sys/netgraph/frame_relay/ng_frame_relay.c

   1
   2 /*
   3  * ng_frame_relay.c
   4  *
   5  * Copyright (c) 1996-1999 Whistle Communications, Inc.
   6  * All rights reserved.
   7  *
   8  * Subject to the following obligations and disclaimer of warranty, use and
   9  * redistribution of this software, in source or object code forms, with or
  10  * without modifications are expressly permitted by Whistle Communications;
  11  * provided, however, that:
  12  * 1. Any and all reproductions of the source or object code must include the
  13  *    copyright notice above and the following disclaimer of warranties; and
  14  * 2. No rights are granted, in any manner or form, to use Whistle
  15  *    Communications, Inc. trademarks, including the mark "WHISTLE
  16  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  17  *    such appears in the above copyright notice or in the software.
  18  *
  19  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  20  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  21  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  22  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  23  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  24  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  25  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  26  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  27  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  28  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  29  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  30  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  31  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  35  * OF SUCH DAMAGE.
  36  *
  37  * Author: Julian Elisher <julian@freebsd.org>
  38  *
  39  * $FreeBSD: src/sys/netgraph/ng_frame_relay.c,v 1.9.2.2 2000/10/24 18:36:45 julian Exp $
  40  * $DragonFly: src/sys/netgraph/frame_relay/ng_frame_relay.c,v 1.6 2008/01/05 14:02:39 swildner 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 #include <machine/clock.h>
  62
  63 #include <netgraph/ng_message.h>
  64 #include <netgraph/netgraph.h>
  65 #include "ng_frame_relay.h"
  66
  67 /*
  68  * Line info, and status per channel.
  69  */
  70 struct ctxinfo {                /* one per active hook */
  71         u_int   flags;
  72 #define CHAN_VALID      0x01    /* assigned to a channel */
  73 #define CHAN_ACTIVE     0x02    /* bottom level active */
  74         int     dlci;           /* the dlci assigned to this context */
  75         hook_p  hook;           /* if there's a hook assigned.. */
  76 };
  77
  78 #define MAX_CT 16               /* # of dlci's active at a time (POWER OF 2!) */
  79 struct frmrel_softc {
  80         int     unit;           /* which card are we? */
  81         int     datahooks;      /* number of data hooks attached */
  82         node_p  node;           /* netgraph node */
  83         int     addrlen;        /* address header length */
  84         int     flags;          /* state */
  85         int     mtu;            /* guess */
  86         u_char  remote_seq;     /* sequence number the remote sent */
  87         u_char  local_seq;      /* sequence number the remote rcvd */
  88         u_short ALT[1024];      /* map DLCIs to CTX */
  89 #define CTX_VALID       0x8000          /* this bit means it's a valid CTX */
  90 #define CTX_VALUE       (MAX_CT - 1)    /* mask for context part */
  91         struct  ctxinfo channel[MAX_CT];
  92         struct  ctxinfo downstream;
  93 };
  94 typedef struct frmrel_softc *sc_p;
  95
  96 #define BYTEX_EA        0x01    /* End Address. Always 0 on byte1 */
  97 #define BYTE1_C_R       0x02
  98 #define BYTE2_FECN      0x08    /* forwards congestion notification */
  99 #define BYTE2_BECN      0x04    /* Backward congestion notification */
 100 #define BYTE2_DE        0x02    /* Discard elligability */
 101 #define LASTBYTE_D_C    0x02    /* last byte is dl_core or dlci info */
 102
 103 /* Used to do headers */
 104 static struct segment {
 105         u_char  mask;
 106         u_char  shift;
 107         u_char  width;
 108 } makeup[] = {
 109         { 0xfc, 2, 6 },
 110         { 0xf0, 4, 4 },
 111         { 0xfe, 1, 7 },
 112         { 0xfc, 2, 6 }
 113 };
 114
 115 #define SHIFTIN(segment, byte, dlci)                                         \
 116         {                                                                    \
 117                 (dlci) <<= (segment)->width;                                 \
 118                 (dlci) |=                                                    \
 119                         (((byte) & (segment)->mask) >> (segment)->shift);    \
 120         }
 121
 122 #define SHIFTOUT(segment, byte, dlci)                                        \
 123         {                                                                    \
 124                 (byte) |= (((dlci) << (segment)->shift) & (segment)->mask);  \
 125                 (dlci) >>= (segment)->width;                                 \
 126         }
 127
 128 /* Netgraph methods */
 129 static ng_constructor_t ngfrm_constructor;
 130 static ng_shutdown_t    ngfrm_rmnode;
 131 static ng_newhook_t     ngfrm_newhook;
 132 static ng_rcvdata_t     ngfrm_rcvdata;
 133 static ng_disconnect_t  ngfrm_disconnect;
 134
 135 /* Other internal functions */
 136 static int ngfrm_decode(node_p node, struct mbuf * m, meta_p meta);
 137 static int ngfrm_addrlen(char *hdr);
 138 static int ngfrm_allocate_CTX(sc_p sc, int dlci);
 139
 140 /* Netgraph type */
 141 static struct ng_type typestruct = {
 142         NG_VERSION,
 143         NG_FRAMERELAY_NODE_TYPE,
 144         NULL,
 145         ngfrm_constructor,
 146         NULL,
 147         ngfrm_rmnode,
 148         ngfrm_newhook,
 149         NULL,
 150         NULL,
 151         ngfrm_rcvdata,
 152         ngfrm_rcvdata,
 153         ngfrm_disconnect,
 154         NULL
 155 };
 156 NETGRAPH_INIT(framerelay, &typestruct);
 157
 158 /*
 159  * Given a DLCI, return the index of the  context table entry for it,
 160  * Allocating a new one if needs be, or -1 if none available.
