[TCP]: tcp probe wraparound handling and other changes (662ad4f8) · Commits · e / devices / android_kernel_oneplus_sm8150

net/ipv4/tcp_probe.c

+124 −70

Original line number	Original line	Diff line number	Diff line
	@@ -6,8 +6,7 @@
	*		*
	* This program is free software; you can redistribute it and/or modify		* 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		* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or		* the Free Software Foundation; either version 2 of the License.
	* (at your option) any later version.
	*		*
	* This program is distributed in the hope that it will be useful,		* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of		* but WITHOUT ANY WARRANTY; without even the implied warranty of
	@@ -25,23 +24,22 @@
	#include <linux/tcp.h>		#include <linux/tcp.h>
	#include <linux/proc_fs.h>		#include <linux/proc_fs.h>
	#include <linux/module.h>		#include <linux/module.h>
	#include <linux/kfifo.h>
	#include <linux/ktime.h>		#include <linux/ktime.h>
	#include <linux/time.h>		#include <linux/time.h>
	#include <linux/vmalloc.h>

	#include <net/tcp.h>		#include <net/tcp.h>

	MODULE_AUTHOR("Stephen Hemminger <shemminger@linux-foundation.org>");		MODULE_AUTHOR("Stephen Hemminger <shemminger@linux-foundation.org>");
	MODULE_DESCRIPTION("TCP cwnd snooper");		MODULE_DESCRIPTION("TCP cwnd snooper");
	MODULE_LICENSE("GPL");		MODULE_LICENSE("GPL");
			MODULE_VERSION("1.1");

	static int port __read_mostly = 0;		static int port __read_mostly = 0;
	MODULE_PARM_DESC(port, "Port to match (0=all)");		MODULE_PARM_DESC(port, "Port to match (0=all)");
	module_param(port, int, 0);		module_param(port, int, 0);

	static int bufsize __read_mostly = 64*1024;		static int bufsize __read_mostly = 4096;
	MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");		MODULE_PARM_DESC(bufsize, "Log buffer size in packets (4096)");
	module_param(bufsize, int, 0);		module_param(bufsize, int, 0);

	static int full __read_mostly;		static int full __read_mostly;
	@@ -50,39 +48,38 @@ module_param(full, int, 0);

	static const char procname[] = "tcpprobe";		static const char procname[] = "tcpprobe";

	struct {		struct tcp_log {
	struct kfifo *fifo;		ktime_t tstamp;
			__be32 saddr, daddr;
			__be16 sport, dport;
			u16 length;
			u32 snd_nxt;
			u32 snd_una;
			u32 snd_wnd;
			u32 snd_cwnd;
			u32 ssthresh;
			u32 srtt;
			};

			static struct {
	spinlock_t lock;		spinlock_t lock;
	wait_queue_head_t wait;		wait_queue_head_t wait;
	ktime_t start;		ktime_t start;
	u32 lastcwnd;		u32 lastcwnd;
	} tcpw;

	/*		unsigned long head, tail;
	* Print to log with timestamps.		struct tcp_log *log;
	* FIXME: causes an extra copy		} tcp_probe;
	*/
	static void printl(const char *fmt, ...)
	__attribute__ ((format (printf, 1, 2)));		static inline int tcp_probe_used(void)
			{
			return (tcp_probe.head - tcp_probe.tail) % bufsize;
			}

	static void printl(const char *fmt, ...)		static inline int tcp_probe_avail(void)
	{		{
	va_list args;		return bufsize - tcp_probe_used();
	int len;
	struct timespec tv;
	char tbuf[256];

	va_start(args, fmt);
	/* want monotonic time since start of tcp_probe */
	tv = ktime_to_timespec(ktime_sub(ktime_get(), tcpw.start));

	len = sprintf(tbuf, "%lu.%09lu ",
	(unsigned long) tv.tv_sec, (unsigned long) tv.tv_nsec);
	len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args);
	va_end(args);

	kfifo_put(tcpw.fifo, tbuf, len);
	wake_up(&tcpw.wait);
	}		}

	/*		/*
	@@ -97,63 +94,117 @@ static int jtcp_rcv_established(struct sock sk, struct sk_buff skb,

	/* Only update if port matches */		/* Only update if port matches */
	if ((port == 0 \|\| ntohs(inet->dport) == port \|\| ntohs(inet->sport) == port)		if ((port == 0 \|\| ntohs(inet->dport) == port \|\| ntohs(inet->sport) == port)
	&& (full \|\| tp->snd_cwnd != tcpw.lastcwnd)) {		&& (full \|\| tp->snd_cwnd != tcp_probe.lastcwnd)) {
	printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %#x %#x %u %u %u %u\n",
	NIPQUAD(inet->saddr), ntohs(inet->sport),		spin_lock(&tcp_probe.lock);
	NIPQUAD(inet->daddr), ntohs(inet->dport),		/* If log fills, just silently drop */
	skb->len, tp->snd_nxt, tp->snd_una,		if (tcp_probe_avail() > 1) {
	tp->snd_cwnd, tcp_current_ssthresh(sk),		struct tcp_log *p = tcp_probe.log + tcp_probe.head;
	tp->snd_wnd, tp->srtt >> 3);
	tcpw.lastcwnd = tp->snd_cwnd;		p->tstamp = ktime_get();
			p->saddr = inet->saddr;
			p->sport = inet->sport;
			p->daddr = inet->daddr;
			p->dport = inet->dport;
			p->length = skb->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->srtt = tp->srtt >> 3;

