lsquic_engine.c revision 96f77e20
1/* Copyright (c) 2017 - 2018 LiteSpeed Technologies Inc.  See LICENSE. */
2/*
3 * lsquic_engine.c - QUIC engine
4 */
5
6#include <assert.h>
7#include <errno.h>
8#include <inttypes.h>
9#include <stdint.h>
10#include <stdio.h>
11#include <stdlib.h>
12#include <string.h>
13#include <sys/queue.h>
14#include <time.h>
15#ifndef WIN32
16#include <sys/time.h>
17#include <netinet/in.h>
18#include <sys/types.h>
19#include <sys/stat.h>
20#include <fcntl.h>
21#include <unistd.h>
22#include <netdb.h>
23#endif
24
25
26
27#include "lsquic.h"
28#include "lsquic_types.h"
29#include "lsquic_alarmset.h"
30#include "lsquic_parse.h"
31#include "lsquic_packet_in.h"
32#include "lsquic_packet_out.h"
33#include "lsquic_senhist.h"
34#include "lsquic_rtt.h"
35#include "lsquic_cubic.h"
36#include "lsquic_pacer.h"
37#include "lsquic_send_ctl.h"
38#include "lsquic_set.h"
39#include "lsquic_conn_flow.h"
40#include "lsquic_sfcw.h"
41#include "lsquic_stream.h"
42#include "lsquic_conn.h"
43#include "lsquic_full_conn.h"
44#include "lsquic_util.h"
45#include "lsquic_qtags.h"
46#include "lsquic_str.h"
47#include "lsquic_handshake.h"
48#include "lsquic_mm.h"
49#include "lsquic_conn_hash.h"
50#include "lsquic_engine_public.h"
51#include "lsquic_eng_hist.h"
52#include "lsquic_ev_log.h"
53#include "lsquic_version.h"
54#include "lsquic_hash.h"
55#include "lsquic_attq.h"
56#include "lsquic_min_heap.h"
57
58#define LSQUIC_LOGGER_MODULE LSQLM_ENGINE
59#include "lsquic_logger.h"
60
61
62/* The batch of outgoing packets grows and shrinks dynamically */
63#define MAX_OUT_BATCH_SIZE 1024
64#define MIN_OUT_BATCH_SIZE 256
65#define INITIAL_OUT_BATCH_SIZE 512
66
67struct out_batch
68{
69    lsquic_conn_t           *conns  [MAX_OUT_BATCH_SIZE];
70    lsquic_packet_out_t     *packets[MAX_OUT_BATCH_SIZE];
71    struct lsquic_out_spec   outs   [MAX_OUT_BATCH_SIZE];
72};
73
74typedef struct lsquic_conn * (*conn_iter_f)(struct lsquic_engine *);
75
76static void
77process_connections (struct lsquic_engine *engine, conn_iter_f iter,
78                     lsquic_time_t now);
79
80static void
81engine_incref_conn (lsquic_conn_t *conn, enum lsquic_conn_flags flag);
82
83static lsquic_conn_t *
84engine_decref_conn (lsquic_engine_t *engine, lsquic_conn_t *conn,
85                                        enum lsquic_conn_flags flag);
86
87static void
88force_close_conn (lsquic_engine_t *engine, lsquic_conn_t *conn);
89
90/* Nested calls to LSQUIC are not supported */
91#define ENGINE_IN(e) do {                               \
92    assert(!((e)->pub.enp_flags & ENPUB_PROC));         \
93    (e)->pub.enp_flags |= ENPUB_PROC;                   \
94} while (0)
95
96#define ENGINE_OUT(e) do {                              \
97    assert((e)->pub.enp_flags & ENPUB_PROC);            \
98    (e)->pub.enp_flags &= ~ENPUB_PROC;                  \
99} while (0)
100
101/* A connection can be referenced from one of six places:
102 *
103 *   1. Connection hash: a connection starts its life in one of those.
104 *
105 *   2. Outgoing queue.
106 *
107 *   3. Tickable queue
108 *
109 *   4. Advisory Tick Time queue.
110 *
111 *   5. Closing connections queue.  This is a transient queue -- it only
112 *      exists for the duration of process_connections() function call.
113 *
114 *   6. Ticked connections queue.  Another transient queue, similar to (5).
115 *
116 * The idea is to destroy the connection when it is no longer referenced.
117 * For example, a connection tick may return TICK_SEND|TICK_CLOSE.  In
118 * that case, the connection is referenced from two places: (2) and (5).
119 * After its packets are sent, it is only referenced in (5), and at the
120 * end of the function call, when it is removed from (5), reference count
121 * goes to zero and the connection is destroyed.  If not all packets can
122 * be sent, at the end of the function call, the connection is referenced
123 * by (2) and will only be removed once all outgoing packets have been
124 * sent.
125 */
126#define CONN_REF_FLAGS  (LSCONN_HASHED          \
127                        |LSCONN_HAS_OUTGOING    \
128                        |LSCONN_TICKABLE        \
129                        |LSCONN_TICKED          \
130                        |LSCONN_CLOSING         \
131                        |LSCONN_ATTQ)
132
133
134
135
136struct lsquic_engine
137{
138    struct lsquic_engine_public        pub;
139    enum {
140        ENG_SERVER      = LSENG_SERVER,
141        ENG_HTTP        = LSENG_HTTP,
142        ENG_COOLDOWN    = (1 <<  7),    /* Cooldown: no new connections */
143        ENG_PAST_DEADLINE
144                        = (1 <<  8),    /* Previous call to a processing
145                                         * function went past time threshold.
146                                         */
147#ifndef NDEBUG
148        ENG_DTOR        = (1 << 26),    /* Engine destructor */
149#endif
150    }                                  flags;
151    const struct lsquic_stream_if     *stream_if;
152    void                              *stream_if_ctx;
153    lsquic_packets_out_f               packets_out;
154    void                              *packets_out_ctx;
155    void                              *bad_handshake_ctx;
156    struct conn_hash                   conns_hash;
157    struct min_heap                    conns_tickable;
158    struct min_heap                    conns_out;
159    struct eng_hist                    history;
160    unsigned                           batch_size;
161    struct attq                       *attq;
162    /* Track time last time a packet was sent to give new connections
163     * priority lower than that of existing connections.
