dpdk-icmp应答的实现(附:网卡没有ipv4地址的解决)

目标

ping <网卡eth0的ip地址>,可以ping通。

基础:arp的实现

步骤

在arp.c的基础上:

:arrow_down: 宏

#define ENABLE_ICMP

:arrow_down: main中,与udpif (iphdr->next_proto_id = = IPPROTO_UDP)并列(因为icmp协议和udp并列,同属于传输层。)

#ifdef ENABLE_ICMP

if (iphdr->next_proto_id == IPPROTO_ICMP) {
    printf("[recv][icmp]");
    struct rte_icmp_hdr *icmphdr = (struct rte_icmp_hdr *)(iphdr + 1);
    // 在此只实现echo请求报文的回复,类型是08(RTE_IP_ICMP_ECHO_REQUEST)
    if (icmphdr->icmp_type == RTE_IP_ICMP_ECHO_REQUEST) {
        printf("[request]\n");
        struct rte_mbuf *txbuf = jr_send_icmp(
            mbuf_pool, ehdr->s_addr.addr_bytes, 
            iphdr->dst_addr, iphdr->src_addr, 
            icmphdr->icmp_ident, icmphdr->icmp_seq_nb
        );

        rte_eth_tx_burst(gDpdkPortId, 0, &txbuf, 1);// 真正的发送操作,第四个参数:发一个包,第二个参数:使用0号队列发送
        rte_pktmbuf_free(txbuf);                        

    }
    rte_pktmbuf_free(mbufs[i]);
}
#endif

:arrow_down: 编码函数

static int jr_encode_icmp_pkt(uint8_t *msg, uint8_t *dst_mac, uint32_t sip, uint32_t dip, uint16_t ident, uint16_t seqnb) {

    // eth
    struct rte_ether_hdr *eth = (struct rte_ether_hdr *)msg;
    rte_memcpy(eth->s_addr.addr_bytes, gSrcMac, RTE_ETHER_ADDR_LEN);
    rte_memcpy(eth->d_addr.addr_bytes, dst_mac, RTE_ETHER_ADDR_LEN);
    eth->ether_type = htons(RTE_ETHER_TYPE_IPV4);

    // ip
    struct rte_ipv4_hdr *ip = (struct rte_ipv4_hdr *)(msg + sizeof(struct rte_ether_hdr));
    ip->version_ihl = 0x45;
    ip->type_of_service = 0;
        //改
    ip->total_length = htons(sizeof(struct rte_ipv4_hdr) + sizeof(struct rte_icmp_hdr)); 
    ip->packet_id = 0;
    ip->fragment_offset = 0;
    ip->time_to_live = 64;
        //改
    ip->next_proto_id = IPPROTO_ICMP;
    ip->src_addr = sip;
    ip->dst_addr = dip;
    ip->hdr_checksum = 0; //不是废话
    ip->hdr_checksum = rte_ipv4_cksum(ip);

    // icmp
        //不改
    struct rte_icmp_hdr *icmp = (struct rte_icmp_hdr *)(msg + sizeof(struct rte_ether_hdr) + sizeof(struct rte_ipv4_hdr));
    icmp->icmp_type = RTE_IP_ICMP_ECHO_REPLY;
    icmp->icmp_code = 0;
    icmp->icmp_ident = ident;
    icmp->icmp_seq_nb = seqnb;

    icmp->icmp_cksum = 0; //不是废话
    icmp->icmp_cksum = jr_checksum(icmp, sizeof(struct rte_icmp_hdr));

    //调试
    struct in_addr addr;
    addr.s_addr = sip;
    printf("\n[send][icmp协议]src: %s, ", inet_ntoa(addr));

    addr.s_addr = dip;
    printf("dst: %s\n\n", inet_ntoa(addr));

    return 0;

