xref: /freebsd/contrib/unbound/services/outside_network.h (revision 5fa84c6ec176d186ddad25d31f8760e50f48157f)
1 /*
2  * services/outside_network.h - listen to answers from the network
3  *
4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
5  *
6  * This software is open source.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * Redistributions of source code must retain the above copyright notice,
13  * this list of conditions and the following disclaimer.
14  *
15  * Redistributions in binary form must reproduce the above copyright notice,
16  * this list of conditions and the following disclaimer in the documentation
17  * and/or other materials provided with the distribution.
18  *
19  * Neither the name of the NLNET LABS nor the names of its contributors may
20  * be used to endorse or promote products derived from this software without
21  * specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34  */
35 
36 /**
37  * \file
38  *
39  * This file has functions to send queries to authoritative servers,
40  * and wait for the pending answer, with timeouts.
41  */
42 
43 #ifndef OUTSIDE_NETWORK_H
44 #define OUTSIDE_NETWORK_H
45 
46 #include "util/alloc.h"
47 #include "util/rbtree.h"
48 #include "util/regional.h"
49 #include "util/netevent.h"
50 #include "dnstap/dnstap_config.h"
51 #ifdef __QNX__
52 /* For struct timeval */
53 #include <sys/time.h>
54 #endif /* __QNX__ */
55 struct pending;
56 struct pending_timeout;
57 struct ub_randstate;
58 struct pending_tcp;
59 struct waiting_tcp;
60 struct waiting_udp;
61 struct reuse_tcp;
62 struct infra_cache;
63 struct port_comm;
64 struct port_if;
65 struct sldns_buffer;
66 struct serviced_query;
67 struct dt_env;
68 struct edns_option;
69 struct module_env;
70 struct module_qstate;
71 struct query_info;
72 struct config_file;
73 
74 /**
75  * Send queries to outside servers and wait for answers from servers.
76  * Contains answer-listen sockets.
77  */
78 struct outside_network {
79 	/** Base for select calls */
80 	struct comm_base* base;
81 	/** pointer to time in seconds */
82 	time_t* now_secs;
83 	/** pointer to time in microseconds */
84 	struct timeval* now_tv;
85 
86 	/** buffer shared by UDP connections, since there is only one
87 	    datagram at any time. */
88 	struct sldns_buffer* udp_buff;
89 	/** serviced_callbacks malloc overhead when processing multiple
90 	 * identical serviced queries to the same server. */
91 	size_t svcd_overhead;
92 	/** use x20 bits to encode additional ID random bits */
93 	int use_caps_for_id;
94 	/** outside network wants to quit. Stop queued msgs from sent. */
95 	int want_to_quit;
96 
97 	/** number of unwanted replies received (for statistics) */
98 	size_t unwanted_replies;
99 	/** cumulative total of unwanted replies (for defense) */
100 	size_t unwanted_total;
101 	/** threshold when to take defensive action. If 0 then never. */
102 	size_t unwanted_threshold;
103 	/** what action to take, called when defensive action is needed */
104 	void (*unwanted_action)(void*);
105 	/** user param for action */
106 	void* unwanted_param;
107 
108 	/** linked list of available commpoints, unused file descriptors,
109 	 * for use as outgoing UDP ports. cp.fd=-1 in them. */
110 	struct port_comm* unused_fds;
111 	/** if udp is done */
112 	int do_udp;
113 	/** if udp is delay-closed (delayed answers do not meet closed port)*/
114 	int delayclose;
115 	/** timeout for delayclose */
116 	struct timeval delay_tv;
117 	/** if we perform udp-connect, connect() for UDP socket to mitigate
118 	 * ICMP side channel leakage */
119 	int udp_connect;
120 	/** number of udp packets sent. */
121 	size_t num_udp_outgoing;
122 
123 	/** array of outgoing IP4 interfaces */
124 	struct port_if* ip4_ifs;
125 	/** number of outgoing IP4 interfaces */
126 	int num_ip4;
127 
128 	/** array of outgoing IP6 interfaces */
129 	struct port_if* ip6_ifs;
130 	/** number of outgoing IP6 interfaces */
131 	int num_ip6;
132 
133 	/** pending udp queries waiting to be sent out, waiting for fd */
134 	struct pending* udp_wait_first;
135 	/** last pending udp query in list */
136 	struct pending* udp_wait_last;
137 
138 	/** pending udp answers. sorted by id, addr */
139 	rbtree_type* pending;
140 	/** serviced queries, sorted by qbuf, addr, dnssec */
141 	rbtree_type* serviced;
142 	/** host cache, pointer but not owned by outnet. */
143 	struct infra_cache* infra;
144 	/** where to get random numbers */
145 	struct ub_randstate* rnd;
146 	/** ssl context to create ssl wrapped TCP with DNS connections */
147 	void* sslctx;
148 	/** if SNI will be used for TLS connections */
149 	int tls_use_sni;
150 #ifdef USE_DNSTAP
151 	/** dnstap environment */
152 	struct dt_env* dtenv;
153 #endif
154 	/** maximum segment size of tcp socket */
155 	int tcp_mss;
156 	/** IP_TOS socket option requested on the sockets */
157 	int ip_dscp;
158 
159 	/**
160 	 * Array of tcp pending used for outgoing TCP connections.
