339cc5f2684f1008d930c0c2ecf943d537d9294f
[linux-2.6.git] / net / lapb / lapb_out.c
1 /*
2  *      LAPB release 002
3  *
4  *      This code REQUIRES 2.1.15 or higher/ NET3.038
5  *
6  *      This module:
7  *              This module is free software; you can redistribute it and/or
8  *              modify it under the terms of the GNU General Public License
9  *              as published by the Free Software Foundation; either version
10  *              2 of the License, or (at your option) any later version.
11  *
12  *      History
13  *      LAPB 001        Jonathan Naylor Started Coding
14  *      LAPB 002        Jonathan Naylor New timer architecture.
15  */
16
17 #include <linux/errno.h>
18 #include <linux/types.h>
19 #include <linux/socket.h>
20 #include <linux/in.h>
21 #include <linux/kernel.h>
22 #include <linux/timer.h>
23 #include <linux/string.h>
24 #include <linux/sockios.h>
25 #include <linux/net.h>
26 #include <linux/inet.h>
27 #include <linux/skbuff.h>
28 #include <net/sock.h>
29 #include <asm/uaccess.h>
30 #include <asm/system.h>
31 #include <linux/fcntl.h>
32 #include <linux/mm.h>
33 #include <linux/interrupt.h>
34 #include <net/lapb.h>
35
36 /*
37  *  This procedure is passed a buffer descriptor for an iframe. It builds
38  *  the rest of the control part of the frame and then writes it out.
39  */
40 static void lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit)
41 {
42         unsigned char *frame;
43
44         if (!skb)
45                 return;
46
47         if (lapb->mode & LAPB_EXTENDED) {
48                 frame = skb_push(skb, 2);
49
50                 frame[0] = LAPB_I;
51                 frame[0] |= lapb->vs << 1;
52                 frame[1] = poll_bit ? LAPB_EPF : 0;
53                 frame[1] |= lapb->vr << 1;
54         } else {
55                 frame = skb_push(skb, 1);
56
57                 *frame = LAPB_I;
58                 *frame |= poll_bit ? LAPB_SPF : 0;
59                 *frame |= lapb->vr << 5;
60                 *frame |= lapb->vs << 1;
61         }
62
63 #if LAPB_DEBUG > 1
64         printk(KERN_DEBUG "lapb: (%p) S%d TX I(%d) S%d R%d\n",
65                lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr);
66 #endif
67
68         lapb_transmit_buffer(lapb, skb, LAPB_COMMAND);
69 }
70
71 void lapb_kick(struct lapb_cb *lapb)
72 {
73         struct sk_buff *skb, *skbn;
74         unsigned short modulus, start, end;
75
76         modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
77         start = !skb_peek(&lapb->ack_queue) ? lapb->va : lapb->vs;
78         end   = (lapb->va + lapb->window) % modulus;
79
80         if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) &&
81             start != end && skb_peek(&lapb->write_queue)) {
82                 lapb->vs = start;
83
84                 /*
85                  * Dequeue the frame and copy it.
86                  */
87                 skb = skb_dequeue(&lapb->write_queue);
88
89                 do {
90                         if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
91                                 skb_queue_head(&lapb->write_queue, skb);
92                                 break;
93                         }
94
95                         if (skb->sk)
96                                 skb_set_owner_w(skbn, skb->sk);
97
98                         /*
99                          * Transmit the frame copy.
100                          */
101                         lapb_send_iframe(lapb, skbn, LAPB_POLLOFF);
102
103                         lapb->vs = (lapb->vs + 1) % modulus;
104
105                         /*
106                          * Requeue the original data frame.
107                          */
108                         skb_queue_tail(&lapb->ack_queue, skb);
109
110                 } while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL);
111
112                 lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
113
114                 if (!lapb_t1timer_running(lapb))
115                         lapb_start_t1timer(lapb);
116         }
117 }
118
119 void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *skb, int type)
120 {
121         unsigned char *ptr;
122
123         ptr = skb_push(skb, 1);
124
125         if (lapb->mode & LAPB_MLP) {
126                 if (lapb->mode & LAPB_DCE) {
127                         if (type == LAPB_COMMAND)
128                                 *ptr = LAPB_ADDR_C;
129                         if (type == LAPB_RESPONSE)
130                                 *ptr = LAPB_ADDR_D;
131                 } else {
132                         if (type == LAPB_COMMAND)
133                                 *ptr = LAPB_ADDR_D;
134                         if (type == LAPB_RESPONSE)
135                                 *ptr = LAPB_ADDR_C;
136                 }
137         } else {
138                 if (lapb->mode & LAPB_DCE) {
139                         if (type == LAPB_COMMAND)
140                                 *ptr = LAPB_ADDR_A;
141                         if (type == LAPB_RESPONSE)
142                                 *ptr = LAPB_ADDR_B;
143                 } else {
144                         if (type == LAPB_COMMAND)
145                                 *ptr = LAPB_ADDR_B;
146                         if (type == LAPB_RESPONSE)
147                                 *ptr = LAPB_ADDR_A;
148                 }
149         }
150
151 #if LAPB_DEBUG > 2
152         printk(KERN_DEBUG "lapb: (%p) S%d TX %02X %02X %02X\n",
153                lapb->dev, lapb->state,
154                skb->data[0], skb->data[1], skb->data[2]);
155 #endif
156
157         if (!lapb_data_transmit(lapb, skb))
158                 kfree_skb(skb);
159 }
160
161 void lapb_establish_data_link(struct lapb_cb *lapb)
162 {
163         lapb->condition = 0x00;
164         lapb->n2count   = 0;
165
166         if (lapb->mode & LAPB_EXTENDED) {
167 #if LAPB_DEBUG > 1
168                 printk(KERN_DEBUG "lapb: (%p) S%d TX SABME(1)\n",
169                        lapb->dev, lapb->state);
170 #endif
171                 lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
172         } else {
173 #if LAPB_DEBUG > 1
174                 printk(KERN_DEBUG "lapb: (%p) S%d TX SABM(1)\n",
175                        lapb->dev, lapb->state);
176 #endif
177                 lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
178         }
179
180         lapb_start_t1timer(lapb);
181         lapb_stop_t2timer(lapb);
182 }
183
184 void lapb_enquiry_response(struct lapb_cb *lapb)
185 {
186 #if LAPB_DEBUG > 1
187         printk(KERN_DEBUG "lapb: (%p) S%d TX RR(1) R%d\n",
188                lapb->dev, lapb->state, lapb->vr);
189 #endif
190
191         lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE);
192
193         lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
194 }
195
196 void lapb_timeout_response(struct lapb_cb *lapb)
197 {
198 #if LAPB_DEBUG > 1
199         printk(KERN_DEBUG "lapb: (%p) S%d TX RR(0) R%d\n",
200                lapb->dev, lapb->state, lapb->vr);
201 #endif
202         lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE);
203
204         lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
205 }
206
207 void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr)
208 {
209         if (lapb->vs == nr) {
210                 lapb_frames_acked(lapb, nr);
211                 lapb_stop_t1timer(lapb);
212                 lapb->n2count = 0;
213         } else if (lapb->va != nr) {
214                 lapb_frames_acked(lapb, nr);
215                 lapb_start_t1timer(lapb);
216         }
217 }
218
219 void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf)
220 {
221         if (type == LAPB_COMMAND && pf)
222                 lapb_enquiry_response(lapb);
223 }