Merge branch 'net-hash-tx'

Tom Herbert says:

====================
net: Improvements and applications of packet flow hash in transmit path

This patch series includes some patches which improve and make use
of skb->hash in the transmit path.

What is included:

- Infrastructure to save a precomputed hash in the sock structure.
  For connected TCP and UDP sockets we only need to compute the
  flow hash once and not once for every packet.
- Call skb_get_hash in get_xps_queue and __skb_tx_hash. This eliminates
  the awkward access to skb->sk->sk_hash in the lower transmit path.
- Move UDP source port generation into a common function in udp.h This
  implementation is mostly based on vxlan_src_port.
- Use non-zero IPv6 flow labels in flow_dissector as port information
  for flow hash calculation.
- Implement automatic flow label generation on transmit (per RFC 6438).
- Don't repeatedly try to compute an L4 hash in skb_get_hash if we've
  already tried to find one in software stack calculation.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/networking/ip-sysctl.txt

@@ -1132,6 +1132,15 @@ flowlabel_consistency - BOOLEAN
 	FALSE: disabled
 	Default: TRUE
 
+auto_flowlabels - BOOLEAN
+	Automatically generate flow labels based based on a flow hash
+	of the packet. This allows intermediate devices, such as routers,
+	to idenfify packet flows for mechanisms like Equal Cost Multipath
+	Routing (see RFC 6438).
+	TRUE: enabled
+	FALSE: disabled
+	Default: false
+
 anycast_src_echo_reply - BOOLEAN
 	Controls the use of anycast addresses as source addresses for ICMPv6
 	echo reply

drivers/net/vxlan.c

@@ -1570,25 +1570,6 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
 	return false;
 }
 
-/* Compute source port for outgoing packet
- *   first choice to use L4 flow hash since it will spread
- *     better and maybe available from hardware
- *   secondary choice is to use jhash on the Ethernet header
- */
-__be16 vxlan_src_port(__u16 port_min, __u16 port_max, struct sk_buff *skb)
-{
-	unsigned int range = (port_max - port_min) + 1;
-	u32 hash;
-
-	hash = skb_get_hash(skb);
-	if (!hash)
-		hash = jhash(skb->data, 2 * ETH_ALEN,
-			     (__force u32) skb->protocol);
-
-	return htons((((u64) hash * range) >> 32) + port_min);
-}
-EXPORT_SYMBOL_GPL(vxlan_src_port);
-
 static inline struct sk_buff *vxlan_handle_offloads(struct sk_buff *skb,
 						    bool udp_csum)
 {
@@ -1807,7 +1788,8 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 	if (tos == 1)
 		tos = ip_tunnel_get_dsfield(old_iph, skb);
 
-	src_port = vxlan_src_port(vxlan->port_min, vxlan->port_max, skb);
+	src_port = udp_flow_src_port(dev_net(dev), skb, vxlan->port_min,
+				     vxlan->port_max, true);
 
 	if (dst->sa.sa_family == AF_INET) {
 		memset(&fl4, 0, sizeof(fl4));
@@ -2235,7 +2217,6 @@ static void vxlan_setup(struct net_device *dev)
 {
 	struct vxlan_dev *vxlan = netdev_priv(dev);
 	unsigned int h;
-	int low, high;
 
 	eth_hw_addr_random(dev);
 	ether_setup(dev);
@@ -2272,9 +2253,6 @@ static void vxlan_setup(struct net_device *dev)
 	vxlan->age_timer.function = vxlan_cleanup;
 	vxlan->age_timer.data = (unsigned long) vxlan;
 
