lkml.org 
[lkml]   [2022]   [Jun]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH RFC bpf-next 12/52] libbpf: add ability to set the BTF/type ID on setting XDP prog
    Date
    Covered functions:
    * bpf_link_create() - via &bpf_link_create_ops;
    * bpf_link_update() - via &bpf_link_update_ops;
    * bpf_xdp_attach() - via &bpf_xdp_attach_ops;
    * bpf_set_link_xdp_fd_opts() - via &bpf_xdp_set_link_opts;

    bpf_link_update() got the ability to pass arbitrary link
    type-specific data to the kernel, not just the old and new FDs.
    No support for bpf_get_link_xdp_info()/&xdp_link_info as we store
    additional data such as flags and BTF ID in the kernel in BPF link
    mode only.

    Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
    ---
    tools/lib/bpf/bpf.c | 19 +++++++++++++++++++
    tools/lib/bpf/bpf.h | 16 +++++++++++++++-
    tools/lib/bpf/libbpf.h | 8 ++++++--
    tools/lib/bpf/netlink.c | 11 +++++++++++
    4 files changed, 51 insertions(+), 3 deletions(-)

    diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
    index 240186aac8e6..6036dc75cc7b 100644
    --- a/tools/lib/bpf/bpf.c
    +++ b/tools/lib/bpf/bpf.c
    @@ -805,6 +805,11 @@ int bpf_link_create(int prog_fd, int target_fd,
    if (!OPTS_ZEROED(opts, tracing))
    return libbpf_err(-EINVAL);
    break;
    + case BPF_XDP:
    + attr.link_create.xdp.btf_id = OPTS_GET(opts, xdp.btf_id, 0);
    + if (!OPTS_ZEROED(opts, xdp))
    + return libbpf_err(-EINVAL);
    + break;
    default:
    if (!OPTS_ZEROED(opts, flags))
    return libbpf_err(-EINVAL);
    @@ -872,6 +877,20 @@ int bpf_link_update(int link_fd, int new_prog_fd,
    attr.link_update.flags = OPTS_GET(opts, flags, 0);
    attr.link_update.old_prog_fd = OPTS_GET(opts, old_prog_fd, 0);

    + /* As the union in both @attr and @opts is unnamed, just use a pointer
    + * to any of its members to copy the whole rest of the union/opts
    + */
    + if (opts && opts->sz > offsetof(typeof(*opts), xdp)) {
    + __u32 attr_left, opts_left;
    +
    + attr_left = sizeof(attr.link_update) -
    + offsetof(typeof(attr.link_update), xdp);
    + opts_left = opts->sz - offsetof(typeof(*opts), xdp);
    +
    + memcpy(&attr.link_update.xdp, &opts->xdp,
    + min(attr_left, opts_left));
    + }
    +
    ret = sys_bpf(BPF_LINK_UPDATE, &attr, sizeof(attr));
    return libbpf_err_errno(ret);
    }
    diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
    index cabc03703e29..4e17995fdaff 100644
    --- a/tools/lib/bpf/bpf.h
    +++ b/tools/lib/bpf/bpf.h
    @@ -382,6 +382,10 @@ struct bpf_link_create_opts {
    struct {
    __u64 cookie;
    } tracing;
    + struct {
    + /* target metadata BTF + type ID */
    + __aligned_u64 btf_id;
    + } xdp;
    };
    size_t :0;
    };
    @@ -397,8 +401,18 @@ struct bpf_link_update_opts {
    size_t sz; /* size of this struct for forward/backward compatibility */
    __u32 flags; /* extra flags */
    __u32 old_prog_fd; /* expected old program FD */
    + /* must have the same layout as the same union from
    + * bpf_attr::link_update, uses direct memcpy() to there
    + */
    + union {
    + struct {
    + /* new target metadata BTF + type ID */
    + __aligned_u64 new_btf_id;
    + } xdp;
    + };
    + size_t :0;
    };
    -#define bpf_link_update_opts__last_field old_prog_fd
    +#define bpf_link_update_opts__last_field xdp.new_btf_id

    LIBBPF_API int bpf_link_update(int link_fd, int new_prog_fd,
    const struct bpf_link_update_opts *opts);
    diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
    index 4056e9038086..4f77128ba770 100644
    --- a/tools/lib/bpf/libbpf.h
    +++ b/tools/lib/bpf/libbpf.h
    @@ -1193,9 +1193,11 @@ struct xdp_link_info {
    struct bpf_xdp_set_link_opts {
    size_t sz;
    int old_fd;
    + __u32 :32;
    + __u64 btf_id;
    size_t :0;
    };
    -#define bpf_xdp_set_link_opts__last_field old_fd
    +#define bpf_xdp_set_link_opts__last_field btf_id

    LIBBPF_DEPRECATED_SINCE(0, 8, "use bpf_xdp_attach() instead")
    LIBBPF_API int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
    @@ -1211,9 +1213,11 @@ LIBBPF_API int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info,
    struct bpf_xdp_attach_opts {
    size_t sz;
    int old_prog_fd;
    + __u32 :32;
    + __u64 btf_id;
    size_t :0;
    };
    -#define bpf_xdp_attach_opts__last_field old_prog_fd
    +#define bpf_xdp_attach_opts__last_field btf_id

    struct bpf_xdp_query_opts {
    size_t sz;
    diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
    index 3a25178d0d12..104a809d5fb2 100644
    --- a/tools/lib/bpf/netlink.c
    +++ b/tools/lib/bpf/netlink.c
    @@ -235,6 +235,7 @@ struct __bpf_set_link_xdp_fd_opts {
    int fd;
    int old_fd;
    __u32 flags;
    + __u64 btf_id;
    };

    static int
    @@ -269,6 +270,12 @@ __bpf_set_link_xdp_fd_replace(const struct __bpf_set_link_xdp_fd_opts *opts)
    if (ret < 0)
    return ret;
    }
    + if (opts->btf_id) {
    + ret = nlattr_add(&req, IFLA_XDP_BTF_ID, &opts->btf_id,
    + sizeof(opts->btf_id));
    + if (ret < 0)
    + return ret;
    + }
    nlattr_end_nested(&req, nla);

    return libbpf_netlink_send_recv(&req, NULL, NULL, NULL);
    @@ -292,6 +299,8 @@ int bpf_xdp_attach(int ifindex, int prog_fd, __u32 flags, const struct bpf_xdp_a
    else
    sl_opts.old_fd = -1;

    + sl_opts.btf_id = OPTS_GET(opts, btf_id, 0);
    +
    err = __bpf_set_link_xdp_fd_replace(&sl_opts);
    return libbpf_err(err);
    }
    @@ -320,6 +329,8 @@ int bpf_set_link_xdp_fd_opts(int ifindex, int fd, __u32 flags,
    flags |= XDP_FLAGS_REPLACE;
    }

    + sl_opts.btf_id = OPTS_GET(opts, btf_id, 0);
    +
    ret = __bpf_set_link_xdp_fd_replace(&sl_opts);
    return libbpf_err(ret);
    }
    --
    2.36.1
    \
     
     \ /
      Last update: 2022-06-28 21:53    [W:4.073 / U:0.420 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site