The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_car.c

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    1 /*-
    2  * Copyright (c) 2005 Nuno Antunes <nuno.antunes@gmail.com>
    3  * Copyright (c) 2007 Alexander Motin <mav@freebsd.org>
    4  * All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   18  * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
   19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   25  * SUCH DAMAGE.
   26  *
   27  * $FreeBSD: releng/8.0/sys/netgraph/ng_car.c 177732 2008-03-30 07:53:51Z mav $
   28  */
   29 
   30 /*
   31  * ng_car - An implementation of commited access rate for netgraph
   32  *
   33  * TODO:
   34  *      - Sanitize input config values (impose some limits)
   35  *      - Implement internal packet painting (possibly using mbuf tags)
   36  *      - Implement color-aware mode
   37  *      - Implement DSCP marking for IPv4
   38  */
   39 
   40 #include <sys/param.h>
   41 #include <sys/errno.h>
   42 #include <sys/kernel.h>
   43 #include <sys/malloc.h>
   44 #include <sys/mbuf.h>
   45 
   46 #include <netgraph/ng_message.h>
   47 #include <netgraph/ng_parse.h>
   48 #include <netgraph/netgraph.h>
   49 #include <netgraph/ng_car.h>
   50 
   51 #define NG_CAR_QUEUE_SIZE       100     /* Maximum queue size for SHAPE mode */
   52 #define NG_CAR_QUEUE_MIN_TH     8       /* Minimum RED threshhold for SHAPE mode */
   53 
   54 /* Hook private info */
   55 struct hookinfo {
   56         hook_p          hook;           /* this (source) hook */
   57         hook_p          dest;           /* destination hook */
   58 
   59         int64_t         tc;             /* commited token bucket counter */
   60         int64_t         te;             /* exceeded/peak token bucket counter */
   61         struct bintime  lastRefill;     /* last token refill time */
   62 
   63         struct ng_car_hookconf conf;    /* hook configuration */
   64         struct ng_car_hookstats stats;  /* hook stats */
   65 
   66         struct mbuf     *q[NG_CAR_QUEUE_SIZE];  /* circular packet queue */
   67         u_int           q_first;        /* first queue element */
   68         u_int           q_last;         /* last queue element */
   69         struct callout  q_callout;      /* periodic queue processing routine */
   70         struct mtx      q_mtx;          /* queue mutex */
   71 };
   72 
   73 /* Private information for each node instance */
   74 struct privdata {
   75         node_p node;                            /* the node itself */
   76         struct hookinfo upper;                  /* hook to upper layers */
   77         struct hookinfo lower;                  /* hook to lower layers */
   78 };
   79 typedef struct privdata *priv_p;
   80 
   81 static ng_constructor_t ng_car_constructor;
   82 static ng_rcvmsg_t      ng_car_rcvmsg;
   83 static ng_shutdown_t    ng_car_shutdown;
   84 static ng_newhook_t     ng_car_newhook;
   85 static ng_rcvdata_t     ng_car_rcvdata;
   86 static ng_disconnect_t  ng_car_disconnect;
   87 
   88 static void     ng_car_refillhook(struct hookinfo *h);
   89 static void     ng_car_schedule(struct hookinfo *h);
   90 void            ng_car_q_event(node_p node, hook_p hook, void *arg, int arg2);
   91 static void     ng_car_enqueue(struct hookinfo *h, item_p item);
   92 
   93 /* Parse type for struct ng_car_hookstats */
   94 static const struct ng_parse_struct_field ng_car_hookstats_type_fields[]
   95         = NG_CAR_HOOKSTATS;
   96 static const struct ng_parse_type ng_car_hookstats_type = {
   97         &ng_parse_struct_type,
   98         &ng_car_hookstats_type_fields
   99 };
  100 
  101 /* Parse type for struct ng_car_bulkstats */
  102 static const struct ng_parse_struct_field ng_car_bulkstats_type_fields[]
