Merge branch 'tools-ynl-user-space-c'

Jakub Kicinski says:

====================
tools: ynl: user space C

Use the code gen which is already in tree to generate a user space
library for a handful of simple families. I find YNL C quite useful
in some WIP projects, and I think others may find it useful, too.
I was hoping someone will pick this work up and finish it...
but it seems that Python YNL has largely stolen the thunder.
Python may not be great for selftest, tho, and actually this lib
is more fully-featured. The Python script was meant as a quick demo,
funny how those things go.

v2: https://lore.kernel.org/all/20230604175843.662084-1-kuba@kernel.org/
v1: https://lore.kernel.org/all/20230603052547.631384-1-kuba@kernel.org/
====================

Link: https://lore.kernel.org/r/20230605190108.809439-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 108 insertions, 0 deletions

diff --git a/tools/net/ynl/samples/netdev.c b/tools/net/ynl/samples/netdev.c
new file mode 100644
index 000000000000..d31268aa47c5
--- /dev/null
+++ b/tools/net/ynl/samples/netdev.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <string.h>
+
+#include <ynl.h>
+
+#include <net/if.h>
+
+#include "netdev-user.h"
+
+/* netdev genetlink family code sample
+ * This sample shows off basics of the netdev family but also notification
+ * handling, hence the somewhat odd UI. We subscribe to notifications first
+ * then wait for ifc selection, so the socket may already accumulate
+ * notifications as we wait. This allows us to test that YNL can handle
+ * requests and notifications getting interleaved.
+ */
+
+static void netdev_print_device(struct netdev_dev_get_rsp *d, unsigned int op)
+{
+	char ifname[IF_NAMESIZE];
+	const char *name;
+
+	if (!d->_present.ifindex)
+		return;
+
+	name = if_indextoname(d->ifindex, ifname);
+	if (name)
+		printf("%8s", name);
+	printf("[%d]\t", d->ifindex);
+
+	if (!d->_present.xdp_features)
+		return;
+
+	printf("%llx:", d->xdp_features);
+	for (int i = 0; d->xdp_features > 1U << i; i++) {
+		if (d->xdp_features & (1U << i))
+			printf(" %s", netdev_xdp_act_str(1 << i));
+	}
+
+	name = netdev_op_str(op);
+	if (name)
+		printf(" (ntf: %s)", name);
+	printf("\n");
+}
+
+int main(int argc, char **argv)
+{
+	struct netdev_dev_get_list *devs;
+	struct ynl_ntf_base_type *ntf;
+	struct ynl_error yerr;
+	struct ynl_sock *ys;
+	int ifindex = 0;
+
+	if (argc > 1)
+		ifindex = strtol(argv[1], NULL, 0);
+
+	ys = ynl_sock_create(&ynl_netdev_family, &yerr);
+	if (!ys) {
+		fprintf(stderr, "YNL: %s\n", yerr.msg);
+		return 1;
+	}
+
+	if (ynl_subscribe(ys, "mgmt"))
+		goto err_close;
+
+	printf("Select ifc ($ifindex; or 0 = dump; or -2 ntf check): ");
+	scanf("%d", &ifindex);
+
+	if (ifindex > 0) {
+		struct netdev_dev_get_req *req;
+		struct netdev_dev_get_rsp *d;
+
+		req = netdev_dev_get_req_alloc();
+		netdev_dev_get_req_set_ifindex(req, ifindex);
+
+		d = netdev_dev_get(ys, req);
+		netdev_dev_get_req_free(req);
+		if (!d)
+			goto err_close;
+
+		netdev_print_device(d, 0);
+		netdev_dev_get_rsp_free(d);
+	} else if (!ifindex) {
+		devs = netdev_dev_get_dump(ys);
+		if (!devs)
+			goto err_close;
+
+		ynl_dump_foreach(devs, d)
+			netdev_print_device(d, 0);
+		netdev_dev_get_list_free(devs);
+	} else if (ifindex == -2) {
+		ynl_ntf_check(ys);
+	}
+	while ((ntf = ynl_ntf_dequeue(ys))) {
+		netdev_print_device((struct netdev_dev_get_rsp *)&ntf->data,
+				    ntf->cmd);
+		ynl_ntf_free(ntf);
+	}
+
+	ynl_sock_destroy(ys);
+	return 0;
+
+err_close:
+	fprintf(stderr, "YNL: %s\n", ys->err.msg);
+	ynl_sock_destroy(ys);
+	return 2;
+}