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/*
 *      AX.25 release 037
 *
 *      This code REQUIRES 2.1.15 or higher/ NET3.038
 *
 *      This module:
 *              This module is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 *
 *      Most of this code is based on the SDL diagrams published in the 7th
 *      ARRL Computer Networking Conference papers. The diagrams have mistakes
 *      in them, but are mostly correct. Before you modify the code could you
 *      read the SDL diagrams as the code is not obvious and probably very
 *      easy to break;
 *
 *      History
 *      AX.25 029       Alan(GW4PTS)    Switched to KA9Q constant names. Removed
 *                                      old BSD code.
 *      AX.25 030       Jonathan(G4KLX) Added support for extended AX.25.
 *                                      Added fragmentation support.
 *                      Darryl(G7LED)   Added function ax25_requeue_frames() to split
 *                                      it up from ax25_frames_acked().
 *      AX.25 031       Joerg(DL1BKE)   DAMA needs KISS Fullduplex ON/OFF.
 *                                      Thus we have ax25_kiss_cmd() now... ;-)
 *                      Dave Brown(N2RJT)
 *                                      Killed a silly bug in the DAMA code.
 *                      Joerg(DL1BKE)   Found the real bug in ax25.h, sri.
 *      AX.25 032       Joerg(DL1BKE)   Added ax25_queue_length to count the number of
 *                                      enqueued buffers of a socket..
 *      AX.25 035       Frederic(F1OAT) Support for pseudo-digipeating.
 *      AX.25 037       Jonathan(G4KLX) New timer architecture.
 */
 
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
 
/*
 *      This routine purges all the queues of frames.
 */
void ax25_clear_queues(ax25_cb *ax25)
{
        skb_queue_purge(&ax25->write_queue);
        skb_queue_purge(&ax25->ack_queue);
        skb_queue_purge(&ax25->reseq_queue);
        skb_queue_purge(&ax25->frag_queue);
}
 
/*
 * This routine purges the input queue of those frames that have been
 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
 * SDL diagram.
 */
void ax25_frames_acked(ax25_cb *ax25, unsigned short nr)
{
        struct sk_buff *skb;
 
        /*
         * Remove all the ack-ed frames from the ack queue.
         */
        if (ax25->va != nr) {
                while (skb_peek(&ax25->ack_queue) != NULL && ax25->va != nr) {
                        skb = skb_dequeue(&ax25->ack_queue);
                        kfree_skb(skb);
                        ax25->va = (ax25->va + 1) % ax25->modulus;
                }
        }
}
 
void ax25_requeue_frames(ax25_cb *ax25)
{
        struct sk_buff *skb, *skb_prev = NULL;
 
        /*
         * Requeue all the un-ack-ed frames on the output queue to be picked
         * up by ax25_kick called from the timer. This arrangement handles the
         * possibility of an empty output queue.
         */
        while ((skb = skb_dequeue(&ax25->ack_queue)) != NULL) {
                if (skb_prev == NULL)
                        skb_queue_head(&ax25->write_queue, skb);
                else
                        skb_append(skb_prev, skb);
                skb_prev = skb;
        }
}
 
/*
 *      Validate that the value of nr is between va and vs. Return true or
 *      false for testing.
 */
int ax25_validate_nr(ax25_cb *ax25, unsigned short nr)
{
        unsigned short vc = ax25->va;
 
        while (vc != ax25->vs) {
                if (nr == vc) return 1;
                vc = (vc + 1) % ax25->modulus;
        }
 
        if (nr == ax25->vs) return 1;
 
        return 0;
}
 
/*
 *      This routine is the centralised routine for parsing the control
 *      information for the different frame formats.
 */
int ax25_decode(ax25_cb *ax25, struct sk_buff *skb, int *ns, int *nr, int *pf)
{
        unsigned char *frame;
        int frametype = AX25_ILLEGAL;
 
        frame = skb->data;
        *ns = *nr = *pf = 0;
 
