X25: Remove bkl in sockopts
[linux-2.6.git] / net / x25 / x25_out.c
1 /*
2  *      X.25 Packet Layer release 002
3  *
4  *      This is ALPHA test software. This code may break your machine,
5  *      randomly fail to work with new releases, misbehave and/or generally
6  *      screw up. It might even work.
7  *
8  *      This code REQUIRES 2.1.15 or higher
9  *
10  *      This module:
11  *              This module is free software; you can redistribute it and/or
12  *              modify it under the terms of the GNU General Public License
13  *              as published by the Free Software Foundation; either version
14  *              2 of the License, or (at your option) any later version.
15  *
16  *      History
17  *      X.25 001        Jonathan Naylor Started coding.
18  *      X.25 002        Jonathan Naylor New timer architecture.
19  *      2000-09-04      Henner Eisen    Prevented x25_output() skb leakage.
20  *      2000-10-27      Henner Eisen    MSG_DONTWAIT for fragment allocation.
21  *      2000-11-10      Henner Eisen    x25_send_iframe(): re-queued frames
22  *                                      needed cleaned seq-number fields.
23  */
24
25 #include <linux/slab.h>
26 #include <linux/socket.h>
27 #include <linux/kernel.h>
28 #include <linux/string.h>
29 #include <linux/skbuff.h>
30 #include <net/sock.h>
31 #include <net/x25.h>
32
33 static int x25_pacsize_to_bytes(unsigned int pacsize)
34 {
35         int bytes = 1;
36
37         if (!pacsize)
38                 return 128;
39
40         while (pacsize-- > 0)
41                 bytes *= 2;
42
43         return bytes;
44 }
45
46 /*
47  *      This is where all X.25 information frames pass.
48  *
49  *      Returns the amount of user data bytes sent on success
50  *      or a negative error code on failure.
51  */
52 int x25_output(struct sock *sk, struct sk_buff *skb)
53 {
54         struct sk_buff *skbn;
55         unsigned char header[X25_EXT_MIN_LEN];
56         int err, frontlen, len;
57         int sent=0, noblock = X25_SKB_CB(skb)->flags & MSG_DONTWAIT;
58         struct x25_sock *x25 = x25_sk(sk);
59         int header_len = x25->neighbour->extended ? X25_EXT_MIN_LEN :
60                                                     X25_STD_MIN_LEN;
61         int max_len = x25_pacsize_to_bytes(x25->facilities.pacsize_out);
62
63         if (skb->len - header_len > max_len) {
64                 /* Save a copy of the Header */
65                 skb_copy_from_linear_data(skb, header, header_len);
66                 skb_pull(skb, header_len);
67
68                 frontlen = skb_headroom(skb);
69
70                 while (skb->len > 0) {
71                         if ((skbn = sock_alloc_send_skb(sk, frontlen + max_len,
72                                                         noblock, &err)) == NULL){
73                                 if (err == -EWOULDBLOCK && noblock){
74                                         kfree_skb(skb);
75                                         return sent;
76                                 }
77                                 SOCK_DEBUG(sk, "x25_output: fragment alloc"
78                                                " failed, err=%d, %d bytes "
79                                                "sent\n", err, sent);
80                                 return err;
81                         }
82
83                         skb_reserve(skbn, frontlen);
84
85                         len = max_len > skb->len ? skb->len : max_len;
86
87                         /* Copy the user data */
88                         skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
89                         skb_pull(skb, len);
90
91                         /* Duplicate the Header */
92                         skb_push(skbn, header_len);
93                         skb_copy_to_linear_data(skbn, header, header_len);
94
95                         if (skb->len > 0) {
96                                 if (x25->neighbour->extended)
97                                         skbn->data[3] |= X25_EXT_M_BIT;
98                                 else
99                                         skbn->data[2] |= X25_STD_M_BIT;
100                         }
101
102                         skb_queue_tail(&sk->sk_write_queue, skbn);
103                         sent += len;
104                 }
105
106                 kfree_skb(skb);
107         } else {
108                 skb_queue_tail(&sk->sk_write_queue, skb);
109                 sent = skb->len - header_len;
110         }
111         return sent;
112 }
113
114 /*
115  *      This procedure is passed a buffer descriptor for an iframe. It builds
116  *      the rest of the control part of the frame and then writes it out.
