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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/8/sys/netgraph/ng_ppp.c 206661 2010-04-15 12:46:16Z 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 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_NOWAIT | M_ZERO);
  494         if (priv == NULL)
  495                 return (ENOMEM);
  496 
  497         NG_NODE_SET_PRIVATE(node, priv);
  498 
  499         /* Initialize state */
  500         TAILQ_INIT(&priv->frags);
  501         TAILQ_INIT(&priv->fragsfree);
  502         for (i = 0; i < MP_MAX_QUEUE_LEN; i++)
  503                 TAILQ_INSERT_TAIL(&priv->fragsfree, &priv->fragsmem[i], f_qent);
  504         for (i = 0; i < NG_PPP_MAX_LINKS; i++)
  505                 priv->links[i].seq = MP_NOSEQ;
  506         ng_callout_init(&priv->fragTimer);
  507 
  508         mtx_init(&priv->rmtx, "ng_ppp_recv", NULL, MTX_DEF);
  509         mtx_init(&priv->xmtx, "ng_ppp_xmit", NULL, MTX_DEF);
  510 
  511         /* Done */
  512         return (0);
  513 }
  514 
  515 /*
  516  * Give our OK for a hook to be added
  517  */
  518 static int
  519 ng_ppp_newhook(node_p node, hook_p hook, const char *name)
  520 {
  521         const priv_p priv = NG_NODE_PRIVATE(node);
  522         hook_p *hookPtr = NULL;
  523         int linkNum = -1;
  524         int hookIndex = -1;
  525 
  526         /* Figure out which hook it is */
  527         if (strncmp(name, NG_PPP_HOOK_LINK_PREFIX,      /* a link hook? */
  528             strlen(NG_PPP_HOOK_LINK_PREFIX)) == 0) {
  529                 const char *cp;
  530                 char *eptr;
  531 
  532                 cp = name + strlen(NG_PPP_HOOK_LINK_PREFIX);
  533                 if (!isdigit(*cp) || (cp[0] == '' && cp[1] != '\0'))
  534                         return (EINVAL);
  535                 linkNum = (int)strtoul(cp, &eptr, 10);
  536                 if (*eptr != '\0' || linkNum < 0 || linkNum >= NG_PPP_MAX_LINKS)
  537                         return (EINVAL);
  538                 hookPtr = &priv->links[linkNum].hook;
  539                 hookIndex = ~linkNum;
  540 
  541                 /* See if hook is already connected. */
  542                 if (*hookPtr != NULL)
  543                         return (EISCONN);
  544 
  545                 /* Disallow more than one link unless multilink is enabled. */
  546                 if (priv->links[linkNum].conf.enableLink &&
  547                     !priv->conf.enableMultilink && priv->numActiveLinks >= 1)
  548                         return (ENODEV);
  549 
  550         } else {                                /* must be a non-link hook */
  551                 int i;
  552 
  553                 for (i = 0; ng_ppp_hook_names[i].name != NULL; i++) {
  554                         if (strcmp(name, ng_ppp_hook_names[i].name) == 0) {
  555                                 hookPtr = &priv->hooks[i];
  556                                 hookIndex = i;
  557                                 break;
  558                         }
  559                 }
  560                 if (ng_ppp_hook_names[i].name == NULL)
  561                         return (EINVAL);        /* no such hook */
  562 
  563                 /* See if hook is already connected */
  564                 if (*hookPtr != NULL)
  565                         return (EISCONN);
  566 
  567                 /* Every non-linkX hook have it's own function. */
  568                 NG_HOOK_SET_RCVDATA(hook, ng_ppp_hook_names[i].fn);
  569         }
  570 
  571         /* OK */
  572         *hookPtr = hook;
  573         NG_HOOK_SET_PRIVATE(hook, (void *)(intptr_t)hookIndex);
  574         ng_ppp_update(node, 0);
  575         return (0);
  576 }
  577 
  578 /*
  579  * Receive a control message
  580  */
  581 static int
  582 ng_ppp_rcvmsg(node_p node, item_p item, hook_p lasthook)
  583 {
  584         const priv_p priv = NG_NODE_PRIVATE(node);
  585         struct ng_mesg *resp = NULL;
  586         int error = 0;
  587         struct ng_mesg *msg;
  588 
  589         NGI_GET_MSG(item, msg);
  590         switch (msg->header.typecookie) {
  591         case NGM_PPP_COOKIE:
  592                 switch (msg->header.cmd) {
  593                 case NGM_PPP_SET_CONFIG:
  594                     {
  595                         struct ng_ppp_node_conf *const conf =
  596                             (struct ng_ppp_node_conf *)msg->data;
  597                         int i;
  598 
  599                         /* Check for invalid or illegal config */
  600                         if (msg->header.arglen != sizeof(*conf))
  601                                 ERROUT(EINVAL);
  602                         if (!ng_ppp_config_valid(node, conf))
  603                                 ERROUT(EINVAL);
  604 
  605                         /* Copy config */
  606                         priv->conf = conf->bund;
  607                         for (i = 0; i < NG_PPP_MAX_LINKS; i++)
  608                                 priv->links[i].conf = conf->links[i];
  609                         ng_ppp_update(node, 1);
  610                         break;
  611                     }
  612                 case NGM_PPP_GET_CONFIG:
  613                     {
  614                         struct ng_ppp_node_conf *conf;
  615                         int i;
  616 
  617                         NG_MKRESPONSE(resp, msg, sizeof(*conf), M_NOWAIT);
  618                         if (resp == NULL)
  619                                 ERROUT(ENOMEM);
  620                         conf = (struct ng_ppp_node_conf *)resp->data;
  621                         conf->bund = priv->conf;
  622                         for (i = 0; i < NG_PPP_MAX_LINKS; i++)
  623                                 conf->links[i] = priv->links[i].conf;
  624                         break;
  625                     }
  626                 case NGM_PPP_GET_MP_STATE:
  627                     {
  628                         struct ng_ppp_mp_state *info;
  629                         int i;
  630 
  631                         NG_MKRESPONSE(resp, msg, sizeof(*info), M_NOWAIT);
  632                         if (resp == NULL)
  633                                 ERROUT(ENOMEM);
  634                         info = (struct ng_ppp_mp_state *)resp->data;
  635                         bzero(info, sizeof(*info));
  636                         for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
  637                                 if (priv->links[i].seq != MP_NOSEQ)
  638                                         info->rseq[i] = priv->links[i].seq;
  639                         }
  640                         info->mseq = priv->mseq;
  641                         info->xseq = priv->xseq;
  642                         break;
  643                     }
  644                 case NGM_PPP_GET_LINK_STATS:
  645                 case NGM_PPP_CLR_LINK_STATS:
  646                 case NGM_PPP_GETCLR_LINK_STATS:
  647                 case NGM_PPP_GET_LINK_STATS64:
  648                 case NGM_PPP_GETCLR_LINK_STATS64:
  649                     {
  650                         struct ng_ppp_link_stat64 *stats;
  651                         uint16_t linkNum;
  652 
  653                         /* Process request. */
  654                         if (msg->header.arglen != sizeof(uint16_t))
  655                                 ERROUT(EINVAL);
  656                         linkNum = *((uint16_t *) msg->data);
  657                         if (linkNum >= NG_PPP_MAX_LINKS
  658                             && linkNum != NG_PPP_BUNDLE_LINKNUM)
  659                                 ERROUT(EINVAL);
  660                         stats = (linkNum == NG_PPP_BUNDLE_LINKNUM) ?
  661                             &priv->bundleStats : &priv->links[linkNum].stats;
  662 
  663                         /* Make 64bit reply. */
  664                         if (msg->header.cmd == NGM_PPP_GET_LINK_STATS64 || 
  665                             msg->header.cmd == NGM_PPP_GETCLR_LINK_STATS64) {
  666                                 NG_MKRESPONSE(resp, msg,
  667                                     sizeof(struct ng_ppp_link_stat64), M_NOWAIT);
  668                                 if (resp == NULL)
  669                                         ERROUT(ENOMEM);
  670                                 bcopy(stats, resp->data, sizeof(*stats));
  671                         } else
  672                         /* Make 32bit reply. */
  673                         if (msg->header.cmd == NGM_PPP_GET_LINK_STATS || 
  674                             msg->header.cmd == NGM_PPP_GETCLR_LINK_STATS) {
  675                                 struct ng_ppp_link_stat *rs;
  676                                 NG_MKRESPONSE(resp, msg,
  677                                     sizeof(struct ng_ppp_link_stat), M_NOWAIT);
  678                                 if (resp == NULL)
  679                                         ERROUT(ENOMEM);
  680                                 rs = (struct ng_ppp_link_stat *)resp->data;
  681                                 /* Truncate 64->32 bits. */
  682                                 rs->xmitFrames = stats->xmitFrames;
  683                                 rs->xmitOctets = stats->xmitOctets;
  684                                 rs->recvFrames = stats->recvFrames;
  685                                 rs->recvOctets = stats->recvOctets;
  686                                 rs->badProtos = stats->badProtos;
  687                                 rs->runts = stats->runts;
  688                                 rs->dupFragments = stats->dupFragments;
  689                                 rs->dropFragments = stats->dropFragments;
  690                         }
  691                         /* Clear stats. */
  692                         if (msg->header.cmd != NGM_PPP_GET_LINK_STATS &&
  693                             msg->header.cmd != NGM_PPP_GET_LINK_STATS64)
  694                                 bzero(stats, sizeof(*stats));
  695                         break;
  696                     }
  697                 default:
  698                         error = EINVAL;
  699                         break;
  700                 }
  701                 break;
  702         case NGM_VJC_COOKIE:
  703             {
  704                 /*
  705                  * Forward it to the vjc node. leave the
  706                  * old return address alone.
  707                  * If we have no hook, let NG_RESPOND_MSG
  708                  * clean up any remaining resources.
  709                  * Because we have no resp, the item will be freed
  710                  * along with anything it references. Don't
  711                  * let msg be freed twice.
