alinux: add tcprt framework to kernel

to #26353046

TcpRT: Instrument and Diagnostic Analysis System for Service Quality
of Cloud Databases at Massive Scale in Real-time.

It can also provide information for all request/response services. Such as
HTTP request.

This is the kernel framework for tcprt, more work needs tcprt module
support.

TcpRt module should call tcp_unregitsert_rt before rmmod.

TcpRt hooks will be called when sock init, recv data, send data,
packet acked and socket been destroy. The private data save to
icsk->icsk_tcp_rt_priv.
Reviewed-by: NCambda Zhu <cambda@linux.alibaba.com>
Acked-by: NDust Li <dust.li@linux.alibaba.com>
Signed-off-by: Nxuanzhuo <xuanzhuo@linux.alibaba.com>

MAINTAINERS

@@ -136,6 +136,11 @@ Maintainers List (try to look for most precise areas first)
 
 		-----------------------------------
 
+TCP RT
+M:	xuanzhuo <xuanzhuo@linux.alibaba.com>
+S:	Maintained
+F:	net/ipv4/tcp_rt.c
+
 3C59X NETWORK DRIVER
 M:	Steffen Klassert <klassert@kernel.org>
 L:	netdev@vger.kernel.org

include/net/inet_connection_sock.h

@@ -139,6 +139,11 @@ struct inet_connection_sock {
 	} icsk_mtup;
 	u32			  icsk_user_timeout;
 
+#ifdef CONFIG_TCP_RT
+	const struct tcp_rt_ops  *icsk_tcp_rt_ops;
+	void                     *icsk_tcp_rt_priv;
+#endif
+
 	u64			  icsk_ca_priv[88 / sizeof(u64)];
 #define ICSK_CA_PRIV_SIZE      (11 * sizeof(u64))
 };

include/net/tcp.h

@@ -41,6 +41,7 @@
 #include <net/snmp.h>
 #include <net/ip.h>
 #include <net/tcp_states.h>
+#include <net/tcp_rt.h>
 #include <net/inet_ecn.h>
 #include <net/dst.h>
 

