sys/netgraph/ppp/ng_ppp.c

   1
   2 /*
   3  * ng_ppp.c
   4  *
   5  * Copyright (c) 1996-2000 Whistle Communications, Inc.
   6  * All rights reserved.
   7  *
   8  * Subject to the following obligations and disclaimer of warranty, use and
   9  * redistribution of this software, in source or object code forms, with or
  10  * without modifications are expressly permitted by Whistle Communications;
  11  * provided, however, that:
  12  * 1. Any and all reproductions of the source or object code must include the
  13  *    copyright notice above and the following disclaimer of warranties; and
  14  * 2. No rights are granted, in any manner or form, to use Whistle
  15  *    Communications, Inc. trademarks, including the mark "WHISTLE
  16  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  17  *    such appears in the above copyright notice or in the software.
  18  *
  19  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  20  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  21  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  22  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  23  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  24  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  25  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  26  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  27  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  28  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  29  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  30  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  31  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  35  * OF SUCH DAMAGE.
  36  *
  37  * Author: Archie Cobbs <archie@freebsd.org>
  38  *
  39  * $FreeBSD: src/sys/netgraph/ng_ppp.c,v 1.15.2.10 2003/03/10 17:55:48 archie Exp $
  40  * $DragonFly: src/sys/netgraph/ppp/ng_ppp.c,v 1.13 2008/01/05 14:02:39 swildner Exp $
  41  * $Whistle: ng_ppp.c,v 1.24 1999/11/01 09:24:52 julian Exp $
  42  */
  43
  44 /*
  45  * PPP node type.
  46  */
  47
  48 #include <sys/param.h>
  49 #include <sys/systm.h>
  50 #include <sys/kernel.h>
  51 #include <sys/time.h>
  52 #include <sys/mbuf.h>
  53 #include <sys/malloc.h>
  54 #include <sys/errno.h>
  55 #include <sys/ctype.h>
  56 #include <sys/thread2.h>
  57
  58 #include <machine/limits.h>
  59
  60 #include <netgraph/ng_message.h>
  61 #include <netgraph/netgraph.h>
  62 #include <netgraph/ng_parse.h>
  63 #include "ng_ppp.h"
  64 #include <netgraph/vjc/ng_vjc.h>
  65
  66 #define PROT_VALID(p)           (((p) & 0x0101) == 0x0001)
  67 #define PROT_COMPRESSABLE(p)    (((p) & 0xff00) == 0x0000)
  68
  69 /* Some PPP protocol numbers we're interested in */
  70 #define PROT_APPLETALK          0x0029
  71 #define PROT_COMPD              0x00fd
  72 #define PROT_CRYPTD             0x0053
  73 #define PROT_IP                 0x0021
  74 #define PROT_IPV6               0x0057
  75 #define PROT_IPX                0x002b
  76 #define PROT_LCP                0xc021
  77 #define PROT_MP                 0x003d
  78 #define PROT_VJCOMP             0x002d
  79 #define PROT_VJUNCOMP           0x002f
  80
  81 /* Multilink PPP definitions */
  82 #define MP_MIN_MRRU             1500            /* per RFC 1990 */
  83 #define MP_INITIAL_SEQ          0               /* per RFC 1990 */
  84 #define MP_MIN_LINK_MRU         32
  85
  86 #define MP_SHORT_SEQ_MASK       0x00000fff      /* short seq # mask */
  87 #define MP_SHORT_SEQ_HIBIT      0x00000800      /* short seq # high bit */
  88 #define MP_SHORT_FIRST_FLAG     0x00008000      /* first fragment in frame */
  89 #define MP_SHORT_LAST_FLAG      0x00004000      /* last fragment in frame */
  90
  91 #define MP_LONG_SEQ_MASK        0x00ffffff      /* long seq # mask */
  92 #define MP_LONG_SEQ_HIBIT       0x00800000      /* long seq # high bit */
  93 #define MP_LONG_FIRST_FLAG      0x80000000      /* first fragment in frame */
  94 #define MP_LONG_LAST_FLAG       0x40000000      /* last fragment in frame */
  95
  96 #define MP_NOSEQ                0x7fffffff      /* impossible sequence number */
  97
  98 /* Sign extension of MP sequence numbers */
  99 #define MP_SHORT_EXTEND(s)      (((s) & MP_SHORT_SEQ_HIBIT) ?           \
 100                                     ((s) | ~MP_SHORT_SEQ_MASK)          \
 101                                     : ((s) & MP_SHORT_SEQ_MASK))
 102 #define MP_LONG_EXTEND(s)       (((s) & MP_LONG_SEQ_HIBIT) ?            \
 103                                     ((s) | ~MP_LONG_SEQ_MASK)           \
 104                                     : ((s) & MP_LONG_SEQ_MASK))
 105
 106 /* Comparision of MP sequence numbers. Note: all sequence numbers
 107    except priv->xseq are stored with the sign bit extended. */
 108 #define MP_SHORT_SEQ_DIFF(x,y)  MP_SHORT_EXTEND((x) - (y))
 109 #define MP_LONG_SEQ_DIFF(x,y)   MP_LONG_EXTEND((x) - (y))
 110
 111 #define MP_RECV_SEQ_DIFF(priv,x,y)                                      \
 112                                 ((priv)->conf.recvShortSeq ?            \
 113                                     MP_SHORT_SEQ_DIFF((x), (y)) :       \
 114                                     MP_LONG_SEQ_DIFF((x), (y)))
 115
 116 /* Increment receive sequence number */
 117 #define MP_NEXT_RECV_SEQ(priv,seq)                                      \
 118                                 ((priv)->conf.recvShortSeq ?            \
 119                                     MP_SHORT_EXTEND((seq) + 1) :        \
 120                                     MP_LONG_EXTEND((seq) + 1))
 121
 122 /* Don't fragment transmitted packets smaller than this */
 123 #define MP_MIN_FRAG_LEN         6
 124
 125 /* Maximum fragment reasssembly queue length */
 126 #define MP_MAX_QUEUE_LEN        128
 127
 128 /* Fragment queue scanner period */
 129 #define MP_FRAGTIMER_INTERVAL   (hz/2)
 130
 131 /* We store incoming fragments this way */
 132 struct ng_ppp_frag {
 133         int                             seq;            /* fragment seq# */
 134         u_char                          first;          /* First in packet? */
 135         u_char                          last;           /* Last in packet? */
 136         struct timeval                  timestamp;      /* time of reception */
 137         struct mbuf                     *data;          /* Fragment data */
 138         meta_p                          meta;           /* Fragment meta */
 139         CIRCLEQ_ENTRY(ng_ppp_frag)      f_qent;         /* Fragment queue */
 140 };
 141
 142 /* We use integer indicies to refer to the non-link hooks */
 143 static const char *const ng_ppp_hook_names[] = {
 144         NG_PPP_HOOK_ATALK,
 145 #define HOOK_INDEX_ATALK                0
 146         NG_PPP_HOOK_BYPASS,
 147 #define HOOK_INDEX_BYPASS               1
 148         NG_PPP_HOOK_COMPRESS,
 149 #define HOOK_INDEX_COMPRESS             2
 150         NG_PPP_HOOK_ENCRYPT,
 151 #define HOOK_INDEX_ENCRYPT              3
 152         NG_PPP_HOOK_DECOMPRESS,
 153 #define HOOK_INDEX_DECOMPRESS           4
 154         NG_PPP_HOOK_DECRYPT,
 155 #define HOOK_INDEX_DECRYPT              5
 156         NG_PPP_HOOK_INET,
 157 #define HOOK_INDEX_INET                 6
 158         NG_PPP_HOOK_IPX,
 159 #define HOOK_INDEX_IPX                  7
 160         NG_PPP_HOOK_VJC_COMP,
 161 #define HOOK_INDEX_VJC_COMP             8
 162         NG_PPP_HOOK_VJC_IP,
 163 #define HOOK_INDEX_VJC_IP               9
 164         NG_PPP_HOOK_VJC_UNCOMP,
 165 #define HOOK_INDEX_VJC_UNCOMP           10
 166         NG_PPP_HOOK_VJC_VJIP,
 167 #define HOOK_INDEX_VJC_VJIP             11
 168         NG_PPP_HOOK_IPV6,
 169 #define HOOK_INDEX_IPV6                 12
 170         NULL
 171 #define HOOK_INDEX_MAX                  13
 172 };
 173
 174 /* We store index numbers in the hook private pointer. The HOOK_INDEX()
 175    for a hook is either the index (above) for normal hooks, or the ones
 176    complement of the link number for link hooks. */
 177 #define HOOK_INDEX(hook)        (*((int16_t *) &(hook)->private))
 178
 179 /* Per-link private information */
 180 struct ng_ppp_link {
 181         struct ng_ppp_link_conf conf;           /* link configuration */
 182         hook_p                  hook;           /* connection to link data */
 183         int32_t                 seq;            /* highest rec'd seq# - MSEQ */
 184         struct timeval          lastWrite;      /* time of last write */
 185         int                     bytesInQueue;   /* bytes in the output queue */
 186         struct ng_ppp_link_stat stats;          /* Link stats */
 187 };
 188
 189 /* Total per-node private information */
 190 struct ng_ppp_private {
 191         struct ng_ppp_bund_conf conf;                   /* bundle config */
 192         struct ng_ppp_link_stat bundleStats;            /* bundle stats */
 193         struct ng_ppp_link      links[NG_PPP_MAX_LINKS];/* per-link info */
 194         int32_t                 xseq;                   /* next out MP seq # */
 195         int32_t                 mseq;                   /* min links[i].seq */
 196         u_char                  vjCompHooked;           /* VJ comp hooked up? */
 197         u_char                  allLinksEqual;          /* all xmit the same? */
 198         u_char                  timerActive;            /* frag timer active? */
 199         u_int                   numActiveLinks;         /* how many links up */
 200         int                     activeLinks[NG_PPP_MAX_LINKS];  /* indicies */
 201         u_int                   lastLink;               /* for round robin */
 202         hook_p                  hooks[HOOK_INDEX_MAX];  /* non-link hooks */
 203         CIRCLEQ_HEAD(ng_ppp_fraglist, ng_ppp_frag)      /* fragment queue */
 204                                 frags;
 205         int                     qlen;                   /* fraq queue length */
 206         struct callout          fragTimer;              /* fraq queue check */
 207 };
 208 typedef struct ng_ppp_private *priv_p;
 209
 210 /* Netgraph node methods */
 211 static ng_constructor_t ng_ppp_constructor;
 212 static ng_rcvmsg_t      ng_ppp_rcvmsg;
 213 static ng_shutdown_t    ng_ppp_rmnode;
 214 static ng_newhook_t     ng_ppp_newhook;
 215 static ng_rcvdata_t     ng_ppp_rcvdata;
 216 static ng_disconnect_t  ng_ppp_disconnect;
 217
 218 /* Helper functions */
 219 static int      ng_ppp_input(node_p node, int bypass,
 220                         int linkNum, struct mbuf *m, meta_p meta);
 221 static int      ng_ppp_output(node_p node, int bypass, int proto,
 222                         int linkNum, struct mbuf *m, meta_p meta);
 223 static int      ng_ppp_mp_input(node_p node, int linkNum,
 224                         struct mbuf *m, meta_p meta);
 225 static int      ng_ppp_check_packet(node_p node);
 226 static void     ng_ppp_get_packet(node_p node, struct mbuf **mp, meta_p *metap);
 227 static int      ng_ppp_frag_process(node_p node);
 228 static int      ng_ppp_frag_trim(node_p node);
 229 static void     ng_ppp_frag_timeout(void *arg);
 230 static void     ng_ppp_frag_checkstale(node_p node);
 231 static void     ng_ppp_frag_reset(node_p node);
 232 static int      ng_ppp_mp_output(node_p node, struct mbuf *m, meta_p meta);
 233 static void     ng_ppp_mp_strategy(node_p node, int len, int *distrib);
 234 static int      ng_ppp_intcmp(const void *v1, const void *v2);
 235 static struct   mbuf *ng_ppp_addproto(struct mbuf *m, int proto, int compOK);
 236 static struct   mbuf *ng_ppp_prepend(struct mbuf *m, const void *buf, int len);
 237 static int      ng_ppp_config_valid(node_p node,
 238                         const struct ng_ppp_node_conf *newConf);