}

:arrow_down: 在内存池中分配空间并且调用“编码函数”往新空间中写数据流的函数

注意total_len的功能。如果设置短了,那么wireshark抓到的包就短一截,即使你在编码函数中各字段设置的好好的。

static struct rte_mbuf * jr_send_icmp(struct rte_mempool *mbuf_pool, uint8_t *dst_mac, 
    uint32_t sip, uint32_t dip, uint16_t ident, uint16_t seqnb) {

    const unsigned total_len = sizeof(struct rte_ether_hdr) + sizeof(struct rte_ipv4_hdr) +sizeof(struct rte_icmp_hdr); //mbuf怎么用呢?先要知道从mempool中拿多长的一段(取多少数据)
    struct rte_mbuf *mbuf = rte_pktmbuf_alloc(mbuf_pool); 
    if (!mbuf) {
        rte_exit(EXIT_FAILURE, "rte_pktmbuf_alloc出错\n");
    }

    mbuf->pkt_len = total_len;
    mbuf->data_len = total_len; 

    uint8_t *pktdata = rte_pktmbuf_mtod(mbuf, uint8_t*); 

    jr_encode_icmp_pkt(pktdata, dst_mac, sip, dip, ident, seqnb); 
    return mbuf;
}

:arrow_down: 求checksum的函数。来自rfc。

为什么要自己实现,因为没有现成的。(用udp那个是不对的)

static uint16_t jr_checksum(uint16_t *addr, int count)
{
    register long sum = 0;
    while (count > 1) {
        sum += *(unsigned short * )addr++;
        count -= 2;
    }

    if (count > 0) {
        sum +=  *(unsigned char *)addr;
    }

    while (sum >> 16) {
        sum = (sum & 0xffff) + (sum >> 16);
    }
    return ~sum;
}

(完整代码放在本文最后,因为它太长了。)

注意事项

  1. 编写顺序:先框架,填字段,发现有需要从接收报文中拿到的数据,再去补齐参数。也就是:函数名-函数体-函数参数

  2. 特别要清楚检查包的长度

附:网卡没有ipv4地址的解决

今天是上学开工第一天,上来遇到桥接网卡没有ipv4地址的问题。硬控俩小时后,据说是vmware 17的bug。但是我上周在家就没问题。看到有人说他也这样。经过我的多方调查,有以下两个解决办法:

  • plan1:准备一根网线,一块扩展坞。

  • plan2:装vm16。

我选plan2,发现装了17就不能再装16。如何卸载vm17,请看这篇。 安装完vm16后,打开原来的虚拟机,显示有错误,点升级,写有严重的错误。去翻日志,写C:\Users\<我的用户名>\AppData\Roaming\VMware\preferences.ini不存在,去看了,存在啊。最后把虚拟机的.vmx文件和.vmdk文件中的版本号从11改为了16,终于能打开了。但是还是没有ipv4地址。但ipv6地址都是fe80的私有地址,我想到了可能是vmnet0的自动桥接自动得有错误。所以菜单编辑-虚拟网络编辑器-管理员权限-改成物理机网卡。重启虚拟机网络服务(sudo service networking restart),发现就有ipv4了。

太长不看版:卸掉17,安装16,改虚拟机配置文件中的版本号,打开虚拟机,自动桥接手动选择一下网卡,重启网络服务,即可。

由于换了版本,eth1的ip地址变为192.168.80.128,共享文件夹和si都只把路径改成新ip就可以直接访问了。

// 新的eth0信息
$ ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:0c:29:14:56:cf  
          inet addr:192.168.43.110  Bcast:192.168.43.255  Mask:255.255.255.0

中午回来热点断了自动连上校园网后,又来分配ipv6公网地址。把热点连上restart后ipv4又回来了。难道校园网只能分配ipv6吗?那么前文提到的plan 1到底管不管用呢 ,好心人v我一根网线,且听下回分解。

结果

icmp应答的完整代码

#include <rte_eal.h>
#include <rte_ethdev.h>
#include <rte_mbuf.h>
#include <arpa/inet.h>
#include <stdio.h>

#define ENABLE_SEND
#define ENABLE_ARP
#define ENABLE_ICMP


// 内存池大小,4096-1的含义是超过了4K就放别处
#define NUM_MBUFS (4096-1)

