Change semantics of socket close and detach. Add a new protocol switch

function, pru_close, to notify protocols that the file descriptor or
other consumer of a socket is closing the socket.  pru_abort is now a
notification of close also, and no longer detaches.  pru_detach is no
longer used to notify of close, and will be called during socket
tear-down by sofree() when all references to a socket evaporate after
an earlier call to abort or close the socket.  This means detach is now
an unconditional teardown of a socket, whereas previously sockets could
persist after detach of the protocol retained a reference.

This faciliates sharing mutexes between layers of the network stack as
the mutex is required during the checking and removal of references at
the head of sofree().  With this change, pru_detach can now assume that
the mutex will no longer be required by the socket layer after
completion, whereas before this was not necessarily true.

Reviewed by:	gnn

1 files changed, 14 insertions, 7 deletions

diff --git a/sys/netipx/ipx_usrreq.c b/sys/netipx/ipx_usrreq.c
index 489014a..84de629 100644
--- a/sys/netipx/ipx_usrreq.c
+++ b/sys/netipx/ipx_usrreq.c
@@ -88,6 +88,7 @@ static	int ipx_send(struct socket *so, int flags, struct mbuf *m,
 static	int ipx_shutdown(struct socket *so);
 static	int ripx_attach(struct socket *so, int proto, struct thread *td);
 static	int ipx_output(struct ipxpcb *ipxp, struct mbuf *m0);
+static	void ipx_usr_close(struct socket *so);
 
 struct	pr_usrreqs ipx_usrreqs = {
 	.pru_abort =		ipx_usr_abort,
@@ -101,6 +102,7 @@ struct	pr_usrreqs ipx_usrreqs = {
 	.pru_send =		ipx_send,
 	.pru_shutdown =		ipx_shutdown,
 	.pru_sockaddr =		ipx_sockaddr,
+	.pru_close =		ipx_usr_close,
 };
 
 struct	pr_usrreqs ripx_usrreqs = {
@@ -115,6 +117,7 @@ struct	pr_usrreqs ripx_usrreqs = {
 	.pru_send =		ipx_send,
 	.pru_shutdown =		ipx_shutdown,
 	.pru_sockaddr =		ipx_sockaddr,
+	.pru_close =		ipx_usr_close,
 };
 
 /*
@@ -432,14 +435,8 @@ static void
 ipx_usr_abort(so)
 	struct socket *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();
+	/* XXXRW: Possibly ipx_disconnect() here? */
 	soisdisconnected(so);
 }
 
@@ -482,6 +479,15 @@ ipx_bind(so, nam, td)
 	return (error);
 }
 
+static void
+ipx_usr_close(so)
+	struct socket *so;
+{
+
+	/* XXXRW: Possibly ipx_disconnect() here? */
+	soisdisconnected(so);
+}
+
 static int
 ipx_connect(so, nam, td)
 	struct socket *so;
@@ -513,6 +519,7 @@ ipx_detach(so)
 {
 	struct ipxpcb *ipxp = sotoipxpcb(so);
 
+	/* XXXRW: Should assert detached. */
 	KASSERT(ipxp != NULL, ("ipx_detach: ipxp == NULL"));
 	IPX_LIST_LOCK();
 	IPX_LOCK(ipxp);