/* * This program 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. * * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) * * Most of this code is based on the SDL diagrams published in the 7th ARRL * Computer Networking Conference papers. The diagrams have mistakes in them, * but are mostly correct. Before you modify the code could you read the SDL * diagrams as the code is not obvious and probably very easy to break. */ #include <linux/errno.h> #include <linux/types.h> #include <linux/socket.h> #include <linux/in.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/timer.h> #include <linux/string.h> #include <linux/sockios.h> #include <linux/net.h> #include <net/ax25.h> #include <linux/inet.h> #include <linux/netdevice.h> #include <linux/skbuff.h> #include <net/sock.h> #include <net/tcp_states.h> #include <asm/system.h> #include <linux/fcntl.h> #include <linux/mm.h> #include <linux/interrupt.h> #include <net/rose.h> /* * State machine for state 1, Awaiting Call Accepted State. * The handling of the timer(s) is in file rose_timer.c. * Handling of state 0 and connection release is in af_rose.c. */ static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype) { struct rose_sock *rose = rose_sk(sk); switch (frametype) { case ROSE_CALL_ACCEPTED: rose_stop_timer(sk); rose_start_idletimer(sk); rose->condition = 0x00; rose->vs = 0; rose->va = 0; rose->vr = 0; rose->vl = 0; rose->state = ROSE_STATE_3; sk->sk_state = TCP_ESTABLISHED; if (!sock_flag(sk, SOCK_DEAD)) sk->sk_state_change(sk); break; case ROSE_CLEAR_REQUEST: rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]); rose->neighbour->use--; break; default: break; } return 0; } /* * State machine for state 2, Awaiting Clear Confirmation State. * The handling of the timer(s) is in file rose_timer.c * Handling of state 0 and connection release is in af_rose.c. */ static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype) { struct rose_sock *rose = rose_sk(sk); switch (frametype) { case ROSE_CLEAR_REQUEST: rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, 0, skb->data[3], skb->data[4]); rose->neighbour->use--; break; case ROSE_CLEAR_CONFIRMATION: rose_disconnect(sk, 0, -1, -1); rose->neighbour->use--; break; default: break; } return 0; } /* * State machine for state 3, Connected State. * The handling of the timer(s) is in file rose_timer.c * Handling of state 0 and connection release is in af_rose.c. */ static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m) { struct rose_sock *rose = rose_sk(sk); int queued = 0; switch (frametype) { case ROSE_RESET_REQUEST: rose_stop_timer(sk); rose_start_idletimer(sk); rose_write_internal(sk, ROSE_RESET_CONFIRMATION); rose->condition = 0x00; rose->vs = 0; rose->vr = 0; rose->va = 0; rose->vl = 0; rose_requeue_frames(sk); break; case ROSE_CLEAR_REQUEST: rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, 0, skb->data[3], skb->data[4]); rose->neighbour->use--; break; case ROSE_RR: case ROSE_RNR: if (!rose_validate_nr(sk, nr)) { rose_write_internal(sk, ROSE_RESET_REQUEST); rose->condition = 0x00; rose->vs = 0; rose->vr = 0; rose->va = 0; rose->vl = 0; rose->state = ROSE_STATE_4; rose_start_t2timer(sk); rose_stop_idletimer(sk); } else { rose_frames_acked(sk, nr); if (frametype == ROSE_RNR) { rose->condition |= ROSE_COND_PEER_RX_BUSY; } else { rose->condition &= ~ROSE_COND_PEER_RX_BUSY; } } break; case ROSE_DATA: /* XXX */ rose->condition &= ~ROSE_COND_PEER_RX_BUSY; if (!rose_validate_nr(sk, nr)) { rose_write_internal(sk, ROSE_RESET_REQUEST); rose->condition = 0x00; rose->vs = 0; rose->vr = 0; rose->va = 0; rose->vl = 0; rose->state = ROSE_STATE_4; rose_start_t2timer(sk); rose_stop_idletimer(sk); break; } rose_frames_acked(sk, nr); if (ns == rose->vr) { rose_start_idletimer(sk); if (sock_queue_rcv_skb(sk, skb) == 0) { rose->vr = (rose->vr + 1) % ROSE_MODULUS; queued = 1; } else { /* Should never happen ! */ rose_write_internal(sk, ROSE_RESET_REQUEST); rose->condition = 0x00; rose->vs = 0; rose->vr = 0; rose->va = 0; rose->vl = 0; rose->state = ROSE_STATE_4; rose_start_t2timer(sk); rose_stop_idletimer(sk); break; } if (atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf / 2)) rose->condition |= ROSE_COND_OWN_RX_BUSY; } /* * If the window is full, ack the frame, else start the * acknowledge hold back timer. */ if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) { rose->condition &= ~ROSE_COND_ACK_PENDING; rose_stop_timer(sk); rose_enquiry_response(sk); } else { rose->condition |= ROSE_COND_ACK_PENDING; rose_start_hbtimer(sk); } break; default: printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype); break; } return queued; } /* * State machine for state 4, Awaiting Reset Confirmation State. * The handling of the timer(s) is in file rose_timer.c * Handling of state 0 and connection release is in af_rose.c. */ static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype) { struct rose_sock *rose = rose_sk(sk); switch (frametype) { case ROSE_RESET_REQUEST: rose_write_internal(sk, ROSE_RESET_CONFIRMATION); case ROSE_RESET_CONFIRMATION: rose_stop_timer(sk); rose_start_idletimer(sk); rose->condition = 0x00; rose->va = 0; rose->vr = 0; rose->vs = 0; rose->vl = 0; rose->state = ROSE_STATE_3; rose_requeue_frames(sk); break; case ROSE_CLEAR_REQUEST: rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, 0, skb->data[3], skb->data[4]); rose->neighbour->use--; break; default: break; } return 0; } /* * State machine for state 5, Awaiting Call Acceptance State. * The handling of the timer(s) is in file rose_timer.c * Handling of state 0 and connection release is in af_rose.c. */ static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype) { if (frametype == ROSE_CLEAR_REQUEST) { rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, 0, skb->data[3], skb->data[4]); rose_sk(sk)->neighbour->use--; } return 0; } /* Higher level upcall for a LAPB frame */ int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb) { struct rose_sock *rose = rose_sk(sk); int queued = 0, frametype, ns, nr, q, d, m; if (rose->state == ROSE_STATE_0) return 0; frametype = rose_decode(skb, &ns, &nr, &q, &d, &m); switch (rose->state) { case ROSE_STATE_1: queued = rose_state1_machine(sk, skb, frametype); break; case ROSE_STATE_2: queued = rose_state2_machine(sk, skb, frametype); break; case ROSE_STATE_3: queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m); break; case ROSE_STATE_4: queued = rose_state4_machine(sk, skb, frametype); break; case ROSE_STATE_5: queued = rose_state5_machine(sk, skb, frametype); break; } rose_kick(sk); return queued; }