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)
46 #define dccp_pr_debug(format, a...)
47 #define dccp_pr_debug_cat(format, a...)
50 extern struct inet_hashinfo dccp_hashinfo;
52 extern struct percpu_counter 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_tx_qlen;
99 extern int sysctl_dccp_sync_ratelimit;
102 * 48-bit sequence number arithmetic (signed and unsigned)
104 #define INT48_MIN 0x800000000000LL /* 2^47 */
105 #define UINT48_MAX 0xFFFFFFFFFFFFLL /* 2^48 - 1 */
106 #define COMPLEMENT48(x) (0x1000000000000LL - (x)) /* 2^48 - x */
107 #define TO_SIGNED48(x) (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x)))
108 #define TO_UNSIGNED48(x) (((x) >= 0)? (x) : COMPLEMENT48(-(x)))
109 #define ADD48(a, b) (((a) + (b)) & UINT48_MAX)
110 #define SUB48(a, b) ADD48((a), COMPLEMENT48(b))
112 static inline void dccp_set_seqno(u64 *seqno, u64 value)
114 *seqno = value & UINT48_MAX;
117 static inline void dccp_inc_seqno(u64 *seqno)
119 *seqno = ADD48(*seqno, 1);
122 /* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
123 static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
125 u64 delta = SUB48(seqno2, seqno1);
127 return TO_SIGNED48(delta);
130 /* is seq1 < seq2 ? */
131 static inline int before48(const u64 seq1, const u64 seq2)
133 return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
136 /* is seq1 > seq2 ? */
137 #define after48(seq1, seq2) before48(seq2, seq1)
139 /* is seq2 <= seq1 <= seq3 ? */
140 static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
142 return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
145 static inline u64 max48(const u64 seq1, const u64 seq2)
147 return after48(seq1, seq2) ? seq1 : seq2;
151 * dccp_loss_free - Evaluates condition for data loss from RFC 4340, 7.7.1
152 * @s1: start sequence number
153 * @s2: end sequence number
154 * @ndp: NDP count on packet with sequence number @s2
155 * Returns true if the sequence range s1...s2 has no data loss.
157 static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
159 s64 delta = dccp_delta_seqno(s1, s2);
162 return (u64)delta <= ndp + 1;
167 DCCP_MIB_ACTIVEOPENS, /* ActiveOpens */
168 DCCP_MIB_ESTABRESETS, /* EstabResets */
169 DCCP_MIB_CURRESTAB, /* CurrEstab */
170 DCCP_MIB_OUTSEGS, /* OutSegs */
172 DCCP_MIB_ABORTONTIMEOUT,
174 DCCP_MIB_ABORTFAILED,
175 DCCP_MIB_PASSIVEOPENS,
176 DCCP_MIB_ATTEMPTFAILS,
177 DCCP_MIB_OUTDATAGRAMS,
179 DCCP_MIB_OPTMANDATORYERROR,
184 #define DCCP_MIB_MAX __DCCP_MIB_MAX
186 unsigned long mibs[DCCP_MIB_MAX];
187 } __SNMP_MIB_ALIGN__;
189 DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
190 #define DCCP_INC_STATS(field) SNMP_INC_STATS(dccp_statistics, field)
191 #define DCCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(dccp_statistics, field)
192 #define DCCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(dccp_statistics, field)
193 #define DCCP_DEC_STATS(field) SNMP_DEC_STATS(dccp_statistics, field)
194 #define DCCP_ADD_STATS_BH(field, val) \
195 SNMP_ADD_STATS_BH(dccp_statistics, field, val)
196 #define DCCP_ADD_STATS_USER(field, val) \
197 SNMP_ADD_STATS_USER(dccp_statistics, field, val)
200 * Checksumming routines
202 static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb)
204 const struct dccp_hdr* dh = dccp_hdr(skb);
206 if (dh->dccph_cscov == 0)
208 return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
211 static inline void dccp_csum_outgoing(struct sk_buff *skb)
213 unsigned int cov = dccp_csum_coverage(skb);
216 dccp_hdr(skb)->dccph_cscov = 0;
218 skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
221 extern void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
223 extern int dccp_retransmit_skb(struct sock *sk);
225 extern void dccp_send_ack(struct sock *sk);
226 extern void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
227 struct request_sock *rsk);
229 extern void dccp_send_sync(struct sock *sk, const u64 seq,
230 const enum dccp_pkt_type pkt_type);
232 extern void dccp_write_xmit(struct sock *sk, int block);
233 extern void dccp_write_space(struct sock *sk);
235 extern void dccp_init_xmit_timers(struct sock *sk);
236 static inline void dccp_clear_xmit_timers(struct sock *sk)
238 inet_csk_clear_xmit_timers(sk);
241 extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
243 extern const char *dccp_packet_name(const int type);
244 extern const char *dccp_state_name(const int state);
246 extern void dccp_set_state(struct sock *sk, const int state);
247 extern void dccp_done(struct sock *sk);
249 extern int dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const *dp,
250 struct sk_buff const *skb);
252 extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
254 extern struct sock *dccp_create_openreq_child(struct sock *sk,
255 const struct request_sock *req,
256 const struct sk_buff *skb);
258 extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
260 extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
262 struct request_sock *req,
263 struct dst_entry *dst);
264 extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
265 struct request_sock *req,
266 struct request_sock **prev);
268 extern int dccp_child_process(struct sock *parent, struct sock *child,
269 struct sk_buff *skb);
270 extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
271 struct dccp_hdr *dh, unsigned len);
272 extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
273 const struct dccp_hdr *dh, const unsigned len);
275 extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
276 extern void dccp_destroy_sock(struct sock *sk);
278 extern void dccp_close(struct sock *sk, long timeout);
279 extern struct sk_buff *dccp_make_response(struct sock *sk,
280 struct dst_entry *dst,
281 struct request_sock *req);
