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Commit 374fb54e authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

bpf: add own ctx rewriter on ifindex for clsact progs 



When fetching ifindex, we don't need to test dev for being NULL since
we're always guaranteed to have a valid dev for clsact programs. Thus,
avoid this test in fast path.

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f035a515

net/core/filter.c

+31 −6
Original line number Diff line number Diff line
@@ -2634,7 +2634,7 @@ void bpf_warn_invalid_xdp_action(u32 act) 
}

EXPORT_SYMBOL_GPL(bpf_warn_invalid_xdp_action);



static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg,

static u32 sk_filter_convert_ctx_access(enum bpf_access_type type, int dst_reg,

					int src_reg, int ctx_off,

					struct bpf_insn *insn_buf,

					struct bpf_prog *prog)
@@ -2785,6 +2785,31 @@ static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg, 
	return insn - insn_buf;

}



static u32 tc_cls_act_convert_ctx_access(enum bpf_access_type type, int dst_reg,

					 int src_reg, int ctx_off,

					 struct bpf_insn *insn_buf,

					 struct bpf_prog *prog)

{

	struct bpf_insn *insn = insn_buf;



	switch (ctx_off) {

	case offsetof(struct __sk_buff, ifindex):

		BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);



		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, dev),

				      dst_reg, src_reg,

				      offsetof(struct sk_buff, dev));

		*insn++ = BPF_LDX_MEM(BPF_W, dst_reg, dst_reg,

				      offsetof(struct net_device, ifindex));

		break;

	default:

		return sk_filter_convert_ctx_access(type, dst_reg, src_reg,

						    ctx_off, insn_buf, prog);

	}



	return insn - insn_buf;

}



static u32 xdp_convert_ctx_access(enum bpf_access_type type, int dst_reg,

				  int src_reg, int ctx_off,

				  struct bpf_insn *insn_buf,
@@ -2811,13 +2836,13 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, int dst_reg, 
static const struct bpf_verifier_ops sk_filter_ops = {

	.get_func_proto		= sk_filter_func_proto,

	.is_valid_access	= sk_filter_is_valid_access,

	.convert_ctx_access	= bpf_net_convert_ctx_access,

	.convert_ctx_access	= sk_filter_convert_ctx_access,

};



static const struct bpf_verifier_ops tc_cls_act_ops = {

	.get_func_proto		= tc_cls_act_func_proto,

	.is_valid_access	= tc_cls_act_is_valid_access,

	.convert_ctx_access	= bpf_net_convert_ctx_access,

	.convert_ctx_access	= tc_cls_act_convert_ctx_access,

};



static const struct bpf_verifier_ops xdp_ops = {