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  * $Whistle: ng_frame_relay.c,v 1.20 1999/11/01 09:24:51 julian Exp $
  41  */
  42
  43 /*
  44  * This node implements the frame relay protocol, not including
  45  * the LMI line management. This means basically keeping track
  46  * of which DLCI's are active, doing frame (de)multiplexing, etc.
  47  *
  48  * It has a 'downstream' hook that goes to the line, and a
  49  * hook for each DLCI (eg, 'dlci16').
  50  */
  51
  52 #include <sys/param.h>
  53 #include <sys/systm.h>
  54 #include <sys/kernel.h>
  55 #include <sys/errno.h>
  56 #include <sys/malloc.h>
  57 #include <sys/mbuf.h>
  58 #include <sys/syslog.h>
  59 #include <sys/ctype.h>
  60 #include <machine/clock.h>
  61
  62 #include <netgraph/ng_message.h>
  63 #include <netgraph/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 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_rmnode;
 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, struct mbuf * m, meta_p meta);
 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         NG_VERSION,
 142         NG_FRAMERELAY_NODE_TYPE,
 143         NULL,
 144         ngfrm_constructor,
 145         NULL,
 146         ngfrm_rmnode,
 147         ngfrm_newhook,
 148         NULL,
 149         NULL,
 150         ngfrm_rcvdata,
 151         ngfrm_rcvdata,
 152         ngfrm_disconnect,
 153         NULL
 154 };
 155 NETGRAPH_INIT(framerelay, &typestruct);
 156
 157 /*
 158  * Given a DLCI, return the index of the  context table entry for it,
 159  * Allocating a new one if needs be, or -1 if none available.
 160  */
 161 static int
 162 ngfrm_allocate_CTX(sc_p sc, int dlci)
 163 {
 164         u_int   ctxnum = -1;    /* what ctx number we are using */
 165         volatile struct ctxinfo *CTXp = NULL;
 166
 167         /* Sanity check the dlci value */
 168         if (dlci > 1023)
 169                 return (-1);
 170
 171         /* Check to see if we already have an entry for this DLCI */
 172         if (sc->ALT[dlci]) {
 173                 if ((ctxnum = sc->ALT[dlci] & CTX_VALUE) < MAX_CT) {
 174                         CTXp = sc->channel + ctxnum;
 175                 } else {
 176                         ctxnum = -1;
 177                         sc->ALT[dlci] = 0;      /* paranoid but... */
 178                 }
 179         }
 180
 181         /*
 182          * If the index has no valid entry yet, then we need to allocate a
 183          * CTX number to it
 184          */
 185         if (CTXp == NULL) {
 186                 for (ctxnum = 0; ctxnum < MAX_CT; ctxnum++) {
 187                         /*
 188                          * If the VALID flag is empty it is unused
 189                          */
 190                         if ((sc->channel[ctxnum].flags & CHAN_VALID) == 0) {
 191                                 bzero(sc->channel + ctxnum,
 192                                       sizeof(struct ctxinfo));
 193                                 CTXp = sc->channel + ctxnum;
 194                                 sc->ALT[dlci] = ctxnum | CTX_VALID;
 195                                 sc->channel[ctxnum].dlci = dlci;
 196                                 sc->channel[ctxnum].flags = CHAN_VALID;
 197                                 break;
 198                         }
 199                 }
 200         }
 201
 202         /*
 203          * If we still don't have a CTX pointer, then we never found a free
 204          * spot so give up now..
 205          */
 206         if (!CTXp) {
 207                 log(LOG_ERR, "No CTX available for dlci %d\n", dlci);
 208                 return (-1);
 209         }
 210         return (ctxnum);
 211 }
 212
 213 /*
 214  * Node constructor
 215  */
 216 static int
 217 ngfrm_constructor(node_p *nodep)
 218 {
 219         sc_p sc;
 220         int error = 0;
 221
 222         sc = kmalloc(sizeof(*sc), M_NETGRAPH, M_NOWAIT | M_ZERO);
 223         if (!sc)
 224                 return (ENOMEM);
 225         if ((error = ng_make_node_common(&typestruct, nodep))) {
 226                 kfree(sc, M_NETGRAPH);
 227                 return (error);
 228         }
 229         sc->addrlen = 2;        /* default */
 230
 231         /* Link the node and our private info */
 232         (*nodep)->private = sc;
 233         sc->node = *nodep;
 234         return (0);
 235 }
 236
 237 /*
 238  * Add a new hook
 239  *
 240  * We allow hooks called "debug", "downstream" and dlci[0-1023]
 241  * The hook's private info points to our stash of info about that
 242  * channel. A NULL pointer is debug and a DLCI of -1 means downstream.