-	inet_get_local_port_range(dev_net(dev), &low, &high);
-	vxlan->port_min = low;
-	vxlan->port_max = high;
 	vxlan->dst_port = htons(vxlan_port);
 
 	vxlan->dev = dev;

include/linux/ipv6.h

@@ -199,7 +199,8 @@ struct ipv6_pinfo {
 						 * 010: prefer public address
 						 * 100: prefer care-of address
 						 */
-				dontfrag:1;
+				dontfrag:1,
+				autoflowlabel:1;
 	__u8			min_hopcount;
 	__u8			tclass;
 	__be32			rcv_flowinfo;

include/linux/netdevice.h

@@ -2486,7 +2486,7 @@ static inline int netif_set_xps_queue(struct net_device *dev,
  * as a distribution range limit for the returned value.
  */
 static inline u16 skb_tx_hash(const struct net_device *dev,
-			      const struct sk_buff *skb)
+			      struct sk_buff *skb)
 {
 	return __skb_tx_hash(dev, skb, dev->real_num_tx_queues);
 }

include/linux/skbuff.h

@@ -455,6 +455,7 @@ static inline u32 skb_mstamp_us_delta(const struct skb_mstamp *t1,
  *	@ooo_okay: allow the mapping of a socket to a queue to be changed
  *	@l4_hash: indicate hash is a canonical 4-tuple hash over transport
  *		ports.
+ *	@sw_hash: indicates hash was computed in software stack
  *	@wifi_acked_valid: wifi_acked was set
  *	@wifi_acked: whether frame was acked on wifi or not
  *	@no_fcs:  Request NIC to treat last 4 bytes as Ethernet FCS
@@ -562,6 +563,7 @@ struct sk_buff {
 	__u8			pfmemalloc:1;
 	__u8			ooo_okay:1;
 	__u8			l4_hash:1;
+	__u8			sw_hash:1;
 	__u8			wifi_acked_valid:1;
 	__u8			wifi_acked:1;
 	__u8			no_fcs:1;
@@ -575,7 +577,7 @@ struct sk_buff {
 	__u8			encap_hdr_csum:1;
 	__u8			csum_valid:1;
 	__u8			csum_complete_sw:1;
-	/* 3/5 bit hole (depending on ndisc_nodetype presence) */
+	/* 2/4 bit hole (depending on ndisc_nodetype presence) */
 	kmemcheck_bitfield_end(flags2);
 
 #if defined CONFIG_NET_DMA || defined CONFIG_NET_RX_BUSY_POLL
@@ -830,13 +832,14 @@ static inline void
 skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
 {
 	skb->l4_hash = (type == PKT_HASH_TYPE_L4);
+	skb->sw_hash = 0;
 	skb->hash = hash;
 }
 
 void __skb_get_hash(struct sk_buff *skb);
 static inline __u32 skb_get_hash(struct sk_buff *skb)
 {
-	if (!skb->l4_hash)
+	if (!skb->l4_hash && !skb->sw_hash)
 		__skb_get_hash(skb);
 
 	return skb->hash;
@@ -850,6 +853,7 @@ static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
 static inline void skb_clear_hash(struct sk_buff *skb)
 {
 	skb->hash = 0;
+	skb->sw_hash = 0;
 	skb->l4_hash = 0;
 }
 
@@ -862,6 +866,7 @@ static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
 static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
 {
 	to->hash = from->hash;
+	to->sw_hash = from->sw_hash;
 	to->l4_hash = from->l4_hash;
 };
 
@@ -3005,7 +3010,7 @@ static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
 	return skb->queue_mapping != 0;
 }
 
-u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb,
+u16 __skb_tx_hash(const struct net_device *dev, struct sk_buff *skb,
 		  unsigned int num_tx_queues);
 
 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)

include/net/flow_keys.h

@@ -29,4 +29,5 @@ struct flow_keys {
 
 bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow);
 __be32 skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto);
+u32 flow_hash_from_keys(struct flow_keys *keys);
 #endif

include/net/ip.h

@@ -31,6 +31,7 @@
 #include <net/route.h>
 #include <net/snmp.h>
 #include <net/flow.h>
+#include <net/flow_keys.h>
 
 struct sock;
 
@@ -353,6 +354,19 @@ static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
 				  skb->len, proto, 0);
 }
 
