Commit | Line | Data |
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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> | |
22 | #include <linux/sched.h> | |
23 | #include <linux/timer.h> | |
24 | #include <linux/string.h> | |
25 | #include <linux/sockios.h> | |
26 | #include <linux/net.h> | |
27 | #include <linux/inet.h> | |
28 | #include <linux/skbuff.h> | |
29 | #include <net/sock.h> | |
30 | #include <asm/uaccess.h> | |
31 | #include <asm/system.h> | |
32 | #include <linux/fcntl.h> | |
33 | #include <linux/mm.h> | |
34 | #include <linux/interrupt.h> | |
35 | #include <net/lapb.h> | |
36 | ||
37 | /* | |
38 | * This procedure is passed a buffer descriptor for an iframe. It builds | |
39 | * the rest of the control part of the frame and then writes it out. | |
40 | */ | |
41 | static void lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit) | |
42 | { | |
43 | unsigned char *frame; | |
44 | ||
45 | if (!skb) | |
46 | return; | |
47 | ||
48 | if (lapb->mode & LAPB_EXTENDED) { | |
49 | frame = skb_push(skb, 2); | |
50 | ||
51 | frame[0] = LAPB_I; | |
52 | frame[0] |= lapb->vs << 1; | |
53 | frame[1] = poll_bit ? LAPB_EPF : 0; | |
54 | frame[1] |= lapb->vr << 1; | |
55 | } else { | |
56 | frame = skb_push(skb, 1); | |
57 | ||
58 | *frame = LAPB_I; | |
59 | *frame |= poll_bit ? LAPB_SPF : 0; | |
60 | *frame |= lapb->vr << 5; | |
61 | *frame |= lapb->vs << 1; | |
62 | } | |
63 | ||
64 | #if LAPB_DEBUG > 1 | |
65 | printk(KERN_DEBUG "lapb: (%p) S%d TX I(%d) S%d R%d\n", | |
66 | lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr); | |
67 | #endif | |
68 | ||
69 | lapb_transmit_buffer(lapb, skb, LAPB_COMMAND); | |
70 | } | |
71 | ||
72 | void lapb_kick(struct lapb_cb *lapb) | |
73 | { | |
74 | struct sk_buff *skb, *skbn; | |
75 | unsigned short modulus, start, end; | |
76 | ||
77 | modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; | |
78 | start = !skb_peek(&lapb->ack_queue) ? lapb->va : lapb->vs; | |
79 | end = (lapb->va + lapb->window) % modulus; | |
80 | ||
81 | if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) && | |
82 | start != end && skb_peek(&lapb->write_queue)) { | |
83 | lapb->vs = start; | |
84 | ||
85 | /* | |
86 | * Dequeue the frame and copy it. | |
87 | */ | |
88 | skb = skb_dequeue(&lapb->write_queue); | |
89 | ||
90 | do { | |
91 | if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) { | |
92 | skb_queue_head(&lapb->write_queue, skb); | |
93 | break; | |
94 | } | |
95 | ||
96 | if (skb->sk) | |
97 | skb_set_owner_w(skbn, skb->sk); | |
98 | ||
99 | /* | |
100 | * Transmit the frame copy. | |
101 | */ | |
102 | lapb_send_iframe(lapb, skbn, LAPB_POLLOFF); | |
103 | ||
104 | lapb->vs = (lapb->vs + 1) % modulus; | |
105 | ||
106 | /* | |
107 | * Requeue the original data frame. | |
108 | */ | |
109 | skb_queue_tail(&lapb->ack_queue, skb); | |
110 | ||
111 | } while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL); | |
112 | ||
113 | lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; | |
114 | ||
115 | if (!lapb_t1timer_running(lapb)) | |
116 | lapb_start_t1timer(lapb); | |
117 | } | |
118 | } | |
119 | ||
120 | void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *skb, int type) | |
