[PATCH net-next v6 2/6] net: tcp: Remove TCP probe module

[Masami Hiramatsu]

Remove TCP probe module since jprobe has been deprecated.
That function is now replaced by tcp/tcp_probe trace-event.
You can use it via ftrace or perftools.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
 net/Kconfig          |   17 ---
 net/ipv4/Makefile    |    1 
 net/ipv4/tcp_probe.c |  301 --------------------------------------------------
 3 files changed, 319 deletions(-)
 delete mode 100644 net/ipv4/tcp_probe.c

diff --git a/net/Kconfig b/net/Kconfig
index 9dba2715919d..efe930db3c08 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -336,23 +336,6 @@ config NET_PKTGEN
 	  To compile this code as a module, choose M here: the
 	  module will be called pktgen.
 
-config NET_TCPPROBE
-	tristate "TCP connection probing"
-	depends on INET && PROC_FS && KPROBES
-	---help---
-	This module allows for capturing the changes to TCP connection
-	state in response to incoming packets. It is used for debugging
-	TCP congestion avoidance modules. If you don't understand
-	what was just said, you don't need it: say N.
-
-	Documentation on how to use TCP connection probing can be found
-	at:
-	
-	  http://www.linuxfoundation.org/collaborate/workgroups/networking/tcpprobe
-
-	To compile this code as a module, choose M here: the
-	module will be called tcp_probe.
-
 config NET_DROP_MONITOR
 	tristate "Network packet drop alerting service"
 	depends on INET && TRACEPOINTS
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index c6c8ad1d4b6d..47a0a6649a9d 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -43,7 +43,6 @@ obj-$(CONFIG_INET_DIAG) += inet_diag.o
 obj-$(CONFIG_INET_TCP_DIAG) += tcp_diag.o
 obj-$(CONFIG_INET_UDP_DIAG) += udp_diag.o
 obj-$(CONFIG_INET_RAW_DIAG) += raw_diag.o
-obj-$(CONFIG_NET_TCPPROBE) += tcp_probe.o
 obj-$(CONFIG_TCP_CONG_BBR) += tcp_bbr.o
 obj-$(CONFIG_TCP_CONG_BIC) += tcp_bic.o
 obj-$(CONFIG_TCP_CONG_CDG) += tcp_cdg.o
diff --git a/net/ipv4/tcp_probe.c b/net/ipv4/tcp_probe.c
deleted file mode 100644
index 697f4c67b2e3..000000000000
--- a/net/ipv4/tcp_probe.c
+++ /dev/null
@@ -1,301 +0,0 @@
-/*
- * tcpprobe - Observe the TCP flow with kprobes.
- *
- * The idea for this came from Werner Almesberger's umlsim
- * Copyright (C) 2004, Stephen Hemminger <shemminger@xxxxxxxx>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/kernel.h>
-#include <linux/kprobes.h>
-#include <linux/socket.h>
-#include <linux/tcp.h>
-#include <linux/slab.h>
-#include <linux/proc_fs.h>
-#include <linux/module.h>
-#include <linux/ktime.h>
-#include <linux/time.h>
-#include <net/net_namespace.h>
-
-#include <net/tcp.h>
-
-MODULE_AUTHOR("Stephen Hemminger <shemminger@xxxxxxxxxxxxxxxxxxxx>");
-MODULE_DESCRIPTION("TCP cwnd snooper");
-MODULE_LICENSE("GPL");
-MODULE_VERSION("1.1");
-
-static int port __read_mostly;
-MODULE_PARM_DESC(port, "Port to match (0=all)");
-module_param(port, int, 0);
-
-static unsigned int bufsize __read_mostly = 4096;
-MODULE_PARM_DESC(bufsize, "Log buffer size in packets (4096)");
-module_param(bufsize, uint, 0);
-
-static unsigned int fwmark __read_mostly;
