net/core/flow_dissector.c - linux - Git at Google

 #include <linux/kernel.h>
 #include <linux/skbuff.h>
 #include <linux/export.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/if_vlan.h>
 #include <net/ip.h>
 #include <net/ipv6.h>
 #include <linux/igmp.h>
 #include <linux/icmp.h>
 #include <linux/sctp.h>
 #include <linux/dccp.h>
 #include <linux/if_tunnel.h>
 #include <linux/if_pppox.h>
 #include <linux/ppp_defs.h>
 #include <linux/stddef.h>
 #include <linux/if_ether.h>
 #include <net/flow_dissector.h>
 #include <scsi/fc/fc_fcoe.h>

 static bool skb_flow_dissector_uses_key(struct flow_dissector *flow_dissector,
 					enum flow_dissector_key_id key_id)
 {
 	return flow_dissector->used_keys & (1 << key_id);
 }

 static void skb_flow_dissector_set_key(struct flow_dissector *flow_dissector,
 				       enum flow_dissector_key_id key_id)
 {
 	flow_dissector->used_keys |= (1 << key_id);
 }

 static void *skb_flow_dissector_target(struct flow_dissector *flow_dissector,
 				       enum flow_dissector_key_id key_id,
 				       void *target_container)
 {
 	return ((char *) target_container) + flow_dissector->offset[key_id];
 }

 void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
 			     const struct flow_dissector_key *key,
 			     unsigned int key_count)
 {
 	unsigned int i;

 	memset(flow_dissector, 0, sizeof(*flow_dissector));

 	for (i = 0; i < key_count; i++, key++) {
 		/* User should make sure that every key target offset is withing
 		 * boundaries of unsigned short.
 		 */
 		BUG_ON(key->offset > USHRT_MAX);
 		BUG_ON(skb_flow_dissector_uses_key(flow_dissector,
 						   key->key_id));

 		skb_flow_dissector_set_key(flow_dissector, key->key_id);
 		flow_dissector->offset[key->key_id] = key->offset;
 	}

 	/* Ensure that the dissector always includes basic key. That way
 	 * we are able to avoid handling lack of it in fast path.
 	 */
 	BUG_ON(!skb_flow_dissector_uses_key(flow_dissector,
 					    FLOW_DISSECTOR_KEY_BASIC));
 }
 EXPORT_SYMBOL(skb_flow_dissector_init);

 /**
  * __skb_flow_get_ports - extract the upper layer ports and return them
  * @skb: sk_buff to extract the ports from
  * @thoff: transport header offset
  * @ip_proto: protocol for which to get port offset
  * @data: raw buffer pointer to the packet, if NULL use skb->data
  * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
  *
  * The function will try to retrieve the ports at offset thoff + poff where poff
  * is the protocol port offset returned from proto_ports_offset
  */
 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
 			    void *data, int hlen)
 {
 	int poff = proto_ports_offset(ip_proto);

 	if (!data) {
 		data = skb->data;
 		hlen = skb_headlen(skb);
 	}

 	if (poff >= 0) {
 		__be32 *ports, _ports;

 		ports = __skb_header_pointer(skb, thoff + poff,
 					     sizeof(_ports), data, hlen, &_ports);
 		if (ports)
 			return *ports;
 	}

 	return 0;
 }
 EXPORT_SYMBOL(__skb_flow_get_ports);

 /**
  * __skb_flow_dissect - extract the flow_keys struct and return it
  * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
  * @flow_dissector: list of keys to dissect
  * @target_container: target structure to put dissected values into
  * @data: raw buffer pointer to the packet, if NULL use skb->data
  * @proto: protocol for which to get the flow, if @data is NULL use skb->protocol
  * @nhoff: network header offset, if @data is NULL use skb_network_offset(skb)
  * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
  *
  * The function will try to retrieve individual keys into target specified
  * by flow_dissector from either the skbuff or a raw buffer specified by the
  * rest parameters.
  *
  * Caller must take care of zeroing target container memory.
  */
 bool __skb_flow_dissect(const struct sk_buff *skb,
 			struct flow_dissector *flow_dissector,
 			void *target_container,
 			void *data, __be16 proto, int nhoff, int hlen)
 {
 	struct flow_dissector_key_basic *key_basic;
 	struct flow_dissector_key_addrs *key_addrs;
 	struct flow_dissector_key_ports *key_ports;
 	u8 ip_proto;

 	if (!data) {
 		data = skb->data;
 		proto = skb->protocol;
 		nhoff = skb_network_offset(skb);
 		hlen = skb_headlen(skb);
 	}