161 	 * Each can be used to establish a TCP connection with a server.
162 	 * The file descriptors are -1 if they are free, and need to be
163 	 * opened for the tcp connection. Can be used for ip4 and ip6.
164 	 */
165 	struct pending_tcp **tcp_conns;
166 	/** number of tcp communication points. */
167 	size_t num_tcp;
168 	/** number of tcp communication points in use. */
169 	size_t num_tcp_outgoing;
170 	/** max number of queries on a reuse connection */
171 	size_t max_reuse_tcp_queries;
172 	/** timeout for REUSE entries in milliseconds. */
173 	int tcp_reuse_timeout;
174 	/** timeout in milliseconds for TCP queries to auth servers. */
175 	int tcp_auth_query_timeout;
176 	/**
177 	 * tree of still-open and waiting tcp connections for reuse.
178 	 * can be closed and reopened to get a new tcp connection.
179 	 * or reused to the same destination again.  with timeout to close.
180 	 * Entries are of type struct reuse_tcp.
181 	 * The entries are both active and empty connections.
182 	 */
183 	rbtree_type tcp_reuse;
184 	/** max number of tcp_reuse entries we want to keep open */
185 	size_t tcp_reuse_max;
186 	/** first and last(oldest) in lru list of reuse connections.
187 	 * the oldest can be closed to get a new free pending_tcp if needed
188 	 * The list contains empty connections, that wait for timeout or
189 	 * a new query that can use the existing connection. */
190 	struct reuse_tcp* tcp_reuse_first, *tcp_reuse_last;
191 	/** list of tcp comm points that are free for use */
192 	struct pending_tcp* tcp_free;
193 	/** list of tcp queries waiting for a buffer */
194 	struct waiting_tcp* tcp_wait_first;
195 	/** last of waiting query list */
196 	struct waiting_tcp* tcp_wait_last;
197 };
198 
199 /**
200  * Outgoing interface. Ports available and currently used are tracked
201  * per interface
202  */
203 struct port_if {
204 	/** address ready to allocate new socket (except port no). */
205 	struct sockaddr_storage addr;
206 	/** length of addr field */
207 	socklen_t addrlen;
208 
209 	/** prefix length of network address (in bits), for randomisation.
210 	 * if 0, no randomisation. */
211 	int pfxlen;
212 
213 #ifndef DISABLE_EXPLICIT_PORT_RANDOMISATION
214 	/** the available ports array. These are unused.
215 	 * Only the first total-inuse part is filled. */
216 	int* avail_ports;
217 	/** the total number of available ports (size of the array) */
218 	int avail_total;
219 #endif
220 
221 	/** array of the commpoints currently in use.
222 	 * allocated for max number of fds, first part in use. */
223 	struct port_comm** out;
224 	/** max number of fds, size of out array */
225 	int maxout;
226 	/** number of commpoints (and thus also ports) in use */
227 	int inuse;
228 };
229 
230 /**
231  * Outgoing commpoint for UDP port.
232  */
233 struct port_comm {
234 	/** next in free list */
235 	struct port_comm* next;
236 	/** which port number (when in use) */
237 	int number;
238 	/** interface it is used in */
239 	struct port_if* pif;
240 	/** index in the out array of the interface */
241 	int index;
242 	/** number of outstanding queries on this port */
243 	int num_outstanding;
244 	/** UDP commpoint, fd=-1 if not in use */
245 	struct comm_point* cp;
246 };
247 
248 /**
249  * Reuse TCP connection, still open can be used again.
250  */
251 struct reuse_tcp {
252 	/** rbtree node with links in tcp_reuse tree. key is NULL when not
253 	 * in tree. Both active and empty connections are in the tree.
