summaryrefslogtreecommitdiff
path: root/src/ipcpd/unicast/fa.c
blob: 2591a162872cc4e50a1a2207e8539f52684e7b00 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
/*
 * Ouroboros - Copyright (C) 2016 - 2023
 *
 * Flow allocator of the IPC Process
 *
 *    Dimitri Staessens <dimitri@ouroboros.rocks>
 *    Sander Vrijders   <sander@ouroboros.rocks>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., http://www.fsf.org/about/contact/.
 */

#if defined(__linux__) || defined(__CYGWIN__)
#define _DEFAULT_SOURCE
#else
#define _POSIX_C_SOURCE 200112L
#endif

#include "config.h"

#define FA               "flow-allocator"
#define OUROBOROS_PREFIX FA

#include <ouroboros/endian.h>
#include <ouroboros/logs.h>
#include <ouroboros/fqueue.h>
#include <ouroboros/errno.h>
#include <ouroboros/dev.h>
#include <ouroboros/ipcp-dev.h>
#include <ouroboros/rib.h>
#include <ouroboros/random.h>
#include <ouroboros/pthread.h>

#include "dir.h"
#include "fa.h"
#include "psched.h"
#include "ipcp.h"
#include "dt.h"
#include "ca.h"

#include <inttypes.h>
#include <stdlib.h>
#include <string.h>

#if defined (IPCP_FLOW_STATS) && !defined(CLOCK_REALTIME_COARSE)
#define CLOCK_REALTIME_COARSE CLOCK_REALTIME
#endif

#define TIMEOUT 10000 /* nanoseconds */

#define FLOW_REQ    0
#define FLOW_REPLY  1
#define FLOW_UPDATE 2
#define MSGBUFSZ    2048

#define STAT_FILE_LEN 0

struct fa_msg {
        uint64_t s_addr;
        uint64_t r_eid;
        uint64_t s_eid;
        uint8_t  code;
        int8_t   response;
        uint16_t ece;
        /* QoS parameters from spec, aligned */
        uint32_t delay;
        uint64_t bandwidth;
        uint32_t loss;
        uint32_t ber;
        uint32_t max_gap;
        uint32_t timeout;
        uint16_t cypher_s;
        uint8_t  availability;
        uint8_t  in_order;
} __attribute__((packed));

struct cmd {
        struct list_head     next;
        struct shm_du_buff * sdb;
};

struct fa_flow {
#ifdef IPCP_FLOW_STATS
        time_t   stamp;    /* Flow creation                  */
        size_t   p_snd;    /* Packets sent                   */
        size_t   p_snd_f;  /* Packets sent fail              */
        size_t   b_snd;    /* Bytes sent                     */
        size_t   b_snd_f;  /* Bytes sent fail                */
        size_t   p_rcv;    /* Packets received               */
        size_t   p_rcv_f;  /* Packets received fail          */
        size_t   b_rcv;    /* Bytes received                 */
        size_t   b_rcv_f;  /* Bytes received fail            */
        size_t   u_snd;    /* Flow updates sent              */
        size_t   u_rcv;    /* Flow updates received          */
#endif
        uint64_t s_eid;  /* Local endpoint id                */
        uint64_t r_eid;  /* Remote endpoint id               */
        uint64_t r_addr; /* Remote address                   */
        void *   ctx;    /* Congestion avoidance context     */
};

struct {
        pthread_rwlock_t flows_lock;
        struct fa_flow   flows[PROG_MAX_FLOWS];
#ifdef IPCP_FLOW_STATS
        size_t           n_flows;
#endif
        uint32_t         eid;

        struct list_head cmds;
        pthread_cond_t   cond;
        pthread_mutex_t  mtx;
        pthread_t        worker;

        struct psched *  psched;
} fa;

static int fa_rib_read(const char * path,
                       char *       buf,
                       size_t       len)
{
#ifdef IPCP_FLOW_STATS
        struct fa_flow * flow;
        int              fd;
        char             r_addrstr[21];
        char             s_eidstr[21];
        char             r_eidstr[21];
        char             tmstr[20];
        char             castr[1024];
        char *           entry;
        struct tm *      tm;

        entry = strstr(path, RIB_SEPARATOR) + 1;
        assert(entry);