 	/* It is ensured by skb_flow_dissector_init() that basic key will
 	 * be always present.
 	 */
 	key_basic = skb_flow_dissector_target(flow_dissector,
 					      FLOW_DISSECTOR_KEY_BASIC,
 					      target_container);

 	if (skb_flow_dissector_uses_key(flow_dissector,
 					FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
 		struct ethhdr *eth = eth_hdr(skb);
 		struct flow_dissector_key_eth_addrs *key_eth_addrs;

 		key_eth_addrs = skb_flow_dissector_target(flow_dissector,
 							  FLOW_DISSECTOR_KEY_ETH_ADDRS,
 							  target_container);
 		memcpy(key_eth_addrs, &eth->h_dest, sizeof(*key_eth_addrs));
 	}

 again:
 	switch (proto) {
 	case htons(ETH_P_IP): {
 		const struct iphdr *iph;
 		struct iphdr _iph;
 ip:
 		iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
 		if (!iph || iph->ihl < 5)
 			return false;
 		nhoff += iph->ihl * 4;

 		ip_proto = iph->protocol;
 		if (ip_is_fragment(iph))
 			ip_proto = 0;

 		if (!skb_flow_dissector_uses_key(flow_dissector,
 						 FLOW_DISSECTOR_KEY_IPV4_ADDRS))
 			break;
 		key_addrs = skb_flow_dissector_target(flow_dissector,
 						      FLOW_DISSECTOR_KEY_IPV4_ADDRS,
 						      target_container);
 		memcpy(key_addrs, &iph->saddr, sizeof(*key_addrs));
 		break;
 	}
 	case htons(ETH_P_IPV6): {
 		const struct ipv6hdr *iph;
 		struct ipv6hdr _iph;
 		__be32 flow_label;

 ipv6:
 		iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
 		if (!iph)
 			return false;

 		ip_proto = iph->nexthdr;
 		nhoff += sizeof(struct ipv6hdr);

 		if (skb_flow_dissector_uses_key(flow_dissector,
 						FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS)) {
 			key_addrs = skb_flow_dissector_target(flow_dissector,
 							      FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS,
 							      target_container);

 			key_addrs->src = (__force __be32)ipv6_addr_hash(&iph->saddr);
 			key_addrs->dst = (__force __be32)ipv6_addr_hash(&iph->daddr);
 			goto flow_label;
 		}
 		if (skb_flow_dissector_uses_key(flow_dissector,
 						FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
 			struct flow_dissector_key_ipv6_addrs *key_ipv6_addrs;

 			key_ipv6_addrs = skb_flow_dissector_target(flow_dissector,
 								   FLOW_DISSECTOR_KEY_IPV6_ADDRS,
 								   target_container);

 			memcpy(key_ipv6_addrs, &iph->saddr, sizeof(*key_ipv6_addrs));
 			goto flow_label;
 		}
 		break;
 flow_label:
 		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.
 			 */

 			key_basic->n_proto = proto;
 			key_basic->ip_proto = ip_proto;
 			key_basic->thoff = (u16)nhoff;

 			if (!skb_flow_dissector_uses_key(flow_dissector,
 							 FLOW_DISSECTOR_KEY_PORTS))
 				break;
 			key_ports = skb_flow_dissector_target(flow_dissector,
 							      FLOW_DISSECTOR_KEY_PORTS,
 							      target_container);
 			key_ports->ports = flow_label;

 			return true;
 		}

 		break;
 	}
 	case htons(ETH_P_8021AD):
 	case htons(ETH_P_8021Q): {
 		const struct vlan_hdr *vlan;
 		struct vlan_hdr _vlan;

 		vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), data, hlen, &_vlan);
 		if (!vlan)
 			return false;

 		proto = vlan->h_vlan_encapsulated_proto;
 		nhoff += sizeof(*vlan);
 		goto again;
 	}
 	case htons(ETH_P_PPP_SES): {
 		struct {
 			struct pppoe_hdr hdr;
 			__be16 proto;
 		} *hdr, _hdr;
 		hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 		if (!hdr)
 			return false;
 		proto = hdr->proto;
 		nhoff += PPPOE_SES_HLEN;
 		switch (proto) {
 		case htons(PPP_IP):
 			goto ip;
 		case htons(PPP_IPV6):
 			goto ipv6;
 		default:
 			return false;
 		}
 	}
 	case htons(ETH_P_TIPC): {
 		struct {
 			__be32 pre[3];
 			__be32 srcnode;
 		} *hdr, _hdr;
 		hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 		if (!hdr)
 			return false;
 		key_basic->n_proto = proto;
 		key_basic->thoff = (u16)nhoff;

