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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#define dccp_debug(fmt, a...) dccp_pr_debug_cat(KERN_DEBUG fmt, ##a)
46#else
47#define dccp_pr_debug(format, a...)
48#define dccp_pr_debug_cat(format, a...)
49#define dccp_debug(format, a...)
50#endif
51
52extern struct inet_hashinfo dccp_hashinfo;
53
54extern struct percpu_counter dccp_orphan_count;
55
56extern void dccp_time_wait(struct sock *sk, int state, int timeo);
57
58/*
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
65 */
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)
70
71/* Upper bound for initial feature-negotiation overhead (padded to 32 bits) */
72#define DCCP_FEATNEG_OVERHEAD (32 * sizeof(uint32_t))
73
74#define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
75 * state, about 60 seconds */
76
77/* RFC 1122, 4.2.3.1 initial RTO value */
78#define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))
79
80/*
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).
86 */
87#define DCCP_RTO_MAX ((unsigned)(64 * HZ))
88
89/*
90 * RTT sampling: sanity bounds and fallback RTT value from RFC 4340, section 3.4
91 */
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)
95
96/* sysctl variables for DCCP */
97extern int sysctl_dccp_request_retries;
98extern int sysctl_dccp_retries1;
99extern int sysctl_dccp_retries2;
100extern int sysctl_dccp_tx_qlen;
101extern int sysctl_dccp_sync_ratelimit;
102
103/*
104 * 48-bit sequence number arithmetic (signed and unsigned)
105 */
106#define INT48_MIN 0x800000000000LL /* 2^47 */
107#define UINT48_MAX 0xFFFFFFFFFFFFLL /* 2^48 - 1 */
108#define COMPLEMENT48(x) (0x1000000000000LL - (x)) /* 2^48 - x */
109#define TO_SIGNED48(x) (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x)))
110#define TO_UNSIGNED48(x) (((x) >= 0)? (x) : COMPLEMENT48(-(x)))
111#define ADD48(a, b) (((a) + (b)) & UINT48_MAX)
112#define SUB48(a, b) ADD48((a), COMPLEMENT48(b))
113
114static inline void dccp_set_seqno(u64 *seqno, u64 value)
115{
116 *seqno = value & UINT48_MAX;
117}
118
119static inline void dccp_inc_seqno(u64 *seqno)
120{
121 *seqno = ADD48(*seqno, 1);
122}
123
124/* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
125static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
126{
127 u64 delta = SUB48(seqno2, seqno1);
128
129 return TO_SIGNED48(delta);
130}
131
132/* is seq1 < seq2 ? */
133static inline int before48(const u64 seq1, const u64 seq2)
134{
135 return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
136}
137
138/* is seq1 > seq2 ? */
139#define after48(seq1, seq2) before48(seq2, seq1)
140
141/* is seq2 <= seq1 <= seq3 ? */
142static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
143{
144 return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
145}
146
147static inline u64 max48(const u64 seq1, const u64 seq2)
148{
149 return after48(seq1, seq2) ? seq1 : seq2;
150}
151
152/**
153 * dccp_loss_count - Approximate the number of lost data packets in a burst loss
154 * @s1: last known sequence number before the loss ('hole')
155 * @s2: first sequence number seen after the 'hole'
156 * @ndp: NDP count on packet with sequence number @s2
157 */
158static inline u64 dccp_loss_count(const u64 s1, const u64 s2, const u64 ndp)
159{
160 s64 delta = dccp_delta_seqno(s1, s2);
161
162 WARN_ON(delta < 0);
163 delta -= ndp + 1;
164
165 return delta > 0 ? delta : 0;
166}
167
168/**
169 * dccp_loss_free - Evaluate condition for data loss from RFC 4340, 7.7.1
170 */
171static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
172{
173 return dccp_loss_count(s1, s2, ndp) == 0;
174}
175
176enum {
177 DCCP_MIB_NUM = 0,
178 DCCP_MIB_ACTIVEOPENS, /* ActiveOpens */
179 DCCP_MIB_ESTABRESETS, /* EstabResets */
180 DCCP_MIB_CURRESTAB, /* CurrEstab */
181 DCCP_MIB_OUTSEGS, /* OutSegs */
182 DCCP_MIB_OUTRSTS,
183 DCCP_MIB_ABORTONTIMEOUT,
184 DCCP_MIB_TIMEOUTS,
185 DCCP_MIB_ABORTFAILED,
186 DCCP_MIB_PASSIVEOPENS,
187 DCCP_MIB_ATTEMPTFAILS,
188 DCCP_MIB_OUTDATAGRAMS,
189 DCCP_MIB_INERRS,
190 DCCP_MIB_OPTMANDATORYERROR,
191 DCCP_MIB_INVALIDOPT,
192 __DCCP_MIB_MAX
193};
194
195#define DCCP_MIB_MAX __DCCP_MIB_MAX
196struct dccp_mib {
197 unsigned long mibs[DCCP_MIB_MAX];
198};
199
200DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
201#define DCCP_INC_STATS(field) SNMP_INC_STATS(dccp_statistics, field)
202#define DCCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(dccp_statistics, field)
203#define DCCP_DEC_STATS(field) SNMP_DEC_STATS(dccp_statistics, field)
204
205/*
206 * Checksumming routines
207 */
208static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb)
209{
210 const struct dccp_hdr* dh = dccp_hdr(skb);
211
212 if (dh->dccph_cscov == 0)
213 return skb->len;
214 return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
215}
216
217static inline void dccp_csum_outgoing(struct sk_buff *skb)
218{
219 unsigned int cov = dccp_csum_coverage(skb);
220
221 if (cov >= skb->len)
222 dccp_hdr(skb)->dccph_cscov = 0;
223
224 skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
225}
226
227extern void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb);
228
229extern int dccp_retransmit_skb(struct sock *sk);
230
231extern void dccp_send_ack(struct sock *sk);
232extern void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
233 struct request_sock *rsk);
234
235extern void dccp_send_sync(struct sock *sk, const u64 seq,
236 const enum dccp_pkt_type pkt_type);
237
238/*
239 * TX Packet Dequeueing Interface
240 */
241extern void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb);
242extern bool dccp_qpolicy_full(struct sock *sk);
243extern void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb);
244extern struct sk_buff *dccp_qpolicy_top(struct sock *sk);
245extern struct sk_buff *dccp_qpolicy_pop(struct sock *sk);
246extern bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param);
247
248/*
249 * TX Packet Output and TX Timers
250 */
251extern void dccp_write_xmit(struct sock *sk);
252extern void dccp_write_space(struct sock *sk);
253extern void dccp_flush_write_queue(struct sock *sk, long *time_budget);
254
255extern void dccp_init_xmit_timers(struct sock *sk);
256static inline void dccp_clear_xmit_timers(struct sock *sk)
257{
258 inet_csk_clear_xmit_timers(sk);
259}
260
261extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
262
263extern const char *dccp_packet_name(const int type);
264
265extern void dccp_set_state(struct sock *sk, const int state);
266extern void dccp_done(struct sock *sk);
267
268extern int dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const *dp,
269 struct sk_buff const *skb);
270
271extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
272
273extern struct sock *dccp_create_openreq_child(struct sock *sk,
274 const struct request_sock *req,
275 const struct sk_buff *skb);
276
277extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
278
279extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
280 struct sk_buff *skb,
281 struct request_sock *req,
282 struct dst_entry *dst);
283extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
284 struct request_sock *req,
285 struct request_sock **prev);
286
287extern int dccp_child_process(struct sock *parent, struct sock *child,
288 struct sk_buff *skb);
289extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
290 struct dccp_hdr *dh, unsigned len);
291extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
292 const struct dccp_hdr *dh, const unsigned len);
293
294extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
295extern void dccp_destroy_sock(struct sock *sk);
296
297extern void dccp_close(struct sock *sk, long timeout);
298extern struct sk_buff *dccp_make_response(struct sock *sk,
299 struct dst_entry *dst,
300 struct request_sock *req);
301
302extern int dccp_connect(struct sock *sk);
303extern int dccp_disconnect(struct sock *sk, int flags);
304extern int dccp_getsockopt(struct sock *sk, int level, int optname,
305 char __user *optval, int __user *optlen);
306extern int dccp_setsockopt(struct sock *sk, int level, int optname,
307 char __user *optval, unsigned int optlen);
308#ifdef CONFIG_COMPAT
309extern int compat_dccp_getsockopt(struct sock *sk,
310 int level, int optname,
311 char __user *optval, int __user *optlen);
312extern int compat_dccp_setsockopt(struct sock *sk,
313 int level, int optname,
314 char __user *optval, unsigned int optlen);
315#endif