#define BURST_SIZE 32

#ifdef ENABLE_SEND

#define MAKE_IPV4_ADDR(a, b, c, d) (a + (b<<8) + (c<<16) + (d<<24))
static uint32_t gLocalIp = MAKE_IPV4_ADDR(192, 168, 43, 110);

//这样写不好,但比较清楚,所以暂且用全局变量
static uint32_t gSrcIp;  //形如192.168.3.19,是32位
static uint32_t gDstIp;

static uint8_t gSrcMac[RTE_ETHER_ADDR_LEN]; // 形如08-f4-58-1c-43-20,长度为6的char型数组
static uint8_t gDstMac[RTE_ETHER_ADDR_LEN]; 

static uint16_t gSrcPort; //端口号是16位的
static uint16_t gDstPort;

#endif

int gDpdkPortId = 0;

static const struct rte_eth_conf port_conf_default = {
    .rxmode = {.max_rx_pkt_len = RTE_ETHER_MAX_LEN }
};

// 设置网口接收数据,关联网口和dpdk程序
static void jr_init_port(struct rte_mempool *mbuf_pool) {

    // 1. 检测端口是否可用 (此处要运行dpdk的setup.sh,绑定端口)
    uint16_t nb_sys_ports= rte_eth_dev_count_avail(); //
    if (nb_sys_ports == 0) {
        rte_exit(EXIT_FAILURE, "没找到支持的eth端口\n");
    }

    // 获取 eth0 原生信息,方便后面用
    struct rte_eth_dev_info dev_info;
    rte_eth_dev_info_get(gDpdkPortId, &dev_info); 

    const int num_rx_queues = 1;//最大可用8,在此用1
    const int num_tx_queues = 1;//最大可用8,在此不用,也就是没有发送数据包的中断。因为本文件是recv,只接收不发送
    struct rte_eth_conf port_conf = port_conf_default;
    rte_eth_dev_configure(gDpdkPortId, num_rx_queues, num_tx_queues, &port_conf);


    //启动rx队列
    if (rte_eth_rx_queue_setup(gDpdkPortId, 0 , 1024, //0号接收队列共能囤积128条数据 //为什么改为1024:跟tx对应
        rte_eth_dev_socket_id(gDpdkPortId),NULL, mbuf_pool) < 0) {

        rte_exit(EXIT_FAILURE, "不能启动RX队列\n");

    }



#ifdef ENABLE_SEND
    //启动tx队列
    struct rte_eth_txconf txq_conf = dev_info.default_txconf;
    txq_conf.offloads = port_conf.rxmode.offloads;
    if (rte_eth_tx_queue_setup(gDpdkPortId, 0 , 1024, //0号队列共能囤积128条数据//为什么改为1024:Invalid value for nb_tx_desc(=128), should be: <= 4096, >= 512, and a product of 1
        rte_eth_dev_socket_id(gDpdkPortId),&txq_conf) < 0) {

        rte_exit(EXIT_FAILURE, "不能启动TX队列\n");

    }
#endif

    // 启动
    if (rte_eth_dev_start(gDpdkPortId) < 0 ) {
        rte_exit(EXIT_FAILURE, "无法启动\n");
    }

    rte_eth_promiscuous_enable(gDpdkPortId);

}


static uint16_t jr_checksum(uint16_t *addr, int count)
{
    register long sum = 0;
    while (count > 1) {
        sum += *(unsigned short * )addr++;
        count -= 2;
    }

    if (count > 0) {
        sum +=  *(unsigned char *)addr;
    }

    while (sum >> 16) {
        sum = (sum & 0xffff) + (sum >> 16);
    }
    return ~sum;
}


#ifdef ENABLE_ICMP

static int jr_encode_icmp_pkt(uint8_t *msg, uint8_t *dst_mac, uint32_t sip, uint32_t dip, uint16_t ident, uint16_t seqnb) {

    // eth
    struct rte_ether_hdr *eth = (struct rte_ether_hdr *)msg;
    rte_memcpy(eth->s_addr.addr_bytes, gSrcMac, RTE_ETHER_ADDR_LEN);
    rte_memcpy(eth->d_addr.addr_bytes, dst_mac, RTE_ETHER_ADDR_LEN);
    eth->ether_type = htons(RTE_ETHER_TYPE_IPV4);

