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/errno.h>
27 #include <linux/kernel.h>
28 #include <linux/string.h>
29 #include <linux/skbuff.h>
31 #include <net/tcp_states.h>
34 static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
36 struct sk_buff *skbo, *skbn = skb;
37 struct x25_sock *x25 = x25_sk(sk);
40 x25->fraglen += skb->len;
41 skb_queue_tail(&x25->fragment_queue, skb);
42 skb_set_owner_r(skb, sk);
46 if (!more && x25->fraglen > 0) { /* End of fragment */
47 int len = x25->fraglen + skb->len;
49 if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
54 skb_queue_tail(&x25->fragment_queue, skb);
56 skb_reset_transport_header(skbn);
58 skbo = skb_dequeue(&x25->fragment_queue);
59 memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
63 skb_dequeue(&x25->fragment_queue)) != NULL) {
64 skb_pull(skbo, (x25->neighbour->extended) ?
65 X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
66 memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
73 skb_set_owner_r(skbn, sk);
74 skb_queue_tail(&sk->sk_receive_queue, skbn);
75 if (!sock_flag(sk, SOCK_DEAD))
76 sk->sk_data_ready(sk, skbn->len);
82 * State machine for state 1, Awaiting Call Accepted State.
83 * The handling of the timer(s) is in file x25_timer.c.
84 * Handling of state 0 and connection release is in af_x25.c.
86 static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
88 struct x25_address source_addr, dest_addr;
91 case X25_CALL_ACCEPTED: {
92 struct x25_sock *x25 = x25_sk(sk);
95 x25->condition = 0x00;
100 x25->state = X25_STATE_3;
101 sk->sk_state = TCP_ESTABLISHED;
103 * Parse the data in the frame.
105 skb_pull(skb, X25_STD_MIN_LEN);
106 skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));
108 x25_parse_facilities(skb, &x25->facilities,
109 &x25->dte_facilities,
110 &x25->vc_facil_mask));
112 * Copy any Call User Data.
115 skb_copy_from_linear_data(skb,
116 x25->calluserdata.cuddata,
118 x25->calluserdata.cudlength = skb->len;
120 if (!sock_flag(sk, SOCK_DEAD))
121 sk->sk_state_change(sk);
124 case X25_CLEAR_REQUEST:
125 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
126 x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
137 * State machine for state 2, Awaiting Clear Confirmation State.
138 * The handling of the timer(s) is in file x25_timer.c
139 * Handling of state 0 and connection release is in af_x25.c.
141 static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
145 case X25_CLEAR_REQUEST:
146 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
147 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
150 case X25_CLEAR_CONFIRMATION:
151 x25_disconnect(sk, 0, 0, 0);
162 * State machine for state 3, Connected State.
163 * The handling of the timer(s) is in file x25_timer.c
164 * Handling of state 0 and connection release is in af_x25.c.
166 static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
170 struct x25_sock *x25 = x25_sk(sk);
172 modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
176 case X25_RESET_REQUEST:
177 x25_write_internal(sk, X25_RESET_CONFIRMATION);
179 x25->condition = 0x00;
184 x25_requeue_frames(sk);
187 case X25_CLEAR_REQUEST:
188 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
189 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
194 if (!x25_validate_nr(sk, nr)) {
195 x25_clear_queues(sk);
196 x25_write_internal(sk, X25_RESET_REQUEST);
197 x25_start_t22timer(sk);
198 x25->condition = 0x00;
203 x25->state = X25_STATE_4;
205 x25_frames_acked(sk, nr);
206 if (frametype == X25_RNR) {
207 x25->condition |= X25_COND_PEER_RX_BUSY;
209 x25->condition &= ~X25_COND_PEER_RX_BUSY;
214 case X25_DATA: /* XXX */
215 x25->condition &= ~X25_COND_PEER_RX_BUSY;
216 if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
217 x25_clear_queues(sk);
218 x25_write_internal(sk, X25_RESET_REQUEST);
219 x25_start_t22timer(sk);
220 x25->condition = 0x00;
225 x25->state = X25_STATE_4;
228 x25_frames_acked(sk, nr);
230 if (x25_queue_rx_frame(sk, skb, m) == 0) {
231 x25->vr = (x25->vr + 1) % modulus;
234 /* Should never happen */
235 x25_clear_queues(sk);
236 x25_write_internal(sk, X25_RESET_REQUEST);
237 x25_start_t22timer(sk);
238 x25->condition = 0x00;
243 x25->state = X25_STATE_4;
246 if (atomic_read(&sk->sk_rmem_alloc) >
248 x25->condition |= X25_COND_OWN_RX_BUSY;
251 * If the window is full Ack it immediately, else
252 * start the holdback timer.
254 if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
255 x25->condition &= ~X25_COND_ACK_PENDING;
257 x25_enquiry_response(sk);
259 x25->condition |= X25_COND_ACK_PENDING;
260 x25_start_t2timer(sk);
264 case X25_INTERRUPT_CONFIRMATION:
269 if (sock_flag(sk, SOCK_URGINLINE))
270 queued = !sock_queue_rcv_skb(sk, skb);
272 skb_set_owner_r(skb, sk);
273 skb_queue_tail(&x25->interrupt_in_queue, skb);
277 x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
281 printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
289 * State machine for state 4, Awaiting Reset Confirmation State.
290 * The handling of the timer(s) is in file x25_timer.c
291 * Handling of state 0 and connection release is in af_x25.c.
293 static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
297 case X25_RESET_REQUEST:
298 x25_write_internal(sk, X25_RESET_CONFIRMATION);
299 case X25_RESET_CONFIRMATION: {
300 struct x25_sock *x25 = x25_sk(sk);
303 x25->condition = 0x00;
308 x25->state = X25_STATE_3;
309 x25_requeue_frames(sk);
312 case X25_CLEAR_REQUEST:
313 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
314 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
324 /* Higher level upcall for a LAPB frame */
325 int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
327 struct x25_sock *x25 = x25_sk(sk);
328 int queued = 0, frametype, ns, nr, q, d, m;
330 if (x25->state == X25_STATE_0)
333 frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
335 switch (x25->state) {
337 queued = x25_state1_machine(sk, skb, frametype);
340 queued = x25_state2_machine(sk, skb, frametype);
343 queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
346 queued = x25_state4_machine(sk, skb, frametype);
355 int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
357 int queued = x25_process_rx_frame(sk, skb);