基本套接字编程—— -- UDP回射程序

Author: shineyr

udp_socket/client.c

@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+
+const int SERV_PORT = 6000;
+
+const int MAXLINE = 2048;
+void dg_cli(FILE *fp , int sockfd , const struct sockaddr *pservaddr , socklen_t servlen)
+{
+	int n;
+	char sendline[MAXLINE] , recvline[MAXLINE+1];
+	
+	while(fgets(sendline , MAXLINE , fp) != NULL)
+	{
+		if(sendto(sockfd , sendline , strlen(sendline) , 0 , pservaddr ,  servlen) < 0)
+		{
+			perror("sendto error");
+			exit(1);
+		}//if
+
+		if( ( n = recvfrom(sockfd , recvline , MAXLINE , 0 , NULL , NULL)) < 0)
+		{
+			perror("recvfrom error");
+			exit(1);
+		}//if
+
+		recvline[n] = '\0';
+		fputs(recvline , stdout);
+
+	}//while
+}
+
+int main(int argc , char **argv)
+{
+	int sockfd , t;
+	struct sockaddr_in servaddr;
+	if(argc != 2)
+	{
+		perror("usage: udpcli <IPaddress>");
+		exit(1);
+	}//if
+
+	bzero(&servaddr , sizeof(servaddr));
+	servaddr.sin_family = AF_INET;
+	servaddr.sin_port = htons(SERV_PORT);
+	if((t = inet_pton(AF_INET , argv[1], &servaddr.sin_addr)) <= 0)
+	{
+		perror("inet_pton error");
+		exit(1);
+	}//if
+	
+	if((sockfd = socket(AF_INET , SOCK_DGRAM , 0)) < 0)
+	{
+		perror("socket error");
+		exit(1);
+	}//if
+
+	dg_cli(stdin , sockfd , (struct sockaddr *)&servaddr , sizeof(servaddr));
+	exit(0);
+} 
+

udp_socket/server.c

@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <string.h>
+#include <sys/types.h>
+#include <netinet/ip.h>
+
+const int SERV_PORT = 6000;
+const int MAXLINE = 2048;
+
+void dg_echo(int sockfd , struct sockaddr *pcliaddr , socklen_t clilen)
+{
+	int n;
+	socklen_t len;
+	char mesg[MAXLINE];
+
+	for( ; ;)
+	{
+		len = clilen;
+		if((n = recvfrom(sockfd , mesg , MAXLINE , 0 , pcliaddr , &len))<0)
+		{
+			perror("recvfrom error");
+			exit(1);
+		}//if
+
+		if((n = sendto(sockfd , mesg , n , 0 , pcliaddr , len)) < 0)
+		{
+			perror("sendto error");
+			exit(1);
+		}//if
+	}//for
+
+}
+
+int main(int argc , char **argv)
+{
+	int sockfd;
+	struct sockaddr_in servaddr , cliaddr;
+
+	bzero(&servaddr , sizeof(servaddr));
+	servaddr.sin_family = AF_INET;
+	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
+	servaddr.sin_port = htons(SERV_PORT);
+
+	if((sockfd = socket(AF_INET , SOCK_DGRAM , 0)) < 0)
+	{
+		perror("socket error");
+		exit(1);
+	}//if
+
+	if(bind(sockfd , (struct sockaddr *)&servaddr , sizeof(servaddr)))
+	{
+		perror("bind error");
+		exit(1);
+	}//if
+
+	dg_echo(sockfd , (struct sockaddr *)&cliaddr , sizeof(cliaddr));	
+}