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293 lines
7.3 KiB
293 lines
7.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* |
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* Copyright (C) Jonathan Naylor G4KLX ([email protected]) |
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* |
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* Most of this code is based on the SDL diagrams published in the 7th ARRL |
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* Computer Networking Conference papers. The diagrams have mistakes in them, |
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* but are mostly correct. Before you modify the code could you read the SDL |
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* diagrams as the code is not obvious and probably very easy to break. |
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*/ |
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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 <net/ax25.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 <net/sock.h> |
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#include <net/tcp_states.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/rose.h> |
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/* |
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* State machine for state 1, Awaiting Call Accepted State. |
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* The handling of the timer(s) is in file rose_timer.c. |
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* Handling of state 0 and connection release is in af_rose.c. |
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*/ |
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static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype) |
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{ |
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struct rose_sock *rose = rose_sk(sk); |
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switch (frametype) { |
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case ROSE_CALL_ACCEPTED: |
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rose_stop_timer(sk); |
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rose_start_idletimer(sk); |
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rose->condition = 0x00; |
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rose->vs = 0; |
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rose->va = 0; |
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rose->vr = 0; |
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rose->vl = 0; |
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rose->state = ROSE_STATE_3; |
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sk->sk_state = TCP_ESTABLISHED; |
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if (!sock_flag(sk, SOCK_DEAD)) |
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sk->sk_state_change(sk); |
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break; |
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case ROSE_CLEAR_REQUEST: |
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rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); |
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rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]); |
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rose->neighbour->use--; |
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break; |
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default: |
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break; |
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} |
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return 0; |
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} |
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/* |
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* State machine for state 2, Awaiting Clear Confirmation State. |
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* The handling of the timer(s) is in file rose_timer.c |
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* Handling of state 0 and connection release is in af_rose.c. |
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*/ |
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static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype) |
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{ |
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struct rose_sock *rose = rose_sk(sk); |
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switch (frametype) { |
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case ROSE_CLEAR_REQUEST: |
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rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); |
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rose_disconnect(sk, 0, skb->data[3], skb->data[4]); |
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rose->neighbour->use--; |
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break; |
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case ROSE_CLEAR_CONFIRMATION: |
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rose_disconnect(sk, 0, -1, -1); |
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rose->neighbour->use--; |
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break; |
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default: |
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break; |
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} |
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return 0; |
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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 rose_timer.c |
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* Handling of state 0 and connection release is in af_rose.c. |
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*/ |
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static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m) |
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{ |
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struct rose_sock *rose = rose_sk(sk); |
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int queued = 0; |
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switch (frametype) { |
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case ROSE_RESET_REQUEST: |
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rose_stop_timer(sk); |
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rose_start_idletimer(sk); |
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rose_write_internal(sk, ROSE_RESET_CONFIRMATION); |
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rose->condition = 0x00; |
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rose->vs = 0; |
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rose->vr = 0; |
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rose->va = 0; |
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rose->vl = 0; |
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rose_requeue_frames(sk); |
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break; |
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case ROSE_CLEAR_REQUEST: |
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rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); |
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rose_disconnect(sk, 0, skb->data[3], skb->data[4]); |
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rose->neighbour->use--; |
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break; |
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case ROSE_RR: |
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case ROSE_RNR: |
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if (!rose_validate_nr(sk, nr)) { |
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rose_write_internal(sk, ROSE_RESET_REQUEST); |
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rose->condition = 0x00; |
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rose->vs = 0; |
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rose->vr = 0; |
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rose->va = 0; |
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rose->vl = 0; |
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rose->state = ROSE_STATE_4; |
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rose_start_t2timer(sk); |
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rose_stop_idletimer(sk); |
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} else { |
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rose_frames_acked(sk, nr); |
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if (frametype == ROSE_RNR) { |
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rose->condition |= ROSE_COND_PEER_RX_BUSY; |
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} else { |
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rose->condition &= ~ROSE_COND_PEER_RX_BUSY; |
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} |
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} |
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break; |
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case ROSE_DATA: /* XXX */ |
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rose->condition &= ~ROSE_COND_PEER_RX_BUSY; |
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if (!rose_validate_nr(sk, nr)) { |
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rose_write_internal(sk, ROSE_RESET_REQUEST); |
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rose->condition = 0x00; |
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rose->vs = 0; |
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rose->vr = 0; |
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rose->va = 0; |
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rose->vl = 0; |
