Rework IPX/SPX socket and pcb reference model:

- Introduce invariant that all IPX/SPX sockets will have valid so_pcb
  pointers to ipxpcb structures, and that for SPX, the control block
  pointer will always be valid.  Don't attempt to free the socket or
  pcb at various odd points, such as disconnect.

- Add a new ipxpcb flag, IPXP_DROPPED, which will be set in place of
  freeing PCB's so that this invariant can be maintained.  This flag
  is now checked instead of a NULL check in various socket protocol
  calls.

- Introduce many assertions that this invariant holds.

- Various pieces of code, such as the SPX timer code, no longer needs
  to jump through hoops in case it frees a PCB while running.

- Break out ipx_pcbfree() from ipx_pcbdetach().  Likewise
  spx_pcbdetach().

- Comment on some SMP-related limitations to the SPX code.

- Update copyrights.

MFC after:	1 month

1 files changed, 22 insertions, 11 deletions

diff --git a/sys/netipx/ipx_usrreq.c b/sys/netipx/ipx_usrreq.c
index 21e7612..7689d60 100644
--- a/sys/netipx/ipx_usrreq.c
+++ b/sys/netipx/ipx_usrreq.c
@@ -1,8 +1,9 @@
 /*-
- * Copyright (c) 2004-2005 Robert N. M. Watson
- * Copyright (c) 1995, Mike Mitchell
  * Copyright (c) 1984, 1985, 1986, 1987, 1993
- *	The Regents of the University of California.  All rights reserved.
+ *	The Regents of the University of California.
+ * Copyright (c) 1995, Mike Mitchell
+ * Copyright (c) 2004-2006 Robert N. M. Watson
+ * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -327,9 +328,8 @@ ipx_ctloutput(so, sopt)
 	struct ipx ioptval;
 	long seq;
 
+	KASSERT(ipxp != NULL, ("ipx_ctloutput: ipxp == NULL"));
 	error = 0;
-	if (ipxp == NULL)
-		return (EINVAL);
 
 	switch (sopt->sopt_dir) {
 	case SOPT_GET:
@@ -434,9 +434,11 @@ ipx_usr_abort(so)
 {
 	struct ipxpcb *ipxp = sotoipxpcb(so);
 
+	KASSERT(ipxp != NULL, ("ipx_usr_abort: ipxp == NULL"));
 	IPX_LIST_LOCK();
 	IPX_LOCK(ipxp);
 	ipx_pcbdetach(ipxp);
+	ipx_pcbfree(ipxp);
 	IPX_LIST_UNLOCK();
 	soisdisconnected(so);
 	ACCEPT_LOCK();
@@ -454,13 +456,13 @@ ipx_attach(so, proto, td)
 	struct ipxpcb *ipxp = sotoipxpcb(so);
 	int error;
 
-	if (ipxp != NULL)
-		return (EINVAL);
+	KASSERT(ipxp == NULL, ("ipx_attach: ipxp != NULL"));
+	error = soreserve(so, ipxsendspace, ipxrecvspace);
+	if (error != 0)
+		return (error);
 	IPX_LIST_LOCK();
 	error = ipx_pcballoc(so, &ipxpcb_list, td);
 	IPX_LIST_UNLOCK();
-	if (error == 0)
-		error = soreserve(so, ipxsendspace, ipxrecvspace);
 	return (error);
 }
 
@@ -473,6 +475,7 @@ ipx_bind(so, nam, td)
 	struct ipxpcb *ipxp = sotoipxpcb(so);
 	int error;
 
+	KASSERT(ipxp != NULL, ("ipx_bind: ipxp == NULL"));
 	IPX_LIST_LOCK();
 	IPX_LOCK(ipxp);
 	error = ipx_pcbbind(ipxp, nam, td);
@@ -490,6 +493,7 @@ ipx_connect(so, nam, td)
 	struct ipxpcb *ipxp = sotoipxpcb(so);
 	int error;
 
+	KASSERT(ipxp != NULL, ("ipx_connect: ipxp == NULL"));
 	IPX_LIST_LOCK();
 	IPX_LOCK(ipxp);
 	if (!ipx_nullhost(ipxp->ipxp_faddr)) {
@@ -511,11 +515,11 @@ ipx_detach(so)
 {
 	struct ipxpcb *ipxp = sotoipxpcb(so);
 
-	if (ipxp == NULL)
-		return (ENOTCONN);
+	KASSERT(ipxp != NULL, ("ipx_detach: ipxp == NULL"));
 	IPX_LIST_LOCK();
 	IPX_LOCK(ipxp);
 	ipx_pcbdetach(ipxp);
+	ipx_pcbfree(ipxp);
 	IPX_LIST_UNLOCK();
 	return (0);
 }
@@ -527,6 +531,7 @@ ipx_disconnect(so)
 	struct ipxpcb *ipxp = sotoipxpcb(so);
 	int error;
 
+	KASSERT(ipxp != NULL, ("ipx_disconnect: ipxp == NULL"));
 	IPX_LIST_LOCK();
 	IPX_LOCK(ipxp);
 	error = 0;
@@ -549,6 +554,7 @@ ipx_peeraddr(so, nam)
 {
 	struct ipxpcb *ipxp = sotoipxpcb(so);
 
+	KASSERT(ipxp != NULL, ("ipx_peeraddr: ipxp == NULL"));
 	ipx_setpeeraddr(ipxp, nam);
 	return (0);
 }
@@ -566,6 +572,7 @@ ipx_send(so, flags, m, nam, control, td)
 	struct ipxpcb *ipxp = sotoipxpcb(so);
 	struct ipx_addr laddr;
 
+	KASSERT(ipxp != NULL, ("ipxp_send: ipxp == NULL"));
 	/*
 	 * Attempt to only acquire the necessary locks: if the socket is
 	 * already connected, we don't need to hold the IPX list lock to be
@@ -619,6 +626,8 @@ static int
 ipx_shutdown(so)
 	struct socket *so;
 {
+
+	KASSERT(so->so_pcb != NULL, ("ipx_shutdown: so_pcb == NULL"));
 	socantsendmore(so);
 	return (0);
 }
@@ -630,6 +639,7 @@ ipx_sockaddr(so, nam)
 {
 	struct ipxpcb *ipxp = sotoipxpcb(so);
 
+	KASSERT(ipxp != NULL, ("ipx_sockaddr: ipxp == NULL"));
 	ipx_setsockaddr(ipxp, nam);
 	return (0);
 }
@@ -643,6 +653,7 @@ ripx_attach(so, proto, td)
 	int error = 0;
 	struct ipxpcb *ipxp = sotoipxpcb(so);
 
+	KASSERT(ipxp == NULL, ("ripx_attach: ipxp != NULL"));
 	if (td != NULL && (error = suser(td)) != 0)
 		return (error);
 	/*