From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org, daniel@iogearbox.net, ast@kernel.org,
Willem de Bruijn <willemb@google.com>
Subject: [PATCH bpf-next 1/3] bpf: add gso_size to __sk_buff
Date: Tue, 3 Mar 2020 15:05:01 -0500 [thread overview]
Message-ID: <20200303200503.226217-2-willemdebruijn.kernel@gmail.com> (raw)
In-Reply-To: <20200303200503.226217-1-willemdebruijn.kernel@gmail.com>
From: Willem de Bruijn <willemb@google.com>
BPF programs may want to know whether an skb is gso. The canonical
answer is skb_is_gso(skb), which tests that gso_size != 0.
Expose this field in the same manner as gso_segs. That field itself
is not a sufficient signal, as the comment in skb_shared_info makes
clear: gso_segs may be zero, e.g., from dodgy sources.
Also prepare net/bpf/test_run for upcoming BPF_PROG_TEST_RUN tests
of the feature.
Signed-off-by: Willem de Bruijn <willemb@google.com>
---
include/uapi/linux/bpf.h | 1 +
net/bpf/test_run.c | 7 +++++++
net/core/filter.c | 44 +++++++++++++++++++++++++++-------------
3 files changed, 38 insertions(+), 14 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 8e98ced0963b..180337fae97e 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3176,6 +3176,7 @@ struct __sk_buff {
__u32 wire_len;
__u32 gso_segs;
__bpf_md_ptr(struct bpf_sock *, sk);
+ __u32 gso_size;
};
struct bpf_tunnel_key {
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 562443f94133..1cd7a1c2f8b2 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -277,6 +277,12 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb)
/* gso_segs is allowed */
if (!range_is_zero(__skb, offsetofend(struct __sk_buff, gso_segs),
+ offsetof(struct __sk_buff, gso_size)))
+ return -EINVAL;
+
+ /* gso_size is allowed */
+
+ if (!range_is_zero(__skb, offsetofend(struct __sk_buff, gso_size),
sizeof(struct __sk_buff)))
return -EINVAL;
@@ -297,6 +303,7 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb)
if (__skb->gso_segs > GSO_MAX_SEGS)
return -EINVAL;
skb_shinfo(skb)->gso_segs = __skb->gso_segs;
+ skb_shinfo(skb)->gso_size = __skb->gso_size;
return 0;
}
diff --git a/net/core/filter.c b/net/core/filter.c
index 4a08c9fb2be7..cd0a532db4e7 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7139,6 +7139,27 @@ static u32 flow_dissector_convert_ctx_access(enum bpf_access_type type,
return insn - insn_buf;
}
+static struct bpf_insn *bpf_convert_shinfo_access(const struct bpf_insn *si,
+ struct bpf_insn *insn)
+{
+ /* si->dst_reg = skb_shinfo(SKB); */
+#ifdef NET_SKBUFF_DATA_USES_OFFSET
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, end),
+ BPF_REG_AX, si->src_reg,
+ offsetof(struct sk_buff, end));
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, head),
+ si->dst_reg, si->src_reg,
+ offsetof(struct sk_buff, head));
+ *insn++ = BPF_ALU64_REG(BPF_ADD, si->dst_reg, BPF_REG_AX);
+#else
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, end),
+ si->dst_reg, si->src_reg,
+ offsetof(struct sk_buff, end));
+#endif
+
+ return insn;
+}
+
static u32 bpf_convert_ctx_access(enum bpf_access_type type,
const struct bpf_insn *si,
struct bpf_insn *insn_buf,
@@ -7461,26 +7482,21 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
break;
case offsetof(struct __sk_buff, gso_segs):
- /* si->dst_reg = skb_shinfo(SKB); */
-#ifdef NET_SKBUFF_DATA_USES_OFFSET
- *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, end),
- BPF_REG_AX, si->src_reg,
- offsetof(struct sk_buff, end));
- *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, head),
- si->dst_reg, si->src_reg,
- offsetof(struct sk_buff, head));
- *insn++ = BPF_ALU64_REG(BPF_ADD, si->dst_reg, BPF_REG_AX);
-#else
- *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, end),
- si->dst_reg, si->src_reg,
- offsetof(struct sk_buff, end));
-#endif
+ insn = bpf_convert_shinfo_access(si, insn);
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct skb_shared_info, gso_segs),
si->dst_reg, si->dst_reg,
bpf_target_off(struct skb_shared_info,
gso_segs, 2,
target_size));
break;
+ case offsetof(struct __sk_buff, gso_size):
+ insn = bpf_convert_shinfo_access(si, insn);
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct skb_shared_info, gso_size),
+ si->dst_reg, si->dst_reg,
+ bpf_target_off(struct skb_shared_info,
+ gso_size, 2,
+ target_size));
+ break;
case offsetof(struct __sk_buff, wire_len):
BUILD_BUG_ON(sizeof_field(struct qdisc_skb_cb, pkt_len) != 4);
--
2.25.0.265.gbab2e86ba0-goog
next prev parent reply other threads:[~2020-03-03 20:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-03 20:05 [PATCH bpf-next 0/3] add gso_size to __sk_buff Willem de Bruijn
2020-03-03 20:05 ` Willem de Bruijn [this message]
2020-03-03 20:05 ` [PATCH bpf-next 2/3] bpf: Sync uapi bpf.h to tools/ Willem de Bruijn
2020-03-03 20:05 ` [PATCH bpf-next 3/3] selftests/bpf: test new __sk_buff field gso_size Willem de Bruijn
2020-03-03 22:56 ` [PATCH bpf-next 0/3] add gso_size to __sk_buff Petar Penkov
2020-03-04 0:31 ` Alexei Starovoitov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200303200503.226217-2-willemdebruijn.kernel@gmail.com \
--to=willemdebruijn.kernel@gmail.com \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=netdev@vger.kernel.org \
--cc=willemb@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).