 		if (skb_flow_dissector_uses_key(flow_dissector,
 						FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS)) {
 			return true;
 			key_addrs = skb_flow_dissector_target(flow_dissector,
 							      FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS,
 							      target_container);
 			key_addrs->src = hdr->srcnode;
 			key_addrs->dst = 0;
 		}
 		return true;
 	}
 	case htons(ETH_P_FCOE):
 		key_basic->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
 		/* fall through */
 	default:
 		return false;
 	}

 	switch (ip_proto) {
 	case IPPROTO_GRE: {
 		struct gre_hdr {
 			__be16 flags;
 			__be16 proto;
 		} *hdr, _hdr;

 		hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 		if (!hdr)
 			return false;
 		/*
 		 * Only look inside GRE if version zero and no
 		 * routing
 		 */
 		if (!(hdr->flags & (GRE_VERSION|GRE_ROUTING))) {
 			proto = hdr->proto;
 			nhoff += 4;
 			if (hdr->flags & GRE_CSUM)
 				nhoff += 4;
 			if (hdr->flags & GRE_KEY)
 				nhoff += 4;
 			if (hdr->flags & GRE_SEQ)
 				nhoff += 4;
 			if (proto == htons(ETH_P_TEB)) {
 				const struct ethhdr *eth;
 				struct ethhdr _eth;

 				eth = __skb_header_pointer(skb, nhoff,
 							   sizeof(_eth),
 							   data, hlen, &_eth);
 				if (!eth)
 					return false;
 				proto = eth->h_proto;
 				nhoff += sizeof(*eth);
 			}
 			goto again;
 		}
 		break;
 	}
 	case IPPROTO_IPIP:
 		proto = htons(ETH_P_IP);
 		goto ip;
 	case IPPROTO_IPV6:
 		proto = htons(ETH_P_IPV6);
 		goto ipv6;
 	default:
 		break;
 	}

 	/* It is ensured by skb_flow_dissector_init() that basic key will
 	 * be always present.
 	 */
 	key_basic = skb_flow_dissector_target(flow_dissector,
 					      FLOW_DISSECTOR_KEY_BASIC,
 					      target_container);
 	key_basic->n_proto = proto;
 	key_basic->ip_proto = ip_proto;
 	key_basic->thoff = (u16) nhoff;

 	if (skb_flow_dissector_uses_key(flow_dissector,
 					FLOW_DISSECTOR_KEY_PORTS)) {
 		key_ports = skb_flow_dissector_target(flow_dissector,
 						      FLOW_DISSECTOR_KEY_PORTS,
 						      target_container);
 		key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto,
 							data, hlen);
 	}

 	return true;
 }
 EXPORT_SYMBOL(__skb_flow_dissect);

 static u32 hashrnd __read_mostly;
 static __always_inline void __flow_hash_secret_init(void)
 {
 	net_get_random_once(&hashrnd, sizeof(hashrnd));
 }

 static __always_inline u32 __flow_hash_3words(u32 a, u32 b, u32 c, u32 keyval)
 {
 	return jhash_3words(a, b, c, keyval);
 }

 static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval)
 {
 	u32 hash;

 	/* get a consistent hash (same value on both flow directions) */
 	if (((__force u32)keys->addrs.dst < (__force u32)keys->addrs.src) ||
 	    (((__force u32)keys->addrs.dst == (__force u32)keys->addrs.src) &&
 	     ((__force u16)keys->ports.port16[1] < (__force u16)keys->ports.port16[0]))) {
 		swap(keys->addrs.dst, keys->addrs.src);
 		swap(keys->ports.port16[0], keys->ports.port16[1]);
 	}

 	hash = __flow_hash_3words((__force u32)keys->addrs.dst,
 				  (__force u32)keys->addrs.src,
 				  (__force u32)keys->ports.ports,
 				  keyval);
 	if (!hash)
 		hash = 1;

 	return hash;
 }

 u32 flow_hash_from_keys(struct flow_keys *keys)
 {
 	__flow_hash_secret_init();
 	return __flow_hash_from_keys(keys, hashrnd);
 }
 EXPORT_SYMBOL(flow_hash_from_keys);

 static inline u32 ___skb_get_hash(const struct sk_buff *skb,
 				  struct flow_keys *keys, u32 keyval)
 {
 	if (!skb_flow_dissect_flow_keys(skb, keys))
 		return 0;

 	return __flow_hash_from_keys(keys, keyval);
 }

 struct _flow_keys_digest_data {
 	__be16	n_proto;
 	u8	ip_proto;
 	u8	padding;
 	__be32	ports;
 	__be32	src;
 	__be32	dst;
 };

 void make_flow_keys_digest(struct flow_keys_digest *digest,
 			   const struct flow_keys *flow)
 {
 	struct _flow_keys_digest_data *data =
 	    (struct _flow_keys_digest_data *)digest;

