uipc_socket2.c revision 1.8
1/* 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993 3 * The Regents of the University of California. 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 8.1 (Berkeley) 6/10/93 34 * $Id: uipc_socket2.c,v 1.8 1994/05/13 06:01:40 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/mbuf.h> 44#include <sys/protosw.h> 45#include <sys/socket.h> 46#include <sys/socketvar.h> 47 48/* 49 * Primitive routines for operating on sockets and socket buffers 50 */ 51 52/* strings for sleep message: */ 53char netio[] = "netio"; 54char netcon[] = "netcon"; 55char netcls[] = "netcls"; 56 57u_long sb_max = SB_MAX; /* patchable */ 58 59/* 60 * Procedures to manipulate state flags of socket 61 * and do appropriate wakeups. Normal sequence from the 62 * active (originating) side is that soisconnecting() is 63 * called during processing of connect() call, 64 * resulting in an eventual call to soisconnected() if/when the 65 * connection is established. When the connection is torn down 66 * soisdisconnecting() is called during processing of disconnect() call, 67 * and soisdisconnected() is called when the connection to the peer 68 * is totally severed. The semantics of these routines are such that 69 * connectionless protocols can call soisconnected() and soisdisconnected() 70 * only, bypassing the in-progress calls when setting up a ``connection'' 71 * takes no time. 72 * 73 * From the passive side, a socket is created with 74 * two queues of sockets: so_q0 for connections in progress 75 * and so_q for connections already made and awaiting user acceptance. 76 * As a protocol is preparing incoming connections, it creates a socket 77 * structure queued on so_q0 by calling sonewconn(). When the connection 78 * is established, soisconnected() is called, and transfers the 79 * socket structure to so_q, making it available to accept(). 80 * 81 * If a socket is closed with sockets on either 82 * so_q0 or so_q, these sockets are dropped. 83 * 84 * If higher level protocols are implemented in 85 * the kernel, the wakeups done here will sometimes 86 * cause software-interrupt process scheduling. 87 */ 88 89void 90soisconnecting(so) 91 register struct socket *so; 92{ 93 94 so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING); 95 so->so_state |= SS_ISCONNECTING; 96} 97 98void 99soisconnected(so) 100 register struct socket *so; 101{ 102 register struct socket *head = so->so_head; 103 104 so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING|SS_ISCONFIRMING); 105 so->so_state |= SS_ISCONNECTED; 106 if (head && soqremque(so, 0)) { 107 soqinsque(head, so, 1); 108 sorwakeup(head); 109 wakeup((caddr_t)&head->so_timeo); 110 } else { 111 wakeup((caddr_t)&so->so_timeo); 112 sorwakeup(so); 113 sowwakeup(so); 114 } 115} 116 117void 118soisdisconnecting(so) 119 register struct socket *so; 120{ 121 122 so->so_state &= ~SS_ISCONNECTING; 123 so->so_state |= (SS_ISDISCONNECTING|SS_CANTRCVMORE|SS_CANTSENDMORE); 124 wakeup((caddr_t)&so->so_timeo); 125 sowwakeup(so); 126 sorwakeup(so); 127} 128 129void 130soisdisconnected(so) 131 register struct socket *so; 132{ 133 134 so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING); 135 so->so_state |= (SS_CANTRCVMORE|SS_CANTSENDMORE); 136 wakeup((caddr_t)&so->so_timeo); 137 sowwakeup(so); 138 sorwakeup(so); 139} 140 141/* 142 * When an attempt at a new connection is noted on a socket 143 * which accepts connections, sonewconn is called. If the 144 * connection is possible (subject to space constraints, etc.) 145 * then we allocate a new structure, propoerly linked into the 146 * data structure of the original socket, and return this. 147 * Connstatus may be 0, or SO_ISCONFIRMING, or SO_ISCONNECTED. 