2 * X.25 Packet Layer release 002
4 * This is ALPHA test software. This code may break your machine,
5 * randomly fail to work with new releases, misbehave and/or generally
6 * screw up. It might even work.
8 * This code REQUIRES 2.1.15 or higher
11 * This module is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
17 * X.25 001 Jonathan Naylor Started coding.
18 * X.25 002 Jonathan Naylor Centralised disconnection code.
19 * New timer architecture.
20 * 2000-03-20 Daniela Squassoni Disabling/enabling of facilities
22 * 2000-11-10 Henner Eisen Check and reset for out-of-sequence
26 #include <linux/slab.h>
27 #include <linux/errno.h>
28 #include <linux/kernel.h>
29 #include <linux/string.h>
30 #include <linux/skbuff.h>
32 #include <net/tcp_states.h>
35 static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
37 struct sk_buff *skbo, *skbn = skb;
38 struct x25_sock *x25 = x25_sk(sk);
41 x25->fraglen += skb->len;
42 skb_queue_tail(&x25->fragment_queue, skb);
43 skb_set_owner_r(skb, sk);
47 if (!more && x25->fraglen > 0) { /* End of fragment */
48 int len = x25->fraglen + skb->len;
50 if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
55 skb_queue_tail(&x25->fragment_queue, skb);
57 skb_reset_transport_header(skbn);
59 skbo = skb_dequeue(&x25->fragment_queue);
60 skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),
65 skb_dequeue(&x25->fragment_queue)) != NULL) {
66 skb_pull(skbo, (x25->neighbour->extended) ?
67 X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
68 skb_copy_from_linear_data(skbo,
69 skb_put(skbn, skbo->len),
77 skb_set_owner_r(skbn, sk);
78 skb_queue_tail(&sk->sk_receive_queue, skbn);
79 if (!sock_flag(sk, SOCK_DEAD))
80 sk->sk_data_ready(sk, skbn->len);
86 * State machine for state 1, Awaiting Call Accepted State.
87 * The handling of the timer(s) is in file x25_timer.c.
88 * Handling of state 0 and connection release is in af_x25.c.
90 static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
92 struct x25_address source_addr, dest_addr;
96 case X25_CALL_ACCEPTED: {
97 struct x25_sock *x25 = x25_sk(sk);
100 x25->condition = 0x00;
105 x25->state = X25_STATE_3;
106 sk->sk_state = TCP_ESTABLISHED;
108 * Parse the data in the frame.
110 skb_pull(skb, X25_STD_MIN_LEN);
112 len = x25_parse_address_block(skb, &source_addr,
117 len = x25_parse_facilities(skb, &x25->facilities,
118 &x25->dte_facilities,
119 &x25->vc_facil_mask);
123 * Copy any Call User Data.
126 skb_copy_from_linear_data(skb,
127 x25->calluserdata.cuddata,
129 x25->calluserdata.cudlength = skb->len;
131 if (!sock_flag(sk, SOCK_DEAD))
132 sk->sk_state_change(sk);
135 case X25_CLEAR_REQUEST:
136 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
137 x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
148 * State machine for state 2, Awaiting Clear Confirmation State.
149 * The handling of the timer(s) is in file x25_timer.c
150 * Handling of state 0 and connection release is in af_x25.c.
152 static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
156 case X25_CLEAR_REQUEST:
157 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
158 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
161 case X25_CLEAR_CONFIRMATION:
162 x25_disconnect(sk, 0, 0, 0);
173 * State machine for state 3, Connected State.
174 * The handling of the timer(s) is in file x25_timer.c
175 * Handling of state 0 and connection release is in af_x25.c.
177 static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
181 struct x25_sock *x25 = x25_sk(sk);
183 modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
187 case X25_RESET_REQUEST:
188 x25_write_internal(sk, X25_RESET_CONFIRMATION);
190 x25->condition = 0x00;
195 x25_requeue_frames(sk);
198 case X25_CLEAR_REQUEST:
199 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
200 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
205 if (!x25_validate_nr(sk, nr)) {
206 x25_clear_queues(sk);
207 x25_write_internal(sk, X25_RESET_REQUEST);
208 x25_start_t22timer(sk);
209 x25->condition = 0x00;
214 x25->state = X25_STATE_4;
216 x25_frames_acked(sk, nr);
217 if (frametype == X25_RNR) {
218 x25->condition |= X25_COND_PEER_RX_BUSY;
220 x25->condition &= ~X25_COND_PEER_RX_BUSY;
225 case X25_DATA: /* XXX */
226 x25->condition &= ~X25_COND_PEER_RX_BUSY;
227 if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
228 x25_clear_queues(sk);
229 x25_write_internal(sk, X25_RESET_REQUEST);
230 x25_start_t22timer(sk);
231 x25->condition = 0x00;
236 x25->state = X25_STATE_4;
239 x25_frames_acked(sk, nr);
241 if (x25_queue_rx_frame(sk, skb, m) == 0) {
242 x25->vr = (x25->vr + 1) % modulus;
245 /* Should never happen */
246 x25_clear_queues(sk);
247 x25_write_internal(sk, X25_RESET_REQUEST);
248 x25_start_t22timer(sk);
249 x25->condition = 0x00;
254 x25->state = X25_STATE_4;
257 if (atomic_read(&sk->sk_rmem_alloc) >
258 (sk->sk_rcvbuf >> 1))
259 x25->condition |= X25_COND_OWN_RX_BUSY;
262 * If the window is full Ack it immediately, else
263 * start the holdback timer.
265 if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
266 x25->condition &= ~X25_COND_ACK_PENDING;
268 x25_enquiry_response(sk);
270 x25->condition |= X25_COND_ACK_PENDING;
271 x25_start_t2timer(sk);
275 case X25_INTERRUPT_CONFIRMATION:
280 if (sock_flag(sk, SOCK_URGINLINE))
281 queued = !sock_queue_rcv_skb(sk, skb);
283 skb_set_owner_r(skb, sk);
284 skb_queue_tail(&x25->interrupt_in_queue, skb);
288 x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
292 printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
300 * State machine for state 4, Awaiting Reset Confirmation State.
301 * The handling of the timer(s) is in file x25_timer.c
302 * Handling of state 0 and connection release is in af_x25.c.
304 static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
308 case X25_RESET_REQUEST:
309 x25_write_internal(sk, X25_RESET_CONFIRMATION);
310 case X25_RESET_CONFIRMATION: {
311 struct x25_sock *x25 = x25_sk(sk);
314 x25->condition = 0x00;
319 x25->state = X25_STATE_3;
320 x25_requeue_frames(sk);
323 case X25_CLEAR_REQUEST:
324 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
325 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
335 /* Higher level upcall for a LAPB frame */
336 int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
338 struct x25_sock *x25 = x25_sk(sk);
339 int queued = 0, frametype, ns, nr, q, d, m;
341 if (x25->state == X25_STATE_0)
344 frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
346 switch (x25->state) {
348 queued = x25_state1_machine(sk, skb, frametype);
351 queued = x25_state2_machine(sk, skb, frametype);
354 queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
357 queued = x25_state4_machine(sk, skb, frametype);
366 int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
368 int queued = x25_process_rx_frame(sk, skb);