xref: /freebsd/contrib/unbound/services/outside_network.h (revision 7a789145f88a6aceacc59029a0cafe7de7aeefea)
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 struct shared_ports;
74 struct shared_ports_if;
75 
76 /**
77  * Send queries to outside servers and wait for answers from servers.
78  * Contains answer-listen sockets.
79  */
80 struct outside_network {
81 	/** Base for select calls */
82 	struct comm_base* base;
83 	/** pointer to time in seconds */
84 	time_t* now_secs;
85 	/** pointer to time in microseconds */
86 	struct timeval* now_tv;
87 
88 	/** buffer shared by UDP connections, since there is only one
89 	    datagram at any time. */
90 	struct sldns_buffer* udp_buff;
91 	/** serviced_callbacks malloc overhead when processing multiple
92 	 * identical serviced queries to the same server. */
93 	size_t svcd_overhead;
94 	/** use x20 bits to encode additional ID random bits */
95 	int use_caps_for_id;
96 	/** outside network wants to quit. Stop queued msgs from sent. */
97 	int want_to_quit;
98 
99 	/** number of unwanted replies received (for statistics) */
100 	size_t unwanted_replies;
101 	/** cumulative total of unwanted replies (for defense) */
102 	size_t unwanted_total;
103 	/** threshold when to take defensive action. If 0 then never. */
104 	size_t unwanted_threshold;
105 	/** what action to take, called when defensive action is needed */
106 	void (*unwanted_action)(void*);
107 	/** user param for action */
108 	void* unwanted_param;
109 
110 	/** linked list of available commpoints, unused file descriptors,
111 	 * for use as outgoing UDP ports. cp.fd=-1 in them. */
112 	struct port_comm* unused_fds;
113 	/** if udp is done */
114 	int do_udp;
115 	/** if udp is delay-closed (delayed answers do not meet closed port)*/
116 	int delayclose;
117 	/** timeout for delayclose */
118 	struct timeval delay_tv;
119 	/** if we perform udp-connect, connect() for UDP socket to mitigate
120 	 * ICMP side channel leakage */
121 	int udp_connect;
122 	/** number of udp packets sent. */
123 	size_t num_udp_outgoing;
124 	/** the shared ports structure, with random ports numbers.
125 	 * This is a reference to the member in the daemon structure. */
126 	struct shared_ports* shared_ports;
127 
128 	/** array of outgoing IP4 interfaces */
129 	struct port_if* ip4_ifs;
130 	/** number of outgoing IP4 interfaces */
131 	int num_ip4;
132 
133 	/** array of outgoing IP6 interfaces */
134 	struct port_if* ip6_ifs;
135 	/** number of outgoing IP6 interfaces */
136 	int num_ip6;
137 
138 	/** pending udp queries waiting to be sent out, waiting for fd */
139 	struct pending* udp_wait_first;
140 	/** last pending udp query in list */
141 	struct pending* udp_wait_last;
142 
143 	/** pending udp answers. sorted by id, addr */
144 	rbtree_type* pending;
145 	/** serviced queries, sorted by qbuf, addr, dnssec */
146 	rbtree_type* serviced;
147 	/** host cache, pointer but not owned by outnet. */
148 	struct infra_cache* infra;
149 	/** where to get random numbers */
150 	struct ub_randstate* rnd;
151 	/** ssl context to create ssl wrapped TCP with DNS connections */
152 	void* sslctx;
153 	/** if SNI will be used for TLS connections */
154 	int tls_use_sni;
155 #ifdef USE_DNSTAP
156 	/** dnstap environment */
157 	struct dt_env* dtenv;
158 #endif
159 	/** maximum segment size of tcp socket */
160 	int tcp_mss;
161 	/** IP_TOS socket option requested on the sockets */
162 	int ip_dscp;
163 
164 	/**
165 	 * Array of tcp pending used for outgoing TCP connections.
166 	 * Each can be used to establish a TCP connection with a server.
167 	 * The file descriptors are -1 if they are free, and need to be
168 	 * opened for the tcp connection. Can be used for ip4 and ip6.
169 	 */
170 	struct pending_tcp **tcp_conns;
171 	/** number of tcp communication points. */
172 	size_t num_tcp;
173 	/** number of tcp communication points in use. */
174 	size_t num_tcp_outgoing;
175 	/** max number of queries on a reuse connection */
176 	size_t max_reuse_tcp_queries;
177 	/** timeout for REUSE entries in milliseconds. */
178 	int tcp_reuse_timeout;
179 	/** timeout in milliseconds for TCP queries to auth servers. */
180 	int tcp_auth_query_timeout;
181 	/**
182 	 * tree of still-open and waiting tcp connections for reuse.
183 	 * can be closed and reopened to get a new tcp connection.
184 	 * or reused to the same destination again.  with timeout to close.
185 	 * Entries are of type struct reuse_tcp.