include/net/tcp_rt.h

+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * TcpRT        Instrument and Diagnostic Analysis System for Service Quality
+ *              of Cloud Databases at Massive Scale in Real-time.
+ *
+ *              It can also provide information for all request/response
+ *              services. Such as HTTP request.
+ *
+ *              This is the kernel framework, more work needs tcprt module
+ *              support.
+ */
+#ifndef _TCP_RT_H
+#define _TCP_RT_H
+
+#ifdef CONFIG_TCP_RT
+struct tcp_rt_ops {
+	/*
+	 * initialize private data (required)
+	 *
+	 * ret:
+	 *    0: success alloc private data for this connection.
+	 *   -1: fail alloc private data or not care about this connection.
+	 *       Then this connection will not ref to tcp_rt.
+	 */
+	int (*init)(struct sock *sk);
+
+	/* cleanup private data  (required) */
+	void (*release)(struct sock *sk);
+
+	/* recv data */
+	void  (*recv_data)(struct sock *sk);
+
+	/* send data */
+	void  (*send_data)(struct sock *sk);
+
+	/* hook for packet ack accounting */
+	void (*pkts_acked)(struct sock *sk);
+
+	struct module *owner;
+};
+
+/*
+ * tcp_register_rt() - register tcp_rt ops to kernel
+ * @rt: tcp_rt_ops
+ *
+ * ret:
+ *    -EINVAL: init or release of ops not init.
+ *    -EBUSY: fail to get the moudle.
+ *    -EEXIST: there exists one tcprt.
+ *    0: success
+ */
+
+int tcp_register_rt(const struct tcp_rt_ops *rt);
+
+/*
+ * tcp_unregister_rt() - unregister the tcp_rt ops from kernel.
+ *
+ * After call this, the new connection will no ref to the tcp_rt, but
+ * the old connection still ref to the tcp_rt, you must wait for all
+ * old connection been released, then you can try to rmmod module.
+ * So, this function cannot been called inside the module_exit.
+ * You should call this by such as debugfs. such as:
+ *
+ * ----
+ * static ssize_t tcp_rt_inactive(struct file *file, const char __user *buff,
+ *                size_t count, loff_t *offset)
+ * {
+ *      tcp_unregister_rt(&rt_ops);
+ *      return count;
+ * }
+ *
+ * static struct file_operations fops = {
+ *      .owner      = THIS_MODULE,
+ *      .write      = tcp_rt_inactive,
+ * };
+ *
+ * static int __init rt_register(void)
+ * {
+ *      if (!debugfs_create_file("tcp-rt-no-active", 0600, NULL, NULL, fops)) {
+ *              return -1;
+ *      }
+ *
+ *      ret = tcp_register_rt(&rt_ops);
+ *      if (ret) {
+ *              pr_err("tcp-rt register rt failed!\n");
+ *              tcp_rt_base_released();
+ *              return ret;
+ *      }
+ *
+ *      return 0;
+ * }
+ *
+ * static void __exit rt_unregister(void)
+ * {
+ *      pr_info("tcp-rt: released\n");
+ * }
+ *
+ * module_init(rt_register);
+ * module_exit(rt_unregister);
+ * ----
+ *
+ *  run this cmd before you want to rmmod module:
+ *  echo 0 > /sys/kernel/debug/tcp-rt-no-active
+ *
+ */
+void tcp_unregister_rt(struct tcp_rt_ops *rt);
+void tcp_init_rt(struct sock *sk);
+void tcp_cleanup_rt(struct sock *sk);
+
+#define tcp_rt_call(sk, fun)  \
+	do {                                                        \
+		if (inet_csk(sk)->icsk_tcp_rt_ops &&                \
+				inet_csk(sk)->icsk_tcp_rt_ops->fun) \
+			inet_csk(sk)->icsk_tcp_rt_ops->fun(sk);     \
+	} while (0)
+#else
+#define tcp_cleanup_rt(sk)
+#define tcp_init_rt(sk)
+#define tcp_rt_call(sk, fun)
+#endif
+
+#endif	/* _TCP_RT_H */

net/ipv4/Kconfig

@@ -753,3 +753,16 @@ config TCP_MD5SIG
 	  on the Internet.
 
 	  If unsure, say N.
+
+config TCP_RT
+	bool "TCP RT"
+	default n
+	help
+	  TcpRT: Instrument and Diagnostic Analysis System for Service Quality
+	  of Cloud Databases at Massive Scale in Real-time.
+
+	  It can also provide information for all request/response services. Such as
+	  HTTP request.
+
+	  This is used for account opening kernel framework, more work needs
+	  tcprt module support.

net/ipv4/Makefile

@@ -65,5 +65,7 @@ obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.o
 obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o
 obj-$(CONFIG_NETLABEL) += cipso_ipv4.o
 
+obj-$(CONFIG_TCP_RT) += tcp_rt.o
+
 obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \
 		      xfrm4_output.o xfrm4_protocol.o

net/ipv4/tcp.c

@@ -467,6 +467,7 @@ void tcp_init_transfer(struct sock *sk, int bpf_op)
 	tcp_call_bpf(sk, bpf_op, 0, NULL);
 	tcp_init_congestion_control(sk);
 	tcp_init_buffer_space(sk);
+	tcp_init_rt(sk);
 }
 
 static void tcp_tx_timestamp(struct sock *sk, u16 tsflags)

net/ipv4/tcp_input.c

@@ -677,6 +677,8 @@ static void tcp_event_data_recv(struct sock *sk, struct sk_buff *skb)
 
 	now = tcp_jiffies32;
 
+	tcp_rt_call(sk, recv_data);
+
 	if (!icsk->icsk_ack.ato) {
 		/* The _first_ data packet received, initialize
 		 * delayed ACK engine.
@@ -3217,6 +3219,8 @@ static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack,
 		flag |= FLAG_SET_XMIT_TIMER;  /* set TLP or RTO timer */
 	}
 
