From cbf07409d0c2afad7bb54be039490bffad8bc737 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Thu, 7 Nov 2019 18:47:36 +0100 Subject: [PATCH] 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: Magnus Karlsson Signed-off-by: Alexei Starovoitov Tested-by: William Tu Acked-by: Jonathan Lemon Link: https://lore.kernel.org/bpf/1573148860-30254-2-git-send-email-magnus.karlsson@intel.com --- 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"); + 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