DPDK flow_classify 源码阅读

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/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2017 Intel Corporation
 */

#include <stdint.h>
#include <inttypes.h>
#include <getopt.h>

#include <rte_eal.h>
#include <rte_ethdev.h>
#include <rte_cycles.h>
#include <rte_lcore.h>
#include <rte_mbuf.h>
#include <rte_flow.h>
#include <rte_flow_classify.h>
#include <rte_table_acl.h>

#define RX_RING_SIZE 1024
#define TX_RING_SIZE 1024

#define NUM_MBUFS 8191
#define MBUF_CACHE_SIZE 250
#define BURST_SIZE 32

#define MAX_NUM_CLASSIFY 30
#define FLOW_CLASSIFY_MAX_RULE_NUM 91
#define FLOW_CLASSIFY_MAX_PRIORITY 8
#define FLOW_CLASSIFIER_NAME_SIZE 64

#define COMMENT_LEAD_CHAR   ('#')
#define OPTION_RULE_IPV4    "rule_ipv4"
#define RTE_LOGTYPE_FLOW_CLASSIFY   RTE_LOGTYPE_USER3
#define flow_classify_log(format, ...)         RTE_LOG(ERR, FLOW_CLASSIFY, format, ##__VA_ARGS__)

#define uint32_t_to_char(ip, a, b, c, d) do {        *a = (unsigned char)(ip >> 24 & 0xff);        *b = (unsigned char)(ip >> 16 & 0xff);        *c = (unsigned char)(ip >> 8 & 0xff);        *d = (unsigned char)(ip & 0xff);    } while (0)

enum {
    CB_FLD_SRC_ADDR,
    CB_FLD_DST_ADDR,
    CB_FLD_SRC_PORT,
    CB_FLD_SRC_PORT_DLM,
    CB_FLD_SRC_PORT_MASK,
    CB_FLD_DST_PORT,
    CB_FLD_DST_PORT_DLM,
    CB_FLD_DST_PORT_MASK,
    CB_FLD_PROTO,
    CB_FLD_PRIORITY,
    CB_FLD_NUM,
};

static struct{
    const char *rule_ipv4_name;
} parm_config;
const char cb_port_delim[] = ":";

static const struct rte_eth_conf port_conf_default = {
    .rxmode = {
        .max_rx_pkt_len = ETHER_MAX_LEN,
        .ignore_offload_bitfield = 1,
    },
};

struct flow_classifier {
    struct rte_flow_classifier *cls;
};

struct flow_classifier_acl {
    struct flow_classifier cls;
} __rte_cache_aligned;

/* ACL field definitions for IPv4 5 tuple rule */

enum {
    PROTO_FIELD_IPV4, // 0
    SRC_FIELD_IPV4,   // 1
    DST_FIELD_IPV4,   // 2
    SRCP_FIELD_IPV4,  // 3
    DSTP_FIELD_IPV4,  // 4 
    NUM_FIELDS_IPV4   // 5
};

enum {
    PROTO_INPUT_IPV4,
    SRC_INPUT_IPV4,
    DST_INPUT_IPV4,
    SRCP_DESTP_INPUT_IPV4
};


/* 数据结构 rte_acl_field_def:ACL访问控制表的字段的定义
ACL规则中的每个字段都有一个关联定义。有五个,分别是:类型,大小,字段的索引(指示哪一个字段),输入索引(0-N)和(距离字段开始处的)偏移量。

