Init

sys/os/uipc_socket2.c

@@ -0,0 +1,688 @@
+/*	@(#)uipc_socket2.c 1.1 94/10/31 SMI; from UCB 7.1 6/5/86	*/
+
+/*
+ * Copyright (c) 1982, 1986 Regents of the University of California.
+ * All rights reserved.  The Berkeley software License Agreement
+ * specifies the terms and conditions for redistribution.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/user.h>
+#include <sys/proc.h>
+#include <sys/file.h>
+#include <sys/buf.h>
+#include <sys/mbuf.h>
+#include <sys/protosw.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+
+int	nfs_wakeup_one_nfsd = 0;
+
+/*
+ * Primitive routines for operating on sockets and socket buffers
+ */
+
+/*
+ * 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.
+ */
+
+soisconnecting(so)
+	register struct socket *so;
+{
+
+	so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING);
+	so->so_state |= SS_ISCONNECTING;
+	if (so->so_wupalt)
+		(*so->so_wupalt->wup_func)(so, (caddr_t)&so->so_timeo,
+						so->so_wupalt->wup_arg);
+	else
+		wakeup((caddr_t)&so->so_timeo);
+}
+
+soisconnected(so)
+	register struct socket *so;
+{
+	register struct socket *head = so->so_head;
+
+	if (head) {
+		if (soqremque(so, 0) == 0)
+			panic("soisconnected");
+		soqinsque(head, so, 1);
+		sorwakeup(head);
+		if (head->so_wupalt)
+			(*head->so_wupalt->wup_func)(head,
+						(caddr_t)&head->so_timeo,
+						head->so_wupalt->wup_arg);
+		else
+			wakeup((caddr_t)&head->so_timeo);
+	}
+	so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING);
+	so->so_state |= SS_ISCONNECTED;
+	if (so->so_wupalt)
+		(*so->so_wupalt->wup_func)(so, (caddr_t)&so->so_timeo,
+						so->so_wupalt->wup_arg);
+	else
+		wakeup((caddr_t)&so->so_timeo);
+	sorwakeup(so);
+	sowwakeup(so);
+}
+
+soisdisconnecting(so)
+	register struct socket *so;
+{
+
+	so->so_state &= ~SS_ISCONNECTING;
+	so->so_state |= (SS_ISDISCONNECTING|SS_CANTRCVMORE|SS_CANTSENDMORE);
+	if (so->so_wupalt)
+		(*so->so_wupalt->wup_func)(so, (caddr_t)&so->so_timeo,
+						so->so_wupalt->wup_arg);
+	else
+		wakeup((caddr_t)&so->so_timeo);
+	sowwakeup(so);
+	sorwakeup(so);
+}
+
+soisdisconnected(so)
+	register struct socket *so;
+{
+
+	so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING);
+	so->so_state |= (SS_CANTRCVMORE|SS_CANTSENDMORE);
+	if (so->so_wupalt)
+		(*so->so_wupalt->wup_func)(so, (caddr_t)&so->so_timeo,
+						so->so_wupalt->wup_arg);
+	else
+		wakeup((caddr_t)&so->so_timeo);
+	sowwakeup(so);
+	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, propoerly linked into the
+ * data structure of the original socket, and return this.
+ */
+struct socket *
+sonewconn(head)
+	register struct socket *head;
+{
+	register struct socket *so;
+	register struct mbuf *m;
+
+	if (head->so_qlen + head->so_q0len > 3 * head->so_qlimit / 2)
+		goto bad;
+	m = m_getclr(M_DONTWAIT, MT_SOCKET);
+	if (m == NULL)
+		goto bad;
+	so = mtod(m, struct socket *);
+	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_pgrp = head->so_pgrp;
+	soqinsque(head, so, 0);
+	if ((*so->so_proto->pr_usrreq)(so, PRU_ATTACH,
+	    (struct mbuf *)0, (struct mbuf *)0, (struct mbuf *)0)) {
+		/*
+		 * The usrreq routine may already have called sofree,
+		 * which will have dequeued the socket.
