path: root/comm/Address.cc

/*
 *	The Unix Channel
 *
 *	by Michel Beaudouin-Lafon
 *
 *	Copyright 1990-1993
 *	Laboratoire de Recherche en Informatique (LRI)
 *
 *	Addresses
 *
 *	$Id$
 *	$CurLog$
 */

#include "Address.h"
#include "error.h"

#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <memory.h>
#include <netdb.h>

/*?class UchAddress
This class is a virtual base class: no objects of this class are ever created.
It implements the Unix type \typ{^{struct sockaddr}}, used for creating sockets.
Addresses are used mainly as arguments of constructors for the class
\typ{UchSocket} and its derived classes.
All its member functions are virtual.
These functions exist for all the derived classes but are only described here.
An address can be valid or invalid, depending on the constructor being able to create the address or not.
There are currently two derived classes, for Unix domain addresses and Internet domain addresses.

The class \typ{^{pUchAddress}} implements smart pointers to addresses.
Smart pointers behave like pointers but they manage a reference count on the
pointed to objects for an automatic reclaim of dynamically allocated objects.
?*/

/*?
Construct an invalid address.
?*/
UchAddress :: UchAddress ()
: Valid (FALSE)
{
}

/*?nodoc?*/
UchAddress :: ~UchAddress ()
{
}

//	virtual functions for class address
//

/*?
Return one of \var{AF_UNSPEC}, \var{AF_UNIX} or \var{AF_INET}.
Other values may be defined if supported by the system.
?*/
int
UchAddress :: Family ()
{
	return AF_UNSPEC;
}

/*?nextdoc?*/
int
UchAddress :: Length ()
{
	return 0;
}

/*?
Return the address structure and its length.
\typ{^{SockAddr}} is a typedef for \typ{^{struct sockaddr}}.
?*/
SockAddr*
UchAddress :: GetSockAddr ()
{
	return 0;
}

/*?nodoc?*/
char*
UchAddress :: StrRepr (char* buf)
{
	strcpy (buf, "virtual address !");
	return buf;
}

#ifdef UNIX_SOCK

//	constructors for Unix addresses
//	a Unix domain address is just a filename
//	-> some problems: check for access, when to unlink it ?
//	to do : generate name from a template (for uniqueness)
//

/*?nodoc?*/
UchUnixAddress :: UchUnixAddress ()
: UchAddress ()
{
	// nothing
}

/*?
Create a Unix domain address associated to file \var{filename}.
The file is not unlinked when the address is destroyed;
it should be unlinked by the application whenever the last socket using this address is closed.
?*/
UchUnixAddress :: UchUnixAddress (const char* filename)
: UchAddress ()
{
	Addr.sun_family = AF_UNIX;
	strcpy (Addr.sun_path, filename);
	Valid = TRUE;	// should check access to file ???
			// unlink if already there ?
}

/*?nodoc?*/
UchUnixAddress :: ~UchUnixAddress ()
{
	// how to unlink the file ??
}

/*?nodoc?*/
int
UchUnixAddress :: Family ()
{
	return AF_UNIX;
}

/*?nodoc?*/
int
UchUnixAddress :: Length ()
{
	if (Valid)
		return (Addr.sun_path + strlen (Addr.sun_path)) - (char*) &Addr;
	return 0;
}

/*?nodoc?*/
SockAddr*
UchUnixAddress :: GetSockAddr ()
{
	return (SockAddr*) &Addr;
}

/*?nodoc?*/
char*
UchUnixAddress :: StrRepr (char* buf)
{
	sprintf (buf, "%s", Addr.sun_path);
	return buf;
}

#endif /* UNIX_SOCK */

//	constructors for inet addresses
//	inet address specified by:
//		hostname / port#	(ANY if hostname is NIL, LOOPBACK if hostname is "")
//		hostid / port#	(predefined hostids ANYADDR, ...)
//	todo:
//		hostname / service name	??
//
/*?nodoc?*/
UchInetAddress :: UchInetAddress ()
: UchAddress ()
{
	// nothing
}

/*?
Construct an inet address, from a hostname and a port number.
The address is valid only if the host is valid.
If \var{host} is the empty string, the loopback host is used;
if it is the nil pointer, the wildcard is used.
If the port number is 0, it will be allocated by the system.
?*/
UchInetAddress :: UchInetAddress (const char* name, sword port)
: UchAddress ()
{
	struct hostent	*host;
	
	if (name && *name) {
		host = gethostbyname (name);
		if (! host)
			return;
		memcpy (&Addr.sin_addr, host->h_addr, host->h_length);
	} else
		Addr.sin_addr.s_addr = name ? INADDR_LOOPBACK : INADDR_ANY;
	Addr.sin_family = AF_INET;
	Addr.sin_port = htons (port);
	Valid = TRUE;
}

