557 lines
15 KiB
C
557 lines
15 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* LAPB release 002
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*
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* This code REQUIRES 2.1.15 or higher/ NET3.038
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*
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* History
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* LAPB 001 Jonathan Naulor Started Coding
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* LAPB 002 Jonathan Naylor New timer architecture.
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* 2000-10-29 Henner Eisen lapb_data_indication() return status.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/socket.h>
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#include <linux/in.h>
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#include <linux/kernel.h>
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#include <linux/timer.h>
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#include <linux/string.h>
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#include <linux/sockios.h>
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#include <linux/net.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <net/sock.h>
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#include <linux/uaccess.h>
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#include <linux/fcntl.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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#include <net/lapb.h>
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/*
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* State machine for state 0, Disconnected State.
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* The handling of the timer(s) is in file lapb_timer.c.
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*/
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static void lapb_state0_machine(struct lapb_cb *lapb, struct sk_buff *skb,
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struct lapb_frame *frame)
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{
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switch (frame->type) {
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case LAPB_SABM:
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lapb_dbg(1, "(%p) S0 RX SABM(%d)\n", lapb->dev, frame->pf);
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if (lapb->mode & LAPB_EXTENDED) {
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lapb_dbg(1, "(%p) S0 TX DM(%d)\n",
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lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_DM, frame->pf,
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LAPB_RESPONSE);
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} else {
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lapb_dbg(1, "(%p) S0 TX UA(%d)\n",
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lapb->dev, frame->pf);
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lapb_dbg(0, "(%p) S0 -> S3\n", lapb->dev);
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lapb_send_control(lapb, LAPB_UA, frame->pf,
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LAPB_RESPONSE);
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lapb_stop_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb->state = LAPB_STATE_3;
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lapb->condition = 0x00;
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lapb->n2count = 0;
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lapb->vs = 0;
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lapb->vr = 0;
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lapb->va = 0;
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lapb_connect_indication(lapb, LAPB_OK);
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}
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break;
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case LAPB_SABME:
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lapb_dbg(1, "(%p) S0 RX SABME(%d)\n", lapb->dev, frame->pf);
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if (lapb->mode & LAPB_EXTENDED) {
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lapb_dbg(1, "(%p) S0 TX UA(%d)\n",
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lapb->dev, frame->pf);
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lapb_dbg(0, "(%p) S0 -> S3\n", lapb->dev);
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lapb_send_control(lapb, LAPB_UA, frame->pf,
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LAPB_RESPONSE);
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lapb_stop_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb->state = LAPB_STATE_3;
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lapb->condition = 0x00;
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lapb->n2count = 0;
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lapb->vs = 0;
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lapb->vr = 0;
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lapb->va = 0;
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lapb_connect_indication(lapb, LAPB_OK);
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} else {
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lapb_dbg(1, "(%p) S0 TX DM(%d)\n",
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lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_DM, frame->pf,
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LAPB_RESPONSE);
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}
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break;
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case LAPB_DISC:
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lapb_dbg(1, "(%p) S0 RX DISC(%d)\n", lapb->dev, frame->pf);
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lapb_dbg(1, "(%p) S0 TX UA(%d)\n", lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_UA, frame->pf, LAPB_RESPONSE);
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break;
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default:
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break;
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}
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kfree_skb(skb);
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}
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/*
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* State machine for state 1, Awaiting Connection State.
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* The handling of the timer(s) is in file lapb_timer.c.