*/
static struct rte_acl_field_def ipv4_defs[NUM_FIELDS_IPV4] = {
    /* first input field - always one byte long. */
    {
        .type = RTE_ACL_FIELD_TYPE_BITMASK,
        .size = sizeof(uint8_t),
        .field_index = PROTO_FIELD_IPV4,
        .input_index = PROTO_INPUT_IPV4,
        .offset = sizeof(struct ether_hdr) +
            offsetof(struct ipv4_hdr, next_proto_id),
    },
    /* next input field (IPv4 source address) - 4 consecutive bytes. */
    {
        /* rte_flow uses a bit mask for IPv4 addresses */
        .type = RTE_ACL_FIELD_TYPE_BITMASK,
        .size = sizeof(uint32_t),
        .field_index = SRC_FIELD_IPV4,
        .input_index = SRC_INPUT_IPV4,
        .offset = sizeof(struct ether_hdr) +
            offsetof(struct ipv4_hdr, src_addr),
    },
    /* next input field (IPv4 destination address) - 4 consecutive bytes. */
    {
        /* rte_flow uses a bit mask for IPv4 addresses */
        .type = RTE_ACL_FIELD_TYPE_BITMASK,
        .size = sizeof(uint32_t),
        .field_index = DST_FIELD_IPV4,
        .input_index = DST_INPUT_IPV4,
        .offset = sizeof(struct ether_hdr) +
            offsetof(struct ipv4_hdr, dst_addr),
    },
    /*
     * Next 2 fields (src & dst ports) form 4 consecutive bytes.
     * They share the same input index.
     */
    {
        /* rte_flow uses a bit mask for protocol ports */
        .type = RTE_ACL_FIELD_TYPE_BITMASK,
        .size = sizeof(uint16_t),
        .field_index = SRCP_FIELD_IPV4,
        .input_index = SRCP_DESTP_INPUT_IPV4,
        .offset = sizeof(struct ether_hdr) +
            sizeof(struct ipv4_hdr) +
            offsetof(struct tcp_hdr, src_port),
    },
    {
        /* rte_flow uses a bit mask for protocol ports */
        .type = RTE_ACL_FIELD_TYPE_BITMASK,
        .size = sizeof(uint16_t),
        .field_index = DSTP_FIELD_IPV4,
        .input_index = SRCP_DESTP_INPUT_IPV4,
        .offset = sizeof(struct ether_hdr) +
            sizeof(struct ipv4_hdr) +
            offsetof(struct tcp_hdr, dst_port),
    },
};

/* flow classify data */
static int num_classify_rules; // rules数组的下标
static struct rte_flow_classify_rule *rules[MAX_NUM_CLASSIFY]; // rules 数组
static struct rte_flow_classify_ipv4_5tuple_stats ntuple_stats;
static struct rte_flow_classify_stats classify_stats = {
        .stats = (void **)&ntuple_stats
};

/* parameters for rte_flow_classify_validate and
 * rte_flow_classify_table_entry_add functions
 */

static struct rte_flow_item  eth_item = { RTE_FLOW_ITEM_TYPE_ETH,
    0, 0, 0 };
static struct rte_flow_item  end_item = { RTE_FLOW_ITEM_TYPE_END,
    0, 0, 0 };

/* sample actions:
 * "actions count / end"
 */
struct rte_flow_query_count count = {
    .reset = 1,
    .hits_set = 1,
    .bytes_set = 1,
    .hits = 0,
    .bytes = 0,
};
static struct rte_flow_action count_action = { RTE_FLOW_ACTION_TYPE_COUNT,
    &count};
static struct rte_flow_action end_action = { RTE_FLOW_ACTION_TYPE_END, 0};
static struct rte_flow_action actions[2];

/* sample attributes */
static struct rte_flow_attr attr;

/* flow_classify.c: * Based on DPDK skeleton forwarding example. */

/*
 * Initializes a given port using global settings and with the RX buffers
 * coming from the mbuf_pool passed as a parameter.
 */
static inline int
port_init(uint8_t port, struct rte_mempool *mbuf_pool)
{
    struct rte_eth_conf port_conf = port_conf_default;
    struct ether_addr addr;
    const uint16_t rx_rings = 1, tx_rings = 1;
    int retval;
    uint16_t q;
    struct rte_eth_dev_info dev_info;
    struct rte_eth_txconf txconf;

    if (!rte_eth_dev_is_valid_port(port))
        return -1;

    rte_eth_dev_info_get(port, &dev_info);
    if (dev_info.tx_offload_capa & DEV_TX_OFFLOAD_MBUF_FAST_FREE)
        port_conf.txmode.offloads |=
            DEV_TX_OFFLOAD_MBUF_FAST_FREE;

    /* Configure the Ethernet device. */
    retval = rte_eth_dev_configure(port, rx_rings, tx_rings, &port_conf);
    if (retval != 0)
        return retval;

    /* Allocate and set up 1 RX queue per Ethernet port. */
    for (q = 0; q < rx_rings; q++) {
        retval = rte_eth_rx_queue_setup(port, q, RX_RING_SIZE,
                rte_eth_dev_socket_id(port), NULL, mbuf_pool);
        if (retval < 0)
            return retval;
    }

    txconf = dev_info.default_txconf;
    txconf.txq_flags = ETH_TXQ_FLAGS_IGNORE;
    txconf.offloads = port_conf.txmode.offloads;
    /* Allocate and set up 1 TX queue per Ethernet port. */
    for (q = 0; q < tx_rings; q++) {
        retval = rte_eth_tx_queue_setup(port, q, TX_RING_SIZE,
                rte_eth_dev_socket_id(port), &txconf);
        if (retval < 0)
            return retval;
    }