  712                  */
  713                 NGI_MSG(item) = msg;    /* put it back in the item */
  714                 msg = NULL;
  715                 if ((lasthook = priv->hooks[HOOK_INDEX_VJC_IP])) {
  716                         NG_FWD_ITEM_HOOK(error, item, lasthook);
  717                 }
  718                 return (error);
  719             }
  720         default:
  721                 error = EINVAL;
  722                 break;
  723         }
  724 done:
  725         NG_RESPOND_MSG(error, node, item, resp);
  726         NG_FREE_MSG(msg);
  727         return (error);
  728 }
  729 
  730 /*
  731  * Destroy node
  732  */
  733 static int
  734 ng_ppp_shutdown(node_p node)
  735 {
  736         const priv_p priv = NG_NODE_PRIVATE(node);
  737 
  738         /* Stop fragment queue timer */
  739         ng_ppp_stop_frag_timer(node);
  740 
  741         /* Take down netgraph node */
  742         ng_ppp_frag_reset(node);
  743         mtx_destroy(&priv->rmtx);
  744         mtx_destroy(&priv->xmtx);
  745         bzero(priv, sizeof(*priv));
  746         free(priv, M_NETGRAPH_PPP);
  747         NG_NODE_SET_PRIVATE(node, NULL);
  748         NG_NODE_UNREF(node);            /* let the node escape */
  749         return (0);
  750 }
  751 
  752 /*
  753  * Hook disconnection
  754  */
  755 static int
  756 ng_ppp_disconnect(hook_p hook)
  757 {
  758         const node_p node = NG_HOOK_NODE(hook);
  759         const priv_p priv = NG_NODE_PRIVATE(node);
  760         const int index = (intptr_t)NG_HOOK_PRIVATE(hook);
  761 
  762         /* Zero out hook pointer */
  763         if (index < 0)
  764                 priv->links[~index].hook = NULL;
  765         else
  766                 priv->hooks[index] = NULL;
  767 
  768         /* Update derived info (or go away if no hooks left). */
  769         if (NG_NODE_NUMHOOKS(node) > 0)
  770                 ng_ppp_update(node, 0);
  771         else if (NG_NODE_IS_VALID(node))
  772                 ng_rmnode_self(node);
  773 
  774         return (0);
  775 }
  776 
  777 /*
  778  * Proto layer
  779  */
  780 
  781 /*
  782  * Receive data on a hook inet.
  783  */
  784 static int
  785 ng_ppp_rcvdata_inet(hook_p hook, item_p item)
  786 {
  787         const node_p node = NG_HOOK_NODE(hook);
  788         const priv_p priv = NG_NODE_PRIVATE(node);
  789 
  790         if (!priv->conf.enableIP) {
  791                 NG_FREE_ITEM(item);
  792                 return (ENXIO);
  793         }
  794         return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_IP));
  795 }
  796 
  797 /*
  798  * Receive data on a hook ipv6.
  799  */
  800 static int
  801 ng_ppp_rcvdata_ipv6(hook_p hook, item_p item)
  802 {
  803         const node_p node = NG_HOOK_NODE(hook);
  804         const priv_p priv = NG_NODE_PRIVATE(node);
  805 
  806         if (!priv->conf.enableIPv6) {
  807                 NG_FREE_ITEM(item);
  808                 return (ENXIO);
  809         }
  810         return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_IPV6));
  811 }
  812 
  813 /*
  814  * Receive data on a hook atalk.
  815  */
  816 static int
  817 ng_ppp_rcvdata_atalk(hook_p hook, item_p item)
  818 {
  819         const node_p node = NG_HOOK_NODE(hook);
  820         const priv_p priv = NG_NODE_PRIVATE(node);
  821 
  822         if (!priv->conf.enableAtalk) {
  823                 NG_FREE_ITEM(item);
  824                 return (ENXIO);
  825         }
  826         return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_ATALK));
  827 }
  828 
  829 /*
  830  * Receive data on a hook ipx
  831  */
  832 static int
  833 ng_ppp_rcvdata_ipx(hook_p hook, item_p item)
  834 {
  835         const node_p node = NG_HOOK_NODE(hook);
  836         const priv_p priv = NG_NODE_PRIVATE(node);
  837 
  838         if (!priv->conf.enableIPX) {
  839                 NG_FREE_ITEM(item);
  840                 return (ENXIO);
  841         }
  842         return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_IPX));
  843 }
  844 
  845 /*
  846  * Receive data on a hook bypass
  847  */
  848 static int
  849 ng_ppp_rcvdata_bypass(hook_p hook, item_p item)
  850 {
  851         uint16_t linkNum;
  852         uint16_t proto;
  853         struct mbuf *m;
  854 
  855         NGI_GET_M(item, m);
  856         if (m->m_pkthdr.len < 4) {
  857                 NG_FREE_ITEM(item);
  858                 return (EINVAL);
  859         }
  860         if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
  861                 NG_FREE_ITEM(item);
  862                 return (ENOBUFS);
  863         }
  864         linkNum = be16dec(mtod(m, uint8_t *));
  865         proto = be16dec(mtod(m, uint8_t *) + 2);
  866         m_adj(m, 4);
  867         NGI_M(item) = m;
  868 
  869         if (linkNum == NG_PPP_BUNDLE_LINKNUM)
  870                 return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, proto));
  871         else
  872                 return (ng_ppp_link_xmit(NG_HOOK_NODE(hook), item, proto,
  873                     linkNum, 0));
  874 }
  875 
  876 static int
  877 ng_ppp_bypass(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
  878 {
  879         const priv_p priv = NG_NODE_PRIVATE(node);
  880         uint16_t hdr[2];
  881         struct mbuf *m;
  882         int error;
  883 
  884         if (priv->hooks[HOOK_INDEX_BYPASS] == NULL) {
  885             NG_FREE_ITEM(item);
  886             return (ENXIO);
  887         }
  888 
  889         /* Add 4-byte bypass header. */
  890         hdr[0] = htons(linkNum);
  891         hdr[1] = htons(proto);
  892 
  893         NGI_GET_M(item, m);
  894         if ((m = ng_ppp_prepend(m, &hdr, 4)) == NULL) {
  895                 NG_FREE_ITEM(item);
  896                 return (ENOBUFS);
  897         }
  898         NGI_M(item) = m;
  899 
  900         /* Send packet out hook. */
  901         NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_BYPASS]);
  902         return (error);
  903 }
  904 
  905 static int
  906 ng_ppp_proto_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
  907 {
  908         const priv_p priv = NG_NODE_PRIVATE(node);
  909         hook_p outHook = NULL;
  910         int error;
  911 #ifdef ALIGNED_POINTER
  912         struct mbuf *m, *n;
  913 
  914         NGI_GET_M(item, m);
  915         if (!ALIGNED_POINTER(mtod(m, caddr_t), uint32_t)) {
  916                 n = m_defrag(m, M_NOWAIT);
  917                 if (n == NULL) {
  918                         m_freem(m);
  919                         NG_FREE_ITEM(item);
  920                         return (ENOBUFS);
  921                 }
  922                 m = n;
  923         }
  924         NGI_M(item) = m;
  925 #endif /* ALIGNED_POINTER */
  926         switch (proto) {
  927             case PROT_IP:
  928                 if (priv->conf.enableIP)
  929                     outHook = priv->hooks[HOOK_INDEX_INET];
  930                 break;
  931             case PROT_IPV6:
  932                 if (priv->conf.enableIPv6)
  933                     outHook = priv->hooks[HOOK_INDEX_IPV6];
  934                 break;
  935             case PROT_ATALK:
  936                 if (priv->conf.enableAtalk)
  937                     outHook = priv->hooks[HOOK_INDEX_ATALK];
  938                 break;
  939             case PROT_IPX:
  940                 if (priv->conf.enableIPX)
  941                     outHook = priv->hooks[HOOK_INDEX_IPX];
  942                 break;
  943         }
  944 
  945         if (outHook == NULL)
  946                 return (ng_ppp_bypass(node, item, proto, linkNum));
  947 
  948         /* Send packet out hook. */
  949         NG_FWD_ITEM_HOOK(error, item, outHook);
  950         return (error);
  951 }
  952 
  953 /*
  954  * Header compression layer
  955  */
  956 
  957 static int
  958 ng_ppp_hcomp_xmit(node_p node, item_p item, uint16_t proto)
  959 {
  960         const priv_p priv = NG_NODE_PRIVATE(node);
  961 
  962         if (proto == PROT_IP &&
  963             priv->conf.enableVJCompression &&
  964             priv->vjCompHooked) {
  965                 int error;
  966 
  967                 /* Send packet out hook. */
  968                 NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_VJC_IP]);
  969                 return (error);
  970         }
  971 
  972         return (ng_ppp_comp_xmit(node, item, proto));
  973 }
  974 
  975 /*
  976  * Receive data on a hook vjc_comp.
  977  */
  978 static int
  979 ng_ppp_rcvdata_vjc_comp(hook_p hook, item_p item)
  980 {
  981         const node_p node = NG_HOOK_NODE(hook);
  982         const priv_p priv = NG_NODE_PRIVATE(node);
  983 
  984         if (!priv->conf.enableVJCompression) {
  985                 NG_FREE_ITEM(item);
  986                 return (ENXIO);
  987         }
  988         return (ng_ppp_comp_xmit(node, item, PROT_VJCOMP));
  989 }
  990 
  991 /*
  992  * Receive data on a hook vjc_uncomp.
  993  */
  994 static int
  995 ng_ppp_rcvdata_vjc_uncomp(hook_p hook, item_p item)
  996 {
  997         const node_p node = NG_HOOK_NODE(hook);
  998         const priv_p priv = NG_NODE_PRIVATE(node);
  999 
 1000         if (!priv->conf.enableVJCompression) {
 1001                 NG_FREE_ITEM(item);
 1002                 return (ENXIO);
 1003         }
 1004         return (ng_ppp_comp_xmit(node, item, PROT_VJUNCOMP));
 1005 }
 1006 
 1007 /*
 1008  * Receive data on a hook vjc_vjip.
 1009  */
 1010 static int
 1011 ng_ppp_rcvdata_vjc_vjip(hook_p hook, item_p item)
 1012 {
 1013         const node_p node = NG_HOOK_NODE(hook);
 1014         const priv_p priv = NG_NODE_PRIVATE(node);
 1015 
 1016         if (!priv->conf.enableVJCompression) {
 1017                 NG_FREE_ITEM(item);
 1018                 return (ENXIO);
 1019         }
 1020         return (ng_ppp_comp_xmit(node, item, PROT_IP));
 1021 }
 1022 
 1023 static int
 1024 ng_ppp_hcomp_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
 1025 {
 1026         const priv_p priv = NG_NODE_PRIVATE(node);
 1027 
 1028         if (priv->conf.enableVJDecompression && priv->vjCompHooked) {
 1029                 hook_p outHook = NULL;
 1030 
 1031                 switch (proto) {
 1032                     case PROT_VJCOMP:
 1033                         outHook = priv->hooks[HOOK_INDEX_VJC_COMP];
 1034                         break;
 1035                     case PROT_VJUNCOMP:
 1036                         outHook = priv->hooks[HOOK_INDEX_VJC_UNCOMP];
 1037                         break;
 1038                 }
 1039 
 1040                 if (outHook) {
 1041                         int error;
 1042 
 1043                         /* Send packet out hook. */
 1044                         NG_FWD_ITEM_HOOK(error, item, outHook);
 1045                         return (error);
 1046                 }
 1047         }
 1048 
 1049         return (ng_ppp_proto_recv(node, item, proto, linkNum));
 1050 }
 1051 
 1052 /*
 1053  * Receive data on a hook vjc_ip.