164     */
165    lsquic_time_t                      last_sent;
166    unsigned                           n_conns;
167    lsquic_time_t                      deadline;
168    struct out_batch                   out_batch;
169};
170
171
172void
173lsquic_engine_init_settings (struct lsquic_engine_settings *settings,
174                             unsigned flags)
175{
176    memset(settings, 0, sizeof(*settings));
177    settings->es_versions        = LSQUIC_DF_VERSIONS;
178    if (flags & ENG_SERVER)
179    {
180        settings->es_cfcw        = LSQUIC_DF_CFCW_SERVER;
181        settings->es_sfcw        = LSQUIC_DF_SFCW_SERVER;
182        settings->es_support_srej= LSQUIC_DF_SUPPORT_SREJ_SERVER;
183    }
184    else
185    {
186        settings->es_cfcw        = LSQUIC_DF_CFCW_CLIENT;
187        settings->es_sfcw        = LSQUIC_DF_SFCW_CLIENT;
188        settings->es_support_srej= LSQUIC_DF_SUPPORT_SREJ_CLIENT;
189    }
190    settings->es_max_streams_in  = LSQUIC_DF_MAX_STREAMS_IN;
191    settings->es_idle_conn_to    = LSQUIC_DF_IDLE_CONN_TO;
192    settings->es_handshake_to    = LSQUIC_DF_HANDSHAKE_TO;
193    settings->es_silent_close    = LSQUIC_DF_SILENT_CLOSE;
194    settings->es_max_header_list_size
195                                 = LSQUIC_DF_MAX_HEADER_LIST_SIZE;
196    settings->es_ua              = LSQUIC_DF_UA;
197
198    settings->es_pdmd            = QTAG_X509;
199    settings->es_aead            = QTAG_AESG;
200    settings->es_kexs            = QTAG_C255;
201    settings->es_support_push    = LSQUIC_DF_SUPPORT_PUSH;
202    settings->es_support_tcid0   = LSQUIC_DF_SUPPORT_TCID0;
203    settings->es_support_nstp    = LSQUIC_DF_SUPPORT_NSTP;
204    settings->es_honor_prst      = LSQUIC_DF_HONOR_PRST;
205    settings->es_progress_check  = LSQUIC_DF_PROGRESS_CHECK;
206    settings->es_rw_once         = LSQUIC_DF_RW_ONCE;
207    settings->es_proc_time_thresh= LSQUIC_DF_PROC_TIME_THRESH;
208    settings->es_pace_packets    = LSQUIC_DF_PACE_PACKETS;
209}
210
211
212/* Note: if returning an error, err_buf must be valid if non-NULL */
213int
214lsquic_engine_check_settings (const struct lsquic_engine_settings *settings,
215                              unsigned flags,
216                              char *err_buf, size_t err_buf_sz)
217{
218    if (settings->es_cfcw < LSQUIC_MIN_FCW ||
219        settings->es_sfcw < LSQUIC_MIN_FCW)
220    {
221        if (err_buf)
222            snprintf(err_buf, err_buf_sz, "%s",
223                                            "flow control window set too low");
224        return -1;
225    }
226    if (0 == (settings->es_versions & LSQUIC_SUPPORTED_VERSIONS))
227    {
228        if (err_buf)
229            snprintf(err_buf, err_buf_sz, "%s",
230                        "No supported QUIC versions specified");
231        return -1;
232    }
233    if (settings->es_versions & ~LSQUIC_SUPPORTED_VERSIONS)
234    {
235        if (err_buf)
236            snprintf(err_buf, err_buf_sz, "%s",
237                        "one or more unsupported QUIC version is specified");
238        return -1;
239    }
240    return 0;
241}
242
243
244static void
245free_packet (void *ctx, unsigned char *packet_data)
246{
247    free(packet_data);
248}
249
250
251static void *
252malloc_buf (void *ctx, size_t size)
253{
254    return malloc(size);
255}
256
257
258static const struct lsquic_packout_mem_if stock_pmi =
259{
260    malloc_buf, (void(*)(void *, void *)) free_packet,
261};
262
263
264lsquic_engine_t *
265lsquic_engine_new (unsigned flags,
266                   const struct lsquic_engine_api *api)
267{
268    lsquic_engine_t *engine;
269    int tag_buf_len;
270    char err_buf[100];
271
272    if (!api->ea_packets_out)
273    {
274        LSQ_ERROR("packets_out callback is not specified");
275        return NULL;
276    }
277
278    if (api->ea_settings &&
279                0 != lsquic_engine_check_settings(api->ea_settings, flags,
280                                                    err_buf, sizeof(err_buf)))
281    {
282        LSQ_ERROR("cannot create engine: %s", err_buf);
283        return NULL;
284    }
285
286    engine = calloc(1, sizeof(*engine));
287    if (!engine)
288        return NULL;
289    if (0 != lsquic_mm_init(&engine->pub.enp_mm))
290    {
291        free(engine);
292        return NULL;
293    }
294    if (api->ea_settings)
295        engine->pub.enp_settings        = *api->ea_settings;
296    else
297        lsquic_engine_init_settings(&engine->pub.enp_settings, flags);
298    tag_buf_len = gen_ver_tags(engine->pub.enp_ver_tags_buf,
299                                    sizeof(engine->pub.enp_ver_tags_buf),
300                                    engine->pub.enp_settings.es_versions);
301    if (tag_buf_len <= 0)
302    {
303        LSQ_ERROR("cannot generate version tags buffer");
304        free(engine);
305        return NULL;
306    }
307    engine->pub.enp_ver_tags_len = tag_buf_len;
308    engine->pub.enp_flags = ENPUB_CAN_SEND;
309
310    engine->flags           = flags;
311    engine->stream_if       = api->ea_stream_if;
312    engine->stream_if_ctx   = api->ea_stream_if_ctx;
313    engine->packets_out     = api->ea_packets_out;
314    engine->packets_out_ctx = api->ea_packets_out_ctx;
315    if (api->ea_pmi)
316    {
317        engine->pub.enp_pmi      = api->ea_pmi;
318        engine->pub.enp_pmi_ctx  = api->ea_pmi_ctx;
319    }
320    else
321    {
322        engine->pub.enp_pmi      = &stock_pmi;
323        engine->pub.enp_pmi_ctx  = NULL;
324    }
325    engine->pub.enp_engine = engine;
326    conn_hash_init(&engine->conns_hash, flags & ENG_SERVER);
327    engine->attq = attq_create();
328    eng_hist_init(&engine->history);
329    engine->batch_size = INITIAL_OUT_BATCH_SIZE;
330
331
332    LSQ_INFO("instantiated engine");
333    return engine;
334}
335
336
337static void
338grow_batch_size (struct lsquic_engine *engine)
339{
340    engine->batch_size <<= engine->batch_size < MAX_OUT_BATCH_SIZE;
341}
342
343
344static void
345shrink_batch_size (struct lsquic_engine *engine)
346{
347    engine->batch_size >>= engine->batch_size > MIN_OUT_BATCH_SIZE;
348}
349
350
351/* Wrapper to make sure important things occur before the connection is
352 * really destroyed.