254 	 * key is a pointer to this structure, the members used to compare
255 	 * are the sockaddr and and then is-ssl bool, and then ptr value is
256 	 * used in case the same address exists several times in the tree
257 	 * when there are multiple connections to the same destination to
258 	 * make the rbtree items unique. */
259 	rbnode_type node;
260 	/** the key for the tcp_reuse tree. address of peer, ip4 or ip6,
261 	 * and port number of peer */
262 	struct sockaddr_storage addr;
263 	/** length of addr */
264 	socklen_t addrlen;
265 	/** also key for tcp_reuse tree, if ssl is used */
266 	int is_ssl;
267 	/** If is_ssl is enabled, tls_auth_name is part of the key for
268 	 * tcp_reuse tree. If the string is NULL, it without a tls_auth_name */
269 	char* tls_auth_name;
270 	/** lru chain, so that the oldest can be removed to get a new
271 	 * connection when all are in (re)use. oldest is last in list.
272 	 * The lru only contains empty connections waiting for reuse,
273 	 * the ones with active queries are not on the list because they
274 	 * do not need to be closed to make space for others.  They already
275 	 * service a query so the close for another query does not help
276 	 * service a larger number of queries. */
277 	struct reuse_tcp* lru_next, *lru_prev;
278 	/** true if the reuse_tcp item is on the lru list with empty items */
279 	int item_on_lru_list;
280 	/** the connection to reuse, the fd is non-1 and is open.
281 	 * the addr and port determine where the connection is going,
282 	 * and is key to the rbtree.  The SSL ptr determines if it is
283 	 * a TLS connection or a plain TCP connection there.  And TLS
284 	 * or not is also part of the key to the rbtree.
285 	 * There is a timeout and read event on the fd, to close it. */
286 	struct pending_tcp* pending;
287 	/**
288 	 * The more read again value pointed to by the commpoint
289 	 * tcp_more_read_again pointer, so that it exists after commpoint
290 	 * delete
291 	 */
292 	int cp_more_read_again;
293 	/**
294 	 * The more write again value pointed to by the commpoint
295 	 * tcp_more_write_again pointer, so that it exists after commpoint
296 	 * delete
297 	 */
298 	int cp_more_write_again;
299 	/** rbtree with other queries waiting on the connection, by ID number,
300 	 * of type struct waiting_tcp. It is for looking up received
301 	 * answers to the structure for callback.  And also to see if ID
302 	 * numbers are unused and can be used for a new query.
303 	 * The write_wait elements are also in the tree, so that ID numbers
304 	 * can be looked up also for them.  They are bool write_wait_queued. */
305 	rbtree_type tree_by_id;
306 	/** list of queries waiting to be written on the channel,
307 	 * if NULL no queries are waiting to be written and the pending->query
308 	 * is the query currently serviced.  The first is the next in line.
309 	 * They are also in the tree_by_id. Once written, the are removed
310 	 * from this list, but stay in the tree. */
311 	struct waiting_tcp* write_wait_first, *write_wait_last;
312 	/** the outside network it is part of */
313 	struct outside_network* outnet;
314 };
315 
316 /**
317  * A query that has an answer pending for it.
318  */
319 struct pending {
320 	/** redblacktree entry, key is the pending struct(id, addr). */
321 	rbnode_type node;
322 	/** the ID for the query. int so that a value out of range can
323 	 * be used to signify a pending that is for certain not present in
324 	 * the rbtree. (and for which deletion is safe). */
325 	unsigned int id;
326 	/** remote address. */
327 	struct sockaddr_storage addr;
328 	/** length of addr field in use. */
329 	socklen_t addrlen;
330 	/** comm point it was sent on (and reply must come back on). */
331 	struct port_comm* pc;
332 	/** timeout event */
333 	struct comm_timer* timer;
334 	/** callback for the timeout, error or reply to the message */
335 	comm_point_callback_type* cb;
336 	/** callback user argument */
337 	void* cb_arg;
338 	/** the outside network it is part of */
339 	struct outside_network* outnet;
340 	/** the corresponding serviced_query */
341 	struct serviced_query* sq;
342 
343 	/*---- filled if udp pending is waiting -----*/
344 	/** next in waiting list. */
345 	struct pending* next_waiting;
346 	/** timeout in msec */
347 	int timeout;
348 	/** The query itself, the query packet to send. */
349 	uint8_t* pkt;
350 	/** length of query packet. */
351 	size_t pkt_len;
352 };
353 
354 /**
355  * Pending TCP query to server.
356  */
357 struct pending_tcp {
358 	/** next in list of free tcp comm points, or NULL. */
359 	struct pending_tcp* next_free;
360 	/** port for of the outgoing interface that is used */
361 	struct port_if* pi;
362 	/** tcp comm point it was sent on (and reply must come back on). */
363 	struct comm_point* c;
364 	/** the query being serviced, NULL if the pending_tcp is unused. */
365 	struct waiting_tcp* query;
366 	/** the pre-allocated reuse tcp structure.  if ->pending is nonNULL
367 	 * it is in use and the connection is waiting for reuse.
