用户态协议栈04-定时arp-table的实现

2024-06-22 08:44
文章标签 实现 协议 arp 用户 table 04 定时

本文主要是介绍用户态协议栈04-定时arp-table的实现，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

之前有写过arp reply的实现，其中有写道，我们的系统内核中会维护一张ARP表，可以通过终端arp -a查看：

其中的dynamic和static是动态arp的类型，之前的udp实验就是添加了一条静态arp达到了发送的目的。在我们需要发送一个数据包的时候。指定好ip，内核会在arp表中寻找对应的ip，然后向他发送。在用户太协议栈中，DPDK同样需要维护一张arp表，实现类似的功能。

链表实现的ARP表


#ifndef LN_ARP_TABLE
#define LN_ARP_TABLE#include <rte_malloc.h>
#include <stdio.h>#define ARP_ENTRY_STATUS_DYNAMIC 0
#define ARP_ENTRY_STATUS_STATIC 1struct arp_entry {uint32_t ip;uint8_t hwaddr[RTE_ETHER_ADDR_LEN];int type;struct arp_entry* next;struct arp_entry* prev;
};struct arp_table {struct arp_entry* entries;int count;
}#define LL_ADD(item, list) do {		\item->next = NULL;		\item->prev = NULL;		\if(list != NULL) list->prev = NULL;		\list = item;	\
}while(0)#define LL_REMOVE(item, list) do {		\if(item->prev != NULL) item->prev->next = item->next;	\if(item->next != NULL) item->next->prev = item->prev;	\if(item == list) list = list->next;		\item->prev = item->next = NULL;		\
}while(0)static struct arp_table arpt = NULL;static struct arp_table* arp_table_instance() {if(arpt == NULL) {arpt = rte_malloc("arp table", sizeof(struct arp_table), 0);if(arpt == NULL) {rte_exit(EXIT_FAILURE, "Error with arp table malloc\n");}memset(arpt, 0, sizeof(struct arp_table));}return arpt;
}static uint8_t* arp_get_dst_macaddr(uint32_t dip) {struct arp_entry* ite;struct arp_table* table = arp_table_instance();for(ite = table->entries; ite != NULL; ite = ite->next) {if(dip == ite->ip) {return ite->hwaddr;}}return NULL;
}#endif

这里采用的是一个单例模式，线程安全等后面再迭代。这里实现的是一个头单项链表，只能头插。arp表一般来说不会太大，所以使用链表就可以了。或者说其实再大胆一点，数组也是可以的。代码中有LL_ADD和LL_REMOVE两个宏来进行链表的增加和删除节点。具体如何使用，需要看我们再主函数中的使用过程。

定时器

  • 为什么需要定时器？

    arp协议是一种广播协议，我们需要定时向局域网发起广播，公布自己的arp同时获取别人的arp来更新arp表。

这里是使用的DPDK提供出来的一个定时器组件，我直接抽离出来记录，避免代码繁多看起来眼花缭乱。

#define TIMER_RESOLUTION_CYCLES 120000000000ULL // 10ms * 1000 = 10s * 6

首先是有一个宏，这个有点像单片机里的知识。根据始终的频率，再一秒钟之内的滴答次数不一样，这里是记录一个抵达次数如果到达这个次数就广播arp。那这个次数是如何计算出来的呢？其实是再例程里面有的：

这里说20000000ULL是对应的10ms的时间间隔，所以可以算出，我们这里的宏是一分钟，广播一次。

rte_timer_subsystem_init();struct rte_timer arp_timer;
rte_timer_init(&arp_timer);uint64_t hz = rte_get_timer_hz();
unsigned lcore_id = rte_lcore_id();
rte_timer_reset(&arp_timer, hz, PERIODICAL, lcore_id, arp_request_timer_cb, mbuf_pool);
  • rte_timer_subsystem_init()函数会初始化相关的数据结构和配置，以便后续使用计时器功能
  • rte_get_timer_hz取得系统计时器的频率
  • rte_lcore_id返回执行当前代码的逻辑核心ID
  • arp_request_timer_cb是自己写的定时器执行的回调函数，执行业务逻辑
static uint64_t prev_tsc = 0, cur_tsc;
uint64_t diff_tsc;cur_tsc = rte_rdtsc();
diff_tsc = cur_tsc - prev_tsc;
if (diff_tsc > TIMER_RESOLUTION_CYCLES) {rte_timer_manage();prev_tsc = cur_tsc;
}
  • rte_timer_manage会检查所有注册的定时器，对超时任务进行处理。

