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linux/net/x25/x25_subr.c
Thomas Gleixner ee5d8f4d89 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 41 
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 18 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170858.008906948@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:27:12 +02:00

379 lines
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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
*
* 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);
skb_put_data(skb, addresses, len);
len = x25_create_facilities(facilities,
&x25->facilities,
&x25->dte_facilities,
x25->neighbour->global_facil_mask);
skb_put_data(skb, facilities, len);
skb_put_data(skb, 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);
skb_put_data(skb, 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) {
skb_put_data(skb,
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 %3ph\n", frame);
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);
}
}
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