sys/netgraph7/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  * $DragonFly: src/sys/netgraph7/ng_frame_relay.c,v 1.2 2008/06/26 23:05:35 dillon Exp $
  42  * $Whistle: ng_frame_relay.c,v 1.20 1999/11/01 09:24:51 julian Exp $
  43  */
  44
  45 /*
  46  * This node implements the frame relay protocol, not including
  47  * the LMI line management. This means basically keeping track
  48  * of which DLCI's are active, doing frame (de)multiplexing, etc.
  49  *
  50  * It has a 'downstream' hook that goes to the line, and a
  51  * hook for each DLCI (eg, 'dlci16').
  52  */
  53
  54 #include <sys/param.h>
  55 #include <sys/systm.h>
  56 #include <sys/kernel.h>
  57 #include <sys/errno.h>
  58 #include <sys/malloc.h>
  59 #include <sys/mbuf.h>
  60 #include <sys/syslog.h>
  61 #include <sys/ctype.h>
  62
  63 #include "ng_message.h"
  64 #include "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 const 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_shutdown;
 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, item_p item);
 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         .version =      NG_ABI_VERSION,
 143         .name =         NG_FRAMERELAY_NODE_TYPE,
 144         .constructor =  ngfrm_constructor,
 145         .shutdown =     ngfrm_shutdown,
 146         .newhook =      ngfrm_newhook,
 147         .rcvdata =      ngfrm_rcvdata,
 148         .disconnect =   ngfrm_disconnect,
 149 };
 150 NETGRAPH_INIT(framerelay, &typestruct);
 151
 152 /*
 153  * Given a DLCI, return the index of the  context table entry for it,
 154  * Allocating a new one if needs be, or -1 if none available.
 155  */
 156 static int
 157 ngfrm_allocate_CTX(sc_p sc, int dlci)
 158 {
 159         u_int   ctxnum = -1;    /* what ctx number we are using */
 160         volatile struct ctxinfo *CTXp = NULL;
 161
 162         /* Sanity check the dlci value */
 163         if (dlci > 1023)
 164                 return (-1);
 165
 166         /* Check to see if we already have an entry for this DLCI */
 167         if (sc->ALT[dlci]) {
 168                 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) {
 169                         CTXp = sc->channel + ctxnum;
 170                 } else {
 171                         ctxnum = -1;
 172                         sc->ALT[dlci] = 0;      /* paranoid but... */
 173                 }
 174         }
 175
 176         /*
 177          * If the index has no valid entry yet, then we need to allocate a
 178          * CTX number to it
 179          */
 180         if (CTXp == NULL) {
 181                 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) {
 182                         /*
 183                          * If the VALID flag is empty it is unused
 184                          */
 185                         if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) {
 186                                 bzero(sc->channel + ctxnum,
 187                                       sizeof(struct ctxinfo));
 188                                 CTXp = sc->channel + ctxnum;
 189                                 sc->ALT[dlci] = ctxnum | CTX_VALID;
 190                                 sc->channel[ctxnum].dlci = dlci;
 191                                 sc->channel[ctxnum].flags = CHAN_VALID;
 192                                 break;
 193                         }
 194                 }
 195         }
 196
 197         /*
 198          * If we still don't have a CTX pointer, then we never found a free
 199          * spot so give up now..
 200          */
 201         if (!CTXp) {
 202                 log(LOG_ERR, "No CTX available for dlci %d\n", dlci);
 203                 return (-1);
 204         }
 205         return (ctxnum);
 206 }
 207
 208 /*
 209  * Node constructor
 210  */
 211 static int
 212 ngfrm_constructor(node_p node)
 213 {
 214         sc_p sc;
 215
 216         MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK | M_NULLOK | M_ZERO);
 217         if (!sc)
 218                 return (ENOMEM);
 219         sc->addrlen = 2;        /* default */
 220
 221         /* Link the node and our private info */
 222         NG_NODE_SET_PRIVATE(node, sc);
 223         sc->node = node;
 224         return (0);
 225 }
 226
 227 /*
 228  * Add a new hook
 229  *
 230  * We allow hooks called "debug", "downstream" and dlci[0-1023]
 231  * The hook's private info points to our stash of info about that
 232  * channel. A NULL pointer is debug and a DLCI of -1 means downstream.
 233  */
 234 static int
 235 ngfrm_newhook(node_p node, hook_p hook, const char *name)
 236 {
 237         const sc_p sc = NG_NODE_PRIVATE(node);
 238         const char *cp;
 239         char *eptr;
 240         int dlci = 0;
 241         int ctxnum;
 242
 243         /* Check if it's our friend the control hook */
 244         if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) {
 245                 NG_HOOK_SET_PRIVATE(hook, NULL);        /* paranoid */
 246                 return (0);
 247         }
 248
 249         /*
 250          * All other hooks either start with 'dlci' and have a decimal
 251          * trailing channel number up to 4 digits, or are the downstream
 252          * hook.
