Commit | Line | Data |
---|---|---|
ee5d8f4d | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * LAPB release 002 | |
4 | * | |
5 | * This code REQUIRES 2.1.15 or higher/ NET3.038 | |
6 | * | |
1da177e4 LT |
7 | * History |
8 | * LAPB 001 Jonathan Naylor Started Coding | |
9 | * LAPB 002 Jonathan Naylor New timer architecture. | |
10 | */ | |
11 | ||
a508da6c JP |
12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
13 | ||
1da177e4 LT |
14 | #include <linux/errno.h> |
15 | #include <linux/types.h> | |
16 | #include <linux/socket.h> | |
17 | #include <linux/in.h> | |
18 | #include <linux/kernel.h> | |
1da177e4 LT |
19 | #include <linux/timer.h> |
20 | #include <linux/string.h> | |
21 | #include <linux/sockios.h> | |
22 | #include <linux/net.h> | |
23 | #include <linux/inet.h> | |
24 | #include <linux/skbuff.h> | |
5a0e3ad6 | 25 | #include <linux/slab.h> |
1da177e4 | 26 | #include <net/sock.h> |
7c0f6ba6 | 27 | #include <linux/uaccess.h> |
1da177e4 LT |
28 | #include <linux/fcntl.h> |
29 | #include <linux/mm.h> | |
30 | #include <linux/interrupt.h> | |
31 | #include <net/lapb.h> | |
32 | ||
56d6c3d7 | 33 | /* |
1da177e4 LT |
34 | * This procedure is passed a buffer descriptor for an iframe. It builds |
35 | * the rest of the control part of the frame and then writes it out. | |
36 | */ | |
37 | static void lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit) | |
38 | { | |
39 | unsigned char *frame; | |
40 | ||
41 | if (!skb) | |
42 | return; | |
43 | ||
44 | if (lapb->mode & LAPB_EXTENDED) { | |
45 | frame = skb_push(skb, 2); | |
46 | ||
47 | frame[0] = LAPB_I; | |
48 | frame[0] |= lapb->vs << 1; | |
49 | frame[1] = poll_bit ? LAPB_EPF : 0; | |
50 | frame[1] |= lapb->vr << 1; | |
51 | } else { | |
52 | frame = skb_push(skb, 1); | |
53 | ||
54 | *frame = LAPB_I; | |
55 | *frame |= poll_bit ? LAPB_SPF : 0; | |
56 | *frame |= lapb->vr << 5; | |
57 | *frame |= lapb->vs << 1; | |
58 | } | |
59 | ||
a508da6c JP |
60 | lapb_dbg(1, "(%p) S%d TX I(%d) S%d R%d\n", |
61 | lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr); | |
1da177e4 | 62 | |
56d6c3d7 | 63 | lapb_transmit_buffer(lapb, skb, LAPB_COMMAND); |
1da177e4 LT |
64 | } |
65 | ||
66 | void lapb_kick(struct lapb_cb *lapb) | |
67 | { | |
68 | struct sk_buff *skb, *skbn; | |
69 | unsigned short modulus, start, end; | |
70 | ||
71 | modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; | |
72 | start = !skb_peek(&lapb->ack_queue) ? lapb->va : lapb->vs; | |
73 | end = (lapb->va + lapb->window) % modulus; | |
74 | ||
75 | if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) && | |
76 | start != end && skb_peek(&lapb->write_queue)) { | |
77 | lapb->vs = start; | |
78 | ||
79 | /* | |
80 | * Dequeue the frame and copy it. | |
81 | */ | |
82 | skb = skb_dequeue(&lapb->write_queue); | |
83 | ||
84 | do { | |
85 | if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) { | |
86 | skb_queue_head(&lapb->write_queue, skb); | |
87 | break; | |
88 | } | |
89 | ||
90 | if (skb->sk) | |
91 | skb_set_owner_w(skbn, skb->sk); | |
92 | ||
93 | /* | |
94 | * Transmit the frame copy. | |
95 | */ | |
96 | lapb_send_iframe(lapb, skbn, LAPB_POLLOFF); | |
97 | ||
98 | lapb->vs = (lapb->vs + 1) % modulus; | |
99 | ||
100 | /* | |
101 | * Requeue the original data frame. | |
102 | */ | |
103 | skb_queue_tail(&lapb->ack_queue, skb); | |