+		 */
+		if (so->so_head)
+			(void) soqremque(so, 0);
+		(void) m_free(m);
+		goto bad;
+	}
+	return (so);
+bad:
+	return ((struct socket *)0);
+}
+
+soqinsque(head, so, q)
+	register struct socket *head, *so;
+	int q;
+{
+
+	so->so_head = head;
+	if (q == 0) {
+		head->so_q0len++;
+		so->so_q0 = head->so_q0;
+		head->so_q0 = so;
+	} else {
+		head->so_qlen++;
+		so->so_q = head->so_q;
+		head->so_q = so;
+	}
+}
+
+soqremque(so, q)
+	register struct socket *so;
+	int q;
+{
+	register struct socket *head, *prev, *next;
+
+	head = so->so_head;
+	/*
+	 * Better a panic than a bus error...
+	 */
+	if (head == NULL)
+		panic("soqremque");
+	prev = head;
+	for (;;) {
+		next = q ? prev->so_q : prev->so_q0;
+		if (next == so)
+			break;
+		if (next == head)
+			return (0);
+		prev = next;
+	}
+	if (q == 0) {
+		prev->so_q0 = next->so_q0;
+		head->so_q0len--;
+	} else {
+		prev->so_q = next->so_q;
+		head->so_qlen--;
+	}
+	next->so_q0 = next->so_q = 0;
+	next->so_head = 0;
+	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.
+ */
+
+socantsendmore(so)
+	struct socket *so;
+{
+
+	so->so_state |= SS_CANTSENDMORE;
+	sowwakeup(so);
+}
+
+socantrcvmore(so)
+	struct socket *so;
+{
+
+	so->so_state |= SS_CANTRCVMORE;
+	sorwakeup(so);
+	if (so->so_wupalt)
+		(*so->so_wupalt->wup_func)(so, (caddr_t)&so->so_timeo,
+						so->so_wupalt->wup_arg);
+}
+
+/*
+ * Socket select/wakeup routines.
+ */
+
+/*
+ * Queue a process for a select on a socket buffer.
+ */
+sbselqueue(sb)
+	struct sockbuf *sb;
+{
+	register struct proc *p;
+
+	if ((p = sb->sb_sel) && p->p_wchan == (caddr_t)&selwait)
+		sb->sb_flags |= SB_COLL;
+	else
+		sb->sb_sel = u.u_procp;
+}
+
+/*
+ * Wait for data to arrive at/drain from a socket buffer.
+ */
+sbwait(sb)
+	struct sockbuf *sb;
+{
+
+	sb->sb_flags |= SB_WAIT;
+	(void) sleep((caddr_t)&sb->sb_cc, PZERO+1);
+}
+
+/*
+ * Wakeup processes waiting on a socket buffer.
+ */
+sbwakeup(so, sb)
+	struct socket *so;
+	register struct sockbuf *sb;
+{
+
+	if (sb->sb_sel) {
+		selwakeup(sb->sb_sel, sb->sb_flags & SB_COLL);
+		sb->sb_sel = 0;
+		sb->sb_flags &= ~SB_COLL;
+	}
+	if (sb->sb_flags & SB_WAIT) {
+		sb->sb_flags &= ~SB_WAIT;
+		if (so->so_wupalt)
+			(*so->so_wupalt->wup_func)(so, (caddr_t)&sb->sb_cc,
+				so->so_wupalt->wup_arg);
+		else if (nfs_wakeup_one_nfsd == 1) {
+			/*
+			 * XXX:	wakeup_one should be redone to use
+			 *	so_wupalt->wup_func.  Actually, it should
+			 *	probably be obliterated altogether.
+			 */
+			wakeup_one((caddr_t)&sb->sb_cc);
+		} else
+			wakeup((caddr_t)&sb->sb_cc);
+	}
+}
+
+/*
+ * Wakeup socket readers and writers.
+ * Do asynchronous notification via SIGIO
+ * if the socket has the SS_ASYNC flag set.
+ */
+sowakeup(so, sb)
+	register struct socket *so;
+	struct sockbuf *sb;
+{
+	register struct proc *p;
+
+	sbwakeup(so, sb);
+	if (so->so_state & SS_ASYNC) {
+		if (so->so_pgrp < 0)
+			gsignal(-so->so_pgrp, SIGIO);
+		else if (so->so_pgrp > 0 && (p = pfind(so->so_pgrp)) != 0)
+			psignal(p, SIGIO);
+	}
+}
+
+/*
+ * 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 are maintained as a list of records.
