On Wed, Nov 4, 2020 at 10:07 PM Andrii Nakryiko
<andrii.nakryiko@xxxxxxxxx> wrote:
>
> On Wed, Nov 4, 2020 at 1:47 AM <mariusz.dudek@xxxxxxxxx> wrote:
> >
> > From: Mariusz Dudek <mariuszx.dudek@xxxxxxxxx>
> >
> > Add support for separation of eBPF program load and xsk socket
> > creation.
> >
> > This is needed for use-case when you want to privide as little
> > privileges as possible to the data plane application that will
> > handle xsk socket creation and incoming traffic.
> >
> > With this patch the data entity container can be run with only
> > CAP_NET_RAW capability to fulfill its purpose of creating xsk
> > socket and handling packages. In case your umem is larger or
> > equal process limit for MEMLOCK you need either increase the
> > limit or CAP_IPC_LOCK capability.
> >
> > To resolve privileges issue two APIs are introduced:
> >
> > - xsk_setup_xdp_prog - prepares bpf program if given and
> > loads it on a selected network interface or loads the built in
> > XDP program, if no XDP program is supplied. It can also return
> > xsks_map_fd which is needed by unprivileged process to update
> > xsks_map with AF_XDP socket "fd"
> >
> > - xsk_update_xskmap - inserts an AF_XDP socket into an xskmap
> > for a particular xsk_socket
> >
>
> Your commit message seems to be heavily shifted right...
>
Will be fixed
>
> > Signed-off-by: Mariusz Dudek <mariuszx.dudek@xxxxxxxxx>
> > ---
> > tools/lib/bpf/libbpf.map | 2 +
> > tools/lib/bpf/xsk.c | 157 ++++++++++++++++++++++++++++++++-------
> > tools/lib/bpf/xsk.h | 13 ++++
> > 3 files changed, 146 insertions(+), 26 deletions(-)
> >
>
> [...]
>
> > diff --git a/tools/lib/bpf/xsk.h b/tools/lib/bpf/xsk.h
> > index 1069c46364ff..c42b91935d3c 100644
> > --- a/tools/lib/bpf/xsk.h
> > +++ b/tools/lib/bpf/xsk.h
> > @@ -201,6 +201,19 @@ struct xsk_umem_config {
> > __u32 flags;
> > };
> >
> > +struct bpf_prog_cfg {
> > + struct bpf_insn *prog;
> > + const char *license;
> > + size_t insns_cnt;
> > + int xsks_map_fd;
> > +};
>
> This config will have problems with backward/forward compatibility.
> Please check how xxx_opts are done and use them for extensible options
> structs.
>
I will add struct size as first parameter and #define for __last_field
to be inline with xxx_opts
>
> > +
> > +LIBBPF_API int xsk_setup_xdp_prog(int ifindex,
> > + struct bpf_prog_cfg *cfg,
> > + int *xsks_map_fd);
> > +LIBBPF_API int xsk_update_xskmap(struct xsk_socket *xsk,
> > + int xsks_map_fd);
>
> this should be called xsk_socket__update_map? BTW, what's xskmap? Is
> that a special BPF map type?
>
I will change the API name as you suggested. XSKMAP is a special
BPF_MAP_TYPE_XSKMAP.
It defines how packets are being distributed from an XDP program to the XSKs.
> > +
> > /* Flags for the libbpf_flags field. */
> > #define XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD (1 << 0)
> >
> > --
> > 2.20.1
> >
