| 1 | /* @(#)if_sl.c 7.2 (Berkeley) %G% */ |
| 2 | |
| 3 | /* |
| 4 | * Serial Line interface |
| 5 | * |
| 6 | * Rick Adams |
| 7 | * Center for Seismic Studies |
| 8 | * 1300 N 17th Street, Suite 1450 |
| 9 | * Arlington, Virginia 22209 |
| 10 | * (703)276-7900 |
| 11 | * rick@seismo.ARPA |
| 12 | * seismo!rick |
| 13 | * |
| 14 | * Pounded on heavily by Chris Torek (chris@mimsy.umd.edu, umcp-cs!chris). |
| 15 | * N.B.: this belongs in netinet, not net, the way it stands now. |
| 16 | * Should have a link-layer type designation, but wouldn't be |
| 17 | * backwards-compatible. |
| 18 | * |
| 19 | * Converted to 4.3BSD Beta by Chris Torek. |
| 20 | * Other changes made at Berkeley, based in part on code by Kirk Smith. |
| 21 | */ |
| 22 | |
| 23 | /* $Header: if_sl.c,v 1.12 85/12/20 21:54:55 chris Exp $ */ |
| 24 | /* from if_sl.c,v 1.11 84/10/04 12:54:47 rick Exp */ |
| 25 | |
| 26 | #include "sl.h" |
| 27 | #if NSL > 0 |
| 28 | |
| 29 | #include "param.h" |
| 30 | #include "mbuf.h" |
| 31 | #include "buf.h" |
| 32 | #include "dk.h" |
| 33 | #include "socket.h" |
| 34 | #include "ioctl.h" |
| 35 | #include "file.h" |
| 36 | #include "tty.h" |
| 37 | #include "errno.h" |
| 38 | |
| 39 | #include "if.h" |
| 40 | #include "netisr.h" |
| 41 | #include "route.h" |
| 42 | #if INET |
| 43 | #include "../netinet/in.h" |
| 44 | #include "../netinet/in_systm.h" |
| 45 | #include "../netinet/in_var.h" |
| 46 | #include "../netinet/ip.h" |
| 47 | #endif |
| 48 | |
| 49 | #ifdef vax |
| 50 | #include "../vax/mtpr.h" |
| 51 | #endif vax |
| 52 | |
| 53 | /* |
| 54 | * N.B.: SLMTU is now a hard limit on input packet size. |
| 55 | * SLMTU must be <= CLBYTES - sizeof(struct ifnet *). |
| 56 | */ |
| 57 | #define SLMTU 1006 |
| 58 | #define SLIP_HIWAT 1000 /* don't start a new packet if HIWAT on queue */ |
| 59 | #define CLISTRESERVE 1000 /* Can't let clists get too low */ |
| 60 | |
| 61 | struct sl_softc { |
| 62 | struct ifnet sc_if; /* network-visible interface */ |
| 63 | short sc_flags; /* see below */ |
| 64 | short sc_ilen; /* length of input-packet-so-far */ |
| 65 | struct tty *sc_ttyp; /* pointer to tty structure */ |
| 66 | char *sc_mp; /* pointer to next available buf char */ |
| 67 | char *sc_buf; /* input buffer */ |
| 68 | } sl_softc[NSL]; |
| 69 | |
| 70 | /* flags */ |
| 71 | #define SC_ESCAPED 0x0001 /* saw a FRAME_ESCAPE */ |
| 72 | #define SC_OACTIVE 0x0002 /* output tty is active */ |
| 73 | |
| 74 | #define FRAME_END 0300 /* Frame End */ |
| 75 | #define FRAME_ESCAPE 0333 /* Frame Esc */ |
| 76 | #define TRANS_FRAME_END 0334 /* transposed frame end */ |
| 77 | #define TRANS_FRAME_ESCAPE 0335 /* transposed frame esc */ |
| 78 | |
| 79 | #define t_sc T_LINEP |
| 80 | |
| 81 | int sloutput(), slioctl(), ttrstrt(); |
| 82 | |
| 83 | /* |
| 84 | * Called from boot code to establish sl interfaces. |
| 85 | */ |
| 86 | slattach() |
| 87 | { |
| 88 | register struct sl_softc *sc; |
| 89 | register int i = 0; |
| 90 | |
| 91 | for (sc = sl_softc; i < NSL; sc++) { |
| 92 | sc->sc_if.if_name = "sl"; |
| 93 | sc->sc_if.if_unit = i++; |
| 94 | sc->sc_if.if_mtu = SLMTU; |