 239 static void     ng_ppp_update(node_p node, int newConf);
 240 static void     ng_ppp_start_frag_timer(node_p node);
 241 static void     ng_ppp_stop_frag_timer(node_p node);
 242
 243 /* Parse type for struct ng_ppp_mp_state_type */
 244 static const struct ng_parse_fixedarray_info ng_ppp_rseq_array_info = {
 245         &ng_parse_hint32_type,
 246         NG_PPP_MAX_LINKS
 247 };
 248 static const struct ng_parse_type ng_ppp_rseq_array_type = {
 249         &ng_parse_fixedarray_type,
 250         &ng_ppp_rseq_array_info,
 251 };
 252 static const struct ng_parse_struct_field ng_ppp_mp_state_type_fields[]
 253         = NG_PPP_MP_STATE_TYPE_INFO(&ng_ppp_rseq_array_type);
 254 static const struct ng_parse_type ng_ppp_mp_state_type = {
 255         &ng_parse_struct_type,
 256         &ng_ppp_mp_state_type_fields
 257 };
 258
 259 /* Parse type for struct ng_ppp_link_conf */
 260 static const struct ng_parse_struct_field ng_ppp_link_type_fields[]
 261         = NG_PPP_LINK_TYPE_INFO;
 262 static const struct ng_parse_type ng_ppp_link_type = {
 263         &ng_parse_struct_type,
 264         &ng_ppp_link_type_fields
 265 };
 266
 267 /* Parse type for struct ng_ppp_bund_conf */
 268 static const struct ng_parse_struct_field ng_ppp_bund_type_fields[]
 269         = NG_PPP_BUND_TYPE_INFO;
 270 static const struct ng_parse_type ng_ppp_bund_type = {
 271         &ng_parse_struct_type,
 272         &ng_ppp_bund_type_fields
 273 };
 274
 275 /* Parse type for struct ng_ppp_node_conf */
 276 static const struct ng_parse_fixedarray_info ng_ppp_array_info = {
 277         &ng_ppp_link_type,
 278         NG_PPP_MAX_LINKS
 279 };
 280 static const struct ng_parse_type ng_ppp_link_array_type = {
 281         &ng_parse_fixedarray_type,
 282         &ng_ppp_array_info,
 283 };
 284 static const struct ng_parse_struct_field ng_ppp_conf_type_fields[]
 285         = NG_PPP_CONFIG_TYPE_INFO(&ng_ppp_bund_type, &ng_ppp_link_array_type);
 286 static const struct ng_parse_type ng_ppp_conf_type = {
 287         &ng_parse_struct_type,
 288         &ng_ppp_conf_type_fields
 289 };
 290
 291 /* Parse type for struct ng_ppp_link_stat */
 292 static const struct ng_parse_struct_field ng_ppp_stats_type_fields[]
 293         = NG_PPP_STATS_TYPE_INFO;
 294 static const struct ng_parse_type ng_ppp_stats_type = {
 295         &ng_parse_struct_type,
 296         &ng_ppp_stats_type_fields
 297 };
 298
 299 /* List of commands and how to convert arguments to/from ASCII */
 300 static const struct ng_cmdlist ng_ppp_cmds[] = {
 301         {
 302           NGM_PPP_COOKIE,
 303           NGM_PPP_SET_CONFIG,
 304           "setconfig",
 305           &ng_ppp_conf_type,
 306           NULL
 307         },
 308         {
 309           NGM_PPP_COOKIE,
 310           NGM_PPP_GET_CONFIG,
 311           "getconfig",
 312           NULL,
 313           &ng_ppp_conf_type
 314         },
 315         {
 316           NGM_PPP_COOKIE,
 317           NGM_PPP_GET_MP_STATE,
 318           "getmpstate",
 319           NULL,
 320           &ng_ppp_mp_state_type
 321         },
 322         {
 323           NGM_PPP_COOKIE,
 324           NGM_PPP_GET_LINK_STATS,
 325           "getstats",
 326           &ng_parse_int16_type,
 327           &ng_ppp_stats_type
 328         },
 329         {
 330           NGM_PPP_COOKIE,
 331           NGM_PPP_CLR_LINK_STATS,
 332           "clrstats",
 333           &ng_parse_int16_type,
 334           NULL
 335         },
 336         {
 337           NGM_PPP_COOKIE,
 338           NGM_PPP_GETCLR_LINK_STATS,
 339           "getclrstats",
 340           &ng_parse_int16_type,
 341           &ng_ppp_stats_type
 342         },
 343         { 0 }
 344 };
 345
 346 /* Node type descriptor */
 347 static struct ng_type ng_ppp_typestruct = {
 348         NG_VERSION,
 349         NG_PPP_NODE_TYPE,
 350         NULL,
 351         ng_ppp_constructor,
 352         ng_ppp_rcvmsg,
 353         ng_ppp_rmnode,
 354         ng_ppp_newhook,
 355         NULL,
 356         NULL,
 357         ng_ppp_rcvdata,
 358         ng_ppp_rcvdata,
 359         ng_ppp_disconnect,
 360         ng_ppp_cmds
 361 };
 362 NETGRAPH_INIT(ppp, &ng_ppp_typestruct);
 363
 364 static int *compareLatencies;                   /* hack for ng_ppp_intcmp() */
 365
 366 /* Address and control field header */
 367 static const u_char ng_ppp_acf[2] = { 0xff, 0x03 };
 368
 369 /* Maximum time we'll let a complete incoming packet sit in the queue */
 370 static const struct timeval ng_ppp_max_staleness = { 2, 0 };    /* 2 seconds */
 371
 372 #define ERROUT(x)       do { error = (x); goto done; } while (0)
 373
 374 /************************************************************************
 375                         NETGRAPH NODE STUFF
 376  ************************************************************************/
 377
 378 /*
 379  * Node type constructor
 380  */
 381 static int
 382 ng_ppp_constructor(node_p *nodep)
 383 {
 384         priv_p priv;
 385         int i, error;
 386
 387         /* Allocate private structure */
 388         MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
 389         if (priv == NULL)
 390                 return (ENOMEM);
 391
 392         /* Call generic node constructor */
 393         if ((error = ng_make_node_common(&ng_ppp_typestruct, nodep))) {
 394                 FREE(priv, M_NETGRAPH);
 395                 return (error);
 396         }
 397         (*nodep)->private = priv;
 398
 399         /* Initialize state */
 400         CIRCLEQ_INIT(&priv->frags);
 401         for (i = 0; i < NG_PPP_MAX_LINKS; i++)
 402                 priv->links[i].seq = MP_NOSEQ;
 403         callout_init(&priv->fragTimer);
 404
 405         /* Done */
 406         return (0);
 407 }
 408
 409 /*
 410  * Give our OK for a hook to be added
 411  */
 412 static int
 413 ng_ppp_newhook(node_p node, hook_p hook, const char *name)
 414 {
 415         const priv_p priv = node->private;
 416         int linkNum = -1;
 417         hook_p *hookPtr = NULL;
 418         int hookIndex = -1;
 419
 420         /* Figure out which hook it is */
 421         if (strncmp(name, NG_PPP_HOOK_LINK_PREFIX,      /* a link hook? */
 422             strlen(NG_PPP_HOOK_LINK_PREFIX)) == 0) {
 423                 const char *cp;
 424                 char *eptr;
 425
 426                 cp = name + strlen(NG_PPP_HOOK_LINK_PREFIX);
 427                 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 428                         return (EINVAL);
 429                 linkNum = (int)strtoul(cp, &eptr, 10);
 430                 if (*eptr != '\0' || linkNum < 0 || linkNum >= NG_PPP_MAX_LINKS)
 431                         return (EINVAL);
 432                 hookPtr = &priv->links[linkNum].hook;
 433                 hookIndex = ~linkNum;
 434         } else {                                /* must be a non-link hook */
 435                 int i;
 436
 437                 for (i = 0; ng_ppp_hook_names[i] != NULL; i++) {
 438                         if (strcmp(name, ng_ppp_hook_names[i]) == 0) {
 439                                 hookPtr = &priv->hooks[i];
 440                                 hookIndex = i;
 441                                 break;
 442                         }
 443                 }
 444                 if (ng_ppp_hook_names[i] == NULL)
 445                         return (EINVAL);        /* no such hook */
 446         }
 447
 448         /* See if hook is already connected */
 449         if (*hookPtr != NULL)
 450                 return (EISCONN);
 451
 452         /* Disallow more than one link unless multilink is enabled */
 453         if (linkNum != -1 && priv->links[linkNum].conf.enableLink
 454             && !priv->conf.enableMultilink && priv->numActiveLinks >= 1)
 455                 return (ENODEV);
 456
 457         /* OK */
 458         *hookPtr = hook;
 459         HOOK_INDEX(hook) = hookIndex;
 460         ng_ppp_update(node, 0);
 461         return (0);
 462 }
 463
 464 /*
 465  * Receive a control message
 466  */
 467 static int
 468 ng_ppp_rcvmsg(node_p node, struct ng_mesg *msg,
 469               const char *raddr, struct ng_mesg **rptr)
 470 {
 471         const priv_p priv = node->private;
 472         struct ng_mesg *resp = NULL;
 473         int error = 0;
 474
 475         switch (msg->header.typecookie) {
 476         case NGM_PPP_COOKIE:
 477                 switch (msg->header.cmd) {
 478                 case NGM_PPP_SET_CONFIG:
 479                     {
 480                         struct ng_ppp_node_conf *const conf =
 481                             (struct ng_ppp_node_conf *)msg->data;
 482                         int i;
 483
 484                         /* Check for invalid or illegal config */
 485                         if (msg->header.arglen != sizeof(*conf))
 486                                 ERROUT(EINVAL);
 487                         if (!ng_ppp_config_valid(node, conf))
 488                                 ERROUT(EINVAL);
 489
 490                         /* Copy config */
 491                         priv->conf = conf->bund;
 492                         for (i = 0; i < NG_PPP_MAX_LINKS; i++)
 493                                 priv->links[i].conf = conf->links[i];
 494                         ng_ppp_update(node, 1);
 495                         break;
 496                     }
 497                 case NGM_PPP_GET_CONFIG:
 498                     {
 499                         struct ng_ppp_node_conf *conf;
 500                         int i;
 501
 502                         NG_MKRESPONSE(resp, msg, sizeof(*conf), M_NOWAIT);
 503                         if (resp == NULL)
 504                                 ERROUT(ENOMEM);
 505                         conf = (struct ng_ppp_node_conf *)resp->data;
 506                         conf->bund = priv->conf;
 507                         for (i = 0; i < NG_PPP_MAX_LINKS; i++)
 508                                 conf->links[i] = priv->links[i].conf;
 509                         break;
 510                     }
 511                 case NGM_PPP_GET_MP_STATE:
 512                     {
 513                         struct ng_ppp_mp_state *info;
 514                         int i;
 515
 516                         NG_MKRESPONSE(resp, msg, sizeof(*info), M_NOWAIT);
 517                         if (resp == NULL)
 518                                 ERROUT(ENOMEM);
 519                         info = (struct ng_ppp_mp_state *)resp->data;
 520                         bzero(info, sizeof(*info));
 521                         for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
 522                                 if (priv->links[i].seq != MP_NOSEQ)
 523                                         info->rseq[i] = priv->links[i].seq;
 524                         }
 525                         info->mseq = priv->mseq;
 526                         info->xseq = priv->xseq;
 527                         break;
 528                     }
 529                 case NGM_PPP_GET_LINK_STATS:
 530                 case NGM_PPP_CLR_LINK_STATS:
 531                 case NGM_PPP_GETCLR_LINK_STATS:
 532                     {
 533                         struct ng_ppp_link_stat *stats;
 534                         u_int16_t linkNum;
 535
 536                         if (msg->header.arglen != sizeof(u_int16_t))
 537                                 ERROUT(EINVAL);
 538                         linkNum = *((u_int16_t *) msg->data);
 539                         if (linkNum >= NG_PPP_MAX_LINKS
 540                             && linkNum != NG_PPP_BUNDLE_LINKNUM)
 541                                 ERROUT(EINVAL);
 542                         stats = (linkNum == NG_PPP_BUNDLE_LINKNUM) ?
