sys/netgraph7/frame_relay/ng_frame_relay.c

   1 /*
   2  * ng_frame_relay.c
   3  */
   4
   5 /*-
   6  * Copyright (c) 1996-1999 Whistle Communications, Inc.
   7  * All rights reserved.
   8  *
   9  * Subject to the following obligations and disclaimer of warranty, use and
  10  * redistribution of this software, in source or object code forms, with or
  11  * without modifications are expressly permitted by Whistle Communications;
  12  * provided, however, that:
  13  * 1. Any and all reproductions of the source or object code must include the
  14  *    copyright notice above and the following disclaimer of warranties; and
  15  * 2. No rights are granted, in any manner or form, to use Whistle
  16  *    Communications, Inc. trademarks, including the mark "WHISTLE
  17  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  18  *    such appears in the above copyright notice or in the software.
  19  *
  20  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  21  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  22  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  23  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  25  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  26  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  27  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  28  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  35  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  36  * OF SUCH DAMAGE.
  37  *
  38  * Author: Julian Elischer <julian@freebsd.org>
  39  *
  40  * $FreeBSD: src/sys/netgraph/ng_frame_relay.c,v 1.25 2006/01/14 21:49:31 glebius Exp $
  41  * $Whistle: ng_frame_relay.c,v 1.20 1999/11/01 09:24:51 julian Exp $
  42  */
  43
  44 /*
  45  * This node implements the frame relay protocol, not including
  46  * the LMI line management. This means basically keeping track
  47  * of which DLCI's are active, doing frame (de)multiplexing, etc.
  48  *
  49  * It has a 'downstream' hook that goes to the line, and a
  50  * hook for each DLCI (eg, 'dlci16').
  51  */
  52
  53 #include <sys/param.h>
  54 #include <sys/systm.h>
  55 #include <sys/kernel.h>
  56 #include <sys/errno.h>
  57 #include <sys/malloc.h>
  58 #include <sys/mbuf.h>
  59 #include <sys/syslog.h>
  60 #include <sys/ctype.h>
  61
  62 #include <netgraph7/ng_message.h>
  63 #include <netgraph7/netgraph.h>
  64 #include "ng_frame_relay.h"
  65
  66 /*
  67  * Line info, and status per channel.
  68  */
  69 struct ctxinfo {                /* one per active hook */
  70         u_int   flags;
  71 #define CHAN_VALID      0x01    /* assigned to a channel */
  72 #define CHAN_ACTIVE     0x02    /* bottom level active */
  73         int     dlci;           /* the dlci assigned to this context */
  74         hook_p  hook;           /* if there's a hook assigned.. */
  75 };
  76
  77 #define MAX_CT 16               /* # of dlci's active at a time (POWER OF 2!) */
  78 struct frmrel_softc {
  79         int     unit;           /* which card are we? */
  80         int     datahooks;      /* number of data hooks attached */
  81         node_p  node;           /* netgraph node */
  82         int     addrlen;        /* address header length */
  83         int     flags;          /* state */
  84         int     mtu;            /* guess */
  85         u_char  remote_seq;     /* sequence number the remote sent */
  86         u_char  local_seq;      /* sequence number the remote rcvd */
  87         u_short ALT[1024];      /* map DLCIs to CTX */
  88 #define CTX_VALID       0x8000          /* this bit means it's a valid CTX */
  89 #define CTX_VALUE       (MAX_CT - 1)    /* mask for context part */
  90         struct  ctxinfo channel[MAX_CT];
  91         struct  ctxinfo downstream;
  92 };
  93 typedef struct frmrel_softc *sc_p;
  94
  95 #define BYTEX_EA        0x01    /* End Address. Always 0 on byte1 */
  96 #define BYTE1_C_R       0x02
  97 #define BYTE2_FECN      0x08    /* forwards congestion notification */
  98 #define BYTE2_BECN      0x04    /* Backward congestion notification */
  99 #define BYTE2_DE        0x02    /* Discard elligability */
 100 #define LASTBYTE_D_C    0x02    /* last byte is dl_core or dlci info */
 101
 102 /* Used to do headers */
 103 static const struct segment {
 104         u_char  mask;
 105         u_char  shift;
 106         u_char  width;
 107 } makeup[] = {
 108         { 0xfc, 2, 6 },
 109         { 0xf0, 4, 4 },
 110         { 0xfe, 1, 7 },
 111         { 0xfc, 2, 6 }
 112 };
 113
 114 #define SHIFTIN(segment, byte, dlci)                                         \
 115         {                                                                    \
 116                 (dlci) <<= (segment)->width;                                 \
 117                 (dlci) |=                                                    \
 118                         (((byte) & (segment)->mask) >> (segment)->shift);    \
 119         }
 120
