6 * An implementation of the DCCP protocol
7 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
8 * Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
15 #include <linux/dccp.h>
16 #include <linux/ktime.h>
23 * DCCP - specific warning and debugging macros.
25 #define DCCP_WARN(fmt, a...) LIMIT_NETDEBUG(KERN_WARNING "%s: " fmt, \
27 #define DCCP_CRIT(fmt, a...) printk(KERN_CRIT fmt " at %s:%d/%s()\n", ##a, \
28 __FILE__, __LINE__, __func__)
29 #define DCCP_BUG(a...) do { DCCP_CRIT("BUG: " a); dump_stack(); } while(0)
30 #define DCCP_BUG_ON(cond) do { if (unlikely((cond) != 0)) \
31 DCCP_BUG("\"%s\" holds (exception!)", \
35 #define DCCP_PRINTK(enable, fmt, args...) do { if (enable) \
36 printk(fmt, ##args); \
38 #define DCCP_PR_DEBUG(enable, fmt, a...) DCCP_PRINTK(enable, KERN_DEBUG \
39 "%s: " fmt, __func__, ##a)
41 #ifdef CONFIG_IP_DCCP_DEBUG
42 extern int dccp_debug
;
43 #define dccp_pr_debug(format, a...) DCCP_PR_DEBUG(dccp_debug, format, ##a)
44 #define dccp_pr_debug_cat(format, a...) DCCP_PRINTK(dccp_debug, format, ##a)
45 #define dccp_debug(fmt, a...) dccp_pr_debug_cat(KERN_DEBUG fmt, ##a)
47 #define dccp_pr_debug(format, a...)
48 #define dccp_pr_debug_cat(format, a...)
49 #define dccp_debug(format, a...)
52 extern struct inet_hashinfo dccp_hashinfo
;
54 extern struct percpu_counter dccp_orphan_count
;
56 extern void dccp_time_wait(struct sock
*sk
, int state
, int timeo
);
59 * Set safe upper bounds for header and option length. Since Data Offset is 8
60 * bits (RFC 4340, sec. 5.1), the total header length can never be more than
61 * 4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1):
62 * - DCCP-Response with ACK Subheader and 4 bytes of Service code OR
63 * - DCCP-Reset with ACK Subheader and 4 bytes of Reset Code fields
64 * Hence a safe upper bound for the maximum option length is 1020-28 = 992
66 #define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(uint32_t))
67 #define DCCP_MAX_PACKET_HDR 28
68 #define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR)
69 #define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER)
71 /* Upper bound for initial feature-negotiation overhead (padded to 32 bits) */
72 #define DCCP_FEATNEG_OVERHEAD (32 * sizeof(uint32_t))
74 #define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
75 * state, about 60 seconds */
77 /* RFC 1122, 4.2.3.1 initial RTO value */
78 #define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))
81 * The maximum back-off value for retransmissions. This is needed for
82 * - retransmitting client-Requests (sec. 8.1.1),
83 * - retransmitting Close/CloseReq when closing (sec. 8.3),
84 * - feature-negotiation retransmission (sec. 6.6.3),
85 * - Acks in client-PARTOPEN state (sec. 8.1.5).
