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__, __FUNCTION__)
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, __FUNCTION__, ##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)
46 #define dccp_pr_debug(format, a...)
47 #define dccp_pr_debug_cat(format, a...)
50 extern struct inet_hashinfo dccp_hashinfo;
52 extern atomic_t dccp_orphan_count;
54 extern void dccp_time_wait(struct sock *sk, int state, int timeo);
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
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)
69 #define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
70 * state, about 60 seconds */
72 /* RFC 1122, 4.2.3.1 initial RTO value */
73 #define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))
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).
82 #define DCCP_RTO_MAX ((unsigned)(64 * HZ))
85 * RTT sampling: sanity bounds and fallback RTT value from RFC 4340, section 3.4
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)
91 /* Maximal interval between probes for local resources. */
92 #define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))
94 /* sysctl variables for DCCP */
95 extern int sysctl_dccp_request_retries;
96 extern int sysctl_dccp_retries1;
97 extern int sysctl_dccp_retries2;
98 extern int sysctl_dccp_feat_sequence_window;
99 extern int sysctl_dccp_feat_rx_ccid;
100 extern int sysctl_dccp_feat_tx_ccid;
101 extern int sysctl_dccp_feat_ack_ratio;
102 extern int sysctl_dccp_feat_send_ack_vector;
103 extern int sysctl_dccp_feat_send_ndp_count;
104 extern int sysctl_dccp_tx_qlen;
105 extern int sysctl_dccp_sync_ratelimit;
108 * 48-bit sequence number arithmetic (signed and unsigned)
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))
118 static inline void dccp_set_seqno(u64 *seqno, u64 value)
120 *seqno = value & UINT48_MAX;
123 static inline void dccp_inc_seqno(u64 *seqno)
125 *seqno = ADD48(*seqno, 1);
128 /* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
129 static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
131 u64 delta = SUB48(seqno2, seqno1);
133 return TO_SIGNED48(delta);
136 /* is seq1 < seq2 ? */
137 static inline int before48(const u64 seq1, const u64 seq2)
139 return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
142 /* is seq1 > seq2 ? */
143 #define after48(seq1, seq2) before48(seq2, seq1)
145 /* is seq2 <= seq1 <= seq3 ? */
146 static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
148 return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
151 static inline u64 max48(const u64 seq1, const u64 seq2)
153 return after48(seq1, seq2) ? seq1 : seq2;
156 /* is seq1 next seqno after seq2 */
157 static inline int follows48(const u64 seq1, const u64 seq2)
159 return dccp_delta_seqno(seq2, seq1) == 1;
164 DCCP_MIB_ACTIVEOPENS, /* ActiveOpens */
165 DCCP_MIB_ESTABRESETS, /* EstabResets */
166 DCCP_MIB_CURRESTAB, /* CurrEstab */
167 DCCP_MIB_OUTSEGS, /* OutSegs */
169 DCCP_MIB_ABORTONTIMEOUT,
171 DCCP_MIB_ABORTFAILED,
172 DCCP_MIB_PASSIVEOPENS,
173 DCCP_MIB_ATTEMPTFAILS,
174 DCCP_MIB_OUTDATAGRAMS,
176 DCCP_MIB_OPTMANDATORYERROR,
181 #define DCCP_MIB_MAX __DCCP_MIB_MAX
183 unsigned long mibs[DCCP_MIB_MAX];
184 } __SNMP_MIB_ALIGN__;
186 DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
187 #define DCCP_INC_STATS(field) SNMP_INC_STATS(dccp_statistics, field)
188 #define DCCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(dccp_statistics, field)
189 #define DCCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(dccp_statistics, field)
190 #define DCCP_DEC_STATS(field) SNMP_DEC_STATS(dccp_statistics, field)
191 #define DCCP_ADD_STATS_BH(field, val) \
192 SNMP_ADD_STATS_BH(dccp_statistics, field, val)
193 #define DCCP_ADD_STATS_USER(field, val) \
194 SNMP_ADD_STATS_USER(dccp_statistics, field, val)
197 * Checksumming routines
199 static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb)
201 const struct dccp_hdr* dh = dccp_hdr(skb);
203 if (dh->dccph_cscov == 0)
205 return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
208 static inline void dccp_csum_outgoing(struct sk_buff *skb)
210 unsigned int cov = dccp_csum_coverage(skb);
213 dccp_hdr(skb)->dccph_cscov = 0;
215 skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
218 extern void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
220 extern int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb);