186 	 * The entries are both active and empty connections.
187 	 */
188 	rbtree_type tcp_reuse;
189 	/** max number of tcp_reuse entries we want to keep open */
190 	size_t tcp_reuse_max;
191 	/** first and last(oldest) in lru list of reuse connections.
192 	 * the oldest can be closed to get a new free pending_tcp if needed
193 	 * The list contains empty connections, that wait for timeout or
194 	 * a new query that can use the existing connection. */
195 	struct reuse_tcp* tcp_reuse_first, *tcp_reuse_last;
196 	/** list of tcp comm points that are free for use */
197 	struct pending_tcp* tcp_free;
198 	/** list of tcp queries waiting for a buffer */
199 	struct waiting_tcp* tcp_wait_first;
200 	/** last of waiting query list */
201 	struct waiting_tcp* tcp_wait_last;
202 };
203 
204 /**
205  * Outgoing interface. Ports available and currently used are tracked
206  * per interface
207  */
208 struct port_if {
209 	/** address ready to allocate new socket (except port no). */
210 	struct sockaddr_storage addr;
211 	/** length of addr field */
212 	socklen_t addrlen;
213 
214 	/** prefix length of network address (in bits), for randomisation.
215 	 * if 0, no randomisation. */
216 	int pfxlen;
217 
218 #ifndef DISABLE_EXPLICIT_PORT_RANDOMISATION
219 	/** the shared port numbers for this interface. */
220 	struct shared_ports_if* shpif;
221 #endif
222 
223 	/** array of the commpoints currently in use.
224 	 * allocated for max number of fds, first part in use. */
225 	struct port_comm** out;
226 	/** max number of fds, size of out array */
227 	int maxout;
228 	/** number of commpoints (and thus also ports) in use */
229 	int inuse;
230 };
231 
232 /**
233  * Outgoing commpoint for UDP port.
234  */
235 struct port_comm {
236 	/** next in free list */
237 	struct port_comm* next;
238 	/** which port number (when in use) */
239 	int number;
240 	/** interface it is used in */
241 	struct port_if* pif;
242 	/** index in the out array of the interface */
243 	int index;
244 	/** number of outstanding queries on this port */
245 	int num_outstanding;
246 	/** UDP commpoint, fd=-1 if not in use */
247 	struct comm_point* cp;
248 };
249 
250 /**
251  * Shared ports, the list of ports shared across threads
252  */
253 struct shared_ports {
254 	/** mutex on the ports */
255 	lock_basic_type lock;
256 	/** array of IP4 interfaces */
257 	struct shared_ports_if* ip4_ifs;
258 	/** number of outgoing IP4 interfaces */
259 	int num_ip4;
260 	/** array of IP6 interfaces */
261 	struct shared_ports_if* ip6_ifs;
262 	/** number of outgoing IP6 interfaces */
263 	int num_ip6;
264 };
265 
266 /**
267  * Shared ports for an interface.
268  */
269 struct shared_ports_if {
270 	/** address ready to allocate new socket (except port no). */
271 	struct sockaddr_storage addr;
272 	/** length of addr field */
273 	socklen_t addrlen;
274 	/** if a netblock, the prefix */
275 	int pfxlen;
276 
277 	/** the available ports array. These are unused.
278 	 * Only the first total-inuse part is filled. */
279 	int* avail_ports;
280 	/** the total number of available ports (size of the array) */
281 	int avail_total;
282 	/** the number in use. */
283 	int inuse;
284 };
285 
286 /**
287  * Reuse TCP connection, still open can be used again.
288  */
289 struct reuse_tcp {
290 	/** rbtree node with links in tcp_reuse tree. key is NULL when not
291 	 * in tree. Both active and empty connections are in the tree.
292 	 * key is a pointer to this structure, the members used to compare
293 	 * are the sockaddr and and then is-ssl bool, and then ptr value is
294 	 * used in case the same address exists several times in the tree
295 	 * when there are multiple connections to the same destination to
296 	 * make the rbtree items unique. */
297 	rbnode_type node;
298 	/** the key for the tcp_reuse tree. address of peer, ip4 or ip6,
299 	 * and port number of peer */
300 	struct sockaddr_storage addr;
301 	/** length of addr */
302 	socklen_t addrlen;
303 	/** also key for tcp_reuse tree, if ssl is used */
304 	int is_ssl;
305 	/** If is_ssl is enabled, tls_auth_name is part of the key for
306 	 * tcp_reuse tree. If the string is NULL, it without a tls_auth_name */
307 	char* tls_auth_name;
308 	/** lru chain, so that the oldest can be removed to get a new
309 	 * connection when all are in (re)use. oldest is last in list.
