uipc_socket2.c revision 1.10
1/* $NetBSD: uipc_socket2.c,v 1.10 1995/08/16 01:03:19 mycroft Exp $ */ 2 3/* 4 * Copyright (c) 1982, 1986, 1988, 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)uipc_socket2.c 8.1 (Berkeley) 6/10/93 36 */ 37 38#include <sys/param.h> 39#include <sys/systm.h> 40#include <sys/proc.h> 41#include <sys/file.h> 42#include <sys/buf.h> 43#include <sys/malloc.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: */ 54char netio[] = "netio"; 55char netcon[] = "netcon"; 56char netcls[] = "netcls"; 57 58u_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 90void 91soisconnecting(so) 92 register struct socket *so; 93{ 94 95 so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING); 96 so->so_state |= SS_ISCONNECTING; 97} 98 99void 100soisconnected(so) 101 register struct socket *so; 102{ 103 register struct socket *head = so->so_head; 104 105 so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING|SS_ISCONFIRMING); 106 so->so_state |= SS_ISCONNECTED; 107 if (head && soqremque(so, 0)) { 108 soqinsque(head, so, 1); 109 sorwakeup(head); 110 wakeup((caddr_t)&head->so_timeo); 111 } else { 112 wakeup((caddr_t)&so->so_timeo); 113 sorwakeup(so); 114 sowwakeup(so); 115 } 116} 117 118void 119soisdisconnecting(so) 120 register struct socket *so; 121{ 122 123 so->so_state &= ~SS_ISCONNECTING; 124 so->so_state |= (SS_ISDISCONNECTING|SS_CANTRCVMORE|SS_CANTSENDMORE); 125 wakeup((caddr_t)&so->so_timeo); 126 sowwakeup(so); 127 sorwakeup(so); 128} 129 130void 131soisdisconnected(so) 132 register struct socket *so; 133{ 134 135 so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING); 136 so->so_state |= (SS_CANTRCVMORE|SS_CANTSENDMORE); 137 wakeup((caddr_t)&so->so_timeo); 138 sowwakeup(so); 139 sorwakeup(so); 140} 141 142/* 143 * When an attempt at a new connection is noted on a socket 144 * which accepts connections, sonewconn is called. If the 145 * connection is possible (subject to space constraints, etc.) 146 * then we allocate a new structure, propoerly linked into the 147 * data structure of the original socket, and return this. 148 * Connstatus may be 0, or SO_ISCONFIRMING, or SO_ISCONNECTED. 149 * 150 * Currently, sonewconn() is defined as sonewconn1() in socketvar.h 151 * to catch calls that are missing the (new) second parameter. 152 */ 153struct socket * 154sonewconn1(head, connstatus) 155 register struct socket *head; 156 int connstatus; 157{ 158 register struct socket *so; 159 int soqueue = connstatus ? 1 : 0; 160 161 if (head->so_qlen + head->so_q0len > 3 * head->so_qlimit / 2) 162 return ((struct socket *)0); 163 MALLOC(so, struct socket *, sizeof(*so), M_SOCKET, M_DONTWAIT); 164 if (so == NULL) 165 return ((struct socket *)0); 166 bzero((caddr_t)so, sizeof(*so)); 167 so->so_type = head->so_type; 168 so->so_options = head->so_options &~ SO_ACCEPTCONN; 169 so->so_linger = head->so_linger; 170 so->so_state = head->so_state | SS_NOFDREF; 171 so->so_proto = head->so_proto; 172 so->so_timeo = head->so_timeo; 173 so->so_pgid = head->so_pgid; 174 (void) soreserve(so, head->so_snd.sb_hiwat, head->so_rcv.sb_hiwat); 175 soqinsque(head, so, soqueue); 176 if ((*so->so_proto->pr_usrreq)(so, PRU_ATTACH, 177 (struct mbuf *)0, (struct mbuf *)0, (struct mbuf *)0)) { 178 (void) soqremque(so, soqueue); 179 (void) free((caddr_t)so, M_SOCKET); 180 return ((struct socket *)0); 181 } 182 if (connstatus) { 183 sorwakeup(head); 184 wakeup((caddr_t)&head->so_timeo); 185 so->so_state |= connstatus; 186 } 187 return (so); 188} 189 190void 191soqinsque(head, so, q) 192 register struct socket *head, *so; 193 int q; 194{ 195 196 register struct socket **prev; 197 so->so_head = head; 198 if (q == 0) { 199 head->so_q0len++; 200 so->so_q0 = 0; 201 for (prev = &(head->so_q0); *prev; ) 202 prev = &((*prev)->so_q0); 203 } else { 204 head->so_qlen++; 205 so->so_q = 0; 206 for (prev = &(head->so_q); *prev; ) 207 prev = &((*prev)->so_q); 208 } 209 *prev = so; 210} 211 212int 213soqremque(so, q) 214 register struct socket *so; 215 int q; 216{ 217 register struct socket *head, *prev, *next; 218 219 head = so->so_head; 220 prev = head; 221 for (;;) { 222 next = q ? prev->so_q : prev->so_q0; 223 if (next == so) 224 break; 225 if (next == 0) 226 return (0); 227 prev = next; 228 } 229 if (q == 0) { 230 prev->so_q0 = next->so_q0; 231 head->so_q0len--; 232 } else { 233 prev->so_q = next->so_q; 234 head->so_qlen--; 235 } 236 next->so_q0 = next->so_q = 0; 237 next->so_head = 0; 238 return (1); 239} 240 241/* 242 * Socantsendmore indicates that no more data will be sent on the 243 * socket; it would normally be applied to a socket when the user 244 * informs the system that no more data is to be sent, by the protocol 245 * code (in case PRU_SHUTDOWN). Socantrcvmore indicates that no more data 246 * will be received, and will normally be applied to the socket by a 247 * protocol when it detects that the peer will send no more data. 248 * Data queued for reading in the socket may yet be read. 249 */ 250 251void 252socantsendmore(so) 253 struct socket *so; 254{ 255 256 so->so_state |= SS_CANTSENDMORE; 257 sowwakeup(so); 258} 259 260void 261socantrcvmore(so) 262 struct socket *so; 263{ 264 265 so->so_state |= SS_CANTRCVMORE; 266 sorwakeup(so); 267} 268 269/* 270 * Wait for data to arrive at/drain from a socket buffer. 271 */ 272int 273sbwait(sb) 274 struct sockbuf *sb; 275{ 276 277 sb->sb_flags |= SB_WAIT; 278 return (tsleep((caddr_t)&sb->sb_cc, 279 (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK | PCATCH, netio, 280 sb->sb_timeo)); 281} 282 283/* 284 * Lock a sockbuf already known to be locked; 285 * return any error returned from sleep (EINTR). 286 */ 287int 288sb_lock(sb) 289 register struct sockbuf *sb; 290{ 291 int error; 292 293 while (sb->sb_flags & SB_LOCK) { 294 sb->sb_flags |= SB_WANT; 295 if (error = tsleep((caddr_t)&sb->sb_flags, 296 (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK|PCATCH, 297 netio, 0)) 298 return (error); 299 } 300 sb->sb_flags |= SB_LOCK; 301 return (0); 302} 303 304/* 305 * Wakeup processes waiting on a socket buffer. 306 * Do asynchronous notification via SIGIO 307 * if the socket has the SS_ASYNC flag set. 308 */ 309void 310sowakeup(so, sb) 311 register struct socket *so; 312 register struct sockbuf *sb; 313{ 314 struct proc *p; 315 316 selwakeup(&sb->sb_sel); 317 sb->sb_flags &= ~SB_SEL; 318 if (sb->sb_flags & SB_WAIT) { 319 sb->sb_flags &= ~SB_WAIT; 320 wakeup((caddr_t)&sb->sb_cc); 321 } 322 if (so->so_state & SS_ASYNC) { 323 if (so->so_pgid < 0) 324 gsignal(-so->so_pgid, SIGIO); 325 else if (so->so_pgid > 0 && (p = pfind(so->so_pgid)) != 0) 326 psignal(p, SIGIO); 327 } 328} 329 330/* 331 * Socket buffer (struct sockbuf) utility routines. 332 * 333 * Each socket contains two socket buffers: one for sending data and 334 * one for receiving data. Each buffer contains a queue of mbufs, 335 * information about the number of mbufs and amount of data in the 336 * queue, and other fields allowing select() statements and notification 337 * on data availability to be implemented. 338 * 339 * Data stored in a socket buffer is maintained as a list of records. 