222 extern void dccp_send_ack(struct sock *sk);
223 extern void dccp_reqsk_send_ack(struct sk_buff *sk, struct request_sock *rsk);
225 extern void dccp_send_sync(struct sock *sk, const u64 seq,
226 const enum dccp_pkt_type pkt_type);
228 extern void dccp_write_xmit(struct sock *sk, int block);
229 extern void dccp_write_space(struct sock *sk);
231 extern void dccp_init_xmit_timers(struct sock *sk);
232 static inline void dccp_clear_xmit_timers(struct sock *sk)
234 inet_csk_clear_xmit_timers(sk);
237 extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
239 extern const char *dccp_packet_name(const int type);
240 extern const char *dccp_state_name(const int state);
242 extern void dccp_set_state(struct sock *sk, const int state);
243 extern void dccp_done(struct sock *sk);
245 extern void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb);
247 extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
249 extern struct sock *dccp_create_openreq_child(struct sock *sk,
250 const struct request_sock *req,
251 const struct sk_buff *skb);
253 extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
255 extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
257 struct request_sock *req,
258 struct dst_entry *dst);
259 extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
260 struct request_sock *req,
261 struct request_sock **prev);
263 extern int dccp_child_process(struct sock *parent, struct sock *child,
264 struct sk_buff *skb);
265 extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
266 struct dccp_hdr *dh, unsigned len);
267 extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
268 const struct dccp_hdr *dh, const unsigned len);
270 extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
271 extern int dccp_destroy_sock(struct sock *sk);
273 extern void dccp_close(struct sock *sk, long timeout);
274 extern struct sk_buff *dccp_make_response(struct sock *sk,
275 struct dst_entry *dst,
276 struct request_sock *req);
278 extern int dccp_connect(struct sock *sk);
279 extern int dccp_disconnect(struct sock *sk, int flags);
280 extern void dccp_hash(struct sock *sk);
281 extern void dccp_unhash(struct sock *sk);
282 extern int dccp_getsockopt(struct sock *sk, int level, int optname,
283 char __user *optval, int __user *optlen);
284 extern int dccp_setsockopt(struct sock *sk, int level, int optname,
285 char __user *optval, int optlen);
287 extern int compat_dccp_getsockopt(struct sock *sk,
288 int level, int optname,
289 char __user *optval, int __user *optlen);
290 extern int compat_dccp_setsockopt(struct sock *sk,
291 int level, int optname,
292 char __user *optval, int optlen);
294 extern int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
295 extern int dccp_sendmsg(struct kiocb *iocb, struct sock *sk,
296 struct msghdr *msg, size_t size);
297 extern int dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
298 struct msghdr *msg, size_t len, int nonblock,
299 int flags, int *addr_len);
300 extern void dccp_shutdown(struct sock *sk, int how);
301 extern int inet_dccp_listen(struct socket *sock, int backlog);
302 extern unsigned int dccp_poll(struct file *file, struct socket *sock,
304 extern int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
307 extern struct sk_buff *dccp_ctl_make_reset(struct socket *ctl,
308 struct sk_buff *skb);
309 extern int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
310 extern void dccp_send_close(struct sock *sk, const int active);
311 extern int dccp_invalid_packet(struct sk_buff *skb);
312 extern u32 dccp_sample_rtt(struct sock *sk, long delta);
314 static inline int dccp_bad_service_code(const struct sock *sk,
315 const __be32 service)
317 const struct dccp_sock *dp = dccp_sk(sk);
319 if (dp->dccps_service == service)
321 return !dccp_list_has_service(dp->dccps_service_list, service);
325 * dccp_skb_cb - DCCP per-packet control information
326 * @dccpd_type: one of %dccp_pkt_type (or unknown)
327 * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1
328 * @dccpd_reset_code: one of %dccp_reset_codes
329 * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code)
330 * @dccpd_opt_len: total length of all options (5.8) in the packet
331 * @dccpd_seq: sequence number
332 * @dccpd_ack_seq: acknowledgment number subheader field value
333 * This is used for transmission as well as for reception.