        fd = atoi(entry);

        if (fd < 0 || fd >= PROG_MAX_FLOWS)
                return -1;

        if (len < 1536)
                return 0;

        flow = &fa.flows[fd];

        buf[0] = '\0';

        pthread_rwlock_rdlock(&fa.flows_lock);

        if (flow->stamp ==0) {
                pthread_rwlock_unlock(&fa.flows_lock);
                return 0;
        }

        sprintf(r_addrstr, "%" PRIu64, flow->r_addr);
        sprintf(s_eidstr, "%" PRIu64, flow->s_eid);
        sprintf(r_eidstr, "%" PRIu64, flow->r_eid);

        tm = localtime(&flow->stamp);
        strftime(tmstr, sizeof(tmstr), "%F %T", tm);

        ca_print_stats(flow->ctx, castr, 1024);

        sprintf(buf,
                "Flow established at:             %20s\n"
                "Remote address:                  %20s\n"
                "Local endpoint ID:               %20s\n"
                "Remote endpoint ID:              %20s\n"
                "Sent (packets):                  %20zu\n"
                "Sent (bytes):                    %20zu\n"
                "Send failed (packets):           %20zu\n"
                "Send failed (bytes):             %20zu\n"
                "Received (packets):              %20zu\n"
                "Received (bytes):                %20zu\n"
                "Receive failed (packets):        %20zu\n"
                "Receive failed (bytes):          %20zu\n"
                "Sent flow updates (packets):     %20zu\n"
                "Received flow updates (packets): %20zu\n"
                "%s",
                tmstr, r_addrstr,
                s_eidstr, r_eidstr,
                flow->p_snd, flow->b_snd,
                flow->p_snd_f, flow->b_snd_f,
                flow->p_rcv, flow->b_rcv,
                flow->b_rcv_f, flow->b_rcv_f,
                flow->u_snd, flow->u_rcv,
                castr);

        pthread_rwlock_unlock(&fa.flows_lock);

        return strlen(buf);
#else
        (void) path;
        (void) buf;
        (void) len;
        return 0;
#endif
}

static int fa_rib_readdir(char *** buf)
{
#ifdef IPCP_FLOW_STATS
        char   entry[RIB_PATH_LEN + 1];
        size_t i;
        int    idx = 0;

        pthread_rwlock_rdlock(&fa.flows_lock);

        if (fa.n_flows < 1) {
                pthread_rwlock_unlock(&fa.flows_lock);
                return 0;
        }

        *buf = malloc(sizeof(**buf) * fa.n_flows);
        if (*buf == NULL) {
                pthread_rwlock_unlock(&fa.flows_lock);
                return -ENOMEM;
        }

        for (i = 0; i < PROG_MAX_FLOWS; ++i) {
                struct fa_flow * flow;

                flow = &fa.flows[i];
                if (flow->stamp == 0)
                        continue;

                sprintf(entry, "%zu", i);

                (*buf)[idx] = malloc(strlen(entry) + 1);
                if ((*buf)[idx] == NULL) {
                        while (idx-- > 0)
                                free((*buf)[idx]);
                        free(*buf);
                        pthread_rwlock_unlock(&fa.flows_lock);
                        return -ENOMEM;
                }

                strcpy((*buf)[idx++], entry);
        }

        assert((size_t) idx == fa.n_flows);

        pthread_rwlock_unlock(&fa.flows_lock);

        return idx;
#else
        (void) buf;
        return 0;
#endif
}

static int fa_rib_getattr(const char *      path,
                          struct rib_attr * attr)
{
#ifdef IPCP_FLOW_STATS
        int              fd;
        char *           entry;
        struct fa_flow * flow;

        entry = strstr(path, RIB_SEPARATOR) + 1;
        assert(entry);

        fd = atoi(entry);

        flow = &fa.flows[fd];

        pthread_rwlock_rdlock(&fa.flows_lock);

        if (flow->stamp != 0) {
                attr->size  = 1536;
                attr->mtime = flow->stamp;
        } else {
                attr->size  = 0;
                attr->mtime = 0;
        }

        pthread_rwlock_unlock(&fa.flows_lock);
#else
        (void) path;
        (void) attr;
#endif
        return 0;
}

