text: /* SPDX-License-Identifier: GPL-2.0 */
  #ifndef _NET_FLOW_DISSECTOR_H
  #define _NET_FLOW_DISSECTOR_H
  
  #include <linux/types.h>
  #include <linux/in6.h>
  #include <uapi/linux/if_ether.h>
  
  /**
   * struct flow_dissector_key_control:
   * @thoff: Transport header offset
   */
  struct flow_dissector_key_control {
  	u16	thoff;
  	u16	addr_type;
  	u32	flags;
  };
  
  #define FLOW_DIS_IS_FRAGMENT	BIT(0)
  #define FLOW_DIS_FIRST_FRAG	BIT(1)
  #define FLOW_DIS_ENCAPSULATION	BIT(2)
  
  enum flow_dissect_ret {
  	FLOW_DISSECT_RET_OUT_GOOD,
  	FLOW_DISSECT_RET_OUT_BAD,
  	FLOW_DISSECT_RET_PROTO_AGAIN,
  	FLOW_DISSECT_RET_IPPROTO_AGAIN,
  	FLOW_DISSECT_RET_CONTINUE,
  };
  
  /**
   * struct flow_dissector_key_basic:
   * @thoff: Transport header offset
   * @n_proto: Network header protocol (eg. IPv4/IPv6)
   * @ip_proto: Transport header protocol (eg. TCP/UDP)
   */
  struct flow_dissector_key_basic {
  	__be16	n_proto;
  	u8	ip_proto;
  	u8	padding;
  };
  
  struct flow_dissector_key_tags {
  	u32	flow_label;
  };
  
  struct flow_dissector_key_vlan {
  	u16	vlan_id:12,
  		vlan_priority:3;
  	u16	padding;
  };
  
  struct flow_dissector_key_mpls {
  	u32	mpls_ttl:8,
  		mpls_bos:1,
  		mpls_tc:3,
  		mpls_label:20;
  };
  
  struct flow_dissector_key_keyid {
  	__be32	keyid;
  };
  
  /**
   * struct flow_dissector_key_ipv4_addrs:
   * @src: source ip address
   * @dst: destination ip address
   */
  struct flow_dissector_key_ipv4_addrs {
  	/* (src,dst) must be grouped, in the same way than in IP header */
  	__be32 src;
  	__be32 dst;
  };
  
  /**
   * struct flow_dissector_key_ipv6_addrs:
   * @src: source ip address
   * @dst: destination ip address
   */
  struct flow_dissector_key_ipv6_addrs {
  	/* (src,dst) must be grouped, in the same way than in IP header */
  	struct in6_addr src;
  	struct in6_addr dst;
  };
  
  /**
   * struct flow_dissector_key_tipc:
   * @key: source node address combined with selector
   */
  struct flow_dissector_key_tipc {
  	__be32 key;
  };
  
  /**
   * struct flow_dissector_key_addrs:
   * @v4addrs: IPv4 addresses
   * @v6addrs: IPv6 addresses
   */
  struct flow_dissector_key_addrs {
  	union {
  		struct flow_dissector_key_ipv4_addrs v4addrs;
  		struct flow_dissector_key_ipv6_addrs v6addrs;
  		struct flow_dissector_key_tipc tipckey;
  	};
  };
  
  /**
   * flow_dissector_key_arp:
   *	@ports: Operation, source and target addresses for an ARP header
   *              for Ethernet hardware addresses and IPv4 protocol addresses
   *		sip: Sender IP address
   *		tip: Target IP address
   *		op:  Operation
   *		sha: Sender hardware address
   *		tpa: Target hardware address
   */
  struct flow_dissector_key_arp {
  	__u32 sip;
  	__u32 tip;
  	__u8 op;
  	unsigned char sha[ETH_ALEN];
  	unsigned char tha[ETH_ALEN];
  };
  
  /**
   * flow_dissector_key_tp_ports:
   *	@ports: port numbers of Transport header
   *		src: source port number
   *		dst: destination port number
   */
  struct flow_dissector_key_ports {
  	union {
  		__be32 ports;
  		struct {
  			__be16 src;
  			__be16 dst;
  		};
  	};
  };
  
  /**
   * flow_dissector_key_icmp:
   *	@ports: type and code of ICMP header
   *		icmp: ICMP type (high) and code (low)
   *		type: ICMP type
   *		code: ICMP code
   */
  struct flow_dissector_key_icmp {
  	union {
  		__be16 icmp;
  		struct {
  			u8 type;
  			u8 code;
  		};
  	};
  };
  
  /**
   * struct flow_dissector_key_eth_addrs:
   * @src: source Ethernet address
   * @dst: destination Ethernet address
   */
  struct flow_dissector_key_eth_addrs {
  	/* (dst,src) must be grouped, in the same way than in ETH header */
  	unsigned char dst[ETH_ALEN];
  	unsigned char src[ETH_ALEN];
  };
  
  /**
   * struct flow_dissector_key_tcp:
   * @flags: flags
   */
  struct flow_dissector_key_tcp {
  	__be16 flags;
  };
  
