sock_ntop() user def function for conversion

/*
sock_ntop() user def function for conversion
SOURCE CODE FOR AF_INET  */

char *SOCK_ntop(const struct sock_addr *addr *sa, socklen_t slen)
{
char portstr[7];
static char str[128]; /* unix domain is largest */
switch(sa->sa.family)
{
case AF_INET:{ struct sockaddr_in *sin=(struct sockaddr_in*)sa;
if(inet_ntop(AF_INET, &SIN->sin_addr,str,sizeof(st)==NULL)
return NULL;
if(ntoh s(sin->sin_port)!=0){
sprintf(portstr, sizeof(portstr),"%d",ntoh s(sin->sin_port);
strcat(str,strport);}
return str;
}