From: Lawrence Brakmo <brakmo@fb.com>
To: netdev <netdev@vger.kernel.org>
Cc: Kernel Team <kernel-team@fb.com>, Blake Matheny <bmatheny@fb.com>,
Alexei Starovoitov <ast@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Eric Dumazet <eric.dumazet@gmail.com>,
Neal Cardwell <ncardwell@google.com>,
Yuchung Cheng <ycheng@google.com>
Subject: [PATCH bpf-next v9 03/12] bpf: Make SOCK_OPS_GET_TCP struct independent
Date: Wed, 24 Jan 2018 18:37:03 -0800 [thread overview]
Message-ID: <20180125023712.3038949-4-brakmo@fb.com> (raw)
In-Reply-To: <20180125023712.3038949-1-brakmo@fb.com>
Changed SOCK_OPS_GET_TCP to SOCK_OPS_GET_FIELD and added 2
arguments so now it can also work with struct sock fields.
The first argument is the name of the field in the bpf_sock_ops
struct, the 2nd argument is the name of the field in the OBJ struct.
Previous: SOCK_OPS_GET_TCP(FIELD_NAME)
New: SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ)
Where OBJ is either "struct tcp_sock" or "struct sock" (without
quotation). BPF_FIELD is the name of the field in the bpf_sock_ops
struct and OBJ_FIELD is the name of the field in the OBJ struct.
Although the field names are currently the same, the kernel struct names
could change in the future and this change makes it easier to support
that.
Note that adding access to tcp_sock fields in sock_ops programs does
not preclude the tcp_sock fields from being removed as long as we are
willing to do one of the following:
1) Return a fixed value (e.x. 0 or 0xffffffff), or
2) Make the verifier fail if that field is accessed (i.e. program
fails to load) so the user will know that field is no longer
supported.
Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
---
net/core/filter.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/net/core/filter.c b/net/core/filter.c
index 62e7874..dbb6d2f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4469,11 +4469,11 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
is_fullsock));
break;
-/* Helper macro for adding read access to tcp_sock fields. */
-#define SOCK_OPS_GET_TCP(FIELD_NAME) \
+/* Helper macro for adding read access to tcp_sock or sock fields. */
+#define SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ) \
do { \
- BUILD_BUG_ON(FIELD_SIZEOF(struct tcp_sock, FIELD_NAME) > \
- FIELD_SIZEOF(struct bpf_sock_ops, FIELD_NAME)); \
+ BUILD_BUG_ON(FIELD_SIZEOF(OBJ, OBJ_FIELD) > \
+ FIELD_SIZEOF(struct bpf_sock_ops, BPF_FIELD)); \
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF( \
struct bpf_sock_ops_kern, \
is_fullsock), \
@@ -4485,18 +4485,18 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
struct bpf_sock_ops_kern, sk),\
si->dst_reg, si->src_reg, \
offsetof(struct bpf_sock_ops_kern, sk));\
- *insn++ = BPF_LDX_MEM(FIELD_SIZEOF(struct tcp_sock, \
- FIELD_NAME), si->dst_reg, \
- si->dst_reg, \
- offsetof(struct tcp_sock, FIELD_NAME)); \
+ *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(OBJ, \
+ OBJ_FIELD), \
+ si->dst_reg, si->dst_reg, \
+ offsetof(OBJ, OBJ_FIELD)); \
} while (0)
case offsetof(struct bpf_sock_ops, snd_cwnd):
- SOCK_OPS_GET_TCP(snd_cwnd);
+ SOCK_OPS_GET_FIELD(snd_cwnd, snd_cwnd, struct tcp_sock);
break;
case offsetof(struct bpf_sock_ops, srtt_us):
- SOCK_OPS_GET_TCP(srtt_us);
+ SOCK_OPS_GET_FIELD(srtt_us, srtt_us, struct tcp_sock);
break;
}
return insn - insn_buf;
--
2.9.5
next prev parent reply other threads:[~2018-01-25 2:37 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-25 2:37 [PATCH bpf-next v9 00/12] bpf: More sock_ops callbacks Lawrence Brakmo
2018-01-25 2:37 ` [PATCH bpf-next v9 01/12] bpf: Only reply field should be writeable Lawrence Brakmo
2018-01-25 2:37 ` [PATCH bpf-next v9 02/12] bpf: Make SOCK_OPS_GET_TCP size independent Lawrence Brakmo
2018-01-25 2:37 ` Lawrence Brakmo [this message]
2018-01-25 2:37 ` [PATCH bpf-next v9 04/12] bpf: Add write access to tcp_sock and sock fields Lawrence Brakmo
2018-01-25 2:37 ` [PATCH bpf-next v9 05/12] bpf: Support passing args to sock_ops bpf function Lawrence Brakmo
2018-01-25 2:37 ` [PATCH bpf-next v9 06/12] bpf: Adds field bpf_sock_ops_cb_flags to tcp_sock Lawrence Brakmo
2018-01-25 2:37 ` [PATCH bpf-next v9 07/12] bpf: Add sock_ops RTO callback Lawrence Brakmo
2018-01-25 2:37 ` [PATCH bpf-next v9 08/12] bpf: Add support for reading sk_state and more Lawrence Brakmo
2018-01-25 2:37 ` [PATCH bpf-next v9 09/12] bpf: Add sock_ops R/W access to tclass Lawrence Brakmo
2018-01-25 2:37 ` [PATCH bpf-next v9 10/12] bpf: Add BPF_SOCK_OPS_RETRANS_CB Lawrence Brakmo
2018-01-25 2:37 ` [PATCH bpf-next v9 11/12] bpf: Add BPF_SOCK_OPS_STATE_CB Lawrence Brakmo
2018-01-25 2:37 ` [PATCH bpf-next v9 12/12] bpf: add selftest for tcpbpf Lawrence Brakmo
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