From 752c1f4c78fe86d0fd6497387f763306b0d8fc53 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 27 Feb 2006 13:00:40 -0800 Subject: [PATCH] [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 Signed-off-by: David S. Miller --- include/net/xfrm.h | 1 - net/ipv4/esp4.c | 128 ++++++++++++----------------------------- net/xfrm/xfrm_policy.c | 7 --- 3 files changed, 38 insertions(+), 98 deletions(-) diff --git a/include/net/xfrm.h b/include/net/xfrm.h index 004e645f3e18..8d362c49b8a9 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -233,7 +233,6 @@ struct xfrm_type int (*init_state)(struct xfrm_state *x); void (*destructor)(struct xfrm_state *); int (*input)(struct xfrm_state *, struct xfrm_decap_state *, struct sk_buff *skb); - int (*post_input)(struct xfrm_state *, struct xfrm_decap_state *, struct sk_buff *skb); int (*output)(struct xfrm_state *, struct sk_buff *pskb); /* Estimate maximal size of result of transformation of a dgram */ u32 (*get_max_size)(struct xfrm_state *, int size); diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c index 3f47419cb9c5..09590f356086 100644 --- a/net/ipv4/esp4.c +++ b/net/ipv4/esp4.c @@ -12,13 +12,6 @@ #include #include -/* 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 @@ static int esp_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struc /* ... 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); - - 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; + if (x->encap) { + struct xfrm_encap_tmpl *encap = x->encap; + struct udphdr *uh; - 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 @@ out: 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 @@ static struct xfrm_type esp_type = .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 struct net_protocol esp4_protocol = { 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; diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 8206025d8e46..ae62054a9fc4 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -996,13 +996,6 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb, struct sec_decap_state *xvec = &(skb->sp->x[i]); if (!xfrm_selector_match(&xvec->xvec->sel, &fl, family)) return 0; - - /* If there is a post_input processor, try running it */ - if (xvec->xvec->type->post_input && - (xvec->xvec->type->post_input)(xvec->xvec, - &(xvec->decap), - skb) != 0) - return 0; } } -- 2.20.1