目标
还记得前面是手动在windows的cmd中添加一条静态arp表项。如果没有此项，windows会广播arp请求报文，但在虚拟机上我们没做应答功能。
如果做了应答功能，那么就能完成mac地址的自动解析，就不用手动添加了。
在第二版代码身上修改的地方
定义全局变量：eth0网卡的ip地址
#define MAKE_IPV4_ADDR(a, b, c, d) (a + (b<<8) + (c<<16) + (d<<24))
static uint32_t gLocalIp = MAKE_IPV4_ADDR(192, 168, 3, 20);
编码数据帧的两个函数
#ifdef ENABLE_ARP
static int ng_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 * ng_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
ng_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
在判断报文类型时，首先判断是否为arp类型，若是，则解析并回复
#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;
addr.s_addr = ahdr->arp_data.arp_sip;
printf("[recv][arp协议] src: %s\n", inet_ntoa(addr));
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 = ng_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
效果
[recv][udp协议]src: 192.168.3.32:51423, dst: 239.255.255.250:1900, 内容：略 length=364
[recv][arp协议] src: 192.168.3.28
[recv][arp协议] src: 192.168.3.28
需回复
[recv][udp协议]src: 192.168.3.28:8080, dst: 192.168.3.20:8888, 内容：你好，我的冰糖雪梨 length=35
[send][udp协议]src: 192.168.3.20:8888, dst: 192.168.3.28:8080
[recv][udp协议]src: 192.168.3.28:8080, dst: 192.168.3.20:8888, 内容：你好，我的冰糖雪梨 length=35
[send][udp协议]src: 192.168.3.20:8888, dst: 192.168.3.28:8080
[recv][arp协议] src: 192.168.3.1
[recv][udp协议]src: 192.168.3.32:51423, dst: 239.255.255.250:1900, 内容：略 length=310
[recv][udp协议]src: 192.168.3.32:51423, dst: 239.255.255.250:1900, 内容：略 length=319
[recv][udp协议]src: 192.168.3.32:51423, dst: 239.255.255.250:1900, 内容：略 length=366
[recv][udp协议]src: 192.168.3.32:51423, dst: 239.255.255.250:1900, 内容：略 length=364
[recv][udp协议]src: 192.168.3.28:8080, dst: 192.168.3.20:8888, 内容：你好，我的冰糖雪梨 length=35
[send][udp协议]src: 192.168.3.20:8888, dst: 192.168.3.28:8080
[recv][udp协议]src: 192.168.3.32:5353, dst: 192.168.3.255:5353, 内容：略 length=1194
全部代码
#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
// 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, 3, 20);
//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 ng_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);
}
#ifdef ENABLE_ARP
static int ng_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 * ng_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
ng_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 ng_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 * ng_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
ng_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
ng_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;
addr.s_addr = ahdr->arp_data.arp_sip;
printf("[recv][arp协议] src: %s\n", inet_ntoa(addr));
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 = ng_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 = ng_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]);
}
}
}
}