uipc_socket2.c revision 1.6
1 /* 2 * Copyright (c) 1982, 1986, 1988, 1990 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * from: @(#)uipc_socket2.c 7.17 (Berkeley) 5/4/91 34 * $Id: uipc_socket2.c,v 1.6 1994/04/25 08:08:58 mycroft Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/proc.h> 40 #include <sys/file.h> 41 #include <sys/buf.h> 42 #include <sys/malloc.h> 43 #include <sys/select.h> 44 #include <sys/mbuf.h> 45 #include <sys/protosw.h> 46 #include <sys/socket.h> 47 #include <sys/socketvar.h> 48 49 /* 50 * Primitive routines for operating on sockets and socket buffers 51 */ 52 53 /* strings for sleep message: */ 54 char netio[] = "netio"; 55 char netcon[] = "netcon"; 56 char netcls[] = "netcls"; 57 58 u_long sb_max = SB_MAX; /* patchable */ 59 60 /* 61 * Procedures to manipulate state flags of socket 62 * and do appropriate wakeups. Normal sequence from the 63 * active (originating) side is that soisconnecting() is 64 * called during processing of connect() call, 65 * resulting in an eventual call to soisconnected() if/when the 66 * connection is established. When the connection is torn down 67 * soisdisconnecting() is called during processing of disconnect() call, 68 * and soisdisconnected() is called when the connection to the peer 69 * is totally severed. The semantics of these routines are such that 70 * connectionless protocols can call soisconnected() and soisdisconnected() 71 * only, bypassing the in-progress calls when setting up a ``connection'' 72 * takes no time. 73 * 74 * From the passive side, a socket is created with 75 * two queues of sockets: so_q0 for connections in progress 76 * and so_q for connections already made and awaiting user acceptance. 77 * As a protocol is preparing incoming connections, it creates a socket 78 * structure queued on so_q0 by calling sonewconn(). When the connection 79 * is established, soisconnected() is called, and transfers the 80 * socket structure to so_q, making it available to accept(). 81 * 82 * If a socket is closed with sockets on either 83 * so_q0 or so_q, these sockets are dropped. 84 * 85 * If higher level protocols are implemented in 86 * the kernel, the wakeups done here will sometimes 87 * cause software-interrupt process scheduling. 88 */ 89 90 soisconnecting(so) 91 register struct socket *so; 92 { 93 94 so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING); 95 so->so_state |= SS_ISCONNECTING; 96 } 97 98 soisconnected(so) 99 register struct socket *so; 100 { 101 register struct socket *head = so->so_head; 102 103 so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING|SS_ISCONFIRMING); 104 so->so_state |= SS_ISCONNECTED; 105 if (head && soqremque(so, 0)) { 106 soqinsque(head, so, 1); 107 sorwakeup(head); 108 wakeup((caddr_t)&head->so_timeo); 109 } else { 110 wakeup((caddr_t)&so->so_timeo); 111 sorwakeup(so); 112 sowwakeup(so); 113 } 114 } 115 116 soisdisconnecting(so) 117 register struct socket *so; 118 { 119 120 so->so_state &= ~SS_ISCONNECTING; 121 so->so_state |= (SS_ISDISCONNECTING|SS_CANTRCVMORE|SS_CANTSENDMORE); 122 wakeup((caddr_t)&so->so_timeo); 123 sowwakeup(so); 124 sorwakeup(so); 125 } 126 127 soisdisconnected(so) 128 register struct socket *so; 129 { 130 131 so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING); 132 so->so_state |= (SS_CANTRCVMORE|SS_CANTSENDMORE); 133 wakeup((caddr_t)&so->so_timeo); 134 sowwakeup(so); 135 sorwakeup(so); 136 } 137 138 /* 139 * When an attempt at a new connection is noted on a socket 140 * which accepts connections, sonewconn is called. If the 141 * connection is possible (subject to space constraints, etc.) 142 * then we allocate a new structure, propoerly linked into the 143 * data structure of the original socket, and return this. 144 * Connstatus may be 0, or SO_ISCONFIRMING, or SO_ISCONNECTED. 