 243  */
 244 static int
 245 ngfrm_newhook(node_p node, hook_p hook, const char *name)
 246 {
 247         const sc_p sc = node->private;
 248         const char *cp;
 249         char *eptr;
 250         int dlci = 0;
 251         int ctxnum;
 252
 253         /* Check if it's our friend the control hook */
 254         if (strcmp(name, NG_FRAMERELAY_HOOK_DEBUG) == 0) {
 255                 hook->private = NULL;   /* paranoid */
 256                 return (0);
 257         }
 258
 259         /*
 260          * All other hooks either start with 'dlci' and have a decimal
 261          * trailing channel number up to 4 digits, or are the downstream
 262          * hook.
 263          */
 264         if (strncmp(name, NG_FRAMERELAY_HOOK_DLCI,
 265             strlen(NG_FRAMERELAY_HOOK_DLCI)) != 0) {
 266
 267                 /* It must be the downstream connection */
 268                 if (strcmp(name, NG_FRAMERELAY_HOOK_DOWNSTREAM) != 0)
 269                         return EINVAL;
 270
 271                 /* Make sure we haven't already got one (paranoid) */
 272                 if (sc->downstream.hook)
 273                         return (EADDRINUSE);
 274
 275                 /* OK add it */
 276                 hook->private = &sc->downstream;
 277                 sc->downstream.hook = hook;
 278                 sc->downstream.dlci = -1;
 279                 sc->downstream.flags |= CHAN_ACTIVE;
 280                 sc->datahooks++;
 281                 return (0);
 282         }
 283
 284         /* Must be a dlci hook at this point */
 285         cp = name + strlen(NG_FRAMERELAY_HOOK_DLCI);
 286         if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 287                 return (EINVAL);
 288         dlci = (int)strtoul(cp, &eptr, 10);
 289         if (*eptr != '\0' || dlci < 0 || dlci > 1023)
 290                 return (EINVAL);
 291
 292         /*
 293          * We have a dlci, now either find it, or allocate it. It's possible
 294          * that we might have seen packets for it already and made an entry
 295          * for it.
 296          */
 297         ctxnum = ngfrm_allocate_CTX(sc, dlci);
 298         if (ctxnum == -1)
 299                 return (ENOBUFS);
 300
 301         /*
 302          * Be paranoid: if it's got a hook already, that dlci is in use .
 303          * Generic code can not catch all the synonyms (e.g. dlci016 vs
 304          * dlci16)
 305          */
 306         if (sc->channel[ctxnum].hook != NULL)
 307                 return (EADDRINUSE);
 308
 309         /*
 310          * Put our hooks into it (pun not intended)
 311          */
 312         sc->channel[ctxnum].flags |= CHAN_ACTIVE;
 313         hook->private = sc->channel + ctxnum;
 314         sc->channel[ctxnum].hook = hook;
 315         sc->datahooks++;
 316         return (0);
 317 }
 318
 319 /*
 320  * Count up the size of the address header if we don't already know
 321  */
 322 static int
 323 ngfrm_addrlen(char *hdr)
 324 {
 325         if (hdr[0] & BYTEX_EA)
 326                 return 0;
 327         if (hdr[1] & BYTEX_EA)
 328                 return 2;
 329         if (hdr[2] & BYTEX_EA)
 330                 return 3;
 331         if (hdr[3] & BYTEX_EA)
 332                 return 4;
 333         return 0;
 334 }
 335
 336 /*
 337  * Receive data packet
 338  */
 339 static int
 340 ngfrm_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
 341 {
 342         struct  ctxinfo *const ctxp = hook->private;
 343         int     error = 0;
 344         int     dlci;
 345         sc_p    sc;
 346         int     alen;
 347         char   *data;
 348
 349         /* Data doesn't come in from just anywhere (e.g debug hook) */
 350         if (ctxp == NULL) {
 351                 error = ENETDOWN;
 352                 goto bad;
 353         }
 354
 355         /* If coming from downstream, decode it to a channel */
 356         dlci = ctxp->dlci;
 357         if (dlci == -1)
 358                 return (ngfrm_decode(hook->node, m, meta));
 359
 360         /* Derive the softc we will need */
 361         sc = hook->node->private;
 362
 363         /* If there is no live channel, throw it away */
 364         if ((sc->downstream.hook == NULL)
 365             || ((ctxp->flags & CHAN_ACTIVE) == 0)) {
 366                 error = ENETDOWN;
 367                 goto bad;
 368         }
 369
 370         /* Store the DLCI on the front of the packet */
 371         alen = sc->addrlen;
 372         if (alen == 0)
 373                 alen = 2;       /* default value for transmit */
 374         M_PREPEND(m, alen, M_NOWAIT);
 375         if (m == NULL) {
 376                 error = ENOBUFS;
 377                 goto bad;
 378         }
 379         data = mtod(m, char *);
 380
 381         /*
 382          * Shift the lowest bits into the address field untill we are done.
 383          * First byte is MSBits of addr so work backwards.