+static inline void inet_set_txhash(struct sock *sk)
+{
+	struct inet_sock *inet = inet_sk(sk);
+	struct flow_keys keys;
+
+	keys.src = inet->inet_saddr;
+	keys.dst = inet->inet_daddr;
+	keys.port16[0] = inet->inet_sport;
+	keys.port16[1] = inet->inet_dport;
+
+	sk->sk_txhash = flow_hash_from_keys(&keys);
+}
+
 /*
  *	Map a multicast IP onto multicast MAC for type ethernet.
  */

include/net/ipv6.h

@@ -19,6 +19,7 @@
 #include <net/if_inet6.h>
 #include <net/ndisc.h>
 #include <net/flow.h>
+#include <net/flow_keys.h>
 #include <net/snmp.h>
 
 #define SIN6_LEN_RFC2133	24
@@ -684,6 +685,40 @@ static inline int ip6_sk_dst_hoplimit(struct ipv6_pinfo *np, struct flowi6 *fl6,
 	return hlimit;
 }
 
+static inline void ip6_set_txhash(struct sock *sk)
+{
+	struct inet_sock *inet = inet_sk(sk);
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct flow_keys keys;
+
+	keys.src = (__force __be32)ipv6_addr_hash(&np->saddr);
+	keys.dst = (__force __be32)ipv6_addr_hash(&sk->sk_v6_daddr);
+	keys.port16[0] = inet->inet_sport;
+	keys.port16[1] = inet->inet_dport;
+
+	sk->sk_txhash = flow_hash_from_keys(&keys);
+}
+
+static inline __be32 ip6_make_flowlabel(struct net *net, struct sk_buff *skb,
+					__be32 flowlabel, bool autolabel)
+{
+	if (!flowlabel && (autolabel || net->ipv6.sysctl.auto_flowlabels)) {
+		__be32 hash;
+
+		hash = skb_get_hash(skb);
+
+		/* Since this is being sent on the wire obfuscate hash a bit
+		 * to minimize possbility that any useful information to an
+		 * attacker is leaked. Only lower 20 bits are relevant.
+		 */
+		hash ^= hash >> 12;
+
+		flowlabel = hash & IPV6_FLOWLABEL_MASK;
+	}
+
+	return flowlabel;
+}
+
 /*
  *	Header manipulation
  */

include/net/netns/ipv6.h

@@ -28,6 +28,7 @@ struct netns_sysctl_ipv6 {
 	int ip6_rt_mtu_expires;
 	int ip6_rt_min_advmss;
 	int flowlabel_consistency;
+	int auto_flowlabels;
 	int icmpv6_time;
 	int anycast_src_echo_reply;
 	int fwmark_reflect;

include/net/sock.h

@@ -273,6 +273,7 @@ struct cg_proto;
   *	@sk_rcvtimeo: %SO_RCVTIMEO setting
   *	@sk_sndtimeo: %SO_SNDTIMEO setting
   *	@sk_rxhash: flow hash received from netif layer
+  *	@sk_txhash: computed flow hash for use on transmit
   *	@sk_filter: socket filtering instructions
   *	@sk_protinfo: private area, net family specific, when not using slab
   *	@sk_timer: sock cleanup timer
@@ -347,6 +348,7 @@ struct sock {
 #ifdef CONFIG_RPS
 	__u32			sk_rxhash;
 #endif
+	__u32			sk_txhash;
 #ifdef CONFIG_NET_RX_BUSY_POLL
 	unsigned int		sk_napi_id;
 	unsigned int		sk_ll_usec;
@@ -1980,6 +1982,14 @@ static inline void sock_poll_wait(struct file *filp,
 	}
 }
 
+static inline void skb_set_hash_from_sk(struct sk_buff *skb, struct sock *sk)
+{
+	if (sk->sk_txhash) {
+		skb->l4_hash = 1;
+		skb->hash = sk->sk_txhash;
+	}
+}
+
 /*
  *	Queue a received datagram if it will fit. Stream and sequenced
  *	protocols can't normally use this as they need to fit buffers in
@@ -1994,6 +2004,7 @@ static inline void skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
 	skb_orphan(skb);
 	skb->sk = sk;
 	skb->destructor = sock_wfree;
+	skb_set_hash_from_sk(skb, sk);
 	/*
 	 * We used to take a refcount on sk, but following operation
 	 * is enough to guarantee sk_free() wont free this sock until

include/net/udp.h

@@ -176,6 +176,35 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum,
 		     int (*)(const struct sock *, const struct sock *),
 		     unsigned int hash2_nulladdr);
 