316extern int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
317extern int dccp_sendmsg(struct kiocb *iocb, struct sock *sk,
318 struct msghdr *msg, size_t size);
319extern int dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
320 struct msghdr *msg, size_t len, int nonblock,
321 int flags, int *addr_len);
322extern void dccp_shutdown(struct sock *sk, int how);
323extern int inet_dccp_listen(struct socket *sock, int backlog);
324extern unsigned int dccp_poll(struct file *file, struct socket *sock,
325 poll_table *wait);
326extern int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
327 int addr_len);
328
329extern struct sk_buff *dccp_ctl_make_reset(struct sock *sk,
330 struct sk_buff *skb);
331extern int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
332extern void dccp_send_close(struct sock *sk, const int active);
333extern int dccp_invalid_packet(struct sk_buff *skb);
334extern u32 dccp_sample_rtt(struct sock *sk, long delta);
335
336static inline int dccp_bad_service_code(const struct sock *sk,
337 const __be32 service)
338{
339 const struct dccp_sock *dp = dccp_sk(sk);
340
341 if (dp->dccps_service == service)
342 return 0;
343 return !dccp_list_has_service(dp->dccps_service_list, service);
344}
345
346/**
347 * dccp_skb_cb - DCCP per-packet control information
348 * @dccpd_type: one of %dccp_pkt_type (or unknown)
349 * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1
350 * @dccpd_reset_code: one of %dccp_reset_codes
351 * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code)
352 * @dccpd_opt_len: total length of all options (5.8) in the packet
353 * @dccpd_seq: sequence number
354 * @dccpd_ack_seq: acknowledgment number subheader field value
355 * This is used for transmission as well as for reception.
356 */
357struct dccp_skb_cb {
358 union {
359 struct inet_skb_parm h4;
360#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
361 struct inet6_skb_parm h6;
362#endif
363 } header;
364 __u8 dccpd_type:4;
365 __u8 dccpd_ccval:4;
366 __u8 dccpd_reset_code,
367 dccpd_reset_data[3];
368 __u16 dccpd_opt_len;
369 __u64 dccpd_seq;
370 __u64 dccpd_ack_seq;
371};
372
373#define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
374
375/* RFC 4340, sec. 7.7 */
376static inline int dccp_non_data_packet(const struct sk_buff *skb)
377{
378 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
379
380 return type == DCCP_PKT_ACK ||
381 type == DCCP_PKT_CLOSE ||
382 type == DCCP_PKT_CLOSEREQ ||
383 type == DCCP_PKT_RESET ||
384 type == DCCP_PKT_SYNC ||
385 type == DCCP_PKT_SYNCACK;
386}
387
388/* RFC 4340, sec. 7.7 */
389static inline int dccp_data_packet(const struct sk_buff *skb)
390{
391 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
392
393 return type == DCCP_PKT_DATA ||
394 type == DCCP_PKT_DATAACK ||
395 type == DCCP_PKT_REQUEST ||
396 type == DCCP_PKT_RESPONSE;
397}
398
399static inline int dccp_packet_without_ack(const struct sk_buff *skb)
400{
401 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
402
403 return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
404}
405
406#define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
407
408static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
409{
410 struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
411 sizeof(*dh));
412 dh->dccph_seq2 = 0;
413 dh->dccph_seq = htons((gss >> 32) & 0xfffff);
414 dhx->dccph_seq_low = htonl(gss & 0xffffffff);
415}
416
417static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
418 const u64 gsr)
419{
420 dhack->dccph_reserved1 = 0;
421 dhack->dccph_ack_nr_high = htons(gsr >> 32);
422 dhack->dccph_ack_nr_low = htonl(gsr & 0xffffffff);
423}
424
425static inline void dccp_update_gsr(struct sock *sk, u64 seq)
426{
427 struct dccp_sock *dp = dccp_sk(sk);
428
429 if (after48(seq, dp->dccps_gsr))
430 dp->dccps_gsr = seq;
431 /* Sequence validity window depends on remote Sequence Window (7.5.1) */
432 dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4);
433 /*
434 * Adjust SWL so that it is not below ISR. In contrast to RFC 4340,
435 * 7.5.1 we perform this check beyond the initial handshake: W/W' are
436 * always > 32, so for the first W/W' packets in the lifetime of a
437 * connection we always have to adjust SWL.
