pipe: auto-create persistent VALE ports to support flexible naming

Author: giuseppelettieri

sys/dev/netmap/netmap_kern.h

@@ -872,6 +872,7 @@ struct netmap_vp_adapter {	/* VALE software port */
 	int bdg_port;
 	struct nm_bridge *na_bdg;
 	int retry;
+	int autodelete; /* remove the ifp on last reference */
 
 	/* Maximum Frame Size, used in bdg_mismatch_datapath() */
 	u_int mfs;
@@ -995,7 +996,10 @@ struct netmap_bwrap_adapter {
 	struct nm_bdg_polling_state *na_polling_state;
 };
 int netmap_bwrap_attach(const char *name, struct netmap_adapter *);
+int netmap_vi_create(struct nmreq *, int);
 
+#else /* !WITH_VALE */
+#define netmap_vi_create(nmr, a) (EOPNOTSUPP)
 #endif /* WITH_VALE */
 
 #ifdef WITH_PIPES

sys/dev/netmap/netmap_pipe.c

@@ -529,7 +529,7 @@ netmap_get_pipe_na(struct nmreq *nmr, struct netmap_adapter **na, int create)
 	struct ifnet *ifp = NULL;
 	u_int pipe_id;
 	int role = nmr->nr_flags & NR_REG_MASK;
-	int error;
+	int error, retries = 0;
 
 	ND("flags %x", nmr->nr_flags);
 
@@ -544,12 +544,28 @@ netmap_get_pipe_na(struct nmreq *nmr, struct netmap_adapter **na, int create)
 	memcpy(&pnmr.nr_name, nmr->nr_name, IFNAMSIZ);
 	/* pass to parent the requested number of pipes */
 	pnmr.nr_arg1 = nmr->nr_arg1;
-	error = netmap_get_na(&pnmr, &pna, &ifp, create);
-	if (error) {
-		ND("parent lookup failed: %d", error);
-		return error;
+	for (;;) {
+		int create_error;
+
+		error = netmap_get_na(&pnmr, &pna, &ifp, create);
+		if (!error)
+			break;
+		if (error != ENXIO || retries++) {
+			D("parent lookup failed: %d", error);
+			return error;
+		}
+		D("try to create a persistent vale port");
+		/* create a persistent vale port and try again */
+		NMG_UNLOCK();
+		create_error = netmap_vi_create(&pnmr, 1 /* autodelete */);
+		NMG_LOCK();
+		if (create_error) {
+			if (create_error != EOPNOTSUPP) {
+				D("failed to create a persistent vale port: %d", create_error);
+			}
+			return error;
+		}
 	}
-	ND("found parent: %s", na->name);
 
 	if (NETMAP_OWNED_BY_KERN(pna)) {
 		ND("parent busy");

sys/dev/netmap/netmap_vale.c

@@ -538,6 +538,13 @@ netmap_vp_dtor(struct netmap_adapter *na)
 	if (b) {
 		netmap_bdg_detach_common(b, vpna->bdg_port, -1);
 	}
+
+	if (vpna->autodelete && na->ifp != NULL) {
+		ND("releasing %s", na->ifp->if_xname);
+		NMG_UNLOCK();
+		nm_os_vi_detach(na->ifp);
+		NMG_LOCK();
+	}
 }
 
 /* remove a persistent VALE port from the system */
@@ -592,8 +599,8 @@ nm_update_info(struct nmreq *nmr, struct netmap_adapter *na)
  * Create a virtual interface registered to the system.
  * The interface will be attached to a bridge later.
  */
-static int
-nm_vi_create(struct nmreq *nmr)
+int
+netmap_vi_create(struct nmreq *nmr, int autodelete)
 {
 	struct ifnet *ifp;
 	struct netmap_vp_adapter *vpna;
@@ -628,7 +635,11 @@ nm_vi_create(struct nmreq *nmr)
 	}
 	/* persist-specific routines */
 	vpna->up.nm_bdg_ctl = netmap_vp_bdg_ctl;
-	netmap_adapter_get(&vpna->up);
+	if (!autodelete) {
+		netmap_adapter_get(&vpna->up);
+	} else {
+		vpna->autodelete = 1;
+	}
 	NM_ATTACH_NA(ifp, &vpna->up);
 	/* return the updated info */
 	error = nm_update_info(nmr, &vpna->up);
@@ -1160,7 +1171,7 @@ netmap_bdg_ctl(struct nmreq *nmr, struct netmap_bdg_ops *bdg_ops)
 
 	switch (cmd) {
 	case NETMAP_BDG_NEWIF:
-		error = nm_vi_create(nmr);
+		error = netmap_vi_create(nmr, 0 /* no autodelete */);
 		break;
 
 	case NETMAP_BDG_DELIF: