[PATCH net-next 2/3] bpf: add TCP_BPF_RTO_MAX for bpf_setsockopt

[Jason Xing <kerneljasonxing@gmail.com>]

Support bpf_setsockopt() to set the maximum value of RTO for
BPF program.

Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
---
 Documentation/networking/ip-sysctl.rst | 3 ++-
 include/uapi/linux/bpf.h               | 2 ++
 net/core/filter.c                      | 6 ++++++
 tools/include/uapi/linux/bpf.h         | 2 ++
 4 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 054561f8dcae..78eb0959438a 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -1241,7 +1241,8 @@ tcp_rto_min_us - INTEGER
 
 tcp_rto_max_ms - INTEGER
 	Maximal TCP retransmission timeout (in ms).
-	Note that TCP_RTO_MAX_MS socket option has higher precedence.
+	Note that TCP_BPF_RTO_MAX and TCP_RTO_MAX_MS socket option have the
+	higher precedence for configuring this setting.
 
 	When changing tcp_rto_max_ms, it is important to understand
 	that tcp_retries2 might need a change.
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 2acf9b336371..8ab6ef144217 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2868,6 +2868,7 @@ union bpf_attr {
  * 		  **TCP_NODELAY**, **TCP_MAXSEG**, **TCP_WINDOW_CLAMP**,
  * 		  **TCP_THIN_LINEAR_TIMEOUTS**, **TCP_BPF_DELACK_MAX**,
  *		  **TCP_BPF_RTO_MIN**, **TCP_BPF_SOCK_OPS_CB_FLAGS**.
+ *		  **TCP_BPF_RTO_MAX**
  * 		* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
  * 		* **IPPROTO_IPV6**, which supports the following *optname*\ s:
  * 		  **IPV6_TCLASS**, **IPV6_AUTOFLOWLABEL**.
@@ -7091,6 +7092,7 @@ enum {
 	TCP_BPF_SYN_IP		= 1006, /* Copy the IP[46] and TCP header */
 	TCP_BPF_SYN_MAC         = 1007, /* Copy the MAC, IP[46], and TCP header */
 	TCP_BPF_SOCK_OPS_CB_FLAGS = 1008, /* Get or Set TCP sock ops flags */
+	TCP_BPF_RTO_MAX		= 1009, /* Max delay ack in msecs */
 };
 
 enum {
diff --git a/net/core/filter.c b/net/core/filter.c
index 2ec162dd83c4..a21a147e0a86 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5303,6 +5303,12 @@ static int bpf_sol_tcp_setsockopt(struct sock *sk, int optname,
 			return -EINVAL;
 		tp->bpf_sock_ops_cb_flags = val;
 		break;
+	case TCP_BPF_RTO_MAX:
+		if (val > TCP_RTO_MAX_SEC * MSEC_PER_SEC ||
+		    val < TCP_RTO_MAX_MIN_SEC * MSEC_PER_SEC)
+			return -EINVAL;
+		inet_csk(sk)->icsk_rto_max = msecs_to_jiffies(val);
+		break;
 	default:
 		return -EINVAL;
 	}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 2acf9b336371..8ab6ef144217 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -2868,6 +2868,7 @@ union bpf_attr {
  * 		  **TCP_NODELAY**, **TCP_MAXSEG**, **TCP_WINDOW_CLAMP**,
  * 		  **TCP_THIN_LINEAR_TIMEOUTS**, **TCP_BPF_DELACK_MAX**,
  *		  **TCP_BPF_RTO_MIN**, **TCP_BPF_SOCK_OPS_CB_FLAGS**.
+ *		  **TCP_BPF_RTO_MAX**
  * 		* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
  * 		* **IPPROTO_IPV6**, which supports the following *optname*\ s:
  * 		  **IPV6_TCLASS**, **IPV6_AUTOFLOWLABEL**.
@@ -7091,6 +7092,7 @@ enum {
 	TCP_BPF_SYN_IP		= 1006, /* Copy the IP[46] and TCP header */
 	TCP_BPF_SYN_MAC         = 1007, /* Copy the MAC, IP[46], and TCP header */
 	TCP_BPF_SOCK_OPS_CB_FLAGS = 1008, /* Get or Set TCP sock ops flags */
+	TCP_BPF_RTO_MAX		= 1009, /* Max delay ack in msecs */
 };
 
 enum {
-- 
2.43.5