2 * Generic HDLC support routines for Linux
3 * Point-to-point protocol support
5 * Copyright (C) 1999 - 2008 Krzysztof Halasa <khc@pm.waw.pl>
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of version 2 of the GNU General Public License
9 * as published by the Free Software Foundation.
12 #include <linux/errno.h>
13 #include <linux/hdlc.h>
14 #include <linux/if_arp.h>
15 #include <linux/inetdevice.h>
16 #include <linux/init.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/pkt_sched.h>
20 #include <linux/poll.h>
21 #include <linux/skbuff.h>
22 #include <linux/slab.h>
23 #include <linux/spinlock.h>
25 #define DEBUG_CP 0 /* also bytes# to dump */
27 #define DEBUG_HARD_HEADER 0
29 #define HDLC_ADDR_ALLSTATIONS 0xFF
30 #define HDLC_CTRL_UI 0x03
32 #define PID_LCP 0xC021
34 #define PID_IPCP 0x8021
35 #define PID_IPV6 0x0057
36 #define PID_IPV6CP 0x8057
38 enum {IDX_LCP
= 0, IDX_IPCP
, IDX_IPV6CP
, IDX_COUNT
};
39 enum {CP_CONF_REQ
= 1, CP_CONF_ACK
, CP_CONF_NAK
, CP_CONF_REJ
, CP_TERM_REQ
,
40 CP_TERM_ACK
, CP_CODE_REJ
, LCP_PROTO_REJ
, LCP_ECHO_REQ
, LCP_ECHO_REPLY
,
41 LCP_DISC_REQ
, CP_CODES
};
43 static const char *const code_names
[CP_CODES
] = {
44 "0", "ConfReq", "ConfAck", "ConfNak", "ConfRej", "TermReq",
45 "TermAck", "CodeRej", "ProtoRej", "EchoReq", "EchoReply", "Discard"
47 static char debug_buffer
[64 + 3 * DEBUG_CP
];
50 enum {LCP_OPTION_MRU
= 1, LCP_OPTION_ACCM
, LCP_OPTION_MAGIC
= 5};
66 struct net_device
*dev
;
67 struct timer_list timer
;
68 unsigned long timeout
;
69 u16 pid
; /* protocol ID */
71 u8 cr_id
; /* ID of last Configuration-Request */
76 struct proto protos
[IDX_COUNT
];
78 unsigned long last_pong
;
79 unsigned int req_timeout
, cr_retries
, term_retries
;
80 unsigned int keepalive_interval
, keepalive_timeout
;
81 u8 seq
; /* local sequence number for requests */
82 u8 echo_id
; /* ID of last Echo-Request (LCP) */
85 enum {CLOSED
= 0, STOPPED
, STOPPING
, REQ_SENT
, ACK_RECV
, ACK_SENT
, OPENED
,
86 STATES
, STATE_MASK
= 0xF};
87 enum {START
= 0, STOP
, TO_GOOD
, TO_BAD
, RCR_GOOD
, RCR_BAD
, RCA
, RCN
, RTR
, RTA
,
88 RUC
, RXJ_GOOD
, RXJ_BAD
, EVENTS
};
89 enum {INV
= 0x10, IRC
= 0x20, ZRC
= 0x40, SCR
= 0x80, SCA
= 0x100,
90 SCN
= 0x200, STR
= 0x400, STA
= 0x800, SCJ
= 0x1000};
93 static const char *const state_names
[STATES
] = {
94 "Closed", "Stopped", "Stopping", "ReqSent", "AckRecv", "AckSent",
97 static const char *const event_names
[EVENTS
] = {
98 "Start", "Stop", "TO+", "TO-", "RCR+", "RCR-", "RCA", "RCN",
99 "RTR", "RTA", "RUC", "RXJ+", "RXJ-"
103 static struct sk_buff_head tx_queue
; /* used when holding the spin lock */
105 static int ppp_ioctl(struct net_device
*dev
, struct ifreq
*ifr
);
107 static inline struct ppp
* get_ppp(struct net_device
*dev
)
109 return (struct ppp
*)dev_to_hdlc(dev
