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authorLawrence Brakmo <brakmo@fb.com>2018-01-26 03:14:10 +0300
committerAlexei Starovoitov <ast@kernel.org>2018-01-26 03:41:14 +0300
commitb13d880721729384757f235166068c315326f4a1 (patch)
tree7d117afdbf662f4bc89261885e547053fbed90f7 /include/linux/tcp.h
parentde525be2ca2734865d29c4b67ddd29913b214906 (diff)
downloadlinux-b13d880721729384757f235166068c315326f4a1.tar.xz
bpf: Adds field bpf_sock_ops_cb_flags to tcp_sock
Adds field bpf_sock_ops_cb_flags to tcp_sock and bpf_sock_ops. Its primary use is to determine if there should be calls to sock_ops bpf program at various points in the TCP code. The field is initialized to zero, disabling the calls. A sock_ops BPF program can set it, per connection and as necessary, when the connection is established. It also adds support for reading and writting the field within a sock_ops BPF program. Reading is done by accessing the field directly. However, writing is done through the helper function bpf_sock_ops_cb_flags_set, in order to return an error if a BPF program is trying to set a callback that is not supported in the current kernel (i.e. running an older kernel). The helper function returns 0 if it was able to set all of the bits set in the argument, a positive number containing the bits that could not be set, or -EINVAL if the socket is not a full TCP socket. Examples of where one could call the bpf program: 1) When RTO fires 2) When a packet is retransmitted 3) When the connection terminates 4) When a packet is sent 5) When a packet is received 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/tcp.h')
-rw-r--r--include/linux/tcp.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 4f93f0953c41..8f4c54986f97 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -335,6 +335,17 @@ struct tcp_sock {
int linger2;
+
+/* Sock_ops bpf program related variables */
+#ifdef CONFIG_BPF
+ u8 bpf_sock_ops_cb_flags; /* Control calling BPF programs
+ * values defined in uapi/linux/tcp.h
+ */
+#define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) (TP->bpf_sock_ops_cb_flags & ARG)
+#else
+#define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) 0
+#endif
+
/* Receiver side RTT estimation */
struct {
u32 rtt_us;