[PATCH 2/2 - 2.6.11.7] x25: Fast select with no restriction onresponse

From: Shaun Pereira
Date: Tue Apr 19 2005 - 22:20:45 EST

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Hi
This patch is a follow up to the 'resend' version of the "Selective Sub Address
matching with call user data" patch. 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 Accetance 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.

diff -uprN -X dontdiff linux-2.6.11.7-vanilla/include/linux/x25.h linux-2.6.11.7/include/linux/x25.h
--- linux-2.6.11.7-vanilla/include/linux/x25.h 2005-04-20 12:48:50.000000000 +1000
+++ linux-2.6.11.7/include/linux/x25.h 2005-04-20 12:49:40.000000000 +1000
@@ -19,6 +19,8 @@
#define SIOCX25SCALLUSERDATA (SIOCPROTOPRIVATE + 5)
#define SIOCX25GCAUSEDIAG (SIOCPROTOPRIVATE + 6)
#define SIOCX25SCUDMATCHLEN (SIOCPROTOPRIVATE + 7)
+#define SIOCX25CALLACCPTAPPRV (SIOCPROTOPRIVATE + 8)
+#define SIOCX25SENDCALLACCPT (SIOCPROTOPRIVATE + 9)

/*
* Values for {get,set}sockopt.
diff -uprN -X dontdiff linux-2.6.11.7-vanilla/include/net/x25.h linux-2.6.11.7/include/net/x25.h
--- linux-2.6.11.7-vanilla/include/net/x25.h 2005-04-20 12:48:50.000000000 +1000
+++ linux-2.6.11.7/include/net/x25.h 2005-04-20 12:49:40.000000000 +1000
@@ -78,6 +78,8 @@ 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
@@ -93,7 +95,7 @@ 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
@@ -133,7 +135,7 @@ struct x25_opt {
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;
diff -uprN -X dontdiff linux-2.6.11.7-vanilla/net/x25/af_x25.c linux-2.6.11.7/net/x25/af_x25.c
--- linux-2.6.11.7-vanilla/net/x25/af_x25.c 2005-04-20 12:48:50.000000000 +1000
+++ linux-2.6.11.7/net/x25/af_x25.c 2005-04-20 12:49:40.000000000 +1000
@@ -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>
@@ -509,6 +511,8 @@ static int x25_create(struct socket *soc
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;
@@ -554,6 +558,7 @@ static struct sock *x25_make_new(struct
x25->facilities = ox25->facilities;
x25->qbitincl = ox25->qbitincl;
x25->cudmatchlength = ox25->cudmatchlength;
+ x25->accptapprv = ox25->accptapprv;

x25_init_timers(sk);
out:
@@ -903,9 +908,11 @@ int x25_rx_call_request(struct sk_buff *
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.
@@ -1297,7 +1304,8 @@ static int x25_ioctl(struct socket *sock
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;
@@ -1351,6 +1359,27 @@ static int x25_ioctl(struct socket *sock
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;
diff -uprN -X dontdiff linux-2.6.11.7-vanilla/net/x25/x25_facilities.c linux-2.6.11.7/net/x25/x25_facilities.c
--- linux-2.6.11.7-vanilla/net/x25/x25_facilities.c 2005-04-08 04:57:43.000000000 +1000
+++ linux-2.6.11.7/net/x25/x25_facilities.c 2005-04-20 12:49:40.000000000 +1000
@@ -17,6 +17,8 @@
* X.25 001 Split from x25_subr.c
* mar/20/00 Daniela Squassoni Disabling/enabling of facilities
* negotiation.
+ * apr/14/05 Shaun Pereira - Allow fast select with no restriction
+ * on response.
*/