static struct rib_ops r_ops = {
        .read    = fa_rib_read,
        .readdir = fa_rib_readdir,
        .getattr = fa_rib_getattr
};

static int eid_to_fd(uint64_t eid)
{
        struct fa_flow * flow;
        int              fd;

        fd = eid & 0xFFFFFFFF;

        if (fd < 0 || fd >= PROG_MAX_FLOWS)
                return -1;

        flow = &fa.flows[fd];

        if (flow->s_eid == eid)
                return fd;

        return -1;
}

static uint64_t gen_eid(int fd)
{
        uint32_t rnd;

        if (random_buffer(&rnd, sizeof(rnd)) < 0)
                return fa.eid; /* INVALID */

        fd &= 0xFFFFFFFF;

        return ((uint64_t) rnd << 32) + fd;
}

static void packet_handler(int                  fd,
                           qoscube_t            qc,
                           struct shm_du_buff * sdb)
{
        struct fa_flow * flow;
        uint64_t         r_addr;
        uint64_t         r_eid;
        ca_wnd_t         wnd;
        size_t           len;

        flow = &fa.flows[fd];

        pthread_rwlock_wrlock(&fa.flows_lock);

        len = shm_du_buff_len(sdb);

#ifdef IPCP_FLOW_STATS
        ++flow->p_snd;
        flow->b_snd += len;
#endif
        wnd = ca_ctx_update_snd(flow->ctx, len);

        r_addr = flow->r_addr;
        r_eid  = flow->r_eid;

        pthread_rwlock_unlock(&fa.flows_lock);

        ca_wnd_wait(wnd);

        if (dt_write_packet(r_addr, qc, r_eid, sdb)) {
                ipcp_sdb_release(sdb);
                log_warn("Failed to forward packet.");
#ifdef IPCP_FLOW_STATS
                pthread_rwlock_wrlock(&fa.flows_lock);
                ++flow->p_snd_f;
                flow->b_snd_f += len;
                pthread_rwlock_unlock(&fa.flows_lock);
#endif
                return;
        }
}

static int fa_flow_init(struct fa_flow * flow)
{
#ifdef IPCP_FLOW_STATS
        struct timespec now;
#endif
        memset(flow, 0, sizeof(*flow));

        flow->r_eid  = -1;
        flow->s_eid  = -1;
        flow->r_addr = INVALID_ADDR;

        flow->ctx = ca_ctx_create();
        if (flow->ctx == NULL)
                return -1;

#ifdef IPCP_FLOW_STATS
        clock_gettime(CLOCK_REALTIME_COARSE, &now);

        flow->stamp = now.tv_sec;

        ++fa.n_flows;
#endif
        return 0;
}

static void fa_flow_fini(struct fa_flow * flow)
{
        ca_ctx_destroy(flow->ctx);

        memset(flow, 0, sizeof(*flow));

        flow->r_eid  = -1;
        flow->s_eid  = -1;
        flow->r_addr = INVALID_ADDR;

#ifdef IPCP_FLOW_STATS
        --fa.n_flows;
#endif
}

static void fa_post_packet(void *               comp,
                           struct shm_du_buff * sdb)
{
        struct cmd * cmd;

        assert(comp == &fa);

        (void) comp;

        cmd = malloc(sizeof(*cmd));
        if (cmd == NULL) {
                log_err("Command failed. Out of memory.");
                ipcp_sdb_release(sdb);
                return;
        }

        cmd->sdb = sdb;

        pthread_mutex_lock(&fa.mtx);

        list_add(&cmd->next, &fa.cmds);

        pthread_cond_signal(&fa.cond);

        pthread_mutex_unlock(&fa.mtx);
}

static size_t fa_wait_for_fa_msg(struct fa_msg * msg)
{
        struct cmd * cmd;
        size_t       len;

        pthread_mutex_lock(&fa.mtx);

        pthread_cleanup_push(__cleanup_mutex_unlock, &fa.mtx);

        while (list_is_empty(&fa.cmds))
                pthread_cond_wait(&fa.cond, &fa.mtx);

        cmd = list_last_entry(&fa.cmds, struct cmd, next);
        list_del(&cmd->next);

