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

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    1 /*-
    2  * Copyright (c) 1996-2000 Whistle Communications, Inc.
    3  * All rights reserved.
    4  *
    5  * Subject to the following obligations and disclaimer of warranty, use and
    6  * redistribution of this software, in source or object code forms, with or
    7  * without modifications are expressly permitted by Whistle Communications;
    8  * provided, however, that:
    9  * 1. Any and all reproductions of the source or object code must include the
   10  *    copyright notice above and the following disclaimer of warranties; and
   11  * 2. No rights are granted, in any manner or form, to use Whistle
   12  *    Communications, Inc. trademarks, including the mark "WHISTLE
   13  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
   14  *    such appears in the above copyright notice or in the software.
   15  *
   16  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
   17  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
   18  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
   19  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
   20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
   21  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
   22  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
   23  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
   24  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
   25  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
   26  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
   27  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
   28  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
   29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   31  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
   32  * OF SUCH DAMAGE.
   33  *
   34  * Copyright (c) 2007 Alexander Motin <mav@alkar.net>
   35  * All rights reserved.
   36  *
   37  * Redistribution and use in source and binary forms, with or without
   38  * modification, are permitted provided that the following conditions
   39  * are met:
   40  * 1. Redistributions of source code must retain the above copyright
   41  *    notice unmodified, this list of conditions, and the following
   42  *    disclaimer.
   43  * 2. Redistributions in binary form must reproduce the above copyright
   44  *    notice, this list of conditions and the following disclaimer in the
   45  *    documentation and/or other materials provided with the distribution.
   46  *
   47  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   48  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   50  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   51  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   52  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   53  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   54  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   55  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   57  * SUCH DAMAGE.
   58  *
   59  * Authors: Archie Cobbs <archie@freebsd.org>, Alexander Motin <mav@alkar.net>
   60  *
   61  * $FreeBSD: stable/9/sys/netgraph/ng_ppp.c 249132 2013-04-05 08:22:11Z mav $
   62  * $Whistle: ng_ppp.c,v 1.24 1999/11/01 09:24:52 julian Exp $
   63  */
   64 
   65 /*
   66  * PPP node type data-flow.
   67  *
   68  *       hook      xmit        layer         recv      hook
   69  *              ------------------------------------
   70  *       inet ->                                    -> inet
   71  *       ipv6 ->                                    -> ipv6
   72  *        ipx ->               proto                -> ipx
   73  *      atalk ->                                    -> atalk
   74  *     bypass ->                                    -> bypass
   75  *              -hcomp_xmit()----------proto_recv()-
   76  *     vjc_ip <-                                    <- vjc_ip
   77  *   vjc_comp ->         header compression         -> vjc_comp
   78  * vjc_uncomp ->                                    -> vjc_uncomp
   79  *   vjc_vjip ->
   80  *              -comp_xmit()-----------hcomp_recv()-
   81  *   compress <-            compression             <- decompress
   82  *   compress ->                                    -> decompress
   83  *              -crypt_xmit()-----------comp_recv()-
   84  *    encrypt <-             encryption             <- decrypt
   85  *    encrypt ->                                    -> decrypt
   86  *              -ml_xmit()-------------crypt_recv()-
   87  *                           multilink
   88  *              -link_xmit()--------------ml_recv()-
   89  *      linkX <-               link                 <- linkX
   90  *
   91  */
   92 
   93 #include <sys/param.h>
   94 #include <sys/systm.h>
   95 #include <sys/kernel.h>
   96 #include <sys/limits.h>
   97 #include <sys/time.h>
   98 #include <sys/mbuf.h>
   99 #include <sys/malloc.h>
  100 #include <sys/endian.h>
  101 #include <sys/errno.h>
  102 #include <sys/ctype.h>
  103 
  104 #include <netgraph/ng_message.h>
  105 #include <netgraph/netgraph.h>
  106 #include <netgraph/ng_parse.h>
  107 #include <netgraph/ng_ppp.h>
  108 #include <netgraph/ng_vjc.h>
  109 
  110 #ifdef NG_SEPARATE_MALLOC
  111 static MALLOC_DEFINE(M_NETGRAPH_PPP, "netgraph_ppp", "netgraph ppp node");
  112 #else
  113 #define M_NETGRAPH_PPP M_NETGRAPH
  114 #endif
  115 
  116 #define PROT_VALID(p)           (((p) & 0x0101) == 0x0001)
  117 #define PROT_COMPRESSABLE(p)    (((p) & 0xff00) == 0x0000)
  118 
  119 /* Some PPP protocol numbers we're interested in */
  120 #define PROT_ATALK              0x0029
  121 #define PROT_COMPD              0x00fd
  122 #define PROT_CRYPTD             0x0053
  123 #define PROT_IP                 0x0021
  124 #define PROT_IPV6               0x0057
  125 #define PROT_IPX                0x002b
  126 #define PROT_LCP                0xc021
  127 #define PROT_MP                 0x003d
  128 #define PROT_VJCOMP             0x002d
  129 #define PROT_VJUNCOMP           0x002f
  130 
  131 /* Multilink PPP definitions */
  132 #define MP_INITIAL_SEQ          0               /* per RFC 1990 */
  133 #define MP_MIN_LINK_MRU         32
  134 
  135 #define MP_SHORT_SEQ_MASK       0x00000fff      /* short seq # mask */
  136 #define MP_SHORT_SEQ_HIBIT      0x00000800      /* short seq # high bit */
  137 #define MP_SHORT_FIRST_FLAG     0x00008000      /* first fragment in frame */
  138 #define MP_SHORT_LAST_FLAG      0x00004000      /* last fragment in frame */
  139 
  140 #define MP_LONG_SEQ_MASK        0x00ffffff      /* long seq # mask */
  141 #define MP_LONG_SEQ_HIBIT       0x00800000      /* long seq # high bit */
  142 #define MP_LONG_FIRST_FLAG      0x80000000      /* first fragment in frame */
  143 #define MP_LONG_LAST_FLAG       0x40000000      /* last fragment in frame */
  144 
  145 #define MP_NOSEQ                0x7fffffff      /* impossible sequence number */
  146 
  147 /* Sign extension of MP sequence numbers */
  148 #define MP_SHORT_EXTEND(s)      (((s) & MP_SHORT_SEQ_HIBIT) ?           \
  149                                     ((s) | ~MP_SHORT_SEQ_MASK)          \
  150                                     : ((s) & MP_SHORT_SEQ_MASK))
  151 #define MP_LONG_EXTEND(s)       (((s) & MP_LONG_SEQ_HIBIT) ?            \
  152                                     ((s) | ~MP_LONG_SEQ_MASK)           \
  153                                     : ((s) & MP_LONG_SEQ_MASK))
  154 
  155 /* Comparision of MP sequence numbers. Note: all sequence numbers
  156    except priv->xseq are stored with the sign bit extended. */
  157 #define MP_SHORT_SEQ_DIFF(x,y)  MP_SHORT_EXTEND((x) - (y))
  158 #define MP_LONG_SEQ_DIFF(x,y)   MP_LONG_EXTEND((x) - (y))
  159 
  160 #define MP_RECV_SEQ_DIFF(priv,x,y)                                      \
  161                                 ((priv)->conf.recvShortSeq ?            \
  162                                     MP_SHORT_SEQ_DIFF((x), (y)) :       \
  163                                     MP_LONG_SEQ_DIFF((x), (y)))
  164 
  165 /* Increment receive sequence number */
  166 #define MP_NEXT_RECV_SEQ(priv,seq)                                      \
  167                                 ((priv)->conf.recvShortSeq ?            \
  168                                     MP_SHORT_EXTEND((seq) + 1) :        \
  169                                     MP_LONG_EXTEND((seq) + 1))
  170 
  171 /* Don't fragment transmitted packets to parts smaller than this */
  172 #define MP_MIN_FRAG_LEN         32
  173 
  174 /* Maximum fragment reasssembly queue length */
  175 #define MP_MAX_QUEUE_LEN        128
  176 
  177 /* Fragment queue scanner period */
  178 #define MP_FRAGTIMER_INTERVAL   (hz/2)
  179 
  180 /* Average link overhead. XXX: Should be given by user-level */
  181 #define MP_AVERAGE_LINK_OVERHEAD        16
  182 
  183 /* Keep this equal to ng_ppp_hook_names lower! */
  184 #define HOOK_INDEX_MAX          13
  185 
  186 /* We store incoming fragments this way */
  187 struct ng_ppp_frag {
  188         int                             seq;            /* fragment seq# */
  189         uint8_t                         first;          /* First in packet? */
  190         uint8_t                         last;           /* Last in packet? */
  191         struct timeval                  timestamp;      /* time of reception */
  192         struct mbuf                     *data;          /* Fragment data */
  193         TAILQ_ENTRY(ng_ppp_frag)        f_qent;         /* Fragment queue */
  194 };
  195 
  196 /* Per-link private information */
  197 struct ng_ppp_link {
  198         struct ng_ppp_link_conf conf;           /* link configuration */
  199         struct ng_ppp_link_stat64       stats;  /* link stats */
  200         hook_p                  hook;           /* connection to link data */
  201         int32_t                 seq;            /* highest rec'd seq# - MSEQ */
  202         uint32_t                latency;        /* calculated link latency */
  203         struct timeval          lastWrite;      /* time of last write for MP */
  204         int                     bytesInQueue;   /* bytes in the output queue for MP */
  205 };
  206 
  207 /* Total per-node private information */
  208 struct ng_ppp_private {
  209         struct ng_ppp_bund_conf conf;                   /* bundle config */
  210         struct ng_ppp_link_stat64       bundleStats;    /* bundle stats */
  211         struct ng_ppp_link      links[NG_PPP_MAX_LINKS];/* per-link info */
  212         int32_t                 xseq;                   /* next out MP seq # */
  213         int32_t                 mseq;                   /* min links[i].seq */
  214         uint16_t                activeLinks[NG_PPP_MAX_LINKS];  /* indicies */
  215         uint16_t                numActiveLinks;         /* how many links up */
  216         uint16_t                lastLink;               /* for round robin */
  217         uint8_t                 vjCompHooked;           /* VJ comp hooked up? */
  218         uint8_t                 allLinksEqual;          /* all xmit the same? */
  219         hook_p                  hooks[HOOK_INDEX_MAX];  /* non-link hooks */
  220         struct ng_ppp_frag      fragsmem[MP_MAX_QUEUE_LEN]; /* fragments storage */
  221         TAILQ_HEAD(ng_ppp_fraglist, ng_ppp_frag)        /* fragment queue */
  222                                 frags;
  223         TAILQ_HEAD(ng_ppp_fragfreelist, ng_ppp_frag)    /* free fragment queue */
  224                                 fragsfree;
  225         struct callout          fragTimer;              /* fraq queue check */
  226         struct mtx              rmtx;                   /* recv mutex */
  227         struct mtx              xmtx;                   /* xmit mutex */
  228 };
  229 typedef struct ng_ppp_private *priv_p;
  230 
  231 /* Netgraph node methods */
  232 static ng_constructor_t ng_ppp_constructor;
  233 static ng_rcvmsg_t      ng_ppp_rcvmsg;
  234 static ng_shutdown_t    ng_ppp_shutdown;
  235 static ng_newhook_t     ng_ppp_newhook;
  236 static ng_rcvdata_t     ng_ppp_rcvdata;
  237 static ng_disconnect_t  ng_ppp_disconnect;
  238 
  239 static ng_rcvdata_t     ng_ppp_rcvdata_inet;
  240 static ng_rcvdata_t     ng_ppp_rcvdata_ipv6;
  241 static ng_rcvdata_t     ng_ppp_rcvdata_ipx;
  242 static ng_rcvdata_t     ng_ppp_rcvdata_atalk;
  243 static ng_rcvdata_t     ng_ppp_rcvdata_bypass;
  244 
  245 static ng_rcvdata_t     ng_ppp_rcvdata_vjc_ip;
  246 static ng_rcvdata_t     ng_ppp_rcvdata_vjc_comp;
  247 static ng_rcvdata_t     ng_ppp_rcvdata_vjc_uncomp;
  248 static ng_rcvdata_t     ng_ppp_rcvdata_vjc_vjip;
  249 
  250 static ng_rcvdata_t     ng_ppp_rcvdata_compress;
  251 static ng_rcvdata_t     ng_ppp_rcvdata_decompress;
  252 
  253 static ng_rcvdata_t     ng_ppp_rcvdata_encrypt;
  254 static ng_rcvdata_t     ng_ppp_rcvdata_decrypt;
  255 
  256 /* We use integer indicies to refer to the non-link hooks. */
  257 static const struct {
  258         char *const name;
  259         ng_rcvdata_t *fn;
  260 } ng_ppp_hook_names[] = {
  261 #define HOOK_INDEX_ATALK        0
  262         { NG_PPP_HOOK_ATALK,    ng_ppp_rcvdata_atalk },
  263 #define HOOK_INDEX_BYPASS       1
  264         { NG_PPP_HOOK_BYPASS,   ng_ppp_rcvdata_bypass },
  265 #define HOOK_INDEX_COMPRESS     2
  266         { NG_PPP_HOOK_COMPRESS, ng_ppp_rcvdata_compress },
  267 #define HOOK_INDEX_ENCRYPT      3
  268         { NG_PPP_HOOK_ENCRYPT,  ng_ppp_rcvdata_encrypt },
  269 #define HOOK_INDEX_DECOMPRESS   4
  270         { NG_PPP_HOOK_DECOMPRESS, ng_ppp_rcvdata_decompress },
  271 #define HOOK_INDEX_DECRYPT      5
  272         { NG_PPP_HOOK_DECRYPT,  ng_ppp_rcvdata_decrypt },
  273 #define HOOK_INDEX_INET         6
  274         { NG_PPP_HOOK_INET,     ng_ppp_rcvdata_inet },
  275 #define HOOK_INDEX_IPX          7
  276         { NG_PPP_HOOK_IPX,      ng_ppp_rcvdata_ipx },
  277 #define HOOK_INDEX_VJC_COMP     8
  278         { NG_PPP_HOOK_VJC_COMP, ng_ppp_rcvdata_vjc_comp },
  279 #define HOOK_INDEX_VJC_IP       9
  280         { NG_PPP_HOOK_VJC_IP,   ng_ppp_rcvdata_vjc_ip },
  281 #define HOOK_INDEX_VJC_UNCOMP   10
  282         { NG_PPP_HOOK_VJC_UNCOMP, ng_ppp_rcvdata_vjc_uncomp },
  283 #define HOOK_INDEX_VJC_VJIP     11
  284         { NG_PPP_HOOK_VJC_VJIP, ng_ppp_rcvdata_vjc_vjip },
  285 #define HOOK_INDEX_IPV6         12
  286         { NG_PPP_HOOK_IPV6,     ng_ppp_rcvdata_ipv6 },
  287         { NULL, NULL }
  288 };
  289 
  290 /* Helper functions */
  291 static int      ng_ppp_proto_recv(node_p node, item_p item, uint16_t proto,
  292                     uint16_t linkNum);
  293 static int      ng_ppp_hcomp_xmit(node_p node, item_p item, uint16_t proto);
  294 static int      ng_ppp_hcomp_recv(node_p node, item_p item, uint16_t proto,
  295                     uint16_t linkNum);
  296 static int      ng_ppp_comp_xmit(node_p node, item_p item, uint16_t proto);
  297 static int      ng_ppp_comp_recv(node_p node, item_p item, uint16_t proto,
  298                     uint16_t linkNum);
