp->len++] = x;
if (xfrm_tunnel_check(skb, x, family)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
goto drop;
}
spin_lock(&x->lock);
if (unlikely(x->km.state == XFRM_STATE_ACQ)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
goto drop_unlock;
}
if (unlikely(x->km.state != XFRM_STATE_VALID)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEINVALID);
goto drop_unlock;
}
if ((x->encap ? x->encap->encap_type : 0) != encap_type) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMISMATCH);
goto drop_unlock;
}
if (x->repl->check(x, skb, seq)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
goto drop_unlock;
}
if (xfrm_state_check_expire(x)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEEXPIRED);
goto drop_unlock;
}
spin_unlock(&x->lock);
seq_hi = htonl(xfrm_replay_seqhi(x, seq));
XFRM_SKB_CB(skb)->seq.input.low = seq;
XFRM_SKB_CB(skb)->seq.input.hi = seq_hi;
skb_dst_force(skb);
nexthdr = x->type->input(x, skb);
if (nexthdr == -EINPROGRESS)
return 0;
resume:
spin_lock(&x->lock);
if (nexthdr <= 0) {
if (nexthdr == -EBADMSG) {
xfrm_audit_state_icvfail(x, skb,
x->type->proto);
x->stats.integrity_failed++;
}
XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
goto drop_unlock;
}
/* only the first xfrm gets the encap type */
encap_type = 0;
if (async && x->repl->recheck(x, skb, seq)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
goto drop_unlock;
}
x->repl->advance(x, seq);
x->curlft.bytes += skb->len;
x->curlft.packets++;
spin_unlock(&x->lock);
XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;
inner_mode = x->inner_mode;
if (x->sel.family == AF_UNSPEC) {
inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
if (inner_mode == NULL)
goto drop;
}
if (inner_mode->input(x, skb)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
goto drop;
}
if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
decaps = 1;
break;
}
/*
* We need the inner address. However, we only get here for
* transport mode so the outer address is identical.
*/
daddr = &x->id.daddr;
family = x->outer_mode->afinfo->family;
err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
if (err < 0) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
goto drop;
}
} while (!err);
err = xfrm_rcv_cb(skb, family, x->type->proto, 0);
if (err)
goto drop;
nf_reset(skb);
if (decaps) {
skb_dst_drop(skb);
netif_rx(skb);
return 0;
} else {
return x->inner_mode->afinfo->transport_finish(skb, async);
}
drop_unlock:
spin_unlock(&x->lock);
drop:
xfrm_rcv_cb(skb, family, x && x->type ? x->type->proto : nexthdr, -1);
kfree_skb(skb);
return 0;
}
EXPORT_SYMBOL(xfrm_input);
int xfrm_input_resume(struct sk_buff *skb, int nexthdr)
{
return xfrm_input(skb, nexthdr, 0, -1);
}
EXPORT_SYMBOL(xfrm_input_resume);
void __init xfrm_input_init(void)
{
secpath_cachep = kmem_cache_create("secpath_cache",
sizeof(struct sec_path),
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
NULL);
}
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