)->state
;
112 static inline struct proto
* get_proto(struct net_device
*dev
, u16 pid
)
114 struct ppp
*ppp
= get_ppp(dev
);
118 return &ppp
->protos
[IDX_LCP
];
120 return &ppp
->protos
[IDX_IPCP
];
122 return &ppp
->protos
[IDX_IPV6CP
];
128 static inline const char* proto_name(u16 pid
)
142 static __be16
ppp_type_trans(struct sk_buff
*skb
, struct net_device
*dev
)
144 struct hdlc_header
*data
= (struct hdlc_header
*)skb
->data
;
146 if (skb
->len
< sizeof(struct hdlc_header
))
147 return htons(ETH_P_HDLC
);
148 if (data
->address
!= HDLC_ADDR_ALLSTATIONS
||
149 data
->control
!= HDLC_CTRL_UI
)
150 return htons(ETH_P_HDLC
);
152 switch (data
->protocol
) {
153 case cpu_to_be16(PID_IP
):
154 skb_pull(skb
, sizeof(struct hdlc_header
));
155 return htons(ETH_P_IP
);
157 case cpu_to_be16(PID_IPV6
):
158 skb_pull(skb
, sizeof(struct hdlc_header
));
159 return htons(ETH_P_IPV6
);
162 return htons(ETH_P_HDLC
);
167 static int ppp_hard_header(struct sk_buff
*skb
, struct net_device
*dev
,
168 u16 type
, const void *daddr
, const void *saddr
,
171 struct hdlc_header
*data
;
172 #if DEBUG_HARD_HEADER
173 printk(KERN_DEBUG
"%s: ppp_hard_header() called\n", dev
->name
);
176 skb_push(skb
, sizeof(struct hdlc_header
));
177 data
= (struct hdlc_header
*)skb
->data
;
179 data
->address
= HDLC_ADDR_ALLSTATIONS
;
180 data
->control
= HDLC_CTRL_UI
;
183 data
->protocol
= htons(PID_IP
);
186 data
->protocol
= htons(PID_IPV6
);
191 data
->protocol
= htons(type
);
193 default: /* unknown protocol */
196 return sizeof(struct hdlc_header
);
200 static void ppp_tx_flush(void)
203 while ((skb
= skb_dequeue(&tx_queue
)) != NULL
)
207 static void ppp_tx_cp(struct net_device
*dev
, u16 pid
, u8 code
,
208 u8 id
, unsigned int len
, const void *data
)
211 struct cp_header
*cp
;
212 unsigned int magic_len
= 0;
220 if (pid
== PID_LCP
&& (code
== LCP_ECHO_REQ
|| code
== LCP_ECHO_REPLY
))
221 magic_len
= sizeof(magic
);
223 skb
= dev_alloc_skb(sizeof(struct hdlc_header
) +
224 sizeof(struct cp_header
) + magic_len
+ len
);
226 printk(KERN_WARNING
"%s: out of memory in ppp_tx_cp()\n",
230 skb_reserve(skb
, sizeof(struct hdlc_header
));
232 cp
= (struct cp_header
*)skb_put(skb
, sizeof(struct cp_header
));
235 cp
->len
= htons(sizeof(struct cp_header
) + magic_len
+ len
);
238 memcpy(skb_put(skb
, magic_len
), &magic
, magic_len
);
240 memcpy(skb_put(skb
, len
), data
, len
);
243 BUG_ON(code
>= CP_CODES
);
246 for (i
= 0; i
< min_t(unsigned int, magic_len
+ len
, DEBUG_CP
); i
++) {
247 sprintf(ptr
, " %02X", skb
->data
[sizeof(struct cp_header
) + i
]);
250 printk(KERN_DEBUG
"%s: TX %s [%s id 0x%X]%s\n", dev
->name
,
251 proto_name(pid
), code_names
[code
], id
, debug_buffer
);
254 ppp_hard_header(skb
, dev
, pid
, NULL
, NULL
, 0);
256 skb
->priority
= TC_PRIO_CONTROL
;