145 * 146 * Currently, sonewconn() is defined as sonewconn1() in socketvar.h 147 * to catch calls that are missing the (new) second parameter. 148 */ 149 struct socket * 150 sonewconn1(head, connstatus) 151 register struct socket *head; 152 int connstatus; 153 { 154 register struct socket *so; 155 int soqueue = connstatus ? 1 : 0; 156 157 if (head->so_qlen + head->so_q0len > 3 * head->so_qlimit / 2) 158 return ((struct socket *)0); 159 MALLOC(so, struct socket *, sizeof(*so), M_SOCKET, M_DONTWAIT); 160 if (so == NULL) 161 return ((struct socket *)0); 162 bzero((caddr_t)so, sizeof(*so)); 163 so->so_type = head->so_type; 164 so->so_options = head->so_options &~ SO_ACCEPTCONN; 165 so->so_linger = head->so_linger; 166 so->so_state = head->so_state | SS_NOFDREF; 167 so->so_proto = head->so_proto; 168 so->so_timeo = head->so_timeo; 169 so->so_pgid = head->so_pgid; 170 (void) soreserve(so, head->so_snd.sb_hiwat, head->so_rcv.sb_hiwat); 171 soqinsque(head, so, soqueue); 172 if ((*so->so_proto->pr_usrreq)(so, PRU_ATTACH, 173 (struct mbuf *)0, (struct mbuf *)0, (struct mbuf *)0)) { 174 (void) soqremque(so, soqueue); 175 (void) free((caddr_t)so, M_SOCKET); 176 return ((struct socket *)0); 177 } 178 if (connstatus) { 179 sorwakeup(head); 180 wakeup((caddr_t)&head->so_timeo); 181 so->so_state |= connstatus; 182 } 183 return (so); 184 } 185 186 soqinsque(head, so, q) 187 register struct socket *head, *so; 188 int q; 189 { 190 191 register struct socket **prev; 192 so->so_head = head; 193 if (q == 0) { 194 head->so_q0len++; 195 so->so_q0 = 0; 196 for (prev = &(head->so_q0); *prev; ) 197 prev = &((*prev)->so_q0); 198 } else { 199 head->so_qlen++; 200 so->so_q = 0; 201 for (prev = &(head->so_q); *prev; ) 202 prev = &((*prev)->so_q); 203 } 204 *prev = so; 205 } 206 207 soqremque(so, q) 208 register struct socket *so; 209 int q; 210 { 211 register struct socket *head, *prev, *next; 212 213 head = so->so_head; 214 prev = head; 215 for (;;) { 216 next = q ? prev->so_q : prev->so_q0; 217 if (next == so) 218 break; 219 if (next == 0) 220 return (0); 221 prev = next; 222 } 223 if (q == 0) { 224 prev->so_q0 = next->so_q0; 225 head->so_q0len--; 226 } else { 227 prev->so_q = next->so_q; 228 head->so_qlen--; 229 } 230 next->so_q0 = next->so_q = 0; 231 next->so_head = 0; 232 return (1); 233 } 234 235 /* 236 * Socantsendmore indicates that no more data will be sent on the 237 * socket; it would normally be applied to a socket when the user 238 * informs the system that no more data is to be sent, by the protocol 239 * code (in case PRU_SHUTDOWN). Socantrcvmore indicates that no more data 240 * will be received, and will normally be applied to the socket by a 241 * protocol when it detects that the peer will send no more data. 242 * Data queued for reading in the socket may yet be read. 243 */ 244 245 void 246 socantsendmore(so) 247 struct socket *so; 248 { 249 250 so->so_state |= SS_CANTSENDMORE; 251 sowwakeup(so); 252 } 253 254 void 255 socantrcvmore(so) 256 struct socket *so; 257 { 258 259 so->so_state |= SS_CANTRCVMORE; 260 sorwakeup(so); 261 } 262 263 /* 264 * Socket select/wakeup routines. 