+ * Each record is a list of mbufs chained together with the m_next
+ * field.  Records are chained together through the m_act fields of the
+ * records' first mbufs. The upper level routine soreceive() expects the
+ * following conventions to be observed when placing information in the
+ * receive buffer:
+ *
+ * 1. Each record consists of an address component, followed by a
+ *    rights component, followed by a data component.  Some of these
+ *    components may be missing, as described below.
+ * 2. If the protocol requires each message be preceded by the sender's
+ *    name, then mbufs containing that name must be present before any
+ *    associated data (mbuf's must be of type MT_SONAME).
+ * 3. 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 mbufs containing this data should
+ *    be present (mbuf's must be of type MT_RIGHTS).
+ *
+ * Note that the standard 4.3 version of soreceive can deal with no more
+ * than one (small) mbuf apiece of address and rights information.  The
+ * Sun version of soreceive can deal with arbitrary mbuf chains of both
+ * address and rights information.
+ *
+ * Before using a new socket structure it is first necessary to reserve
+ * buffer space to the socket, by calling sbreserve().  This commits
+ * some of the available buffer space in the system buffer pool for the
+ * socket.  The space should be released by calling sbrelease() when the
+ * socket is destroyed.
+ */
+
+soreserve(so, sndcc, rcvcc)
+	register struct socket *so;
+	int sndcc, rcvcc;
+{
+
+	if (sbreserve(&so->so_snd, sndcc) == 0)
+		goto bad;
+	if (sbreserve(&so->so_rcv, rcvcc) == 0)
+		goto bad2;
+	return (0);
+bad2:
+	sbrelease(&so->so_snd);
+bad:
+	return (ENOBUFS);
+}
+
+/*
+ * Allot mbufs to a sockbuf.
+ * Attempt to scale cc so that mbcnt doesn't become limiting
+ * if buffering efficiency is near the normal case.
+ */
+sbreserve(sb, cc)
+	struct sockbuf *sb;
+{
+
+	if ((unsigned) cc >
+	    (unsigned)SB_MAX * MCLBYTES / (2 * MSIZE + MCLBYTES))
+		return (0);
+	sb->sb_hiwat = cc;
+	sb->sb_mbmax = MIN(cc * 2, SB_MAX);
+	return (1);
+}
+
+/*
+ * Free mbufs held by a socket, and reserved mbuf space.
+ */
+sbrelease(sb)
+	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.
+ */
+
+/*
+ * 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.
+ */
+sbappend(sb, m)
+	struct sockbuf *sb;
+	struct mbuf *m;
+{
+	register struct mbuf *n;
+
+	if (m == 0)
+		return;
+	if (n = sb->sb_mb) {
+		while (n->m_act)
+			n = n->m_act;
+		while (n->m_next)
+			n = n->m_next;
+	}
+	sbcompress(sb, m, n);
+}
+
+/*
+ * As above, except the mbuf chain
+ * begins a new record.
+ */
+sbappendrecord(sb, m0)
+	register struct sockbuf *sb;
+	register struct mbuf *m0;
+{
+	register struct mbuf *m;
+
+	if (m0 == 0)
+		return;
+	if (m = sb->sb_mb)
+		while (m->m_act)
+			m = m->m_act;
+	/*
+	 * Put the first mbuf on the queue.
+	 * Note this permits zero length records.
+	 */
+	sballoc(sb, m0);
+	if (m)
+		m->m_act = m0;
+	else
+		sb->sb_mb = m0;
+	m = m0->m_next;
+	m0->m_next = 0;
+	sbcompress(sb, m, m0);
+}
+
+/*
+ * Append address and data, and optionally, rights
+ * to the receive queue of a socket.  Return 0 if
+ * no space in sockbuf or insufficient mbufs.
+ */
+sbappendaddr(sb, asa, m0, rights0)
+	register struct sockbuf *sb;
+	struct sockaddr *asa;
+	struct mbuf *rights0, *m0;
+{
+	register struct mbuf *m, *n;
+	int space = sizeof (*asa);
+
+	for (m = m0; m; m = m->m_next)
+		space += m->m_len;
+	if (rights0)
+		space += rights0->m_len;
+	if (space > sbspace(sb))
+		return (0);
+	MGET(m, M_DONTWAIT, MT_SONAME);
+	if (m == 0)
+		return (0);
+	*mtod(m, struct sockaddr *) = *asa;
+	m->m_len = sizeof (*asa);
+	if (rights0 && rights0->m_len) {
+		/* Attach rights following the address. */
+		m->m_next = m_copy(rights0, 0, rights0->m_len);
+		if (m->m_next == 0) {
+			m_freem(m);
+			return (0);
+		}
+		sballoc(sb, m->m_next);
+	}
+	/*
+	 * Attach address (and rights if present)
+	 * to the end of the socket's record chain
+	 * and get a pointer to the new chain end.