310 	 * The lru only contains empty connections waiting for reuse,
311 	 * the ones with active queries are not on the list because they
312 	 * do not need to be closed to make space for others.  They already
313 	 * service a query so the close for another query does not help
314 	 * service a larger number of queries. */
315 	struct reuse_tcp* lru_next, *lru_prev;
316 	/** true if the reuse_tcp item is on the lru list with empty items */
317 	int item_on_lru_list;
318 	/** the connection to reuse, the fd is non-1 and is open.
319 	 * the addr and port determine where the connection is going,
320 	 * and is key to the rbtree.  The SSL ptr determines if it is
321 	 * a TLS connection or a plain TCP connection there.  And TLS
322 	 * or not is also part of the key to the rbtree.
323 	 * There is a timeout and read event on the fd, to close it. */
324 	struct pending_tcp* pending;
325 	/**
326 	 * The more read again value pointed to by the commpoint
327 	 * tcp_more_read_again pointer, so that it exists after commpoint
328 	 * delete
329 	 */
330 	int cp_more_read_again;
331 	/**
332 	 * The more write again value pointed to by the commpoint
333 	 * tcp_more_write_again pointer, so that it exists after commpoint
334 	 * delete
335 	 */
336 	int cp_more_write_again;
337 	/** rbtree with other queries waiting on the connection, by ID number,
338 	 * of type struct waiting_tcp. It is for looking up received
339 	 * answers to the structure for callback.  And also to see if ID
340 	 * numbers are unused and can be used for a new query.
341 	 * The write_wait elements are also in the tree, so that ID numbers
342 	 * can be looked up also for them.  They are bool write_wait_queued. */
343 	rbtree_type tree_by_id;
344 	/** list of queries waiting to be written on the channel,
345 	 * if NULL no queries are waiting to be written and the pending->query
346 	 * is the query currently serviced.  The first is the next in line.
347 	 * They are also in the tree_by_id. Once written, the are removed
348 	 * from this list, but stay in the tree. */
349 	struct waiting_tcp* write_wait_first, *write_wait_last;
350 	/** the outside network it is part of */
351 	struct outside_network* outnet;
352 };
353 
354 /**
355  * A query that has an answer pending for it.
356  */
357 struct pending {
358 	/** redblacktree entry, key is the pending struct(id, addr). */
359 	rbnode_type node;
360 	/** the ID for the query. int so that a value out of range can
361 	 * be used to signify a pending that is for certain not present in
362 	 * the rbtree. (and for which deletion is safe). */
363 	unsigned int id;
364 	/** remote address. */
365 	struct sockaddr_storage addr;
366 	/** length of addr field in use. */
367 	socklen_t addrlen;
368 	/** comm point it was sent on (and reply must come back on). */
369 	struct port_comm* pc;
370 	/** timeout event */
371 	struct comm_timer* timer;
372 	/** callback for the timeout, error or reply to the message */
373 	comm_point_callback_type* cb;
374 	/** callback user argument */
375 	void* cb_arg;
376 	/** the outside network it is part of */
377 	struct outside_network* outnet;
378 	/** the corresponding serviced_query */
379 	struct serviced_query* sq;
380 
381 	/*---- filled if udp pending is waiting -----*/
382 	/** next in waiting list. */
383 	struct pending* next_waiting;
384 	/** timeout in msec */
385 	int timeout;
386 	/** The query itself, the query packet to send. */
387 	uint8_t* pkt;
388 	/** length of query packet. */
389 	size_t pkt_len;
390 };
391 
392 /**
393  * Pending TCP query to server.
394  */
395 struct pending_tcp {
396 	/** next in list of free tcp comm points, or NULL. */
397 	struct pending_tcp* next_free;
398 	/** port for of the outgoing interface that is used */
399 	struct port_if* pi;
400 	/** tcp comm point it was sent on (and reply must come back on). */
401 	struct comm_point* c;
402 	/** the query being serviced, NULL if the pending_tcp is unused. */
403 	struct waiting_tcp* query;
404 	/** the pre-allocated reuse tcp structure.  if ->pending is nonNULL
405 	 * it is in use and the connection is waiting for reuse.
406 	 * It is here for memory pre-allocation, and used to make this
407 	 * pending_tcp wait for reuse. */
408 	struct reuse_tcp reuse;
409 };
410 
411 /**
412  * Query waiting for TCP buffer.
413  */
414 struct waiting_tcp {
415 	/**
416 	 * next in waiting list.
417 	 * if on_tcp_waiting_list==0, this points to the pending_tcp structure.