        if (ax25->modulus == AX25_MODULUS) {
                if ((frame[0] & AX25_S) == 0) {
                        frametype = AX25_I;                     /* I frame - carries NR/NS/PF */
                        *ns = (frame[0] >> 1) & 0x07;
                        *nr = (frame[0] >> 5) & 0x07;
                        *pf = frame[0] & AX25_PF;
                } else if ((frame[0] & AX25_U) == 1) {   /* S frame - take out PF/NR */
                        frametype = frame[0] & 0x0F;
                        *nr = (frame[0] >> 5) & 0x07;
                        *pf = frame[0] & AX25_PF;
                } else if ((frame[0] & AX25_U) == 3) {   /* U frame - take out PF */
                        frametype = frame[0] & ~AX25_PF;
                        *pf = frame[0] & AX25_PF;
                }
                skb_pull(skb, 1);
        } else {
                if ((frame[0] & AX25_S) == 0) {
                        frametype = AX25_I;                     /* I frame - carries NR/NS/PF */
                        *ns = (frame[0] >> 1) & 0x7F;
                        *nr = (frame[1] >> 1) & 0x7F;
                        *pf = frame[1] & AX25_EPF;
                        skb_pull(skb, 2);
                } else if ((frame[0] & AX25_U) == 1) {   /* S frame - take out PF/NR */
                        frametype = frame[0] & 0x0F;
                        *nr = (frame[1] >> 1) & 0x7F;
                        *pf = frame[1] & AX25_EPF;
                        skb_pull(skb, 2);
                } else if ((frame[0] & AX25_U) == 3) {   /* U frame - take out PF */
                        frametype = frame[0] & ~AX25_PF;
                        *pf = frame[0] & AX25_PF;
                        skb_pull(skb, 1);
                }
        }
 
        return frametype;
}
 
/*
 *      This routine is called when the HDLC layer internally  generates a
 *      command or  response  for  the remote machine ( eg. RR, UA etc. ).
 *      Only supervisory or unnumbered frames are processed.
 */
void ax25_send_control(ax25_cb *ax25, int frametype, int poll_bit, int type)
{
        struct sk_buff *skb;
        unsigned char  *dptr;
 
        if ((skb = alloc_skb(AX25_BPQ_HEADER_LEN + ax25_addr_size(ax25->digipeat) + 2, GFP_ATOMIC)) == NULL)
                return;
 
        skb_reserve(skb, AX25_BPQ_HEADER_LEN + ax25_addr_size(ax25->digipeat));
 
        skb->nh.raw = skb->data;
 
        /* Assume a response - address structure for DTE */
        if (ax25->modulus == AX25_MODULUS) {
                dptr = skb_put(skb, 1);
                *dptr = frametype;
                *dptr |= (poll_bit) ? AX25_PF : 0;
                if ((frametype & AX25_U) == AX25_S)             /* S frames carry NR */
                        *dptr |= (ax25->vr << 5);
        } else {
                if ((frametype & AX25_U) == AX25_U) {
                        dptr = skb_put(skb, 1);
                        *dptr = frametype;
                        *dptr |= (poll_bit) ? AX25_PF : 0;
                } else {
                        dptr = skb_put(skb, 2);
                        dptr[0] = frametype;
                        dptr[1] = (ax25->vr << 1);
                        dptr[1] |= (poll_bit) ? AX25_EPF : 0;
                }
        }
 
        ax25_transmit_buffer(ax25, skb, type);
}
 
/*
 *      Send a 'DM' to an unknown connection attempt, or an invalid caller.
 *
 *      Note: src here is the sender, thus it's the target of the DM
 */
void ax25_return_dm(struct net_device *dev, ax25_address *src, ax25_address *dest, ax25_digi *digi)
{
        struct sk_buff *skb;
        char *dptr;
        ax25_digi retdigi;
 
        if (dev == NULL)
                return;
 
        if ((skb = alloc_skb(AX25_BPQ_HEADER_LEN + ax25_addr_size(digi) + 1, GFP_ATOMIC)) == NULL)
                return; /* Next SABM will get DM'd */
 
        skb_reserve(skb, AX25_BPQ_HEADER_LEN + ax25_addr_size(digi));
        skb->nh.raw = skb->data;
 
        ax25_digi_invert(digi, &retdigi);
 
        dptr = skb_put(skb, 1);
 