368 	 * It is here for memory pre-allocation, and used to make this
369 	 * pending_tcp wait for reuse. */
370 	struct reuse_tcp reuse;
371 };
372 
373 /**
374  * Query waiting for TCP buffer.
375  */
376 struct waiting_tcp {
377 	/**
378 	 * next in waiting list.
379 	 * if on_tcp_waiting_list==0, this points to the pending_tcp structure.
380 	 */
381 	struct waiting_tcp* next_waiting;
382 	/** if true the item is on the tcp waiting list and next_waiting
383 	 * is used for that.  If false, the next_waiting points to the
384 	 * pending_tcp */
385 	int on_tcp_waiting_list;
386 	/** next and prev in query waiting list for stream connection */
387 	struct waiting_tcp* write_wait_prev, *write_wait_next;
388 	/** true if the waiting_tcp structure is on the write_wait queue */
389 	int write_wait_queued;
390 	/** entry in reuse.tree_by_id, if key is NULL, not in tree, otherwise,
391 	 * this struct is key and sorted by ID (from waiting_tcp.id). */
392 	rbnode_type id_node;
393 	/** the ID for the query; checked in reply */
394 	uint16_t id;
395 	/** timeout event; timer keeps running whether the query is
396 	 * waiting for a buffer or the tcp reply is pending */
397 	struct comm_timer* timer;
398 	/** timeout in msec */
399 	int timeout;
400 	/** the outside network it is part of */
401 	struct outside_network* outnet;
402 	/** remote address. */
403 	struct sockaddr_storage addr;
404 	/** length of addr field in use. */
405 	socklen_t addrlen;
406 	/**
407 	 * The query itself, the query packet to send.
408 	 * allocated after the waiting_tcp structure.
409 	 */
410 	uint8_t* pkt;
411 	/** length of query packet. */
412 	size_t pkt_len;
413 	/** callback for the timeout, error or reply to the message,
414 	 * or NULL if no user is waiting. the entry uses an ID number.
415 	 * a query that was written is no longer needed, but the ID number
416 	 * and a reply will come back and can be ignored if NULL */
417 	comm_point_callback_type* cb;
418 	/** callback user argument */
419 	void* cb_arg;
420 	/** if it uses ssl upstream */
421 	int ssl_upstream;
422 	/** ref to the tls_auth_name from the serviced_query */
423 	char* tls_auth_name;
424 	/** the packet was involved in an error, to stop looping errors */
425 	int error_count;
426 	/** if true, the item is at the cb_and_decommission stage */
427 	int in_cb_and_decommission;
428 #ifdef USE_DNSTAP
429 	/** serviced query pointer for dnstap to get logging info, if nonNULL*/
430 	struct serviced_query* sq;
431 #endif
432 };
433 
434 /**
435  * Callback to party interested in serviced query results.
436  */
437 struct service_callback {
438 	/** next in callback list */
439 	struct service_callback* next;
440 	/** callback function */
441 	comm_point_callback_type* cb;
442 	/** user argument for callback function */
443 	void* cb_arg;
444 };
445 
446 /** fallback size for fragmentation for EDNS in IPv4 */
447 #define EDNS_FRAG_SIZE_IP4 1472
448 /** fallback size for EDNS in IPv6, fits one fragment with ip6-tunnel-ids */
449 #define EDNS_FRAG_SIZE_IP6 1232
450 
451 /**
452  * Query service record.
453  * Contains query and destination. UDP, TCP, EDNS are all tried.
454  * complete with retries and timeouts. A number of interested parties can
455  * receive a callback.
