367 lines
8.8 KiB
C
367 lines
8.8 KiB
C
/*
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* X.25 Packet Layer release 002
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*
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* This is ALPHA test software. This code may break your machine,
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* randomly fail to work with new releases, misbehave and/or generally
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* screw up. It might even work.
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*
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* This code REQUIRES 2.1.15 or higher
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*
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* This module:
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* This module is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* History
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* X.25 001 Jonathan Naylor Started coding.
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* X.25 002 Jonathan Naylor Centralised disconnection code.
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* New timer architecture.
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* 2000-03-20 Daniela Squassoni Disabling/enabling of facilities
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* negotiation.
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* 2000-11-10 Henner Eisen Check and reset for out-of-sequence
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* i-frames.
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*/
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/string.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 <net/x25.h>
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static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
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{
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struct sk_buff *skbo, *skbn = skb;
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struct x25_sock *x25 = x25_sk(sk);
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if (more) {
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x25->fraglen += skb->len;
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skb_queue_tail(&x25->fragment_queue, skb);
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skb_set_owner_r(skb, sk);
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return 0;
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}
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if (!more && x25->fraglen > 0) { /* End of fragment */
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int len = x25->fraglen + skb->len;
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if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
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kfree_skb(skb);
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return 1;
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}
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skb_queue_tail(&x25->fragment_queue, skb);
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skb_reset_transport_header(skbn);
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skbo = skb_dequeue(&x25->fragment_queue);
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skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),
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skbo->len);
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kfree_skb(skbo);
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while ((skbo =
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skb_dequeue(&x25->fragment_queue)) != NULL) {
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skb_pull(skbo, (x25->neighbour->extended) ?
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X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
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skb_copy_from_linear_data(skbo,
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skb_put(skbn, skbo->len),
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skbo->len);
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kfree_skb(skbo);
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}
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x25->fraglen = 0;
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}
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skb_set_owner_r(skbn, sk);
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skb_queue_tail(&sk->sk_receive_queue, skbn);
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if (!sock_flag(sk, SOCK_DEAD))
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sk->sk_data_ready(sk, skbn->len);
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return 0;
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}
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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 x25_timer.c.
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* Handling of state 0 and connection release is in af_x25.c.
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*/
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static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
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{
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struct x25_address source_addr, dest_addr;
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switch (frametype) {
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case X25_CALL_ACCEPTED: {
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struct x25_sock *x25 = x25_sk(sk);
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x25_stop_timer(sk);
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x25->condition = 0x00;
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x25->vs = 0;
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x25->va = 0;
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x25->vr = 0;
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x25->vl = 0;
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x25->state = X25_STATE_3;
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sk->sk_state = TCP_ESTABLISHED;
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/*
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* Parse the data in the frame.
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*/
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skb_pull(skb, X25_STD_MIN_LEN);
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skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));
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skb_pull(skb,
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x25_parse_facilities(skb, &x25->facilities,
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&x25->dte_facilities,
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&x25->vc_facil_mask));
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/*
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* Copy any Call User Data.
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*/
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if (skb->len >= 0) {
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skb_copy_from_linear_data(skb,
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x25->calluserdata.cuddata,
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skb->len);
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x25->calluserdata.cudlength = skb->len;
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}
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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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}
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case X25_CLEAR_REQUEST:
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x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
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x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
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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 x25_timer.c
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* Handling of state 0 and connection release is in af_x25.c.
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*/
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static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
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{
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switch (frametype) {
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case X25_CLEAR_REQUEST:
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x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
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x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
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break;
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case X25_CLEAR_CONFIRMATION:
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x25_disconnect(sk, 0, 0, 0);
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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 x25_timer.c
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* Handling of state 0 and connection release is in af_x25.c.