  103         = NG_CAR_BULKSTATS(&ng_car_hookstats_type);
  104 static const struct ng_parse_type ng_car_bulkstats_type = {
  105         &ng_parse_struct_type,
  106         &ng_car_bulkstats_type_fields
  107 };
  108 
  109 /* Parse type for struct ng_car_hookconf */
  110 static const struct ng_parse_struct_field ng_car_hookconf_type_fields[]
  111         = NG_CAR_HOOKCONF;
  112 static const struct ng_parse_type ng_car_hookconf_type = {
  113         &ng_parse_struct_type,
  114         &ng_car_hookconf_type_fields
  115 };
  116 
  117 /* Parse type for struct ng_car_bulkconf */
  118 static const struct ng_parse_struct_field ng_car_bulkconf_type_fields[]
  119         = NG_CAR_BULKCONF(&ng_car_hookconf_type);
  120 static const struct ng_parse_type ng_car_bulkconf_type = {
  121         &ng_parse_struct_type,
  122         &ng_car_bulkconf_type_fields
  123 };
  124 
  125 /* Command list */
  126 static struct ng_cmdlist ng_car_cmdlist[] = {
  127         {
  128           NGM_CAR_COOKIE,
  129           NGM_CAR_GET_STATS,
  130           "getstats",
  131           NULL,
  132           &ng_car_bulkstats_type,
  133         },
  134         {
  135           NGM_CAR_COOKIE,
  136           NGM_CAR_CLR_STATS,
  137           "clrstats",
  138           NULL,
  139           NULL,
  140         },
  141         {
  142           NGM_CAR_COOKIE,
  143           NGM_CAR_GETCLR_STATS,
  144           "getclrstats",
  145           NULL,
  146           &ng_car_bulkstats_type,
  147         },
  148 
  149         {
  150           NGM_CAR_COOKIE,
  151           NGM_CAR_GET_CONF,
  152           "getconf",
  153           NULL,
  154           &ng_car_bulkconf_type,
  155         },
  156         {
  157           NGM_CAR_COOKIE,
  158           NGM_CAR_SET_CONF,
  159           "setconf",
  160           &ng_car_bulkconf_type,
  161           NULL,
  162         },
  163         { 0 }
  164 };
  165 
  166 /* Netgraph node type descriptor */
  167 static struct ng_type ng_car_typestruct = {
  168         .version =      NG_ABI_VERSION,
  169         .name =         NG_CAR_NODE_TYPE,
  170         .constructor =  ng_car_constructor,
  171         .rcvmsg =       ng_car_rcvmsg,
  172         .shutdown =     ng_car_shutdown,
  173         .newhook =      ng_car_newhook,
  174         .rcvdata =      ng_car_rcvdata,
  175         .disconnect =   ng_car_disconnect,
  176         .cmdlist =      ng_car_cmdlist,
  177 };
  178 NETGRAPH_INIT(car, &ng_car_typestruct);
  179 
  180 /*
  181  * Node constructor
  182  */
  183 static int
  184 ng_car_constructor(node_p node)
  185 {
  186         priv_p priv;
  187 
  188         /* Initialize private descriptor. */
  189         priv = malloc(sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
  190         if (priv == NULL)
  191                 return (ENOMEM);
  192 
  193         NG_NODE_SET_PRIVATE(node, priv);
  194         priv->node = node;
  195 
  196         /*
  197          * Arbitrary default values
  198          */
  199 
  200         priv->upper.hook = NULL;
  201         priv->upper.dest = NULL;
  202         priv->upper.tc = priv->upper.conf.cbs = NG_CAR_CBS_MIN;
  203         priv->upper.te = priv->upper.conf.ebs = NG_CAR_EBS_MIN;
  204         priv->upper.conf.cir = NG_CAR_CIR_DFLT;
  205         priv->upper.conf.green_action = NG_CAR_ACTION_FORWARD;
  206         priv->upper.conf.yellow_action = NG_CAR_ACTION_FORWARD;
  207         priv->upper.conf.red_action = NG_CAR_ACTION_DROP;
  208         priv->upper.conf.mode = 0;
  209         getbinuptime(&priv->upper.lastRefill);
  210         priv->upper.q_first = 0;
  211         priv->upper.q_last = 0;
  212         ng_callout_init(&priv->upper.q_callout);
  213         mtx_init(&priv->upper.q_mtx, "ng_car_u", NULL, MTX_DEF);