        pthread_cleanup_pop(true);

        len = shm_du_buff_len(cmd->sdb);
        if (len > MSGBUFSZ || len < sizeof(*msg)) {
                log_warn("Invalid flow allocation message (len: %zd)\n", len);
                free(cmd);
                return 0; /* No valid message */
        }

        memcpy(msg, shm_du_buff_head(cmd->sdb), len);

        ipcp_sdb_release(cmd->sdb);

        free(cmd);

        return len;
}

static int fa_wait_irmd_alloc(uint8_t *    dst,
                              qosspec_t    qs,
                              const void * data,
                              size_t       len)
{
        struct timespec ts  = {0, TIMEOUT * 1000};
        struct timespec abstime;
        int             fd;
        time_t          mpl = IPCP_UNICAST_MPL;

        clock_gettime(PTHREAD_COND_CLOCK, &abstime);

        pthread_mutex_lock(&ipcpi.alloc_lock);

        while (ipcpi.alloc_id != -1 && ipcp_get_state() == IPCP_OPERATIONAL) {
                ts_add(&abstime, &ts, &abstime);
                pthread_cond_timedwait(&ipcpi.alloc_cond,
                                       &ipcpi.alloc_lock,
                                       &abstime);
        }

        if (ipcp_get_state() != IPCP_OPERATIONAL) {
                pthread_mutex_unlock(&ipcpi.alloc_lock);
                log_dbg("Won't allocate over non-operational IPCP.");
                return -EIPCPSTATE;
        }

        assert(ipcpi.alloc_id == -1);

        fd = ipcp_flow_req_arr(dst, ipcp_dir_hash_len(), qs, mpl, data, len);
        if (fd < 0) {
                pthread_mutex_unlock(&ipcpi.alloc_lock);
                log_dbg("Failed to get fd for flow.");
                return -ENOTALLOC;
        }

        ipcpi.alloc_id = fd;
        pthread_cond_broadcast(&ipcpi.alloc_cond);

        pthread_mutex_unlock(&ipcpi.alloc_lock);

        return fd;
}

static int fa_wait_irmd_alloc_resp(int fd)
{
        struct timespec      ts = {0, TIMEOUT * 1000};
        struct timespec      abstime;

        clock_gettime(PTHREAD_COND_CLOCK, &abstime);

        pthread_mutex_lock(&ipcpi.alloc_lock);

        while (ipcpi.alloc_id != fd && ipcp_get_state() == IPCP_OPERATIONAL) {
                ts_add(&abstime, &ts, &abstime);
                pthread_cond_timedwait(&ipcpi.alloc_cond,
                                       &ipcpi.alloc_lock,
                                       &abstime);
        }

        if (ipcp_get_state() != IPCP_OPERATIONAL) {
                pthread_mutex_unlock(&ipcpi.alloc_lock);
                return -1;
        }

        assert(ipcpi.alloc_id == fd);

        ipcpi.alloc_id = -1;
        pthread_cond_broadcast(&ipcpi.alloc_cond);

        pthread_mutex_unlock(&ipcpi.alloc_lock);

        return 0;
}

static int fa_handle_flow_req(struct fa_msg * msg,
                              size_t          len)
{
        size_t           msg_len;
        int              fd;
        qosspec_t        qs;
        struct fa_flow * flow;
        uint8_t *        data;  /* Piggbacked data on flow alloc request. */
        size_t           dlen;  /* Length of piggybacked data.            */

        msg_len = sizeof(*msg) + ipcp_dir_hash_len();
        if (len < msg_len) {
                log_err("Invalid flow allocation request");
                return -EPERM;
        }

        data = (uint8_t *) msg + msg_len;
        dlen = len - msg_len;

        qs.delay        = ntoh32(msg->delay);
        qs.bandwidth    = ntoh64(msg->bandwidth);
        qs.availability = msg->availability;
        qs.loss         = ntoh32(msg->loss);
        qs.ber          = ntoh32(msg->ber);
        qs.in_order     = msg->in_order;
        qs.max_gap      = ntoh32(msg->max_gap);
        qs.cypher_s     = ntoh16(msg->cypher_s);
        qs.timeout      = ntoh32(msg->timeout);

