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我们必须编写自己的 arpa/inet.h 吗？

tag-icon • tag-icon c linux-headers
我们必须编写自己的 arpa/inet.h 吗？ 
#include <stdio.h>      /* standard C i/o facilities */
#include <stdlib.h>     /* needed for atoi() */
#include <unistd.h>     /* defines STDIN_FILENO, system calls,etc */
#include <sys/types.h>  /* system data type definitions */
#include <sys/socket.h> /* socket specific definitions */
#include <netinet/in.h> /* INET constants and stuff */
#include <arpa/inet.h>  /* IP address conversion stuff */
#include <netdb.h>      /* gethostbyname */



/* this routine echos any messages (UDP datagrams) received */

#define MAXBUF 1024*1024

void echo( int sd ) {
    int len,n;
    char bufin[MAXBUF];
    struct sockaddr_in remote;

    /* need to know how big address struct is, len must be set before the
       call to recvfrom!!! */

    len = sizeof(remote);

    while (1) {
      /* read a datagram from the socket (put result in bufin) */
      n=recvfrom(sd,bufin,MAXBUF,0,(struct sockaddr *)&remote,&len);

      /* print out the address of the sender */
      printf("Got a datagram from %s port %d\n",
             inet_ntoa(remote.sin_addr), ntohs(remote.sin_port));

      if (n<0) {
        perror("Error receiving data");
      } else {
        printf("GOT %d BYTES\n",n);
        /* Got something, just send it back */
        sendto(sd,bufin,n,0,(struct sockaddr *)&remote,len);
      }
    }
}

/* server main routine */

int main() {
  int ld;
  struct sockaddr_in skaddr;
  int length;

  /* create a socket
     IP protocol family (PF_INET)
     UDP protocol (SOCK_DGRAM)
  */

  if ((ld = socket( PF_INET, SOCK_DGRAM, 0 )) < 0) {
    printf("Problem creating socket\n");
    exit(1);
  }

  /* establish our address
     address family is AF_INET
     our IP address is INADDR_ANY (any of our IP addresses)
     the port number is assigned by the kernel
  */

  skaddr.sin_family = AF_INET;
  skaddr.sin_addr.s_addr = htonl(INADDR_ANY);
  skaddr.sin_port = htons(0);

  if (bind(ld, (struct sockaddr *) &skaddr, sizeof(skaddr))<0) {
    printf("Problem binding\n");
    exit(0);
  }

  /* find out what port we were assigned and print it out */

  length = sizeof( skaddr );
  if (getsockname(ld, (struct sockaddr *) &skaddr, &length)<0) {
    printf("Error getsockname\n");
    exit(1);
  }

  /* port number's are network byte order, we have to convert to
     host byte order before printing !
  */
  printf("The server UDP port number is %d\n",ntohs(skaddr.sin_port));

  /* Go echo every datagram we get */
  echo(ld);
  return(0);
}

我是 Linux 新手，按照一些教程在我的 zedboard 上启动了 Linux。现在我必须制作一个在其上运行 udp echo 服务器的应用程序，我通过互联网获得了这个程序，现在我很困惑 arpa/inet.h netinet/in.h 是否已经在 Linux 中可用，还是我们必须制作它们？我应该如何以及在哪里提供 IP 地址和端口号？

答案1

不，你不必自己写，arpa/inet.h或者netinet/in.h- 它们由libc6-dev包裹：

$ dpkg -L libc6-dev | grep 'arpa\|netinet'
/usr/include/arpa
/usr/include/arpa/nameser_compat.h
/usr/include/arpa/telnet.h
/usr/include/arpa/tftp.h
/usr/include/arpa/inet.h
/usr/include/arpa/nameser.h
/usr/include/arpa/ftp.h
/usr/include/netinet
/usr/include/netinet/igmp.h
/usr/include/netinet/in_systm.h
/usr/include/netinet/ip.h
/usr/include/netinet/tcp.h
/usr/include/netinet/if_fddi.h
/usr/include/netinet/ip_icmp.h
/usr/include/netinet/ip6.h
/usr/include/netinet/ether.h
/usr/include/netinet/if_tr.h
/usr/include/netinet/udp.h
/usr/include/netinet/if_ether.h
/usr/include/netinet/icmp6.h
/usr/include/netinet/in.h

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