/***************************************
  $Header: /home/amb/wwwoffle/RCS/sockets.c 2.7 1998/04/06 18:11:59 amb Exp $

  WWWOFFLE - World Wide Web Offline Explorer - Version 2.1b.
  Socket manipulation routines.
  ******************/ /******************
  Written by Andrew M. Bishop

  This file Copyright 1996,97,98 Andrew M. Bishop
  It may be distributed under the GNU Public License, version 2, or
  any higher version.  See section COPYING of the GNU Public license
  for conditions under which this file may be redistributed.
  ***************************************/


#include <stdio.h>
#include <string.h>

#include <errno.h>
#include <unistd.h>

#include <netdb.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "errors.h"
#include "sockets.h"


/*++++++++++++++++++++++++++++++++++++++
  Opens a socket for a client.

  int OpenClientSocket Returns the socket file descriptor.

  char* host The name of the remote host.

  int port The socket number.
  ++++++++++++++++++++++++++++++++++++++*/

int OpenClientSocket(char* host, int port)
{
 int s;
 int retval,err=0;
 struct sockaddr_in server;
 struct hostent* hp;
 int retries=4;

 server.sin_family=AF_INET;
 server.sin_port=htons((unsigned short)port);

 hp=gethostbyname(host);
 if(!hp)
   {
    unsigned long int addr=inet_addr(host);
    if(addr!=-1)
       hp=gethostbyaddr((char*)addr,sizeof(addr),AF_INET);

    if(!hp)
      {errno=-1;PrintMessage(Warning,"Unknown host '%s' for server [%!s].",host);return(-1);}
   }
 memcpy((char*)&server.sin_addr,(char*)hp->h_addr,sizeof(server.sin_addr));

 do{
    s=socket(PF_INET,SOCK_STREAM,0);
    if(s==-1)
      {PrintMessage(Warning,"Cannot create client socket [%!s].");return(-1);}

    retval=connect(s,(struct sockaddr *)&server,sizeof(server));
    if(retval==-1)
      {
       err=errno;
       if(--retries && errno==ECONNREFUSED)
          PrintMessage(Inform,"Connect fail [%!s]; trying again.");
       else
          PrintMessage(Warning,"Connect fail [%!s].");
       close(s);
       s=-1;
       sleep(1);
      }
   }
 while(retval==-1 && retries && err==ECONNREFUSED);

 return(s);
}


/*++++++++++++++++++++++++++++++++++++++
  Opens a socket for a server.

  int OpenServerSocket Returns a socket to be a server.

  int port The port number to use.
  ++++++++++++++++++++++++++++++++++++++*/

int OpenServerSocket(int port)
{
 int s;
 int retval;
 struct sockaddr_in server;
 int reuse_addr=1;

 s=socket(PF_INET,SOCK_STREAM,0);
 if(s==-1)
   {PrintMessage(Warning,"Cannot create server socket [%!s].");return(-1);}

 setsockopt(s,SOL_SOCKET,SO_REUSEADDR,&reuse_addr,sizeof(reuse_addr));

 server.sin_family=AF_INET;
 server.sin_addr.s_addr=INADDR_ANY;
 server.sin_port=htons((unsigned int)port);

 retval=bind(s,(struct sockaddr*)&server,sizeof(server));
 if(retval==-1)
   {PrintMessage(Warning,"Failed to bind server socket [%!s].");return(-1);}

 listen(s,4);

 return(s);
}


/*++++++++++++++++++++++++++++++++++++++
  Waits for a connection on the socket.

  int AcceptConnect returns a socket with a remote connection on the end.

  int socket Specifies the socket to check for.
  ++++++++++++++++++++++++++++++++++++++*/

int AcceptConnect(int socket)
{
 int s;

 s=accept(socket,(struct sockaddr*)0,(int*)0);

 if(s==-1)
    PrintMessage(Warning,"Accept on server socket failed [%!s].");

 return(s);
}


/*++++++++++++++++++++++++++++++++++++++
  Determines the hostname and port number used for a socket on the other end.

  int SocketRemoteName Returns 0 on success and -1 on failure.

  int socket Specifies the socket to check.

  char **name Returns the hostname.

  char **ipname Returns the hostname as an IP address.

