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linux/net/x25/x25_subr.c
Shaun Pereira a64b7b936d [X25]: allow ITU-T DTE facilities for x25 
Allows use of the optional user facility to insert ITU-T
(http://www.itu.int/ITU-T/) specified DTE facilities in call set-up x25
packets.  This feature is optional; no facilities will be added if the ioctl
is not used, and call setup packet remains the same as before.

If the ioctls provided by the patch are used, then a facility marker will be
added to the x25 packet header so that the called dte address extension
facility can be differentiated from other types of facilities (as described in
the ITU-T X.25 recommendation) that are also allowed in the x25 packet header.

Facility markers are made up of two octets, and may be present in the x25
packet headers of call-request, incoming call, call accepted, clear request,
and clear indication packets.  The first of the two octets represents the
facility code field and is set to zero by this patch.  The second octet of the
marker represents the facility parameter field and is set to 0x0F because the
marker will be inserted before ITU-T type DTE facilities.

Since according to ITU-T X.25 Recommendation X.25(10/96)- 7.1 "All networks
will support the facility markers with a facility parameter field set to all
ones or to 00001111", therefore this patch should work with all x.25 networks.

While there are many ITU-T DTE facilities, this patch implements only the
called and calling address extension, with placeholders in the
x25_dte_facilities structure for the rest of the facilities.

Testing:

This patch was tested using a cisco xot router connected on its serial ports
to an X.25 network, and on its lan ports to a host running an xotd daemon.

It is also possible to test this patch using an xotd daemon and an x25tap
patch, where the xotd daemons work back-to-back without actually using an x.25
network.  See www.fyonne.net for details on how to do this.

Signed-off-by: Shaun Pereira <spereira@tusc.com.au>
Acked-by: Andrew Hendry <ahendry@tusc.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-22 00:01:31 -08:00