    // ip
    struct rte_ipv4_hdr *ip = (struct rte_ipv4_hdr *)(msg + sizeof(struct rte_ether_hdr));
    ip->version_ihl = 0x45;
    ip->type_of_service = 0;
        //改
    ip->total_length = htons(sizeof(struct rte_ipv4_hdr) + sizeof(struct rte_icmp_hdr)); 
    ip->packet_id = 0;
    ip->fragment_offset = 0;
    ip->time_to_live = 64;
        //改
    ip->next_proto_id = IPPROTO_ICMP;
    ip->src_addr = sip;
    ip->dst_addr = dip;
    ip->hdr_checksum = 0; //不是废话
    ip->hdr_checksum = rte_ipv4_cksum(ip);

    // icmp
        //不改
    struct rte_icmp_hdr *icmp = (struct rte_icmp_hdr *)(msg + sizeof(struct rte_ether_hdr) + sizeof(struct rte_ipv4_hdr));
    icmp->icmp_type = RTE_IP_ICMP_ECHO_REPLY;
    icmp->icmp_code = 0;
    icmp->icmp_ident = ident;
    icmp->icmp_seq_nb = seqnb;

    icmp->icmp_cksum = 0; //不是废话
    icmp->icmp_cksum = jr_checksum(icmp, sizeof(struct rte_icmp_hdr));

    //调试
    struct in_addr addr;
    addr.s_addr = sip;
    printf("\n[send][icmp协议]src: %s, ", inet_ntoa(addr));

    addr.s_addr = dip;
    printf("dst: %s\n\n", inet_ntoa(addr));

    return 0;

}


static struct rte_mbuf * jr_send_icmp(struct rte_mempool *mbuf_pool, uint8_t *dst_mac, 
    uint32_t sip, uint32_t dip, uint16_t ident, uint16_t seqnb) {

    const unsigned total_len = sizeof(struct rte_ether_hdr) + sizeof(struct rte_ipv4_hdr) +sizeof(struct rte_icmp_hdr); //mbuf怎么用呢?先要知道从mempool中拿多长的一段(取多少数据)
    struct rte_mbuf *mbuf = rte_pktmbuf_alloc(mbuf_pool); 
    if (!mbuf) {
        rte_exit(EXIT_FAILURE, "rte_pktmbuf_alloc出错\n");
    }

    mbuf->pkt_len = total_len;
    mbuf->data_len = total_len; 

    uint8_t *pktdata = rte_pktmbuf_mtod(mbuf, uint8_t*); 

    jr_encode_icmp_pkt(pktdata, dst_mac, sip, dip, ident, seqnb); 
    return mbuf;
}

#endif


#ifdef ENABLE_ARP

static int jr_encode_arp_pkt(uint8_t *msg, uint8_t *dst_mac, uint32_t sip, uint32_t dip) {

    // 第一步 ethhdr
    struct rte_ether_hdr *eth = (struct rte_ether_hdr *)msg;
    rte_memcpy(eth->s_addr.addr_bytes, gSrcMac, RTE_ETHER_ADDR_LEN);
    rte_memcpy(eth->d_addr.addr_bytes, gDstMac, RTE_ETHER_ADDR_LEN);
    eth->ether_type = htons(RTE_ETHER_TYPE_ARP);// 复制时要改类型

    // 第二步 arp
    struct rte_arp_hdr *arp = (struct rte_arp_hdr*)(eth + 1);
    arp->arp_hardware = htons(1);
    arp->arp_protocol = htons(RTE_ETHER_TYPE_IPV4);
    arp->arp_hlen = RTE_ETHER_ADDR_LEN;
    arp->arp_plen =sizeof(uint32_t);
    arp->arp_opcode = htons(2);
    rte_memcpy(arp->arp_data.arp_sha.addr_bytes, gSrcMac, RTE_ETHER_ADDR_LEN);
    rte_memcpy(arp->arp_data.arp_tha.addr_bytes,dst_mac, RTE_ETHER_ADDR_LEN);
    arp->arp_data.arp_sip= sip;
    arp->arp_data.arp_tip=dip;
    return 0;
}

