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

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    1 /*-
    2  * Copyright (c) 1996-2000 Whistle Communications, Inc.
    3  * All rights reserved.
    4  *
    5  * Subject to the following obligations and disclaimer of warranty, use and
    6  * redistribution of this software, in source or object code forms, with or
    7  * without modifications are expressly permitted by Whistle Communications;
    8  * provided, however, that:
    9  * 1. Any and all reproductions of the source or object code must include the
   10  *    copyright notice above and the following disclaimer of warranties; and
   11  * 2. No rights are granted, in any manner or form, to use Whistle
   12  *    Communications, Inc. trademarks, including the mark "WHISTLE
   13  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
   14  *    such appears in the above copyright notice or in the software.
   15  *
   16  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
   17  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
   18  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
   19  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
   20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
   21  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
   22  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
   23  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
   24  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
   25  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
   26  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
   27  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
   28  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
   29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   31  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
   32  * OF SUCH DAMAGE.
   33  *
   34  * Copyright (c) 2007 Alexander Motin <mav@alkar.net>
   35  * All rights reserved.
   36  *
   37  * Redistribution and use in source and binary forms, with or without
   38  * modification, are permitted provided that the following conditions
   39  * are met:
   40  * 1. Redistributions of source code must retain the above copyright
   41  *    notice unmodified, this list of conditions, and the following
   42  *    disclaimer.
   43  * 2. Redistributions in binary form must reproduce the above copyright
   44  *    notice, this list of conditions and the following disclaimer in the
   45  *    documentation and/or other materials provided with the distribution.
   46  *
   47  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   48  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   50  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   51  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   52  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   53  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   54  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   55  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   57  * SUCH DAMAGE.
   58  *
   59  * Authors: Archie Cobbs <archie@freebsd.org>, Alexander Motin <mav@alkar.net>
   60  *
   61  * $FreeBSD$
   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/errno.h>
  101 #include <sys/ctype.h>
  102 
  103 #include <netgraph/ng_message.h>
  104 #include <netgraph/netgraph.h>
  105 #include <netgraph/ng_parse.h>
  106 #include <netgraph/ng_ppp.h>
  107 #include <netgraph/ng_vjc.h>
  108 
  109 #ifdef NG_SEPARATE_MALLOC
  110 MALLOC_DEFINE(M_NETGRAPH_PPP, "netgraph_ppp", "netgraph ppp node");
  111 #else
  112 #define M_NETGRAPH_PPP M_NETGRAPH
  113 #endif
  114 
  115 #define PROT_VALID(p)           (((p) & 0x0101) == 0x0001)
  116 #define PROT_COMPRESSABLE(p)    (((p) & 0xff00) == 0x0000)
  117 
  118 /* Some PPP protocol numbers we're interested in */
  119 #define PROT_ATALK              0x0029
  120 #define PROT_COMPD              0x00fd
  121 #define PROT_CRYPTD             0x0053
  122 #define PROT_IP                 0x0021
  123 #define PROT_IPV6               0x0057
  124 #define PROT_IPX                0x002b
  125 #define PROT_LCP                0xc021
  126 #define PROT_MP                 0x003d
  127 #define PROT_VJCOMP             0x002d
  128 #define PROT_VJUNCOMP           0x002f
  129 
  130 /* Multilink PPP definitions */
  131 #define MP_MIN_MRRU             1500            /* per RFC 1990 */
  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         TAILQ_HEAD(ng_ppp_fraglist, ng_ppp_frag)        /* fragment queue */
  221                                 frags;
  222         int                     qlen;                   /* fraq queue length */
  223         struct callout          fragTimer;              /* fraq queue check */
  224         struct mtx              rmtx;                   /* recv mutex */
  225         struct mtx              xmtx;                   /* xmit mutex */
  226 };
  227 typedef struct ng_ppp_private *priv_p;
  228 
  229 /* Netgraph node methods */
  230 static ng_constructor_t ng_ppp_constructor;
  231 static ng_rcvmsg_t      ng_ppp_rcvmsg;
  232 static ng_shutdown_t    ng_ppp_shutdown;
  233 static ng_newhook_t     ng_ppp_newhook;
  234 static ng_rcvdata_t     ng_ppp_rcvdata;
  235 static ng_disconnect_t  ng_ppp_disconnect;
  236 
  237 static ng_rcvdata_t     ng_ppp_rcvdata_inet;
  238 static ng_rcvdata_t     ng_ppp_rcvdata_ipv6;
  239 static ng_rcvdata_t     ng_ppp_rcvdata_ipx;
  240 static ng_rcvdata_t     ng_ppp_rcvdata_atalk;
  241 static ng_rcvdata_t     ng_ppp_rcvdata_bypass;
  242 
  243 static ng_rcvdata_t     ng_ppp_rcvdata_vjc_ip;
  244 static ng_rcvdata_t     ng_ppp_rcvdata_vjc_comp;
  245 static ng_rcvdata_t     ng_ppp_rcvdata_vjc_uncomp;
  246 static ng_rcvdata_t     ng_ppp_rcvdata_vjc_vjip;
  247 
  248 static ng_rcvdata_t     ng_ppp_rcvdata_compress;
  249 static ng_rcvdata_t     ng_ppp_rcvdata_decompress;
  250 
  251 static ng_rcvdata_t     ng_ppp_rcvdata_encrypt;
  252 static ng_rcvdata_t     ng_ppp_rcvdata_decrypt;
  253 
  254 /* We use integer indicies to refer to the non-link hooks. */
  255 static const struct {
  256         char *const name;
  257         ng_rcvdata_t *fn;
  258 } ng_ppp_hook_names[] = {
  259 #define HOOK_INDEX_ATALK        0
  260         { NG_PPP_HOOK_ATALK,    ng_ppp_rcvdata_atalk },
  261 #define HOOK_INDEX_BYPASS       1
  262         { NG_PPP_HOOK_BYPASS,   ng_ppp_rcvdata_bypass },
  263 #define HOOK_INDEX_COMPRESS     2
  264         { NG_PPP_HOOK_COMPRESS, ng_ppp_rcvdata_compress },
  265 #define HOOK_INDEX_ENCRYPT      3
  266         { NG_PPP_HOOK_ENCRYPT,  ng_ppp_rcvdata_encrypt },
  267 #define HOOK_INDEX_DECOMPRESS   4
  268         { NG_PPP_HOOK_DECOMPRESS, ng_ppp_rcvdata_decompress },
  269 #define HOOK_INDEX_DECRYPT      5
  270         { NG_PPP_HOOK_DECRYPT,  ng_ppp_rcvdata_decrypt },
  271 #define HOOK_INDEX_INET         6
  272         { NG_PPP_HOOK_INET,     ng_ppp_rcvdata_inet },
  273 #define HOOK_INDEX_IPX          7
  274         { NG_PPP_HOOK_IPX,      ng_ppp_rcvdata_ipx },
  275 #define HOOK_INDEX_VJC_COMP     8
  276         { NG_PPP_HOOK_VJC_COMP, ng_ppp_rcvdata_vjc_comp },
  277 #define HOOK_INDEX_VJC_IP       9
  278         { NG_PPP_HOOK_VJC_IP,   ng_ppp_rcvdata_vjc_ip },
  279 #define HOOK_INDEX_VJC_UNCOMP   10
  280         { NG_PPP_HOOK_VJC_UNCOMP, ng_ppp_rcvdata_vjc_uncomp },
  281 #define HOOK_INDEX_VJC_VJIP     11
  282         { NG_PPP_HOOK_VJC_VJIP, ng_ppp_rcvdata_vjc_vjip },
  283 #define HOOK_INDEX_IPV6         12
  284         { NG_PPP_HOOK_IPV6,     ng_ppp_rcvdata_ipv6 },
  285         { NULL, NULL }
  286 };
  287 
  288 /* Helper functions */
  289 static int      ng_ppp_proto_recv(node_p node, item_p item, uint16_t proto,
  290                     uint16_t linkNum);
  291 static int      ng_ppp_hcomp_xmit(node_p node, item_p item, uint16_t proto);
  292 static int      ng_ppp_hcomp_recv(node_p node, item_p item, uint16_t proto,
  293                     uint16_t linkNum);
  294 static int      ng_ppp_comp_xmit(node_p node, item_p item, uint16_t proto);
  295 static int      ng_ppp_comp_recv(node_p node, item_p item, uint16_t proto,
  296                     uint16_t linkNum);
  297 static int      ng_ppp_crypt_xmit(node_p node, item_p item, uint16_t proto);
  298 static int      ng_ppp_crypt_recv(node_p node, item_p item, uint16_t proto,
  299                     uint16_t linkNum);
  300 static int      ng_ppp_mp_xmit(node_p node, item_p item, uint16_t proto);
  301 static int      ng_ppp_mp_recv(node_p node, item_p item, uint16_t proto,
  302                     uint16_t linkNum);
  303 static int      ng_ppp_link_xmit(node_p node, item_p item, uint16_t proto,
  304                     uint16_t linkNum, int plen);
  305 
  306 static int      ng_ppp_bypass(node_p node, item_p item, uint16_t proto,
  307                     uint16_t linkNum);
  308 
  309 static void     ng_ppp_bump_mseq(node_p node, int32_t new_mseq);
  310 static int      ng_ppp_frag_drop(node_p node);
  311 static int      ng_ppp_check_packet(node_p node);
  312 static void     ng_ppp_get_packet(node_p node, struct mbuf **mp);
  313 static int      ng_ppp_frag_process(node_p node);
  314 static int      ng_ppp_frag_trim(node_p node);
  315 static void     ng_ppp_frag_timeout(node_p node, hook_p hook, void *arg1,
  316                     int arg2);
  317 static void     ng_ppp_frag_checkstale(node_p node);
  318 static void     ng_ppp_frag_reset(node_p node);
  319 static void     ng_ppp_mp_strategy(node_p node, int len, int *distrib);
  320 static int      ng_ppp_intcmp(void *latency, const void *v1, const void *v2);
  321 static struct mbuf *ng_ppp_addproto(struct mbuf *m, uint16_t proto, int compOK);
  322 static struct mbuf *ng_ppp_cutproto(struct mbuf *m, uint16_t *proto);
  323 static struct mbuf *ng_ppp_prepend(struct mbuf *m, const void *buf, int len);
  324 static int      ng_ppp_config_valid(node_p node,
  325                     const struct ng_ppp_node_conf *newConf);
  326 static void     ng_ppp_update(node_p node, int newConf);
  327 static void     ng_ppp_start_frag_timer(node_p node);
  328 static void     ng_ppp_stop_frag_timer(node_p node);
  329 
  330 /* Parse type for struct ng_ppp_mp_state_type */
  331 static const struct ng_parse_fixedarray_info ng_ppp_rseq_array_info = {
  332         &ng_parse_hint32_type,
  333         NG_PPP_MAX_LINKS
  334 };
  335 static const struct ng_parse_type ng_ppp_rseq_array_type = {
  336         &ng_parse_fixedarray_type,
  337         &ng_ppp_rseq_array_info,
  338 };
  339 static const struct ng_parse_struct_field ng_ppp_mp_state_type_fields[]
  340         = NG_PPP_MP_STATE_TYPE_INFO(&ng_ppp_rseq_array_type);
  341 static const struct ng_parse_type ng_ppp_mp_state_type = {
  342         &ng_parse_struct_type,
  343         &ng_ppp_mp_state_type_fields
  344 };
  345 
  346 /* Parse type for struct ng_ppp_link_conf */
  347 static const struct ng_parse_struct_field ng_ppp_link_type_fields[]
  348         = NG_PPP_LINK_TYPE_INFO;
  349 static const struct ng_parse_type ng_ppp_link_type = {
  350         &ng_parse_struct_type,
  351         &ng_ppp_link_type_fields
  352 };
  353 
  354 /* Parse type for struct ng_ppp_bund_conf */
  355 static const struct ng_parse_struct_field ng_ppp_bund_type_fields[]
  356         = NG_PPP_BUND_TYPE_INFO;
  357 static const struct ng_parse_type ng_ppp_bund_type = {
  358         &ng_parse_struct_type,
  359         &ng_ppp_bund_type_fields
  360 };
  361 
  362 /* Parse type for struct ng_ppp_node_conf */
  363 static const struct ng_parse_fixedarray_info ng_ppp_array_info = {
  364         &ng_ppp_link_type,
  365         NG_PPP_MAX_LINKS
  366 };
  367 static const struct ng_parse_type ng_ppp_link_array_type = {
  368         &ng_parse_fixedarray_type,
  369         &ng_ppp_array_info,
  370 };
  371 static const struct ng_parse_struct_field ng_ppp_conf_type_fields[]
  372         = NG_PPP_CONFIG_TYPE_INFO(&ng_ppp_bund_type, &ng_ppp_link_array_type);
  373 static const struct ng_parse_type ng_ppp_conf_type = {
  374         &ng_parse_struct_type,
  375         &ng_ppp_conf_type_fields
  376 };
  377 
  378 /* Parse type for struct ng_ppp_link_stat */
  379 static const struct ng_parse_struct_field ng_ppp_stats_type_fields[]
  380         = NG_PPP_STATS_TYPE_INFO;
  381 static const struct ng_parse_type ng_ppp_stats_type = {
  382         &ng_parse_struct_type,
  383         &ng_ppp_stats_type_fields
  384 };
  385 
  386 /* Parse type for struct ng_ppp_link_stat64 */
  387 static const struct ng_parse_struct_field ng_ppp_stats64_type_fields[]
  388         = NG_PPP_STATS64_TYPE_INFO;
  389 static const struct ng_parse_type ng_ppp_stats64_type = {
  390         &ng_parse_struct_type,
  391         &ng_ppp_stats64_type_fields
  392 };
  393 
  394 /* List of commands and how to convert arguments to/from ASCII */
  395 static const struct ng_cmdlist ng_ppp_cmds[] = {
  396         {
  397           NGM_PPP_COOKIE,