 543                             &priv->bundleStats : &priv->links[linkNum].stats;
 544                         if (msg->header.cmd != NGM_PPP_CLR_LINK_STATS) {
 545                                 NG_MKRESPONSE(resp, msg,
 546                                     sizeof(struct ng_ppp_link_stat), M_NOWAIT);
 547                                 if (resp == NULL)
 548                                         ERROUT(ENOMEM);
 549                                 bcopy(stats, resp->data, sizeof(*stats));
 550                         }
 551                         if (msg->header.cmd != NGM_PPP_GET_LINK_STATS)
 552                                 bzero(stats, sizeof(*stats));
 553                         break;
 554                     }
 555                 default:
 556                         error = EINVAL;
 557                         break;
 558                 }
 559                 break;
 560         case NGM_VJC_COOKIE:
 561             {
 562                 char path[NG_PATHSIZ];
 563                 node_p origNode;
 564
 565                 if ((error = ng_path2node(node, raddr, &origNode, NULL)) != 0)
 566                         ERROUT(error);
 567                 ksnprintf(path, sizeof(path), "[%lx]:%s",
 568                     (long)node, NG_PPP_HOOK_VJC_IP);
 569                 return ng_send_msg(origNode, msg, path, rptr);
 570             }
 571         default:
 572                 error = EINVAL;
 573                 break;
 574         }
 575         if (rptr)
 576                 *rptr = resp;
 577         else if (resp)
 578                 FREE(resp, M_NETGRAPH);
 579
 580 done:
 581         FREE(msg, M_NETGRAPH);
 582         return (error);
 583 }
 584
 585 /*
 586  * Receive data on a hook
 587  */
 588 static int
 589 ng_ppp_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
 590 {
 591         const node_p node = hook->node;
 592         const priv_p priv = node->private;
 593         const int index = HOOK_INDEX(hook);
 594         u_int16_t linkNum = NG_PPP_BUNDLE_LINKNUM;
 595         hook_p outHook = NULL;
 596         int proto = 0, error;
 597
 598         /* Did it come from a link hook? */
 599         if (index < 0) {
 600                 struct ng_ppp_link *link;
 601
 602                 /* Convert index into a link number */
 603                 linkNum = (u_int16_t)~index;
 604                 KASSERT(linkNum < NG_PPP_MAX_LINKS,
 605                     ("%s: bogus index 0x%x", __func__, index));
 606                 link = &priv->links[linkNum];
 607
 608                 /* Stats */
 609                 link->stats.recvFrames++;
 610                 link->stats.recvOctets += m->m_pkthdr.len;
 611
 612                 /* Strip address and control fields, if present */
 613                 if (m->m_pkthdr.len >= 2) {
 614                         if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
 615                                 NG_FREE_DATA(m, meta);
 616                                 return (ENOBUFS);
 617                         }
 618                         if (bcmp(mtod(m, u_char *), &ng_ppp_acf, 2) == 0)
 619                                 m_adj(m, 2);
 620                 }
 621
 622                 /* Dispatch incoming frame (if not enabled, to bypass) */
 623                 return ng_ppp_input(node,
 624                     !link->conf.enableLink, linkNum, m, meta);
 625         }
 626
 627         /* Get protocol & check if data allowed from this hook */
 628         switch (index) {
 629
 630         /* Outgoing data */
 631         case HOOK_INDEX_ATALK:
 632                 if (!priv->conf.enableAtalk) {
 633                         NG_FREE_DATA(m, meta);
 634                         return (ENXIO);
 635                 }
 636                 proto = PROT_APPLETALK;
 637                 break;
 638         case HOOK_INDEX_IPX:
 639                 if (!priv->conf.enableIPX) {
 640                         NG_FREE_DATA(m, meta);
 641                         return (ENXIO);
 642                 }
 643                 proto = PROT_IPX;
 644                 break;
 645         case HOOK_INDEX_IPV6:
 646                 if (!priv->conf.enableIPv6) {
 647                         NG_FREE_DATA(m, meta);
 648                         return (ENXIO);
 649                 }
 650                 proto = PROT_IPV6;
 651                 break;
 652         case HOOK_INDEX_INET:
 653         case HOOK_INDEX_VJC_VJIP:
 654                 if (!priv->conf.enableIP) {
 655                         NG_FREE_DATA(m, meta);
 656                         return (ENXIO);
 657                 }
 658                 proto = PROT_IP;
 659                 break;
 660         case HOOK_INDEX_VJC_COMP:
 661                 if (!priv->conf.enableVJCompression) {
 662                         NG_FREE_DATA(m, meta);
 663                         return (ENXIO);
 664                 }
 665                 proto = PROT_VJCOMP;
 666                 break;
 667         case HOOK_INDEX_VJC_UNCOMP:
 668                 if (!priv->conf.enableVJCompression) {
 669                         NG_FREE_DATA(m, meta);
 670                         return (ENXIO);
 671                 }
 672                 proto = PROT_VJUNCOMP;
 673                 break;
 674         case HOOK_INDEX_COMPRESS:
 675                 if (!priv->conf.enableCompression) {
 676                         NG_FREE_DATA(m, meta);
 677                         return (ENXIO);
 678                 }
 679                 proto = PROT_COMPD;
 680                 break;
 681         case HOOK_INDEX_ENCRYPT:
 682                 if (!priv->conf.enableEncryption) {
 683                         NG_FREE_DATA(m, meta);
 684                         return (ENXIO);
 685                 }
 686                 proto = PROT_CRYPTD;
 687                 break;
 688         case HOOK_INDEX_BYPASS:
 689                 if (m->m_pkthdr.len < 4) {
 690                         NG_FREE_DATA(m, meta);
 691                         return (EINVAL);
 692                 }
 693                 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
 694                         NG_FREE_META(meta);
 695                         return (ENOBUFS);
 696                 }
 697                 linkNum = ntohs(mtod(m, u_int16_t *)[0]);
 698                 proto = ntohs(mtod(m, u_int16_t *)[1]);
 699                 m_adj(m, 4);
 700                 if (linkNum >= NG_PPP_MAX_LINKS
 701                     && linkNum != NG_PPP_BUNDLE_LINKNUM) {
 702                         NG_FREE_DATA(m, meta);
 703                         return (EINVAL);
 704                 }
 705                 break;
 706
 707         /* Incoming data */
 708         case HOOK_INDEX_VJC_IP:
 709                 if (!priv->conf.enableIP || !priv->conf.enableVJDecompression) {
 710                         NG_FREE_DATA(m, meta);
 711                         return (ENXIO);
 712                 }
 713                 break;
 714         case HOOK_INDEX_DECOMPRESS:
 715                 if (!priv->conf.enableDecompression) {
 716                         NG_FREE_DATA(m, meta);
 717                         return (ENXIO);
 718                 }
 719                 break;
 720         case HOOK_INDEX_DECRYPT:
 721                 if (!priv->conf.enableDecryption) {
 722                         NG_FREE_DATA(m, meta);
 723                         return (ENXIO);
 724                 }
 725                 break;
 726         default:
 727                 panic("%s: bogus index 0x%x", __func__, index);
 728         }
 729
 730         /* Now figure out what to do with the frame */
 731         switch (index) {
 732
 733         /* Outgoing data */
 734         case HOOK_INDEX_INET:
 735                 if (priv->conf.enableVJCompression && priv->vjCompHooked) {
 736                         outHook = priv->hooks[HOOK_INDEX_VJC_IP];
 737                         break;
 738                 }
 739                 /* FALLTHROUGH */
 740         case HOOK_INDEX_ATALK:
 741         case HOOK_INDEX_IPV6:
 742         case HOOK_INDEX_IPX:
 743         case HOOK_INDEX_VJC_COMP:
 744         case HOOK_INDEX_VJC_UNCOMP:
 745         case HOOK_INDEX_VJC_VJIP:
 746                 if (priv->conf.enableCompression
 747                     && priv->hooks[HOOK_INDEX_COMPRESS] != NULL) {
 748                         if ((m = ng_ppp_addproto(m, proto, 1)) == NULL) {
 749                                 NG_FREE_META(meta);
 750                                 return (ENOBUFS);
 751                         }
 752                         outHook = priv->hooks[HOOK_INDEX_COMPRESS];
 753                         break;
 754                 }
 755                 /* FALLTHROUGH */
 756         case HOOK_INDEX_COMPRESS:
 757                 if (priv->conf.enableEncryption
 758                     && priv->hooks[HOOK_INDEX_ENCRYPT] != NULL) {
 759                         if ((m = ng_ppp_addproto(m, proto, 1)) == NULL) {
 760                                 NG_FREE_META(meta);
 761                                 return (ENOBUFS);
 762                         }
 763                         outHook = priv->hooks[HOOK_INDEX_ENCRYPT];
 764                         break;
 765                 }
 766                 /* FALLTHROUGH */