265 */ 266 267 /* 268 * Wait for data to arrive at/drain from a socket buffer. 269 */ 270 sbwait(sb) 271 struct sockbuf *sb; 272 { 273 274 sb->sb_flags |= SB_WAIT; 275 return (tsleep((caddr_t)&sb->sb_cc, 276 (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK | PCATCH, netio, 277 sb->sb_timeo)); 278 } 279 280 /* 281 * Lock a sockbuf already known to be locked; 282 * return any error returned from sleep (EINTR). 283 */ 284 sb_lock(sb) 285 register struct sockbuf *sb; 286 { 287 int error; 288 289 while (sb->sb_flags & SB_LOCK) { 290 sb->sb_flags |= SB_WANT; 291 if (error = tsleep((caddr_t)&sb->sb_flags, 292 (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK|PCATCH, 293 netio, 0)) 294 return (error); 295 } 296 sb->sb_flags |= SB_LOCK; 297 return (0); 298 } 299 300 /* 301 * Wakeup processes waiting on a socket buffer. 302 * Do asynchronous notification via SIGIO 303 * if the socket has the SS_ASYNC flag set. 304 */ 305 sowakeup(so, sb) 306 register struct socket *so; 307 register struct sockbuf *sb; 308 { 309 struct proc *p; 310 311 selwakeup(&sb->sb_sel); 312 sb->sb_flags &= ~SB_SEL; 313 if (sb->sb_flags & SB_WAIT) { 314 sb->sb_flags &= ~SB_WAIT; 315 wakeup((caddr_t)&sb->sb_cc); 316 } 317 if (so->so_state & SS_ASYNC) { 318 if (so->so_pgid < 0) 319 gsignal(-so->so_pgid, SIGIO); 320 else if (so->so_pgid > 0 && (p = pfind(so->so_pgid)) != 0) 321 psignal(p, SIGIO); 322 } 323 } 324 325 /* 326 * Socket buffer (struct sockbuf) utility routines. 327 * 328 * Each socket contains two socket buffers: one for sending data and 329 * one for receiving data. Each buffer contains a queue of mbufs, 330 * information about the number of mbufs and amount of data in the 331 * queue, and other fields allowing select() statements and notification 332 * on data availability to be implemented. 333 * 334 * Data stored in a socket buffer is maintained as a list of records. 335 * Each record is a list of mbufs chained together with the m_next 336 * field. Records are chained together with the m_nextpkt field. The upper 337 * level routine soreceive() expects the following conventions to be 338 * observed when placing information in the receive buffer: 339 * 340 * 1. If the protocol requires each message be preceded by the sender's 341 * name, then a record containing that name must be present before 342 * any associated data (mbuf's must be of type MT_SONAME). 343 * 2. If the protocol supports the exchange of ``access rights'' (really 344 * just additional data associated with the message), and there are 345 * ``rights'' to be received, then a record containing this data 346 * should be present (mbuf's must be of type MT_RIGHTS). 347 * 3. If a name or rights record exists, then it must be followed by 348 * a data record, perhaps of zero length. 349 * 350 * Before using a new socket structure it is first necessary to reserve 351 * buffer space to the socket, by calling sbreserve(). This should commit 352 * some of the available buffer space in the system buffer pool for the 353 * socket (currently, it does nothing but enforce limits). The space 354 * should be released by calling sbrelease() when the socket is destroyed. 