456  */
457 struct serviced_query {
458 	/** The rbtree node, key is this record */
459 	rbnode_type node;
460 	/** The query that needs to be answered. Starts with flags u16,
461 	 * then qdcount, ..., including qname, qtype, qclass. Does not include
462 	 * EDNS record. */
463 	uint8_t* qbuf;
464 	/** length of qbuf. */
465 	size_t qbuflen;
466 	/** If an EDNS section is included, the DO/CD bit will be turned on. */
467 	int dnssec;
468 	/** We want signatures, or else the answer is likely useless */
469 	int want_dnssec;
470 	/** ignore capsforid */
471 	int nocaps;
472 	/** tcp upstream used, use tcp, or ssl_upstream for SSL */
473 	int tcp_upstream, ssl_upstream;
474 	/** the name of the tls authentication name, eg. 'ns.example.com'
475 	 * or NULL */
476 	char* tls_auth_name;
477 	/** where to send it */
478 	struct sockaddr_storage addr;
479 	/** length of addr field in use. */
480 	socklen_t addrlen;
481 	/** zone name, uncompressed domain name in wireformat */
482 	uint8_t* zone;
483 	/** length of zone name */
484 	size_t zonelen;
485 	/** qtype */
486 	int qtype;
487 	/** current status */
488 	enum serviced_query_status {
489 		/** initial status */
490 		serviced_initial,
491 		/** UDP with EDNS sent */
492 		serviced_query_UDP_EDNS,
493 		/** UDP without EDNS sent */
494 		serviced_query_UDP,
495 		/** TCP with EDNS sent */
496 		serviced_query_TCP_EDNS,
497 		/** TCP without EDNS sent */
498 		serviced_query_TCP,
499 		/** probe to test noEDNS0 (EDNS gives FORMERRorNOTIMP) */
500 		serviced_query_UDP_EDNS_fallback,
501 		/** probe to test TCP noEDNS0 (EDNS gives FORMERRorNOTIMP) */
502 		serviced_query_TCP_EDNS_fallback,
503 		/** send UDP query with EDNS1480 (or 1280) */
504 		serviced_query_UDP_EDNS_FRAG
505 	}
506 		/** variable with current status */
507 		status;
508 	/** true if serviced_query is scheduled for deletion already */
509 	int to_be_deleted;
510 	/** number of UDP retries */
511 	int retry;
512 	/** time last UDP was sent */
513 	struct timeval last_sent_time;
514 	/** rtt of last message */
515 	int last_rtt;
516 	/** do we know edns probe status already, for UDP_EDNS queries */
517 	int edns_lame_known;
518 	/** edns options to use for sending upstream packet */
519 	struct edns_option* opt_list;
520 	/** outside network this is part of */
521 	struct outside_network* outnet;
522 	/** list of interested parties that need callback on results. */
523 	struct service_callback* cblist;
524 	/** the UDP or TCP query that is pending, see status which */
525 	void* pending;
526 	/** block size with which to pad encrypted queries (default: 128) */
527 	size_t padding_block_size;
528 	/** region for this serviced query. Will be cleared when this
529 	 * serviced_query will be deleted */
530 	struct regional* region;
531 	/** allocation service for the region */
532 	struct alloc_cache* alloc;
533 	/** flash timer to start the net I/O as a separate event */
534 	struct comm_timer* timer;
535 	/** true if serviced_query is currently doing net I/O and may block */
536 	int busy;
537 };
538 
539 /**
540  * Create outside_network structure with N udp ports.
541  * @param base: the communication base to use for event handling.
542  * @param bufsize: size for network buffers.
543  * @param num_ports: number of udp ports to open per interface.
544  * @param ifs: interface names (or NULL for default interface).
545  *    These interfaces must be able to access all authoritative servers.
546  * @param num_ifs: number of names in array ifs.
547  * @param do_ip4: service IP4.
548  * @param do_ip6: service IP6.
549  * @param num_tcp: number of outgoing tcp buffers to preallocate.
550  * @param dscp: DSCP to use.
551  * @param infra: pointer to infra cached used for serviced queries.
552  * @param rnd: stored to create random numbers for serviced queries.
553  * @param use_caps_for_id: enable to use 0x20 bits to encode id randomness.
554  * @param availports: array of available ports.
555  * @param numavailports: number of available ports in array.
556  * @param unwanted_threshold: when to take defensive action.
557  * @param unwanted_action: the action to take.
558  * @param unwanted_param: user parameter to action.
559  * @param tcp_mss: maximum segment size of tcp socket.
560  * @param do_udp: if udp is done.
561  * @param sslctx: context to create outgoing connections with (if enabled).
562  * @param delayclose: if not 0, udp sockets are delayed before timeout closure.
563  * 	msec to wait on timeouted udp sockets.
564  * @param tls_use_sni: if SNI is used for TLS connections.
565  * @param dtenv: environment to send dnstap events with (if enabled).
566  * @param udp_connect: if the udp_connect option is enabled.
567  * @param max_reuse_tcp_queries: max number of queries on a reuse connection.
568  * @param tcp_reuse_timeout: timeout for REUSE entries in milliseconds.
569  * @param tcp_auth_query_timeout: timeout in milliseconds for TCP queries to auth servers.
570  * @return: the new structure (with no pending answers) or NULL on error.
