/* * LAPB release 002 * * This code REQUIRES 2.1.15 or higher/ NET3.038 * * 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 * LAPB 001 Jonathan Naylor Started Coding * LAPB 002 Jonathan Naylor New timer architecture. */ #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 <asm/uaccess.h> #include <linux/fcntl.h> #include <linux/mm.h> #include <linux/interrupt.h> #include <net/lapb.h> /* * This procedure is passed a buffer descriptor for an iframe. It builds * the rest of the control part of the frame and then writes it out. */ static void lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit) { unsigned char *frame; if (!skb) return; if (lapb->mode & LAPB_EXTENDED) { frame = skb_push(skb, 2); frame[0] = LAPB_I; frame[0] |= lapb->vs << 1; frame[1] = poll_bit ? LAPB_EPF : 0; frame[1] |= lapb->vr << 1; } else { frame = skb_push(skb, 1); *frame = LAPB_I; *frame |= poll_bit ? LAPB_SPF : 0; *frame |= lapb->vr << 5; *frame |= lapb->vs << 1; } #if LAPB_DEBUG > 1 printk(KERN_DEBUG "lapb: (%p) S%d TX I(%d) S%d R%d\n", lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr); #endif lapb_transmit_buffer(lapb, skb, LAPB_COMMAND); } void lapb_kick(struct lapb_cb *lapb) { struct sk_buff *skb, *skbn; unsigned short modulus, start, end; modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; start = !skb_peek(&lapb->ack_queue) ? lapb->va : lapb->vs; end = (lapb->va + lapb->window) % modulus; if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) && start != end && skb_peek(&lapb->write_queue)) { lapb->vs = start; /* * Dequeue the frame and copy it. */ skb = skb_dequeue(&lapb->write_queue); do { if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) { skb_queue_head(&lapb->write_queue, skb); break; } if (skb->sk) skb_set_owner_w(skbn, skb->sk); /* * Transmit the frame copy. */ lapb_send_iframe(lapb, skbn, LAPB_POLLOFF); lapb->vs = (lapb->vs + 1) % modulus; /* * Requeue the original data frame. */ skb_queue_tail(&lapb->ack_queue, skb); } while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL); lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; if (!lapb_t1timer_running(lapb)) lapb_start_t1timer(lapb); } } void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *skb, int type) { unsigned char *ptr; ptr = skb_push(skb, 1); if (lapb->mode & LAPB_MLP) { if (lapb->mode & LAPB_DCE) { if (type == LAPB_COMMAND) *ptr = LAPB_ADDR_C; if (type == LAPB_RESPONSE) *ptr = LAPB_ADDR_D; } else { if (type == LAPB_COMMAND) *ptr = LAPB_ADDR_D; if (type == LAPB_RESPONSE) *ptr = LAPB_ADDR_C; } } else { if (lapb->mode & LAPB_DCE) { if (type == LAPB_COMMAND) *ptr = LAPB_ADDR_A; if (type == LAPB_RESPONSE) *ptr = LAPB_ADDR_B; } else { if (type == LAPB_COMMAND) *ptr = LAPB_ADDR_B; if (type == LAPB_RESPONSE) *ptr = LAPB_ADDR_A; } } #if LAPB_DEBUG > 2 printk(KERN_DEBUG "lapb: (%p) S%d TX %02X %02X %02X\n", lapb->dev, lapb->state, skb->data[0], skb->data[1], skb->data[2]); #endif if (!lapb_data_transmit(lapb, skb)) kfree_skb(skb); } void lapb_establish_data_link(struct lapb_cb *lapb) { lapb->condition = 0x00; lapb->n2count = 0; if (lapb->mode & LAPB_EXTENDED) { #if LAPB_DEBUG > 1 printk(KERN_DEBUG "lapb: (%p) S%d TX SABME(1)\n", lapb->dev, lapb->state); #endif lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); } else { #if LAPB_DEBUG > 1 printk(KERN_DEBUG "lapb: (%p) S%d TX SABM(1)\n", lapb->dev, lapb->state); #endif lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); } lapb_start_t1timer(lapb); lapb_stop_t2timer(lapb); } void lapb_enquiry_response(struct lapb_cb *lapb) { #if LAPB_DEBUG > 1 printk(KERN_DEBUG "lapb: (%p) S%d TX RR(1) R%d\n", lapb->dev, lapb->state, lapb->vr); #endif lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE); lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; } void lapb_timeout_response(struct lapb_cb *lapb) { #if LAPB_DEBUG > 1 printk(KERN_DEBUG "lapb: (%p) S%d TX RR(0) R%d\n", lapb->dev, lapb->state, lapb->vr); #endif lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE); lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; } void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr) { if (lapb->vs == nr) { lapb_frames_acked(lapb, nr); lapb_stop_t1timer(lapb); lapb->n2count = 0; } else if (lapb->va != nr) { lapb_frames_acked(lapb, nr); lapb_start_t1timer(lapb); } } void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf) { if (type == LAPB_COMMAND && pf) lapb_enquiry_response(lapb); }