static struct rte_mbuf * jr_arp_send(struct rte_mempool *mbuf_pool, uint8_t *dst_mac, uint32_t sip, uint32_t dip) {
    const unsigned total_len = sizeof(struct rte_ether_hdr) + sizeof(struct rte_arp_hdr); //mbuf怎么用呢?先要知道从mempool中拿多长的一段(取多少数据)
    struct rte_mbuf *mbuf = rte_pktmbuf_alloc(mbuf_pool); 
    if (!mbuf) {
        rte_exit(EXIT_FAILURE, "rte_pktmbuf_alloc出错\n");
    }

    mbuf->pkt_len = total_len;
    mbuf->data_len = total_len; //思考:这两个为什么设成一样的

    uint8_t *pktdata = rte_pktmbuf_mtod(mbuf, uint8_t*); //把刚刚申请的mbuf指向的类型强制转换为一个char一个char的,方便操作

    jr_encode_arp_pkt(pktdata, dst_mac, sip, dip); //pktdata是一个位置,这个函数把编码好的字节们放入pktdata开始的那段位置上
    return mbuf;

}


#endif


#ifdef ENABLE_SEND


static int jr_encode_udp_pkt(uint8_t *msg, unsigned char *data, uint16_t total_len) {
    // 本函数功能:打包(encode)

    // 第一步 ethhdr 这玩意分为三部分:源mac、目的mac、类型
    struct rte_ether_hdr *eth = (struct rte_ether_hdr *)msg;
    rte_memcpy(eth->s_addr.addr_bytes, gSrcMac, RTE_ETHER_ADDR_LEN);
    rte_memcpy(eth->d_addr.addr_bytes, gDstMac, RTE_ETHER_ADDR_LEN);
    // 网络字节序转换:只要是两字节以上就要转换
    eth->ether_type = htons(RTE_ETHER_TYPE_IPV4);

    // 第二步 iphdr 分为……太长了看图吧
    // 首先计算偏移,msg刚刚传进来的类型是指向一个一个char的,可以加上sizeof(struct rte_ether_hdr),再强转为 (struct rte_ipv4_hdr *)类型
    struct rte_ipv4_hdr *ip = (struct rte_ipv4_hdr *)(msg + sizeof(struct rte_ether_hdr));
    ip->version_ihl = 0x45;
    ip->type_of_service = 0;
    ip->total_length = htons(total_len - sizeof(struct rte_ether_hdr));
    ip->packet_id = 0;
    ip->fragment_offset = 0;
    ip->time_to_live = 64;
    ip->next_proto_id = IPPROTO_UDP; //IPPROTO_UDP是内核的
    ip->src_addr = gSrcIp;
    ip->dst_addr = gDstIp;
    ip->hdr_checksum = 0; //不是废话
    ip->hdr_checksum = rte_ipv4_cksum(ip);

    // 第三步 udphdr
    // 首先偏移,同ip的理
    struct rte_udp_hdr *udp = (struct rte_udp_hdr *)(msg + sizeof(struct rte_ether_hdr) + sizeof(struct rte_ipv4_hdr));
    udp->src_port = gSrcPort;
    udp->dst_port = gDstPort;
    uint16_t udplen = total_len - sizeof(struct rte_ether_hdr) - sizeof(struct rte_ipv4_hdr);
    udp->dgram_len = htons(udplen);
    rte_memcpy((uint8_t*)(udp+1), data, udplen);
    udp->dgram_cksum = 0; //不是废话
    udp->dgram_cksum = rte_ipv4_udptcp_cksum(ip, udp);

    //调试

    struct in_addr addr;
    addr.s_addr = gSrcIp;
    printf("\n[send][udp协议]src: %s:%d, ", inet_ntoa(addr), ntohs(gSrcPort));

    addr.s_addr = gDstIp;
    printf("dst: %s:%d\n\n", inet_ntoa(addr), ntohs(gDstPort));

    return 0;