 161  */
 162 static int
 163 ngfrm_allocate_CTX(sc_p sc, int dlci)
 164 {
 165         u_int   ctxnum = -1;    /* what ctx number we are using */
 166         volatile struct ctxinfo *CTXp = NULL;
 167
 168         /* Sanity check the dlci value */
 169         if (dlci > 1023)
 170                 return (-1);
 171
 172         /* Check to see if we already have an entry for this DLCI */
 173         if (sc->ALT[dlci]) {
 174                 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) {
 175                         CTXp = sc->channel + ctxnum;
 176                 } else {
 177                         ctxnum = -1;
 178                         sc->ALT[dlci] = 0;      /* paranoid but... */
 179                 }
 180         }
 181
 182         /*
 183          * If the index has no valid entry yet, then we need to allocate a
 184          * CTX number to it
 185          */
 186         if (CTXp == NULL) {
 187                 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) {
 188                         /*
 189                          * If the VALID flag is empty it is unused
 190                          */
 191                         if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) {
 192                                 bzero(sc->channel + ctxnum,
 193                                       sizeof(struct ctxinfo));
 194                                 CTXp = sc->channel + ctxnum;
 195                                 sc->ALT[dlci] = ctxnum | CTX_VALID;
 196                                 sc->channel[ctxnum].dlci = dlci;
 197                                 sc->channel[ctxnum].flags = CHAN_VALID;
 198                                 break;
 199                         }
 200                 }
 201         }
 202
 203         /*
 204          * If we still don't have a CTX pointer, then we never found a free
 205          * spot so give up now..
 206          */
 207         if (!CTXp) {
 208                 log(LOG_ERR, "No CTX available for dlci %d\n", dlci);
 209                 return (-1);
 210         }
 211         return (ctxnum);
 212 }
 213
 214 /*
 215  * Node constructor
 216  */
 217 static int
 218 ngfrm_constructor(node_p *nodep)
 219 {
 220         sc_p sc;
 221         int error = 0;
 222
 223         MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_NOWAIT | M_ZERO);
 224         if (!sc)
 225                 return (ENOMEM);
 226         if ((error = ng_make_node_common(&typestruct, nodep))) {
 227                 FREE(sc, M_NETGRAPH);
 228                 return (error);
 229         }
 230         sc->addrlen = 2;        /* default */
 231
 232         /* Link the node and our private info */
 233         (*nodep)->private = sc;
 234         sc->node = *nodep;
 235         return (0);
 236 }
 237
 238 /*
 239  * Add a new hook
 240  *
 241  * We allow hooks called "debug", "downstream" and dlci[0-1023]
 242  * The hook's private info points to our stash of info about that
 243  * channel. A NULL pointer is debug and a DLCI of -1 means downstream.
 244  */
 245 static int
 246 ngfrm_newhook(node_p node, hook_p hook, const char *name)
 247 {
 248         const sc_p sc = node->private;
 249         const char *cp;
 250         char *eptr;
 251         int dlci = 0;
 252         int ctxnum;
 253
 254         /* Check if it's our friend the control hook */
 255         if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) {
 256                 hook->private = NULL;   /* paranoid */
 257                 return (0);
 258         }
 259
 260         /*
 261          * All other hooks either start with 'dlci' and have a decimal
 262          * trailing channel number up to 4 digits, or are the downstream
 263          * hook.
