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
39 extern 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...)
45 #define dccp_pr_debug_cat(format, a...)
46 #define dccp_debug(format, a...)
47 #endif
48
49 extern struct inet_hashinfo dccp_hashinfo;
50
51 extern struct percpu_counter dccp_orphan_count;
52
53 void 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 */
94 extern int sysctl_dccp_request_retries;
95 extern int sysctl_dccp_retries1;
96 extern int sysctl_dccp_retries2;
97 extern int sysctl_dccp_tx_qlen;
98 extern 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
dccp_set_seqno(u64 * seqno,u64 value)111 static inline void dccp_set_seqno(u64 *seqno, u64 value)
112 {
113 *seqno = value & UINT48_MAX;
114 }
115
dccp_inc_seqno(u64 * seqno)116 static inline void dccp_inc_seqno(u64 *seqno)
117 {
118 *seqno = ADD48(*seqno, 1);
119 }
120
121 /* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
dccp_delta_seqno(const u64 seqno1,const u64 seqno2)122 static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
123 {
124 u64 delta = SUB48(seqno2, seqno1);
125
126 return TO_SIGNED48(delta);
127 }
128
129 /* is seq1 < seq2 ? */
before48(const u64 seq1,const u64 seq2)130 static inline int before48(const u64 seq1, const u64 seq2)
131 {
132 return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
133 }
134
135 /* is seq1 > seq2 ? */
136 #define after48(seq1, seq2) before48(seq2, seq1)
137
138 /* is seq2 <= seq1 <= seq3 ? */
between48(const u64 seq1,const u64 seq2,const u64 seq3)139 static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
140 {
141 return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
142 }
143
max48(const u64 seq1,const u64 seq2)144 static inline u64 max48(const u64 seq1, const u64 seq2)
145 {
146 return after48(seq1, seq2) ? seq1 : seq2;
147 }
148
149 /**
150 * dccp_loss_count - Approximate the number of lost data packets in a burst loss
151 * @s1: last known sequence number before the loss ('hole')
152 * @s2: first sequence number seen after the 'hole'
153 * @ndp: NDP count on packet with sequence number @s2
154 */
dccp_loss_count(const u64 s1,const u64 s2,const u64 ndp)155 static inline u64 dccp_loss_count(const u64 s1, const u64 s2, const u64 ndp)
156 {
157 s64 delta = dccp_delta_seqno(s1, s2);
158
159 WARN_ON(delta < 0);
160 delta -= ndp + 1;
161
162 return delta > 0 ? delta : 0;
163 }
164
165 /**
166 * dccp_loss_free - Evaluate condition for data loss from RFC 4340, 7.7.1
167 */
dccp_loss_free(const u64 s1,const u64 s2,const u64 ndp)168 static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
169 {
170 return dccp_loss_count(s1, s2, ndp) == 0;
171 }
172
173 enum {
174 DCCP_MIB_NUM = 0,
175 DCCP_MIB_ACTIVEOPENS, /* ActiveOpens */
176 DCCP_MIB_ESTABRESETS, /* EstabResets */
177 DCCP_MIB_CURRESTAB, /* CurrEstab */
178 DCCP_MIB_OUTSEGS, /* OutSegs */
179 DCCP_MIB_OUTRSTS,
180 DCCP_MIB_ABORTONTIMEOUT,
181 DCCP_MIB_TIMEOUTS,
182 DCCP_MIB_ABORTFAILED,
183 DCCP_MIB_PASSIVEOPENS,
184 DCCP_MIB_ATTEMPTFAILS,
185 DCCP_MIB_OUTDATAGRAMS,
186 DCCP_MIB_INERRS,
187 DCCP_MIB_OPTMANDATORYERROR,
188 DCCP_MIB_INVALIDOPT,
189 __DCCP_MIB_MAX
190 };
191
192 #define DCCP_MIB_MAX __DCCP_MIB_MAX
193 struct dccp_mib {
194 unsigned long mibs[DCCP_MIB_MAX];
195 };
196
197 DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
198 #define DCCP_INC_STATS(field) SNMP_INC_STATS(dccp_statistics, field)
199 #define __DCCP_INC_STATS(field) __SNMP_INC_STATS(dccp_statistics, field)
200 #define DCCP_DEC_STATS(field) SNMP_DEC_STATS(dccp_statistics, field)
201
202 /*
203 * Checksumming routines
204 */
dccp_csum_coverage(const struct sk_buff * skb)205 static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb)
206 {
207 const struct dccp_hdr* dh = dccp_hdr(skb);
208
209 if (dh->dccph_cscov == 0)
210 return skb->len;
211 return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
212 }
213
dccp_csum_outgoing(struct sk_buff * skb)214 static inline void dccp_csum_outgoing(struct sk_buff *skb)