    /* Start the Ethernet port. */
    retval = rte_eth_dev_start(port);
    if (retval < 0)
        return retval;

    /* Display the port MAC address. */
    rte_eth_macaddr_get(port, &addr);
    printf("Port %u MAC: %02" PRIx8 " %02" PRIx8 " %02" PRIx8
               " %02" PRIx8 " %02" PRIx8 " %02" PRIx8 "
",
            port,
            addr.addr_bytes[0], addr.addr_bytes[1],
            addr.addr_bytes[2], addr.addr_bytes[3],
            addr.addr_bytes[4], addr.addr_bytes[5]);

    /* Enable RX in promiscuous mode for the Ethernet device. */
    rte_eth_promiscuous_enable(port);

    return 0;
}

/*
 * The lcore main. This is the main thread that does the work, reading from
 * an input port classifying the packets and writing to an output port.
 */
static __attribute__((noreturn)) void
lcore_main(struct flow_classifier *cls_app)
{
    uint16_t port;
    int ret;
    int i = 0;

    ret = rte_flow_classify_table_entry_delete(cls_app->cls,
            rules[7]);
    if (ret)
        printf("table_entry_delete failed [7] %d

", ret);
    else
        printf("table_entry_delete succeeded [7]

");

    /*
     * Check that the port is on the same NUMA node as the polling thread
     * for best performance.
     */
    RTE_ETH_FOREACH_DEV(port)
        if (rte_eth_dev_socket_id(port) > 0 &&
            rte_eth_dev_socket_id(port) != (int)rte_socket_id()) {
            printf("

");
            printf("WARNING: port %u is on remote NUMA node
",
                   port);
            printf("to polling thread.
");
            printf("Performance will not be optimal.
");
        }
    printf("
Core %u forwarding packets. ", rte_lcore_id());
    printf("[Ctrl+C to quit]
");

    /* Run until the application is quit or killed. */
    for (;;) {
        /*
         * Receive packets on a port, **classify them** and forward them
         * on the paired port.
         * The mapping is 0 -> 1, 1 -> 0, 2 -> 3, 3 -> 2, etc.
         */
        RTE_ETH_FOREACH_DEV(port) {
            /* Get burst of RX packets, from first port of pair. */
            struct rte_mbuf *bufs[BURST_SIZE];
            const uint16_t nb_rx = rte_eth_rx_burst(port, 0,
                    bufs, BURST_SIZE); // 收包

            if (unlikely(nb_rx == 0))
                continue;

            for (i = 0; i < MAX_NUM_CLASSIFY; i++) {
                if (rules[i]) { // 在classifier中查询特定的规则
                // 收包之后,将感兴趣的流放到
                    ret = rte_flow_classifier_query(
                        cls_app->cls, // 流分类器句柄
                        // 要处理的数据包的 mbuf
                        // 数据包数量
                        // 规则
                        bufs, nb_rx, rules[i], 
                        &classify_stats);
                    if (ret) // 返回 0 代表分类成功
                        printf(
                            "rule [%d] query failed ret [%d]

",
                            i, ret);
                    else {
                        printf(
                        "rule[%d] count=%"PRIu64"
",
                        i, ntuple_stats.counter1);

                        printf("proto = %d
",
                        ntuple_stats.ipv4_5tuple.proto);
                    }
                }
            }

            /* Send burst of TX packets, to second port of pair. */
            const uint16_t nb_tx = rte_eth_tx_burst(port ^ 1, 0,
                    bufs, nb_rx);

            /* Free any unsent packets. */
            if (unlikely(nb_tx < nb_rx)) {
                uint16_t buf;

                for (buf = nb_tx; buf < nb_rx; buf++)
                    rte_pktmbuf_free(bufs[buf]);
            }
        }
    }
}

