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205 lines
4.7 KiB
205 lines
4.7 KiB
// 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 Naylor Started Coding |
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* LAPB 002 Jonathan Naylor New timer architecture. |
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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/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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* This procedure is passed a buffer descriptor for an iframe. It builds |
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* the rest of the control part of the frame and then writes it out. |
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*/ |
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static void lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit) |
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{ |
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unsigned char *frame; |
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if (!skb) |
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return; |
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if (lapb->mode & LAPB_EXTENDED) { |
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frame = skb_push(skb, 2); |
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frame[0] = LAPB_I; |
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frame[0] |= lapb->vs << 1; |
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frame[1] = poll_bit ? LAPB_EPF : 0; |
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frame[1] |= lapb->vr << 1; |
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} else { |
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frame = skb_push(skb, 1); |
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*frame = LAPB_I; |
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*frame |= poll_bit ? LAPB_SPF : 0; |
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*frame |= lapb->vr << 5; |
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*frame |= lapb->vs << 1; |
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} |
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lapb_dbg(1, "(%p) S%d TX I(%d) S%d R%d\n", |
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lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr); |
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lapb_transmit_buffer(lapb, skb, LAPB_COMMAND); |
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} |
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void lapb_kick(struct lapb_cb *lapb) |
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{ |
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struct sk_buff *skb, *skbn; |
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unsigned short modulus, start, end; |
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modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; |
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start = !skb_peek(&lapb->ack_queue) ? lapb->va : lapb->vs; |
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end = (lapb->va + lapb->window) % modulus; |
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if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) && |
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start != end && skb_peek(&lapb->write_queue)) { |
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lapb->vs = start; |
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/* |
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* Dequeue the frame and copy it. |
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*/ |
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skb = skb_dequeue(&lapb->write_queue); |
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do { |
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skbn = skb_copy(skb, GFP_ATOMIC); |
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if (!skbn) { |
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skb_queue_head(&lapb->write_queue, skb); |
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break; |
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} |
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if (skb->sk) |
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skb_set_owner_w(skbn, skb->sk); |
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/* |
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* Transmit the frame copy. |
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*/ |
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lapb_send_iframe(lapb, skbn, LAPB_POLLOFF); |
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lapb->vs = (lapb->vs + 1) % modulus; |
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/* |
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* Requeue the original data frame. |
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*/ |
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skb_queue_tail(&lapb->ack_queue, skb); |
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} while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL); |
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lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; |
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if (!lapb_t1timer_running(lapb)) |
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lapb_start_t1timer(lapb); |
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} |
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} |
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void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *skb, int type) |
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{ |
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unsigned char *ptr; |
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ptr = skb_push(skb, 1); |
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if (lapb->mode & LAPB_MLP) { |
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if (lapb->mode & LAPB_DCE) { |
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if (type == LAPB_COMMAND) |
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*ptr = LAPB_ADDR_C; |
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if (type == LAPB_RESPONSE) |
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*ptr = LAPB_ADDR_D; |
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} else { |
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if (type == LAPB_COMMAND) |
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*ptr = LAPB_ADDR_D; |
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if (type == LAPB_RESPONSE) |
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*ptr = LAPB_ADDR_C; |
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} |
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} else { |
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if (lapb->mode & LAPB_DCE) { |
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if (type == LAPB_COMMAND) |
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*ptr = LAPB_ADDR_A; |
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if (type == LAPB_RESPONSE) |
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*ptr = LAPB_ADDR_B; |
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} else { |
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if (type == LAPB_COMMAND) |
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*ptr = LAPB_ADDR_B; |
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if (type == LAPB_RESPONSE) |
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*ptr = LAPB_ADDR_A; |
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} |
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} |
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lapb_dbg(2, "(%p) S%d TX %3ph\n", lapb->dev, lapb->state, skb->data); |
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if (!lapb_data_transmit(lapb, skb)) |
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kfree_skb(skb); |
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} |
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void lapb_establish_data_link(struct lapb_cb *lapb) |
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{ |
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lapb->condition = 0x00; |
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lapb->n2count = 0; |
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if (lapb->mode & LAPB_EXTENDED) { |
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lapb_dbg(1, "(%p) S%d TX SABME(1)\n", lapb->dev, lapb->state); |
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lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); |
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} else { |
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lapb_dbg(1, "(%p) S%d TX SABM(1)\n", lapb->dev, lapb->state); |
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lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); |
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} |
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lapb_start_t1timer(lapb); |
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lapb_stop_t2timer(lapb); |
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} |
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void lapb_enquiry_response(struct lapb_cb *lapb) |
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{ |
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lapb_dbg(1, "(%p) S%d TX RR(1) R%d\n", |
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lapb->dev, lapb->state, lapb->vr); |
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lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE); |
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lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; |
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} |
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void lapb_timeout_response(struct lapb_cb *lapb) |
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{ |
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lapb_dbg(1, "(%p) S%d TX RR(0) R%d\n", |
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lapb->dev, lapb->state, lapb->vr); |
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lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE); |
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lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; |
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} |
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void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr) |
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{ |
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if (lapb->vs == nr) { |
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lapb_frames_acked(lapb, nr); |
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lapb_stop_t1timer(lapb); |
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lapb->n2count = 0; |
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} else if (lapb->va != nr) { |
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lapb_frames_acked(lapb, nr); |
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lapb_start_t1timer(lapb); |
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} |
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} |
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void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf) |
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{ |
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if (type == LAPB_COMMAND && pf) |
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lapb_enquiry_response(lapb); |
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}
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