20060303

1 files changed, 121 insertions, 0 deletions

diff --git a/os/ip/loopbackmedium.c b/os/ip/loopbackmedium.c
new file mode 100644
index 00000000..69d87449
--- /dev/null
+++ b/os/ip/loopbackmedium.c
@@ -0,0 +1,121 @@
+#include "u.h"
+#include "../port/lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "fns.h"
+#include "../port/error.h"
+
+#include "ip.h"
+
+enum
+{
+	Maxtu=	16*1024,
+};
+
+typedef struct LB LB;
+struct LB
+{
+	Proc	*readp;
+	Queue	*q;
+	Fs	*f;
+};
+
+static void loopbackread(void *a);
+
+static void
+loopbackbind(Ipifc *ifc, int, char**)
+{
+	LB *lb;
+
+	lb = smalloc(sizeof(*lb));
+	lb->f = ifc->conv->p->f;
+	/* TO DO: make queue size a function of kernel memory */
+	lb->q = qopen(128*1024, Qmsg, nil, nil);
+	ifc->arg = lb;
+	ifc->mbps = 1000;
+
+	kproc("loopbackread", loopbackread, ifc);
+
+}
+
+static void
+loopbackunbind(Ipifc *ifc)
+{
+	LB *lb = ifc->arg;
+
+	if(lb->readp)
+		postnote(lb->readp, 1, "unbind", 0);
+
+	/* wait for reader to die */
+	while(lb->readp != 0)
+		tsleep(&up->sleep, return0, 0, 300);
+
+	/* clean up */
+	qfree(lb->q);
+	free(lb);
+}
+
+static void
+loopbackbwrite(Ipifc *ifc, Block *bp, int, uchar*)
+{
+	LB *lb;
+
+	lb = ifc->arg;
+	if(qpass(lb->q, bp) < 0)
+		ifc->outerr++;
+	ifc->out++;
+}
+
+static void
+loopbackread(void *a)
+{
+	Ipifc *ifc;
+	Block *bp;
+	LB *lb;
+
+	ifc = a;
+	lb = ifc->arg;
+	lb->readp = up;	/* hide identity under a rock for unbind */
+	if(waserror()){
+		lb->readp = 0;
+		pexit("hangup", 1);
+	}
+	for(;;){
+		bp = qbread(lb->q, Maxtu);
+		if(bp == nil)
+			continue;
+		ifc->in++;
+		if(!canrlock(ifc)){
+			freeb(bp);
+			continue;
+		}
+		if(waserror()){
+			runlock(ifc);
+			nexterror();
+		}
+		if(ifc->lifc == nil)
+			freeb(bp);
+		else
+			ipiput4(lb->f, ifc, bp);
+		runlock(ifc);
+		poperror();
+	}
+}
+
+Medium loopbackmedium =
+{
+.hsize=		0,
+.mintu=		0,
+.maxtu=		Maxtu,
+.maclen=	0,
+.name=		"loopback",
+.bind=		loopbackbind,
+.unbind=	loopbackunbind,
+.bwrite=	loopbackbwrite,
+};
+
+void
+loopbackmediumlink(void)
+{
+	addipmedium(&loopbackmedium);
+}