[IPSEC]: Kill post_input hook and do NAT-T in esp_input directly
The only reason post_input exists at all is that it gives us the
potential to adjust the checksums incrementally in future which
we ought to do.
However, after thinking about it for a bit we can adjust the
checksums without using this post_input stuff at all. The crucial
point is that only the inner-most NAT-T SA needs to be considered
when adjusting checksums. What's more, the checksum adjustment
comes down to a single u32 due to the linearity of IP checksums.
We just happen to have a spare u32 lying around in our skb structure :)
When ip_summed is set to CHECKSUM_NONE on input, the value of skb->csum
is currently unused. All we have to do is to make that the checksum
adjustment and voila, there goes all the post_input and decap structures!
I've left in the decap data structures for now since it's intricately
woven into the sec_path stuff. We can kill them later too.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 3f47419..09590f3 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -12,13 +12,6 @@
#include <net/protocol.h>
#include <net/udp.h>
-/* decapsulation data for use when post-processing */
-struct esp_decap_data {
- xfrm_address_t saddr;
- __u16 sport;
- __u8 proto;
-};
-
static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
{
int err;
@@ -210,25 +203,47 @@
/* ... check padding bits here. Silly. :-) */
- if (x->encap && decap && decap->decap_type) {
- struct esp_decap_data *encap_data;
- struct udphdr *uh = (struct udphdr *) (iph+1);
+ if (x->encap) {
+ struct xfrm_encap_tmpl *encap = x->encap;
+ struct udphdr *uh;
- encap_data = (struct esp_decap_data *) (decap->decap_data);
- encap_data->proto = 0;
-
- switch (decap->decap_type) {
- case UDP_ENCAP_ESPINUDP:
- case UDP_ENCAP_ESPINUDP_NON_IKE:
- encap_data->proto = AF_INET;
- encap_data->saddr.a4 = iph->saddr;
- encap_data->sport = uh->source;
- encap_len = (void*)esph - (void*)uh;
- break;
-
- default:
+ if (encap->encap_type != decap->decap_type)
goto out;
+
+ uh = (struct udphdr *)(iph + 1);
+ encap_len = (void*)esph - (void*)uh;
+
+ /*
+ * 1) if the NAT-T peer's IP or port changed then
+ * advertize the change to the keying daemon.
+ * This is an inbound SA, so just compare
+ * SRC ports.
+ */
+ if (iph->saddr != x->props.saddr.a4 ||
+ uh->source != encap->encap_sport) {
+ xfrm_address_t ipaddr;
+
+ ipaddr.a4 = iph->saddr;
+ km_new_mapping(x, &ipaddr, uh->source);
+
+ /* XXX: perhaps add an extra
+ * policy check here, to see
+ * if we should allow or
+ * reject a packet from a
+ * different source
+ * address/port.
+ */
}
+
+ /*
+ * 2) ignore UDP/TCP checksums in case
+ * of NAT-T in Transport Mode, or
+ * perform other post-processing fixes
+ * as per draft-ietf-ipsec-udp-encaps-06,
+ * section 3.1.2
+ */
+ if (!x->props.mode)
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
}
iph->protocol = nexthdr[1];
@@ -245,63 +260,6 @@
return -EINVAL;
}
-static int esp_post_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
-{
-
- if (x->encap) {
- struct xfrm_encap_tmpl *encap;
- struct esp_decap_data *decap_data;
-
- encap = x->encap;
- decap_data = (struct esp_decap_data *)(decap->decap_data);
-
- /* first, make sure that the decap type == the encap type */
- if (encap->encap_type != decap->decap_type)
- return -EINVAL;
-
- switch (encap->encap_type) {
- default:
- case UDP_ENCAP_ESPINUDP:
- case UDP_ENCAP_ESPINUDP_NON_IKE:
- /*
- * 1) if the NAT-T peer's IP or port changed then
- * advertize the change to the keying daemon.
- * This is an inbound SA, so just compare
- * SRC ports.
- */
- if (decap_data->proto == AF_INET &&
- (decap_data->saddr.a4 != x->props.saddr.a4 ||
- decap_data->sport != encap->encap_sport)) {
- xfrm_address_t ipaddr;
-
- ipaddr.a4 = decap_data->saddr.a4;
- km_new_mapping(x, &ipaddr, decap_data->sport);
-
- /* XXX: perhaps add an extra
- * policy check here, to see
- * if we should allow or
- * reject a packet from a
- * different source
- * address/port.
- */
- }
-
- /*
- * 2) ignore UDP/TCP checksums in case
- * of NAT-T in Transport Mode, or
- * perform other post-processing fixes
- * as per * draft-ietf-ipsec-udp-encaps-06,
- * section 3.1.2
- */
- if (!x->props.mode)
- skb->ip_summed = CHECKSUM_UNNECESSARY;
-
- break;
- }
- }
- return 0;
-}
-
static u32 esp4_get_max_size(struct xfrm_state *x, int mtu)
{
struct esp_data *esp = x->data;
@@ -457,7 +415,6 @@
.destructor = esp_destroy,
.get_max_size = esp4_get_max_size,
.input = esp_input,
- .post_input = esp_post_input,
.output = esp_output
};
@@ -469,15 +426,6 @@
static int __init esp4_init(void)
{
- struct xfrm_decap_state decap;
-
- if (sizeof(struct esp_decap_data) >
- sizeof(decap.decap_data)) {
- extern void decap_data_too_small(void);
-
- decap_data_too_small();
- }
-
if (xfrm_register_type(&esp_type, AF_INET) < 0) {
printk(KERN_INFO "ip esp init: can't add xfrm type\n");
return -EAGAIN;