353 */
354static void
355destroy_conn (struct lsquic_engine *engine, lsquic_conn_t *conn)
356{
357    --engine->n_conns;
358    conn->cn_flags |= LSCONN_NEVER_TICKABLE;
359    conn->cn_if->ci_destroy(conn);
360}
361
362
363static int
364maybe_grow_conn_heaps (struct lsquic_engine *engine)
365{
366    struct min_heap_elem *els;
367    unsigned count;
368
369    if (engine->n_conns < lsquic_mh_nalloc(&engine->conns_tickable))
370        return 0;   /* Nothing to do */
371
372    if (lsquic_mh_nalloc(&engine->conns_tickable))
373        count = lsquic_mh_nalloc(&engine->conns_tickable) * 2 * 2;
374    else
375        count = 8;
376
377    els = malloc(sizeof(els[0]) * count);
378    if (!els)
379    {
380        LSQ_ERROR("%s: malloc failed", __func__);
381        return -1;
382    }
383
384    LSQ_DEBUG("grew heaps to %u elements", count / 2);
385    memcpy(&els[0], engine->conns_tickable.mh_elems,
386                sizeof(els[0]) * lsquic_mh_count(&engine->conns_tickable));
387    memcpy(&els[count / 2], engine->conns_out.mh_elems,
388                sizeof(els[0]) * lsquic_mh_count(&engine->conns_out));
389    free(engine->conns_tickable.mh_elems);
390    engine->conns_tickable.mh_elems = els;
391    engine->conns_out.mh_elems = &els[count / 2];
392    engine->conns_tickable.mh_nalloc = count / 2;
393    engine->conns_out.mh_nalloc = count / 2;
394    return 0;
395}
396
397
398static lsquic_conn_t *
399new_full_conn_client (lsquic_engine_t *engine, const char *hostname,
400                      unsigned short max_packet_size)
401{
402    lsquic_conn_t *conn;
403    unsigned flags;
404    if (0 != maybe_grow_conn_heaps(engine))
405        return NULL;
406    flags = engine->flags & (ENG_SERVER|ENG_HTTP);
407    conn = full_conn_client_new(&engine->pub, engine->stream_if,
408                    engine->stream_if_ctx, flags, hostname, max_packet_size);
409    if (!conn)
410        return NULL;
411    ++engine->n_conns;
412    return conn;
413}
414
415
416static lsquic_conn_t *
417find_conn (lsquic_engine_t *engine, lsquic_packet_in_t *packet_in,
418         struct packin_parse_state *ppstate, const struct sockaddr *sa_local)
419{
420    lsquic_conn_t *conn;
421
422    conn = conn_hash_find_by_addr(&engine->conns_hash, sa_local);
423    if (!conn)
424        return NULL;
425
426    conn->cn_pf->pf_parse_packet_in_finish(packet_in, ppstate);
427    if ((packet_in->pi_flags & PI_CONN_ID)
428        && conn->cn_cid != packet_in->pi_conn_id)
429    {
430        LSQ_DEBUG("connection IDs do not match");
431        return NULL;
432    }
433
434    return conn;
435}
436
437
438#if !defined(NDEBUG) && __GNUC__
439__attribute__((weak))
440#endif
441void
442lsquic_engine_add_conn_to_tickable (struct lsquic_engine_public *enpub,
443                                    lsquic_conn_t *conn)
444{
445    if (0 == (enpub->enp_flags & ENPUB_PROC) &&
446        0 == (conn->cn_flags & (LSCONN_TICKABLE|LSCONN_NEVER_TICKABLE)))
447    {
448        lsquic_engine_t *engine = (lsquic_engine_t *) enpub;
449        lsquic_mh_insert(&engine->conns_tickable, conn, conn->cn_last_ticked);
450        engine_incref_conn(conn, LSCONN_TICKABLE);
451    }
452}
453
454
455void
456lsquic_engine_add_conn_to_attq (struct lsquic_engine_public *enpub,
457                                lsquic_conn_t *conn, lsquic_time_t tick_time)
458{
459    lsquic_engine_t *const engine = (lsquic_engine_t *) enpub;
460    if (conn->cn_flags & LSCONN_TICKABLE)
461    {
462        /* Optimization: no need to add the connection to the Advisory Tick
463         * Time Queue: it is about to be ticked, after which it its next tick
464         * time may be queried again.
465         */;
466    }
467    else if (conn->cn_flags & LSCONN_ATTQ)
468    {
469        if (lsquic_conn_adv_time(conn) != tick_time)
470        {
471            attq_remove(engine->attq, conn);
472            if (0 != attq_add(engine->attq, conn, tick_time))
473                engine_decref_conn(engine, conn, LSCONN_ATTQ);
474        }
475    }
476    else if (0 == attq_add(engine->attq, conn, tick_time))
477        engine_incref_conn(conn, LSCONN_ATTQ);
478}
479
480
481/* Return 0 if packet is being processed by a connections, otherwise return 1 */
482static int
483process_packet_in (lsquic_engine_t *engine, lsquic_packet_in_t *packet_in,
484       struct packin_parse_state *ppstate, const struct sockaddr *sa_local,
485       const struct sockaddr *sa_peer, void *peer_ctx)
486{
487    lsquic_conn_t *conn;
488
489    if (lsquic_packet_in_is_prst(packet_in)
490                                && !engine->pub.enp_settings.es_honor_prst)
491    {
492        lsquic_mm_put_packet_in(&engine->pub.enp_mm, packet_in);
493        LSQ_DEBUG("public reset packet: discarding");
494        return 1;
495    }
496
497    conn = find_conn(engine, packet_in, ppstate, sa_local);
498
499    if (!conn)
500    {
501        lsquic_mm_put_packet_in(&engine->pub.enp_mm, packet_in);
502        return 1;
503    }
504
505    if (0 == (conn->cn_flags & LSCONN_TICKABLE))
506    {
507        lsquic_mh_insert(&engine->conns_tickable, conn, conn->cn_last_ticked);
508        engine_incref_conn(conn, LSCONN_TICKABLE);
509    }
510    lsquic_conn_record_sockaddr(conn, sa_local, sa_peer);
511    lsquic_packet_in_upref(packet_in);
512    conn->cn_peer_ctx = peer_ctx;
513    conn->cn_if->ci_packet_in(conn, packet_in);
514    lsquic_packet_in_put(&engine->pub.enp_mm, packet_in);
515    return 0;
516}
517
518
519void
520lsquic_engine_destroy (lsquic_engine_t *engine)
521{
522    lsquic_conn_t *conn;
523
524    LSQ_DEBUG("destroying engine");
525#ifndef NDEBUG
526    engine->flags |= ENG_DTOR;
527#endif
528
529    while ((conn = lsquic_mh_pop(&engine->conns_out)))
