请给出一段ethernet协议中如何配置dma传输的描述符实例C代码?
时间: 2023-03-15 17:27:41 浏览: 125
以下是在Ethernet协议中配置DMA传输描述符的C代码示例:/* 初始化DMA传输描述符 */
struct eth_dma_desc {
uint32_t status;
uint32_t cntrl;
uint32_t data;
uint32_t next;
};
struct eth_dma_desc eth_dma_desc[2];
eth_dma_desc[0].status = 0;
eth_dma_desc[0].cntrl = 0;
eth_dma_desc[0].data = 0;
eth_dma_desc[0].next = (uint32_t)ð_dma_desc[1];
eth_dma_desc[1].status = 0;
eth_dma_desc[1].cntrl = 0;
eth_dma_desc[1].data = 0;
eth_dma_desc[1].next = (uint32_t)ð_dma_desc[0];
相关问题
请给出rarp协议的C++代码实现
RARP协议是一个过时的协议,现在已经很少使用了。以下是一个简单的C++代码实现,仅供参考:
```c++
#include <iostream>
#include <cstring>
using namespace std;
// RARP协议包格式
struct RARP_Packet {
uint16_t hardware_type; // 硬件类型
uint16_t protocol_type; // 协议类型
uint8_t hardware_size; // 硬件地址长度
uint8_t protocol_size; // 协议地址长度
uint16_t opcode; // 操作码
uint8_t sender_hardware_addr[6]; // 发送方硬件地址
uint8_t sender_protocol_addr[4]; // 发送方协议地址
uint8_t target_hardware_addr[6]; // 目标硬件地址
uint8_t target_protocol_addr[4]; // 目标协议地址
};
int main() {
// 创建RARP包
RARP_Packet packet;
memset(&packet, 0, sizeof(packet));
packet.hardware_type = htons(1); // Ethernet硬件类型
packet.protocol_type = htons(0x0800); // IPv4协议类型
packet.hardware_size = 6; // 硬件地址长度为6字节
packet.protocol_size = 4; // 协议地址长度为4字节
packet.opcode = htons(3); // RARP请求操作码
memcpy(packet.sender_hardware_addr, "\x00\x11\x22\x33\x44\x55", 6); // 发送方MAC地址
memcpy(packet.sender_protocol_addr, "\xc0\xa8\x01\x01", 4); // 发送方IP地址
memset(packet.target_hardware_addr, 0xff, 6); // 目标硬件地址为全1
memcpy(packet.target_protocol_addr, "\xc0\xa8\x01\x02", 4); // 目标IP地址
// 发送RARP包
// ...
return 0;
}
```
给我一段arp捕获的C语言代码
以下是一段基于WinPcap的ARP捕获的C语言代码:
```
#include <pcap.h>
#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <netinet/if_ether.h>
#include <netinet/in.h>
void arp_callback(u_char *args, const struct pcap_pkthdr *header, const u_char *packet) {
struct ether_header *eth_header = (struct ether_header *) packet;
if (ntohs(eth_header->ether_type) == ETHERTYPE_ARP) {
printf("ARP packet captured:\n");
printf("Source MAC: %02x:%02x:%02x:%02x:%02x:%02x\n", eth_header->ether_shost[0], eth_header->ether_shost[1], eth_header->ether_shost[2], eth_header->ether_shost[3], eth_header->ether_shost[4], eth_header->ether_shost[5]);
printf("Destination MAC: %02x:%02x:%02x:%02x:%02x:%02x\n", eth_header->ether_dhost[0], eth_header->ether_dhost[1], eth_header->ether_dhost[2], eth_header->ether_dhost[3], eth_header->ether_dhost[4], eth_header->ether_dhost[5]);
struct arphdr *arp_header = (struct arphdr *)(packet + sizeof(struct ether_header));
printf("Source IP: %s\n", inet_ntoa(*(struct in_addr *)arp_header->arp_spa));
printf("Destination IP: %s\n", inet_ntoa(*(struct in_addr *)arp_header->arp_tpa));
}
}
int main(int argc, char *argv[]) {
char errbuf[PCAP_ERRBUF_SIZE];
pcap_t *handle = pcap_open_live("eth0", BUFSIZ, 1, 1000, errbuf);
if (handle == NULL) {
fprintf(stderr, "Could not open device %s: %s\n", "eth0", errbuf);
exit(EXIT_FAILURE);
}
if (pcap_datalink(handle) != DLT_EN10MB) {
fprintf(stderr, "Device %s doesn't provide Ethernet headers - not supported\n", "eth0");
exit(EXIT_FAILURE);
}
struct bpf_program fp;
char filter_exp[] = "arp";
bpf_u_int32 net;
if (pcap_compile(handle, &fp, filter_exp, 0, net) == -1) {
fprintf(stderr, "Couldn't parse filter %s: %s\n", filter_exp, pcap_geterr(handle));
exit(EXIT_FAILURE);
}
if (pcap_setfilter(handle, &fp) == -1) {
fprintf(stderr, "Couldn't install filter %s: %s\n", filter_exp, pcap_geterr(handle));
exit(EXIT_FAILURE);
}
pcap_loop(handle, -1, arp_callback, NULL);
pcap_close(handle);
return 0;
}
```
这段代码首先打开了网络接口设备 eth0,并设置了过滤器只捕获 ARP 协议的数据包。然后通过 pcap_loop 函数循环捕获数据包,并通过 arp_callback 函数对捕获的 ARP 数据包进行处理。在 arp_callback 函数中,首先解析出数据包中的以太网头部和 ARP 头部,然后打印出源 MAC 地址、目的 MAC 地址、源 IP 地址和目的 IP 地址。