340 * Each record is a list of mbufs chained together with the m_next 341 * field. Records are chained together with the m_nextpkt field. The upper 342 * level routine soreceive() expects the following conventions to be 343 * observed when placing information in the receive buffer: 344 * 345 * 1. If the protocol requires each message be preceded by the sender's 346 * name, then a record containing that name must be present before 347 * any associated data (mbuf's must be of type MT_SONAME). 348 * 2. If the protocol supports the exchange of ``access rights'' (really 349 * just additional data associated with the message), and there are 350 * ``rights'' to be received, then a record containing this data 351 * should be present (mbuf's must be of type MT_CONTROL). 352 * 3. If a name or rights record exists, then it must be followed by 353 * a data record, perhaps of zero length. 354 * 355 * Before using a new socket structure it is first necessary to reserve 356 * buffer space to the socket, by calling sbreserve(). This should commit 357 * some of the available buffer space in the system buffer pool for the 358 * socket (currently, it does nothing but enforce limits). The space 359 * should be released by calling sbrelease() when the socket is destroyed. 360 */ 361 362int 363soreserve(so, sndcc, rcvcc) 364 register struct socket *so; 365 u_long sndcc, rcvcc; 366{ 367 368 if (sbreserve(&so->so_snd, sndcc) == 0) 369 goto bad; 370 if (sbreserve(&so->so_rcv, rcvcc) == 0) 371 goto bad2; 372 if (so->so_rcv.sb_lowat == 0) 373 so->so_rcv.sb_lowat = 1; 374 if (so->so_snd.sb_lowat == 0) 375 so->so_snd.sb_lowat = MCLBYTES; 376 if (so->so_snd.sb_lowat > so->so_snd.sb_hiwat) 377 so->so_snd.sb_lowat = so->so_snd.sb_hiwat; 378 return (0); 379bad2: 380 sbrelease(&so->so_snd); 381bad: 382 return (ENOBUFS); 383} 384 385/* 386 * Allot mbufs to a sockbuf. 387 * Attempt to scale mbmax so that mbcnt doesn't become limiting 388 * if buffering efficiency is near the normal case. 389 */ 390int 391sbreserve(sb, cc) 392 struct sockbuf *sb; 393 u_long cc; 394{ 395 396 if (cc > sb_max * MCLBYTES / (MSIZE + MCLBYTES)) 397 return (0); 398 sb->sb_hiwat = cc; 399 sb->sb_mbmax = min(cc * 2, sb_max); 400 if (sb->sb_lowat > sb->sb_hiwat) 401 sb->sb_lowat = sb->sb_hiwat; 402 return (1); 403} 404 405/* 406 * Free mbufs held by a socket, and reserved mbuf space. 407 */ 408void 409sbrelease(sb) 410 struct sockbuf *sb; 411{ 412 413 sbflush(sb); 414 sb->sb_hiwat = sb->sb_mbmax = 0; 415} 416 417/* 418 * Routines to add and remove 419 * data from an mbuf queue. 420 * 421 * The routines sbappend() or sbappendrecord() are normally called to 422 * append new mbufs to a socket buffer, after checking that adequate 423 * space is available, comparing the function sbspace() with the amount 424 * of data to be added. sbappendrecord() differs from sbappend() in 425 * that data supplied is treated as the beginning of a new record. 426 * To place a sender's address, optional access rights, and data in a 427 * socket receive buffer, sbappendaddr() should be used. To place 428 * access rights and data in a socket receive buffer, sbappendrights() 429 * should be used. In either case, the new data begins a new record. 430 * Note that unlike sbappend() and sbappendrecord(), these routines check 431 * for the caller that there will be enough space to store the data. 432 * Each fails if there is not enough space, or if it cannot find mbufs 433 * to store additional information in. 434 * 435 * Reliable protocols may use the socket send buffer to hold data 436 * awaiting acknowledgement. Data is normally copied from a socket 437 * send buffer in a protocol with m_copy for output to a peer, 438 * and then removing the data from the socket buffer with sbdrop() 439 * or sbdroprecord() when the data is acknowledged by the peer. 440 */ 441 442/* 443 * Append mbuf chain m to the last record in the 444 * socket buffer sb. The additional space associated 445 * the mbuf chain is recorded in sb. Empty mbufs are 446 * discarded and mbufs are compacted where possible. 