  214 
  215         priv->lower.hook = NULL;
  216         priv->lower.dest = NULL;
  217         priv->lower.tc = priv->lower.conf.cbs = NG_CAR_CBS_MIN;
  218         priv->lower.te = priv->lower.conf.ebs = NG_CAR_EBS_MIN;
  219         priv->lower.conf.cir = NG_CAR_CIR_DFLT;
  220         priv->lower.conf.green_action = NG_CAR_ACTION_FORWARD;
  221         priv->lower.conf.yellow_action = NG_CAR_ACTION_FORWARD;
  222         priv->lower.conf.red_action = NG_CAR_ACTION_DROP;
  223         priv->lower.conf.mode = 0;
  224         priv->lower.lastRefill = priv->upper.lastRefill;
  225         priv->lower.q_first = 0;
  226         priv->lower.q_last = 0;
  227         ng_callout_init(&priv->lower.q_callout);
  228         mtx_init(&priv->lower.q_mtx, "ng_car_l", NULL, MTX_DEF);
  229 
  230         return (0);
  231 }
  232 
  233 /*
  234  * Add a hook.
  235  */
  236 static int
  237 ng_car_newhook(node_p node, hook_p hook, const char *name)
  238 {
  239         const priv_p priv = NG_NODE_PRIVATE(node);
  240 
  241         if (strcmp(name, NG_CAR_HOOK_LOWER) == 0) {
  242                 priv->lower.hook = hook;
  243                 priv->upper.dest = hook;
  244                 bzero(&priv->lower.stats, sizeof(priv->lower.stats));
  245                 NG_HOOK_SET_PRIVATE(hook, &priv->lower);
  246         } else if (strcmp(name, NG_CAR_HOOK_UPPER) == 0) {
  247                 priv->upper.hook = hook;
  248                 priv->lower.dest = hook;
  249                 bzero(&priv->upper.stats, sizeof(priv->upper.stats));
  250                 NG_HOOK_SET_PRIVATE(hook, &priv->upper);
  251         } else
  252                 return (EINVAL);
  253         return(0);
  254 }
  255 
  256 /*
  257  * Data has arrived.
  258  */
  259 static int
  260 ng_car_rcvdata(hook_p hook, item_p item )
  261 {
  262         struct hookinfo *const hinfo = NG_HOOK_PRIVATE(hook);
  263         struct mbuf *m;
  264         int error = 0;
  265         u_int len;
  266 
  267         /* If queue is not empty now then enqueue packet. */
  268         if (hinfo->q_first != hinfo->q_last) {
  269                 ng_car_enqueue(hinfo, item);
  270                 return (0);
  271         }
  272 
  273         m = NGI_M(item);
  274 
  275 #define NG_CAR_PERFORM_MATCH_ACTION(a)                  \
  276         do {                                            \
  277                 switch (a) {                            \
  278                 case NG_CAR_ACTION_FORWARD:             \
  279                         /* Do nothing. */               \
  280                         break;                          \
  281                 case NG_CAR_ACTION_MARK:                \
  282                         /* XXX find a way to mark packets (mbuf tag?) */ \
  283                         ++hinfo->stats.errors;          \
  284                         break;                          \
  285                 case NG_CAR_ACTION_DROP:                \
  286                 default:                                \
  287                         /* Drop packet and return. */   \
  288                         NG_FREE_ITEM(item);             \
  289                         ++hinfo->stats.droped_pkts;     \
  290                         return (0);                     \
  291                 }                                       \
  292         } while (0)
  293 
  294         /* Packet is counted as 128 tokens for better resolution */
  295         if (hinfo->conf.opt & NG_CAR_COUNT_PACKETS) {
  296                 len = 128;
  297         } else {
  298                 len = m->m_pkthdr.len;
  299         }
  300 
  301         /* Check commited token bucket. */
  302         if (hinfo->tc - len >= 0) {
  303                 /* This packet is green. */