530    {
531        assert(conn->cn_flags & LSCONN_HAS_OUTGOING);
532        (void) engine_decref_conn(engine, conn, LSCONN_HAS_OUTGOING);
533    }
534
535    while ((conn = lsquic_mh_pop(&engine->conns_tickable)))
536    {
537        assert(conn->cn_flags & LSCONN_TICKABLE);
538        (void) engine_decref_conn(engine, conn, LSCONN_TICKABLE);
539    }
540
541    for (conn = conn_hash_first(&engine->conns_hash); conn;
542                            conn = conn_hash_next(&engine->conns_hash))
543        force_close_conn(engine, conn);
544    conn_hash_cleanup(&engine->conns_hash);
545
546    assert(0 == engine->n_conns);
547    attq_destroy(engine->attq);
548
549    assert(0 == lsquic_mh_count(&engine->conns_out));
550    assert(0 == lsquic_mh_count(&engine->conns_tickable));
551    free(engine->conns_tickable.mh_elems);
552    free(engine);
553}
554
555
556lsquic_conn_t *
557lsquic_engine_connect (lsquic_engine_t *engine, const struct sockaddr *local_sa,
558                       const struct sockaddr *peer_sa,
559                       void *peer_ctx, lsquic_conn_ctx_t *conn_ctx,
560                       const char *hostname, unsigned short max_packet_size)
561{
562    lsquic_conn_t *conn;
563    ENGINE_IN(engine);
564
565    if (engine->flags & ENG_SERVER)
566    {
567        LSQ_ERROR("`%s' must only be called in client mode", __func__);
568        goto err;
569    }
570
571    if (0 == max_packet_size)
572    {
573        switch (peer_sa->sa_family)
574        {
575        case AF_INET:
576            max_packet_size = QUIC_MAX_IPv4_PACKET_SZ;
577            break;
578        default:
579            max_packet_size = QUIC_MAX_IPv6_PACKET_SZ;
580            break;
581        }
582    }
583
584    conn = new_full_conn_client(engine, hostname, max_packet_size);
585    if (!conn)
586        goto err;
587    lsquic_conn_record_sockaddr(conn, local_sa, peer_sa);
588    if (0 != conn_hash_add(&engine->conns_hash, conn))
589    {
590        LSQ_WARN("cannot add connection %"PRIu64" to hash - destroy",
591            conn->cn_cid);
592        destroy_conn(engine, conn);
593        goto err;
594    }
595    assert(!(conn->cn_flags &
596        (CONN_REF_FLAGS
597         & ~LSCONN_TICKABLE /* This flag may be set as effect of user
598                                 callbacks */
599                             )));
600    conn->cn_flags |= LSCONN_HASHED;
601    lsquic_mh_insert(&engine->conns_tickable, conn, conn->cn_last_ticked);
602    engine_incref_conn(conn, LSCONN_TICKABLE);
603    conn->cn_peer_ctx = peer_ctx;
604    lsquic_conn_set_ctx(conn, conn_ctx);
605    full_conn_client_call_on_new(conn);
606  end:
607    ENGINE_OUT(engine);
608    return conn;
609  err:
610    conn = NULL;
611    goto end;
612}
613
614
615static void
616remove_conn_from_hash (lsquic_engine_t *engine, lsquic_conn_t *conn)
617{
618    conn_hash_remove(&engine->conns_hash, conn);
619    (void) engine_decref_conn(engine, conn, LSCONN_HASHED);
620}
621
622
623static void
624refflags2str (enum lsquic_conn_flags flags, char s[6])
625{
626    *s = 'C'; s += !!(flags & LSCONN_CLOSING);
627    *s = 'H'; s += !!(flags & LSCONN_HASHED);
628    *s = 'O'; s += !!(flags & LSCONN_HAS_OUTGOING);
629    *s = 'T'; s += !!(flags & LSCONN_TICKABLE);
630    *s = 'A'; s += !!(flags & LSCONN_ATTQ);
631    *s = 'K'; s += !!(flags & LSCONN_TICKED);
632    *s = '\0';
633}
634
635
636static void
637engine_incref_conn (lsquic_conn_t *conn, enum lsquic_conn_flags flag)
638{
639    char str[2][7];
640    assert(flag & CONN_REF_FLAGS);
641    assert(!(conn->cn_flags & flag));
642    conn->cn_flags |= flag;
643    LSQ_DEBUG("incref conn %"PRIu64", '%s' -> '%s'", conn->cn_cid,
644                    (refflags2str(conn->cn_flags & ~flag, str[0]), str[0]),
645                    (refflags2str(conn->cn_flags, str[1]), str[1]));
646}
647
648
649static lsquic_conn_t *
650engine_decref_conn (lsquic_engine_t *engine, lsquic_conn_t *conn,
651                                        enum lsquic_conn_flags flags)
652{
653    char str[2][7];
654    assert(flags & CONN_REF_FLAGS);
655    assert(conn->cn_flags & flags);
656#ifndef NDEBUG
657    if (flags & LSCONN_CLOSING)
658        assert(0 == (conn->cn_flags & LSCONN_HASHED));
659#endif
660    conn->cn_flags &= ~flags;
661    LSQ_DEBUG("decref conn %"PRIu64", '%s' -> '%s'", conn->cn_cid,
662                    (refflags2str(conn->cn_flags | flags, str[0]), str[0]),
663                    (refflags2str(conn->cn_flags, str[1]), str[1]));
664    if (0 == (conn->cn_flags & CONN_REF_FLAGS))
665    {
666        eng_hist_inc(&engine->history, 0, sl_del_full_conns);
667        destroy_conn(engine, conn);
668        return NULL;
669    }
670    else
671        return conn;
672}
673
674
675/* This is not a general-purpose function.  Only call from engine dtor. */
676static void
677force_close_conn (lsquic_engine_t *engine, lsquic_conn_t *conn)
678{
679    assert(engine->flags & ENG_DTOR);
680    const enum lsquic_conn_flags flags = conn->cn_flags;
681    assert(conn->cn_flags & CONN_REF_FLAGS);
682    assert(!(flags & LSCONN_HAS_OUTGOING));  /* Should be removed already */
683    assert(!(flags & LSCONN_TICKABLE));    /* Should be removed already */
684    assert(!(flags & LSCONN_CLOSING));  /* It is in transient queue? */
685    if (flags & LSCONN_ATTQ)
686    {
687        attq_remove(engine->attq, conn);
688        (void) engine_decref_conn(engine, conn, LSCONN_ATTQ);
689    }
690    if (flags & LSCONN_HASHED)
691        remove_conn_from_hash(engine, conn);
692}
693
694
695/* Iterator for tickable connections (those on the Tickable Queue).  Before
696 * a connection is returned, it is removed from the Advisory Tick Time queue
697 * if necessary.
