tools/bpf: Add xdp set command for md btf

Introduce a new bpftool net subcommand and use it to report and set XDP
attributes:

$ /usr/local/sbin/bpftool net xdp help
Usage: /usr/local/sbin/bpftool net xdp { show | list | set | md_btf} [dev <devname>]
       /usr/local/sbin/bpftool xdp help

$ /usr/local/sbin/bpftool net xdp set dev mlx0 md_btf on

$ /usr/local/sbin/bpftool net xdp show
xdp:
mlx0(3) md_btf_id(1) md_btf_enabled(1)

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
Signed-off-by: Aravindhan Gunasekaran <aravindhan.gunasekaran@intel.com>

tools/bpf/bpftool/main.h

@@ -173,6 +173,7 @@ int do_btf(int argc, char **argv);
 
 /* non-bootstrap only commands */
 int do_prog(int argc, char **arg) __weak;
+int do_xdp(int argc, char **argv) __weak;
 int do_map(int argc, char **arg) __weak;
 int do_link(int argc, char **arg) __weak;
 int do_event_pipe(int argc, char **argv) __weak;
@@ -256,6 +257,7 @@ struct tcmsg;
 int do_xdp_dump(struct ifinfomsg *ifinfo, struct nlattr **tb);
 int do_filter_dump(struct tcmsg *ifinfo, struct nlattr **tb, const char *kind,
 		   const char *devname, int ifindex);
+int xdp_dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb);
 
 int print_all_levels(__maybe_unused enum libbpf_print_level level,
 		     const char *format, va_list args);

tools/bpf/bpftool/net.c

@@ -349,7 +349,7 @@ static int netlink_get_link(int sock, unsigned int nl_pid,
 			    dump_link_nlmsg, cookie);
 }
 
-static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb)
+int xdp_dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb)
 {
 	struct bpf_netdev_t *netinfo = cookie;
 	struct ifinfomsg *ifinfo = msg;
@@ -680,7 +680,7 @@ static int do_show(int argc, char **argv)
 		jsonw_start_array(json_wtr);
 	NET_START_OBJECT;
 	NET_START_ARRAY("xdp", "%s:\n");
-	ret = netlink_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array);
+	ret = netlink_get_link(sock, nl_pid, xdp_dump_link_nlmsg, &dev_array);
 	NET_END_ARRAY("\n");
 
 	if (!ret) {
@@ -722,7 +722,7 @@ static int do_help(int argc, char **argv)
 	}
 
 	fprintf(stderr,
-		"Usage: %1$s %2$s { show | list } [dev <devname>]\n"
+		"Usage: %1$s %2$s { show | list | xdp } [dev <devname>]\n"
 		"       %1$s %2$s attach ATTACH_TYPE PROG dev <devname> [ overwrite ]\n"
 		"       %1$s %2$s detach ATTACH_TYPE dev <devname>\n"
 		"       %1$s %2$s help\n"
@@ -747,6 +747,7 @@ static const struct cmd cmds[] = {
 	{ "list",	do_show },
 	{ "attach",	do_attach },
 	{ "detach",	do_detach },
+	{ "xdp",	do_xdp },
 	{ "help",	do_help },
 	{ 0 }
 };

