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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>
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Shaun Pereira authored and David S. Miller committed Jun 23, 2005
1 parent cb65d50 commit ebc3f64
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Showing 5 changed files with 86 additions and 16 deletions.
2 changes: 2 additions & 0 deletions include/linux/x25.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand Down
6 changes: 4 additions & 2 deletions include/net/x25.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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
Expand Down Expand Up @@ -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;
Expand Down
37 changes: 33 additions & 4 deletions net/x25/af_x25.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand Down Expand Up @@ -502,6 +504,8 @@ static int x25_create(struct socket *sock, int protocol)
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;
Expand Down Expand Up @@ -551,6 +555,7 @@ static struct sock *x25_make_new(struct sock *osk)
x25->facilities = ox25->facilities;
x25->qbitincl = ox25->qbitincl;
x25->cudmatchlength = ox25->cudmatchlength;
x25->accptapprv = ox25->accptapprv;

x25_init_timers(sk);
out:
Expand Down Expand Up @@ -900,9 +905,11 @@ int x25_rx_call_request(struct sk_buff *skb, struct x25_neigh *nb,
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.
Expand Down Expand Up @@ -1294,7 +1301,8 @@ static int x25_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
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;
Expand Down Expand Up @@ -1348,6 +1356,27 @@ static int x25_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
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;
Expand Down
34 changes: 29 additions & 5 deletions net/x25/x25_facilities.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand All @@ -43,9 +45,31 @@ int x25_parse_facilities(struct sk_buff *skb,
case X25_FAC_CLASS_A:
switch (*p) {
case X25_FAC_REVERSE:
facilities->reverse = p[1] & 0x01;
*vc_fac_mask |= X25_MASK_REVERSE;
break;
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;
Expand Down Expand Up @@ -122,7 +146,7 @@ int x25_create_facilities(unsigned char *buffer,

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)) {
Expand Down Expand Up @@ -171,7 +195,7 @@ int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk,
/*
* 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;
}
Expand Down
23 changes: 18 additions & 5 deletions net/x25/x25_subr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand Down Expand Up @@ -127,8 +129,12 @@ void x25_write_internal(struct sock *sk, int frametype)
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:
Expand Down Expand Up @@ -203,9 +209,16 @@ void x25_write_internal(struct sock *sk, int frametype)
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;

Expand Down

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