 264          */
 265         if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI,
 266             strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) {
 267
 268                 /* It must be the downstream connection */
 269                 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0)
 270                         return EINVAL;
 271
 272                 /* Make sure we haven't already got one (paranoid) */
 273                 if (sc->downstream.hook)
 274                         return (EADDRINUSE);
 275
 276                 /* OK add it */
 277                 hook->private = &sc->downstream;
 278                 sc->downstream.hook = hook;
 279                 sc->downstream.dlci = -1;
 280                 sc->downstream.flags |= CHAN_ACTIVE;
 281                 sc->datahooks++;
 282                 return (0);
 283         }
 284
 285         /* Must be a dlci hook at this point */
 286         cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI);
 287         if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 288                 return (EINVAL);
 289         dlci = (int)strtoul(cp, &eptr, 10);
 290         if (*eptr != '\0' || dlci < 0 || dlci > 1023)
 291                 return (EINVAL);
 292
 293         /*
 294          * We have a dlci, now either find it, or allocate it. It's possible
 295          * that we might have seen packets for it already and made an entry
 296          * for it.
 297          */
 298         ctxnum = ngfrm_allocate_CTX(sc, dlci);
 299         if (ctxnum == -1)
 300                 return (ENOBUFS);
 301
 302         /*
 303          * Be paranoid: if it's got a hook already, that dlci is in use .
 304          * Generic code can not catch all the synonyms (e.g. dlci016 vs
 305          * dlci16)
 306          */
 307         if (sc->channel[ctxnum].hook != NULL)
 308                 return (EADDRINUSE);
 309
 310         /*
 311          * Put our hooks into it (pun not intended)
 312          */
 313         sc->channel[ctxnum].flags |= CHAN_ACTIVE;
 314         hook->private = sc->channel + ctxnum;
 315         sc->channel[ctxnum].hook = hook;
 316         sc->datahooks++;
 317         return (0);
 318 }
 319
 320 /*
 321  * Count up the size of the address header if we don't already know
 322  */
 323 int
 324 ngfrm_addrlen(char *hdr)
 325 {
 326         if (hdr[0] & BYTEX_EA)
 327                 return 0;
 328         if (hdr[1] & BYTEX_EA)
 329                 return 2;
 330         if (hdr[2] & BYTEX_EA)
 331                 return 3;
 332         if (hdr[3] & BYTEX_EA)
 333                 return 4;
 334         return 0;
 335 }
 336
 337 /*
 338  * Receive data packet
 339  */
 340 static int
 341 ngfrm_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
 342 {
 343         struct  ctxinfo *const ctxp = hook->private;
 344         int     error = 0;
 345         int     dlci;
 346         sc_p    sc;
 347         int     alen;
 348         char   *data;
 349
 350         /* Data doesn't come in from just anywhere (e.g debug hook) */
 351         if (ctxp == NULL) {
 352                 error = ENETDOWN;
 353                 goto bad;
 354         }
 355
 356         /* If coming from downstream, decode it to a channel */
 357         dlci = ctxp->dlci;
 358         if (dlci == -1)
 359                 return (ngfrm_decode(hook->node, m, meta));
 360
 361         /* Derive the softc we will need */
 362         sc = hook->node->private;
 363
 364         /* If there is no live channel, throw it away */
 365         if ((sc->downstream.hook == NULL)
 366             || ((ctxp->flags & CHAN_ACTIVE) == 0)) {
 367                 error = ENETDOWN;
 368                 goto bad;
 369         }
 370
 371         /* Store the DLCI on the front of the packet */
 372         alen = sc->addrlen;
 373         if (alen == 0)
 374                 alen = 2;       /* default value for transmit */
 375         M_PREPEND(m, alen, MB_DONTWAIT);
 376         if (m == NULL) {
 377                 error = ENOBUFS;
 378                 goto bad;
 379         }
 380         data = mtod(m, char *);
 381
 382         /*
 383          * Shift the lowest bits into the address field untill we are done.
 384          * First byte is MSBits of addr so work backwards.
