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authorLawrence Brakmo <brakmo@fb.com>2018-01-26 03:14:08 +0300
committerAlexei Starovoitov <ast@kernel.org>2018-01-26 03:41:14 +0300
commitb73042b8a28e2603ac178295ab96c876ba5a97a1 (patch)
treec3db00b9c7a9b9816bb3392f9fa59f7d8b4a5e49 /include/linux/filter.h
parent34d367c59233464dbd1f07445c4665099a7128ec (diff)
downloadlinux-b73042b8a28e2603ac178295ab96c876ba5a97a1.tar.xz
bpf: Add write access to tcp_sock and sock fields
This patch adds a macro, SOCK_OPS_SET_FIELD, for writing to struct tcp_sock or struct sock fields. This required adding a new field "temp" to struct bpf_sock_ops_kern for temporary storage that is used by sock_ops_convert_ctx_access. It is used to store and recover the contents of a register, so the register can be used to store the address of the sk. Since we cannot overwrite the dst_reg because it contains the pointer to ctx, nor the src_reg since it contains the value we want to store, we need an extra register to contain the address of the sk. Also adds the macro SOCK_OPS_GET_OR_SET_FIELD that calls one of the GET or SET macros depending on the value of the TYPE field. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include/linux/filter.h')
-rw-r--r--include/linux/filter.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 425056c7f96c..daa5a676335f 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1007,6 +1007,15 @@ struct bpf_sock_ops_kern {
u32 replylong[4];
};
u32 is_fullsock;
+ u64 temp; /* temp and everything after is not
+ * initialized to 0 before calling
+ * the BPF program. New fields that
+ * should be initialized to 0 should
+ * be inserted before temp.
+ * temp is scratch storage used by
+ * sock_ops_convert_ctx_access
+ * as temporary storage of a register.
+ */
};
#endif /* __LINUX_FILTER_H__ */