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 * @(#)uipc_socket2.c 8.1 (Berkeley) 6/10/93 34 * $Id: uipc_socket2.c,v 1.8 1996/01/05 21:41:54 wollman Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/kernel.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/stat.h> 47 #include <sys/socket.h> 48 #include <sys/socketvar.h> 49 #include <sys/signalvar.h> 50 #include <sys/sysctl.h> 51 52 /* 53 * Primitive routines for operating on sockets and socket buffers 54 */ 55 56 u_long sb_max = SB_MAX; /* XXX should be static */ 57 SYSCTL_INT(_kern, KERN_MAXSOCKBUF, maxsockbuf, CTLFLAG_RW, &sb_max, 0, "") 58 59 static u_long sb_efficiency = 8; /* parameter for sbreserve() */ 60 SYSCTL_INT(_kern, OID_AUTO, sockbuf_waste_factor, CTLFLAG_RW, &sb_efficiency, 61 0, ""); 62 63 /* 64 * Procedures to manipulate state flags of socket 65 * and do appropriate wakeups. Normal sequence from the 66 * active (originating) side is that soisconnecting() is 67 * called during processing of connect() call, 68 * resulting in an eventual call to soisconnected() if/when the 69 * connection is established. When the connection is torn down 70 * soisdisconnecting() is called during processing of disconnect() call, 71 * and soisdisconnected() is called when the connection to the peer 72 * is totally severed. The semantics of these routines are such that 73 * connectionless protocols can call soisconnected() and soisdisconnected() 74 * only, bypassing the in-progress calls when setting up a ``connection'' 75 * takes no time. 76 * 77 * From the passive side, a socket is created with 78 * two queues of sockets: so_q0 for connections in progress 79 * and so_q for connections already made and awaiting user acceptance. 80 * As a protocol is preparing incoming connections, it creates a socket 81 * structure queued on so_q0 by calling sonewconn(). When the connection 82 * is established, soisconnected() is called, and transfers the 83 * socket structure to so_q, making it available to accept(). 84 * 85 * If a socket is closed with sockets on either 86 * so_q0 or so_q, these sockets are dropped. 87 * 88 * If higher level protocols are implemented in 89 * the kernel, the wakeups done here will sometimes 90 * cause software-interrupt process scheduling. 91 */ 92 93 void 94 soisconnecting(so) 95 register struct socket *so; 96 { 97 98 so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING); 99 so->so_state |= SS_ISCONNECTING; 100 } 101 102 void 103 soisconnected(so) 104 register struct socket *so; 105 { 106 register struct socket *head = so->so_head; 107 108 so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING|SS_ISCONFIRMING); 109 so->so_state |= SS_ISCONNECTED; 110 if (head && (so->so_state & SS_INCOMP)) { 111 TAILQ_REMOVE(&head->so_incomp, so, so_list); 112 so->so_state &= ~SS_INCOMP; 113 TAILQ_INSERT_TAIL(&head->so_comp, so, so_list); 114 so->so_state |= SS_COMP; 115 sorwakeup(head); 116 wakeup((caddr_t)&head->so_timeo); 117 } else { 118 wakeup((caddr_t)&so->so_timeo); 119 sorwakeup(so); 120 sowwakeup(so); 121 } 122 } 123 124 void 125 soisdisconnecting(so) 126 register struct socket *so; 127 { 128 129 so->so_state &= ~SS_ISCONNECTING; 130 so->so_state |= (SS_ISDISCONNECTING|SS_CANTRCVMORE|SS_CANTSENDMORE); 131 wakeup((caddr_t)&so->so_timeo); 132 