 767         case HOOK_INDEX_ENCRYPT:
 768                 return ng_ppp_output(node, 0,
 769                     proto, NG_PPP_BUNDLE_LINKNUM, m, meta);
 770
 771         case HOOK_INDEX_BYPASS:
 772                 return ng_ppp_output(node, 1, proto, linkNum, m, meta);
 773
 774         /* Incoming data */
 775         case HOOK_INDEX_DECRYPT:
 776         case HOOK_INDEX_DECOMPRESS:
 777                 return ng_ppp_input(node, 0, NG_PPP_BUNDLE_LINKNUM, m, meta);
 778
 779         case HOOK_INDEX_VJC_IP:
 780                 outHook = priv->hooks[HOOK_INDEX_INET];
 781                 break;
 782         }
 783
 784         /* Send packet out hook */
 785         NG_SEND_DATA(error, outHook, m, meta);
 786         return (error);
 787 }
 788
 789 /*
 790  * Destroy node
 791  */
 792 static int
 793 ng_ppp_rmnode(node_p node)
 794 {
 795         const priv_p priv = node->private;
 796
 797         /* Stop fragment queue timer */
 798         ng_ppp_stop_frag_timer(node);
 799
 800         /* Take down netgraph node */
 801         node->flags |= NG_INVALID;
 802         ng_cutlinks(node);
 803         ng_unname(node);
 804         ng_ppp_frag_reset(node);
 805         bzero(priv, sizeof(*priv));
 806         FREE(priv, M_NETGRAPH);
 807         node->private = NULL;
 808         ng_unref(node);         /* let the node escape */
 809         return (0);
 810 }
 811
 812 /*
 813  * Hook disconnection
 814  */
 815 static int
 816 ng_ppp_disconnect(hook_p hook)
 817 {
 818         const node_p node = hook->node;
 819         const priv_p priv = node->private;
 820         const int index = HOOK_INDEX(hook);
 821
 822         /* Zero out hook pointer */
 823         if (index < 0)
 824                 priv->links[~index].hook = NULL;
 825         else
 826                 priv->hooks[index] = NULL;
 827
 828         /* Update derived info (or go away if no hooks left) */
 829         if (node->numhooks > 0)
 830                 ng_ppp_update(node, 0);
 831         else
 832                 ng_rmnode(node);
 833         return (0);
 834 }
 835
 836 /************************************************************************
 837                         HELPER STUFF
 838  ************************************************************************/
 839
 840 /*
 841  * Handle an incoming frame.  Extract the PPP protocol number
 842  * and dispatch accordingly.
 843  */
 844 static int
 845 ng_ppp_input(node_p node, int bypass, int linkNum, struct mbuf *m, meta_p meta)
 846 {
 847         const priv_p priv = node->private;
 848         hook_p outHook = NULL;
 849         int proto, error;
 850
 851         /* Extract protocol number */
 852         for (proto = 0; !PROT_VALID(proto) && m->m_pkthdr.len > 0; ) {
 853                 if (m->m_len < 1 && (m = m_pullup(m, 1)) == NULL) {
 854                         NG_FREE_META(meta);
 855                         return (ENOBUFS);
 856                 }
 857                 proto = (proto << 8) + *mtod(m, u_char *);
 858                 m_adj(m, 1);
 859         }
 860         if (!PROT_VALID(proto)) {
 861                 if (linkNum == NG_PPP_BUNDLE_LINKNUM)
 862                         priv->bundleStats.badProtos++;
 863                 else
 864                         priv->links[linkNum].stats.badProtos++;
 865                 NG_FREE_DATA(m, meta);
 866                 return (EINVAL);
 867         }
 868
 869         /* Bypass frame? */
 870         if (bypass)
 871                 goto bypass;
 872
 873         /* Check protocol */
 874         switch (proto) {
 875         case PROT_COMPD:
 876                 if (priv->conf.enableDecompression)
 877                         outHook = priv->hooks[HOOK_INDEX_DECOMPRESS];
 878                 break;
 879         case PROT_CRYPTD:
 880                 if (priv->conf.enableDecryption)
 881                         outHook = priv->hooks[HOOK_INDEX_DECRYPT];
 882                 break;
 883         case PROT_VJCOMP:
 884                 if (priv->conf.enableVJDecompression && priv->vjCompHooked)
 885                         outHook = priv->hooks[HOOK_INDEX_VJC_COMP];
 886                 break;
 887         case PROT_VJUNCOMP:
 888                 if (priv->conf.enableVJDecompression && priv->vjCompHooked)
 889                         outHook = priv->hooks[HOOK_INDEX_VJC_UNCOMP];
 890                 break;
 891         case PROT_MP:
 892                 if (priv->conf.enableMultilink
 893                     && linkNum != NG_PPP_BUNDLE_LINKNUM)
 894                         return ng_ppp_mp_input(node, linkNum, m, meta);
 895                 break;
 896         case PROT_APPLETALK:
 897                 if (priv->conf.enableAtalk)
 898                         outHook = priv->hooks[HOOK_INDEX_ATALK];
 899                 break;
 900         case PROT_IPX:
 901                 if (priv->conf.enableIPX)
 902                         outHook = priv->hooks[HOOK_INDEX_IPX];
 903                 break;
 904         case PROT_IP:
 905                 if (priv->conf.enableIP)
 906                         outHook = priv->hooks[HOOK_INDEX_INET];
 907                 break;
 908         case PROT_IPV6:
 909                 if (priv->conf.enableIPv6)
 910                         outHook = priv->hooks[HOOK_INDEX_IPV6];
 911                 break;
 912         }
 913
 914 bypass:
 915         /* For unknown/inactive protocols, forward out the bypass hook */
 916         if (outHook == NULL) {
 917                 u_int16_t hdr[2];
 918
 919                 hdr[0] = htons(linkNum);
 920                 hdr[1] = htons((u_int16_t)proto);
 921                 if ((m = ng_ppp_prepend(m, &hdr, 4)) == NULL) {
 922                         NG_FREE_META(meta);
 923                         return (ENOBUFS);
 924                 }
 925                 outHook = priv->hooks[HOOK_INDEX_BYPASS];
 926         }
 927
 928         /* Forward frame */
 929         NG_SEND_DATA(error, outHook, m, meta);
 930         return (error);
 931 }
 932
 933 /*
 934  * Deliver a frame out a link, either a real one or NG_PPP_BUNDLE_LINKNUM.
 935  * If the link is not enabled then ENXIO is returned, unless "bypass" is != 0.
 936  *
 937  * If the frame is too big for the particular link, return EMSGSIZE.
 938  */
 939 static int
 940 ng_ppp_output(node_p node, int bypass,
 941         int proto, int linkNum, struct mbuf *m, meta_p meta)
 942 {
 943         const priv_p priv = node->private;
 944         struct ng_ppp_link *link;
 945         int len, error;
 946         u_int16_t mru;
 947
 948         /* If not doing MP, map bundle virtual link to (the only) link */
 949         if (linkNum == NG_PPP_BUNDLE_LINKNUM && !priv->conf.enableMultilink)
 950                 linkNum = priv->activeLinks[0];
 951
 952         /* Get link pointer (optimization) */
 953         link = (linkNum != NG_PPP_BUNDLE_LINKNUM) ?
 954             &priv->links[linkNum] : NULL;
 955
 956         /* Check link status (if real) */
 957         if (linkNum != NG_PPP_BUNDLE_LINKNUM) {
 958                 if (!bypass && !link->conf.enableLink) {
 959                         NG_FREE_DATA(m, meta);
 960                         return (ENXIO);
 961                 }
 962                 if (link->hook == NULL) {
 963                         NG_FREE_DATA(m, meta);
 964                         return (ENETDOWN);
 965                 }
 966         }
 967
 968         /* Check peer's MRU for this link */
 969         mru = (link != NULL) ? link->conf.mru : priv->conf.mrru;
 970         if (mru != 0 && m->m_pkthdr.len > mru) {
 971                 NG_FREE_DATA(m, meta);
 972                 return (EMSGSIZE);
 973         }
 974
 975         /* Prepend protocol number, possibly compressed */
 976         if ((m = ng_ppp_addproto(m, proto,
 977             linkNum == NG_PPP_BUNDLE_LINKNUM
 978               || link->conf.enableProtoComp)) == NULL) {
 979                 NG_FREE_META(meta);
 980                 return (ENOBUFS);
 981         }
 982
 983         /* Special handling for the MP virtual link */
 984         if (linkNum == NG_PPP_BUNDLE_LINKNUM)
 985                 return ng_ppp_mp_output(node, m, meta);
 986
 987         /* Prepend address and control field (unless compressed) */
 988         if (proto == PROT_LCP || !link->conf.enableACFComp) {
 989                 if ((m = ng_ppp_prepend(m, &ng_ppp_acf, 2)) == NULL) {
 990                         NG_FREE_META(meta);
 991                         return (ENOBUFS);
 992                 }
 993         }
 994
 995         /* Deliver frame */
 996         len = m->m_pkthdr.len;
 997         NG_SEND_DATA(error, link->hook, m, meta);
 998
 999         /* Update stats and 'bytes in queue' counter */
1000         if (error == 0) {
1001                 link->stats.xmitFrames++;
1002                 link->stats.xmitOctets += len;
1003                 link->bytesInQueue += len;
1004                 getmicrouptime(&link->lastWrite);
1005         }
1006         return error;
1007 }
1008
1009 /*
1010  * Handle an incoming multi-link fragment
1011  *
1012  * The fragment reassembly algorithm is somewhat complex. This is mainly
1013  * because we are required not to reorder the reconstructed packets, yet
1014  * fragments are only guaranteed to arrive in order on a per-link basis.