571  */
572 struct outside_network* outside_network_create(struct comm_base* base,
573 	size_t bufsize, size_t num_ports, char** ifs, int num_ifs,
574 	int do_ip4, int do_ip6, size_t num_tcp, int dscp, struct infra_cache* infra,
575 	struct ub_randstate* rnd, int use_caps_for_id, int* availports,
576 	int numavailports, size_t unwanted_threshold, int tcp_mss,
577 	void (*unwanted_action)(void*), void* unwanted_param, int do_udp,
578 	void* sslctx, int delayclose, int tls_use_sni, struct dt_env *dtenv,
579 	int udp_connect, int max_reuse_tcp_queries, int tcp_reuse_timeout,
580 	int tcp_auth_query_timeout);
581 
582 /**
583  * Delete outside_network structure.
584  * @param outnet: object to delete.
585  */
586 void outside_network_delete(struct outside_network* outnet);
587 
588 /**
589  * Prepare for quit. Sends no more queries, even if queued up.
590  * @param outnet: object to prepare for removal
591  */
592 void outside_network_quit_prepare(struct outside_network* outnet);
593 
594 /**
595  * Send UDP query, create pending answer.
596  * Changes the ID for the query to be random and unique for that destination.
597  * @param sq: serviced query.
598  * @param packet: wireformat query to send to destination.
599  * @param timeout: in milliseconds from now.
600  * @param callback: function to call on error, timeout or reply.
601  * @param callback_arg: user argument for callback function.
602  * @return: NULL on error for malloc or socket. Else the pending query object.
603  */
604 struct pending* pending_udp_query(struct serviced_query* sq,
605 	struct sldns_buffer* packet, int timeout, comm_point_callback_type* callback,
606 	void* callback_arg);
607 
608 /**
609  * Send TCP query. May wait for TCP buffer. Selects ID to be random, and
610  * checks id.
611  * @param sq: serviced query.
612  * @param packet: wireformat query to send to destination. copied from.
613  * @param timeout: in milliseconds from now.
614  *    Timer starts running now. Timer may expire if all buffers are used,
615  *    without any query been sent to the server yet.
616  * @param callback: function to call on error, timeout or reply.
617  * @param callback_arg: user argument for callback function.
618  * @return: false on error for malloc or socket. Else the pending TCP object.
619  */
620 struct waiting_tcp* pending_tcp_query(struct serviced_query* sq,
621 	struct sldns_buffer* packet, int timeout, comm_point_callback_type* callback,
622 	void* callback_arg);
623 
624 /**
625  * Delete pending answer.
626  * @param outnet: outside network the pending query is part of.
627  *    Internal feature: if outnet is NULL, p is not unlinked from rbtree.
628  * @param p: deleted
629  */
630 void pending_delete(struct outside_network* outnet, struct pending* p);
631 
632 /**
633  * Perform a serviced query to the authoritative servers.
634  * Duplicate efforts are detected, and EDNS, TCP and UDP retry is performed.
635  * @param outnet: outside network, with rbtree of serviced queries.
636  * @param qinfo: query info.
637  * @param flags: flags u16 (host format), includes opcode, CD bit.
638  * @param dnssec: if set, DO bit is set in EDNS queries.
639  *	If the value includes BIT_CD, CD bit is set when in EDNS queries.
640  *	If the value includes BIT_DO, DO bit is set when in EDNS queries.
641  * @param want_dnssec: signatures are needed, without EDNS the answer is
642  * 	likely to be useless.
643  * @param nocaps: ignore use_caps_for_id and use unperturbed qname.
644  * @param check_ratelimit: if set, will check ratelimit before sending out.
645  * @param tcp_upstream: use TCP for upstream queries.
646  * @param ssl_upstream: use SSL for upstream queries.
647  * @param tls_auth_name: when ssl_upstream is true, use this name to check
648  * 	the server's peer certificate.
649  * @param addr: to which server to send the query.
650  * @param addrlen: length of addr.
651  * @param zone: name of the zone of the delegation point. wireformat dname.
652 	This is the delegation point name for which the server is deemed
653 	authoritative.
654  * @param zonelen: length of zone.
655  * @param qstate: module qstate. Mainly for inspecting the available
656  *	edns_opts_lists.
657  * @param callback: callback function.
658  * @param callback_arg: user argument to callback function.
659  * @param buff: scratch buffer to create query contents in. Empty on exit.
660  * @param env: the module environment.
661  * @param was_ratelimited: it will signal back if the query failed to pass the
662  *	ratelimit check.
663  * @return 0 on error, or pointer to serviced query that is used to answer
664  *	this serviced query may be shared with other callbacks as well.