        *dptr = AX25_DM | AX25_PF;
 
        /*
         *      Do the address ourselves
         */
        dptr  = skb_push(skb, ax25_addr_size(digi));
        dptr += ax25_addr_build(dptr, dest, src, &retdigi, AX25_RESPONSE, AX25_MODULUS);
 
        skb->dev      = dev;
 
        ax25_queue_xmit(skb);
}
 
/*
 *      Exponential backoff for AX.25
 */
void ax25_calculate_t1(ax25_cb *ax25)
{
        int n, t = 2;
 
        switch (ax25->backoff) {
                case 0:
                        break;
 
                case 1:
                        t += 2 * ax25->n2count;
                        break;
 
                case 2:
                        for (n = 0; n < ax25->n2count; n++)
                                t *= 2;
                        if (t > 8) t = 8;
                        break;
        }
 
        ax25->t1 = t * ax25->rtt;
}
 
/*
 *      Calculate the Round Trip Time
 */
void ax25_calculate_rtt(ax25_cb *ax25)
{
        if (ax25->backoff == 0)
                return;
 
        if (ax25_t1timer_running(ax25) && ax25->n2count == 0)
                ax25->rtt = (9 * ax25->rtt + ax25->t1 - ax25_display_timer(&ax25->t1timer)) / 10;
 
        if (ax25->rtt < AX25_T1CLAMPLO)
                ax25->rtt = AX25_T1CLAMPLO;
 
        if (ax25->rtt > AX25_T1CLAMPHI)
                ax25->rtt = AX25_T1CLAMPHI;
}
 
void ax25_disconnect(ax25_cb *ax25, int reason)
{
        ax25_clear_queues(ax25);
 
        ax25_stop_t1timer(ax25);
        ax25_stop_t2timer(ax25);
        ax25_stop_t3timer(ax25);
        ax25_stop_idletimer(ax25);
 
        ax25->state = AX25_STATE_0;
 
        ax25_link_failed(ax25, reason);
 
        if (ax25->sk != NULL) {
                ax25->sk->state     = TCP_CLOSE;
                ax25->sk->err       = reason;
                ax25->sk->shutdown |= SEND_SHUTDOWN;
                if (!ax25->sk->dead)
                        ax25->sk->state_change(ax25->sk);
                ax25->sk->dead      = 1;
        }
}

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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [net/] [ax25/] [ax25_subr.c] - Blame information for rev 1765