  299 static int      ng_ppp_crypt_xmit(node_p node, item_p item, uint16_t proto);
  300 static int      ng_ppp_crypt_recv(node_p node, item_p item, uint16_t proto,
  301                     uint16_t linkNum);
  302 static int      ng_ppp_mp_xmit(node_p node, item_p item, uint16_t proto);
  303 static int      ng_ppp_mp_recv(node_p node, item_p item, uint16_t proto,
  304                     uint16_t linkNum);
  305 static int      ng_ppp_link_xmit(node_p node, item_p item, uint16_t proto,
  306                     uint16_t linkNum, int plen);
  307 
  308 static int      ng_ppp_bypass(node_p node, item_p item, uint16_t proto,
  309                     uint16_t linkNum);
  310 
  311 static void     ng_ppp_bump_mseq(node_p node, int32_t new_mseq);
  312 static int      ng_ppp_frag_drop(node_p node);
  313 static int      ng_ppp_check_packet(node_p node);
  314 static void     ng_ppp_get_packet(node_p node, struct mbuf **mp);
  315 static int      ng_ppp_frag_process(node_p node, item_p oitem);
  316 static int      ng_ppp_frag_trim(node_p node);
  317 static void     ng_ppp_frag_timeout(node_p node, hook_p hook, void *arg1,
  318                     int arg2);
  319 static void     ng_ppp_frag_checkstale(node_p node);
  320 static void     ng_ppp_frag_reset(node_p node);
  321 static void     ng_ppp_mp_strategy(node_p node, int len, int *distrib);
  322 static int      ng_ppp_intcmp(void *latency, const void *v1, const void *v2);
  323 static struct mbuf *ng_ppp_addproto(struct mbuf *m, uint16_t proto, int compOK);
  324 static struct mbuf *ng_ppp_cutproto(struct mbuf *m, uint16_t *proto);
  325 static struct mbuf *ng_ppp_prepend(struct mbuf *m, const void *buf, int len);
  326 static int      ng_ppp_config_valid(node_p node,
  327                     const struct ng_ppp_node_conf *newConf);
  328 static void     ng_ppp_update(node_p node, int newConf);
  329 static void     ng_ppp_start_frag_timer(node_p node);
  330 static void     ng_ppp_stop_frag_timer(node_p node);
  331 
  332 /* Parse type for struct ng_ppp_mp_state_type */
  333 static const struct ng_parse_fixedarray_info ng_ppp_rseq_array_info = {
  334         &ng_parse_hint32_type,
  335         NG_PPP_MAX_LINKS
  336 };
  337 static const struct ng_parse_type ng_ppp_rseq_array_type = {
  338         &ng_parse_fixedarray_type,
  339         &ng_ppp_rseq_array_info,
  340 };
  341 static const struct ng_parse_struct_field ng_ppp_mp_state_type_fields[]
  342         = NG_PPP_MP_STATE_TYPE_INFO(&ng_ppp_rseq_array_type);
  343 static const struct ng_parse_type ng_ppp_mp_state_type = {
  344         &ng_parse_struct_type,
  345         &ng_ppp_mp_state_type_fields
  346 };
  347 
  348 /* Parse type for struct ng_ppp_link_conf */
  349 static const struct ng_parse_struct_field ng_ppp_link_type_fields[]
  350         = NG_PPP_LINK_TYPE_INFO;
  351 static const struct ng_parse_type ng_ppp_link_type = {
  352         &ng_parse_struct_type,
  353         &ng_ppp_link_type_fields
  354 };
  355 
  356 /* Parse type for struct ng_ppp_bund_conf */
  357 static const struct ng_parse_struct_field ng_ppp_bund_type_fields[]
  358         = NG_PPP_BUND_TYPE_INFO;
  359 static const struct ng_parse_type ng_ppp_bund_type = {
  360         &ng_parse_struct_type,
  361         &ng_ppp_bund_type_fields
  362 };
  363 
  364 /* Parse type for struct ng_ppp_node_conf */
  365 static const struct ng_parse_fixedarray_info ng_ppp_array_info = {
  366         &ng_ppp_link_type,
  367         NG_PPP_MAX_LINKS
  368 };
  369 static const struct ng_parse_type ng_ppp_link_array_type = {
  370         &ng_parse_fixedarray_type,
  371         &ng_ppp_array_info,
  372 };
  373 static const struct ng_parse_struct_field ng_ppp_conf_type_fields[]
  374         = NG_PPP_CONFIG_TYPE_INFO(&ng_ppp_bund_type, &ng_ppp_link_array_type);
  375 static const struct ng_parse_type ng_ppp_conf_type = {
  376         &ng_parse_struct_type,
  377         &ng_ppp_conf_type_fields
  378 };
  379 
  380 /* Parse type for struct ng_ppp_link_stat */
  381 static const struct ng_parse_struct_field ng_ppp_stats_type_fields[]
  382         = NG_PPP_STATS_TYPE_INFO;
  383 static const struct ng_parse_type ng_ppp_stats_type = {
  384         &ng_parse_struct_type,
  385         &ng_ppp_stats_type_fields
  386 };
  387 
  388 /* Parse type for struct ng_ppp_link_stat64 */
  389 static const struct ng_parse_struct_field ng_ppp_stats64_type_fields[]
  390         = NG_PPP_STATS64_TYPE_INFO;
  391 static const struct ng_parse_type ng_ppp_stats64_type = {
  392         &ng_parse_struct_type,
  393         &ng_ppp_stats64_type_fields
  394 };
  395 
  396 /* List of commands and how to convert arguments to/from ASCII */
  397 static const struct ng_cmdlist ng_ppp_cmds[] = {
  398         {
  399           NGM_PPP_COOKIE,
  400           NGM_PPP_SET_CONFIG,
  401           "setconfig",
  402           &ng_ppp_conf_type,
  403           NULL
  404         },
  405         {
  406           NGM_PPP_COOKIE,
  407           NGM_PPP_GET_CONFIG,
  408           "getconfig",
  409           NULL,
  410           &ng_ppp_conf_type
  411         },
  412         {
  413           NGM_PPP_COOKIE,
  414           NGM_PPP_GET_MP_STATE,
  415           "getmpstate",
  416           NULL,
  417           &ng_ppp_mp_state_type
  418         },
  419         {
  420           NGM_PPP_COOKIE,
  421           NGM_PPP_GET_LINK_STATS,
  422           "getstats",
  423           &ng_parse_int16_type,
  424           &ng_ppp_stats_type
  425         },
  426         {
  427           NGM_PPP_COOKIE,
  428           NGM_PPP_CLR_LINK_STATS,
  429           "clrstats",
  430           &ng_parse_int16_type,
  431           NULL
  432         },
  433         {
  434           NGM_PPP_COOKIE,
  435           NGM_PPP_GETCLR_LINK_STATS,
  436           "getclrstats",
  437           &ng_parse_int16_type,
  438           &ng_ppp_stats_type
  439         },
  440         {
  441           NGM_PPP_COOKIE,
  442           NGM_PPP_GET_LINK_STATS64,
  443           "getstats64",
  444           &ng_parse_int16_type,
  445           &ng_ppp_stats64_type
  446         },
  447         {
  448           NGM_PPP_COOKIE,
  449           NGM_PPP_GETCLR_LINK_STATS64,
  450           "getclrstats64",
  451           &ng_parse_int16_type,
  452           &ng_ppp_stats64_type
  453         },
  454         { 0 }
  455 };
  456 
  457 /* Node type descriptor */
  458 static struct ng_type ng_ppp_typestruct = {
  459         .version =      NG_ABI_VERSION,
  460         .name =         NG_PPP_NODE_TYPE,
  461         .constructor =  ng_ppp_constructor,
  462         .rcvmsg =       ng_ppp_rcvmsg,
  463         .shutdown =     ng_ppp_shutdown,
  464         .newhook =      ng_ppp_newhook,
  465         .rcvdata =      ng_ppp_rcvdata,
  466         .disconnect =   ng_ppp_disconnect,
  467         .cmdlist =      ng_ppp_cmds,
  468 };
  469 NETGRAPH_INIT(ppp, &ng_ppp_typestruct);
  470 
  471 /* Address and control field header */
  472 static const uint8_t ng_ppp_acf[2] = { 0xff, 0x03 };
  473 
  474 /* Maximum time we'll let a complete incoming packet sit in the queue */
  475 static const struct timeval ng_ppp_max_staleness = { 2, 0 };    /* 2 seconds */
  476 
  477 #define ERROUT(x)       do { error = (x); goto done; } while (0)
  478 
  479 /************************************************************************
  480                         NETGRAPH NODE STUFF
  481  ************************************************************************/
  482 
  483 /*
  484  * Node type constructor
  485  */
  486 static int
  487 ng_ppp_constructor(node_p node)
  488 {
  489         priv_p priv;
  490         int i;
  491 
  492         /* Allocate private structure */
  493         priv = malloc(sizeof(*priv), M_NETGRAPH_PPP, M_WAITOK | M_ZERO);
  494 
  495         NG_NODE_SET_PRIVATE(node, priv);
  496 
  497         /* Initialize state */
  498         TAILQ_INIT(&priv->frags);
  499         TAILQ_INIT(&priv->fragsfree);
  500         for (i = 0; i < MP_MAX_QUEUE_LEN; i++)
  501                 TAILQ_INSERT_TAIL(&priv->fragsfree, &priv->fragsmem[i], f_qent);
  502         for (i = 0; i < NG_PPP_MAX_LINKS; i++)
  503                 priv->links[i].seq = MP_NOSEQ;
  504         ng_callout_init(&priv->fragTimer);
  505 
  506         mtx_init(&priv->rmtx, "ng_ppp_recv", NULL, MTX_DEF);
  507         mtx_init(&priv->xmtx, "ng_ppp_xmit", NULL, MTX_DEF);
  508 
  509         /* Done */
  510         return (0);
  511 }
  512 
  513 /*
  514  * Give our OK for a hook to be added
  515  */
  516 static int
  517 ng_ppp_newhook(node_p node, hook_p hook, const char *name)
  518 {
  519         const priv_p priv = NG_NODE_PRIVATE(node);
  520         hook_p *hookPtr = NULL;
  521         int linkNum = -1;
  522         int hookIndex = -1;
  523 
  524         /* Figure out which hook it is */
  525         if (strncmp(name, NG_PPP_HOOK_LINK_PREFIX,      /* a link hook? */
  526             strlen(NG_PPP_HOOK_LINK_PREFIX)) == 0) {
  527                 const char *cp;
  528                 char *eptr;
  529 
  530                 cp = name + strlen(NG_PPP_HOOK_LINK_PREFIX);
  531                 if (!isdigit(*cp) || (cp[0] == '' && cp[1] != '\0'))
  532                         return (EINVAL);
  533                 linkNum = (int)strtoul(cp, &eptr, 10);
  534                 if (*eptr != '\0' || linkNum < 0 || linkNum >= NG_PPP_MAX_LINKS)
  535                         return (EINVAL);
  536                 hookPtr = &priv->links[linkNum].hook;
  537                 hookIndex = ~linkNum;
  538 
  539                 /* See if hook is already connected. */
  540                 if (*hookPtr != NULL)
  541                         return (EISCONN);
  542 
  543                 /* Disallow more than one link unless multilink is enabled. */
  544                 if (priv->links[linkNum].conf.enableLink &&
  545                     !priv->conf.enableMultilink && priv->numActiveLinks >= 1)
  546                         return (ENODEV);
  547 
  548         } else {                                /* must be a non-link hook */
  549                 int i;
  550 
  551                 for (i = 0; ng_ppp_hook_names[i].name != NULL; i++) {
  552                         if (strcmp(name, ng_ppp_hook_names[i].name) == 0) {
  553                                 hookPtr = &priv->hooks[i];
  554                                 hookIndex = i;
  555                                 break;
  556                         }
  557                 }
  558                 if (ng_ppp_hook_names[i].name == NULL)
  559                         return (EINVAL);        /* no such hook */
  560 
  561                 /* See if hook is already connected */
  562                 if (*hookPtr != NULL)
  563                         return (EISCONN);
  564 
  565                 /* Every non-linkX hook have it's own function. */
  566                 NG_HOOK_SET_RCVDATA(hook, ng_ppp_hook_names[i].fn);
  567         }
  568 
  569         /* OK */
  570         *hookPtr = hook;
  571         NG_HOOK_SET_PRIVATE(hook, (void *)(intptr_t)hookIndex);
  572         ng_ppp_update(node, 0);
  573         return (0);
  574 }
  575 
  576 /*
  577  * Receive a control message
  578  */
  579 static int
  580 ng_ppp_rcvmsg(node_p node, item_p item, hook_p lasthook)
  581 {
  582         const priv_p priv = NG_NODE_PRIVATE(node);
  583         struct ng_mesg *resp = NULL;
  584         int error = 0;
  585         struct ng_mesg *msg;
  586 
  587         NGI_GET_MSG(item, msg);
  588         switch (msg->header.typecookie) {
  589         case NGM_PPP_COOKIE:
  590                 switch (msg->header.cmd) {
  591                 case NGM_PPP_SET_CONFIG:
  592                     {
  593                         struct ng_ppp_node_conf *const conf =
  594                             (struct ng_ppp_node_conf *)msg->data;
  595                         int i;
  596 
  597                         /* Check for invalid or illegal config */
  598                         if (msg->header.arglen != sizeof(*conf))
  599                                 ERROUT(EINVAL);
  600                         if (!ng_ppp_config_valid(node, conf))
  601                                 ERROUT(EINVAL);
  602 
  603                         /* Copy config */
  604                         priv->conf = conf->bund;
  605                         for (i = 0; i < NG_PPP_MAX_LINKS; i++)
  606                                 priv->links[i].conf = conf->links[i];
  607                         ng_ppp_update(node, 1);
  608                         break;
  609                     }
  610                 case NGM_PPP_GET_CONFIG:
  611                     {
  612                         struct ng_ppp_node_conf *conf;
  613                         int i;
  614 
  615                         NG_MKRESPONSE(resp, msg, sizeof(*conf), M_NOWAIT);
  616                         if (resp == NULL)
  617                                 ERROUT(ENOMEM);
  618                         conf = (struct ng_ppp_node_conf *)resp->data;
  619                         conf->bund = priv->conf;
  620                         for (i = 0; i < NG_PPP_MAX_LINKS; i++)
  621                                 conf->links[i] = priv->links[i].conf;
  622                         break;
  623                     }
  624                 case NGM_PPP_GET_MP_STATE:
  625                     {
  626                         struct ng_ppp_mp_state *info;
  627                         int i;
  628 
  629                         NG_MKRESPONSE(resp, msg, sizeof(*info), M_NOWAIT);
  630                         if (resp == NULL)
  631                                 ERROUT(ENOMEM);
  632                         info = (struct ng_ppp_mp_state *)resp->data;
  633                         bzero(info, sizeof(*info));
  634                         for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
  635                                 if (priv->links[i].seq != MP_NOSEQ)
  636                                         info->rseq[i] = priv->links[i].seq;
  637                         }
  638                         info->mseq = priv->mseq;
  639                         info->xseq = priv->xseq;
  640                         break;
  641                     }
  642                 case NGM_PPP_GET_LINK_STATS:
  643                 case NGM_PPP_CLR_LINK_STATS:
  644                 case NGM_PPP_GETCLR_LINK_STATS:
  645                 case NGM_PPP_GET_LINK_STATS64:
  646                 case NGM_PPP_GETCLR_LINK_STATS64:
  647                     {
  648                         struct ng_ppp_link_stat64 *stats;
  649                         uint16_t linkNum;
  650 
  651                         /* Process request. */
  652                         if (msg->header.arglen != sizeof(uint16_t))
  653                                 ERROUT(EINVAL);
  654                         linkNum = *((uint16_t *) msg->data);
  655                         if (linkNum >= NG_PPP_MAX_LINKS
  656                             && linkNum != NG_PPP_BUNDLE_LINKNUM)
  657                                 ERROUT(EINVAL);
  658                         stats = (linkNum == NG_PPP_BUNDLE_LINKNUM) ?
