X-Git-Url: https://git.subgeniuskitty.com/unix-history/.git/blobdiff_plain/388ca8bdac53637b23536f8f4129bf95680aed7e..5c723b90ceb41c125105d2a818e372ee31f2e522:/usr/src/sys/kern/uipc_socket2.c

diff --git a/usr/src/sys/kern/uipc_socket2.c b/usr/src/sys/kern/uipc_socket2.c
index 3a839988a4..5cffe304c4 100644
--- a/usr/src/sys/kern/uipc_socket2.c
+++ b/usr/src/sys/kern/uipc_socket2.c
@@ -1,19 +1,23 @@
-/*	uipc_socket2.c	4.5	81/11/21	*/
-
-#include "../h/param.h"
-#include "../h/systm.h"
-#include "../h/dir.h"
-#include "../h/user.h"
-#include "../h/proc.h"
-#include "../h/file.h"
-#include "../h/inode.h"
-#include "../h/buf.h"
-#include "../h/mbuf.h"
-#include "../h/protosw.h"
-#include "../h/socket.h"
-#include "../h/socketvar.h"
-#include "../net/inet.h"
-#include "../net/inet_systm.h"
+/*
+ * 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.
+ *
+ *	@(#)uipc_socket2.c	7.1 (Berkeley) %G%
+ */
+
+#include "param.h"
+#include "systm.h"
+#include "dir.h"
+#include "user.h"
+#include "proc.h"
+#include "file.h"
+#include "inode.h"
+#include "buf.h"
+#include "mbuf.h"
+#include "protosw.h"
+#include "socket.h"
+#include "socketvar.h"
 
 /*
  * Primitive routines for operating on sockets and socket buffers
@@ -21,10 +25,36 @@
 
 /*
  * Procedures to manipulate state flags of socket
- * and do appropriate wakeups.
+ * 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)
-	struct socket *so;
+	register struct socket *so;
 {
 
 	so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING);
@@ -33,25 +63,37 @@ soisconnecting(so)
 }
 
 soisconnected(so)
-	struct socket *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);
+		wakeup((caddr_t)&head->so_timeo);
+	}
 	so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING);
 	so->so_state |= SS_ISCONNECTED;
 	wakeup((caddr_t)&so->so_timeo);
+	sorwakeup(so);
+	sowwakeup(so);
 }
 
 soisdisconnecting(so)
-	struct socket *so;
+	register struct socket *so;
 {
 
-	so->so_state &= ~(SS_ISCONNECTED|SS_ISCONNECTING);
+	so->so_state &= ~SS_ISCONNECTING;
 	so->so_state |= (SS_ISDISCONNECTING|SS_CANTRCVMORE|SS_CANTSENDMORE);
 	wakeup((caddr_t)&so->so_timeo);
+	sowwakeup(so);
+	sorwakeup(so);
 }
 
 soisdisconnected(so)
-	struct socket *so;
+	register struct socket *so;
 {
 
 	so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING);
@@ -61,6 +103,100 @@ soisdisconnected(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)) {
+		(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;
+	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;
 {
@@ -78,25 +214,8 @@ socantrcvmore(so)
 }
 
 /*
- * Select a socket.
+ * Socket select/wakeup routines.
  */
-soselect(so, flag)
-	register struct socket *so;
-	int flag;
-{
-
-	if (flag & FREAD) {
-		if (soreadable(so))
-			return (1);
-		sbselqueue(&so->so_rcv);
-	}
-	if (flag & FWRITE) {
-		if (sowriteable(so))
-			return (1);
-		sbselqueue(&so->so_snd);
-	}
-	return (0);
-}
 