121 | { | |
122 | unsigned char *ptr; | |
123 | ||
124 | ptr = skb_push(skb, 1); | |
125 | ||
126 | if (lapb->mode & LAPB_MLP) { | |
127 | if (lapb->mode & LAPB_DCE) { | |
128 | if (type == LAPB_COMMAND) | |
129 | *ptr = LAPB_ADDR_C; | |
130 | if (type == LAPB_RESPONSE) | |
131 | *ptr = LAPB_ADDR_D; | |
132 | } else { | |
133 | if (type == LAPB_COMMAND) | |
134 | *ptr = LAPB_ADDR_D; | |
135 | if (type == LAPB_RESPONSE) | |
136 | *ptr = LAPB_ADDR_C; | |
137 | } | |
138 | } else { | |
139 | if (lapb->mode & LAPB_DCE) { | |
140 | if (type == LAPB_COMMAND) | |
141 | *ptr = LAPB_ADDR_A; | |
142 | if (type == LAPB_RESPONSE) | |
143 | *ptr = LAPB_ADDR_B; | |
144 | } else { | |
145 | if (type == LAPB_COMMAND) | |
146 | *ptr = LAPB_ADDR_B; | |
147 | if (type == LAPB_RESPONSE) | |
148 | *ptr = LAPB_ADDR_A; | |
149 | } | |
150 | } | |
151 | ||
152 | #if LAPB_DEBUG > 2 | |
153 | printk(KERN_DEBUG "lapb: (%p) S%d TX %02X %02X %02X\n", | |
154 | lapb->dev, lapb->state, | |
155 | skb->data[0], skb->data[1], skb->data[2]); | |
156 | #endif | |
157 | ||
158 | if (!lapb_data_transmit(lapb, skb)) | |
159 | kfree_skb(skb); | |
160 | } | |
161 | ||
162 | void lapb_establish_data_link(struct lapb_cb *lapb) | |
163 | { | |
164 | lapb->condition = 0x00; | |
165 | lapb->n2count = 0; | |
166 | ||
167 | if (lapb->mode & LAPB_EXTENDED) { | |
168 | #if LAPB_DEBUG > 1 | |
169 | printk(KERN_DEBUG "lapb: (%p) S%d TX SABME(1)\n", | |
170 | lapb->dev, lapb->state); | |
171 | #endif | |
172 | lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); | |
173 | } else { | |
174 | #if LAPB_DEBUG > 1 | |
175 | printk(KERN_DEBUG "lapb: (%p) S%d TX SABM(1)\n", | |
176 | lapb->dev, lapb->state); | |
177 | #endif | |
178 | lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); | |
179 | } | |
180 | ||
181 | lapb_start_t1timer(lapb); | |
182 | lapb_stop_t2timer(lapb); | |
183 | } | |
184 | ||
185 | void lapb_enquiry_response(struct lapb_cb *lapb) | |
186 | { | |
187 | #if LAPB_DEBUG > 1 | |
188 | printk(KERN_DEBUG "lapb: (%p) S%d TX RR(1) R%d\n", | |
189 | lapb->dev, lapb->state, lapb->vr); | |
190 | #endif | |
191 | ||
192 | lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE); | |
193 | ||
194 | lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; | |
195 | } | |
196 | ||
197 | void lapb_timeout_response(struct lapb_cb *lapb) | |
198 | { | |
199 | #if LAPB_DEBUG > 1 | |
200 | printk(KERN_DEBUG "lapb: (%p) S%d TX RR(0) R%d\n", | |
201 | lapb->dev, lapb->state, lapb->vr); | |
202 | #endif | |
203 | lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE); | |
204 | ||
205 | lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; | |
206 | } | |
207 | ||
208 | void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr) | |
209 | { | |
210 | if (lapb->vs == nr) { | |
211 | lapb_frames_acked(lapb, nr); | |
212 | lapb_stop_t1timer(lapb); | |
213 | lapb->n2count = 0; | |
214 | } else if (lapb->va != nr) { | |
215 | lapb_frames_acked(lapb, nr); | |
216 | lapb_start_t1timer(lapb); | |
217 | } | |
218 | } | |
219 | ||
220 | void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf) | |
221 | { | |
222 | if (type == LAPB_COMMAND && pf) | |
223 | lapb_enquiry_response(lapb); | |
224 | } |