  659                             &priv->bundleStats : &priv->links[linkNum].stats;
  660 
  661                         /* Make 64bit reply. */
  662                         if (msg->header.cmd == NGM_PPP_GET_LINK_STATS64 || 
  663                             msg->header.cmd == NGM_PPP_GETCLR_LINK_STATS64) {
  664                                 NG_MKRESPONSE(resp, msg,
  665                                     sizeof(struct ng_ppp_link_stat64), M_NOWAIT);
  666                                 if (resp == NULL)
  667                                         ERROUT(ENOMEM);
  668                                 bcopy(stats, resp->data, sizeof(*stats));
  669                         } else
  670                         /* Make 32bit reply. */
  671                         if (msg->header.cmd == NGM_PPP_GET_LINK_STATS || 
  672                             msg->header.cmd == NGM_PPP_GETCLR_LINK_STATS) {
  673                                 struct ng_ppp_link_stat *rs;
  674                                 NG_MKRESPONSE(resp, msg,
  675                                     sizeof(struct ng_ppp_link_stat), M_NOWAIT);
  676                                 if (resp == NULL)
  677                                         ERROUT(ENOMEM);
  678                                 rs = (struct ng_ppp_link_stat *)resp->data;
  679                                 /* Truncate 64->32 bits. */
  680                                 rs->xmitFrames = stats->xmitFrames;
  681                                 rs->xmitOctets = stats->xmitOctets;
  682                                 rs->recvFrames = stats->recvFrames;
  683                                 rs->recvOctets = stats->recvOctets;
  684                                 rs->badProtos = stats->badProtos;
  685                                 rs->runts = stats->runts;
  686                                 rs->dupFragments = stats->dupFragments;
  687                                 rs->dropFragments = stats->dropFragments;
  688                         }
  689                         /* Clear stats. */
  690                         if (msg->header.cmd != NGM_PPP_GET_LINK_STATS &&
  691                             msg->header.cmd != NGM_PPP_GET_LINK_STATS64)
  692                                 bzero(stats, sizeof(*stats));
  693                         break;
  694                     }
  695                 default:
  696                         error = EINVAL;
  697                         break;
  698                 }
  699                 break;
  700         case NGM_VJC_COOKIE:
  701             {
  702                 /*
  703                  * Forward it to the vjc node. leave the
  704                  * old return address alone.
  705                  * If we have no hook, let NG_RESPOND_MSG
  706                  * clean up any remaining resources.
  707                  * Because we have no resp, the item will be freed
  708                  * along with anything it references. Don't
  709                  * let msg be freed twice.
  710                  */
  711                 NGI_MSG(item) = msg;    /* put it back in the item */
  712                 msg = NULL;
  713                 if ((lasthook = priv->hooks[HOOK_INDEX_VJC_IP])) {
  714                         NG_FWD_ITEM_HOOK(error, item, lasthook);
  715                 }
  716                 return (error);
  717             }
  718         default:
  719                 error = EINVAL;
  720                 break;
  721         }
  722 done:
  723         NG_RESPOND_MSG(error, node, item, resp);
  724         NG_FREE_MSG(msg);
  725         return (error);
  726 }
  727 
  728 /*
  729  * Destroy node
  730  */
  731 static int
  732 ng_ppp_shutdown(node_p node)
  733 {
  734         const priv_p priv = NG_NODE_PRIVATE(node);
  735 
  736         /* Stop fragment queue timer */
  737         ng_ppp_stop_frag_timer(node);
  738 
  739         /* Take down netgraph node */
  740         ng_ppp_frag_reset(node);
  741         mtx_destroy(&priv->rmtx);
  742         mtx_destroy(&priv->xmtx);
  743         bzero(priv, sizeof(*priv));
  744         free(priv, M_NETGRAPH_PPP);
  745         NG_NODE_SET_PRIVATE(node, NULL);
  746         NG_NODE_UNREF(node);            /* let the node escape */
  747         return (0);
  748 }
  749 
  750 /*
  751  * Hook disconnection
  752  */
  753 static int
  754 ng_ppp_disconnect(hook_p hook)
  755 {
  756         const node_p node = NG_HOOK_NODE(hook);
  757         const priv_p priv = NG_NODE_PRIVATE(node);
  758         const int index = (intptr_t)NG_HOOK_PRIVATE(hook);
  759 
  760         /* Zero out hook pointer */
  761         if (index < 0)
  762                 priv->links[~index].hook = NULL;
  763         else
  764                 priv->hooks[index] = NULL;
  765 
  766         /* Update derived info (or go away if no hooks left). */
  767         if (NG_NODE_NUMHOOKS(node) > 0)
  768                 ng_ppp_update(node, 0);
  769         else if (NG_NODE_IS_VALID(node))
  770                 ng_rmnode_self(node);
  771 
  772         return (0);
  773 }
  774 
  775 /*
  776  * Proto layer
  777  */
  778 
  779 /*
  780  * Receive data on a hook inet.
  781  */
  782 static int
  783 ng_ppp_rcvdata_inet(hook_p hook, item_p item)
  784 {
  785         const node_p node = NG_HOOK_NODE(hook);
  786         const priv_p priv = NG_NODE_PRIVATE(node);
  787 
  788         if (!priv->conf.enableIP) {
  789                 NG_FREE_ITEM(item);
  790                 return (ENXIO);
  791         }
  792         return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_IP));
  793 }
  794 
  795 /*
  796  * Receive data on a hook ipv6.
  797  */
  798 static int
  799 ng_ppp_rcvdata_ipv6(hook_p hook, item_p item)
  800 {
  801         const node_p node = NG_HOOK_NODE(hook);
  802         const priv_p priv = NG_NODE_PRIVATE(node);
  803 
  804         if (!priv->conf.enableIPv6) {
  805                 NG_FREE_ITEM(item);
  806                 return (ENXIO);
  807         }
  808         return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_IPV6));
  809 }
  810 
  811 /*
  812  * Receive data on a hook atalk.
  813  */
  814 static int
  815 ng_ppp_rcvdata_atalk(hook_p hook, item_p item)
  816 {
  817         const node_p node = NG_HOOK_NODE(hook);
  818         const priv_p priv = NG_NODE_PRIVATE(node);
  819 
  820         if (!priv->conf.enableAtalk) {
  821                 NG_FREE_ITEM(item);
  822                 return (ENXIO);
  823         }
  824         return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_ATALK));
  825 }
  826 
  827 /*
  828  * Receive data on a hook ipx
  829  */
  830 static int
  831 ng_ppp_rcvdata_ipx(hook_p hook, item_p item)
  832 {
  833         const node_p node = NG_HOOK_NODE(hook);
  834         const priv_p priv = NG_NODE_PRIVATE(node);
  835 
  836         if (!priv->conf.enableIPX) {
  837                 NG_FREE_ITEM(item);
  838                 return (ENXIO);
  839         }
  840         return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_IPX));
  841 }
  842 
  843 /*
  844  * Receive data on a hook bypass
  845  */
  846 static int
  847 ng_ppp_rcvdata_bypass(hook_p hook, item_p item)
  848 {
  849         uint16_t linkNum;
  850         uint16_t proto;
  851         struct mbuf *m;
  852 
  853         NGI_GET_M(item, m);
  854         if (m->m_pkthdr.len < 4) {
  855                 NG_FREE_ITEM(item);
  856                 return (EINVAL);
  857         }
  858         if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
  859                 NG_FREE_ITEM(item);
  860                 return (ENOBUFS);
  861         }
  862         linkNum = be16dec(mtod(m, uint8_t *));
  863         proto = be16dec(mtod(m, uint8_t *) + 2);
  864         m_adj(m, 4);
  865         NGI_M(item) = m;
  866 
  867         if (linkNum == NG_PPP_BUNDLE_LINKNUM)
  868                 return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, proto));
  869         else
  870                 return (ng_ppp_link_xmit(NG_HOOK_NODE(hook), item, proto,
  871                     linkNum, 0));
  872 }
  873 
  874 static int
  875 ng_ppp_bypass(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
  876 {
  877         const priv_p priv = NG_NODE_PRIVATE(node);
  878         uint16_t hdr[2];
  879         struct mbuf *m;
  880         int error;
  881 
  882         if (priv->hooks[HOOK_INDEX_BYPASS] == NULL) {
  883             NG_FREE_ITEM(item);
  884             return (ENXIO);
  885         }
  886 
  887         /* Add 4-byte bypass header. */
  888         hdr[0] = htons(linkNum);
  889         hdr[1] = htons(proto);
  890 
  891         NGI_GET_M(item, m);
  892         if ((m = ng_ppp_prepend(m, &hdr, 4)) == NULL) {
  893                 NG_FREE_ITEM(item);
  894                 return (ENOBUFS);
  895         }
  896         NGI_M(item) = m;
  897 
  898         /* Send packet out hook. */
  899         NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_BYPASS]);
  900         return (error);
  901 }
  902 
  903 static int
  904 ng_ppp_proto_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
  905 {
  906         const priv_p priv = NG_NODE_PRIVATE(node);
  907         hook_p outHook = NULL;
  908         int error;
  909 #ifdef ALIGNED_POINTER
  910         struct mbuf *m, *n;
  911 
  912         NGI_GET_M(item, m);
  913         if (!ALIGNED_POINTER(mtod(m, caddr_t), uint32_t)) {
  914                 n = m_defrag(m, M_NOWAIT);
  915                 if (n == NULL) {
  916                         m_freem(m);
  917                         NG_FREE_ITEM(item);
  918                         return (ENOBUFS);
  919                 }
  920                 m = n;
  921         }
  922         NGI_M(item) = m;
  923 #endif /* ALIGNED_POINTER */
  924         switch (proto) {
  925             case PROT_IP:
  926                 if (priv->conf.enableIP)
  927                     outHook = priv->hooks[HOOK_INDEX_INET];
  928                 break;
  929             case PROT_IPV6:
  930                 if (priv->conf.enableIPv6)
  931                     outHook = priv->hooks[HOOK_INDEX_IPV6];
  932                 break;
  933             case PROT_ATALK:
  934                 if (priv->conf.enableAtalk)
  935                     outHook = priv->hooks[HOOK_INDEX_ATALK];
  936                 break;
  937             case PROT_IPX:
  938                 if (priv->conf.enableIPX)
  939                     outHook = priv->hooks[HOOK_INDEX_IPX];
  940                 break;
  941         }
  942 
  943         if (outHook == NULL)
  944                 return (ng_ppp_bypass(node, item, proto, linkNum));
  945 
  946         /* Send packet out hook. */
  947         NG_FWD_ITEM_HOOK(error, item, outHook);
  948         return (error);
  949 }
  950 
  951 /*
  952  * Header compression layer
  953  */
  954 
  955 static int
  956 ng_ppp_hcomp_xmit(node_p node, item_p item, uint16_t proto)
  957 {
  958         const priv_p priv = NG_NODE_PRIVATE(node);
  959 
  960         if (proto == PROT_IP &&
  961             priv->conf.enableVJCompression &&
  962             priv->vjCompHooked) {
  963                 int error;
  964 
  965                 /* Send packet out hook. */
  966                 NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_VJC_IP]);
  967                 return (error);
  968         }
  969 
  970         return (ng_ppp_comp_xmit(node, item, proto));
  971 }
  972 
  973 /*
  974  * Receive data on a hook vjc_comp.