 385          */
 386         switch (alen) {
 387         case 2:
 388                 data[0] = data[1] = '\0';
 389                 SHIFTOUT(makeup + 1, data[1], dlci);
 390                 SHIFTOUT(makeup + 0, data[0], dlci);
 391                 data[1] |= BYTEX_EA;
 392                 break;
 393         case 3:
 394                 data[0] = data[1] = data[2] = '\0';
 395                 SHIFTOUT(makeup + 3, data[2], dlci);    /* 3 and 2 is correct */
 396                 SHIFTOUT(makeup + 1, data[1], dlci);
 397                 SHIFTOUT(makeup + 0, data[0], dlci);
 398                 data[2] |= BYTEX_EA;
 399                 break;
 400         case 4:
 401                 data[0] = data[1] = data[2] = data[3] = '\0';
 402                 SHIFTOUT(makeup + 3, data[3], dlci);
 403                 SHIFTOUT(makeup + 2, data[2], dlci);
 404                 SHIFTOUT(makeup + 1, data[1], dlci);
 405                 SHIFTOUT(makeup + 0, data[0], dlci);
 406                 data[3] |= BYTEX_EA;
 407                 break;
 408         default:
 409                 panic(__func__);
 410         }
 411
 412         /* Send it */
 413         NG_SEND_DATA(error, sc->downstream.hook, m, meta);
 414         return (error);
 415
 416 bad:
 417         NG_FREE_DATA(m, meta);
 418         return (error);
 419 }
 420
 421 /*
 422  * Decode an incoming frame coming from the switch
 423  */
 424 static int
 425 ngfrm_decode(node_p node, struct mbuf *m, meta_p meta)
 426 {
 427         const sc_p  sc = node->private;
 428         char       *data;
 429         int         alen;
 430         u_int       dlci = 0;
 431         int         error = 0;
 432         int         ctxnum;
 433
 434         if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
 435                 error = ENOBUFS;
 436                 goto out;
 437         }
 438         data = mtod(m, char *);
 439         if ((alen = sc->addrlen) == 0) {
 440                 sc->addrlen = alen = ngfrm_addrlen(data);
 441         }
 442         switch (alen) {
 443         case 2:
 444                 SHIFTIN(makeup + 0, data[0], dlci);
 445                 SHIFTIN(makeup + 1, data[1], dlci);
 446                 break;
 447         case 3:
 448                 SHIFTIN(makeup + 0, data[0], dlci);
 449                 SHIFTIN(makeup + 1, data[1], dlci);
 450                 SHIFTIN(makeup + 3, data[2], dlci);     /* 3 and 2 is correct */
 451                 break;
 452         case 4:
 453                 SHIFTIN(makeup + 0, data[0], dlci);
 454                 SHIFTIN(makeup + 1, data[1], dlci);
 455                 SHIFTIN(makeup + 2, data[2], dlci);
 456                 SHIFTIN(makeup + 3, data[3], dlci);
 457                 break;
 458         default:
 459                 error = EINVAL;
 460                 goto out;
 461         }
 462
 463         if (dlci > 1023) {
 464                 error = EINVAL;
 465                 goto out;
 466         }
 467         ctxnum = sc->ALT[dlci];
 468         if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) {
 469                 /* Send it */
 470                 m_adj(m, alen);
 471                 NG_SEND_DATA(error, sc->channel[ctxnum].hook, m, meta);
 472                 return (error);
 473         } else {
 474                 error = ENETDOWN;
 475         }
 476 out:
 477         NG_FREE_DATA(m, meta);
 478         return (error);
 479 }
 480
 481 /*
 482  * Shutdown node
 483  */
 484 static int
 485 ngfrm_rmnode(node_p node)
 486 {
 487         const sc_p sc = node->private;
 488
 489         node->flags |= NG_INVALID;
 490         ng_cutlinks(node);
 491         ng_unname(node);
 492         node->private = NULL;
 493         FREE(sc, M_NETGRAPH);
 494         ng_unref(node);
 495         return (0);
 496 }
 497
 498 /*
 499  * Hook disconnection
 500  *
 501  * Invalidate the private data associated with this dlci.
 502  * For this type, removal of the last link resets tries to destroy the node.
 503  */
 504 static int
 505 ngfrm_disconnect(hook_p hook)
 506 {
 507         const sc_p sc = hook->node->private;
 508         struct ctxinfo *const cp = hook->private;
 509         int dlci;
 510
 511         /* If it's a regular dlci hook, then free resources etc.. */
 512         if (cp != NULL) {
 513                 cp->hook = NULL;
 514                 dlci = cp->dlci;
 515                 if (dlci != -1)
 516                         sc->ALT[dlci] = 0;
 517                 cp->flags = 0;
 518                 sc->datahooks--;
 519         }
 520         if (hook->node->numhooks == 0)
 521                 ng_rmnode(hook->node);
 522         return (0);
 523 }