sowwakeup(so); 133 sorwakeup(so); 134 } 135 136 void 137 soisdisconnected(so) 138 register struct socket *so; 139 { 140 141 so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING); 142 so->so_state |= (SS_CANTRCVMORE|SS_CANTSENDMORE); 143 wakeup((caddr_t)&so->so_timeo); 144 sowwakeup(so); 145 sorwakeup(so); 146 } 147 148 /* 149 * When an attempt at a new connection is noted on a socket 150 * which accepts connections, sonewconn is called. If the 151 * connection is possible (subject to space constraints, etc.) 152 * then we allocate a new structure, propoerly linked into the 153 * data structure of the original socket, and return this. 154 * Connstatus may be 0, or SO_ISCONFIRMING, or SO_ISCONNECTED. 155 * 156 * Currently, sonewconn() is defined as sonewconn1() in socketvar.h 157 * to catch calls that are missing the (new) second parameter. 158 */ 159 struct socket * 160 sonewconn1(head, connstatus) 161 register struct socket *head; 162 int connstatus; 163 { 164 register struct socket *so; 165 int soqueue = connstatus ? 1 : 0; 166 167 if (head->so_qlen > 3 * head->so_qlimit / 2) 168 return ((struct socket *)0); 169 MALLOC(so, struct socket *, sizeof(*so), M_SOCKET, M_DONTWAIT); 170 if (so == NULL) 171 return ((struct socket *)0); 172 bzero((caddr_t)so, sizeof(*so)); 173 so->so_head = head; 174 so->so_type = head->so_type; 175 so->so_options = head->so_options &~ SO_ACCEPTCONN; 176 so->so_linger = head->so_linger; 177 so->so_state = head->so_state | SS_NOFDREF; 178 so->so_proto = head->so_proto; 179 so->so_timeo = head->so_timeo; 180 so->so_pgid = head->so_pgid; 181 (void) soreserve(so, head->so_snd.sb_hiwat, head->so_rcv.sb_hiwat); 182 if (connstatus) { 183 TAILQ_INSERT_TAIL(&head->so_comp, so, so_list); 184 so->so_state |= SS_COMP; 185 } else { 186 TAILQ_INSERT_TAIL(&head->so_incomp, so, so_list); 187 so->so_state |= SS_INCOMP; 188 } 189 head->so_qlen++; 190 if ((*so->so_proto->pr_usrreq)(so, PRU_ATTACH, 191 (struct mbuf *)0, (struct mbuf *)0, (struct mbuf *)0)) { 192 if (so->so_state & SS_COMP) { 193 TAILQ_REMOVE(&head->so_comp, so, so_list); 194 } else { 195 TAILQ_REMOVE(&head->so_incomp, so, so_list); 196 } 197 head->so_qlen--; 198 (void) free((caddr_t)so, M_SOCKET); 199 return ((struct socket *)0); 200 } 201 if (connstatus) { 202 sorwakeup(head); 203 wakeup((caddr_t)&head->so_timeo); 204 so->so_state |= connstatus; 205 } 206 return (so); 207 } 208 209 /* 210 * Socantsendmore indicates that no more data will be sent on the 211 * socket; it would normally be applied to a socket when the user 212 * informs the system that no more data is to be sent, by the protocol 213 * code (in case PRU_SHUTDOWN). Socantrcvmore indicates that no more data 214 * will be received, and will normally be applied to the socket by a 215 * protocol when it detects that the peer will send no more data. 216 * Data queued for reading in the socket may yet be read. 217 */ 218 219 void 220 socantsendmore(so) 221 struct socket *so; 222 { 223 224 so->so_state |= SS_CANTSENDMORE; 225 sowwakeup(so); 226 } 227 228 void 229 socantrcvmore(so) 230 struct socket *so; 231 { 232 233 so->so_state |= SS_CANTRCVMORE; 234 sorwakeup(so); 235 } 236 237 /* 238 * Wait for data to arrive at/drain from a socket buffer. 