258 skb_reset_network_header(skb
);
259 skb_queue_tail(&tx_queue
, skb
);
263 /* State transition table (compare STD-51)
265 TO+ = Timeout with counter > 0 irc = Initialize-Restart-Count
266 TO- = Timeout with counter expired zrc = Zero-Restart-Count
268 RCR+ = Receive-Configure-Request (Good) scr = Send-Configure-Request
269 RCR- = Receive-Configure-Request (Bad)
270 RCA = Receive-Configure-Ack sca = Send-Configure-Ack
271 RCN = Receive-Configure-Nak/Rej scn = Send-Configure-Nak/Rej
273 RTR = Receive-Terminate-Request str = Send-Terminate-Request
274 RTA = Receive-Terminate-Ack sta = Send-Terminate-Ack
276 RUC = Receive-Unknown-Code scj = Send-Code-Reject
277 RXJ+ = Receive-Code-Reject (permitted)
278 or Receive-Protocol-Reject
279 RXJ- = Receive-Code-Reject (catastrophic)
280 or Receive-Protocol-Reject
282 static int cp_table
[EVENTS
][STATES
] = {
283 /* CLOSED STOPPED STOPPING REQ_SENT ACK_RECV ACK_SENT OPENED
285 {IRC
|SCR
|3, INV
, INV
, INV
, INV
, INV
, INV
}, /* START */
286 { INV
, 0 , 0 , 0 , 0 , 0 , 0 }, /* STOP */
287 { INV
, INV
,STR
|2, SCR
|3 ,SCR
|3, SCR
|5 , INV
}, /* TO+ */
288 { INV
, INV
, 1 , 1 , 1 , 1 , INV
}, /* TO- */
289 { STA
|0 ,IRC
|SCR
|SCA
|5, 2 , SCA
|5 ,SCA
|6, SCA
|5 ,SCR
|SCA
|5}, /* RCR+ */
290 { STA
|0 ,IRC
|SCR
|SCN
|3, 2 , SCN
|3 ,SCN
|4, SCN
|3 ,SCR
|SCN
|3}, /* RCR- */
291 { STA
|0 , STA
|1 , 2 , IRC
|4 ,SCR
|3, 6 , SCR
|3 }, /* RCA */
292 { STA
|0 , STA
|1 , 2 ,IRC
|SCR
|3,SCR
|3,IRC
|SCR
|5, SCR
|3 }, /* RCN */
293 { STA
|0 , STA
|1 ,STA
|2, STA
|3 ,STA
|3, STA
|3 ,ZRC
|STA
|2}, /* RTR */
294 { 0 , 1 , 1 , 3 , 3 , 5 , SCR
|3 }, /* RTA */
295 { SCJ
|0 , SCJ
|1 ,SCJ
|2, SCJ
|3 ,SCJ
|4, SCJ
|5 , SCJ
|6 }, /* RUC */
296 { 0 , 1 , 2 , 3 , 3 , 5 , 6 }, /* RXJ+ */
297 { 0 , 1 , 1 , 1 , 1 , 1 ,IRC
|STR
|2}, /* RXJ- */
301 /* SCA: RCR+ must supply id, len and data
302 SCN: RCR- must supply code, id, len and data
303 STA: RTR must supply id
304 SCJ: RUC must supply CP packet len and data */
305 static void ppp_cp_event(struct net_device
*dev
, u16 pid
, u16 event
, u8 code
,
306 u8 id
, unsigned int len
, const void *data
)
308 int old_state
, action
;
309 struct ppp
*ppp
= get_ppp(dev
);
310 struct proto
*proto
= get_proto(dev
, pid
);
312 old_state
= proto
->state
;
313 BUG_ON(old_state
>= STATES
);
314 BUG_ON(event
>= EVENTS
);
317 printk(KERN_DEBUG
"%s: %s ppp_cp_event(%s) %s ...\n", dev
->name
,
318 proto_name(pid
), event_names
[event
], state_names
[proto
->state
]);
321 action
= cp_table
[event
][old_state
];
323 proto
->state
= action
& STATE_MASK
;
324 if (action
& (SCR
| STR
)) /* set Configure-Req/Terminate-Req timer */
325 mod_timer(&proto
->timer
, proto
->timeout
=
326 jiffies
+ ppp
->req_timeout
* HZ
);
328 proto
->restart_counter
= 0;
330 proto
->restart_counter
= (proto
->state
== STOPPING
) ?