| 95 | sc->sc_if.if_flags = IFF_POINTOPOINT; |
| 96 | sc->sc_if.if_ioctl = slioctl; |
| 97 | sc->sc_if.if_output = sloutput; |
| 98 | sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN; |
| 99 | if_attach(&sc->sc_if); |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | /* |
| 104 | * Line specific open routine. |
| 105 | * Attach the given tty to the first available sl unit. |
| 106 | */ |
| 107 | /* ARGSUSED */ |
| 108 | slopen(dev, tp) |
| 109 | dev_t dev; |
| 110 | register struct tty *tp; |
| 111 | { |
| 112 | register struct sl_softc *sc; |
| 113 | register int nsl; |
| 114 | |
| 115 | if (!suser()) |
| 116 | return (EPERM); |
| 117 | if (tp->t_line == SLIPDISC) |
| 118 | return (EBUSY); |
| 119 | |
| 120 | for (nsl = 0, sc = sl_softc; nsl < NSL; nsl++, sc++) |
| 121 | if (sc->sc_ttyp == NULL) { |
| 122 | sc->sc_flags = 0; |
| 123 | sc->sc_ilen = 0; |
| 124 | if (slinit(sc) == 0) |
| 125 | return (ENOBUFS); |
| 126 | tp->t_sc = (caddr_t)sc; |
| 127 | sc->sc_ttyp = tp; |
| 128 | ttyflush(tp, FREAD | FWRITE); |
| 129 | return (0); |
| 130 | } |
| 131 | |
| 132 | return (ENXIO); |
| 133 | } |
| 134 | |
| 135 | /* |
| 136 | * Line specific close routine. |
| 137 | * Detach the tty from the sl unit. |
| 138 | * Mimics part of ttyclose(). |
| 139 | */ |
| 140 | slclose(tp) |
| 141 | struct tty *tp; |
| 142 | { |
| 143 | register struct sl_softc *sc; |
| 144 | int s; |
| 145 | |
| 146 | ttywflush(tp); |
| 147 | tp->t_line = 0; |
| 148 | s = splimp(); /* paranoid; splnet probably ok */ |
| 149 | sc = (struct sl_softc *)tp->t_sc; |
| 150 | if (sc != NULL) { |
| 151 | if_down(&sc->sc_if); |
| 152 | sc->sc_ttyp = NULL; |
| 153 | tp->t_sc = NULL; |
| 154 | MCLFREE((struct mbuf *)sc->sc_buf); |
| 155 | sc->sc_buf = 0; |
| 156 | } |
| 157 | splx(s); |
| 158 | } |
| 159 | |
| 160 | /* |
| 161 | * Line specific (tty) ioctl routine. |
| 162 | * Provide a way to get the sl unit number. |
| 163 | */ |
| 164 | /* ARGSUSED */ |
| 165 | sltioctl(tp, cmd, data, flag) |
| 166 | struct tty *tp; |
| 167 | caddr_t data; |
| 168 | { |
| 169 | |
| 170 | if (cmd == TIOCGETD) { |
| 171 | *(int *)data = ((struct sl_softc *)tp->t_sc)->sc_if.if_unit; |
| 172 | return (0); |
| 173 | } |
| 174 | return (-1); |
| 175 | } |
| 176 | |
| 177 | /* |
| 178 | * Queue a packet. Start transmission if not active. |
| 179 | */ |
| 180 | sloutput(ifp, m, dst) |
| 181 | register struct ifnet *ifp; |
| 182 | register struct mbuf *m; |
| 183 | struct sockaddr *dst; |
| 184 | { |
| 185 | register struct sl_softc *sc; |
| 186 | int s; |
| 187 | |
| 188 | /* |
| 189 | * `Cannot happen' (see slioctl). Someday we will extend |
| 190 | * the line protocol to support other address families. |
| 191 | */ |
| 192 | if (dst->sa_family != AF_INET) { |
| 193 | printf("sl%d: af%d not supported\n", ifp->if_unit, |
| 194 | dst->sa_family); |
| 195 | m_freem(m); |
| 196 | return (EAFNOSUPPORT); |
| 197 | } |
| 198 | |
| 199 | sc = &sl_softc[ifp->if_unit]; |
| 200 | if (sc->sc_ttyp == NULL) { |
| 201 | m_freem(m); |
| 202 | return (ENETDOWN); /* sort of */ |
| 203 | } |
| 204 | if ((sc->sc_ttyp->t_state & TS_CARR_ON) == 0) { |