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*/
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static void lapb_state1_machine(struct lapb_cb *lapb, struct sk_buff *skb,
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struct lapb_frame *frame)
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{
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switch (frame->type) {
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case LAPB_SABM:
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lapb_dbg(1, "(%p) S1 RX SABM(%d)\n", lapb->dev, frame->pf);
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if (lapb->mode & LAPB_EXTENDED) {
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lapb_dbg(1, "(%p) S1 TX DM(%d)\n",
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lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_DM, frame->pf,
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LAPB_RESPONSE);
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} else {
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lapb_dbg(1, "(%p) S1 TX UA(%d)\n",
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lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_UA, frame->pf,
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LAPB_RESPONSE);
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}
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break;
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case LAPB_SABME:
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lapb_dbg(1, "(%p) S1 RX SABME(%d)\n", lapb->dev, frame->pf);
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if (lapb->mode & LAPB_EXTENDED) {
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lapb_dbg(1, "(%p) S1 TX UA(%d)\n",
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lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_UA, frame->pf,
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LAPB_RESPONSE);
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} else {
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lapb_dbg(1, "(%p) S1 TX DM(%d)\n",
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lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_DM, frame->pf,
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LAPB_RESPONSE);
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}
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break;
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case LAPB_DISC:
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lapb_dbg(1, "(%p) S1 RX DISC(%d)\n", lapb->dev, frame->pf);
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lapb_dbg(1, "(%p) S1 TX DM(%d)\n", lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_DM, frame->pf, LAPB_RESPONSE);
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break;
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case LAPB_UA:
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lapb_dbg(1, "(%p) S1 RX UA(%d)\n", lapb->dev, frame->pf);
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if (frame->pf) {
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lapb_dbg(0, "(%p) S1 -> S3\n", lapb->dev);
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lapb_stop_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb->state = LAPB_STATE_3;
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lapb->condition = 0x00;
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lapb->n2count = 0;
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lapb->vs = 0;
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lapb->vr = 0;
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lapb->va = 0;
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lapb_connect_confirmation(lapb, LAPB_OK);
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}
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break;
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case LAPB_DM:
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lapb_dbg(1, "(%p) S1 RX DM(%d)\n", lapb->dev, frame->pf);
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if (frame->pf) {
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lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
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lapb_clear_queues(lapb);
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lapb->state = LAPB_STATE_0;
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lapb_start_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb_disconnect_indication(lapb, LAPB_REFUSED);
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}
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break;
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}
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kfree_skb(skb);
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}
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/*
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* State machine for state 2, Awaiting Release State.
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* The handling of the timer(s) is in file lapb_timer.c
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*/
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static void lapb_state2_machine(struct lapb_cb *lapb, struct sk_buff *skb,
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struct lapb_frame *frame)
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{
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switch (frame->type) {
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case LAPB_SABM:
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case LAPB_SABME:
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lapb_dbg(1, "(%p) S2 RX {SABM,SABME}(%d)\n",
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lapb->dev, frame->pf);
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lapb_dbg(1, "(%p) S2 TX DM(%d)\n", lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_DM, frame->pf, LAPB_RESPONSE);
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break;
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case LAPB_DISC:
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lapb_dbg(1, "(%p) S2 RX DISC(%d)\n", lapb->dev, frame->pf);
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lapb_dbg(1, "(%p) S2 TX UA(%d)\n", lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_UA, frame->pf, LAPB_RESPONSE);
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break;
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case LAPB_UA:
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lapb_dbg(1, "(%p) S2 RX UA(%d)\n", lapb->dev, frame->pf);
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if (frame->pf) {
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lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev);
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lapb->state = LAPB_STATE_0;
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lapb_start_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb_disconnect_confirmation(lapb, LAPB_OK);
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}
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break;
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case LAPB_DM:
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lapb_dbg(1, "(%p) S2 RX DM(%d)\n", lapb->dev, frame->pf);
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if (frame->pf) {
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lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev);
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lapb->state = LAPB_STATE_0;
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lapb_start_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb_disconnect_confirmation(lapb, LAPB_NOTCONNECTED);
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}
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break;
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case LAPB_I:
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case LAPB_REJ:
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case LAPB_RNR:
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case LAPB_RR:
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lapb_dbg(1, "(%p) S2 RX {I,REJ,RNR,RR}(%d)\n",
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lapb->dev, frame->pf);
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lapb_dbg(1, "(%p) S2 RX DM(%d)\n", lapb->dev, frame->pf);
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if (frame->pf)
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lapb_send_control(lapb, LAPB_DM, frame->pf,
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LAPB_RESPONSE);
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break;
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}
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kfree_skb(skb);
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}
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/*
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* State machine for state 3, Connected State.
