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author | Martin KaFai Lau <kafai@fb.com> | 2016-12-07 15:53:11 -0800 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2016-12-08 14:25:13 -0500 |
commit | 17bedab2723145d17b14084430743549e6943d03 (patch) | |
tree | 6a1517e36c1be543f591b5ff7fcd7e816dcc906a /net | |
parent | 8a03cf2cb7efe269913db079afb8c31f20bf0bef (diff) | |
download | linux-17bedab2723145d17b14084430743549e6943d03.tar.gz linux-17bedab2723145d17b14084430743549e6943d03.tar.bz2 linux-17bedab2723145d17b14084430743549e6943d03.zip |
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')
-rw-r--r-- | net/core/filter.c | 28 |
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); } |