| 205 | m_freem(m); |
| 206 | return (EHOSTUNREACH); |
| 207 | } |
| 208 | s = splimp(); |
| 209 | if (IF_QFULL(&ifp->if_snd)) { |
| 210 | IF_DROP(&ifp->if_snd); |
| 211 | splx(s); |
| 212 | m_freem(m); |
| 213 | sc->sc_if.if_oerrors++; |
| 214 | return (ENOBUFS); |
| 215 | } |
| 216 | IF_ENQUEUE(&ifp->if_snd, m); |
| 217 | if ((sc->sc_flags & SC_OACTIVE) == 0) { |
| 218 | splx(s); |
| 219 | slstart(sc->sc_ttyp); |
| 220 | } else |
| 221 | splx(s); |
| 222 | return (0); |
| 223 | } |
| 224 | |
| 225 | /* |
| 226 | * Start output on interface. Get another datagram |
| 227 | * to send from the interface queue and map it to |
| 228 | * the interface before starting output. |
| 229 | */ |
| 230 | slstart(tp) |
| 231 | register struct tty *tp; |
| 232 | { |
| 233 | register struct sl_softc *sc = (struct sl_softc *)tp->t_sc; |
| 234 | register struct mbuf *m; |
| 235 | register int len; |
| 236 | register u_char *cp; |
| 237 | int flush, nd, np, n, s; |
| 238 | struct mbuf *m2; |
| 239 | extern int cfreecount; |
| 240 | |
| 241 | for (;;) { |
| 242 | /* |
| 243 | * If there is more in the output queue, just send it now. |
| 244 | * We are being called in lieu of ttstart and must do what |
| 245 | * it would. |
| 246 | */ |
| 247 | if (tp->t_outq.c_cc > 0) |
| 248 | ttstart(tp); |
| 249 | if (tp->t_outq.c_cc > SLIP_HIWAT) |
| 250 | return; |
| 251 | |
| 252 | /* |
| 253 | * This happens briefly when the line shuts down. |
| 254 | */ |
| 255 | if (sc == NULL) |
| 256 | return; |
| 257 | |
| 258 | /* |
| 259 | * If system is getting low on clists |
| 260 | * and we have something running already, stop here. |
| 261 | */ |
| 262 | if (cfreecount < CLISTRESERVE + SLMTU && |
| 263 | sc->sc_flags & SC_OACTIVE) |
| 264 | return; |
| 265 | |
| 266 | /* |
| 267 | * Get a packet and send it to the interface. |
| 268 | */ |
| 269 | s = splimp(); |
| 270 | IF_DEQUEUE(&sc->sc_if.if_snd, m); |
| 271 | if (m == NULL) { |
| 272 | if (tp->t_outq.c_cc == 0) |
| 273 | sc->sc_flags &= ~SC_OACTIVE; |
| 274 | splx(s); |
| 275 | return; |
| 276 | } |
| 277 | flush = !(sc->sc_flags & SC_OACTIVE); |
| 278 | sc->sc_flags |= SC_OACTIVE; |
| 279 | splx(s); |
| 280 | |
| 281 | /* |
| 282 | * The extra FRAME_END will start up a new packet, and thus |
| 283 | * will flush any accumulated garbage. We do this whenever |
| 284 | * the line may have been idle for some time. |
| 285 | */ |
| 286 | if (flush) |
| 287 | (void) putc(FRAME_END, &tp->t_outq); |
| 288 | |
| 289 | while (m) { |
| 290 | cp = mtod(m, u_char *); |
| 291 | len = m->m_len; |
| 292 | while (len > 0) { |
| 293 | /* |
| 294 | * Find out how many bytes in the string we can |
| 295 | * handle without doing something special. |
| 296 | */ |
| 297 | nd = locc(FRAME_ESCAPE, len, cp); |
| 298 | np = locc(FRAME_END, len, cp); |
| 299 | n = len - MAX(nd, np); |
| 300 | if (n) { |
| 301 | /* |
| 302 | * Put n characters at once |
| 303 | * into the tty output queue. |
| 304 | */ |
| 305 | if (b_to_q((char *)cp, n, &tp->t_outq)) |
| 306 | break; |
| 307 | len -= n; |
| 308 | cp += n; |
| 309 | } |
| 310 | /* |