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* The handling of the timer(s) is in file lapb_timer.c
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*/
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static void lapb_state3_machine(struct lapb_cb *lapb, struct sk_buff *skb,
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struct lapb_frame *frame)
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{
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int queued = 0;
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int modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS :
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LAPB_SMODULUS;
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switch (frame->type) {
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case LAPB_SABM:
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lapb_dbg(1, "(%p) S3 RX SABM(%d)\n", lapb->dev, frame->pf);
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if (lapb->mode & LAPB_EXTENDED) {
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lapb_dbg(1, "(%p) S3 TX DM(%d)\n",
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lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_DM, frame->pf,
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LAPB_RESPONSE);
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} else {
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lapb_dbg(1, "(%p) S3 TX UA(%d)\n",
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lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_UA, frame->pf,
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LAPB_RESPONSE);
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lapb_stop_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb->condition = 0x00;
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lapb->n2count = 0;
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lapb->vs = 0;
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lapb->vr = 0;
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lapb->va = 0;
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lapb_requeue_frames(lapb);
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}
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break;
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case LAPB_SABME:
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lapb_dbg(1, "(%p) S3 RX SABME(%d)\n", lapb->dev, frame->pf);
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if (lapb->mode & LAPB_EXTENDED) {
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lapb_dbg(1, "(%p) S3 TX UA(%d)\n",
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lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_UA, frame->pf,
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LAPB_RESPONSE);
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lapb_stop_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb->condition = 0x00;
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lapb->n2count = 0;
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lapb->vs = 0;
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lapb->vr = 0;
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lapb->va = 0;
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lapb_requeue_frames(lapb);
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} else {
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lapb_dbg(1, "(%p) S3 TX DM(%d)\n",
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lapb->dev, frame->pf);
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lapb_send_control(lapb, LAPB_DM, frame->pf,
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LAPB_RESPONSE);
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}
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break;
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case LAPB_DISC:
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lapb_dbg(1, "(%p) S3 RX DISC(%d)\n", lapb->dev, frame->pf);
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lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev);
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lapb_clear_queues(lapb);
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lapb_send_control(lapb, LAPB_UA, frame->pf, LAPB_RESPONSE);
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lapb_start_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb->state = LAPB_STATE_0;
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lapb_disconnect_indication(lapb, LAPB_OK);
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break;
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case LAPB_DM:
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lapb_dbg(1, "(%p) S3 RX DM(%d)\n", lapb->dev, frame->pf);
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lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev);
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lapb_clear_queues(lapb);
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lapb->state = LAPB_STATE_0;
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lapb_start_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb_disconnect_indication(lapb, LAPB_NOTCONNECTED);
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break;
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case LAPB_RNR:
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lapb_dbg(1, "(%p) S3 RX RNR(%d) R%d\n",
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lapb->dev, frame->pf, frame->nr);
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lapb->condition |= LAPB_PEER_RX_BUSY_CONDITION;
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lapb_check_need_response(lapb, frame->cr, frame->pf);
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if (lapb_validate_nr(lapb, frame->nr)) {
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lapb_check_iframes_acked(lapb, frame->nr);
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} else {
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lapb->frmr_data = *frame;
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lapb->frmr_type = LAPB_FRMR_Z;
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lapb_transmit_frmr(lapb);
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lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev);
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lapb_start_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb->state = LAPB_STATE_4;
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lapb->n2count = 0;
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}
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break;
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case LAPB_RR:
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lapb_dbg(1, "(%p) S3 RX RR(%d) R%d\n",
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lapb->dev, frame->pf, frame->nr);
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lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
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lapb_check_need_response(lapb, frame->cr, frame->pf);
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if (lapb_validate_nr(lapb, frame->nr)) {
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lapb_check_iframes_acked(lapb, frame->nr);
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} else {
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lapb->frmr_data = *frame;