  /**
   * struct flow_dissector_key_ip:
   * @tos: tos
   * @ttl: ttl
   */
  struct flow_dissector_key_ip {
  	__u8	tos;
  	__u8	ttl;
  };
  
  enum flow_dissector_key_id {
  	FLOW_DISSECTOR_KEY_CONTROL, /* struct flow_dissector_key_control */
  	FLOW_DISSECTOR_KEY_BASIC, /* struct flow_dissector_key_basic */
  	FLOW_DISSECTOR_KEY_IPV4_ADDRS, /* struct flow_dissector_key_ipv4_addrs */
  	FLOW_DISSECTOR_KEY_IPV6_ADDRS, /* struct flow_dissector_key_ipv6_addrs */
  	FLOW_DISSECTOR_KEY_PORTS, /* struct flow_dissector_key_ports */
  	FLOW_DISSECTOR_KEY_ICMP, /* struct flow_dissector_key_icmp */
  	FLOW_DISSECTOR_KEY_ETH_ADDRS, /* struct flow_dissector_key_eth_addrs */
  	FLOW_DISSECTOR_KEY_TIPC, /* struct flow_dissector_key_tipc */
  	FLOW_DISSECTOR_KEY_ARP, /* struct flow_dissector_key_arp */
  	FLOW_DISSECTOR_KEY_VLAN, /* struct flow_dissector_key_flow_vlan */
  	FLOW_DISSECTOR_KEY_FLOW_LABEL, /* struct flow_dissector_key_flow_tags */
  	FLOW_DISSECTOR_KEY_GRE_KEYID, /* struct flow_dissector_key_keyid */
  	FLOW_DISSECTOR_KEY_MPLS_ENTROPY, /* struct flow_dissector_key_keyid */
  	FLOW_DISSECTOR_KEY_ENC_KEYID, /* struct flow_dissector_key_keyid */
  	FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS, /* struct flow_dissector_key_ipv4_addrs */
  	FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS, /* struct flow_dissector_key_ipv6_addrs */
  	FLOW_DISSECTOR_KEY_ENC_CONTROL, /* struct flow_dissector_key_control */
  	FLOW_DISSECTOR_KEY_ENC_PORTS, /* struct flow_dissector_key_ports */
  	FLOW_DISSECTOR_KEY_MPLS, /* struct flow_dissector_key_mpls */
  	FLOW_DISSECTOR_KEY_TCP, /* struct flow_dissector_key_tcp */
  	FLOW_DISSECTOR_KEY_IP, /* struct flow_dissector_key_ip */
  
  	FLOW_DISSECTOR_KEY_MAX,
  };
  
  #define FLOW_DISSECTOR_F_PARSE_1ST_FRAG		BIT(0)
  #define FLOW_DISSECTOR_F_STOP_AT_L3		BIT(1)
  #define FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL	BIT(2)
  #define FLOW_DISSECTOR_F_STOP_AT_ENCAP		BIT(3)
  
  struct flow_dissector_key {
  	enum flow_dissector_key_id key_id;
  	size_t offset; /* offset of struct flow_dissector_key_*
  			  in target the struct */
  };
  
  struct flow_dissector {
  	unsigned int used_keys; /* each bit repesents presence of one key id */
  	unsigned short int offset[FLOW_DISSECTOR_KEY_MAX];
  };
  
  struct flow_keys {
  	struct flow_dissector_key_control control;
  #define FLOW_KEYS_HASH_START_FIELD basic
  	struct flow_dissector_key_basic basic;
  	struct flow_dissector_key_tags tags;
  	struct flow_dissector_key_vlan vlan;
  	struct flow_dissector_key_keyid keyid;
  	struct flow_dissector_key_ports ports;
  	struct flow_dissector_key_addrs addrs;
  };
  
  #define FLOW_KEYS_HASH_OFFSET		\
  	offsetof(struct flow_keys, FLOW_KEYS_HASH_START_FIELD)
  
  __be32 flow_get_u32_src(const struct flow_keys *flow);
  __be32 flow_get_u32_dst(const struct flow_keys *flow);
  
  extern struct flow_dissector flow_keys_dissector;
  extern struct flow_dissector flow_keys_buf_dissector;
  
  /* struct flow_keys_digest:
   *
   * This structure is used to hold a digest of the full flow keys. This is a
   * larger "hash" of a flow to allow definitively matching specific flows where
   * the 32 bit skb->hash is not large enough. The size is limited to 16 bytes so
   * that it can be used in CB of skb (see sch_choke for an example).
   */
  #define FLOW_KEYS_DIGEST_LEN	16
  struct flow_keys_digest {
  	u8	data[FLOW_KEYS_DIGEST_LEN];
  };
  
  void make_flow_keys_digest(struct flow_keys_digest *digest,
  			   const struct flow_keys *flow);
  
  static inline bool flow_keys_have_l4(const struct flow_keys *keys)
  {
  	return (keys->ports.ports || keys->tags.flow_label);
  }
  
  u32 flow_hash_from_keys(struct flow_keys *keys);
  
  static inline bool dissector_uses_key(const struct flow_dissector *flow_dissector,
  				      enum flow_dissector_key_id key_id)
  {
  	return flow_dissector->used_keys & (1 << key_id);
  }
  
  static inline 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];
  }
  
  #endif
  