239 */ 240 int 241 sbwait(sb) 242 struct sockbuf *sb; 243 { 244 245 sb->sb_flags |= SB_WAIT; 246 return (tsleep((caddr_t)&sb->sb_cc, 247 (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK | PCATCH, "sbwait", 248 sb->sb_timeo)); 249 } 250 251 /* 252 * Lock a sockbuf already known to be locked; 253 * return any error returned from sleep (EINTR). 254 */ 255 int 256 sb_lock(sb) 257 register struct sockbuf *sb; 258 { 259 int error; 260 261 while (sb->sb_flags & SB_LOCK) { 262 sb->sb_flags |= SB_WANT; 263 error = tsleep((caddr_t)&sb->sb_flags, 264 (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK|PCATCH, 265 "sblock", 0); 266 if (error) 267 return (error); 268 } 269 sb->sb_flags |= SB_LOCK; 270 return (0); 271 } 272 273 /* 274 * Wakeup processes waiting on a socket buffer. 275 * Do asynchronous notification via SIGIO 276 * if the socket has the SS_ASYNC flag set. 277 */ 278 void 279 sowakeup(so, sb) 280 register struct socket *so; 281 register struct sockbuf *sb; 282 { 283 struct proc *p; 284 285 selwakeup(&sb->sb_sel); 286 sb->sb_flags &= ~SB_SEL; 287 if (sb->sb_flags & SB_WAIT) { 288 sb->sb_flags &= ~SB_WAIT; 289 wakeup((caddr_t)&sb->sb_cc); 290 } 291 if (so->so_state & SS_ASYNC) { 292 if (so->so_pgid < 0) 293 gsignal(-so->so_pgid, SIGIO); 294 else if (so->so_pgid > 0 && (p = pfind(so->so_pgid)) != 0) 295 psignal(p, SIGIO); 296 } 297 } 298 299 /* 300 * Socket buffer (struct sockbuf) utility routines. 301 * 302 * Each socket contains two socket buffers: one for sending data and 303 * one for receiving data. Each buffer contains a queue of mbufs, 304 * information about the number of mbufs and amount of data in the 305 * queue, and other fields allowing select() statements and notification 306 * on data availability to be implemented. 307 * 308 * Data stored in a socket buffer is maintained as a list of records. 309 * Each record is a list of mbufs chained together with the m_next 310 * field. Records are chained together with the m_nextpkt field. The upper 311 * level routine soreceive() expects the following conventions to be 312 * observed when placing information in the receive buffer: 313 * 314 * 1. If the protocol requires each message be preceded by the sender's 315 * name, then a record containing that name must be present before 316 * any associated data (mbuf's must be of type MT_SONAME). 317 * 2. If the protocol supports the exchange of ``access rights'' (really 318 * just additional data associated with the message), and there are 319 * ``rights'' to be received, then a record containing this data 320 * should be present (mbuf's must be of type MT_RIGHTS). 321 * 3. If a name or rights record exists, then it must be followed by 322 * a data record, perhaps of zero length. 323 * 324 * Before using a new socket structure it is first necessary to reserve 325 * buffer space to the socket, by calling sbreserve(). This should commit 326 * some of the available buffer space in the system buffer pool for the 327 * socket (currently, it does nothing but enforce limits). The space 328 * should be released by calling sbrelease() when the socket is destroyed. 