 1054  */
 1055 static int
 1056 ng_ppp_rcvdata_vjc_ip(hook_p hook, item_p item)
 1057 {
 1058         const node_p node = NG_HOOK_NODE(hook);
 1059         const priv_p priv = NG_NODE_PRIVATE(node);
 1060 
 1061         if (!priv->conf.enableVJDecompression) {
 1062                 NG_FREE_ITEM(item);
 1063                 return (ENXIO);
 1064         }
 1065         return (ng_ppp_proto_recv(node, item, PROT_IP, NG_PPP_BUNDLE_LINKNUM));
 1066 }
 1067 
 1068 /*
 1069  * Compression layer
 1070  */
 1071 
 1072 static int
 1073 ng_ppp_comp_xmit(node_p node, item_p item, uint16_t proto)
 1074 {
 1075         const priv_p priv = NG_NODE_PRIVATE(node);
 1076 
 1077         if (priv->conf.enableCompression &&
 1078             proto < 0x4000 &&
 1079             proto != PROT_COMPD &&
 1080             proto != PROT_CRYPTD &&
 1081             priv->hooks[HOOK_INDEX_COMPRESS] != NULL) {
 1082                 struct mbuf *m;
 1083                 int error;
 1084 
 1085                 NGI_GET_M(item, m);
 1086                 if ((m = ng_ppp_addproto(m, proto, 0)) == NULL) {
 1087                         NG_FREE_ITEM(item);
 1088                         return (ENOBUFS);
 1089                 }
 1090                 NGI_M(item) = m;
 1091 
 1092                 /* Send packet out hook. */
 1093                 NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_COMPRESS]);
 1094                 return (error);
 1095         }
 1096 
 1097         return (ng_ppp_crypt_xmit(node, item, proto));
 1098 }
 1099 
 1100 /*
 1101  * Receive data on a hook compress.
 1102  */
 1103 static int
 1104 ng_ppp_rcvdata_compress(hook_p hook, item_p item)
 1105 {
 1106         const node_p node = NG_HOOK_NODE(hook);
 1107         const priv_p priv = NG_NODE_PRIVATE(node);
 1108         uint16_t proto;
 1109 
 1110         switch (priv->conf.enableCompression) {
 1111             case NG_PPP_COMPRESS_NONE:
 1112                 NG_FREE_ITEM(item);
 1113                 return (ENXIO);
 1114             case NG_PPP_COMPRESS_FULL:
 1115                 {
 1116                         struct mbuf *m;
 1117 
 1118                         NGI_GET_M(item, m);
 1119                         if ((m = ng_ppp_cutproto(m, &proto)) == NULL) {
 1120                                 NG_FREE_ITEM(item);
 1121                                 return (EIO);
 1122                         }
 1123                         NGI_M(item) = m;
 1124                         if (!PROT_VALID(proto)) {
 1125                                 NG_FREE_ITEM(item);
 1126                                 return (EIO);
 1127                         }
 1128                 }
 1129                 break;
 1130             default:
 1131                 proto = PROT_COMPD;
 1132                 break;
 1133         }
 1134         return (ng_ppp_crypt_xmit(node, item, proto));
 1135 }
 1136 
 1137 static int
 1138 ng_ppp_comp_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
 1139 {
 1140         const priv_p priv = NG_NODE_PRIVATE(node);
 1141 
 1142         if (proto < 0x4000 &&
 1143             ((proto == PROT_COMPD && priv->conf.enableDecompression) ||
 1144             priv->conf.enableDecompression == NG_PPP_DECOMPRESS_FULL) &&
 1145             priv->hooks[HOOK_INDEX_DECOMPRESS] != NULL) {
 1146                 int error;
 1147 
 1148                 if (priv->conf.enableDecompression == NG_PPP_DECOMPRESS_FULL) {
 1149                         struct mbuf *m;
 1150                         NGI_GET_M(item, m);
 1151                         if ((m = ng_ppp_addproto(m, proto, 0)) == NULL) {
 1152                                 NG_FREE_ITEM(item);
 1153                                 return (EIO);
 1154                         }
 1155                         NGI_M(item) = m;
 1156                 }
 1157 
 1158                 /* Send packet out hook. */
 1159                 NG_FWD_ITEM_HOOK(error, item,
 1160                     priv->hooks[HOOK_INDEX_DECOMPRESS]);
 1161                 return (error);
 1162         } else if (proto == PROT_COMPD) {
 1163                 /* Disabled protos MUST be silently discarded, but
 1164                  * unsupported MUST not. Let user-level decide this. */
 1165                 return (ng_ppp_bypass(node, item, proto, linkNum));
 1166         }
 1167 
 1168         return (ng_ppp_hcomp_recv(node, item, proto, linkNum));
 1169 }
 1170 
 1171 /*
 1172  * Receive data on a hook decompress.
 1173  */
 1174 static int
 1175 ng_ppp_rcvdata_decompress(hook_p hook, item_p item)
 1176 {
 1177         const node_p node = NG_HOOK_NODE(hook);
 1178         const priv_p priv = NG_NODE_PRIVATE(node);
 1179         uint16_t proto;
 1180         struct mbuf *m;
 1181 
 1182         if (!priv->conf.enableDecompression) {
 1183                 NG_FREE_ITEM(item);
 1184                 return (ENXIO);
 1185         }
 1186         NGI_GET_M(item, m);
 1187         if ((m = ng_ppp_cutproto(m, &proto)) == NULL) {
 1188                 NG_FREE_ITEM(item);
 1189                 return (EIO);
 1190         }
 1191         NGI_M(item) = m;
 1192         if (!PROT_VALID(proto)) {
 1193                 priv->bundleStats.badProtos++;
 1194                 NG_FREE_ITEM(item);
 1195                 return (EIO);
 1196         }
 1197         return (ng_ppp_hcomp_recv(node, item, proto, NG_PPP_BUNDLE_LINKNUM));
 1198 }
 1199 
 1200 /*
 1201  * Encryption layer
 1202  */
 1203 
 1204 static int
 1205 ng_ppp_crypt_xmit(node_p node, item_p item, uint16_t proto)
 1206 {
 1207         const priv_p priv = NG_NODE_PRIVATE(node);
 1208 
 1209         if (priv->conf.enableEncryption &&
 1210             proto < 0x4000 &&
 1211             proto != PROT_CRYPTD &&
 1212             priv->hooks[HOOK_INDEX_ENCRYPT] != NULL) {
 1213                 struct mbuf *m;
 1214                 int error;
 1215 
 1216                 NGI_GET_M(item, m);
 1217                 if ((m = ng_ppp_addproto(m, proto, 0)) == NULL) {
 1218                         NG_FREE_ITEM(item);
 1219                         return (ENOBUFS);
 1220                 }
 1221                 NGI_M(item) = m;
 1222 
 1223                 /* Send packet out hook. */
 1224                 NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_ENCRYPT]);
 1225                 return (error);
 1226         }
 1227 
 1228         return (ng_ppp_mp_xmit(node, item, proto));
 1229 }
 1230 
 1231 /*
 1232  * Receive data on a hook encrypt.
 1233  */
 1234 static int
 1235 ng_ppp_rcvdata_encrypt(hook_p hook, item_p item)
 1236 {
 1237         const node_p node = NG_HOOK_NODE(hook);
 1238         const priv_p priv = NG_NODE_PRIVATE(node);
 1239 
 1240         if (!priv->conf.enableEncryption) {
 1241                 NG_FREE_ITEM(item);
 1242                 return (ENXIO);
 1243         }
 1244         return (ng_ppp_mp_xmit(node, item, PROT_CRYPTD));
 1245 }
 1246 
 1247 static int
 1248 ng_ppp_crypt_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
 1249 {
 1250         const priv_p priv = NG_NODE_PRIVATE(node);
 1251 
 1252         if (proto == PROT_CRYPTD) {
 1253                 if (priv->conf.enableDecryption &&
 1254                     priv->hooks[HOOK_INDEX_DECRYPT] != NULL) {
 1255                         int error;
 1256 
 1257                         /* Send packet out hook. */
 1258                         NG_FWD_ITEM_HOOK(error, item,
 1259                             priv->hooks[HOOK_INDEX_DECRYPT]);
 1260                         return (error);
 1261                 } else {
 1262                         /* Disabled protos MUST be silently discarded, but
 1263                          * unsupported MUST not. Let user-level decide this. */
 1264                         return (ng_ppp_bypass(node, item, proto, linkNum));
 1265                 }
 1266         }
 1267 
 1268         return (ng_ppp_comp_recv(node, item, proto, linkNum));
 1269 }
 1270 
 1271 /*
 1272  * Receive data on a hook decrypt.
 1273  */
 1274 static int
 1275 ng_ppp_rcvdata_decrypt(hook_p hook, item_p item)
 1276 {
 1277         const node_p node = NG_HOOK_NODE(hook);
 1278         const priv_p priv = NG_NODE_PRIVATE(node);
 1279         uint16_t proto;
 1280         struct mbuf *m;
 1281 
 1282         if (!priv->conf.enableDecryption) {
 1283                 NG_FREE_ITEM(item);
 1284                 return (ENXIO);
 1285         }
 1286         NGI_GET_M(item, m);
 1287         if ((m = ng_ppp_cutproto(m, &proto)) == NULL) {
 1288                 NG_FREE_ITEM(item);
 1289                 return (EIO);
 1290         }
 1291         NGI_M(item) = m;
 1292         if (!PROT_VALID(proto)) {
 1293                 priv->bundleStats.badProtos++;
 1294                 NG_FREE_ITEM(item);
 1295                 return (EIO);
 1296         }
 1297         return (ng_ppp_comp_recv(node, item, proto, NG_PPP_BUNDLE_LINKNUM));
 1298 }
 1299 
 1300 /*
 1301  * Link layer
 1302  */
 1303 
 1304 static int
 1305 ng_ppp_link_xmit(node_p node, item_p item, uint16_t proto, uint16_t linkNum, int plen)
 1306 {
 1307         const priv_p priv = NG_NODE_PRIVATE(node);
 1308         struct ng_ppp_link *link;
 1309         int len, error;
 1310         struct mbuf *m;
 1311         uint16_t mru;
 1312 
 1313         /* Check if link correct. */
 1314         if (linkNum >= NG_PPP_MAX_LINKS) {
 1315                 ERROUT(ENETDOWN);
 1316         }
 1317 
 1318         /* Get link pointer (optimization). */
 1319         link = &priv->links[linkNum];
 1320 
 1321         /* Check link status (if real). */
 1322         if (link->hook == NULL) {
 1323                 ERROUT(ENETDOWN);
 1324         }
 1325 
 1326         /* Extract mbuf. */
 1327         NGI_GET_M(item, m);
 1328 
 1329         /* Check peer's MRU for this link. */
 1330         mru = link->conf.mru;
 1331         if (mru != 0 && m->m_pkthdr.len > mru) {
 1332                 NG_FREE_M(m);
 1333                 ERROUT(EMSGSIZE);
 1334         }
 1335 
 1336         /* Prepend protocol number, possibly compressed. */
 1337         if ((m = ng_ppp_addproto(m, proto, link->conf.enableProtoComp)) ==
 1338             NULL) {
 1339                 ERROUT(ENOBUFS);
 1340         }
 1341 
 1342         /* Prepend address and control field (unless compressed). */
 1343         if (proto == PROT_LCP || !link->conf.enableACFComp) {
 1344                 if ((m = ng_ppp_prepend(m, &ng_ppp_acf, 2)) == NULL)
 1345                         ERROUT(ENOBUFS);
 1346         }
 1347 
 1348         /* Deliver frame. */
 1349         len = m->m_pkthdr.len;
 1350         NG_FWD_NEW_DATA(error, item, link->hook, m);
 1351 
 1352         mtx_lock(&priv->xmtx);
 1353 
 1354         /* Update link stats. */
 1355         link->stats.xmitFrames++;
 1356         link->stats.xmitOctets += len;
 1357 
 1358         /* Update bundle stats. */
 1359         if (plen > 0) {
 1360             priv->bundleStats.xmitFrames++;
 1361             priv->bundleStats.xmitOctets += plen;
 1362         }
 1363 
 1364         /* Update 'bytes in queue' counter. */
 1365         if (error == 0) {
 1366                 /* bytesInQueue and lastWrite required only for mp_strategy. */
 1367                 if (priv->conf.enableMultilink && !priv->allLinksEqual &&
 1368                     !priv->conf.enableRoundRobin) {
 1369                         /* If queue was empty, then mark this time. */
 1370                         if (link->bytesInQueue == 0)
 1371                                 getmicrouptime(&link->lastWrite);
 1372                         link->bytesInQueue += len + MP_AVERAGE_LINK_OVERHEAD;
 1373                         /* Limit max queue length to 50 pkts. BW can be defined
 1374                            incorrectly and link may not signal overload. */
 1375                         if (link->bytesInQueue > 50 * 1600)
 1376                                 link->bytesInQueue = 50 * 1600;
 1377                 }
 1378         }
 1379         mtx_unlock(&priv->xmtx);
 1380         return (error);
 1381 
 1382 done:
 1383         NG_FREE_ITEM(item);
 1384         return (error);
 1385 }
 1386 
 1387 /*
 1388  * Receive data on a hook linkX.