438 * A second reason why we are doing this is that the window depends on
439 * the feature-remote value of Sequence Window: nothing stops the peer
440 * from updating this value while we are busy adjusting SWL for the
441 * first W packets (we would have to count from scratch again then).
442 * Therefore it is safer to always make sure that the Sequence Window
443 * is not artificially extended by a peer who grows SWL downwards by
444 * continually updating the feature-remote Sequence-Window.
445 * If sequence numbers wrap it is bad luck. But that will take a while
446 * (48 bit), and this measure prevents Sequence-number attacks.
447 */
448 if (before48(dp->dccps_swl, dp->dccps_isr))
449 dp->dccps_swl = dp->dccps_isr;
450 dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4);
451}
452
453static inline void dccp_update_gss(struct sock *sk, u64 seq)
454{
455 struct dccp_sock *dp = dccp_sk(sk);
456
457 dp->dccps_gss = seq;
458 /* Ack validity window depends on local Sequence Window value (7.5.1) */
459 dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win);
460 /* Adjust AWL so that it is not below ISS - see comment above for SWL */
461 if (before48(dp->dccps_awl, dp->dccps_iss))
462 dp->dccps_awl = dp->dccps_iss;
463 dp->dccps_awh = dp->dccps_gss;
464}
465
466static inline int dccp_ackvec_pending(const struct sock *sk)
467{
468 return dccp_sk(sk)->dccps_hc_rx_ackvec != NULL &&
469 !dccp_ackvec_is_empty(dccp_sk(sk)->dccps_hc_rx_ackvec);
470}
471
472static inline int dccp_ack_pending(const struct sock *sk)
473{
474 return dccp_ackvec_pending(sk) || inet_csk_ack_scheduled(sk);
475}
476
477extern int dccp_feat_finalise_settings(struct dccp_sock *dp);
478extern int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq);
479extern int dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*,
480 struct sk_buff *skb);
481extern int dccp_feat_activate_values(struct sock *sk, struct list_head *fn);
482extern void dccp_feat_list_purge(struct list_head *fn_list);
483
484extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
485extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);
486extern int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed);
487extern u32 dccp_timestamp(void);
488extern void dccp_timestamping_init(void);
489extern int dccp_insert_option(struct sk_buff *skb, unsigned char option,
490 const void *value, unsigned char len);
491
492#ifdef CONFIG_SYSCTL
493extern int dccp_sysctl_init(void);
494extern void dccp_sysctl_exit(void);
495#else
496static inline int dccp_sysctl_init(void)
497{
498 return 0;
499}
500
501static inline void dccp_sysctl_exit(void)
502{
503}
504#endif
505
506#endif /* _DCCP_H */
1/* SPDX-License-Identifier: GPL-2.0-only */
2#ifndef _DCCP_H
3#define _DCCP_H
4/*
5 * net/dccp/dccp.h
6 *
7 * An implementation of the DCCP protocol
8 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
9 * Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
10 */
11
12#include <linux/dccp.h>
13#include <linux/ktime.h>
14#include <net/snmp.h>
15#include <net/sock.h>
16#include <net/tcp.h>
17#include "ackvec.h"
18
19/*
20 * DCCP - specific warning and debugging macros.
