OVS中的key解析

Posted 2021-01-14 xidongyu

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]