/* $OpenBSD: uipc_socket2.c,v 1.44 2008/05/23 15:51:12 thib Exp $ */ /* $NetBSD: uipc_socket2.c,v 1.11 1996/02/04 02:17:55 christos Exp $ */ /* * Copyright (c) 1982, 1986, 1988, 1990, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)uipc_socket2.c 8.1 (Berkeley) 6/10/93 */ #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Primitive routines for operating on sockets and socket buffers */ /* strings for sleep message: */ const char netcon[] = "netcon"; const char netcls[] = "netcls"; const char netio[] = "netio"; const char netlck[] = "netlck"; u_long sb_max = SB_MAX; /* patchable */ extern struct pool mclpool; /* * Procedures to manipulate state flags of socket * and do appropriate wakeups. Normal sequence from the * active (originating) side is that soisconnecting() is * called during processing of connect() call, * resulting in an eventual call to soisconnected() if/when the * connection is established. When the connection is torn down * soisdisconnecting() is called during processing of disconnect() call, * and soisdisconnected() is called when the connection to the peer * is totally severed. The semantics of these routines are such that * connectionless protocols can call soisconnected() and soisdisconnected() * only, bypassing the in-progress calls when setting up a ``connection'' * takes no time. * * From the passive side, a socket is created with * two queues of sockets: so_q0 for connections in progress * and so_q for connections already made and awaiting user acceptance. * As a protocol is preparing incoming connections, it creates a socket * structure queued on so_q0 by calling sonewconn(). When the connection * is established, soisconnected() is called, and transfers the * socket structure to so_q, making it available to accept(). * * If a socket is closed with sockets on either * so_q0 or so_q, these sockets are dropped. * * If higher level protocols are implemented in * the kernel, the wakeups done here will sometimes * cause software-interrupt process scheduling. */ void soisconnecting(struct socket *so) { so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING); so->so_state |= SS_ISCONNECTING; } void soisconnected(struct socket *so) { struct socket *head = so->so_head; so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING|SS_ISCONFIRMING); so->so_state |= SS_ISCONNECTED; if (head && soqremque(so, 0)) { soqinsque(head, so, 1); sorwakeup(head); wakeup_one(&head->so_timeo); } else { wakeup(&so->so_timeo); sorwakeup(so); sowwakeup(so); } } void soisdisconnecting(struct socket *so) { so->so_state &= ~SS_ISCONNECTING; so->so_state |= (SS_ISDISCONNECTING|SS_CANTRCVMORE|SS_CANTSENDMORE); wakeup(&so->so_timeo); sowwakeup(so); sorwakeup(so); } void soisdisconnected(struct socket *so) { so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING); so->so_state |= (SS_CANTRCVMORE|SS_CANTSENDMORE|SS_ISDISCONNECTED); wakeup(&so->so_timeo); sowwakeup(so); sorwakeup(so); } /* * When an attempt at a new connection is noted on a socket * which accepts connections, sonewconn is called. If the * connection is possible (subject to space constraints, etc.) * then we allocate a new structure, properly linked into the * data structure of the original socket, and return this. * Connstatus may be 0, or SS_ISCONFIRMING, or SS_ISCONNECTED. * * Must be called at splsoftnet() */ struct socket * sonewconn(struct socket *head, int connstatus) { struct socket *so; int soqueue = connstatus ? 