tools/bpf/bpftool/xdp.c

@@ -0,0 +1,310 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+// Copyright (C) 2019 Mellanox.
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <time.h>
+#include <net/if.h>
+#include <linux/if.h>
+#include <linux/rtnetlink.h>
+#include <sys/socket.h>
+
+#include "bpf/nlattr.h"
+#include "main.h"
+#include "netlink_dumper.h"
+
+
+/* TODO: reuse  form net.c */
+#ifndef SOL_NETLINK
+#define SOL_NETLINK 270
+#endif
+
+static int netlink_open(__u32 *nl_pid)
+{
+	struct sockaddr_nl sa;
+	socklen_t addrlen;
+	int one = 1, ret;
+	int sock;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.nl_family = AF_NETLINK;
+
+	sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+	if (sock < 0)
+		return -errno;
+
+	if (setsockopt(sock, SOL_NETLINK, NETLINK_EXT_ACK,
+		       &one, sizeof(one)) < 0) {
+		p_err("Netlink error reporting not supported");
+	}
+
+	if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+		ret = -errno;
+		goto cleanup;
+	}
+
+	addrlen = sizeof(sa);
+	if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) {
+		ret = -errno;
+		goto cleanup;
+	}
+
+	if (addrlen != sizeof(sa)) {
+		ret = -LIBBPF_ERRNO__INTERNAL;
+		goto cleanup;
+	}
+
+	*nl_pid = sa.nl_pid;
+	return sock;
+
+cleanup:
+	close(sock);
+	return ret;
+}
+
+typedef int (*dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
+
+typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, dump_nlmsg_t, void *cookie);
+
+static int netlink_recv(int sock, __u32 nl_pid, __u32 seq,
+			__dump_nlmsg_t _fn, dump_nlmsg_t fn,
+			void *cookie)
+{
+	bool multipart = true;
+	struct nlmsgerr *err;
+	struct nlmsghdr *nh;
+	char buf[4096];
+	int len, ret;
+
+	while (multipart) {
+		multipart = false;
+		len = recv(sock, buf, sizeof(buf), 0);
+		if (len < 0) {
+			ret = -errno;
+			goto done;
+		}
+
+		if (len == 0)
+			break;
+
+		for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
+		     nh = NLMSG_NEXT(nh, len)) {
+			if (nh->nlmsg_pid != nl_pid) {
+				ret = -LIBBPF_ERRNO__WRNGPID;
+				goto done;
+			}
+			if (nh->nlmsg_seq != seq) {
+				ret = -LIBBPF_ERRNO__INVSEQ;
+				goto done;
+			}
+			if (nh->nlmsg_flags & NLM_F_MULTI)
+				multipart = true;
+			switch (nh->nlmsg_type) {
+			case NLMSG_ERROR:
+				err = (struct nlmsgerr *)NLMSG_DATA(nh);
+				if (!err->error)
+					continue;
+				ret = err->error;
+				libbpf_nla_dump_errormsg(nh);
+				goto done;
+			case NLMSG_DONE:
+				return 0;
+			default:
+				break;
+			}
+			if (_fn) {
+				ret = _fn(nh, fn, cookie);
+				if (ret)
+					return ret;
+			}
+		}
+	}
+	ret = 0;
+done:
+	return ret;
+}
+
+
+static int __dump_link_nlmsg(struct nlmsghdr *nlh,
+			     dump_nlmsg_t dump_link_nlmsg, void *cookie)
+{
+	struct nlattr *tb[IFLA_MAX + 1], *attr;
+	struct ifinfomsg *ifi = NLMSG_DATA(nlh);
+	int len;
+
+	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));
+	attr = (struct nlattr *) ((void *) ifi + NLMSG_ALIGN(sizeof(*ifi)));
+	if (libbpf_nla_parse(tb, IFLA_MAX, attr, len, NULL) != 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	return dump_link_nlmsg(cookie, ifi, tb);
+}
+
+static int netlink_get_link(int sock, unsigned int nl_pid,
+			    dump_nlmsg_t dump_link_nlmsg, void *cookie)
+{
+	struct {
+		struct nlmsghdr nlh;
+		struct ifinfomsg ifm;
+	} req = {
+		.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
+		.nlh.nlmsg_type = RTM_GETLINK,
+		.nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+		.ifm.ifi_family = AF_PACKET,
+	};
+	int seq = time(NULL);
+
+	req.nlh.nlmsg_seq = seq;
+	if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
+		return -errno;
+