87 #define DCCP_RTO_MAX ((unsigned)(64 * HZ))
90 * RTT sampling: sanity bounds and fallback RTT value from RFC 4340, section 3.4
92 #define DCCP_SANE_RTT_MIN 100
93 #define DCCP_FALLBACK_RTT (USEC_PER_SEC / 5)
94 #define DCCP_SANE_RTT_MAX (3 * USEC_PER_SEC)
96 /* Maximal interval between probes for local resources. */
97 #define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))
99 /* sysctl variables for DCCP */
100 extern int sysctl_dccp_request_retries
;
101 extern int sysctl_dccp_retries1
;
102 extern int sysctl_dccp_retries2
;
103 extern int sysctl_dccp_tx_qlen
;
104 extern int sysctl_dccp_sync_ratelimit
;
107 * 48-bit sequence number arithmetic (signed and unsigned)
109 #define INT48_MIN 0x800000000000LL /* 2^47 */
110 #define UINT48_MAX 0xFFFFFFFFFFFFLL /* 2^48 - 1 */
111 #define COMPLEMENT48(x) (0x1000000000000LL - (x)) /* 2^48 - x */
112 #define TO_SIGNED48(x) (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x)))
113 #define TO_UNSIGNED48(x) (((x) >= 0)? (x) : COMPLEMENT48(-(x)))
114 #define ADD48(a, b) (((a) + (b)) & UINT48_MAX)
115 #define SUB48(a, b) ADD48((a), COMPLEMENT48(b))
117 static inline void dccp_set_seqno(u64
*seqno
, u64 value
)
119 *seqno
= value
& UINT48_MAX
;
122 static inline void dccp_inc_seqno(u64
*seqno
)
124 *seqno
= ADD48(*seqno
, 1);
127 /* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
128 static inline s64
dccp_delta_seqno(const u64 seqno1
, const u64 seqno2
)
130 u64 delta
= SUB48(seqno2
, seqno1
);
132 return TO_SIGNED48(delta
);
135 /* is seq1 < seq2 ? */
136 static inline int before48(const u64 seq1
, const u64 seq2
)
138 return (s64
)((seq2
<< 16) - (seq1
<< 16)) > 0;
141 /* is seq1 > seq2 ? */
142 #define after48(seq1, seq2) before48(seq2, seq1)
144 /* is seq2 <= seq1 <= seq3 ? */
145 static inline int between48(const u64 seq1
, const u64 seq2
, const u64 seq3
)
147 return (seq3
<< 16) - (seq2
<< 16) >= (seq1
<< 16) - (seq2
<< 16);
150 static inline u64
max48(const u64 seq1
, const u64 seq2
)
152 return after48(seq1
, seq2
) ? seq1
: seq2
;
156 * dccp_loss_count - Approximate the number of lost data packets in a burst loss
157 * @s1: last known sequence number before the loss ('hole')
158 * @s2: first sequence number seen after the 'hole'
159 * @ndp: NDP count on packet with sequence number @s2
161 static inline u64
dccp_loss_count(const u64 s1
, const u64 s2
, const u64 ndp
)
163 s64 delta
= dccp_delta_seqno(s1
, s2
);
168 return delta
> 0 ? delta
: 0;
172 * dccp_loss_free - Evaluate condition for data loss from RFC 4340, 7.7.1
174 static inline bool dccp_loss_free(const u64 s1
, const u64 s2
, const u64 ndp
)
176 return dccp_loss_count(s1
, s2
, ndp
) == 0;
181 DCCP_MIB_ACTIVEOPENS
, /* ActiveOpens */
182 DCCP_MIB_ESTABRESETS
, /* EstabResets */
183 DCCP_MIB_CURRESTAB
, /* CurrEstab */
184 DCCP_MIB_OUTSEGS
, /* OutSegs */
186 DCCP_MIB_ABORTONTIMEOUT
,
188 DCCP_MIB_ABORTFAILED
,
189 DCCP_MIB_PASSIVEOPENS
,
190 DCCP_MIB_ATTEMPTFAILS
,
191 DCCP_MIB_OUTDATAGRAMS
,
193 DCCP_MIB_OPTMANDATORYERROR
,
198 #define DCCP_MIB_MAX __DCCP_MIB_MAX
200 unsigned long mibs
[DCCP_MIB_MAX
];
203 DECLARE_SNMP_STAT(struct dccp_mib
, dccp_statistics
);
204 #define DCCP_INC_STATS(field) SNMP_INC_STATS(dccp_statistics, field)
205 #define DCCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(dccp_statistics, field)
206 #define DCCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(dccp_statistics, field)
207 #define DCCP_DEC_STATS(field) SNMP_DEC_STATS(dccp_statistics, field)
208 #define DCCP_ADD_STATS_BH(field, val) \
209 SNMP_ADD_STATS_BH(dccp_statistics, field, val)
210 #define DCCP_ADD_STATS_USER(field, val) \
211 SNMP_ADD_STATS_USER(dccp_statistics, field, val)
214 * Checksumming routines
216 static inline unsigned int dccp_csum_coverage(const struct sk_buff
*skb
)
218 const struct dccp_hdr
