Commit 10a13bb4 authored by Jonathan Lemon's avatar Jonathan Lemon Committed by Alexei Starovoitov
Browse files

libbpf: remove qidconf and better support external bpf programs. 



Use the recent change to XSKMAP bpf_map_lookup_elem() to test if
there is a xsk present in the map instead of duplicating the work
with qidconf.

Fix things so callers using XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD
bypass any internal bpf maps, so xsk_socket__{create|delete} works
properly.

Clean up error handling path.

Signed-off-by: default avatarJonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Tested-by: default avatarBjörn Töpel <bjorn.topel@intel.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 940e7be3

tools/lib/bpf/xsk.c

+28 −75
Original line number Diff line number Diff line
@@ -60,10 +60,8 @@ struct xsk_socket { 
	struct xsk_umem *umem;

	struct xsk_socket_config config;

	int fd;

	int xsks_map;

	int ifindex;

	int prog_fd;

	int qidconf_map_fd;

	int xsks_map_fd;

	__u32 queue_id;

	char ifname[IFNAMSIZ];
@@ -265,15 +263,11 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk) 
	/* This is the C-program:

	 * SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx)

	 * {

	 *     int *qidconf, index = ctx->rx_queue_index;

	 *     int index = ctx->rx_queue_index;

	 *

	 *     // A set entry here means that the correspnding queue_id

	 *     // has an active AF_XDP socket bound to it.

	 *     qidconf = bpf_map_lookup_elem(&qidconf_map, &index);

	 *     if (!qidconf)

	 *         return XDP_ABORTED;

	 *

	 *     if (*qidconf)

	 *     if (bpf_map_lookup_elem(&xsks_map, &index))

	 *         return bpf_redirect_map(&xsks_map, index, 0);

	 *

	 *     return XDP_PASS;
@@ -286,15 +280,10 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk) 
		BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_1, -4),

		BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),

		BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4),

		BPF_LD_MAP_FD(BPF_REG_1, xsk->qidconf_map_fd),

		BPF_LD_MAP_FD(BPF_REG_1, xsk->xsks_map_fd),

		BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),

		BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),

		BPF_MOV32_IMM(BPF_REG_0, 0),

		/* if r1 == 0 goto +8 */

		BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 8),

		BPF_MOV32_IMM(BPF_REG_0, 2),

		/* r1 = *(u32 *)(r1 + 0) */

		BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_1, 0),

		/* if r1 == 0 goto +5 */

		BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 5),

		/* r2 = *(u32 *)(r10 - 4) */
@@ -366,18 +355,11 @@ static int xsk_create_bpf_maps(struct xsk_socket *xsk) 
	if (max_queues < 0)

		return max_queues;



	fd = bpf_create_map_name(BPF_MAP_TYPE_ARRAY, "qidconf_map",

	fd = bpf_create_map_name(BPF_MAP_TYPE_XSKMAP, "xsks_map",

				 sizeof(int), sizeof(int), max_queues, 0);

	if (fd < 0)

		return fd;

	xsk->qidconf_map_fd = fd;



	fd = bpf_create_map_name(BPF_MAP_TYPE_XSKMAP, "xsks_map",

				 sizeof(int), sizeof(int), max_queues, 0);

	if (fd < 0) {

		close(xsk->qidconf_map_fd);

		return fd;

	}

	xsk->xsks_map_fd = fd;



	return 0;
@@ -385,10 +367,8 @@ static int xsk_create_bpf_maps(struct xsk_socket *xsk) 


static void xsk_delete_bpf_maps(struct xsk_socket *xsk)

{

	close(xsk->qidconf_map_fd);

	bpf_map_delete_elem(xsk->xsks_map_fd, &xsk->queue_id);

	close(xsk->xsks_map_fd);

	xsk->qidconf_map_fd = -1;

	xsk->xsks_map_fd = -1;