698 */
699static lsquic_conn_t *
700conn_iter_next_tickable (struct lsquic_engine *engine)
701{
702    lsquic_conn_t *conn;
703
704    conn = lsquic_mh_pop(&engine->conns_tickable);
705
706    if (conn)
707        conn = engine_decref_conn(engine, conn, LSCONN_TICKABLE);
708    if (conn && (conn->cn_flags & LSCONN_ATTQ))
709    {
710        attq_remove(engine->attq, conn);
711        conn = engine_decref_conn(engine, conn, LSCONN_ATTQ);
712    }
713
714    return conn;
715}
716
717
718void
719lsquic_engine_process_conns (lsquic_engine_t *engine)
720{
721    lsquic_conn_t *conn;
722    lsquic_time_t now;
723
724    ENGINE_IN(engine);
725
726    now = lsquic_time_now();
727    while ((conn = attq_pop(engine->attq, now)))
728    {
729        conn = engine_decref_conn(engine, conn, LSCONN_ATTQ);
730        if (conn && !(conn->cn_flags & LSCONN_TICKABLE))
731        {
732            lsquic_mh_insert(&engine->conns_tickable, conn, conn->cn_last_ticked);
733            engine_incref_conn(conn, LSCONN_TICKABLE);
734        }
735    }
736
737    process_connections(engine, conn_iter_next_tickable, now);
738    ENGINE_OUT(engine);
739}
740
741
742static int
743generate_header (const lsquic_packet_out_t *packet_out,
744                 const struct parse_funcs *pf, lsquic_cid_t cid,
745                 unsigned char *buf, size_t bufsz)
746{
747    return pf->pf_gen_reg_pkt_header(buf, bufsz,
748        packet_out->po_flags & PO_CONN_ID ? &cid                    : NULL,
749        packet_out->po_flags & PO_VERSION ? &packet_out->po_ver_tag : NULL,
750        packet_out->po_flags & PO_NONCE   ? packet_out->po_nonce    : NULL,
751        packet_out->po_packno, lsquic_packet_out_packno_bits(packet_out));
752}
753
754
755static ssize_t
756really_encrypt_packet (const lsquic_conn_t *conn,
757                       const lsquic_packet_out_t *packet_out,
758                       unsigned char *buf, size_t bufsz)
759{
760    int enc, header_sz, is_hello_packet;
761    size_t packet_sz;
762    unsigned char header_buf[QUIC_MAX_PUBHDR_SZ];
763
764    header_sz = generate_header(packet_out, conn->cn_pf, conn->cn_cid,
765                                            header_buf, sizeof(header_buf));
766    if (header_sz < 0)
767        return -1;
768
769    is_hello_packet = !!(packet_out->po_flags & PO_HELLO);
770    enc = conn->cn_esf->esf_encrypt(conn->cn_enc_session, conn->cn_version, 0,
771                packet_out->po_packno, header_buf, header_sz,
772                packet_out->po_data, packet_out->po_data_sz,
773                buf, bufsz, &packet_sz, is_hello_packet);
774    if (0 == enc)
775    {
776        LSQ_DEBUG("encrypted packet %"PRIu64"; plaintext is %u bytes, "
777            "ciphertext is %zd bytes",
778            packet_out->po_packno,
779            lsquic_po_header_length(packet_out->po_flags) +
780                                                packet_out->po_data_sz,
781            packet_sz);
782        return packet_sz;
783    }
784    else
785        return -1;
786}
787
788
789static enum { ENCPA_OK, ENCPA_NOMEM, ENCPA_BADCRYPT, }
790encrypt_packet (lsquic_engine_t *engine, const lsquic_conn_t *conn,
791                                            lsquic_packet_out_t *packet_out)
792{
793    ssize_t enc_sz;
794    size_t bufsz;
795    unsigned sent_sz;
796    unsigned char *buf;
797
798    bufsz = lsquic_po_header_length(packet_out->po_flags) +
799                                packet_out->po_data_sz + QUIC_PACKET_HASH_SZ;
800    buf = engine->pub.enp_pmi->pmi_allocate(engine->pub.enp_pmi_ctx, bufsz);
801    if (!buf)
802    {
803        LSQ_DEBUG("could not allocate memory for outgoing packet of size %zd",
804                                                                        bufsz);
805        return ENCPA_NOMEM;
806    }
807
808    {
809        enc_sz = really_encrypt_packet(conn, packet_out, buf, bufsz);
810        sent_sz = enc_sz;
811    }
812
813    if (enc_sz < 0)
814    {
815        engine->pub.enp_pmi->pmi_release(engine->pub.enp_pmi_ctx, buf);
816        return ENCPA_BADCRYPT;
817    }
818
819    packet_out->po_enc_data    = buf;
820    packet_out->po_enc_data_sz = enc_sz;
821    packet_out->po_sent_sz     = sent_sz;
822    packet_out->po_flags |= PO_ENCRYPTED|PO_SENT_SZ;
823
824    return ENCPA_OK;
825}
826
827
828STAILQ_HEAD(conns_stailq, lsquic_conn);
829TAILQ_HEAD(conns_tailq, lsquic_conn);
830
831
832struct conns_out_iter
833{
834    struct min_heap            *coi_heap;
835    TAILQ_HEAD(, lsquic_conn)   coi_active_list,
836                                coi_inactive_list;
837    lsquic_conn_t              *coi_next;
838#ifndef NDEBUG
839    lsquic_time_t               coi_last_sent;
840#endif
841};
842
843
844static void
845coi_init (struct conns_out_iter *iter, struct lsquic_engine *engine)
846{
847    iter->coi_heap = &engine->conns_out;
848    iter->coi_next = NULL;
849    TAILQ_INIT(&iter->coi_active_list);