  975  */
  976 static int
  977 ng_ppp_rcvdata_vjc_comp(hook_p hook, item_p item)
  978 {
  979         const node_p node = NG_HOOK_NODE(hook);
  980         const priv_p priv = NG_NODE_PRIVATE(node);
  981 
  982         if (!priv->conf.enableVJCompression) {
  983                 NG_FREE_ITEM(item);
  984                 return (ENXIO);
  985         }
  986         return (ng_ppp_comp_xmit(node, item, PROT_VJCOMP));
  987 }
  988 
  989 /*
  990  * Receive data on a hook vjc_uncomp.
  991  */
  992 static int
  993 ng_ppp_rcvdata_vjc_uncomp(hook_p hook, item_p item)
  994 {
  995         const node_p node = NG_HOOK_NODE(hook);
  996         const priv_p priv = NG_NODE_PRIVATE(node);
  997 
  998         if (!priv->conf.enableVJCompression) {
  999                 NG_FREE_ITEM(item);
 1000                 return (ENXIO);
 1001         }
 1002         return (ng_ppp_comp_xmit(node, item, PROT_VJUNCOMP));
 1003 }
 1004 
 1005 /*
 1006  * Receive data on a hook vjc_vjip.
 1007  */
 1008 static int
 1009 ng_ppp_rcvdata_vjc_vjip(hook_p hook, item_p item)
 1010 {
 1011         const node_p node = NG_HOOK_NODE(hook);
 1012         const priv_p priv = NG_NODE_PRIVATE(node);
 1013 
 1014         if (!priv->conf.enableVJCompression) {
 1015                 NG_FREE_ITEM(item);
 1016                 return (ENXIO);
 1017         }
 1018         return (ng_ppp_comp_xmit(node, item, PROT_IP));
 1019 }
 1020 
 1021 static int
 1022 ng_ppp_hcomp_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
 1023 {
 1024         const priv_p priv = NG_NODE_PRIVATE(node);
 1025 
 1026         if (priv->conf.enableVJDecompression && priv->vjCompHooked) {
 1027                 hook_p outHook = NULL;
 1028 
 1029                 switch (proto) {
 1030                     case PROT_VJCOMP:
 1031                         outHook = priv->hooks[HOOK_INDEX_VJC_COMP];
 1032                         break;
 1033                     case PROT_VJUNCOMP:
 1034                         outHook = priv->hooks[HOOK_INDEX_VJC_UNCOMP];
 1035                         break;
 1036                 }
 1037 
 1038                 if (outHook) {
 1039                         int error;
 1040 
 1041                         /* Send packet out hook. */
 1042                         NG_FWD_ITEM_HOOK(error, item, outHook);
 1043                         return (error);
 1044                 }
 1045         }
 1046 
 1047         return (ng_ppp_proto_recv(node, item, proto, linkNum));
 1048 }
 1049 
 1050 /*
 1051  * Receive data on a hook vjc_ip.
 1052  */
 1053 static int
 1054 ng_ppp_rcvdata_vjc_ip(hook_p hook, item_p item)
 1055 {
 1056         const node_p node = NG_HOOK_NODE(hook);
 1057         const priv_p priv = NG_NODE_PRIVATE(node);
 1058 
 1059         if (!priv->conf.enableVJDecompression) {
 1060                 NG_FREE_ITEM(item);
 1061                 return (ENXIO);
 1062         }
 1063         return (ng_ppp_proto_recv(node, item, PROT_IP, NG_PPP_BUNDLE_LINKNUM));
 1064 }
 1065 
 1066 /*
 1067  * Compression layer
 1068  */
 1069 
 1070 static int
 1071 ng_ppp_comp_xmit(node_p node, item_p item, uint16_t proto)
 1072 {
 1073         const priv_p priv = NG_NODE_PRIVATE(node);
 1074 
 1075         if (priv->conf.enableCompression &&
 1076             proto < 0x4000 &&
 1077             proto != PROT_COMPD &&
 1078             proto != PROT_CRYPTD &&
 1079             priv->hooks[HOOK_INDEX_COMPRESS] != NULL) {
 1080                 struct mbuf *m;
 1081                 int error;
 1082 
 1083                 NGI_GET_M(item, m);
 1084                 if ((m = ng_ppp_addproto(m, proto, 0)) == NULL) {
 1085                         NG_FREE_ITEM(item);
 1086                         return (ENOBUFS);
 1087                 }
 1088                 NGI_M(item) = m;
 1089 
 1090                 /* Send packet out hook. */
 1091                 NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_COMPRESS]);
 1092                 return (error);
 1093         }
 1094 
 1095         return (ng_ppp_crypt_xmit(node, item, proto));
 1096 }
 1097 
 1098 /*
 1099  * Receive data on a hook compress.
 1100  */
 1101 static int
 1102 ng_ppp_rcvdata_compress(hook_p hook, item_p item)
 1103 {
 1104         const node_p node = NG_HOOK_NODE(hook);
 1105         const priv_p priv = NG_NODE_PRIVATE(node);
 1106         uint16_t proto;
 1107 
 1108         switch (priv->conf.enableCompression) {
 1109             case NG_PPP_COMPRESS_NONE:
 1110                 NG_FREE_ITEM(item);
 1111                 return (ENXIO);
 1112             case NG_PPP_COMPRESS_FULL:
 1113                 {
 1114                         struct mbuf *m;
 1115 
 1116                         NGI_GET_M(item, m);
 1117                         if ((m = ng_ppp_cutproto(m, &proto)) == NULL) {
 1118                                 NG_FREE_ITEM(item);
 1119                                 return (EIO);
 1120                         }
 1121                         NGI_M(item) = m;
 1122                         if (!PROT_VALID(proto)) {
 1123                                 NG_FREE_ITEM(item);
 1124                                 return (EIO);
 1125                         }
 1126                 }
 1127                 break;
 1128             default:
 1129                 proto = PROT_COMPD;
 1130                 break;
 1131         }
 1132         return (ng_ppp_crypt_xmit(node, item, proto));
 1133 }
 1134 
 1135 static int
 1136 ng_ppp_comp_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
 1137 {
 1138         const priv_p priv = NG_NODE_PRIVATE(node);
 1139 
 1140         if (proto < 0x4000 &&
 1141             ((proto == PROT_COMPD && priv->conf.enableDecompression) ||
 1142             priv->conf.enableDecompression == NG_PPP_DECOMPRESS_FULL) &&
 1143             priv->hooks[HOOK_INDEX_DECOMPRESS] != NULL) {
 1144                 int error;
 1145 
 1146                 if (priv->conf.enableDecompression == NG_PPP_DECOMPRESS_FULL) {
 1147                         struct mbuf *m;
 1148                         NGI_GET_M(item, m);
 1149                         if ((m = ng_ppp_addproto(m, proto, 0)) == NULL) {
 1150                                 NG_FREE_ITEM(item);
 1151                                 return (EIO);
 1152                         }
 1153                         NGI_M(item) = m;
 1154                 }
 1155 
 1156                 /* Send packet out hook. */
 1157                 NG_FWD_ITEM_HOOK(error, item,
 1158                     priv->hooks[HOOK_INDEX_DECOMPRESS]);
 1159                 return (error);
 1160         } else if (proto == PROT_COMPD) {
 1161                 /* Disabled protos MUST be silently discarded, but
 1162                  * unsupported MUST not. Let user-level decide this. */
 1163                 return (ng_ppp_bypass(node, item, proto, linkNum));
 1164         }
 1165 
 1166         return (ng_ppp_hcomp_recv(node, item, proto, linkNum));
 1167 }
 1168 
 1169 /*
 1170  * Receive data on a hook decompress.
 1171  */
 1172 static int
 1173 ng_ppp_rcvdata_decompress(hook_p hook, item_p item)
 1174 {
 1175         const node_p node = NG_HOOK_NODE(hook);
 1176         const priv_p priv = NG_NODE_PRIVATE(node);
 1177         uint16_t proto;
 1178         struct mbuf *m;
 1179 
 1180         if (!priv->conf.enableDecompression) {
 1181                 NG_FREE_ITEM(item);
 1182                 return (ENXIO);
 1183         }
 1184         NGI_GET_M(item, m);
 1185         if ((m = ng_ppp_cutproto(m, &proto)) == NULL) {
 1186                 NG_FREE_ITEM(item);
 1187                 return (EIO);
 1188         }
 1189         NGI_M(item) = m;
 1190         if (!PROT_VALID(proto)) {
 1191                 priv->bundleStats.badProtos++;
 1192                 NG_FREE_ITEM(item);
 1193                 return (EIO);
 1194         }
 1195         return (ng_ppp_hcomp_recv(node, item, proto, NG_PPP_BUNDLE_LINKNUM));
 1196 }
 1197 
 1198 /*
 1199  * Encryption layer
 1200  */
 1201 
 1202 static int
 1203 ng_ppp_crypt_xmit(node_p node, item_p item, uint16_t proto)
 1204 {
 1205         const priv_p priv = NG_NODE_PRIVATE(node);
 1206 
 1207         if (priv->conf.enableEncryption &&
 1208             proto < 0x4000 &&
 1209             proto != PROT_CRYPTD &&
 1210             priv->hooks[HOOK_INDEX_ENCRYPT] != NULL) {
 1211                 struct mbuf *m;
 1212                 int error;
 1213 
 1214                 NGI_GET_M(item, m);
 1215                 if ((m = ng_ppp_addproto(m, proto, 0)) == NULL) {
 1216                         NG_FREE_ITEM(item);
 1217                         return (ENOBUFS);
 1218                 }
 1219                 NGI_M(item) = m;
 1220 
 1221                 /* Send packet out hook. */
 1222                 NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_ENCRYPT]);
 1223                 return (error);
 1224         }
 1225 
 1226         return (ng_ppp_mp_xmit(node, item, proto));
 1227 }
 1228 
 1229 /*
 1230  * Receive data on a hook encrypt.
 1231  */
 1232 static int
 1233 ng_ppp_rcvdata_encrypt(hook_p hook, item_p item)
 1234 {
 1235         const node_p node = NG_HOOK_NODE(hook);
 1236         const priv_p priv = NG_NODE_PRIVATE(node);
 1237 
 1238         if (!priv->conf.enableEncryption) {
 1239                 NG_FREE_ITEM(item);
 1240                 return (ENXIO);
 1241         }
 1242         return (ng_ppp_mp_xmit(node, item, PROT_CRYPTD));
 1243 }
 1244 
 1245 static int
 1246 ng_ppp_crypt_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
 1247 {
 1248         const priv_p priv = NG_NODE_PRIVATE(node);
 1249 
 1250         if (proto == PROT_CRYPTD) {
 1251                 if (priv->conf.enableDecryption &&
 1252                     priv->hooks[HOOK_INDEX_DECRYPT] != NULL) {
 1253                         int error;
 1254 
 1255                         /* Send packet out hook. */
 1256                         NG_FWD_ITEM_HOOK(error, item,
 1257                             priv->hooks[HOOK_INDEX_DECRYPT]);
 1258                         return (error);
 1259                 } else {
 1260                         /* Disabled protos MUST be silently discarded, but
 1261                          * unsupported MUST not. Let user-level decide this. */
 1262                         return (ng_ppp_bypass(node, item, proto, linkNum));
 1263                 }
 1264         }
 1265 
 1266         return (ng_ppp_comp_recv(node, item, proto, linkNum));
 1267 }
 1268 
 1269 /*
 1270  * Receive data on a hook decrypt.