665  */
666 struct serviced_query* outnet_serviced_query(struct outside_network* outnet,
667 	struct query_info* qinfo, uint16_t flags, int dnssec, int want_dnssec,
668 	int nocaps, int check_ratelimit, int tcp_upstream, int ssl_upstream,
669 	char* tls_auth_name, struct sockaddr_storage* addr, socklen_t addrlen,
670 	uint8_t* zone, size_t zonelen, struct module_qstate* qstate,
671 	comm_point_callback_type* callback, void* callback_arg,
672 	struct sldns_buffer* buff, struct module_env* env, int* was_ratelimited);
673 
674 /**
675  * Remove service query callback.
676  * If that leads to zero callbacks, the query is completely cancelled.
677  * @param sq: serviced query to adjust.
678  * @param cb_arg: callback argument of callback that needs removal.
679  *	same as the callback_arg to outnet_serviced_query().
680  */
681 void outnet_serviced_query_stop(struct serviced_query* sq, void* cb_arg);
682 
683 /**
684  * Get memory size in use by outside network.
685  * Counts buffers and outstanding query (serviced queries) malloced data.
686  * @param outnet: outside network structure.
687  * @return size in bytes.
688  */
689 size_t outnet_get_mem(struct outside_network* outnet);
690 
691 /**
692  * Get memory size in use by serviced query while it is servicing callbacks.
693  * This takes into account the pre-deleted status of it; it will be deleted
694  * when the callbacks are done.
695  * @param sq: serviced query.
696  * @return size in bytes.
697  */
698 size_t serviced_get_mem(struct serviced_query* sq);
699 
700 /** Pick random ID value for a tcp stream, avoids existing IDs. */
701 uint16_t reuse_tcp_select_id(struct reuse_tcp* reuse,
702 	struct outside_network* outnet);
703 
704 /** find element in tree by id */
705 struct waiting_tcp* reuse_tcp_by_id_find(struct reuse_tcp* reuse, uint16_t id);
706 
707 /** insert element in tree by id */
708 void reuse_tree_by_id_insert(struct reuse_tcp* reuse, struct waiting_tcp* w);
709 
710 /** insert element in tcp_reuse tree and LRU list */
711 int reuse_tcp_insert(struct outside_network* outnet,
712 	struct pending_tcp* pend_tcp);
713 
714 /** touch the LRU of the element */
715 void reuse_tcp_lru_touch(struct outside_network* outnet,
716 	struct reuse_tcp* reuse);
717 
718 /** remove element from tree and LRU list */
719 void reuse_tcp_remove_tree_list(struct outside_network* outnet,
720 	struct reuse_tcp* reuse);
721 
722 /** snip the last reuse_tcp element off of the LRU list if any */
723 struct reuse_tcp* reuse_tcp_lru_snip(struct outside_network* outnet);
724 
725 /** delete readwait waiting_tcp elements, deletes the elements in the list */
726 void reuse_del_readwait(rbtree_type* tree_by_id);
727 
728 /** remove waiting tcp from the outnet waiting list */
729 void outnet_waiting_tcp_list_remove(struct outside_network* outnet,
730 	struct waiting_tcp* w);
731 
732 /** pop the first waiting tcp from the outnet waiting list */
733 struct waiting_tcp* outnet_waiting_tcp_list_pop(struct outside_network* outnet);
734 
735 /** add waiting_tcp element to the outnet tcp waiting list */
736 void outnet_waiting_tcp_list_add(struct outside_network* outnet,
737 	struct waiting_tcp* w, int set_timer);
738 
739 /** add waiting_tcp element as first to the outnet tcp waiting list */
740 void outnet_waiting_tcp_list_add_first(struct outside_network* outnet,
741 	struct waiting_tcp* w, int reset_timer);
742 
743 /** pop the first element from the writewait list */
744 struct waiting_tcp* reuse_write_wait_pop(struct reuse_tcp* reuse);
745 
746 /** remove the element from the writewait list */
747 void reuse_write_wait_remove(struct reuse_tcp* reuse, struct waiting_tcp* w);
748 
749 /** push the element after the last on the writewait list */
750 void reuse_write_wait_push_back(struct reuse_tcp* reuse, struct waiting_tcp* w);
751 
752 /** get TCP file descriptor for address, returns -1 on failure,
753  * tcp_mss is 0 or maxseg size to set for TCP packets,
754  * nodelay (TCP_NODELAY) should be set for TLS connections to speed up the TLS
755  * handshake.*/
756 int outnet_get_tcp_fd(struct sockaddr_storage* addr, socklen_t addrlen,
757 	int tcp_mss, int dscp, int nodelay);
758 
759 /**
760  * Create udp commpoint suitable for sending packets to the destination.
761  * @param outnet: outside_network with the comm_base it is attached to,
762  * 	with the outgoing interfaces chosen from, and rnd gen for random.
763  * @param cb: callback function for the commpoint.
764  * @param cb_arg: callback argument for cb.