Line No.	Rev	Author	Line
1	1275	phoenix	`/*`
2			`* AX.25 release 037`
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			`* Most of this code is based on the SDL diagrams published in the 7th`
13			`* ARRL Computer Networking Conference papers. The diagrams have mistakes`
14			`* in them, but are mostly correct. Before you modify the code could you`
15			`* read the SDL diagrams as the code is not obvious and probably very`
16			`* easy to break;`
17			`*`
18			`* History`
19			`* AX.25 029 Alan(GW4PTS) Switched to KA9Q constant names. Removed`
20			`* old BSD code.`
21			`* AX.25 030 Jonathan(G4KLX) Added support for extended AX.25.`
22			`* Added fragmentation support.`
23			`* Darryl(G7LED) Added function ax25_requeue_frames() to split`
24			`* it up from ax25_frames_acked().`
25			`* AX.25 031 Joerg(DL1BKE) DAMA needs KISS Fullduplex ON/OFF.`
26			`* Thus we have ax25_kiss_cmd() now... ;-)`
27			`* Dave Brown(N2RJT)`
28			`* Killed a silly bug in the DAMA code.`
29			`* Joerg(DL1BKE) Found the real bug in ax25.h, sri.`
30			`* AX.25 032 Joerg(DL1BKE) Added ax25_queue_length to count the number of`
31			`* enqueued buffers of a socket..`
32			`* AX.25 035 Frederic(F1OAT) Support for pseudo-digipeating.`
33			`* AX.25 037 Jonathan(G4KLX) New timer architecture.`
34			`*/`
35
36			`#include <linux/errno.h>`
37			`#include <linux/types.h>`
38			`#include <linux/socket.h>`
39			`#include <linux/in.h>`
40			`#include <linux/kernel.h>`
41			`#include <linux/sched.h>`
42			`#include <linux/timer.h>`
43			`#include <linux/string.h>`
44			`#include <linux/sockios.h>`
45			`#include <linux/net.h>`
46			`#include <net/ax25.h>`
47			`#include <linux/inet.h>`
48			`#include <linux/netdevice.h>`
49			`#include <linux/skbuff.h>`
50			`#include <net/sock.h>`
51			`#include <asm/uaccess.h>`
52			`#include <asm/system.h>`
53			`#include <linux/fcntl.h>`
54			`#include <linux/mm.h>`
55			`#include <linux/interrupt.h>`
56
57			`/*`
58			`* This routine purges all the queues of frames.`
59			`*/`
60			`void ax25_clear_queues(ax25_cb *ax25)`
61			`{`
62			`skb_queue_purge(&ax25->write_queue);`
63			`skb_queue_purge(&ax25->ack_queue);`
64			`skb_queue_purge(&ax25->reseq_queue);`
65			`skb_queue_purge(&ax25->frag_queue);`
66			`}`
67
68			`/*`
69			`* This routine purges the input queue of those frames that have been`
70			`* acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the`
71			`* SDL diagram.`
72			`*/`
73			`void ax25_frames_acked(ax25_cb *ax25, unsigned short nr)`
74			`{`
75			`struct sk_buff *skb;`
76
77			`/*`
78			`* Remove all the ack-ed frames from the ack queue.`
79			`*/`
80			`if (ax25->va != nr) {`
81			`while (skb_peek(&ax25->ack_queue) != NULL && ax25->va != nr) {`
82			`skb = skb_dequeue(&ax25->ack_queue);`
83			`kfree_skb(skb);`
84			`ax25->va = (ax25->va + 1) % ax25->modulus;`
85			`}`
86			`}`
87			`}`
88
89			`void ax25_requeue_frames(ax25_cb *ax25)`
90			`{`
91			`struct sk_buff skb, skb_prev = NULL;`
92
93			`/*`
94			`* Requeue all the un-ack-ed frames on the output queue to be picked`
95			`* up by ax25_kick called from the timer. This arrangement handles the`
96			`* possibility of an empty output queue.`