/*?
Construct an inet address, from a host id (internet address) and a port number.
If the port number is 0, it is assigned by the system.
The host ids \var{^{ANYADDR}}, \var{^{LOOPBACK}} and \var{^{BROADCAST}} are predefined.
\var{ANYADDR} is used to receive messages from anywhere.
\var{LOOPBACK} is the local host address.
\var{BROADCAST} makes it possible to send data to all the hosts of a local area network.
?*/
UchInetAddress :: UchInetAddress (lword host, sword port)
: UchAddress ()
{
	Addr.sin_family = AF_INET;
	Addr.sin_port = htons (port);
	Addr.sin_addr.s_addr = host;
	Valid = TRUE;
}

/*?nodoc?*/
UchInetAddress :: ~UchInetAddress ()
{
}

/*?nodoc?*/
int
UchInetAddress :: Family ()
{
	return AF_INET;
}

/*?nodoc?*/
int
UchInetAddress :: Length ()
{
	return sizeof (Addr);
}

/*?nodoc?*/
SockAddr*
UchInetAddress :: GetSockAddr ()
{
	return (SockAddr*) &Addr;
}

/*?nodoc?*/
char*
UchInetAddress :: StrRepr (char* buf)
{
	struct hostent	*host;
	char		*hname;
	unsigned long	saddr;
	
	saddr = Addr.sin_addr.s_addr;
	host = gethostbyaddr ((char*) &saddr, sizeof (long), AF_INET);
	if (host)
		hname = host->h_name;
	else
		if (saddr == INADDR_ANY)
			hname = "ANY";
		else if (saddr == INADDR_LOOPBACK)
			hname = "LOOPBACK";
		else if (saddr == INADDR_BROADCAST)
			hname = "BROADCAST";
		else
			hname = "???";
	sprintf (buf, "%s::%d", hname, ntohs (Addr.sin_port));
	return buf;
}

/*?
This is a global function (static member of class \typ{UchAddress}).
It creates an object of a derived class of \typ{UchAddress} from a generic address
(thus is cannot be replaced by a constructor).
A generic address is the following union of address structures
(it is typically returned by system calls like \fun{recvfrom}):
\begin{ccode}
typedef union {
    struct sockaddr sa;        // default
    struct sockaddr_un su;     // Unix
    struct sockaddr_in si;     // inet
} GEN_ADDR;
\end{ccode}
?*/
UchAddress*
UchAddress :: Decode (GEN_ADDR* addr, int alen)
{
	switch (addr->sa.sa_family) {
#ifdef UNIX_SOCK
		case AF_UNIX :
			addr->su.sun_path [alen] = 0;
			return new UchUnixAddress (addr->su.sun_path);
#endif
		case AF_INET :
			return new UchInetAddress (addr->si.sin_addr.s_addr, addr->si.sin_port);
		
		default :
			return 0;
	}
}	

/*?
This is a global function (static member of class \typ{UchInetAddress}.
It returns the internet address of the local host.
This is different from the predefined address \var{LOOPBACK}:
\var{LOOPBACK} is the same constant on each machine, so that it cannot
be communicated across the network.
The value returned by \fun{LoopBack} is the unique internet address of the local host.
Thus it can be communicated to another host across the network.
?*/
lword
UchInetAddress :: LoopBack ()
{
	static	lword	loopback = 0;
	
	if (loopback)
		return loopback;
	
	struct hostent	*host;
	char		name [128];
	
	gethostname (name, sizeof (name));
	host = gethostbyname (name);
	if (! host) {
		Error (ErrFatal, "address", "cannot get address of local host");
		return 0;
	}
	return loopback = * ((lword *) host->h_addr);
}

#ifdef DOC
// fake entries for inline functions

/*?
Return TRUE if the address is valid.
?*/
bool 
UchAddress :: IsValid ()
{}

/*?
Return the host number of the address.
?*/
lword
UchInetAddress :: Host ()
{}

/*?
Return the port number of the address.
?*/
sword
UchInetAddress :: Port ()
{}

#endif /* DOC */