* dh
= dccp_hdr(skb
);
220 if (dh
->dccph_cscov
== 0)
222 return (dh
->dccph_doff
+ dh
->dccph_cscov
- 1) * sizeof(u32
);
225 static inline void dccp_csum_outgoing(struct sk_buff
*skb
)
227 unsigned int cov
= dccp_csum_coverage(skb
);
230 dccp_hdr(skb
)->dccph_cscov
= 0;
232 skb
->csum
= skb_checksum(skb
, 0, (cov
> skb
->len
)? skb
->len
: cov
, 0);
235 extern void dccp_v4_send_check(struct sock
*sk
, struct sk_buff
*skb
);
237 extern int dccp_retransmit_skb(struct sock
*sk
);
239 extern void dccp_send_ack(struct sock
*sk
);
240 extern void dccp_reqsk_send_ack(struct sock
*sk
, struct sk_buff
*skb
,
241 struct request_sock
*rsk
);
243 extern void dccp_send_sync(struct sock
*sk
, const u64 seq
,
244 const enum dccp_pkt_type pkt_type
);
247 * TX Packet Dequeueing Interface
249 extern void dccp_qpolicy_push(struct sock
*sk
, struct sk_buff
*skb
);
250 extern bool dccp_qpolicy_full(struct sock
*sk
);
251 extern void dccp_qpolicy_drop(struct sock
*sk
, struct sk_buff
*skb
);
252 extern struct sk_buff
*dccp_qpolicy_top(struct sock
*sk
);
253 extern struct sk_buff
*dccp_qpolicy_pop(struct sock
*sk
);
254 extern bool dccp_qpolicy_param_ok(struct sock
*sk
, __be32 param
);
257 * TX Packet Output and TX Timers
259 extern void dccp_write_xmit(struct sock
*sk
);
260 extern void dccp_write_space(struct sock
*sk
);
261 extern void dccp_flush_write_queue(struct sock
*sk
, long *time_budget
);
263 extern void dccp_init_xmit_timers(struct sock
*sk
);
264 static inline void dccp_clear_xmit_timers(struct sock
*sk
)
266 inet_csk_clear_xmit_timers(sk
);
269 extern unsigned int dccp_sync_mss(struct sock
*sk
, u32 pmtu
);
271 extern const char *dccp_packet_name(const int type
);
273 extern void dccp_set_state(struct sock
*sk
, const int state
);
274 extern void dccp_done(struct sock
*sk
);
276 extern int dccp_reqsk_init(struct request_sock
*rq
, struct dccp_sock
const *dp
,
277 struct sk_buff
const *skb
);
279 extern int dccp_v4_conn_request(struct sock
*sk
, struct sk_buff
*skb
);
281 extern struct sock
*dccp_create_openreq_child(struct sock
*sk
,
282 const struct request_sock
*req
,
283 const struct sk_buff
*skb
);
285 extern int dccp_v4_do_rcv(struct sock
*sk
, struct sk_buff
*skb
);
287 extern struct sock
*dccp_v4_request_recv_sock(struct sock
*sk
,
289 struct request_sock
*req
,
290 struct dst_entry
*dst
);
291 extern struct sock
*dccp_check_req(struct sock
*sk
, struct sk_buff
*skb
,
292 struct request_sock
*req
,
293 struct request_sock
**prev
);
295 extern int dccp_child_process(struct sock
*parent
, struct sock
*child
,
296 struct sk_buff
*skb
);
297 extern int dccp_rcv_state_process(struct sock
*sk
, struct sk_buff
*skb
,
298 struct dccp_hdr
*dh
, unsigned len
);
299 extern int dccp_rcv_established(struct sock
*sk
, struct sk_buff
*skb
,
300 const struct dccp_hdr
*dh
, const unsigned len
);
302 extern int dccp_init_sock(struct sock
*sk
, const __u8 ctl_sock_initialized
);
303 extern void dccp_destroy_sock(struct sock
*sk
);
305 extern void dccp_close(struct sock
*sk
, long timeout
);
306 extern struct sk_buff
*dccp_make_response(struct sock
*sk
,
307 struct dst_entry
*dst
,
308 struct request_sock
*req
);
310 extern int dccp_connect(struct sock
*sk
);
311 extern int dccp_disconnect(struct sock
*sk
, int flags
);
312 extern int dccp_getsockopt(struct sock
*sk
, int level
, int optname
,
313 char __user
*optval
, int __user
*optlen
);
314 extern int dccp_setsockopt(struct sock
*sk
, int level
, int optname
,
315 char __user
*optval
, unsigned int optlen
);
317 extern int compat_dccp_getsockopt(struct sock
*sk
,
318 int level
, int optname
,
319 char __user
*optval
, int __user
*optlen
);
320 extern int compat_dccp_setsockopt(struct sock
*sk
,
321 int level
, int optname
,
322 char __user
*optval
, unsigned int optlen
);
324 extern int dccp_ioctl(struct sock
