ynl: samples: add tc filter example

Add a sample tool demonstrating how to add, dump, and delete a
flower filter with two VLAN push actions. The example can be
invoked as:

  # samples/tc-filter-add p2

    flower pref 1 proto: 0x8100
    flower:
      vlan_id: 100
      vlan_prio: 5
      num_of_vlans: 3
    action order: 1 vlan push id 200 protocol 0x8100 priority 0
    action order: 2 vlan push id 300 protocol 0x8100 priority 0

This verifies correct handling of tc action attributes for multiple
VLAN push actions. The tc action indexed arrays start from index 1,
and the index defines the action order. This behavior differs from
the YNL specification, which expects arrays to be zero-based. To
accommodate this, the example adds a dummy action at index 0, which
is ignored by the kernel.

Signed-off-by: Zahari Doychev <zahari.doychev@linux.com>
Link: https://patch.msgid.link/20251119203618.263780-2-zahari.doychev@linux.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/net/ynl/samples/.gitignore

@@ -7,3 +7,4 @@ rt-addr
 rt-link
 rt-route
 tc
+tc-filter-add

tools/net/ynl/samples/Makefile

@@ -19,6 +19,7 @@ include $(wildcard *.d)
 all: $(BINS)
 
 CFLAGS_page-pool=$(CFLAGS_netdev)
+CFLAGS_tc-filter-add:=$(CFLAGS_tc)
 
 $(BINS): ../lib/ynl.a ../generated/protos.a $(SRCS)
 	@echo -e '\tCC sample $@'