/*
 * Parse IPv4 5 tuple rules file, ipv4_rules_file.txt.
 * Expected format:
 * <src_ipv4_addr>'/'<masklen> <space>  * <dst_ipv4_addr>'/'<masklen> <space>  * <src_port> <space> ":" <src_port_mask> <space>  * <dst_port> <space> ":" <dst_port_mask> <space>  * <proto>'/'<proto_mask> <space>  * <priority>
 */

static int
get_cb_field(char **in, uint32_t *fd, int base, unsigned long lim,
        char dlm)
{
    unsigned long val;
    char *end;

    errno = 0;
    val = strtoul(*in, &end, base);
    if (errno != 0 || end[0] != dlm || val > lim)
        return -EINVAL;
    *fd = (uint32_t)val;
    *in = end + 1;
    return 0;
}

static int
parse_ipv4_net(char *in, uint32_t *addr, uint32_t *mask_len)
{
    uint32_t a, b, c, d, m;

    if (get_cb_field(&in, &a, 0, UINT8_MAX, '.'))
        return -EINVAL;
    if (get_cb_field(&in, &b, 0, UINT8_MAX, '.'))
        return -EINVAL;
    if (get_cb_field(&in, &c, 0, UINT8_MAX, '.'))
        return -EINVAL;
    if (get_cb_field(&in, &d, 0, UINT8_MAX, '/'))
        return -EINVAL;
    if (get_cb_field(&in, &m, 0, sizeof(uint32_t) * CHAR_BIT, 0))
        return -EINVAL;

    addr[0] = IPv4(a, b, c, d);
    mask_len[0] = m;
    return 0;
}

static int
parse_ipv4_5tuple_rule(char *str, struct rte_eth_ntuple_filter *ntuple_filter)
{
    int i, ret;
    char *s, *sp, *in[CB_FLD_NUM];
    static const char *dlm = " 	
";
    int dim = CB_FLD_NUM;
    uint32_t temp;

    s = str;
    for (i = 0; i != dim; i++, s = NULL) {
        in[i] = strtok_r(s, dlm, &sp);
        if (in[i] == NULL)
            return -EINVAL;
    }

    ret = parse_ipv4_net(in[CB_FLD_SRC_ADDR],
            &ntuple_filter->src_ip,
            &ntuple_filter->src_ip_mask);
    if (ret != 0) {
        flow_classify_log("failed to read source address/mask: %s
",
            in[CB_FLD_SRC_ADDR]);
        return ret;
    }

    ret = parse_ipv4_net(in[CB_FLD_DST_ADDR],
            &ntuple_filter->dst_ip,
            &ntuple_filter->dst_ip_mask);
    if (ret != 0) {
        flow_classify_log("failed to read source address/mask: %s
",
            in[CB_FLD_DST_ADDR]);
        return ret;
    }

    if (get_cb_field(&in[CB_FLD_SRC_PORT], &temp, 0, UINT16_MAX, 0))
        return -EINVAL;
    ntuple_filter->src_port = (uint16_t)temp;

    if (strncmp(in[CB_FLD_SRC_PORT_DLM], cb_port_delim,
            sizeof(cb_port_delim)) != 0)
        return -EINVAL;

    if (get_cb_field(&in[CB_FLD_SRC_PORT_MASK], &temp, 0, UINT16_MAX, 0))
        return -EINVAL;
    ntuple_filter->src_port_mask = (uint16_t)temp;

    if (get_cb_field(&in[CB_FLD_DST_PORT], &temp, 0, UINT16_MAX, 0))
        return -EINVAL;
    ntuple_filter->dst_port = (uint16_t)temp;

    if (strncmp(in[CB_FLD_DST_PORT_DLM], cb_port_delim,
            sizeof(cb_port_delim)) != 0)
        return -EINVAL;

    if (get_cb_field(&in[CB_FLD_DST_PORT_MASK], &temp, 0, UINT16_MAX, 0))
        return -EINVAL;
    ntuple_filter->dst_port_mask = (uint16_t)temp;

    if (get_cb_field(&in[CB_FLD_PROTO], &temp, 0, UINT8_MAX, '/'))
        return -EINVAL;
    ntuple_filter->proto = (uint8_t)temp;

    if (get_cb_field(&in[CB_FLD_PROTO], &temp, 0, UINT8_MAX, 0))
        return -EINVAL;
    ntuple_filter->proto_mask = (uint8_t)temp;

    if (get_cb_field(&in[CB_FLD_PRIORITY], &temp, 0, UINT16_MAX, 0))
        return -EINVAL;
    ntuple_filter->priority = (uint16_t)temp;
    if (ntuple_filter->priority > FLOW_CLASSIFY_MAX_PRIORITY)
        ret = -EINVAL;

    return ret;
}

/* Bypass comment and empty lines */
static inline int
is_bypass_line(char *buff)
{
    int i = 0;

