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[X25]: Fast select with no restriction on response

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This patch is a follow up to patch 1 regarding "Selective Sub Address
matching with call user data".  It allows use of the Fast-Select-Acceptance
optional user facility for X.25.

This patch just implements fast select with no restriction on response
(NRR).  What this means (according to ITU-T Recomendation 10/96 section
6.16) is that if in an incoming call packet, the relevant facility bits are
set for fast-select-NRR, then the called DTE can issue a direct response to
the incoming packet using a call-accepted packet that contains
call-user-data.  This patch allows such a response.  

The called DTE can also respond with a clear-request packet that contains
call-user-data.  However, this feature is currently not implemented by the
patch.

How is Fast Select Acceptance used?
By default, the system does not allow fast select acceptance (as before).
To enable a response to fast select acceptance,  
After a listen socket in created and bound as follows
	socket(AF_X25, SOCK_SEQPACKET, 0);
	bind(call_soc, (struct sockaddr *)&locl_addr, sizeof(locl_addr));
but before a listen system call is made, the following ioctl should be used.
	ioctl(call_soc,SIOCX25CALLACCPTAPPRV);
Now the listen system call can be made
	listen(call_soc, 4);
After this, an incoming-call packet will be accepted, but no call-accepted 
packet will be sent back until the following system call is made on the socket
that accepts the call
	ioctl(vc_soc,SIOCX25SENDCALLACCPT);
The network (or cisco xot router used for testing here) will allow the 
application server's call-user-data in the call-accepted packet, 
provided the call-request was made with Fast-select NRR.

Signed-off-by: Shaun Pereira <spereira@tusc.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Shaun Pereira
2005-06-22 22:16:17 -07:00
committed by David S. Miller
parent cb65d506c3
commit ebc3f64b86
5 changed files with 86 additions and 16 deletions
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6
include/net/x25.h
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@@ -79,6 +79,8 @@ enum {
#define X25_DEFAULT_PACKET_SIZE X25_PS128 /* Default Packet Size */
#define X25_DEFAULT_THROUGHPUT 0x0A /* Deafult Throughput */
#define X25_DEFAULT_REVERSE 0x00 /* Default Reverse Charging */
#define X25_DENY_ACCPT_APPRV 0x01 /* Default value */
#define X25_ALLOW_ACCPT_APPRV 0x00 /* Control enabled */
#define X25_SMODULUS 8
#define X25_EMODULUS 128
@@ -94,7 +96,7 @@ enum {
#define X25_FAC_CLASS_C 0x80
#define X25_FAC_CLASS_D 0xC0
#define X25_FAC_REVERSE 0x01
#define X25_FAC_REVERSE 0x01 /* also fast select */
#define X25_FAC_THROUGHPUT 0x02
#define X25_FAC_PACKET_SIZE 0x42
#define X25_FAC_WINDOW_SIZE 0x43
@@ -135,7 +137,7 @@ struct x25_sock {
struct x25_address source_addr, dest_addr;
struct x25_neigh *neighbour;
unsigned int lci, cudmatchlength;
unsigned char state, condition, qbitincl, intflag;
unsigned char state, condition, qbitincl, intflag, accptapprv;
unsigned short vs, vr, va, vl;
unsigned long t2, t21, t22, t23;
unsigned short fraglen;