geneve: handle ipv6 priority like ipv4 tos

Other callers of udp_tunnel6_xmit_skb just pass 0 for the prio
argument.  Jesse Gross <jesse@nicira.com> suggested that prio is really
the same as IPv4's tos and should be handled the same, so this is my
interpretation of that suggestion.
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>
Reported-by: NJesse Gross <jesse@nicira.com>
Reviewed-by: NJesse Gross <jesse@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/geneve.c

@@ -763,6 +763,7 @@ static struct dst_entry *geneve_get_v6_dst(struct sk_buff *skb,
 	struct geneve_dev *geneve = netdev_priv(dev);
 	struct geneve_sock *gs6 = geneve->sock6;
 	struct dst_entry *dst = NULL;
+	__u8 prio;
 
 	memset(fl6, 0, sizeof(*fl6));
 	fl6->flowi6_mark = skb->mark;
@@ -771,7 +772,16 @@ static struct dst_entry *geneve_get_v6_dst(struct sk_buff *skb,
 	if (info) {
 		fl6->daddr = info->key.u.ipv6.dst;
 		fl6->saddr = info->key.u.ipv6.src;
+		fl6->flowi6_tos = RT_TOS(info->key.tos);
 	} else {
+		prio = geneve->tos;
+		if (prio == 1) {
+			const struct iphdr *iip = ip_hdr(skb);
+
+			prio = ip_tunnel_get_dsfield(iip, skb);
+		}
+
+		fl6->flowi6_tos = RT_TOS(prio);
 		fl6->daddr = geneve->remote.sin6.sin6_addr;
 	}
 
@@ -897,9 +907,10 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	struct geneve_dev *geneve = netdev_priv(dev);
 	struct geneve_sock *gs6 = geneve->sock6;
 	struct dst_entry *dst = NULL;
+	const struct iphdr *iip; /* interior IP header */
 	int err = -EINVAL;
 	struct flowi6 fl6;
-	__u8 ttl;
+	__u8 prio, ttl;
 	__be16 sport;
 	bool udp_csum;
 	bool xnet = !net_eq(geneve->net, dev_net(geneve->dev));
@@ -920,6 +931,8 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);
 	skb_reset_mac_header(skb);
 
+	iip = ip_hdr(skb);
+
 	if (info) {
 		const struct ip_tunnel_key *key = &info->key;
 		u8 *opts = NULL;
@@ -936,6 +949,7 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 		if (unlikely(err))
 			goto err;
 
+		prio = ip_tunnel_ecn_encap(key->tos, iip, skb);
 		ttl = key->ttl;
 	} else {
 		udp_csum = false;
@@ -944,13 +958,14 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 		if (unlikely(err))
 			goto err;
 
+		prio = ip_tunnel_ecn_encap(fl6.flowi6_tos, iip, skb);
 		ttl = geneve->ttl;
 		if (!ttl && ipv6_addr_is_multicast(&fl6.daddr))
 			ttl = 1;
 		ttl = ttl ? : ip6_dst_hoplimit(dst);
 	}
 	err = udp_tunnel6_xmit_skb(dst, gs6->sock->sk, skb, dev,
-				   &fl6.saddr, &fl6.daddr, 0, ttl,
+				   &fl6.saddr, &fl6.daddr, prio, ttl,
 				   sport, geneve->dst_port, !udp_csum);
 
 	iptunnel_xmit_stats(err, &dev->stats, dev->tstats);