    /* comment line */
    if (buff[0] == COMMENT_LEAD_CHAR)
        return 1;
    /* empty line */
    while (buff[i] != '') {
        if (!isspace(buff[i]))
            return 0;
        i++;
    }
    return 1;
}

static uint32_t
convert_depth_to_bitmask(uint32_t depth_val)
{
    uint32_t bitmask = 0;
    int i, j;

    for (i = depth_val, j = 0; i > 0; i--, j++)
        bitmask |= (1 << (31 - j));
    return bitmask;
}

static int
add_classify_rule(struct rte_eth_ntuple_filter *ntuple_filter,
        struct flow_classifier *cls_app) // 一层封装
{
    int ret = -1;
    int key_found;
    struct rte_flow_error error;
    struct rte_flow_item_ipv4 ipv4_spec;
    struct rte_flow_item_ipv4 ipv4_mask;
    struct rte_flow_item ipv4_udp_item;
    struct rte_flow_item ipv4_tcp_item;
    struct rte_flow_item ipv4_sctp_item;
    struct rte_flow_item_udp udp_spec;
    struct rte_flow_item_udp udp_mask;
    struct rte_flow_item udp_item;
    struct rte_flow_item_tcp tcp_spec;
    struct rte_flow_item_tcp tcp_mask;
    struct rte_flow_item tcp_item;
    struct rte_flow_item_sctp sctp_spec;
    struct rte_flow_item_sctp sctp_mask;
    struct rte_flow_item sctp_item;
    struct rte_flow_item pattern_ipv4_5tuple[4];
    struct rte_flow_classify_rule *rule;
    uint8_t ipv4_proto;

    if (num_classify_rules >= MAX_NUM_CLASSIFY) {
        printf(
            "
INFO:  classify rule capacity %d reached
",
            num_classify_rules);
        return ret;
    }

    /* set up parameters for validate and add */
    memset(&ipv4_spec, 0, sizeof(ipv4_spec));
    ipv4_spec.hdr.next_proto_id = ntuple_filter->proto;
    ipv4_spec.hdr.src_addr = ntuple_filter->src_ip;
    ipv4_spec.hdr.dst_addr = ntuple_filter->dst_ip;
    ipv4_proto = ipv4_spec.hdr.next_proto_id;

    memset(&ipv4_mask, 0, sizeof(ipv4_mask));
    ipv4_mask.hdr.next_proto_id = ntuple_filter->proto_mask;
    ipv4_mask.hdr.src_addr = ntuple_filter->src_ip_mask;
    ipv4_mask.hdr.src_addr =
        convert_depth_to_bitmask(ipv4_mask.hdr.src_addr);
    ipv4_mask.hdr.dst_addr = ntuple_filter->dst_ip_mask;
    ipv4_mask.hdr.dst_addr =
        convert_depth_to_bitmask(ipv4_mask.hdr.dst_addr);

    switch (ipv4_proto) {
    case IPPROTO_UDP:
        ipv4_udp_item.type = RTE_FLOW_ITEM_TYPE_IPV4;
        ipv4_udp_item.spec = &ipv4_spec;
        ipv4_udp_item.mask = &ipv4_mask;
        ipv4_udp_item.last = NULL;

        udp_spec.hdr.src_port = ntuple_filter->src_port;
        udp_spec.hdr.dst_port = ntuple_filter->dst_port;
        udp_spec.hdr.dgram_len = 0;
        udp_spec.hdr.dgram_cksum = 0;

        udp_mask.hdr.src_port = ntuple_filter->src_port_mask;
        udp_mask.hdr.dst_port = ntuple_filter->dst_port_mask;
        udp_mask.hdr.dgram_len = 0;
        udp_mask.hdr.dgram_cksum = 0;

        udp_item.type = RTE_FLOW_ITEM_TYPE_UDP;
        udp_item.spec = &udp_spec;
        udp_item.mask = &udp_mask;
        udp_item.last = NULL;

