From 5750902a6e9bc6adb77da8257c0e34db2bfdebb2 Mon Sep 17 00:00:00 2001 From: Björn Töpel Date: Tue, 30 Apr 2019 14:45:36 +0200 Subject: libbpf: proper XSKMAP cleanup MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The bpf_map_update_elem() function, when used on an XSKMAP, will fail if not a valid AF_XDP socket is passed as value. Therefore, this is function cannot be used to clear the XSKMAP. Instead, the bpf_map_delete_elem() function should be used for that. This patch also simplifies the code by breaking up xsk_update_bpf_maps() into three smaller functions. Reported-by: William Tu Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Björn Töpel Tested-by: William Tu Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/xsk.c | 115 +++++++++++++++++++++++++++------------------------- 1 file changed, 60 insertions(+), 55 deletions(-) (limited to 'tools/lib/bpf') diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 78b4a4bd4a25..525f1cc163b5 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -387,21 +387,17 @@ static void xsk_delete_bpf_maps(struct xsk_socket *xsk) { close(xsk->qidconf_map_fd); close(xsk->xsks_map_fd); + xsk->qidconf_map_fd = -1; + xsk->xsks_map_fd = -1; } -static int xsk_update_bpf_maps(struct xsk_socket *xsk, int qidconf_value, - int xsks_value) +static int xsk_lookup_bpf_maps(struct xsk_socket *xsk) { - bool qidconf_map_updated = false, xsks_map_updated = false; + __u32 i, *map_ids, num_maps, prog_len = sizeof(struct bpf_prog_info); + __u32 map_len = sizeof(struct bpf_map_info); struct bpf_prog_info prog_info = {}; - __u32 prog_len = sizeof(prog_info); struct bpf_map_info map_info; - __u32 map_len = sizeof(map_info); - __u32 *map_ids; - int reset_value = 0; - __u32 num_maps; - unsigned int i; - int err; + int fd, err; err = bpf_obj_get_info_by_fd(xsk->prog_fd, &prog_info, &prog_len); if (err) @@ -422,66 +418,71 @@ static int xsk_update_bpf_maps(struct xsk_socket *xsk, int qidconf_value, goto out_map_ids; for (i = 0; i < prog_info.nr_map_ids; i++) { - int fd; + if (xsk->qidconf_map_fd != -1 && xsk->xsks_map_fd != -1) + break; fd = bpf_map_get_fd_by_id(map_ids[i]); - if (fd < 0) { - err = -errno; - goto out_maps; - } + if (fd < 0) + continue; err = bpf_obj_get_info_by_fd(fd, &map_info, &map_len); - if (err) - goto out_maps; + if (err) { + close(fd); + continue; + } if (!strcmp(map_info.name, "qidconf_map")) { - err = bpf_map_update_elem(fd, &xsk->queue_id, - &qidconf_value, 0); - if (err) - goto out_maps; - qidconf_map_updated = true; xsk->qidconf_map_fd = fd; - } else if (!strcmp(map_info.name, "xsks_map")) { - err = bpf_map_update_elem(fd, &xsk->queue_id, - &xsks_value, 0); - if (err) - goto out_maps; - xsks_map_updated = true; + continue; + } + + if (!strcmp(map_info.name, "xsks_map")) { xsk->xsks_map_fd = fd; + continue; } - if (qidconf_map_updated && xsks_map_updated) - break; + close(fd); } - if (!(qidconf_map_updated && xsks_map_updated)) { + err = 0; + if (xsk->qidconf_map_fd < 0 || xsk->xsks_map_fd < 0) { err = -ENOENT; - goto out_maps; + xsk_delete_bpf_maps(xsk); } - err = 0; - goto out_success; - -out_maps: - if (qidconf_map_updated) - (void)bpf_map_update_elem(xsk->qidconf_map_fd, &xsk->queue_id, - &reset_value, 0); - if (xsks_map_updated) - (void)bpf_map_update_elem(xsk->xsks_map_fd, &xsk->queue_id, - &reset_value, 0); -out_success: - if (qidconf_map_updated) - close(xsk->qidconf_map_fd); - if (xsks_map_updated) - close(xsk->xsks_map_fd); out_map_ids: free(map_ids); return err; } +static void xsk_clear_bpf_maps(struct xsk_socket *xsk) +{ + int qid = false; + + (void)bpf_map_update_elem(xsk->qidconf_map_fd, &xsk->queue_id, &qid, 0); + (void)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; +} + static int xsk_setup_xdp_prog(struct xsk_socket *xsk) { - bool prog_attached = false; __u32 prog_id = 0; int err; @@ -491,7 +492,6 @@ static int xsk_setup_xdp_prog(struct xsk_socket *xsk) return err; if (!prog_id) { - prog_attached = true; err = xsk_create_bpf_maps(xsk); if (err) return err; @@ -501,20 +501,21 @@ static int xsk_setup_xdp_prog(struct xsk_socket *xsk) goto out_maps; } else { xsk->prog_fd = bpf_prog_get_fd_by_id(prog_id); + err = xsk_lookup_bpf_maps(xsk); + if (err) + goto out_load; } - err = xsk_update_bpf_maps(xsk, true, xsk->fd); + err = xsk_set_bpf_maps(xsk); if (err) goto out_load; return 0; out_load: - if (prog_attached) - close(xsk->prog_fd); + close(xsk->prog_fd); out_maps: - if (prog_attached) - xsk_delete_bpf_maps(xsk); + xsk_delete_bpf_maps(xsk); return err; } @@ -642,6 +643,9 @@ 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; + if (!(xsk->config.libbpf_flags & XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD)) { err = xsk_setup_xdp_prog(xsk); if (err) @@ -706,7 +710,8 @@ void xsk_socket__delete(struct xsk_socket *xsk) if (!xsk) return; - (void)xsk_update_bpf_maps(xsk, 0, 0); + xsk_clear_bpf_maps(xsk); + xsk_delete_bpf_maps(xsk); optlen = sizeof(off); err = getsockopt(xsk->fd, SOL_XDP, XDP_MMAP_OFFSETS, &off, &optlen); -- cgit v1.2.3-59-g8ed1b