 1271  */
 1272 static int
 1273 ng_ppp_rcvdata_decrypt(hook_p hook, item_p item)
 1274 {
 1275         const node_p node = NG_HOOK_NODE(hook);
 1276         const priv_p priv = NG_NODE_PRIVATE(node);
 1277         uint16_t proto;
 1278         struct mbuf *m;
 1279 
 1280         if (!priv->conf.enableDecryption) {
 1281                 NG_FREE_ITEM(item);
 1282                 return (ENXIO);
 1283         }
 1284         NGI_GET_M(item, m);
 1285         if ((m = ng_ppp_cutproto(m, &proto)) == NULL) {
 1286                 NG_FREE_ITEM(item);
 1287                 return (EIO);
 1288         }
 1289         NGI_M(item) = m;
 1290         if (!PROT_VALID(proto)) {
 1291                 priv->bundleStats.badProtos++;
 1292                 NG_FREE_ITEM(item);
 1293                 return (EIO);
 1294         }
 1295         return (ng_ppp_comp_recv(node, item, proto, NG_PPP_BUNDLE_LINKNUM));
 1296 }
 1297 
 1298 /*
 1299  * Link layer
 1300  */
 1301 
 1302 static int
 1303 ng_ppp_link_xmit(node_p node, item_p item, uint16_t proto, uint16_t linkNum, int plen)
 1304 {
 1305         const priv_p priv = NG_NODE_PRIVATE(node);
 1306         struct ng_ppp_link *link;
 1307         int len, error;
 1308         struct mbuf *m;
 1309         uint16_t mru;
 1310 
 1311         /* Check if link correct. */
 1312         if (linkNum >= NG_PPP_MAX_LINKS) {
 1313                 ERROUT(ENETDOWN);
 1314         }
 1315 
 1316         /* Get link pointer (optimization). */
 1317         link = &priv->links[linkNum];
 1318 
 1319         /* Check link status (if real). */
 1320         if (link->hook == NULL) {
 1321                 ERROUT(ENETDOWN);
 1322         }
 1323 
 1324         /* Extract mbuf. */
 1325         NGI_GET_M(item, m);
 1326 
 1327         /* Check peer's MRU for this link. */
 1328         mru = link->conf.mru;
 1329         if (mru != 0 && m->m_pkthdr.len > mru) {
 1330                 NG_FREE_M(m);
 1331                 ERROUT(EMSGSIZE);
 1332         }
 1333 
 1334         /* Prepend protocol number, possibly compressed. */
 1335         if ((m = ng_ppp_addproto(m, proto, link->conf.enableProtoComp)) ==
 1336             NULL) {
 1337                 ERROUT(ENOBUFS);
 1338         }
 1339 
 1340         /* Prepend address and control field (unless compressed). */
 1341         if (proto == PROT_LCP || !link->conf.enableACFComp) {
 1342                 if ((m = ng_ppp_prepend(m, &ng_ppp_acf, 2)) == NULL)
 1343                         ERROUT(ENOBUFS);
 1344         }
 1345 
 1346         /* Deliver frame. */
 1347         len = m->m_pkthdr.len;
 1348         NG_FWD_NEW_DATA(error, item, link->hook, m);
 1349 
 1350         mtx_lock(&priv->xmtx);
 1351 
 1352         /* Update link stats. */
 1353         link->stats.xmitFrames++;
 1354         link->stats.xmitOctets += len;
 1355 
 1356         /* Update bundle stats. */
 1357         if (plen > 0) {
 1358             priv->bundleStats.xmitFrames++;
 1359             priv->bundleStats.xmitOctets += plen;
 1360         }
 1361 
 1362         /* Update 'bytes in queue' counter. */
 1363         if (error == 0) {
 1364                 /* bytesInQueue and lastWrite required only for mp_strategy. */
 1365                 if (priv->conf.enableMultilink && !priv->allLinksEqual &&
 1366                     !priv->conf.enableRoundRobin) {
 1367                         /* If queue was empty, then mark this time. */
 1368                         if (link->bytesInQueue == 0)
 1369                                 getmicrouptime(&link->lastWrite);
 1370                         link->bytesInQueue += len + MP_AVERAGE_LINK_OVERHEAD;
 1371                         /* Limit max queue length to 50 pkts. BW can be defined
 1372                            incorrectly and link may not signal overload. */
 1373                         if (link->bytesInQueue > 50 * 1600)
 1374                                 link->bytesInQueue = 50 * 1600;
 1375                 }
 1376         }
 1377         mtx_unlock(&priv->xmtx);
 1378         return (error);
 1379 
 1380 done:
 1381         NG_FREE_ITEM(item);
 1382         return (error);
 1383 }
 1384 
 1385 /*
 1386  * Receive data on a hook linkX.
 1387  */
 1388 static int
 1389 ng_ppp_rcvdata(hook_p hook, item_p item)
 1390 {
 1391         const node_p node = NG_HOOK_NODE(hook);
 1392         const priv_p priv = NG_NODE_PRIVATE(node);
 1393         const int index = (intptr_t)NG_HOOK_PRIVATE(hook);
 1394         const uint16_t linkNum = (uint16_t)~index;
 1395         struct ng_ppp_link * const link = &priv->links[linkNum];
 1396         uint16_t proto;
 1397         struct mbuf *m;
 1398         int error = 0;
 1399 
 1400         KASSERT(linkNum < NG_PPP_MAX_LINKS,
 1401             ("%s: bogus index 0x%x", __func__, index));
 1402 
 1403         NGI_GET_M(item, m);
 1404 
 1405         mtx_lock(&priv->rmtx);
 1406 
 1407         /* Stats */
 1408         link->stats.recvFrames++;
 1409         link->stats.recvOctets += m->m_pkthdr.len;
 1410 
 1411         /* Strip address and control fields, if present. */
 1412         if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL)
 1413                 ERROUT(ENOBUFS);
 1414         if (mtod(m, uint8_t *)[0] == 0xff &&
 1415             mtod(m, uint8_t *)[1] == 0x03)
 1416                 m_adj(m, 2);
 1417 
 1418         /* Get protocol number */
 1419         if ((m = ng_ppp_cutproto(m, &proto)) == NULL)
 1420                 ERROUT(ENOBUFS);
 1421         NGI_M(item) = m;        /* Put changed m back into item. */
 1422 
 1423         if (!PROT_VALID(proto)) {
 1424                 link->stats.badProtos++;
 1425                 ERROUT(EIO);
 1426         }
 1427 
 1428         /* LCP packets must go directly to bypass. */
 1429         if (proto >= 0xB000) {
 1430                 mtx_unlock(&priv->rmtx);
 1431                 return (ng_ppp_bypass(node, item, proto, linkNum));
 1432         }
 1433         
 1434         /* Other packets are denied on a disabled link. */
 1435         if (!link->conf.enableLink)
 1436                 ERROUT(ENXIO);
 1437 
 1438         /* Proceed to multilink layer. Mutex will be unlocked inside. */
 1439         error = ng_ppp_mp_recv(node, item, proto, linkNum);
 1440         mtx_assert(&priv->rmtx, MA_NOTOWNED);
 1441         return (error);
 1442 
 1443 done:
 1444         mtx_unlock(&priv->rmtx);
 1445         NG_FREE_ITEM(item);
 1446         return (error);
 1447 }
 1448 
 1449 /*
 1450  * Multilink layer
 1451  */
 1452 
 1453 /*
 1454  * Handle an incoming multi-link fragment
 1455  *
 1456  * The fragment reassembly algorithm is somewhat complex. This is mainly
 1457  * because we are required not to reorder the reconstructed packets, yet
 1458  * fragments are only guaranteed to arrive in order on a per-link basis.
 1459  * In other words, when we have a complete packet ready, but the previous
 1460  * packet is still incomplete, we have to decide between delivering the
 1461  * complete packet and throwing away the incomplete one, or waiting to
 1462  * see if the remainder of the incomplete one arrives, at which time we
 1463  * can deliver both packets, in order.
 1464  *
 1465  * This problem is exacerbated by "sequence number slew", which is when
 1466  * the sequence numbers coming in from different links are far apart from
 1467  * each other. In particular, certain unnamed equipment (*cough* Ascend)
 1468  * has been seen to generate sequence number slew of up to 10 on an ISDN
 1469  * 2B-channel MP link. There is nothing invalid about sequence number slew
 1470  * but it makes the reasssembly process have to work harder.
 1471  *
 1472  * However, the peer is required to transmit fragments in order on each
 1473  * link. That means if we define MSEQ as the minimum over all links of
 1474  * the highest sequence number received on that link, then we can always
 1475  * give up any hope of receiving a fragment with sequence number < MSEQ in
 1476  * the future (all of this using 'wraparound' sequence number space).
 1477  * Therefore we can always immediately throw away incomplete packets
 1478  * missing fragments with sequence numbers < MSEQ.
 1479  *
 1480  * Here is an overview of our algorithm:
 1481  *
 1482  *    o Received fragments are inserted into a queue, for which we
 1483  *      maintain these invariants between calls to this function:
 1484  *
 1485  *      - Fragments are ordered in the queue by sequence number
 1486  *      - If a complete packet is at the head of the queue, then
 1487  *        the first fragment in the packet has seq# > MSEQ + 1
 1488  *        (otherwise, we could deliver it immediately)
 1489  *      - If any fragments have seq# < MSEQ, then they are necessarily
 1490  *        part of a packet whose missing seq#'s are all > MSEQ (otherwise,
 1491  *        we can throw them away because they'll never be completed)
 1492  *      - The queue contains at most MP_MAX_QUEUE_LEN fragments
 1493  *
 1494  *    o We have a periodic timer that checks the queue for the first
 1495  *      complete packet that has been sitting in the queue "too long".
 1496  *      When one is detected, all previous (incomplete) fragments are
 1497  *      discarded, their missing fragments are declared lost and MSEQ
 1498  *      is increased.
 1499  *
 1500  *    o If we recieve a fragment with seq# < MSEQ, we throw it away
 1501  *      because we've already delcared it lost.
 1502  *
 1503  * This assumes linkNum != NG_PPP_BUNDLE_LINKNUM.
 1504  */
 1505 static int
 1506 ng_ppp_mp_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
 1507 {
 1508         const priv_p priv = NG_NODE_PRIVATE(node);
 1509         struct ng_ppp_link *const link = &priv->links[linkNum];
 1510         struct ng_ppp_frag *frag;
 1511         struct ng_ppp_frag *qent;
 1512         int i, diff, inserted;
 1513         struct mbuf *m;
 1514         int     error = 0;
 1515 
 1516         if ((!priv->conf.enableMultilink) || proto != PROT_MP) {
 1517                 /* Stats */
 1518                 priv->bundleStats.recvFrames++;
 1519                 priv->bundleStats.recvOctets += NGI_M(item)->m_pkthdr.len;
 1520 
 1521                 mtx_unlock(&priv->rmtx);
 1522                 return (ng_ppp_crypt_recv(node, item, proto, linkNum));
 1523         }
 1524 
 1525         NGI_GET_M(item, m);
 1526 
 1527         /* Get a new frag struct from the free queue */
 1528         if ((frag = TAILQ_FIRST(&priv->fragsfree)) == NULL) {
 1529                 printf("No free fragments headers in ng_ppp!\n");
 1530                 NG_FREE_M(m);
 1531                 goto process;
 1532         }
 1533 
 1534         /* Extract fragment information from MP header */
 1535         if (priv->conf.recvShortSeq) {
 1536                 uint16_t shdr;
 1537 
 1538                 if (m->m_pkthdr.len < 2) {
 1539                         link->stats.runts++;
 1540                         NG_FREE_M(m);
 1541                         ERROUT(EINVAL);
 1542                 }
 1543                 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL)
 1544                         ERROUT(ENOBUFS);
 1545 
 1546                 shdr = be16dec(mtod(m, void *));
 1547                 frag->seq = MP_SHORT_EXTEND(shdr);
 1548                 frag->first = (shdr & MP_SHORT_FIRST_FLAG) != 0;
 1549                 frag->last = (shdr & MP_SHORT_LAST_FLAG) != 0;
 1550                 diff = MP_SHORT_SEQ_DIFF(frag->seq, priv->mseq);
 1551                 m_adj(m, 2);
 1552         } else {
 1553                 uint32_t lhdr;
 1554 
 1555                 if (m->m_pkthdr.len < 4) {
 1556                         link->stats.runts++;
 1557                         NG_FREE_M(m);
 1558                         ERROUT(EINVAL);
 1559                 }
 1560                 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL)
 1561                         ERROUT(ENOBUFS);
 1562 
 1563                 lhdr = be32dec(mtod(m, void *));
 1564                 frag->seq = MP_LONG_EXTEND(lhdr);
 1565                 frag->first = (lhdr & MP_LONG_FIRST_FLAG) != 0;
 1566                 frag->last = (lhdr & MP_LONG_LAST_FLAG) != 0;
 1567                 diff = MP_LONG_SEQ_DIFF(frag->seq, priv->mseq);
 1568                 m_adj(m, 4);
 1569         }
 1570         frag->data = m;
 1571         getmicrouptime(&frag->timestamp);
 1572 
 1573         /* If sequence number is < MSEQ, we've already declared this
 1574            fragment as lost, so we have no choice now but to drop it */
 1575         if (diff < 0) {
 1576                 link->stats.dropFragments++;
 1577                 NG_FREE_M(m);
 1578                 ERROUT(0);
 1579         }
 1580 
 1581         /* Update highest received sequence number on this link and MSEQ */
 1582         priv->mseq = link->seq = frag->seq;
 1583         for (i = 0; i < priv->numActiveLinks; i++) {
 1584                 struct ng_ppp_link *const alink =
 1585                     &priv->links[priv->activeLinks[i]];
 1586 
 1587                 if (MP_RECV_SEQ_DIFF(priv, alink->seq, priv->mseq) < 0)
 1588                         priv->mseq = alink->seq;
 1589         }
 1590 
 1591         /* Remove frag struct from free queue. */
 1592         TAILQ_REMOVE(&priv->fragsfree, frag, f_qent);
 1593 
 1594         /* Add fragment to queue, which is sorted by sequence number */
 1595         inserted = 0;
 1596         TAILQ_FOREACH_REVERSE(qent, &priv->frags, ng_ppp_fraglist, f_qent) {
 1597                 diff = MP_RECV_SEQ_DIFF(priv, frag->seq, qent->seq);
 1598                 if (diff > 0) {
 1599                         TAILQ_INSERT_AFTER(&priv->frags, qent, frag, f_qent);
 1600                         inserted = 1;
 1601                         break;
 1602                 } else if (diff == 0) {      /* should never happen! */
 1603                         link->stats.dupFragments++;
 1604                         NG_FREE_M(frag->data);
 1605                         TAILQ_INSERT_HEAD(&priv->fragsfree, frag, f_qent);
 1606                         ERROUT(EINVAL);
 1607                 }
 1608         }
 1609         if (!inserted)
 1610                 TAILQ_INSERT_HEAD(&priv->frags, frag, f_qent);
 1611 
 1612 process:
 1613         /* Process the queue */
 1614         /* NOTE: rmtx will be unlocked for sending time! */
 1615         error = ng_ppp_frag_process(node, item);
 1616         mtx_unlock(&priv->rmtx);
 1617         return (error);
 1618 
 1619 done:
 1620         mtx_unlock(&priv->rmtx);
 1621         NG_FREE_ITEM(item);
 1622         return (error);
 1623 }
 1624 
 1625 /************************************************************************
 1626                         HELPER STUFF
 1627  ************************************************************************/
 1628 
 1629 /*
 1630  * If new mseq > current then set it and update all active links
 1631  */
 1632 static void
 1633 ng_ppp_bump_mseq(node_p node, int32_t new_mseq)
 1634 {
 1635         const priv_p priv = NG_NODE_PRIVATE(node);
 1636         int i;
 1637         
 1638         if (MP_RECV_SEQ_DIFF(priv, priv->mseq, new_mseq) < 0) {
 1639                 priv->mseq = new_mseq;
 1640                 for (i = 0; i < priv->numActiveLinks; i++) {
 1641                         struct ng_ppp_link *const alink =
 1642                             &priv->links[priv->activeLinks[i]];
 1643 
 1644                         if (MP_RECV_SEQ_DIFF(priv,
 1645                             alink->seq, new_mseq) < 0)
 1646                                 alink->seq = new_mseq;
 1647                 }
 1648         }
 1649 }
 1650 
 1651 /*
 1652  * Examine our list of fragments, and determine if there is a
 1653  * complete and deliverable packet at the head of the list.
