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1#ifndef _DCCP_H
2#define _DCCP_H
3/*
4 * net/dccp/dccp.h
5 *
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>
9 *
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.
13 */
14
15#include <linux/dccp.h>
16#include <linux/ktime.h>
17#include <net/snmp.h>
18#include <net/sock.h>
19#include <net/tcp.h>
20#include "ackvec.h"
21
22/*
23 * DCCP - specific warning and debugging macros.
24 */
25#define DCCP_WARN(fmt, a...) LIMIT_NETDEBUG(KERN_WARNING "%s: " fmt, \
26 __func__, ##a)
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!)", \
32 __stringify(cond)); \
33 } while (0)
34
35#define DCCP_PRINTK(enable, fmt, args...) do { if (enable) \
36 printk(fmt, ##args); \
37 } while(0)
38#define DCCP_PR_DEBUG(enable, fmt, a...) DCCP_PRINTK(enable, KERN_DEBUG \
39 "%s: " fmt, __func__, ##a)
40
41#ifdef CONFIG_IP_DCCP_DEBUG
42extern 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#else
46#define dccp_pr_debug(format, a...)
47#define dccp_pr_debug_cat(format, a...)
48#endif
49
50extern struct inet_hashinfo dccp_hashinfo;
51
52extern atomic_t dccp_orphan_count;
53
54extern void dccp_time_wait(struct sock *sk, int state, int timeo);
55
56/*
57 * Set safe upper bounds for header and option length. Since Data Offset is 8
58 * bits (RFC 4340, sec. 5.1), the total header length can never be more than
59 * 4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1):
60 * - DCCP-Response with ACK Subheader and 4 bytes of Service code OR
61 * - DCCP-Reset with ACK Subheader and 4 bytes of Reset Code fields
62 * Hence a safe upper bound for the maximum option length is 1020-28 = 992
63 */
64#define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(int))
65#define DCCP_MAX_PACKET_HDR 28
66#define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR)
67#define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER)
68
69#define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
70 * state, about 60 seconds */
71
72/* RFC 1122, 4.2.3.1 initial RTO value */
73#define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))
74
75/*
76 * The maximum back-off value for retransmissions. This is needed for
77 * - retransmitting client-Requests (sec. 8.1.1),
78 * - retransmitting Close/CloseReq when closing (sec. 8.3),
79 * - feature-negotiation retransmission (sec. 6.6.3),
80 * - Acks in client-PARTOPEN state (sec. 8.1.5).
81 */
82#define DCCP_RTO_MAX ((unsigned)(64 * HZ))
83
84/*
85 * RTT sampling: sanity bounds and fallback RTT value from RFC 4340, section 3.4
86 */
87#define DCCP_SANE_RTT_MIN 100
88#define DCCP_FALLBACK_RTT (USEC_PER_SEC / 5)
89#define DCCP_SANE_RTT_MAX (3 * USEC_PER_SEC)
90
91/* Maximal interval between probes for local resources. */
92#define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))
93
94/* sysctl variables for DCCP */
95extern int sysctl_dccp_request_retries;
96extern int sysctl_dccp_retries1;
97extern int sysctl_dccp_retries2;
98extern int sysctl_dccp_feat_sequence_window;
99extern int sysctl_dccp_feat_rx_ccid;
100extern int sysctl_dccp_feat_tx_ccid;
101extern int sysctl_dccp_feat_ack_ratio;
102extern int sysctl_dccp_feat_send_ack_vector;
103extern int sysctl_dccp_feat_send_ndp_count;
104extern int sysctl_dccp_tx_qlen;
105extern int sysctl_dccp_sync_ratelimit;
106
107/*
108 * 48-bit sequence number arithmetic (signed and unsigned)
109 */
110#define INT48_MIN 0x800000000000LL /* 2^47 */
111#define UINT48_MAX 0xFFFFFFFFFFFFLL /* 2^48 - 1 */
112#define COMPLEMENT48(x) (0x1000000000000LL - (x)) /* 2^48 - x */
113#define TO_SIGNED48(x) (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x)))
114#define TO_UNSIGNED48(x) (((x) >= 0)? (x) : COMPLEMENT48(-(x)))