| 311 | * If there are characters left in the mbuf, |
| 312 | * the first one must be special.. |
| 313 | * Put it out in a different form. |
| 314 | */ |
| 315 | if (len) { |
| 316 | if (putc(FRAME_ESCAPE, &tp->t_outq)) |
| 317 | break; |
| 318 | if (putc(*cp == FRAME_ESCAPE ? |
| 319 | TRANS_FRAME_ESCAPE : TRANS_FRAME_END, |
| 320 | &tp->t_outq)) { |
| 321 | (void) unputc(&tp->t_outq); |
| 322 | break; |
| 323 | } |
| 324 | cp++; |
| 325 | len--; |
| 326 | } |
| 327 | } |
| 328 | MFREE(m, m2); |
| 329 | m = m2; |
| 330 | } |
| 331 | |
| 332 | if (putc(FRAME_END, &tp->t_outq)) { |
| 333 | /* |
| 334 | * Not enough room. Remove a char to make room |
| 335 | * and end the packet normally. |
| 336 | * If you get many collisions (more than one or two |
| 337 | * a day) you probably do not have enough clists |
| 338 | * and you should increase "nclist" in param.c. |
| 339 | */ |
| 340 | (void) unputc(&tp->t_outq); |
| 341 | (void) putc(FRAME_END, &tp->t_outq); |
| 342 | sc->sc_if.if_collisions++; |
| 343 | } else |
| 344 | sc->sc_if.if_opackets++; |
| 345 | } |
| 346 | } |
| 347 | |
| 348 | slinit(sc) |
| 349 | register struct sl_softc *sc; |
| 350 | { |
| 351 | struct mbuf *p; |
| 352 | |
| 353 | if (sc->sc_buf == (char *) 0) { |
| 354 | int s = splimp(); |
| 355 | |
| 356 | MCLALLOC(p, 1); |
| 357 | splx(s); |
| 358 | if (p) { |
| 359 | sc->sc_buf = (char *)p; |
| 360 | sc->sc_mp = sc->sc_buf + sizeof(struct ifnet *); |
| 361 | } else { |
| 362 | printf("sl%d: can't allocate buffer\n", sc - sl_softc); |
| 363 | sc->sc_if.if_flags &= ~IFF_UP; |
| 364 | return (0); |
| 365 | } |
| 366 | } |
| 367 | return (1); |
| 368 | } |
| 369 | |
| 370 | /* |
| 371 | * Copy data buffer to mbuf chain; add ifnet pointer ifp. |
| 372 | */ |
| 373 | struct mbuf * |
| 374 | sl_btom(sc, len, ifp) |
| 375 | struct sl_softc *sc; |
| 376 | register int len; |
| 377 | struct ifnet *ifp; |
| 378 | { |
| 379 | register caddr_t cp; |
| 380 | register struct mbuf *m, **mp; |
| 381 | register unsigned count; |
| 382 | struct mbuf *top = NULL; |
| 383 | |
| 384 | cp = sc->sc_buf + sizeof(struct ifnet *); |
| 385 | mp = ⊤ |
| 386 | while (len > 0) { |
| 387 | MGET(m, M_DONTWAIT, MT_DATA); |
| 388 | if ((*mp = m) == NULL) { |
| 389 | m_freem(top); |
| 390 | return (NULL); |
| 391 | } |
| 392 | if (ifp) |
| 393 | m->m_off += sizeof(ifp); |
| 394 | /* |
| 395 | * If we have at least NBPG bytes, |
| 396 | * allocate a new page. Swap the current buffer page |
| 397 | * with the new one. We depend on having a space |
| 398 | * left at the beginning of the buffer |
| 399 | * for the interface pointer. |
| 400 | */ |
| 401 | if (len >= NBPG) { |
| 402 | MCLGET(m); |
| 403 | if (m->m_len == CLBYTES) { |
| 404 | cp = mtod(m, char *); |
| 405 | m->m_off = (int)sc->sc_buf - (int)m; |
| 406 | sc->sc_buf = cp; |
| 407 | if (ifp) { |
| 408 | m->m_off += sizeof(ifp); |
| 409 | count = MIN(len, |
| 410 | CLBYTES - sizeof(struct ifnet *)); |
| 411 | } else |
| 412 | count = MIN(len, CLBYTES); |
| 413 | goto nocopy; |
| 414 | } |
| 415 | } |
| 416 | if (ifp) |
| 417 | count = MIN(len, MLEN - sizeof(ifp)); |
| 418 | else |