  304                 ++hinfo->stats.green_pkts;
  305                 hinfo->tc -= len;
  306                 NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.green_action);
  307         } else {
  308 
  309                 /* Refill only if not green without it. */
  310                 ng_car_refillhook(hinfo);
  311 
  312                  /* Check commited token bucket again after refill. */
  313                 if (hinfo->tc - len >= 0) {
  314                         /* This packet is green */
  315                         ++hinfo->stats.green_pkts;
  316                         hinfo->tc -= len;
  317                         NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.green_action);
  318 
  319                 /* If not green and mode is SHAPE, enqueue packet. */
  320                 } else if (hinfo->conf.mode == NG_CAR_SHAPE) {
  321                         ng_car_enqueue(hinfo, item);
  322                         return (0);
  323 
  324                 /* If not green and mode is RED, calculate probability. */
  325                 } else if (hinfo->conf.mode == NG_CAR_RED) {
  326                         /* Is packet is bigger then extended burst? */
  327                         if (len - (hinfo->tc - len) > hinfo->conf.ebs) {
  328                                 /* This packet is definitely red. */
  329                                 ++hinfo->stats.red_pkts;
  330                                 hinfo->te = 0;
  331                                 NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.red_action);
  332 
  333                         /* Use token bucket to simulate RED-like drop
  334                            probability. */
  335                         } else if (hinfo->te + (len - hinfo->tc) <
  336                             hinfo->conf.ebs) {
  337                                 /* This packet is yellow */
  338                                 ++hinfo->stats.yellow_pkts;
  339                                 hinfo->te += len - hinfo->tc;
  340                                 /* Go to negative tokens. */
  341                                 hinfo->tc -= len;
  342                                 NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.yellow_action);
  343                         } else {
  344                                 /* This packet is probaly red. */
  345                                 ++hinfo->stats.red_pkts;
  346                                 hinfo->te = 0;
  347                                 NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.red_action);
  348                         }
  349                 /* If not green and mode is SINGLE/DOUBLE RATE. */
  350                 } else {
  351                         /* Check extended token bucket. */
  352                         if (hinfo->te - len >= 0) {
  353                                 /* This packet is yellow */
  354                                 ++hinfo->stats.yellow_pkts;
  355                                 hinfo->te -= len;
  356                                 NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.yellow_action);
  357                         } else {
  358                                 /* This packet is red */
  359                                 ++hinfo->stats.red_pkts;
  360                                 NG_CAR_PERFORM_MATCH_ACTION(hinfo->conf.red_action);
  361                         }
  362                 }
  363         }
  364 
  365 #undef NG_CAR_PERFORM_MATCH_ACTION
  366 
  367         NG_FWD_ITEM_HOOK(error, item, hinfo->dest);
  368         if (error != 0)
  369                 ++hinfo->stats.errors;
  370         ++hinfo->stats.passed_pkts;
  371 
  372         return (error);
  373 }
  374 
  375 /*
  376  * Receive a control message.
