From: Lawrence Brakmo <brakmo@fb.com>
Date: Sat, 1 Jul 2017 03:02:47 +0000 (-0700)
Subject: bpf: Add TCP connection BPF callbacks
X-Git-Tag: MMI-PSA29.97-13-9~5285^2~37^2~8
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=9872a4bde31b0b055448e9ac1f4c9ee62d978766;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

bpf: Add TCP connection BPF callbacks

Added callbacks to BPF SOCK_OPS type program before an active
connection is intialized and after a passive or active connection is
established.

The following patch demostrates how they can be used to set send and
receive buffer sizes.

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index dd43b22758d6..2405fe304c98 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -767,6 +767,17 @@ enum {
 					 * window (in packets) or -1 if default
 					 * value should be used
 					 */
+	BPF_SOCK_OPS_TCP_CONNECT_CB,	/* Calls BPF program right before an
+					 * active connection is initialized
+					 */
+	BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB,	/* Calls BPF program when an
+						 * active connection is
+						 * established
+						 */
+	BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB,	/* Calls BPF program when a
+						 * passive connection is
+						 * established
+						 */
 };
 
 #endif /* _UAPI__LINUX_BPF_H__ */
diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index 8b1539efaf38..ce9c7fef200f 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -221,6 +221,7 @@ static struct sock *tcp_fastopen_create_child(struct sock *sk,
 	tcp_init_congestion_control(child);
 	tcp_mtup_init(child);
 	tcp_init_metrics(child);
+	tcp_call_bpf(child, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB);
 	tcp_init_buffer_space(child);
 
 	tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index bcc96654cd7e..664210e5e4a7 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5571,7 +5571,7 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
 	icsk->icsk_af_ops->rebuild_header(sk);
 
 	tcp_init_metrics(sk);
-
+	tcp_call_bpf(sk, BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB);
 	tcp_init_congestion_control(sk);
 
 	/* Prevent spurious tcp_cwnd_restart() on first data
@@ -5977,6 +5977,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
 		} else {
 			/* Make sure socket is routed, for correct metrics. */
 			icsk->icsk_af_ops->rebuild_header(sk);
+			tcp_call_bpf(sk, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB);
 			tcp_init_congestion_control(sk);
 
 			tcp_mtup_init(sk);
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index ef809426b538..33b3e401e812 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -3444,6 +3444,7 @@ int tcp_connect(struct sock *sk)
 	struct sk_buff *buff;
 	int err;
 
+	tcp_call_bpf(sk, BPF_SOCK_OPS_TCP_CONNECT_CB);
 	tcp_connect_init(sk);
 
 	if (unlikely(tp->repair)) {