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lapb->frmr_type = LAPB_FRMR_Z;
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lapb_transmit_frmr(lapb);
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lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev);
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lapb_start_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb->state = LAPB_STATE_4;
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lapb->n2count = 0;
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}
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break;
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case LAPB_REJ:
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lapb_dbg(1, "(%p) S3 RX REJ(%d) R%d\n",
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lapb->dev, frame->pf, frame->nr);
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lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
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lapb_check_need_response(lapb, frame->cr, frame->pf);
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if (lapb_validate_nr(lapb, frame->nr)) {
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lapb_frames_acked(lapb, frame->nr);
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lapb_stop_t1timer(lapb);
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lapb->n2count = 0;
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lapb_requeue_frames(lapb);
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} else {
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lapb->frmr_data = *frame;
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lapb->frmr_type = LAPB_FRMR_Z;
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lapb_transmit_frmr(lapb);
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lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev);
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lapb_start_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb->state = LAPB_STATE_4;
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lapb->n2count = 0;
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}
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break;
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case LAPB_I:
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lapb_dbg(1, "(%p) S3 RX I(%d) S%d R%d\n",
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lapb->dev, frame->pf, frame->ns, frame->nr);
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if (!lapb_validate_nr(lapb, frame->nr)) {
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lapb->frmr_data = *frame;
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lapb->frmr_type = LAPB_FRMR_Z;
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lapb_transmit_frmr(lapb);
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lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev);
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lapb_start_t1timer(lapb);
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lapb_stop_t2timer(lapb);
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lapb->state = LAPB_STATE_4;
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lapb->n2count = 0;
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break;
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}
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if (lapb->condition & LAPB_PEER_RX_BUSY_CONDITION)
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lapb_frames_acked(lapb, frame->nr);
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else
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lapb_check_iframes_acked(lapb, frame->nr);
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if (frame->ns == lapb->vr) {
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int cn;
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cn = lapb_data_indication(lapb, skb);
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queued = 1;
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/*
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* If upper layer has dropped the frame, we
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* basically ignore any further protocol
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* processing. This will cause the peer
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* to re-transmit the frame later like
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* a frame lost on the wire.
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*/
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if (cn == NET_RX_DROP) {
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pr_debug("rx congestion\n");
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break;
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}
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lapb->vr = (lapb->vr + 1) % modulus;
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lapb->condition &= ~LAPB_REJECT_CONDITION;
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if (frame->pf)
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lapb_enquiry_response(lapb);
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else {
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if (!(lapb->condition &
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LAPB_ACK_PENDING_CONDITION)) {
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lapb->condition |= LAPB_ACK_PENDING_CONDITION;
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lapb_start_t2timer(lapb);
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}
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}
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} else {
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if (lapb->condition & LAPB_REJECT_CONDITION) {
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if (frame->pf)
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lapb_enquiry_response(lapb);
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} else {
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lapb_dbg(1, "(%p) S3 TX REJ(%d) R%d\n",
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lapb->dev, frame->pf, lapb->vr);
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lapb->condition |= LAPB_REJECT_CONDITION;
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lapb_send_control(lapb, LAPB_REJ, frame->pf,
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LAPB_RESPONSE);
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lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
|
|
}
|
|
}
|
|
break;
|
|
|
|
case LAPB_FRMR:
|
|
lapb_dbg(1, "(%p) S3 RX FRMR(%d) %5ph\n",
|
|
lapb->dev, frame->pf,
|
|
skb->data);
|
|
lapb_establish_data_link(lapb);
|
|
lapb_dbg(0, "(%p) S3 -> S1\n", lapb->dev);
|
|
lapb_requeue_frames(lapb);
|
|
lapb->state = LAPB_STATE_1;
|
|
break;
|
|
|
|
case LAPB_ILLEGAL:
|
|
lapb_dbg(1, "(%p) S3 RX ILLEGAL(%d)\n", lapb->dev, frame->pf);
|
|
lapb->frmr_data = *frame;
|
|
lapb->frmr_type = LAPB_FRMR_W;
|
|
lapb_transmit_frmr(lapb);
|
|
lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev);
|
|
lapb_start_t1timer(lapb);
|
|
lapb_stop_t2timer(lapb);
|
|
lapb->state = LAPB_STATE_4;
|
|
lapb->n2count = 0;
|
|
break;
|
|
}
|
|
|
|
if (!queued)
|
|
kfree_skb(skb);
|
|
}
|
|
|
|
/*
|
|
* State machine for state 4, Frame Reject State.