*sk
, int cmd
, unsigned long arg
);
325 extern int dccp_sendmsg(struct kiocb
*iocb
, struct sock
*sk
,
326 struct msghdr
*msg
, size_t size
);
327 extern int dccp_recvmsg(struct kiocb
*iocb
, struct sock
*sk
,
328 struct msghdr
*msg
, size_t len
, int nonblock
,
329 int flags
, int *addr_len
);
330 extern void dccp_shutdown(struct sock
*sk
, int how
);
331 extern int inet_dccp_listen(struct socket
*sock
, int backlog
);
332 extern unsigned int dccp_poll(struct file
*file
, struct socket
*sock
,
334 extern int dccp_v4_connect(struct sock
*sk
, struct sockaddr
*uaddr
,
337 extern struct sk_buff
*dccp_ctl_make_reset(struct sock
*sk
,
338 struct sk_buff
*skb
);
339 extern int dccp_send_reset(struct sock
*sk
, enum dccp_reset_codes code
);
340 extern void dccp_send_close(struct sock
*sk
, const int active
);
341 extern int dccp_invalid_packet(struct sk_buff
*skb
);
342 extern u32
dccp_sample_rtt(struct sock
*sk
, long delta
);
344 static inline int dccp_bad_service_code(const struct sock
*sk
,
345 const __be32 service
)
347 const struct dccp_sock
*dp
= dccp_sk(sk
);
349 if (dp
->dccps_service
== service
)
351 return !dccp_list_has_service(dp
->dccps_service_list
, service
);
355 * dccp_skb_cb - DCCP per-packet control information
356 * @dccpd_type: one of %dccp_pkt_type (or unknown)
357 * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1
358 * @dccpd_reset_code: one of %dccp_reset_codes
359 * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code)
360 * @dccpd_opt_len: total length of all options (5.8) in the packet
361 * @dccpd_seq: sequence number
362 * @dccpd_ack_seq: acknowledgment number subheader field value
363 * This is used for transmission as well as for reception.
367 struct inet_skb_parm h4
;
368 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
369 struct inet6_skb_parm h6
;
374 __u8 dccpd_reset_code
,
381 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
383 /* RFC 4340, sec. 7.7 */
384 static inline int dccp_non_data_packet(const struct sk_buff
*skb
)
386 const __u8 type
= DCCP_SKB_CB(skb
)->dccpd_type
;
388 return type
== DCCP_PKT_ACK
||
389 type
== DCCP_PKT_CLOSE
||
390 type
== DCCP_PKT_CLOSEREQ
||
391 type
== DCCP_PKT_RESET
||
392 type
== DCCP_PKT_SYNC
||
393 type
== DCCP_PKT_SYNCACK
;
396 /* RFC 4340, sec. 7.7 */
397 static inline int dccp_data_packet(const struct sk_buff
*skb
)
399 const __u8 type
= DCCP_SKB_CB(skb
)->dccpd_type
;
401 return type
== DCCP_PKT_DATA
||
402 type
== DCCP_PKT_DATAACK
||
403 type
== DCCP_PKT_REQUEST
||
404 type
== DCCP_PKT_RESPONSE
;
407 static inline int dccp_packet_without_ack(const struct sk_buff
*skb
)
409 const __u8 type
= DCCP_SKB_CB(skb
)->dccpd_type
;
411 return type
== DCCP_PKT_DATA
|| type
== DCCP_PKT_REQUEST
;
414 #define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
416 static inline void dccp_hdr_set_seq(struct dccp_hdr
*dh
, const u64 gss
)
418 struct dccp_hdr_ext
*dhx
= (struct dccp_hdr_ext
*)((void *)dh
+
421 dh
->dccph_seq
= htons((gss
>> 32) & 0xfffff);
422 dhx
->dccph_seq_low
= htonl(gss
& 0xffffffff);
425 static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits
*dhack
,
428 dhack
->dccph_reserved1
= 0;
429 dhack
->dccph_ack_nr_high
= htons(gsr
>> 32);
430 dhack
->dccph_ack_nr_low
= htonl(gsr
& 0xffffffff);
433 static inline void dccp_update_gsr(struct sock
*sk
, u64 seq
)
435 struct dccp_sock
*dp
= dccp_sk(sk
);
438 /* Sequence validity window depends on remote Sequence Window (7.5.1) */
439 dp
->dccps_swl
= SUB48(ADD48(dp
->dccps_gsr
, 1), dp
->dccps_r_seq_win
/ 4);
441 * Adjust SWL so that it is not below ISR. In contrast to RFC 4340,
442 * 7.5.1 we perform this check beyond the initial handshake: W/W' are
443 * always > 32, so for the first W/W' packets in the lifetime of a
444 * connection we always have to adjust SWL.
