+static u16
+jme_udpsum(struct sk_buff *skb)
+{
+ u16 csum = 0xFFFFu;
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,21)
+ struct iphdr *iph;
+ int iphlen;
+ struct udphdr *udph;
+#endif
+
+ if (skb->len < (ETH_HLEN + sizeof(struct iphdr)))
+ return csum;
+ if (skb->protocol != htons(ETH_P_IP))
+ return csum;
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,21)
+ iph = (struct iphdr *)skb_pull(skb, ETH_HLEN);
+ iphlen = (iph->ihl << 2);
+ if ((iph->protocol != IPPROTO_UDP) ||
+ (skb->len < (iphlen + sizeof(struct udphdr)))) {
+ skb_push(skb, ETH_HLEN);
+ return csum;
+ }
+ udph = (struct udphdr *)skb_pull(skb, iphlen);
+ csum = udph->check;
+ skb_push(skb, iphlen);
+ skb_push(skb, ETH_HLEN);
+#else
+ skb_set_network_header(skb, ETH_HLEN);
+ if ((ip_hdr(skb)->protocol != IPPROTO_UDP) ||
+ (skb->len < (ETH_HLEN +
+ (ip_hdr(skb)->ihl << 2) +
+ sizeof(struct udphdr)))) {
+ skb_reset_network_header(skb);
+ return csum;
+ }
+ skb_set_transport_header(skb,
+ ETH_HLEN + (ip_hdr(skb)->ihl << 2));
+ csum = udp_hdr(skb)->check;
+ skb_reset_transport_header(skb);
+ skb_reset_network_header(skb);
+#endif
+
+ return csum;
+}
+