215 {
216 unsigned int cov = dccp_csum_coverage(skb);
217
218 if (cov >= skb->len)
219 dccp_hdr(skb)->dccph_cscov = 0;
220
221 skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
222 }
223
224 void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb);
225
226 int dccp_retransmit_skb(struct sock *sk);
227
228 void dccp_send_ack(struct sock *sk);
229 void dccp_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
230 struct request_sock *rsk);
231
232 void dccp_send_sync(struct sock *sk, const u64 seq,
233 const enum dccp_pkt_type pkt_type);
234
235 /*
236 * TX Packet Dequeueing Interface
237 */
238 void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb);
239 bool dccp_qpolicy_full(struct sock *sk);
240 void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb);
241 struct sk_buff *dccp_qpolicy_top(struct sock *sk);
242 struct sk_buff *dccp_qpolicy_pop(struct sock *sk);
243 bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param);
244
245 /*
246 * TX Packet Output and TX Timers
247 */
248 void dccp_write_xmit(struct sock *sk);
249 void dccp_write_space(struct sock *sk);
250 void dccp_flush_write_queue(struct sock *sk, long *time_budget);
251
252 void dccp_init_xmit_timers(struct sock *sk);
dccp_clear_xmit_timers(struct sock * sk)253 static inline void dccp_clear_xmit_timers(struct sock *sk)
254 {
255 inet_csk_clear_xmit_timers(sk);
256 }
257
258 unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
259
260 const char *dccp_packet_name(const int type);
261
262 void dccp_set_state(struct sock *sk, const int state);
263 void dccp_done(struct sock *sk);
264
265 int dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const *dp,
266 struct sk_buff const *skb);
267
268 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
269
270 struct sock *dccp_create_openreq_child(const struct sock *sk,
271 const struct request_sock *req,
272 const struct sk_buff *skb);
273
274 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
275
276 struct sock *dccp_v4_request_recv_sock(const struct sock *sk, struct sk_buff *skb,
277 struct request_sock *req,
278 struct dst_entry *dst,
279 struct request_sock *req_unhash,
280 bool *own_req);
281 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
282 struct request_sock *req);
283
284 int dccp_child_process(struct sock *parent, struct sock *child,
285 struct sk_buff *skb);
286 int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
287 struct dccp_hdr *dh, unsigned int len);
288 int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
289 const struct dccp_hdr *dh, const unsigned int len);
290
291 int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
292 void dccp_destroy_sock(struct sock *sk);
293
294 void dccp_close(struct sock *sk, long timeout);
295 struct sk_buff *dccp_make_response(const struct sock *sk, struct dst_entry *dst,
296 struct request_sock *req);
297
298 int dccp_connect(struct sock *sk);
299 int dccp_disconnect(struct sock *sk, int flags);
300 int dccp_getsockopt(struct sock *sk, int level, int optname,
301 char __user *optval, int __user *optlen);
302 int dccp_setsockopt(struct sock *sk, int level, int optname,
303 char __user *optval, unsigned int optlen);
304 #ifdef CONFIG_COMPAT
305 int compat_dccp_getsockopt(struct sock *sk, int level, int optname,
306 char __user *optval, int __user *optlen);
307 int compat_dccp_setsockopt(struct sock *sk, int level, int optname,
308 char __user *optval, unsigned int optlen);
309 #endif
310 int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
311 int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
312 int dccp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
313 int flags, int *addr_len);
314 void dccp_shutdown(struct sock *sk, int how);
315 int inet_dccp_listen(struct socket *sock, int backlog);
316 __poll_t dccp_poll(struct file *file, struct socket *sock,
317 poll_table *wait);
318 int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
319 void dccp_req_err(struct sock *sk, u64 seq);