329 */ 330 331 int 332 soreserve(so, sndcc, rcvcc) 333 register struct socket *so; 334 u_long sndcc, rcvcc; 335 { 336 337 if (sbreserve(&so->so_snd, sndcc) == 0) 338 goto bad; 339 if (sbreserve(&so->so_rcv, rcvcc) == 0) 340 goto bad2; 341 if (so->so_rcv.sb_lowat == 0) 342 so->so_rcv.sb_lowat = 1; 343 if (so->so_snd.sb_lowat == 0) 344 so->so_snd.sb_lowat = MCLBYTES; 345 if (so->so_snd.sb_lowat > so->so_snd.sb_hiwat) 346 so->so_snd.sb_lowat = so->so_snd.sb_hiwat; 347 return (0); 348 bad2: 349 sbrelease(&so->so_snd); 350 bad: 351 return (ENOBUFS); 352 } 353 354 /* 355 * Allot mbufs to a sockbuf. 356 * Attempt to scale mbmax so that mbcnt doesn't become limiting 357 * if buffering efficiency is near the normal case. 358 */ 359 int 360 sbreserve(sb, cc) 361 struct sockbuf *sb; 362 u_long cc; 363 { 364 365 if (cc > sb_max * MCLBYTES / (MSIZE + MCLBYTES)) 366 return (0); 367 sb->sb_hiwat = cc; 368 sb->sb_mbmax = min(cc * sb_efficiency, sb_max); 369 if (sb->sb_lowat > sb->sb_hiwat) 370 sb->sb_lowat = sb->sb_hiwat; 371 return (1); 372 } 373 374 /* 375 * Free mbufs held by a socket, and reserved mbuf space. 376 */ 377 void 378 sbrelease(sb) 379 struct sockbuf *sb; 380 { 381 382 sbflush(sb); 383 sb->sb_hiwat = sb->sb_mbmax = 0; 384 } 385 386 /* 387 * Routines to add and remove 388 * data from an mbuf queue. 389 * 390 * The routines sbappend() or sbappendrecord() are normally called to 391 * append new mbufs to a socket buffer, after checking that adequate 392 * space is available, comparing the function sbspace() with the amount 393 * of data to be added. sbappendrecord() differs from sbappend() in 394 * that data supplied is treated as the beginning of a new record. 395 * To place a sender's address, optional access rights, and data in a 396 * socket receive buffer, sbappendaddr() should be used. To place 397 * access rights and data in a socket receive buffer, sbappendrights() 398 * should be used. In either case, the new data begins a new record. 399 * Note that unlike sbappend() and sbappendrecord(), these routines check 400 * for the caller that there will be enough space to store the data. 401 * Each fails if there is not enough space, or if it cannot find mbufs 402 * to store additional information in. 403 * 404 * Reliable protocols may use the socket send buffer to hold data 405 * awaiting acknowledgement. Data is normally copied from a socket 406 * send buffer in a protocol with m_copy for output to a peer, 407 * and then removing the data from the socket buffer with sbdrop() 408 * or sbdroprecord() when the data is acknowledged by the peer. 409 */ 410 411 /* 412 * Append mbuf chain m to the last record in the 413 * socket buffer sb. The additional space associated 414 * the mbuf chain is recorded in sb. Empty mbufs are 415 * discarded and mbufs are compacted where possible. 416 */ 417 void 418 sbappend(sb, m) 419 struct sockbuf *sb; 420 struct mbuf *m; 421 { 422 register struct mbuf *n; 423 424 if (m == 0) 425 return; 426 n = sb->sb_mb; 427 if (n) { 428 while (n->m_nextpkt) 429 n = n->m_nextpkt; 430 do { 431 if (n->m_flags & M_EOR) { 432 sbappendrecord(sb, m); /* XXXXXX!!!! */ 433 return; 434 } 435 } while (n->m_next && (n = n->m_next)); 436 } 437 sbcompress(sb, m, n); 438 } 439 440 #ifdef SOCKBUF_DEBUG 441 void 442 sbcheck(sb) 443 register struct sockbuf *sb; 444 { 445 register struct mbuf *m; 446 register int len = 0, mbcnt = 0; 447 448 for (m = sb->sb_mb; m; m = m->m_next) { 449 len += m->m_len; 450 mbcnt += MSIZE; 451 if (m->m_flags & M_EXT) 452 mbcnt += m->m_ext.ext_size; 453 if (m->m_nextpkt) 454 panic("sbcheck nextpkt"); 455 } 456 if (len != sb->sb_cc || mbcnt != sb->sb_mbcnt) { 457 printf("cc %d != %d || mbcnt %d != %d\n", len, sb->sb_cc, 458 mbcnt, sb->sb_mbcnt); 459 panic("sbcheck"); 460 } 461 } 462 #endif 463 464 /* 465 * As above, except the mbuf chain 466 * begins a new record. 