1、当前不知道对端mac地址发送arp请求时：
1）以太网帧中目的mac是ff:ff:ff:ff:ff:ff
2）arp报文中的目的mac是00:00:00:00:00:00
2、arp探测报文，定时发送arp请求，判断arp是否更新
该报文是单播，且以太网帧中目的mac和arp中的目的mac都是arp表中记录的mac
以下代码以链表实现了一个arptable，启动一个定时器往外发送arp请求，将获取到的ip->mac映射存到arptable中。
#ifndef __NG_ARP_H__
#define __NG_ARP_H__
#include <rte_malloc.h>
#define ARY_ENTRY_STATUS_DYNAMIC 0
#define ARY_ENTRY_STATUS_STATIC 1
//链表头插法
#define LL_ADD(item, list) do { \
item->prev = NULL; \
item->next = list; \
if (list != NULL) list->prev = item; \
list = item; \
}while(0)
//链表删除节点
#define LL_REMOVE(item, list) do } { \
if (item->prev != NULL) item->prev->next = item->next; \
if (item->next != NULL) item->next->pre = item->pre; \
if (list == item) list = item->next; \
item->prev = item->next = NULL; \
}while(0)
struct arp_entry {
uint32_t ip; //网络字节序
uint8_t hwadder[RTE_ETHER_ADDR_LEN];
uint8_t type;
struct arp_entry *next;
struct arp_entry *prev;
};
struct arp_table {
struct arp_entry *entries;
int count;
};
static struct arp_table *arpt = NULL;
//该函数参数中不加void，会告警 function declaration isn’t a prototype(该函数声明不是原型)
static struct arp_table *arp_table_instance(void) {
if (arpt == NULL) {
arpt = rte_malloc("arp_table", sizeof(struct arp_table), 0);
if (arpt == NULL) {
rte_exit(EXIT_FAILURE, "rte_malloc arp table failed");
}
memset(arpt, 0, sizeof(struct arp_table));
}
return arpt;
}
// 根据ip查找mac
static uint8_t* ng_get_dst_macaddr(uint32_t dip) {
struct arp_entry *iter = NULL;
struct arp_table *table = arp_table_instance();
for (iter = table->entries; iter != NULL; iter = iter->next) {
if (dip == iter->ip) {
return iter->hwadder;
}
}
return NULL;
}
#endif#include <rte_eal.h>
#include <rte_ethdev.h>
#include <rte_mbuf.h>
#include <rte_malloc.h>
#include <rte_timer.h>
#include <stdio.h>
#include <arpa/inet.h>
#include "arptable.h"
#define NUM_MBUFS (4096-1) // 内存池中 mbuf 的数量
#define BURST_SIZE 32
#define MAKE_IPV4_ADDR(a, b, c, d) (a + (b<<8) + (c<<16) + (d<<24))
#define TIMER_RESOLUTION_CYCLES 20000000000ULL //10ms * 1000
static uint32_t gLocalIp = MAKE_IPV4_ADDR(192, 168, 1, 5);//当前ip，网络字节序
static uint8_t gSrcMac[RTE_ETHER_ADDR_LEN];
static uint8_t gDefaultArpMac[RTE_ETHER_ADDR_LEN] = {0x0};
int gDpdkPortId = 0;
static const struct rte_eth_conf port_conf_default = {
.rxmode = {.max_rx_pkt_len = RTE_ETHER_MAX_LEN}
};
static void ng_init_port(struct rte_mempool *mbuf_pool) {
//dpdk绑定的网卡数量
uint16_t nb_sys_ports = rte_eth_dev_count_avail();
if (nb_sys_ports == 0) {
rte_exit(EXIT_FAILURE, "not support eth\n");
}
struct rte_eth_dev_info dev_info;
/*获取以太网设备的配置和状态信息。它通常用于初始化网络设备、
*配置网络设备或者获取网络设备的状态信息。
*这里的端口号和网卡是一一对应的
*/
rte_eth_dev_info_get(gDpdkPortId, &dev_info);
const int num_rx_queues = 1; //接收队列个数
const int num_tx_queues = 1; //发送队列个数
struct rte_eth_conf port_conf = port_conf_default;
