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struct  {    struct ovs_list list_node; 

    //匹配项，支持standard和OXM两种类型    struct match match;    //流表优先级    int priority;    //添加流表时这两项为0    ovs_be64 cookie;         /* Cookie bits to match. */    ovs_be64 cookie_mask;    /* 1-bit in each 'cookie' bit to match. */    ovs_be64 new_cookie;     /* New cookie to install or UINT64_MAX. */    bool modify_cookie;      /* Set cookie of existing flow to 'new_cookie'? */    //流表的table id，只有删除的时候不需要指定    uint8_t table_id;    //操作命令，是添加、删除还是修改    uint16_t command;    //空闲超时时间，即流表没有报文之后多长时间销毁流表    uint16_t idle_timeout;    //硬超时时间，从建立起多长时间销毁流表，不论有木有报文    uint16_t hard_timeout;    uint32_t buffer_id;    //出端口    ofp_port_t out_port;    uint32_t out_group;    //一些操作标识，比如要不要统计等等    enum ofputil_flow_mod_flags flags;    uint16_t importance;     /* Eviction precedence. */    //操作    struct ofpact *ofpacts;  /* Series of "struct ofpact"s. */    size_t ofpacts_len;      /* Length of ofpacts, in bytes. */};

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struct ofproto_flow_mod {    //rculist链表，里面存储了match项，和上面的match项还是有差别的    //上面的match结构主要是flow和mask两个结构    //rule里面的是minimatch，里面包含了上面的两个flow，并且还有flowmap    //rule的其他信息基本上是从上面拷贝过来的    struct rule *temp_rule;    struct rule_criteria criteria;    //和actions相关的，不太明白    struct cls_conjunction *conjs;    size_t n_conjs;

    //以下两条直接从上面数据结构拷贝    uint16_t command;    bool modify_cookie;    //允许添加流表    bool modify_may_add_flow;    //取自上面的flags，是否保持统计，false表示重新统计    bool modify_keep_counts;    enum nx_flow_update_event event;

    ovs_version_t version;

    bool learn_adds_rule;               /* Learn execution adds a rule. */    struct rule_collection old_rules;   /* Affected rules. */    struct rule_collection new_rules;   /* Replacement rules. */};

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struct rule {    //包含自己的ofproto    struct ofproto *const ofproto; /* The ofproto that contains this rule. */    const struct cls_rule cr;      /* In owning ofproto's classifier. */    //流表中看到的table_id    const uint8_t table_id;        /* Index in ofproto's 'tables' array. */

    //流表状态，包括初始化、插入和删除    enum rule_state state;

    //用于释放的引用计数    struct ovs_refcount ref_count;

    const ovs_be64 flow_cookie; /* Immutable once rule is constructed. */    struct hindex_node cookie_node OVS_GUARDED_BY(ofproto_mutex);

    enum ofputil_flow_mod_flags flags OVS_GUARDED;

    //对应上面的两个超时    uint16_t hard_timeout OVS_GUARDED; /* In seconds from ->modified. */    uint16_t idle_timeout OVS_GUARDED; /* In seconds from ->used. */

    /* Eviction precedence. */    const uint16_t importance;

    uint8_t removed_reason;

    struct eviction_group *eviction_group OVS_GUARDED_BY(ofproto_mutex);    struct heap_node evg_node OVS_GUARDED_BY(ofproto_mutex);

    //action操作    const struct rule_actions * const actions;

    /* In owning meter's 'rules' list.  An empty list if there is no meter. */    struct ovs_list meter_list_node OVS_GUARDED_BY(ofproto_mutex);

    enum nx_flow_monitor_flags monitor_flags OVS_GUARDED_BY(ofproto_mutex);    uint64_t add_seqno OVS_GUARDED_BY(ofproto_mutex);    uint64_t modify_seqno OVS_GUARDED_BY(ofproto_mutex);

    struct ovs_list expirable OVS_GUARDED_BY(ofproto_mutex);

    long long int created OVS_GUARDED; /* Creation time. */

    long long int modified OVS_GUARDED; /* Time of last modification. */};

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struct ofproto {    struct hmap_node hmap_node; /* In global 'all_ofprotos' hmap. */    const struct ofproto_class *ofproto_class;    char *type;                 /* Datapath type. */    char *name;                 /* Datapath name. */

    /* Settings. */    uint64_t fallback_dpid;     /* Datapath ID if no better choice found. */    uint64_t datapath_id;       /* Datapath ID. */    bool forward_bpdu;          /* Option to allow forwarding of BPDU frames                                 * when NORMAL action is invoked. */    char *mfr_desc;             /* Manufacturer (NULL for default). */    char *hw_desc;              /* Hardware (NULL for default). */    char *sw_desc;              /* Software version (NULL for default). */    char *serial_desc;          /* Serial number (NULL for default). */    char *dp_desc;              /* Datapath description (NULL for default). */    enum ofputil_frag_handling frag_handling;