 1389  */
 1390 static int
 1391 ng_ppp_rcvdata(hook_p hook, item_p item)
 1392 {
 1393         const node_p node = NG_HOOK_NODE(hook);
 1394         const priv_p priv = NG_NODE_PRIVATE(node);
 1395         const int index = (intptr_t)NG_HOOK_PRIVATE(hook);
 1396         const uint16_t linkNum = (uint16_t)~index;
 1397         struct ng_ppp_link * const link = &priv->links[linkNum];
 1398         uint16_t proto;
 1399         struct mbuf *m;
 1400         int error = 0;
 1401 
 1402         KASSERT(linkNum < NG_PPP_MAX_LINKS,
 1403             ("%s: bogus index 0x%x", __func__, index));
 1404 
 1405         NGI_GET_M(item, m);
 1406 
 1407         mtx_lock(&priv->rmtx);
 1408 
 1409         /* Stats */
 1410         link->stats.recvFrames++;
 1411         link->stats.recvOctets += m->m_pkthdr.len;
 1412 
 1413         /* Strip address and control fields, if present. */
 1414         if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL)
 1415                 ERROUT(ENOBUFS);
 1416         if (mtod(m, uint8_t *)[0] == 0xff &&
 1417             mtod(m, uint8_t *)[1] == 0x03)
 1418                 m_adj(m, 2);
 1419 
 1420         /* Get protocol number */
 1421         if ((m = ng_ppp_cutproto(m, &proto)) == NULL)
 1422                 ERROUT(ENOBUFS);
 1423         NGI_M(item) = m;        /* Put changed m back into item. */
 1424 
 1425         if (!PROT_VALID(proto)) {
 1426                 link->stats.badProtos++;
 1427                 ERROUT(EIO);
 1428         }
 1429 
 1430         /* LCP packets must go directly to bypass. */
 1431         if (proto >= 0xB000) {
 1432                 mtx_unlock(&priv->rmtx);
 1433                 return (ng_ppp_bypass(node, item, proto, linkNum));
 1434         }
 1435         
 1436         /* Other packets are denied on a disabled link. */
 1437         if (!link->conf.enableLink)
 1438                 ERROUT(ENXIO);
 1439 
 1440         /* Proceed to multilink layer. Mutex will be unlocked inside. */
 1441         error = ng_ppp_mp_recv(node, item, proto, linkNum);
 1442         mtx_assert(&priv->rmtx, MA_NOTOWNED);
 1443         return (error);
 1444 
 1445 done:
 1446         mtx_unlock(&priv->rmtx);
 1447         NG_FREE_ITEM(item);
 1448         return (error);
 1449 }
 1450 
 1451 /*
 1452  * Multilink layer
 1453  */
 1454 
 1455 /*
 1456  * Handle an incoming multi-link fragment
 1457  *
 1458  * The fragment reassembly algorithm is somewhat complex. This is mainly
 1459  * because we are required not to reorder the reconstructed packets, yet
 1460  * fragments are only guaranteed to arrive in order on a per-link basis.
 1461  * In other words, when we have a complete packet ready, but the previous
 1462  * packet is still incomplete, we have to decide between delivering the
 1463  * complete packet and throwing away the incomplete one, or waiting to
 1464  * see if the remainder of the incomplete one arrives, at which time we
 1465  * can deliver both packets, in order.
 1466  *
 1467  * This problem is exacerbated by "sequence number slew", which is when
 1468  * the sequence numbers coming in from different links are far apart from
 1469  * each other. In particular, certain unnamed equipment (*cough* Ascend)
 1470  * has been seen to generate sequence number slew of up to 10 on an ISDN
 1471  * 2B-channel MP link. There is nothing invalid about sequence number slew
 1472  * but it makes the reasssembly process have to work harder.
 1473  *
 1474  * However, the peer is required to transmit fragments in order on each
 1475  * link. That means if we define MSEQ as the minimum over all links of
 1476  * the highest sequence number received on that link, then we can always
 1477  * give up any hope of receiving a fragment with sequence number < MSEQ in
 1478  * the future (all of this using 'wraparound' sequence number space).
 1479  * Therefore we can always immediately throw away incomplete packets
 1480  * missing fragments with sequence numbers < MSEQ.
 1481  *
 1482  * Here is an overview of our algorithm:
 1483  *
 1484  *    o Received fragments are inserted into a queue, for which we
 1485  *      maintain these invariants between calls to this function:
 1486  *
 1487  *      - Fragments are ordered in the queue by sequence number
 1488  *      - If a complete packet is at the head of the queue, then
 1489  *        the first fragment in the packet has seq# > MSEQ + 1
 1490  *        (otherwise, we could deliver it immediately)
 1491  *      - If any fragments have seq# < MSEQ, then they are necessarily
 1492  *        part of a packet whose missing seq#'s are all > MSEQ (otherwise,
 1493  *        we can throw them away because they'll never be completed)
 1494  *      - The queue contains at most MP_MAX_QUEUE_LEN fragments
 1495  *
 1496  *    o We have a periodic timer that checks the queue for the first
 1497  *      complete packet that has been sitting in the queue "too long".
 1498  *      When one is detected, all previous (incomplete) fragments are
 1499  *      discarded, their missing fragments are declared lost and MSEQ
 1500  *      is increased.
 1501  *
 1502  *    o If we recieve a fragment with seq# < MSEQ, we throw it away
 1503  *      because we've already delcared it lost.
 1504  *
 1505  * This assumes linkNum != NG_PPP_BUNDLE_LINKNUM.
 1506  */
 1507 static int
 1508 ng_ppp_mp_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
 1509 {
 1510         const priv_p priv = NG_NODE_PRIVATE(node);
 1511         struct ng_ppp_link *const link = &priv->links[linkNum];
 1512         struct ng_ppp_frag *frag;
 1513         struct ng_ppp_frag *qent;
 1514         int i, diff, inserted;
 1515         struct mbuf *m;
 1516         int     error = 0;
 1517 
 1518         if ((!priv->conf.enableMultilink) || proto != PROT_MP) {
 1519                 /* Stats */
 1520                 priv->bundleStats.recvFrames++;
 1521                 priv->bundleStats.recvOctets += NGI_M(item)->m_pkthdr.len;
 1522 
 1523                 mtx_unlock(&priv->rmtx);
 1524                 return (ng_ppp_crypt_recv(node, item, proto, linkNum));
 1525         }
 1526 
 1527         NGI_GET_M(item, m);
 1528 
 1529         /* Get a new frag struct from the free queue */
 1530         if ((frag = TAILQ_FIRST(&priv->fragsfree)) == NULL) {
 1531                 printf("No free fragments headers in ng_ppp!\n");
 1532                 NG_FREE_M(m);
 1533                 goto process;
 1534         }
 1535 
 1536         /* Extract fragment information from MP header */
 1537         if (priv->conf.recvShortSeq) {
 1538                 uint16_t shdr;
 1539 
 1540                 if (m->m_pkthdr.len < 2) {
 1541                         link->stats.runts++;
 1542                         NG_FREE_M(m);
 1543                         ERROUT(EINVAL);
 1544                 }
 1545                 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL)
 1546                         ERROUT(ENOBUFS);
 1547 
 1548                 shdr = be16dec(mtod(m, void *));
 1549                 frag->seq = MP_SHORT_EXTEND(shdr);
 1550                 frag->first = (shdr & MP_SHORT_FIRST_FLAG) != 0;
 1551                 frag->last = (shdr & MP_SHORT_LAST_FLAG) != 0;
 1552                 diff = MP_SHORT_SEQ_DIFF(frag->seq, priv->mseq);
 1553                 m_adj(m, 2);
 1554         } else {
 1555                 uint32_t lhdr;
 1556 
 1557                 if (m->m_pkthdr.len < 4) {
 1558                         link->stats.runts++;
 1559                         NG_FREE_M(m);
 1560                         ERROUT(EINVAL);
 1561                 }
 1562                 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL)
 1563                         ERROUT(ENOBUFS);
 1564 
 1565                 lhdr = be32dec(mtod(m, void *));
 1566                 frag->seq = MP_LONG_EXTEND(lhdr);
 1567                 frag->first = (lhdr & MP_LONG_FIRST_FLAG) != 0;
 1568                 frag->last = (lhdr & MP_LONG_LAST_FLAG) != 0;
 1569                 diff = MP_LONG_SEQ_DIFF(frag->seq, priv->mseq);
 1570                 m_adj(m, 4);
 1571         }
 1572         frag->data = m;
 1573         getmicrouptime(&frag->timestamp);
 1574 
 1575         /* If sequence number is < MSEQ, we've already declared this
 1576            fragment as lost, so we have no choice now but to drop it */
 1577         if (diff < 0) {
 1578                 link->stats.dropFragments++;
 1579                 NG_FREE_M(m);
 1580                 ERROUT(0);
 1581         }
 1582 
 1583         /* Update highest received sequence number on this link and MSEQ */
 1584         priv->mseq = link->seq = frag->seq;
 1585         for (i = 0; i < priv->numActiveLinks; i++) {
 1586                 struct ng_ppp_link *const alink =
 1587                     &priv->links[priv->activeLinks[i]];
 1588 
 1589                 if (MP_RECV_SEQ_DIFF(priv, alink->seq, priv->mseq) < 0)
 1590                         priv->mseq = alink->seq;
 1591         }
 1592 
 1593         /* Remove frag struct from free queue. */
 1594         TAILQ_REMOVE(&priv->fragsfree, frag, f_qent);
 1595 
 1596         /* Add fragment to queue, which is sorted by sequence number */
 1597         inserted = 0;
 1598         TAILQ_FOREACH_REVERSE(qent, &priv->frags, ng_ppp_fraglist, f_qent) {
 1599                 diff = MP_RECV_SEQ_DIFF(priv, frag->seq, qent->seq);
 1600                 if (diff > 0) {
 1601                         TAILQ_INSERT_AFTER(&priv->frags, qent, frag, f_qent);
 1602                         inserted = 1;
 1603                         break;
 1604                 } else if (diff == 0) {      /* should never happen! */
 1605                         link->stats.dupFragments++;
 1606                         NG_FREE_M(frag->data);
 1607                         TAILQ_INSERT_HEAD(&priv->fragsfree, frag, f_qent);
 1608                         ERROUT(EINVAL);
 1609                 }
 1610         }
 1611         if (!inserted)
 1612                 TAILQ_INSERT_HEAD(&priv->frags, frag, f_qent);
 1613 
 1614 process:
 1615         /* Process the queue */
 1616         /* NOTE: rmtx will be unlocked for sending time! */
 1617         error = ng_ppp_frag_process(node, item);
 1618         mtx_unlock(&priv->rmtx);
 1619         return (error);
 1620 
 1621 done:
 1622         mtx_unlock(&priv->rmtx);
 1623         NG_FREE_ITEM(item);
 1624         return (error);
 1625 }
 1626 
 1627 /************************************************************************
 1628                         HELPER STUFF
 1629  ************************************************************************/
 1630 
 1631 /*
 1632  * If new mseq > current then set it and update all active links
 1633  */
 1634 static void
 1635 ng_ppp_bump_mseq(node_p node, int32_t new_mseq)
 1636 {
 1637         const priv_p priv = NG_NODE_PRIVATE(node);
 1638         int i;
 1639         
 1640         if (MP_RECV_SEQ_DIFF(priv, priv->mseq, new_mseq) < 0) {
 1641                 priv->mseq = new_mseq;
 1642                 for (i = 0; i < priv->numActiveLinks; i++) {
 1643                         struct ng_ppp_link *const alink =
 1644                             &priv->links[priv->activeLinks[i]];
 1645 
 1646                         if (MP_RECV_SEQ_DIFF(priv,
 1647                             alink->seq, new_mseq) < 0)
 1648                                 alink->seq = new_mseq;
 1649                 }
 1650         }
 1651 }
 1652 
 1653 /*
 1654  * Examine our list of fragments, and determine if there is a
 1655  * complete and deliverable packet at the head of the list.