418 	 */
419 	struct waiting_tcp* next_waiting;
420 	/** if true the item is on the tcp waiting list and next_waiting
421 	 * is used for that.  If false, the next_waiting points to the
422 	 * pending_tcp */
423 	int on_tcp_waiting_list;
424 	/** next and prev in query waiting list for stream connection */
425 	struct waiting_tcp* write_wait_prev, *write_wait_next;
426 	/** true if the waiting_tcp structure is on the write_wait queue */
427 	int write_wait_queued;
428 	/** entry in reuse.tree_by_id, if key is NULL, not in tree, otherwise,
429 	 * this struct is key and sorted by ID (from waiting_tcp.id). */
430 	rbnode_type id_node;
431 	/** the ID for the query; checked in reply */
432 	uint16_t id;
433 	/** timeout event; timer keeps running whether the query is
434 	 * waiting for a buffer or the tcp reply is pending */
435 	struct comm_timer* timer;
436 	/** timeout in msec */
437 	int timeout;
438 	/** the outside network it is part of */
439 	struct outside_network* outnet;
440 	/** remote address. */
441 	struct sockaddr_storage addr;
442 	/** length of addr field in use. */
443 	socklen_t addrlen;
444 	/**
445 	 * The query itself, the query packet to send.
446 	 * allocated after the waiting_tcp structure.
447 	 */
448 	uint8_t* pkt;
449 	/** length of query packet. */
450 	size_t pkt_len;
451 	/** callback for the timeout, error or reply to the message,
452 	 * or NULL if no user is waiting. the entry uses an ID number.
453 	 * a query that was written is no longer needed, but the ID number
454 	 * and a reply will come back and can be ignored if NULL */
455 	comm_point_callback_type* cb;
456 	/** callback user argument */
457 	void* cb_arg;
458 	/** if it uses ssl upstream */
459 	int ssl_upstream;
460 	/** owned copy of the tls_auth_name (malloced) */
461 	char* tls_auth_name;
462 	/** the packet was involved in an error, to stop looping errors */
463 	int error_count;
464 	/** if true, the item is at the cb_and_decommission stage */
465 	int in_cb_and_decommission;
466 #ifdef USE_DNSTAP
467 	/** serviced query pointer for dnstap to get logging info, if nonNULL*/
468 	struct serviced_query* sq;
469 #endif
470 };
471 
472 /**
473  * Callback to party interested in serviced query results.
474  */
475 struct service_callback {
476 	/** next in callback list */
477 	struct service_callback* next;
478 	/** callback function */
479 	comm_point_callback_type* cb;
480 	/** user argument for callback function */
481 	void* cb_arg;
482 };
483 
484 /** fallback size for fragmentation for EDNS in IPv4 */
485 #define EDNS_FRAG_SIZE_IP4 1472
486 /** fallback size for EDNS in IPv6, fits one fragment with ip6-tunnel-ids */
487 #define EDNS_FRAG_SIZE_IP6 1232
488 
489 /**
490  * Query service record.
491  * Contains query and destination. UDP, TCP, EDNS are all tried.
492  * complete with retries and timeouts. A number of interested parties can
493  * receive a callback.
494  */
495 struct serviced_query {
496 	/** The rbtree node, key is this record */
497 	rbnode_type node;
498 	/** The query that needs to be answered. Starts with flags u16,
499 	 * then qdcount, ..., including qname, qtype, qclass. Does not include
500 	 * EDNS record. */
501 	uint8_t* qbuf;
502 	/** length of qbuf. */
503 	size_t qbuflen;
504 	/** If an EDNS section is included, the DO/CD bit will be turned on. */
505 	int dnssec;
506 	/** We want signatures, or else the answer is likely useless */
507 	int want_dnssec;
508 	/** ignore capsforid */
509 	int nocaps;
510 	/** tcp upstream used, use tcp, or ssl_upstream for SSL */
511 	int tcp_upstream, ssl_upstream;
512 	/** the name of the tls authentication name, eg. 'ns.example.com'
513 	 * or NULL */
514 	char* tls_auth_name;
515 	/** where to send it */
516 	struct sockaddr_storage addr;
517 	/** length of addr field in use. */
518 	socklen_t addrlen;
519 	/** zone name, uncompressed domain name in wireformat */
520 	uint8_t* zone;
521 	/** length of zone name */
522 	size_t zonelen;
523 	/** qtype */
524 	int qtype;
525 	/** current status */
526 	enum serviced_query_status {
527 		/** initial status */
528 		serviced_initial,
529 		/** UDP with EDNS sent */
530 		serviced_query_UDP_EDNS,
531 		/** UDP without EDNS sent */
532 		serviced_query_UDP,
533 		/** TCP with EDNS sent */
534 		serviced_query_TCP_EDNS,
535 		/** TCP without EDNS sent */
536 		serviced_query_TCP,
537 		/** probe to test noEDNS0 (EDNS gives FORMERRorNOTIMP) */
538 		serviced_query_UDP_EDNS_fallback,
539 		/** probe to test TCP noEDNS0 (EDNS gives FORMERRorNOTIMP) */
540 		serviced_query_TCP_EDNS_fallback,
541 		/** send UDP query with EDNS1472 (or 1232) */
542 		serviced_query_UDP_EDNS_FRAG
543 	}
544 		/** variable with current status */
545 		status;
546 	/** true if serviced_query is scheduled for deletion already */
547 	int to_be_deleted;
548 	/** number of UDP retries */
549 	int retry;
550 	/** time last UDP was sent */
551 	struct timeval last_sent_time;
552 	/** rtt of last message */
553 	int last_rtt;
554 	/** do we know edns probe status already, for UDP_EDNS queries */
555 	int edns_lame_known;
556 	/** edns options to use for sending upstream packet */
557 	struct edns_option* opt_list;
558 	/** outside network this is part of */
559 	struct outside_network* outnet;
560 	/** list of interested parties that need callback on results. */
561 	struct service_callback* cblist;
562 	/** the UDP or TCP query that is pending, see status which */
563 	void* pending;
564 	/** block size with which to pad encrypted queries (default: 128) */
565 	size_t padding_block_size;
566 	/** region for this serviced query. Will be cleared when this
567 	 * serviced_query will be deleted */
568 	struct regional* region;
569 	/** allocation service for the region */
570 	struct alloc_cache* alloc;
571 	/** flash timer to start the net I/O as a separate event */
572 	struct comm_timer* timer;
573 	/** true if serviced_query is currently doing net I/O and may block */
574 	int busy;
575 };
576 
577 /**
578  * Create outside_network structure with N udp ports.