rte_eth_dev_configure(gDpdkPortId, num_rx_queues, num_tx_queues, &port_conf);
// 0是0号接收队列
// 128是队列长度
if (rte_eth_rx_queue_setup(gDpdkPortId, 0, 128, rte_eth_dev_socket_id(gDpdkPortId), NULL, mbuf_pool) < 0) {
rte_exit(EXIT_FAILURE, "Could not setup RX queue\n");
}
struct rte_eth_txconf txq_conf = dev_info.default_txconf;
//offloads 成员是一个 64 位无符号整数，每个比特位表示不同的接收功能选项
txq_conf.offloads = port_conf.rxmode.offloads;
/* 0是0号发送队列
* 1024是队列长度
* 发送队列长度设置太小运行时会报错:Invalid value for nb_tx_desc(=128), should be: <= 4096, >= 512, and a product of 1
*/
if (rte_eth_tx_queue_setup(gDpdkPortId, 0, 1024, rte_eth_dev_socket_id(gDpdkPortId), &txq_conf) < 0) {
rte_exit(EXIT_FAILURE, "Could not setup TX queue\n");
}
if (rte_eth_dev_start(gDpdkPortId) < 0) {
rte_exit(EXIT_FAILURE, "Could not start\n");
}
}
static void ng_encode_arp_pkt(uint8_t *msg, uint16_t opcode, uint8_t *dst_mac, uint32_t sip, uint32_t dip) {
//设置以太网头
struct rte_ether_hdr *eth = (struct rte_ether_hdr *)msg;
rte_memcpy(eth->s_addr.addr_bytes, gSrcMac, RTE_ETHER_ADDR_LEN);
if (memcpy(gDefaultArpMac, dst_mac, RTE_ETHER_ADDR_LEN) == 0) {
uint8_t mac[RTE_ETHER_ADDR_LEN] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
rte_memcpy(eth->d_addr.addr_bytes, mac, RTE_ETHER_ADDR_LEN);
} else {
rte_memcpy(eth->d_addr.addr_bytes, dst_mac, RTE_ETHER_ADDR_LEN);
}
eth->ether_type = htons(RTE_ETHER_TYPE_ARP);
//设置arp报文
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(opcode);
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;
}
static void ng_send_arp(struct rte_mempool *mbuf_pool, uint16_t opcode, uint8_t *dst_mac,
uint32_t sip, uint32_t dip) {
const unsigned total_len = sizeof(struct rte_ether_hdr) + sizeof(struct rte_arp_hdr);
//从内存中申请一个mbuf
struct rte_mbuf *mbuf = rte_pktmbuf_alloc(mbuf_pool);
if (mbuf == NULL) {
rte_exit(EXIT_FAILURE, "rte_pktmbuf_alloc\n");
}
mbuf->pkt_len = total_len;
mbuf->data_len = total_len;
uint8_t *pktdata = rte_pktmbuf_mtod(mbuf, uint8_t*);
ng_encode_arp_pkt(pktdata, opcode, dst_mac, sip, dip);
rte_eth_tx_burst(gDpdkPortId, 0, &mbuf, 1);
rte_pktmbuf_free(mbuf);
}
// tim是定时器， arg是传给定时器的参数
static void
arp_request_timer_cb(__attribute__((unused)) struct rte_timer *tim,
__attribute__((unused)) void *arg)
{
puts("arp_request_timer_cb");
struct rte_mempool *mbuf_pool = (struct rte_mempool *)arg;
int i = 0;
for(i = 0; i < 255; i++) {
uint32_t dstip = (gLocalIp & 0x00FFFFFF) | (0xFF000000 & (i << 24));
uint8_t *dstmac = ng_get_dst_macaddr(dstip);
if (dstmac == NULL) {
// arphdr中目的mac是FF:FF:FF:FF:FF:FF，以太网中目的mac是00:00:00:00:00:00
ng_send_arp(mbuf_pool, RTE_ARP_OP_REQUEST, gDefaultArpMac,
gLocalIp, dstip);
} else {
ng_send_arp(mbuf_pool, RTE_ARP_OP_REQUEST, dstmac,
gLocalIp, dstip);
}
}
}
static void
print_ethaddr(const char *name, const struct rte_ether_addr *eth_addr)
{
char buf[RTE_ETHER_ADDR_FMT_SIZE];
