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linux/net/lapb/lapb_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

300 lines
7.3 KiB
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* LAPB release 002
*
* This code REQUIRES 2.1.15 or higher/ NET3.038
*
* History
* LAPB 001 Jonathan Naylor Started Coding
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/inet.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <net/lapb.h>
/*
* This routine purges all the queues of frames.
*/
void lapb_clear_queues(struct lapb_cb *lapb)
{
skb_queue_purge(&lapb->write_queue);
skb_queue_purge(&lapb->ack_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 lapb_frames_acked(struct lapb_cb *lapb, unsigned short nr)
{
struct sk_buff *skb;
int modulus;
modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
/*
* Remove all the ack-ed frames from the ack queue.
*/
if (lapb->va != nr)
while (skb_peek(&lapb->ack_queue) && lapb->va != nr) {
skb = skb_dequeue(&lapb->ack_queue);
kfree_skb(skb);
lapb->va = (lapb->va + 1) % modulus;
}
}
void lapb_requeue_frames(struct lapb_cb *lapb)
{
struct sk_buff *skb, *skb_prev = NULL;
/*
* Requeue all the un-ack-ed frames on the output queue to be picked
* up by lapb_kick called from the timer. This arrangement handles the
* possibility of an empty output queue.
*/
while ((skb = skb_dequeue(&lapb->ack_queue)) != NULL) {
if (!skb_prev)
skb_queue_head(&lapb->write_queue, skb);
else
skb_append(skb_prev, skb, &lapb->write_queue);
skb_prev = skb;
}
}
/*
* Validate that the value of nr is between va and vs. Return true or
* false for testing.
*/
int lapb_validate_nr(struct lapb_cb *lapb, unsigned short nr)
{
unsigned short vc = lapb->va;
int modulus;
modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
while (vc != lapb->vs) {
if (nr == vc)
return 1;
vc = (vc + 1) % modulus;
}
return nr == lapb->vs;
}
/*
* This routine is the centralised routine for parsing the control
* information for the different frame formats.
*/
int lapb_decode(struct lapb_cb *lapb, struct sk_buff *skb,
struct lapb_frame *frame)
{
frame->type = LAPB_ILLEGAL;
lapb_dbg(2, "(%p) S%d RX %3ph\n", lapb->dev, lapb->state, skb->data);
/* We always need to look at 2 bytes, sometimes we need
* to look at 3 and those cases are handled below.
*/
if (!pskb_may_pull(skb, 2))
return -1;
if (lapb->mode & LAPB_MLP) {
if (lapb->mode & LAPB_DCE) {
if (skb->data[0] == LAPB_ADDR_D)
frame->cr = LAPB_COMMAND;
if (skb->data[0] == LAPB_ADDR_C)
frame->cr = LAPB_RESPONSE;
} else {
if (skb->data[0] == LAPB_ADDR_C)
frame->cr = LAPB_COMMAND;
if (skb->data[0] == LAPB_ADDR_D)
frame->cr = LAPB_RESPONSE;
}
} else {
if (lapb->mode & LAPB_DCE) {
if (skb->data[0] == LAPB_ADDR_B)
frame->cr = LAPB_COMMAND;
if (skb->data[0] == LAPB_ADDR_A)
frame->cr = LAPB_RESPONSE;
} else {
if (skb->data[0] == LAPB_ADDR_A)
frame->cr = LAPB_COMMAND;
if (skb->data[0] == LAPB_ADDR_B)
frame->cr = LAPB_RESPONSE;
}
}
skb_pull(skb, 1);
if (lapb->mode & LAPB_EXTENDED) {
if (!(skb->data[0] & LAPB_S)) {
if (!pskb_may_pull(skb, 2))
return -1;
/*
* I frame - carries NR/NS/PF
*/
frame->type = LAPB_I;
frame->ns = (skb->data[0] >> 1) & 0x7F;
frame->nr = (skb->data[1] >> 1) & 0x7F;
frame->pf = skb->data[1] & LAPB_EPF;
frame->control[0] = skb->data[0];
frame->control[1] = skb->data[1];
