+static int inet_gso_send_check(struct sk_buff *skb)
+{
+ struct iphdr *iph;
+ struct net_protocol *ops;
+ int proto;
+ int ihl;
+ int err = -EINVAL;
+
+ if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
+ goto out;
+
+ iph = skb->nh.iph;
+ ihl = iph->ihl * 4;
+ if (ihl < sizeof(*iph))
+ goto out;
+
+ if (unlikely(!pskb_may_pull(skb, ihl)))
+ goto out;
+
+ skb->h.raw = __skb_pull(skb, ihl);
+ iph = skb->nh.iph;
+ proto = iph->protocol & (MAX_INET_PROTOS - 1);
+ err = -EPROTONOSUPPORT;
+
+ rcu_read_lock();
+ ops = rcu_dereference(inet_protos[proto]);
+ if (likely(ops && ops->gso_send_check))
+ err = ops->gso_send_check(skb);
+ rcu_read_unlock();
+
+out:
+ return err;
+}
+
+static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int features)
+{
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ struct iphdr *iph;
+ struct net_protocol *ops;
+ int proto;
+ int ihl;
+ int id;
+
+ if (unlikely(skb_shinfo(skb)->gso_type &
+ ~(SKB_GSO_TCPV4 |
+ SKB_GSO_UDP |
+ SKB_GSO_DODGY |
+ SKB_GSO_TCP_ECN |
+ 0)))
+ goto out;
+
+ if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
+ goto out;
+
+ iph = skb->nh.iph;
+ ihl = iph->ihl * 4;
+ if (ihl < sizeof(*iph))
+ goto out;
+
+ if (unlikely(!pskb_may_pull(skb, ihl)))
+ goto out;
+
+ skb->h.raw = __skb_pull(skb, ihl);
+ iph = skb->nh.iph;
+ id = ntohs(iph->id);
+ proto = iph->protocol & (MAX_INET_PROTOS - 1);
+ segs = ERR_PTR(-EPROTONOSUPPORT);
+
+ rcu_read_lock();
+ ops = rcu_dereference(inet_protos[proto]);
+ if (likely(ops && ops->gso_segment))
+ segs = ops->gso_segment(skb, features);
+ rcu_read_unlock();
+
+ if (!segs || unlikely(IS_ERR(segs)))
+ goto out;
+
+ skb = segs;
+ do {
+ iph = skb->nh.iph;
+ iph->id = htons(id++);
+ iph->tot_len = htons(skb->len - skb->mac_len);
+ iph->check = 0;
+ iph->check = ip_fast_csum(skb->nh.raw, iph->ihl);
+ } while ((skb = skb->next));
+
+out:
+ return segs;
+}
+