355 */ 356 357 soreserve(so, sndcc, rcvcc) 358 register struct socket *so; 359 u_long sndcc, rcvcc; 360 { 361 362 if (sbreserve(&so->so_snd, sndcc) == 0) 363 goto bad; 364 if (sbreserve(&so->so_rcv, rcvcc) == 0) 365 goto bad2; 366 if (so->so_rcv.sb_lowat == 0) 367 so->so_rcv.sb_lowat = 1; 368 if (so->so_snd.sb_lowat == 0) 369 so->so_snd.sb_lowat = MCLBYTES; 370 if (so->so_snd.sb_lowat > so->so_snd.sb_hiwat) 371 so->so_snd.sb_lowat = so->so_snd.sb_hiwat; 372 return (0); 373 bad2: 374 sbrelease(&so->so_snd); 375 bad: 376 return (ENOBUFS); 377 } 378 379 /* 380 * Allot mbufs to a sockbuf. 381 * Attempt to scale mbmax so that mbcnt doesn't become limiting 382 * if buffering efficiency is near the normal case. 383 */ 384 sbreserve(sb, cc) 385 struct sockbuf *sb; 386 u_long cc; 387 { 388 389 if (cc > sb_max * MCLBYTES / (MSIZE + MCLBYTES)) 390 return (0); 391 sb->sb_hiwat = cc; 392 sb->sb_mbmax = min(cc * 2, sb_max); 393 if (sb->sb_lowat > sb->sb_hiwat) 394 sb->sb_lowat = sb->sb_hiwat; 395 return (1); 396 } 397 398 /* 399 * Free mbufs held by a socket, and reserved mbuf space. 400 */ 401 sbrelease(sb) 402 struct sockbuf *sb; 403 { 404 405 sbflush(sb); 406 sb->sb_hiwat = sb->sb_mbmax = 0; 407 } 408 409 /* 410 * Routines to add and remove 411 * data from an mbuf queue. 412 * 413 * The routines sbappend() or sbappendrecord() are normally called to 414 * append new mbufs to a socket buffer, after checking that adequate 415 * space is available, comparing the function sbspace() with the amount 416 * of data to be added. sbappendrecord() differs from sbappend() in 417 * that data supplied is treated as the beginning of a new record. 418 * To place a sender's address, optional access rights, and data in a 419 * socket receive buffer, sbappendaddr() should be used. To place 420 * access rights and data in a socket receive buffer, sbappendrights() 421 * should be used. In either case, the new data begins a new record. 422 * Note that unlike sbappend() and sbappendrecord(), these routines check 423 * for the caller that there will be enough space to store the data. 424 * Each fails if there is not enough space, or if it cannot find mbufs 425 * to store additional information in. 426 * 427 * Reliable protocols may use the socket send buffer to hold data 428 * awaiting acknowledgement. Data is normally copied from a socket 429 * send buffer in a protocol with m_copy for output to a peer, 430 * and then removing the data from the socket buffer with sbdrop() 431 * or sbdroprecord() when the data is acknowledged by the peer. 432 */ 433 434 /* 435 * Append mbuf chain m to the last record in the 436 * socket buffer sb. The additional space associated 437 * the mbuf chain is recorded in sb. Empty mbufs are 438 * discarded and mbufs are compacted where possible. 