  int *port Returns the port number.
  ++++++++++++++++++++++++++++++++++++++*/

int SocketRemoteName(int socket,char **name,char **ipname,int *port)
{
 struct sockaddr_in server;
 int length=sizeof(server),retval;
 static char host[MAXHOSTNAMELEN],ip[16];
 struct hostent* hp=NULL;

 retval=getpeername(socket,(struct sockaddr*)&server,&length);
 if(retval==-1)
    PrintMessage(Warning,"Failed to get socket peername [%!s].");
 else
   {
    hp=gethostbyaddr((char*)&server.sin_addr,sizeof(server.sin_addr),AF_INET);
    if(hp)
       strcpy(host,hp->h_name);
    else
       strcpy(host,inet_ntoa(server.sin_addr));

    strcpy(ip,inet_ntoa(server.sin_addr));

    if(name)
       *name=host;
    if(ip)
       *ipname=ip;
    if(port)
       *port=ntohs(server.sin_port);
   }

 return(retval);
}


/*++++++++++++++++++++++++++++++++++++++
  Determines the hostname and port number used for a socket on this end.

  int SocketLocalName Returns 0 on success and -1 on failure.

  int socket Specifies the socket to check.

  char **name Returns the hostname.

  char **ipname Returns the hostname as an IP address.

  int *port Returns the port number.
  ++++++++++++++++++++++++++++++++++++++*/

int SocketLocalName(int socket,char **name,char **ipname,int *port)
{
 struct sockaddr_in server;
 int length=sizeof(server),retval;
 static char host[MAXHOSTNAMELEN],ip[16];
 struct hostent* hp=NULL;

 retval=getsockname(socket,(struct sockaddr*)&server,&length);
 if(retval==-1)
    PrintMessage(Warning,"Failed to get socket name [%!s].");
 else
   {
    hp=gethostbyaddr((char*)&server.sin_addr,sizeof(server.sin_addr),AF_INET);
    if(hp)
       strcpy(host,hp->h_name);
    else
       strcpy(host,inet_ntoa(server.sin_addr));

    strcpy(ip,inet_ntoa(server.sin_addr));

    if(name)
       *name=host;
    if(ipname)
       *ipname=ip;
    if(port)
       *port=ntohs(server.sin_port);
   }

 return(retval);
}


/*++++++++++++++++++++++++++++++++++++++
  Closes a previously opened socket.

  int CloseSocket Returns 0 on success, -1 on error.

  int socket The socket to close
  ++++++++++++++++++++++++++++++++++++++*/

int CloseSocket(int socket)
{
 int retval=close(socket);

 if(retval==-1)
    PrintMessage(Warning,"Socket close failed [%!s].");

 return(retval);
}


/*++++++++++++++++++++++++++++++++++++++
  Get the Fully Qualified Domain Name for the local host.

  char *GetFQDN Return the FQDN.
  ++++++++++++++++++++++++++++++++++++++*/

char *GetFQDN(void)
{
 static char fqdn[256],**h;
 struct hostent* hp;
 int type=hp->h_addrtype;
 int length=hp->h_length;
 char addr[sizeof(struct in_addr)];

 /* Try gethostname(). */

 if(gethostname(fqdn,255)==-1)
   {PrintMessage(Warning,"Failed to get hostname [%!s].");return(NULL);}

 if(strchr(fqdn,'.'))
    return(fqdn);

 /* Try gethostbyname(). */

 hp=gethostbyname(fqdn);
 if(!hp)
   {errno=-1;PrintMessage(Warning,"Can't get IP address for host [%!s].");return(NULL);}

 if(strchr(hp->h_name,'.'))
   {
    strcpy(fqdn,hp->h_name);
    return(fqdn);
   }

 for(h=hp->h_aliases;*h;h++)
    if(strchr(*h,'.'))
      {
       strcpy(fqdn,*h);
       return(fqdn);
      }

 /* Try gethostbyaddr(). */

 type=hp->h_addrtype;
 length=hp->h_length;
 memcpy(addr,(char*)hp->h_addr,sizeof(struct in_addr));

 hp=gethostbyaddr(addr,length,type);
 if(!hp)
   {errno=-1;PrintMessage(Warning,"Can't get hostname for IP address [%!s].");return(NULL);}

 if(strchr(hp->h_name,'.'))
   {
    strcpy(fqdn,hp->h_name);
    return(fqdn);
   }

 for(h=hp->h_aliases;*h;h++)
    if(strchr(*h,'.'))
      {
       strcpy(fqdn,*h);
       return(fqdn);
      }

 strcpy(fqdn,hp->h_name);

 return(fqdn);
}