1015  * In other words, when we have a complete packet ready, but the previous
1016  * packet is still incomplete, we have to decide between delivering the
1017  * complete packet and throwing away the incomplete one, or waiting to
1018  * see if the remainder of the incomplete one arrives, at which time we
1019  * can deliver both packets, in order.
1020  *
1021  * This problem is exacerbated by "sequence number slew", which is when
1022  * the sequence numbers coming in from different links are far apart from
1023  * each other. In particular, certain unnamed equipment (*cough* Ascend)
1024  * has been seen to generate sequence number slew of up to 10 on an ISDN
1025  * 2B-channel MP link. There is nothing invalid about sequence number slew
1026  * but it makes the reasssembly process have to work harder.
1027  *
1028  * However, the peer is required to transmit fragments in order on each
1029  * link. That means if we define MSEQ as the minimum over all links of
1030  * the highest sequence number received on that link, then we can always
1031  * give up any hope of receiving a fragment with sequence number < MSEQ in
1032  * the future (all of this using 'wraparound' sequence number space).
1033  * Therefore we can always immediately throw away incomplete packets
1034  * missing fragments with sequence numbers < MSEQ.
1035  *
1036  * Here is an overview of our algorithm:
1037  *
1038  *    o Received fragments are inserted into a queue, for which we
1039  *      maintain these invariants between calls to this function:
1040  *
1041  *      - Fragments are ordered in the queue by sequence number
1042  *      - If a complete packet is at the head of the queue, then
1043  *        the first fragment in the packet has seq# > MSEQ + 1
1044  *        (otherwise, we could deliver it immediately)
1045  *      - If any fragments have seq# < MSEQ, then they are necessarily
1046  *        part of a packet whose missing seq#'s are all > MSEQ (otherwise,
1047  *        we can throw them away because they'll never be completed)
1048  *      - The queue contains at most MP_MAX_QUEUE_LEN fragments
1049  *
1050  *    o We have a periodic timer that checks the queue for the first
1051  *      complete packet that has been sitting in the queue "too long".
1052  *      When one is detected, all previous (incomplete) fragments are
1053  *      discarded, their missing fragments are declared lost and MSEQ
1054  *      is increased.
1055  *
1056  *    o If we recieve a fragment with seq# < MSEQ, we throw it away
1057  *      because we've already delcared it lost.
1058  *
1059  * This assumes linkNum != NG_PPP_BUNDLE_LINKNUM.
1060  */
1061 static int
1062 ng_ppp_mp_input(node_p node, int linkNum, struct mbuf *m, meta_p meta)
1063 {
1064         const priv_p priv = node->private;
1065         struct ng_ppp_link *const link = &priv->links[linkNum];
1066         struct ng_ppp_frag frag0, *frag = &frag0;
1067         struct ng_ppp_frag *qent;
1068         int i, diff, inserted;
1069
1070         /* Stats */
1071         priv->bundleStats.recvFrames++;
1072         priv->bundleStats.recvOctets += m->m_pkthdr.len;
1073
1074         /* Extract fragment information from MP header */
1075         if (priv->conf.recvShortSeq) {
1076                 u_int16_t shdr;
1077
1078                 if (m->m_pkthdr.len < 2) {
1079                         link->stats.runts++;
1080                         NG_FREE_DATA(m, meta);
1081                         return (EINVAL);
1082                 }
1083                 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
1084                         NG_FREE_META(meta);
1085                         return (ENOBUFS);
1086                 }
1087                 shdr = ntohs(*mtod(m, u_int16_t *));
1088                 frag->seq = MP_SHORT_EXTEND(shdr);
1089                 frag->first = (shdr & MP_SHORT_FIRST_FLAG) != 0;
1090                 frag->last = (shdr & MP_SHORT_LAST_FLAG) != 0;
1091                 diff = MP_SHORT_SEQ_DIFF(frag->seq, priv->mseq);
1092                 m_adj(m, 2);
1093         } else {
1094                 u_int32_t lhdr;
1095
1096                 if (m->m_pkthdr.len < 4) {
1097                         link->stats.runts++;
1098                         NG_FREE_DATA(m, meta);
1099                         return (EINVAL);
1100                 }
1101                 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
1102                         NG_FREE_META(meta);
1103                         return (ENOBUFS);
1104                 }
1105                 lhdr = ntohl(*mtod(m, u_int32_t *));
1106                 frag->seq = MP_LONG_EXTEND(lhdr);
1107                 frag->first = (lhdr & MP_LONG_FIRST_FLAG) != 0;
1108                 frag->last = (lhdr & MP_LONG_LAST_FLAG) != 0;
1109                 diff = MP_LONG_SEQ_DIFF(frag->seq, priv->mseq);
1110                 m_adj(m, 4);
1111         }
1112         frag->data = m;
1113         frag->meta = meta;
1114         getmicrouptime(&frag->timestamp);
1115
1116         /* If sequence number is < MSEQ, we've already declared this
1117            fragment as lost, so we have no choice now but to drop it */
1118         if (diff < 0) {
1119                 link->stats.dropFragments++;
1120                 NG_FREE_DATA(m, meta);
1121                 return (0);
1122         }
1123
1124         /* Update highest received sequence number on this link and MSEQ */
1125         priv->mseq = link->seq = frag->seq;
1126         for (i = 0; i < priv->numActiveLinks; i++) {
1127                 struct ng_ppp_link *const alink =
1128                     &priv->links[priv->activeLinks[i]];
1129
1130                 if (MP_RECV_SEQ_DIFF(priv, alink->seq, priv->mseq) < 0)
1131                         priv->mseq = alink->seq;
1132         }
1133
1134         /* Allocate a new frag struct for the queue */
1135         MALLOC(frag, struct ng_ppp_frag *, sizeof(*frag), M_NETGRAPH, M_NOWAIT);
1136         if (frag == NULL) {
1137                 NG_FREE_DATA(m, meta);
1138                 ng_ppp_frag_process(node);
1139                 return (ENOMEM);
1140         }
1141         *frag = frag0;
1142
1143         /* Add fragment to queue, which is sorted by sequence number */
1144         inserted = 0;
1145         CIRCLEQ_FOREACH_REVERSE(qent, &priv->frags, f_qent) {
1146                 diff = MP_RECV_SEQ_DIFF(priv, frag->seq, qent->seq);
1147                 if (diff > 0) {
1148                         CIRCLEQ_INSERT_AFTER(&priv->frags, qent, frag, f_qent);
1149                         inserted = 1;
1150                         break;
1151                 } else if (diff == 0) {      /* should never happen! */
1152                         link->stats.dupFragments++;
1153                         NG_FREE_DATA(frag->data, frag->meta);
1154                         FREE(frag, M_NETGRAPH);
1155                         return (EINVAL);
1156                 }
1157         }
1158         if (!inserted)
1159                 CIRCLEQ_INSERT_HEAD(&priv->frags, frag, f_qent);
1160         priv->qlen++;
1161
1162         /* Process the queue */
1163         return ng_ppp_frag_process(node);
1164 }
1165
1166 /*
1167  * Examine our list of fragments, and determine if there is a
1168  * complete and deliverable packet at the head of the list.
1169  * Return 1 if so, zero otherwise.
1170  */
1171 static int
1172 ng_ppp_check_packet(node_p node)
1173 {
1174         const priv_p priv = node->private;
1175         struct ng_ppp_frag *qent, *qnext;
1176
1177         /* Check for empty queue */
1178         if (CIRCLEQ_EMPTY(&priv->frags))
1179                 return (0);
1180
1181         /* Check first fragment is the start of a deliverable packet */
1182         qent = CIRCLEQ_FIRST(&priv->frags);
1183         if (!qent->first || MP_RECV_SEQ_DIFF(priv, qent->seq, priv->mseq) > 1)
1184                 return (0);
1185
1186         /* Check that all the fragments are there */
1187         while (!qent->last) {
1188                 qnext = CIRCLEQ_NEXT(qent, f_qent);
1189                 if (qnext == (void *)&priv->frags)      /* end of queue */
1190                         return (0);
1191                 if (qnext->seq != MP_NEXT_RECV_SEQ(priv, qent->seq))
1192                         return (0);
1193                 qent = qnext;
1194         }
1195
1196         /* Got one */
1197         return (1);
1198 }
1199
1200 /*
1201  * Pull a completed packet off the head of the incoming fragment queue.
1202  * This assumes there is a completed packet there to pull off.
1203  */
1204 static void
1205 ng_ppp_get_packet(node_p node, struct mbuf **mp, meta_p *metap)
1206 {
1207         const priv_p priv = node->private;
1208         struct ng_ppp_frag *qent, *qnext;
1209         struct mbuf *m = NULL, *tail;
1210
1211         qent = CIRCLEQ_FIRST(&priv->frags);
1212         KASSERT(!CIRCLEQ_EMPTY(&priv->frags) && qent->first,
1213             ("%s: no packet", __func__));
1214         for (tail = NULL; qent != NULL; qent = qnext) {
1215                 qnext = CIRCLEQ_NEXT(qent, f_qent);
1216                 KASSERT(!CIRCLEQ_EMPTY(&priv->frags),
1217                     ("%s: empty q", __func__));
1218                 CIRCLEQ_REMOVE(&priv->frags, qent, f_qent);
1219                 if (tail == NULL) {
1220                         tail = m = qent->data;
1221                         *metap = qent->meta;    /* inherit first frag's meta */
1222                 } else {
1223                         m->m_pkthdr.len += qent->data->m_pkthdr.len;
1224                         tail->m_next = qent->data;
1225                         NG_FREE_META(qent->meta); /* drop other frags' metas */
1226                 }
1227                 while (tail->m_next != NULL)
1228                         tail = tail->m_next;
1229                 if (qent->last)
1230                         qnext = NULL;
1231                 FREE(qent, M_NETGRAPH);
1232                 priv->qlen--;
1233         }
1234         *mp = m;
1235 }
1236
1237 /*
1238  * Trim fragments from the queue whose packets can never be completed.
1239  * This assumes a complete packet is NOT at the beginning of the queue.
1240  * Returns 1 if fragments were removed, zero otherwise.
