[AH4] Harmonisation of output function

[AH4] Harmonisation of output function

[Herbert Xu]

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Hi Dave:

This is another step towards the union of the tunnel mode encapsulation
between transforms.  As there are significant differences between the
tunnel encapsulation of IPv4 and IPv6, I'll be dealing with IPv4 only
for now.

This particular patch rearranges the code in ah_output to isolate the
tunnel mode encapsulation.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

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===== net/ipv4/ah4.c 1.33 vs edited =====
--- 1.33/net/ipv4/ah4.c	2004-06-24 11:19:28 +10:00
+++ edited/net/ipv4/ah4.c	2004-07-02 22:53:20 +10:00
@@ -86,29 +86,23 @@
 		top_iph = (struct iphdr*)skb_push(*pskb, x->props.header_len);
 		top_iph->ihl = 5;
 		top_iph->version = 4;
-		top_iph->tos = 0;
-		top_iph->tot_len = htons((*pskb)->len);
-		top_iph->frag_off = 0;
+		top_iph->tos = iph->tos;
+		if (x->props.flags & XFRM_STATE_NOECN)
+			IP_ECN_clear(top_iph);
+		top_iph->frag_off = iph->frag_off & ~htons(IP_MF|IP_OFFSET);
 		if (!(iph->frag_off&htons(IP_DF)))
 			__ip_select_ident(top_iph, dst, 0);
-		top_iph->ttl = 0;
-		top_iph->protocol = IPPROTO_AH;
-		top_iph->check = 0;
+		top_iph->ttl = iph->ttl;
 		top_iph->saddr = x->props.saddr.a4;
 		top_iph->daddr = x->id.daddr.a4;
+		memcpy(&tmp_iph, top_iph, 20);
+		memset(&(IPCB(*pskb)->opt), 0, sizeof(struct ip_options));
 		ah = (struct ip_auth_hdr*)(top_iph+1);
 		ah->nexthdr = IPPROTO_IPIP;
 	} else {
 		memcpy(&tmp_iph, (*pskb)->data, iph->ihl*4);
 		top_iph = (struct iphdr*)skb_push(*pskb, x->props.header_len);
 		memcpy(top_iph, &tmp_iph, iph->ihl*4);
-		iph = &tmp_iph.iph;
-		top_iph->tos = 0;
-		top_iph->tot_len = htons((*pskb)->len);
-		top_iph->frag_off = 0;
-		top_iph->ttl = 0;
-		top_iph->protocol = IPPROTO_AH;
-		top_iph->check = 0;
 		if (top_iph->ihl != 5) {
 			err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
 			if (err)
@@ -117,6 +111,15 @@
 		ah = (struct ip_auth_hdr*)((char*)top_iph+iph->ihl*4);
 		ah->nexthdr = iph->protocol;
 	}
+
+	iph = &tmp_iph.iph;
+	top_iph->tos = 0;
+	top_iph->tot_len = htons((*pskb)->len);
+	top_iph->frag_off = 0;
+	top_iph->ttl = 0;
+	top_iph->protocol = IPPROTO_AH;
+	top_iph->check = 0;
+
 	ahp = x->data;
 	ah->hdrlen  = (XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + 
 				   ahp->icv_trunc_len) >> 2) - 2;
@@ -127,13 +130,8 @@
 	ahp->icv(ahp, *pskb, ah->auth_data);
 	top_iph->tos = iph->tos;
 	top_iph->ttl = iph->ttl;
-	if (x->props.mode) {
-		if (x->props.flags & XFRM_STATE_NOECN)
-			IP_ECN_clear(top_iph);
-		top_iph->frag_off = iph->frag_off&~htons(IP_MF|IP_OFFSET);
-		memset(&(IPCB(*pskb)->opt), 0, sizeof(struct ip_options));
-	} else {
-		top_iph->frag_off = iph->frag_off;
+	top_iph->frag_off = iph->frag_off;
+	if (!x->props.mode) {
 		top_iph->daddr = iph->daddr;
 		if (iph->ihl != 5)
 			memcpy(top_iph+1, iph+1, iph->ihl*4 - sizeof(struct iphdr));

Re: [AH4] Harmonisation of output function

[David S. Miller]

On Fri, 2 Jul 2004 23:06:52 +1000
Herbert Xu <herbert@gondor.apana.org.au> wrote:

> This is another step towards the union of the tunnel mode encapsulation
> between transforms.  As there are significant differences between the
> tunnel encapsulation of IPv4 and IPv6, I'll be dealing with IPv4 only
> for now.
> 
> This particular patch rearranges the code in ah_output to isolate the
> tunnel mode encapsulation.

Ok, applied.

Thanks.