        attr.priority = ntuple_filter->priority;
        pattern_ipv4_5tuple[1] = ipv4_udp_item;
        pattern_ipv4_5tuple[2] = udp_item;
        break;
    case IPPROTO_TCP:
        ipv4_tcp_item.type = RTE_FLOW_ITEM_TYPE_IPV4;
        ipv4_tcp_item.spec = &ipv4_spec;
        ipv4_tcp_item.mask = &ipv4_mask;
        ipv4_tcp_item.last = NULL;

        memset(&tcp_spec, 0, sizeof(tcp_spec));
        tcp_spec.hdr.src_port = ntuple_filter->src_port;
        tcp_spec.hdr.dst_port = ntuple_filter->dst_port;

        memset(&tcp_mask, 0, sizeof(tcp_mask));
        tcp_mask.hdr.src_port = ntuple_filter->src_port_mask;
        tcp_mask.hdr.dst_port = ntuple_filter->dst_port_mask;

        tcp_item.type = RTE_FLOW_ITEM_TYPE_TCP;
        tcp_item.spec = &tcp_spec;
        tcp_item.mask = &tcp_mask;
        tcp_item.last = NULL;

        attr.priority = ntuple_filter->priority;
        pattern_ipv4_5tuple[1] = ipv4_tcp_item;
        pattern_ipv4_5tuple[2] = tcp_item;
        break;
    case IPPROTO_SCTP:
        ipv4_sctp_item.type = RTE_FLOW_ITEM_TYPE_IPV4;
        ipv4_sctp_item.spec = &ipv4_spec;
        ipv4_sctp_item.mask = &ipv4_mask;
        ipv4_sctp_item.last = NULL;

        sctp_spec.hdr.src_port = ntuple_filter->src_port;
        sctp_spec.hdr.dst_port = ntuple_filter->dst_port;
        sctp_spec.hdr.cksum = 0;
        sctp_spec.hdr.tag = 0;

        sctp_mask.hdr.src_port = ntuple_filter->src_port_mask;
        sctp_mask.hdr.dst_port = ntuple_filter->dst_port_mask;
        sctp_mask.hdr.cksum = 0;
        sctp_mask.hdr.tag = 0;

        sctp_item.type = RTE_FLOW_ITEM_TYPE_SCTP;
        sctp_item.spec = &sctp_spec;
        sctp_item.mask = &sctp_mask;
        sctp_item.last = NULL;

        attr.priority = ntuple_filter->priority;
        pattern_ipv4_5tuple[1] = ipv4_sctp_item;
        pattern_ipv4_5tuple[2] = sctp_item;
        break;
    default:
        return ret;
    }

    attr.ingress = 1;
    pattern_ipv4_5tuple[0] = eth_item;
    pattern_ipv4_5tuple[3] = end_item;
    actions[0] = count_action;
    actions[1] = end_action;

    /* Validate and add rule */
    // 验证这条规则
    ret = rte_flow_classify_validate(cls_app->cls, &attr,
            pattern_ipv4_5tuple, actions, &error);
    if (ret) { // 成功时返回 0 
        printf("table entry validate failed ipv4_proto = %u
",
            ipv4_proto);
        return ret;
    }

    // 调用 rte_flow_classify_table_entry_add() 将规则添加到 rte_flow_classifier 对象中的table。
    /* 五个参数
        1. classifier的句柄
        2. 流规则属性
        3. 模式规范
        4. 关联的操作
        5. 如果规则已经存在则返回1,否则返回0。
        6. 仅在出错的情况下初始化这个结构。
    */
    rule = rte_flow_classify_table_entry_add(
            cls_app->cls, &attr, pattern_ipv4_5tuple,
            actions, &key_found, &error);
    if (rule == NULL) { // 成功时的有效句柄,否则为NULL
        printf("table entry add failed ipv4_proto = %u
",
            ipv4_proto);
        ret = -1;
        return ret;
    }

    rules[num_classify_rules] = rule;
    num_classify_rules++;
    return 0;
}

static int
add_rules(const char *rule_path, struct flow_classifier *cls_app) // 封装一层
{
    FILE *fh;
    char buff[LINE_MAX];
    unsigned int i = 0;
    unsigned int total_num = 0;
    struct rte_eth_ntuple_filter ntuple_filter; // 用于定义n-tuple过滤器条目
    int ret;

    fh = fopen(rule_path, "rb"); // 打开 ipv4_rules_file.txt
    if (fh == NULL)
        rte_exit(EXIT_FAILURE, "%s: fopen %s failed
", __func__,
            rule_path);