+static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
+				       int min, int max, bool use_eth)
+{
+	u32 hash;
+
+	if (min >= max) {
+		/* Use default range */
+		inet_get_local_port_range(net, &min, &max);
+	}
+
+	hash = skb_get_hash(skb);
+	if (unlikely(!hash) && use_eth) {
+		/* Can't find a normal hash, caller has indicated an Ethernet
+		 * packet so use that to compute a hash.
+		 */
+		hash = jhash(skb->data, 2 * ETH_ALEN,
+			     (__force u32) skb->protocol);
+	}
+
+	/* Since this is being sent on the wire obfuscate hash a bit
+	 * to minimize possbility that any useful information to an
+	 * attacker is leaked. Only upper 16 bits are relevant in the
+	 * computation for 16 bit port value.
+	 */
+	hash ^= hash << 16;
+
+	return htons((((u64) hash * (max - min)) >> 32) + min);
+}
+
 /* net/ipv4/udp.c */
 void udp_v4_early_demux(struct sk_buff *skb);
 int udp_get_port(struct sock *sk, unsigned short snum,

include/net/vxlan.h

@@ -45,8 +45,6 @@ int vxlan_xmit_skb(struct vxlan_sock *vs,
 		   __be32 src, __be32 dst, __u8 tos, __u8 ttl, __be16 df,
 		   __be16 src_port, __be16 dst_port, __be32 vni, bool xnet);
 
-__be16 vxlan_src_port(__u16 port_min, __u16 port_max, struct sk_buff *skb);
-
 /* IP header + UDP + VXLAN + Ethernet header */
 #define VXLAN_HEADROOM (20 + 8 + 8 + 14)
 /* IPv6 header + UDP + VXLAN + Ethernet header */

include/uapi/linux/in6.h

@@ -233,6 +233,7 @@ struct in6_flowlabel_req {
 #if 0	/* not yet */
 #define IPV6_USE_MIN_MTU	63
 #endif
+#define IPV6_AUTOFLOWLABEL	64
 
 /*
  * Netfilter (1)

net/core/flow_dissector.c

@@ -80,6 +80,8 @@ bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow)
 	case htons(ETH_P_IPV6): {
 		const struct ipv6hdr *iph;
 		struct ipv6hdr _iph;
+		__be32 flow_label;
+
 ipv6:
 		iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
 		if (!iph)
@@ -89,6 +91,21 @@ bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow)
 		flow->src = (__force __be32)ipv6_addr_hash(&iph->saddr);
 		flow->dst = (__force __be32)ipv6_addr_hash(&iph->daddr);
 		nhoff += sizeof(struct ipv6hdr);
+
+		flow_label = ip6_flowlabel(iph);
+		if (flow_label) {
+			/* Awesome, IPv6 packet has a flow label so we can
+			 * use that to represent the ports without any
+			 * further dissection.
+			 */
+			flow->n_proto = proto;
+			flow->ip_proto = ip_proto;
+			flow->ports = flow_label;
+			flow->thoff = (u16)nhoff;
+
+			return true;
+		}
+
 		break;
 	}
 	case htons(ETH_P_8021AD):
@@ -196,12 +213,33 @@ static __always_inline u32 __flow_hash_3words(u32 a, u32 b, u32 c)
 	return jhash_3words(a, b, c, hashrnd);
 }
 