 1656  * Return 1 if so, zero otherwise.
 1657  */
 1658 static int
 1659 ng_ppp_check_packet(node_p node)
 1660 {
 1661         const priv_p priv = NG_NODE_PRIVATE(node);
 1662         struct ng_ppp_frag *qent, *qnext;
 1663 
 1664         /* Check for empty queue */
 1665         if (TAILQ_EMPTY(&priv->frags))
 1666                 return (0);
 1667 
 1668         /* Check first fragment is the start of a deliverable packet */
 1669         qent = TAILQ_FIRST(&priv->frags);
 1670         if (!qent->first || MP_RECV_SEQ_DIFF(priv, qent->seq, priv->mseq) > 1)
 1671                 return (0);
 1672 
 1673         /* Check that all the fragments are there */
 1674         while (!qent->last) {
 1675                 qnext = TAILQ_NEXT(qent, f_qent);
 1676                 if (qnext == NULL)      /* end of queue */
 1677                         return (0);
 1678                 if (qnext->seq != MP_NEXT_RECV_SEQ(priv, qent->seq))
 1679                         return (0);
 1680                 qent = qnext;
 1681         }
 1682 
 1683         /* Got one */
 1684         return (1);
 1685 }
 1686 
 1687 /*
 1688  * Pull a completed packet off the head of the incoming fragment queue.
 1689  * This assumes there is a completed packet there to pull off.
 1690  */
 1691 static void
 1692 ng_ppp_get_packet(node_p node, struct mbuf **mp)
 1693 {
 1694         const priv_p priv = NG_NODE_PRIVATE(node);
 1695         struct ng_ppp_frag *qent, *qnext;
 1696         struct mbuf *m = NULL, *tail;
 1697 
 1698         qent = TAILQ_FIRST(&priv->frags);
 1699         KASSERT(!TAILQ_EMPTY(&priv->frags) && qent->first,
 1700             ("%s: no packet", __func__));
 1701         for (tail = NULL; qent != NULL; qent = qnext) {
 1702                 qnext = TAILQ_NEXT(qent, f_qent);
 1703                 KASSERT(!TAILQ_EMPTY(&priv->frags),
 1704                     ("%s: empty q", __func__));
 1705                 TAILQ_REMOVE(&priv->frags, qent, f_qent);
 1706                 if (tail == NULL)
 1707                         tail = m = qent->data;
 1708                 else {
 1709                         m->m_pkthdr.len += qent->data->m_pkthdr.len;
 1710                         tail->m_next = qent->data;
 1711                 }
 1712                 while (tail->m_next != NULL)
 1713                         tail = tail->m_next;
 1714                 if (qent->last) {
 1715                         qnext = NULL;
 1716                         /* Bump MSEQ if necessary */
 1717                         ng_ppp_bump_mseq(node, qent->seq);
 1718                 }
 1719                 TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
 1720         }
 1721         *mp = m;
 1722 }
 1723 
 1724 /*
 1725  * Trim fragments from the queue whose packets can never be completed.
 1726  * This assumes a complete packet is NOT at the beginning of the queue.
 1727  * Returns 1 if fragments were removed, zero otherwise.
 1728  */
 1729 static int
 1730 ng_ppp_frag_trim(node_p node)
 1731 {
 1732         const priv_p priv = NG_NODE_PRIVATE(node);
 1733         struct ng_ppp_frag *qent, *qnext = NULL;
 1734         int removed = 0;
 1735 
 1736         /* Scan for "dead" fragments and remove them */
 1737         while (1) {
 1738                 int dead = 0;
 1739 
 1740                 /* If queue is empty, we're done */
 1741                 if (TAILQ_EMPTY(&priv->frags))
 1742                         break;
 1743 
 1744                 /* Determine whether first fragment can ever be completed */
 1745                 TAILQ_FOREACH(qent, &priv->frags, f_qent) {
 1746                         if (MP_RECV_SEQ_DIFF(priv, qent->seq, priv->mseq) >= 0)
 1747                                 break;
 1748                         qnext = TAILQ_NEXT(qent, f_qent);
 1749                         KASSERT(qnext != NULL,
 1750                             ("%s: last frag < MSEQ?", __func__));
 1751                         if (qnext->seq != MP_NEXT_RECV_SEQ(priv, qent->seq)
 1752                             || qent->last || qnext->first) {
 1753                                 dead = 1;
 1754                                 break;
 1755                         }
 1756                 }
 1757                 if (!dead)
 1758                         break;
 1759 
 1760                 /* Remove fragment and all others in the same packet */
 1761                 while ((qent = TAILQ_FIRST(&priv->frags)) != qnext) {
 1762                         KASSERT(!TAILQ_EMPTY(&priv->frags),
 1763                             ("%s: empty q", __func__));
 1764                         priv->bundleStats.dropFragments++;
 1765                         TAILQ_REMOVE(&priv->frags, qent, f_qent);
 1766                         NG_FREE_M(qent->data);
 1767                         TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
 1768                         removed = 1;
 1769                 }
 1770         }
 1771         return (removed);
 1772 }
 1773 
 1774 /*
 1775  * Drop fragments on queue overflow.
 1776  * Returns 1 if fragments were removed, zero otherwise.
 1777  */
 1778 static int
 1779 ng_ppp_frag_drop(node_p node)
 1780 {
 1781         const priv_p priv = NG_NODE_PRIVATE(node);
 1782 
 1783         /* Check queue length */
 1784         if (TAILQ_EMPTY(&priv->fragsfree)) {
 1785                 struct ng_ppp_frag *qent;
 1786 
 1787                 /* Get oldest fragment */
 1788                 KASSERT(!TAILQ_EMPTY(&priv->frags),
 1789                     ("%s: empty q", __func__));
 1790                 qent = TAILQ_FIRST(&priv->frags);
 1791 
 1792                 /* Bump MSEQ if necessary */
 1793                 ng_ppp_bump_mseq(node, qent->seq);
 1794 
 1795                 /* Drop it */
 1796                 priv->bundleStats.dropFragments++;
 1797                 TAILQ_REMOVE(&priv->frags, qent, f_qent);
 1798                 NG_FREE_M(qent->data);
 1799                 TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
 1800 
 1801                 return (1);
 1802         }
 1803         return (0);
 1804 }
 1805 
 1806 /*
 1807  * Run the queue, restoring the queue invariants
 1808  */
 1809 static int
 1810 ng_ppp_frag_process(node_p node, item_p oitem)
 1811 {
 1812         const priv_p priv = NG_NODE_PRIVATE(node);
 1813         struct mbuf *m;
 1814         item_p item;
 1815         uint16_t proto;
 1816 
 1817         do {
 1818                 /* Deliver any deliverable packets */
 1819                 while (ng_ppp_check_packet(node)) {
 1820                         ng_ppp_get_packet(node, &m);
 1821                         if ((m = ng_ppp_cutproto(m, &proto)) == NULL)
 1822                                 continue;
 1823                         if (!PROT_VALID(proto)) {
 1824                                 priv->bundleStats.badProtos++;
 1825                                 NG_FREE_M(m);
 1826                                 continue;
 1827                         }
 1828                         if (oitem) { /* If original item present - reuse it. */
 1829                                 item = oitem;
 1830                                 oitem = NULL;
 1831                                 NGI_M(item) = m;
 1832                         } else {
 1833                                 item = ng_package_data(m, NG_NOFLAGS);
 1834                         }
 1835                         if (item != NULL) {
 1836                                 /* Stats */
 1837                                 priv->bundleStats.recvFrames++;
 1838                                 priv->bundleStats.recvOctets += 
 1839                                     NGI_M(item)->m_pkthdr.len;
 1840 
 1841                                 /* Drop mutex for the sending time.
 1842                                  * Priv may change, but we are ready!
 1843                                  */
 1844                                 mtx_unlock(&priv->rmtx);
 1845                                 ng_ppp_crypt_recv(node, item, proto,
 1846                                         NG_PPP_BUNDLE_LINKNUM);
 1847                                 mtx_lock(&priv->rmtx);
 1848                         }
 1849                 }
 1850           /* Delete dead fragments and try again */
 1851         } while (ng_ppp_frag_trim(node) || ng_ppp_frag_drop(node));
 1852         
 1853         /* If we haven't reused original item - free it. */
 1854         if (oitem) NG_FREE_ITEM(oitem);
 1855 
 1856         /* Done */
 1857         return (0);
 1858 }
 1859 
 1860 /*
 1861  * Check for 'stale' completed packets that need to be delivered
 1862  *
 1863  * If a link goes down or has a temporary failure, MSEQ can get
 1864  * "stuck", because no new incoming fragments appear on that link.