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*/
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static int x25_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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int queued = 0;
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int modulus;
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struct x25_sock *x25 = x25_sk(sk);
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modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
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switch (frametype) {
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case X25_RESET_REQUEST:
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x25_write_internal(sk, X25_RESET_CONFIRMATION);
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x25_stop_timer(sk);
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x25->condition = 0x00;
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x25->vs = 0;
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x25->vr = 0;
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x25->va = 0;
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x25->vl = 0;
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x25_requeue_frames(sk);
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break;
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case X25_CLEAR_REQUEST:
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x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
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x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
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break;
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case X25_RR:
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case X25_RNR:
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if (!x25_validate_nr(sk, nr)) {
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x25_clear_queues(sk);
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x25_write_internal(sk, X25_RESET_REQUEST);
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x25_start_t22timer(sk);
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x25->condition = 0x00;
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x25->vs = 0;
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x25->vr = 0;
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x25->va = 0;
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x25->vl = 0;
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x25->state = X25_STATE_4;
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} else {
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x25_frames_acked(sk, nr);
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if (frametype == X25_RNR) {
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x25->condition |= X25_COND_PEER_RX_BUSY;
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} else {
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x25->condition &= ~X25_COND_PEER_RX_BUSY;
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}
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}
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break;
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case X25_DATA: /* XXX */
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x25->condition &= ~X25_COND_PEER_RX_BUSY;
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if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
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x25_clear_queues(sk);
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x25_write_internal(sk, X25_RESET_REQUEST);
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x25_start_t22timer(sk);
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x25->condition = 0x00;
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x25->vs = 0;
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x25->vr = 0;
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x25->va = 0;
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x25->vl = 0;
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x25->state = X25_STATE_4;
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break;
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}
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x25_frames_acked(sk, nr);
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if (ns == x25->vr) {
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if (x25_queue_rx_frame(sk, skb, m) == 0) {
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x25->vr = (x25->vr + 1) % modulus;
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queued = 1;
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} else {
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/* Should never happen */
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x25_clear_queues(sk);
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x25_write_internal(sk, X25_RESET_REQUEST);
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x25_start_t22timer(sk);
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x25->condition = 0x00;
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x25->vs = 0;
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x25->vr = 0;
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x25->va = 0;
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x25->vl = 0;
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x25->state = X25_STATE_4;
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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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x25->condition |= X25_COND_OWN_RX_BUSY;
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}
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/*
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* If the window is full Ack it immediately, else
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* start the holdback timer.
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*/
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if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
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x25->condition &= ~X25_COND_ACK_PENDING;
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x25_stop_timer(sk);
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x25_enquiry_response(sk);
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} else {
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x25->condition |= X25_COND_ACK_PENDING;
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x25_start_t2timer(sk);
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}
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break;
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case X25_INTERRUPT_CONFIRMATION:
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x25->intflag = 0;
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break;
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case X25_INTERRUPT:
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if (sock_flag(sk, SOCK_URGINLINE))
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queued = !sock_queue_rcv_skb(sk, skb);
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else {
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skb_set_owner_r(skb, sk);
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skb_queue_tail(&x25->interrupt_in_queue, skb);
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queued = 1;
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}
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sk_send_sigurg(sk);
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x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
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break;
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default:
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printk(KERN_WARNING "x25: 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 x25_timer.c
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* Handling of state 0 and connection release is in af_x25.c.
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*/
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static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
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{
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switch (frametype) {
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case X25_RESET_REQUEST:
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x25_write_internal(sk, X25_RESET_CONFIRMATION);
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case X25_RESET_CONFIRMATION: {
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struct x25_sock *x25 = x25_sk(sk);
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x25_stop_timer(sk);
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x25->condition = 0x00;
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x25->va = 0;
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x25->vr = 0;
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x25->vs = 0;
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x25->vl = 0;
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x25->state = X25_STATE_3;
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x25_requeue_frames(sk);
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break;
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}
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case X25_CLEAR_REQUEST:
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x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
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x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
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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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/* Higher level upcall for a LAPB frame */
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int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
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{
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struct x25_sock *x25 = x25_sk(sk);
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int queued = 0, frametype, ns, nr, q, d, m;
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if (x25->state == X25_STATE_0)
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return 0;
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frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
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switch (x25->state) {
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case X25_STATE_1:
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queued = x25_state1_machine(sk, skb, frametype);
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break;
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case X25_STATE_2:
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queued = x25_state2_machine(sk, skb, frametype);
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break;
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case X25_STATE_3:
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queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
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break;
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case X25_STATE_4:
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queued = x25_state4_machine(sk, skb, frametype);
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break;
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}
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x25_kick(sk);
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return queued;
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}
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int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
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{
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int queued = x25_process_rx_frame(sk, skb);
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if (!queued)
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kfree_skb(skb);
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return 0;
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}
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