具体实现

arp打包

static int ng_encode_arp_pkt(uint8_t *msg, uint16_t opcode, uint8_t *dst_mac, uint32_t sip, uint32_t dip) {// 1 ethhdrstruct rte_ether_hdr *eth = (struct rte_ether_hdr *)msg;rte_memcpy(eth->s_addr.addr_bytes, gSrcMac, RTE_ETHER_ADDR_LEN);if (!strncmp((const char *)dst_mac, (const char *)gDefaultArpMac, RTE_ETHER_ADDR_LEN)) {uint8_t mac[RTE_ETHER_ADDR_LEN] = {0x0};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);// 2 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(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;return 0;}static struct rte_mbuf *ng_send_arp(struct rte_mempool *mbuf_pool, uint16_t opcode, uint8_t *dst_mac, uint32_t sip, uint32_t dip) {const unsigned total_length = sizeof(struct rte_ether_hdr) + sizeof(struct rte_arp_hdr);struct rte_mbuf *mbuf = rte_pktmbuf_alloc(mbuf_pool);if (!mbuf) {rte_exit(EXIT_FAILURE, "rte_pktmbuf_alloc\n");}mbuf->pkt_len = total_length;mbuf->data_len = total_length;uint8_t *pkt_data = rte_pktmbuf_mtod(mbuf, uint8_t *);ng_encode_arp_pkt(pkt_data, opcode, dst_mac, sip, dip);return mbuf;
}

这里的两个函数相较于之前的添加了一个opcode参数，因为之前的是默认reply的，这里需要区别是reply还是request，其他没什么变化。

arp广播

static void arp_request_timer_cb(__attribute__((unused)) struct rte_timer *tim, void *arg) {struct rte_mempool *mbuf_pool = (struct rte_mempool *)arg;int i = 0;for (i = 1;i <= 254;i ++) {uint32_t dstip = (gLocalIp & 0x00FFFFFF) | (0xFF000000 & (i << 24));struct in_addr addr;addr.s_addr = dstip;printf("arp ---> src: %s \n", inet_ntoa(addr));struct rte_mbuf *arpbuf = NULL;uint8_t *dstmac = ng_get_dst_macaddr(dstip);if (dstmac == NULL) {arpbuf = ng_send_arp(mbuf_pool, RTE_ARP_OP_REQUEST, gDefaultArpMac, gLocalIp, dstip);} else {arpbuf = ng_send_arp(mbuf_pool, RTE_ARP_OP_REQUEST, dstmac, gLocalIp, dstip);}rte_eth_tx_burst(gDpdkPortId, 0, &arpbuf, 1);rte_pktmbuf_free(arpbuf);}}

这里是对网段中的所有ip发起request请求，我感觉这里有必要梳理一下这个dip的逻辑，毕竟这个代码看着怎么像寄存器[狗头]。假设本地ip是192.168.1.111：因为网络字节序是反的，所以(gLocalIp & 0x00FFFFFF)是把其中的111设为0；(0xFF000000 & (i << 24))从1-255分别将低位置1，这样就形成了目的ip；