  377  */
  378 static int
  379 ng_car_rcvmsg(node_p node, item_p item, hook_p lasthook)
  380 {
  381         const priv_p priv = NG_NODE_PRIVATE(node);
  382         struct ng_mesg *resp = NULL;
  383         int error = 0;
  384         struct ng_mesg *msg;
  385 
  386         NGI_GET_MSG(item, msg);
  387         switch (msg->header.typecookie) {
  388         case NGM_CAR_COOKIE:
  389                 switch (msg->header.cmd) {
  390                 case NGM_CAR_GET_STATS:
  391                 case NGM_CAR_GETCLR_STATS:
  392                         {
  393                                 struct ng_car_bulkstats *bstats;
  394 
  395                                 NG_MKRESPONSE(resp, msg,
  396                                         sizeof(*bstats), M_NOWAIT);
  397                                 if (resp == NULL) {
  398                                         error = ENOMEM;
  399                                         break;
  400                                 }
  401                                 bstats = (struct ng_car_bulkstats *)resp->data;
  402 
  403                                 bcopy(&priv->upper.stats, &bstats->downstream,
  404                                     sizeof(bstats->downstream));
  405                                 bcopy(&priv->lower.stats, &bstats->upstream,
  406                                     sizeof(bstats->upstream));
  407                         }
  408                         if (msg->header.cmd == NGM_CAR_GET_STATS)
  409                                 break;
  410                 case NGM_CAR_CLR_STATS:
  411                         bzero(&priv->upper.stats,
  412                                 sizeof(priv->upper.stats));
  413                         bzero(&priv->lower.stats,
  414                                 sizeof(priv->lower.stats));
  415                         break;
  416                 case NGM_CAR_GET_CONF:
  417                         {
  418                                 struct ng_car_bulkconf *bconf;
  419 
  420                                 NG_MKRESPONSE(resp, msg,
  421                                         sizeof(*bconf), M_NOWAIT);
  422                                 if (resp == NULL) {
  423                                         error = ENOMEM;
  424                                         break;
  425                                 }
  426                                 bconf = (struct ng_car_bulkconf *)resp->data;
  427 
  428                                 bcopy(&priv->upper.conf, &bconf->downstream,
  429                                     sizeof(bconf->downstream));
  430                                 bcopy(&priv->lower.conf, &bconf->upstream,
  431                                     sizeof(bconf->upstream));
  432                                 /* Convert internal 1/(8*128) of pps into pps */
  433                                 if (bconf->downstream.opt & NG_CAR_COUNT_PACKETS) {
  434                                     bconf->downstream.cir /= 1024;
  435                                     bconf->downstream.pir /= 1024;
  436                                     bconf->downstream.cbs /= 128;
  437                                     bconf->downstream.ebs /= 128;
  438                                 }
  439                                 if (bconf->upstream.opt & NG_CAR_COUNT_PACKETS) {
  440                                     bconf->upstream.cir /= 1024;
  441                                     bconf->upstream.pir /= 1024;
  442                                     bconf->upstream.cbs /= 128;
  443                                     bconf->upstream.ebs /= 128;
  444                                 }
  445                         }
  446                         break;
  447                 case NGM_CAR_SET_CONF:
  448                         {
  449                                 struct ng_car_bulkconf *const bconf =
  450                                 (struct ng_car_bulkconf *)msg->data;
  451 
  452                                 /* Check for invalid or illegal config. */
  453                                 if (msg->header.arglen != sizeof(*bconf)) {
  454                                         error = EINVAL;
  455                                         break;
  456                                 }
  457                                 /* Convert pps into internal 1/(8*128) of pps */
  458                                 if (bconf->downstream.opt & NG_CAR_COUNT_PACKETS) {
  459                                     bconf->downstream.cir *= 1024;