579  * @param base: the communication base to use for event handling.
580  * @param bufsize: size for network buffers.
581  * @param num_ports: number of udp ports to open per interface.
582  * @param ifs: interface names (or NULL for default interface).
583  *    These interfaces must be able to access all authoritative servers.
584  * @param num_ifs: number of names in array ifs.
585  * @param do_ip4: service IP4.
586  * @param do_ip6: service IP6.
587  * @param num_tcp: number of outgoing tcp buffers to preallocate.
588  * @param dscp: DSCP to use.
589  * @param infra: pointer to infra cached used for serviced queries.
590  * @param rnd: stored to create random numbers for serviced queries.
591  * @param use_caps_for_id: enable to use 0x20 bits to encode id randomness.
592  * @param unwanted_threshold: when to take defensive action.
593  * @param unwanted_action: the action to take.
594  * @param unwanted_param: user parameter to action.
595  * @param tcp_mss: maximum segment size of tcp socket.
596  * @param do_udp: if udp is done.
597  * @param sslctx: context to create outgoing connections with (if enabled).
598  * @param delayclose: if not 0, udp sockets are delayed before timeout closure.
599  * 	msec to wait on timeouted udp sockets.
600  * @param tls_use_sni: if SNI is used for TLS connections.
601  * @param dtenv: environment to send dnstap events with (if enabled).
602  * @param udp_connect: if the udp_connect option is enabled.
603  * @param max_reuse_tcp_queries: max number of queries on a reuse connection.
604  * @param tcp_reuse_timeout: timeout for REUSE entries in milliseconds.
605  * @param tcp_auth_query_timeout: timeout in milliseconds for TCP queries to auth servers.
606  * @param shared_ports: the shared_ports structure.
607  * @return: the new structure (with no pending answers) or NULL on error.
608  */
609 struct outside_network* outside_network_create(struct comm_base* base,
610 	size_t bufsize, size_t num_ports, char** ifs, int num_ifs,
611 	int do_ip4, int do_ip6, size_t num_tcp, int dscp, struct infra_cache* infra,
612 	struct ub_randstate* rnd, int use_caps_for_id,
613 	size_t unwanted_threshold, int tcp_mss,
614 	void (*unwanted_action)(void*), void* unwanted_param, int do_udp,
615 	void* sslctx, int delayclose, int tls_use_sni, struct dt_env *dtenv,
616 	int udp_connect, int max_reuse_tcp_queries, int tcp_reuse_timeout,
617 	int tcp_auth_query_timeout, struct shared_ports* shared_ports);
618 
619 /**
620  * Delete outside_network structure.
621  * @param outnet: object to delete.
622  */
623 void outside_network_delete(struct outside_network* outnet);
624 
625 /**
626  * Prepare for quit. Sends no more queries, even if queued up.
627  * @param outnet: object to prepare for removal
628  */
629 void outside_network_quit_prepare(struct outside_network* outnet);
630 
631 /**
632  * Send UDP query, create pending answer.
633  * Changes the ID for the query to be random and unique for that destination.
634  * @param sq: serviced query.
635  * @param packet: wireformat query to send to destination.
636  * @param timeout: in milliseconds from now.
637  * @param callback: function to call on error, timeout or reply.
638  * @param callback_arg: user argument for callback function.
639  * @return: NULL on error for malloc or socket. Else the pending query object.
640  */
641 struct pending* pending_udp_query(struct serviced_query* sq,
642 	struct sldns_buffer* packet, int timeout, comm_point_callback_type* callback,
643 	void* callback_arg);
644 
645 /**
646  * Send TCP query. May wait for TCP buffer. Selects ID to be random, and
647  * checks id.