1 : 0; extern u_long unpst_sendspace, unpst_recvspace; u_long snd_sb_hiwat, rcv_sb_hiwat; splassert(IPL_SOFTNET); if (mclpool.pr_nout > mclpool.pr_hardlimit * 95 / 100) return ((struct socket *)0); if (head->so_qlen + head->so_q0len > head->so_qlimit * 3) return ((struct socket *)0); so = pool_get(&socket_pool, PR_NOWAIT); if (so == NULL) return ((struct socket *)0); bzero(so, sizeof(*so)); so->so_type = head->so_type; so->so_options = head->so_options &~ SO_ACCEPTCONN; so->so_linger = head->so_linger; so->so_state = head->so_state | SS_NOFDREF; so->so_proto = head->so_proto; so->so_timeo = head->so_timeo; so->so_pgid = head->so_pgid; so->so_euid = head->so_euid; so->so_ruid = head->so_ruid; so->so_egid = head->so_egid; so->so_rgid = head->so_rgid; so->so_cpid = head->so_cpid; so->so_siguid = head->so_siguid; so->so_sigeuid = head->so_sigeuid; /* * If we are tight on mbuf clusters, create the new socket * with the minimum. Sorry, you lose. */ snd_sb_hiwat = head->so_snd.sb_hiwat; if (sbcheckreserve(snd_sb_hiwat, unpst_sendspace)) snd_sb_hiwat = unpst_sendspace; /* and udp? */ rcv_sb_hiwat = head->so_rcv.sb_hiwat; if (sbcheckreserve(rcv_sb_hiwat, unpst_recvspace)) rcv_sb_hiwat = unpst_recvspace; /* and udp? */ (void) soreserve(so, snd_sb_hiwat, rcv_sb_hiwat); soqinsque(head, so, soqueue); if ((*so->so_proto->pr_usrreq)(so, PRU_ATTACH, NULL, NULL, NULL, curproc)) { (void) soqremque(so, soqueue); pool_put(&socket_pool, so); return ((struct socket *)0); } if (connstatus) { sorwakeup(head); wakeup(&head->so_timeo); so->so_state |= connstatus; } return (so); } void soqinsque(struct socket *head, struct socket *so, int q) { #ifdef DIAGNOSTIC if (so->so_onq != NULL) panic("soqinsque"); #endif so->so_head = head; if (q == 0) { head->so_q0len++; so->so_onq = &head->so_q0; } else { head->so_qlen++; so->so_onq = &head->so_q; } TAILQ_INSERT_TAIL(so->so_onq, so, so_qe); } int soqremque(struct socket *so, int q) { struct socket *head; head = so->so_head; if (q == 0) { if (so->so_onq != &head->so_q0) return (0); head->so_q0len--; } else { if (so->so_onq != &head->so_q) return (0); head->so_qlen--; } TAILQ_REMOVE(so->so_onq, so, so_qe); so->so_onq = NULL; so->so_head = NULL; return (1); } /* * Socantsendmore indicates that no more data will be sent on the * socket; it would normally be applied to a socket when the user * informs the system that no more data is to be sent, by the protocol * code (in case PRU_SHUTDOWN). Socantrcvmore indicates that no more data * will be received, and will normally be applied to the socket by a * protocol when it detects that the peer will send no more data. * Data queued for reading in the socket may yet be read. */ void socantsendmore(struct socket *so) { so->so_state |= SS_CANTSENDMORE; sowwakeup(so); } void socantrcvmore(struct socket *so) { so->so_state |= SS_CANTRCVMORE; sorwakeup(so); } /* * Wait for data to arrive at/drain from a socket buffer. */ int sbwait(struct sockbuf *sb) { sb->sb_flags |= SB_WAIT; return (tsleep(&sb->sb_cc, (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK | PCATCH, netio, sb->sb_timeo)); } /* * Lock a sockbuf already known to be locked; * return any error returned from sleep (EINTR). */ int sb_lock(struct sockbuf *sb) { int error; while (sb->sb_flags & SB_LOCK) { sb->sb_flags |= SB_WANT; error = tsleep(&sb->sb_flags, (sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK|PCATCH, netlck, 0); if (error) return (error); } sb->sb_flags |= SB_LOCK; return (0); } /* * Wakeup processes waiting on a socket buffer. * Do asynchronous notification