網絡編程client和server

翻譯了那麼多章《Beej’s Guide Network to Programming》我們有必要自己動手寫一個簡單的客戶端和服務器端的程序！

        Client Side:

                           getaddrinfo() -> socket() -> connect() -> recv()

        code:
#include <stdio.h>  
#include <string.h>  
#include <sys/types.h>  
#include <sys/socket.h>  
#include <arpa/inet.h>  
#include <netdb.h>  
 
#define SERVIP   "192.168.56.112"  
#define SERVPORT "2349"  
 
int main(int argc, char *argv[]) 
{ 
    struct addrinfo hints, *res; 
    int status; 
    int sockfd; 
    int connSta; 
     
    int recvSta; 
    char buffer[1024]; 
    int len; 
     
    char ipstr[INET_ADDRSTRLEN]; 
    void *addr; 
     
    if (argc != 3) { 
        fprintf(stderr, "Usage: Not Server IP And Port!"); 
        return 1; 
    } 
     
    memset(&hints, 0, sizeof(hints)); 
    hints.ai_family = AF_UNSPEC; 
    hints.ai_socktype = SOCK_STREAM; 
     
    status = getaddrinfo(argv[1], argv[2], &hints, &res); 
     
    if (status != 0) { 
        fprintf(stderr, "Error, Server IP And Port!"); 
        return 2; 
    } 
     
    sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol); 
     
    if (sockfd == 0) { 
        fprintf(stderr, "Create, socket fail!"); 
        return 3;    
    } 
     
    connSta = connect(sockfd, res->ai_addr, res->ai_addrlen); 
     
    if (connSta != 0) { 
        fprintf(stderr, "Connect, Remote Host fail!"); 
        return 4; 
    } 
    else { 
        struct sockaddr_in *ipv4 = (struct sockaddr_in *)res->ai_addr; 
        addr = &(ipv4->sin_addr); 
 
        inet_ntop(res->ai_family, addr, ipstr, sizeof(ipstr)); 
             
        printf("Linked: Host = %s, Port = %d\n", ipstr, ntohs(ipv4->sin_port));   
    } 
     
     
    recvSta = recv(sockfd, buffer, sizeof(buffer), 0); 
     
    printf("\n%s\n", buffer); 
     
    freeaddrinfo(res); 
    close(sockfd); 
     
    return 0; 
} 
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netdb.h>

#define SERVIP   "192.168.56.112"
#define SERVPORT "2349"

int main(int argc, char *argv[])
{
 struct addrinfo hints, *res;
 int status;
 int sockfd;
 int connSta;
 
 int recvSta;
 char buffer[1024];
 int len;
 
 char ipstr[INET_ADDRSTRLEN];
 void *addr;
 
 if (argc != 3) {
  fprintf(stderr, "Usage: Not Server IP And Port!");
  return 1;
 }
 
 memset(&hints, 0, sizeof(hints));
 hints.ai_family = AF_UNSPEC;
 hints.ai_socktype = SOCK_STREAM;
 
 status = getaddrinfo(argv[1], argv[2], &hints, &res);
 
 if (status != 0) {
  fprintf(stderr, "Error, Server IP And Port!");
  return 2;
 }
 
 sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
 
 if (sockfd == 0) {
  fprintf(stderr, "Create, socket fail!");
  return 3; 
 }
 
 connSta = connect(sockfd, res->ai_addr, res->ai_addrlen);
 
 if (connSta != 0) {
  fprintf(stderr, "Connect, Remote Host fail!");
  return 4;
 }
 else {
  struct sockaddr_in *ipv4 = (struct sockaddr_in *)res->ai_addr;
  addr = &(ipv4->sin_addr);

  inet_ntop(res->ai_family, addr, ipstr, sizeof(ipstr));
   
  printf("Linked: Host = %s, Port = %d\n", ipstr, ntohs(ipv4->sin_port)); 
 }
 
 
 recvSta = recv(sockfd, buffer, sizeof(buffer), 0);
 
 printf("\n%s\n", buffer);
 
 freeaddrinfo(res);
 close(sockfd);
 
 return 0;
}

          Server Side:

                               getaddrinfo() -> socket() -> bind() -> listen() -> accept() -> send()

         code:

         #include <stdio.h>  
#include <string.h>  
#include <sys/types.h>  
#include <sys/socket.h>  
#include <netdb.h>  
#include <arpa/inet.h>  
 
#define SERVPORT "2349"  
 
int main(int argc, char *argv[]) 
{ 
    struct addrinfo hints, *res; 
    int status; 
    int sockfd; 
     
    int connFd; 
    struct sockaddr_in cliAddr; 
     
    int sendSta; 
    char *msg; 
     
    if (argc != 2) { 
        fprintf(stderr, "Usage: Not found Read File"); 
        return 1; 
    } 
     
    memset(&hints, 0, sizeof(hints)); 
    hints.ai_family = AF_UNSPEC; 
    hints.ai_socktype = SOCK_STREAM; 
    hints.ai_flags = AI_PASSIVE; 
     
    status = getaddrinfo(NULL, SERVPORT, &hints, &res); 
     
    if (status != 0) { 
        fprintf(stderr, "getaddrinfo, fail!"); 
        return 2; 
    } 
     
    sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol); 
     
    bind(sockfd, res->ai_addr, res->ai_addrlen); 
     
    listen(sockfd, 5); 
     
    printf("======== Please Wait Client =========\n"); 
     
    while(1) { // loop forever!  
        char ipstr[INET_ADDRSTRLEN]; 
        void *addr; 
         
        int len = sizeof(cliAddr); 
        connFd = accept(sockfd, (struct sockaddr *)&cliAddr, &len); 
         
        /* View Client IP */ 
        struct sockaddr_in *ipv4 = (struct sockaddr_in *)&cliAddr; 
        addr = &(ipv4->sin_addr); 
     
        inet_ntop(AF_INET, addr, ipstr, sizeof(ipstr)); 
        printf("client: %s\n", ipstr); 
         
        /* Copy Data */ 
        msg = "Hello world!"; 
        sendSta = send(connFd, msg, strlen(msg), 0); 
         
        close(connFd); 
    } 
     
    close(sockfd); 
    return 0; 
} 

 摘自 xiaobin_HLJ80的專欄