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Commit 04949ccc authored by Daniel T. Lee's avatar Daniel T. Lee Committed by Alexei Starovoitov
Browse files

tools: bpftool: add net attach command to attach XDP on interface 



By this commit, using `bpftool net attach`, user can attach XDP prog on
interface. New type of enum 'net_attach_type' has been made, as stat ted at
cover-letter, the meaning of 'attach' is, prog will be attached on interface.

With 'overwrite' option at argument, attached XDP program could be replaced.
Added new helper 'net_parse_dev' to parse the network device at argument.

BPF prog will be attached through libbpf 'bpf_set_link_xdp_fd'.

Acked-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarDaniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent a9436dca

tools/bpf/bpftool/net.c

+129 −7
Original line number Diff line number Diff line
@@ -55,6 +55,35 @@ struct bpf_attach_info { 
	__u32 flow_dissector_id;

};



enum net_attach_type {

	NET_ATTACH_TYPE_XDP,

	NET_ATTACH_TYPE_XDP_GENERIC,

	NET_ATTACH_TYPE_XDP_DRIVER,

	NET_ATTACH_TYPE_XDP_OFFLOAD,

};



static const char * const attach_type_strings[] = {

	[NET_ATTACH_TYPE_XDP]		= "xdp",

	[NET_ATTACH_TYPE_XDP_GENERIC]	= "xdpgeneric",

	[NET_ATTACH_TYPE_XDP_DRIVER]	= "xdpdrv",

	[NET_ATTACH_TYPE_XDP_OFFLOAD]	= "xdpoffload",

};



const size_t net_attach_type_size = ARRAY_SIZE(attach_type_strings);



static enum net_attach_type parse_attach_type(const char *str)

{

	enum net_attach_type type;



	for (type = 0; type < net_attach_type_size; type++) {

		if (attach_type_strings[type] &&

		    is_prefix(str, attach_type_strings[type]))

			return type;

	}



	return net_attach_type_size;

}



static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb)

{

	struct bpf_netdev_t *netinfo = cookie;
@@ -223,6 +252,97 @@ static int query_flow_dissector(struct bpf_attach_info *attach_info) 
	return 0;

}



static int net_parse_dev(int *argc, char ***argv)

{

	int ifindex;



	if (is_prefix(**argv, "dev")) {

		NEXT_ARGP();



		ifindex = if_nametoindex(**argv);

		if (!ifindex)

			p_err("invalid devname %s", **argv);



		NEXT_ARGP();

	} else {

		p_err("expected 'dev', got: '%s'?", **argv);

		return -1;

	}



	return ifindex;

}



static int do_attach_detach_xdp(int progfd, enum net_attach_type attach_type,

				int ifindex, bool overwrite)

{

	__u32 flags = 0;



	if (!overwrite)

		flags = XDP_FLAGS_UPDATE_IF_NOEXIST;

	if (attach_type == NET_ATTACH_TYPE_XDP_GENERIC)

		flags |= XDP_FLAGS_SKB_MODE;

	if (attach_type == NET_ATTACH_TYPE_XDP_DRIVER)

		flags |= XDP_FLAGS_DRV_MODE;

	if (attach_type == NET_ATTACH_TYPE_XDP_OFFLOAD)

		flags |= XDP_FLAGS_HW_MODE;



	return bpf_set_link_xdp_fd(ifindex, progfd, flags);

}



static int do_attach(int argc, char **argv)

{

	enum net_attach_type attach_type;

	int progfd, ifindex, err = 0;

	bool overwrite = false;



	/* parse attach args */

	if (!REQ_ARGS(5))

		return -EINVAL;



	attach_type = parse_attach_type(*argv);

	if (attach_type == net_attach_type_size) {

		p_err("invalid net attach/detach type: %s", *argv);

		return -EINVAL;

	}

	NEXT_ARG();



	progfd = prog_parse_fd(&argc, &argv);

	if (progfd < 0)

		return -EINVAL;



	ifindex = net_parse_dev(&argc, &argv);

	if (ifindex < 1) {

		close(progfd);

		return -EINVAL;

	}



	if (argc) {

		if (is_prefix(*argv, "overwrite")) {

			overwrite = true;

		} else {

			p_err("expected 'overwrite', got: '%s'?", *argv);

			close(progfd);

			return -EINVAL;

		}

	}



	/* attach xdp prog */

	if (is_prefix("xdp", attach_type_strings[attach_type]))

		err = do_attach_detach_xdp(progfd, attach_type, ifindex,

					   overwrite);



	if (err < 0) {

		p_err("interface %s attach failed: %s",

		      attach_type_strings[attach_type], strerror(-err));

		return err;

	}



	if (json_output)

		jsonw_null(json_wtr);



	return 0;

}



static int do_show(int argc, char **argv)

{

	struct bpf_attach_info attach_info = {};
@@ -232,13 +352,9 @@ static int do_show(int argc, char **argv) 
	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]);

		filter_idx = net_parse_dev(&argc, &argv);

		if (filter_idx < 1)

			return -1;

		}

	} else if (argc != 0) {

		usage();

	}
@@ -305,13 +421,18 @@ static int do_help(int argc, char **argv) 


	fprintf(stderr,

		"Usage: %s %s { show | list } [dev <devname>]\n"

		"       %s %s attach ATTACH_TYPE PROG dev <devname> [ overwrite ]\n"

		"       %s %s help\n"

		"\n"

		"       " HELP_SPEC_PROGRAM "\n"

		"       ATTACH_TYPE := { xdp | xdpgeneric | xdpdrv | xdpoffload }\n"

		"\n"

		"Note: Only xdp and tc attachments are supported now.\n"

		"      For progs attached to cgroups, use \"bpftool cgroup\"\n"

		"      to dump program attachments. For program types\n"

		"      sk_{filter,skb,msg,reuseport} and lwt/seg6, please\n"

		"      consult iproute2.\n",

		bin_name, argv[-2], bin_name, argv[-2]);

		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2]);



	return 0;

}
@@ -319,6 +440,7 @@ static int do_help(int argc, char **argv) 
static const struct cmd cmds[] = {

	{ "show",	do_show },

	{ "list",	do_show },

	{ "attach",	do_attach },

	{ "help",	do_help },

	{ 0 }

};