391 lines
9.5 KiB
C
391 lines
9.5 KiB
C
/*
|
|
* 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.
|
|
*/
|
|
|
|
#define pr_fmt(fmt) "X25: " fmt
|
|
|
|
#include <linux/slab.h>
|
|
#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:
|
|
pr_err("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:
|
|
dptr = skb_put(skb, 3);
|
|
*dptr++ = frametype;
|
|
*dptr++ = x25->causediag.cause;
|
|
*dptr++ = x25->causediag.diagnostic;
|
|
break;
|
|
|
|
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;
|
|
|
|
if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
|
|
return X25_ILLEGAL;
|
|
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) {
|
|
if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
|
|
return X25_ILLEGAL;
|
|
frame = skb->data;
|
|
|
|
*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) {
|
|
if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
|
|
return X25_ILLEGAL;
|
|
frame = skb->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;
|
|
}
|
|
}
|
|
|
|
pr_debug("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 >> 1) &&
|
|
(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);
|
|
}
|
|
}
|
|
|