完整代码

#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 "arp.h"#define ENABLE_SEND		1
#define ENABLE_ARP		1
#define ENABLE_ICMP		1
#define ENABLE_ARP_REPLY	1#define ENABLE_DEBUG		1#define ENABLE_TIMER		1#define NUM_MBUFS (4096-1)#define BURST_SIZE	32#define TIMER_RESOLUTION_CYCLES 120000000000ULL // 10ms * 1000 = 10s * 6 #if 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, 1, 184);static uint32_t gSrcIp; //
static uint32_t gDstIp;static uint8_t gSrcMac[RTE_ETHER_ADDR_LEN];
static uint8_t gDstMac[RTE_ETHER_ADDR_LEN];static uint16_t gSrcPort;
static uint16_t gDstPort;#endif#if ENABLE_ARP_REPLYstatic uint8_t gDefaultArpMac[RTE_ETHER_ADDR_LEN] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};#endifint 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) {uint16_t nb_sys_ports= rte_eth_dev_count_avail(); //if (nb_sys_ports == 0) {rte_exit(EXIT_FAILURE, "No Supported eth found\n");}struct rte_eth_dev_info dev_info;rte_eth_dev_info_get(gDpdkPortId, &dev_info); //const int num_rx_queues = 1;const int num_tx_queues = 1;struct rte_eth_conf port_conf = port_conf_default;rte_eth_dev_configure(gDpdkPortId, num_rx_queues, num_tx_queues, &port_conf);if (rte_eth_rx_queue_setup(gDpdkPortId, 0 , 1024, rte_eth_dev_socket_id(gDpdkPortId),NULL, mbuf_pool) < 0) {rte_exit(EXIT_FAILURE, "Could not setup RX queue\n");}#if ENABLE_SENDstruct 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, rte_eth_dev_socket_id(gDpdkPortId), &txq_conf) < 0) {rte_exit(EXIT_FAILURE, "Could not setup TX queue\n");}
#endifif (rte_eth_dev_start(gDpdkPortId) < 0 ) {rte_exit(EXIT_FAILURE, "Could not start\n");}}static int ng_encode_udp_pkt(uint8_t *msg, unsigned char *data, uint16_t total_len) {// encode // 1 ethhdrstruct 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_IPV4);// 2 iphdr 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; // ttl = 64ip->next_proto_id = IPPROTO_UDP;ip->src_addr = gSrcIp;ip->dst_addr = gDstIp;ip->hdr_checksum = 0;ip->hdr_checksum = rte_ipv4_cksum(ip);// 3 udphdr 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;udp->dgram_cksum = rte_ipv4_udptcp_cksum(ip, udp);struct in_addr addr;addr.s_addr = gSrcIp;printf(" --> src: %s:%d, ", inet_ntoa(addr), ntohs(gSrcPort));addr.s_addr = gDstIp;printf("dst: %s:%d\n", inet_ntoa(addr), ntohs(gDstPort));return 0;
}static struct rte_mbuf * ng_send_udp(struct rte_mempool *mbuf_pool, uint8_t *data, uint16_t length) {// mempool --> mbufconst unsigned total_len = length + 42;struct rte_mbuf *mbuf = rte_pktmbuf_alloc(mbuf_pool);if (!mbuf) {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_udp_pkt(pktdata, data, total_len);return mbuf;}#if ENABLE_ARPstatic int ng_encode_arp_pkt(uint8_t *msg, uint16_t opcode, uint8_t *dst_mac, uint32_t sip, uint32_t dip) {// 1 ethhdrstruct rte_ether_hdr *eth = (struct rte_ether_hdr *)msg;rte_memcpy(eth->s_addr.addr_bytes, gSrcMac, RTE_ETHER_ADDR_LEN);if (!strncmp((const char *)dst_mac, (const char *)gDefaultArpMac, RTE_ETHER_ADDR_LEN)) {uint8_t mac[RTE_ETHER_ADDR_LEN] = {0x0};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);// 2 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(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;return 0;}static struct rte_mbuf *ng_send_arp(struct rte_mempool *mbuf_pool, uint16_t opcode, uint8_t *dst_mac, uint32_t sip, uint32_t dip) {const unsigned total_length = sizeof(struct rte_ether_hdr) + sizeof(struct rte_arp_hdr);struct rte_mbuf *mbuf = rte_pktmbuf_alloc(mbuf_pool);if (!mbuf) {rte_exit(EXIT_FAILURE, "rte_pktmbuf_alloc\n");}mbuf->pkt_len = total_length;mbuf->data_len = total_length;uint8_t *pkt_data = rte_pktmbuf_mtod(mbuf, uint8_t *);ng_encode_arp_pkt(pkt_data, opcode, dst_mac, sip, dip);return mbuf;
