Linux基础——socket的UDP实现

与TCP连接相差不多，UDP同样需要套接字socket产生。

注意:UDP中需要知道对方的IP及port，这样才能正确的传送数据。

UDP服务器实现代码如下:

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 #include <sys/socket.h>
 5 #include <sys/types.h>
 6 #include <netinet/in.h>
 7 #include <arpa/inet.h>
 8 #include <unistd.h>
 9 #define IP "192.168.0.124"
10 #define PORT 10000
11 int main(int argc,char *argv[])
12 {
13     int fd;
14     if((fd = socket(AF_INET,SOCK_DGRAM,0))==-1)
15     {
16         perror("socket");
17         exit(1);
18     }
19     struct sockaddr_in addr,addr_client;
20     memset(&addr,0,sizeof(addr));
21     memset(&addr_client,0,sizeof(addr_client));
22     int len = sizeof(addr_client);
23     addr.sin_family=AF_INET;
24     addr.sin_port=htons(PORT);
25     addr.sin_addr.s_addr=inet_addr(IP);
26     if(-1 == bind(fd,(struct sockaddr*)&addr,sizeof(addr)))
27     {
28         perror("bind");
29         exit(1);
30     }
31     char buf[128];
32     memset(buf,0,128);
33     recvfrom(fd,buf,128,0,(struct sockaddr*)&addr_client,&len);
34                 printf("recv : %s from  %s : %d
",buf,inet_ntoa(addr_client.sin_addr),ntohs(addr_client.sin_port));
35         if(fork()>0)
36         {
37             while(memset(buf,0,128),recvfrom(fd,buf,128,0,(struct sockaddr*)&addr_client,&len)>0)
38                 printf("recv : %s from  %s : %d
",buf,inet_ntoa(addr_client.sin_addr),ntohs(addr_client.sin_port));
39             exit(0);
40         }
41         while(memset(buf,0,128),fgets(buf,128,stdin)!=NULL)
42             sendto(fd,buf,strlen(buf),0,(struct sockaddr*)&addr_client,sizeof(addr));
43         wait(NULL);
44     close(fd);
45     return 0;
46 }

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客户端实现代码如下:

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 #include <unistd.h>
 5 #include <netinet/in.h>
 6 #include <sys/types.h>
 7 #include <sys/socket.h>
 8 #include <arpa/inet.h>
 9 #define IP "192.168.0.173"
10 #define PORT 9999
11 int main(int argc,char *argv[])
12 {
13     int fd;
14     if((fd = socket(AF_INET,SOCK_DGRAM,0))==-1 )
15     {
16         perror("socket");
17         exit(1);
18     }
19     struct sockaddr_in addr;
20     memset(&addr,0,sizeof(addr));
21     int len = sizeof(addr);
22     addr.sin_family = AF_INET;
23     addr.sin_port = htons(PORT);
24     addr.sin_addr.s_addr = inet_addr(IP);
25     char buf[128];
26     int sendn;
27         if(fork()==0)
28         {
29             while(memset(buf,0,128),fgets(buf,128,stdin)!=NULL)
30                 sendto(fd,buf,strlen(buf),0,(struct sockaddr*)&addr,len);
31             exit(0);
32         }
33         while(memset(buf ,0 ,128),recvfrom(fd,buf,128,0,(struct sockaddr*)&addr,&len)>0)
34             printf("recv : %s  form : %s:%d
",buf,inet_ntoa(addr.sin_addr),ntohs(addr.sin_port));
35         wait(NULL);
36     close(fd);
37     return 0;
38 }

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