 1654  * Return 1 if so, zero otherwise.
 1655  */
 1656 static int
 1657 ng_ppp_check_packet(node_p node)
 1658 {
 1659         const priv_p priv = NG_NODE_PRIVATE(node);
 1660         struct ng_ppp_frag *qent, *qnext;
 1661 
 1662         /* Check for empty queue */
 1663         if (TAILQ_EMPTY(&priv->frags))
 1664                 return (0);
 1665 
 1666         /* Check first fragment is the start of a deliverable packet */
 1667         qent = TAILQ_FIRST(&priv->frags);
 1668         if (!qent->first || MP_RECV_SEQ_DIFF(priv, qent->seq, priv->mseq) > 1)
 1669                 return (0);
 1670 
 1671         /* Check that all the fragments are there */
 1672         while (!qent->last) {
 1673                 qnext = TAILQ_NEXT(qent, f_qent);
 1674                 if (qnext == NULL)      /* end of queue */
 1675                         return (0);
 1676                 if (qnext->seq != MP_NEXT_RECV_SEQ(priv, qent->seq))
 1677                         return (0);
 1678                 qent = qnext;
 1679         }
 1680 
 1681         /* Got one */
 1682         return (1);
 1683 }
 1684 
 1685 /*
 1686  * Pull a completed packet off the head of the incoming fragment queue.
 1687  * This assumes there is a completed packet there to pull off.
 1688  */
 1689 static void
 1690 ng_ppp_get_packet(node_p node, struct mbuf **mp)
 1691 {
 1692         const priv_p priv = NG_NODE_PRIVATE(node);
 1693         struct ng_ppp_frag *qent, *qnext;
 1694         struct mbuf *m = NULL, *tail;
 1695 
 1696         qent = TAILQ_FIRST(&priv->frags);
 1697         KASSERT(!TAILQ_EMPTY(&priv->frags) && qent->first,
 1698             ("%s: no packet", __func__));
 1699         for (tail = NULL; qent != NULL; qent = qnext) {
 1700                 qnext = TAILQ_NEXT(qent, f_qent);
 1701                 KASSERT(!TAILQ_EMPTY(&priv->frags),
 1702                     ("%s: empty q", __func__));
 1703                 TAILQ_REMOVE(&priv->frags, qent, f_qent);
 1704                 if (tail == NULL)
 1705                         tail = m = qent->data;
 1706                 else {
 1707                         m->m_pkthdr.len += qent->data->m_pkthdr.len;
 1708                         tail->m_next = qent->data;
 1709                 }
 1710                 while (tail->m_next != NULL)
 1711                         tail = tail->m_next;
 1712                 if (qent->last) {
 1713                         qnext = NULL;
 1714                         /* Bump MSEQ if necessary */
 1715                         ng_ppp_bump_mseq(node, qent->seq);
 1716                 }
 1717                 TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
 1718         }
 1719         *mp = m;
 1720 }
 1721 
 1722 /*
 1723  * Trim fragments from the queue whose packets can never be completed.
 1724  * This assumes a complete packet is NOT at the beginning of the queue.
 1725  * Returns 1 if fragments were removed, zero otherwise.
 1726  */
 1727 static int
 1728 ng_ppp_frag_trim(node_p node)
 1729 {
 1730         const priv_p priv = NG_NODE_PRIVATE(node);
 1731         struct ng_ppp_frag *qent, *qnext = NULL;
 1732         int removed = 0;
 1733 
 1734         /* Scan for "dead" fragments and remove them */
 1735         while (1) {
 1736                 int dead = 0;
 1737 
 1738                 /* If queue is empty, we're done */
 1739                 if (TAILQ_EMPTY(&priv->frags))
 1740                         break;
 1741 
 1742                 /* Determine whether first fragment can ever be completed */
 1743                 TAILQ_FOREACH(qent, &priv->frags, f_qent) {
 1744                         if (MP_RECV_SEQ_DIFF(priv, qent->seq, priv->mseq) >= 0)
 1745                                 break;
 1746                         qnext = TAILQ_NEXT(qent, f_qent);
 1747                         KASSERT(qnext != NULL,
 1748                             ("%s: last frag < MSEQ?", __func__));
 1749                         if (qnext->seq != MP_NEXT_RECV_SEQ(priv, qent->seq)
 1750                             || qent->last || qnext->first) {
 1751                                 dead = 1;
 1752                                 break;
 1753                         }
 1754                 }
 1755                 if (!dead)
 1756                         break;
 1757 
 1758                 /* Remove fragment and all others in the same packet */
 1759                 while ((qent = TAILQ_FIRST(&priv->frags)) != qnext) {
 1760                         KASSERT(!TAILQ_EMPTY(&priv->frags),
 1761                             ("%s: empty q", __func__));
 1762                         priv->bundleStats.dropFragments++;
 1763                         TAILQ_REMOVE(&priv->frags, qent, f_qent);
 1764                         NG_FREE_M(qent->data);
 1765                         TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
 1766                         removed = 1;
 1767                 }
 1768         }
 1769         return (removed);
 1770 }
 1771 
 1772 /*
 1773  * Drop fragments on queue overflow.
 1774  * Returns 1 if fragments were removed, zero otherwise.
 1775  */
 1776 static int
 1777 ng_ppp_frag_drop(node_p node)
 1778 {
 1779         const priv_p priv = NG_NODE_PRIVATE(node);
 1780 
 1781         /* Check queue length */
 1782         if (TAILQ_EMPTY(&priv->fragsfree)) {
 1783                 struct ng_ppp_frag *qent;
 1784 
 1785                 /* Get oldest fragment */
 1786                 KASSERT(!TAILQ_EMPTY(&priv->frags),
 1787                     ("%s: empty q", __func__));
 1788                 qent = TAILQ_FIRST(&priv->frags);
 1789 
 1790                 /* Bump MSEQ if necessary */
 1791                 ng_ppp_bump_mseq(node, qent->seq);
 1792 
 1793                 /* Drop it */
 1794                 priv->bundleStats.dropFragments++;
 1795                 TAILQ_REMOVE(&priv->frags, qent, f_qent);
 1796                 NG_FREE_M(qent->data);
 1797                 TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
 1798 
 1799                 return (1);
 1800         }
 1801         return (0);
 1802 }
 1803 
 1804 /*
 1805  * Run the queue, restoring the queue invariants
 1806  */
 1807 static int
 1808 ng_ppp_frag_process(node_p node, item_p oitem)
 1809 {
 1810         const priv_p priv = NG_NODE_PRIVATE(node);
 1811         struct mbuf *m;
 1812         item_p item;
 1813         uint16_t proto;
 1814 
 1815         do {
 1816                 /* Deliver any deliverable packets */
 1817                 while (ng_ppp_check_packet(node)) {
 1818                         ng_ppp_get_packet(node, &m);
 1819                         if ((m = ng_ppp_cutproto(m, &proto)) == NULL)
 1820                                 continue;
 1821                         if (!PROT_VALID(proto)) {
 1822                                 priv->bundleStats.badProtos++;
 1823                                 NG_FREE_M(m);
 1824                                 continue;
 1825                         }
 1826                         if (oitem) { /* If original item present - reuse it. */
 1827                                 item = oitem;
 1828                                 oitem = NULL;
 1829                                 NGI_M(item) = m;
 1830                         } else {
 1831                                 item = ng_package_data(m, NG_NOFLAGS);
 1832                         }
 1833                         if (item != NULL) {
 1834                                 /* Stats */
 1835                                 priv->bundleStats.recvFrames++;
 1836                                 priv->bundleStats.recvOctets += 
 1837                                     NGI_M(item)->m_pkthdr.len;
 1838 
 1839                                 /* Drop mutex for the sending time.
 1840                                  * Priv may change, but we are ready!
 1841                                  */
 1842                                 mtx_unlock(&priv->rmtx);
 1843                                 ng_ppp_crypt_recv(node, item, proto,
 1844                                         NG_PPP_BUNDLE_LINKNUM);
 1845                                 mtx_lock(&priv->rmtx);
 1846                         }
 1847                 }
 1848           /* Delete dead fragments and try again */
 1849         } while (ng_ppp_frag_trim(node) || ng_ppp_frag_drop(node));
 1850         
 1851         /* If we haven't reused original item - free it. */
 1852         if (oitem) NG_FREE_ITEM(oitem);
 1853 
 1854         /* Done */
 1855         return (0);
 1856 }
 1857 
 1858 /*
 1859  * Check for 'stale' completed packets that need to be delivered
 1860  *
 1861  * If a link goes down or has a temporary failure, MSEQ can get
 1862  * "stuck", because no new incoming fragments appear on that link.
 1863  * This can cause completed packets to never get delivered if
 1864  * their sequence numbers are all > MSEQ + 1.
 1865  *
 1866  * This routine checks how long all of the completed packets have
 1867  * been sitting in the queue, and if too long, removes fragments
 1868  * from the queue and increments MSEQ to allow them to be delivered.
 1869  */
 1870 static void
 1871 ng_ppp_frag_checkstale(node_p node)
 1872 {
 1873         const priv_p priv = NG_NODE_PRIVATE(node);
 1874         struct ng_ppp_frag *qent, *beg, *end;
 1875         struct timeval now, age;
 1876         struct mbuf *m;
 1877         int seq;
 1878         item_p item;
 1879         int endseq;
 1880         uint16_t proto;
 1881 
 1882         now.tv_sec = 0;                 /* uninitialized state */
 1883         while (1) {
 1884 
 1885                 /* If queue is empty, we're done */
 1886                 if (TAILQ_EMPTY(&priv->frags))
 1887                         break;
 1888 
 1889                 /* Find the first complete packet in the queue */
 1890                 beg = end = NULL;
 1891                 seq = TAILQ_FIRST(&priv->frags)->seq;
 1892                 TAILQ_FOREACH(qent, &priv->frags, f_qent) {
 1893                         if (qent->first)
 1894                                 beg = qent;
 1895                         else if (qent->seq != seq)
 1896                                 beg = NULL;
 1897                         if (beg != NULL && qent->last) {
 1898                                 end = qent;
 1899                                 break;
 1900                         }
 1901                         seq = MP_NEXT_RECV_SEQ(priv, seq);
 1902                 }
 1903 
 1904                 /* If none found, exit */
 1905                 if (end == NULL)
 1906                         break;
 1907 
 1908                 /* Get current time (we assume we've been up for >= 1 second) */
 1909                 if (now.tv_sec == 0)
 1910                         getmicrouptime(&now);
 1911 
 1912                 /* Check if packet has been queued too long */
 1913                 age = now;
 1914                 timevalsub(&age, &beg->timestamp);
 1915                 if (timevalcmp(&age, &ng_ppp_max_staleness, < ))
 1916                         break;
 1917 
 1918                 /* Throw away junk fragments in front of the completed packet */
 1919                 while ((qent = TAILQ_FIRST(&priv->frags)) != beg) {
 1920                         KASSERT(!TAILQ_EMPTY(&priv->frags),
 1921                             ("%s: empty q", __func__));
 1922                         priv->bundleStats.dropFragments++;
 1923                         TAILQ_REMOVE(&priv->frags, qent, f_qent);
 1924                         NG_FREE_M(qent->data);
 1925                         TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
 1926                 }
 1927 
 1928                 /* Extract completed packet */
 1929                 endseq = end->seq;
 1930                 ng_ppp_get_packet(node, &m);
 1931 
 1932                 if ((m = ng_ppp_cutproto(m, &proto)) == NULL)
 1933                         continue;
 1934                 if (!PROT_VALID(proto)) {
 1935                         priv->bundleStats.badProtos++;
 1936                         NG_FREE_M(m);
 1937                         continue;
 1938                 }
 1939 
 1940                 /* Deliver packet */
 1941                 if ((item = ng_package_data(m, NG_NOFLAGS)) != NULL) {
 1942                         /* Stats */
 1943                         priv->bundleStats.recvFrames++;
 1944                         priv->bundleStats.recvOctets += NGI_M(item)->m_pkthdr.len;
 1945 
 1946                         ng_ppp_crypt_recv(node, item, proto,
 1947                                 NG_PPP_BUNDLE_LINKNUM);
 1948                 }
 1949         }
 1950 }
 1951 
 1952 /*
 1953  * Periodically call ng_ppp_frag_checkstale()
 1954  */
 1955 static void
 1956 ng_ppp_frag_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 1957 {
 1958         /* XXX: is this needed? */
 1959         if (NG_NODE_NOT_VALID(node))
 1960                 return;
 1961 
 1962         /* Scan the fragment queue */
 1963         ng_ppp_frag_checkstale(node);
 1964 
 1965         /* Start timer again */
 1966         ng_ppp_start_frag_timer(node);
 1967 }
 1968 
 1969 /*
 1970  * Deliver a frame out on the bundle, i.e., figure out how to fragment
 1971  * the frame across the individual PPP links and do so.
