使用libnet库封装数据包
安装库sudo apt-get install libnet-dev
1、数据包内存初始化
libnet_t *libnet_init(int injection_type, char *device, char *err_buf)
2、构造数据包, 由应用层UDP/TCP到MAC层的顺序构造
封装udp数据包的函数
libnet_ptag_t libnet_build_udp(u_int16_t sp,
u_int16_t dp,
u_int16_t len,
u_int16_t sum,
u_int8_t *payload,
u_int32_t payload_s,
libnet_t *l,
libnet_ptag_t ptag)
封装IP数据报的函数
libnet_ptag_t libnet_build_ipv4(u_int16_t ip_len, u_int8_t tos,
u_int16_t id, u_int16_t frag,
u_int8_t ttl, u_int8_t prot,
u_int16 sum, u_int32_t src,
u_int32_t dst, u_int8_t *payload,
u_int32_t payload_s,
libnet_t *l, libnet_ptag_t ptag)
封装mac数据包的函数
libnet_ptag_t libnet_build_ethernet(
u_int8_t *dst,
u_int8_t *src,
u_int16_t type,
u_int8_t *payload,
u_int32_t payload_s,
libnet_t *l,
libnet_ptag_t ptag)
3、发送数据
int libnet_write(libnet_t * l)
4、释放资源
void libnet_destroy(libnet_t *l);
代码示例:
#include <libnet.h>
#include <stdio.h>
#include <string.h>
int main(int argc, char const *argv[])
{
//1. 初始化libnet操作空间
libnet_t *net = libnet_init(LIBNET_LINK_ADV, "ens33", NULL);
if(net != NULL){
printf("libnet init ok\n");
// udp报文中的数据
unsigned char data[] = "hello, window for libnet!";
int datalen = strlen(data) % 2 == 0?strlen(data): strlen(data)+1;
//2.构造各层的数据报(从应用层)
//2.1 构造udp
if(libnet_build_udp(9000, 8000, 8+datalen, 0, data, datalen, net, 0) == -1){
printf("build udp fail!\n");
goto freenet;
}
// 2.2 构造IP报文
if(libnet_build_ipv4(20+8+datalen, 0, 0, 0, 32, 17, 0,
inet_addr("10.35.184.140"),
inet_addr("10.35.184.221"), NULL, 0, net, 0) == -1){
printf("build ip fail!\n");
goto freenet;
}
//2.3 构造mac报文
if(libnet_build_ethernet("4c:e1:73:47:16:3a", "00:0c:29:b0:8f:42", 0x0800, NULL, 0, net, 0) == -1){
printf("build ip fail!\n");
goto freenet;
}
// 3 发送数据
if(libnet_write(net) != -1){
printf("send ok\n");
}
freenet:
// 释放libnet空间
libnet_destroy(net);
}
return 0;
}