-static __always_inline u32 __flow_hash_1word(u32 a)
+static inline u32 __flow_hash_from_keys(struct flow_keys *keys)
 {
-	__flow_hash_secret_init();
-	return jhash_1word(a, hashrnd);
+	u32 hash;
+
+	/* get a consistent hash (same value on both flow directions) */
+	if (((__force u32)keys->dst < (__force u32)keys->src) ||
+	    (((__force u32)keys->dst == (__force u32)keys->src) &&
+	     ((__force u16)keys->port16[1] < (__force u16)keys->port16[0]))) {
+		swap(keys->dst, keys->src);
+		swap(keys->port16[0], keys->port16[1]);
+	}
+
+	hash = __flow_hash_3words((__force u32)keys->dst,
+				  (__force u32)keys->src,
+				  (__force u32)keys->ports);
+	if (!hash)
+		hash = 1;
+
+	return hash;
 }
 
+u32 flow_hash_from_keys(struct flow_keys *keys)
+{
+	return __flow_hash_from_keys(keys);
+}
+EXPORT_SYMBOL(flow_hash_from_keys);
+
 /*
  * __skb_get_hash: calculate a flow hash based on src/dst addresses
  * and src/dst port numbers.  Sets hash in skb to non-zero hash value
@@ -211,7 +249,6 @@ static __always_inline u32 __flow_hash_1word(u32 a)
 void __skb_get_hash(struct sk_buff *skb)
 {
 	struct flow_keys keys;
-	u32 hash;
 
 	if (!skb_flow_dissect(skb, &keys))
 		return;
@@ -219,21 +256,9 @@ void __skb_get_hash(struct sk_buff *skb)
 	if (keys.ports)
 		skb->l4_hash = 1;
 
-	/* get a consistent hash (same value on both flow directions) */
-	if (((__force u32)keys.dst < (__force u32)keys.src) ||
-	    (((__force u32)keys.dst == (__force u32)keys.src) &&
-	     ((__force u16)keys.port16[1] < (__force u16)keys.port16[0]))) {
-		swap(keys.dst, keys.src);
-		swap(keys.port16[0], keys.port16[1]);
-	}
-
-	hash = __flow_hash_3words((__force u32)keys.dst,
-				  (__force u32)keys.src,
-				  (__force u32)keys.ports);
-	if (!hash)
-		hash = 1;
+	skb->sw_hash = 1;
 
-	skb->hash = hash;
+	skb->hash = __flow_hash_from_keys(&keys);
 }
 EXPORT_SYMBOL(__skb_get_hash);
 
@@ -241,7 +266,7 @@ EXPORT_SYMBOL(__skb_get_hash);
  * Returns a Tx hash based on the given packet descriptor a Tx queues' number
  * to be used as a distribution range.
  */
-u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb,
+u16 __skb_tx_hash(const struct net_device *dev, struct sk_buff *skb,
 		  unsigned int num_tx_queues)
 {
 	u32 hash;
@@ -261,13 +286,7 @@ u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb,
 		qcount = dev->tc_to_txq[tc].count;
 	}
 
-	if (skb->sk && skb->sk->sk_hash)
-		hash = skb->sk->sk_hash;
-	else
-		hash = (__force u16) skb->protocol;
-	hash = __flow_hash_1word(hash);
-
-	return (u16) (((u64) hash * qcount) >> 32) + qoffset;
+	return (u16) (((u64)skb_get_hash(skb) * qcount) >> 32) + qoffset;
 }
 EXPORT_SYMBOL(__skb_tx_hash);
 
@@ -339,17 +358,10 @@ static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
 		if (map) {
 			if (map->len == 1)
 				queue_index = map->queues[0];
-			else {
-				u32 hash;
-				if (skb->sk && skb->sk->sk_hash)
-					hash = skb->sk->sk_hash;
-				else
-					hash = (__force u16) skb->protocol ^
-					    skb->hash;
-				hash = __flow_hash_1word(hash);
+			else
 				queue_index = map->queues[
-				    ((u64)hash * map->len) >> 32];
-			}
+				    ((u64)skb_get_hash(skb) * map->len) >> 32];
+
 			if (unlikely(queue_index >= dev->real_num_tx_queues))
 				queue_index = -1;
 		}

net/ipv4/datagram.c

@@ -76,6 +76,7 @@ int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 	inet->inet_daddr = fl4->daddr;
 	inet->inet_dport = usin->sin_port;
 	sk->sk_state = TCP_ESTABLISHED;
+	inet_set_txhash(sk);
 	inet->inet_id = jiffies;
 
 	sk_dst_set(sk, &rt->dst);

net/ipv4/tcp_ipv4.c

@@ -208,6 +208,8 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 	inet->inet_dport = usin->sin_port;
 	inet->inet_daddr = daddr;
 