439 */ 440 sbappend(sb, m) 441 struct sockbuf *sb; 442 struct mbuf *m; 443 { 444 register struct mbuf *n; 445 446 if (m == 0) 447 return; 448 if (n = sb->sb_mb) { 449 while (n->m_nextpkt) 450 n = n->m_nextpkt; 451 do { 452 if (n->m_flags & M_EOR) { 453 sbappendrecord(sb, m); /* XXXXXX!!!! */ 454 return; 455 } 456 } while (n->m_next && (n = n->m_next)); 457 } 458 sbcompress(sb, m, n); 459 } 460 461 #ifdef SOCKBUF_DEBUG 462 sbcheck(sb) 463 register struct sockbuf *sb; 464 { 465 register struct mbuf *m; 466 register int len = 0, mbcnt = 0; 467 468 for (m = sb->sb_mb; m; m = m->m_next) { 469 len += m->m_len; 470 mbcnt += MSIZE; 471 if (m->m_flags & M_EXT) 472 mbcnt += m->m_ext.ext_size; 473 if (m->m_nextpkt) 474 panic("sbcheck nextpkt"); 475 } 476 if (len != sb->sb_cc || mbcnt != sb->sb_mbcnt) { 477 printf("cc %d != %d || mbcnt %d != %d\n", len, sb->sb_cc, 478 mbcnt, sb->sb_mbcnt); 479 panic("sbcheck"); 480 } 481 } 482 #endif 483 484 /* 485 * As above, except the mbuf chain 486 * begins a new record. 487 */ 488 sbappendrecord(sb, m0) 489 register struct sockbuf *sb; 490 register struct mbuf *m0; 491 { 492 register struct mbuf *m; 493 494 if (m0 == 0) 495 return; 496 if (m = sb->sb_mb) 497 while (m->m_nextpkt) 498 m = m->m_nextpkt; 499 /* 500 * Put the first mbuf on the queue. 501 * Note this permits zero length records. 502 */ 503 sballoc(sb, m0); 504 if (m) 505 m->m_nextpkt = m0; 506 else 507 sb->sb_mb = m0; 508 m = m0->m_next; 509 m0->m_next = 0; 510 if (m && (m0->m_flags & M_EOR)) { 511 m0->m_flags &= ~M_EOR; 512 m->m_flags |= M_EOR; 513 } 514 sbcompress(sb, m, m0); 515 } 516 517 /* 518 * As above except that OOB data 519 * is inserted at the beginning of the sockbuf, 520 * but after any other OOB data. 521 */ 522 sbinsertoob(sb, m0) 523 register struct sockbuf *sb; 524 register struct mbuf *m0; 525 { 526 register struct mbuf *m; 527 register struct mbuf **mp; 528 529 if (m0 == 0) 530 return; 531 for (mp = &sb->sb_mb; m = *mp; mp = &((*mp)->m_nextpkt)) { 532 again: 533 switch (m->m_type) { 534 535 case MT_OOBDATA: 536 continue; /* WANT next train */ 537 538 case MT_CONTROL: 539 if (m = m->m_next) 540 goto again; /* inspect THIS train further */ 541 } 542 break; 543 } 544 /* 545 * Put the first mbuf on the queue. 546 * Note this permits zero length records. 547 */ 548 sballoc(sb, m0); 549 m0->m_nextpkt = *mp; 550 *mp = m0; 551 m = m0->m_next; 552 m0->m_next = 0; 553 if (m && (m0->m_flags & M_EOR)) { 554 m0->m_flags &= ~M_EOR; 555 m->m_flags |= M_EOR; 556 } 557 sbcompress(sb, m, m0); 558 } 559 560 /* 561 * Append address and data, and optionally, control (ancillary) data 562 * to the receive queue of a socket. If present, 563 * m0 must include a packet header with total length. 564 * Returns 0 if no space in sockbuf or insufficient mbufs. 565 */ 566 sbappendaddr(sb, asa, m0, control) 567 register struct sockbuf *sb; 568 struct sockaddr *asa; 569 struct mbuf *m0, *control; 570 { 571 register struct mbuf *m, *n; 572 int space = asa->sa_len; 573 574 if (m0 && (m0->m_flags & M_PKTHDR) == 0) 575 panic("sbappendaddr"); 576 if (m0) 577 space += m0->m_pkthdr.len; 578 for (n = control; n; n = n->m_next) { 579 space += n->m_len; 580 if (n->m_next == 0) /* keep pointer to last control buf */ 581 break; 582 } 583 if (space > sbspace(sb)) 584 return (0); 585 if (asa->sa_len > MLEN) 586 return (0); 587 MGET(m, M_DONTWAIT, MT_SONAME); 588 if (m == 0) 589 return (0); 590 m->m_len = asa->sa_len; 591 bcopy((caddr_t)asa, mtod(m, caddr_t), asa->sa_len); 592 if (n) 593 n->m_next = m0; /* concatenate data to control */ 594 else 595 control = m0; 596 m->m_next = control; 597 for (n = m; n; n = n->m_next) 598 sballoc(sb, n); 599 if (n = sb->sb_mb) { 600 while (n->m_nextpkt) 601 n = n->m_nextpkt; 602 n->m_nextpkt = m; 603 } else 604 sb->sb_mb = m; 605 