850    TAILQ_INIT(&iter->coi_inactive_list);
851#ifndef NDEBUG
852    iter->coi_last_sent = 0;
853#endif
854}
855
856
857static lsquic_conn_t *
858coi_next (struct conns_out_iter *iter)
859{
860    lsquic_conn_t *conn;
861
862    if (lsquic_mh_count(iter->coi_heap) > 0)
863    {
864        conn = lsquic_mh_pop(iter->coi_heap);
865        TAILQ_INSERT_TAIL(&iter->coi_active_list, conn, cn_next_out);
866        conn->cn_flags |= LSCONN_COI_ACTIVE;
867#ifndef NDEBUG
868        if (iter->coi_last_sent)
869            assert(iter->coi_last_sent <= conn->cn_last_sent);
870        iter->coi_last_sent = conn->cn_last_sent;
871#endif
872        return conn;
873    }
874    else if (!TAILQ_EMPTY(&iter->coi_active_list))
875    {
876        conn = iter->coi_next;
877        if (!conn)
878            conn = TAILQ_FIRST(&iter->coi_active_list);
879        if (conn)
880            iter->coi_next = TAILQ_NEXT(conn, cn_next_out);
881        return conn;
882    }
883    else
884        return NULL;
885}
886
887
888static void
889coi_deactivate (struct conns_out_iter *iter, lsquic_conn_t *conn)
890{
891    if (!(conn->cn_flags & LSCONN_EVANESCENT))
892    {
893        assert(!TAILQ_EMPTY(&iter->coi_active_list));
894        TAILQ_REMOVE(&iter->coi_active_list, conn, cn_next_out);
895        conn->cn_flags &= ~LSCONN_COI_ACTIVE;
896        TAILQ_INSERT_TAIL(&iter->coi_inactive_list, conn, cn_next_out);
897        conn->cn_flags |= LSCONN_COI_INACTIVE;
898    }
899}
900
901
902static void
903coi_reactivate (struct conns_out_iter *iter, lsquic_conn_t *conn)
904{
905    assert(conn->cn_flags & LSCONN_COI_INACTIVE);
906    TAILQ_REMOVE(&iter->coi_inactive_list, conn, cn_next_out);
907    conn->cn_flags &= ~LSCONN_COI_INACTIVE;
908    TAILQ_INSERT_TAIL(&iter->coi_active_list, conn, cn_next_out);
909    conn->cn_flags |= LSCONN_COI_ACTIVE;
910}
911
912
913static void
914coi_reheap (struct conns_out_iter *iter, lsquic_engine_t *engine)
915{
916    lsquic_conn_t *conn;
917    while ((conn = TAILQ_FIRST(&iter->coi_active_list)))
918    {
919        TAILQ_REMOVE(&iter->coi_active_list, conn, cn_next_out);
920        conn->cn_flags &= ~LSCONN_COI_ACTIVE;
921        lsquic_mh_insert(iter->coi_heap, conn, conn->cn_last_sent);
922    }
923    while ((conn = TAILQ_FIRST(&iter->coi_inactive_list)))
924    {
925        TAILQ_REMOVE(&iter->coi_inactive_list, conn, cn_next_out);
926        conn->cn_flags &= ~LSCONN_COI_INACTIVE;
927        (void) engine_decref_conn(engine, conn, LSCONN_HAS_OUTGOING);
928    }
929}
930
931
932static unsigned
933send_batch (lsquic_engine_t *engine, struct conns_out_iter *conns_iter,
934                  struct out_batch *batch, unsigned n_to_send)
935{
936    int n_sent, i;
937    lsquic_time_t now;
938
939    /* Set sent time before the write to avoid underestimating RTT */
940    now = lsquic_time_now();
941    for (i = 0; i < (int) n_to_send; ++i)
942        batch->packets[i]->po_sent = now;
943    n_sent = engine->packets_out(engine->packets_out_ctx, batch->outs,
944                                                                n_to_send);
945    if (n_sent >= 0)
946        LSQ_DEBUG("packets out returned %d (out of %u)", n_sent, n_to_send);
947    else
948    {
949        engine->pub.enp_flags &= ~ENPUB_CAN_SEND;
950        LSQ_DEBUG("packets out returned an error: %s", strerror(errno));
951        EV_LOG_GENERIC_EVENT("cannot send packets");
952        n_sent = 0;
953    }
954    if (n_sent > 0)
955        engine->last_sent = now + n_sent;
956    for (i = 0; i < n_sent; ++i)
957    {
958        eng_hist_inc(&engine->history, now, sl_packets_out);
959        EV_LOG_PACKET_SENT(batch->conns[i]->cn_cid, batch->packets[i]);
960        batch->conns[i]->cn_if->ci_packet_sent(batch->conns[i],
961                                                    batch->packets[i]);
962        /* `i' is added to maintain relative order */
963        batch->conns[i]->cn_last_sent = now + i;
964        /* Release packet out buffer as soon as the packet is sent
965         * successfully.  If not successfully sent, we hold on to
966         * this buffer until the packet sending is attempted again
967         * or until it times out and regenerated.
968         */
969        if (batch->packets[i]->po_flags & PO_ENCRYPTED)
970        {
971            batch->packets[i]->po_flags &= ~PO_ENCRYPTED;
972            engine->pub.enp_pmi->pmi_release(engine->pub.enp_pmi_ctx,
973                                                batch->packets[i]->po_enc_data);
974            batch->packets[i]->po_enc_data = NULL;  /* JIC */
975        }
976    }
977    if (LSQ_LOG_ENABLED_EXT(LSQ_LOG_DEBUG, LSQLM_EVENT))
978        for ( ; i < (int) n_to_send; ++i)
979            EV_LOG_PACKET_NOT_SENT(batch->conns[i]->cn_cid, batch->packets[i]);
980    /* Return packets to the connection in reverse order so that the packet
981     * ordering is maintained.
