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authorMartin KaFai Lau <kafai@fb.com>2016-12-07 15:53:11 -0800
committerDavid S. Miller <davem@davemloft.net>2016-12-08 14:25:13 -0500
commit17bedab2723145d17b14084430743549e6943d03 (patch)
tree6a1517e36c1be543f591b5ff7fcd7e816dcc906a /kernel
parent8a03cf2cb7efe269913db079afb8c31f20bf0bef (diff)
downloadlinux-17bedab2723145d17b14084430743549e6943d03.tar.bz2
bpf: xdp: Allow head adjustment in XDP prog
This patch allows XDP prog to extend/remove the packet data at the head (like adding or removing header). It is done by adding a new XDP helper bpf_xdp_adjust_head(). It also renames bpf_helper_changes_skb_data() to bpf_helper_changes_pkt_data() to better reflect that XDP prog does not work on skb. This patch adds one "xdp_adjust_head" bit to bpf_prog for the XDP-capable driver to check if the XDP prog requires bpf_xdp_adjust_head() support. The driver can then decide to error out during XDP_SETUP_PROG. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/core.c2
-rw-r--r--kernel/bpf/syscall.c2
-rw-r--r--kernel/bpf/verifier.c2
3 files changed, 4 insertions, 2 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index bdcc9f4ba767..83e0d153b0b4 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1143,7 +1143,7 @@ struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
return prog;
}
-bool __weak bpf_helper_changes_skb_data(void *func)
+bool __weak bpf_helper_changes_pkt_data(void *func)
{
return false;
}
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 88f609f1c0c3..4819ec9d95f6 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -579,6 +579,8 @@ static void fixup_bpf_calls(struct bpf_prog *prog)
prog->dst_needed = 1;
if (insn->imm == BPF_FUNC_get_prandom_u32)
bpf_user_rnd_init_once();
+ if (insn->imm == BPF_FUNC_xdp_adjust_head)
+ prog->xdp_adjust_head = 1;
if (insn->imm == BPF_FUNC_tail_call) {
/* mark bpf_tail_call as different opcode
* to avoid conditional branch in
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 5b14f85f45c6..d28f9a3380a9 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1216,7 +1216,7 @@ static int check_call(struct bpf_verifier_env *env, int func_id)
return -EINVAL;
}
- changes_data = bpf_helper_changes_skb_data(fn->func);
+ changes_data = bpf_helper_changes_pkt_data(fn->func);
memset(&meta, 0, sizeof(meta));
meta.pkt_access = fn->pkt_access;