 253          */
 254         if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI,
 255             strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) {
 256
 257                 /* It must be the downstream connection */
 258                 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0)
 259                         return EINVAL;
 260
 261                 /* Make sure we haven't already got one (paranoid) */
 262                 if (sc->downstream.hook)
 263                         return (EADDRINUSE);
 264
 265                 /* OK add it */
 266                 NG_HOOK_SET_PRIVATE(hook, &sc->downstream);
 267                 sc->downstream.hook = hook;
 268                 sc->downstream.dlci = -1;
 269                 sc->downstream.flags |= CHAN_ACTIVE;
 270                 sc->datahooks++;
 271                 return (0);
 272         }
 273
 274         /* Must be a dlci hook at this point */
 275         cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI);
 276         if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 277                 return (EINVAL);
 278         dlci = (int)strtoul(cp, &eptr, 10);
 279         if (*eptr != '\0' || dlci < 0 || dlci > 1023)
 280                 return (EINVAL);
 281
 282         /*
 283          * We have a dlci, now either find it, or allocate it. It's possible
 284          * that we might have seen packets for it already and made an entry
 285          * for it.
 286          */
 287         ctxnum = ngfrm_allocate_CTX(sc, dlci);
 288         if (ctxnum == -1)
 289                 return (ENOBUFS);
 290
 291         /*
 292          * Be paranoid: if it's got a hook already, that dlci is in use .
 293          * Generic code can not catch all the synonyms (e.g. dlci016 vs
 294          * dlci16)
 295          */
 296         if (sc->channel[ctxnum].hook != NULL)
 297                 return (EADDRINUSE);
 298
 299         /*
 300          * Put our hooks into it (pun not intended)
 301          */
 302         sc->channel[ctxnum].flags |= CHAN_ACTIVE;
 303         NG_HOOK_SET_PRIVATE(hook, sc->channel + ctxnum);
 304         sc->channel[ctxnum].hook = hook;
 305         sc->datahooks++;
 306         return (0);
 307 }
 308
 309 /*
 310  * Count up the size of the address header if we don't already know
 311  */
 312 int
 313 ngfrm_addrlen(char *hdr)
 314 {
 315         if (hdr[0] & BYTEX_EA)
 316                 return 0;
 317         if (hdr[1] & BYTEX_EA)
 318                 return 2;
 319         if (hdr[2] & BYTEX_EA)
 320                 return 3;
 321         if (hdr[3] & BYTEX_EA)
 322                 return 4;
 323         return 0;
 324 }
 325
 326 /*
 327  * Receive data packet
 328  */
 329 static int
 330 ngfrm_rcvdata(hook_p hook, item_p item)
 331 {
 332         struct  ctxinfo *const ctxp = NG_HOOK_PRIVATE(hook);
 333         struct  mbuf *m = NULL;
 334         int     error = 0;
 335         int     dlci;
 336         sc_p    sc;
 337         int     alen;
 338         char   *data;
 339
 340         /* Data doesn't come in from just anywhere (e.g debug hook) */
 341         if (ctxp == NULL) {
 342                 error = ENETDOWN;
 343                 goto bad;
 344         }
 345
 346         /* If coming from downstream, decode it to a channel */
 347         dlci = ctxp->dlci;
 348         if (dlci == -1)
 349                 return (ngfrm_decode(NG_HOOK_NODE(hook), item));
 350
 351         NGI_GET_M(item, m);
 352         /* Derive the softc we will need */
 353         sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 354
 355         /* If there is no live channel, throw it away */
 356         if ((sc->downstream.hook == NULL)
 357             || ((ctxp->flags & CHAN_ACTIVE) == 0)) {
 358                 error = ENETDOWN;
 359                 goto bad;
 360         }
 361
 362         /* Store the DLCI on the front of the packet */
 363         alen = sc->addrlen;
 364         if (alen == 0)
 365                 alen = 2;       /* default value for transmit */
 366         M_PREPEND(m, alen, MB_DONTWAIT);
 367         if (m == NULL) {
 368                 error = ENOBUFS;
 369                 goto bad;
 370         }
 371         data = mtod(m, char *);
 372
 373         /*
 374          * Shift the lowest bits into the address field untill we are done.
 375          * First byte is MSBits of addr so work backwards.