320
321 struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *skb);
322 int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
323 void dccp_send_close(struct sock *sk, const int active);
324 int dccp_invalid_packet(struct sk_buff *skb);
325 u32 dccp_sample_rtt(struct sock *sk, long delta);
326
dccp_bad_service_code(const struct sock * sk,const __be32 service)327 static inline bool dccp_bad_service_code(const struct sock *sk,
328 const __be32 service)
329 {
330 const struct dccp_sock *dp = dccp_sk(sk);
331
332 if (dp->dccps_service == service)
333 return false;
334 return !dccp_list_has_service(dp->dccps_service_list, service);
335 }
336
337 /**
338 * dccp_skb_cb - DCCP per-packet control information
339 * @dccpd_type: one of %dccp_pkt_type (or unknown)
340 * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1
341 * @dccpd_reset_code: one of %dccp_reset_codes
342 * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code)
343 * @dccpd_opt_len: total length of all options (5.8) in the packet
344 * @dccpd_seq: sequence number
345 * @dccpd_ack_seq: acknowledgment number subheader field value
346 *
347 * This is used for transmission as well as for reception.
348 */
349 struct dccp_skb_cb {
350 union {
351 struct inet_skb_parm h4;
352 #if IS_ENABLED(CONFIG_IPV6)
353 struct inet6_skb_parm h6;
354 #endif
355 } header;
356 __u8 dccpd_type:4;
357 __u8 dccpd_ccval:4;
358 __u8 dccpd_reset_code,
359 dccpd_reset_data[3];
360 __u16 dccpd_opt_len;
361 __u64 dccpd_seq;
362 __u64 dccpd_ack_seq;
363 };
364
365 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
366
367 /* RFC 4340, sec. 7.7 */
dccp_non_data_packet(const struct sk_buff * skb)368 static inline int dccp_non_data_packet(const struct sk_buff *skb)
369 {
370 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
371
372 return type == DCCP_PKT_ACK ||
373 type == DCCP_PKT_CLOSE ||
374 type == DCCP_PKT_CLOSEREQ ||
375 type == DCCP_PKT_RESET ||
376 type == DCCP_PKT_SYNC ||
377 type == DCCP_PKT_SYNCACK;
378 }
379
380 /* RFC 4340, sec. 7.7 */
dccp_data_packet(const struct sk_buff * skb)381 static inline int dccp_data_packet(const struct sk_buff *skb)
382 {
383 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
384
385 return type == DCCP_PKT_DATA ||
386 type == DCCP_PKT_DATAACK ||
387 type == DCCP_PKT_REQUEST ||
388 type == DCCP_PKT_RESPONSE;
389 }
390
dccp_packet_without_ack(const struct sk_buff * skb)391 static inline int dccp_packet_without_ack(const struct sk_buff *skb)
392 {
393 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
394
395 return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
396 }
397
398 #define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
399
dccp_hdr_set_seq(struct dccp_hdr * dh,const u64 gss)400 static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
401 {
402 struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
403 sizeof(*dh));
404 dh->dccph_seq2 = 0;
405 dh->dccph_seq = htons((gss >> 32) & 0xfffff);
406 dhx->dccph_seq_low = htonl(gss & 0xffffffff);
407 }
408
dccp_hdr_set_ack(struct dccp_hdr_ack_bits * dhack,const u64 gsr)409 static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
410 const u64 gsr)
411 {
412 dhack->dccph_reserved1 = 0;
413 dhack->dccph_ack_nr_high = htons(gsr >> 32);
414 dhack->dccph_ack_nr_low = htonl(gsr & 0xffffffff);
415 }
416
dccp_update_gsr(struct sock * sk,u64 seq)417 static inline void dccp_update_gsr(struct sock *sk, u64 seq)
418 {
419 struct dccp_sock *dp = dccp_sk(sk);
420
421 if (after48(seq, dp->dccps_gsr))
422 dp->dccps_gsr = seq;
423 /* Sequence validity window depends on remote Sequence Window (7.5.1) */
424 dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4);
425 /*
426 * Adjust SWL so that it is not below ISR. In contrast to RFC 4340,
427 * 7.5.1 we perform this check beyond the initial handshake: W/W' are
428 * always > 32, so for the first W/W' packets in the lifetime of a
429 * connection we always have to adjust SWL.