 /*
  * Queue a process for a select on a socket buffer.
@@ -127,7 +246,7 @@ sbwait(sb)
  * Wakeup processes waiting on a socket buffer.
  */
 sbwakeup(sb)
-	struct sockbuf *sb;
+	register struct sockbuf *sb;
 {
 
 	if (sb->sb_sel) {
@@ -141,17 +260,87 @@ sbwakeup(sb)
 	}
 }
 
+/*
+ * 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(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 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_act 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_RIGHTS).
+ * 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 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 (m_reserve(cc) == 0)
+	if ((unsigned) cc > (unsigned)SB_MAX * CLBYTES / (2 * MSIZE + CLBYTES))
 		return (0);
 	sb->sb_hiwat = cc;
-	sb->sb_mbmax = (cc*2)/MSIZE;
+	sb->sb_mbmax = MIN(cc * 2, SB_MAX);
 	return (1);
 }
 
@@ -163,35 +352,180 @@ sbrelease(sb)
 {
 
 	sbflush(sb);
-	m_release(sb->sb_hiwat);
 	sb->sb_hiwat = sb->sb_mbmax = 0;
 }
 
 /*
- * Routines to add (at the end) and remove (from the beginning)
- * data from a mbuf queue.
+ * 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 queue m to sockbuf sb.
+ * 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 **np, *n;
+	register struct mbuf *m, *n;
+	int space = sizeof (*asa);
 
-	np = &sb->sb_mb;
-	n = 0;
-	while (*np) {
-		n = *np;
-		np = &n->m_next;
+	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) {
+		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);
 	}
+	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;
+	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 (n && n->m_off <= MMAXOFF && m->m_off <= MMAXOFF &&
-		   (int)n->m_act == 0 && (int)m->m_act == 0 &&
-		   (n->m_off + n->m_len + m->m_off) <= MMAXOFF) {
-			bcopy(mtod(m, caddr_t), mtod(n, caddr_t),
+		    (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;
@@ -199,78 +533,89 @@ sbappend(sb, m)
 			continue;
 		}
 		sballoc(sb, m);
-		*np = m;
+		if (n)
+			n->m_next = m;
+		else
+			sb->sb_mb = m;
 		n = m;
-		np = &n->m_next;
 		m = m->m_next;
+		n->m_next = 0;
 	}
 }
 
-sbappendaddr(sb, asa, m0)
-	struct sockbuf *sb;
-	struct sockaddr *asa;
-	struct mbuf *m0;
-{
-	struct sockaddr *msa;
-	register struct mbuf *m;
-	register int len = sizeof (struct sockaddr);
-
-	for (m = m0; m; m = m->m_next)
-		len += m->m_len;
-	if (len > sbspace(sb))
-		return (0);
-	m = m_get(0);
-	if (m == 0)
-		return (0);
-	m->m_off = MMINOFF;
-	m->m_len = sizeof (struct sockaddr);
-	msa = mtod(m, struct sockaddr *);
-	*msa = *asa;
-	m->m_act = (struct mbuf *)1;
-	sbappend(sb, m);
-	m0->m_act = (struct mbuf *)1;
-	sbappend(sb, m0);
-	return (1);
-}
-
 /*
- * Free all mbufs on a sockbuf mbuf chain.
- * Check that resource allocations return to 0.
+ * Free all mbufs in a sockbuf.
+ * Check that all resources are reclaimed.
  */
 sbflush(sb)
-	struct sockbuf *sb;
+	register struct sockbuf *sb;
 {
 
 	if (sb->sb_flags & SB_LOCK)
 		panic("sbflush");
-	sbdrop(sb, sb->sb_cc);
+	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 chain.
+ * Drop data from (the front of) a sockbuf.
  */
 sbdrop(sb, len)
 	register struct sockbuf *sb;
 	register int len;
 {
-	register struct mbuf *m = sb->sb_mb, *mn;
+	register struct mbuf *m, *mn;
+	struct mbuf *next;
 
+	next = (m = sb->sb_mb) ? m->m_act : 0;
 	while (len > 0) {
-		if (m == 0)
-			panic("sbdrop");
-		if (m->m_len <= len) {
-			len -= m->m_len;
-			sbfree(sb, m);
-			MFREE(m, mn);
-			m = mn;
-		} else {
+		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);
 	}
-	sb->sb_mb = m;
 }