445 * A second reason why we are doing this is that the window depends on
446 * the feature-remote value of Sequence Window: nothing stops the peer
447 * from updating this value while we are busy adjusting SWL for the
448 * first W packets (we would have to count from scratch again then).
449 * Therefore it is safer to always make sure that the Sequence Window
450 * is not artificially extended by a peer who grows SWL downwards by
451 * continually updating the feature-remote Sequence-Window.
452 * If sequence numbers wrap it is bad luck. But that will take a while
453 * (48 bit), and this measure prevents Sequence-number attacks.
455 if (before48(dp
->dccps_swl
, dp
->dccps_isr
))
456 dp
->dccps_swl
= dp
->dccps_isr
;
457 dp
->dccps_swh
= ADD48(dp
->dccps_gsr
, (3 * dp
->dccps_r_seq_win
) / 4);
460 static inline void dccp_update_gss(struct sock
*sk
, u64 seq
)
462 struct dccp_sock
*dp
= dccp_sk(sk
);
465 /* Ack validity window depends on local Sequence Window value (7.5.1) */
466 dp
->dccps_awl
= SUB48(ADD48(dp
->dccps_gss
, 1), dp
->dccps_l_seq_win
);
467 /* Adjust AWL so that it is not below ISS - see comment above for SWL */
468 if (before48(dp
->dccps_awl
, dp
->dccps_iss
))
469 dp
->dccps_awl
= dp
->dccps_iss
;
470 dp
->dccps_awh
= dp
->dccps_gss
;
473 static inline int dccp_ackvec_pending(const struct sock
*sk
)
475 return dccp_sk(sk
)->dccps_hc_rx_ackvec
!= NULL
&&
476 !dccp_ackvec_is_empty(dccp_sk(sk
)->dccps_hc_rx_ackvec
);
479 static inline int dccp_ack_pending(const struct sock
*sk
)
481 return dccp_ackvec_pending(sk
) || inet_csk_ack_scheduled(sk
);
484 extern int dccp_feat_finalise_settings(struct dccp_sock
*dp
);
485 extern int dccp_feat_server_ccid_dependencies(struct dccp_request_sock
*dreq
);
486 extern int dccp_feat_insert_opts(struct dccp_sock
*, struct dccp_request_sock
*,
487 struct sk_buff
*skb
);
488 extern int dccp_feat_activate_values(struct sock
*sk
, struct list_head
*fn
);
489 extern void dccp_feat_list_purge(struct list_head
*fn_list
);
491 extern int dccp_insert_options(struct sock
*sk
, struct sk_buff
*skb
);
492 extern int dccp_insert_options_rsk(struct dccp_request_sock
*, struct sk_buff
*);
493 extern int dccp_insert_option_elapsed_time(struct sk_buff
*skb
, u32 elapsed
);
494 extern u32
dccp_timestamp(void);
495 extern void dccp_timestamping_init(void);
496 extern int dccp_insert_option(struct sk_buff
*skb
, unsigned char option
,
497 const void *value
, unsigned char len
);
500 extern int dccp_sysctl_init(void);
501 extern void dccp_sysctl_exit(void);
503 static inline int dccp_sysctl_init(void)
508 static inline void dccp_sysctl_exit(void)