148 * 149 * Currently, sonewconn() is defined as sonewconn1() in socketvar.h 150 * to catch calls that are missing the (new) second parameter. 151 */ 152struct socket * 153sonewconn1(head, connstatus) 154 register struct socket *head; 155 int connstatus; 156{ 157 register struct socket *so; 158 int soqueue = connstatus ? 1 : 0; 159 160 if (head->so_qlen + head->so_q0len > 3 * head->so_qlimit / 2) 161 return ((struct socket *)0); 162 MALLOC(so, struct socket *, sizeof(*so), M_SOCKET, M_DONTWAIT); 163 if (so == NULL) 164 return ((struct socket *)0); 165 bzero((caddr_t)so, sizeof(*so)); 166 so->so_type = head->so_type; 167 so->so_options = head->so_options &~ SO_ACCEPTCONN; 168 so->so_linger = head->so_linger; 169 so->so_state = head->so_state | SS_NOFDREF; 170 so->so_proto = head->so_proto; 171 so->so_timeo = head->so_timeo; 172 so->so_pgid = head->so_pgid; 173 (void) soreserve(so, head->so_snd.sb_hiwat, head->so_rcv.sb_hiwat); 174 soqinsque(head, so, soqueue); 175 if ((*so->so_proto->pr_usrreq)(so, PRU_ATTACH, 176 (struct mbuf *)0, (struct mbuf *)0, (struct mbuf *)0)) { 177 (void) soqremque(so, soqueue); 178 (void) free((caddr_t)so, M_SOCKET); 179 return ((struct socket *)0); 180 } 181 if (connstatus) { 182 sorwakeup(head); 183 wakeup((caddr_t)&head->so_timeo); 184 so->so_state |= connstatus; 185 } 186 return (so); 187} 188 189void 190soqinsque(head, so, q) 191 register struct socket *head, *so; 192 int q; 193{ 194 195 register struct socket **prev; 196 so->so_head = head; 197 if (q == 0) { 198 head->so_q0len++; 199 so->so_q0 = 0; 200 for (prev = &(head->so_q0); *prev; ) 201 prev = &((*prev)->so_q0); 202 } else { 203 head->so_qlen++; 204 so->so_q = 0; 205 for (prev = &(head->so_q); *prev; ) 206 prev = &((*prev)->so_q); 207 } 208 *prev = so; 209} 210 211int 212soqremque(so, q) 213 register struct socket *so; 214 int q; 215{ 216 register struct socket *head, *prev, *next; 217 218 head = so->so_head; 219 prev = head; 220 for (;;) { 221 next = q ? prev->so_q : prev->so_q0; 222 if (next == so) 223 break; 224 if (next == 0) 225 return (0); 226 prev = next; 227 } 228 if (q == 0) { 229 prev->so_q0 = next->so_q0; 230 head->so_q0len--; 231 } else { 232 prev->so_q = next->so_q; 233 head->so_qlen--; 234 } 235 next->so_q0 = next->so_q = 0; 236 next->so_head = 0; 237 return (1); 238} 239 240/* 241 * Socantsendmore indicates that no more data will be sent on the 242 * socket; it would normally be applied to a socket when the user 243 * informs the system that no more data is to be sent, by the protocol 244 * code (in case PRU_SHUTDOWN). Socantrcvmore indicates that no more data 245 * will be received, and will normally be applied to the socket by a 246 * protocol when it detects that the peer will send no more data. 247 * Data queued for reading in the socket may yet be read. 248 */ 249 250void 251socantsendmore(so) 252 struct socket *so; 253{ 254 255 so->so_state |= SS_CANTSENDMORE; 256 sowwakeup(so); 257} 258 259void 260socantrcvmore(so) 261 struct socket *so; 262{ 263 264 so->so_state |= SS_CANTRCVMORE; 265 sorwakeup(so); 266} 267 268/* 269 * Wait for data to arrive at/drain from a socket buffer. 