  398           NGM_PPP_SET_CONFIG,
  399           "setconfig",
  400           &ng_ppp_conf_type,
  401           NULL
  402         },
  403         {
  404           NGM_PPP_COOKIE,
  405           NGM_PPP_GET_CONFIG,
  406           "getconfig",
  407           NULL,
  408           &ng_ppp_conf_type
  409         },
  410         {
  411           NGM_PPP_COOKIE,
  412           NGM_PPP_GET_MP_STATE,
  413           "getmpstate",
  414           NULL,
  415           &ng_ppp_mp_state_type
  416         },
  417         {
  418           NGM_PPP_COOKIE,
  419           NGM_PPP_GET_LINK_STATS,
  420           "getstats",
  421           &ng_parse_int16_type,
  422           &ng_ppp_stats_type
  423         },
  424         {
  425           NGM_PPP_COOKIE,
  426           NGM_PPP_CLR_LINK_STATS,
  427           "clrstats",
  428           &ng_parse_int16_type,
  429           NULL
  430         },
  431         {
  432           NGM_PPP_COOKIE,
  433           NGM_PPP_GETCLR_LINK_STATS,
  434           "getclrstats",
  435           &ng_parse_int16_type,
  436           &ng_ppp_stats_type
  437         },
  438         {
  439           NGM_PPP_COOKIE,
  440           NGM_PPP_GET_LINK_STATS64,
  441           "getstats64",
  442           &ng_parse_int16_type,
  443           &ng_ppp_stats64_type
  444         },
  445         {
  446           NGM_PPP_COOKIE,
  447           NGM_PPP_GETCLR_LINK_STATS64,
  448           "getclrstats64",
  449           &ng_parse_int16_type,
  450           &ng_ppp_stats64_type
  451         },
  452         { 0 }
  453 };
  454 
  455 /* Node type descriptor */
  456 static struct ng_type ng_ppp_typestruct = {
  457         .version =      NG_ABI_VERSION,
  458         .name =         NG_PPP_NODE_TYPE,
  459         .constructor =  ng_ppp_constructor,
  460         .rcvmsg =       ng_ppp_rcvmsg,
  461         .shutdown =     ng_ppp_shutdown,
  462         .newhook =      ng_ppp_newhook,
  463         .rcvdata =      ng_ppp_rcvdata,
  464         .disconnect =   ng_ppp_disconnect,
  465         .cmdlist =      ng_ppp_cmds,
  466 };
  467 NETGRAPH_INIT(ppp, &ng_ppp_typestruct);
  468 
  469 /* Address and control field header */
  470 static const uint8_t ng_ppp_acf[2] = { 0xff, 0x03 };
  471 
  472 /* Maximum time we'll let a complete incoming packet sit in the queue */
  473 static const struct timeval ng_ppp_max_staleness = { 2, 0 };    /* 2 seconds */
  474 
  475 #define ERROUT(x)       do { error = (x); goto done; } while (0)
  476 
  477 /************************************************************************
  478                         NETGRAPH NODE STUFF
  479  ************************************************************************/
  480 
  481 /*
  482  * Node type constructor
  483  */
  484 static int
  485 ng_ppp_constructor(node_p node)
  486 {
  487         priv_p priv;
  488         int i;
  489 
  490         /* Allocate private structure */
  491         MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_PPP, M_NOWAIT | M_ZERO);
  492         if (priv == NULL)
  493                 return (ENOMEM);
  494 
  495         NG_NODE_SET_PRIVATE(node, priv);
  496 
  497         /* Initialize state */
  498         TAILQ_INIT(&priv->frags);
  499         for (i = 0; i < NG_PPP_MAX_LINKS; i++)
  500                 priv->links[i].seq = MP_NOSEQ;
  501         ng_callout_init(&priv->fragTimer);
  502 
  503         mtx_init(&priv->rmtx, "ng_ppp_recv", NULL, MTX_DEF);
  504         mtx_init(&priv->xmtx, "ng_ppp_xmit", NULL, MTX_DEF);
  505 
  506         /* Done */
  507         return (0);
  508 }
  509 
  510 /*
  511  * Give our OK for a hook to be added
  512  */
  513 static int
  514 ng_ppp_newhook(node_p node, hook_p hook, const char *name)
  515 {
  516         const priv_p priv = NG_NODE_PRIVATE(node);
  517         hook_p *hookPtr = NULL;
  518         int linkNum = -1;
  519         int hookIndex = -1;
  520 
  521         /* Figure out which hook it is */
  522         if (strncmp(name, NG_PPP_HOOK_LINK_PREFIX,      /* a link hook? */
  523             strlen(NG_PPP_HOOK_LINK_PREFIX)) == 0) {
  524                 const char *cp;
  525                 char *eptr;
  526 
  527                 cp = name + strlen(NG_PPP_HOOK_LINK_PREFIX);
  528                 if (!isdigit(*cp) || (cp[0] == '' && cp[1] != '\0'))
  529                         return (EINVAL);
  530                 linkNum = (int)strtoul(cp, &eptr, 10);
  531                 if (*eptr != '\0' || linkNum < 0 || linkNum >= NG_PPP_MAX_LINKS)
  532                         return (EINVAL);
  533                 hookPtr = &priv->links[linkNum].hook;
  534                 hookIndex = ~linkNum;
  535 
  536                 /* See if hook is already connected. */
  537                 if (*hookPtr != NULL)
  538                         return (EISCONN);
  539 
  540                 /* Disallow more than one link unless multilink is enabled. */
  541                 if (priv->links[linkNum].conf.enableLink &&
  542                     !priv->conf.enableMultilink && priv->numActiveLinks >= 1)
  543                         return (ENODEV);
  544 
  545         } else {                                /* must be a non-link hook */
  546                 int i;
  547 
  548                 for (i = 0; ng_ppp_hook_names[i].name != NULL; i++) {
  549                         if (strcmp(name, ng_ppp_hook_names[i].name) == 0) {
  550                                 hookPtr = &priv->hooks[i];
  551                                 hookIndex = i;
  552                                 break;
  553                         }
  554                 }
  555                 if (ng_ppp_hook_names[i].name == NULL)
  556                         return (EINVAL);        /* no such hook */
  557 
  558                 /* See if hook is already connected */
  559                 if (*hookPtr != NULL)
  560                         return (EISCONN);
  561 
  562                 /* Every non-linkX hook have it's own function. */
  563                 NG_HOOK_SET_RCVDATA(hook, ng_ppp_hook_names[i].fn);
  564         }
  565 
  566         /* OK */
  567         *hookPtr = hook;
  568         NG_HOOK_SET_PRIVATE(hook, (void *)(intptr_t)hookIndex);
  569         ng_ppp_update(node, 0);
  570         return (0);
  571 }
  572 
  573 /*
  574  * Receive a control message
  575  */
  576 static int
  577 ng_ppp_rcvmsg(node_p node, item_p item, hook_p lasthook)
  578 {
  579         const priv_p priv = NG_NODE_PRIVATE(node);
  580         struct ng_mesg *resp = NULL;
  581         int error = 0;
  582         struct ng_mesg *msg;
  583 
  584         NGI_GET_MSG(item, msg);
  585         switch (msg->header.typecookie) {
  586         case NGM_PPP_COOKIE:
  587                 switch (msg->header.cmd) {
  588                 case NGM_PPP_SET_CONFIG:
  589                     {
  590                         struct ng_ppp_node_conf *const conf =
  591                             (struct ng_ppp_node_conf *)msg->data;
  592                         int i;
  593 
  594                         /* Check for invalid or illegal config */
  595                         if (msg->header.arglen != sizeof(*conf))
  596                                 ERROUT(EINVAL);
  597                         if (!ng_ppp_config_valid(node, conf))
  598                                 ERROUT(EINVAL);
  599 
  600                         /* Copy config */
  601                         priv->conf = conf->bund;
  602                         for (i = 0; i < NG_PPP_MAX_LINKS; i++)
  603                                 priv->links[i].conf = conf->links[i];
  604                         ng_ppp_update(node, 1);
  605                         break;
  606                     }
  607                 case NGM_PPP_GET_CONFIG:
  608                     {
  609                         struct ng_ppp_node_conf *conf;
  610                         int i;
  611 
  612                         NG_MKRESPONSE(resp, msg, sizeof(*conf), M_NOWAIT);
  613                         if (resp == NULL)
  614                                 ERROUT(ENOMEM);
  615                         conf = (struct ng_ppp_node_conf *)resp->data;
  616                         conf->bund = priv->conf;
  617                         for (i = 0; i < NG_PPP_MAX_LINKS; i++)
  618                                 conf->links[i] = priv->links[i].conf;
  619                         break;
  620                     }
  621                 case NGM_PPP_GET_MP_STATE:
  622                     {
  623                         struct ng_ppp_mp_state *info;
  624                         int i;
  625 
  626                         NG_MKRESPONSE(resp, msg, sizeof(*info), M_NOWAIT);
  627                         if (resp == NULL)
  628                                 ERROUT(ENOMEM);
  629                         info = (struct ng_ppp_mp_state *)resp->data;
  630                         bzero(info, sizeof(*info));
  631                         for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
  632                                 if (priv->links[i].seq != MP_NOSEQ)
  633                                         info->rseq[i] = priv->links[i].seq;
  634                         }
  635                         info->mseq = priv->mseq;
  636                         info->xseq = priv->xseq;
  637                         break;
  638                     }
  639                 case NGM_PPP_GET_LINK_STATS:
  640                 case NGM_PPP_CLR_LINK_STATS:
  641                 case NGM_PPP_GETCLR_LINK_STATS:
  642                 case NGM_PPP_GET_LINK_STATS64:
  643                 case NGM_PPP_GETCLR_LINK_STATS64:
  644                     {
  645                         struct ng_ppp_link_stat64 *stats;
  646                         uint16_t linkNum;
  647 
  648                         /* Process request. */
  649                         if (msg->header.arglen != sizeof(uint16_t))
  650                                 ERROUT(EINVAL);
  651                         linkNum = *((uint16_t *) msg->data);
  652                         if (linkNum >= NG_PPP_MAX_LINKS
  653                             && linkNum != NG_PPP_BUNDLE_LINKNUM)
  654                                 ERROUT(EINVAL);
  655                         stats = (linkNum == NG_PPP_BUNDLE_LINKNUM) ?
  656                             &priv->bundleStats : &priv->links[linkNum].stats;
  657 
  658                         /* Make 64bit reply. */
  659                         if (msg->header.cmd == NGM_PPP_GET_LINK_STATS64 || 
  660                             msg->header.cmd == NGM_PPP_GETCLR_LINK_STATS64) {
  661                                 NG_MKRESPONSE(resp, msg,
  662                                     sizeof(struct ng_ppp_link_stat64), M_NOWAIT);
  663                                 if (resp == NULL)
  664                                         ERROUT(ENOMEM);
  665                                 bcopy(stats, resp->data, sizeof(*stats));
  666                         } else
  667                         /* Make 32bit reply. */
  668                         if (msg->header.cmd == NGM_PPP_GET_LINK_STATS || 
  669                             msg->header.cmd == NGM_PPP_GETCLR_LINK_STATS) {
  670                                 struct ng_ppp_link_stat *rs;
  671                                 NG_MKRESPONSE(resp, msg,
  672                                     sizeof(struct ng_ppp_link_stat), M_NOWAIT);
  673                                 if (resp == NULL)
  674                                         ERROUT(ENOMEM);
  675                                 rs = (struct ng_ppp_link_stat *)resp->data;
  676                                 /* Truncate 64->32 bits. */
  677                                 rs->xmitFrames = stats->xmitFrames;
  678                                 rs->xmitOctets = stats->xmitOctets;
  679                                 rs->recvFrames = stats->recvFrames;
  680                                 rs->recvOctets = stats->recvOctets;
  681                                 rs->badProtos = stats->badProtos;
  682                                 rs->runts = stats->runts;
  683                                 rs->dupFragments = stats->dupFragments;
  684                                 rs->dropFragments = stats->dropFragments;
  685                         }
  686                         /* Clear stats. */
  687                         if (msg->header.cmd != NGM_PPP_GET_LINK_STATS &&
  688                             msg->header.cmd != NGM_PPP_GET_LINK_STATS64)
  689                                 bzero(stats, sizeof(*stats));
  690                         break;
  691                     }
  692                 default:
  693                         error = EINVAL;
  694                         break;
  695                 }
  696                 break;
  697         case NGM_VJC_COOKIE:
  698             {
  699                 /*
  700                  * Forward it to the vjc node. leave the
  701                  * old return address alone.