+	inet_set_txhash(sk);
+
 	inet_csk(sk)->icsk_ext_hdr_len = 0;
 	if (inet_opt)
 		inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
@@ -1334,6 +1336,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 	newinet->mc_ttl	      = ip_hdr(skb)->ttl;
 	newinet->rcv_tos      = ip_hdr(skb)->tos;
 	inet_csk(newsk)->icsk_ext_hdr_len = 0;
+	inet_set_txhash(newsk);
 	if (inet_opt)
 		inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
 	newinet->inet_id = newtp->write_seq ^ jiffies;

net/ipv4/tcp_output.c

@@ -916,6 +916,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
 	skb_orphan(skb);
 	skb->sk = sk;
 	skb->destructor = tcp_wfree;
+	skb_set_hash_from_sk(skb, sk);
 	atomic_add(skb->truesize, &sk->sk_wmem_alloc);
 
 	/* Build TCP header and checksum it. */

net/ipv6/af_inet6.c

@@ -765,6 +765,7 @@ static int __net_init inet6_net_init(struct net *net)
 	net->ipv6.sysctl.bindv6only = 0;
 	net->ipv6.sysctl.icmpv6_time = 1*HZ;
 	net->ipv6.sysctl.flowlabel_consistency = 1;
+	net->ipv6.sysctl.auto_flowlabels = 0;
 	atomic_set(&net->ipv6.rt_genid, 0);
 
 	err = ipv6_init_mibs(net);

net/ipv6/datagram.c

@@ -199,6 +199,7 @@ int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 		      NULL);
 
 	sk->sk_state = TCP_ESTABLISHED;
+	ip6_set_txhash(sk);
 out:
 	fl6_sock_release(flowlabel);
 	return err;

net/ipv6/ip6_gre.c

@@ -723,7 +723,8 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
 	 *	Push down and install the IP header.
 	 */
 	ipv6h = ipv6_hdr(skb);
-	ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield), fl6->flowlabel);
+	ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield),
+		     ip6_make_flowlabel(net, skb, fl6->flowlabel, false));
 	ipv6h->hop_limit = tunnel->parms.hop_limit;
 	ipv6h->nexthdr = proto;
 	ipv6h->saddr = fl6->saddr;
@@ -1174,7 +1175,9 @@ static int ip6gre_header(struct sk_buff *skb, struct net_device *dev,
 	struct ipv6hdr *ipv6h = (struct ipv6hdr *)skb_push(skb, t->hlen);
 	__be16 *p = (__be16 *)(ipv6h+1);
 
-	ip6_flow_hdr(ipv6h, 0, t->fl.u.ip6.flowlabel);
+	ip6_flow_hdr(ipv6h, 0,
+		     ip6_make_flowlabel(dev_net(dev), skb,
+					t->fl.u.ip6.flowlabel, false));
 	ipv6h->hop_limit = t->parms.hop_limit;
 	ipv6h->nexthdr = NEXTHDR_GRE;
 	ipv6h->saddr = t->parms.laddr;

net/ipv6/ip6_output.c

@@ -205,7 +205,8 @@ int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 	if (hlimit < 0)
 		hlimit = ip6_dst_hoplimit(dst);
 
-	ip6_flow_hdr(hdr, tclass, fl6->flowlabel);
+	ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel,
+						     np->autoflowlabel));
 
 	hdr->payload_len = htons(seg_len);
 	hdr->nexthdr = proto;
@@ -1569,7 +1570,9 @@ int ip6_push_pending_frames(struct sock *sk)
 	skb_reset_network_header(skb);
 	hdr = ipv6_hdr(skb);
 