}



static int xsk_lookup_bpf_maps(struct xsk_socket *xsk)
@@ -417,10 +397,9 @@ static int xsk_lookup_bpf_maps(struct xsk_socket *xsk) 
	if (err)

		goto out_map_ids;



	for (i = 0; i < prog_info.nr_map_ids; i++) {

		if (xsk->qidconf_map_fd != -1 && xsk->xsks_map_fd != -1)

			break;

	xsk->xsks_map_fd = -1;



	for (i = 0; i < prog_info.nr_map_ids; i++) {

		fd = bpf_map_get_fd_by_id(map_ids[i]);

		if (fd < 0)

			continue;
@@ -431,11 +410,6 @@ static int xsk_lookup_bpf_maps(struct xsk_socket *xsk) 
			continue;

		}



		if (!strcmp(map_info.name, "qidconf_map")) {

			xsk->qidconf_map_fd = fd;

			continue;

		}



		if (!strcmp(map_info.name, "xsks_map")) {

			xsk->xsks_map_fd = fd;

			continue;
@@ -445,40 +419,18 @@ static int xsk_lookup_bpf_maps(struct xsk_socket *xsk) 
	}



	err = 0;

	if (xsk->qidconf_map_fd < 0 || xsk->xsks_map_fd < 0) {

	if (xsk->xsks_map_fd == -1)

		err = -ENOENT;

		xsk_delete_bpf_maps(xsk);

	}



out_map_ids:

	free(map_ids);

	return err;

}



static void xsk_clear_bpf_maps(struct xsk_socket *xsk)

{

	int qid = false;



	bpf_map_update_elem(xsk->qidconf_map_fd, &xsk->queue_id, &qid, 0);

	bpf_map_delete_elem(xsk->xsks_map_fd, &xsk->queue_id);

}



static int xsk_set_bpf_maps(struct xsk_socket *xsk)

{

	int qid = true, fd = xsk->fd, err;



	err = bpf_map_update_elem(xsk->qidconf_map_fd, &xsk->queue_id, &qid, 0);

	if (err)

		goto out;



	err = bpf_map_update_elem(xsk->xsks_map_fd, &xsk->queue_id, &fd, 0);

	if (err)

		goto out;



	return 0;

out:

	xsk_clear_bpf_maps(xsk);

	return err;

	return bpf_map_update_elem(xsk->xsks_map_fd, &xsk->queue_id,

				   &xsk->fd, 0);

}



static int xsk_setup_xdp_prog(struct xsk_socket *xsk)
@@ -497,28 +449,29 @@ static int xsk_setup_xdp_prog(struct xsk_socket *xsk) 
			return err;



		err = xsk_load_xdp_prog(xsk);

		if (err)

			goto out_maps;

		if (err) {

			xsk_delete_bpf_maps(xsk);

			return err;

		}

	} else {

		xsk->prog_fd = bpf_prog_get_fd_by_id(prog_id);

		err = xsk_lookup_bpf_maps(xsk);

		if (err)

			goto out_load;

		if (err) {

			close(xsk->prog_fd);

			return err;

		}

	}



	err = xsk_set_bpf_maps(xsk);

	if (err)

		goto out_load;



	return 0;



out_load:

	close(xsk->prog_fd);

out_maps:

	if (err) {

		xsk_delete_bpf_maps(xsk);

		close(xsk->prog_fd);

		return err;

	}



	return 0;

}



int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,

		       __u32 queue_id, struct xsk_umem *umem,

		       struct xsk_ring_cons *rx, struct xsk_ring_prod *tx,
@@ -643,9 +596,7 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, 
		goto out_mmap_tx;

	}



	xsk->qidconf_map_fd = -1;

	xsk->xsks_map_fd = -1;



	xsk->prog_fd = -1;

	if (!(xsk->config.libbpf_flags & XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD)) {

		err = xsk_setup_xdp_prog(xsk);

		if (err)
@@ -708,8 +659,10 @@ void xsk_socket__delete(struct xsk_socket *xsk) 
	if (!xsk)

		return;



	xsk_clear_bpf_maps(xsk);

	if (xsk->prog_fd != -1) {

		xsk_delete_bpf_maps(xsk);

		close(xsk->prog_fd);

	}



	optlen = sizeof(off);

	err = getsockopt(xsk->fd, SOL_XDP, XDP_MMAP_OFFSETS, &off, &optlen);

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