 	BUILD_BUG_ON(sizeof(*data) > sizeof(*digest));

 	memset(digest, 0, sizeof(*digest));

 	data->n_proto = flow->basic.n_proto;
 	data->ip_proto = flow->basic.ip_proto;
 	data->ports = flow->ports.ports;
 	data->src = flow->addrs.src;
 	data->dst = flow->addrs.dst;
 }
 EXPORT_SYMBOL(make_flow_keys_digest);

 /**
  * __skb_get_hash: calculate a flow hash
  * @skb: sk_buff to calculate flow hash from
  *
  * This function calculates a flow hash based on src/dst addresses
  * and src/dst port numbers.  Sets hash in skb to non-zero hash value
  * on success, zero indicates no valid hash.  Also, sets l4_hash in skb
  * if hash is a canonical 4-tuple hash over transport ports.
  */
 void __skb_get_hash(struct sk_buff *skb)
 {
 	struct flow_keys keys;
 	u32 hash;

 	__flow_hash_secret_init();

 	hash = ___skb_get_hash(skb, &keys, hashrnd);
 	if (!hash)
 		return;
 	if (keys.ports.ports)
 		skb->l4_hash = 1;
 	skb->sw_hash = 1;
 	skb->hash = hash;
 }
 EXPORT_SYMBOL(__skb_get_hash);

 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb)
 {
 	struct flow_keys keys;

 	return ___skb_get_hash(skb, &keys, perturb);
 }
 EXPORT_SYMBOL(skb_get_hash_perturb);

 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
 		   const struct flow_keys *keys, int hlen)
 {
 	u32 poff = keys->basic.thoff;

 	switch (keys->basic.ip_proto) {
 	case IPPROTO_TCP: {
 		/* access doff as u8 to avoid unaligned access */
 		const u8 *doff;
 		u8 _doff;

 		doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff),
 					    data, hlen, &_doff);
 		if (!doff)
 			return poff;

 		poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2);
 		break;
 	}
 	case IPPROTO_UDP:
 	case IPPROTO_UDPLITE:
 		poff += sizeof(struct udphdr);
 		break;
 	/* For the rest, we do not really care about header
 	 * extensions at this point for now.
 	 */
 	case IPPROTO_ICMP:
 		poff += sizeof(struct icmphdr);
 		break;
 	case IPPROTO_ICMPV6:
 		poff += sizeof(struct icmp6hdr);
 		break;
 	case IPPROTO_IGMP:
 		poff += sizeof(struct igmphdr);
 		break;
 	case IPPROTO_DCCP:
 		poff += sizeof(struct dccp_hdr);
 		break;
 	case IPPROTO_SCTP:
 		poff += sizeof(struct sctphdr);
 		break;
 	}

 	return poff;
 }

 /**
  * skb_get_poff - get the offset to the payload
  * @skb: sk_buff to get the payload offset from
  *
  * The function will get the offset to the payload as far as it could
  * be dissected.  The main user is currently BPF, so that we can dynamically
  * truncate packets without needing to push actual payload to the user
  * space and can analyze headers only, instead.
  */
 u32 skb_get_poff(const struct sk_buff *skb)
 {
 	struct flow_keys keys;

 	if (!skb_flow_dissect_flow_keys(skb, &keys))
 		return 0;

 	return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
 }

 static const struct flow_dissector_key flow_keys_dissector_keys[] = {
 	{
 		.key_id = FLOW_DISSECTOR_KEY_BASIC,
 		.offset = offsetof(struct flow_keys, basic),
 	},
 	{
 		.key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
 		.offset = offsetof(struct flow_keys, addrs),
 	},
 	{
 		.key_id = FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS,
 		.offset = offsetof(struct flow_keys, addrs),
 	},
 	{
 		.key_id = FLOW_DISSECTOR_KEY_PORTS,
 		.offset = offsetof(struct flow_keys, ports),
 	},
 };

 static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = {
 	{
 		.key_id = FLOW_DISSECTOR_KEY_BASIC,
 		.offset = offsetof(struct flow_keys, basic),
 	},
 };

 struct flow_dissector flow_keys_dissector __read_mostly;
 EXPORT_SYMBOL(flow_keys_dissector);

 struct flow_dissector flow_keys_buf_dissector __read_mostly;