 1865  * This can cause completed packets to never get delivered if
 1866  * their sequence numbers are all > MSEQ + 1.
 1867  *
 1868  * This routine checks how long all of the completed packets have
 1869  * been sitting in the queue, and if too long, removes fragments
 1870  * from the queue and increments MSEQ to allow them to be delivered.
 1871  */
 1872 static void
 1873 ng_ppp_frag_checkstale(node_p node)
 1874 {
 1875         const priv_p priv = NG_NODE_PRIVATE(node);
 1876         struct ng_ppp_frag *qent, *beg, *end;
 1877         struct timeval now, age;
 1878         struct mbuf *m;
 1879         int seq;
 1880         item_p item;
 1881         int endseq;
 1882         uint16_t proto;
 1883 
 1884         now.tv_sec = 0;                 /* uninitialized state */
 1885         while (1) {
 1886 
 1887                 /* If queue is empty, we're done */
 1888                 if (TAILQ_EMPTY(&priv->frags))
 1889                         break;
 1890 
 1891                 /* Find the first complete packet in the queue */
 1892                 beg = end = NULL;
 1893                 seq = TAILQ_FIRST(&priv->frags)->seq;
 1894                 TAILQ_FOREACH(qent, &priv->frags, f_qent) {
 1895                         if (qent->first)
 1896                                 beg = qent;
 1897                         else if (qent->seq != seq)
 1898                                 beg = NULL;
 1899                         if (beg != NULL && qent->last) {
 1900                                 end = qent;
 1901                                 break;
 1902                         }
 1903                         seq = MP_NEXT_RECV_SEQ(priv, seq);
 1904                 }
 1905 
 1906                 /* If none found, exit */
 1907                 if (end == NULL)
 1908                         break;
 1909 
 1910                 /* Get current time (we assume we've been up for >= 1 second) */
 1911                 if (now.tv_sec == 0)
 1912                         getmicrouptime(&now);
 1913 
 1914                 /* Check if packet has been queued too long */
 1915                 age = now;
 1916                 timevalsub(&age, &beg->timestamp);
 1917                 if (timevalcmp(&age, &ng_ppp_max_staleness, < ))
 1918                         break;
 1919 
 1920                 /* Throw away junk fragments in front of the completed packet */
 1921                 while ((qent = TAILQ_FIRST(&priv->frags)) != beg) {
 1922                         KASSERT(!TAILQ_EMPTY(&priv->frags),
 1923                             ("%s: empty q", __func__));
 1924                         priv->bundleStats.dropFragments++;
 1925                         TAILQ_REMOVE(&priv->frags, qent, f_qent);
 1926                         NG_FREE_M(qent->data);
 1927                         TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
 1928                 }
 1929 
 1930                 /* Extract completed packet */
 1931                 endseq = end->seq;
 1932                 ng_ppp_get_packet(node, &m);
 1933 
 1934                 if ((m = ng_ppp_cutproto(m, &proto)) == NULL)
 1935                         continue;
 1936                 if (!PROT_VALID(proto)) {
 1937                         priv->bundleStats.badProtos++;
 1938                         NG_FREE_M(m);
 1939                         continue;
 1940                 }
 1941 
 1942                 /* Deliver packet */
 1943                 if ((item = ng_package_data(m, NG_NOFLAGS)) != NULL) {
 1944                         /* Stats */
 1945                         priv->bundleStats.recvFrames++;
 1946                         priv->bundleStats.recvOctets += NGI_M(item)->m_pkthdr.len;
 1947 
 1948                         ng_ppp_crypt_recv(node, item, proto,
 1949                                 NG_PPP_BUNDLE_LINKNUM);
 1950                 }
 1951         }
 1952 }
 1953 
 1954 /*
 1955  * Periodically call ng_ppp_frag_checkstale()
 1956  */
 1957 static void
 1958 ng_ppp_frag_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 1959 {
 1960         /* XXX: is this needed? */
 1961         if (NG_NODE_NOT_VALID(node))
 1962                 return;
 1963 
 1964         /* Scan the fragment queue */
 1965         ng_ppp_frag_checkstale(node);
 1966 
 1967         /* Start timer again */
 1968         ng_ppp_start_frag_timer(node);
 1969 }
 1970 
 1971 /*
 1972  * Deliver a frame out on the bundle, i.e., figure out how to fragment
 1973  * the frame across the individual PPP links and do so.
 1974  */
 1975 static int
 1976 ng_ppp_mp_xmit(node_p node, item_p item, uint16_t proto)
 1977 {
 1978         const priv_p priv = NG_NODE_PRIVATE(node);
 1979         const int hdr_len = priv->conf.xmitShortSeq ? 2 : 4;
 1980         int distrib[NG_PPP_MAX_LINKS];
 1981         int firstFragment;
 1982         int activeLinkNum;
 1983         struct mbuf *m;
 1984         int     plen;
 1985         int     frags;
 1986         int32_t seq;
 1987 
 1988         /* At least one link must be active */
 1989         if (priv->numActiveLinks == 0) {
 1990                 NG_FREE_ITEM(item);
 1991                 return (ENETDOWN);
 1992         }
 1993         
 1994         /* Save length for later stats. */
 1995         plen = NGI_M(item)->m_pkthdr.len;
 1996 
 1997         if (!priv->conf.enableMultilink) {
 1998                 return (ng_ppp_link_xmit(node, item, proto,
 1999                     priv->activeLinks[0], plen));
 2000         }
 2001 
 2002         /* Check peer's MRRU for this bundle. */
 2003         if (plen > priv->conf.mrru) {
 2004                 NG_FREE_ITEM(item);
 2005                 return (EMSGSIZE);
 2006         }
 2007 
 2008         /* Extract mbuf. */
 2009         NGI_GET_M(item, m);
 2010 
 2011         /* Prepend protocol number, possibly compressed. */
 2012         if ((m = ng_ppp_addproto(m, proto, 1)) == NULL) {
 2013                 NG_FREE_ITEM(item);
 2014                 return (ENOBUFS);
 2015         }
 2016 
 2017         /* Clear distribution plan */
 2018         bzero(&distrib, priv->numActiveLinks * sizeof(distrib[0]));
 2019 
 2020         mtx_lock(&priv->xmtx);
 2021 
 2022         /* Round-robin strategy */
 2023         if (priv->conf.enableRoundRobin) {
 2024                 activeLinkNum = priv->lastLink++ % priv->numActiveLinks;
 2025                 distrib[activeLinkNum] = m->m_pkthdr.len;
 2026                 goto deliver;
 2027         }
 2028 
 2029         /* Strategy when all links are equivalent (optimize the common case) */
 2030         if (priv->allLinksEqual) {
 2031                 int     numFrags, fraction, remain;
 2032                 int     i;
 2033                 
 2034                 /* Calculate optimal fragment count */
 2035                 numFrags = priv->numActiveLinks;
 2036                 if (numFrags > m->m_pkthdr.len / MP_MIN_FRAG_LEN)
 2037                     numFrags = m->m_pkthdr.len / MP_MIN_FRAG_LEN;
 2038                 if (numFrags == 0)
 2039                     numFrags = 1;
 2040 
 2041                 fraction = m->m_pkthdr.len / numFrags;
 2042                 remain = m->m_pkthdr.len - (fraction * numFrags);
 2043                 
 2044                 /* Assign distribution */
 2045                 for (i = 0; i < numFrags; i++) {
 2046                         distrib[priv->lastLink++ % priv->numActiveLinks]
 2047                             = fraction + (((remain--) > 0)?1:0);
 2048                 }
 2049                 goto deliver;
 2050         }
 2051 
 2052         /* Strategy when all links are not equivalent */
 2053         ng_ppp_mp_strategy(node, m->m_pkthdr.len, distrib);
 2054 
 2055 deliver:
 2056         /* Estimate fragments count */
 2057         frags = 0;
 2058         for (activeLinkNum = priv->numActiveLinks - 1;
 2059             activeLinkNum >= 0; activeLinkNum--) {
 2060                 const uint16_t linkNum = priv->activeLinks[activeLinkNum];
 2061                 struct ng_ppp_link *const link = &priv->links[linkNum];
 2062                 
 2063                 frags += (distrib[activeLinkNum] + link->conf.mru - hdr_len - 1) /
 2064                     (link->conf.mru - hdr_len);
 2065         }
 2066         
 2067         /* Get out initial sequence number */
 2068         seq = priv->xseq;
 2069 
 2070         /* Update next sequence number */
 2071         if (priv->conf.xmitShortSeq) {
 2072             priv->xseq = (seq + frags) & MP_SHORT_SEQ_MASK;
 2073         } else {
 2074             priv->xseq = (seq + frags) & MP_LONG_SEQ_MASK;
 2075         }
 2076 
 2077         mtx_unlock(&priv->xmtx);
 2078 
 2079         /* Send alloted portions of frame out on the link(s) */
 2080         for (firstFragment = 1, activeLinkNum = priv->numActiveLinks - 1;
 2081             activeLinkNum >= 0; activeLinkNum--) {
 2082                 const uint16_t linkNum = priv->activeLinks[activeLinkNum];
 2083                 struct ng_ppp_link *const link = &priv->links[linkNum];
 2084 
 2085                 /* Deliver fragment(s) out the next link */
 2086                 for ( ; distrib[activeLinkNum] > 0; firstFragment = 0) {
 2087                         int len, lastFragment, error;
 2088                         struct mbuf *m2;
 2089 
 2090                         /* Calculate fragment length; don't exceed link MTU */
 2091                         len = distrib[activeLinkNum];
 2092                         if (len > link->conf.mru - hdr_len)
 2093                                 len = link->conf.mru - hdr_len;
 2094                         distrib[activeLinkNum] -= len;
 2095                         lastFragment = (len == m->m_pkthdr.len);
 2096 
 2097                         /* Split off next fragment as "m2" */
 2098                         m2 = m;
 2099                         if (!lastFragment) {
 2100                                 struct mbuf *n = m_split(m, len, M_DONTWAIT);
 2101 
 2102                                 if (n == NULL) {
 2103                                         NG_FREE_M(m);
 2104                                         if (firstFragment)
 2105                                                 NG_FREE_ITEM(item);
 2106                                         return (ENOMEM);
 2107                                 }
 2108                                 m_tag_copy_chain(n, m, M_DONTWAIT);
 2109                                 m = n;
 2110                         }
 2111 
 2112                         /* Prepend MP header */
 2113                         if (priv->conf.xmitShortSeq) {
 2114                                 uint16_t shdr;
 2115 
 2116                                 shdr = seq;
 2117                                 seq = (seq + 1) & MP_SHORT_SEQ_MASK;
 2118                                 if (firstFragment)
 2119                                         shdr |= MP_SHORT_FIRST_FLAG;
 2120                                 if (lastFragment)
 2121                                         shdr |= MP_SHORT_LAST_FLAG;
 2122                                 shdr = htons(shdr);
 2123                                 m2 = ng_ppp_prepend(m2, &shdr, 2);
 2124                         } else {
 2125                                 uint32_t lhdr;
 2126 
 2127                                 lhdr = seq;
 2128                                 seq = (seq + 1) & MP_LONG_SEQ_MASK;
 2129                                 if (firstFragment)
 2130                                         lhdr |= MP_LONG_FIRST_FLAG;
 2131                                 if (lastFragment)
 2132                                         lhdr |= MP_LONG_LAST_FLAG;
 2133                                 lhdr = htonl(lhdr);
 2134                                 m2 = ng_ppp_prepend(m2, &lhdr, 4);
 2135                         }
 2136                         if (m2 == NULL) {
 2137                                 if (!lastFragment)
 2138                                         m_freem(m);
 2139                                 if (firstFragment)
 2140                                         NG_FREE_ITEM(item);
 2141                                 return (ENOBUFS);
 2142                         }
 2143 
 2144                         /* Send fragment */
 2145                         if (firstFragment) {
 2146                                 NGI_M(item) = m2; /* Reuse original item. */
 2147                         } else {
 2148                                 item = ng_package_data(m2, NG_NOFLAGS);
 2149                         }
 2150                         if (item != NULL) {
 2151                                 error = ng_ppp_link_xmit(node, item, PROT_MP,
 2152                                             linkNum, (firstFragment?plen:0));
 2153                                 if (error != 0) {
 2154                                         if (!lastFragment)
 2155                                                 NG_FREE_M(m);
 2156                                         return (error);
 2157                                 }
 2158                         }
 2159                 }
 2160         }
 2161 
 2162         /* Done */
 2163         return (0);
 2164 }
 2165 
 2166 /*
 2167  * Computing the optimal fragmentation
 2168  * -----------------------------------
 2169  *
 2170  * This routine tries to compute the optimal fragmentation pattern based
 2171  * on each link's latency, bandwidth, and calculated additional latency.