 121 #define SHIFTOUT(segment, byte, dlci)                                        \
 122         {                                                                    \
 123                 (byte) |= (((dlci) << (segment)->shift) & (segment)->mask);  \
 124                 (dlci) >>= (segment)->width;                                 \
 125         }
 126
 127 /* Netgraph methods */
 128 static ng_constructor_t ngfrm_constructor;
 129 static ng_shutdown_t    ngfrm_shutdown;
 130 static ng_newhook_t     ngfrm_newhook;
 131 static ng_rcvdata_t     ngfrm_rcvdata;
 132 static ng_disconnect_t  ngfrm_disconnect;
 133
 134 /* Other internal functions */
 135 static int ngfrm_decode(node_p node, item_p item);
 136 static int ngfrm_addrlen(char *hdr);
 137 static int ngfrm_allocate_CTX(sc_p sc, int dlci);
 138
 139 /* Netgraph type */
 140 static struct ng_type typestruct = {
 141         .version =      NG_ABI_VERSION,
 142         .name =         NG_FRAMERELAY_NODE_TYPE,
 143         .constructor =  ngfrm_constructor,
 144         .shutdown =     ngfrm_shutdown,
 145         .newhook =      ngfrm_newhook,
 146         .rcvdata =      ngfrm_rcvdata,
 147         .disconnect =   ngfrm_disconnect,
 148 };
 149 NETGRAPH_INIT(framerelay, &typestruct);
 150
 151 /*
 152  * Given a DLCI, return the index of the  context table entry for it,
 153  * Allocating a new one if needs be, or -1 if none available.
 154  */
 155 static int
 156 ngfrm_allocate_CTX(sc_p sc, int dlci)
 157 {
 158         u_int   ctxnum = -1;    /* what ctx number we are using */
 159         volatile struct ctxinfo *CTXp = NULL;
 160
 161         /* Sanity check the dlci value */
 162         if (dlci > 1023)
 163                 return (-1);
 164
 165         /* Check to see if we already have an entry for this DLCI */
 166         if (sc->ALT[dlci]) {
 167                 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) {
 168                         CTXp = sc->channel + ctxnum;
 169                 } else {
 170                         ctxnum = -1;
 171                         sc->ALT[dlci] = 0;      /* paranoid but... */
 172                 }
 173         }
 174
 175         /*
 176          * If the index has no valid entry yet, then we need to allocate a
 177          * CTX number to it
 178          */
 179         if (CTXp == NULL) {
 180                 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) {
 181                         /*
 182                          * If the VALID flag is empty it is unused
 183                          */
 184                         if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) {
 185                                 bzero(sc->channel + ctxnum,
 186                                       sizeof(struct ctxinfo));
 187                                 CTXp = sc->channel + ctxnum;
 188                                 sc->ALT[dlci] = ctxnum | CTX_VALID;
 189                                 sc->channel[ctxnum].dlci = dlci;
 190                                 sc->channel[ctxnum].flags = CHAN_VALID;
 191                                 break;
 192                         }
 193                 }
 194         }
 195
 196         /*
 197          * If we still don't have a CTX pointer, then we never found a free
 198          * spot so give up now..
 199          */
 200         if (!CTXp) {
 201                 log(LOG_ERR, "No CTX available for dlci %d\n", dlci);
 202                 return (-1);
 203         }
 204         return (ctxnum);
 205 }
 206
 207 /*
 208  * Node constructor
 209  */
 210 static int
 211 ngfrm_constructor(node_p node)
 212 {
 213         sc_p sc;
 214
 215         sc = kmalloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_NULLOK | M_ZERO);
 216         if (!sc)
 217                 return (ENOMEM);
 218         sc->addrlen = 2;        /* default */
 219
 220         /* Link the node and our private info */
 221         NG_NODE_SET_PRIVATE(node, sc);
 222         sc->node = node;
 223         return (0);
 224 }
 225
 226 /*
 227  * Add a new hook
 228  *
 229  * We allow hooks called "debug", "downstream" and dlci[0-1023]
 230  * The hook's private info points to our stash of info about that
 231  * channel. A NULL pointer is debug and a DLCI of -1 means downstream.
 232  */
 233 static int
 234 ngfrm_newhook(node_p node, hook_p hook, const char *name)
 235 {
 236         const sc_p sc = NG_NODE_PRIVATE(node);
 237         const char *cp;
 238         char *eptr;
 239         int dlci = 0;
 240         int ctxnum;
 241
 242         /* Check if it's our friend the control hook */
 243         if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) {
 244                 NG_HOOK_SET_PRIVATE(hook, NULL);        /* paranoid */
 245                 return (0);
 246         }
 247
 248         /*
 249          * All other hooks either start with 'dlci' and have a decimal
 250          * trailing channel number up to 4 digits, or are the downstream
 251          * hook.
