代碼筆記 | UDP編程實現

 
/********** server.***********/
#include<sys/types.h> 
#include<sys/socket.h> 
#include<unistd.h> 
#include<netinet/in.h> 
#include<arpa/inet.h> 
#include<stdio.h> 
#include<stdlib.h> 
#include<errno.h> 
#include<netdb.h> 
#include<stdarg.h> 
#include<string.h> 
    
#define SERVER_PORT 8000 
#define BUFFER_SIZE 1024 
#define FILE_NAME_MAX_SIZE 512 
    
int main() 
{ 
     /* 創建UDP套接口 */
     struct sockaddr_in server_addr; 
     bzero(&server_addr, sizeof(server_addr)); 
     server_addr.sin_family = AF_INET; 
     server_addr.sin_addr.s_addr = htonl(INADDR_ANY); 
     server_addr.sin_port = htons(SERVER_PORT); 
        
     /* 創建socket */
     int server_socket_fd = socket(AF_INET, SOCK_DGRAM, 0); 
     if(server_socket_fd == -1) 
     { 
          perror("Create Socket Failed:"); 
          exit(1); 
     } 
        
     /* 綁定套接口 */
     if(-1 == (bind(server_socket_fd,(struct sockaddr*)&server_addr,sizeof(server_addr)))) 
     { 
         perror("Server Bind Failed:"); 
         exit(1); 
     } 
        
     /* 數據傳輸 */
     while(1) 
     {  
          /* 定義一個地址，用於捕獲客戶端地址 */
          struct sockaddr_in client_addr; 
          socklen_t client_addr_length = sizeof(client_addr); 
            
          /* 接收數據 */
          char buffer[BUFFER_SIZE]; 
          bzero(buffer, BUFFER_SIZE); 
          if(recvfrom(server_socket_fd, buffer, BUFFER_SIZE,0,(struct sockaddr*)&client_addr, &client_addr_length) == -1) 
          { 
           perror("Receive Data Failed:"); 
           exit(1); 
          } 
            
          /* 從buffer中拷貝出file_name */
          char file_name[FILE_NAME_MAX_SIZE+1]; 
          bzero(file_name,FILE_NAME_MAX_SIZE+1); 
          strncpy(file_name, buffer, strlen(buffer)>FILE_NAME_MAX_SIZE?FILE_NAME_MAX_SIZE:strlen(buffer)); 
          printf("%s\\n", file_name); 
     } 
       
     close(server_socket_fd); 
     return 0; 
} 
  
/***********client.c ************/
#include<sys/types.h> 
#include<sys/socket.h> 
#include<unistd.h> 
#include<netinet/in.h> 
#include<arpa/inet.h> 
#include<stdio.h> 
#include<stdlib.h> 
#include<errno.h> 
#include<netdb.h> 
#include<stdarg.h> 
#include<string.h> 
    
#define SERVER_PORT 8000 
#define BUFFER_SIZE 1024 
#define FILE_NAME_MAX_SIZE 512 
    
int main() 
{ 
     /* 服務端地址 */
     struct sockaddr_in server_addr; 
     bzero(&server_addr, sizeof(server_addr)); 
     server_addr.sin_family = AF_INET; 
     server_addr.sin_addr.s_addr = inet_addr("127.0.0.1"); 
     server_addr.sin_port = htons(SERVER_PORT); 
        
     /* 創建socket */
     int client_socket_fd = socket(AF_INET, SOCK_DGRAM, 0); 
     if(client_socket_fd < 0) 
     { 
          perror("Create Socket Failed:"); 
          exit(1); 
     } 
        
     /* 輸入文件名到緩衝區 */
     char file_name[FILE_NAME_MAX_SIZE+1]; 
     bzero(file_name, FILE_NAME_MAX_SIZE+1); 
     printf("Please Input File Name On Server:\\t"); 
     scanf("%s", file_name); 
        
     char buffer[BUFFER_SIZE]; 
     bzero(buffer, BUFFER_SIZE); 
     strncpy(buffer, file_name, strlen(file_name)>BUFFER_SIZE?BUFFER_SIZE:strlen(file_name)); 
        
     /* 發送文件名 */
     if(sendto(client_socket_fd, buffer, BUFFER_SIZE,0,(struct sockaddr*)&server_addr,sizeof(server_addr)) < 0) 
     { 
          perror("Send File Name Failed:"); 
          exit(1); 
     } 
        
     close(client_socket_fd); 
     return 0; 
}