 static int __init init_default_flow_dissectors(void)
 {
 	skb_flow_dissector_init(&flow_keys_dissector,
 				flow_keys_dissector_keys,
 				ARRAY_SIZE(flow_keys_dissector_keys));
 	skb_flow_dissector_init(&flow_keys_buf_dissector,
 				flow_keys_buf_dissector_keys,
 				ARRAY_SIZE(flow_keys_buf_dissector_keys));
 	return 0;
 }

 late_initcall_sync(init_default_flow_dissectors);
	#include <linux/kernel.h>
	#include <linux/skbuff.h>
	#include <linux/export.h>
	#include <linux/ip.h>
	#include <linux/ipv6.h>
	#include <linux/if_vlan.h>
	#include <net/ip.h>
	#include <net/ipv6.h>
	#include <linux/igmp.h>
	#include <linux/icmp.h>
	#include <linux/sctp.h>
	#include <linux/dccp.h>
	#include <linux/if_tunnel.h>
	#include <linux/if_pppox.h>
	#include <linux/ppp_defs.h>
	#include <linux/stddef.h>
	#include <linux/if_ether.h>
	#include <net/flow_dissector.h>
	#include <scsi/fc/fc_fcoe.h>

	static bool skb_flow_dissector_uses_key(struct flow_dissector *flow_dissector,
	enum flow_dissector_key_id key_id)
	{
	return flow_dissector->used_keys & (1 << key_id);
	}

	static void skb_flow_dissector_set_key(struct flow_dissector *flow_dissector,
	enum flow_dissector_key_id key_id)
	{
	flow_dissector->used_keys \|= (1 << key_id);
	}

	static void skb_flow_dissector_target(struct flow_dissector flow_dissector,
	enum flow_dissector_key_id key_id,
	void *target_container)
	{
	return ((char *) target_container) + flow_dissector->offset[key_id];
	}

	void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
	const struct flow_dissector_key *key,
	unsigned int key_count)
	{
	unsigned int i;

	memset(flow_dissector, 0, sizeof(*flow_dissector));

	for (i = 0; i < key_count; i++, key++) {
	/* User should make sure that every key target offset is withing
	* boundaries of unsigned short.
	*/
	BUG_ON(key->offset > USHRT_MAX);
	BUG_ON(skb_flow_dissector_uses_key(flow_dissector,
	key->key_id));

	skb_flow_dissector_set_key(flow_dissector, key->key_id);
	flow_dissector->offset[key->key_id] = key->offset;
	}

	/* Ensure that the dissector always includes basic key. That way
	* we are able to avoid handling lack of it in fast path.
	*/
	BUG_ON(!skb_flow_dissector_uses_key(flow_dissector,
	FLOW_DISSECTOR_KEY_BASIC));
	}
	EXPORT_SYMBOL(skb_flow_dissector_init);

	/**
	* __skb_flow_get_ports - extract the upper layer ports and return them
	* @skb: sk_buff to extract the ports from
	* @thoff: transport header offset
	* @ip_proto: protocol for which to get port offset
	* @data: raw buffer pointer to the packet, if NULL use skb->data
	* @hlen: packet header length, if @data is NULL use skb_headlen(skb)
	*
	* The function will try to retrieve the ports at offset thoff + poff where poff
	* is the protocol port offset returned from proto_ports_offset
	*/
	__be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
	void *data, int hlen)
	{
	int poff = proto_ports_offset(ip_proto);

	if (!data) {
	data = skb->data;
	hlen = skb_headlen(skb);
	}

	if (poff >= 0) {
	__be32 *ports, _ports;

	ports = __skb_header_pointer(skb, thoff + poff,
	sizeof(_ports), data, hlen, &_ports);
	if (ports)
	return *ports;
	}

	return 0;
	}
	EXPORT_SYMBOL(__skb_flow_get_ports);

	/**
	* __skb_flow_dissect - extract the flow_keys struct and return it
	* @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
	* @flow_dissector: list of keys to dissect
	* @target_container: target structure to put dissected values into
	* @data: raw buffer pointer to the packet, if NULL use skb->data
	* @proto: protocol for which to get the flow, if @data is NULL use skb->protocol
	* @nhoff: network header offset, if @data is NULL use skb_network_offset(skb)
	* @hlen: packet header length, if @data is NULL use skb_headlen(skb)
	*
	* The function will try to retrieve individual keys into target specified
	* by flow_dissector from either the skbuff or a raw buffer specified by the
	* rest parameters.
	*
	* Caller must take care of zeroing target container memory.
	*/
	bool __skb_flow_dissect(const struct sk_buff *skb,
	struct flow_dissector *flow_dissector,
	void *target_container,
	void *data, __be16 proto, int nhoff, int hlen)
	{
	struct flow_dissector_key_basic *key_basic;
	struct flow_dissector_key_addrs *key_addrs;
	struct flow_dissector_key_ports *key_ports;
	u8 ip_proto;

	if (!data) {
	data = skb->data;
	proto = skb->protocol;
	nhoff = skb_network_offset(skb);
	hlen = skb_headlen(skb);
	}

