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authorLawrence Brakmo <brakmo@fb.com>2018-01-25 16:14:07 -0800
committerAlexei Starovoitov <ast@kernel.org>2018-01-25 16:41:13 -0800
commit34d367c59233464dbd1f07445c4665099a7128ec (patch)
tree3d661ded06f00744bc5eabbf0906177649a77fc3 /net/core
parenta33de3973488680def6a900e74ec67ba2bef226c (diff)
downloadlinux-34d367c59233464dbd1f07445c4665099a7128ec.tar.bz2
bpf: Make SOCK_OPS_GET_TCP struct independent
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> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/filter.c20
1 files changed, 10 insertions, 10 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 62e78748d95f..dbb6d2f60680 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;