115#define ADD48(a, b) (((a) + (b)) & UINT48_MAX)
116#define SUB48(a, b) ADD48((a), COMPLEMENT48(b))
117
118static inline void dccp_set_seqno(u64 *seqno, u64 value)
119{
120 *seqno = value & UINT48_MAX;
121}
122
123static inline void dccp_inc_seqno(u64 *seqno)
124{
125 *seqno = ADD48(*seqno, 1);
126}
127
128/* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
129static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
130{
131 u64 delta = SUB48(seqno2, seqno1);
132
133 return TO_SIGNED48(delta);
134}
135
136/* is seq1 < seq2 ? */
137static inline int before48(const u64 seq1, const u64 seq2)
138{
139 return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
140}
141
142/* is seq1 > seq2 ? */
143#define after48(seq1, seq2) before48(seq2, seq1)
144
145/* is seq2 <= seq1 <= seq3 ? */
146static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
147{
148 return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
149}
150
151static inline u64 max48(const u64 seq1, const u64 seq2)
152{
153 return after48(seq1, seq2) ? seq1 : seq2;
154}
155
156enum {
157 DCCP_MIB_NUM = 0,
158 DCCP_MIB_ACTIVEOPENS, /* ActiveOpens */
159 DCCP_MIB_ESTABRESETS, /* EstabResets */
160 DCCP_MIB_CURRESTAB, /* CurrEstab */
161 DCCP_MIB_OUTSEGS, /* OutSegs */
162 DCCP_MIB_OUTRSTS,
163 DCCP_MIB_ABORTONTIMEOUT,
164 DCCP_MIB_TIMEOUTS,
165 DCCP_MIB_ABORTFAILED,
166 DCCP_MIB_PASSIVEOPENS,
167 DCCP_MIB_ATTEMPTFAILS,
168 DCCP_MIB_OUTDATAGRAMS,
169 DCCP_MIB_INERRS,
170 DCCP_MIB_OPTMANDATORYERROR,
171 DCCP_MIB_INVALIDOPT,
172 __DCCP_MIB_MAX
173};
174
175#define DCCP_MIB_MAX __DCCP_MIB_MAX
176struct dccp_mib {
177 unsigned long mibs[DCCP_MIB_MAX];
178} __SNMP_MIB_ALIGN__;
179
180DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
181#define DCCP_INC_STATS(field) SNMP_INC_STATS(dccp_statistics, field)
182#define DCCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(dccp_statistics, field)
183#define DCCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(dccp_statistics, field)
184#define DCCP_DEC_STATS(field) SNMP_DEC_STATS(dccp_statistics, field)
185#define DCCP_ADD_STATS_BH(field, val) \
186 SNMP_ADD_STATS_BH(dccp_statistics, field, val)
187#define DCCP_ADD_STATS_USER(field, val) \
188 SNMP_ADD_STATS_USER(dccp_statistics, field, val)
189
190/*
191 * Checksumming routines
192 */
193static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb)
194{
195 const struct dccp_hdr* dh = dccp_hdr(skb);
196
197 if (dh->dccph_cscov == 0)
198 return skb->len;
199 return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
200}
201
202static inline void dccp_csum_outgoing(struct sk_buff *skb)
203{
204 unsigned int cov = dccp_csum_coverage(skb);
205
206 if (cov >= skb->len)
207 dccp_hdr(skb)->dccph_cscov = 0;
208
209 skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
210}
211
212extern void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
213
214extern int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb);
215
216extern void dccp_send_ack(struct sock *sk);
217extern void dccp_reqsk_send_ack(struct sk_buff *sk, struct request_sock *rsk);
218
219extern void dccp_send_sync(struct sock *sk, const u64 seq,
220 const enum dccp_pkt_type pkt_type);
221
222extern void dccp_write_xmit(struct sock *sk, int block);
223extern void dccp_write_space(struct sock *sk);
224
225extern void dccp_init_xmit_timers(struct sock *sk);
226static inline void dccp_clear_xmit_timers(struct sock *sk)
227{
228 inet_csk_clear_xmit_timers(sk);
229}
230
231extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
232
233extern const char *dccp_packet_name(const int type);
234extern const char *dccp_state_name(const int state);
235
236extern void dccp_set_state(struct sock *sk, const int state);