331 ppp
->term_retries
: ppp
->cr_retries
;
333 if (action
& SCR
) /* send Configure-Request */
334 ppp_tx_cp(dev
, pid
, CP_CONF_REQ
, proto
->cr_id
= ++ppp
->seq
,
336 if (action
& SCA
) /* send Configure-Ack */
337 ppp_tx_cp(dev
, pid
, CP_CONF_ACK
, id
, len
, data
);
338 if (action
& SCN
) /* send Configure-Nak/Reject */
339 ppp_tx_cp(dev
, pid
, code
, id
, len
, data
);
340 if (action
& STR
) /* send Terminate-Request */
341 ppp_tx_cp(dev
, pid
, CP_TERM_REQ
, ++ppp
->seq
, 0, NULL
);
342 if (action
& STA
) /* send Terminate-Ack */
343 ppp_tx_cp(dev
, pid
, CP_TERM_ACK
, id
, 0, NULL
);
344 if (action
& SCJ
) /* send Code-Reject */
345 ppp_tx_cp(dev
, pid
, CP_CODE_REJ
, ++ppp
->seq
, len
, data
);
347 if (old_state
!= OPENED
&& proto
->state
== OPENED
) {
348 printk(KERN_INFO
"%s: %s up\n", dev
->name
, proto_name(pid
));
349 if (pid
== PID_LCP
) {
350 netif_dormant_off(dev
);
351 ppp_cp_event(dev
, PID_IPCP
, START
, 0, 0, 0, NULL
);
352 ppp_cp_event(dev
, PID_IPV6CP
, START
, 0, 0, 0, NULL
);
353 ppp
->last_pong
= jiffies
;
354 mod_timer(&proto
->timer
, proto
->timeout
=
355 jiffies
+ ppp
->keepalive_interval
* HZ
);
358 if (old_state
== OPENED
&& proto
->state
!= OPENED
) {
359 printk(KERN_INFO
"%s: %s down\n", dev
->name
, proto_name(pid
));
360 if (pid
== PID_LCP
) {
361 netif_dormant_on(dev
);
362 ppp_cp_event(dev
, PID_IPCP
, STOP
, 0, 0, 0, NULL
);
363 ppp_cp_event(dev
, PID_IPV6CP
, STOP
, 0, 0, 0, NULL
);
366 if (old_state
!= CLOSED
&& proto
->state
== CLOSED
)
367 del_timer(&proto
->timer
);
370 printk(KERN_DEBUG
"%s: %s ppp_cp_event(%s) ... %s\n", dev
->name
,
371 proto_name(pid
), event_names
[event
], state_names
[proto
->state
]);
376 static void ppp_cp_parse_cr(struct net_device
*dev
, u16 pid
, u8 id
,
377 unsigned int req_len
, const u8
*data
)
379 static u8
const valid_accm
[6] = { LCP_OPTION_ACCM
, 6, 0, 0, 0, 0 };
382 unsigned int len
= req_len
, nak_len
= 0, rej_len
= 0;
384 if (!(out
= kmalloc(len
, GFP_ATOMIC
))) {
385 dev
->stats
.rx_dropped
++;
386 return; /* out of memory, ignore CR packet */
389 for (opt
= data
; len
; len
-= opt
[1], opt
+= opt
[1]) {
390 if (len
< 2 || len
< opt
[1]) {
391 dev
->stats
.rx_errors
++;
393 return; /* bad packet, drop silently */
399 continue; /* MRU always OK and > 1500 bytes? */
401 case LCP_OPTION_ACCM
: /* async control character map */
402 if (!memcmp(opt
, valid_accm
,
405 if (!rej_len
) { /* NAK it */
406 memcpy(out
+ nak_len
, valid_accm
,
408 nak_len
+= sizeof(valid_accm
);
412 case LCP_OPTION_MAGIC
:
413 if (opt
[1] != 6 || (!opt
[2] && !opt
[3] &&
415 break; /* reject invalid magic number */
418 /* reject this option */
419 memcpy(out
+ rej_len
, opt
, opt
[1]);
424 ppp_cp_event(dev
, pid
, RCR_BAD
, CP_CONF_REJ
, id
, rej_len
, out
);
426 ppp_cp_event(dev
, pid
, RCR_BAD
, CP_CONF_NAK
, id
, nak_len