skb_pull(skb, 2);
} else if ((skb->data[0] & LAPB_U) == 1) {
if (!pskb_may_pull(skb, 2))
return -1;
/*
* S frame - take out PF/NR
*/
frame->type = skb->data[0] & 0x0F;
frame->nr = (skb->data[1] >> 1) & 0x7F;
frame->pf = skb->data[1] & LAPB_EPF;
frame->control[0] = skb->data[0];
frame->control[1] = skb->data[1];
skb_pull(skb, 2);
} else if ((skb->data[0] & LAPB_U) == 3) {
/*
* U frame - take out PF
*/
frame->type = skb->data[0] & ~LAPB_SPF;
frame->pf = skb->data[0] & LAPB_SPF;
frame->control[0] = skb->data[0];
frame->control[1] = 0x00;
skb_pull(skb, 1);
}
} else {
if (!(skb->data[0] & LAPB_S)) {
/*
* I frame - carries NR/NS/PF
*/
frame->type = LAPB_I;
frame->ns = (skb->data[0] >> 1) & 0x07;
frame->nr = (skb->data[0] >> 5) & 0x07;
frame->pf = skb->data[0] & LAPB_SPF;
} else if ((skb->data[0] & LAPB_U) == 1) {
/*
* S frame - take out PF/NR
*/
frame->type = skb->data[0] & 0x0F;
frame->nr = (skb->data[0] >> 5) & 0x07;
frame->pf = skb->data[0] & LAPB_SPF;
} else if ((skb->data[0] & LAPB_U) == 3) {
/*
* U frame - take out PF
*/
frame->type = skb->data[0] & ~LAPB_SPF;
frame->pf = skb->data[0] & LAPB_SPF;
}
frame->control[0] = skb->data[0];
skb_pull(skb, 1);
}
return 0;
}
/*
* This routine is called when the HDLC layer internally generates a
* command or response for the remote machine ( eg. RR, UA etc. ).
* Only supervisory or unnumbered frames are processed, FRMRs are handled
* by lapb_transmit_frmr below.
*/
void lapb_send_control(struct lapb_cb *lapb, int frametype,
int poll_bit, int type)
{
struct sk_buff *skb;
unsigned char *dptr;
if ((skb = alloc_skb(LAPB_HEADER_LEN + 3, GFP_ATOMIC)) == NULL)
return;
skb_reserve(skb, LAPB_HEADER_LEN + 1);
if (lapb->mode & LAPB_EXTENDED) {
if ((frametype & LAPB_U) == LAPB_U) {
dptr = skb_put(skb, 1);
*dptr = frametype;
*dptr |= poll_bit ? LAPB_SPF : 0;
} else {
dptr = skb_put(skb, 2);
dptr[0] = frametype;
dptr[1] = (lapb->vr << 1);
dptr[1] |= poll_bit ? LAPB_EPF : 0;
}
} else {
dptr = skb_put(skb, 1);
*dptr = frametype;
*dptr |= poll_bit ? LAPB_SPF : 0;
if ((frametype & LAPB_U) == LAPB_S) /* S frames carry NR */
*dptr |= (lapb->vr << 5);
}
lapb_transmit_buffer(lapb, skb, type);
}
/*
* This routine generates FRMRs based on information previously stored in
* the LAPB control block.
*/
void lapb_transmit_frmr(struct lapb_cb *lapb)
{
struct sk_buff *skb;
unsigned char *dptr;
if ((skb = alloc_skb(LAPB_HEADER_LEN + 7, GFP_ATOMIC)) == NULL)
return;
skb_reserve(skb, LAPB_HEADER_LEN + 1);
if (lapb->mode & LAPB_EXTENDED) {
dptr = skb_put(skb, 6);
*dptr++ = LAPB_FRMR;
*dptr++ = lapb->frmr_data.control[0];
*dptr++ = lapb->frmr_data.control[1];
*dptr++ = (lapb->vs << 1) & 0xFE;
*dptr = (lapb->vr << 1) & 0xFE;
if (lapb->frmr_data.cr == LAPB_RESPONSE)
*dptr |= 0x01;
dptr++;
*dptr++ = lapb->frmr_type;
lapb_dbg(1, "(%p) S%d TX FRMR %5ph\n",
lapb->dev, lapb->state,
&skb->data[1]);
} else {
dptr = skb_put(skb, 4);
*dptr++ = LAPB_FRMR;
*dptr++ = lapb->frmr_data.control[0];
*dptr = (lapb->vs << 1) & 0x0E;
*dptr |= (lapb->vr << 5) & 0xE0;
if (lapb->frmr_data.cr == LAPB_RESPONSE)
*dptr |= 0x10;
dptr++;
*dptr++ = lapb->frmr_type;
lapb_dbg(1, "(%p) S%d TX FRMR %3ph\n",
lapb->dev, lapb->state, &skb->data[1]);
}
lapb_transmit_buffer(lapb, skb, LAPB_RESPONSE);
}
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