Commit d60d81ac authored by Jakub Sitnicki's avatar Jakub Sitnicki Committed by Alexei Starovoitov
Browse files

libbpf: Add support for bpf_link-based netns attachment 



Add bpf_program__attach_nets(), which uses LINK_CREATE subcommand to create
an FD-based kernel bpf_link, for attach types tied to network namespace,
that is BPF_FLOW_DISSECTOR for the moment.

Signed-off-by: default avatarJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200531082846.2117903-7-jakub@cloudflare.com
parent 0c047ecb

tools/lib/bpf/libbpf.c

+18 −5
Original line number Diff line number Diff line
@@ -7896,8 +7896,9 @@ static struct bpf_link *attach_iter(const struct bpf_sec_def *sec, 
	return bpf_program__attach_iter(prog, NULL);

}



struct bpf_link *

bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd)

static struct bpf_link *

bpf_program__attach_fd(struct bpf_program *prog, int target_fd,

		       const char *target_name)

{

	enum bpf_attach_type attach_type;

	char errmsg[STRERR_BUFSIZE];
@@ -7917,12 +7918,12 @@ bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd) 
	link->detach = &bpf_link__detach_fd;



	attach_type = bpf_program__get_expected_attach_type(prog);

	link_fd = bpf_link_create(prog_fd, cgroup_fd, attach_type, NULL);

	link_fd = bpf_link_create(prog_fd, target_fd, attach_type, NULL);

	if (link_fd < 0) {

		link_fd = -errno;

		free(link);

		pr_warn("program '%s': failed to attach to cgroup: %s\n",

			bpf_program__title(prog, false),

		pr_warn("program '%s': failed to attach to %s: %s\n",

			bpf_program__title(prog, false), target_name,

			libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg)));

		return ERR_PTR(link_fd);

	}
@@ -7930,6 +7931,18 @@ bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd) 
	return link;

}



struct bpf_link *

bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd)

{

	return bpf_program__attach_fd(prog, cgroup_fd, "cgroup");

}



struct bpf_link *

bpf_program__attach_netns(struct bpf_program *prog, int netns_fd)

{

	return bpf_program__attach_fd(prog, netns_fd, "netns");

}



struct bpf_link *

bpf_program__attach_iter(struct bpf_program *prog,

			 const struct bpf_iter_attach_opts *opts)

tools/lib/bpf/libbpf.h

+2 −0
Original line number Diff line number Diff line
@@ -253,6 +253,8 @@ LIBBPF_API struct bpf_link * 
bpf_program__attach_lsm(struct bpf_program *prog);

LIBBPF_API struct bpf_link *

bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd);

LIBBPF_API struct bpf_link *

bpf_program__attach_netns(struct bpf_program *prog, int netns_fd);



struct bpf_map;

tools/lib/bpf/libbpf.map

+1 −0
Original line number Diff line number Diff line
@@ -262,6 +262,7 @@ LIBBPF_0.0.9 { 
		bpf_link_get_fd_by_id;

		bpf_link_get_next_id;

		bpf_program__attach_iter;

		bpf_program__attach_netns;

		perf_buffer__consume;

		ring_buffer__add;

		ring_buffer__consume;

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