 376          */
 377         switch (alen) {
 378         case 2:
 379                 data[0] = data[1] = '\0';
 380                 SHIFTOUT(makeup + 1, data[1], dlci);
 381                 SHIFTOUT(makeup + 0, data[0], dlci);
 382                 data[1] |= BYTEX_EA;
 383                 break;
 384         case 3:
 385                 data[0] = data[1] = data[2] = '\0';
 386                 SHIFTOUT(makeup + 3, data[2], dlci);    /* 3 and 2 is correct */
 387                 SHIFTOUT(makeup + 1, data[1], dlci);
 388                 SHIFTOUT(makeup + 0, data[0], dlci);
 389                 data[2] |= BYTEX_EA;
 390                 break;
 391         case 4:
 392                 data[0] = data[1] = data[2] = data[3] = '\0';
 393                 SHIFTOUT(makeup + 3, data[3], dlci);
 394                 SHIFTOUT(makeup + 2, data[2], dlci);
 395                 SHIFTOUT(makeup + 1, data[1], dlci);
 396                 SHIFTOUT(makeup + 0, data[0], dlci);
 397                 data[3] |= BYTEX_EA;
 398                 break;
 399         default:
 400                 panic(__func__);
 401         }
 402
 403         /* Send it */
 404         NG_FWD_NEW_DATA(error, item, sc->downstream.hook, m);
 405         return (error);
 406
 407 bad:
 408         NG_FREE_ITEM(item);
 409         NG_FREE_M(m);
 410         return (error);
 411 }
 412
 413 /*
 414  * Decode an incoming frame coming from the switch
 415  */
 416 static int
 417 ngfrm_decode(node_p node, item_p item)
 418 {
 419         const sc_p  sc = NG_NODE_PRIVATE(node);
 420         char       *data;
 421         int         alen;
 422         u_int       dlci = 0;
 423         int         error = 0;
 424         int         ctxnum;
 425         struct mbuf *m;
 426
 427         NGI_GET_M(item, m);
 428         if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
 429                 error = ENOBUFS;
 430                 goto out;
 431         }
 432         data = mtod(m, char *);
 433         if ((alen = sc->addrlen) == 0) {
 434                 sc->addrlen = alen = ngfrm_addrlen(data);
 435         }
 436         switch (alen) {
 437         case 2:
 438                 SHIFTIN(makeup + 0, data[0], dlci);
 439                 SHIFTIN(makeup + 1, data[1], dlci);
 440                 break;
 441         case 3:
 442                 SHIFTIN(makeup + 0, data[0], dlci);
 443                 SHIFTIN(makeup + 1, data[1], dlci);
 444                 SHIFTIN(makeup + 3, data[2], dlci);     /* 3 and 2 is correct */
 445                 break;
 446         case 4:
 447                 SHIFTIN(makeup + 0, data[0], dlci);
 448                 SHIFTIN(makeup + 1, data[1], dlci);
 449                 SHIFTIN(makeup + 2, data[2], dlci);
 450                 SHIFTIN(makeup + 3, data[3], dlci);
 451                 break;
 452         default:
 453                 error = EINVAL;
 454                 goto out;
 455         }
 456
 457         if (dlci > 1023) {
 458                 error = EINVAL;
 459                 goto out;
 460         }
 461         ctxnum = sc->ALT[dlci];
 462         if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) {
 463                 /* Send it */
 464                 m_adj(m, alen);
 465                 NG_FWD_NEW_DATA(error, item, sc->channel[ctxnum].hook, m);
 466                 return (error);
 467         } else {
 468                 error = ENETDOWN;
 469         }
 470 out:
 471         NG_FREE_ITEM(item);
 472         NG_FREE_M(m);
 473         return (error);
 474 }
 475
 476 /*
 477  * Shutdown node
 478  */
 479 static int
 480 ngfrm_shutdown(node_p node)
 481 {
 482         const sc_p sc = NG_NODE_PRIVATE(node);
 483
 484         NG_NODE_SET_PRIVATE(node, NULL);
 485         FREE(sc, M_NETGRAPH);
 486         NG_NODE_UNREF(node);
 487         return (0);
 488 }
 489
 490 /*
 491  * Hook disconnection
 492  *
 493  * Invalidate the private data associated with this dlci.
 494  * For this type, removal of the last link resets tries to destroy the node.
 495  */
 496 static int
 497 ngfrm_disconnect(hook_p hook)
 498 {
 499         const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 500         struct ctxinfo *const cp = NG_HOOK_PRIVATE(hook);
 501         int dlci;
 502
 503         /* If it's a regular dlci hook, then free resources etc.. */
 504         if (cp != NULL) {
 505                 cp->hook = NULL;
 506                 dlci = cp->dlci;
 507                 if (dlci != -1)
 508                         sc->ALT[dlci] = 0;
 509                 cp->flags = 0;
 510                 sc->datahooks--;
 511         }
 512         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 513         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
 514                 ng_rmnode_self(NG_HOOK_NODE(hook));
 515         return (0);
 516 }