        fd = fa_wait_irmd_alloc((uint8_t *) (msg + 1), qs, data, dlen);
        if (fd < 0)
                return fd;

        flow = &fa.flows[fd];

        pthread_rwlock_wrlock(&fa.flows_lock);

        fa_flow_init(flow);

        flow->s_eid  = gen_eid(fd);
        flow->r_eid  = ntoh64(msg->s_eid);
        flow->r_addr = ntoh64(msg->s_addr);

        pthread_rwlock_unlock(&fa.flows_lock);

        return fd;
}

static int fa_handle_flow_reply(struct fa_msg * msg,
                                size_t          len)
{
        int              fd;
        struct fa_flow * flow;
        uint8_t *        data;  /* Piggbacked data on flow alloc request. */
        size_t           dlen;  /* Length of piggybacked data.            */
        time_t           mpl = IPCP_UNICAST_MPL;

        assert(len >= sizeof(*msg));

        data = (uint8_t *) msg + sizeof(*msg);
        dlen = len - sizeof(*msg);

        pthread_rwlock_wrlock(&fa.flows_lock);

        fd = eid_to_fd(ntoh64(msg->r_eid));
        if (fd < 0) {
                pthread_rwlock_unlock(&fa.flows_lock);
                return -ENOTALLOC;
        }

        flow = &fa.flows[fd];

        flow->r_eid = ntoh64(msg->s_eid);

        if (msg->response < 0)
                fa_flow_fini(flow);
        else
                psched_add(fa.psched, fd);

        pthread_rwlock_unlock(&fa.flows_lock);

        if (ipcp_flow_alloc_reply(fd, msg->response, mpl, data, dlen))
                return -EIRMD;

        return 0;
}

static int fa_handle_flow_update(struct fa_msg * msg,
                                 size_t          len)
{
        struct fa_flow * flow;
        int              fd;

        (void) len;
        assert(len >= sizeof(*msg));

        pthread_rwlock_wrlock(&fa.flows_lock);

        fd = eid_to_fd(ntoh64(msg->r_eid));
        if (fd < 0) {
                pthread_rwlock_unlock(&fa.flows_lock);
                return -EPERM;
        }

        flow = &fa.flows[fd];
#ifdef IPCP_FLOW_STATS
        flow->u_rcv++;
#endif
        ca_ctx_update_ece(flow->ctx, ntoh16(msg->ece));

        pthread_rwlock_unlock(&fa.flows_lock);

        return 0;
}

static void * fa_handle_packet(void * o)
{
        (void) o;

        while (true) {
                uint8_t          buf[MSGBUFSZ];
                struct fa_msg *  msg;
                size_t           len;

                msg = (struct fa_msg *) buf;

                len = fa_wait_for_fa_msg(msg);
                if (len == 0)
                        continue;

                switch (msg->code) {
                case FLOW_REQ:
                        if (fa_handle_flow_req(msg, len) < 0)
                                log_err("Error handling flow alloc request.");
                        break;
                case FLOW_REPLY:
                        if (fa_handle_flow_reply(msg, len) < 0)
                                log_err("Error handling flow reply.");
                        break;
                case FLOW_UPDATE:
                        if (fa_handle_flow_update(msg, len) < 0)
                                log_err("Error handling flow update.");
                        break;
                default:
                        log_warn("Recieved unknown flow allocation message.");
                        break;
                }
        }

        return (void *) 0;
}

int fa_init(void)
{
        pthread_condattr_t cattr;

        if (pthread_rwlock_init(&fa.flows_lock, NULL))
                goto fail_rwlock;

        if (pthread_mutex_init(&fa.mtx, NULL))
                goto fail_mtx;

        if (pthread_condattr_init(&cattr))
                goto fail_cattr;