	/* It is ensured by skb_flow_dissector_init() that basic key will
	* be always present.
	*/
	key_basic = skb_flow_dissector_target(flow_dissector,
	FLOW_DISSECTOR_KEY_BASIC,
	target_container);

	if (skb_flow_dissector_uses_key(flow_dissector,
	FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
	struct ethhdr *eth = eth_hdr(skb);
	struct flow_dissector_key_eth_addrs *key_eth_addrs;

	key_eth_addrs = skb_flow_dissector_target(flow_dissector,
	FLOW_DISSECTOR_KEY_ETH_ADDRS,
	target_container);
	memcpy(key_eth_addrs, &eth->h_dest, sizeof(*key_eth_addrs));
	}

	again:
	switch (proto) {
	case htons(ETH_P_IP): {
	const struct iphdr *iph;
	struct iphdr _iph;
	ip:
	iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
	if (!iph \|\| iph->ihl < 5)
	return false;
	nhoff += iph->ihl * 4;

	ip_proto = iph->protocol;
	if (ip_is_fragment(iph))
	ip_proto = 0;

	if (!skb_flow_dissector_uses_key(flow_dissector,
	FLOW_DISSECTOR_KEY_IPV4_ADDRS))
	break;
	key_addrs = skb_flow_dissector_target(flow_dissector,
	FLOW_DISSECTOR_KEY_IPV4_ADDRS,
	target_container);
	memcpy(key_addrs, &iph->saddr, sizeof(*key_addrs));
	break;
	}
	case htons(ETH_P_IPV6): {
	const struct ipv6hdr *iph;
	struct ipv6hdr _iph;
	__be32 flow_label;

	ipv6:
	iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
	if (!iph)
	return false;

	ip_proto = iph->nexthdr;
	nhoff += sizeof(struct ipv6hdr);

	if (skb_flow_dissector_uses_key(flow_dissector,
	FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS)) {
	key_addrs = skb_flow_dissector_target(flow_dissector,
	FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS,
	target_container);

	key_addrs->src = (__force __be32)ipv6_addr_hash(&iph->saddr);
	key_addrs->dst = (__force __be32)ipv6_addr_hash(&iph->daddr);
	goto flow_label;
	}
	if (skb_flow_dissector_uses_key(flow_dissector,
	FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
	struct flow_dissector_key_ipv6_addrs *key_ipv6_addrs;

	key_ipv6_addrs = skb_flow_dissector_target(flow_dissector,
	FLOW_DISSECTOR_KEY_IPV6_ADDRS,
	target_container);

	memcpy(key_ipv6_addrs, &iph->saddr, sizeof(*key_ipv6_addrs));
	goto flow_label;
	}
	break;
	flow_label:
	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.
	*/

	key_basic->n_proto = proto;
	key_basic->ip_proto = ip_proto;
	key_basic->thoff = (u16)nhoff;

	if (!skb_flow_dissector_uses_key(flow_dissector,
	FLOW_DISSECTOR_KEY_PORTS))
	break;
	key_ports = skb_flow_dissector_target(flow_dissector,
	FLOW_DISSECTOR_KEY_PORTS,
	target_container);
	key_ports->ports = flow_label;

	return true;
	}

	break;
	}
	case htons(ETH_P_8021AD):
	case htons(ETH_P_8021Q): {
	const struct vlan_hdr *vlan;
	struct vlan_hdr _vlan;

	vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), data, hlen, &_vlan);
	if (!vlan)
	return false;

	proto = vlan->h_vlan_encapsulated_proto;
	nhoff += sizeof(*vlan);
	goto again;
	}
	case htons(ETH_P_PPP_SES): {
	struct {
	struct pppoe_hdr hdr;
	__be16 proto;
	} *hdr, _hdr;
	hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
	if (!hdr)
	return false;
	proto = hdr->proto;
	nhoff += PPPOE_SES_HLEN;
	switch (proto) {
	case htons(PPP_IP):
	goto ip;
	case htons(PPP_IPV6):
	goto ipv6;
	default:
	return false;
	}
	}
	case htons(ETH_P_TIPC): {
	struct {
	__be32 pre[3];
	__be32 srcnode;
	} *hdr, _hdr;
	hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
	if (!hdr)
	return false;
	key_basic->n_proto = proto;
	key_basic->thoff = (u16)nhoff;