  702                  * If we have no hook, let NG_RESPOND_MSG
  703                  * clean up any remaining resources.
  704                  * Because we have no resp, the item will be freed
  705                  * along with anything it references. Don't
  706                  * let msg be freed twice.
  707                  */
  708                 NGI_MSG(item) = msg;    /* put it back in the item */
  709                 msg = NULL;
  710                 if ((lasthook = priv->hooks[HOOK_INDEX_VJC_IP])) {
  711                         NG_FWD_ITEM_HOOK(error, item, lasthook);
  712                 }
  713                 return (error);
  714             }
  715         default:
  716                 error = EINVAL;
  717                 break;
  718         }
  719 done:
  720         NG_RESPOND_MSG(error, node, item, resp);
  721         NG_FREE_MSG(msg);
  722         return (error);
  723 }
  724 
  725 /*
  726  * Destroy node
  727  */
  728 static int
  729 ng_ppp_shutdown(node_p node)
  730 {
  731         const priv_p priv = NG_NODE_PRIVATE(node);
  732 
  733         /* Stop fragment queue timer */
  734         ng_ppp_stop_frag_timer(node);
  735 
  736         /* Take down netgraph node */
  737         ng_ppp_frag_reset(node);
  738         mtx_destroy(&priv->rmtx);
  739         mtx_destroy(&priv->xmtx);
  740         bzero(priv, sizeof(*priv));
  741         FREE(priv, M_NETGRAPH_PPP);
  742         NG_NODE_SET_PRIVATE(node, NULL);
  743         NG_NODE_UNREF(node);            /* let the node escape */
  744         return (0);
  745 }
  746 
  747 /*
  748  * Hook disconnection
  749  */
  750 static int
  751 ng_ppp_disconnect(hook_p hook)
  752 {
  753         const node_p node = NG_HOOK_NODE(hook);
  754         const priv_p priv = NG_NODE_PRIVATE(node);
  755         const int index = (intptr_t)NG_HOOK_PRIVATE(hook);
  756 
  757         /* Zero out hook pointer */
  758         if (index < 0)
  759                 priv->links[~index].hook = NULL;
  760         else
  761                 priv->hooks[index] = NULL;
  762 
  763         /* Update derived info (or go away if no hooks left). */
  764         if (NG_NODE_NUMHOOKS(node) > 0)
  765                 ng_ppp_update(node, 0);
  766         else if (NG_NODE_IS_VALID(node))
  767                 ng_rmnode_self(node);
  768 
  769         return (0);
  770 }
  771 
  772 /*
  773  * Proto layer
  774  */
  775 
  776 /*
  777  * Receive data on a hook inet.
  778  */
  779 static int
  780 ng_ppp_rcvdata_inet(hook_p hook, item_p item)
  781 {
  782         const node_p node = NG_HOOK_NODE(hook);
  783         const priv_p priv = NG_NODE_PRIVATE(node);
  784 
  785         if (!priv->conf.enableIP) {
  786                 NG_FREE_ITEM(item);
  787                 return (ENXIO);
  788         }
  789         return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_IP));
  790 }
  791 
  792 /*
  793  * Receive data on a hook ipv6.
  794  */
  795 static int
  796 ng_ppp_rcvdata_ipv6(hook_p hook, item_p item)
  797 {
  798         const node_p node = NG_HOOK_NODE(hook);
  799         const priv_p priv = NG_NODE_PRIVATE(node);
  800 
  801         if (!priv->conf.enableIPv6) {
  802                 NG_FREE_ITEM(item);
  803                 return (ENXIO);
  804         }
  805         return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_IPV6));
  806 }
  807 
  808 /*
  809  * Receive data on a hook atalk.
  810  */
  811 static int
  812 ng_ppp_rcvdata_atalk(hook_p hook, item_p item)
  813 {
  814         const node_p node = NG_HOOK_NODE(hook);
  815         const priv_p priv = NG_NODE_PRIVATE(node);
  816 
  817         if (!priv->conf.enableAtalk) {
  818                 NG_FREE_ITEM(item);
  819                 return (ENXIO);
  820         }
  821         return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_ATALK));
  822 }
  823 
  824 /*
  825  * Receive data on a hook ipx
  826  */
  827 static int
  828 ng_ppp_rcvdata_ipx(hook_p hook, item_p item)
  829 {
  830         const node_p node = NG_HOOK_NODE(hook);
  831         const priv_p priv = NG_NODE_PRIVATE(node);
  832 
  833         if (!priv->conf.enableIPX) {
  834                 NG_FREE_ITEM(item);
  835                 return (ENXIO);
  836         }
  837         return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_IPX));
  838 }
  839 
  840 /*
  841  * Receive data on a hook bypass
  842  */
  843 static int
  844 ng_ppp_rcvdata_bypass(hook_p hook, item_p item)
  845 {
  846         uint16_t linkNum;
  847         uint16_t proto;
  848         struct mbuf *m;
  849 
  850         NGI_GET_M(item, m);
  851         if (m->m_pkthdr.len < 4) {
  852                 NG_FREE_ITEM(item);
  853                 return (EINVAL);
  854         }
  855         if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
  856                 NG_FREE_ITEM(item);
  857                 return (ENOBUFS);
  858         }
  859         linkNum = ntohs(mtod(m, uint16_t *)[0]);
  860         proto = ntohs(mtod(m, uint16_t *)[1]);
  861         m_adj(m, 4);
  862         NGI_M(item) = m;
  863 
  864         if (linkNum == NG_PPP_BUNDLE_LINKNUM)
  865                 return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, proto));
  866         else
  867                 return (ng_ppp_link_xmit(NG_HOOK_NODE(hook), item, proto,
  868                     linkNum, 0));
  869 }
  870 
  871 static int
  872 ng_ppp_bypass(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
  873 {
  874         const priv_p priv = NG_NODE_PRIVATE(node);
  875         uint16_t hdr[2];
  876         struct mbuf *m;
  877         int error;
  878 
  879         if (priv->hooks[HOOK_INDEX_BYPASS] == NULL) {
  880             NG_FREE_ITEM(item);
  881             return (ENXIO);
  882         }
  883 
  884         /* Add 4-byte bypass header. */
  885         hdr[0] = htons(linkNum);
  886         hdr[1] = htons(proto);
  887 
  888         NGI_GET_M(item, m);
  889         if ((m = ng_ppp_prepend(m, &hdr, 4)) == NULL) {
  890                 NG_FREE_ITEM(item);
  891                 return (ENOBUFS);
  892         }
  893         NGI_M(item) = m;
  894 
  895         /* Send packet out hook. */
  896         NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_BYPASS]);
  897         return (error);
  898 }
  899 
  900 static int
  901 ng_ppp_proto_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
  902 {
  903         const priv_p priv = NG_NODE_PRIVATE(node);
  904         hook_p outHook = NULL;
  905         int error;
  906 
  907         switch (proto) {
  908             case PROT_IP:
  909                 if (priv->conf.enableIP)
  910                     outHook = priv->hooks[HOOK_INDEX_INET];
  911                 break;
  912             case PROT_IPV6:
  913                 if (priv->conf.enableIPv6)
  914                     outHook = priv->hooks[HOOK_INDEX_IPV6];
  915                 break;
  916             case PROT_ATALK:
  917                 if (priv->conf.enableAtalk)
  918                     outHook = priv->hooks[HOOK_INDEX_ATALK];
  919                 break;
  920             case PROT_IPX:
  921                 if (priv->conf.enableIPX)
  922                     outHook = priv->hooks[HOOK_INDEX_IPX];
  923                 break;
  924         }
  925 
  926         if (outHook == NULL)
  927                 return (ng_ppp_bypass(node, item, proto, linkNum));
  928 
  929         /* Send packet out hook. */
  930         NG_FWD_ITEM_HOOK(error, item, outHook);
  931         return (error);
  932 }
  933 
  934 /*
  935  * Header compression layer
  936  */
  937 
  938 static int
  939 ng_ppp_hcomp_xmit(node_p node, item_p item, uint16_t proto)
  940 {
  941         const priv_p priv = NG_NODE_PRIVATE(node);
  942 
  943         if (proto == PROT_IP &&
  944             priv->conf.enableVJCompression &&
  945             priv->vjCompHooked) {
  946                 int error;
  947 
  948                 /* Send packet out hook. */
  949                 NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_VJC_IP]);
  950                 return (error);
  951         }
  952 
  953         return (ng_ppp_comp_xmit(node, item, proto));
  954 }
  955 
  956 /*
  957  * Receive data on a hook vjc_comp.
  958  */
  959 static int
  960 ng_ppp_rcvdata_vjc_comp(hook_p hook, item_p item)
  961 {
  962         const node_p node = NG_HOOK_NODE(hook);
  963         const priv_p priv = NG_NODE_PRIVATE(node);
  964 
  965         if (!priv->conf.enableVJCompression) {
  966                 NG_FREE_ITEM(item);
  967                 return (ENXIO);
  968         }
  969         return (ng_ppp_comp_xmit(node, item, PROT_VJCOMP));
  970 }
  971 
  972 /*
  973  * Receive data on a hook vjc_uncomp.
  974  */
  975 static int
  976 ng_ppp_rcvdata_vjc_uncomp(hook_p hook, item_p item)
  977 {
  978         const node_p node = NG_HOOK_NODE(hook);
  979         const priv_p priv = NG_NODE_PRIVATE(node);
  980 
  981         if (!priv->conf.enableVJCompression) {
  982                 NG_FREE_ITEM(item);
  983                 return (ENXIO);
  984         }
  985         return (ng_ppp_comp_xmit(node, item, PROT_VJUNCOMP));
  986 }
  987 
  988 /*
  989  * Receive data on a hook vjc_vjip.
  990  */
  991 static int
  992 ng_ppp_rcvdata_vjc_vjip(hook_p hook, item_p item)
  993 {
  994         const node_p node = NG_HOOK_NODE(hook);
  995         const priv_p priv = NG_NODE_PRIVATE(node);
  996 
  997         if (!priv->conf.enableVJCompression) {
  998                 NG_FREE_ITEM(item);
  999                 return (ENXIO);
 1000         }
 1001         return (ng_ppp_comp_xmit(node, item, PROT_IP));
 1002 }
 1003 
 1004 static int
 1005 ng_ppp_hcomp_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
 1006 {
 1007         const priv_p priv = NG_NODE_PRIVATE(node);
 1008 
 1009         if (priv->conf.enableVJDecompression && priv->vjCompHooked) {
 1010                 hook_p outHook = NULL;
 1011 
 1012                 switch (proto) {
 1013                     case PROT_VJCOMP:
 1014                         outHook = priv->hooks[HOOK_INDEX_VJC_COMP];
 1015                         break;
 1016                     case PROT_VJUNCOMP:
 1017                         outHook = priv->hooks[HOOK_INDEX_VJC_UNCOMP];
 1018                         break;
 1019                 }
 1020 
 1021                 if (outHook) {
 1022                         int error;
 1023 
 1024                         /* Send packet out hook. */
 1025                         NG_FWD_ITEM_HOOK(error, item, outHook);
 1026                         return (error);
 1027                 }
 1028         }
 1029 
 1030         return (ng_ppp_proto_recv(node, item, proto, linkNum));
 1031 }
 1032 
 1033 /*
 1034  * Receive data on a hook vjc_ip.
 1035  */
 1036 static int
 1037 ng_ppp_rcvdata_vjc_ip(hook_p hook, item_p item)
 1038 {
 1039         const node_p node = NG_HOOK_NODE(hook);
 1040         const priv_p priv = NG_NODE_PRIVATE(node);
 1041 
 1042         if (!priv->conf.enableVJDecompression) {
 1043                 NG_FREE_ITEM(item);
 1044                 return (ENXIO);
 1045         }
 1046         return (ng_ppp_proto_recv(node, item, PROT_IP, NG_PPP_BUNDLE_LINKNUM));
 1047 }
 1048 
 1049 /*
 1050  * Compression layer
 1051  */
 1052 
 1053 static int
 1054 ng_ppp_comp_xmit(node_p node, item_p item, uint16_t proto)
 1055 {
 1056         const priv_p priv = NG_NODE_PRIVATE(node);
 1057 
 1058         if (priv->conf.enableCompression &&
 1059             proto < 0x4000 &&
 1060             proto != PROT_COMPD &&
 1061             proto != PROT_CRYPTD &&
 1062             priv->hooks[HOOK_INDEX_COMPRESS] != NULL) {
 1063                 struct mbuf *m;
 1064                 int error;
 1065 
 1066                 NGI_GET_M(item, m);
 1067                 if ((m = ng_ppp_addproto(m, proto, 0)) == NULL) {
 1068                         NG_FREE_ITEM(item);
 1069                         return (ENOBUFS);
 1070                 }
 1071                 NGI_M(item) = m;
 1072 
 1073                 /* Send packet out hook. */
 1074                 NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_COMPRESS]);
 1075                 return (error);
 1076         }
 1077 
 1078         return (ng_ppp_crypt_xmit(node, item, proto));
 1079 }
 1080 
 1081 /*
 1082  * Receive data on a hook compress.