237extern void dccp_done(struct sock *sk);
238
239extern void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb);
240
241extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
242
243extern struct sock *dccp_create_openreq_child(struct sock *sk,
244 const struct request_sock *req,
245 const struct sk_buff *skb);
246
247extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
248
249extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
250 struct sk_buff *skb,
251 struct request_sock *req,
252 struct dst_entry *dst);
253extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
254 struct request_sock *req,
255 struct request_sock **prev);
256
257extern int dccp_child_process(struct sock *parent, struct sock *child,
258 struct sk_buff *skb);
259extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
260 struct dccp_hdr *dh, unsigned len);
261extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
262 const struct dccp_hdr *dh, const unsigned len);
263
264extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
265extern int dccp_destroy_sock(struct sock *sk);
266
267extern void dccp_close(struct sock *sk, long timeout);
268extern struct sk_buff *dccp_make_response(struct sock *sk,
269 struct dst_entry *dst,
270 struct request_sock *req);
271
272extern int dccp_connect(struct sock *sk);
273extern int dccp_disconnect(struct sock *sk, int flags);
274extern int dccp_getsockopt(struct sock *sk, int level, int optname,
275 char __user *optval, int __user *optlen);
276extern int dccp_setsockopt(struct sock *sk, int level, int optname,
277 char __user *optval, int optlen);
278#ifdef CONFIG_COMPAT
279extern int compat_dccp_getsockopt(struct sock *sk,
280 int level, int optname,
281 char __user *optval, int __user *optlen);
282extern int compat_dccp_setsockopt(struct sock *sk,
283 int level, int optname,
284 char __user *optval, int optlen);
285#endif
286extern int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
287extern int dccp_sendmsg(struct kiocb *iocb, struct sock *sk,
288 struct msghdr *msg, size_t size);
289extern int dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
290 struct msghdr *msg, size_t len, int nonblock,
291 int flags, int *addr_len);
292extern void dccp_shutdown(struct sock *sk, int how);
293extern int inet_dccp_listen(struct socket *sock, int backlog);
294extern unsigned int dccp_poll(struct file *file, struct socket *sock,
295 poll_table *wait);
296extern int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
297 int addr_len);
298
299extern struct sk_buff *dccp_ctl_make_reset(struct sock *sk,
300 struct sk_buff *skb);
301extern int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
302extern void dccp_send_close(struct sock *sk, const int active);
303extern int dccp_invalid_packet(struct sk_buff *skb);
304extern u32 dccp_sample_rtt(struct sock *sk, long delta);
305
306static inline int dccp_bad_service_code(const struct sock *sk,
307 const __be32 service)
308{
309 const struct dccp_sock *dp = dccp_sk(sk);
310
311 if (dp->dccps_service == service)
312 return 0;
313 return !dccp_list_has_service(dp->dccps_service_list, service);
314}
315
316/**
317 * dccp_skb_cb - DCCP per-packet control information
318 * @dccpd_type: one of %dccp_pkt_type (or unknown)
319 * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1
320 * @dccpd_reset_code: one of %dccp_reset_codes
321 * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code)
322 * @dccpd_opt_len: total length of all options (5.8) in the packet
323 * @dccpd_seq: sequence number
324 * @dccpd_ack_seq: acknowledgment number subheader field value
325 * This is used for transmission as well as for reception.