-MODULE_PARM_DESC(fwmark, "skb mark to match (0=no mark)");
-module_param(fwmark, uint, 0);
-
-static int full __read_mostly;
-MODULE_PARM_DESC(full, "Full log (1=every ack packet received,  0=only cwnd changes)");
-module_param(full, int, 0);
-
-static const char procname[] = "tcpprobe";
-
-struct tcp_log {
-	ktime_t tstamp;
-	union {
-		struct sockaddr		raw;
-		struct sockaddr_in	v4;
-		struct sockaddr_in6	v6;
-	}	src, dst;
-	u16	length;
-	u32	snd_nxt;
-	u32	snd_una;
-	u32	snd_wnd;
-	u32	rcv_wnd;
-	u32	snd_cwnd;
-	u32	ssthresh;
-	u32	srtt;
-};
-
-static struct {
-	spinlock_t	lock;
-	wait_queue_head_t wait;
-	ktime_t		start;
-	u32		lastcwnd;
-
-	unsigned long	head, tail;
-	struct tcp_log	*log;
-} tcp_probe;
-
-static inline int tcp_probe_used(void)
-{
-	return (tcp_probe.head - tcp_probe.tail) & (bufsize - 1);
-}
-
-static inline int tcp_probe_avail(void)
-{
-	return bufsize - tcp_probe_used() - 1;
-}
-
-#define tcp_probe_copy_fl_to_si4(inet, si4, mem)		\
-	do {							\
-		si4.sin_family = AF_INET;			\
-		si4.sin_port = inet->inet_##mem##port;		\
-		si4.sin_addr.s_addr = inet->inet_##mem##addr;	\
-	} while (0)						\
-
-/*
- * Hook inserted to be called before each receive packet.
- * Note: arguments must match tcp_rcv_established()!
- */
-static void jtcp_rcv_established(struct sock *sk, struct sk_buff *skb,
-				 const struct tcphdr *th)
-{
-	unsigned int len = skb->len;
-	const struct tcp_sock *tp = tcp_sk(sk);
-	const struct inet_sock *inet = inet_sk(sk);
-
-	/* Only update if port or skb mark matches */
-	if (((port == 0 && fwmark == 0) ||
-	     ntohs(inet->inet_dport) == port ||
-	     ntohs(inet->inet_sport) == port ||
-	     (fwmark > 0 && skb->mark == fwmark)) &&
-	    (full || tp->snd_cwnd != tcp_probe.lastcwnd)) {
-
-		spin_lock(&tcp_probe.lock);
-		/* If log fills, just silently drop */
-		if (tcp_probe_avail() > 1) {
-			struct tcp_log *p = tcp_probe.log + tcp_probe.head;
-
-			p->tstamp = ktime_get();
-			switch (sk->sk_family) {
-			case AF_INET:
-				tcp_probe_copy_fl_to_si4(inet, p->src.v4, s);
-				tcp_probe_copy_fl_to_si4(inet, p->dst.v4, d);
-				break;
-			case AF_INET6:
-				memset(&p->src.v6, 0, sizeof(p->src.v6));
-				memset(&p->dst.v6, 0, sizeof(p->dst.v6));
-#if IS_ENABLED(CONFIG_IPV6)
-				p->src.v6.sin6_family = AF_INET6;
-				p->src.v6.sin6_port = inet->inet_sport;
-				p->src.v6.sin6_addr = inet6_sk(sk)->saddr;
-
-				p->dst.v6.sin6_family = AF_INET6;
-				p->dst.v6.sin6_port = inet->inet_dport;
-				p->dst.v6.sin6_addr = sk->sk_v6_daddr;
-#endif
-				break;
-			default:
-				BUG();
-			}
-
-			p->length = len;
-			p->snd_nxt = tp->snd_nxt;
-			p->snd_una = tp->snd_una;
-			p->snd_cwnd = tp->snd_cwnd;
-			p->snd_wnd = tp->snd_wnd;
-			p->rcv_wnd = tp->rcv_wnd;
-			p->ssthresh = tcp_current_ssthresh(sk);
-			p->srtt = tp->srtt_us >> 3;
-
-			tcp_probe.head = (tcp_probe.head + 1) & (bufsize - 1);
-		}
-		tcp_probe.lastcwnd = tp->snd_cwnd;
-		spin_unlock(&tcp_probe.lock);
-
-		wake_up(&tcp_probe.wait);
-	}
-
-	jprobe_return();
-}
-
-static struct jprobe tcp_jprobe = {
-	.kp = {
-		.symbol_name	= "tcp_rcv_established",