    /* Datapath. */    struct hmap ports;          /* Contains "struct ofport"s. */    struct shash port_by_name;    struct simap ofp_requests;  /* OpenFlow port number requests. */    uint16_t alloc_port_no;     /* Last allocated OpenFlow port number. */    uint16_t max_ports;         /* Max possible OpenFlow port num, plus one. */    struct hmap ofport_usage;   /* Map ofport to last used time. */    uint64_t change_seq;        /* Change sequence for netdev status. */

    /* Flow tables. */    long long int eviction_group_timer; /* For rate limited reheapification. */    struct oftable *tables;    int n_tables;    ovs_version_t tables_version;  /* Controls which rules are visible to                                    * table lookups. */

    /* Rules indexed on their cookie values, in all flow tables. */    struct hindex cookies OVS_GUARDED_BY(ofproto_mutex);    struct hmap learned_cookies OVS_GUARDED_BY(ofproto_mutex);

    /* List of expirable flows, in all flow tables. */    struct ovs_list expirable OVS_GUARDED_BY(ofproto_mutex);

    /* Meter table.     * OpenFlow meters start at 1.  To avoid confusion we leave the first     * pointer in the array un-used, and index directly with the OpenFlow     * meter_id. */    struct ofputil_meter_features meter_features;    struct meter **meters; /* 'meter_features.max_meter' + 1 pointers. */

    /* OpenFlow connections. */    struct connmgr *connmgr;

    int min_mtu;                    /* Current MTU of non-internal ports. */

    /* Groups. */    struct cmap groups;               /* Contains "struct ofgroup"s. */    uint32_t n_groups[4] OVS_GUARDED; /* # of existing groups of each type. */    struct ofputil_group_features ogf;

    /* Tunnel TLV mapping table. */    OVSRCU_TYPE(struct tun_table *) metadata_tab;

    /* Variable length mf_field mapping. Stores all configured variable length     * meta-flow fields (struct mf_field) in a switch. */    struct vl_mff_map vl_mff_map;};

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static booldpcls_lookup(struct dpcls *cls, const struct netdev_flow_key keys[],            struct dpcls_rule **rules, const size_t cnt,            int *num_lookups_p){    typedef uint32_t map_type;

    struct dpcls_subtable *subtable;

    //keys_map所有位都置1    map_type keys_map = TYPE_MAXIMUM(map_type); /* Set all bits. */    map_type found_map;    uint32_t hashes[MAP_BITS];    const struct cmap_node *nodes[MAP_BITS];

    //清除多余的位，只记录跟报文一样多的位    if (cnt != MAP_BITS) {        keys_map >>= MAP_BITS - cnt; /* Clear extra bits. */    }    memset(rules, 0, cnt * sizeof *rules);

    int lookups_match = 0, subtable_pos = 1;

    //dpcls是由众多的subtables组成，当新的规则插入时，子表根据情况动态创建。    //每个子表都是根据掩码来区分的，我们通过key和子表的掩码进行计算，    //找到匹配的表项，因为不会重复，所以只要找到即可停止    //以下就是循环所有子表进行查找    PVECTOR_FOR_EACH (subtable, &cls->subtables) {        int i;

        //这个循环是找到keys_map是1的最低位是多少，一开始的时候肯定全是1，就是从0开始        //然后根据报文的key和mask计算出hash存储起来，继续下一个1的位        //直到计算出所有报文hash值，下面会去匹配表项的        //hash值的计算可以通过cpu加速，需要cpu支持，并且编译时配置"-msse4.2"        ULLONG_FOR_EACH_1(i, keys_map) {            hashes[i] = netdev_flow_key_hash_in_mask(&keys[i],                        &subtable->mask);        }        //从子表中进行hash值的匹配，将匹配到node的报文的bit置1到found_map        found_map = cmap_find_batch(&subtable->rules, keys_map, hashes, nodes);        //在找到匹配node的报文的冲突hash链中继续详细匹配报文        ULLONG_FOR_EACH_1(i, found_map) {            struct dpcls_rule *rule;            //冲突链中继续检测key值是否匹配            CMAP_NODE_FOR_EACH (rule, cmap_node, nodes[i]) {                if (OVS_LIKELY(dpcls_rule_matches_key(rule, &keys[i]))) {                    //找到匹配的规则，则记录一下，后面会用到                    rules[i] = rule;                    subtable->hit_cnt++;                    lookups_match += subtable_pos;                    goto next;                }            }            //不匹配则将该位设置为0            ULLONG_SET0(found_map, i);  /* Did not match. */next:            ;                     /* Keep Sparse happy. */        }        //清除已经匹配流表的位        keys_map &= ~found_map;             /* Clear the found rules. */        if (!keys_map) {            if (num_lookups_p) {                *num_lookups_p = lookups_match;            }            return true;              /* All found. */        }        subtable_pos++;    }    if (num_lookups_p) {        *num_lookups_p = lookups_match;    }    return false;                     /* Some misses. */}