447 */ 448void 449sbappend(sb, m) 450 struct sockbuf *sb; 451 struct mbuf *m; 452{ 453 register struct mbuf *n; 454 455 if (m == 0) 456 return; 457 if (n = sb->sb_mb) { 458 while (n->m_nextpkt) 459 n = n->m_nextpkt; 460 do { 461 if (n->m_flags & M_EOR) { 462 sbappendrecord(sb, m); /* XXXXXX!!!! */ 463 return; 464 } 465 } while (n->m_next && (n = n->m_next)); 466 } 467 sbcompress(sb, m, n); 468} 469 470#ifdef SOCKBUF_DEBUG 471void 472sbcheck(sb) 473 register struct sockbuf *sb; 474{ 475 register struct mbuf *m; 476 register int len = 0, mbcnt = 0; 477 478 for (m = sb->sb_mb; m; m = m->m_next) { 479 len += m->m_len; 480 mbcnt += MSIZE; 481 if (m->m_flags & M_EXT) 482 mbcnt += m->m_ext.ext_size; 483 if (m->m_nextpkt) 484 panic("sbcheck nextpkt"); 485 } 486 if (len != sb->sb_cc || mbcnt != sb->sb_mbcnt) { 487 printf("cc %d != %d || mbcnt %d != %d\n", len, sb->sb_cc, 488 mbcnt, sb->sb_mbcnt); 489 panic("sbcheck"); 490 } 491} 492#endif 493 494/* 495 * As above, except the mbuf chain 496 * begins a new record. 497 */ 498void 499sbappendrecord(sb, m0) 500 register struct sockbuf *sb; 501 register struct mbuf *m0; 502{ 503 register struct mbuf *m; 504 505 if (m0 == 0) 506 return; 507 if (m = sb->sb_mb) 508 while (m->m_nextpkt) 509 m = m->m_nextpkt; 510 /* 511 * Put the first mbuf on the queue. 512 * Note this permits zero length records. 513 */ 514 sballoc(sb, m0); 515 if (m) 516 m->m_nextpkt = m0; 517 else 518 sb->sb_mb = m0; 519 m = m0->m_next; 520 m0->m_next = 0; 521 if (m && (m0->m_flags & M_EOR)) { 522 m0->m_flags &= ~M_EOR; 523 m->m_flags |= M_EOR; 524 } 525 sbcompress(sb, m, m0); 526} 527 528/* 529 * As above except that OOB data 530 * is inserted at the beginning of the sockbuf, 531 * but after any other OOB data. 532 */ 533void 534sbinsertoob(sb, m0) 535 register struct sockbuf *sb; 536 register struct mbuf *m0; 537{ 538 register struct mbuf *m; 539 register struct mbuf **mp; 540 541 if (m0 == 0) 542 return; 543 for (mp = &sb->sb_mb; m = *mp; mp = &((*mp)->m_nextpkt)) { 544 again: 545 switch (m->m_type) { 546 547 case MT_OOBDATA: 548 continue; /* WANT next train */ 549 550 case MT_CONTROL: 551 if (m = m->m_next) 552 goto again; /* inspect THIS train further */ 553 } 554 break; 555 } 556 /* 557 * Put the first mbuf on the queue. 558 * Note this permits zero length records. 559 */ 560 sballoc(sb, m0); 561 m0->m_nextpkt = *mp; 562 *mp = m0; 563 m = m0->m_next; 564 m0->m_next = 0; 565 if (m && (m0->m_flags & M_EOR)) { 566 m0->m_flags &= ~M_EOR; 567 m->m_flags |= M_EOR; 568 } 569 sbcompress(sb, m, m0); 570} 571 572/* 573 * Append address and data, and optionally, control (ancillary) data 574 * to the receive queue of a socket. If present, 575 * m0 must include a packet header with total length. 576 * Returns 0 if no space in sockbuf or insufficient mbufs. 577 */ 578int 579sbappendaddr(sb, asa, m0, control) 580 register struct sockbuf *sb; 581 struct sockaddr *asa; 582 struct mbuf *m0, *control; 583{ 584 register struct mbuf *m, *n; 585 int space = asa->sa_len; 586 587if (m0 && (m0->m_flags & M_PKTHDR) == 0) 588panic("sbappendaddr"); 589 if (m0) 590 space += m0->m_pkthdr.len; 591 for (n = control; n; n = n->m_next) { 592 space += n->m_len; 593 if (n->m_next == 0) /* keep pointer to last control buf */ 594 break; 595 } 596 if (space > sbspace(sb)) 597 return (0); 598 if (asa->sa_len > MLEN) 599 return (0); 600 MGET(m, M_DONTWAIT, MT_SONAME); 601 if (m == 0) 602 return (0); 603 m->m_len = asa->sa_len; 604 