270 */ 271int 272sbwait(sb) 273 struct sockbuf *sb; 274{ 275 276 sb->sb_flags |= SB_WAIT; 277 return (tsleep((caddr_t)&sb->sb_cc, 278 (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK | PCATCH, netio, 279 sb->sb_timeo)); 280} 281 282/* 283 * Lock a sockbuf already known to be locked; 284 * return any error returned from sleep (EINTR). 285 */ 286int 287sb_lock(sb) 288 register struct sockbuf *sb; 289{ 290 int error; 291 292 while (sb->sb_flags & SB_LOCK) { 293 sb->sb_flags |= SB_WANT; 294 if (error = tsleep((caddr_t)&sb->sb_flags, 295 (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK|PCATCH, 296 netio, 0)) 297 return (error); 298 } 299 sb->sb_flags |= SB_LOCK; 300 return (0); 301} 302 303/* 304 * Wakeup processes waiting on a socket buffer. 305 * Do asynchronous notification via SIGIO 306 * if the socket has the SS_ASYNC flag set. 307 */ 308void 309sowakeup(so, sb) 310 register struct socket *so; 311 register struct sockbuf *sb; 312{ 313 struct proc *p; 314 315 selwakeup(&sb->sb_sel); 316 sb->sb_flags &= ~SB_SEL; 317 if (sb->sb_flags & SB_WAIT) { 318 sb->sb_flags &= ~SB_WAIT; 319 wakeup((caddr_t)&sb->sb_cc); 320 } 321 if (so->so_state & SS_ASYNC) { 322 if (so->so_pgid < 0) 323 gsignal(-so->so_pgid, SIGIO); 324 else if (so->so_pgid > 0 && (p = pfind(so->so_pgid)) != 0) 325 psignal(p, SIGIO); 326 } 327} 328 329/* 330 * Socket buffer (struct sockbuf) utility routines. 331 * 332 * Each socket contains two socket buffers: one for sending data and 333 * one for receiving data. Each buffer contains a queue of mbufs, 334 * information about the number of mbufs and amount of data in the 335 * queue, and other fields allowing select() statements and notification 336 * on data availability to be implemented. 337 * 338 * Data stored in a socket buffer is maintained as a list of records. 339 * Each record is a list of mbufs chained together with the m_next 340 * field. Records are chained together with the m_nextpkt field. The upper 341 * level routine soreceive() expects the following conventions to be 342 * observed when placing information in the receive buffer: 343 * 344 * 1. If the protocol requires each message be preceded by the sender's 345 * name, then a record containing that name must be present before 346 * any associated data (mbuf's must be of type MT_SONAME). 347 * 2. If the protocol supports the exchange of ``access rights'' (really 348 * just additional data associated with the message), and there are 349 * ``rights'' to be received, then a record containing this data 350 * should be present (mbuf's must be of type MT_RIGHTS). 351 * 3. If a name or rights record exists, then it must be followed by 352 * a data record, perhaps of zero length. 353 * 354 * Before using a new socket structure it is first necessary to reserve 355 * buffer space to the socket, by calling sbreserve(). This should commit 356 * some of the available buffer space in the system buffer pool for the 357 * socket (currently, it does nothing but enforce limits). The space 358 * should be released by calling sbrelease() when the socket is destroyed. 