982     */
983    for (i = (int) n_to_send - 1; i >= n_sent; --i)
984    {
985        batch->conns[i]->cn_if->ci_packet_not_sent(batch->conns[i],
986                                                    batch->packets[i]);
987        if (!(batch->conns[i]->cn_flags & (LSCONN_COI_ACTIVE|LSCONN_EVANESCENT)))
988            coi_reactivate(conns_iter, batch->conns[i]);
989    }
990    return n_sent;
991}
992
993
994/* Return 1 if went past deadline, 0 otherwise */
995static int
996check_deadline (lsquic_engine_t *engine)
997{
998    if (engine->pub.enp_settings.es_proc_time_thresh &&
999                                lsquic_time_now() > engine->deadline)
1000    {
1001        LSQ_INFO("went past threshold of %u usec, stop sending",
1002                            engine->pub.enp_settings.es_proc_time_thresh);
1003        engine->flags |= ENG_PAST_DEADLINE;
1004        return 1;
1005    }
1006    else
1007        return 0;
1008}
1009
1010
1011static void
1012send_packets_out (struct lsquic_engine *engine,
1013                  struct conns_tailq *ticked_conns,
1014                  struct conns_stailq *closed_conns)
1015{
1016    unsigned n, w, n_sent, n_batches_sent;
1017    lsquic_packet_out_t *packet_out;
1018    lsquic_conn_t *conn;
1019    struct out_batch *const batch = &engine->out_batch;
1020    struct conns_out_iter conns_iter;
1021    int shrink, deadline_exceeded;
1022
1023    coi_init(&conns_iter, engine);
1024    n_batches_sent = 0;
1025    n_sent = 0, n = 0;
1026    shrink = 0;
1027    deadline_exceeded = 0;
1028
1029    while ((conn = coi_next(&conns_iter)))
1030    {
1031        packet_out = conn->cn_if->ci_next_packet_to_send(conn);
1032        if (!packet_out) {
1033            LSQ_DEBUG("batched all outgoing packets for conn %"PRIu64,
1034                                                            conn->cn_cid);
1035            coi_deactivate(&conns_iter, conn);
1036            continue;
1037        }
1038        if (!(packet_out->po_flags & (PO_ENCRYPTED|PO_NOENCRYPT)))
1039        {
1040            switch (encrypt_packet(engine, conn, packet_out))
1041            {
1042            case ENCPA_NOMEM:
1043                /* Send what we have and wait for a more opportune moment */
1044                conn->cn_if->ci_packet_not_sent(conn, packet_out);
1045                goto end_for;
1046            case ENCPA_BADCRYPT:
1047                /* This is pretty bad: close connection immediately */
1048                conn->cn_if->ci_packet_not_sent(conn, packet_out);
1049                LSQ_INFO("conn %"PRIu64" has unsendable packets", conn->cn_cid);
1050                if (!(conn->cn_flags & LSCONN_EVANESCENT))
1051                {
1052                    if (!(conn->cn_flags & LSCONN_CLOSING))
1053                    {
1054                        STAILQ_INSERT_TAIL(closed_conns, conn, cn_next_closed_conn);
1055                        engine_incref_conn(conn, LSCONN_CLOSING);
1056                        if (conn->cn_flags & LSCONN_HASHED)
1057                            remove_conn_from_hash(engine, conn);
1058                    }
1059                    coi_deactivate(&conns_iter, conn);
1060                    if (conn->cn_flags & LSCONN_TICKED)
1061                    {
1062                        TAILQ_REMOVE(ticked_conns, conn, cn_next_ticked);
1063                        engine_decref_conn(engine, conn, LSCONN_TICKED);
1064                    }
1065                }
1066                continue;
1067            case ENCPA_OK:
1068                break;
1069            }
1070        }
1071        LSQ_DEBUG("batched packet %"PRIu64" for connection %"PRIu64,
1072                                        packet_out->po_packno, conn->cn_cid);
1073        assert(conn->cn_flags & LSCONN_HAS_PEER_SA);
1074        if (packet_out->po_flags & PO_ENCRYPTED)
1075        {
1076            batch->outs[n].buf     = packet_out->po_enc_data;
1077            batch->outs[n].sz      = packet_out->po_enc_data_sz;
1078        }
1079        else
1080        {
1081            batch->outs[n].buf     = packet_out->po_data;
1082            batch->outs[n].sz      = packet_out->po_data_sz;
1083        }
1084        batch->outs   [n].peer_ctx = conn->cn_peer_ctx;
1085        batch->outs   [n].local_sa = (struct sockaddr *) conn->cn_local_addr;
1086        batch->outs   [n].dest_sa  = (struct sockaddr *) conn->cn_peer_addr;
1087        batch->conns  [n]          = conn;
1088        batch->packets[n]          = packet_out;
1089        ++n;
1090        if (n == engine->batch_size)
1091        {
1092            n = 0;
1093            w = send_batch(engine, &conns_iter, batch, engine->batch_size);
1094            ++n_batches_sent;
1095            n_sent += w;
1096            if (w < engine->batch_size)
1097            {
1098                shrink = 1;
1099                break;
1100            }
1101            deadline_exceeded = check_deadline(engine);
1102            if (deadline_exceeded)
1103                break;
1104            grow_batch_size(engine);
1105        }
1106    }
1107  end_for:
1108
1109    if (n > 0) {
1110        w = send_batch(engine, &conns_iter, batch, n);
1111        n_sent += w;
1112        shrink = w < n;
1113        ++n_batches_sent;
1114        deadline_exceeded = check_deadline(engine);
1115    }
1116
1117    if (shrink)
1118        shrink_batch_size(engine);
1119    else if (n_batches_sent > 1 && !deadline_exceeded)
1120        grow_batch_size(engine);
1121
1122    coi_reheap(&conns_iter, engine);
1123
1124    LSQ_DEBUG("%s: sent %u packet%.*s", __func__, n_sent, n_sent != 1, "s");
1125}
1126
1127
1128int
1129lsquic_engine_has_unsent_packets (lsquic_engine_t *engine)
1130{
1131    return lsquic_mh_count(&engine->conns_out) > 0
1132    ;
1133}
1134
1135
1136static void
1137reset_deadline (lsquic_engine_t *engine, lsquic_time_t now)
1138{
1139    engine->deadline = now + engine->pub.enp_settings.es_proc_time_thresh;
1140    engine->flags &= ~ENG_PAST_DEADLINE;
1141}
1142
1143
1144/* TODO: this is a user-facing function, account for load */
1145void
1146lsquic_engine_send_unsent_packets (lsquic_engine_t *engine)
1147{
1148    lsquic_conn_t *conn;
1149    struct conns_stailq closed_conns;
1150    struct conns_tailq ticked_conns = TAILQ_HEAD_INITIALIZER(ticked_conns);
1151
1152    STAILQ_INIT(&closed_conns);
1153    reset_deadline(engine, lsquic_time_now());
1154    if (!(engine->pub.enp_flags & ENPUB_CAN_SEND))
1155    {