| 419 | count = MIN(len, MLEN); |
| 420 | bcopy(cp, mtod(m, caddr_t), count); |
| 421 | nocopy: |
| 422 | m->m_len = count; |
| 423 | if (ifp) { |
| 424 | m->m_off -= sizeof(ifp); |
| 425 | m->m_len += sizeof(ifp); |
| 426 | *mtod(m, struct ifnet **) = ifp; |
| 427 | ifp = NULL; |
| 428 | } |
| 429 | cp += count; |
| 430 | len -= count; |
| 431 | mp = &m->m_next; |
| 432 | } |
| 433 | return (top); |
| 434 | } |
| 435 | |
| 436 | /* |
| 437 | * tty interface receiver interrupt. |
| 438 | */ |
| 439 | slinput(c, tp) |
| 440 | register int c; |
| 441 | register struct tty *tp; |
| 442 | { |
| 443 | register struct sl_softc *sc; |
| 444 | register struct mbuf *m; |
| 445 | int s; |
| 446 | |
| 447 | tk_nin++; |
| 448 | sc = (struct sl_softc *)tp->t_sc; |
| 449 | if (sc == NULL) |
| 450 | return; |
| 451 | |
| 452 | c &= 0xff; |
| 453 | if (sc->sc_flags & SC_ESCAPED) { |
| 454 | sc->sc_flags &= ~SC_ESCAPED; |
| 455 | switch (c) { |
| 456 | |
| 457 | case TRANS_FRAME_ESCAPE: |
| 458 | c = FRAME_ESCAPE; |
| 459 | break; |
| 460 | |
| 461 | case TRANS_FRAME_END: |
| 462 | c = FRAME_END; |
| 463 | break; |
| 464 | |
| 465 | default: |
| 466 | sc->sc_if.if_ierrors++; |
| 467 | sc->sc_mp = sc->sc_buf + sizeof(struct ifnet *); |
| 468 | sc->sc_ilen = 0; |
| 469 | return; |
| 470 | } |
| 471 | } else { |
| 472 | switch (c) { |
| 473 | |
| 474 | case FRAME_END: |
| 475 | if (sc->sc_ilen == 0) /* ignore */ |
| 476 | return; |
| 477 | m = sl_btom(sc, sc->sc_ilen, &sc->sc_if); |
| 478 | if (m == NULL) { |
| 479 | sc->sc_if.if_ierrors++; |
| 480 | return; |
| 481 | } |
| 482 | sc->sc_mp = sc->sc_buf + sizeof(struct ifnet *); |
| 483 | sc->sc_ilen = 0; |
| 484 | sc->sc_if.if_ipackets++; |
| 485 | s = splimp(); |
| 486 | if (IF_QFULL(&ipintrq)) { |
| 487 | IF_DROP(&ipintrq); |
| 488 | sc->sc_if.if_ierrors++; |
| 489 | m_freem(m); |
| 490 | } else { |
| 491 | IF_ENQUEUE(&ipintrq, m); |
| 492 | schednetisr(NETISR_IP); |
| 493 | } |
| 494 | splx(s); |
| 495 | return; |
| 496 | |
| 497 | case FRAME_ESCAPE: |
| 498 | sc->sc_flags |= SC_ESCAPED; |
| 499 | return; |
| 500 | } |
| 501 | } |
| 502 | if (++sc->sc_ilen > SLMTU) { |
| 503 | sc->sc_if.if_ierrors++; |
| 504 | sc->sc_mp = sc->sc_buf + sizeof(struct ifnet *); |
| 505 | sc->sc_ilen = 0; |
| 506 | return; |
| 507 | } |
| 508 | *sc->sc_mp++ = c; |
| 509 | } |
| 510 | |
| 511 | /* |
| 512 | * Process an ioctl request. |
| 513 | */ |
| 514 | slioctl(ifp, cmd, data) |
| 515 | register struct ifnet *ifp; |
| 516 | int cmd; |
| 517 | caddr_t data; |
| 518 | { |
| 519 | register struct ifaddr *ifa = (struct ifaddr *)data; |
| 520 | int s = splimp(), error = 0; |
| 521 | |
| 522 | switch (cmd) { |
| 523 | |
| 524 | case SIOCSIFADDR: |
| 525 | if (ifa->ifa_addr.sa_family == AF_INET) |
| 526 | ifp->if_flags |= IFF_UP; |
| 527 | else |
| 528 | error = EAFNOSUPPORT; |
| 529 | break; |
| 530 | |
| 531 | case SIOCSIFDSTADDR: |
| 532 | if (ifa->ifa_addr.sa_family != AF_INET) |
| 533 | error = EAFNOSUPPORT; |
| 534 | break; |
| 535 | |
| 536 | default: |
| 537 | error = EINVAL; |
| 538 | } |
| 539 | splx(s); |
| 540 | return (error); |
| 541 | } |
| 542 | #endif |