-	},
-	.entry	= jtcp_rcv_established,
-};
-
-static int tcpprobe_open(struct inode *inode, struct file *file)
-{
-	/* Reset (empty) log */
-	spin_lock_bh(&tcp_probe.lock);
-	tcp_probe.head = tcp_probe.tail = 0;
-	tcp_probe.start = ktime_get();
-	spin_unlock_bh(&tcp_probe.lock);
-
-	return 0;
-}
-
-static int tcpprobe_sprint(char *tbuf, int n)
-{
-	const struct tcp_log *p
-		= tcp_probe.log + tcp_probe.tail;
-	struct timespec64 ts
-		= ktime_to_timespec64(ktime_sub(p->tstamp, tcp_probe.start));
-
-	return scnprintf(tbuf, n,
-			"%lu.%09lu %pISpc %pISpc %d %#x %#x %u %u %u %u %u\n",
-			(unsigned long)ts.tv_sec,
-			(unsigned long)ts.tv_nsec,
-			&p->src, &p->dst, p->length, p->snd_nxt, p->snd_una,
-			p->snd_cwnd, p->ssthresh, p->snd_wnd, p->srtt, p->rcv_wnd);
-}
-
-static ssize_t tcpprobe_read(struct file *file, char __user *buf,
-			     size_t len, loff_t *ppos)
-{
-	int error = 0;
-	size_t cnt = 0;
-
-	if (!buf)
-		return -EINVAL;
-
-	while (cnt < len) {
-		char tbuf[256];
-		int width;
-
-		/* Wait for data in buffer */
-		error = wait_event_interruptible(tcp_probe.wait,
-						 tcp_probe_used() > 0);
-		if (error)
-			break;
-
-		spin_lock_bh(&tcp_probe.lock);
-		if (tcp_probe.head == tcp_probe.tail) {
-			/* multiple readers race? */
-			spin_unlock_bh(&tcp_probe.lock);
-			continue;
-		}
-
-		width = tcpprobe_sprint(tbuf, sizeof(tbuf));
-
-		if (cnt + width < len)
-			tcp_probe.tail = (tcp_probe.tail + 1) & (bufsize - 1);
-
-		spin_unlock_bh(&tcp_probe.lock);
-
-		/* if record greater than space available
-		   return partial buffer (so far) */
-		if (cnt + width >= len)
-			break;
-
-		if (copy_to_user(buf + cnt, tbuf, width))
-			return -EFAULT;
-		cnt += width;
-	}
-
-	return cnt == 0 ? error : cnt;
-}
-
-static const struct file_operations tcpprobe_fops = {
-	.owner	 = THIS_MODULE,
-	.open	 = tcpprobe_open,
-	.read    = tcpprobe_read,
-	.llseek  = noop_llseek,
-};
-
-static __init int tcpprobe_init(void)
-{
-	int ret = -ENOMEM;
-
-	/* Warning: if the function signature of tcp_rcv_established,
-	 * has been changed, you also have to change the signature of
-	 * jtcp_rcv_established, otherwise you end up right here!
-	 */
-	BUILD_BUG_ON(__same_type(tcp_rcv_established,
-				 jtcp_rcv_established) == 0);
-
-	init_waitqueue_head(&tcp_probe.wait);
-	spin_lock_init(&tcp_probe.lock);
-
-	if (bufsize == 0)
-		return -EINVAL;
-
-	bufsize = roundup_pow_of_two(bufsize);
-	tcp_probe.log = kcalloc(bufsize, sizeof(struct tcp_log), GFP_KERNEL);
-	if (!tcp_probe.log)
-		goto err0;
-
-	if (!proc_create(procname, S_IRUSR, init_net.proc_net, &tcpprobe_fops))
-		goto err0;
-
-	ret = register_jprobe(&tcp_jprobe);
-	if (ret)
-		goto err1;
-
-	pr_info("probe registered (port=%d/fwmark=%u) bufsize=%u\n",
-		port, fwmark, bufsize);
-	return 0;
- err1:
-	remove_proc_entry(procname, init_net.proc_net);
- err0:
-	kfree(tcp_probe.log);
-	return ret;
-}
-module_init(tcpprobe_init);
-
-static __exit void tcpprobe_exit(void)
-{
-	remove_proc_entry(procname, init_net.proc_net);
-	unregister_jprobe(&tcp_jprobe);
-	kfree(tcp_probe.log);
-}
-module_exit(tcpprobe_exit);