From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: netdev@vger.kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, sdf@google.com,
posk@google.com, Willem de Bruijn <willemb@google.com>
Subject: [PATCH bpf-next 07/13] bpf: add bpf_skb_adjust_room mode BPF_ADJ_ROOM_MAC
Date: Wed, 20 Mar 2019 10:49:38 -0400 [thread overview]
Message-ID: <20190320144944.147862-8-willemdebruijn.kernel@gmail.com> (raw)
In-Reply-To: <20190320144944.147862-1-willemdebruijn.kernel@gmail.com>
From: Willem de Bruijn <willemb@google.com>
bpf_skb_adjust_room net allows inserting room in an skb.
Existing mode BPF_ADJ_ROOM_NET inserts room after the network header
by pulling the skb, moving the network header forward and zeroing the
new space.
Add new mode BPF_ADJUST_ROOM_MAC that inserts room after the mac
header. This allows inserting tunnel headers in front of the network
header without having to recreate the network header in the original
space, avoiding two copies.
Signed-off-by: Willem de Bruijn <willemb@google.com>
---
include/uapi/linux/bpf.h | 6 +++++-
net/core/filter.c | 38 ++++++++++++++++++++------------------
2 files changed, 25 insertions(+), 19 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 929c8e537a14a..4f5c918e6fcf4 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1478,7 +1478,10 @@ union bpf_attr {
* Grow or shrink the room for data in the packet associated to
* *skb* by *len_diff*, and according to the selected *mode*.
*
- * There is a single supported mode at this time:
+ * There are two supported modes at this time:
+ *
+ * * **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
+ * (room space is added or removed below the layer 2 header).
*
* * **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
* (room space is added or removed below the layer 3 header).
@@ -2593,6 +2596,7 @@ enum bpf_func_id {
/* Mode for BPF_FUNC_skb_adjust_room helper. */
enum bpf_adj_room_mode {
BPF_ADJ_ROOM_NET,
+ BPF_ADJ_ROOM_MAC,
};
/* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
diff --git a/net/core/filter.c b/net/core/filter.c
index 8e15fb919b574..1a0cf578b4502 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2963,9 +2963,8 @@ static u32 bpf_skb_net_base_len(const struct sk_buff *skb)
}
}
-static int bpf_skb_net_grow(struct sk_buff *skb, u32 len_diff)
+static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff)
{
- u32 off = skb_mac_header_len(skb) + bpf_skb_net_base_len(skb);
int ret;
if (skb_is_gso(skb) && !skb_is_gso_tcp(skb))
@@ -2992,9 +2991,8 @@ static int bpf_skb_net_grow(struct sk_buff *skb, u32 len_diff)
return 0;
}
-static int bpf_skb_net_shrink(struct sk_buff *skb, u32 len_diff)
+static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff)
{
- u32 off = skb_mac_header_len(skb) + bpf_skb_net_base_len(skb);
int ret;
if (skb_is_gso(skb) && !skb_is_gso_tcp(skb))
@@ -3027,7 +3025,8 @@ static u32 __bpf_skb_max_len(const struct sk_buff *skb)
SKB_MAX_ALLOC;
}
-static int bpf_skb_adjust_net(struct sk_buff *skb, s32 len_diff)
+BPF_CALL_4(bpf_skb_adjust_room, struct sk_buff *, skb, s32, len_diff,
+ u32, mode, u64, flags)
{
bool trans_same = skb->transport_header == skb->network_header;
u32 len_cur, len_diff_abs = abs(len_diff);
@@ -3035,14 +3034,28 @@ static int bpf_skb_adjust_net(struct sk_buff *skb, s32 len_diff)