1241  */
1242 static int
1243 ng_ppp_frag_trim(node_p node)
1244 {
1245         const priv_p priv = node->private;
1246         struct ng_ppp_frag *qent, *qnext = NULL;
1247         int removed = 0;
1248
1249         /* Scan for "dead" fragments and remove them */
1250         while (1) {
1251                 int dead = 0;
1252
1253                 /* If queue is empty, we're done */
1254                 if (CIRCLEQ_EMPTY(&priv->frags))
1255                         break;
1256
1257                 /* Determine whether first fragment can ever be completed */
1258                 CIRCLEQ_FOREACH(qent, &priv->frags, f_qent) {
1259                         if (MP_RECV_SEQ_DIFF(priv, qent->seq, priv->mseq) >= 0)
1260                                 break;
1261                         qnext = CIRCLEQ_NEXT(qent, f_qent);
1262                         KASSERT(qnext != (void*)&priv->frags,
1263                             ("%s: last frag < MSEQ?", __func__));
1264                         if (qnext->seq != MP_NEXT_RECV_SEQ(priv, qent->seq)
1265                             || qent->last || qnext->first) {
1266                                 dead = 1;
1267                                 break;
1268                         }
1269                 }
1270                 if (!dead)
1271                         break;
1272
1273                 /* Remove fragment and all others in the same packet */
1274                 while ((qent = CIRCLEQ_FIRST(&priv->frags)) != qnext) {
1275                         KASSERT(!CIRCLEQ_EMPTY(&priv->frags),
1276                             ("%s: empty q", __func__));
1277                         priv->bundleStats.dropFragments++;
1278                         CIRCLEQ_REMOVE(&priv->frags, qent, f_qent);
1279                         NG_FREE_DATA(qent->data, qent->meta);
1280                         FREE(qent, M_NETGRAPH);
1281                         priv->qlen--;
1282                         removed = 1;
1283                 }
1284         }
1285         return (removed);
1286 }
1287
1288 /*
1289  * Run the queue, restoring the queue invariants
1290  */
1291 static int
1292 ng_ppp_frag_process(node_p node)
1293 {
1294         const priv_p priv = node->private;
1295         struct mbuf *m;
1296         meta_p meta;
1297
1298         /* Deliver any deliverable packets */
1299         while (ng_ppp_check_packet(node)) {
1300                 ng_ppp_get_packet(node, &m, &meta);
1301                 ng_ppp_input(node, 0, NG_PPP_BUNDLE_LINKNUM, m, meta);
1302         }
1303
1304         /* Delete dead fragments and try again */
1305         if (ng_ppp_frag_trim(node)) {
1306                 while (ng_ppp_check_packet(node)) {
1307                         ng_ppp_get_packet(node, &m, &meta);
1308                         ng_ppp_input(node, 0, NG_PPP_BUNDLE_LINKNUM, m, meta);
1309                 }
1310         }
1311
1312         /* Check for stale fragments while we're here */
1313         ng_ppp_frag_checkstale(node);
1314
1315         /* Check queue length */
1316         if (priv->qlen > MP_MAX_QUEUE_LEN) {
1317                 struct ng_ppp_frag *qent;
1318                 int i;
1319
1320                 /* Get oldest fragment */
1321                 KASSERT(!CIRCLEQ_EMPTY(&priv->frags),
1322                     ("%s: empty q", __func__));
1323                 qent = CIRCLEQ_FIRST(&priv->frags);
1324
1325                 /* Bump MSEQ if necessary */
1326                 if (MP_RECV_SEQ_DIFF(priv, priv->mseq, qent->seq) < 0) {
1327                         priv->mseq = qent->seq;
1328                         for (i = 0; i < priv->numActiveLinks; i++) {
1329                                 struct ng_ppp_link *const alink =
1330                                     &priv->links[priv->activeLinks[i]];
1331
1332                                 if (MP_RECV_SEQ_DIFF(priv,
1333                                     alink->seq, priv->mseq) < 0)
1334                                         alink->seq = priv->mseq;
1335                         }
1336                 }
1337
1338                 /* Drop it */
1339                 priv->bundleStats.dropFragments++;
1340                 CIRCLEQ_REMOVE(&priv->frags, qent, f_qent);
1341                 NG_FREE_DATA(qent->data, qent->meta);
1342                 FREE(qent, M_NETGRAPH);
1343                 priv->qlen--;
1344
1345                 /* Process queue again */
1346                 return ng_ppp_frag_process(node);
1347         }
1348
1349         /* Done */
1350         return (0);
1351 }
1352
1353 /*
1354  * Check for 'stale' completed packets that need to be delivered
1355  *
1356  * If a link goes down or has a temporary failure, MSEQ can get
1357  * "stuck", because no new incoming fragments appear on that link.
1358  * This can cause completed packets to never get delivered if
1359  * their sequence numbers are all > MSEQ + 1.
1360  *
1361  * This routine checks how long all of the completed packets have
1362  * been sitting in the queue, and if too long, removes fragments
1363  * from the queue and increments MSEQ to allow them to be delivered.
1364  */
1365 static void
1366 ng_ppp_frag_checkstale(node_p node)
1367 {
1368         const priv_p priv = node->private;
1369         struct ng_ppp_frag *qent, *beg, *end;
1370         struct timeval now, age;
1371         struct mbuf *m;
1372         meta_p meta;
1373         int i, seq;
1374         int endseq;
1375
1376         now.tv_sec = 0;                 /* uninitialized state */
1377         while (1) {
1378
1379                 /* If queue is empty, we're done */
1380                 if (CIRCLEQ_EMPTY(&priv->frags))
1381                         break;
1382
1383                 /* Find the first complete packet in the queue */
1384                 beg = end = NULL;
1385                 seq = CIRCLEQ_FIRST(&priv->frags)->seq;
1386                 CIRCLEQ_FOREACH(qent, &priv->frags, f_qent) {
1387                         if (qent->first)
1388                                 beg = qent;
1389                         else if (qent->seq != seq)
1390                                 beg = NULL;
1391                         if (beg != NULL && qent->last) {
1392                                 end = qent;
1393                                 break;
1394                         }
1395                         seq = MP_NEXT_RECV_SEQ(priv, seq);
1396                 }
1397
1398                 /* If none found, exit */
1399                 if (end == NULL)
1400                         break;
1401
1402                 /* Get current time (we assume we've been up for >= 1 second) */
1403                 if (now.tv_sec == 0)
1404                         getmicrouptime(&now);
1405
1406                 /* Check if packet has been queued too long */
1407                 age = now;
1408                 timevalsub(&age, &beg->timestamp);
1409                 if (timevalcmp(&age, &ng_ppp_max_staleness, < ))
1410                         break;
1411
1412                 /* Throw away junk fragments in front of the completed packet */
1413                 while ((qent = CIRCLEQ_FIRST(&priv->frags)) != beg) {
1414                         KASSERT(!CIRCLEQ_EMPTY(&priv->frags),
1415                             ("%s: empty q", __func__));
1416                         priv->bundleStats.dropFragments++;
1417                         CIRCLEQ_REMOVE(&priv->frags, qent, f_qent);
1418                         NG_FREE_DATA(qent->data, qent->meta);
1419                         FREE(qent, M_NETGRAPH);
1420                         priv->qlen--;
1421                 }
1422
1423                 /* Extract completed packet */
1424                 endseq = end->seq;
1425                 ng_ppp_get_packet(node, &m, &meta);
1426
1427                 /* Bump MSEQ if necessary */
1428                 if (MP_RECV_SEQ_DIFF(priv, priv->mseq, endseq) < 0) {
1429                         priv->mseq = endseq;
1430                         for (i = 0; i < priv->numActiveLinks; i++) {
1431                                 struct ng_ppp_link *const alink =
1432                                     &priv->links[priv->activeLinks[i]];
1433
1434                                 if (MP_RECV_SEQ_DIFF(priv,
1435                                     alink->seq, priv->mseq) < 0)
1436                                         alink->seq = priv->mseq;
1437                         }
1438                 }
1439
1440                 /* Deliver packet */
1441                 ng_ppp_input(node, 0, NG_PPP_BUNDLE_LINKNUM, m, meta);
1442         }
1443 }
1444
1445 /*
1446  * Periodically call ng_ppp_frag_checkstale()
1447  */
1448 static void
1449 ng_ppp_frag_timeout(void *arg)
1450 {
1451         const node_p node = arg;
1452         const priv_p priv = node->private;
1453
1454         crit_enter();
1455         /* Handle the race where shutdown happens just before splnet() above */
1456         if ((node->flags & NG_INVALID) != 0) {
1457                 ng_unref(node);
1458                 crit_exit();
1459                 return;
1460         }
1461
1462         /* Reset timer state after timeout */
1463         KASSERT(priv->timerActive, ("%s: !timerActive", __func__));
1464         priv->timerActive = 0;
1465         KASSERT(node->refs > 1, ("%s: refs=%d", __func__, node->refs));
1466         ng_unref(node);
1467
1468         /* Start timer again */
1469         ng_ppp_start_frag_timer(node);
1470
1471         /* Scan the fragment queue */
1472         ng_ppp_frag_checkstale(node);
1473         crit_exit();
1474 }
1475
1476 /*
1477  * Deliver a frame out on the bundle, i.e., figure out how to fragment
1478  * the frame across the individual PPP links and do so.