 1083  */
 1084 static int
 1085 ng_ppp_rcvdata_compress(hook_p hook, item_p item)
 1086 {
 1087         const node_p node = NG_HOOK_NODE(hook);
 1088         const priv_p priv = NG_NODE_PRIVATE(node);
 1089         uint16_t proto;
 1090 
 1091         switch (priv->conf.enableCompression) {
 1092             case NG_PPP_COMPRESS_NONE:
 1093                 NG_FREE_ITEM(item);
 1094                 return (ENXIO);
 1095             case NG_PPP_COMPRESS_FULL:
 1096                 {
 1097                         struct mbuf *m;
 1098 
 1099                         NGI_GET_M(item, m);
 1100                         if ((m = ng_ppp_cutproto(m, &proto)) == NULL) {
 1101                                 NG_FREE_ITEM(item);
 1102                                 return (EIO);
 1103                         }
 1104                         NGI_M(item) = m;
 1105                         if (!PROT_VALID(proto)) {
 1106                                 NG_FREE_ITEM(item);
 1107                                 return (EIO);
 1108                         }
 1109                 }
 1110                 break;
 1111             default:
 1112                 proto = PROT_COMPD;
 1113                 break;
 1114         }
 1115         return (ng_ppp_crypt_xmit(node, item, proto));
 1116 }
 1117 
 1118 static int
 1119 ng_ppp_comp_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
 1120 {
 1121         const priv_p priv = NG_NODE_PRIVATE(node);
 1122 
 1123         if (proto < 0x4000 &&
 1124             ((proto == PROT_COMPD && priv->conf.enableDecompression) ||
 1125             priv->conf.enableDecompression == NG_PPP_DECOMPRESS_FULL) &&
 1126             priv->hooks[HOOK_INDEX_DECOMPRESS] != NULL) {
 1127                 int error;
 1128 
 1129                 if (priv->conf.enableDecompression == NG_PPP_DECOMPRESS_FULL) {
 1130                         struct mbuf *m;
 1131                         NGI_GET_M(item, m);
 1132                         if ((m = ng_ppp_addproto(m, proto, 0)) == NULL) {
 1133                                 NG_FREE_ITEM(item);
 1134                                 return (EIO);
 1135                         }
 1136                         NGI_M(item) = m;
 1137                 }
 1138 
 1139                 /* Send packet out hook. */
 1140                 NG_FWD_ITEM_HOOK(error, item,
 1141                     priv->hooks[HOOK_INDEX_DECOMPRESS]);
 1142                 return (error);
 1143         } else if (proto == PROT_COMPD) {
 1144                 /* Disabled protos MUST be silently discarded, but
 1145                  * unsupported MUST not. Let user-level decide this. */
 1146                 return (ng_ppp_bypass(node, item, proto, linkNum));
 1147         }
 1148 
 1149         return (ng_ppp_hcomp_recv(node, item, proto, linkNum));
 1150 }
 1151 
 1152 /*
 1153  * Receive data on a hook decompress.
 1154  */
 1155 static int
 1156 ng_ppp_rcvdata_decompress(hook_p hook, item_p item)
 1157 {
 1158         const node_p node = NG_HOOK_NODE(hook);
 1159         const priv_p priv = NG_NODE_PRIVATE(node);
 1160         uint16_t proto;
 1161         struct mbuf *m;
 1162 
 1163         if (!priv->conf.enableDecompression) {
 1164                 NG_FREE_ITEM(item);
 1165                 return (ENXIO);
 1166         }
 1167         NGI_GET_M(item, m);
 1168         if ((m = ng_ppp_cutproto(m, &proto)) == NULL) {
 1169                 NG_FREE_ITEM(item);
 1170                 return (EIO);
 1171         }
 1172         NGI_M(item) = m;
 1173         if (!PROT_VALID(proto)) {
 1174                 priv->bundleStats.badProtos++;
 1175                 NG_FREE_ITEM(item);
 1176                 return (EIO);
 1177         }
 1178         return (ng_ppp_hcomp_recv(node, item, proto, NG_PPP_BUNDLE_LINKNUM));
 1179 }
 1180 
 1181 /*
 1182  * Encryption layer
 1183  */
 1184 
 1185 static int
 1186 ng_ppp_crypt_xmit(node_p node, item_p item, uint16_t proto)
 1187 {
 1188         const priv_p priv = NG_NODE_PRIVATE(node);
 1189 
 1190         if (priv->conf.enableEncryption &&
 1191             proto < 0x4000 &&
 1192             proto != PROT_CRYPTD &&
 1193             priv->hooks[HOOK_INDEX_ENCRYPT] != NULL) {
 1194                 struct mbuf *m;
 1195                 int error;
 1196 
 1197                 NGI_GET_M(item, m);
 1198                 if ((m = ng_ppp_addproto(m, proto, 0)) == NULL) {
 1199                         NG_FREE_ITEM(item);
 1200                         return (ENOBUFS);
 1201                 }
 1202                 NGI_M(item) = m;
 1203 
 1204                 /* Send packet out hook. */
 1205                 NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_ENCRYPT]);
 1206                 return (error);
 1207         }
 1208 
 1209         return (ng_ppp_mp_xmit(node, item, proto));
 1210 }
 1211 
 1212 /*
 1213  * Receive data on a hook encrypt.
 1214  */
 1215 static int
 1216 ng_ppp_rcvdata_encrypt(hook_p hook, item_p item)
 1217 {
 1218         const node_p node = NG_HOOK_NODE(hook);
 1219         const priv_p priv = NG_NODE_PRIVATE(node);
 1220 
 1221         if (!priv->conf.enableEncryption) {
 1222                 NG_FREE_ITEM(item);
 1223                 return (ENXIO);
 1224         }
 1225         return (ng_ppp_mp_xmit(node, item, PROT_CRYPTD));
 1226 }
 1227 
 1228 static int
 1229 ng_ppp_crypt_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
 1230 {
 1231         const priv_p priv = NG_NODE_PRIVATE(node);
 1232 
 1233         if (proto == PROT_CRYPTD) {
 1234                 if (priv->conf.enableDecryption &&
 1235                     priv->hooks[HOOK_INDEX_DECRYPT] != NULL) {
 1236                         int error;
 1237 
 1238                         /* Send packet out hook. */
 1239                         NG_FWD_ITEM_HOOK(error, item,
 1240                             priv->hooks[HOOK_INDEX_DECRYPT]);
 1241                         return (error);
 1242                 } else {
 1243                         /* Disabled protos MUST be silently discarded, but
 1244                          * unsupported MUST not. Let user-level decide this. */
 1245                         return (ng_ppp_bypass(node, item, proto, linkNum));
 1246                 }
 1247         }
 1248 
 1249         return (ng_ppp_comp_recv(node, item, proto, linkNum));
 1250 }
 1251 
 1252 /*
 1253  * Receive data on a hook decrypt.
 1254  */
 1255 static int
 1256 ng_ppp_rcvdata_decrypt(hook_p hook, item_p item)
 1257 {
 1258         const node_p node = NG_HOOK_NODE(hook);
 1259         const priv_p priv = NG_NODE_PRIVATE(node);
 1260         uint16_t proto;
 1261         struct mbuf *m;
 1262 
 1263         if (!priv->conf.enableDecryption) {
 1264                 NG_FREE_ITEM(item);
 1265                 return (ENXIO);
 1266         }
 1267         NGI_GET_M(item, m);
 1268         if ((m = ng_ppp_cutproto(m, &proto)) == NULL) {
 1269                 NG_FREE_ITEM(item);
 1270                 return (EIO);
 1271         }
 1272         NGI_M(item) = m;
 1273         if (!PROT_VALID(proto)) {
 1274                 priv->bundleStats.badProtos++;
 1275                 NG_FREE_ITEM(item);
 1276                 return (EIO);
 1277         }
 1278         return (ng_ppp_comp_recv(node, item, proto, NG_PPP_BUNDLE_LINKNUM));
 1279 }
 1280 
 1281 /*
 1282  * Link layer
 1283  */
 1284 
 1285 static int
 1286 ng_ppp_link_xmit(node_p node, item_p item, uint16_t proto, uint16_t linkNum, int plen)
 1287 {
 1288         const priv_p priv = NG_NODE_PRIVATE(node);
 1289         struct ng_ppp_link *link;
 1290         int len, error;
 1291         struct mbuf *m;
 1292         uint16_t mru;
 1293 
 1294         /* Check if link correct. */
 1295         if (linkNum >= NG_PPP_MAX_LINKS) {
 1296                 ERROUT(ENETDOWN);
 1297         }
 1298 
 1299         /* Get link pointer (optimization). */
 1300         link = &priv->links[linkNum];
 1301 
 1302         /* Check link status (if real). */
 1303         if (link->hook == NULL) {
 1304                 ERROUT(ENETDOWN);
 1305         }
 1306 
 1307         /* Extract mbuf. */
 1308         NGI_GET_M(item, m);
 1309 
 1310         /* Check peer's MRU for this link. */
 1311         mru = link->conf.mru;
 1312         if (mru != 0 && m->m_pkthdr.len > mru) {
 1313                 NG_FREE_M(m);
 1314                 ERROUT(EMSGSIZE);
 1315         }
 1316 
 1317         /* Prepend protocol number, possibly compressed. */
 1318         if ((m = ng_ppp_addproto(m, proto, link->conf.enableProtoComp)) ==
 1319             NULL) {
 1320                 ERROUT(ENOBUFS);
 1321         }
 1322 
 1323         /* Prepend address and control field (unless compressed). */
 1324         if (proto == PROT_LCP || !link->conf.enableACFComp) {
 1325                 if ((m = ng_ppp_prepend(m, &ng_ppp_acf, 2)) == NULL)
 1326                         ERROUT(ENOBUFS);
 1327         }
 1328 
 1329         /* Deliver frame. */
 1330         len = m->m_pkthdr.len;
 1331         NG_FWD_NEW_DATA(error, item, link->hook, m);
 1332 
 1333         mtx_lock(&priv->xmtx);
 1334 
 1335         /* Update link stats. */
 1336         link->stats.xmitFrames++;
 1337         link->stats.xmitOctets += len;
 1338 
 1339         /* Update bundle stats. */
 1340         if (plen > 0) {
 1341             priv->bundleStats.xmitFrames++;
 1342             priv->bundleStats.xmitOctets += plen;
 1343         }
 1344 
 1345         /* Update 'bytes in queue' counter. */
 1346         if (error == 0) {
 1347                 /* bytesInQueue and lastWrite required only for mp_strategy. */
 1348                 if (priv->conf.enableMultilink && !priv->allLinksEqual &&
 1349                     !priv->conf.enableRoundRobin) {
 1350                         /* If queue was empty, then mark this time. */
 1351                         if (link->bytesInQueue == 0)
 1352                                 getmicrouptime(&link->lastWrite);
 1353                         link->bytesInQueue += len + MP_AVERAGE_LINK_OVERHEAD;
 1354                         /* Limit max queue length to 50 pkts. BW can be defined
 1355                            incorrectly and link may not signal overload. */
 1356                         if (link->bytesInQueue > 50 * 1600)
 1357                                 link->bytesInQueue = 50 * 1600;
 1358                 }
 1359         }
 1360         mtx_unlock(&priv->xmtx);
 1361         return (error);
 1362 
 1363 done:
 1364         NG_FREE_ITEM(item);
 1365         return (error);
 1366 }
 1367 
 1368 /*
 1369  * Receive data on a hook linkX.