rte_ether_format_addr(buf, RTE_ETHER_ADDR_FMT_SIZE, eth_addr);
printf("%s%s", name, buf);
}
int main(int argc, char *argv[]) {
/*dpdk初始化资源
*用于初始化 Environment Abstraction Layer (EAL)。EAL 是 DPDK 的一个核心组件，
*负责抽象和管理硬件和操作系统依赖性，使得上层应用可以在不同的硬件和操作系统上
*以统一的方式运行。
*/
if (rte_eal_init(argc, argv) < 0) {
rte_exit(EXIT_FAILURE, "Error with EAL initialization\n");
}
//内存池，接收的数据存在该内存池中
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, "Could not create mbuf pool\n");
}
ng_init_port(mbuf_pool);
//获取dpdk绑定的网卡源mac
rte_eth_macaddr_get(gDpdkPortId, (struct rte_ether_addr *)gSrcMac);
static struct rte_timer arp_timer;
uint64_t prev_tsc = 0, cur_tsc, diff_tsc;
/* init RTE timer library */
rte_timer_subsystem_init();
/* init timer structures */
rte_timer_init(&arp_timer);
/* load timer0, every second, on master lcore, reloaded automatically */
uint64_t hz = rte_get_timer_hz();
unsigned lcore_id = rte_lcore_id();
//PERIODICAL表示重复触发，SINGLE是单次触发
rte_timer_reset(&arp_timer, hz, PERIODICAL, lcore_id, arp_request_timer_cb, mbuf_pool);
while(1) {
struct rte_mbuf *mbufs[BURST_SIZE] = {0};
unsigned num_recvd = rte_eth_rx_burst(gDpdkPortId, 0, mbufs, BURST_SIZE);
if (num_recvd > BURST_SIZE) {
rte_exit(EXIT_FAILURE, "Error receive from eth\n");
}
unsigned int i = 0;
for (i = 0; i < num_recvd; i++) {
struct rte_ether_hdr *ehdr = rte_pktmbuf_mtod(mbufs[i], struct rte_ether_hdr*);
//arp是广播
if (ehdr->ether_type == rte_cpu_to_be_16(RTE_ETHER_TYPE_ARP)) {
struct rte_arp_hdr *ahdr = (struct rte_arp_hdr *)(ehdr + 1);
if (ahdr->arp_data.arp_tip == gLocalIp) {
if (ahdr->arp_opcode == rte_cpu_to_be_16(RTE_ARP_OP_REQUEST)) {
//处理arp请求报文
puts("arp request");
ng_send_arp(mbuf_pool, RTE_ARP_OP_REPLY, ahdr->arp_data.arp_sha.addr_bytes,
ahdr->arp_data.arp_tip, ahdr->arp_data.arp_sip);
} else if (ahdr->arp_opcode == rte_cpu_to_be_16(RTE_ARP_OP_REPLY)) {
//处理arp响应
puts("arp reply");
struct arp_table *table = arp_table_instance();
uint8_t *hwaddr = ng_get_dst_macaddr(ahdr->arp_data.arp_sip);
if (hwaddr == NULL) {
struct arp_entry *entry = rte_malloc("arp entry", sizeof(struct arp_entry), 0);
//如何内存分配失败，进程不退出，后续会重试
if (entry) {
memset(entry, 0, sizeof(struct arp_entry));
entry->ip = ahdr->arp_data.arp_sip;
rte_memcpy(entry->hwadder, ahdr->arp_data.arp_sha.addr_bytes, RTE_ETHER_ADDR_LEN);
entry->type = ARY_ENTRY_STATUS_DYNAMIC;
LL_ADD(entry, table->entries);
table->count++;
}
}
struct arp_entry *iter;
for (iter = table->entries; iter != NULL; iter = iter->next) {
struct in_addr addr;
addr.s_addr = iter->ip;
print_ethaddr("arp table --> mac: ", (struct rte_ether_addr *)iter->hwadder);
printf(" ip: %s \n", inet_ntoa(addr));
}
}
}
}
rte_pktmbuf_free(mbufs[i]);
}
cur_tsc = rte_rdtsc();
diff_tsc = cur_tsc - prev_tsc;
if (diff_tsc > TIMER_RESOLUTION_CYCLES) {
rte_timer_manage();
prev_tsc = cur_tsc;
}
}
return 0;
}