-	ip6_flow_hdr(hdr, np->cork.tclass, fl6->flowlabel);
+	ip6_flow_hdr(hdr, np->cork.tclass,
+		     ip6_make_flowlabel(net, skb, fl6->flowlabel,
+					np->autoflowlabel));
 	hdr->hop_limit = np->cork.hop_limit;
 	hdr->nexthdr = proto;
 	hdr->saddr = fl6->saddr;

net/ipv6/ip6_tunnel.c

@@ -1046,7 +1046,8 @@ static int ip6_tnl_xmit2(struct sk_buff *skb,
 	skb_push(skb, sizeof(struct ipv6hdr));
 	skb_reset_network_header(skb);
 	ipv6h = ipv6_hdr(skb);
-	ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield), fl6->flowlabel);
+	ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield),
+		     ip6_make_flowlabel(net, skb, fl6->flowlabel, false));
 	ipv6h->hop_limit = t->parms.hop_limit;
 	ipv6h->nexthdr = proto;
 	ipv6h->saddr = fl6->saddr;

net/ipv6/ipv6_sockglue.c

@@ -834,6 +834,10 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
 		np->dontfrag = valbool;
 		retv = 0;
 		break;
+	case IPV6_AUTOFLOWLABEL:
+		np->autoflowlabel = valbool;
+		retv = 0;
+		break;
 	}
 
 	release_sock(sk);
@@ -1273,6 +1277,10 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
 		val = np->dontfrag;
 		break;
 
+	case IPV6_AUTOFLOWLABEL:
+		val = np->autoflowlabel;
+		break;
+
 	default:
 		return -ENOPROTOOPT;
 	}

net/ipv6/sysctl_net_ipv6.c

@@ -38,6 +38,13 @@ static struct ctl_table ipv6_table_template[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec
 	},
+	{
+		.procname	= "auto_flowlabels",
+		.data		= &init_net.ipv6.sysctl.auto_flowlabels,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec
+	},
 	{
 		.procname	= "fwmark_reflect",
 		.data		= &init_net.ipv6.sysctl.fwmark_reflect,
@@ -74,6 +81,7 @@ static int __net_init ipv6_sysctl_net_init(struct net *net)
 	ipv6_table[0].data = &net->ipv6.sysctl.bindv6only;
 	ipv6_table[1].data = &net->ipv6.sysctl.anycast_src_echo_reply;
 	ipv6_table[2].data = &net->ipv6.sysctl.flowlabel_consistency;
+	ipv6_table[3].data = &net->ipv6.sysctl.auto_flowlabels;
 
 	ipv6_route_table = ipv6_route_sysctl_init(net);
 	if (!ipv6_route_table)

net/ipv6/tcp_ipv6.c

@@ -198,6 +198,8 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 	sk->sk_v6_daddr = usin->sin6_addr;
 	np->flow_label = fl6.flowlabel;
 
+	ip6_set_txhash(sk);
+
 	/*
 	 *	TCP over IPv4
 	 */
@@ -1132,6 +1134,8 @@ static struct sock *tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 	newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr;
 	newsk->sk_bound_dev_if = ireq->ir_iif;
 
+	ip6_set_txhash(newsk);
+
 	/* Now IPv6 options...
 
 	   First: no IPv4 options.

net/openvswitch/vport-vxlan.c

@@ -143,8 +143,6 @@ static int vxlan_tnl_send(struct vport *vport, struct sk_buff *skb)
 	struct rtable *rt;
 	struct flowi4 fl;
 	__be16 src_port;
-	int port_min;
-	int port_max;
 	__be16 df;
 	int err;
 
@@ -172,8 +170,7 @@ static int vxlan_tnl_send(struct vport *vport, struct sk_buff *skb)
 
 	skb->ignore_df = 1;
 
-	inet_get_local_port_range(net, &port_min, &port_max);
-	src_port = vxlan_src_port(port_min, port_max, skb);
+	src_port = udp_flow_src_port(net, skb, 0, 0, true);
 
 	err = vxlan_xmit_skb(vxlan_port->vs, rt, skb,
 			     fl.saddr, OVS_CB(skb)->tun_key->ipv4_dst,