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authorMartin KaFai Lau <kafai@fb.com>2016-12-08 02:53:11 +0300
committerDavid S. Miller <davem@davemloft.net>2016-12-08 22:25:13 +0300
commit17bedab2723145d17b14084430743549e6943d03 (patch)
tree6a1517e36c1be543f591b5ff7fcd7e816dcc906a /net/core
parent8a03cf2cb7efe269913db079afb8c31f20bf0bef (diff)
downloadlinux-17bedab2723145d17b14084430743549e6943d03.tar.xz
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 'net/core')
-rw-r--r--net/core/filter.c28
1 files changed, 26 insertions, 2 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index b751202e12f8..b1461708a977 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2234,7 +2234,28 @@ static const struct bpf_func_proto bpf_skb_change_head_proto = {
.arg3_type = ARG_ANYTHING,
};
-bool bpf_helper_changes_skb_data(void *func)
+BPF_CALL_2(bpf_xdp_adjust_head, struct xdp_buff *, xdp, int, offset)
+{
+ void *data = xdp->data + offset;
+
+ if (unlikely(data < xdp->data_hard_start ||
+ data > xdp->data_end - ETH_HLEN))
+ return -EINVAL;
+
+ xdp->data = data;
+
+ return 0;
+}
+
+static const struct bpf_func_proto bpf_xdp_adjust_head_proto = {
+ .func = bpf_xdp_adjust_head,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+ .arg2_type = ARG_ANYTHING,
+};
+
+bool bpf_helper_changes_pkt_data(void *func)
{
if (func == bpf_skb_vlan_push ||
func == bpf_skb_vlan_pop ||
@@ -2244,7 +2265,8 @@ bool bpf_helper_changes_skb_data(void *func)
func == bpf_skb_change_tail ||
func == bpf_skb_pull_data ||
func == bpf_l3_csum_replace ||
- func == bpf_l4_csum_replace)
+ func == bpf_l4_csum_replace ||
+ func == bpf_xdp_adjust_head)
return true;
return false;
@@ -2670,6 +2692,8 @@ xdp_func_proto(enum bpf_func_id func_id)
return &bpf_xdp_event_output_proto;
case BPF_FUNC_get_smp_processor_id:
return &bpf_get_smp_processor_id_proto;
+ case BPF_FUNC_xdp_adjust_head:
+ return &bpf_xdp_adjust_head_proto;
default:
return sk_filter_func_proto(func_id);
}