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rose->state = ROSE_STATE_4; |
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rose_start_t2timer(sk); |
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rose_stop_idletimer(sk); |
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break; |
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} |
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rose_frames_acked(sk, nr); |
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if (ns == rose->vr) { |
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rose_start_idletimer(sk); |
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if (sk_filter_trim_cap(sk, skb, ROSE_MIN_LEN) == 0 && |
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__sock_queue_rcv_skb(sk, skb) == 0) { |
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rose->vr = (rose->vr + 1) % ROSE_MODULUS; |
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queued = 1; |
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} else { |
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/* Should never happen ! */ |
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rose_write_internal(sk, ROSE_RESET_REQUEST); |
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rose->condition = 0x00; |
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rose->vs = 0; |
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rose->vr = 0; |
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rose->va = 0; |
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rose->vl = 0; |
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rose->state = ROSE_STATE_4; |
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rose_start_t2timer(sk); |
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rose_stop_idletimer(sk); |
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break; |
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} |
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if (atomic_read(&sk->sk_rmem_alloc) > |
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(sk->sk_rcvbuf >> 1)) |
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rose->condition |= ROSE_COND_OWN_RX_BUSY; |
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} |
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/* |
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* If the window is full, ack the frame, else start the |
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* acknowledge hold back timer. |
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*/ |
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if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) { |
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rose->condition &= ~ROSE_COND_ACK_PENDING; |
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rose_stop_timer(sk); |
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rose_enquiry_response(sk); |
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} else { |
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rose->condition |= ROSE_COND_ACK_PENDING; |
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rose_start_hbtimer(sk); |
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} |
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break; |
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default: |
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printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype); |
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break; |
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} |
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return queued; |
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} |
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/* |
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* State machine for state 4, Awaiting Reset Confirmation State. |
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* The handling of the timer(s) is in file rose_timer.c |
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* Handling of state 0 and connection release is in af_rose.c. |
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*/ |
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static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype) |
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{ |
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struct rose_sock *rose = rose_sk(sk); |
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switch (frametype) { |
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case ROSE_RESET_REQUEST: |
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rose_write_internal(sk, ROSE_RESET_CONFIRMATION); |
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fallthrough; |
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case ROSE_RESET_CONFIRMATION: |
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rose_stop_timer(sk); |
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rose_start_idletimer(sk); |
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rose->condition = 0x00; |
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rose->va = 0; |
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rose->vr = 0; |
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rose->vs = 0; |
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rose->vl = 0; |
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rose->state = ROSE_STATE_3; |
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rose_requeue_frames(sk); |
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break; |
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case ROSE_CLEAR_REQUEST: |
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rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); |
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rose_disconnect(sk, 0, skb->data[3], skb->data[4]); |
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rose->neighbour->use--; |
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break; |
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default: |
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break; |
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} |
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return 0; |
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} |
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/* |
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* State machine for state 5, Awaiting Call Acceptance State. |
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* The handling of the timer(s) is in file rose_timer.c |
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* Handling of state 0 and connection release is in af_rose.c. |
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*/ |
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static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype) |
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{ |
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if (frametype == ROSE_CLEAR_REQUEST) { |
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rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); |
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rose_disconnect(sk, 0, skb->data[3], skb->data[4]); |
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rose_sk(sk)->neighbour->use--; |
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} |
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return 0; |
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} |
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/* Higher level upcall for a LAPB frame */ |
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int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb) |
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{ |
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struct rose_sock *rose = rose_sk(sk); |
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int queued = 0, frametype, ns, nr, q, d, m; |
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if (rose->state == ROSE_STATE_0) |
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return 0; |
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frametype = rose_decode(skb, &ns, &nr, &q, &d, &m); |
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switch (rose->state) { |
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case ROSE_STATE_1: |
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queued = rose_state1_machine(sk, skb, frametype); |
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break; |
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case ROSE_STATE_2: |
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queued = rose_state2_machine(sk, skb, frametype); |
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break; |
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case ROSE_STATE_3: |
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queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m); |
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break; |
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case ROSE_STATE_4: |
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queued = rose_state4_machine(sk, skb, frametype); |
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break; |
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case ROSE_STATE_5: |
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queued = rose_state5_machine(sk, skb, frametype); |
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break; |
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} |
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rose_kick(sk); |
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return queued; |
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}
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