 1370  */
 1371 static int
 1372 ng_ppp_rcvdata(hook_p hook, item_p item)
 1373 {
 1374         const node_p node = NG_HOOK_NODE(hook);
 1375         const priv_p priv = NG_NODE_PRIVATE(node);
 1376         const int index = (intptr_t)NG_HOOK_PRIVATE(hook);
 1377         const uint16_t linkNum = (uint16_t)~index;
 1378         struct ng_ppp_link * const link = &priv->links[linkNum];
 1379         uint16_t proto;
 1380         struct mbuf *m;
 1381         int error = 0;
 1382 
 1383         KASSERT(linkNum < NG_PPP_MAX_LINKS,
 1384             ("%s: bogus index 0x%x", __func__, index));
 1385 
 1386         NGI_GET_M(item, m);
 1387 
 1388         mtx_lock(&priv->rmtx);
 1389 
 1390         /* Stats */
 1391         link->stats.recvFrames++;
 1392         link->stats.recvOctets += m->m_pkthdr.len;
 1393 
 1394         /* Strip address and control fields, if present. */
 1395         if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL)
 1396                 ERROUT(ENOBUFS);
 1397         if (bcmp(mtod(m, uint8_t *), &ng_ppp_acf, 2) == 0)
 1398                 m_adj(m, 2);
 1399 
 1400         /* Get protocol number */
 1401         if ((m = ng_ppp_cutproto(m, &proto)) == NULL)
 1402                 ERROUT(ENOBUFS);
 1403         NGI_M(item) = m;        /* Put changed m back into item. */
 1404 
 1405         if (!PROT_VALID(proto)) {
 1406                 link->stats.badProtos++;
 1407                 ERROUT(EIO);
 1408         }
 1409 
 1410         /* LCP packets must go directly to bypass. */
 1411         if (proto >= 0xB000) {
 1412                 mtx_unlock(&priv->rmtx);
 1413                 return (ng_ppp_bypass(node, item, proto, linkNum));
 1414         }
 1415         
 1416         /* Other packets are denied on a disabled link. */
 1417         if (!link->conf.enableLink)
 1418                 ERROUT(ENXIO);
 1419 
 1420         /* Proceed to multilink layer. Mutex will be unlocked inside. */
 1421         error = ng_ppp_mp_recv(node, item, proto, linkNum);
 1422         mtx_assert(&priv->rmtx, MA_NOTOWNED);
 1423         return (error);
 1424 
 1425 done:
 1426         mtx_unlock(&priv->rmtx);
 1427         NG_FREE_ITEM(item);
 1428         return (error);
 1429 }
 1430 
 1431 /*
 1432  * Multilink layer
 1433  */
 1434 
 1435 /*
 1436  * Handle an incoming multi-link fragment
 1437  *
 1438  * The fragment reassembly algorithm is somewhat complex. This is mainly
 1439  * because we are required not to reorder the reconstructed packets, yet
 1440  * fragments are only guaranteed to arrive in order on a per-link basis.
 1441  * In other words, when we have a complete packet ready, but the previous
 1442  * packet is still incomplete, we have to decide between delivering the
 1443  * complete packet and throwing away the incomplete one, or waiting to
 1444  * see if the remainder of the incomplete one arrives, at which time we
 1445  * can deliver both packets, in order.
 1446  *
 1447  * This problem is exacerbated by "sequence number slew", which is when
 1448  * the sequence numbers coming in from different links are far apart from
 1449  * each other. In particular, certain unnamed equipment (*cough* Ascend)
 1450  * has been seen to generate sequence number slew of up to 10 on an ISDN
 1451  * 2B-channel MP link. There is nothing invalid about sequence number slew
 1452  * but it makes the reasssembly process have to work harder.
 1453  *
 1454  * However, the peer is required to transmit fragments in order on each
 1455  * link. That means if we define MSEQ as the minimum over all links of
 1456  * the highest sequence number received on that link, then we can always
 1457  * give up any hope of receiving a fragment with sequence number < MSEQ in
 1458  * the future (all of this using 'wraparound' sequence number space).
 1459  * Therefore we can always immediately throw away incomplete packets
 1460  * missing fragments with sequence numbers < MSEQ.
 1461  *
 1462  * Here is an overview of our algorithm:
 1463  *
 1464  *    o Received fragments are inserted into a queue, for which we
 1465  *      maintain these invariants between calls to this function:
 1466  *
 1467  *      - Fragments are ordered in the queue by sequence number
 1468  *      - If a complete packet is at the head of the queue, then
 1469  *        the first fragment in the packet has seq# > MSEQ + 1
 1470  *        (otherwise, we could deliver it immediately)
 1471  *      - If any fragments have seq# < MSEQ, then they are necessarily
 1472  *        part of a packet whose missing seq#'s are all > MSEQ (otherwise,
 1473  *        we can throw them away because they'll never be completed)
 1474  *      - The queue contains at most MP_MAX_QUEUE_LEN fragments
 1475  *
 1476  *    o We have a periodic timer that checks the queue for the first
 1477  *      complete packet that has been sitting in the queue "too long".
 1478  *      When one is detected, all previous (incomplete) fragments are
 1479  *      discarded, their missing fragments are declared lost and MSEQ
 1480  *      is increased.
 1481  *
 1482  *    o If we recieve a fragment with seq# < MSEQ, we throw it away
 1483  *      because we've already delcared it lost.
 1484  *
 1485  * This assumes linkNum != NG_PPP_BUNDLE_LINKNUM.
 1486  */
 1487 static int
 1488 ng_ppp_mp_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
 1489 {
 1490         const priv_p priv = NG_NODE_PRIVATE(node);
 1491         struct ng_ppp_link *const link = &priv->links[linkNum];
 1492         struct ng_ppp_frag frag0, *frag = &frag0;
 1493         struct ng_ppp_frag *qent;
 1494         int i, diff, inserted;
 1495         struct mbuf *m;
 1496         int     error = 0;
 1497 
 1498         if ((!priv->conf.enableMultilink) || proto != PROT_MP) {
 1499                 /* Stats */
 1500                 priv->bundleStats.recvFrames++;
 1501                 priv->bundleStats.recvOctets += NGI_M(item)->m_pkthdr.len;
 1502 
 1503                 mtx_unlock(&priv->rmtx);
 1504                 return (ng_ppp_crypt_recv(node, item, proto, linkNum));
 1505         }
 1506 
 1507         NGI_GET_M(item, m);
 1508         NG_FREE_ITEM(item);
 1509 
 1510         /* Extract fragment information from MP header */
 1511         if (priv->conf.recvShortSeq) {
 1512                 uint16_t shdr;
 1513 
 1514                 if (m->m_pkthdr.len < 2) {
 1515                         link->stats.runts++;
 1516                         NG_FREE_M(m);
 1517                         ERROUT(EINVAL);
 1518                 }
 1519                 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL)
 1520                         ERROUT(ENOBUFS);
 1521 
 1522                 shdr = ntohs(*mtod(m, uint16_t *));
 1523                 frag->seq = MP_SHORT_EXTEND(shdr);
 1524                 frag->first = (shdr & MP_SHORT_FIRST_FLAG) != 0;
 1525                 frag->last = (shdr & MP_SHORT_LAST_FLAG) != 0;
 1526                 diff = MP_SHORT_SEQ_DIFF(frag->seq, priv->mseq);
 1527                 m_adj(m, 2);
 1528         } else {
 1529                 uint32_t lhdr;
 1530 
 1531                 if (m->m_pkthdr.len < 4) {
 1532                         link->stats.runts++;
 1533                         NG_FREE_M(m);
 1534                         ERROUT(EINVAL);
 1535                 }
 1536                 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL)
 1537                         ERROUT(ENOBUFS);
 1538 
 1539                 lhdr = ntohl(*mtod(m, uint32_t *));
 1540                 frag->seq = MP_LONG_EXTEND(lhdr);
 1541                 frag->first = (lhdr & MP_LONG_FIRST_FLAG) != 0;
 1542                 frag->last = (lhdr & MP_LONG_LAST_FLAG) != 0;
 1543                 diff = MP_LONG_SEQ_DIFF(frag->seq, priv->mseq);
 1544                 m_adj(m, 4);
 1545         }
 1546         frag->data = m;
 1547         getmicrouptime(&frag->timestamp);
 1548 
 1549         /* If sequence number is < MSEQ, we've already declared this
 1550            fragment as lost, so we have no choice now but to drop it */
 1551         if (diff < 0) {
 1552                 link->stats.dropFragments++;
 1553                 NG_FREE_M(m);
 1554                 ERROUT(0);
 1555         }
 1556 
 1557         /* Update highest received sequence number on this link and MSEQ */
 1558         priv->mseq = link->seq = frag->seq;
 1559         for (i = 0; i < priv->numActiveLinks; i++) {
 1560                 struct ng_ppp_link *const alink =
 1561                     &priv->links[priv->activeLinks[i]];
 1562 
 1563                 if (MP_RECV_SEQ_DIFF(priv, alink->seq, priv->mseq) < 0)
 1564                         priv->mseq = alink->seq;
 1565         }
 1566 
 1567         /* Allocate a new frag struct for the queue */
 1568         MALLOC(frag, struct ng_ppp_frag *, sizeof(*frag), M_NETGRAPH_PPP, M_NOWAIT);
 1569         if (frag == NULL) {
 1570                 NG_FREE_M(m);
 1571                 goto process;
 1572         }
 1573         *frag = frag0;
 1574 
 1575         /* Add fragment to queue, which is sorted by sequence number */
 1576         inserted = 0;
 1577         TAILQ_FOREACH_REVERSE(qent, &priv->frags, ng_ppp_fraglist, f_qent) {
 1578                 diff = MP_RECV_SEQ_DIFF(priv, frag->seq, qent->seq);
 1579                 if (diff > 0) {
 1580                         TAILQ_INSERT_AFTER(&priv->frags, qent, frag, f_qent);
 1581                         inserted = 1;
 1582                         break;
 1583                 } else if (diff == 0) {      /* should never happen! */
 1584                         link->stats.dupFragments++;
 1585                         NG_FREE_M(frag->data);
 1586                         FREE(frag, M_NETGRAPH_PPP);
 1587                         ERROUT(EINVAL);
 1588                 }
 1589         }
 1590         if (!inserted)
 1591                 TAILQ_INSERT_HEAD(&priv->frags, frag, f_qent);
 1592         priv->qlen++;
 1593 
 1594 process:
 1595         /* Process the queue */
 1596         /* NOTE: rmtx will be unlocked for sending time! */
 1597         error = ng_ppp_frag_process(node);
 1598 
 1599 done:
 1600         mtx_unlock(&priv->rmtx);
 1601         return (error);
 1602 }
 1603 
 1604 /************************************************************************
 1605                         HELPER STUFF
 1606  ************************************************************************/
 1607 
 1608 /*
 1609  * If new mseq > current then set it and update all active links
 1610  */
 1611 static void
 1612 ng_ppp_bump_mseq(node_p node, int32_t new_mseq)
 1613 {
 1614         const priv_p priv = NG_NODE_PRIVATE(node);
 1615         int i;
 1616         
 1617         if (MP_RECV_SEQ_DIFF(priv, priv->mseq, new_mseq) < 0) {
 1618                 priv->mseq = new_mseq;
 1619                 for (i = 0; i < priv->numActiveLinks; i++) {
 1620                         struct ng_ppp_link *const alink =
 1621                             &priv->links[priv->activeLinks[i]];
 1622 
 1623                         if (MP_RECV_SEQ_DIFF(priv,
 1624                             alink->seq, new_mseq) < 0)
 1625                                 alink->seq = new_mseq;
 1626                 }
 1627         }
 1628 }
 1629 
 1630 /*
 1631  * Examine our list of fragments, and determine if there is a
 1632  * complete and deliverable packet at the head of the list.
 1633  * Return 1 if so, zero otherwise.
 1634  */
 1635 static int
 1636 ng_ppp_check_packet(node_p node)
 1637 {
 1638         const priv_p priv = NG_NODE_PRIVATE(node);
 1639         struct ng_ppp_frag *qent, *qnext;
 1640 
 1641         /* Check for empty queue */
 1642         if (TAILQ_EMPTY(&priv->frags))
 1643                 return (0);
 1644 
 1645         /* Check first fragment is the start of a deliverable packet */
 1646         qent = TAILQ_FIRST(&priv->frags);
 1647         if (!qent->first || MP_RECV_SEQ_DIFF(priv, qent->seq, priv->mseq) > 1)
 1648                 return (0);
 1649 
 1650         /* Check that all the fragments are there */
 1651         while (!qent->last) {
 1652                 qnext = TAILQ_NEXT(qent, f_qent);
 1653                 if (qnext == NULL)      /* end of queue */
 1654                         return (0);
 1655                 if (qnext->seq != MP_NEXT_RECV_SEQ(priv, qent->seq))
 1656                         return (0);
 1657                 qent = qnext;
 1658         }
 1659 
 1660         /* Got one */
 1661         return (1);
 1662 }
 1663 
 1664 /*
 1665  * Pull a completed packet off the head of the incoming fragment queue.
 1666  * This assumes there is a completed packet there to pull off.
