GNU Linux-libre 4.14.266-gnu1
[releases.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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19 #include <linux/errno.h>
20 #include <linux/types.h>
21 #include <linux/socket.h>
22 #include <linux/in.h>
23 #include <linux/kernel.h>
24 #include <linux/timer.h>
25 #include <linux/string.h>
26 #include <linux/sockios.h>
27 #include <linux/net.h>
28 #include <linux/inet.h>
29 #include <linux/skbuff.h>
30 #include <linux/slab.h>
31 #include <net/sock.h>
32 #include <linux/uaccess.h>
33 #include <linux/fcntl.h>
34 #include <linux/mm.h>
35 #include <linux/interrupt.h>
36 #include <net/lapb.h>
37
38 /*
39  *  This procedure is passed a buffer descriptor for an iframe. It builds
40  *  the rest of the control part of the frame and then writes it out.
41  */
42 static void lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit)
43 {
44         unsigned char *frame;
45
46         if (!skb)
47                 return;
48
49         if (lapb->mode & LAPB_EXTENDED) {
50                 frame = skb_push(skb, 2);
51
52                 frame[0] = LAPB_I;
53                 frame[0] |= lapb->vs << 1;
54                 frame[1] = poll_bit ? LAPB_EPF : 0;
55                 frame[1] |= lapb->vr << 1;
56         } else {
57                 frame = skb_push(skb, 1);
58
59                 *frame = LAPB_I;
60                 *frame |= poll_bit ? LAPB_SPF : 0;
61                 *frame |= lapb->vr << 5;
62                 *frame |= lapb->vs << 1;
63         }
64
65         lapb_dbg(1, "(%p) S%d TX I(%d) S%d R%d\n",
66                  lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr);
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                         skbn = skb_copy(skb, GFP_ATOMIC);
91                         if (!skbn) {
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         lapb_dbg(2, "(%p) S%d TX %3ph\n", lapb->dev, lapb->state, skb->data);
153
154         if (!lapb_data_transmit(lapb, skb))
155                 kfree_skb(skb);
156 }
157
158 void lapb_establish_data_link(struct lapb_cb *lapb)
159 {
160         lapb->condition = 0x00;
161         lapb->n2count   = 0;
162
163         if (lapb->mode & LAPB_EXTENDED) {
164                 lapb_dbg(1, "(%p) S%d TX SABME(1)\n", lapb->dev, lapb->state);
165                 lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
166         } else {
167                 lapb_dbg(1, "(%p) S%d TX SABM(1)\n", lapb->dev, lapb->state);
168                 lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
169         }
170
171         lapb_start_t1timer(lapb);
172         lapb_stop_t2timer(lapb);
173 }
174
175 void lapb_enquiry_response(struct lapb_cb *lapb)
176 {
177         lapb_dbg(1, "(%p) S%d TX RR(1) R%d\n",
178                  lapb->dev, lapb->state, lapb->vr);
179
180         lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE);
181
182         lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
183 }
184
185 void lapb_timeout_response(struct lapb_cb *lapb)
186 {
187         lapb_dbg(1, "(%p) S%d TX RR(0) R%d\n",
188                  lapb->dev, lapb->state, lapb->vr);
189         lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE);
190
191         lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
192 }
193
194 void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr)
195 {
196         if (lapb->vs == nr) {
197                 lapb_frames_acked(lapb, nr);
198                 lapb_stop_t1timer(lapb);
199                 lapb->n2count = 0;
200         } else if (lapb->va != nr) {
201                 lapb_frames_acked(lapb, nr);
202                 lapb_start_t1timer(lapb);
203         }
204 }
205
206 void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf)
207 {
208         if (type == LAPB_COMMAND && pf)
209                 lapb_enquiry_response(lapb);
210 }