 1972  */
 1973 static int
 1974 ng_ppp_mp_xmit(node_p node, item_p item, uint16_t proto)
 1975 {
 1976         const priv_p priv = NG_NODE_PRIVATE(node);
 1977         const int hdr_len = priv->conf.xmitShortSeq ? 2 : 4;
 1978         int distrib[NG_PPP_MAX_LINKS];
 1979         int firstFragment;
 1980         int activeLinkNum;
 1981         struct mbuf *m;
 1982         int     plen;
 1983         int     frags;
 1984         int32_t seq;
 1985 
 1986         /* At least one link must be active */
 1987         if (priv->numActiveLinks == 0) {
 1988                 NG_FREE_ITEM(item);
 1989                 return (ENETDOWN);
 1990         }
 1991         
 1992         /* Save length for later stats. */
 1993         plen = NGI_M(item)->m_pkthdr.len;
 1994 
 1995         if (!priv->conf.enableMultilink) {
 1996                 return (ng_ppp_link_xmit(node, item, proto,
 1997                     priv->activeLinks[0], plen));
 1998         }
 1999 
 2000         /* Check peer's MRRU for this bundle. */
 2001         if (plen > priv->conf.mrru) {
 2002                 NG_FREE_ITEM(item);
 2003                 return (EMSGSIZE);
 2004         }
 2005 
 2006         /* Extract mbuf. */
 2007         NGI_GET_M(item, m);
 2008 
 2009         /* Prepend protocol number, possibly compressed. */
 2010         if ((m = ng_ppp_addproto(m, proto, 1)) == NULL) {
 2011                 NG_FREE_ITEM(item);
 2012                 return (ENOBUFS);
 2013         }
 2014 
 2015         /* Clear distribution plan */
 2016         bzero(&distrib, priv->numActiveLinks * sizeof(distrib[0]));
 2017 
 2018         mtx_lock(&priv->xmtx);
 2019 
 2020         /* Round-robin strategy */
 2021         if (priv->conf.enableRoundRobin) {
 2022                 activeLinkNum = priv->lastLink++ % priv->numActiveLinks;
 2023                 distrib[activeLinkNum] = m->m_pkthdr.len;
 2024                 goto deliver;
 2025         }
 2026 
 2027         /* Strategy when all links are equivalent (optimize the common case) */
 2028         if (priv->allLinksEqual) {
 2029                 int     numFrags, fraction, remain;
 2030                 int     i;
 2031                 
 2032                 /* Calculate optimal fragment count */
 2033                 numFrags = priv->numActiveLinks;
 2034                 if (numFrags > m->m_pkthdr.len / MP_MIN_FRAG_LEN)
 2035                     numFrags = m->m_pkthdr.len / MP_MIN_FRAG_LEN;
 2036                 if (numFrags == 0)
 2037                     numFrags = 1;
 2038 
 2039                 fraction = m->m_pkthdr.len / numFrags;
 2040                 remain = m->m_pkthdr.len - (fraction * numFrags);
 2041                 
 2042                 /* Assign distribution */
 2043                 for (i = 0; i < numFrags; i++) {
 2044                         distrib[priv->lastLink++ % priv->numActiveLinks]
 2045                             = fraction + (((remain--) > 0)?1:0);
 2046                 }
 2047                 goto deliver;
 2048         }
 2049 
 2050         /* Strategy when all links are not equivalent */
 2051         ng_ppp_mp_strategy(node, m->m_pkthdr.len, distrib);
 2052 
 2053 deliver:
 2054         /* Estimate fragments count */
 2055         frags = 0;
 2056         for (activeLinkNum = priv->numActiveLinks - 1;
 2057             activeLinkNum >= 0; activeLinkNum--) {
 2058                 const uint16_t linkNum = priv->activeLinks[activeLinkNum];
 2059                 struct ng_ppp_link *const link = &priv->links[linkNum];
 2060                 
 2061                 frags += (distrib[activeLinkNum] + link->conf.mru - hdr_len - 1) /
 2062                     (link->conf.mru - hdr_len);
 2063         }
 2064         
 2065         /* Get out initial sequence number */
 2066         seq = priv->xseq;
 2067 
 2068         /* Update next sequence number */
 2069         if (priv->conf.xmitShortSeq) {
 2070             priv->xseq = (seq + frags) & MP_SHORT_SEQ_MASK;
 2071         } else {
 2072             priv->xseq = (seq + frags) & MP_LONG_SEQ_MASK;
 2073         }
 2074 
 2075         mtx_unlock(&priv->xmtx);
 2076 
 2077         /* Send alloted portions of frame out on the link(s) */
 2078         for (firstFragment = 1, activeLinkNum = priv->numActiveLinks - 1;
 2079             activeLinkNum >= 0; activeLinkNum--) {
 2080                 const uint16_t linkNum = priv->activeLinks[activeLinkNum];
 2081                 struct ng_ppp_link *const link = &priv->links[linkNum];
 2082 
 2083                 /* Deliver fragment(s) out the next link */
 2084                 for ( ; distrib[activeLinkNum] > 0; firstFragment = 0) {
 2085                         int len, lastFragment, error;
 2086                         struct mbuf *m2;
 2087 
 2088                         /* Calculate fragment length; don't exceed link MTU */
 2089                         len = distrib[activeLinkNum];
 2090                         if (len > link->conf.mru - hdr_len)
 2091                                 len = link->conf.mru - hdr_len;
 2092                         distrib[activeLinkNum] -= len;
 2093                         lastFragment = (len == m->m_pkthdr.len);
 2094 
 2095                         /* Split off next fragment as "m2" */
 2096                         m2 = m;
 2097                         if (!lastFragment) {
 2098                                 struct mbuf *n = m_split(m, len, M_DONTWAIT);
 2099 
 2100                                 if (n == NULL) {
 2101                                         NG_FREE_M(m);
 2102                                         if (firstFragment)
 2103                                                 NG_FREE_ITEM(item);
 2104                                         return (ENOMEM);
 2105                                 }
 2106                                 m_tag_copy_chain(n, m, M_DONTWAIT);
 2107                                 m = n;
 2108                         }
 2109 
 2110                         /* Prepend MP header */
 2111                         if (priv->conf.xmitShortSeq) {
 2112                                 uint16_t shdr;
 2113 
 2114                                 shdr = seq;
 2115                                 seq = (seq + 1) & MP_SHORT_SEQ_MASK;
 2116                                 if (firstFragment)
 2117                                         shdr |= MP_SHORT_FIRST_FLAG;
 2118                                 if (lastFragment)
 2119                                         shdr |= MP_SHORT_LAST_FLAG;
 2120                                 shdr = htons(shdr);
 2121                                 m2 = ng_ppp_prepend(m2, &shdr, 2);
 2122                         } else {
 2123                                 uint32_t lhdr;
 2124 
 2125                                 lhdr = seq;
 2126                                 seq = (seq + 1) & MP_LONG_SEQ_MASK;
 2127                                 if (firstFragment)
 2128                                         lhdr |= MP_LONG_FIRST_FLAG;
 2129                                 if (lastFragment)
 2130                                         lhdr |= MP_LONG_LAST_FLAG;
 2131                                 lhdr = htonl(lhdr);
 2132                                 m2 = ng_ppp_prepend(m2, &lhdr, 4);
 2133                         }
 2134                         if (m2 == NULL) {
 2135                                 if (!lastFragment)
 2136                                         m_freem(m);
 2137                                 if (firstFragment)
 2138                                         NG_FREE_ITEM(item);
 2139                                 return (ENOBUFS);
 2140                         }
 2141 
 2142                         /* Send fragment */
 2143                         if (firstFragment) {
 2144                                 NGI_M(item) = m2; /* Reuse original item. */
 2145                         } else {
 2146                                 item = ng_package_data(m2, NG_NOFLAGS);
 2147                         }
 2148                         if (item != NULL) {
 2149                                 error = ng_ppp_link_xmit(node, item, PROT_MP,
 2150                                             linkNum, (firstFragment?plen:0));
 2151                                 if (error != 0) {
 2152                                         if (!lastFragment)
 2153                                                 NG_FREE_M(m);
 2154                                         return (error);
 2155                                 }
 2156                         }
 2157                 }
 2158         }
 2159 
 2160         /* Done */
 2161         return (0);
 2162 }
 2163 
 2164 /*
 2165  * Computing the optimal fragmentation
 2166  * -----------------------------------
 2167  *
 2168  * This routine tries to compute the optimal fragmentation pattern based
 2169  * on each link's latency, bandwidth, and calculated additional latency.
 2170  * The latter quantity is the additional latency caused by previously
 2171  * written data that has not been transmitted yet.
 2172  *
 2173  * This algorithm is only useful when not all of the links have the
 2174  * same latency and bandwidth values.
 2175  *
 2176  * The essential idea is to make the last bit of each fragment of the
 2177  * frame arrive at the opposite end at the exact same time. This greedy
 2178  * algorithm is optimal, in that no other scheduling could result in any
 2179  * packet arriving any sooner unless packets are delivered out of order.
 2180  *
 2181  * Suppose link i has bandwidth b_i (in tens of bytes per milisecond) and
 2182  * latency l_i (in miliseconds). Consider the function function f_i(t)
 2183  * which is equal to the number of bytes that will have arrived at
 2184  * the peer after t miliseconds if we start writing continuously at
 2185  * time t = 0. Then f_i(t) = b_i * (t - l_i) = ((b_i * t) - (l_i * b_i).
 2186  * That is, f_i(t) is a line with slope b_i and y-intersect -(l_i * b_i).
 2187  * Note that the y-intersect is always <= zero because latency can't be
 2188  * negative.  Note also that really the function is f_i(t) except when
 2189  * f_i(t) is negative, in which case the function is zero.  To take
 2190  * care of this, let Q_i(t) = { if (f_i(t) > 0) return 1; else return 0; }.
 2191  * So the actual number of bytes that will have arrived at the peer after
 2192  * t miliseconds is f_i(t) * Q_i(t).
 2193  *
 2194  * At any given time, each link has some additional latency a_i >= 0
 2195  * due to previously written fragment(s) which are still in the queue.
 2196  * This value is easily computed from the time since last transmission,
 2197  * the previous latency value, the number of bytes written, and the
 2198  * link's bandwidth.
 2199  *
 2200  * Assume that l_i includes any a_i already, and that the links are
 2201  * sorted by latency, so that l_i <= l_{i+1}.
 2202  *
 2203  * Let N be the total number of bytes in the current frame we are sending.
 2204  *
 2205  * Suppose we were to start writing bytes at time t = 0 on all links
 2206  * simultaneously, which is the most we can possibly do.  Then let
 2207  * F(t) be equal to the total number of bytes received by the peer
 2208  * after t miliseconds. Then F(t) = Sum_i (f_i(t) * Q_i(t)).
 2209  *
 2210  * Our goal is simply this: fragment the frame across the links such
 2211  * that the peer is able to reconstruct the completed frame as soon as
 2212  * possible, i.e., at the least possible value of t. Call this value t_0.
 2213  *
 2214  * Then it follows that F(t_0) = N. Our strategy is first to find the value
 2215  * of t_0, and then deduce how many bytes to write to each link.
 2216  *
 2217  * Rewriting F(t_0):
 2218  *
 2219  *   t_0 = ( N + Sum_i ( l_i * b_i * Q_i(t_0) ) ) / Sum_i ( b_i * Q_i(t_0) )
 2220  *
 2221  * Now, we note that Q_i(t) is constant for l_i <= t <= l_{i+1}. t_0 will
 2222  * lie in one of these ranges.  To find it, we just need to find the i such
 2223  * that F(l_i) <= N <= F(l_{i+1}).  Then we compute all the constant values
 2224  * for Q_i() in this range, plug in the remaining values, solving for t_0.
 2225  *
 2226  * Once t_0 is known, then the number of bytes to send on link i is
 2227  * just f_i(t_0) * Q_i(t_0).
 2228  *
 2229  * In other words, we start allocating bytes to the links one at a time.
 2230  * We keep adding links until the frame is completely sent.  Some links
 2231  * may not get any bytes because their latency is too high.
 2232  *
 2233  * Is all this work really worth the trouble?  Depends on the situation.
 2234  * The bigger the ratio of computer speed to link speed, and the more
 2235  * important total bundle latency is (e.g., for interactive response time),
 2236  * the more it's worth it.  There is however the cost of calling this
 2237  * function for every frame.  The running time is O(n^2) where n is the
 2238  * number of links that receive a non-zero number of bytes.
 2239  *
 2240  * Since latency is measured in miliseconds, the "resolution" of this
 2241  * algorithm is one milisecond.
 2242  *
 2243  * To avoid this algorithm altogether, configure all links to have the
 2244  * same latency and bandwidth.