via SIGIO * if the socket has the SS_ASYNC flag set. */ void sowakeup(struct socket *so, struct sockbuf *sb) { selwakeup(&sb->sb_sel); sb->sb_flags &= ~SB_SEL; if (sb->sb_flags & SB_WAIT) { sb->sb_flags &= ~SB_WAIT; wakeup(&sb->sb_cc); } if (so->so_state & SS_ASYNC) csignal(so->so_pgid, SIGIO, so->so_siguid, so->so_sigeuid); KNOTE(&sb->sb_sel.si_note, 0); } /* * Socket buffer (struct sockbuf) utility routines. * * Each socket contains two socket buffers: one for sending data and * one for receiving data. Each buffer contains a queue of mbufs, * information about the number of mbufs and amount of data in the * queue, and other fields allowing select() statements and notification * on data availability to be implemented. * * Data stored in a socket buffer is maintained as a list of records. * Each record is a list of mbufs chained together with the m_next * field. Records are chained together with the m_nextpkt field. The upper * level routine soreceive() expects the following conventions to be * observed when placing information in the receive buffer: * * 1. If the protocol requires each message be preceded by the sender's * name, then a record containing that name must be present before * any associated data (mbuf's must be of type MT_SONAME). * 2. If the protocol supports the exchange of ``access rights'' (really * just additional data associated with the message), and there are * ``rights'' to be received, then a record containing this data * should be present (mbuf's must be of type MT_CONTROL). * 3. If a name or rights record exists, then it must be followed by * a data record, perhaps of zero length. * * Before using a new socket structure it is first necessary to reserve * buffer space to the socket, by calling sbreserve(). This should commit * some of the available buffer space in the system buffer pool for the * socket (currently, it does nothing but enforce limits). The space * should be released by calling sbrelease() when the socket is destroyed. */ int soreserve(struct socket *so, u_long sndcc, u_long rcvcc) { if (sbreserve(&so->so_snd, sndcc) == 0) goto bad; if (sbreserve(&so->so_rcv, rcvcc) == 0) goto bad2; if (so->so_rcv.sb_lowat == 0) so->so_rcv.sb_lowat = 1; if (so->so_snd.sb_lowat == 0) so->so_snd.sb_lowat = MCLBYTES; if (so->so_snd.sb_lowat > so->so_snd.sb_hiwat) so->so_snd.sb_lowat = so->so_snd.sb_hiwat; return (0); bad2: sbrelease(&so->so_snd); bad: return (ENOBUFS); } /* * Allot mbufs to a sockbuf. * Attempt to scale mbmax so that mbcnt doesn't become limiting * if buffering efficiency is near the normal case. */ int sbreserve(struct sockbuf *sb, u_long cc) { if (cc == 0 || cc > sb_max) return (0); sb->sb_hiwat = cc; sb->sb_mbmax = min(cc * 2, sb_max + (sb_max / MCLBYTES) * MSIZE); if (sb->sb_lowat > sb->sb_hiwat) sb->sb_lowat = sb->sb_hiwat; return (1); } /* * If over 50% of mbuf clusters in use, do not accept any * greater than normal request. */ int sbcheckreserve(u_long cnt, u_long defcnt) { if (cnt > defcnt && mclpool.pr_nout> mclpool.pr_hardlimit / 2) return (ENOBUFS); return (0); } /* * Free mbufs held by a socket, and reserved mbuf space. */ void sbrelease(struct sockbuf *sb) { sbflush(sb); sb->sb_hiwat = sb->sb_mbmax = 0; } /* * Routines to add and remove * data from an mbuf queue. * * The routines sbappend() or sbappendrecord() are normally called to * append new mbufs to a socket buffer, after checking that adequate * space is available, comparing the function sbspace() with the amount * of data to be