648  * @param sq: serviced query.
649  * @param packet: wireformat query to send to destination. copied from.
650  * @param timeout: in milliseconds from now.
651  *    Timer starts running now. Timer may expire if all buffers are used,
652  *    without any query been sent to the server yet.
653  * @param callback: function to call on error, timeout or reply.
654  * @param callback_arg: user argument for callback function.
655  * @return: false on error for malloc or socket. Else the pending TCP object.
656  */
657 struct waiting_tcp* pending_tcp_query(struct serviced_query* sq,
658 	struct sldns_buffer* packet, int timeout, comm_point_callback_type* callback,
659 	void* callback_arg);
660 
661 /**
662  * Delete pending answer.
663  * @param outnet: outside network the pending query is part of.
664  *    Internal feature: if outnet is NULL, p is not unlinked from rbtree.
665  * @param p: deleted
666  */
667 void pending_delete(struct outside_network* outnet, struct pending* p);
668 
669 /**
670  * Perform a serviced query to the authoritative servers.
671  * Duplicate efforts are detected, and EDNS, TCP and UDP retry is performed.
672  * @param outnet: outside network, with rbtree of serviced queries.
673  * @param qinfo: query info.
674  * @param flags: flags u16 (host format), includes opcode, CD bit.
675  * @param dnssec: if set, DO bit is set in EDNS queries.
676  *	If the value includes BIT_CD, CD bit is set when in EDNS queries.
677  *	If the value includes BIT_DO, DO bit is set when in EDNS queries.
678  * @param want_dnssec: signatures are needed, without EDNS the answer is
679  * 	likely to be useless.
680  * @param nocaps: ignore use_caps_for_id and use unperturbed qname.
681  * @param check_ratelimit: if set, will check ratelimit before sending out.
682  * @param tcp_upstream: use TCP for upstream queries.
683  * @param ssl_upstream: use SSL for upstream queries.
684  * @param tls_auth_name: when ssl_upstream is true, use this name to check
685  * 	the server's peer certificate.
686  * @param addr: to which server to send the query.
687  * @param addrlen: length of addr.
688  * @param zone: name of the zone of the delegation point. wireformat dname.
689 	This is the delegation point name for which the server is deemed
690 	authoritative.
691  * @param zonelen: length of zone.
692  * @param qstate: module qstate. Mainly for inspecting the available
693  *	edns_opts_lists.
694  * @param callback: callback function.
695  * @param callback_arg: user argument to callback function.
696  * @param buff: scratch buffer to create query contents in. Empty on exit.
697  * @param env: the module environment.
698  * @param was_ratelimited: it will signal back if the query failed to pass the
699  *	ratelimit check.
700  * @param ratelimit_incremented: set to true if the ratelimit counter
701  *	was increased.
702  * @return 0 on error, or pointer to serviced query that is used to answer
703  *	this serviced query may be shared with other callbacks as well.
704  */
705 struct serviced_query* outnet_serviced_query(struct outside_network* outnet,
706 	struct query_info* qinfo, uint16_t flags, int dnssec, int want_dnssec,
707 	int nocaps, int check_ratelimit, int tcp_upstream, int ssl_upstream,
708 	char* tls_auth_name, struct sockaddr_storage* addr, socklen_t addrlen,
709 	uint8_t* zone, size_t zonelen, struct module_qstate* qstate,
710 	comm_point_callback_type* callback, void* callback_arg,
711 	struct sldns_buffer* buff, struct module_env* env, int* was_ratelimited,
712 	int* ratelimit_incremented);
713 
714 /**
715  * Remove service query callback.
716  * If that leads to zero callbacks, the query is completely cancelled.
717  * @param sq: serviced query to adjust.
718  * @param cb_arg: callback argument of callback that needs removal.
719  *	same as the callback_arg to outnet_serviced_query().
720  */
721 void outnet_serviced_query_stop(struct serviced_query* sq, void* cb_arg);
722 
723 /**
724  * Get memory size in use by outside network.
725  * Counts buffers and outstanding query (serviced queries) malloced data.
726  * @param outnet: outside network structure.
727  * @return size in bytes.
728  */
729 size_t outnet_get_mem(struct outside_network* outnet);
730 
731 /**
732  * Get memory size in use by serviced query while it is servicing callbacks.
733  * This takes into account the pre-deleted status of it; it will be deleted
734  * when the callbacks are done.
735  * @param sq: serviced query.
736  * @return size in bytes.