}
static struct rte_mbuf * jr_send(struct rte_mempool *mbuf_pool, uint8_t *data, uint16_t length) {
    // 本函数功能:mempool -> mbuf。
    // 解释:mempool和mbuf的区别在,内存池是一开始创建出的一大块,之后随用随取, 使用mempool的最小单位是mbuf。


    const unsigned total_len = 14 + 20 + 8 + length; //mbuf怎么用呢?先要知道从mempool中拿多长的一段(取多少数据)
    struct rte_mbuf *mbuf = rte_pktmbuf_alloc(mbuf_pool); //思考:怎么不带大小?
    if (!mbuf) {
        rte_exit(EXIT_FAILURE, "rte_pktmbuf_alloc出错\n");
    }

    mbuf->pkt_len = total_len;
    mbuf->data_len = total_len; //思考:这两个为什么设成一样的

    uint8_t *pktdata = rte_pktmbuf_mtod(mbuf, uint8_t*); //把刚刚申请的mbuf指向的类型强制转换为一个char一个char的,方便操作

    jr_encode_udp_pkt(pktdata, data, total_len); //pktdata是一个位置,这个函数把编码好的字节们放入pktdata开始的那段位置上
    return mbuf;

}

#endif
int main(int argc, char *argv[]) {

    // 初始化,主要是检查hugepage的设置,内存、cpu的分配等。就是在/usertools/dpdk-setup.sh中的一通设置
    if (rte_eal_init(argc, argv) < 0) {
        rte_exit(EXIT_FAILURE, "Error with EAL init\n");

    }

    // 内存池
    struct rte_mempool *mbuf_pool = rte_pktmbuf_pool_create("mbuf pool", NUM_MBUFS,
        0, 0, RTE_MBUF_DEFAULT_BUF_SIZE, rte_socket_id());
    if (mbuf_pool == NULL) {
        rte_exit(EXIT_FAILURE, "无法创建内存池\n");
    }

    // 端口初始化(实现在上面)这个port是网口的含义并非端口号
    jr_init_port(mbuf_pool);

#ifdef ENABLE_SEND
    rte_eth_macaddr_get(gDpdkPortId, (struct rte_ether_addr *)gSrcMac);
#endif

    while (1) {

        struct rte_mbuf *mbufs[BURST_SIZE]; //数组指针, mbufs尚未分配实际空间,空间从内存池来
        unsigned num_recvd = rte_eth_rx_burst(gDpdkPortId, 0, mbufs, BURST_SIZE);// 接收的是以太网数据帧
                                    // 参数1:端口<注意此端口不是tcp/udp的端口号,而是网络适配器eth0的端口> 
                                    //参数2:从哪个队列接收
                                    //参数3:接收后放到哪
        if (num_recvd > BURST_SIZE) {
            rte_exit(EXIT_FAILURE, "接收出错,溢出\n");
        }



        unsigned i = 0;
        for (i = 0;i < num_recvd;i++) {

            struct rte_ether_hdr *ehdr = rte_pktmbuf_mtod(mbufs[i], struct rte_ether_hdr*);// rte_pktmbuf_mtod是宏定义。参数1:内存地址 参数2:转换成什么类型
                    //// ehdr就是拿出的以太网数据

#ifdef ENABLE_ARP

            if (ehdr->ether_type == rte_cpu_to_be_16(RTE_ETHER_TYPE_ARP)) {



                // 解析这个arp报文并回复
                struct rte_arp_hdr *ahdr = rte_pktmbuf_mtod_offset(mbufs[i], struct rte_arp_hdr *, sizeof(struct rte_ether_hdr));

                // 调试
                struct in_addr addr_source, addr_target;
                addr_source.s_addr = ahdr->arp_data.arp_sip;

                printf("[recv][arp协议] src: %s ", inet_ntoa(addr_source));

                addr_target.s_addr = ahdr->arp_data.arp_tip;
                printf("target:%s\n",inet_ntoa(addr_target));

                if (ahdr->arp_data.arp_tip == gLocalIp) { // 如果arp问的就是自己的p地址

                    // 调试
                    printf("\t需回复\n");

                    struct rte_mbuf * arpbuf = jr_arp_send(mbuf_pool, ahdr->arp_data.arp_sha.addr_bytes, ahdr->arp_data.arp_tip, ahdr->arp_data.arp_sip);
                    rte_eth_tx_burst(gDpdkPortId, 0, &arpbuf, 1);// 真正的发送操作,第四个参数:发一个包,第二个参数:使用0号队列发送
                    rte_pktmbuf_free(arpbuf);
                    rte_pktmbuf_free(mbufs[i]);
                }
                continue;
            }

