/rudp-sender.c 用rawsocket实现的发送UDP数据包工具。
//引用时，需要多源目的IP以及端口做些修改。linux下可以直接编译。
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <errno.h>
#define BUFLEN 38
#define PORT 8848
typedef struct ip_hdr{//ipv4头部
unsigned int ip_length:4; /*little-endian*/
unsigned int ip_version:4;
unsigned char ip_tos;
unsigned short ip_total_length;
unsigned short ip_id;
unsigned short ip_flags;
unsigned char ip_ttl;
unsigned char ip_protocol;
unsigned short ip_cksum;
unsigned int ip_source;
unsigned int ip_dest;
}ip_hdr;
typedef struct udp_hdr{//udp头部
unsigned short s_port;
unsigned short d_port;
unsigned short length;
unsigned short cksum;
}udp_hdr;
typedef struct psd_header{//伪头部，用于计算校验和
unsigned int s_ip;//source ip
unsigned int d_ip;//dest ip
unsigned char mbz;//0
unsigned char proto;//proto type
unsigned short plen;//length
}psd_header;
void swap(unsigned int *a, unsigned int *b)//交换
{
*a = (*a)^(*b);
*b = (*a)^(*b);
*a = (*a)^(*b);
}
unsigned short checksum(unsigned short* buffer, int size)//校验和
{
unsigned long cksum = 0;
while(size>1)
{
cksum += *buffer++;
size -= sizeof(unsigned short);
}
if(size)
{
cksum += *(unsigned char*)buffer;
}
cksum = (cksum>>16) + (cksum&0xffff); //将高16bit与低16bit相加
cksum += (cksum>>16); //将进位到高位的16bit与低16bit 再相加
return (unsigned short)(~cksum);
}
int main(int argc, char *argv[])
{
char buf[BUFLEN];
int sockfd = -1;
struct sockaddr_in host_addr;
if((sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_UDP))<0)
{
printf("socket() error!/n");
exit(1);
}
memset(&host_addr, 0, sizeof(host_addr));
host_addr.sin_family = AF_INET;
host_addr.sin_port = htons(PORT);
host_addr.sin_addr.s_addr = inet_addr("200.200.30.42");
const int on = 1;
if(setsockopt(sockfd, IPPROTO_IP, IP_HDRINCL, &on, sizeof(on))<0)
{
printf("setsockopt() error!/n");
exit(0);
}
int addr_len = sizeof(host_addr);
while(1)
{
ip_hdr *iphdr;
iphdr = (ip_hdr*)buf;
udp_hdr *udphdr;
udphdr = (udp_hdr*)(buf+20);
iphdr->ip_length = 5;
iphdr->ip_version= 4;
iphdr->ip_tos = 0;
iphdr->ip_total_length = htons(sizeof(buf));
iphdr->ip_id = 0;
iphdr->ip_flags = 0x40;
iphdr->ip_ttl = 0x40;
iphdr->ip_protocol = 0x11;
iphdr->ip_cksum = 0;
iphdr->ip_source = inet_addr("200.200.30.14");//源地址
iphdr->ip_dest = inet_addr("200.200.30.42");//目的地址
iphdr->ip_cksum = checksum((unsigned short*)buf, 20);
udphdr->s_port = htons(80);//源端口
udphdr->d_port = htons(1024);//目的端口
udphdr->length = htons(sizeof(buf)-20);
udphdr->cksum = 0;
psd_header psd;
psd.s_ip = iphdr->ip_source;
psd.d_ip = iphdr->ip_dest;
psd.mbz = 0;
psd.proto = 0x11;
psd.plen = udphdr->length;
char tmp[sizeof(psd)+ntohs(udphdr->length)];
memcpy(tmp, &psd, sizeof(psd));
memcpy(tmp+sizeof(psd), buf+20, sizeof(buf)-20);
udphdr->cksum = checksum((unsigned short*)tmp, sizeof(tmp));
int res =sendto(sockfd, buf, sizeof(buf), 0, (struct sockaddr*)&host_addr, sizeof(host_addr));
sleep(1);
}
return 0;
}