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1da177e4 LT |
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> | |
1da177e4 LT |
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 | ||
56d6c3d7 | 36 | /* |
1da177e4 LT |
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 | ||
56d6c3d7 | 68 | lapb_transmit_buffer(lapb, skb, LAPB_COMMAND); |
1da177e4 LT |
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 | } |