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#ident "$Id: socket.c,v 4.2 2014/01/28 13:44:14 gert Exp $"
/* socket.c - part of mgetty+sendfax
*
* open TCP/IP sockets to talk to remote fax modems (sendfax)
*
* $Log: socket.c,v $
* Revision 4.2 2014/01/28 13:44:14 gert
* log_init_path() with infix => last 4 digits of "remote tty" (R104, etc.)
*
* set SIGPIPE to SIG_IGN - if the remote end of the socket is closed
* unexpectedly, write() might return an error, or raise SIGPIPE -> code
* handles errors, so ignore SIGPIPE.
*
* Revision 4.1 2014/01/28 13:15:50 gert
* Basic "open TCP/IP socket to remote machine" implementation
* (name of remote + tcp portnumber are magick'ed out of ttyRI<n><mm>)
*
*/
#include "policy.h"
#ifdef FAX_SEND_SOCKETS
#include <stdio.h>
#include "syslibs.h"
#include <unistd.h>
#include <signal.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <netdb.h>
#include <netinet/in.h>
#include "mgetty.h"
extern boolean verbose; /* sendfax.c */
extern char * Device; /* sendfax.c */
/* sendfax' logic for "what is a remote tty" is currently hardwired
* (to be able to actually get something in place, without rewriting
* most of the config file infrastructure) - if the tty name matches
* "ttyRInmm", it will be treated as "connect to 'modemserver<n>' on
* port 50000+<mm>, raw socket, no modem control / telnet escapes"
*
* This might get enhanced later on with modem control (RFC 2217) or
* configfile-settable ports. For now, we start with *this*.
*
* return value: -1 -> fail, >= 0 -> socket FD
*/
int connect_to_remote_tty _P1( (fax_tty), char * fax_tty )
{
int line, r;
int sock = -1;
char hostname[20];
char servname[10];
struct addrinfo hints;
struct addrinfo * res0, *res;
/* ttyRI<n> */
if ( !isdigit( (int) fax_tty[5] ) )
{
lprintf( L_ERROR, "invalid tty format: '%s' - 6th char must be 0..9", fax_tty );
return -1;
}
sprintf( hostname, "modemserver%c", fax_tty[5] );
line = atoi( &fax_tty[6] );
if ( line < 1 || line > 999 )
{
lprintf( L_ERROR, "invalid tty format: '%s' - port number must be 01..999", fax_tty );
return -1;
}
sprintf( servname, "%d", line + 50000 );
lprintf( L_MESG, "trying '%s' on port %s...", hostname, servname );
if (verbose) putchar( '\n' );
memset(&hints, 0, sizeof(hints));
hints.ai_family = PF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_NUMERICSERV;
r = getaddrinfo( hostname, servname, &hints, &res0 );
if ( r != 0 )
{
errno = 0;
lprintf( L_ERROR, "getaddrinfo(%s) failed: %s", hostname, gai_strerror(r));
return -1;
}
/* connect loop from "man getaddrinfo"... */
for ( res = res0; res != NULL; res = res->ai_next )
{
char nbuf[NI_MAXHOST];
r = getnameinfo( res->ai_addr, res->ai_addrlen, nbuf, sizeof(nbuf)-1,
NULL, 0, NI_NUMERICHOST );
if ( r != 0 )
{ lprintf( L_ERROR, "error in getnameinfo (canthappen!)" ); continue; }
if ( verbose )
{ printf( " connecting to %s... ", nbuf ); fflush(stdout); }
sock = socket( res->ai_family, res->ai_socktype, res->ai_protocol );
if ( sock < 0 )
{ lprintf( L_ERROR, "error in socket()" ); continue; }
if ( connect( sock, res->ai_addr, res->ai_addrlen ) < 0 )
{
int save_errno = errno;
lprintf( L_ERROR, "error in connect(%s:%s)", nbuf, servname );
if ( verbose )
printf( "connect failed: %s\n", strerror(save_errno) );
close(sock);
sock = -1;
continue;
}
if ( verbose ) printf( "OK\n" );
lprintf( L_MESG, "connection to '%s':'%s' succeeded, sock=%d",
nbuf, servname, sock );
break;
}
freeaddrinfo(res0);
if ( sock >= 0 ) /* success? */
{
/* make device name externally visible (faxrec())
*/
Device = safe_strdup( fax_tty );
log_init_paths( NULL, NULL, &fax_tty[ strlen(fax_tty)-4 ] );
/* The rest of the code assumes that a tty fd might return an
* error write()ing to it, but not that it might go away completely
* and give us an SIGPIPE. Ignore. Sue me.
*/
signal( SIGPIPE, SIG_IGN );
}
/* sock is either a connected socket now, or "-1" -> pass up */
return sock;
}
#endif /* FAX_SEND_SOCKETS */
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