+static unsigned int
+ovs_dst_get_mtu(const struct dst_entry *dst)
+{
+ return dst->dev->mtu;
+}
+
+static struct dst_ops ovs_dst_ops = {
+ .family = AF_UNSPEC,
+ .mtu = ovs_dst_get_mtu,
+};
+
+/* prepare_frag() is called once per (larger-than-MTU) frame; its inverse is
+ * ovs_vport_output(), which is called once per fragmented packet.
+ */
+static void prepare_frag(struct vport *vport, struct sk_buff *skb)
+{
+ unsigned int hlen = skb_network_offset(skb);
+ struct ovs_frag_data *data;
+
+ data = get_pcpu_ptr(ovs_frag_data_storage);
+ data->dst = (unsigned long) skb_dst(skb);
+ data->vport = vport;
+ data->cb = *OVS_GSO_CB(skb);
+ data->inner_protocol = ovs_skb_get_inner_protocol(skb);
+ data->vlan_tci = skb->vlan_tci;
+ data->vlan_proto = skb->vlan_proto;
+ data->l2_len = hlen;
+ memcpy(&data->l2_data, skb->data, hlen);
+
+ memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
+ skb_pull(skb, hlen);
+}
+
+static void ovs_fragment(struct vport *vport, struct sk_buff *skb, u16 mru,
+ __be16 ethertype)
+{
+ if (skb_network_offset(skb) > MAX_L2_LEN) {
+ OVS_NLERR(1, "L2 header too long to fragment");
+ goto err;
+ }
+
+ if (ethertype == htons(ETH_P_IP)) {
+ struct dst_entry ovs_dst;
+ unsigned long orig_dst;
+
+ prepare_frag(vport, skb);
+ dst_init(&ovs_dst, &ovs_dst_ops, NULL, 1,
+ DST_OBSOLETE_NONE, DST_NOCOUNT);
+ ovs_dst.dev = vport->dev;
+
+ orig_dst = (unsigned long) skb_dst(skb);
+ skb_dst_set_noref(skb, &ovs_dst);
+ IPCB(skb)->frag_max_size = mru;
+
+ ip_do_fragment(skb->sk, skb, ovs_vport_output);
+ refdst_drop(orig_dst);
+ } else if (ethertype == htons(ETH_P_IPV6)) {
+ const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
+ unsigned long orig_dst;
+ struct rt6_info ovs_rt;
+
+ if (!v6ops) {
+ goto err;
+ }
+
+ prepare_frag(vport, skb);
+ memset(&ovs_rt, 0, sizeof(ovs_rt));
+ dst_init(&ovs_rt.dst, &ovs_dst_ops, NULL, 1,
+ DST_OBSOLETE_NONE, DST_NOCOUNT);
+ ovs_rt.dst.dev = vport->dev;
+
+ orig_dst = (unsigned long) skb_dst(skb);
+ skb_dst_set_noref(skb, &ovs_rt.dst);
+ IP6CB(skb)->frag_max_size = mru;
+
+ v6ops->fragment(skb->sk, skb, ovs_vport_output);
+ refdst_drop(orig_dst);
+ } else {
+ WARN_ONCE(1, "Failed fragment ->%s: eth=%04x, MRU=%d, MTU=%d.",
+ ovs_vport_name(vport), ntohs(ethertype), mru,
+ vport->dev->mtu);
+ goto err;
+ }
+
+ return;
+err:
+ kfree_skb(skb);
+}
+#else /* < 3.10 */
+static void ovs_fragment(struct vport *vport, struct sk_buff *skb, u16 mru,
+ __be16 ethertype)
+{
+ WARN_ONCE(1, "Fragment unavailable ->%s: eth=%04x, MRU=%d, MTU=%d.",
+ ovs_vport_name(vport), ntohs(ethertype), mru,
+ vport->dev->mtu);
+ kfree_skb(skb);
+}
+#endif
+
+static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port,
+ struct sw_flow_key *key)
+{
+ struct vport *vport = ovs_vport_rcu(dp, out_port);
+
+ if (likely(vport)) {
+ u16 mru = OVS_CB(skb)->mru;
+
+ if (likely(!mru || (skb->len <= mru + ETH_HLEN))) {
+ ovs_vport_send(vport, skb);
+ } else if (mru <= vport->dev->mtu) {
+ __be16 ethertype = key->eth.type;
+
+ if (!is_flow_key_valid(key)) {
+ if (eth_p_mpls(skb->protocol))
+ ethertype = ovs_skb_get_inner_protocol(skb);
+ else
+ ethertype = vlan_get_protocol(skb);
+ }
+
+ ovs_fragment(vport, skb, mru, ethertype);
+ } else {
+ OVS_NLERR(true, "Cannot fragment IP frames");
+ kfree_skb(skb);
+ }
+ } else {
+ kfree_skb(skb);
+ }
+}