1479  */
1480 static int
1481 ng_ppp_mp_output(node_p node, struct mbuf *m, meta_p meta)
1482 {
1483         const priv_p priv = node->private;
1484         const int hdr_len = priv->conf.xmitShortSeq ? 2 : 4;
1485         int distrib[NG_PPP_MAX_LINKS];
1486         int firstFragment;
1487         int activeLinkNum;
1488
1489         /* At least one link must be active */
1490         if (priv->numActiveLinks == 0) {
1491                 NG_FREE_DATA(m, meta);
1492                 return (ENETDOWN);
1493         }
1494
1495         /* Round-robin strategy */
1496         if (priv->conf.enableRoundRobin || m->m_pkthdr.len < MP_MIN_FRAG_LEN) {
1497                 activeLinkNum = priv->lastLink++ % priv->numActiveLinks;
1498                 bzero(&distrib, priv->numActiveLinks * sizeof(distrib[0]));
1499                 distrib[activeLinkNum] = m->m_pkthdr.len;
1500                 goto deliver;
1501         }
1502
1503         /* Strategy when all links are equivalent (optimize the common case) */
1504         if (priv->allLinksEqual) {
1505                 const int fraction = m->m_pkthdr.len / priv->numActiveLinks;
1506                 int i, remain;
1507
1508                 for (i = 0; i < priv->numActiveLinks; i++)
1509                         distrib[priv->lastLink++ % priv->numActiveLinks]
1510                             = fraction;
1511                 remain = m->m_pkthdr.len - (fraction * priv->numActiveLinks);
1512                 while (remain > 0) {
1513                         distrib[priv->lastLink++ % priv->numActiveLinks]++;
1514                         remain--;
1515                 }
1516                 goto deliver;
1517         }
1518
1519         /* Strategy when all links are not equivalent */
1520         ng_ppp_mp_strategy(node, m->m_pkthdr.len, distrib);
1521
1522 deliver:
1523         /* Update stats */
1524         priv->bundleStats.xmitFrames++;
1525         priv->bundleStats.xmitOctets += m->m_pkthdr.len;
1526
1527         /* Send alloted portions of frame out on the link(s) */
1528         for (firstFragment = 1, activeLinkNum = priv->numActiveLinks - 1;
1529             activeLinkNum >= 0; activeLinkNum--) {
1530                 const int linkNum = priv->activeLinks[activeLinkNum];
1531                 struct ng_ppp_link *const link = &priv->links[linkNum];
1532
1533                 /* Deliver fragment(s) out the next link */
1534                 for ( ; distrib[activeLinkNum] > 0; firstFragment = 0) {
1535                         int len, lastFragment, error;
1536                         struct mbuf *m2;
1537                         meta_p meta2;
1538
1539                         /* Calculate fragment length; don't exceed link MTU */
1540                         len = distrib[activeLinkNum];
1541                         if (len > link->conf.mru - hdr_len)
1542                                 len = link->conf.mru - hdr_len;
1543                         distrib[activeLinkNum] -= len;
1544                         lastFragment = (len == m->m_pkthdr.len);
1545
1546                         /* Split off next fragment as "m2" */
1547                         m2 = m;
1548                         if (!lastFragment) {
1549                                 struct mbuf *n = m_split(m, len, MB_DONTWAIT);
1550
1551                                 if (n == NULL) {
1552                                         NG_FREE_DATA(m, meta);
1553                                         return (ENOMEM);
1554                                 }
1555                                 m = n;
1556                         }
1557
1558                         /* Prepend MP header */
1559                         if (priv->conf.xmitShortSeq) {
1560                                 u_int16_t shdr;
1561
1562                                 shdr = priv->xseq;
1563                                 priv->xseq =
1564                                     (priv->xseq + 1) & MP_SHORT_SEQ_MASK;
1565                                 if (firstFragment)
1566                                         shdr |= MP_SHORT_FIRST_FLAG;
1567                                 if (lastFragment)
1568                                         shdr |= MP_SHORT_LAST_FLAG;
1569                                 shdr = htons(shdr);
1570                                 m2 = ng_ppp_prepend(m2, &shdr, 2);
1571                         } else {
1572                                 u_int32_t lhdr;
1573
1574                                 lhdr = priv->xseq;
1575                                 priv->xseq =
1576                                     (priv->xseq + 1) & MP_LONG_SEQ_MASK;
1577                                 if (firstFragment)
1578                                         lhdr |= MP_LONG_FIRST_FLAG;
1579                                 if (lastFragment)
1580                                         lhdr |= MP_LONG_LAST_FLAG;
1581                                 lhdr = htonl(lhdr);
1582                                 m2 = ng_ppp_prepend(m2, &lhdr, 4);
1583                         }
1584                         if (m2 == NULL) {
1585                                 if (!lastFragment)
1586                                         m_freem(m);
1587                                 NG_FREE_META(meta);
1588                                 return (ENOBUFS);
1589                         }
1590
1591                         /* Copy the meta information, if any */
1592                         meta2 = lastFragment ? meta : ng_copy_meta(meta);
1593
1594                         /* Send fragment */
1595                         error = ng_ppp_output(node, 0,
1596                             PROT_MP, linkNum, m2, meta2);
1597                         if (error != 0) {
1598                                 if (!lastFragment)
1599                                         NG_FREE_DATA(m, meta);
1600                                 return (error);
1601                         }
1602                 }
1603         }
1604
1605         /* Done */
1606         return (0);
1607 }
1608
1609 /*
1610  * Computing the optimal fragmentation
1611  * -----------------------------------
1612  *
1613  * This routine tries to compute the optimal fragmentation pattern based
1614  * on each link's latency, bandwidth, and calculated additional latency.
1615  * The latter quantity is the additional latency caused by previously
1616  * written data that has not been transmitted yet.
1617  *
1618  * This algorithm is only useful when not all of the links have the
1619  * same latency and bandwidth values.
1620  *
1621  * The essential idea is to make the last bit of each fragment of the
1622  * frame arrive at the opposite end at the exact same time. This greedy
1623  * algorithm is optimal, in that no other scheduling could result in any
1624  * packet arriving any sooner unless packets are delivered out of order.
1625  *
1626  * Suppose link i has bandwidth b_i (in tens of bytes per milisecond) and
1627  * latency l_i (in miliseconds). Consider the function function f_i(t)
1628  * which is equal to the number of bytes that will have arrived at
1629  * the peer after t miliseconds if we start writing continuously at
1630  * time t = 0. Then f_i(t) = b_i * (t - l_i) = ((b_i * t) - (l_i * b_i).
1631  * That is, f_i(t) is a line with slope b_i and y-intersect -(l_i * b_i).
1632  * Note that the y-intersect is always <= zero because latency can't be
1633  * negative.  Note also that really the function is f_i(t) except when
1634  * f_i(t) is negative, in which case the function is zero.  To take
1635  * care of this, let Q_i(t) = { if (f_i(t) > 0) return 1; else return 0; }.
1636  * So the actual number of bytes that will have arrived at the peer after
1637  * t miliseconds is f_i(t) * Q_i(t).
1638  *
1639  * At any given time, each link has some additional latency a_i >= 0
1640  * due to previously written fragment(s) which are still in the queue.
1641  * This value is easily computed from the time since last transmission,
1642  * the previous latency value, the number of bytes written, and the
1643  * link's bandwidth.
1644  *
1645  * Assume that l_i includes any a_i already, and that the links are
1646  * sorted by latency, so that l_i <= l_{i+1}.
1647  *
1648  * Let N be the total number of bytes in the current frame we are sending.
1649  *
1650  * Suppose we were to start writing bytes at time t = 0 on all links
1651  * simultaneously, which is the most we can possibly do.  Then let
1652  * F(t) be equal to the total number of bytes received by the peer
1653  * after t miliseconds. Then F(t) = Sum_i (f_i(t) * Q_i(t)).
1654  *
1655  * Our goal is simply this: fragment the frame across the links such
1656  * that the peer is able to reconstruct the completed frame as soon as
1657  * possible, i.e., at the least possible value of t. Call this value t_0.
1658  *
1659  * Then it follows that F(t_0) = N. Our strategy is first to find the value
1660  * of t_0, and then deduce how many bytes to write to each link.
1661  *
1662  * Rewriting F(t_0):
1663  *
1664  *   t_0 = ( N + Sum_i ( l_i * b_i * Q_i(t_0) ) ) / Sum_i ( b_i * Q_i(t_0) )
1665  *
1666  * Now, we note that Q_i(t) is constant for l_i <= t <= l_{i+1}. t_0 will
1667  * lie in one of these ranges.  To find it, we just need to find the i such
1668  * that F(l_i) <= N <= F(l_{i+1}).  Then we compute all the constant values
1669  * for Q_i() in this range, plug in the remaining values, solving for t_0.
1670  *
1671  * Once t_0 is known, then the number of bytes to send on link i is
1672  * just f_i(t_0) * Q_i(t_0).
1673  *
1674  * In other words, we start allocating bytes to the links one at a time.
1675  * We keep adding links until the frame is completely sent.  Some links
1676  * may not get any bytes because their latency is too high.
1677  *
1678  * Is all this work really worth the trouble?  Depends on the situation.
1679  * The bigger the ratio of computer speed to link speed, and the more
1680  * important total bundle latency is (e.g., for interactive response time),
1681  * the more it's worth it.  There is however the cost of calling this
1682  * function for every frame.  The running time is O(n^2) where n is the
1683  * number of links that receive a non-zero number of bytes.
1684  *
1685  * Since latency is measured in miliseconds, the "resolution" of this
1686  * algorithm is one milisecond.
1687  *
1688  * To avoid this algorithm altogether, configure all links to have the
1689  * same latency and bandwidth.
1690  */
1691 static void
1692 ng_ppp_mp_strategy(node_p node, int len, int *distrib)
1693 {
1694         const priv_p priv = node->private;
1695         int latency[NG_PPP_MAX_LINKS];
1696         int sortByLatency[NG_PPP_MAX_LINKS];
1697         int activeLinkNum;
1698         int t0, total, topSum, botSum;
1699         struct timeval now;
1700         int i, numFragments;
1701
1702         /* If only one link, this gets real easy */
1703         if (priv->numActiveLinks == 1) {
1704                 distrib[0] = len;
1705                 return;
1706         }
1707
1708         /* Get current time */
1709         getmicrouptime(&now);
1710
1711         /* Compute latencies for each link at this point in time */
1712         for (activeLinkNum = 0;
1713             activeLinkNum < priv->numActiveLinks; activeLinkNum++) {
1714                 struct ng_ppp_link *alink;
1715                 struct timeval diff;
1716                 int xmitBytes;
1717
1718                 /* Start with base latency value */
1719                 alink = &priv->links[priv->activeLinks[activeLinkNum]];
1720                 latency[activeLinkNum] = alink->conf.latency;
1721                 sortByLatency[activeLinkNum] = activeLinkNum;   /* see below */
1722
1723                 /* Any additional latency? */
1724                 if (alink->bytesInQueue == 0)
1725                         continue;
1726
1727                 /* Compute time delta since last write */
1728                 diff = now;
1729                 timevalsub(&diff, &alink->lastWrite);
1730                 if (now.tv_sec < 0 || diff.tv_sec >= 10) {      /* sanity */
1731                         alink->bytesInQueue = 0;
1732                         continue;
1733                 }
1734
1735                 /* How many bytes could have transmitted since last write? */
1736                 xmitBytes = (alink->conf.bandwidth * diff.tv_sec)
1737                     + (alink->conf.bandwidth * (diff.tv_usec / 1000)) / 100;
1738                 alink->bytesInQueue -= xmitBytes;
1739                 if (alink->bytesInQueue < 0)
1740                         alink->bytesInQueue = 0;