  460                                     bconf->downstream.pir *= 1024;
  461                                     bconf->downstream.cbs *= 125;
  462                                     bconf->downstream.ebs *= 125;
  463                                 }
  464                                 if (bconf->upstream.opt & NG_CAR_COUNT_PACKETS) {
  465                                     bconf->upstream.cir *= 1024;
  466                                     bconf->upstream.pir *= 1024;
  467                                     bconf->upstream.cbs *= 125;
  468                                     bconf->upstream.ebs *= 125;
  469                                 }
  470                                 if ((bconf->downstream.cir > 1000000000) ||
  471                                     (bconf->downstream.pir > 1000000000) ||
  472                                     (bconf->upstream.cir > 1000000000) ||
  473                                     (bconf->upstream.pir > 1000000000) ||
  474                                     (bconf->downstream.cbs == 0 &&
  475                                         bconf->downstream.ebs == 0) ||
  476                                     (bconf->upstream.cbs == 0 &&
  477                                         bconf->upstream.ebs == 0))
  478                                 {
  479                                         error = EINVAL;
  480                                         break;
  481                                 }
  482                                 if ((bconf->upstream.mode == NG_CAR_SHAPE) &&
  483                                     (bconf->upstream.cir == 0)) {
  484                                         error = EINVAL;
  485                                         break;
  486                                 }
  487                                 if ((bconf->downstream.mode == NG_CAR_SHAPE) &&
  488                                     (bconf->downstream.cir == 0)) {
  489                                         error = EINVAL;
  490                                         break;
  491                                 }
  492 
  493                                 /* Copy downstream config. */
  494                                 bcopy(&bconf->downstream, &priv->upper.conf,
  495                                     sizeof(priv->upper.conf));
  496                                 priv->upper.tc = priv->upper.conf.cbs;
  497                                 if (priv->upper.conf.mode == NG_CAR_RED ||
  498                                     priv->upper.conf.mode == NG_CAR_SHAPE) {
  499                                         priv->upper.te = 0;
  500                                 } else {
  501                                         priv->upper.te = priv->upper.conf.ebs;
  502                                 }
  503 
  504                                 /* Copy upstream config. */
  505                                 bcopy(&bconf->upstream, &priv->lower.conf,
  506                                     sizeof(priv->lower.conf));
  507                                 priv->lower.tc = priv->lower.conf.cbs;
  508                                 if (priv->lower.conf.mode == NG_CAR_RED ||
  509                                     priv->lower.conf.mode == NG_CAR_SHAPE) {
  510                                         priv->lower.te = 0;
  511                                 } else {
  512                                         priv->lower.te = priv->lower.conf.ebs;
  513                                 }
  514                         }
  515                         break;
  516                 default:
  517                         error = EINVAL;
  518                         break;
  519                 }
  520                 break;
  521         default:
  522                 error = EINVAL;
  523                 break;
  524         }
  525         NG_RESPOND_MSG(error, node, item, resp);
  526         NG_FREE_MSG(msg);
  527         return (error);
  528 }
  529 
  530 /*
  531  * Do local shutdown processing.
  532  */
  533 static int
  534 ng_car_shutdown(node_p node)
  535 {
  536         const priv_p priv = NG_NODE_PRIVATE(node);
  537 
  538         ng_uncallout(&priv->upper.q_callout, node);
  539         ng_uncallout(&priv->lower.q_callout, node);
  540         mtx_destroy(&priv->upper.q_mtx);
  541         mtx_destroy(&priv->lower.q_mtx);
  542         NG_NODE_UNREF(priv->node);
  543         free(priv, M_NETGRAPH);
  544         return (0);
  545 }
  546 
  547 /*
  548  * Hook disconnection.
  549  *
  550  * For this type, removal of the last link destroys the node.