#ifndef __APPLE__
        pthread_condattr_setclock(&cattr, PTHREAD_COND_CLOCK);
#endif
        if (pthread_cond_init(&fa.cond, &cattr))
                goto fail_cond;

        pthread_condattr_destroy(&cattr);

        list_head_init(&fa.cmds);

        if (rib_reg(FA, &r_ops))
                goto fail_rib_reg;

        fa.eid = dt_reg_comp(&fa, &fa_post_packet, FA);
        if ((int) fa.eid < 0)
                goto fail_rib_reg;

        return 0;

 fail_rib_reg:
        pthread_cond_destroy(&fa.cond);
 fail_cond:
        pthread_condattr_destroy(&cattr);
 fail_cattr:
        pthread_mutex_destroy(&fa.mtx);
 fail_mtx:
        pthread_rwlock_destroy(&fa.flows_lock);
 fail_rwlock:
        log_err("Failed to initialize flow allocator.");
        return -1;
}

void fa_fini(void)
{
        rib_unreg(FA);

        pthread_cond_destroy(&fa.cond);;
        pthread_mutex_destroy(&fa.mtx);
        pthread_rwlock_destroy(&fa.flows_lock);
}

int fa_start(void)
{
        struct sched_param  par;
        int                 pol;
        int                 max;

        fa.psched = psched_create(packet_handler, np1_flow_read);
        if (fa.psched == NULL) {
                log_err("Failed to start packet scheduler.");
                goto fail_psched;
        }

        if (pthread_create(&fa.worker, NULL, fa_handle_packet, NULL)) {
                log_err("Failed to create worker thread.");
                goto fail_thread;
        }

        if (pthread_getschedparam(fa.worker, &pol, &par)) {
                log_err("Failed to get worker thread scheduling parameters.");
                goto fail_sched;
        }

        max = sched_get_priority_max(pol);
        if (max < 0) {
                log_err("Failed to get max priority for scheduler.");
                goto fail_sched;
        }

        par.sched_priority = max;

        if (pthread_setschedparam(fa.worker, pol, &par)) {
                log_err("Failed to set scheduler priority to maximum.");
                goto fail_sched;
        }

        return 0;

 fail_sched:
        pthread_cancel(fa.worker);
        pthread_join(fa.worker, NULL);
 fail_thread:
        psched_destroy(fa.psched);
 fail_psched:
        log_err("Failed to start flow allocator.");
        return -1;
}

void fa_stop(void)
{
        pthread_cancel(fa.worker);
        pthread_join(fa.worker, NULL);

        psched_destroy(fa.psched);
}

int fa_alloc(int             fd,
             const uint8_t * dst,
             qosspec_t       qs,
             const void *    data,
             size_t          dlen)
{
        struct fa_msg *      msg;
        struct shm_du_buff * sdb;
        struct fa_flow *     flow;
        uint64_t             addr;
        qoscube_t            qc = QOS_CUBE_BE;
        size_t               len;
        uint64_t             eid;

        addr = dir_query(dst);
        if (addr == 0)
                return -1;

        len = sizeof(*msg) + ipcp_dir_hash_len();

        if (ipcp_sdb_reserve(&sdb, len + dlen))
                return -1;

        msg = (struct fa_msg *) shm_du_buff_head(sdb);
        memset(msg, 0, sizeof(*msg));

        eid = gen_eid(fd);

        msg->code         = FLOW_REQ;
        msg->s_eid        = hton64(eid);
        msg->s_addr       = hton64(ipcpi.dt_addr);
        msg->delay        = hton32(qs.delay);
        msg->bandwidth    = hton64(qs.bandwidth);
        msg->availability = qs.availability;
        msg->loss         = hton32(qs.loss);
        msg->ber          = hton32(qs.ber);
        msg->in_order     = qs.in_order;
        msg->max_gap      = hton32(qs.max_gap);
        msg->cypher_s     = hton16(qs.cypher_s);
        msg->timeout      = hton32(qs.timeout);

        memcpy(msg + 1, dst, ipcp_dir_hash_len());
        if (dlen > 0)
                memcpy(shm_du_buff_head(sdb) + len, data, dlen);

        if (dt_write_packet(addr, qc, fa.eid, sdb)) {
                ipcp_sdb_release(sdb);
                return -1;
        }

        flow = &fa.flows[fd];

        pthread_rwlock_wrlock(&fa.flows_lock);

        fa_flow_init(flow);
        flow->r_addr = addr;
        flow->s_eid  = eid;

        pthread_rwlock_unlock(&fa.flows_lock);