97			`*/`
98			`while ((skb = skb_dequeue(&ax25->ack_queue)) != NULL) {`
99			`if (skb_prev == NULL)`
100			`skb_queue_head(&ax25->write_queue, skb);`
101			`else`
102			`skb_append(skb_prev, skb);`
103			`skb_prev = skb;`
104			`}`
105			`}`
106
107			`/*`
108			`* Validate that the value of nr is between va and vs. Return true or`
109			`* false for testing.`
110			`*/`
111			`int ax25_validate_nr(ax25_cb *ax25, unsigned short nr)`
112			`{`
113			`unsigned short vc = ax25->va;`
114
115			`while (vc != ax25->vs) {`
116			`if (nr == vc) return 1;`
117			`vc = (vc + 1) % ax25->modulus;`
118			`}`
119
120			`if (nr == ax25->vs) return 1;`
121
122			`return 0;`
123			`}`
124
125			`/*`
126			`* This routine is the centralised routine for parsing the control`
127			`* information for the different frame formats.`
128			`*/`
129			`int ax25_decode(ax25_cb ax25, struct sk_buff skb, int ns, int nr, int *pf)`
130			`{`
131			`unsigned char *frame;`
132			`int frametype = AX25_ILLEGAL;`
133
134			`frame = skb->data;`
135			`ns = nr = *pf = 0;`
136
137			`if (ax25->modulus == AX25_MODULUS) {`
138			`if ((frame[0] & AX25_S) == 0) {`
139			`frametype = AX25_I; /* I frame - carries NR/NS/PF */`
140			`*ns = (frame[0] >> 1) & 0x07;`
141			`*nr = (frame[0] >> 5) & 0x07;`
142			`*pf = frame[0] & AX25_PF;`
143			`} else if ((frame[0] & AX25_U) == 1) { /* S frame - take out PF/NR */`
144			`frametype = frame[0] & 0x0F;`
145			`*nr = (frame[0] >> 5) & 0x07;`
146			`*pf = frame[0] & AX25_PF;`
147			`} else if ((frame[0] & AX25_U) == 3) { /* U frame - take out PF */`
148			`frametype = frame[0] & ~AX25_PF;`
149			`*pf = frame[0] & AX25_PF;`
150			`}`
151			`skb_pull(skb, 1);`
152			`} else {`
153			`if ((frame[0] & AX25_S) == 0) {`
154			`frametype = AX25_I; /* I frame - carries NR/NS/PF */`
155			`*ns = (frame[0] >> 1) & 0x7F;`
156			`*nr = (frame[1] >> 1) & 0x7F;`
157			`*pf = frame[1] & AX25_EPF;`
158			`skb_pull(skb, 2);`
159			`} else if ((frame[0] & AX25_U) == 1) { /* S frame - take out PF/NR */`
160			`frametype = frame[0] & 0x0F;`
161			`*nr = (frame[1] >> 1) & 0x7F;`
162			`*pf = frame[1] & AX25_EPF;`
163			`skb_pull(skb, 2);`
164			`} else if ((frame[0] & AX25_U) == 3) { /* U frame - take out PF */`
165			`frametype = frame[0] & ~AX25_PF;`
166			`*pf = frame[0] & AX25_PF;`
167			`skb_pull(skb, 1);`
168			`}`
169			`}`
170
171			`return frametype;`
172			`}`
173
174			`/*`
175			`* This routine is called when the HDLC layer internally generates a`
176			`* command or response for the remote machine ( eg. RR, UA etc. ).`
177			`* Only supervisory or unnumbered frames are processed.`
178			`*/`
179			`void ax25_send_control(ax25_cb *ax25, int frametype, int poll_bit, int type)`
180			`{`
181			`struct sk_buff *skb;`
182			`unsigned char *dptr;`
183
184			`if ((skb = alloc_skb(AX25_BPQ_HEADER_LEN + ax25_addr_size(ax25->digipeat) + 2, GFP_ATOMIC)) == NULL)`
185			`return;`
186
187			`skb_reserve(skb, AX25_BPQ_HEADER_LEN + ax25_addr_size(ax25->digipeat));`
188
189			`skb->nh.raw = skb->data;`
190
191			`/* Assume a response - address structure for DTE */`
192			`if (ax25->modulus == AX25_MODULUS) {`
193			`dptr = skb_put(skb, 1);`
194			`*dptr = frametype;`