 252          */
 253         if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI,
 254             strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) {
 255
 256                 /* It must be the downstream connection */
 257                 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0)
 258                         return EINVAL;
 259
 260                 /* Make sure we haven't already got one (paranoid) */
 261                 if (sc->downstream.hook)
 262                         return (EADDRINUSE);
 263
 264                 /* OK add it */
 265                 NG_HOOK_SET_PRIVATE(hook, &sc->downstream);
 266                 sc->downstream.hook = hook;
 267                 sc->downstream.dlci = -1;
 268                 sc->downstream.flags |= CHAN_ACTIVE;
 269                 sc->datahooks++;
 270                 return (0);
 271         }
 272
 273         /* Must be a dlci hook at this point */
 274         cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI);
 275         if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 276                 return (EINVAL);
 277         dlci = (int)strtoul(cp, &eptr, 10);
 278         if (*eptr != '\0' || dlci < 0 || dlci > 1023)
 279                 return (EINVAL);
 280
 281         /*
 282          * We have a dlci, now either find it, or allocate it. It's possible
 283          * that we might have seen packets for it already and made an entry
 284          * for it.
 285          */
 286         ctxnum = ngfrm_allocate_CTX(sc, dlci);
 287         if (ctxnum == -1)
 288                 return (ENOBUFS);
 289
 290         /*
 291          * Be paranoid: if it's got a hook already, that dlci is in use .
 292          * Generic code can not catch all the synonyms (e.g. dlci016 vs
 293          * dlci16)
 294          */
 295         if (sc->channel[ctxnum].hook != NULL)
 296                 return (EADDRINUSE);
 297
 298         /*
 299          * Put our hooks into it (pun not intended)
 300          */
 301         sc->channel[ctxnum].flags |= CHAN_ACTIVE;
 302         NG_HOOK_SET_PRIVATE(hook, sc->channel + ctxnum);
 303         sc->channel[ctxnum].hook = hook;
 304         sc->datahooks++;
 305         return (0);
 306 }
 307
 308 /*
 309  * Count up the size of the address header if we don't already know
 310  */
 311 int
 312 ngfrm_addrlen(char *hdr)
 313 {
 314         if (hdr[0] & BYTEX_EA)
 315                 return 0;
 316         if (hdr[1] & BYTEX_EA)
 317                 return 2;
 318         if (hdr[2] & BYTEX_EA)
 319                 return 3;
 320         if (hdr[3] & BYTEX_EA)
 321                 return 4;
 322         return 0;
 323 }
 324
 325 /*
 326  * Receive data packet
 327  */
 328 static int
 329 ngfrm_rcvdata(hook_p hook, item_p item)
 330 {
 331         struct  ctxinfo *const ctxp = NG_HOOK_PRIVATE(hook);
 332         struct  mbuf *m = NULL;
 333         int     error = 0;
 334         int     dlci;
 335         sc_p    sc;
 336         int     alen;
 337         char   *data;
 338
 339         /* Data doesn't come in from just anywhere (e.g debug hook) */
 340         if (ctxp == NULL) {
 341                 error = ENETDOWN;
 342                 goto bad;
 343         }
 344
 345         /* If coming from downstream, decode it to a channel */
 346         dlci = ctxp->dlci;
 347         if (dlci == -1)
 348                 return (ngfrm_decode(NG_HOOK_NODE(hook), item));
 349
 350         NGI_GET_M(item, m);
 351         /* Derive the softc we will need */
 352         sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 353
 354         /* If there is no live channel, throw it away */
 355         if ((sc->downstream.hook == NULL)
 356             || ((ctxp->flags & CHAN_ACTIVE) == 0)) {
 357                 error = ENETDOWN;
 358                 goto bad;
 359         }
 360
 361         /* Store the DLCI on the front of the packet */
 362         alen = sc->addrlen;
 363         if (alen == 0)
 364                 alen = 2;       /* default value for transmit */
 365         M_PREPEND(m, alen, M_NOWAIT);
 366         if (m == NULL) {
 367                 error = ENOBUFS;
 368                 goto bad;
 369         }
 370         data = mtod(m, char *);
 371
 372         /*
 373          * Shift the lowest bits into the address field untill we are done.
 374          * First byte is MSBits of addr so work backwards.