 384          */
 385         switch (alen) {
 386         case 2:
 387                 data[0] = data[1] = '\0';
 388                 SHIFTOUT(makeup + 1, data[1], dlci);
 389                 SHIFTOUT(makeup + 0, data[0], dlci);
 390                 data[1] |= BYTEX_EA;
 391                 break;
 392         case 3:
 393                 data[0] = data[1] = data[2] = '\0';
 394                 SHIFTOUT(makeup + 3, data[2], dlci);    /* 3 and 2 is correct */
 395                 SHIFTOUT(makeup + 1, data[1], dlci);
 396                 SHIFTOUT(makeup + 0, data[0], dlci);
 397                 data[2] |= BYTEX_EA;
 398                 break;
 399         case 4:
 400                 data[0] = data[1] = data[2] = data[3] = '\0';
 401                 SHIFTOUT(makeup + 3, data[3], dlci);
 402                 SHIFTOUT(makeup + 2, data[2], dlci);
 403                 SHIFTOUT(makeup + 1, data[1], dlci);
 404                 SHIFTOUT(makeup + 0, data[0], dlci);
 405                 data[3] |= BYTEX_EA;
 406                 break;
 407         default:
 408                 panic(__func__);
 409         }
 410
 411         /* Send it */
 412         NG_SEND_DATA(error, sc->downstream.hook, m, meta);
 413         return (error);
 414
 415 bad:
 416         NG_FREE_DATA(m, meta);
 417         return (error);
 418 }
 419
 420 /*
 421  * Decode an incoming frame coming from the switch
 422  */
 423 static int
 424 ngfrm_decode(node_p node, struct mbuf *m, meta_p meta)
 425 {
 426         const sc_p  sc = node->private;
 427         char       *data;
 428         int         alen;
 429         u_int       dlci = 0;
 430         int         error = 0;
 431         int         ctxnum;
 432
 433         if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
 434                 error = ENOBUFS;
 435                 goto out;
 436         }
 437         data = mtod(m, char *);
 438         if ((alen = sc->addrlen) == 0) {
 439                 sc->addrlen = alen = ngfrm_addrlen(data);
 440         }
 441         switch (alen) {
 442         case 2:
 443                 SHIFTIN(makeup + 0, data[0], dlci);
 444                 SHIFTIN(makeup + 1, data[1], dlci);
 445                 break;
 446         case 3:
 447                 SHIFTIN(makeup + 0, data[0], dlci);
 448                 SHIFTIN(makeup + 1, data[1], dlci);
 449                 SHIFTIN(makeup + 3, data[2], dlci);     /* 3 and 2 is correct */
 450                 break;
 451         case 4:
 452                 SHIFTIN(makeup + 0, data[0], dlci);
 453                 SHIFTIN(makeup + 1, data[1], dlci);
 454                 SHIFTIN(makeup + 2, data[2], dlci);
 455                 SHIFTIN(makeup + 3, data[3], dlci);
 456                 break;
 457         default:
 458                 error = EINVAL;
 459                 goto out;
 460         }
 461
 462         if (dlci > 1023) {
 463                 error = EINVAL;
 464                 goto out;
 465         }
 466         ctxnum = sc->ALT[dlci];
 467         if ((ctxnum & CTX_VALID) && sc->channel[ctxnum &= CTX_VALUE].hook) {
 468                 /* Send it */
 469                 m_adj(m, alen);
 470                 NG_SEND_DATA(error, sc->channel[ctxnum].hook, m, meta);
 471                 return (error);
 472         } else {
 473                 error = ENETDOWN;
 474         }
 475 out:
 476         NG_FREE_DATA(m, meta);
 477         return (error);
 478 }
 479
 480 /*
 481  * Shutdown node
 482  */
 483 static int
 484 ngfrm_rmnode(node_p node)
 485 {
 486         const sc_p sc = node->private;
 487
 488         node->flags |= NG_INVALID;
 489         ng_cutlinks(node);
 490         ng_unname(node);
 491         node->private = NULL;
 492         kfree(sc, M_NETGRAPH);
 493         ng_unref(node);
 494         return (0);
 495 }
 496
 497 /*
 498  * Hook disconnection
 499  *
 500  * Invalidate the private data associated with this dlci.
 501  * For this type, removal of the last link resets tries to destroy the node.
 502  */
 503 static int
 504 ngfrm_disconnect(hook_p hook)
 505 {
 506         const sc_p sc = hook->node->private;
 507         struct ctxinfo *const cp = hook->private;
 508         int dlci;
 509
 510         /* If it's a regular dlci hook, then free resources etc.. */
 511         if (cp != NULL) {
 512                 cp->hook = NULL;
 513                 dlci = cp->dlci;
 514                 if (dlci != -1)
 515                         sc->ALT[dlci] = 0;
 516                 cp->flags = 0;
 517                 sc->datahooks--;
 518         }
 519         if (hook->node->numhooks == 0)
 520                 ng_rmnode(hook->node);
 521         return (0);
 522 }