359 */ 360 361int 362soreserve(so, sndcc, rcvcc) 363 register struct socket *so; 364 u_long sndcc, rcvcc; 365{ 366 367 if (sbreserve(&so->so_snd, sndcc) == 0) 368 goto bad; 369 if (sbreserve(&so->so_rcv, rcvcc) == 0) 370 goto bad2; 371 if (so->so_rcv.sb_lowat == 0) 372 so->so_rcv.sb_lowat = 1; 373 if (so->so_snd.sb_lowat == 0) 374 so->so_snd.sb_lowat = MCLBYTES; 375 if (so->so_snd.sb_lowat > so->so_snd.sb_hiwat) 376 so->so_snd.sb_lowat = so->so_snd.sb_hiwat; 377 return (0); 378bad2: 379 sbrelease(&so->so_snd); 380bad: 381 return (ENOBUFS); 382} 383 384/* 385 * Allot mbufs to a sockbuf. 386 * Attempt to scale mbmax so that mbcnt doesn't become limiting 387 * if buffering efficiency is near the normal case. 388 */ 389int 390sbreserve(sb, cc) 391 struct sockbuf *sb; 392 u_long cc; 393{ 394 395 if (cc > sb_max * MCLBYTES / (MSIZE + MCLBYTES)) 396 return (0); 397 sb->sb_hiwat = cc; 398 sb->sb_mbmax = min(cc * 2, sb_max); 399 if (sb->sb_lowat > sb->sb_hiwat) 400 sb->sb_lowat = sb->sb_hiwat; 401 return (1); 402} 403 404/* 405 * Free mbufs held by a socket, and reserved mbuf space. 406 */ 407void 408sbrelease(sb) 409 struct sockbuf *sb; 410{ 411 412 sbflush(sb); 413 sb->sb_hiwat = sb->sb_mbmax = 0; 414} 415 416/* 417 * Routines to add and remove 418 * data from an mbuf queue. 419 * 420 * The routines sbappend() or sbappendrecord() are normally called to 421 * append new mbufs to a socket buffer, after checking that adequate 422 * space is available, comparing the function sbspace() with the amount 423 * of data to be added. sbappendrecord() differs from sbappend() in 424 * that data supplied is treated as the beginning of a new record. 425 * To place a sender's address, optional access rights, and data in a 426 * socket receive buffer, sbappendaddr() should be used. To place 427 * access rights and data in a socket receive buffer, sbappendrights() 428 * should be used. In either case, the new data begins a new record. 429 * Note that unlike sbappend() and sbappendrecord(), these routines check 430 * for the caller that there will be enough space to store the data. 431 * Each fails if there is not enough space, or if it cannot find mbufs 432 * to store additional information in. 433 * 434 * Reliable protocols may use the socket send buffer to hold data 435 * awaiting acknowledgement. Data is normally copied from a socket 436 * send buffer in a protocol with m_copy for output to a peer, 437 * and then removing the data from the socket buffer with sbdrop() 438 * or sbdroprecord() when the data is acknowledged by the peer. 439 */ 440 441/* 442 * Append mbuf chain m to the last record in the 443 * socket buffer sb. The additional space associated 444 * the mbuf chain is recorded in sb. Empty mbufs are 445 * discarded and mbufs are compacted where possible. 446 */ 447void 448sbappend(sb, m) 449 struct sockbuf *sb; 450 struct mbuf *m; 451{ 452 register struct mbuf *n; 453 454 if (m == 0) 455 return; 456 if (n = sb->sb_mb) { 457 while (n->m_nextpkt) 458 n = n->m_nextpkt; 459 do { 460 if (n->m_flags & M_EOR) { 461 sbappendrecord(sb, m); /* XXXXXX!!!! */ 462 return; 463 } 464 } while (n->m_next && (n = n->m_next)); 465 } 466 sbcompress(sb, m, n); 467} 468 469#ifdef SOCKBUF_DEBUG 470void 471sbcheck(sb) 472 register struct sockbuf *sb; 473{ 474 register