21 */
22#define DCCP_WARN(fmt, ...) \
23 net_warn_ratelimited("%s: " fmt, __func__, ##__VA_ARGS__)
24#define DCCP_CRIT(fmt, a...) printk(KERN_CRIT fmt " at %s:%d/%s()\n", ##a, \
25 __FILE__, __LINE__, __func__)
26#define DCCP_BUG(a...) do { DCCP_CRIT("BUG: " a); dump_stack(); } while(0)
27#define DCCP_BUG_ON(cond) do { if (unlikely((cond) != 0)) \
28 DCCP_BUG("\"%s\" holds (exception!)", \
29 __stringify(cond)); \
30 } while (0)
31
32#define DCCP_PRINTK(enable, fmt, args...) do { if (enable) \
33 printk(fmt, ##args); \
34 } while(0)
35#define DCCP_PR_DEBUG(enable, fmt, a...) DCCP_PRINTK(enable, KERN_DEBUG \
36 "%s: " fmt, __func__, ##a)
37
38#ifdef CONFIG_IP_DCCP_DEBUG
39extern bool dccp_debug;
40#define dccp_pr_debug(format, a...) DCCP_PR_DEBUG(dccp_debug, format, ##a)
41#define dccp_pr_debug_cat(format, a...) DCCP_PRINTK(dccp_debug, format, ##a)
42#define dccp_debug(fmt, a...) dccp_pr_debug_cat(KERN_DEBUG fmt, ##a)
43#else
44#define dccp_pr_debug(format, a...) do {} while (0)
45#define dccp_pr_debug_cat(format, a...) do {} while (0)
46#define dccp_debug(format, a...) do {} while (0)
47#endif
48
49extern struct inet_hashinfo dccp_hashinfo;
50
51DECLARE_PER_CPU(unsigned int, dccp_orphan_count);
52
53void dccp_time_wait(struct sock *sk, int state, int timeo);
54
55/*
56 * Set safe upper bounds for header and option length. Since Data Offset is 8
57 * bits (RFC 4340, sec. 5.1), the total header length can never be more than
58 * 4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1):
59 * - DCCP-Response with ACK Subheader and 4 bytes of Service code OR
60 * - DCCP-Reset with ACK Subheader and 4 bytes of Reset Code fields
61 * Hence a safe upper bound for the maximum option length is 1020-28 = 992
62 */
63#define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(uint32_t))
64#define DCCP_MAX_PACKET_HDR 28
65#define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR)
66#define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER)
67
68/* Upper bound for initial feature-negotiation overhead (padded to 32 bits) */
69#define DCCP_FEATNEG_OVERHEAD (32 * sizeof(uint32_t))
70
71#define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
72 * state, about 60 seconds */
73
74/* RFC 1122, 4.2.3.1 initial RTO value */
75#define DCCP_TIMEOUT_INIT ((unsigned int)(3 * HZ))
76
77/*
78 * The maximum back-off value for retransmissions. This is needed for
79 * - retransmitting client-Requests (sec. 8.1.1),
80 * - retransmitting Close/CloseReq when closing (sec. 8.3),
81 * - feature-negotiation retransmission (sec. 6.6.3),
82 * - Acks in client-PARTOPEN state (sec. 8.1.5).
83 */
84#define DCCP_RTO_MAX ((unsigned int)(64 * HZ))
85
86/*
87 * RTT sampling: sanity bounds and fallback RTT value from RFC 4340, section 3.4
88 */
89#define DCCP_SANE_RTT_MIN 100
90#define DCCP_FALLBACK_RTT (USEC_PER_SEC / 5)
91#define DCCP_SANE_RTT_MAX (3 * USEC_PER_SEC)
92
93/* sysctl variables for DCCP */
94extern int sysctl_dccp_request_retries;
95extern int sysctl_dccp_retries1;
96extern int sysctl_dccp_retries2;
97extern int sysctl_dccp_tx_qlen;
98extern int sysctl_dccp_sync_ratelimit;
99
100/*
101 * 48-bit sequence number arithmetic (signed and unsigned)
102 */
103#define INT48_MIN 0x800000000000LL /* 2^47 */
104#define UINT48_MAX 0xFFFFFFFFFFFFLL /* 2^48 - 1 */
105#define COMPLEMENT48(x) (0x1000000000000LL - (x)) /* 2^48 - x */
106#define TO_SIGNED48(x) (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x)))
107#define TO_UNSIGNED48(x) (((x) >= 0)? (x) : COMPLEMENT48(-(x)))
108#define ADD48(a, b) (((a) + (b)) & UINT48_MAX)
109#define SUB48(a, b) ADD48((a), COMPLEMENT48(b))
110
111static inline void dccp_inc_seqno(u64 *seqno)
112{