338 __u8 dccpd_reset_code,
345 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
347 /* RFC 4340, sec. 7.7 */
348 static inline int dccp_non_data_packet(const struct sk_buff *skb)
350 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
352 return type == DCCP_PKT_ACK ||
353 type == DCCP_PKT_CLOSE ||
354 type == DCCP_PKT_CLOSEREQ ||
355 type == DCCP_PKT_RESET ||
356 type == DCCP_PKT_SYNC ||
357 type == DCCP_PKT_SYNCACK;
360 /* RFC 4340, sec. 7.7 */
361 static inline int dccp_data_packet(const struct sk_buff *skb)
363 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
365 return type == DCCP_PKT_DATA ||
366 type == DCCP_PKT_DATAACK ||
367 type == DCCP_PKT_REQUEST ||
368 type == DCCP_PKT_RESPONSE;
371 static inline int dccp_packet_without_ack(const struct sk_buff *skb)
373 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
375 return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
378 #define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
380 static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
382 struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
385 dh->dccph_seq = htons((gss >> 32) & 0xfffff);
386 dhx->dccph_seq_low = htonl(gss & 0xffffffff);
389 static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
392 dhack->dccph_reserved1 = 0;
393 dhack->dccph_ack_nr_high = htons(gsr >> 32);
394 dhack->dccph_ack_nr_low = htonl(gsr & 0xffffffff);
397 static inline void dccp_update_gsr(struct sock *sk, u64 seq)
399 struct dccp_sock *dp = dccp_sk(sk);
400 const struct dccp_minisock *dmsk = dccp_msk(sk);
403 dccp_set_seqno(&dp->dccps_swl,
404 dp->dccps_gsr + 1 - (dmsk->dccpms_sequence_window / 4));
405 dccp_set_seqno(&dp->dccps_swh,
406 dp->dccps_gsr + (3 * dmsk->dccpms_sequence_window) / 4);
409 static inline void dccp_update_gss(struct sock *sk, u64 seq)
411 struct dccp_sock *dp = dccp_sk(sk);
413 dp->dccps_awh = dp->dccps_gss = seq;
414 dccp_set_seqno(&dp->dccps_awl,
416 dccp_msk(sk)->dccpms_sequence_window + 1));
419 static inline int dccp_ack_pending(const struct sock *sk)
421 const struct dccp_sock *dp = dccp_sk(sk);
422 return dp->dccps_timestamp_echo != 0 ||
423 #ifdef CONFIG_IP_DCCP_ACKVEC
424 (dccp_msk(sk)->dccpms_send_ack_vector &&
425 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
427 inet_csk_ack_scheduled(sk);
430 extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
431 extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);
432 extern int dccp_insert_option_elapsed_time(struct sock *sk,
435 extern u32 dccp_timestamp(void);
436 extern void dccp_timestamping_init(void);
437 extern int dccp_insert_option_timestamp(struct sock *sk,
438 struct sk_buff *skb);
439 extern int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
440 unsigned char option,
441 const void *value, unsigned char len);
444 extern int dccp_sysctl_init(void);
445 extern void dccp_sysctl_exit(void);
447 static inline int dccp_sysctl_init(void)
452 static inline void dccp_sysctl_exit(void)