467 */ 468 void 469 sbappendrecord(sb, m0) 470 register struct sockbuf *sb; 471 register struct mbuf *m0; 472 { 473 register struct mbuf *m; 474 475 if (m0 == 0) 476 return; 477 m = sb->sb_mb; 478 if (m) 479 while (m->m_nextpkt) 480 m = m->m_nextpkt; 481 /* 482 * Put the first mbuf on the queue. 483 * Note this permits zero length records. 484 */ 485 sballoc(sb, m0); 486 if (m) 487 m->m_nextpkt = m0; 488 else 489 sb->sb_mb = m0; 490 m = m0->m_next; 491 m0->m_next = 0; 492 if (m && (m0->m_flags & M_EOR)) { 493 m0->m_flags &= ~M_EOR; 494 m->m_flags |= M_EOR; 495 } 496 sbcompress(sb, m, m0); 497 } 498 499 /* 500 * As above except that OOB data 501 * is inserted at the beginning of the sockbuf, 502 * but after any other OOB data. 503 */ 504 void 505 sbinsertoob(sb, m0) 506 register struct sockbuf *sb; 507 register struct mbuf *m0; 508 { 509 register struct mbuf *m; 510 register struct mbuf **mp; 511 512 if (m0 == 0) 513 return; 514 for (mp = &sb->sb_mb; *mp ; mp = &((*mp)->m_nextpkt)) { 515 m = *mp; 516 again: 517 switch (m->m_type) { 518 519 case MT_OOBDATA: 520 continue; /* WANT next train */ 521 522 case MT_CONTROL: 523 m = m->m_next; 524 if (m) 525 goto again; /* inspect THIS train further */ 526 } 527 break; 528 } 529 /* 530 * Put the first mbuf on the queue. 531 * Note this permits zero length records. 532 */ 533 sballoc(sb, m0); 534 m0->m_nextpkt = *mp; 535 *mp = m0; 536 m = m0->m_next; 537 m0->m_next = 0; 538 if (m && (m0->m_flags & M_EOR)) { 539 m0->m_flags &= ~M_EOR; 540 m->m_flags |= M_EOR; 541 } 542 sbcompress(sb, m, m0); 543 } 544 545 /* 546 * Append address and data, and optionally, control (ancillary) data 547 * to the receive queue of a socket. If present, 548 * m0 must include a packet header with total length. 549 * Returns 0 if no space in sockbuf or insufficient mbufs. 550 */ 551 int 552 sbappendaddr(sb, asa, m0, control) 553 register struct sockbuf *sb; 554 struct sockaddr *asa; 555 struct mbuf *m0, *control; 556 { 557 register struct mbuf *m, *n; 558 int space = asa->sa_len; 559 560 if (m0 && (m0->m_flags & M_PKTHDR) == 0) 561 panic("sbappendaddr"); 562 if (m0) 563 space += m0->m_pkthdr.len; 564 for (n = control; n; n = n->m_next) { 565 space += n->m_len; 566 if (n->m_next == 0) /* keep pointer to last control buf */ 567 break; 568 } 569 if (space > sbspace(sb)) 570 return (0); 571 if (asa->sa_len > MLEN) 572 return (0); 573 MGET(m, M_DONTWAIT, MT_SONAME); 574 if (m == 0) 575 return (0); 576 m->m_len = asa->sa_len; 577 bcopy((caddr_t)asa, mtod(m, caddr_t), asa->sa_len); 578 if (n) 579 n->m_next = m0; /* concatenate data to control */ 580 else 581 control = m0; 582 m->m_next = control; 583 for (n = m; n; n = n->m_next) 584 sballoc(sb, n); 585 n = sb->sb_mb; 586 if (n) { 587 while (n->m_nextpkt) 588 n = n->m_nextpkt; 589 n->m_nextpkt = m; 590 } else 591 sb->sb_mb = m; 592 return (1); 593 } 594 595 int 596 sbappendcontrol(sb, m0, control) 