113 *seqno = ADD48(*seqno, 1);
114}
115
116/* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
117static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
118{
119 u64 delta = SUB48(seqno2, seqno1);
120
121 return TO_SIGNED48(delta);
122}
123
124/* is seq1 < seq2 ? */
125static inline int before48(const u64 seq1, const u64 seq2)
126{
127 return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
128}
129
130/* is seq1 > seq2 ? */
131#define after48(seq1, seq2) before48(seq2, seq1)
132
133/* is seq2 <= seq1 <= seq3 ? */
134static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
135{
136 return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
137}
138
139/**
140 * dccp_loss_count - Approximate the number of lost data packets in a burst loss
141 * @s1: last known sequence number before the loss ('hole')
142 * @s2: first sequence number seen after the 'hole'
143 * @ndp: NDP count on packet with sequence number @s2
144 */
145static inline u64 dccp_loss_count(const u64 s1, const u64 s2, const u64 ndp)
146{
147 s64 delta = dccp_delta_seqno(s1, s2);
148
149 WARN_ON(delta < 0);
150 delta -= ndp + 1;
151
152 return delta > 0 ? delta : 0;
153}
154
155/**
156 * dccp_loss_free - Evaluate condition for data loss from RFC 4340, 7.7.1
157 */
158static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
159{
160 return dccp_loss_count(s1, s2, ndp) == 0;
161}
162
163enum {
164 DCCP_MIB_NUM = 0,
165 DCCP_MIB_ACTIVEOPENS, /* ActiveOpens */
166 DCCP_MIB_ESTABRESETS, /* EstabResets */
167 DCCP_MIB_CURRESTAB, /* CurrEstab */
168 DCCP_MIB_OUTSEGS, /* OutSegs */
169 DCCP_MIB_OUTRSTS,
170 DCCP_MIB_ABORTONTIMEOUT,
171 DCCP_MIB_TIMEOUTS,
172 DCCP_MIB_ABORTFAILED,
173 DCCP_MIB_PASSIVEOPENS,
174 DCCP_MIB_ATTEMPTFAILS,
175 DCCP_MIB_OUTDATAGRAMS,
176 DCCP_MIB_INERRS,
177 DCCP_MIB_OPTMANDATORYERROR,
178 DCCP_MIB_INVALIDOPT,
179 __DCCP_MIB_MAX
180};
181
182#define DCCP_MIB_MAX __DCCP_MIB_MAX
183struct dccp_mib {
184 unsigned long mibs[DCCP_MIB_MAX];
185};
186
187DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
188#define DCCP_INC_STATS(field) SNMP_INC_STATS(dccp_statistics, field)
189#define __DCCP_INC_STATS(field) __SNMP_INC_STATS(dccp_statistics, field)
190#define DCCP_DEC_STATS(field) SNMP_DEC_STATS(dccp_statistics, field)
191
192/*
193 * Checksumming routines
194 */
195static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb)
196{
197 const struct dccp_hdr* dh = dccp_hdr(skb);
198
199 if (dh->dccph_cscov == 0)
200 return skb->len;
201 return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
202}
203
204static inline void dccp_csum_outgoing(struct sk_buff *skb)
205{
206 unsigned int cov = dccp_csum_coverage(skb);
207
208 if (cov >= skb->len)
209 dccp_hdr(skb)->dccph_cscov = 0;
210
211 skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
212}
213
214void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb);
215
216int dccp_retransmit_skb(struct sock *sk);
217
218void dccp_send_ack(struct sock *sk);
219void dccp_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
220 struct request_sock *rsk);
221
222void dccp_send_sync(struct sock *sk, const u64 seq,
223 const enum dccp_pkt_type pkt_type);
224
225/*
226 * TX Packet Dequeueing Interface
227 */
228void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb);
229bool dccp_qpolicy_full(struct sock *sk);
230void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb);
231struct sk_buff *dccp_qpolicy_top(struct sock *sk);
232struct sk_buff *dccp_qpolicy_pop(struct sock *sk);
233bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param);
234
235/*
236 * TX Packet Output and TX Timers
237 */
238void dccp_write_xmit(struct sock *sk);
239void dccp_write_space(struct sock *sk);