added. sbappendrecord() differs from sbappend() in * that data supplied is treated as the beginning of a new record. * To place a sender's address, optional access rights, and data in a * socket receive buffer, sbappendaddr() should be used. To place * access rights and data in a socket receive buffer, sbappendrights() * should be used. In either case, the new data begins a new record. * Note that unlike sbappend() and sbappendrecord(), these routines check * for the caller that there will be enough space to store the data. * Each fails if there is not enough space, or if it cannot find mbufs * to store additional information in. * * Reliable protocols may use the socket send buffer to hold data * awaiting acknowledgement. Data is normally copied from a socket * send buffer in a protocol with m_copy for output to a peer, * and then removing the data from the socket buffer with sbdrop() * or sbdroprecord() when the data is acknowledged by the peer. */ #ifdef SOCKBUF_DEBUG void sblastrecordchk(struct sockbuf *sb, const char *where) { struct mbuf *m = sb->sb_mb; while (m && m->m_nextpkt) m = m->m_nextpkt; if (m != sb->sb_lastrecord) { printf("sblastrecordchk: sb_mb %p sb_lastrecord %p last %p\n", sb->sb_mb, sb->sb_lastrecord, m); printf("packet chain:\n"); for (m = sb->sb_mb; m != NULL; m = m->m_nextpkt) printf("\t%p\n", m); panic("sblastrecordchk from %s", where); } } void sblastmbufchk(struct sockbuf *sb, const char *where) { struct mbuf *m = sb->sb_mb; struct mbuf *n; while (m && m->m_nextpkt) m = m->m_nextpkt; while (m && m->m_next) m = m->m_next; if (m != sb->sb_mbtail) { printf("sblastmbufchk: sb_mb %p sb_mbtail %p last %p\n", sb->sb_mb, sb->sb_mbtail, m); printf("packet tree:\n"); for (m = sb->sb_mb; m != NULL; m = m->m_nextpkt) { printf("\t"); for (n = m; n != NULL; n = n->m_next) printf("%p ", n); printf("\n"); } panic("sblastmbufchk from %s", where); } } #endif /* SOCKBUF_DEBUG */ #define SBLINKRECORD(sb, m0) \ do { \ if ((sb)->sb_lastrecord != NULL) \ (sb)->sb_lastrecord->m_nextpkt = (m0); \ else \ (sb)->sb_mb = (m0); \ (sb)->sb_lastrecord = (m0); \ } while (/*CONSTCOND*/0) /* * Append mbuf chain m to the last record in the * socket buffer sb. The additional space associated * the mbuf chain is recorded in sb. Empty mbufs are * discarded and mbufs are compacted where possible. */ void sbappend(struct sockbuf *sb, struct mbuf *m) { struct mbuf *n; if (m == NULL) return; SBLASTRECORDCHK(sb, "sbappend 1"); if ((n = sb->sb_lastrecord) != NULL) { /* * XXX Would like to simply use sb_mbtail here, but * XXX I need to verify that I won't miss an EOR that * XXX way. */ do { if (n->m_flags & M_EOR) { sbappendrecord(sb, m); /* XXXXXX!!!! */ return; } } while (n->m_next && (n = n->m_next)); } else { /* * If this is the first record in the socket buffer, it's * also the last record. */ sb->sb_lastrecord = m; } sbcompress(sb, m, n); SBLASTRECORDCHK(sb, "sbappend 2"); } /* * This version of sbappend() should only be used when the caller * absolutely knows that there will never be more than one record * in the socket buffer, that is, a stream protocol (such as TCP). */ void sbappendstream(struct sockbuf *sb, struct mbuf *m) { KDASSERT(m->m_nextpkt == NULL); KASSERT(sb->sb_mb == sb->sb_lastrecord); SBLASTMBUFCHK(sb, __func__); sbcompress(sb, m, sb->sb_mbtail); sb->sb_lastrecord = sb->sb_mb; SBLASTRECORDCHK(sb, __func__); } #ifdef SOCKBUF_DEBUG void sbcheck(struct sockbuf *sb) { struct mbuf *m; u_long len = 0, mbcnt = 0; for (m = sb->sb_mb; m; m = m->m_next) { len += m->m_len; mbcnt += MSIZE; if (m->m_flags & M_EXT) mbcnt += m->m_ext.ext_size; if (m->m_nextpkt) panic("sbcheck nextpkt"); } if (len != sb->sb_cc || mbcnt != sb->sb_mbcnt) { printf("cc %lu != %lu || mbcnt %lu != %lu\n", len, sb->sb_cc, mbcnt, sb->sb_mbcnt); panic("sbcheck"); } } #endif /* * As above, except the mbuf chain * begins a new record. */ void sbappendrecord(struct sockbuf *sb, struct mbuf *m0) { struct mbuf *m; if (m0 == NULL) return; /* * Put the first mbuf on the queue. * Note this permits zero length records. */ sballoc(sb, m0); SBLASTRECORDCHK(sb, "sbappendrecord 1"); SBLINKRECORD(sb, m0); m = m0->m_next; m0->m_next = NULL; if (m && (m0->m_flags & M_EOR)) { m0->m_flags &= ~M_EOR; m->m_flags |= M_EOR; } sbcompress(sb, m, m0); SBLASTRECORDCHK(sb, "sbappendrecord 2"); } /* * As above except that OOB data * is inserted at the beginning of the sockbuf, * but after any other OOB data. */ void sbinsertoob(struct sockbuf *sb, struct mbuf *m0) { struct mbuf *m, **mp; if (m0 == NULL) return; SBLASTRECORDCHK(sb, "sbinsertoob 1"); for (mp = &sb->sb_mb; (m = *mp) != NULL; mp = &((*mp)->m_nextpkt)) { again: switch (m->m_type) { case MT_OOBDATA: continue; /* WANT next train */ case MT_CONTROL: if ((m = m->m_next) != NULL) goto again; /* inspect THIS train further */ } break; } /* * Put the first mbuf on the queue. * Note this permits zero length records. */ sballoc(sb, m0); m0->m_nextpkt = *mp; if (*mp == NULL) { /* m0 is actually the new tail */ sb->sb_lastrecord = m0; } *mp = m0; m = m0->m_next; m0->m_next = NULL; if (m && (m0->m_flags & M_EOR)) { m0->m_flags &= ~M_EOR; m->m_flags |= M_EOR; } sbcompress(sb, m, m0); SBLASTRECORDCHK(sb, "sbinsertoob 2"); } /* * Append address and data, and optionally, control (ancillary) data * to the receive queue of a socket. If present, * m0 must include a packet header with total length. * Returns 0 if no space in sockbuf or insufficient mbufs. */ int sbappendaddr(struct sockbuf *sb, struct sockaddr *asa, struct mbuf *m0, struct mbuf *control) { struct mbuf *m, *n, *nlast; int space = asa->sa_len; if (m0 && (m0->m_flags & M_PKTHDR) == 0) panic("sbappendaddr"); if (m0) space += m0->m_pkthdr.len; for (n = control; n; n = n->m_next) { space += n->m_len; if (n->m_next == NULL) /* keep pointer to last control buf */ break; } if (space > sbspace(sb)) return (0); if (asa->sa_len > MLEN) return (0); MGET(m, M_DONTWAIT, MT_SONAME); if (m == NULL) return (0); m->m_len = asa->sa_len; bcopy(asa, mtod(m, caddr_t), asa->sa_len); if (n) n->m_next = m0; /* concatenate data to control */ else control = m0; m->m_next = control; SBLASTRECORDCHK(sb, "sbappendaddr 1"); for (n = m; n->m_next != NULL; n = n->m_next) sballoc(sb, n); sballoc(sb, n); nlast = n; SBLINKRECORD(sb, m); sb->sb_mbtail = nlast; SBLASTMBUFCHK(sb, "sbappendaddr"); SBLASTRECORDCHK(sb, "sbappendaddr 2"); return (1); } int sbappendcontrol(struct sockbuf *sb, struct mbuf *m0, struct mbuf *control) { struct mbuf *m, *mlast, *n; int space = 0; if (control == NULL) panic("sbappendcontrol"); for (m = control; ; m = m->m_next) { space += m->m_len; if (m->m_next == NULL) break; } n = m; /* save pointer to last control buffer */ for (m = m0; m; m = m->m_next) space += m->m_len; if (space > sbspace(sb)) return (0); n->m_next = m0; /* concatenate data to control */ SBLASTRECORDCHK(sb, "sbappendcontrol 1"); for (m = control; m->m_next != NULL; m = m->m_next) sballoc(sb, m); sballoc(sb, m); mlast = m; SBLINKRECORD(sb, control); sb->sb_mbtail = mlast; SBLASTMBUFCHK(sb, "sbappendcontrol"); SBLASTRECORDCHK(sb, "sbappendcontrol 2"); return (1); } /* * Compress mbuf chain m into the socket * buffer sb following mbuf n. If n * is null, the buffer is presumed empty. */ void sbcompress(struct sockbuf *sb, struct mbuf *m, struct mbuf *n) { int eor = 0; struct mbuf *o; while (m) { eor |= m->m_flags & M_EOR; if (m->m_len == 0 && (eor == 0 || (((o = m->m_next) || (o = n)) && o->m_type == m->m_type))) { if (sb->sb_lastrecord == m) sb->sb_lastrecord = m->m_next; m = m_free(m); continue; } if (n && (n->m_flags & M_EOR) == 0 && /* M_TRAILINGSPACE() checks buffer writeability */ m->m_len <= MCLBYTES / 4 && /* XXX Don't copy too much */ m->m_len <= M_TRAILINGSPACE(n) && n->m_type == m->m_type) { bcopy(mtod(m, caddr_t), mtod(n, caddr_t) + n->m_len, (unsigned)m->m_len); n->m_len += m->m_len; sb->sb_cc += m->m_len; if (m->m_type != MT_CONTROL && m->m_type != MT_SONAME) sb->sb_datacc += m->m_len; m = m_free(m); continue; } if (n) n->m_next = m; else sb->sb_mb = m; sb->sb_mbtail = m; sballoc(sb, m); n = m; m->m_flags &= ~M_EOR; m = m->m_next; n->m_next = NULL; } if (eor) { if (n) n->m_flags |= eor; else printf("semi-panic: sbcompress"); } SBLASTMBUFCHK(sb, __func__); } /* * Free all mbufs in a sockbuf. * Check that all resources are reclaimed. */ void sbflush(struct sockbuf *sb) { KASSERT((sb->sb_flags & SB_LOCK) == 0); while (sb->sb_mbcnt) sbdrop(sb, (int)sb->sb_cc); KASSERT(sb->sb_cc == 0); KASSERT(sb->sb_datacc == 0); KASSERT(sb->sb_mb == NULL); KASSERT(sb->sb_mbtail == NULL); KASSERT(sb->sb_lastrecord == NULL); } /* * Drop data from (the front of) a sockbuf. */ void sbdrop(struct sockbuf *sb, int len) { struct mbuf *m, *mn; struct mbuf *next; next = (m = sb->sb_mb) ? m->m_nextpkt : 0; while (len > 0) { if (m == NULL) { if (next == NULL) panic("sbdrop"); m = next; next = m->m_nextpkt; continue; } if (m->m_len > len) { m->m_len -= len; m->m_data += len; sb->sb_cc -= len; if (m->m_type != MT_CONTROL && m->m_type != MT_SONAME) sb->sb_datacc -= len; break; } len -= m->m_len; sbfree(sb, m); MFREE(m, mn); m = mn; } while (m && m->m_len == 0) { sbfree(sb, m); MFREE(m, mn); m = mn; } if (m) { sb->sb_mb = m; m->m_nextpkt = next; } else sb->sb_mb = next; /* * First part is an inline SB_EMPTY_FIXUP(). Second part * makes sure sb_lastrecord is up-to-date if we dropped * part of the last record. */ m = sb->sb_mb; if (m == NULL) { sb->sb_mbtail = NULL; sb->sb_lastrecord = NULL; } else if (m->m_nextpkt == NULL) sb->sb_lastrecord = m; } /* * Drop a record off the front of a sockbuf * and move the next record to the front. */ void sbdroprecord(struct sockbuf *sb) { struct mbuf *m, *mn; m = sb->sb_mb; if (m) { sb->sb_mb = m->m_nextpkt; do { sbfree(sb, m); MFREE(m, mn); } while ((m = mn) != NULL); } SB_EMPTY_FIXUP(sb); } /* * Create a "control" mbuf containing the specified data * with the specified type for presentation on a socket buffer. */ struct mbuf * sbcreatecontrol(caddr_t p, int size, int type, int level) { struct cmsghdr *cp; struct mbuf *m; if (CMSG_SPACE(size) > MCLBYTES) { printf("sbcreatecontrol: message too large %d\n", size); return NULL; } if ((m = m_get(M_DONTWAIT, MT_CONTROL)) == NULL) return ((struct mbuf *) NULL); if (CMSG_SPACE(size) > MLEN) { MCLGET(m, M_DONTWAIT); if ((m->m_flags & M_EXT) == 0) { m_free(m); return NULL; } } cp = mtod(m, struct cmsghdr *); bcopy(p, CMSG_DATA(cp), size); m->m_len = CMSG_SPACE(size); cp->cmsg_len = CMSG_LEN(size); cp->cmsg_level = level; cp->cmsg_type = type; return (m); }