+	return netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg,
+			    dump_link_nlmsg, cookie);
+}
+
+struct ip_devname_ifindex {
+	char	devname[64];
+	int	ifindex;
+};
+
+struct bpf_netdev_t {
+	struct ip_devname_ifindex *devices;
+	int	used_len;
+	int	array_len;
+	int	filter_idx;
+};
+
+static int do_show(int argc, char **argv)
+{
+	int sock, ret, filter_idx = -1;
+	struct bpf_netdev_t dev_array;
+	unsigned int nl_pid = 0;
+	char err_buf[256];
+
+	if (argc == 2) {
+		if (strcmp(argv[0], "dev") != 0)
+			usage();
+		filter_idx = if_nametoindex(argv[1]);
+		if (filter_idx == 0) {
+			fprintf(stderr, "invalid dev name %s\n", argv[1]);
+			return -1;
+		}
+	} else if (argc != 0) {
+		usage();
+	}
+
+	sock = netlink_open(&nl_pid);
+	if (sock < 0) {
+		fprintf(stderr, "failed to open netlink sock\n");
+		return -1;
+	}
+
+	dev_array.devices = NULL;
+	dev_array.used_len = 0;
+	dev_array.array_len = 0;
+	dev_array.filter_idx = filter_idx;
+
+	if (json_output)
+		jsonw_start_array(json_wtr);
+	NET_START_OBJECT;
+	NET_START_ARRAY("xdp", "%s:\n");
+	ret = netlink_get_link(sock, nl_pid, xdp_dump_link_nlmsg, &dev_array);
+	NET_END_ARRAY("\n");
+
+	NET_END_OBJECT;
+	if (json_output)
+		jsonw_end_array(json_wtr);
+
+	if (ret) {
+		if (json_output)
+			jsonw_null(json_wtr);
+		libbpf_strerror(ret, err_buf, sizeof(err_buf));
+		fprintf(stderr, "Error: %s\n", err_buf);
+	}
+	free(dev_array.devices);
+	close(sock);
+	return ret;
+}
+
+static int set_usage(void)
+{
+	fprintf(stderr,
+		"Usage: %s net xdp set dev <devname> {md_btf {on|off}}\n"
+		"       %s net xdp set help\n"
+		"       md_btf {on|off}: enable/disable meta data btf\n",
+		bin_name, bin_name);
+
+	return -1;
+}
+
+static int xdp_set_md_btf(int ifindex, char *arg)
+{
+	__u8 enable = (strcmp(arg, "on") == 0) ? 1 : 0;
+	int ret;
+
+	ret = bpf_set_link_xdp_md_btf(ifindex, enable);
+	if (ret)
+		fprintf(stderr, "Failed to setup xdp md, err=%d\n", ret);
+
+	return -ret;
+}
+
+static int do_set(int argc, char **argv)
+{
+	char *set_cmd, *set_arg;
+	int dev_idx = -1;
+
+	if (argc < 4)
+		return set_usage();
+
+	if (strcmp(argv[0], "dev") != 0)
+		return set_usage();
+
+	dev_idx = if_nametoindex(argv[1]);
+	if (dev_idx == 0) {
+		fprintf(stderr, "invalid dev name %s\n", argv[1]);
+		return -1;
+	}
+
+	set_cmd = argv[2];
+	set_arg = argv[3];
+
+	if (strcmp(set_cmd, "md_btf") != 0)
+		return set_usage();
+
+	if (strcmp(set_arg, "on") != 0 && strcmp(set_arg, "off") != 0)
+		return set_usage();
+
+	return xdp_set_md_btf(dev_idx, set_arg);
+}
+
+static int do_help(int argc, char **argv)
+{
+	if (json_output) {
+		jsonw_null(json_wtr);
+		return 0;
+	}
+
+	fprintf(stderr,
+		"Usage: %s %s xdp { show | list | set } [dev <devname>]\n"
+		"       %s %s help\n",
+		bin_name, argv[-2], bin_name, argv[-2]);
+
+	return 0;
+}
+
+static const struct cmd cmds[] = {
+	{ "show",        do_show },
+	{ "list",        do_show },
+	{ "set",         do_set  },
+	{ "help",        do_help },
+	{ 0 }
+};
+
+int do_xdp(int argc, char **argv)
+{
+	return cmd_select(cmds, argc, argv, do_help);
+}

tools/lib/bpf/libbpf.h

@@ -681,6 +681,7 @@ struct perf_buffer_opts {
 LIBBPF_API struct perf_buffer *
 perf_buffer__new(int map_fd, size_t page_cnt,
 		 const struct perf_buffer_opts *opts);
+LIBBPF_API int bpf_set_link_xdp_md_btf(int ifindex, __u8 enable);
 
 enum bpf_perf_event_ret {
 	LIBBPF_PERF_EVENT_DONE	= 0,

tools/lib/bpf/libbpf.map

@@ -135,6 +135,7 @@ LIBBPF_0.0.2 {
 		bpf_object__btf;
 		bpf_object__find_map_fd_by_name;
 		bpf_get_link_xdp_id;
+		bpf_set_link_xdp_md_btf;
 		btf__dedup;
 		btf__get_map_kv_tids;
 		btf__get_nr_types;