737  */
738 size_t serviced_get_mem(struct serviced_query* sq);
739 
740 /** Pick random ID value for a tcp stream, avoids existing IDs. */
741 uint16_t reuse_tcp_select_id(struct reuse_tcp* reuse,
742 	struct outside_network* outnet);
743 
744 /** find element in tree by id */
745 struct waiting_tcp* reuse_tcp_by_id_find(struct reuse_tcp* reuse, uint16_t id);
746 
747 /** insert element in tree by id */
748 void reuse_tree_by_id_insert(struct reuse_tcp* reuse, struct waiting_tcp* w);
749 
750 /** insert element in tcp_reuse tree and LRU list */
751 int reuse_tcp_insert(struct outside_network* outnet,
752 	struct pending_tcp* pend_tcp);
753 
754 /** touch the LRU of the element */
755 void reuse_tcp_lru_touch(struct outside_network* outnet,
756 	struct reuse_tcp* reuse);
757 
758 /** remove element from tree and LRU list */
759 void reuse_tcp_remove_tree_list(struct outside_network* outnet,
760 	struct reuse_tcp* reuse);
761 
762 /** snip the last reuse_tcp element off of the LRU list if any */
763 struct reuse_tcp* reuse_tcp_lru_snip(struct outside_network* outnet);
764 
765 /** delete readwait waiting_tcp elements, deletes the elements in the list */
766 void reuse_del_readwait(rbtree_type* tree_by_id);
767 
768 /** remove waiting tcp from the outnet waiting list */
769 void outnet_waiting_tcp_list_remove(struct outside_network* outnet,
770 	struct waiting_tcp* w);
771 
772 /** pop the first waiting tcp from the outnet waiting list */
773 struct waiting_tcp* outnet_waiting_tcp_list_pop(struct outside_network* outnet);
774 
775 /** add waiting_tcp element to the outnet tcp waiting list */
776 void outnet_waiting_tcp_list_add(struct outside_network* outnet,
777 	struct waiting_tcp* w, int set_timer);
778 
779 /** add waiting_tcp element as first to the outnet tcp waiting list */
780 void outnet_waiting_tcp_list_add_first(struct outside_network* outnet,
781 	struct waiting_tcp* w, int reset_timer);
782 
783 /** pop the first element from the writewait list */
784 struct waiting_tcp* reuse_write_wait_pop(struct reuse_tcp* reuse);
785 
786 /** remove the element from the writewait list */
787 void reuse_write_wait_remove(struct reuse_tcp* reuse, struct waiting_tcp* w);
788 
789 /** push the element after the last on the writewait list */
790 void reuse_write_wait_push_back(struct reuse_tcp* reuse, struct waiting_tcp* w);
791 
792 /** get TCP file descriptor for address, returns -1 on failure,
793  * tcp_mss is 0 or maxseg size to set for TCP packets,
794  * nodelay (TCP_NODELAY) should be set for TLS connections to speed up the TLS
795  * handshake.*/
796 int outnet_get_tcp_fd(struct sockaddr_storage* addr, socklen_t addrlen,
797 	int tcp_mss, int dscp, int nodelay);
798 
799 /**
800  * Create udp commpoint suitable for sending packets to the destination.
801  * @param outnet: outside_network with the comm_base it is attached to,
802  * 	with the outgoing interfaces chosen from, and rnd gen for random.
803  * @param cb: callback function for the commpoint.
804  * @param cb_arg: callback argument for cb.
805  * @param to_addr: intended destination.
806  * @param to_addrlen: length of to_addr.
807  * @return commpoint that you can comm_point_send_udp_msg with, or NULL.
808  */
809 struct comm_point* outnet_comm_point_for_udp(struct outside_network* outnet,
810 	comm_point_callback_type* cb, void* cb_arg,
811 	struct sockaddr_storage* to_addr, socklen_t to_addrlen);
812 
813 /**
814  * Create tcp commpoint suitable for communication to the destination.
815  * It also performs connect() to the to_addr.
816  * @param outnet: outside_network with the comm_base it is attached to,
817  * 	and the tcp_mss.
818  * @param cb: callback function for the commpoint.
819  * @param cb_arg: callback argument for cb.
820  * @param to_addr: intended destination.
821  * @param to_addrlen: length of to_addr.
822  * @param query: initial packet to send writing, in buffer.  It is copied
823  * 	to the commpoint buffer that is created.
824  * @param timeout: timeout for the TCP connection.
825  * 	timeout in milliseconds, or -1 for no (change to the) timeout.
826  *	So seconds*1000.
827  * @param ssl: set to true for TLS.
828  * @param host: hostname for host name verification of TLS (or NULL if no TLS).
829  * @return tcp_out commpoint, or NULL.
830  */
831 struct comm_point* outnet_comm_point_for_tcp(struct outside_network* outnet,
832 	comm_point_callback_type* cb, void* cb_arg,
833 	struct sockaddr_storage* to_addr, socklen_t to_addrlen,
834 	struct sldns_buffer* query, int timeout, int ssl, char* host);
835 
836 /**
837  * Create http commpoint suitable for communication to the destination.
838  * Creates the http request buffer. It also performs connect() to the to_addr.