#endif

            // 此处可看到对接口处理函数封装的已经很完善了
            if (ehdr->ether_type != rte_cpu_to_be_16(RTE_ETHER_TYPE_IPV4)) {
                // 如果不是ip协议,跳过
                rte_pktmbuf_free(mbufs[i]);
                continue;
            }


            // 如果是ip协议,取出
            struct rte_ipv4_hdr *iphdr =  rte_pktmbuf_mtod_offset(mbufs[i], struct rte_ipv4_hdr *, 
            sizeof(struct rte_ether_hdr));

            if (iphdr->next_proto_id == IPPROTO_UDP) {

                struct rte_udp_hdr *udphdr = (struct rte_udp_hdr *)(iphdr + 1);





#ifdef ENABLE_SEND
                rte_memcpy(gDstMac, ehdr->s_addr.addr_bytes, RTE_ETHER_ADDR_LEN);
                rte_memcpy(&gSrcIp, &iphdr->dst_addr, sizeof(uint32_t));
                rte_memcpy(&gDstIp, &iphdr->src_addr, sizeof(uint32_t));
                rte_memcpy(&gSrcPort, &udphdr->dst_port, sizeof(uint16_t));
                rte_memcpy(&gDstPort, &udphdr->src_port, sizeof(uint16_t));
#endif
                uint16_t length = ntohs(udphdr->dgram_len); //经验:网络字节序2字节以上必须转,不管实际是什么序
                *((char*)udphdr + length) = '\0';

                struct in_addr addr;
                addr.s_addr = iphdr->src_addr;
                printf("[recv][udp协议]src: %s:%d, ", inet_ntoa(addr), ntohs(udphdr->src_port));

                addr.s_addr = iphdr->dst_addr;
                printf("dst: %s:%d, 内容:%s  length=%d\n", inet_ntoa(addr), ntohs(udphdr->dst_port), 
                    (ntohs(udphdr->dst_port) == 8888) ? (char *)(udphdr+1) : "略", length);

#ifdef ENABLE_SEND

                if (gSrcIp == gLocalIp){
                    struct rte_mbuf * txbuf = jr_send(mbuf_pool, (uint8_t *)(udphdr+1), length); 
                    rte_eth_tx_burst(gDpdkPortId, 0, &txbuf, 1);// 真正的发送操作,第四个参数:发一个包,第二个参数:使用0号队列发送
                    rte_pktmbuf_free(txbuf);
                }
#endif

                rte_pktmbuf_free(mbufs[i]);
            }

#ifdef ENABLE_ICMP

            if (iphdr->next_proto_id == IPPROTO_ICMP) {
                printf("[recv][icmp]");
                struct rte_icmp_hdr *icmphdr = (struct rte_icmp_hdr *)(iphdr + 1);
                // 在此只实现echo请求报文的回复,类型是08(RTE_IP_ICMP_ECHO_REQUEST)
                if (icmphdr->icmp_type == RTE_IP_ICMP_ECHO_REQUEST) {
                    printf("[request]\n");
                    struct rte_mbuf *txbuf = jr_send_icmp(
                        mbuf_pool, ehdr->s_addr.addr_bytes, 
                        iphdr->dst_addr, iphdr->src_addr, 
                        icmphdr->icmp_ident, icmphdr->icmp_seq_nb
                        );

                    rte_eth_tx_burst(gDpdkPortId, 0, &txbuf, 1);// 真正的发送操作,第四个参数:发一个包,第二个参数:使用0号队列发送
                    rte_pktmbuf_free(txbuf);                        

                }
                rte_pktmbuf_free(mbufs[i]);
            }
#endif


        }

    }

}