Hi Magnus,
Thanks for the patch.
On Thu, Nov 07, 2019 at 06:47:36PM +0100, Magnus Karlsson wrote:
> 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: Magnus Karlsson <magnus.karlsson@xxxxxxxxx>
> ---
> tools/lib/bpf/xsk.c | 27 +++++++++++++++++----------
> 1 file changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
> index 86c1b61..8ebd810 100644
> --- a/tools/lib/bpf/xsk.c
> +++ b/tools/lib/bpf/xsk.c
> @@ -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");
Why can't we use the existing default one in libbpf?
If users don't want to redistribute packet to different queue,
then they can still use the libbpf default one.
William
> + 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;
> - sxdp.sxdp_flags = xsk->config.bind_flags;
> + 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) {
> --
> 2.7.4
>