tools/net/ynl/samples/tc-filter-add.c

@@ -0,0 +1,335 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <arpa/inet.h>
+#include <linux/pkt_sched.h>
+#include <linux/tc_act/tc_vlan.h>
+#include <linux/tc_act/tc_gact.h>
+#include <linux/if_ether.h>
+#include <net/if.h>
+
+#include <ynl.h>
+
+#include "tc-user.h"
+
+#define TC_HANDLE (0xFFFF << 16)
+
+const char *vlan_act_name(struct tc_vlan *p)
+{
+	switch (p->v_action) {
+	case TCA_VLAN_ACT_POP:
+		return "pop";
+	case TCA_VLAN_ACT_PUSH:
+		return "push";
+	case TCA_VLAN_ACT_MODIFY:
+		return "modify";
+	default:
+		break;
+	}
+
+	return "not supported";
+}
+
+const char *gact_act_name(struct tc_gact *p)
+{
+	switch (p->action) {
+	case TC_ACT_SHOT:
+		return "drop";
+	case TC_ACT_OK:
+		return "ok";
+	case TC_ACT_PIPE:
+		return "pipe";
+	default:
+		break;
+	}
+
+	return "not supported";
+}
+
+static void print_vlan(struct tc_act_vlan_attrs *vlan)
+{
+	printf("%s ", vlan_act_name(vlan->parms));
+	if (vlan->_present.push_vlan_id)
+		printf("id %u ", vlan->push_vlan_id);
+	if (vlan->_present.push_vlan_protocol)
+		printf("protocol %#x ", ntohs(vlan->push_vlan_protocol));
+	if (vlan->_present.push_vlan_priority)
+		printf("priority %u ", vlan->push_vlan_priority);
+}
+
+static void print_gact(struct tc_act_gact_attrs *gact)
+{
+	struct tc_gact *p = gact->parms;
+
+	printf("%s ", gact_act_name(p));
+}
+
+static void flower_print(struct tc_flower_attrs *flower, const char *kind)
+{
+	struct tc_act_attrs *a;
+	unsigned int i;
+
+	printf("%s:\n", kind);
+
+	if (flower->_present.key_vlan_id)
+		printf("  vlan_id: %u\n", flower->key_vlan_id);
+	if (flower->_present.key_vlan_prio)
+		printf("  vlan_prio: %u\n", flower->key_vlan_prio);
+	if (flower->_present.key_num_of_vlans)
+		printf("  num_of_vlans: %u\n", flower->key_num_of_vlans);
+
+	for (i = 0; i < flower->_count.act; i++) {
+		a = &flower->act[i];
+		printf("action order: %i %s ", i + 1, a->kind);
+		if (a->options._present.vlan)
+			print_vlan(&a->options.vlan);
+		else if (a->options._present.gact)
+			print_gact(&a->options.gact);
+		printf("\n");
+	}
+	printf("\n");
+}
+
+static void tc_filter_print(struct tc_gettfilter_rsp *f)
+{
+	struct tc_options_msg *opt = &f->options;
+
+	if (opt->_present.flower)
+		flower_print(&opt->flower, f->kind);
+	else if (f->_len.kind)
+		printf("%s pref %u proto: %#x\n", f->kind,
+		       (f->_hdr.tcm_info >> 16),
+			ntohs(TC_H_MIN(f->_hdr.tcm_info)));
+}
+
+static int tc_filter_add(struct ynl_sock *ys, int ifi)
+{
+	struct tc_newtfilter_req *req;
+	struct tc_act_attrs *acts;
+	struct tc_vlan p = {
+		.action = TC_ACT_PIPE,
+		.v_action = TCA_VLAN_ACT_PUSH
+	};
+	__u16 flags = NLM_F_REQUEST | NLM_F_EXCL | NLM_F_CREATE;
+	int ret;
+
+	req = tc_newtfilter_req_alloc();
+	if (!req) {
+		fprintf(stderr, "tc_newtfilter_req_alloc failed\n");
+		return -1;
+	}
+	memset(req, 0, sizeof(*req));
+
+	acts = tc_act_attrs_alloc(3);
+	if (!acts) {
+		fprintf(stderr, "tc_act_attrs_alloc\n");
+		tc_newtfilter_req_free(req);
+		return -1;
+	}
+	memset(acts, 0, sizeof(*acts) * 3);
+
+	req->_hdr.tcm_ifindex = ifi;
+	req->_hdr.tcm_parent = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
+	req->_hdr.tcm_info = TC_H_MAKE(1 << 16, htons(ETH_P_8021Q));
+	req->chain = 0;
+
+	tc_newtfilter_req_set_nlflags(req, flags);
+	tc_newtfilter_req_set_kind(req, "flower");
+	tc_newtfilter_req_set_options_flower_key_vlan_id(req, 100);
+	tc_newtfilter_req_set_options_flower_key_vlan_prio(req, 5);
+	tc_newtfilter_req_set_options_flower_key_num_of_vlans(req, 3);
+
+	__tc_newtfilter_req_set_options_flower_act(req, acts, 3);
+
+	/* Skip action at index 0 because in TC, the action array
+	 * index starts at 1, with each index defining the action's
+	 * order. In contrast, in YNL indexed arrays start at index 0.
+	 */
+	tc_act_attrs_set_kind(&acts[1], "vlan");
+	tc_act_attrs_set_options_vlan_parms(&acts[1], &p, sizeof(p));
+	tc_act_attrs_set_options_vlan_push_vlan_id(&acts[1], 200);
+	tc_act_attrs_set_kind(&acts[2], "vlan");