 2245  */
 2246 static void
 2247 ng_ppp_mp_strategy(node_p node, int len, int *distrib)
 2248 {
 2249         const priv_p priv = NG_NODE_PRIVATE(node);
 2250         int latency[NG_PPP_MAX_LINKS];
 2251         int sortByLatency[NG_PPP_MAX_LINKS];
 2252         int activeLinkNum;
 2253         int t0, total, topSum, botSum;
 2254         struct timeval now;
 2255         int i, numFragments;
 2256 
 2257         /* If only one link, this gets real easy */
 2258         if (priv->numActiveLinks == 1) {
 2259                 distrib[0] = len;
 2260                 return;
 2261         }
 2262 
 2263         /* Get current time */
 2264         getmicrouptime(&now);
 2265 
 2266         /* Compute latencies for each link at this point in time */
 2267         for (activeLinkNum = 0;
 2268             activeLinkNum < priv->numActiveLinks; activeLinkNum++) {
 2269                 struct ng_ppp_link *alink;
 2270                 struct timeval diff;
 2271                 int xmitBytes;
 2272 
 2273                 /* Start with base latency value */
 2274                 alink = &priv->links[priv->activeLinks[activeLinkNum]];
 2275                 latency[activeLinkNum] = alink->latency;
 2276                 sortByLatency[activeLinkNum] = activeLinkNum;   /* see below */
 2277 
 2278                 /* Any additional latency? */
 2279                 if (alink->bytesInQueue == 0)
 2280                         continue;
 2281 
 2282                 /* Compute time delta since last write */
 2283                 diff = now;
 2284                 timevalsub(&diff, &alink->lastWrite);
 2285                 
 2286                 /* alink->bytesInQueue will be changed, mark change time. */
 2287                 alink->lastWrite = now;
 2288 
 2289                 if (now.tv_sec < 0 || diff.tv_sec >= 10) {      /* sanity */
 2290                         alink->bytesInQueue = 0;
 2291                         continue;
 2292                 }
 2293 
 2294                 /* How many bytes could have transmitted since last write? */
 2295                 xmitBytes = (alink->conf.bandwidth * 10 * diff.tv_sec)
 2296                     + (alink->conf.bandwidth * (diff.tv_usec / 1000)) / 100;
 2297                 alink->bytesInQueue -= xmitBytes;
 2298                 if (alink->bytesInQueue < 0)
 2299                         alink->bytesInQueue = 0;
 2300                 else
 2301                         latency[activeLinkNum] +=
 2302                             (100 * alink->bytesInQueue) / alink->conf.bandwidth;
 2303         }
 2304 
 2305         /* Sort active links by latency */
 2306         qsort_r(sortByLatency,
 2307             priv->numActiveLinks, sizeof(*sortByLatency), latency, ng_ppp_intcmp);
 2308 
 2309         /* Find the interval we need (add links in sortByLatency[] order) */
 2310         for (numFragments = 1;
 2311             numFragments < priv->numActiveLinks; numFragments++) {
 2312                 for (total = i = 0; i < numFragments; i++) {
 2313                         int flowTime;
 2314 
 2315                         flowTime = latency[sortByLatency[numFragments]]
 2316                             - latency[sortByLatency[i]];
 2317                         total += ((flowTime * priv->links[
 2318                             priv->activeLinks[sortByLatency[i]]].conf.bandwidth)
 2319                                 + 99) / 100;
 2320                 }
 2321                 if (total >= len)
 2322                         break;
 2323         }
 2324 
 2325         /* Solve for t_0 in that interval */
 2326         for (topSum = botSum = i = 0; i < numFragments; i++) {
 2327                 int bw = priv->links[
 2328                     priv->activeLinks[sortByLatency[i]]].conf.bandwidth;
 2329 
 2330                 topSum += latency[sortByLatency[i]] * bw;       /* / 100 */
 2331                 botSum += bw;                                   /* / 100 */
 2332         }
 2333         t0 = ((len * 100) + topSum + botSum / 2) / botSum;
 2334 
 2335         /* Compute f_i(t_0) all i */
 2336         for (total = i = 0; i < numFragments; i++) {
 2337                 int bw = priv->links[
 2338                     priv->activeLinks[sortByLatency[i]]].conf.bandwidth;
 2339 
 2340                 distrib[sortByLatency[i]] =
 2341                     (bw * (t0 - latency[sortByLatency[i]]) + 50) / 100;
 2342                 total += distrib[sortByLatency[i]];
 2343         }
 2344 
 2345         /* Deal with any rounding error */
 2346         if (total < len) {
 2347                 struct ng_ppp_link *fastLink =
 2348                     &priv->links[priv->activeLinks[sortByLatency[0]]];
 2349                 int fast = 0;
 2350 
 2351                 /* Find the fastest link */
 2352                 for (i = 1; i < numFragments; i++) {
 2353                         struct ng_ppp_link *const link =
 2354                             &priv->links[priv->activeLinks[sortByLatency[i]]];
 2355 
 2356                         if (link->conf.bandwidth > fastLink->conf.bandwidth) {
 2357                                 fast = i;
 2358                                 fastLink = link;
 2359                         }
 2360                 }
 2361                 distrib[sortByLatency[fast]] += len - total;
 2362         } else while (total > len) {
 2363                 struct ng_ppp_link *slowLink =
 2364                     &priv->links[priv->activeLinks[sortByLatency[0]]];
 2365                 int delta, slow = 0;
 2366 
 2367                 /* Find the slowest link that still has bytes to remove */
 2368                 for (i = 1; i < numFragments; i++) {
 2369                         struct ng_ppp_link *const link =
 2370                             &priv->links[priv->activeLinks[sortByLatency[i]]];
 2371 
 2372                         if (distrib[sortByLatency[slow]] == 0
 2373                           || (distrib[sortByLatency[i]] > 0
 2374                             && link->conf.bandwidth <
 2375                               slowLink->conf.bandwidth)) {
 2376                                 slow = i;
 2377                                 slowLink = link;
 2378                         }
 2379                 }
 2380                 delta = total - len;
 2381                 if (delta > distrib[sortByLatency[slow]])
 2382                         delta = distrib[sortByLatency[slow]];
 2383                 distrib[sortByLatency[slow]] -= delta;
 2384                 total -= delta;
 2385         }
 2386 }
 2387 
 2388 /*
 2389  * Compare two integers
 2390  */
 2391 static int
 2392 ng_ppp_intcmp(void *latency, const void *v1, const void *v2)
 2393 {
 2394         const int index1 = *((const int *) v1);
 2395         const int index2 = *((const int *) v2);
 2396 
 2397         return ((int *)latency)[index1] - ((int *)latency)[index2];
 2398 }
 2399 
 2400 /*
 2401  * Prepend a possibly compressed PPP protocol number in front of a frame
 2402  */
 2403 static struct mbuf *
 2404 ng_ppp_addproto(struct mbuf *m, uint16_t proto, int compOK)
 2405 {
 2406         if (compOK && PROT_COMPRESSABLE(proto)) {
 2407                 uint8_t pbyte = (uint8_t)proto;
 2408 
 2409                 return ng_ppp_prepend(m, &pbyte, 1);
 2410         } else {
 2411                 uint16_t pword = htons((uint16_t)proto);
 2412 
 2413                 return ng_ppp_prepend(m, &pword, 2);
 2414         }
 2415 }
 2416 
 2417 /*
 2418  * Cut a possibly compressed PPP protocol number from the front of a frame.
 2419  */
 2420 static struct mbuf *
 2421 ng_ppp_cutproto(struct mbuf *m, uint16_t *proto)
 2422 {
 2423 
 2424         *proto = 0;
 2425         if (m->m_len < 1 && (m = m_pullup(m, 1)) == NULL)
 2426                 return (NULL);
 2427 
 2428         *proto = *mtod(m, uint8_t *);
 2429         m_adj(m, 1);
 2430 
 2431         if (!PROT_VALID(*proto)) {
 2432                 if (m->m_len < 1 && (m = m_pullup(m, 1)) == NULL)
 2433                         return (NULL);
 2434 
 2435                 *proto = (*proto << 8) + *mtod(m, uint8_t *);
 2436                 m_adj(m, 1);
 2437         }
 2438 
 2439         return (m);
 2440 }
 2441 
 2442 /*
 2443  * Prepend some bytes to an mbuf.
 2444  */
 2445 static struct mbuf *
 2446 ng_ppp_prepend(struct mbuf *m, const void *buf, int len)
 2447 {
 2448         M_PREPEND(m, len, M_DONTWAIT);
 2449         if (m == NULL || (m->m_len < len && (m = m_pullup(m, len)) == NULL))
 2450                 return (NULL);
 2451         bcopy(buf, mtod(m, uint8_t *), len);
 2452         return (m);
 2453 }
 2454 
 2455 /*
 2456  * Update private information that is derived from other private information
 2457  */
 2458 static void
 2459 ng_ppp_update(node_p node, int newConf)
 2460 {
 2461         const priv_p priv = NG_NODE_PRIVATE(node);
 2462         int i;
 2463 
 2464         /* Update active status for VJ Compression */
 2465         priv->vjCompHooked = priv->hooks[HOOK_INDEX_VJC_IP] != NULL
 2466             && priv->hooks[HOOK_INDEX_VJC_COMP] != NULL
 2467             && priv->hooks[HOOK_INDEX_VJC_UNCOMP] != NULL
 2468             && priv->hooks[HOOK_INDEX_VJC_VJIP] != NULL;
 2469 
 2470         /* Increase latency for each link an amount equal to one MP header */
 2471         if (newConf) {
 2472                 for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
 2473                         int hdrBytes;
 2474 
 2475                         if (priv->links[i].conf.bandwidth == 0)
 2476                             continue;
 2477                             
 2478                         hdrBytes = MP_AVERAGE_LINK_OVERHEAD
 2479                             + (priv->links[i].conf.enableACFComp ? 0 : 2)
 2480                             + (priv->links[i].conf.enableProtoComp ? 1 : 2)
 2481                             + (priv->conf.xmitShortSeq ? 2 : 4);
 2482                         priv->links[i].latency =
 2483                             priv->links[i].conf.latency +
 2484                             (hdrBytes / priv->links[i].conf.bandwidth + 50) / 100;
 2485                 }
 2486         }
 2487 
 2488         /* Update list of active links */
 2489         bzero(&priv->activeLinks, sizeof(priv->activeLinks));
 2490         priv->numActiveLinks = 0;
 2491         priv->allLinksEqual = 1;
 2492         for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
 2493                 struct ng_ppp_link *const link = &priv->links[i];
 2494 
 2495                 /* Is link active? */
 2496                 if (link->conf.enableLink && link->hook != NULL) {
 2497                         struct ng_ppp_link *link0;
 2498 
 2499                         /* Add link to list of active links */
 2500                         priv->activeLinks[priv->numActiveLinks++] = i;
 2501                         link0 = &priv->links[priv->activeLinks[0]];
 2502 
 2503                         /* Determine if all links are still equal */
 2504                         if (link->latency != link0->latency
 2505                           || link->conf.bandwidth != link0->conf.bandwidth)
 2506                                 priv->allLinksEqual = 0;
 2507 
 2508                         /* Initialize rec'd sequence number */
 2509                         if (link->seq == MP_NOSEQ) {
 2510                                 link->seq = (link == link0) ?
 2511                                     MP_INITIAL_SEQ : link0->seq;
 2512                         }
 2513                 } else
 2514                         link->seq = MP_NOSEQ;
 2515         }
 2516 
 2517         /* Update MP state as multi-link is active or not */
 2518         if (priv->conf.enableMultilink && priv->numActiveLinks > 0)
 2519                 ng_ppp_start_frag_timer(node);
 2520         else {
 2521                 ng_ppp_stop_frag_timer(node);
 2522                 ng_ppp_frag_reset(node);
 2523                 priv->xseq = MP_INITIAL_SEQ;
 2524                 priv->mseq = MP_INITIAL_SEQ;
 2525                 for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
 2526                         struct ng_ppp_link *const link = &priv->links[i];
 2527 
 2528                         bzero(&link->lastWrite, sizeof(link->lastWrite));
 2529                         link->bytesInQueue = 0;
 2530                         link->seq = MP_NOSEQ;
 2531                 }
 2532         }
 2533 }
 2534 
 2535 /*
 2536  * Determine if a new configuration would represent a valid change
 2537  * from the current configuration and link activity status.
 2538  */
 2539 static int
 2540 ng_ppp_config_valid(node_p node, const struct ng_ppp_node_conf *newConf)
 2541 {
 2542         const priv_p priv = NG_NODE_PRIVATE(node);
 2543         int i, newNumLinksActive;
 2544 
 2545         /* Check per-link config and count how many links would be active */
 2546         for (newNumLinksActive = i = 0; i < NG_PPP_MAX_LINKS; i++) {
 2547                 if (newConf->links[i].enableLink && priv->links[i].hook != NULL)
 2548                         newNumLinksActive++;
 2549                 if (!newConf->links[i].enableLink)
 2550                         continue;
 2551                 if (newConf->links[i].mru < MP_MIN_LINK_MRU)
 2552                         return (0);
 2553                 if (newConf->links[i].bandwidth == 0)
 2554                         return (0);
 2555                 if (newConf->links[i].bandwidth > NG_PPP_MAX_BANDWIDTH)
 2556                         return (0);
 2557                 if (newConf->links[i].latency > NG_PPP_MAX_LATENCY)
 2558                         return (0);
 2559         }
 2560 
 2561         /* Disallow changes to multi-link configuration while MP is active */
 2562         if (priv->numActiveLinks > 0 && newNumLinksActive > 0) {
 2563                 if (!priv->conf.enableMultilink
 2564                                 != !newConf->bund.enableMultilink
 2565                     || !priv->conf.xmitShortSeq != !newConf->bund.xmitShortSeq
 2566                     || !priv->conf.recvShortSeq != !newConf->bund.recvShortSeq)
 2567                         return (0);
 2568         }
 2569 
 2570         /* At most one link can be active unless multi-link is enabled */
 2571         if (!newConf->bund.enableMultilink && newNumLinksActive > 1)
 2572                 return (0);
 2573 
 2574         /* Configuration change would be valid */
 2575         return (1);
 2576 }
 2577 
 2578 /*
 2579  * Free all entries in the fragment queue
 2580  */
 2581 static void
 2582 ng_ppp_frag_reset(node_p node)
 2583 {
 2584         const priv_p priv = NG_NODE_PRIVATE(node);
 2585         struct ng_ppp_frag *qent, *qnext;
 2586 
 2587         for (qent = TAILQ_FIRST(&priv->frags); qent; qent = qnext) {
 2588                 qnext = TAILQ_NEXT(qent, f_qent);
 2589                 NG_FREE_M(qent->data);
 2590                 TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
 2591         }
 2592         TAILQ_INIT(&priv->frags);
 2593 }
 2594 
 2595 /*
 2596  * Start fragment queue timer
 2597  */
 2598 static void
 2599 ng_ppp_start_frag_timer(node_p node)
 2600 {
 2601         const priv_p priv = NG_NODE_PRIVATE(node);
 2602 
 2603         if (!(callout_pending(&priv->fragTimer)))
 2604                 ng_callout(&priv->fragTimer, node, NULL, MP_FRAGTIMER_INTERVAL,
 2605                     ng_ppp_frag_timeout, NULL, 0);
 2606 }
 2607 
 2608 /*
 2609  * Stop fragment queue timer
 2610  */
 2611 static void
 2612 ng_ppp_stop_frag_timer(node_p node)
 2613 {
 2614         const priv_p priv = NG_NODE_PRIVATE(node);
 2615 
 2616         if (callout_pending(&priv->fragTimer))
 2617                 ng_uncallout(&priv->fragTimer, node);
 2618 }

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