    ret = fseek(fh, 0, SEEK_SET);
    if (ret)
        rte_exit(EXIT_FAILURE, "%s: fseek %d failed
", __func__,
            ret);

    i = 0;
    while (fgets(buff, LINE_MAX, fh) != NULL) { // 读取一行内容
        i++;

        if (is_bypass_line(buff)) // 如果是注释行 or 空行就跳过
            continue;

        if (total_num >= FLOW_CLASSIFY_MAX_RULE_NUM - 1) { // 最大规则数量限制
            printf("
INFO: classify rule capacity %d reached
",
                total_num);
            break;
        }

        if (parse_ipv4_5tuple_rule(buff, &ntuple_filter) != 0) // 过规则的 parser 解析出 rule
            rte_exit(EXIT_FAILURE,
                "%s Line %u: parse rules error
",
                rule_path, i);

        if (add_classify_rule(&ntuple_filter, cls_app) != 0) // 添加这条规则到 ACL 中
            rte_exit(EXIT_FAILURE, "add rule error
");

        total_num++;
    }

    fclose(fh);
    return 0;
}

/* display usage */
static void
print_usage(const char *prgname)
{
    printf("%s usage:
", prgname);
    printf("[EAL options] --  --"OPTION_RULE_IPV4"=FILE: ");
    printf("specify the ipv4 rules file.
");
    printf("Each rule occupies one line in the file.
");
}

/* Parse the argument given in the command line of the application */
// 解析执行 flow_classify 的命令行参数
static int
parse_args(int argc, char **argv)
{
    int opt, ret;
    char **argvopt;
    int option_index;
    char *prgname = argv[0];
    static struct option lgopts[] = {
        {OPTION_RULE_IPV4, 1, 0, 0},
        {NULL, 0, 0, 0}
    };

    argvopt = argv;

    while ((opt = getopt_long(argc, argvopt, "",
                lgopts, &option_index)) != EOF) {

        switch (opt) {
        /* long options */
        case 0:
            if (!strncmp(lgopts[option_index].name,
                    OPTION_RULE_IPV4,
                    sizeof(OPTION_RULE_IPV4)))
                parm_config.rule_ipv4_name = optarg;
            break;
        default:
            print_usage(prgname);
            return -1;
        }
    }

    if (optind >= 0)
        argv[optind-1] = prgname;

    ret = optind-1;
    optind = 1; /* reset getopt lib */
    return ret;
}

/*
 * The main function, which does initialization and calls the lcore_main
 * function.
 */
int
main(int argc, char *argv[])
{
    struct rte_mempool *mbuf_pool;
    uint8_t nb_ports;
    uint16_t portid;
    int ret;
    int socket_id;

    // 以下可以在 dpdk api data struct 中查看
    struct rte_table_acl_params table_acl_params; // ACL 的参数
    struct rte_flow_classify_table_params cls_table_params; // ACL中 table 的参数
    struct flow_classifier *cls_app;  // 分流器
    struct rte_flow_classifier_params cls_params; // classifier 的参数
    uint32_t size;

    /* Initialize the Environment Abstraction Layer (EAL). */
    ret = rte_eal_init(argc, argv); // 初始化 EAL
    if (ret < 0)
        rte_exit(EXIT_FAILURE, "Error with EAL initialization
");

    argc -= ret;
    argv += ret;

    /* parse application arguments (after the EAL ones) */
    ret = parse_args(argc, argv); // 解析除了 EAL 之外(也就是flow_classify)的命令行参数
    if (ret < 0)
        rte_exit(EXIT_FAILURE, "Invalid flow_classify parameters
");

    /* Check that there is an even number of ports to send/receive on. */
    nb_ports = rte_eth_dev_count(); // 网口数目必须是偶数
    if (nb_ports < 2 || (nb_ports & 1))
        rte_exit(EXIT_FAILURE, "Error: number of ports must be even
");

    /* Creates a new mempool in memory to hold the mbufs. */
    // 创建mempool
    mbuf_pool = rte_pktmbuf_pool_create("MBUF_POOL", NUM_MBUFS * nb_ports,
        MBUF_CACHE_SIZE, 0, RTE_MBUF_DEFAULT_BUF_SIZE, rte_socket_id());

    if (mbuf_pool == NULL)
        rte_exit(EXIT_FAILURE, "Cannot create mbuf pool
");