+	tc_act_attrs_set_options_vlan_parms(&acts[2], &p, sizeof(p));
+	tc_act_attrs_set_options_vlan_push_vlan_id(&acts[2], 300);
+
+	tc_newtfilter_req_set_options_flower_flags(req, 0);
+	tc_newtfilter_req_set_options_flower_key_eth_type(req, htons(0x8100));
+
+	ret = tc_newtfilter(ys, req);
+	if (ret)
+		fprintf(stderr, "tc_newtfilter: %s\n", ys->err.msg);
+
+	tc_newtfilter_req_free(req);
+
+	return ret;
+}
+
+static int tc_filter_show(struct ynl_sock *ys, int ifi)
+{
+	struct tc_gettfilter_req_dump *req;
+	struct tc_gettfilter_list *rsp;
+
+	req = tc_gettfilter_req_dump_alloc();
+	if (!req) {
+		fprintf(stderr, "tc_gettfilter_req_dump_alloc failed\n");
+		return -1;
+	}
+	memset(req, 0, sizeof(*req));
+
+	req->_hdr.tcm_ifindex = ifi;
+	req->_hdr.tcm_parent = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
+	req->_present.chain = 1;
+	req->chain = 0;
+
+	rsp = tc_gettfilter_dump(ys, req);
+	tc_gettfilter_req_dump_free(req);
+	if (!rsp) {
+		fprintf(stderr, "YNL: %s\n", ys->err.msg);
+		return -1;
+	}
+
+	if (ynl_dump_empty(rsp))
+		fprintf(stderr, "Error: no filters reported\n");
+	else
+		ynl_dump_foreach(rsp, flt) tc_filter_print(flt);
+
+	tc_gettfilter_list_free(rsp);
+
+	return 0;
+}
+
+static int tc_filter_del(struct ynl_sock *ys, int ifi)
+{
+	struct tc_deltfilter_req *req;
+	__u16 flags = NLM_F_REQUEST;
+	int ret;
+
+	req = tc_deltfilter_req_alloc();
+	if (!req) {
+		fprintf(stderr, "tc_deltfilter_req_alloc failedq\n");
+		return -1;
+	}
+	memset(req, 0, sizeof(*req));
+
+	req->_hdr.tcm_ifindex = ifi;
+	req->_hdr.tcm_parent = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
+	req->_hdr.tcm_info = TC_H_MAKE(1 << 16, htons(ETH_P_8021Q));
+	tc_deltfilter_req_set_nlflags(req, flags);
+
+	ret = tc_deltfilter(ys, req);
+	if (ret)
+		fprintf(stderr, "tc_deltfilter failed: %s\n", ys->err.msg);
+
+	tc_deltfilter_req_free(req);
+
+	return ret;
+}
+
+static int tc_clsact_add(struct ynl_sock *ys, int ifi)
+{
+	struct tc_newqdisc_req *req;
+	__u16 flags = NLM_F_REQUEST | NLM_F_EXCL | NLM_F_CREATE;
+	int ret;
+
+	req = tc_newqdisc_req_alloc();
+	if (!req) {
+		fprintf(stderr, "tc_newqdisc_req_alloc failed\n");
+		return -1;
+	}
+	memset(req, 0, sizeof(*req));
+
+	req->_hdr.tcm_ifindex = ifi;
+	req->_hdr.tcm_parent = TC_H_CLSACT;
+	req->_hdr.tcm_handle = TC_HANDLE;
+	tc_newqdisc_req_set_nlflags(req, flags);
+	tc_newqdisc_req_set_kind(req, "clsact");
+
+	ret = tc_newqdisc(ys, req);
+	if (ret)
+		fprintf(stderr, "tc_newqdisc failed: %s\n", ys->err.msg);
+
+	tc_newqdisc_req_free(req);
+
+	return ret;
+}
+
+static int tc_clsact_del(struct ynl_sock *ys, int ifi)
+{
+	struct tc_delqdisc_req *req;
+	__u16 flags = NLM_F_REQUEST;
+	int ret;
+
+	req = tc_delqdisc_req_alloc();
+	if (!req) {
+		fprintf(stderr, "tc_delqdisc_req_alloc failed\n");
+		return -1;
+	}
+	memset(req, 0, sizeof(*req));
+
+	req->_hdr.tcm_ifindex = ifi;
+	req->_hdr.tcm_parent = TC_H_CLSACT;
+	req->_hdr.tcm_handle = TC_HANDLE;
+	tc_delqdisc_req_set_nlflags(req, flags);
+
+	ret = tc_delqdisc(ys, req);
+	if (ret)
+		fprintf(stderr, "tc_delqdisc failed: %s\n", ys->err.msg);
+
+	tc_delqdisc_req_free(req);
+
+	return ret;
+}
+
+static int tc_filter_config(struct ynl_sock *ys, int ifi)
+{
+	int ret = 0;
+
+	if (tc_filter_add(ys, ifi))
+		return -1;
+
+	ret = tc_filter_show(ys, ifi);
+
+	if (tc_filter_del(ys, ifi))
+		return -1;
+
+	return ret;
+}
+
+int main(int argc, char **argv)
+{
+	struct ynl_error yerr;
+	struct ynl_sock *ys;
+	int ifi, ret = 0;
+
+	if (argc < 2) {
+		fprintf(stderr, "Usage: %s <interface_name>\n", argv[0]);
+		return 1;
+	}
+	ifi = if_nametoindex(argv[1]);
+	if (!ifi) {
+		perror("if_nametoindex");
+		return 1;
+	}
+
+	ys = ynl_sock_create(&ynl_tc_family, &yerr);
+	if (!ys) {
+		fprintf(stderr, "YNL: %s\n", yerr.msg);
+		return 1;
+	}
+
+	if (tc_clsact_add(ys, ifi)) {
+		ret = 2;
+		goto err_destroy;
+	}
+
+	if (tc_filter_config(ys, ifi))
+		ret = 3;
+
+	if (tc_clsact_del(ys, ifi))
+		ret = 4;
+
+err_destroy:
+	ynl_sock_destroy(ys);
+	return ret;
+}