 1667  */
 1668 static void
 1669 ng_ppp_get_packet(node_p node, struct mbuf **mp)
 1670 {
 1671         const priv_p priv = NG_NODE_PRIVATE(node);
 1672         struct ng_ppp_frag *qent, *qnext;
 1673         struct mbuf *m = NULL, *tail;
 1674 
 1675         qent = TAILQ_FIRST(&priv->frags);
 1676         KASSERT(!TAILQ_EMPTY(&priv->frags) && qent->first,
 1677             ("%s: no packet", __func__));
 1678         for (tail = NULL; qent != NULL; qent = qnext) {
 1679                 qnext = TAILQ_NEXT(qent, f_qent);
 1680                 KASSERT(!TAILQ_EMPTY(&priv->frags),
 1681                     ("%s: empty q", __func__));
 1682                 TAILQ_REMOVE(&priv->frags, qent, f_qent);
 1683                 if (tail == NULL)
 1684                         tail = m = qent->data;
 1685                 else {
 1686                         m->m_pkthdr.len += qent->data->m_pkthdr.len;
 1687                         tail->m_next = qent->data;
 1688                 }
 1689                 while (tail->m_next != NULL)
 1690                         tail = tail->m_next;
 1691                 if (qent->last) {
 1692                         qnext = NULL;
 1693                         /* Bump MSEQ if necessary */
 1694                         ng_ppp_bump_mseq(node, qent->seq);
 1695                 }
 1696                 FREE(qent, M_NETGRAPH_PPP);
 1697                 priv->qlen--;
 1698         }
 1699         *mp = m;
 1700 }
 1701 
 1702 /*
 1703  * Trim fragments from the queue whose packets can never be completed.
 1704  * This assumes a complete packet is NOT at the beginning of the queue.
 1705  * Returns 1 if fragments were removed, zero otherwise.
 1706  */
 1707 static int
 1708 ng_ppp_frag_trim(node_p node)
 1709 {
 1710         const priv_p priv = NG_NODE_PRIVATE(node);
 1711         struct ng_ppp_frag *qent, *qnext = NULL;
 1712         int removed = 0;
 1713 
 1714         /* Scan for "dead" fragments and remove them */
 1715         while (1) {
 1716                 int dead = 0;
 1717 
 1718                 /* If queue is empty, we're done */
 1719                 if (TAILQ_EMPTY(&priv->frags))
 1720                         break;
 1721 
 1722                 /* Determine whether first fragment can ever be completed */
 1723                 TAILQ_FOREACH(qent, &priv->frags, f_qent) {
 1724                         if (MP_RECV_SEQ_DIFF(priv, qent->seq, priv->mseq) >= 0)
 1725                                 break;
 1726                         qnext = TAILQ_NEXT(qent, f_qent);
 1727                         KASSERT(qnext != NULL,
 1728                             ("%s: last frag < MSEQ?", __func__));
 1729                         if (qnext->seq != MP_NEXT_RECV_SEQ(priv, qent->seq)
 1730                             || qent->last || qnext->first) {
 1731                                 dead = 1;
 1732                                 break;
 1733                         }
 1734                 }
 1735                 if (!dead)
 1736                         break;
 1737 
 1738                 /* Remove fragment and all others in the same packet */
 1739                 while ((qent = TAILQ_FIRST(&priv->frags)) != qnext) {
 1740                         KASSERT(!TAILQ_EMPTY(&priv->frags),
 1741                             ("%s: empty q", __func__));
 1742                         priv->bundleStats.dropFragments++;
 1743                         TAILQ_REMOVE(&priv->frags, qent, f_qent);
 1744                         NG_FREE_M(qent->data);
 1745                         FREE(qent, M_NETGRAPH_PPP);
 1746                         priv->qlen--;
 1747                         removed = 1;
 1748                 }
 1749         }
 1750         return (removed);
 1751 }
 1752 
 1753 /*
 1754  * Drop fragments on queue overflow.
 1755  * Returns 1 if fragments were removed, zero otherwise.
 1756  */
 1757 static int
 1758 ng_ppp_frag_drop(node_p node)
 1759 {
 1760         const priv_p priv = NG_NODE_PRIVATE(node);
 1761 
 1762         /* Check queue length */
 1763         if (priv->qlen > MP_MAX_QUEUE_LEN) {
 1764                 struct ng_ppp_frag *qent;
 1765 
 1766                 /* Get oldest fragment */
 1767                 KASSERT(!TAILQ_EMPTY(&priv->frags),
 1768                     ("%s: empty q", __func__));
 1769                 qent = TAILQ_FIRST(&priv->frags);
 1770 
 1771                 /* Bump MSEQ if necessary */
 1772                 ng_ppp_bump_mseq(node, qent->seq);
 1773 
 1774                 /* Drop it */
 1775                 priv->bundleStats.dropFragments++;
 1776                 TAILQ_REMOVE(&priv->frags, qent, f_qent);
 1777                 NG_FREE_M(qent->data);
 1778                 FREE(qent, M_NETGRAPH_PPP);
 1779                 priv->qlen--;
 1780 
 1781                 return (1);
 1782         }
 1783         return (0);
 1784 }
 1785 
 1786 /*
 1787  * Run the queue, restoring the queue invariants
 1788  */
 1789 static int
 1790 ng_ppp_frag_process(node_p node)
 1791 {
 1792         const priv_p priv = NG_NODE_PRIVATE(node);
 1793         struct mbuf *m;
 1794         item_p item;
 1795         uint16_t proto;
 1796 
 1797         do {
 1798                 /* Deliver any deliverable packets */
 1799                 while (ng_ppp_check_packet(node)) {
 1800                         ng_ppp_get_packet(node, &m);
 1801                         if ((m = ng_ppp_cutproto(m, &proto)) == NULL)
 1802                                 continue;
 1803                         if (!PROT_VALID(proto)) {
 1804                                 priv->bundleStats.badProtos++;
 1805                                 NG_FREE_M(m);
 1806                                 continue;
 1807                         }
 1808                         if ((item = ng_package_data(m, NG_NOFLAGS)) != NULL) {
 1809                                 /* Stats */
 1810                                 priv->bundleStats.recvFrames++;
 1811                                 priv->bundleStats.recvOctets += 
 1812                                     NGI_M(item)->m_pkthdr.len;
 1813 
 1814                                 /* Drop mutex for the sending time.
 1815                                  * Priv may change, but we are ready!
 1816                                  */
 1817                                 mtx_unlock(&priv->rmtx);
 1818                                 ng_ppp_crypt_recv(node, item, proto,
 1819                                         NG_PPP_BUNDLE_LINKNUM);
 1820                                 mtx_lock(&priv->rmtx);
 1821                         }
 1822                 }
 1823           /* Delete dead fragments and try again */
 1824         } while (ng_ppp_frag_trim(node) || ng_ppp_frag_drop(node));
 1825 
 1826         /* Done */
 1827         return (0);
 1828 }
 1829 
 1830 /*
 1831  * Check for 'stale' completed packets that need to be delivered
 1832  *
 1833  * If a link goes down or has a temporary failure, MSEQ can get
 1834  * "stuck", because no new incoming fragments appear on that link.
 1835  * This can cause completed packets to never get delivered if
 1836  * their sequence numbers are all > MSEQ + 1.
 1837  *
 1838  * This routine checks how long all of the completed packets have
 1839  * been sitting in the queue, and if too long, removes fragments
 1840  * from the queue and increments MSEQ to allow them to be delivered.
 1841  */
 1842 static void
 1843 ng_ppp_frag_checkstale(node_p node)
 1844 {
 1845         const priv_p priv = NG_NODE_PRIVATE(node);
 1846         struct ng_ppp_frag *qent, *beg, *end;
 1847         struct timeval now, age;
 1848         struct mbuf *m;
 1849         int seq;
 1850         item_p item;
 1851         int endseq;
 1852         uint16_t proto;
 1853 
 1854         now.tv_sec = 0;                 /* uninitialized state */
 1855         while (1) {
 1856 
 1857                 /* If queue is empty, we're done */
 1858                 if (TAILQ_EMPTY(&priv->frags))
 1859                         break;
 1860 
 1861                 /* Find the first complete packet in the queue */
 1862                 beg = end = NULL;
 1863                 seq = TAILQ_FIRST(&priv->frags)->seq;
 1864                 TAILQ_FOREACH(qent, &priv->frags, f_qent) {
 1865                         if (qent->first)
 1866                                 beg = qent;
 1867                         else if (qent->seq != seq)
 1868                                 beg = NULL;
 1869                         if (beg != NULL && qent->last) {
 1870                                 end = qent;
 1871                                 break;
 1872                         }
 1873                         seq = MP_NEXT_RECV_SEQ(priv, seq);
 1874                 }
 1875 
 1876                 /* If none found, exit */
 1877                 if (end == NULL)
 1878                         break;
 1879 
 1880                 /* Get current time (we assume we've been up for >= 1 second) */
 1881                 if (now.tv_sec == 0)
 1882                         getmicrouptime(&now);
 1883 
 1884                 /* Check if packet has been queued too long */
 1885                 age = now;
 1886                 timevalsub(&age, &beg->timestamp);
 1887                 if (timevalcmp(&age, &ng_ppp_max_staleness, < ))
 1888                         break;
 1889 
 1890                 /* Throw away junk fragments in front of the completed packet */
 1891                 while ((qent = TAILQ_FIRST(&priv->frags)) != beg) {
 1892                         KASSERT(!TAILQ_EMPTY(&priv->frags),
 1893                             ("%s: empty q", __func__));
 1894                         priv->bundleStats.dropFragments++;
 1895                         TAILQ_REMOVE(&priv->frags, qent, f_qent);
 1896                         NG_FREE_M(qent->data);
 1897                         FREE(qent, M_NETGRAPH_PPP);
 1898                         priv->qlen--;
 1899                 }
 1900 
 1901                 /* Extract completed packet */
 1902                 endseq = end->seq;
 1903                 ng_ppp_get_packet(node, &m);
 1904 
 1905                 if ((m = ng_ppp_cutproto(m, &proto)) == NULL)
 1906                         continue;
 1907                 if (!PROT_VALID(proto)) {
 1908                         priv->bundleStats.badProtos++;
 1909                         NG_FREE_M(m);
 1910                         continue;
 1911                 }
 1912 
 1913                 /* Deliver packet */
 1914                 if ((item = ng_package_data(m, NG_NOFLAGS)) != NULL) {
 1915                         /* Stats */
 1916                         priv->bundleStats.recvFrames++;
 1917                         priv->bundleStats.recvOctets += NGI_M(item)->m_pkthdr.len;
 1918 
 1919                         ng_ppp_crypt_recv(node, item, proto,
 1920                                 NG_PPP_BUNDLE_LINKNUM);
 1921                 }
 1922         }
 1923 }
 1924 
 1925 /*
 1926  * Periodically call ng_ppp_frag_checkstale()
 1927  */
 1928 static void
 1929 ng_ppp_frag_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 1930 {
 1931         /* XXX: is this needed? */
 1932         if (NG_NODE_NOT_VALID(node))
 1933                 return;
 1934 
 1935         /* Scan the fragment queue */
 1936         ng_ppp_frag_checkstale(node);
 1937 
 1938         /* Start timer again */
 1939         ng_ppp_start_frag_timer(node);
 1940 }
 1941 
 1942 /*
 1943  * Deliver a frame out on the bundle, i.e., figure out how to fragment
 1944  * the frame across the individual PPP links and do so.
