【Linux】简单版UDP服务器和TCP服务器

一.UDP

服务器端代码如下

   #include <stdio.h>
   #include <string.h>
   #include <sys/types.h>
   #include <sys/socket.h>
   #include <netinet/in.h>
   #include <arpa/inet.h>
   
   int main(int argc,char *argv[])
   {
      if(argc!=3){
          printf("Usage: %s [ip] [port]\n",argv[0]);
          return 1;
      }
  
      int sock=socket(AF_INET,SOCK_DGRAM,0);
      if(sock<0){
          perror("socket");
          return 2;
      }
  
      struct sockaddr_in local;
      local.sin_family=AF_INET;
      local.sin_port=htons(atoi(argv[2]));
      local.sin_addr.s_addr=inet_addr(argv[1]);//192.168.43.243
  
      if(bind(sock,(struct sockaddr*)&local,sizeof(local))<0){
          perror("bind");
          return 3;
      }
  
      char buf[1024];
      while(1){
          struct sockaddr_in client;
          socklen_t len =sizeof(client);
          ssize_t s=recvfrom(sock,buf,sizeof(buf)-1,0,\
                      (struct sockaddr*)&client,&len);
				if(s>0){
              buf[s]=0;
              printf("[%s:%d]: %s",inet_ntoa(client.sin_addr),\
                  ntohs(client.sin_port),buf);
              sendto(sock,buf,strlen(buf),0,\
                      (struct sockaddr*)&client,sizeof(client));
          }
      }
      return 0;
  }

客户端代码如下

   #include <unistd.h>
   #include <sys/types.h>
   #include <sys/socket.h>
   #include <netinet/in.h>
   #include <arpa/inet.h>
   #include <stdio.h>
   #include <string.h>
   
   int main(int argc,char *argv[])
   {
      if(argc != 3){
          printf("Usage: %s [server:ip] [server:port]\n",argv[0]);
          return 1;
      }
  
      int sock=socket(AF_INET,SOCK_DGRAM,0);
      if(sock<0){
          perror("sock");
          return 2;
      }
  
      char buf[1024];
      while(1){
          struct sockaddr_in server;
          server.sin_family=AF_INET;
          server.sin_port=htons(atoi(argv[2]));
          server.sin_addr.s_addr=inet_addr(argv[1]);
 
          printf("please enter:");
          ssize_t s=read(0,buf,sizeof(buf)-1);
          if(s>0){
              buf[s]=0;
              sendto(sock,buf,strlen(buf),0,(struct sockaddr*)&server,sizeof(server));
              recvfrom(sock,buf,sizeof(buf)-1,0,NULL,NULL);
              buf[s]=0;
              sendto(sock,buf,strlen(buf),0,(struct sockaddr*)&server,sizeof(server));
              recvfrom(sock,buf,sizeof(buf)-1,0,NULL,NULL);
				printf("server echo#  %s\n",buf);
          }
  
      }
      return 0;
  }

运行结果如下

二.TCP

服务器端代码如下

#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>

void serviceIO(int sock)
{
	char buf[1024];
	while(1){
		ssize_t s= read(sock,buf,sizeof(buf)-1);
		if(s>0){
			buf[s]=0;
			printf("client# %s\n",buf);
		}
		else if(s==0){
			printf("client quit\n");
			break;
		}
		else{
			perror("read");
			break;
		}
	}
	close(sock);
}


int main(int argc,char *argv[])
{
	if(argc != 3){
		printf("Usage: %s [ip] [port]\n",argv[0]);
		return 1;
	}

	int listen_sock=socket(AF_INET,SOCK_STREAM,0);
	if(listen_sock<0){
		perror("sock");
		return 2;
	}

	struct sockaddr_in local;
	local.sin_family=AF_INET;
	local.sin_port=htons(atoi(argv[2]));
	local.sin_addr.s_addr=inet_addr(argv[1]);

	if(bind(listen_sock,(struct sockaddr*)&local,sizeof(local))){
		perror("bind");
		return 3;
	}

	int s=listen(listen_sock,5);
	if(s<0){
		perror("listen");
		return 4;
	}

	for( ; ;){
		struct sockaddr_in client;
		socklen_t len=sizeof(client);
		int sock=accept(listen_sock,(struct sockaddr*)&client,&len);
		if(sock<0){
			perror("accept");
			continue;
		}
		printf("get a new link [%s:%d]...!\n",inet_ntoa(client.sin_addr),ntohs(client.sin_port));
		
		serviceIO(sock);
	}
	return 0;
}

客户端代码如下

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main(int argc,char *argv[])
{
	if(argc != 3){
		printf("Usage: %s [server.ip] [server.port]\n",argv[0]);
		return 1;
	}

	int sock=socket(AF_INET,SOCK_STREAM,0);
	if(sock<0){
		perror("socket");
		return 2;
	}

	struct sockaddr_in server;
	server.sin_family=AF_INET;
	server.sin_port=htons(atoi(argv[2]));	
	server.sin_addr.s_addr=inet_addr(argv[1]);

	if(connect(sock,(struct sockaddr*)&server,sizeof(server))<0){
		perror("connect");
		return 3;
	}

	char buf[1024];
	while(1){
		printf("please enter:");
		ssize_t s=read(0,buf,sizeof(buf)-1);
		
		if(s>0){
			buf[s]=0;
			write(sock,buf,strlen(buf));
		}
	}		
	return 0;
}

运行结果如下