    /* Initialize all ports. */
    RTE_ETH_FOREACH_DEV(portid) // 端口初始化
        if (port_init(portid, mbuf_pool) != 0)
            rte_exit(EXIT_FAILURE, "Cannot init port %"PRIu8 "
",
                    portid);

    if (rte_lcore_count() > 1) // 只需要一个逻辑核心
        printf("
WARNING: Too many lcores enabled. Only 1 used.
");

    socket_id = rte_eth_dev_socket_id(0); // 返回 0 号网口所在的NUMA socket id号

    /* Memory allocation */
    // 为分流器 cls_app 分配内存
    size = RTE_CACHE_LINE_ROUNDUP(sizeof(struct flow_classifier_acl));// 返回大于或等于宏定义参数的第一个缓存对齐值
    cls_app = rte_zmalloc(NULL, size, RTE_CACHE_LINE_SIZE); // DPDK的malloc:从调用该函数的核上的同一个NUMA socket的大页面区域分配堆内存。
                                                            // zmalloc 就是清零 与 calloc 相似
    /* rte_zmalloc 参数三个:
        1. 指示这块区域分配给怎样的object类型。用于debug用途。可以写NULL
        2. size (in bytes) to be allocated
        3. align
            if 0, 会返回一个适合任何类型变量的指针,就像 malloc
            否则,返回一个内存区域是 align 的对齐倍数,显然最小对齐是高速缓存行大小,宏:RTE_CACHE_LINE_SIZE
    */
    if (cls_app == NULL) // 分配内存失败
        rte_exit(EXIT_FAILURE, "Cannot allocate classifier memory
");

    // classifier 的参数 有两个: name 和 socket id
    cls_params.name = "flow_classifier";
    cls_params.socket_id = socket_id;

    // 调用 rte_flow_classifier_create() 函数来创建rte_flow_classifier对象。
    // 参数是 rte_flow_classifier_params 结构体指针
    cls_app->cls = rte_flow_classifier_create(&cls_params);
    if (cls_app->cls == NULL) { // 创建失败
        rte_free(cls_app);
        rte_exit(EXIT_FAILURE, "Cannot create classifier
");
    }

    /* initialise ACL table params */
    // 填写 ACL 的初始化参数
    // 四个字段:
    table_acl_params.name = "table_acl_ipv4_5tuple"; // 名字
    table_acl_params.n_rules = FLOW_CLASSIFY_MAX_RULE_NUM; // 表中最大ACL规则数量:91 
    table_acl_params.n_rule_fields = RTE_DIM(ipv4_defs); // (todo) 一条ACL规则中的字段数量
    memcpy(table_acl_params.field_format, ipv4_defs, sizeof(ipv4_defs)); // (todo) ACL rule的详细specification

    /* initialise table create params */
    // 填写 表 的创建参数
    // 三个字段:
    cls_table_params.ops = &rte_table_acl_ops; //(todo)Table operations (specific to each table type)
    cls_table_params.arg_create = &table_acl_params; // 传递给表的用于创建的参数 这里是ACL的初始化参数结构体的指针
    cls_table_params.type = RTE_FLOW_CLASSIFY_TABLE_ACL_IP4_5TUPLE; // (todo)table type 

    // rte_flow_classify_table_create() 在classifier对象中创建表。
    // 参数两个:1. 流分类器的指针 2. 表创建的参数
    ret = rte_flow_classify_table_create(cls_app->cls, &cls_table_params);
    if (ret) { // 返回值:成功时返回 0
        rte_flow_classifier_free(cls_app->cls);
        rte_free(cls_app);
        rte_exit(EXIT_FAILURE, "Failed to create classifier table
");
    }

    /* read file of IPv4 5 tuple rules and initialize parameters
     * for rte_flow_classify_validate and rte_flow_classify_table_entry_add
     * API's.
     */
    // 然后它读取ipv4_rules_file.txt文件,初始化rte_flow_classify_table_entry_add() API 的参数。此API将规则添加到ACL表。
    if (add_rules(parm_config.rule_ipv4_name, cls_app)) {
        rte_flow_classifier_free(cls_app->cls);
        rte_free(cls_app);
        rte_exit(EXIT_FAILURE, "Failed to add rules
");
    }

    /* Call lcore_main on the master core only. */ // todo
    lcore_main(cls_app);

    return 0;
}

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