 1945  */
 1946 static int
 1947 ng_ppp_mp_xmit(node_p node, item_p item, uint16_t proto)
 1948 {
 1949         const priv_p priv = NG_NODE_PRIVATE(node);
 1950         const int hdr_len = priv->conf.xmitShortSeq ? 2 : 4;
 1951         int distrib[NG_PPP_MAX_LINKS];
 1952         int firstFragment;
 1953         int activeLinkNum;
 1954         struct mbuf *m;
 1955         int     plen;
 1956         int     frags;
 1957         int32_t seq;
 1958 
 1959         /* At least one link must be active */
 1960         if (priv->numActiveLinks == 0) {
 1961                 NG_FREE_ITEM(item);
 1962                 return (ENETDOWN);
 1963         }
 1964         
 1965         /* Save length for later stats. */
 1966         plen = NGI_M(item)->m_pkthdr.len;
 1967 
 1968         if (!priv->conf.enableMultilink) {
 1969                 return (ng_ppp_link_xmit(node, item, proto,
 1970                     priv->activeLinks[0], plen));
 1971         }
 1972 
 1973         /* Extract mbuf. */
 1974         NGI_GET_M(item, m);
 1975         NG_FREE_ITEM(item);
 1976 
 1977         /* Prepend protocol number, possibly compressed. */
 1978         if ((m = ng_ppp_addproto(m, proto, 1)) == NULL)
 1979                 return (ENOBUFS);
 1980 
 1981         /* Clear distribution plan */
 1982         bzero(&distrib, priv->numActiveLinks * sizeof(distrib[0]));
 1983 
 1984         mtx_lock(&priv->xmtx);
 1985 
 1986         /* Round-robin strategy */
 1987         if (priv->conf.enableRoundRobin) {
 1988                 activeLinkNum = priv->lastLink++ % priv->numActiveLinks;
 1989                 distrib[activeLinkNum] = m->m_pkthdr.len;
 1990                 goto deliver;
 1991         }
 1992 
 1993         /* Strategy when all links are equivalent (optimize the common case) */
 1994         if (priv->allLinksEqual) {
 1995                 int     numFrags, fraction, remain;
 1996                 int     i;
 1997                 
 1998                 /* Calculate optimal fragment count */
 1999                 numFrags = priv->numActiveLinks;
 2000                 if (numFrags > m->m_pkthdr.len / MP_MIN_FRAG_LEN)
 2001                     numFrags = m->m_pkthdr.len / MP_MIN_FRAG_LEN;
 2002                 if (numFrags == 0)
 2003                     numFrags = 1;
 2004 
 2005                 fraction = m->m_pkthdr.len / numFrags;
 2006                 remain = m->m_pkthdr.len - (fraction * numFrags);
 2007                 
 2008                 /* Assign distribution */
 2009                 for (i = 0; i < numFrags; i++) {
 2010                         distrib[priv->lastLink++ % priv->numActiveLinks]
 2011                             = fraction + (((remain--) > 0)?1:0);
 2012                 }
 2013                 goto deliver;
 2014         }
 2015 
 2016         /* Strategy when all links are not equivalent */
 2017         ng_ppp_mp_strategy(node, m->m_pkthdr.len, distrib);
 2018 
 2019 deliver:
 2020         /* Estimate fragments count */
 2021         frags = 0;
 2022         for (activeLinkNum = priv->numActiveLinks - 1;
 2023             activeLinkNum >= 0; activeLinkNum--) {
 2024                 const uint16_t linkNum = priv->activeLinks[activeLinkNum];
 2025                 struct ng_ppp_link *const link = &priv->links[linkNum];
 2026                 
 2027                 frags += (distrib[activeLinkNum] + link->conf.mru - hdr_len - 1) /
 2028                     (link->conf.mru - hdr_len);
 2029         }
 2030         
 2031         /* Get out initial sequence number */
 2032         seq = priv->xseq;
 2033 
 2034         /* Update next sequence number */
 2035         if (priv->conf.xmitShortSeq) {
 2036             priv->xseq = (seq + frags) & MP_SHORT_SEQ_MASK;
 2037         } else {
 2038             priv->xseq = (seq + frags) & MP_LONG_SEQ_MASK;
 2039         }
 2040 
 2041         mtx_unlock(&priv->xmtx);
 2042 
 2043         /* Send alloted portions of frame out on the link(s) */
 2044         for (firstFragment = 1, activeLinkNum = priv->numActiveLinks - 1;
 2045             activeLinkNum >= 0; activeLinkNum--) {
 2046                 const uint16_t linkNum = priv->activeLinks[activeLinkNum];
 2047                 struct ng_ppp_link *const link = &priv->links[linkNum];
 2048 
 2049                 /* Deliver fragment(s) out the next link */
 2050                 for ( ; distrib[activeLinkNum] > 0; firstFragment = 0) {
 2051                         int len, lastFragment, error;
 2052                         struct mbuf *m2;
 2053 
 2054                         /* Calculate fragment length; don't exceed link MTU */
 2055                         len = distrib[activeLinkNum];
 2056                         if (len > link->conf.mru - hdr_len)
 2057                                 len = link->conf.mru - hdr_len;
 2058                         distrib[activeLinkNum] -= len;
 2059                         lastFragment = (len == m->m_pkthdr.len);
 2060 
 2061                         /* Split off next fragment as "m2" */
 2062                         m2 = m;
 2063                         if (!lastFragment) {
 2064                                 struct mbuf *n = m_split(m, len, M_DONTWAIT);
 2065 
 2066                                 if (n == NULL) {
 2067                                         NG_FREE_M(m);
 2068                                         return (ENOMEM);
 2069                                 }
 2070                                 m_tag_copy_chain(n, m, M_DONTWAIT);
 2071                                 m = n;
 2072                         }
 2073 
 2074                         /* Prepend MP header */
 2075                         if (priv->conf.xmitShortSeq) {
 2076                                 uint16_t shdr;
 2077 
 2078                                 shdr = seq;
 2079                                 seq = (seq + 1) & MP_SHORT_SEQ_MASK;
 2080                                 if (firstFragment)
 2081                                         shdr |= MP_SHORT_FIRST_FLAG;
 2082                                 if (lastFragment)
 2083                                         shdr |= MP_SHORT_LAST_FLAG;
 2084                                 shdr = htons(shdr);
 2085                                 m2 = ng_ppp_prepend(m2, &shdr, 2);
 2086                         } else {
 2087                                 uint32_t lhdr;
 2088 
 2089                                 lhdr = seq;
 2090                                 seq = (seq + 1) & MP_LONG_SEQ_MASK;
 2091                                 if (firstFragment)
 2092                                         lhdr |= MP_LONG_FIRST_FLAG;
 2093                                 if (lastFragment)
 2094                                         lhdr |= MP_LONG_LAST_FLAG;
 2095                                 lhdr = htonl(lhdr);
 2096                                 m2 = ng_ppp_prepend(m2, &lhdr, 4);
 2097                         }
 2098                         if (m2 == NULL) {
 2099                                 if (!lastFragment)
 2100                                         m_freem(m);
 2101                                 return (ENOBUFS);
 2102                         }
 2103 
 2104                         /* Send fragment */
 2105                         if ((item = ng_package_data(m2, NG_NOFLAGS)) != NULL) {
 2106                                 error = ng_ppp_link_xmit(node, item, PROT_MP,
 2107                                             linkNum, (firstFragment?plen:0));
 2108                                 if (error != 0) {
 2109                                         if (!lastFragment)
 2110                                                 NG_FREE_M(m);
 2111                                         return (error);
 2112                                 }
 2113                         }
 2114                 }
 2115         }
 2116 
 2117         /* Done */
 2118         return (0);
 2119 }
 2120 
 2121 /*
 2122  * Computing the optimal fragmentation
 2123  * -----------------------------------
 2124  *
 2125  * This routine tries to compute the optimal fragmentation pattern based
 2126  * on each link's latency, bandwidth, and calculated additional latency.
 2127  * The latter quantity is the additional latency caused by previously
 2128  * written data that has not been transmitted yet.
 2129  *
 2130  * This algorithm is only useful when not all of the links have the
 2131  * same latency and bandwidth values.
 2132  *
 2133  * The essential idea is to make the last bit of each fragment of the
 2134  * frame arrive at the opposite end at the exact same time. This greedy
 2135  * algorithm is optimal, in that no other scheduling could result in any
 2136  * packet arriving any sooner unless packets are delivered out of order.
 2137  *
 2138  * Suppose link i has bandwidth b_i (in tens of bytes per milisecond) and
 2139  * latency l_i (in miliseconds). Consider the function function f_i(t)
 2140  * which is equal to the number of bytes that will have arrived at
 2141  * the peer after t miliseconds if we start writing continuously at
 2142  * time t = 0. Then f_i(t) = b_i * (t - l_i) = ((b_i * t) - (l_i * b_i).
 2143  * That is, f_i(t) is a line with slope b_i and y-intersect -(l_i * b_i).
 2144  * Note that the y-intersect is always <= zero because latency can't be
 2145  * negative.  Note also that really the function is f_i(t) except when
 2146  * f_i(t) is negative, in which case the function is zero.  To take
 2147  * care of this, let Q_i(t) = { if (f_i(t) > 0) return 1; else return 0; }.
 2148  * So the actual number of bytes that will have arrived at the peer after
 2149  * t miliseconds is f_i(t) * Q_i(t).
 2150  *
 2151  * At any given time, each link has some additional latency a_i >= 0
 2152  * due to previously written fragment(s) which are still in the queue.
 2153  * This value is easily computed from the time since last transmission,
 2154  * the previous latency value, the number of bytes written, and the
 2155  * link's bandwidth.
 2156  *
 2157  * Assume that l_i includes any a_i already, and that the links are
 2158  * sorted by latency, so that l_i <= l_{i+1}.
 2159  *
 2160  * Let N be the total number of bytes in the current frame we are sending.
 2161  *
 2162  * Suppose we were to start writing bytes at time t = 0 on all links
 2163  * simultaneously, which is the most we can possibly do.  Then let
 2164  * F(t) be equal to the total number of bytes received by the peer
 2165  * after t miliseconds. Then F(t) = Sum_i (f_i(t) * Q_i(t)).
 2166  *
 2167  * Our goal is simply this: fragment the frame across the links such
 2168  * that the peer is able to reconstruct the completed frame as soon as
 2169  * possible, i.e., at the least possible value of t. Call this value t_0.
 2170  *
 2171  * Then it follows that F(t_0) = N. Our strategy is first to find the value
 2172  * of t_0, and then deduce how many bytes to write to each link.
 2173  *
 2174  * Rewriting F(t_0):
 2175  *
 2176  *   t_0 = ( N + Sum_i ( l_i * b_i * Q_i(t_0) ) ) / Sum_i ( b_i * Q_i(t_0) )
 2177  *
 2178  * Now, we note that Q_i(t) is constant for l_i <= t <= l_{i+1}. t_0 will
 2179  * lie in one of these ranges.  To find it, we just need to find the i such
 2180  * that F(l_i) <= N <= F(l_{i+1}).  Then we compute all the constant values
 2181  * for Q_i() in this range, plug in the remaining values, solving for t_0.
 2182  *
 2183  * Once t_0 is known, then the number of bytes to send on link i is
 2184  * just f_i(t_0) * Q_i(t_0).
 2185  *
 2186  * In other words, we start allocating bytes to the links one at a time.
 2187  * We keep adding links until the frame is completely sent.  Some links
 2188  * may not get any bytes because their latency is too high.
 2189  *
 2190  * Is all this work really worth the trouble?  Depends on the situation.
 2191  * The bigger the ratio of computer speed to link speed, and the more
 2192  * important total bundle latency is (e.g., for interactive response time),
 2193  * the more it's worth it.  There is however the cost of calling this
 2194  * function for every frame.  The running time is O(n^2) where n is the
 2195  * number of links that receive a non-zero number of bytes.
 2196  *
 2197  * Since latency is measured in miliseconds, the "resolution" of this
 2198  * algorithm is one milisecond.
 2199  *
 2200  * To avoid this algorithm altogether, configure all links to have the
 2201  * same latency and bandwidth.