u32 len_max = __bpf_skb_max_len(skb);
__be16 proto = skb->protocol;
bool shrink = len_diff < 0;
+ u32 off;
int ret;
+ if (unlikely(flags))
+ return -EINVAL;
if (unlikely(len_diff_abs > 0xfffU))
return -EFAULT;
if (unlikely(proto != htons(ETH_P_IP) &&
proto != htons(ETH_P_IPV6)))
return -ENOTSUPP;
+ off = skb_mac_header_len(skb);
+ switch (mode) {
+ case BPF_ADJ_ROOM_NET:
+ off += bpf_skb_net_base_len(skb);
+ break;
+ case BPF_ADJ_ROOM_MAC:
+ break;
+ default:
+ return -ENOTSUPP;
+ }
+
len_cur = skb->len - skb_network_offset(skb);
if (skb_transport_header_was_set(skb) && !trans_same)
len_cur = skb_network_header_len(skb);
@@ -3052,24 +3065,13 @@ static int bpf_skb_adjust_net(struct sk_buff *skb, s32 len_diff)
!skb_is_gso(skb))))
return -ENOTSUPP;
- ret = shrink ? bpf_skb_net_shrink(skb, len_diff_abs) :
- bpf_skb_net_grow(skb, len_diff_abs);
+ ret = shrink ? bpf_skb_net_shrink(skb, off, len_diff_abs) :
+ bpf_skb_net_grow(skb, off, len_diff_abs);
bpf_compute_data_pointers(skb);
return ret;
}
-BPF_CALL_4(bpf_skb_adjust_room, struct sk_buff *, skb, s32, len_diff,
- u32, mode, u64, flags)
-{
- if (unlikely(flags))
- return -EINVAL;
- if (likely(mode == BPF_ADJ_ROOM_NET))
- return bpf_skb_adjust_net(skb, len_diff);
-
- return -ENOTSUPP;
-}
-
static const struct bpf_func_proto bpf_skb_adjust_room_proto = {
.func = bpf_skb_adjust_room,
.gpl_only = false,
--
2.21.0.225.g810b269d1ac-goog
next prev parent reply other threads:[~2019-03-20 14:50 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-20 14:49 [PATCH bpf-next 00/13] bpf tc tunneling Willem de Bruijn
2019-03-20 14:49 ` [PATCH bpf-next 01/13] bpf: in bpf_skb_adjust_room avoid copy in tx fast path Willem de Bruijn
2019-03-20 14:49 ` [PATCH bpf-next 02/13] selftests/bpf: bpf tunnel encap test Willem de Bruijn
2019-03-20 14:49 ` [PATCH bpf-next 03/13] selftests/bpf: expand bpf tunnel test with decap Willem de Bruijn
2019-03-20 14:49 ` [PATCH bpf-next 04/13] selftests/bpf: expand bpf tunnel test to ipv6 Willem de Bruijn
2019-03-20 14:49 ` [PATCH bpf-next 05/13] selftests/bpf: extend bpf tunnel test with gre Willem de Bruijn
2019-03-20 14:49 ` [PATCH bpf-next 06/13] selftests/bpf: extend bpf tunnel test with tso Willem de Bruijn
2019-03-20 14:49 ` Willem de Bruijn [this message]
2019-03-20 14:49 ` [PATCH bpf-next 08/13] bpf: add bpf_skb_adjust_room flag BPF_F_ADJ_ROOM_FIXED_GSO Willem de Bruijn
2019-03-21 13:42 ` Alan Maguire
2019-03-21 14:00 ` Willem de Bruijn
2019-03-20 14:49 ` [PATCH bpf-next 09/13] bpf: add bpf_skb_adjust_room encap flags Willem de Bruijn
2019-03-20 15:51 ` Alan Maguire
2019-03-20 18:10 ` Willem de Bruijn
2019-03-21 3:13 ` Alexei Starovoitov
2019-03-21 13:25 ` Willem de Bruijn
2019-03-20 14:49 ` [PATCH bpf-next 10/13] bpf: Sync bpf.h to tools Willem de Bruijn
2019-03-20 14:56 ` Soheil Hassas Yeganeh
2019-03-20 14:49 ` [PATCH bpf-next 11/13] selftests/bpf: convert bpf tunnel test to BPF_ADJ_ROOM_MAC Willem de Bruijn
2019-03-20 14:49 ` [PATCH bpf-next 12/13] selftests/bpf: convert bpf tunnel test to BPF_F_ADJ_ROOM_FIXED_GSO Willem de Bruijn
2019-03-20 14:49 ` [PATCH bpf-next 13/13] selftests/bpf: convert bpf tunnel test to encap modes Willem de Bruijn
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