430 * A second reason why we are doing this is that the window depends on
431 * the feature-remote value of Sequence Window: nothing stops the peer
432 * from updating this value while we are busy adjusting SWL for the
433 * first W packets (we would have to count from scratch again then).
434 * Therefore it is safer to always make sure that the Sequence Window
435 * is not artificially extended by a peer who grows SWL downwards by
436 * continually updating the feature-remote Sequence-Window.
437 * If sequence numbers wrap it is bad luck. But that will take a while
438 * (48 bit), and this measure prevents Sequence-number attacks.
439 */
440 if (before48(dp->dccps_swl, dp->dccps_isr))
441 dp->dccps_swl = dp->dccps_isr;
442 dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4);
443 }
444
dccp_update_gss(struct sock * sk,u64 seq)445 static inline void dccp_update_gss(struct sock *sk, u64 seq)
446 {
447 struct dccp_sock *dp = dccp_sk(sk);
448
449 dp->dccps_gss = seq;
450 /* Ack validity window depends on local Sequence Window value (7.5.1) */
451 dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win);
452 /* Adjust AWL so that it is not below ISS - see comment above for SWL */
453 if (before48(dp->dccps_awl, dp->dccps_iss))
454 dp->dccps_awl = dp->dccps_iss;
455 dp->dccps_awh = dp->dccps_gss;
456 }
457
dccp_ackvec_pending(const struct sock * sk)458 static inline int dccp_ackvec_pending(const struct sock *sk)
459 {
460 return dccp_sk(sk)->dccps_hc_rx_ackvec != NULL &&
461 !dccp_ackvec_is_empty(dccp_sk(sk)->dccps_hc_rx_ackvec);
462 }
463
dccp_ack_pending(const struct sock * sk)464 static inline int dccp_ack_pending(const struct sock *sk)
465 {
466 return dccp_ackvec_pending(sk) || inet_csk_ack_scheduled(sk);
467 }
468
469 int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val);
470 int dccp_feat_finalise_settings(struct dccp_sock *dp);
471 int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq);
472 int dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*,
473 struct sk_buff *skb);
474 int dccp_feat_activate_values(struct sock *sk, struct list_head *fn);
475 void dccp_feat_list_purge(struct list_head *fn_list);
476
477 int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
478 int dccp_insert_options_rsk(struct dccp_request_sock *, struct sk_buff *);
479 u32 dccp_timestamp(void);
480 void dccp_timestamping_init(void);
481 int dccp_insert_option(struct sk_buff *skb, unsigned char option,
482 const void *value, unsigned char len);
483
484 #ifdef CONFIG_SYSCTL
485 int dccp_sysctl_init(void);
486 void dccp_sysctl_exit(void);
487 #else
dccp_sysctl_init(void)488 static inline int dccp_sysctl_init(void)
489 {
490 return 0;
491 }
492
dccp_sysctl_exit(void)493 static inline void dccp_sysctl_exit(void)
494 {
495 }
496 #endif
497
498 #endif /* _DCCP_H */
499