}#endif#if ENABLE_ICMPstatic uint16_t ng_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;
}static int ng_encode_icmp_pkt(uint8_t *msg, uint8_t *dst_mac,uint32_t sip, uint32_t dip, uint16_t id, uint16_t seqnb) {// 1 etherstruct 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);// 2 ipstruct 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(sizeof(struct rte_ipv4_hdr) + sizeof(struct rte_icmp_hdr));ip->packet_id = 0;ip->fragment_offset = 0;ip->time_to_live = 64; // ttl = 64ip->next_proto_id = IPPROTO_ICMP;ip->src_addr = sip;ip->dst_addr = dip;ip->hdr_checksum = 0;ip->hdr_checksum = rte_ipv4_cksum(ip);// 3 icmp 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 = id;icmp->icmp_seq_nb = seqnb;icmp->icmp_cksum = 0;icmp->icmp_cksum = ng_checksum((uint16_t*)icmp, sizeof(struct rte_icmp_hdr));return 0;
}static struct rte_mbuf *ng_send_icmp(struct rte_mempool *mbuf_pool, uint8_t *dst_mac,uint32_t sip, uint32_t dip, uint16_t id, uint16_t seqnb) {const unsigned total_length = sizeof(struct rte_ether_hdr) + sizeof(struct rte_ipv4_hdr) + sizeof(struct rte_icmp_hdr);struct rte_mbuf *mbuf = rte_pktmbuf_alloc(mbuf_pool);if (!mbuf) {rte_exit(EXIT_FAILURE, "rte_pktmbuf_alloc\n");}mbuf->pkt_len = total_length;mbuf->data_len = total_length;uint8_t *pkt_data = rte_pktmbuf_mtod(mbuf, uint8_t *);ng_encode_icmp_pkt(pkt_data, dst_mac, sip, dip, id, seqnb);return mbuf;}#endifstatic 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);
}#if ENABLE_TIMERstatic void
arp_request_timer_cb(__attribute__((unused)) struct rte_timer *tim,void *arg) {struct rte_mempool *mbuf_pool = (struct rte_mempool *)arg;#if 0struct rte_mbuf *arpbuf = ng_send_arp(mbuf_pool, RTE_ARP_OP_REQUEST, 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);rte_pktmbuf_free(arpbuf);#endifint i = 0;for (i = 1;i <= 254;i ++) {uint32_t dstip = (gLocalIp & 0x00FFFFFF) | (0xFF000000 & (i << 24));struct in_addr addr;addr.s_addr = dstip;printf("arp ---> src: %s \n", inet_ntoa(addr));struct rte_mbuf *arpbuf = NULL;uint8_t *dstmac = ng_get_dst_macaddr(dstip);if (dstmac == NULL) {arpbuf = ng_send_arp(mbuf_pool, RTE_ARP_OP_REQUEST, gDefaultArpMac, gLocalIp, dstip);} else {arpbuf = ng_send_arp(mbuf_pool, RTE_ARP_OP_REQUEST, dstmac, gLocalIp, dstip);}rte_eth_tx_burst(gDpdkPortId, 0, &arpbuf, 1);rte_pktmbuf_free(arpbuf);}}#endifint main(int argc, char *argv[]) {if (rte_eal_init(argc, argv) < 0) {rte_exit(EXIT_FAILURE, "Error with EAL init\n");}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);rte_eth_macaddr_get(gDpdkPortId, (struct rte_ether_addr *)gSrcMac);#if ENABLE_TIMERrte_timer_subsystem_init();struct rte_timer arp_timer;rte_timer_init(&arp_timer);uint64_t hz = rte_get_timer_hz();unsigned lcore_id = rte_lcore_id();rte_timer_reset(&arp_timer, hz, PERIODICAL, lcore_id, arp_request_timer_cb, mbuf_pool);#endifwhile (1) {struct rte_mbuf *mbufs[BURST_SIZE];unsigned num_recvd = rte_eth_rx_burst(gDpdkPortId, 0, mbufs, BURST_SIZE);if (num_recvd > BURST_SIZE) {rte_exit(EXIT_FAILURE, "Error receiving from eth\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*);#if ENABLE_ARPif (ehdr->ether_type == rte_cpu_to_be_16(RTE_ETHER_TYPE_ARP)) {struct rte_arp_hdr *ahdr = rte_pktmbuf_mtod_offset(mbufs[i], struct rte_arp_hdr *, sizeof(struct rte_ether_hdr));struct in_addr addr;addr.s_addr = ahdr->arp_data.arp_tip;printf("arp ---> src: %s ", inet_ntoa(addr));addr.s_addr = gLocalIp;printf(" local: %s \n", inet_ntoa(addr));if (ahdr->arp_data.arp_tip == gLocalIp) {if (ahdr->arp_opcode == rte_cpu_to_be_16(RTE_ARP_OP_REQUEST)) {printf("arp --> request\n");struct rte_mbuf *arpbuf = 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);rte_eth_tx_burst(gDpdkPortId, 0, &arpbuf, 1);rte_pktmbuf_free(arpbuf);} else if (ahdr->arp_opcode == rte_cpu_to_be_16(RTE_ARP_OP_REPLY)) {printf("arp --> reply\n");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);if (entry) {memset(entry, 0, sizeof(struct arp_entry));entry->ip = ahdr->arp_data.arp_sip;rte_memcpy(entry->hwaddr, ahdr->arp_data.arp_sha.addr_bytes, RTE_ETHER_ADDR_LEN);entry->type = 0;LL_ADD(entry, table->entries);table->count ++;}}
#if ENABLE_DEBUGstruct 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->hwaddr);printf(" ip: %s \n", inet_ntoa(addr));}
#endifrte_pktmbuf_free(mbufs[i]);}continue;} }
#endifif (ehdr->ether_type != rte_cpu_to_be_16(RTE_ETHER_TYPE_IPV4)) {continue;}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);#if 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));#endifuint16_t length = ntohs(udphdr->dgram_len);*((char*)udphdr + length) = '\0';struct in_addr addr;addr.s_addr = iphdr->src_addr;printf("src: %s:%d, ", inet_ntoa(addr), ntohs(udphdr->src_port));addr.s_addr = iphdr->dst_addr;printf("dst: %s:%d, %s\n", inet_ntoa(addr), ntohs(udphdr->dst_port), (char *)(udphdr+1));#if ENABLE_SENDstruct rte_mbuf *txbuf = ng_send_udp(mbuf_pool, (uint8_t *)(udphdr+1), length);rte_eth_tx_burst(gDpdkPortId, 0, &txbuf, 1);rte_pktmbuf_free(txbuf);#endifrte_pktmbuf_free(mbufs[i]);}#if ENABLE_ICMPif (iphdr->next_proto_id == IPPROTO_ICMP) {struct rte_icmp_hdr *icmphdr = (struct rte_icmp_hdr *)(iphdr + 1);struct in_addr addr;addr.s_addr = iphdr->src_addr;printf("icmp ---> src: %s ", inet_ntoa(addr));if (icmphdr->icmp_type == RTE_IP_ICMP_ECHO_REQUEST) {addr.s_addr = iphdr->dst_addr;printf(" local: %s , type : %d\n", inet_ntoa(addr), icmphdr->icmp_type);struct rte_mbuf *txbuf = ng_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);rte_pktmbuf_free(txbuf);rte_pktmbuf_free(mbufs[i]);}}#endif}#if ENABLE_TIMERstatic uint64_t prev_tsc = 0, cur_tsc;uint64_t diff_tsc;cur_tsc = rte_rdtsc();diff_tsc = cur_tsc - prev_tsc;if (diff_tsc > TIMER_RESOLUTION_CYCLES) {rte_timer_manage();prev_tsc = cur_tsc;}#endif}}

写在最后

  1. 后续对当前代码进行一些架构优化，并且添加别的协议，tcp还是比较麻烦的
  2. 昨天去面试，是一家头部的智能家具公司。虽然说应该是过了，但是回答的比较业余，要把八股文提上日程了哈哈哈。

这篇关于用户态协议栈04-定时arp-table的实现的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！


http://www.chinasem.cn/article/1083808。

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