bcopy((caddr_t)asa, mtod(m, caddr_t), asa->sa_len); 605 if (n) 606 n->m_next = m0; /* concatenate data to control */ 607 else 608 control = m0; 609 m->m_next = control; 610 for (n = m; n; n = n->m_next) 611 sballoc(sb, n); 612 if (n = sb->sb_mb) { 613 while (n->m_nextpkt) 614 n = n->m_nextpkt; 615 n->m_nextpkt = m; 616 } else 617 sb->sb_mb = m; 618 return (1); 619} 620 621int 622sbappendcontrol(sb, m0, control) 623 struct sockbuf *sb; 624 struct mbuf *m0, *control; 625{ 626 register struct mbuf *m, *n; 627 int space = 0; 628 629 if (control == 0) 630 panic("sbappendcontrol"); 631 for (m = control; ; m = m->m_next) { 632 space += m->m_len; 633 if (m->m_next == 0) 634 break; 635 } 636 n = m; /* save pointer to last control buffer */ 637 for (m = m0; m; m = m->m_next) 638 space += m->m_len; 639 if (space > sbspace(sb)) 640 return (0); 641 n->m_next = m0; /* concatenate data to control */ 642 for (m = control; m; m = m->m_next) 643 sballoc(sb, m); 644 if (n = sb->sb_mb) { 645 while (n->m_nextpkt) 646 n = n->m_nextpkt; 647 n->m_nextpkt = control; 648 } else 649 sb->sb_mb = control; 650 return (1); 651} 652 653/* 654 * Compress mbuf chain m into the socket 655 * buffer sb following mbuf n. If n 656 * is null, the buffer is presumed empty. 657 */ 658void 659sbcompress(sb, m, n) 660 register struct sockbuf *sb; 661 register struct mbuf *m, *n; 662{ 663 register int eor = 0; 664 register struct mbuf *o; 665 666 while (m) { 667 eor |= m->m_flags & M_EOR; 668 if (m->m_len == 0 && 669 (eor == 0 || 670 (((o = m->m_next) || (o = n)) && 671 o->m_type == m->m_type))) { 672 m = m_free(m); 673 continue; 674 } 675 if (n && (n->m_flags & (M_EXT | M_EOR)) == 0 && 676 (n->m_data + n->m_len + m->m_len) < &n->m_dat[MLEN] && 677 n->m_type == m->m_type) { 678 bcopy(mtod(m, caddr_t), mtod(n, caddr_t) + n->m_len, 679 (unsigned)m->m_len); 680 n->m_len += m->m_len; 681 sb->sb_cc += m->m_len; 682 m = m_free(m); 683 continue; 684 } 685 if (n) 686 n->m_next = m; 687 else 688 sb->sb_mb = m; 689 sballoc(sb, m); 690 n = m; 691 m->m_flags &= ~M_EOR; 692 m = m->m_next; 693 n->m_next = 0; 694 } 695 if (eor) { 696 if (n) 697 n->m_flags |= eor; 698 else 699 printf("semi-panic: sbcompress\n"); 700 } 701} 702 703/* 704 * Free all mbufs in a sockbuf. 705 * Check that all resources are reclaimed. 706 */ 707void 708sbflush(sb) 709 register struct sockbuf *sb; 710{ 711 712 if (sb->sb_flags & SB_LOCK) 713 panic("sbflush"); 714 while (sb->sb_mbcnt) 715 sbdrop(sb, (int)sb->sb_cc); 716 if (sb->sb_cc || sb->sb_mb) 717 panic("sbflush 2"); 718} 719 720/* 721 * Drop data from (the front of) a sockbuf. 722 */ 723void 724sbdrop(sb, len) 725 register struct sockbuf *sb; 726 register int len; 727{ 728 register struct mbuf *m, *mn; 729 struct mbuf *next; 730 731 next = (m = sb->sb_mb) ? m->m_nextpkt : 0; 732 while (len > 0) { 733 if (m == 0) { 734 if (next == 0) 735 panic("sbdrop"); 736 m = next; 737 next = m->m_nextpkt; 738 continue; 739 } 740 if (m->m_len > len) { 741 m->m_len -= len; 742 m->m_data += len; 743 sb->sb_cc -= len; 744 break; 745 } 746 len -= m->m_len; 747 sbfree(sb, m); 748 MFREE(m, mn); 749 m = mn; 750 } 751 while (m && m->m_len == 0) { 752 sbfree(sb, m); 753 MFREE(m, mn); 754 m = mn; 755 } 756 if (m) { 757 sb->sb_mb = m; 758 m->m_nextpkt = next; 759 } else 760 sb->sb_mb = next; 761} 762 763/* 764 * Drop a record off the front of a sockbuf 765 * and move the next record to the front. 766 */ 767void 768sbdroprecord(sb) 769 register struct sockbuf *sb; 770{ 771 register struct mbuf *m, *mn; 772 773 m = sb->sb_mb; 774 if (m) { 775 sb->sb_mb = m->m_nextpkt; 776 do { 777 sbfree(sb, m); 778 MFREE(m, mn); 779 } while (m = mn); 780 } 781} 782