  551  */
  552 static int
  553 ng_car_disconnect(hook_p hook)
  554 {
  555         struct hookinfo *const hinfo = NG_HOOK_PRIVATE(hook);
  556         const node_p node = NG_HOOK_NODE(hook);
  557         const priv_p priv = NG_NODE_PRIVATE(node);
  558 
  559         if (hinfo) {
  560                 /* Purge queue if not empty. */
  561                 while (hinfo->q_first != hinfo->q_last) {
  562                         NG_FREE_M(hinfo->q[hinfo->q_first]);
  563                         hinfo->q_first++;
  564                         if (hinfo->q_first >= NG_CAR_QUEUE_SIZE)
  565                                 hinfo->q_first = 0;
  566                 }
  567                 /* Remove hook refs. */
  568                 if (hinfo->hook == priv->upper.hook)
  569                         priv->lower.dest = NULL;
  570                 else
  571                         priv->upper.dest = NULL;
  572                 hinfo->hook = NULL;
  573         }
  574         /* Already shutting down? */
  575         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
  576             && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
  577                 ng_rmnode_self(NG_HOOK_NODE(hook));
  578         return (0);
  579 }
  580 
  581 /*
  582  * Hook's token buckets refillment.
  583  */
  584 static void
  585 ng_car_refillhook(struct hookinfo *h)
  586 {
  587         struct bintime newt, deltat;
  588         unsigned int deltat_us;
  589 
  590         /* Get current time. */
  591         getbinuptime(&newt);
  592 
  593         /* Get time delta since last refill. */
  594         deltat = newt;
  595         bintime_sub(&deltat, &h->lastRefill);
  596 
  597         /* Time must go forward. */
  598         if (deltat.sec < 0) {
  599             h->lastRefill = newt;
  600             return;
  601         }
  602 
  603         /* But not too far forward. */
  604         if (deltat.sec >= 1000) {
  605             deltat_us = (1000 << 20);
  606         } else {
  607             /* convert bintime to the 1/(2^20) of sec */
  608             deltat_us = (deltat.sec << 20) + (deltat.frac >> 44);
  609         }
  610 
  611         if (h->conf.mode == NG_CAR_SINGLE_RATE) {
  612                 int64_t delta;
  613                 /* Refill commited token bucket. */
  614                 h->tc += (h->conf.cir * deltat_us) >> 23;
  615                 delta = h->tc - h->conf.cbs;
  616                 if (delta > 0) {
  617                         h->tc = h->conf.cbs;
  618 
  619                         /* Refill exceeded token bucket. */
  620                         h->te += delta;
  621                         if (h->te > ((int64_t)h->conf.ebs))
  622                                 h->te = h->conf.ebs;
  623                 }
  624 
  625         } else if (h->conf.mode == NG_CAR_DOUBLE_RATE) {
  626                 /* Refill commited token bucket. */
  627                 h->tc += (h->conf.cir * deltat_us) >> 23;
  628                 if (h->tc > ((int64_t)h->conf.cbs))
  629                         h->tc = h->conf.cbs;
  630 
  631                 /* Refill peak token bucket. */
  632                 h->te += (h->conf.pir * deltat_us) >> 23;
  633                 if (h->te > ((int64_t)h->conf.ebs))
  634                         h->te = h->conf.ebs;
  635 
  636         } else { /* RED or SHAPE mode. */
  637                 /* Refill commited token bucket. */
  638                 h->tc += (h->conf.cir * deltat_us) >> 23;
  639                 if (h->tc > ((int64_t)h->conf.cbs))
  640                         h->tc = h->conf.cbs;
  641         }
  642 
  643         /* Remember this moment. */
  644         h->lastRefill = newt;
  645 }
  646 
  647 /*
  648  * Schedule callout when we will have required tokens.
  649  */
  650 static void
  651 ng_car_schedule(struct hookinfo *hinfo)
  652 {
  653         int     delay;
  654 
  655         delay = (-(hinfo->tc)) * hz * 8 / hinfo->conf.cir + 1;
  656 
  657         ng_callout(&hinfo->q_callout, NG_HOOK_NODE(hinfo->hook), hinfo->hook,
  658             delay, &ng_car_q_event, NULL, 0);
  659 }
  660 
  661 /*
  662  * Queue processing callout handler.