326 */
327struct dccp_skb_cb {
328 union {
329 struct inet_skb_parm h4;
330#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
331 struct inet6_skb_parm h6;
332#endif
333 } header;
334 __u8 dccpd_type:4;
335 __u8 dccpd_ccval:4;
336 __u8 dccpd_reset_code,
337 dccpd_reset_data[3];
338 __u16 dccpd_opt_len;
339 __u64 dccpd_seq;
340 __u64 dccpd_ack_seq;
341};
342
343#define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
344
345/* RFC 4340, sec. 7.7 */
346static inline int dccp_non_data_packet(const struct sk_buff *skb)
347{
348 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
349
350 return type == DCCP_PKT_ACK ||
351 type == DCCP_PKT_CLOSE ||
352 type == DCCP_PKT_CLOSEREQ ||
353 type == DCCP_PKT_RESET ||
354 type == DCCP_PKT_SYNC ||
355 type == DCCP_PKT_SYNCACK;
356}
357
358/* RFC 4340, sec. 7.7 */
359static inline int dccp_data_packet(const struct sk_buff *skb)
360{
361 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
362
363 return type == DCCP_PKT_DATA ||
364 type == DCCP_PKT_DATAACK ||
365 type == DCCP_PKT_REQUEST ||
366 type == DCCP_PKT_RESPONSE;
367}
368
369static inline int dccp_packet_without_ack(const struct sk_buff *skb)
370{
371 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
372
373 return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
374}
375
376#define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
377
378static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
379{
380 struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
381 sizeof(*dh));
382 dh->dccph_seq2 = 0;
383 dh->dccph_seq = htons((gss >> 32) & 0xfffff);
384 dhx->dccph_seq_low = htonl(gss & 0xffffffff);
385}
386
387static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
388 const u64 gsr)
389{
390 dhack->dccph_reserved1 = 0;
391 dhack->dccph_ack_nr_high = htons(gsr >> 32);
392 dhack->dccph_ack_nr_low = htonl(gsr & 0xffffffff);
393}
394
395static inline void dccp_update_gsr(struct sock *sk, u64 seq)
396{
397 struct dccp_sock *dp = dccp_sk(sk);
398 const struct dccp_minisock *dmsk = dccp_msk(sk);
399
400 dp->dccps_gsr = seq;
401 dccp_set_seqno(&dp->dccps_swl,
402 dp->dccps_gsr + 1 - (dmsk->dccpms_sequence_window / 4));
403 dccp_set_seqno(&dp->dccps_swh,
404 dp->dccps_gsr + (3 * dmsk->dccpms_sequence_window) / 4);
405}
406
407static inline void dccp_update_gss(struct sock *sk, u64 seq)
408{
409 struct dccp_sock *dp = dccp_sk(sk);
410
411 dp->dccps_awh = dp->dccps_gss = seq;
412 dccp_set_seqno(&dp->dccps_awl,
413 (dp->dccps_gss -
414 dccp_msk(sk)->dccpms_sequence_window + 1));
415}
416
417static inline int dccp_ack_pending(const struct sock *sk)
418{
419 const struct dccp_sock *dp = dccp_sk(sk);
420 return dp->dccps_timestamp_echo != 0 ||
421#ifdef CONFIG_IP_DCCP_ACKVEC
422 (dccp_msk(sk)->dccpms_send_ack_vector &&
423 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
424#endif
425 inet_csk_ack_scheduled(sk);
426}
427
428extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
429extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);
430extern int dccp_insert_option_elapsed_time(struct sock *sk,
431 struct sk_buff *skb,
432 u32 elapsed_time);
433extern u32 dccp_timestamp(void);
434extern void dccp_timestamping_init(void);
435extern int dccp_insert_option_timestamp(struct sock *sk,
436 struct sk_buff *skb);
437extern int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
438 unsigned char option,
439 const void *value, unsigned char len);
440
441#ifdef CONFIG_SYSCTL
442extern int dccp_sysctl_init(void);
443extern void dccp_sysctl_exit(void);
444#else
445static inline int dccp_sysctl_init(void)
446{
447 return 0;
448}
449
450static inline void dccp_sysctl_exit(void)
451{
452}
453#endif
454
455#endif /* _DCCP_H */