372 lines
9.1 KiB
C
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/*
* X.25 Packet Layer release 002
*
* This is ALPHA test software. This code may break your machine,
* randomly fail to work with new releases, misbehave and/or generally
* screw up. It might even work.
*
* This code REQUIRES 2.1.15 or higher
*
* This module:
* This module is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* History
* X.25 001 Jonathan Naylor Started coding.
* X.25 002 Jonathan Naylor Centralised disconnection processing.
* 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>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/x25.h>
/*
* This routine purges all of the queues of frames.
*/
void x25_clear_queues(struct sock *sk)
{
struct x25_sock *x25 = x25_sk(sk);
skb_queue_purge(&sk->sk_write_queue);
skb_queue_purge(&x25->ack_queue);
skb_queue_purge(&x25->interrupt_in_queue);
skb_queue_purge(&x25->interrupt_out_queue);
skb_queue_purge(&x25->fragment_queue);
}
/*
* This routine purges the input queue of those frames that have been
* acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
* SDL diagram.
*/
void x25_frames_acked(struct sock *sk, unsigned short nr)
{
struct sk_buff *skb;
struct x25_sock *x25 = x25_sk(sk);
int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
/*
* Remove all the ack-ed frames from the ack queue.
*/
if (x25->va != nr)
while (skb_peek(&x25->ack_queue) && x25->va != nr) {
skb = skb_dequeue(&x25->ack_queue);
kfree_skb(skb);
x25->va = (x25->va + 1) % modulus;
}
}
void x25_requeue_frames(struct sock *sk)
{
struct sk_buff *skb, *skb_prev = NULL;
/*
* Requeue all the un-ack-ed frames on the output queue to be picked
* up by x25_kick. This arrangement handles the possibility of an empty
* output queue.
*/
while ((skb = skb_dequeue(&x25_sk(sk)->ack_queue)) != NULL) {
if (!skb_prev)
skb_queue_head(&sk->sk_write_queue, skb);
else
skb_append(skb_prev, skb, &sk->sk_write_queue);
skb_prev = skb;
}
}
/*
* Validate that the value of nr is between va and vs. Return true or
* false for testing.
*/
int x25_validate_nr(struct sock *sk, unsigned short nr)
{
struct x25_sock *x25 = x25_sk(sk);
unsigned short vc = x25->va;
int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
while (vc != x25->vs) {
if (nr == vc)
return 1;
vc = (vc + 1) % modulus;
}
return nr == x25->vs ? 1 : 0;
}
/*
* This routine is called when the packet layer internally generates a
* control frame.
*/
void x25_write_internal(struct sock *sk, int frametype)
{
struct x25_sock *x25 = x25_sk(sk);
struct sk_buff *skb;
unsigned char *dptr;
unsigned char facilities[X25_MAX_FAC_LEN];
unsigned char addresses[1 + X25_ADDR_LEN];
unsigned char lci1, lci2;
/*
* Default safe frame size.
*/
int len = X25_MAX_L2_LEN + X25_EXT_MIN_LEN;
/*
* Adjust frame size.
*/
switch (frametype) {
case X25_CALL_REQUEST:
len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN +
X25_MAX_CUD_LEN;
break;
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:
len += 2;
break;
case X25_RR:
case X25_RNR:
case X25_REJ:
case X25_CLEAR_CONFIRMATION:
case X25_INTERRUPT_CONFIRMATION:
case X25_RESET_CONFIRMATION:
break;
default:
printk(KERN_ERR "X.25: invalid frame type %02X\n",
frametype);
return;
}
if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
return;
/*
* Space for Ethernet and 802.2 LLC headers.
*/
skb_reserve(skb, X25_MAX_L2_LEN);
/*
* Make space for the GFI and LCI, and fill them in.
*/
dptr = skb_put(skb, 2);
lci1 = (x25->lci >> 8) & 0x0F;
lci2 = (x25->lci >> 0) & 0xFF;
if (x25->neighbour->extended) {
*dptr++ = lci1 | X25_GFI_EXTSEQ;
*dptr++ = lci2;
} else {
*dptr++ = lci1 | X25_GFI_STDSEQ;
*dptr++ = lci2;
}
/*
* Now fill in the frame type specific information.
*/
switch (frametype) {
case X25_CALL_REQUEST:
dptr = skb_put(skb, 1);
*dptr++ = X25_CALL_REQUEST;
len = x25_addr_aton(addresses, &x25->dest_addr,
&x25->source_addr);
dptr = skb_put(skb, len);
memcpy(dptr, addresses, len);
len = x25_create_facilities(facilities,
&x25->facilities,
&x25->dte_facilities,
x25->neighbour->global_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);
x25->calluserdata.cudlength = 0;
break;
case X25_CALL_ACCEPTED:
dptr = skb_put(skb, 2);
*dptr++ = X25_CALL_ACCEPTED;
*dptr++ = 0x00; /* Address lengths */
len = x25_create_facilities(facilities,
&x25->facilities,
&x25->dte_facilities,
x25->vc_facil_mask);
dptr = skb_put(skb, len);
memcpy(dptr, facilities, len);
/* 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;
case X25_CLEAR_REQUEST:
case X25_RESET_REQUEST:
dptr = skb_put(skb, 3);
*dptr++ = frametype;
*dptr++ = 0x00; /* XXX */
*dptr++ = 0x00; /* XXX */
break;
case X25_RR:
case X25_RNR:
case X25_REJ:
if (x25->neighbour->extended) {
dptr = skb_put(skb, 2);
*dptr++ = frametype;
*dptr++ = (x25->vr << 1) & 0xFE;
} else {
dptr = skb_put(skb, 1);
*dptr = frametype;
*dptr++ |= (x25->vr << 5) & 0xE0;
}
break;
case X25_CLEAR_CONFIRMATION:
case X25_INTERRUPT_CONFIRMATION:
case X25_RESET_CONFIRMATION:
dptr = skb_put(skb, 1);
*dptr = frametype;
break;
}
x25_transmit_link(skb, x25->neighbour);
}
/*
* Unpick the contents of the passed X.25 Packet Layer frame.
*/
int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q,
int *d, int *m)
{
struct x25_sock *x25 = x25_sk(sk);
unsigned char *frame = skb->data;
*ns = *nr = *q = *d = *m = 0;
switch (frame[2]) {
case X25_CALL_REQUEST:
case X25_CALL_ACCEPTED:
case X25_CLEAR_REQUEST:
case X25_CLEAR_CONFIRMATION:
case X25_INTERRUPT:
case X25_INTERRUPT_CONFIRMATION:
case X25_RESET_REQUEST:
case X25_RESET_CONFIRMATION:
case X25_RESTART_REQUEST:
case X25_RESTART_CONFIRMATION:
case X25_REGISTRATION_REQUEST:
case X25_REGISTRATION_CONFIRMATION:
case X25_DIAGNOSTIC:
return frame[2];
}
if (x25->neighbour->extended) {
if (frame[2] == X25_RR ||
frame[2] == X25_RNR ||
frame[2] == X25_REJ) {
*nr = (frame[3] >> 1) & 0x7F;
return frame[2];
}
} else {
if ((frame[2] & 0x1F) == X25_RR ||
(frame[2] & 0x1F) == X25_RNR ||
(frame[2] & 0x1F) == X25_REJ) {
*nr = (frame[2] >> 5) & 0x07;
return frame[2] & 0x1F;
}
}
if (x25->neighbour->extended) {
if ((frame[2] & 0x01) == X25_DATA) {
*q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
*d = (frame[0] & X25_D_BIT) == X25_D_BIT;
*m = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT;
*nr = (frame[3] >> 1) & 0x7F;
*ns = (frame[2] >> 1) & 0x7F;
return X25_DATA;
}
} else {
if ((frame[2] & 0x01) == X25_DATA) {
*q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
*d = (frame[0] & X25_D_BIT) == X25_D_BIT;
*m = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT;
*nr = (frame[2] >> 5) & 0x07;
*ns = (frame[2] >> 1) & 0x07;
return X25_DATA;
}
}
printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n",
frame[0], frame[1], frame[2]);
return X25_ILLEGAL;
}
void x25_disconnect(struct sock *sk, int reason, unsigned char cause,
unsigned char diagnostic)
{
struct x25_sock *x25 = x25_sk(sk);
x25_clear_queues(sk);
x25_stop_timer(sk);
x25->lci = 0;
x25->state = X25_STATE_0;
x25->causediag.cause = cause;
x25->causediag.diagnostic = diagnostic;
sk->sk_state = TCP_CLOSE;
sk->sk_err = reason;
sk->sk_shutdown |= SEND_SHUTDOWN;
if (!sock_flag(sk, SOCK_DEAD)) {
sk->sk_state_change(sk);
sock_set_flag(sk, SOCK_DEAD);
}
}
/*
* Clear an own-rx-busy condition and tell the peer about this, provided
* that there is a significant amount of free receive buffer space available.
*/
void x25_check_rbuf(struct sock *sk)
{
struct x25_sock *x25 = x25_sk(sk);
if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) &&
(x25->condition & X25_COND_OWN_RX_BUSY)) {
x25->condition &= ~X25_COND_OWN_RX_BUSY;
x25->condition &= ~X25_COND_ACK_PENDING;
x25->vl = x25->vr;
x25_write_internal(sk, X25_RR);
x25_stop_timer(sk);
}
}
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