+	tcp_rt_call(sk, pkts_acked);
+
 	if (icsk->icsk_ca_ops->pkts_acked) {
 		struct ack_sample sample = { .pkts_acked = pkts_acked,
 					     .rtt_us = sack->rate->rtt_us,

net/ipv4/tcp_ipv4.c

@@ -1971,6 +1971,8 @@ void tcp_v4_destroy_sock(struct sock *sk)
 
 	tcp_cleanup_congestion_control(sk);
 
+	tcp_cleanup_rt(sk);
+
 	tcp_cleanup_ulp(sk);
 
 	/* Cleanup up the write buffer. */

net/ipv4/tcp_output.c

@@ -2406,6 +2406,9 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
 			tcp_schedule_loss_probe(sk, false);
 		is_cwnd_limited |= (tcp_packets_in_flight(tp) >= tp->snd_cwnd);
 		tcp_cwnd_validate(sk, is_cwnd_limited);
+
+		tcp_rt_call(sk, send_data);
+
 		return false;
 	}
 	return !tp->packets_out && !tcp_write_queue_empty(sk);

net/ipv4/tcp_rt.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <net/tcp.h>
+#include <linux/module.h>
+
+static const struct tcp_rt_ops __rcu *tcp_rt;
+static DEFINE_SPINLOCK(tcp_rt_lock);
+
+int tcp_register_rt(const struct tcp_rt_ops *rt)
+{
+	const struct tcp_rt_ops *ort;
+	int ret = 0;
+
+	if (!rt->init || !rt->release) {
+		pr_err("tcp_rt does not implement required ops\n");
+		return -EINVAL;
+	}
+
+	spin_lock(&tcp_rt_lock);
+	ret = try_module_get(rt->owner);
+	if (unlikely(!ret)) {
+		ret = -EBUSY;
+	} else {
+		ort = rcu_dereference_protected(tcp_rt, true);
+		if (ort) {
+			ret = -EEXIST;
+			pr_err("tcp_rt already registered\n");
+			module_put(rt->owner);
+		} else {
+			rcu_assign_pointer(tcp_rt, rt);
+			ret = 0;
+		}
+	}
+	spin_unlock(&tcp_rt_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tcp_register_rt);
+
+void  tcp_unregister_rt(struct tcp_rt_ops *rt)
+{
+	const struct tcp_rt_ops *ort = NULL;
+
+	spin_lock(&tcp_rt_lock);
+	rcu_swap_protected(tcp_rt, ort, true);
+	if (ort)
+		module_put(ort->owner);
+	spin_unlock(&tcp_rt_lock);
+
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(tcp_unregister_rt);
+
+void tcp_init_rt(struct sock *sk)
+{
+	struct inet_connection_sock *icsk = inet_csk(sk);
+	const struct tcp_rt_ops *ops;
+
+	rcu_read_lock();
+	ops = rcu_dereference(tcp_rt);
+	if (ops)
+		if (unlikely(!try_module_get(ops->owner)))
+			ops = NULL;
+	icsk->icsk_tcp_rt_ops = ops;
+	rcu_read_unlock();
+
+	ops = icsk->icsk_tcp_rt_ops;
+
+	if (!ops)
+		return;
+
+	if (ops->init(sk)) {
+		module_put(ops->owner);
+		icsk->icsk_tcp_rt_ops = NULL;
+	}
+}
+
+void tcp_cleanup_rt(struct sock *sk)
+{
+	struct inet_connection_sock *icsk = inet_csk(sk);
+
+	if (icsk->icsk_tcp_rt_ops) {
+		icsk->icsk_tcp_rt_ops->release(sk);
+		module_put(icsk->icsk_tcp_rt_ops->owner);
+		icsk->icsk_tcp_rt_ops = NULL;
+	}
+}