240void dccp_flush_write_queue(struct sock *sk, long *time_budget);
241
242void dccp_init_xmit_timers(struct sock *sk);
243static inline void dccp_clear_xmit_timers(struct sock *sk)
244{
245 inet_csk_clear_xmit_timers(sk);
246}
247
248unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
249
250const char *dccp_packet_name(const int type);
251
252void dccp_set_state(struct sock *sk, const int state);
253void dccp_done(struct sock *sk);
254
255int dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const *dp,
256 struct sk_buff const *skb);
257
258int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
259
260struct sock *dccp_create_openreq_child(const struct sock *sk,
261 const struct request_sock *req,
262 const struct sk_buff *skb);
263
264int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
265
266struct sock *dccp_v4_request_recv_sock(const struct sock *sk, struct sk_buff *skb,
267 struct request_sock *req,
268 struct dst_entry *dst,
269 struct request_sock *req_unhash,
270 bool *own_req);
271struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
272 struct request_sock *req);
273
274int dccp_child_process(struct sock *parent, struct sock *child,
275 struct sk_buff *skb);
276int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
277 struct dccp_hdr *dh, unsigned int len);
278int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
279 const struct dccp_hdr *dh, const unsigned int len);
280
281void dccp_destruct_common(struct sock *sk);
282int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
283void dccp_destroy_sock(struct sock *sk);
284
285void dccp_close(struct sock *sk, long timeout);
286struct sk_buff *dccp_make_response(const struct sock *sk, struct dst_entry *dst,
287 struct request_sock *req);
288
289int dccp_connect(struct sock *sk);
290int dccp_disconnect(struct sock *sk, int flags);
291int dccp_getsockopt(struct sock *sk, int level, int optname,
292 char __user *optval, int __user *optlen);
293int dccp_setsockopt(struct sock *sk, int level, int optname,
294 sockptr_t optval, unsigned int optlen);
295int dccp_ioctl(struct sock *sk, int cmd, int *karg);
296int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
297int dccp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags,
298 int *addr_len);
299void dccp_shutdown(struct sock *sk, int how);
300int inet_dccp_listen(struct socket *sock, int backlog);
301__poll_t dccp_poll(struct file *file, struct socket *sock,
302 poll_table *wait);
303int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
304void dccp_req_err(struct sock *sk, u64 seq);
305
306struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *skb);
307int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
308void dccp_send_close(struct sock *sk, const int active);
309int dccp_invalid_packet(struct sk_buff *skb);
310u32 dccp_sample_rtt(struct sock *sk, long delta);
311
312static inline bool dccp_bad_service_code(const struct sock *sk,
313 const __be32 service)
314{
315 const struct dccp_sock *dp = dccp_sk(sk);
316
317 if (dp->dccps_service == service)
318 return false;
319 return !dccp_list_has_service(dp->dccps_service_list, service);
320}
321
322/**
323 * dccp_skb_cb - DCCP per-packet control information
324 * @dccpd_type: one of %dccp_pkt_type (or unknown)
325 * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1
326 * @dccpd_reset_code: one of %dccp_reset_codes
327 * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code)
328 * @dccpd_opt_len: total length of all options (5.8) in the packet
329 * @dccpd_seq: sequence number
330 * @dccpd_ack_seq: acknowledgment number subheader field value
331 *
332 * This is used for transmission as well as for reception.