+	 */
+	sballoc(sb, m);
+	if (n = sb->sb_mb) {
+		while (n->m_act)
+			n = n->m_act;
+		n->m_act = m;
+	} else
+		sb->sb_mb = m;
+	if (m->m_next)
+		m = m->m_next;
+	/* Attach and compress data. */
+	if (m0)
+		sbcompress(sb, m0, m);
+	return (1);
+}
+
+sbappendrights(sb, m0, rights)
+	struct sockbuf *sb;
+	struct mbuf *rights, *m0;
+{
+	register struct mbuf *m, *n;
+	int space = 0;
+
+	if (rights == 0)
+		panic("sbappendrights");
+	for (m = m0; m; m = m->m_next)
+		space += m->m_len;
+	space += rights->m_len;
+	if (space > sbspace(sb))
+		return (0);
+	m = m_copy(rights, 0, rights->m_len);
+	if (m == 0)
+		return (0);
+	sballoc(sb, m);
+	if (n = sb->sb_mb) {
+		while (n->m_act)
+			n = n->m_act;
+		n->m_act = m;
+	} else
+		sb->sb_mb = m;
+	if (m0)
+		sbcompress(sb, m0, m);
+	return (1);
+}
+
+/*
+ * Compress mbuf chain m into the socket
+ * buffer sb following mbuf n.  If n
+ * is null, the buffer is presumed empty.
+ */
+sbcompress(sb, m, n)
+	register struct sockbuf *sb;
+	register struct mbuf *m, *n;
+{
+
+	while (m) {
+		if (m->m_len == 0) {
+			m = m_free(m);
+			continue;
+		}
+		/*
+		 * If neither the current not the next mbuf is a cluster
+		 * mbuf, the current mbuf has room, and the mbuf's types
+		 * match, copy the next in.
+		 */
+		if (n && n->m_off <= MMAXOFF && m->m_off <= MMAXOFF &&
+		    (n->m_off + n->m_len + m->m_len) <= MMAXOFF &&
+		    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;
+			m = m_free(m);
+			continue;
+		}
+		sballoc(sb, m);
+		if (n)
+			n->m_next = m;
+		else
+			sb->sb_mb = m;
+		n = m;
+		m = m->m_next;
+		n->m_next = 0;
+	}
+}
+
+/*
+ * Free all mbufs in a sockbuf.
+ * Check that all resources are reclaimed.
+ */
+sbflush(sb)
+	register struct sockbuf *sb;
+{
+
+	if (sb->sb_flags & SB_LOCK)
+		panic("sbflush");
+	while (sb->sb_mbcnt)
+		sbdrop(sb, (int)sb->sb_cc);
+	if (sb->sb_cc || sb->sb_mbcnt || sb->sb_mb)
+		panic("sbflush 2");
+}
+
+/*
+ * Drop data from (the front of) a sockbuf.
+ */
+sbdrop(sb, len)
+	register struct sockbuf *sb;
+	register int len;
+{
+	register struct mbuf *m, *mn;
+	struct mbuf *next;
+
+	next = (m = sb->sb_mb) ? m->m_act : 0;
+	while (len > 0) {
+		if (m == 0) {
+			if (next == 0)
+				panic("sbdrop");
+			m = next;
+			next = m->m_act;
+			continue;
+		}
+		if (m->m_len > len) {
+			m->m_len -= len;
+			m->m_off += len;
+			sb->sb_cc -= 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_act = next;
+	} else
+		sb->sb_mb = next;
+}
+
+/*
+ * Drop a record off the front of a sockbuf
+ * and move the next record to the front.
+ */
+sbdroprecord(sb)
+	register struct sockbuf *sb;
+{
+	register struct mbuf *m, *mn;
+
+	m = sb->sb_mb;
+	if (m) {
+		sb->sb_mb = m->m_act;
+		do {
+			sbfree(sb, m);
+			MFREE(m, mn);
+		} while (m = mn);
+	}
+}