Commit cbf07409 authored by Magnus Karlsson's avatar Magnus Karlsson Committed by Alexei Starovoitov
Browse files

libbpf: Support XDP_SHARED_UMEM with external XDP program 



Add support in libbpf to create multiple sockets that share a single
umem. Note that an external XDP program need to be supplied that
routes the incoming traffic to the desired sockets. So you need to
supply the libbpf_flag XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD and load
your own XDP program.

Signed-off-by: default avatarMagnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Tested-by: default avatarWilliam Tu <u9012063@gmail.com>
Acked-by: default avatarJonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/bpf/1573148860-30254-2-git-send-email-magnus.karlsson@intel.com
parent 472aeb38

tools/lib/bpf/xsk.c

+17 −10
Original line number Diff line number Diff line
@@ -586,15 +586,21 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, 
	if (!umem || !xsk_ptr || !rx || !tx)

		return -EFAULT;



	if (umem->refcount) {

		pr_warn("Error: shared umems not supported by libbpf.\n");

		return -EBUSY;

	}



	xsk = calloc(1, sizeof(*xsk));

	if (!xsk)

		return -ENOMEM;



	err = xsk_set_xdp_socket_config(&xsk->config, usr_config);

	if (err)

		goto out_xsk_alloc;



	if (umem->refcount &&

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

		pr_warn("Error: shared umems not supported by libbpf supplied XDP program.\n");

		err = -EBUSY;

		goto out_xsk_alloc;

	}



	if (umem->refcount++ > 0) {

		xsk->fd = socket(AF_XDP, SOCK_RAW, 0);

		if (xsk->fd < 0) {
@@ -616,10 +622,6 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, 
	memcpy(xsk->ifname, ifname, IFNAMSIZ - 1);

	xsk->ifname[IFNAMSIZ - 1] = '\0';



	err = xsk_set_xdp_socket_config(&xsk->config, usr_config);

	if (err)

		goto out_socket;



	if (rx) {

		err = setsockopt(xsk->fd, SOL_XDP, XDP_RX_RING,

				 &xsk->config.rx_size,
@@ -687,7 +689,12 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, 
	sxdp.sxdp_family = PF_XDP;

	sxdp.sxdp_ifindex = xsk->ifindex;

	sxdp.sxdp_queue_id = xsk->queue_id;

	if (umem->refcount > 1) {

		sxdp.sxdp_flags = XDP_SHARED_UMEM;

		sxdp.sxdp_shared_umem_fd = umem->fd;

	} else {

		sxdp.sxdp_flags = xsk->config.bind_flags;

	}



	err = bind(xsk->fd, (struct sockaddr *)&sxdp, sizeof(sxdp));

	if (err) {