《UNIX 网络编程》 第三章课后习题第三题

#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>

/**
具体的转换过程，不做详细注释，有更好的实现方式
**/
int
inet_pton_loose(int family,const char *strptr,void *addrptr)
{
int i = 0;

if(inet_pton(family,strptr,addrptr) == 0){

struct in_addr  v4addr;

if(inet_aton(strptr,&v4addr)    == 1){

if(family == AF_INET){

memcpy(addrptr,(void *)&v4addr,sizeof(struct in_addr));
return 1;
}

if(family == AF_INET6){

struct in6_addr v6addr;

for(i=0;i<16;i++){

if(i<10)
v6addr.s6_addr[i] = 0;
if(i >= 10 && i < 12)
v6addr.s6_addr[i] = 0xf;
if(i >= 12 )
v6addr.s6_addr[i] = htonl(v4addr.s_addr)>>(16-i-1)*8;

}
memcpy(addrptr,(void *)&v6addr,sizeof(struct in6_addr));
return 1;
}
}
return 0;
}
return 1;
}

/**
获取输入，辨别是IPv4 还是IPv6 并做相应的处，理完成后输出用户的输入。没有添加错误处理。
**/
int
main(int argc,char **argv)
{
struct in_addr IPv4addr;
struct in6_addr IPv6addr;

const u_char *strptr;
const char *AddrFlag4 = "AF_INET";
const char *AddrFlag6 = "AF_INET6";

if(strcmp(AddrFlag4,argv[1]) == 0){

if(inet_pton_loose(AF_INET,argv[2],(void *)&IPv4addr) == 1){

strptr = (u_char *)&IPv4addr;
printf("%s---%d.%d.%d.%d\n",argv[1],strptr[0],strptr[1],strptr[2],strptr[3]);
return 1;
}

}

if(strcmp(AddrFlag6,argv[1]) == 0){

if(inet_pton_loose(AF_INET6,argv[2],(void *)&IPv6addr)  == 1){

strptr = (u_char *)&IPv6addr;
printf("%s---%d%d:%d%d:%d%d:%d%d:%d%d:%x%x:%d.%d.%d.%d\n",argv[1],strptr[0],strptr[1],
strptr[2],strptr[3],strptr[4],strptr[5],strptr[6],strptr[7],strptr[8],strptr[9]
,strptr[10],strptr[11],strptr[12],strptr[13],strptr[14],strptr[15]);

return 1;
}
}

return 1;
}

#include "unp.h"

in_addr_t inet_pton_loose(int family, const char *strptr,void *addrptr)

{

struct in_addr *ap = (struct in_addr *)addrptr;

int result = 0;

if((family == AF_INET) && (inet_pton(family,strptr,addrptr) == 0))

{

printf("the net protocol is IPv4 str is %s\n",strptr);

result = inet_aton(strptr,ap);

printf("result is %d\n",result);

if(result)

return ap->s_addr;

else

return 0;

}

else if ((family == AF_INET6) && (inet_pton(family,strptr,addrptr) == 0))

{

printf("the net protocol is IPv6\n");

result = inet_aton(strptr,ap);

printf("result is %d\n",result);

if(result)

{

return ap->s_addr;

}

else

return 0;

}

return 0;

}

int main (int argc, char **argv)

{

//if argv[1] is zero, means AF_INET type, 1 for AF_INET6 type

char s[20];

struct in_addr addr;

in_addr_t addr_result = 0;

if(argc < 2)

{

printf("usage: ./mytest <fa> <addr>\n");

return 1;

}

bzero(&addr,sizeof(struct in_addr));

memset(s,0,sizeof(s));

strcpy(s,argv[2]);

if(atoi(argv[1]) == 0)

{

printf("the net protocol is IPv4\n");

addr_result = inet_pton_loose(AF_INET,s,(void *)&addr);

printf("addr_result is %x\n",addr_result);

}

else if(atoi(argv[1]) == 1)

{

printf("the net protocol is IPv6\n");

addr_result = inet_pton_loose(AF_INET6,s,(void *)&addr);

printf("addr_result is %x\n",addr_result);

}

return 0;

}