[X25]: Fast select with no restriction on response
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>
diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c
index e17d84a..04bec04 100644
--- a/net/x25/af_x25.c
+++ b/net/x25/af_x25.c
@@ -31,6 +31,8 @@
* x25_proc.c, using seq_file
* 2005-04-02 Shaun Pereira Selective sub address matching
* with call user data
+ * 2005-04-15 Shaun Pereira Fast select with no restriction on
+ * response
*/
#include <linux/config.h>
@@ -502,6 +504,8 @@
x25->t2 = sysctl_x25_ack_holdback_timeout;
x25->state = X25_STATE_0;
x25->cudmatchlength = 0;
+ x25->accptapprv = X25_DENY_ACCPT_APPRV; /* normally no cud */
+ /* on call accept */
x25->facilities.winsize_in = X25_DEFAULT_WINDOW_SIZE;
x25->facilities.winsize_out = X25_DEFAULT_WINDOW_SIZE;
@@ -551,6 +555,7 @@
x25->facilities = ox25->facilities;
x25->qbitincl = ox25->qbitincl;
x25->cudmatchlength = ox25->cudmatchlength;
+ x25->accptapprv = ox25->accptapprv;
x25_init_timers(sk);
out:
@@ -900,9 +905,11 @@
makex25->vc_facil_mask &= ~X25_MASK_REVERSE;
makex25->cudmatchlength = x25_sk(sk)->cudmatchlength;
- x25_write_internal(make, X25_CALL_ACCEPTED);
-
- makex25->state = X25_STATE_3;
+ /* Normally all calls are accepted immediatly */
+ if(makex25->accptapprv & X25_DENY_ACCPT_APPRV) {
+ x25_write_internal(make, X25_CALL_ACCEPTED);
+ makex25->state = X25_STATE_3;
+ }
/*
* Incoming Call User Data.
@@ -1294,7 +1301,8 @@
if (facilities.throughput < 0x03 ||
facilities.throughput > 0xDD)
break;
- if (facilities.reverse && facilities.reverse != 1)
+ if (facilities.reverse &&
+ (facilities.reverse | 0x81)!= 0x81)
break;
x25->facilities = facilities;
rc = 0;
@@ -1348,6 +1356,27 @@
break;
}
+ case SIOCX25CALLACCPTAPPRV: {
+ rc = -EINVAL;
+ if (sk->sk_state != TCP_CLOSE)
+ break;
+ x25->accptapprv = X25_ALLOW_ACCPT_APPRV;
+ rc = 0;
+ break;
+ }
+
+ case SIOCX25SENDCALLACCPT: {
+ rc = -EINVAL;
+ if (sk->sk_state != TCP_ESTABLISHED)
+ break;
+ if (x25->accptapprv) /* must call accptapprv above */
+ break;
+ x25_write_internal(sk, X25_CALL_ACCEPTED);
+ x25->state = X25_STATE_3;
+ rc = 0;
+ break;
+ }
+
default:
rc = dev_ioctl(cmd, argp);
break;