Error: failed to create socket

[Bill Fink]

On Mon, 8 Sep 2003, I wrote:

> On Mon, 08 Sep 2003, Charles Trois wrote:
> 
> > le 8/09/03 20:01, yellowdog-general-request@lists.terrasoftsolutions.com à
> > yellowdog-general-request@lists.terrasoftsolutions.com a écrit :
> > 
> > > Message: 12
> > > Date: Mon, 08 Sep 2003 13:36:02 +0200
> > > Subject: Re:  Error: failed to create socket
> > > From: Charles Trois <charles.trois@wanadoo.fr>
> > > To: <yellowdog-general@lists.terrasoftsolutions.com>
> > > Cc: Bill Fink <billfink@mindspring.com>
> > > Reply-To: yellowdog-general@lists.terrasoftsolutions.com
> > > 
> > > le 7/09/03 20:01, yellowdog-general-request@lists.terrasoftsolutions.com =E0
> > > yellowdog-general-request@lists.terrasoftsolutions.com a =E9crit=A0:
> > > 
> > >> =20
> > >> Message: 7
> > >> Date: Sun, 07 Sep 2003 18:50:40 +0200
> > >> Subject:Re:  Error: failed to create socket
> > >> From: Charles Trois <charles.trois@wanadoo.fr>
> > >> To: <yellowdog-general@lists.terrasoftsolutions.com>
> > >> Cc: Bill Fink <billfink@mindspring.com>
> > >> Reply-To: yellowdog-general@lists.terrasoftsolutions.com
> > >> =20
> > >> le 6/09/03 19:25, yellowdog-general-request@lists.terrasoftsolutions.com =
> > > =3DE0
> > >> yellowdog-general-request@lists.terrasoftsolutions.com a =3DE9crit=3DA0:
> > >> =20
> > >>> Hi Charles,
> > >>> =3D20
> > >>> This problem sounded familiar.  I believe I've encountered something
> > >>> similar with a different application.
> > >>> =3D20
> > >>> I downloaded speedbundle-1.0.tar.gz, unpacked it and searched for
> > >>> the string "failed to create socket":
> > >>> =3D20
> > >>> gwiz% grep -r 'failed to create socket' speedbundle-1.0
> > >>> speedbundle-1.0/ppp/pppd/plugins/pppoatm.c:             fatal("failed to
> > >>> create socket: %m");
> > >>> =3D20
> > >>> I then edited the pppoatm.c file and searched again for the string
> > >>> "failed to create socket".  This was the relevant section of code:
> > >>> =3D20
> > >>> fd =3D3D socket(AF_ATMPVC, SOCK_DGRAM, 0);
> > >>> if (fd < 0)
> > >>> fatal("failed to create socket: %m");
> > >>> =3D20
> > >>> The last argument to socket() is the protocol.  It used to be OK to
> > >>> just pass a 0 for the protocol argument, but the kernel is now more
> > >>> strict about this.  A value of 0 for protocol is actually PF_UNSPEC
> > >>> or protocol family unspecified.
> > >>> =3D20
> > >>> I believe it should be sufficient to just change the protocol argument
> > >>> of 0 to PF_ATMPVC.
> > >>> =3D20
> > >> =20
> > >> Alas no; still the same error. Any further ideas?
> > > 
> > > Hello Bill,=20
> > > 
> > > I think I have made a little progress.
> > > 
> > > I learned from man 7 ip that the function
> > > socket(AF_ATMPVC, SOCK_DGRAM, protocol) creates a udp_socket, for which the
> > > only valid values of protocol are 0 and IPPROTO_UDP.
> > > 
> > > As I know that 0 doesn't work, I tried the other value; but then the
> > > compiler gives the error "undeclared".
> > > 
> > > Do you think that the solution lies there? If so, where and how could I
> > > introduce a declaration of IPPROTO_UDP?
> > 
> > I would like to add this to my previous message above:
> > 
> > I have gone a further step, in that I have found that IPPROTO_UDP is in
> > /usr/include/netinet/inet.h.
> > 
> > I therefore added in pppoatm.c the line
> > 
> > #include <netinet/in.h>
> > 
> > and I got a clean compilation.
> > 
> > However, when running "pppd call speedtch", I got again the error "failed to
> > create socket: Address family not supported by protocol".
> > 
> > I am quite puzzled and wondering what is compatible with what.
> > 
> > Does anyone know that? Might I have to touch up the kernel?
> 
> You definitely don't want to do that.  IPPROTO_UDP is an IP protocol
> within the IP (INET) protocol family (PF_INET), and is not meaningful
> for the PF_ATMPVC protocol family.
> 
> My apologies as I misread the socket man page earlier.  The original
> code with the value of 0 for the protocol argument to the socket()
> call was probably fine.  It's sounding more like there's something
> missing in your kernel that provides the PF_ATMPVC protocol family.
> 
> I just found this in /usr/include/atm.h that defines the possible
> values for the protocol argument to the socket() call for ATM:
> 
> /* "protcol" values for the socket system call */
> #define ATM_NO_AAL      0               /* AAL not specified */
> #define ATM_AAL0        13              /* "raw" ATM cells */
> #define ATM_AAL1        1               /* AAL1 (CBR) */
> #define ATM_AAL2        2               /* AAL2 (VBR) */
> #define ATM_AAL34       3               /* AAL3/4 (data) */
> #define ATM_AAL5        5               /* AAL5 (data) */
> 
> Since I'm not sure what ATM Adaptation Layer (AAL) is used by PPPOATM,
> I can't really say what the correct value for the protocol argument
> should be (IP uses AAL5).
> 
> 						-Bill

A clarification:  A value of 0 for the protocol argument to the socket()
call may or may not be OK, depending on whether or not the kernel is
OK with not explicitly specifying what AAL to use.