|
|
* The handling of the timer(s) is in file lapb_timer.c.
|
|
*/
|
|
static void lapb_state4_machine(struct lapb_cb *lapb, struct sk_buff *skb,
|
|
struct lapb_frame *frame)
|
|
{
|
|
switch (frame->type) {
|
|
case LAPB_SABM:
|
|
lapb_dbg(1, "(%p) S4 RX SABM(%d)\n", lapb->dev, frame->pf);
|
|
if (lapb->mode & LAPB_EXTENDED) {
|
|
lapb_dbg(1, "(%p) S4 TX DM(%d)\n",
|
|
lapb->dev, frame->pf);
|
|
lapb_send_control(lapb, LAPB_DM, frame->pf,
|
|
LAPB_RESPONSE);
|
|
} else {
|
|
lapb_dbg(1, "(%p) S4 TX UA(%d)\n",
|
|
lapb->dev, frame->pf);
|
|
lapb_dbg(0, "(%p) S4 -> S3\n", lapb->dev);
|
|
lapb_send_control(lapb, LAPB_UA, frame->pf,
|
|
LAPB_RESPONSE);
|
|
lapb_stop_t1timer(lapb);
|
|
lapb_stop_t2timer(lapb);
|
|
lapb->state = LAPB_STATE_3;
|
|
lapb->condition = 0x00;
|
|
lapb->n2count = 0;
|
|
lapb->vs = 0;
|
|
lapb->vr = 0;
|
|
lapb->va = 0;
|
|
lapb_connect_indication(lapb, LAPB_OK);
|
|
}
|
|
break;
|
|
|
|
case LAPB_SABME:
|
|
lapb_dbg(1, "(%p) S4 RX SABME(%d)\n", lapb->dev, frame->pf);
|
|
if (lapb->mode & LAPB_EXTENDED) {
|
|
lapb_dbg(1, "(%p) S4 TX UA(%d)\n",
|
|
lapb->dev, frame->pf);
|
|
lapb_dbg(0, "(%p) S4 -> S3\n", lapb->dev);
|
|
lapb_send_control(lapb, LAPB_UA, frame->pf,
|
|
LAPB_RESPONSE);
|
|
lapb_stop_t1timer(lapb);
|
|
lapb_stop_t2timer(lapb);
|
|
lapb->state = LAPB_STATE_3;
|
|
lapb->condition = 0x00;
|
|
lapb->n2count = 0;
|
|
lapb->vs = 0;
|
|
lapb->vr = 0;
|
|
lapb->va = 0;
|
|
lapb_connect_indication(lapb, LAPB_OK);
|
|
} else {
|
|
lapb_dbg(1, "(%p) S4 TX DM(%d)\n",
|
|
lapb->dev, frame->pf);
|
|
lapb_send_control(lapb, LAPB_DM, frame->pf,
|
|
LAPB_RESPONSE);
|
|
}
|
|
break;
|
|
}
|
|
|
|
kfree_skb(skb);
|
|
}
|
|
|
|
/*
|
|
* Process an incoming LAPB frame
|
|
*/
|
|
void lapb_data_input(struct lapb_cb *lapb, struct sk_buff *skb)
|
|
{
|
|
struct lapb_frame frame;
|
|
|
|
if (lapb_decode(lapb, skb, &frame) < 0) {
|
|
kfree_skb(skb);
|
|
return;
|
|
}
|
|
|
|
switch (lapb->state) {
|
|
case LAPB_STATE_0:
|
|
lapb_state0_machine(lapb, skb, &frame); break;
|
|
case LAPB_STATE_1:
|
|
lapb_state1_machine(lapb, skb, &frame); break;
|
|
case LAPB_STATE_2:
|
|
lapb_state2_machine(lapb, skb, &frame); break;
|
|
case LAPB_STATE_3:
|
|
lapb_state3_machine(lapb, skb, &frame); break;
|
|
case LAPB_STATE_4:
|
|
lapb_state4_machine(lapb, skb, &frame); break;
|
|
}
|
|
|
|
lapb_kick(lapb);
|
|
}
|