283 extern int dccp_connect(struct sock *sk);
284 extern int dccp_disconnect(struct sock *sk, int flags);
285 extern int dccp_getsockopt(struct sock *sk, int level, int optname,
286 char __user *optval, int __user *optlen);
287 extern int dccp_setsockopt(struct sock *sk, int level, int optname,
288 char __user *optval, int optlen);
290 extern int compat_dccp_getsockopt(struct sock *sk,
291 int level, int optname,
292 char __user *optval, int __user *optlen);
293 extern int compat_dccp_setsockopt(struct sock *sk,
294 int level, int optname,
295 char __user *optval, int optlen);
297 extern int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
298 extern int dccp_sendmsg(struct kiocb *iocb, struct sock *sk,
299 struct msghdr *msg, size_t size);
300 extern int dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
301 struct msghdr *msg, size_t len, int nonblock,
302 int flags, int *addr_len);
303 extern void dccp_shutdown(struct sock *sk, int how);
304 extern int inet_dccp_listen(struct socket *sock, int backlog);
305 extern unsigned int dccp_poll(struct file *file, struct socket *sock,
307 extern int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
310 extern struct sk_buff *dccp_ctl_make_reset(struct sock *sk,
311 struct sk_buff *skb);
312 extern int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
313 extern void dccp_send_close(struct sock *sk, const int active);
314 extern int dccp_invalid_packet(struct sk_buff *skb);
315 extern u32 dccp_sample_rtt(struct sock *sk, long delta);
317 static inline int dccp_bad_service_code(const struct sock *sk,
318 const __be32 service)
320 const struct dccp_sock *dp = dccp_sk(sk);
322 if (dp->dccps_service == service)
324 return !dccp_list_has_service(dp->dccps_service_list, service);
328 * dccp_skb_cb - DCCP per-packet control information
329 * @dccpd_type: one of %dccp_pkt_type (or unknown)
330 * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1
331 * @dccpd_reset_code: one of %dccp_reset_codes
332 * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code)
333 * @dccpd_opt_len: total length of all options (5.8) in the packet
334 * @dccpd_seq: sequence number
335 * @dccpd_ack_seq: acknowledgment number subheader field value
336 * This is used for transmission as well as for reception.
340 struct inet_skb_parm h4;
341 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
342 struct inet6_skb_parm h6;
347 __u8 dccpd_reset_code,
354 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
356 /* RFC 4340, sec. 7.7 */
357 static inline int dccp_non_data_packet(const struct sk_buff *skb)
359 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
361 return type == DCCP_PKT_ACK ||
362 type == DCCP_PKT_CLOSE ||
363 type == DCCP_PKT_CLOSEREQ ||
364 type == DCCP_PKT_RESET ||
365 type == DCCP_PKT_SYNC ||
366 type == DCCP_PKT_SYNCACK;
369 /* RFC 4340, sec. 7.7 */
370 static inline int dccp_data_packet(const struct sk_buff *skb)
372 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
374 return type == DCCP_PKT_DATA ||
375 type == DCCP_PKT_DATAACK ||
376 type == DCCP_PKT_REQUEST ||
377 type == DCCP_PKT_RESPONSE;
380 static inline int dccp_packet_without_ack(const struct sk_buff *skb)
382 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
384 return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
387 #define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
389 static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
391 struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
394 dh->dccph_seq = htons((gss >> 32) & 0xfffff);
395 dhx->dccph_seq_low = htonl(gss & 0xffffffff);
398 static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
401 dhack->dccph_reserved1 = 0;
402 dhack->dccph_ack_nr_high = htons(gsr >> 32);
403 dhack->dccph_ack_nr_low = htonl(gsr & 0xffffffff);
406 static inline void dccp_update_gsr(struct sock *sk, u64 seq)
408 struct dccp_sock *dp = dccp_sk(sk);
411 /* Sequence validity window depends on remote Sequence Window (7.5.1) */
412 dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4);
413 dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4);
416 static inline void dccp_update_gss(struct sock *sk, u64 seq)
418 struct dccp_sock *dp = dccp_sk(sk);
421 /* Ack validity window depends on local Sequence Window value (7.5.1) */
422 dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win);
423 dp->dccps_awh = dp->dccps_gss;
426 static inline int dccp_ack_pending(const struct sock *sk)
428 const struct dccp_sock *dp = dccp_sk(sk);
429 return dp->dccps_timestamp_echo != 0 ||
430 (dp->dccps_hc_rx_ackvec != NULL &&
431 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
432 inet_csk_ack_scheduled(sk);
435 extern int dccp_feat_finalise_settings(struct dccp_sock *dp);
436 extern int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq);
437 extern int dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*,
438 struct sk_buff *skb);
439 extern int dccp_feat_activate_values(struct sock *sk, struct list_head *fn);
440 extern void dccp_feat_list_purge(struct list_head *fn_list);
442 extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
443 extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);
444 extern int dccp_insert_option_elapsed_time(struct sock *sk,
447 extern u32 dccp_timestamp(void);
448 extern void dccp_timestamping_init(void);
449 extern int dccp_insert_option_timestamp(struct sock *sk,
450 struct sk_buff *skb);
451 extern int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
452 unsigned char option,
453 const void *value, unsigned char len);
456 extern int dccp_sysctl_init(void);
457 extern void dccp_sysctl_exit(void);
459 static inline int dccp_sysctl_init(void)
464 static inline void dccp_sysctl_exit(void)