104 | ||
105 | } while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL); | |
106 | ||
107 | lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; | |
108 | ||
109 | if (!lapb_t1timer_running(lapb)) | |
110 | lapb_start_t1timer(lapb); | |
111 | } | |
112 | } | |
113 | ||
114 | void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *skb, int type) | |
115 | { | |
116 | unsigned char *ptr; | |
117 | ||
118 | ptr = skb_push(skb, 1); | |
119 | ||
120 | if (lapb->mode & LAPB_MLP) { | |
121 | if (lapb->mode & LAPB_DCE) { | |
122 | if (type == LAPB_COMMAND) | |
123 | *ptr = LAPB_ADDR_C; | |
124 | if (type == LAPB_RESPONSE) | |
125 | *ptr = LAPB_ADDR_D; | |
126 | } else { | |
127 | if (type == LAPB_COMMAND) | |
128 | *ptr = LAPB_ADDR_D; | |
129 | if (type == LAPB_RESPONSE) | |
130 | *ptr = LAPB_ADDR_C; | |
131 | } | |
132 | } else { | |
133 | if (lapb->mode & LAPB_DCE) { | |
134 | if (type == LAPB_COMMAND) | |
135 | *ptr = LAPB_ADDR_A; | |
136 | if (type == LAPB_RESPONSE) | |
137 | *ptr = LAPB_ADDR_B; | |
138 | } else { | |
139 | if (type == LAPB_COMMAND) | |
140 | *ptr = LAPB_ADDR_B; | |
141 | if (type == LAPB_RESPONSE) | |
142 | *ptr = LAPB_ADDR_A; | |
143 | } | |
144 | } | |
145 | ||
0d08df6c | 146 | lapb_dbg(2, "(%p) S%d TX %3ph\n", lapb->dev, lapb->state, skb->data); |
1da177e4 LT |
147 | |
148 | if (!lapb_data_transmit(lapb, skb)) | |
149 | kfree_skb(skb); | |
150 | } | |
151 | ||
152 | void lapb_establish_data_link(struct lapb_cb *lapb) | |
153 | { | |
154 | lapb->condition = 0x00; | |
155 | lapb->n2count = 0; | |
156 | ||
157 | if (lapb->mode & LAPB_EXTENDED) { | |
a508da6c | 158 | lapb_dbg(1, "(%p) S%d TX SABME(1)\n", lapb->dev, lapb->state); |
1da177e4 LT |
159 | lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); |
160 | } else { | |
a508da6c | 161 | lapb_dbg(1, "(%p) S%d TX SABM(1)\n", lapb->dev, lapb->state); |
1da177e4 LT |
162 | lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); |
163 | } | |
164 | ||
165 | lapb_start_t1timer(lapb); | |
166 | lapb_stop_t2timer(lapb); | |
167 | } | |
168 | ||
169 | void lapb_enquiry_response(struct lapb_cb *lapb) | |
170 | { | |
a508da6c JP |
171 | lapb_dbg(1, "(%p) S%d TX RR(1) R%d\n", |
172 | lapb->dev, lapb->state, lapb->vr); | |
1da177e4 LT |
173 | |
174 | lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE); | |
175 | ||
176 | lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; | |
177 | } | |
178 | ||
179 | void lapb_timeout_response(struct lapb_cb *lapb) | |
180 | { | |
a508da6c JP |
181 | lapb_dbg(1, "(%p) S%d TX RR(0) R%d\n", |
182 | lapb->dev, lapb->state, lapb->vr); | |
1da177e4 LT |
183 | lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE); |
184 | ||
185 | lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; | |
186 | } | |
187 | ||
188 | void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr) | |
189 | { | |
190 | if (lapb->vs == nr) { | |
191 | lapb_frames_acked(lapb, nr); | |
192 | lapb_stop_t1timer(lapb); | |
193 | lapb->n2count = 0; | |
194 | } else if (lapb->va != nr) { | |
195 | lapb_frames_acked(lapb, nr); | |
196 | lapb_start_t1timer(lapb); | |
197 | } | |
198 | } | |
199 | ||
200 | void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf) | |
201 | { | |
202 | if (type == LAPB_COMMAND && pf) | |
203 | lapb_enquiry_response(lapb); | |
204 | } |