, out
);
428 ppp_cp_event(dev
, pid
, RCR_GOOD
, CP_CONF_ACK
, id
, req_len
, data
);
433 static int ppp_rx(struct sk_buff
*skb
)
435 struct hdlc_header
*hdr
= (struct hdlc_header
*)skb
->data
;
436 struct net_device
*dev
= skb
->dev
;
437 struct ppp
*ppp
= get_ppp(dev
);
439 struct cp_header
*cp
;
448 spin_lock_irqsave(&ppp
->lock
, flags
);
449 /* Check HDLC header */
450 if (skb
->len
< sizeof(struct hdlc_header
))
452 cp
= (struct cp_header
*)skb_pull(skb
, sizeof(struct hdlc_header
));
453 if (hdr
->address
!= HDLC_ADDR_ALLSTATIONS
||
454 hdr
->control
!= HDLC_CTRL_UI
)
457 pid
= ntohs(hdr
->protocol
);
458 proto
= get_proto(dev
, pid
);
460 if (ppp
->protos
[IDX_LCP
].state
== OPENED
)
461 ppp_tx_cp(dev
, PID_LCP
, LCP_PROTO_REJ
,
462 ++ppp
->seq
, skb
->len
+ 2, &hdr
->protocol
);
466 len
= ntohs(cp
->len
);
467 if (len
< sizeof(struct cp_header
) /* no complete CP header? */ ||
468 skb
->len
< len
/* truncated packet? */)
470 skb_pull(skb
, sizeof(struct cp_header
));
471 len
-= sizeof(struct cp_header
);
473 /* HDLC and CP headers stripped from skb */
475 if (cp
->code
< CP_CODES
)
476 sprintf(debug_buffer
, "[%s id 0x%X]", code_names
[cp
->code
],
479 sprintf(debug_buffer
, "[code %u id 0x%X]", cp
->code
, cp
->id
);
480 ptr
= debug_buffer
+ strlen(debug_buffer
);
481 for (i
= 0; i
< min_t(unsigned int, len
, DEBUG_CP
); i
++) {
482 sprintf(ptr
, " %02X", skb
->data
[i
]);
485 printk(KERN_DEBUG
"%s: RX %s %s\n", dev
->name
, proto_name(pid
),
493 pid
= ntohs(*(__be16
*)skb
->data
);
494 if (pid
== PID_LCP
|| pid
== PID_IPCP
||
496 ppp_cp_event(dev
, pid
, RXJ_BAD
, 0, 0,
500 case LCP_ECHO_REQ
: /* send Echo-Reply */
501 if (len
>= 4 && proto
->state
== OPENED
)
502 ppp_tx_cp(dev
, PID_LCP
, LCP_ECHO_REPLY
,
503 cp
->id
, len
- 4, skb
->data
+ 4);
507 if (cp
->id
== ppp
->echo_id
)
508 ppp
->last_pong
= jiffies
;
511 case LCP_DISC_REQ
: /* discard */
515 /* LCP, IPCP and IPV6CP */
518 ppp_cp_parse_cr(dev
, pid
, cp
->id
, len
, skb
->data
);
522 if (cp
->id
== proto
->cr_id
)
523 ppp_cp_event(dev
, pid
, RCA
, 0, 0, 0, NULL
);
528 if (cp
->id
== proto
->cr_id
)
529 ppp_cp_event(dev
, pid
, RCN
, 0, 0, 0, NULL
);
533 ppp_cp_event(dev
, pid
, RTR
, 0, cp
->id
, 0, NULL
);
537 ppp_cp_event(dev
, pid
, RTA
, 0, 0, 0, NULL
);
541 ppp_cp_event(dev
, pid
, RXJ_BAD
, 0, 0, 0, NULL
);
545 len
+= sizeof(struct cp_header
);
548 ppp_cp_event(dev
, pid
, RUC
, 0, 0, len
, cp
);
554 dev
->stats
.rx_errors
++;
556 spin_unlock_irqrestore(&ppp
->lock
, flags
);
557 dev_kfree_skb_any(skb
);
562 static void ppp_timer(unsigned long arg
)
564 struct proto
*proto
= (struct proto
*)arg
;
565 struct ppp
*ppp
= get_ppp(proto
->dev
);
568 spin_lock_irqsave(&ppp
->lock
, flags
);
569 switch (proto
->state
) {
574 if (proto
->restart_counter
) {
575 ppp_cp_event(proto
->dev
, proto
->pid
, TO_GOOD
, 0, 0,