1156        LSQ_DEBUG("can send again");
1157        EV_LOG_GENERIC_EVENT("can send again");
1158        engine->pub.enp_flags |= ENPUB_CAN_SEND;
1159    }
1160
1161    send_packets_out(engine, &ticked_conns, &closed_conns);
1162
1163    while ((conn = STAILQ_FIRST(&closed_conns))) {
1164        STAILQ_REMOVE_HEAD(&closed_conns, cn_next_closed_conn);
1165        (void) engine_decref_conn(engine, conn, LSCONN_CLOSING);
1166    }
1167
1168}
1169
1170
1171static void
1172process_connections (lsquic_engine_t *engine, conn_iter_f next_conn,
1173                     lsquic_time_t now)
1174{
1175    lsquic_conn_t *conn;
1176    enum tick_st tick_st;
1177    unsigned i;
1178    lsquic_time_t next_tick_time;
1179    struct conns_stailq closed_conns;
1180    struct conns_tailq ticked_conns;
1181
1182    eng_hist_tick(&engine->history, now);
1183
1184    STAILQ_INIT(&closed_conns);
1185    TAILQ_INIT(&ticked_conns);
1186    reset_deadline(engine, now);
1187
1188    i = 0;
1189    while ((conn = next_conn(engine))
1190          )
1191    {
1192        tick_st = conn->cn_if->ci_tick(conn, now);
1193        conn->cn_last_ticked = now + i /* Maintain relative order */ ++;
1194        if (tick_st & TICK_SEND)
1195        {
1196            if (!(conn->cn_flags & LSCONN_HAS_OUTGOING))
1197            {
1198                lsquic_mh_insert(&engine->conns_out, conn, conn->cn_last_sent);
1199                engine_incref_conn(conn, LSCONN_HAS_OUTGOING);
1200            }
1201        }
1202        if (tick_st & TICK_CLOSE)
1203        {
1204            STAILQ_INSERT_TAIL(&closed_conns, conn, cn_next_closed_conn);
1205            engine_incref_conn(conn, LSCONN_CLOSING);
1206            if (conn->cn_flags & LSCONN_HASHED)
1207                remove_conn_from_hash(engine, conn);
1208        }
1209        else
1210        {
1211            TAILQ_INSERT_TAIL(&ticked_conns, conn, cn_next_ticked);
1212            engine_incref_conn(conn, LSCONN_TICKED);
1213        }
1214    }
1215
1216    if ((engine->pub.enp_flags & ENPUB_CAN_SEND)
1217                        && lsquic_engine_has_unsent_packets(engine))
1218        send_packets_out(engine, &ticked_conns, &closed_conns);
1219
1220    while ((conn = STAILQ_FIRST(&closed_conns))) {
1221        STAILQ_REMOVE_HEAD(&closed_conns, cn_next_closed_conn);
1222        (void) engine_decref_conn(engine, conn, LSCONN_CLOSING);
1223    }
1224
1225    /* TODO Heapification can be optimized by switching to the Floyd method:
1226     * https://en.wikipedia.org/wiki/Binary_heap#Building_a_heap
1227     */
1228    while ((conn = TAILQ_FIRST(&ticked_conns)))
1229    {
1230        TAILQ_REMOVE(&ticked_conns, conn, cn_next_ticked);
1231        engine_decref_conn(engine, conn, LSCONN_TICKED);
1232        if (!(conn->cn_flags & LSCONN_TICKABLE)
1233            && conn->cn_if->ci_is_tickable(conn))
1234        {
1235            lsquic_mh_insert(&engine->conns_tickable, conn, conn->cn_last_ticked);
1236            engine_incref_conn(conn, LSCONN_TICKABLE);
1237        }
1238        else if (!(conn->cn_flags & LSCONN_ATTQ))
1239        {
1240            next_tick_time = conn->cn_if->ci_next_tick_time(conn);
1241            if (next_tick_time)
1242            {
1243                if (0 == attq_add(engine->attq, conn, next_tick_time))
1244                    engine_incref_conn(conn, LSCONN_ATTQ);
1245            }
1246            else
1247                assert(0);
1248        }
1249    }
1250
1251}
1252
1253
1254/* Return 0 if packet is being processed by a real connection, 1 if the
1255 * packet was processed, but not by a connection, and -1 on error.
1256 */
1257int
1258lsquic_engine_packet_in (lsquic_engine_t *engine,
1259    const unsigned char *packet_in_data, size_t packet_in_size,
1260    const struct sockaddr *sa_local, const struct sockaddr *sa_peer,
1261    void *peer_ctx)
1262{
1263    struct packin_parse_state ppstate;
1264    lsquic_packet_in_t *packet_in;
1265
1266    if (packet_in_size > QUIC_MAX_PACKET_SZ)
1267    {
1268        LSQ_DEBUG("Cannot handle packet_in_size(%zd) > %d packet incoming "
1269            "packet's header", packet_in_size, QUIC_MAX_PACKET_SZ);
1270        errno = E2BIG;
1271        return -1;
1272    }
1273
1274    packet_in = lsquic_mm_get_packet_in(&engine->pub.enp_mm);
1275    if (!packet_in)
1276        return -1;
1277
1278    /* Library does not modify packet_in_data, it is not referenced after
1279     * this function returns and subsequent release of pi_data is guarded
1280     * by PI_OWN_DATA flag.
1281     */
1282    packet_in->pi_data = (unsigned char *) packet_in_data;
1283    if (0 != parse_packet_in_begin(packet_in, packet_in_size,
1284                                        engine->flags & ENG_SERVER, &ppstate))
1285    {
1286        LSQ_DEBUG("Cannot parse incoming packet's header");
1287        lsquic_mm_put_packet_in(&engine->pub.enp_mm, packet_in);
1288        errno = EINVAL;
1289        return -1;
1290    }
1291
1292    packet_in->pi_received = lsquic_time_now();
1293    eng_hist_inc(&engine->history, packet_in->pi_received, sl_packets_in);
1294    return process_packet_in(engine, packet_in, &ppstate, sa_local, sa_peer,
1295                                                                    peer_ctx);
1296}
1297
1298
1299#if __GNUC__ && !defined(NDEBUG)
1300__attribute__((weak))
1301#endif
1302unsigned
1303lsquic_engine_quic_versions (const lsquic_engine_t *engine)
1304{
1305    return engine->pub.enp_settings.es_versions;
1306}
1307
1308
1309int
1310lsquic_engine_earliest_adv_tick (lsquic_engine_t *engine, int *diff)
1311{
1312    const lsquic_time_t *next_time;
1313    lsquic_time_t now;
1314
1315    if (((engine->flags & ENG_PAST_DEADLINE)
1316                                    && lsquic_mh_count(&engine->conns_out))
1317        || lsquic_mh_count(&engine->conns_tickable))
1318    {
1319        *diff = 0;
1320        return 1;
1321    }
1322
1323    next_time = attq_next_time(engine->attq);
1324    if (!next_time)
1325        return 0;
1326
1327    now = lsquic_time_now();
1328    *diff = (int) ((int64_t) *next_time - (int64_t) now);
1329    return 1;
1330}
1331
1332
1333unsigned
1334lsquic_engine_count_attq (lsquic_engine_t *engine, int from_now)
1335{
1336    lsquic_time_t now;
1337    now = lsquic_time_now();
1338    if (from_now < 0)
1339        now -= from_now;
1340    else
1341        now += from_now;
1342    return attq_count_before(engine->attq, now);
1343}
1344