        return 0;
}

int fa_alloc_resp(int          fd,
                  int          response,
                  const void * data,
                  size_t       len)
{
        struct fa_msg *      msg;
        struct shm_du_buff * sdb;
        struct fa_flow *     flow;
        qoscube_t            qc = QOS_CUBE_BE;

        flow = &fa.flows[fd];

        if (fa_wait_irmd_alloc_resp(fd) < 0)
                return -1;

        if (ipcp_sdb_reserve(&sdb, sizeof(*msg) + len)) {
                fa_flow_fini(flow);
                return -1;
        }

        msg = (struct fa_msg *) shm_du_buff_head(sdb);
        memset(msg, 0, sizeof(*msg));

        pthread_rwlock_wrlock(&fa.flows_lock);

        msg->code     = FLOW_REPLY;
        msg->r_eid    = hton64(flow->r_eid);
        msg->s_eid    = hton64(flow->s_eid);
        msg->response = response;

        if (len > 0)
                memcpy(msg + 1, data, len);

        if (response < 0) {
                fa_flow_fini(flow);
                ipcp_sdb_release(sdb);
        } else {
                psched_add(fa.psched, fd);
        }

        if (dt_write_packet(flow->r_addr, qc, fa.eid, sdb)) {
                fa_flow_fini(flow);
                pthread_rwlock_unlock(&fa.flows_lock);
                ipcp_sdb_release(sdb);
                return -1;
        }

        pthread_rwlock_unlock(&fa.flows_lock);

        return 0;
}

int fa_dealloc(int fd)
{
        if (ipcp_flow_fini(fd) < 0)
                return 0;

        psched_del(fa.psched, fd);

        pthread_rwlock_wrlock(&fa.flows_lock);

        fa_flow_fini(&fa.flows[fd]);

        pthread_rwlock_unlock(&fa.flows_lock);

        flow_dealloc(fd);

        return 0;
}

static int fa_update_remote(int      fd,
                            uint16_t ece)
{
        struct fa_msg *      msg;
        struct shm_du_buff * sdb;
        qoscube_t            qc = QOS_CUBE_BE;
        struct fa_flow *     flow;
        uint64_t             r_addr;

        if (ipcp_sdb_reserve(&sdb, sizeof(*msg))) {
                return -1;
        }

        msg = (struct fa_msg *) shm_du_buff_head(sdb);

        memset(msg, 0, sizeof(*msg));

        flow = &fa.flows[fd];

        pthread_rwlock_wrlock(&fa.flows_lock);

        msg->code  = FLOW_UPDATE;
        msg->r_eid = hton64(flow->r_eid);
        msg->ece   = hton16(ece);

        r_addr = flow->r_addr;
#ifdef IPCP_FLOW_STATS
        flow->u_snd++;
#endif
        pthread_rwlock_unlock(&fa.flows_lock);


        if (dt_write_packet(r_addr, qc, fa.eid, sdb)) {
                ipcp_sdb_release(sdb);
                return -1;
        }

        return 0;
}

void  fa_np1_rcv(uint64_t             eid,
                 uint8_t              ecn,
                 struct shm_du_buff * sdb)
{
        struct fa_flow * flow;
        bool             update;
        uint16_t         ece;
        int              fd;
        size_t           len;

        len = shm_du_buff_len(sdb);

        pthread_rwlock_wrlock(&fa.flows_lock);

        fd = eid_to_fd(eid);
        if (fd < 0) {
                pthread_rwlock_unlock(&fa.flows_lock);
                ipcp_sdb_release(sdb);
                return;
        }

        flow = &fa.flows[fd];

#ifdef IPCP_FLOW_STATS
        ++flow->p_rcv;
        flow->b_rcv += len;
#endif
        update = ca_ctx_update_rcv(flow->ctx, len, ecn, &ece);

        pthread_rwlock_unlock(&fa.flows_lock);

        if (ipcp_flow_write(fd, sdb) < 0) {
                ipcp_sdb_release(sdb);
#ifdef IPCP_FLOW_STATS
                pthread_rwlock_wrlock(&fa.flows_lock);
                ++flow->p_rcv_f;
                flow->b_rcv_f += len;
                pthread_rwlock_unlock(&fa.flows_lock);
#endif
        }

        if (update)
                fa_update_remote(eid, ece);
}