[ESP4]: Merge NAT-T code in esp_output().

net/ipv4/esp4.c

@@ -28,9 +28,6 @@ int esp_output(struct sk_buff **pskb)
 	struct crypto_tfm *tfm;
 	struct esp_data *esp;
 	struct sk_buff *trailer;
-	struct udphdr *uh = NULL;
-	u32 *udpdata32;
-	struct xfrm_encap_tmpl *encap = NULL;
 	int blksize;
 	int clen;
 	int alen;
@@ -88,30 +85,10 @@ int esp_output(struct sk_buff **pskb)
 	*(u8*)(trailer->tail + clen-(*pskb)->len - 2) = (clen - (*pskb)->len)-2;
 	pskb_put(*pskb, trailer, clen - (*pskb)->len);
 
-	encap = x->encap;
-
 	iph = (*pskb)->nh.iph;
 	if (x->props.mode) {
 		top_iph = (struct iphdr*)skb_push(*pskb, x->props.header_len);
 		esph = (struct ip_esp_hdr*)(top_iph+1);
-		if (encap) {
-			switch (encap->encap_type) {
-			default:
-			case UDP_ENCAP_ESPINUDP:
-				uh = (struct udphdr*) esph;
-				esph = (struct ip_esp_hdr*)(uh+1);
-				top_iph->protocol = IPPROTO_UDP;
-				break;
-			case UDP_ENCAP_ESPINUDP_NON_IKE:
-				uh = (struct udphdr*) esph;
-				udpdata32 = (u32*)(uh+1);
-				udpdata32[0] = udpdata32[1] = 0;
-				esph = (struct ip_esp_hdr*)(udpdata32+2);
-				top_iph->protocol = IPPROTO_UDP;
-				break;
-			}
-		} else
-			top_iph->protocol = IPPROTO_ESP;
 		*(u8*)(trailer->tail - 1) = IPPROTO_IPIP;
 		top_iph->ihl = 5;
 		top_iph->version = 4;
@@ -131,24 +108,6 @@ int esp_output(struct sk_buff **pskb)
 		esph = (struct ip_esp_hdr*)skb_push(*pskb, x->props.header_len);
 		top_iph = (struct iphdr*)skb_push(*pskb, iph->ihl*4);
 		memcpy(top_iph, &tmp_iph, iph->ihl*4);
-		if (encap) {
-			switch (encap->encap_type) {
-			default:
-			case UDP_ENCAP_ESPINUDP:
-				uh = (struct udphdr*) esph;
-				esph = (struct ip_esp_hdr*)(uh+1);
-				top_iph->protocol = IPPROTO_UDP;
-				break;
-			case UDP_ENCAP_ESPINUDP_NON_IKE:
-				uh = (struct udphdr*) esph;
-				udpdata32 = (u32*)(uh+1);
-				udpdata32[0] = udpdata32[1] = 0;
-				esph = (struct ip_esp_hdr*)(udpdata32+2);
-				top_iph->protocol = IPPROTO_UDP;
-				break;
-			}
-		} else
-			top_iph->protocol = IPPROTO_ESP;
 		iph = &tmp_iph.iph;
 		top_iph->tot_len = htons((*pskb)->len + alen);
 		top_iph->check = 0;
@@ -157,13 +116,33 @@ int esp_output(struct sk_buff **pskb)
 	}
 
 	/* this is non-NULL only with UDP Encapsulation */
-	if (encap && uh) {
+	if (x->encap) {
+		struct xfrm_encap_tmpl *encap = x->encap;
+		struct udphdr *uh;
+		u32 *udpdata32;
+
+		uh = (struct udphdr *)esph;
 		uh->source = encap->encap_sport;
 		uh->dest = encap->encap_dport;
 		uh->len = htons((*pskb)->len + alen - sizeof(struct iphdr));
 		uh->check = 0;
+
+		switch (encap->encap_type) {
+		default:
+		case UDP_ENCAP_ESPINUDP:
+			esph = (struct ip_esp_hdr *)(uh + 1);
+			break;
+		case UDP_ENCAP_ESPINUDP_NON_IKE:
+			udpdata32 = (u32 *)(uh + 1);
+			udpdata32[0] = udpdata32[1] = 0;
+			esph = (struct ip_esp_hdr *)(udpdata32 + 2);
+			break;
 		}
 
+		top_iph->protocol = IPPROTO_UDP;
+	} else
+		top_iph->protocol = IPPROTO_ESP;
+
 	esph->spi = x->id.spi;
 	esph->seq_no = htonl(++x->replay.oseq);