return (1); 606 } 607 608 sbappendcontrol(sb, m0, control) 609 struct sockbuf *sb; 610 struct mbuf *control, *m0; 611 { 612 register struct mbuf *m, *n; 613 int space = 0; 614 615 if (control == 0) 616 panic("sbappendcontrol"); 617 for (m = control; ; m = m->m_next) { 618 space += m->m_len; 619 if (m->m_next == 0) 620 break; 621 } 622 n = m; /* save pointer to last control buffer */ 623 for (m = m0; m; m = m->m_next) 624 space += m->m_len; 625 if (space > sbspace(sb)) 626 return (0); 627 n->m_next = m0; /* concatenate data to control */ 628 for (m = control; m; m = m->m_next) 629 sballoc(sb, m); 630 if (n = sb->sb_mb) { 631 while (n->m_nextpkt) 632 n = n->m_nextpkt; 633 n->m_nextpkt = control; 634 } else 635 sb->sb_mb = control; 636 return (1); 637 } 638 639 /* 640 * Compress mbuf chain m into the socket 641 * buffer sb following mbuf n. If n 642 * is null, the buffer is presumed empty. 643 */ 644 sbcompress(sb, m, n) 645 register struct sockbuf *sb; 646 register struct mbuf *m, *n; 647 { 648 register int eor = 0; 649 register struct mbuf *o; 650 651 while (m) { 652 eor |= m->m_flags & M_EOR; 653 if (m->m_len == 0 && 654 (eor == 0 || 655 (((o = m->m_next) || (o = n)) && 656 o->m_type == m->m_type))) { 657 m = m_free(m); 658 continue; 659 } 660 if (n && (n->m_flags & (M_EXT | M_EOR)) == 0 && 661 (n->m_data + n->m_len + m->m_len) < &n->m_dat[MLEN] && 662 n->m_type == m->m_type) { 663 bcopy(mtod(m, caddr_t), mtod(n, caddr_t) + n->m_len, 664 (unsigned)m->m_len); 665 n->m_len += m->m_len; 666 sb->sb_cc += m->m_len; 667 m = m_free(m); 668 continue; 669 } 670 if (n) 671 n->m_next = m; 672 else 673 sb->sb_mb = m; 674 sballoc(sb, m); 675 n = m; 676 m->m_flags &= ~M_EOR; 677 m = m->m_next; 678 n->m_next = 0; 679 } 680 if (eor) { 681 if (n) 682 n->m_flags |= eor; 683 else 684 printf("semi-panic: sbcompress\n"); 685 } 686 } 687 688 /* 689 * Free all mbufs in a sockbuf. 690 * Check that all resources are reclaimed. 691 */ 692 sbflush(sb) 693 register struct sockbuf *sb; 694 { 695 696 if (sb->sb_flags & SB_LOCK) 697 panic("sbflush"); 698 while (sb->sb_mbcnt) 699 sbdrop(sb, (int)sb->sb_cc); 700 if (sb->sb_cc || sb->sb_mb) 701 panic("sbflush 2"); 702 } 703 704 /* 705 * Drop data from (the front of) a sockbuf. 706 */ 707 sbdrop(sb, len) 708 register struct sockbuf *sb; 709 register int len; 710 { 711 register struct mbuf *m, *mn; 712 struct mbuf *next; 713 714 next = (m = sb->sb_mb) ? m->m_nextpkt : 0; 715 while (len > 0) { 716 if (m == 0) { 717 if (next == 0) 718 panic("sbdrop"); 719 m = next; 720 next = m->m_nextpkt; 721 continue; 722 } 723 if (m->m_len > len) { 724 m->m_len -= len; 725 m->m_data += len; 726 sb->sb_cc -= len; 727 break; 728 } 729 len -= m->m_len; 730 sbfree(sb, m); 731 MFREE(m, mn); 732 m = mn; 733 } 734 while (m && m->m_len == 0) { 735 sbfree(sb, m); 736 MFREE(m, mn); 737 m = mn; 738 } 739 if (m) { 740 sb->sb_mb = m; 741 m->m_nextpkt = next; 742 } else 743 sb->sb_mb = next; 744 } 745 746 /* 747 * Drop a record off the front of a sockbuf 748 * and move the next record to the front. 749 */ 750 sbdroprecord(sb) 751 register struct sockbuf *sb; 752 { 753 register struct mbuf *m, *mn; 754 755 m = sb->sb_mb; 756 if (m) { 757 sb->sb_mb = m->m_nextpkt; 758 do { 759 sbfree(sb, m); 760 MFREE(m, mn); 761 } while (m = mn); 762 } 763 } 764
Indexes created Tue Sep 30 20:09:53 GMT 2025