 375          */
 376         switch (alen) {
 377         case 2:
 378                 data[0] = data[1] = '\0';
 379                 SHIFTOUT(makeup + 1, data[1], dlci);
 380                 SHIFTOUT(makeup + 0, data[0], dlci);
 381                 data[1] |= BYTEX_EA;
 382                 break;
 383         case 3:
 384                 data[0] = data[1] = data[2] = '\0';
 385                 SHIFTOUT(makeup + 3, data[2], dlci);    /* 3 and 2 is correct */
 386                 SHIFTOUT(makeup + 1, data[1], dlci);
 387                 SHIFTOUT(makeup + 0, data[0], dlci);
 388                 data[2] |= BYTEX_EA;
 389                 break;
 390         case 4:
 391                 data[0] = data[1] = data[2] = data[3] = '\0';
 392                 SHIFTOUT(makeup + 3, data[3], dlci);
 393                 SHIFTOUT(makeup + 2, data[2], dlci);
 394                 SHIFTOUT(makeup + 1, data[1], dlci);
 395                 SHIFTOUT(makeup + 0, data[0], dlci);
 396                 data[3] |= BYTEX_EA;
 397                 break;
 398         default:
 399                 panic(__func__);
 400         }
 401
 402         /* Send it */
 403         NG_FWD_NEW_DATA(error, item, sc->downstream.hook, m);
 404         return (error);
 405
 406 bad:
 407         NG_FREE_ITEM(item);
 408         NG_FREE_M(m);
 409         return (error);
 410 }
 411
 412 /*
 413  * Decode an incoming frame coming from the switch
 414  */
 415 static int
 416 ngfrm_decode(node_p node, item_p item)
 417 {
 418         const sc_p  sc = NG_NODE_PRIVATE(node);
 419         char       *data;
 420         int         alen;
 421         u_int       dlci = 0;
 422         int         error = 0;
 423         int         ctxnum;
 424         struct mbuf *m;
 425
 426         NGI_GET_M(item, m);
 427         if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
 428                 error = ENOBUFS;
 429                 goto out;
 430         }
 431         data = mtod(m, char *);
 432         if ((alen = sc->addrlen) == 0) {
 433                 sc->addrlen = alen = ngfrm_addrlen(data);
 434         }
 435         switch (alen) {
 436         case 2:
 437                 SHIFTIN(makeup + 0, data[0], dlci);
 438                 SHIFTIN(makeup + 1, data[1], dlci);
 439                 break;
 440         case 3:
 441                 SHIFTIN(makeup + 0, data[0], dlci);
 442                 SHIFTIN(makeup + 1, data[1], dlci);
 443                 SHIFTIN(makeup + 3, data[2], dlci);     /* 3 and 2 is correct */
 444                 break;
 445         case 4:
 446                 SHIFTIN(makeup + 0, data[0], dlci);
 447                 SHIFTIN(makeup + 1, data[1], dlci);
 448                 SHIFTIN(makeup + 2, data[2], dlci);
 449                 SHIFTIN(makeup + 3, data[3], dlci);
 450                 break;
 451         default:
 452                 error = EINVAL;
 453                 goto out;
 454         }
 455
 456         if (dlci > 1023) {
 457                 error = EINVAL;
 458                 goto out;
 459         }
 460         ctxnum = sc->ALT[dlci];
 461         if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) {
 462                 /* Send it */
 463                 m_adj(m, alen);
 464                 NG_FWD_NEW_DATA(error, item, sc->channel[ctxnum].hook, m);
 465                 return (error);
 466         } else {
 467                 error = ENETDOWN;
 468         }
 469 out:
 470         NG_FREE_ITEM(item);
 471         NG_FREE_M(m);
 472         return (error);
 473 }
 474
 475 /*
 476  * Shutdown node
 477  */
 478 static int
 479 ngfrm_shutdown(node_p node)
 480 {
 481         const sc_p sc = NG_NODE_PRIVATE(node);
 482
 483         NG_NODE_SET_PRIVATE(node, NULL);
 484         kfree(sc, M_NETGRAPH);
 485         NG_NODE_UNREF(node);
 486         return (0);
 487 }
 488
 489 /*
 490  * Hook disconnection
 491  *
 492  * Invalidate the private data associated with this dlci.
 493  * For this type, removal of the last link resets tries to destroy the node.
 494  */
 495 static int
 496 ngfrm_disconnect(hook_p hook)
 497 {
 498         const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 499         struct ctxinfo *const cp = NG_HOOK_PRIVATE(hook);
 500         int dlci;
 501
 502         /* If it's a regular dlci hook, then free resources etc.. */
 503         if (cp != NULL) {
 504                 cp->hook = NULL;
 505                 dlci = cp->dlci;
 506                 if (dlci != -1)
 507                         sc->ALT[dlci] = 0;
 508                 cp->flags = 0;
 509                 sc->datahooks--;
 510         }
 511         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 512         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
 513                 ng_rmnode_self(NG_HOOK_NODE(hook));
 514         return (0);
 515 }