 2202  */
 2203 static void
 2204 ng_ppp_mp_strategy(node_p node, int len, int *distrib)
 2205 {
 2206         const priv_p priv = NG_NODE_PRIVATE(node);
 2207         int latency[NG_PPP_MAX_LINKS];
 2208         int sortByLatency[NG_PPP_MAX_LINKS];
 2209         int activeLinkNum;
 2210         int t0, total, topSum, botSum;
 2211         struct timeval now;
 2212         int i, numFragments;
 2213 
 2214         /* If only one link, this gets real easy */
 2215         if (priv->numActiveLinks == 1) {
 2216                 distrib[0] = len;
 2217                 return;
 2218         }
 2219 
 2220         /* Get current time */
 2221         getmicrouptime(&now);
 2222 
 2223         /* Compute latencies for each link at this point in time */
 2224         for (activeLinkNum = 0;
 2225             activeLinkNum < priv->numActiveLinks; activeLinkNum++) {
 2226                 struct ng_ppp_link *alink;
 2227                 struct timeval diff;
 2228                 int xmitBytes;
 2229 
 2230                 /* Start with base latency value */
 2231                 alink = &priv->links[priv->activeLinks[activeLinkNum]];
 2232                 latency[activeLinkNum] = alink->latency;
 2233                 sortByLatency[activeLinkNum] = activeLinkNum;   /* see below */
 2234 
 2235                 /* Any additional latency? */
 2236                 if (alink->bytesInQueue == 0)
 2237                         continue;
 2238 
 2239                 /* Compute time delta since last write */
 2240                 diff = now;
 2241                 timevalsub(&diff, &alink->lastWrite);
 2242                 
 2243                 /* alink->bytesInQueue will be changed, mark change time. */
 2244                 alink->lastWrite = now;
 2245 
 2246                 if (now.tv_sec < 0 || diff.tv_sec >= 10) {      /* sanity */
 2247                         alink->bytesInQueue = 0;
 2248                         continue;
 2249                 }
 2250 
 2251                 /* How many bytes could have transmitted since last write? */
 2252                 xmitBytes = (alink->conf.bandwidth * 10 * diff.tv_sec)
 2253                     + (alink->conf.bandwidth * (diff.tv_usec / 1000)) / 100;
 2254                 alink->bytesInQueue -= xmitBytes;
 2255                 if (alink->bytesInQueue < 0)
 2256                         alink->bytesInQueue = 0;
 2257                 else
 2258                         latency[activeLinkNum] +=
 2259                             (100 * alink->bytesInQueue) / alink->conf.bandwidth;
 2260         }
 2261 
 2262         /* Sort active links by latency */
 2263         qsort_r(sortByLatency,
 2264             priv->numActiveLinks, sizeof(*sortByLatency), latency, ng_ppp_intcmp);
 2265 
 2266         /* Find the interval we need (add links in sortByLatency[] order) */
 2267         for (numFragments = 1;
 2268             numFragments < priv->numActiveLinks; numFragments++) {
 2269                 for (total = i = 0; i < numFragments; i++) {
 2270                         int flowTime;
 2271 
 2272                         flowTime = latency[sortByLatency[numFragments]]
 2273                             - latency[sortByLatency[i]];
 2274                         total += ((flowTime * priv->links[
 2275                             priv->activeLinks[sortByLatency[i]]].conf.bandwidth)
 2276                                 + 99) / 100;
 2277                 }
 2278                 if (total >= len)
 2279                         break;
 2280         }
 2281 
 2282         /* Solve for t_0 in that interval */
 2283         for (topSum = botSum = i = 0; i < numFragments; i++) {
 2284                 int bw = priv->links[
 2285                     priv->activeLinks[sortByLatency[i]]].conf.bandwidth;
 2286 
 2287                 topSum += latency[sortByLatency[i]] * bw;       /* / 100 */
 2288                 botSum += bw;                                   /* / 100 */
 2289         }
 2290         t0 = ((len * 100) + topSum + botSum / 2) / botSum;
 2291 
 2292         /* Compute f_i(t_0) all i */
 2293         for (total = i = 0; i < numFragments; i++) {
 2294                 int bw = priv->links[
 2295                     priv->activeLinks[sortByLatency[i]]].conf.bandwidth;
 2296 
 2297                 distrib[sortByLatency[i]] =
 2298                     (bw * (t0 - latency[sortByLatency[i]]) + 50) / 100;
 2299                 total += distrib[sortByLatency[i]];
 2300         }
 2301 
 2302         /* Deal with any rounding error */
 2303         if (total < len) {
 2304                 struct ng_ppp_link *fastLink =
 2305                     &priv->links[priv->activeLinks[sortByLatency[0]]];
 2306                 int fast = 0;
 2307 
 2308                 /* Find the fastest link */
 2309                 for (i = 1; i < numFragments; i++) {
 2310                         struct ng_ppp_link *const link =
 2311                             &priv->links[priv->activeLinks[sortByLatency[i]]];
 2312 
 2313                         if (link->conf.bandwidth > fastLink->conf.bandwidth) {
 2314                                 fast = i;
 2315                                 fastLink = link;
 2316                         }
 2317                 }
 2318                 distrib[sortByLatency[fast]] += len - total;
 2319         } else while (total > len) {
 2320                 struct ng_ppp_link *slowLink =
 2321                     &priv->links[priv->activeLinks[sortByLatency[0]]];
 2322                 int delta, slow = 0;
 2323 
 2324                 /* Find the slowest link that still has bytes to remove */
 2325                 for (i = 1; i < numFragments; i++) {
 2326                         struct ng_ppp_link *const link =
 2327                             &priv->links[priv->activeLinks[sortByLatency[i]]];
 2328 
 2329                         if (distrib[sortByLatency[slow]] == 0
 2330                           || (distrib[sortByLatency[i]] > 0
 2331                             && link->conf.bandwidth <
 2332                               slowLink->conf.bandwidth)) {
 2333                                 slow = i;
 2334                                 slowLink = link;
 2335                         }
 2336                 }
 2337                 delta = total - len;
 2338                 if (delta > distrib[sortByLatency[slow]])
 2339                         delta = distrib[sortByLatency[slow]];
 2340                 distrib[sortByLatency[slow]] -= delta;
 2341                 total -= delta;
 2342         }
 2343 }
 2344 
 2345 /*
 2346  * Compare two integers
 2347  */
 2348 static int
 2349 ng_ppp_intcmp(void *latency, const void *v1, const void *v2)
 2350 {
 2351         const int index1 = *((const int *) v1);
 2352         const int index2 = *((const int *) v2);
 2353 
 2354         return ((int *)latency)[index1] - ((int *)latency)[index2];
 2355 }
 2356 
 2357 /*
 2358  * Prepend a possibly compressed PPP protocol number in front of a frame
 2359  */
 2360 static struct mbuf *
 2361 ng_ppp_addproto(struct mbuf *m, uint16_t proto, int compOK)
 2362 {
 2363         if (compOK && PROT_COMPRESSABLE(proto)) {
 2364                 uint8_t pbyte = (uint8_t)proto;
 2365 
 2366                 return ng_ppp_prepend(m, &pbyte, 1);
 2367         } else {
 2368                 uint16_t pword = htons((uint16_t)proto);
 2369 
 2370                 return ng_ppp_prepend(m, &pword, 2);
 2371         }
 2372 }
 2373 
 2374 /*
 2375  * Cut a possibly compressed PPP protocol number from the front of a frame.
 2376  */
 2377 static struct mbuf *
 2378 ng_ppp_cutproto(struct mbuf *m, uint16_t *proto)
 2379 {
 2380 
 2381         *proto = 0;
 2382         if (m->m_len < 1 && (m = m_pullup(m, 1)) == NULL)
 2383                 return (NULL);
 2384 
 2385         *proto = *mtod(m, uint8_t *);
 2386         m_adj(m, 1);
 2387 
 2388         if (!PROT_VALID(*proto)) {
 2389                 if (m->m_len < 1 && (m = m_pullup(m, 1)) == NULL)
 2390                         return (NULL);
 2391 
 2392                 *proto = (*proto << 8) + *mtod(m, uint8_t *);
 2393                 m_adj(m, 1);
 2394         }
 2395 
 2396         return (m);
 2397 }
 2398 
 2399 /*
 2400  * Prepend some bytes to an mbuf.
 2401  */
 2402 static struct mbuf *
 2403 ng_ppp_prepend(struct mbuf *m, const void *buf, int len)
 2404 {
 2405         M_PREPEND(m, len, M_DONTWAIT);
 2406         if (m == NULL || (m->m_len < len && (m = m_pullup(m, len)) == NULL))
 2407                 return (NULL);
 2408         bcopy(buf, mtod(m, uint8_t *), len);
 2409         return (m);
 2410 }
 2411 
 2412 /*
 2413  * Update private information that is derived from other private information
 2414  */
 2415 static void
 2416 ng_ppp_update(node_p node, int newConf)
 2417 {
 2418         const priv_p priv = NG_NODE_PRIVATE(node);
 2419         int i;
 2420 
 2421         /* Update active status for VJ Compression */
 2422         priv->vjCompHooked = priv->hooks[HOOK_INDEX_VJC_IP] != NULL
 2423             && priv->hooks[HOOK_INDEX_VJC_COMP] != NULL
 2424             && priv->hooks[HOOK_INDEX_VJC_UNCOMP] != NULL
 2425             && priv->hooks[HOOK_INDEX_VJC_VJIP] != NULL;
 2426 
 2427         /* Increase latency for each link an amount equal to one MP header */
 2428         if (newConf) {
 2429                 for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
 2430                         int hdrBytes;
 2431 
 2432                         if (priv->links[i].conf.bandwidth == 0)
 2433                             continue;
 2434                             
 2435                         hdrBytes = MP_AVERAGE_LINK_OVERHEAD
 2436                             + (priv->links[i].conf.enableACFComp ? 0 : 2)
 2437                             + (priv->links[i].conf.enableProtoComp ? 1 : 2)
 2438                             + (priv->conf.xmitShortSeq ? 2 : 4);
 2439                         priv->links[i].latency =
 2440                             priv->links[i].conf.latency +
 2441                             (hdrBytes / priv->links[i].conf.bandwidth + 50) / 100;
 2442                 }
 2443         }
 2444 
 2445         /* Update list of active links */
 2446         bzero(&priv->activeLinks, sizeof(priv->activeLinks));
 2447         priv->numActiveLinks = 0;
 2448         priv->allLinksEqual = 1;
 2449         for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
 2450                 struct ng_ppp_link *const link = &priv->links[i];
 2451 
 2452                 /* Is link active? */
 2453                 if (link->conf.enableLink && link->hook != NULL) {
 2454                         struct ng_ppp_link *link0;
 2455 
 2456                         /* Add link to list of active links */
 2457                         priv->activeLinks[priv->numActiveLinks++] = i;
 2458                         link0 = &priv->links[priv->activeLinks[0]];
 2459 
 2460                         /* Determine if all links are still equal */
 2461                         if (link->latency != link0->latency
 2462                           || link->conf.bandwidth != link0->conf.bandwidth)
 2463                                 priv->allLinksEqual = 0;
 2464 
 2465                         /* Initialize rec'd sequence number */
 2466                         if (link->seq == MP_NOSEQ) {
 2467                                 link->seq = (link == link0) ?
 2468                                     MP_INITIAL_SEQ : link0->seq;
 2469                         }
 2470                 } else
 2471                         link->seq = MP_NOSEQ;
 2472         }
 2473 
 2474         /* Update MP state as multi-link is active or not */
 2475         if (priv->conf.enableMultilink && priv->numActiveLinks > 0)
 2476                 ng_ppp_start_frag_timer(node);
 2477         else {
 2478                 ng_ppp_stop_frag_timer(node);
 2479                 ng_ppp_frag_reset(node);
 2480                 priv->xseq = MP_INITIAL_SEQ;
 2481                 priv->mseq = MP_INITIAL_SEQ;
 2482                 for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
 2483                         struct ng_ppp_link *const link = &priv->links[i];
 2484 
 2485                         bzero(&link->lastWrite, sizeof(link->lastWrite));
 2486                         link->bytesInQueue = 0;
 2487                         link->seq = MP_NOSEQ;
 2488                 }
 2489         }
 2490 }
 2491 
 2492 /*
 2493  * Determine if a new configuration would represent a valid change
 2494  * from the current configuration and link activity status.
 2495  */
 2496 static int
 2497 ng_ppp_config_valid(node_p node, const struct ng_ppp_node_conf *newConf)
 2498 {
 2499         const priv_p priv = NG_NODE_PRIVATE(node);
 2500         int i, newNumLinksActive;
 2501 
 2502         /* Check per-link config and count how many links would be active */
 2503         for (newNumLinksActive = i = 0; i < NG_PPP_MAX_LINKS; i++) {
 2504                 if (newConf->links[i].enableLink && priv->links[i].hook != NULL)
 2505                         newNumLinksActive++;
 2506                 if (!newConf->links[i].enableLink)
 2507                         continue;
 2508                 if (newConf->links[i].mru < MP_MIN_LINK_MRU)
 2509                         return (0);
 2510                 if (newConf->links[i].bandwidth == 0)
 2511                         return (0);
 2512                 if (newConf->links[i].bandwidth > NG_PPP_MAX_BANDWIDTH)
 2513                         return (0);
 2514                 if (newConf->links[i].latency > NG_PPP_MAX_LATENCY)
 2515                         return (0);
 2516         }
 2517 
 2518         /* Check bundle parameters */
 2519         if (newConf->bund.enableMultilink && newConf->bund.mrru < MP_MIN_MRRU)
 2520                 return (0);
 2521 
 2522         /* Disallow changes to multi-link configuration while MP is active */
 2523         if (priv->numActiveLinks > 0 && newNumLinksActive > 0) {
 2524                 if (!priv->conf.enableMultilink
 2525                                 != !newConf->bund.enableMultilink
 2526                     || !priv->conf.xmitShortSeq != !newConf->bund.xmitShortSeq
 2527                     || !priv->conf.recvShortSeq != !newConf->bund.recvShortSeq)
 2528                         return (0);
 2529         }
 2530 
 2531         /* At most one link can be active unless multi-link is enabled */
 2532         if (!newConf->bund.enableMultilink && newNumLinksActive > 1)
 2533                 return (0);
 2534 
 2535         /* Configuration change would be valid */
 2536         return (1);
 2537 }
 2538 
 2539 /*
 2540  * Free all entries in the fragment queue
 2541  */
 2542 static void
 2543 ng_ppp_frag_reset(node_p node)
 2544 {
 2545         const priv_p priv = NG_NODE_PRIVATE(node);
 2546         struct ng_ppp_frag *qent, *qnext;
 2547 
 2548         for (qent = TAILQ_FIRST(&priv->frags); qent; qent = qnext) {
 2549                 qnext = TAILQ_NEXT(qent, f_qent);
 2550                 NG_FREE_M(qent->data);
 2551                 FREE(qent, M_NETGRAPH_PPP);
 2552         }
 2553         TAILQ_INIT(&priv->frags);
 2554         priv->qlen = 0;
 2555 }
 2556 
 2557 /*
 2558  * Start fragment queue timer
 2559  */
 2560 static void
 2561 ng_ppp_start_frag_timer(node_p node)
 2562 {
 2563         const priv_p priv = NG_NODE_PRIVATE(node);
 2564 
 2565         if (!(callout_pending(&priv->fragTimer)))
 2566                 ng_callout(&priv->fragTimer, node, NULL, MP_FRAGTIMER_INTERVAL,
 2567                     ng_ppp_frag_timeout, NULL, 0);
 2568 }
 2569 
 2570 /*
 2571  * Stop fragment queue timer
 2572  */
 2573 static void
 2574 ng_ppp_stop_frag_timer(node_p node)
 2575 {
 2576         const priv_p priv = NG_NODE_PRIVATE(node);
 2577 
 2578         if (callout_pending(&priv->fragTimer))
 2579                 ng_uncallout(&priv->fragTimer, node);
 2580 }

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