765  * @param to_addr: intended destination.
766  * @param to_addrlen: length of to_addr.
767  * @return commpoint that you can comm_point_send_udp_msg with, or NULL.
768  */
769 struct comm_point* outnet_comm_point_for_udp(struct outside_network* outnet,
770 	comm_point_callback_type* cb, void* cb_arg,
771 	struct sockaddr_storage* to_addr, socklen_t to_addrlen);
772 
773 /**
774  * Create tcp commpoint suitable for communication to the destination.
775  * It also performs connect() to the to_addr.
776  * @param outnet: outside_network with the comm_base it is attached to,
777  * 	and the tcp_mss.
778  * @param cb: callback function for the commpoint.
779  * @param cb_arg: callback argument for cb.
780  * @param to_addr: intended destination.
781  * @param to_addrlen: length of to_addr.
782  * @param query: initial packet to send writing, in buffer.  It is copied
783  * 	to the commpoint buffer that is created.
784  * @param timeout: timeout for the TCP connection.
785  * 	timeout in milliseconds, or -1 for no (change to the) timeout.
786  *	So seconds*1000.
787  * @param ssl: set to true for TLS.
788  * @param host: hostname for host name verification of TLS (or NULL if no TLS).
789  * @return tcp_out commpoint, or NULL.
790  */
791 struct comm_point* outnet_comm_point_for_tcp(struct outside_network* outnet,
792 	comm_point_callback_type* cb, void* cb_arg,
793 	struct sockaddr_storage* to_addr, socklen_t to_addrlen,
794 	struct sldns_buffer* query, int timeout, int ssl, char* host);
795 
796 /**
797  * Create http commpoint suitable for communication to the destination.
798  * Creates the http request buffer. It also performs connect() to the to_addr.
799  * @param outnet: outside_network with the comm_base it is attached to,
800  * 	and the tcp_mss.
801  * @param cb: callback function for the commpoint.
802  * @param cb_arg: callback argument for cb.
803  * @param to_addr: intended destination.
804  * @param to_addrlen: length of to_addr.
805  * @param timeout: timeout for the TCP connection.
806  * 	timeout in milliseconds, or -1 for no (change to the) timeout.
807  *	So seconds*1000.
808  * @param ssl: set to true for https.
809  * @param host: hostname to use for the destination. part of http request.
810  * @param path: pathname to lookup, eg. name of the file on the destination.
811  * @param cfg: running configuration for User-Agent setup.
812  * @return http_out commpoint, or NULL.
813  */
814 struct comm_point* outnet_comm_point_for_http(struct outside_network* outnet,
815 	comm_point_callback_type* cb, void* cb_arg,
816 	struct sockaddr_storage* to_addr, socklen_t to_addrlen, int timeout,
817 	int ssl, char* host, char* path, struct config_file* cfg);
818 
819 /** connect tcp connection to addr, 0 on failure */
820 int outnet_tcp_connect(int s, struct sockaddr_storage* addr, socklen_t addrlen);
821 
822 /** callback for incoming udp answers from the network */
823 int outnet_udp_cb(struct comm_point* c, void* arg, int error,
824 	struct comm_reply *reply_info);
825 
826 /** callback for pending tcp connections */
827 int outnet_tcp_cb(struct comm_point* c, void* arg, int error,
828 	struct comm_reply *reply_info);
829 
830 /** callback for udp timeout */
831 void pending_udp_timer_cb(void *arg);
832 
833 /** callback for udp delay for timeout */
834 void pending_udp_timer_delay_cb(void *arg);
835 
836 /** callback for outgoing TCP timer event */
837 void outnet_tcptimer(void* arg);
838 
839 /** callback to send serviced queries */
840 void serviced_timer_cb(void *arg);
841 
842 /** callback for serviced query UDP answers */
843 int serviced_udp_callback(struct comm_point* c, void* arg, int error,
844         struct comm_reply* rep);
845 
846 /** TCP reply or error callback for serviced queries */
847 int serviced_tcp_callback(struct comm_point* c, void* arg, int error,
848         struct comm_reply* rep);
849 
850 /** compare function of pending rbtree */
851 int pending_cmp(const void* key1, const void* key2);
852 
853 /** compare function of serviced query rbtree */
854 int serviced_cmp(const void* key1, const void* key2);
855 
856 /** compare function of reuse_tcp rbtree in outside_network struct */
857 int reuse_cmp(const void* key1, const void* key2);
858 
859 /** compare function of reuse_tcp tree_by_id rbtree */
860 int reuse_id_cmp(const void* key1, const void* key2);
861 
862 #endif /* OUTSIDE_NETWORK_H */
863