 2172  * The latter quantity is the additional latency caused by previously
 2173  * written data that has not been transmitted yet.
 2174  *
 2175  * This algorithm is only useful when not all of the links have the
 2176  * same latency and bandwidth values.
 2177  *
 2178  * The essential idea is to make the last bit of each fragment of the
 2179  * frame arrive at the opposite end at the exact same time. This greedy
 2180  * algorithm is optimal, in that no other scheduling could result in any
 2181  * packet arriving any sooner unless packets are delivered out of order.
 2182  *
 2183  * Suppose link i has bandwidth b_i (in tens of bytes per milisecond) and
 2184  * latency l_i (in miliseconds). Consider the function function f_i(t)
 2185  * which is equal to the number of bytes that will have arrived at
 2186  * the peer after t miliseconds if we start writing continuously at
 2187  * time t = 0. Then f_i(t) = b_i * (t - l_i) = ((b_i * t) - (l_i * b_i).
 2188  * That is, f_i(t) is a line with slope b_i and y-intersect -(l_i * b_i).
 2189  * Note that the y-intersect is always <= zero because latency can't be
 2190  * negative.  Note also that really the function is f_i(t) except when
 2191  * f_i(t) is negative, in which case the function is zero.  To take
 2192  * care of this, let Q_i(t) = { if (f_i(t) > 0) return 1; else return 0; }.
 2193  * So the actual number of bytes that will have arrived at the peer after
 2194  * t miliseconds is f_i(t) * Q_i(t).
 2195  *
 2196  * At any given time, each link has some additional latency a_i >= 0
 2197  * due to previously written fragment(s) which are still in the queue.
 2198  * This value is easily computed from the time since last transmission,
 2199  * the previous latency value, the number of bytes written, and the
 2200  * link's bandwidth.
 2201  *
 2202  * Assume that l_i includes any a_i already, and that the links are
 2203  * sorted by latency, so that l_i <= l_{i+1}.
 2204  *
 2205  * Let N be the total number of bytes in the current frame we are sending.
 2206  *
 2207  * Suppose we were to start writing bytes at time t = 0 on all links
 2208  * simultaneously, which is the most we can possibly do.  Then let
 2209  * F(t) be equal to the total number of bytes received by the peer
 2210  * after t miliseconds. Then F(t) = Sum_i (f_i(t) * Q_i(t)).
 2211  *
 2212  * Our goal is simply this: fragment the frame across the links such
 2213  * that the peer is able to reconstruct the completed frame as soon as
 2214  * possible, i.e., at the least possible value of t. Call this value t_0.
 2215  *
 2216  * Then it follows that F(t_0) = N. Our strategy is first to find the value
 2217  * of t_0, and then deduce how many bytes to write to each link.
 2218  *
 2219  * Rewriting F(t_0):
 2220  *
 2221  *   t_0 = ( N + Sum_i ( l_i * b_i * Q_i(t_0) ) ) / Sum_i ( b_i * Q_i(t_0) )
 2222  *
 2223  * Now, we note that Q_i(t) is constant for l_i <= t <= l_{i+1}. t_0 will
 2224  * lie in one of these ranges.  To find it, we just need to find the i such
 2225  * that F(l_i) <= N <= F(l_{i+1}).  Then we compute all the constant values
 2226  * for Q_i() in this range, plug in the remaining values, solving for t_0.
 2227  *
 2228  * Once t_0 is known, then the number of bytes to send on link i is
 2229  * just f_i(t_0) * Q_i(t_0).
 2230  *
 2231  * In other words, we start allocating bytes to the links one at a time.
 2232  * We keep adding links until the frame is completely sent.  Some links
 2233  * may not get any bytes because their latency is too high.
 2234  *
 2235  * Is all this work really worth the trouble?  Depends on the situation.
 2236  * The bigger the ratio of computer speed to link speed, and the more
 2237  * important total bundle latency is (e.g., for interactive response time),
 2238  * the more it's worth it.  There is however the cost of calling this
 2239  * function for every frame.  The running time is O(n^2) where n is the
 2240  * number of links that receive a non-zero number of bytes.
 2241  *
 2242  * Since latency is measured in miliseconds, the "resolution" of this
 2243  * algorithm is one milisecond.
 2244  *
 2245  * To avoid this algorithm altogether, configure all links to have the
 2246  * same latency and bandwidth.
 2247  */
 2248 static void
 2249 ng_ppp_mp_strategy(node_p node, int len, int *distrib)
 2250 {
 2251         const priv_p priv = NG_NODE_PRIVATE(node);
 2252         int latency[NG_PPP_MAX_LINKS];
 2253         int sortByLatency[NG_PPP_MAX_LINKS];
 2254         int activeLinkNum;
 2255         int t0, total, topSum, botSum;
 2256         struct timeval now;
 2257         int i, numFragments;
 2258 
 2259         /* If only one link, this gets real easy */
 2260         if (priv->numActiveLinks == 1) {
 2261                 distrib[0] = len;
 2262                 return;
 2263         }
 2264 
 2265         /* Get current time */
 2266         getmicrouptime(&now);
 2267 
 2268         /* Compute latencies for each link at this point in time */
 2269         for (activeLinkNum = 0;
 2270             activeLinkNum < priv->numActiveLinks; activeLinkNum++) {
 2271                 struct ng_ppp_link *alink;
 2272                 struct timeval diff;
 2273                 int xmitBytes;
 2274 
 2275                 /* Start with base latency value */
 2276                 alink = &priv->links[priv->activeLinks[activeLinkNum]];
 2277                 latency[activeLinkNum] = alink->latency;
 2278                 sortByLatency[activeLinkNum] = activeLinkNum;   /* see below */
 2279 
 2280                 /* Any additional latency? */
 2281                 if (alink->bytesInQueue == 0)
 2282                         continue;
 2283 
 2284                 /* Compute time delta since last write */
 2285                 diff = now;
 2286                 timevalsub(&diff, &alink->lastWrite);
 2287                 
 2288                 /* alink->bytesInQueue will be changed, mark change time. */
 2289                 alink->lastWrite = now;
 2290 
 2291                 if (now.tv_sec < 0 || diff.tv_sec >= 10) {      /* sanity */
 2292                         alink->bytesInQueue = 0;
 2293                         continue;
 2294                 }
 2295 
 2296                 /* How many bytes could have transmitted since last write? */
 2297                 xmitBytes = (alink->conf.bandwidth * 10 * diff.tv_sec)
 2298                     + (alink->conf.bandwidth * (diff.tv_usec / 1000)) / 100;
 2299                 alink->bytesInQueue -= xmitBytes;
 2300                 if (alink->bytesInQueue < 0)
 2301                         alink->bytesInQueue = 0;
 2302                 else
 2303                         latency[activeLinkNum] +=
 2304                             (100 * alink->bytesInQueue) / alink->conf.bandwidth;
 2305         }
 2306 
 2307         /* Sort active links by latency */
 2308         qsort_r(sortByLatency,
 2309             priv->numActiveLinks, sizeof(*sortByLatency), latency, ng_ppp_intcmp);
 2310 
 2311         /* Find the interval we need (add links in sortByLatency[] order) */
 2312         for (numFragments = 1;
 2313             numFragments < priv->numActiveLinks; numFragments++) {
 2314                 for (total = i = 0; i < numFragments; i++) {
 2315                         int flowTime;
 2316 
 2317                         flowTime = latency[sortByLatency[numFragments]]
 2318                             - latency[sortByLatency[i]];
 2319                         total += ((flowTime * priv->links[
 2320                             priv->activeLinks[sortByLatency[i]]].conf.bandwidth)
 2321                                 + 99) / 100;
 2322                 }
 2323                 if (total >= len)
 2324                         break;
 2325         }
 2326 
 2327         /* Solve for t_0 in that interval */
 2328         for (topSum = botSum = i = 0; i < numFragments; i++) {
 2329                 int bw = priv->links[
 2330                     priv->activeLinks[sortByLatency[i]]].conf.bandwidth;
 2331 
 2332                 topSum += latency[sortByLatency[i]] * bw;       /* / 100 */
 2333                 botSum += bw;                                   /* / 100 */
 2334         }
 2335         t0 = ((len * 100) + topSum + botSum / 2) / botSum;
 2336 
 2337         /* Compute f_i(t_0) all i */
 2338         for (total = i = 0; i < numFragments; i++) {
 2339                 int bw = priv->links[
 2340                     priv->activeLinks[sortByLatency[i]]].conf.bandwidth;
 2341 
 2342                 distrib[sortByLatency[i]] =
 2343                     (bw * (t0 - latency[sortByLatency[i]]) + 50) / 100;
 2344                 total += distrib[sortByLatency[i]];
 2345         }
 2346 
 2347         /* Deal with any rounding error */
 2348         if (total < len) {
 2349                 struct ng_ppp_link *fastLink =
 2350                     &priv->links[priv->activeLinks[sortByLatency[0]]];
 2351                 int fast = 0;
 2352 
 2353                 /* Find the fastest link */
 2354                 for (i = 1; i < numFragments; i++) {
 2355                         struct ng_ppp_link *const link =
 2356                             &priv->links[priv->activeLinks[sortByLatency[i]]];
 2357 
 2358                         if (link->conf.bandwidth > fastLink->conf.bandwidth) {
 2359                                 fast = i;
 2360                                 fastLink = link;
 2361                         }
 2362                 }
 2363                 distrib[sortByLatency[fast]] += len - total;
 2364         } else while (total > len) {
 2365                 struct ng_ppp_link *slowLink =
 2366                     &priv->links[priv->activeLinks[sortByLatency[0]]];
 2367                 int delta, slow = 0;
 2368 
 2369                 /* Find the slowest link that still has bytes to remove */
 2370                 for (i = 1; i < numFragments; i++) {
 2371                         struct ng_ppp_link *const link =
 2372                             &priv->links[priv->activeLinks[sortByLatency[i]]];
 2373 
 2374                         if (distrib[sortByLatency[slow]] == 0
 2375                           || (distrib[sortByLatency[i]] > 0
 2376                             && link->conf.bandwidth <
 2377                               slowLink->conf.bandwidth)) {
 2378                                 slow = i;
 2379                                 slowLink = link;
 2380                         }
 2381                 }
 2382                 delta = total - len;
 2383                 if (delta > distrib[sortByLatency[slow]])
 2384                         delta = distrib[sortByLatency[slow]];
 2385                 distrib[sortByLatency[slow]] -= delta;
 2386                 total -= delta;
 2387         }
 2388 }
 2389 
 2390 /*
 2391  * Compare two integers
 2392  */
 2393 static int
 2394 ng_ppp_intcmp(void *latency, const void *v1, const void *v2)
 2395 {
 2396         const int index1 = *((const int *) v1);
 2397         const int index2 = *((const int *) v2);
 2398 
 2399         return ((int *)latency)[index1] - ((int *)latency)[index2];
 2400 }
 2401 
 2402 /*
 2403  * Prepend a possibly compressed PPP protocol number in front of a frame
 2404  */
 2405 static struct mbuf *
 2406 ng_ppp_addproto(struct mbuf *m, uint16_t proto, int compOK)
 2407 {
 2408         if (compOK && PROT_COMPRESSABLE(proto)) {
 2409                 uint8_t pbyte = (uint8_t)proto;
 2410 
 2411                 return ng_ppp_prepend(m, &pbyte, 1);
 2412         } else {
 2413                 uint16_t pword = htons((uint16_t)proto);
 2414 
 2415                 return ng_ppp_prepend(m, &pword, 2);
 2416         }
 2417 }
 2418 
 2419 /*
 2420  * Cut a possibly compressed PPP protocol number from the front of a frame.