1741                 else
1742                         latency[activeLinkNum] +=
1743                             (100 * alink->bytesInQueue) / alink->conf.bandwidth;
1744         }
1745
1746         /* Sort active links by latency */
1747         compareLatencies = latency;
1748         kqsort(sortByLatency,
1749             priv->numActiveLinks, sizeof(*sortByLatency), ng_ppp_intcmp);
1750         compareLatencies = NULL;
1751
1752         /* Find the interval we need (add links in sortByLatency[] order) */
1753         for (numFragments = 1;
1754             numFragments < priv->numActiveLinks; numFragments++) {
1755                 for (total = i = 0; i < numFragments; i++) {
1756                         int flowTime;
1757
1758                         flowTime = latency[sortByLatency[numFragments]]
1759                             - latency[sortByLatency[i]];
1760                         total += ((flowTime * priv->links[
1761                             priv->activeLinks[sortByLatency[i]]].conf.bandwidth)
1762                                 + 99) / 100;
1763                 }
1764                 if (total >= len)
1765                         break;
1766         }
1767
1768         /* Solve for t_0 in that interval */
1769         for (topSum = botSum = i = 0; i < numFragments; i++) {
1770                 int bw = priv->links[
1771                     priv->activeLinks[sortByLatency[i]]].conf.bandwidth;
1772
1773                 topSum += latency[sortByLatency[i]] * bw;       /* / 100 */
1774                 botSum += bw;                                   /* / 100 */
1775         }
1776         t0 = ((len * 100) + topSum + botSum / 2) / botSum;
1777
1778         /* Compute f_i(t_0) all i */
1779         bzero(distrib, priv->numActiveLinks * sizeof(*distrib));
1780         for (total = i = 0; i < numFragments; i++) {
1781                 int bw = priv->links[
1782                     priv->activeLinks[sortByLatency[i]]].conf.bandwidth;
1783
1784                 distrib[sortByLatency[i]] =
1785                     (bw * (t0 - latency[sortByLatency[i]]) + 50) / 100;
1786                 total += distrib[sortByLatency[i]];
1787         }
1788
1789         /* Deal with any rounding error */
1790         if (total < len) {
1791                 struct ng_ppp_link *fastLink =
1792                     &priv->links[priv->activeLinks[sortByLatency[0]]];
1793                 int fast = 0;
1794
1795                 /* Find the fastest link */
1796                 for (i = 1; i < numFragments; i++) {
1797                         struct ng_ppp_link *const link =
1798                             &priv->links[priv->activeLinks[sortByLatency[i]]];
1799
1800                         if (link->conf.bandwidth > fastLink->conf.bandwidth) {
1801                                 fast = i;
1802                                 fastLink = link;
1803                         }
1804                 }
1805                 distrib[sortByLatency[fast]] += len - total;
1806         } else while (total > len) {
1807                 struct ng_ppp_link *slowLink =
1808                     &priv->links[priv->activeLinks[sortByLatency[0]]];
1809                 int delta, slow = 0;
1810
1811                 /* Find the slowest link that still has bytes to remove */
1812                 for (i = 1; i < numFragments; i++) {
1813                         struct ng_ppp_link *const link =
1814                             &priv->links[priv->activeLinks[sortByLatency[i]]];
1815
1816                         if (distrib[sortByLatency[slow]] == 0
1817                           || (distrib[sortByLatency[i]] > 0
1818                             && link->conf.bandwidth <
1819                               slowLink->conf.bandwidth)) {
1820                                 slow = i;
1821                                 slowLink = link;
1822                         }
1823                 }
1824                 delta = total - len;
1825                 if (delta > distrib[sortByLatency[slow]])
1826                         delta = distrib[sortByLatency[slow]];
1827                 distrib[sortByLatency[slow]] -= delta;
1828                 total -= delta;
1829         }
1830 }
1831
1832 /*
1833  * Compare two integers
1834  */
1835 static int
1836 ng_ppp_intcmp(const void *v1, const void *v2)
1837 {
1838         const int index1 = *((const int *) v1);
1839         const int index2 = *((const int *) v2);
1840
1841         return compareLatencies[index1] - compareLatencies[index2];
1842 }
1843
1844 /*
1845  * Prepend a possibly compressed PPP protocol number in front of a frame
1846  */
1847 static struct mbuf *
1848 ng_ppp_addproto(struct mbuf *m, int proto, int compOK)
1849 {
1850         if (compOK && PROT_COMPRESSABLE(proto)) {
1851                 u_char pbyte = (u_char)proto;
1852
1853                 return ng_ppp_prepend(m, &pbyte, 1);
1854         } else {
1855                 u_int16_t pword = htons((u_int16_t)proto);
1856
1857                 return ng_ppp_prepend(m, &pword, 2);
1858         }
1859 }
1860
1861 /*
1862  * Prepend some bytes to an mbuf
1863  */
1864 static struct mbuf *
1865 ng_ppp_prepend(struct mbuf *m, const void *buf, int len)
1866 {
1867         M_PREPEND(m, len, MB_DONTWAIT);
1868         if (m == NULL || (m->m_len < len && (m = m_pullup(m, len)) == NULL))
1869                 return (NULL);
1870         bcopy(buf, mtod(m, u_char *), len);
1871         return (m);
1872 }
1873
1874 /*
1875  * Update private information that is derived from other private information
1876  */
1877 static void
1878 ng_ppp_update(node_p node, int newConf)
1879 {
1880         const priv_p priv = node->private;
1881         int i;
1882
1883         /* Update active status for VJ Compression */
1884         priv->vjCompHooked = priv->hooks[HOOK_INDEX_VJC_IP] != NULL
1885             && priv->hooks[HOOK_INDEX_VJC_COMP] != NULL
1886             && priv->hooks[HOOK_INDEX_VJC_UNCOMP] != NULL
1887             && priv->hooks[HOOK_INDEX_VJC_VJIP] != NULL;
1888
1889         /* Increase latency for each link an amount equal to one MP header */
1890         if (newConf) {
1891                 for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
1892                         int hdrBytes;
1893
1894                         hdrBytes = (priv->links[i].conf.enableACFComp ? 0 : 2)
1895                             + (priv->links[i].conf.enableProtoComp ? 1 : 2)
1896                             + (priv->conf.xmitShortSeq ? 2 : 4);
1897                         priv->links[i].conf.latency +=
1898                             ((hdrBytes * priv->links[i].conf.bandwidth) + 50)
1899                                 / 100;
1900                 }
1901         }
1902
1903         /* Update list of active links */
1904         bzero(&priv->activeLinks, sizeof(priv->activeLinks));
1905         priv->numActiveLinks = 0;
1906         priv->allLinksEqual = 1;
1907         for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
1908                 struct ng_ppp_link *const link = &priv->links[i];
1909
1910                 /* Is link active? */
1911                 if (link->conf.enableLink && link->hook != NULL) {
1912                         struct ng_ppp_link *link0;
1913
1914                         /* Add link to list of active links */
1915                         priv->activeLinks[priv->numActiveLinks++] = i;
1916                         link0 = &priv->links[priv->activeLinks[0]];
1917
1918                         /* Determine if all links are still equal */
1919                         if (link->conf.latency != link0->conf.latency
1920                           || link->conf.bandwidth != link0->conf.bandwidth)
1921                                 priv->allLinksEqual = 0;
1922
1923                         /* Initialize rec'd sequence number */
1924                         if (link->seq == MP_NOSEQ) {
1925                                 link->seq = (link == link0) ?
1926                                     MP_INITIAL_SEQ : link0->seq;
1927                         }
1928                 } else
1929                         link->seq = MP_NOSEQ;
1930         }
1931
1932         /* Update MP state as multi-link is active or not */
1933         if (priv->conf.enableMultilink && priv->numActiveLinks > 0)
1934                 ng_ppp_start_frag_timer(node);
1935         else {
1936                 ng_ppp_stop_frag_timer(node);
1937                 ng_ppp_frag_reset(node);
1938                 priv->xseq = MP_INITIAL_SEQ;
1939                 priv->mseq = MP_INITIAL_SEQ;
1940                 for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
1941                         struct ng_ppp_link *const link = &priv->links[i];
1942
1943                         bzero(&link->lastWrite, sizeof(link->lastWrite));
1944                         link->bytesInQueue = 0;
1945                         link->seq = MP_NOSEQ;
1946                 }
1947         }
1948 }
1949
1950 /*
1951  * Determine if a new configuration would represent a valid change
1952  * from the current configuration and link activity status.
1953  */
1954 static int
1955 ng_ppp_config_valid(node_p node, const struct ng_ppp_node_conf *newConf)
1956 {
1957         const priv_p priv = node->private;
1958         int i, newNumLinksActive;
1959
1960         /* Check per-link config and count how many links would be active */
1961         for (newNumLinksActive = i = 0; i < NG_PPP_MAX_LINKS; i++) {
1962                 if (newConf->links[i].enableLink && priv->links[i].hook != NULL)
1963                         newNumLinksActive++;
1964                 if (!newConf->links[i].enableLink)
1965                         continue;
1966                 if (newConf->links[i].mru < MP_MIN_LINK_MRU)
1967                         return (0);
1968                 if (newConf->links[i].bandwidth == 0)
1969                         return (0);
1970                 if (newConf->links[i].bandwidth > NG_PPP_MAX_BANDWIDTH)
1971                         return (0);
1972                 if (newConf->links[i].latency > NG_PPP_MAX_LATENCY)
1973                         return (0);
1974         }
1975
1976         /* Check bundle parameters */
1977         if (newConf->bund.enableMultilink && newConf->bund.mrru < MP_MIN_MRRU)
1978                 return (0);
1979
1980         /* Disallow changes to multi-link configuration while MP is active */
1981         if (priv->numActiveLinks > 0 && newNumLinksActive > 0) {
1982                 if (!priv->conf.enableMultilink
1983                                 != !newConf->bund.enableMultilink
1984                     || !priv->conf.xmitShortSeq != !newConf->bund.xmitShortSeq
1985                     || !priv->conf.recvShortSeq != !newConf->bund.recvShortSeq)
1986                         return (0);
1987         }
1988
1989         /* At most one link can be active unless multi-link is enabled */
1990         if (!newConf->bund.enableMultilink && newNumLinksActive > 1)
1991                 return (0);
1992
1993         /* Configuration change would be valid */
1994         return (1);
1995 }
1996
1997 /*
1998  * Free all entries in the fragment queue
1999  */
2000 static void
2001 ng_ppp_frag_reset(node_p node)
2002 {
2003         const priv_p priv = node->private;
2004         struct ng_ppp_frag *qent, *qnext;
2005
2006         for (qent = CIRCLEQ_FIRST(&priv->frags);
2007             qent != (void *)&priv->frags; qent = qnext) {
2008                 qnext = CIRCLEQ_NEXT(qent, f_qent);
2009                 NG_FREE_DATA(qent->data, qent->meta);
2010                 FREE(qent, M_NETGRAPH);
2011         }
2012         CIRCLEQ_INIT(&priv->frags);
2013         priv->qlen = 0;
2014 }
2015
2016 /*
2017  * Start fragment queue timer
2018  */
2019 static void
2020 ng_ppp_start_frag_timer(node_p node)
2021 {
2022         const priv_p priv = node->private;
2023
2024         if (!priv->timerActive) {
2025                 callout_reset(&priv->fragTimer, MP_FRAGTIMER_INTERVAL,
2026                                 ng_ppp_frag_timeout, node);
2027                 priv->timerActive = 1;
2028                 node->refs++;
2029         }
2030 }
2031
2032 /*
2033  * Stop fragment queue timer
2034  */
2035 static void
2036 ng_ppp_stop_frag_timer(node_p node)
2037 {
2038         const priv_p priv = node->private;
2039
2040         if (priv->timerActive) {
2041                 callout_stop(&priv->fragTimer);
2042                 priv->timerActive = 0;
2043                 KASSERT(node->refs > 1,
2044                     ("%s: refs=%d", __func__, node->refs));
2045                 ng_unref(node);
2046         }
2047 }
2048