+static inline int iphdr_ok(struct sk_buff *skb)
+{
+ int nh_ofs = skb_network_offset(skb);
+ if (skb->len >= nh_ofs + sizeof(struct iphdr)) {
+ int ip_len = ip_hdrlen(skb);
+ return (ip_len >= sizeof(struct iphdr)
+ && pskb_may_pull(skb, nh_ofs + ip_len));
+ }
+ return 0;
+}
+
+static inline int tcphdr_ok(struct sk_buff *skb)
+{
+ int th_ofs = skb_transport_offset(skb);
+ if (pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))) {
+ int tcp_len = tcp_hdrlen(skb);
+ return (tcp_len >= sizeof(struct tcphdr)
+ && skb->len >= th_ofs + tcp_len);
+ }
+ return 0;
+}
+
+static inline int udphdr_ok(struct sk_buff *skb)
+{
+ int th_ofs = skb_transport_offset(skb);
+ return pskb_may_pull(skb, th_ofs + sizeof(struct udphdr));
+}
+
+static inline int icmphdr_ok(struct sk_buff *skb)
+{
+ int th_ofs = skb_transport_offset(skb);
+ return pskb_may_pull(skb, th_ofs + sizeof(struct icmphdr));
+}
+
+#define TCP_FLAGS_OFFSET 13
+#define TCP_FLAG_MASK 0x3f
+
+static inline struct ofp_tcphdr *ofp_tcp_hdr(const struct sk_buff *skb)
+{
+ return (struct ofp_tcphdr *)skb_transport_header(skb);
+}
+