	if (skb_flow_dissector_uses_key(flow_dissector,
	FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS)) {
	return true;
	key_addrs = skb_flow_dissector_target(flow_dissector,
	FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS,
	target_container);
	key_addrs->src = hdr->srcnode;
	key_addrs->dst = 0;
	}
	return true;
	}
	case htons(ETH_P_FCOE):
	key_basic->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
	/* fall through */
	default:
	return false;
	}

	switch (ip_proto) {
	case IPPROTO_GRE: {
	struct gre_hdr {
	__be16 flags;
	__be16 proto;
	} *hdr, _hdr;

	hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
	if (!hdr)
	return false;
	/*
	* Only look inside GRE if version zero and no
	* routing
	*/
	if (!(hdr->flags & (GRE_VERSION\|GRE_ROUTING))) {
	proto = hdr->proto;
	nhoff += 4;
	if (hdr->flags & GRE_CSUM)
	nhoff += 4;
	if (hdr->flags & GRE_KEY)
	nhoff += 4;
	if (hdr->flags & GRE_SEQ)
	nhoff += 4;
	if (proto == htons(ETH_P_TEB)) {
	const struct ethhdr *eth;
	struct ethhdr _eth;

	eth = __skb_header_pointer(skb, nhoff,
	sizeof(_eth),
	data, hlen, &_eth);
	if (!eth)
	return false;
	proto = eth->h_proto;
	nhoff += sizeof(*eth);
	}
	goto again;
	}
	break;
	}
	case IPPROTO_IPIP:
	proto = htons(ETH_P_IP);
	goto ip;
	case IPPROTO_IPV6:
	proto = htons(ETH_P_IPV6);
	goto ipv6;
	default:
	break;
	}

	/* It is ensured by skb_flow_dissector_init() that basic key will
	* be always present.
	*/
	key_basic = skb_flow_dissector_target(flow_dissector,
	FLOW_DISSECTOR_KEY_BASIC,
	target_container);
	key_basic->n_proto = proto;
	key_basic->ip_proto = ip_proto;
	key_basic->thoff = (u16) nhoff;

	if (skb_flow_dissector_uses_key(flow_dissector,
	FLOW_DISSECTOR_KEY_PORTS)) {
	key_ports = skb_flow_dissector_target(flow_dissector,
	FLOW_DISSECTOR_KEY_PORTS,
	target_container);
	key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto,
	data, hlen);
	}

	return true;
	}
	EXPORT_SYMBOL(__skb_flow_dissect);

	static u32 hashrnd __read_mostly;
	static __always_inline void __flow_hash_secret_init(void)
	{
	net_get_random_once(&hashrnd, sizeof(hashrnd));
	}

	static __always_inline u32 __flow_hash_3words(u32 a, u32 b, u32 c, u32 keyval)
	{
	return jhash_3words(a, b, c, keyval);
	}

	static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval)
	{
	u32 hash;

	/* get a consistent hash (same value on both flow directions) */
	if (((__force u32)keys->addrs.dst < (__force u32)keys->addrs.src) \|\|
	(((__force u32)keys->addrs.dst == (__force u32)keys->addrs.src) &&
	((__force u16)keys->ports.port16[1] < (__force u16)keys->ports.port16[0]))) {
	swap(keys->addrs.dst, keys->addrs.src);
	swap(keys->ports.port16[0], keys->ports.port16[1]);
	}

	hash = __flow_hash_3words((__force u32)keys->addrs.dst,
	(__force u32)keys->addrs.src,
	(__force u32)keys->ports.ports,
	keyval);
	if (!hash)
	hash = 1;

	return hash;
	}

	u32 flow_hash_from_keys(struct flow_keys *keys)
	{
	__flow_hash_secret_init();
	return __flow_hash_from_keys(keys, hashrnd);
	}
	EXPORT_SYMBOL(flow_hash_from_keys);

	static inline u32 ___skb_get_hash(const struct sk_buff *skb,
	struct flow_keys *keys, u32 keyval)
	{
	if (!skb_flow_dissect_flow_keys(skb, keys))
	return 0;

	return __flow_hash_from_keys(keys, keyval);
	}

	struct _flow_keys_digest_data {
	__be16 n_proto;
	u8 ip_proto;
	u8 padding;
	__be32 ports;
	__be32 src;
	__be32 dst;
	};

	void make_flow_keys_digest(struct flow_keys_digest *digest,
	const struct flow_keys *flow)
	{
	struct _flow_keys_digest_data *data =
	(struct _flow_keys_digest_data *)digest;