#include <linux/kernel.h>
@@ -42,10 +44,32 @@ int x25_parse_facilities(struct sk_buff
switch (*p & X25_FAC_CLASS_MASK) {
case X25_FAC_CLASS_A:
switch (*p) {
- case X25_FAC_REVERSE:
- facilities->reverse = p[1] & 0x01;
- *vc_fac_mask |= X25_MASK_REVERSE;
- break;
+ case X25_FAC_REVERSE:
+ if((p[1] & 0x81) == 0x81) {
+ facilities->reverse = p[1] & 0x81;
+ *vc_fac_mask |= X25_MASK_REVERSE;
+ break;
+ }
+
+ if((p[1] & 0x01) == 0x01) {
+ facilities->reverse = p[1] & 0x01;
+ *vc_fac_mask |= X25_MASK_REVERSE;
+ break;
+ }
+
+ if((p[1] & 0x80) == 0x80) {
+ facilities->reverse = p[1] & 0x80;
+ *vc_fac_mask |= X25_MASK_REVERSE;
+ break;
+ }
+
+ if(p[1] == 0x00) {
+ facilities->reverse
+ = X25_DEFAULT_REVERSE;
+ *vc_fac_mask |= X25_MASK_REVERSE;
+ break;
+ }
+
case X25_FAC_THROUGHPUT:
facilities->throughput = p[1];
*vc_fac_mask |= X25_MASK_THROUGHPUT;
@@ -122,7 +146,7 @@ int x25_create_facilities(unsigned char

if (facilities->reverse && (facil_mask & X25_MASK_REVERSE)) {
*p++ = X25_FAC_REVERSE;
- *p++ = !!facilities->reverse;
+ *p++ = facilities->reverse;
}

if (facilities->throughput && (facil_mask & X25_MASK_THROUGHPUT)) {
@@ -171,7 +195,7 @@ int x25_negotiate_facilities(struct sk_b
/*
* They want reverse charging, we won't accept it.
*/
- if (theirs.reverse && ours->reverse) {
+ if ((theirs.reverse & 0x01 ) && (ours->reverse & 0x01)) {
SOCK_DEBUG(sk, "X.25: rejecting reverse charging request");
return -1;
}
diff -uprN -X dontdiff linux-2.6.11.7-vanilla/net/x25/x25_subr.c linux-2.6.11.7/net/x25/x25_subr.c
--- linux-2.6.11.7-vanilla/net/x25/x25_subr.c 2005-04-20 12:48:50.000000000 +1000
+++ linux-2.6.11.7/net/x25/x25_subr.c 2005-04-20 12:49:40.000000000 +1000
@@ -19,6 +19,8 @@
* mar/20/00 Daniela Squassoni Disabling/enabling of facilities
* negotiation.
* jun/24/01 Arnaldo C. Melo use skb_queue_purge, cleanups
+ * apr/04/15 Shaun Pereira Fast select with no
+ * restriction on response.
*/

#include <linux/kernel.h>
@@ -127,8 +129,12 @@ void x25_write_internal(struct sock *sk,
len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN +
X25_MAX_CUD_LEN;
break;
- case X25_CALL_ACCEPTED:
- len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
+ case X25_CALL_ACCEPTED: /* fast sel with no restr on resp */
+ if(x25->facilities.reverse & 0x80) {
+ len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
+ } else {
+ len += 1 + X25_MAX_FAC_LEN;
+ }
break;
case X25_CLEAR_REQUEST:
case X25_RESET_REQUEST:
@@ -203,9 +209,16 @@ void x25_write_internal(struct sock *sk,
x25->vc_facil_mask);
dptr = skb_put(skb, len);
memcpy(dptr, facilities, len);
- dptr = skb_put(skb, x25->calluserdata.cudlength);
- memcpy(dptr, x25->calluserdata.cuddata,
- x25->calluserdata.cudlength);
+
+ /* fast select with no restriction on response
+ allows call user data. Userland must
+ ensure it is ours and not theirs */
+ if(x25->facilities.reverse & 0x80) {
+ dptr = skb_put(skb,
+ x25->calluserdata.cudlength);
+ memcpy(dptr, x25->calluserdata.cuddata,
+ x25->calluserdata.cudlength);
+ }
x25->calluserdata.cudlength = 0;
break;

-
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Next message: James Cleverdon: "Re: easy softball jiffies quest(ion)"
Previous message: Paul Jackson: "Re: [PATCH 1/4] ppc64: rename arch/ppc64/kernel/pSeries_pci.c"
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