577 proto
->restart_counter
--;
579 ppp_cp_event(proto
->dev
, proto
->pid
, TO_BAD
, 0, 0,
584 if (proto
->pid
!= PID_LCP
)
586 if (time_after(jiffies
, ppp
->last_pong
+
587 ppp
->keepalive_timeout
* HZ
)) {
588 printk(KERN_INFO
"%s: Link down\n", proto
->dev
->name
);
589 ppp_cp_event(proto
->dev
, PID_LCP
, STOP
, 0, 0, 0, NULL
);
590 ppp_cp_event(proto
->dev
, PID_LCP
, START
, 0, 0, 0, NULL
);
591 } else { /* send keep-alive packet */
592 ppp
->echo_id
= ++ppp
->seq
;
593 ppp_tx_cp(proto
->dev
, PID_LCP
, LCP_ECHO_REQ
,
594 ppp
->echo_id
, 0, NULL
);
595 proto
->timer
.expires
= jiffies
+
596 ppp
->keepalive_interval
* HZ
;
597 add_timer(&proto
->timer
);
601 spin_unlock_irqrestore(&ppp
->lock
, flags
);
606 static void ppp_start(struct net_device
*dev
)
608 struct ppp
*ppp
= get_ppp(dev
);
611 for (i
= 0; i
< IDX_COUNT
; i
++) {
612 struct proto
*proto
= &ppp
->protos
[i
];
614 init_timer(&proto
->timer
);
615 proto
->timer
.function
= ppp_timer
;
616 proto
->timer
.data
= (unsigned long)proto
;
617 proto
->state
= CLOSED
;
619 ppp
->protos
[IDX_LCP
].pid
= PID_LCP
;
620 ppp
->protos
[IDX_IPCP
].pid
= PID_IPCP
;
621 ppp
->protos
[IDX_IPV6CP
].pid
= PID_IPV6CP
;
623 ppp_cp_event(dev
, PID_LCP
, START
, 0, 0, 0, NULL
);
626 static void ppp_stop(struct net_device
*dev
)
628 ppp_cp_event(dev
, PID_LCP
, STOP
, 0, 0, 0, NULL
);
631 static struct hdlc_proto proto
= {
634 .type_trans
= ppp_type_trans
,
637 .module
= THIS_MODULE
,
640 static const struct header_ops ppp_header_ops
= {
641 .create
= ppp_hard_header
,
644 static int ppp_ioctl(struct net_device
*dev
, struct ifreq
*ifr
)
646 hdlc_device
*hdlc
= dev_to_hdlc(dev
);
650 switch (ifr
->ifr_settings
.type
) {
652 if (dev_to_hdlc(dev
)->proto
!= &proto
)
654 ifr
->ifr_settings
.type
= IF_PROTO_PPP
;
655 return 0; /* return protocol only, no settable parameters */
658 if (!capable(CAP_NET_ADMIN
))
661 if (dev
->flags
& IFF_UP
)
664 /* no settable parameters */
666 result
= hdlc
->attach(dev
, ENCODING_NRZ
,PARITY_CRC16_PR1_CCITT
);
670 result
= attach_hdlc_protocol(dev
, &proto
, sizeof(struct ppp
));
675 spin_lock_init(&ppp
->lock
);
676 ppp
->req_timeout
= 2;
677 ppp
->cr_retries
= 10;
678 ppp
->term_retries
= 2;
679 ppp
->keepalive_interval
= 10;
680 ppp
->keepalive_timeout
= 60;
682 dev
->hard_header_len
= sizeof(struct hdlc_header
);
683 dev
->header_ops
= &ppp_header_ops
;
684 dev
->type
= ARPHRD_PPP
;
685 netif_dormant_on(dev
);
693 static int __init
mod_init(void)
695 skb_queue_head_init(&tx_queue
);
696 register_hdlc_protocol(&proto
);
700 static void __exit
mod_exit(void)
702 unregister_hdlc_protocol(&proto
);
706 module_init(mod_init
);
707 module_exit(mod_exit
);
709 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
710 MODULE_DESCRIPTION("PPP protocol support for generic HDLC");
711 MODULE_LICENSE("GPL v2");