	BUILD_BUG_ON(sizeof(data) > sizeof(digest));

	memset(digest, 0, sizeof(*digest));

	data->n_proto = flow->basic.n_proto;
	data->ip_proto = flow->basic.ip_proto;
	data->ports = flow->ports.ports;
	data->src = flow->addrs.src;
	data->dst = flow->addrs.dst;
	}
	EXPORT_SYMBOL(make_flow_keys_digest);

	/**
	* __skb_get_hash: calculate a flow hash
	* @skb: sk_buff to calculate flow hash from
	*
	* This function calculates a flow hash based on src/dst addresses
	* and src/dst port numbers. Sets hash in skb to non-zero hash value
	* on success, zero indicates no valid hash. Also, sets l4_hash in skb
	* if hash is a canonical 4-tuple hash over transport ports.
	*/
	void __skb_get_hash(struct sk_buff *skb)
	{
	struct flow_keys keys;
	u32 hash;

	__flow_hash_secret_init();

	hash = ___skb_get_hash(skb, &keys, hashrnd);
	if (!hash)
	return;
	if (keys.ports.ports)
	skb->l4_hash = 1;
	skb->sw_hash = 1;
	skb->hash = hash;
	}
	EXPORT_SYMBOL(__skb_get_hash);

	__u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb)
	{
	struct flow_keys keys;

	return ___skb_get_hash(skb, &keys, perturb);
	}
	EXPORT_SYMBOL(skb_get_hash_perturb);

	u32 __skb_get_poff(const struct sk_buff skb, void data,
	const struct flow_keys *keys, int hlen)
	{
	u32 poff = keys->basic.thoff;

	switch (keys->basic.ip_proto) {
	case IPPROTO_TCP: {
	/* access doff as u8 to avoid unaligned access */
	const u8 *doff;
	u8 _doff;

	doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff),
	data, hlen, &_doff);
	if (!doff)
	return poff;

	poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2);
	break;
	}
	case IPPROTO_UDP:
	case IPPROTO_UDPLITE:
	poff += sizeof(struct udphdr);
	break;
	/* For the rest, we do not really care about header
	* extensions at this point for now.
	*/
	case IPPROTO_ICMP:
	poff += sizeof(struct icmphdr);
	break;
	case IPPROTO_ICMPV6:
	poff += sizeof(struct icmp6hdr);
	break;
	case IPPROTO_IGMP:
	poff += sizeof(struct igmphdr);
	break;
	case IPPROTO_DCCP:
	poff += sizeof(struct dccp_hdr);
	break;
	case IPPROTO_SCTP:
	poff += sizeof(struct sctphdr);
	break;
	}

	return poff;
	}

	/**
	* skb_get_poff - get the offset to the payload
	* @skb: sk_buff to get the payload offset from
	*
	* The function will get the offset to the payload as far as it could
	* be dissected. The main user is currently BPF, so that we can dynamically
	* truncate packets without needing to push actual payload to the user
	* space and can analyze headers only, instead.
	*/
	u32 skb_get_poff(const struct sk_buff *skb)
	{
	struct flow_keys keys;

	if (!skb_flow_dissect_flow_keys(skb, &keys))
	return 0;

	return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
	}

	static const struct flow_dissector_key flow_keys_dissector_keys[] = {
	{
	.key_id = FLOW_DISSECTOR_KEY_BASIC,
	.offset = offsetof(struct flow_keys, basic),
	},
	{
	.key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
	.offset = offsetof(struct flow_keys, addrs),
	},
	{
	.key_id = FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS,
	.offset = offsetof(struct flow_keys, addrs),
	},
	{
	.key_id = FLOW_DISSECTOR_KEY_PORTS,
	.offset = offsetof(struct flow_keys, ports),
	},
	};

	static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = {
	{
	.key_id = FLOW_DISSECTOR_KEY_BASIC,
	.offset = offsetof(struct flow_keys, basic),
	},
	};

	struct flow_dissector flow_keys_dissector __read_mostly;
	EXPORT_SYMBOL(flow_keys_dissector);

	struct flow_dissector flow_keys_buf_dissector __read_mostly;

	static int __init init_default_flow_dissectors(void)
	{
	skb_flow_dissector_init(&flow_keys_dissector,
	flow_keys_dissector_keys,
	ARRAY_SIZE(flow_keys_dissector_keys));
	skb_flow_dissector_init(&flow_keys_buf_dissector,
	flow_keys_buf_dissector_keys,
	ARRAY_SIZE(flow_keys_buf_dissector_keys));
	return 0;
	}

	late_initcall_sync(init_default_flow_dissectors);