linux udp协议服务器，客户端socket使用

下面只是简单的写了一下小例子，通常和多线程配合使用，还有tcp的例子，总结一下也记录下来。

服务器端代码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
int main(int argc, char *argv[])
{
int sock;
//sendto中使用的对方地址
struct sockaddr_in toAddr;
//在recvfrom中使用的对方主机地址
struct sockaddr_in fromAddr;
int recvLen;
unsigned int addrLen;
char recvBuffer[128];
sock = socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
if(sock < 0)
{
 printf("创建套接字失败了.\r\n");
 exit(0);
}
memset(&fromAddr,0,sizeof(fromAddr));
fromAddr.sin_family=AF_INET;
fromAddr.sin_addr.s_addr=htonl(INADDR_ANY);
fromAddr.sin_port = htons(4000);
if(bind(sock,(struct sockaddr*)&fromAddr,sizeof(fromAddr))<0)
{
 printf("bind() 函数使用失败了.\r\n");
 close(sock);
 exit(1);
}
while(1){
addrLen = sizeof(toAddr);
if((recvLen = recvfrom(sock,recvBuffer,128,0,(struct sockaddr*)&toAddr,&addrLen))<0)
{
 printf("()recvfrom()函数使用失败了.\r\n");
 close(sock);
 exit(1);
}
else
printf("received string %s \n",recvBuffer);

if(sendto(sock,recvBuffer,recvLen,0,(struct sockaddr*)&toAddr,sizeof(toAddr))!=recvLen){
printf("sendto fail\r\n");
else
printf("sent string %s \n",recvBuffer);
close(sock);
exit(0);
}
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return 0;
}

客户端代码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
int main(int argc, char *argv[])
{
if(argc < 2)
{
 printf("请输入要传送的内容.\r\n");
 exit(0);
}
int sock;
//sendto中使用的对方地址
struct sockaddr_in toAddr;
//在recvfrom中使用的对方主机地址
struct sockaddr_in fromAddr;
unsigned int fromLen;
char recvBuffer[128];
sock = socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
if(sock < 0)
{
 printf("创建套接字失败了.\r\n");
 exit(1);
}
memset(&toAddr,0,sizeof(toAddr));
toAddr.sin_family=AF_INET;
toAddr.sin_addr.s_addr=inet_addr("127.0.0.1");
toAddr.sin_port = htons(4000);
while(1){
char mess[100];
puts("please input the message you want to send");
scanf("%s",mess);
if(sendto(sock,mess,strlen(mess),0,(struct sockaddr*)&toAddr,sizeof(toAddr)) != strlen(mess))
{
 printf("sendto() 函数使用失败了.\r\n");
 close(sock);
 exit(1);
}
else
printf("sent to client srting:%s\n",mess);
fromLen = sizeof(fromAddr);
if(recvfrom(sock,recvBuffer,128,0,(struct sockaddr*)&fromAddr,&fromLen)<0)
{
 printf("()recvfrom()函数使用失败了.\r\n");
 close(sock);
 exit(1);
}
else
printf("received from server srting:%s\n",recvBuffer);
}
close(sock);
return 0}