597 struct sockbuf *sb; 598 struct mbuf *control, *m0; 599 { 600 register struct mbuf *m, *n; 601 int space = 0; 602 603 if (control == 0) 604 panic("sbappendcontrol"); 605 for (m = control; ; m = m->m_next) { 606 space += m->m_len; 607 if (m->m_next == 0) 608 break; 609 } 610 n = m; /* save pointer to last control buffer */ 611 for (m = m0; m; m = m->m_next) 612 space += m->m_len; 613 if (space > sbspace(sb)) 614 return (0); 615 n->m_next = m0; /* concatenate data to control */ 616 for (m = control; m; m = m->m_next) 617 sballoc(sb, m); 618 n = sb->sb_mb; 619 if (n) { 620 while (n->m_nextpkt) 621 n = n->m_nextpkt; 622 n->m_nextpkt = control; 623 } else 624 sb->sb_mb = control; 625 return (1); 626 } 627 628 /* 629 * Compress mbuf chain m into the socket 630 * buffer sb following mbuf n. If n 631 * is null, the buffer is presumed empty. 632 */ 633 void 634 sbcompress(sb, m, n) 635 register struct sockbuf *sb; 636 register struct mbuf *m, *n; 637 { 638 register int eor = 0; 639 register struct mbuf *o; 640 641 while (m) { 642 eor |= m->m_flags & M_EOR; 643 if (m->m_len == 0 && 644 (eor == 0 || 645 (((o = m->m_next) || (o = n)) && 646 o->m_type == m->m_type))) { 647 m = m_free(m); 648 continue; 649 } 650 if (n && (n->m_flags & (M_EXT | M_EOR)) == 0 && 651 (n->m_data + n->m_len + m->m_len) < &n->m_dat[MLEN] && 652 n->m_type == m->m_type) { 653 bcopy(mtod(m, caddr_t), mtod(n, caddr_t) + n->m_len, 654 (unsigned)m->m_len); 655 n->m_len += m->m_len; 656 sb->sb_cc += m->m_len; 657 m = m_free(m); 658 continue; 659 } 660 if (n) 661 n->m_next = m; 662 else 663 sb->sb_mb = m; 664 sballoc(sb, m); 665 n = m; 666 m->m_flags &= ~M_EOR; 667 m = m->m_next; 668 n->m_next = 0; 669 } 670 if (eor) { 671 if (n) 672 n->m_flags |= eor; 673 else 674 printf("semi-panic: sbcompress\n"); 675 } 676 } 677 678 /* 679 * Free all mbufs in a sockbuf. 680 * Check that all resources are reclaimed. 681 */ 682 void 683 sbflush(sb) 684 register struct sockbuf *sb; 685 { 686 687 if (sb->sb_flags & SB_LOCK) 688 panic("sbflush"); 689 while (sb->sb_mbcnt) 690 sbdrop(sb, (int)sb->sb_cc); 691 if (sb->sb_cc || sb->sb_mb) 692 panic("sbflush 2"); 693 } 694 695 /* 696 * Drop data from (the front of) a sockbuf. 697 */ 698 void 699 sbdrop(sb, len) 700 register struct sockbuf *sb; 701 register int len; 702 { 703 register struct mbuf *m, *mn; 704 struct mbuf *next; 705 706 next = (m = sb->sb_mb) ? m->m_nextpkt : 0; 707 while (len > 0) { 708 if (m == 0) { 709 if (next == 0) 710 panic("sbdrop"); 711 m = next; 712 next = m->m_nextpkt; 713 continue; 714 } 715 if (m->m_len > len) { 716 m->m_len -= len; 717 m->m_data += len; 718 sb->sb_cc -= len; 719 break; 720 } 721 len -= m->m_len; 722 sbfree(sb, m); 723 MFREE(m, mn); 724 m = mn; 725 } 726 while (m && m->m_len == 0) { 727 sbfree(sb, m); 728 MFREE(m, mn); 729 m = mn; 730 } 731 if (m) { 732 sb->sb_mb = m; 733 m->m_nextpkt = next; 734 } else 735 sb->sb_mb = next; 736 } 737 738 /* 739 * Drop a record off the front of a sockbuf 740 * and move the next record to the front. 741 */ 742 void 743 sbdroprecord(sb) 744 register struct sockbuf *sb; 745 { 746 register struct mbuf *m, *mn; 747 748 m = sb->sb_mb; 749 if (m) { 750 sb->sb_mb = m->m_nextpkt; 751 do { 752 sbfree(sb, m); 753 MFREE(m, mn); 754 m = mn; 755 } while (m); 756 } 757 } 758