tools: ynl: generate code for ovs families

Add ovs_flow, ovs_vport and ovs_datapath to the families supported
in C. ovs-flow has some circular nesting which is fun to deal with,
but the necessary support has been added already in the previous
release cycle.

Add a sample that proves that dealing with fixed headers does
actually work correctly.

Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240202004926.447803-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/net/ynl/generated/Makefile

@@ -14,7 +14,7 @@ YNL_GEN_ARG_ethtool:=--user-header linux/ethtool_netlink.h \
 
 TOOL:=../ynl-gen-c.py
 
-GENS:=ethtool devlink dpll handshake fou mptcp_pm netdev nfsd
+GENS:=ethtool devlink dpll handshake fou mptcp_pm netdev nfsd ovs_datapath ovs_vport ovs_flow
 SRCS=$(patsubst %,%-user.c,${GENS})
 HDRS=$(patsubst %,%-user.h,${GENS})
 OBJS=$(patsubst %,%-user.o,${GENS})

tools/net/ynl/samples/.gitignore

@@ -1,4 +1,5 @@
 ethtool
 devlink
 netdev
+ovs
 page-pool

tools/net/ynl/samples/ovs.c

@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <string.h>
+
+#include <ynl.h>
+
+#include "ovs_datapath-user.h"
+
+int main(int argc, char **argv)
+{
+	struct ynl_sock *ys;
+	int err;
+
+	ys = ynl_sock_create(&ynl_ovs_datapath_family, NULL);
+	if (!ys)
+		return 1;
+
+	if (argc > 1) {
+		struct ovs_datapath_new_req *req;
+
+		req = ovs_datapath_new_req_alloc();
+		if (!req)
+			goto err_close;
+
+		ovs_datapath_new_req_set_upcall_pid(req, 1);
+		ovs_datapath_new_req_set_name(req, argv[1]);
+
+		err = ovs_datapath_new(ys, req);
+		ovs_datapath_new_req_free(req);
+		if (err)
+			goto err_close;
+	} else {
+		struct ovs_datapath_get_req_dump *req;
+		struct ovs_datapath_get_list *dps;
+
+		printf("Dump:\n");
+		req = ovs_datapath_get_req_dump_alloc();
+
+		dps = ovs_datapath_get_dump(ys, req);
+		ovs_datapath_get_req_dump_free(req);
+		if (!dps)
+			goto err_close;
+
+		ynl_dump_foreach(dps, dp) {
+			printf("  %s(%d): pid:%u cache:%u\n",
+			       dp->name, dp->_hdr.dp_ifindex,
+			       dp->upcall_pid, dp->masks_cache_size);
+		}
+		ovs_datapath_get_list_free(dps);
+	}
+
+	ynl_sock_destroy(ys);
+
+	return 0;
+
+err_close:
+	fprintf(stderr, "YNL (%d): %s\n", ys->err.code, ys->err.msg);
+	ynl_sock_destroy(ys);
+	return 2;
+}