struct mbuf *m; 475 register int len = 0, mbcnt = 0; 476 477 for (m = sb->sb_mb; m; m = m->m_next) { 478 len += m->m_len; 479 mbcnt += MSIZE; 480 if (m->m_flags & M_EXT) 481 mbcnt += m->m_ext.ext_size; 482 if (m->m_nextpkt) 483 panic("sbcheck nextpkt"); 484 } 485 if (len != sb->sb_cc || mbcnt != sb->sb_mbcnt) { 486 printf("cc %d != %d || mbcnt %d != %d\n", len, sb->sb_cc, 487 mbcnt, sb->sb_mbcnt); 488 panic("sbcheck"); 489 } 490} 491#endif 492 493/* 494 * As above, except the mbuf chain 495 * begins a new record. 496 */ 497void 498sbappendrecord(sb, m0) 499 register struct sockbuf *sb; 500 register struct mbuf *m0; 501{ 502 register struct mbuf *m; 503 504 if (m0 == 0) 505 return; 506 if (m = sb->sb_mb) 507 while (m->m_nextpkt) 508 m = m->m_nextpkt; 509 /* 510 * Put the first mbuf on the queue. 511 * Note this permits zero length records. 512 */ 513 sballoc(sb, m0); 514 if (m) 515 m->m_nextpkt = m0; 516 else 517 sb->sb_mb = m0; 518 m = m0->m_next; 519 m0->m_next = 0; 520 if (m && (m0->m_flags & M_EOR)) { 521 m0->m_flags &= ~M_EOR; 522 m->m_flags |= M_EOR; 523 } 524 sbcompress(sb, m, m0); 525} 526 527/* 528 * As above except that OOB data 529 * is inserted at the beginning of the sockbuf, 530 * but after any other OOB data. 531 */ 532void 533sbinsertoob(sb, m0) 534 register struct sockbuf *sb; 535 register struct mbuf *m0; 536{ 537 register struct mbuf *m; 538 register struct mbuf **mp; 539 540 if (m0 == 0) 541 return; 542 for (mp = &sb->sb_mb; m = *mp; mp = &((*mp)->m_nextpkt)) { 543 again: 544 switch (m->m_type) { 545 546 case MT_OOBDATA: 547 continue; /* WANT next train */ 548 549 case MT_CONTROL: 550 if (m = m->m_next) 551 goto again; /* inspect THIS train further */ 552 } 553 break; 554 } 555 /* 556 * Put the first mbuf on the queue. 557 * Note this permits zero length records. 558 */ 559 sballoc(sb, m0); 560 m0->m_nextpkt = *mp; 561 *mp = m0; 562 m = m0->m_next; 563 m0->m_next = 0; 564 if (m && (m0->m_flags & M_EOR)) { 565 m0->m_flags &= ~M_EOR; 566 m->m_flags |= M_EOR; 567 } 568 sbcompress(sb, m, m0); 569} 570 571/* 572 * Append address and data, and optionally, control (ancillary) data 573 * to the receive queue of a socket. If present, 574 * m0 must include a packet header with total length. 575 * Returns 0 if no space in sockbuf or insufficient mbufs. 576 */ 577int 578sbappendaddr(sb, asa, m0, control) 579 register struct sockbuf *sb; 580 struct sockaddr *asa; 581 struct mbuf *m0, *control; 582{ 583 register struct mbuf *m, *n; 584 int space = asa->sa_len; 585 586if (m0 && (m0->m_flags & M_PKTHDR) == 0) 587panic("sbappendaddr"); 588 if (m0) 589 space += m0->m_pkthdr.len; 590 for (n = control; n; n = n->m_next) { 591 space += n->m_len; 592 if (n->m_next == 0) /* keep pointer to last control buf */ 593 break; 594 } 595 if (space > sbspace(sb)) 596 return (0); 597 if (asa->sa_len > MLEN) 598 return (0); 599 MGET(m, M_DONTWAIT, MT_SONAME); 600 if (m == 0) 601 return (0); 602 m->m_len = asa->sa_len; 603 bcopy((caddr_t)asa, mtod(m, caddr_t), asa->sa_len); 604 if (n) 605 n->m_next = m0; /* concatenate data to control */ 606 else 607 control = m0; 608 m->m_next = control; 609 for (n = m; n; n = n->m_next) 610 sballoc(sb, n); 611 if (n = sb->sb_mb) { 612 while (n->m_nextpkt) 613 n = n->m_nextpkt; 614 n->m_nextpkt = m; 615 } else 616 sb->sb_mb = m; 617 return (1); 618} 619 620int 621sbappendcontrol(sb, m0, control) 622 struct sockbuf *sb; 623 struct mbuf *m0, *control; 624{ 625 register struct mbuf *m, *n; 626 int space = 0; 627 628 if (control == 0) 629 panic("sbappendcontrol"); 630 for (m = control; ; m = m->m_next) { 631 space += m->m_len; 632 if (m->m_next == 0) 633 break; 634 } 635 n = m; /* save pointer to last control buffer */ 636 for (m = m0; m; m = m->m_next) 637 space += m->m_len; 638 if (space > sbspace(sb)) 639 return (0); 640 n->m_next = m0; /* concatenate data to control */ 641 for (m = control; m; m = m->m_next) 642 sballoc(sb, m); 643 if (n = sb->sb_mb) { 644 while (n->m_nextpkt) 645 n = n->m_nextpkt; 646 n->m_nextpkt = control; 647 } else 648 sb->sb_mb = control; 649 return (1); 650} 651 652/* 653 * Compress mbuf chain m into the socket 654 * buffer sb following mbuf n. If n 655 * is null, the buffer is presumed empty. 656 */ 657void 658sbcompress(sb, m, n) 659 register struct sockbuf *sb; 660 register struct mbuf *m, *n; 661{ 662 register int eor = 0; 663 register struct mbuf *o; 664 665 while (m) { 666 eor |= m->m_flags & M_EOR; 667 if (m->m_len == 0 && 668 (eor == 0 || 669 (((o = m->m_next) || (o = n)) && 670 o->m_type == m->m_type))) { 671 m = m_free(m); 672 continue; 673 } 674 if (n && (n->m_flags & (M_EXT | M_EOR)) == 0 && 675 (n->m_data + n->m_len + m->m_len) < &n->m_dat[MLEN] && 676 n->m_type == m->m_type) { 677 bcopy(mtod(m, caddr_t), mtod(n, caddr_t) + n->m_len, 678 (unsigned)m->m_len); 679 n->m_len += m->m_len; 680 sb->sb_cc += m->m_len; 681 m = m_free(m); 682 continue; 683 } 684 if (n) 685 n->m_next = m; 686 else 687 sb->sb_mb = m; 688 sballoc(sb, m); 689 n = m; 690 m->m_flags &= ~M_EOR; 691 m = m->m_next; 692 n->m_next = 0; 693 } 694 if (eor) { 695 if (n) 696 n->m_flags |= eor; 697 else 698 printf("semi-panic: sbcompress\n"); 699 } 700} 701 702/* 703 * Free all mbufs in a sockbuf. 704 * Check that all resources are reclaimed. 705 */ 706void 707sbflush(sb) 708 register struct sockbuf *sb; 709{ 710 711 if (sb->sb_flags & SB_LOCK) 712 panic("sbflush"); 713 while (sb->sb_mbcnt) 714 sbdrop(sb, (int)sb->sb_cc); 715 if (sb->sb_cc || sb->sb_mb) 716 panic("sbflush 2"); 717} 718 719/* 720 * Drop data from (the front of) a sockbuf. 721 */ 722void 723sbdrop(sb, len) 724 register struct sockbuf *sb; 725 register int len; 726{ 727 register struct mbuf *m, *mn; 728 struct mbuf *next; 729 730 next = (m = sb->sb_mb) ? m->m_nextpkt : 0; 731 while (len > 0) { 732 if (m == 0) { 733 if (next == 0) 734 panic("sbdrop"); 735 m = next; 736 next = m->m_nextpkt; 737 continue; 738 } 739 if (m->m_len > len) { 740 m->m_len -= len; 741 m->m_data += len; 742 sb->sb_cc -= len; 743 break; 744 } 745 len -= m->m_len; 746 sbfree(sb, m); 747 MFREE(m, mn); 748 m = mn; 749 } 750 while (m && m->m_len == 0) { 751 sbfree(sb, m); 752 MFREE(m, mn); 753 m = mn; 754 } 755 if (m) { 756 sb->sb_mb = m; 757 m->m_nextpkt = next; 758 } else 759 sb->sb_mb = next; 760} 761 762/* 763 * Drop a record off the front of a sockbuf 764 * and move the next record to the front. 765 */ 766void 767sbdroprecord(sb) 768 register struct sockbuf *sb; 769{ 770 register struct mbuf *m, *mn; 771 772 m = sb->sb_mb; 773 if (m) { 774 sb->sb_mb = m->m_nextpkt; 775 do { 776 sbfree(sb, m); 777 MFREE(m, mn); 778 } while (m = mn); 779 } 780} 781