117  */
118 static void x25_send_iframe(struct sock *sk, struct sk_buff *skb)
119 {
120         struct x25_sock *x25 = x25_sk(sk);
121
122         if (!skb)
123                 return;
124
125         if (x25->neighbour->extended) {
126                 skb->data[2]  = (x25->vs << 1) & 0xFE;
127                 skb->data[3] &= X25_EXT_M_BIT;
128                 skb->data[3] |= (x25->vr << 1) & 0xFE;
129         } else {
130                 skb->data[2] &= X25_STD_M_BIT;
131                 skb->data[2] |= (x25->vs << 1) & 0x0E;
132                 skb->data[2] |= (x25->vr << 5) & 0xE0;
133         }
134
135         x25_transmit_link(skb, x25->neighbour);
136 }
137
138 void x25_kick(struct sock *sk)
139 {
140         struct sk_buff *skb, *skbn;
141         unsigned short start, end;
142         int modulus;
143         struct x25_sock *x25 = x25_sk(sk);
144
145         if (x25->state != X25_STATE_3)
146                 return;
147
148         /*
149          *      Transmit interrupt data.
150          */
151         if (skb_peek(&x25->interrupt_out_queue) != NULL &&
152                 !test_and_set_bit(X25_INTERRUPT_FLAG, &x25->flags)) {
153
154                 skb = skb_dequeue(&x25->interrupt_out_queue);
155                 x25_transmit_link(skb, x25->neighbour);
156         }
157
158         if (x25->condition & X25_COND_PEER_RX_BUSY)
159                 return;
160
161         if (!skb_peek(&sk->sk_write_queue))
162                 return;
163
164         modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
165
166         start   = skb_peek(&x25->ack_queue) ? x25->vs : x25->va;
167         end     = (x25->va + x25->facilities.winsize_out) % modulus;
168
169         if (start == end)
170                 return;
171
172         x25->vs = start;
173
174         /*
175          * Transmit data until either we're out of data to send or
176          * the window is full.
177          */
178
179         skb = skb_dequeue(&sk->sk_write_queue);
180
181         do {
182                 if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
183                         skb_queue_head(&sk->sk_write_queue, skb);
184                         break;
185                 }
186
187                 skb_set_owner_w(skbn, sk);
188
189                 /*
190                  * Transmit the frame copy.
191                  */
192                 x25_send_iframe(sk, skbn);
193
194                 x25->vs = (x25->vs + 1) % modulus;
195
196                 /*
197                  * Requeue the original data frame.
198                  */
199                 skb_queue_tail(&x25->ack_queue, skb);
200
201         } while (x25->vs != end &&
202                  (skb = skb_dequeue(&sk->sk_write_queue)) != NULL);
203
204         x25->vl         = x25->vr;
205         x25->condition &= ~X25_COND_ACK_PENDING;
206
207         x25_stop_timer(sk);
208 }
209
210 /*
211  * The following routines are taken from page 170 of the 7th ARRL Computer
212  * Networking Conference paper, as is the whole state machine.
213  */
214
215 void x25_enquiry_response(struct sock *sk)
216 {
217         struct x25_sock *x25 = x25_sk(sk);
218
219         if (x25->condition & X25_COND_OWN_RX_BUSY)
220                 x25_write_internal(sk, X25_RNR);
221         else
222                 x25_write_internal(sk, X25_RR);
223
224         x25->vl         = x25->vr;
225         x25->condition &= ~X25_COND_ACK_PENDING;
226
227         x25_stop_timer(sk);
228 }