195			`*dptr \|= (poll_bit) ? AX25_PF : 0;`
196			`if ((frametype & AX25_U) == AX25_S) /* S frames carry NR */`
197			`*dptr \|= (ax25->vr << 5);`
198			`} else {`
199			`if ((frametype & AX25_U) == AX25_U) {`
200			`dptr = skb_put(skb, 1);`
201			`*dptr = frametype;`
202			`*dptr \|= (poll_bit) ? AX25_PF : 0;`
203			`} else {`
204			`dptr = skb_put(skb, 2);`
205			`dptr[0] = frametype;`
206			`dptr[1] = (ax25->vr << 1);`
207			`dptr[1] \|= (poll_bit) ? AX25_EPF : 0;`
208			`}`
209			`}`
210
211			`ax25_transmit_buffer(ax25, skb, type);`
212			`}`
213
214			`/*`
215			`* Send a 'DM' to an unknown connection attempt, or an invalid caller.`
216			`*`
217			`* Note: src here is the sender, thus it's the target of the DM`
218			`*/`
219			`void ax25_return_dm(struct net_device dev, ax25_address src, ax25_address dest, ax25_digi digi)`
220			`{`
221			`struct sk_buff *skb;`
222			`char *dptr;`
223			`ax25_digi retdigi;`
224
225			`if (dev == NULL)`
226			`return;`
227
228			`if ((skb = alloc_skb(AX25_BPQ_HEADER_LEN + ax25_addr_size(digi) + 1, GFP_ATOMIC)) == NULL)`
229			`return; /* Next SABM will get DM'd */`
230
231			`skb_reserve(skb, AX25_BPQ_HEADER_LEN + ax25_addr_size(digi));`
232			`skb->nh.raw = skb->data;`
233
234			`ax25_digi_invert(digi, &retdigi);`
235
236			`dptr = skb_put(skb, 1);`
237
238			`*dptr = AX25_DM \| AX25_PF;`
239
240			`/*`
241			`* Do the address ourselves`
242			`*/`
243			`dptr = skb_push(skb, ax25_addr_size(digi));`
244			`dptr += ax25_addr_build(dptr, dest, src, &retdigi, AX25_RESPONSE, AX25_MODULUS);`
245
246			`skb->dev = dev;`
247
248			`ax25_queue_xmit(skb);`
249			`}`
250
251			`/*`
252			`* Exponential backoff for AX.25`
253			`*/`
254			`void ax25_calculate_t1(ax25_cb *ax25)`
255			`{`
256			`int n, t = 2;`
257
258			`switch (ax25->backoff) {`
259			`case 0:`
260			`break;`
261
262			`case 1:`
263			`t += 2 * ax25->n2count;`
264			`break;`
265
266			`case 2:`
267			`for (n = 0; n < ax25->n2count; n++)`
268			`t *= 2;`
269			`if (t > 8) t = 8;`
270			`break;`
271			`}`
272
273			`ax25->t1 = t * ax25->rtt;`
274			`}`
275
276			`/*`
277			`* Calculate the Round Trip Time`
278			`*/`
279			`void ax25_calculate_rtt(ax25_cb *ax25)`
280			`{`
281			`if (ax25->backoff == 0)`
282			`return;`
283
284			`if (ax25_t1timer_running(ax25) && ax25->n2count == 0)`
285			`ax25->rtt = (9 * ax25->rtt + ax25->t1 - ax25_display_timer(&ax25->t1timer)) / 10;`
286
287			`if (ax25->rtt < AX25_T1CLAMPLO)`
288			`ax25->rtt = AX25_T1CLAMPLO;`
289
290			`if (ax25->rtt > AX25_T1CLAMPHI)`
291			`ax25->rtt = AX25_T1CLAMPHI;`
292			`}`
293
294			`void ax25_disconnect(ax25_cb *ax25, int reason)`
295			`{`
296			`ax25_clear_queues(ax25);`
297
298			`ax25_stop_t1timer(ax25);`
299			`ax25_stop_t2timer(ax25);`
300			`ax25_stop_t3timer(ax25);`
301			`ax25_stop_idletimer(ax25);`
302
303			`ax25->state = AX25_STATE_0;`
304
305			`ax25_link_failed(ax25, reason);`
306
307			`if (ax25->sk != NULL) {`
308			`ax25->sk->state = TCP_CLOSE;`
309			`ax25->sk->err = reason;`
310			`ax25->sk->shutdown \|= SEND_SHUTDOWN;`
311			`if (!ax25->sk->dead)`
312			`ax25->sk->state_change(ax25->sk);`
313			`ax25->sk->dead = 1;`
314			`}`
315			`}`