 2421  */
 2422 static struct mbuf *
 2423 ng_ppp_cutproto(struct mbuf *m, uint16_t *proto)
 2424 {
 2425 
 2426         *proto = 0;
 2427         if (m->m_len < 1 && (m = m_pullup(m, 1)) == NULL)
 2428                 return (NULL);
 2429 
 2430         *proto = *mtod(m, uint8_t *);
 2431         m_adj(m, 1);
 2432 
 2433         if (!PROT_VALID(*proto)) {
 2434                 if (m->m_len < 1 && (m = m_pullup(m, 1)) == NULL)
 2435                         return (NULL);
 2436 
 2437                 *proto = (*proto << 8) + *mtod(m, uint8_t *);
 2438                 m_adj(m, 1);
 2439         }
 2440 
 2441         return (m);
 2442 }
 2443 
 2444 /*
 2445  * Prepend some bytes to an mbuf.
 2446  */
 2447 static struct mbuf *
 2448 ng_ppp_prepend(struct mbuf *m, const void *buf, int len)
 2449 {
 2450         M_PREPEND(m, len, M_DONTWAIT);
 2451         if (m == NULL || (m->m_len < len && (m = m_pullup(m, len)) == NULL))
 2452                 return (NULL);
 2453         bcopy(buf, mtod(m, uint8_t *), len);
 2454         return (m);
 2455 }
 2456 
 2457 /*
 2458  * Update private information that is derived from other private information
 2459  */
 2460 static void
 2461 ng_ppp_update(node_p node, int newConf)
 2462 {
 2463         const priv_p priv = NG_NODE_PRIVATE(node);
 2464         int i;
 2465 
 2466         /* Update active status for VJ Compression */
 2467         priv->vjCompHooked = priv->hooks[HOOK_INDEX_VJC_IP] != NULL
 2468             && priv->hooks[HOOK_INDEX_VJC_COMP] != NULL
 2469             && priv->hooks[HOOK_INDEX_VJC_UNCOMP] != NULL
 2470             && priv->hooks[HOOK_INDEX_VJC_VJIP] != NULL;
 2471 
 2472         /* Increase latency for each link an amount equal to one MP header */
 2473         if (newConf) {
 2474                 for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
 2475                         int hdrBytes;
 2476 
 2477                         if (priv->links[i].conf.bandwidth == 0)
 2478                             continue;
 2479                             
 2480                         hdrBytes = MP_AVERAGE_LINK_OVERHEAD
 2481                             + (priv->links[i].conf.enableACFComp ? 0 : 2)
 2482                             + (priv->links[i].conf.enableProtoComp ? 1 : 2)
 2483                             + (priv->conf.xmitShortSeq ? 2 : 4);
 2484                         priv->links[i].latency =
 2485                             priv->links[i].conf.latency +
 2486                             (hdrBytes / priv->links[i].conf.bandwidth + 50) / 100;
 2487                 }
 2488         }
 2489 
 2490         /* Update list of active links */
 2491         bzero(&priv->activeLinks, sizeof(priv->activeLinks));
 2492         priv->numActiveLinks = 0;
 2493         priv->allLinksEqual = 1;
 2494         for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
 2495                 struct ng_ppp_link *const link = &priv->links[i];
 2496 
 2497                 /* Is link active? */
 2498                 if (link->conf.enableLink && link->hook != NULL) {
 2499                         struct ng_ppp_link *link0;
 2500 
 2501                         /* Add link to list of active links */
 2502                         priv->activeLinks[priv->numActiveLinks++] = i;
 2503                         link0 = &priv->links[priv->activeLinks[0]];
 2504 
 2505                         /* Determine if all links are still equal */
 2506                         if (link->latency != link0->latency
 2507                           || link->conf.bandwidth != link0->conf.bandwidth)
 2508                                 priv->allLinksEqual = 0;
 2509 
 2510                         /* Initialize rec'd sequence number */
 2511                         if (link->seq == MP_NOSEQ) {
 2512                                 link->seq = (link == link0) ?
 2513                                     MP_INITIAL_SEQ : link0->seq;
 2514                         }
 2515                 } else
 2516                         link->seq = MP_NOSEQ;
 2517         }
 2518 
 2519         /* Update MP state as multi-link is active or not */
 2520         if (priv->conf.enableMultilink && priv->numActiveLinks > 0)
 2521                 ng_ppp_start_frag_timer(node);
 2522         else {
 2523                 ng_ppp_stop_frag_timer(node);
 2524                 ng_ppp_frag_reset(node);
 2525                 priv->xseq = MP_INITIAL_SEQ;
 2526                 priv->mseq = MP_INITIAL_SEQ;
 2527                 for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
 2528                         struct ng_ppp_link *const link = &priv->links[i];
 2529 
 2530                         bzero(&link->lastWrite, sizeof(link->lastWrite));
 2531                         link->bytesInQueue = 0;
 2532                         link->seq = MP_NOSEQ;
 2533                 }
 2534         }
 2535 }
 2536 
 2537 /*
 2538  * Determine if a new configuration would represent a valid change
 2539  * from the current configuration and link activity status.
 2540  */
 2541 static int
 2542 ng_ppp_config_valid(node_p node, const struct ng_ppp_node_conf *newConf)
 2543 {
 2544         const priv_p priv = NG_NODE_PRIVATE(node);
 2545         int i, newNumLinksActive;
 2546 
 2547         /* Check per-link config and count how many links would be active */
 2548         for (newNumLinksActive = i = 0; i < NG_PPP_MAX_LINKS; i++) {
 2549                 if (newConf->links[i].enableLink && priv->links[i].hook != NULL)
 2550                         newNumLinksActive++;
 2551                 if (!newConf->links[i].enableLink)
 2552                         continue;
 2553                 if (newConf->links[i].mru < MP_MIN_LINK_MRU)
 2554                         return (0);
 2555                 if (newConf->links[i].bandwidth == 0)
 2556                         return (0);
 2557                 if (newConf->links[i].bandwidth > NG_PPP_MAX_BANDWIDTH)
 2558                         return (0);
 2559                 if (newConf->links[i].latency > NG_PPP_MAX_LATENCY)
 2560                         return (0);
 2561         }
 2562 
 2563         /* Disallow changes to multi-link configuration while MP is active */
 2564         if (priv->numActiveLinks > 0 && newNumLinksActive > 0) {
 2565                 if (!priv->conf.enableMultilink
 2566                                 != !newConf->bund.enableMultilink
 2567                     || !priv->conf.xmitShortSeq != !newConf->bund.xmitShortSeq
 2568                     || !priv->conf.recvShortSeq != !newConf->bund.recvShortSeq)
 2569                         return (0);
 2570         }
 2571 
 2572         /* At most one link can be active unless multi-link is enabled */
 2573         if (!newConf->bund.enableMultilink && newNumLinksActive > 1)
 2574                 return (0);
 2575 
 2576         /* Configuration change would be valid */
 2577         return (1);
 2578 }
 2579 
 2580 /*
 2581  * Free all entries in the fragment queue
 2582  */
 2583 static void
 2584 ng_ppp_frag_reset(node_p node)
 2585 {
 2586         const priv_p priv = NG_NODE_PRIVATE(node);
 2587         struct ng_ppp_frag *qent, *qnext;
 2588 
 2589         for (qent = TAILQ_FIRST(&priv->frags); qent; qent = qnext) {
 2590                 qnext = TAILQ_NEXT(qent, f_qent);
 2591                 NG_FREE_M(qent->data);
 2592                 TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
 2593         }
 2594         TAILQ_INIT(&priv->frags);
 2595 }
 2596 
 2597 /*
 2598  * Start fragment queue timer
 2599  */
 2600 static void
 2601 ng_ppp_start_frag_timer(node_p node)
 2602 {
 2603         const priv_p priv = NG_NODE_PRIVATE(node);
 2604 
 2605         if (!(callout_pending(&priv->fragTimer)))
 2606                 ng_callout(&priv->fragTimer, node, NULL, MP_FRAGTIMER_INTERVAL,
 2607                     ng_ppp_frag_timeout, NULL, 0);
 2608 }
 2609 
 2610 /*
 2611  * Stop fragment queue timer
 2612  */
 2613 static void
 2614 ng_ppp_stop_frag_timer(node_p node)
 2615 {
 2616         const priv_p priv = NG_NODE_PRIVATE(node);
 2617 
 2618         if (callout_pending(&priv->fragTimer))
 2619                 ng_uncallout(&priv->fragTimer, node);
 2620 }

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