linuxtcpclient.c

Linux网络编程中tcp客户端代码

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <strings.h>
#include <unistd.h> /* close */

#define SERVER_PORT 1500
#define MAX_MSG 100
#define maxsize 1024

int main (int argc, char *argv[]) {

  int sd, rc, i, fd;
  char buff[maxsize];
  struct sockaddr_in localAddr, servAddr;
  struct hostent *h;
  
  if(argc < 3) {
    printf("usage: %s <server> <filename>\n",argv[0]);
    exit(1);
  }

  h = gethostbyname(argv[1]);  //gethostbyname("127.0.0.1")
  if(h==NULL) {
    printf("unknown host '%s'\n",argv[1]);
    exit(1);
  }

	bzero(&servAddr,sizeof(servAddr));
  servAddr.sin_family = AF_INET;						        //servAddr.sin_family = h->h_addrtype;
	servAddr.sin_addr = *((struct in_addr *)h->h_addr);  //memcpy((char *) &servAddr.sin_addr.s_addr, h->h_addr_list[0], h->h_length);
  servAddr.sin_port = htons(SERVER_PORT);

  /* create socket */
  sd = socket(AF_INET, SOCK_STREAM, 0);
  if(sd<0) {
    perror("cannot open socket ");
    exit(1);
  }

  /* bind any port number */
  localAddr.sin_family = AF_INET;
  localAddr.sin_addr.s_addr = htonl(INADDR_ANY);
  localAddr.sin_port = htons(0);
  
  rc = bind(sd, (struct sockaddr *) &localAddr, sizeof(localAddr));
  if(rc<0) {
    printf("%s: cannot bind port TCP %u\n",argv[0],SERVER_PORT);
    perror("error ");
    exit(1);
  }
  				
  /* connect to server */
  rc = connect(sd, (struct sockaddr *) &servAddr, sizeof(servAddr));
  if(rc<0) {
    perror("cannot connect ");
    exit(1);
  }
  
  fd=open(argv[2],O_RDONLY);
  if(fd==-1)
    {   printf("file %s cannot open",argv[2]);
       exit(1);
    }
   while(1) {
    i=read(fd,buff,maxsize);
    rc = send(sd, buff, i, 0);
    
    if(rc<0) {
      perror("cannot send file ");
      close(sd);
      exit(1);
    
    }

    if(i!=maxsize) {
     printf("file has been sent \n");
     break;
         }

   
  }
close(fd);
close(sd);
exit(0);
  }