333 */
334struct dccp_skb_cb {
335 union {
336 struct inet_skb_parm h4;
337#if IS_ENABLED(CONFIG_IPV6)
338 struct inet6_skb_parm h6;
339#endif
340 } header;
341 __u8 dccpd_type:4;
342 __u8 dccpd_ccval:4;
343 __u8 dccpd_reset_code,
344 dccpd_reset_data[3];
345 __u16 dccpd_opt_len;
346 __u64 dccpd_seq;
347 __u64 dccpd_ack_seq;
348};
349
350#define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
351
352/* RFC 4340, sec. 7.7 */
353static inline int dccp_non_data_packet(const struct sk_buff *skb)
354{
355 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
356
357 return type == DCCP_PKT_ACK ||
358 type == DCCP_PKT_CLOSE ||
359 type == DCCP_PKT_CLOSEREQ ||
360 type == DCCP_PKT_RESET ||
361 type == DCCP_PKT_SYNC ||
362 type == DCCP_PKT_SYNCACK;
363}
364
365/* RFC 4340, sec. 7.7 */
366static inline int dccp_data_packet(const struct sk_buff *skb)
367{
368 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
369
370 return type == DCCP_PKT_DATA ||
371 type == DCCP_PKT_DATAACK ||
372 type == DCCP_PKT_REQUEST ||
373 type == DCCP_PKT_RESPONSE;
374}
375
376static inline int dccp_packet_without_ack(const struct sk_buff *skb)
377{
378 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
379
380 return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
381}
382
383#define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
384
385static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
386{
387 struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
388 sizeof(*dh));
389 dh->dccph_seq2 = 0;
390 dh->dccph_seq = htons((gss >> 32) & 0xfffff);
391 dhx->dccph_seq_low = htonl(gss & 0xffffffff);
392}
393
394static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
395 const u64 gsr)
396{
397 dhack->dccph_reserved1 = 0;
398 dhack->dccph_ack_nr_high = htons(gsr >> 32);
399 dhack->dccph_ack_nr_low = htonl(gsr & 0xffffffff);
400}
401
402static inline void dccp_update_gsr(struct sock *sk, u64 seq)
403{
404 struct dccp_sock *dp = dccp_sk(sk);
405
406 if (after48(seq, dp->dccps_gsr))
407 dp->dccps_gsr = seq;
408 /* Sequence validity window depends on remote Sequence Window (7.5.1) */
409 dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4);
410 /*
411 * Adjust SWL so that it is not below ISR. In contrast to RFC 4340,
412 * 7.5.1 we perform this check beyond the initial handshake: W/W' are
413 * always > 32, so for the first W/W' packets in the lifetime of a
414 * connection we always have to adjust SWL.
415 * A second reason why we are doing this is that the window depends on
416 * the feature-remote value of Sequence Window: nothing stops the peer
417 * from updating this value while we are busy adjusting SWL for the
418 * first W packets (we would have to count from scratch again then).
419 * Therefore it is safer to always make sure that the Sequence Window
420 * is not artificially extended by a peer who grows SWL downwards by
421 * continually updating the feature-remote Sequence-Window.
422 * If sequence numbers wrap it is bad luck. But that will take a while
423 * (48 bit), and this measure prevents Sequence-number attacks.
424 */
425 if (before48(dp->dccps_swl, dp->dccps_isr))
426 dp->dccps_swl = dp->dccps_isr;
427 dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4);
428}
429
430static inline void dccp_update_gss(struct sock *sk, u64 seq)
431{
432 struct dccp_sock *dp = dccp_sk(sk);
433
434 dp->dccps_gss = seq;
435 /* Ack validity window depends on local Sequence Window value (7.5.1) */
436 dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win);
437 /* Adjust AWL so that it is not below ISS - see comment above for SWL */
438 if (before48(dp->dccps_awl, dp->dccps_iss))
439 dp->dccps_awl = dp->dccps_iss;
440 dp->dccps_awh = dp->dccps_gss;
441}
442
443static inline int dccp_ackvec_pending(const struct sock *sk)
444{
445 return dccp_sk(sk)->dccps_hc_rx_ackvec != NULL &&
446 !dccp_ackvec_is_empty(dccp_sk(sk)->dccps_hc_rx_ackvec);
447}
448
449static inline int dccp_ack_pending(const struct sock *sk)
450{
451 return dccp_ackvec_pending(sk) || inet_csk_ack_scheduled(sk);
452}
453
454int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val);
455int dccp_feat_finalise_settings(struct dccp_sock *dp);
456int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq);
457int dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*,
458 struct sk_buff *skb);
459int dccp_feat_activate_values(struct sock *sk, struct list_head *fn);
460void dccp_feat_list_purge(struct list_head *fn_list);
461
462int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
463int dccp_insert_options_rsk(struct dccp_request_sock *, struct sk_buff *);
464u32 dccp_timestamp(void);
465void dccp_timestamping_init(void);
466int dccp_insert_option(struct sk_buff *skb, unsigned char option,
467 const void *value, unsigned char len);
468
469#ifdef CONFIG_SYSCTL
470int dccp_sysctl_init(void);
471void dccp_sysctl_exit(void);
472#else
473static inline int dccp_sysctl_init(void)
474{
475 return 0;
476}
477
478static inline void dccp_sysctl_exit(void)
479{
480}
481#endif
482
483#endif /* _DCCP_H */