  663  */
  664 void
  665 ng_car_q_event(node_p node, hook_p hook, void *arg, int arg2)
  666 {
  667         struct hookinfo *hinfo = NG_HOOK_PRIVATE(hook);
  668         struct mbuf     *m;
  669         int             error;
  670 
  671         /* Refill tokens for time we have slept. */
  672         ng_car_refillhook(hinfo);
  673 
  674         /* If we have some tokens */
  675         while (hinfo->tc >= 0) {
  676 
  677                 /* Send packet. */
  678                 m = hinfo->q[hinfo->q_first];
  679                 NG_SEND_DATA_ONLY(error, hinfo->dest, m);
  680                 if (error != 0)
  681                         ++hinfo->stats.errors;
  682                 ++hinfo->stats.passed_pkts;
  683 
  684                 /* Get next one. */
  685                 hinfo->q_first++;
  686                 if (hinfo->q_first >= NG_CAR_QUEUE_SIZE)
  687                         hinfo->q_first = 0;
  688 
  689                 /* Stop if none left. */
  690                 if (hinfo->q_first == hinfo->q_last)
  691                         break;
  692 
  693                 /* If we have more packet, try it. */
  694                 m = hinfo->q[hinfo->q_first];
  695                 if (hinfo->conf.opt & NG_CAR_COUNT_PACKETS) {
  696                         hinfo->tc -= 128;
  697                 } else {
  698                         hinfo->tc -= m->m_pkthdr.len;
  699                 }
  700         }
  701 
  702         /* If something left */
  703         if (hinfo->q_first != hinfo->q_last)
  704                 /* Schedule queue processing. */
  705                 ng_car_schedule(hinfo);
  706 }
  707 
  708 /*
  709  * Enqueue packet.
  710  */
  711 static void
  712 ng_car_enqueue(struct hookinfo *hinfo, item_p item)
  713 {
  714         struct mbuf     *m;
  715         int             len;
  716 
  717         NGI_GET_M(item, m);
  718         NG_FREE_ITEM(item);
  719 
  720         /* Lock queue mutex. */
  721         mtx_lock(&hinfo->q_mtx);
  722 
  723         /* Calculate used queue length. */
  724         len = hinfo->q_last - hinfo->q_first;
  725         if (len < 0)
  726                 len += NG_CAR_QUEUE_SIZE;
  727 
  728         /* If queue is overflowed or we have no RED tokens. */
  729         if ((len >= (NG_CAR_QUEUE_SIZE - 1)) ||
  730             (hinfo->te + len >= NG_CAR_QUEUE_SIZE)) {
  731                 /* Drop packet. */
  732                 ++hinfo->stats.red_pkts;
  733                 ++hinfo->stats.droped_pkts;
  734                 NG_FREE_M(m);
  735 
  736                 hinfo->te = 0;
  737         } else {
  738                 /* This packet is yellow. */
  739                 ++hinfo->stats.yellow_pkts;
  740 
  741                 /* Enqueue packet. */
  742                 hinfo->q[hinfo->q_last] = m;
  743                 hinfo->q_last++;
  744                 if (hinfo->q_last >= NG_CAR_QUEUE_SIZE)
  745                         hinfo->q_last = 0;
  746 
  747                 /* Use RED tokens. */
  748                 if (len > NG_CAR_QUEUE_MIN_TH)
  749                         hinfo->te += len - NG_CAR_QUEUE_MIN_TH;
  750 
  751                 /* If this is a first packet in the queue. */
  752                 if (len == 0) {
  753                         if (hinfo->conf.opt & NG_CAR_COUNT_PACKETS) {
  754                                 hinfo->tc -= 128;
  755                         } else {
  756                                 hinfo->tc -= m->m_pkthdr.len;
  757                         }
  758 
  759                         /* Schedule queue processing. */
  760                         ng_car_schedule(hinfo);
  761                 }
  762         }
  763 
  764         /* Unlock queue mutex. */
  765         mtx_unlock(&hinfo->q_mtx);
  766 }

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