bpf: Add BPF_SOCK_OPS_RETRANS_CB
Adds support for calling sock_ops BPF program when there is a
retransmission. Three arguments are used; one for the sequence number,
another for the number of segments retransmitted, and the last one for
the return value of tcp_transmit_skb (0 => success).
Does not include syn-ack retransmissions.
New op: BPF_SOCK_OPS_RETRANS_CB.
Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 46520ea..31c93a0b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1005,7 +1005,8 @@ struct bpf_sock_ops {
/* Definitions for bpf_sock_ops_cb_flags */
#define BPF_SOCK_OPS_RTO_CB_FLAG (1<<0)
-#define BPF_SOCK_OPS_ALL_CB_FLAGS 0x1 /* Mask of all currently
+#define BPF_SOCK_OPS_RETRANS_CB_FLAG (1<<1)
+#define BPF_SOCK_OPS_ALL_CB_FLAGS 0x3 /* Mask of all currently
* supported cb flags
*/
@@ -1047,6 +1048,12 @@ enum {
* Arg2: value of icsk_rto
* Arg3: whether RTO has expired
*/
+ BPF_SOCK_OPS_RETRANS_CB, /* Called when skb is retransmitted.
+ * Arg1: sequence number of 1st byte
+ * Arg2: # segments
+ * Arg3: return value of
+ * tcp_transmit_skb (0 => success)
+ */
};
#define TCP_BPF_IW 1001 /* Set TCP initial congestion window */