OVS中的key解析

OVS在处理每条流的时候，先根据每条流生产相应的key，然后根据key匹配相应的流表，根据流表中的action操作来处理每条流，本文对key的结构体进行分析，看看对于一条流会提出那些特征信息。对于key的描述在openvswitch源码中的flow.h文件中。

struct sw_flow_key {
	u8 tun_opts[255];
	u8 tun_opts_len;
	struct ip_tunnel_key tun_key;  /* Encapsulating tunnel key. */
	struct {
		u32	priority;	/* Packet QoS priority. */
		u32	skb_mark;	/* SKB mark. */
		u16	in_port;	/* Input switch port (or DP_MAX_PORTS). */
	} __packed phy; /* Safe when right after 'tun_key'. */
	u8 mac_proto;			/* MAC layer protocol (e.g. Ethernet). */
	u8 tun_proto;                   /* Protocol of encapsulating tunnel. */
	u32 ovs_flow_hash;		/* Datapath computed hash value.  */
	u32 recirc_id;			/* Recirculation ID.  */
	struct {
		u8     src[ETH_ALEN];	/* Ethernet source address. */
		u8     dst[ETH_ALEN];	/* Ethernet destination address. */
		struct vlan_head vlan;
		struct vlan_head cvlan;
		__be16 type;		/* Ethernet frame type. */
	} eth;
	/* Filling a hole of two bytes. */
	u8 ct_state;
	u8 ct_orig_proto;		/* CT original direction tuple IP
					 * protocol.
					 */
	union {
		struct {
			__be32 top_lse;	/* top label stack entry */
		} mpls;
		struct {
			u8     proto;	/* IP protocol or lower 8 bits of ARP opcode. */
			u8     tos;	    /* IP ToS. */
			u8     ttl;	    /* IP TTL/hop limit. */
			u8     frag;	/* One of OVS_FRAG_TYPE_*. */
		} ip;
	};
	u16 ct_zone;			/* Conntrack zone. */
	struct {
		__be16 src;		/* TCP/UDP/SCTP source port. */
		__be16 dst;		/* TCP/UDP/SCTP destination port. */
		__be16 flags;		/* TCP flags. */
	} tp;
	union {
		struct {
			struct {
				__be32 src;	/* IP source address. */
				__be32 dst;	/* IP destination address. */
			} addr;
			union {
				struct {
					__be32 src;
					__be32 dst;
				} ct_orig;	/* Conntrack original direction fields. */
				struct {
					u8 sha[ETH_ALEN];	/* ARP source hardware address. */
					u8 tha[ETH_ALEN];	/* ARP target hardware address. */
				} arp;
			};
		} ipv4;
		struct {
			struct {
				struct in6_addr src;	/* IPv6 source address. */
				struct in6_addr dst;	/* IPv6 destination address. */
			} addr;
			__be32 label;			/* IPv6 flow label. */
			union {
				struct {
					struct in6_addr src;
					struct in6_addr dst;
				} ct_orig;	/* Conntrack original direction fields. */
				struct {
					struct in6_addr target;	/* ND target address. */
					u8 sll[ETH_ALEN];	/* ND source link layer address. */
					u8 tll[ETH_ALEN];	/* ND target link layer address. */
				} nd;
			};
		} ipv6;
	};
	struct {
		/* Connection tracking fields not packed above. */
		struct {
			__be16 src;	/* CT orig tuple tp src port. */
			__be16 dst;	/* CT orig tuple tp dst port. */
		} orig_tp;
		u32 mark;
		struct ovs_key_ct_labels labels;
	} ct;

};

struct ip_tunnel_key {
	__be64			tun_id;
	union {
		struct {
			__be32	src;
			__be32	dst;
		} ipv4;
		struct {
			struct in6_addr src;
			struct in6_addr dst;
		} ipv6;
	} u;
	__be16			tun_flags;
	u8			tos;		/* TOS for IPv4, TC for IPv6 */
	u8			ttl;		/* TTL for IPv4, HL for IPv6 */
	__be32                  label;          /* Flow Label for IPv6 */
	__be16			tp_src;
	__be16			tp_dst;
};

(https://blog.csdn.net/yuzhihui_no1/article/details/39481745)[https://blog.csdn.net/yuzhihui_no1/article/details/39481745]