839  * @param outnet: outside_network with the comm_base it is attached to,
840  * 	and the tcp_mss.
841  * @param cb: callback function for the commpoint.
842  * @param cb_arg: callback argument for cb.
843  * @param to_addr: intended destination.
844  * @param to_addrlen: length of to_addr.
845  * @param timeout: timeout for the TCP connection.
846  * 	timeout in milliseconds, or -1 for no (change to the) timeout.
847  *	So seconds*1000.
848  * @param ssl: set to true for https.
849  * @param host: hostname to use for the destination. part of http request.
850  * @param path: pathname to lookup, eg. name of the file on the destination.
851  * @param cfg: running configuration for User-Agent setup.
852  * @return http_out commpoint, or NULL.
853  */
854 struct comm_point* outnet_comm_point_for_http(struct outside_network* outnet,
855 	comm_point_callback_type* cb, void* cb_arg,
856 	struct sockaddr_storage* to_addr, socklen_t to_addrlen, int timeout,
857 	int ssl, char* host, char* path, struct config_file* cfg);
858 
859 /** connect tcp connection to addr, 0 on failure */
860 int outnet_tcp_connect(int s, struct sockaddr_storage* addr, socklen_t addrlen);
861 
862 /**
863  * Create new shared ports structure.
864  * @param ifs: interface names (or NULL for default interface).
865  *    These interfaces must be able to access all authoritative servers.
866  * @param num_ifs: number of names in array ifs.
867  * @param do_ip4: service IP4.
868  * @param do_ip6: service IP6.
869  * @param availports: array of available ports.
870  * @param numavailports: number of available ports in array.
871  * @return new, or NULL on failure.
872  */
873 struct shared_ports* shared_ports_create(char** ifs, int num_ifs, int do_ip4,
874 	int do_ip6, int* availports, int numavailports);
875 
876 /**
877  * Delete shared ports structure.
878  * @param shp: shared ports structure.
879  */
880 void shared_ports_delete(struct shared_ports* shp);
881 
882 /** Find interface in shared ports. */
883 struct shared_ports_if* shared_ports_find_if(struct shared_ports* shp,
884 	struct sockaddr_storage* addr, socklen_t addrlen, int pfxlen);
885 
886 /**
887  * Get a shared port from the list of random ports.
888  * @param shp: shared ports structure.
889  * @param shpif: the shared ports interface.
890  * @param rnd: used to make random numbers.
891  * @param udp_connect: set to true if no reuse is possible.
892  * @param reusenum: number of ports that can be reused (already open).
893  * @param port: the port number is returned.
894  * @param reused: if the port numer is reused, returned.
895  * @return false on failure. That can mean no more free ports to use.
896  */
897 int shared_ports_fetch_random(struct shared_ports* shp,
898 	struct shared_ports_if* shpif, struct ub_randstate* rnd,
899 	int udp_connect, int reusenum, int* port, int* reused);
900 
901 /**
902  * Return a shared port to the list of random ports.
903  * @param shp: shared ports structure.
904  * @param shpif: the shared ports interface.
905  * @param port: port number to return to be used again.
906  */
907 void shared_ports_return_port(struct shared_ports* shp,
908 	struct shared_ports_if* shpif, int port);
909 
910 /** callback for incoming udp answers from the network */
911 int outnet_udp_cb(struct comm_point* c, void* arg, int error,
912 	struct comm_reply *reply_info);
913 
914 /** callback for pending tcp connections */
915 int outnet_tcp_cb(struct comm_point* c, void* arg, int error,
916 	struct comm_reply *reply_info);
917 
918 /** callback for udp timeout */
919 void pending_udp_timer_cb(void *arg);
920 
921 /** callback for udp delay for timeout */
922 void pending_udp_timer_delay_cb(void *arg);
923 
924 /** callback for outgoing TCP timer event */
925 void outnet_tcptimer(void* arg);
926 
927 /** callback to send serviced queries */
928 void serviced_timer_cb(void *arg);
929 
930 /** callback for serviced query UDP answers */
931 int serviced_udp_callback(struct comm_point* c, void* arg, int error,
932         struct comm_reply* rep);
933 
934 /** TCP reply or error callback for serviced queries */
935 int serviced_tcp_callback(struct comm_point* c, void* arg, int error,
936         struct comm_reply* rep);
937 
938 /** compare function of pending rbtree */
939 int pending_cmp(const void* key1, const void* key2);
940 
941 /** compare function of serviced query rbtree */
942 int serviced_cmp(const void* key1, const void* key2);
943 
944 /** compare function of reuse_tcp rbtree in outside_network struct */
945 int reuse_cmp(const void* key1, const void* key2);
946 
947 /** compare function of reuse_tcp tree_by_id rbtree */
948 int reuse_id_cmp(const void* key1, const void* key2);
949 
950 #endif /* OUTSIDE_NETWORK_H */
951