			tcp_probe.head = (tcp_probe.head + 1) % bufsize;
			}
			tcp_probe.lastcwnd = tp->snd_cwnd;
			spin_unlock(&tcp_probe.lock);

			wake_up(&tcp_probe.wait);
	}		}

	jprobe_return();		jprobe_return();
	return 0;		return 0;
	}		}

	static struct jprobe tcp_probe = {		static struct jprobe tcp_jprobe = {
	.kp = {		.kp = {
	.symbol_name = "tcp_rcv_established",		.symbol_name = "tcp_rcv_established",
	},		},
	.entry = JPROBE_ENTRY(jtcp_rcv_established),		.entry = JPROBE_ENTRY(jtcp_rcv_established),
	};		};


	static int tcpprobe_open(struct inode * inode, struct file * file)		static int tcpprobe_open(struct inode * inode, struct file * file)
	{		{
	kfifo_reset(tcpw.fifo);		/* Reset (empty) log */
	tcpw.start = ktime_get();		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;		return 0;
	}		}

			static int tcpprobe_sprint(char *tbuf, int n)
			{
			const struct tcp_log *p
			= tcp_probe.log + tcp_probe.tail % bufsize;
			struct timespec tv
			= ktime_to_timespec(ktime_sub(p->tstamp, tcp_probe.start));

			return snprintf(tbuf, n,
			"%lu.%09lu %d.%d.%d.%d:%u %d.%d.%d.%d:%u"
			" %d %#x %#x %u %u %u %u\n",
			(unsigned long) tv.tv_sec,
			(unsigned long) tv.tv_nsec,
			NIPQUAD(p->saddr), ntohs(p->sport),
			NIPQUAD(p->daddr), ntohs(p->dport),
			p->length, p->snd_nxt, p->snd_una,
			p->snd_cwnd, p->ssthresh, p->snd_wnd, p->srtt);
			}

	static ssize_t tcpprobe_read(struct file file, char __user buf,		static ssize_t tcpprobe_read(struct file file, char __user buf,
	size_t len, loff_t *ppos)		size_t len, loff_t *ppos)
	{		{
	int error = 0, cnt = 0;		int error = 0, cnt = 0;
	unsigned char *tbuf;

	if (!buf \|\| len < 0)		if (!buf \|\| len < 0)
	return -EINVAL;		return -EINVAL;

	if (len == 0)		while (cnt < len) {
	return 0;		char tbuf[128];
			int width;
	tbuf = vmalloc(len);
	if (!tbuf)
	return -ENOMEM;

	error = wait_event_interruptible(tcpw.wait,		/* Wait for data in buffer */
	__kfifo_len(tcpw.fifo) != 0);		error = wait_event_interruptible(tcp_probe.wait,
			tcp_probe_used() > 0);
	if (error)		if (error)
	goto out_free;		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 (width < len)
			tcp_probe.tail = (tcp_probe.tail + 1) % bufsize;

			spin_unlock_bh(&tcp_probe.lock);

	cnt = kfifo_get(tcpw.fifo, tbuf, len);		/* if record greater than space available
	error = copy_to_user(buf, tbuf, cnt);		return partial buffer (so far) */
			if (width >= len)
			break;

	out_free:		error = copy_to_user(buf + cnt, tbuf, width);
	vfree(tbuf);		if (error)
			break;
			cnt += width;
			}

	return error ? error : cnt;		return cnt == 0 ? error : cnt;
	}		}

	static const struct file_operations tcpprobe_fops = {		static const struct file_operations tcpprobe_fops = {
	@@ -166,34 +217,37 @@ static __init int tcpprobe_init(void)
	{		{
	int ret = -ENOMEM;		int ret = -ENOMEM;

	init_waitqueue_head(&tcpw.wait);		init_waitqueue_head(&tcp_probe.wait);
	spin_lock_init(&tcpw.lock);		spin_lock_init(&tcp_probe.lock);
	tcpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &tcpw.lock);
	if (IS_ERR(tcpw.fifo))		if (bufsize < 0)
	return PTR_ERR(tcpw.fifo);		return -EINVAL;

			tcp_probe.log = kcalloc(sizeof(struct tcp_log), bufsize, GFP_KERNEL);
			if (!tcp_probe.log)
			goto err0;

	if (!proc_net_fops_create(procname, S_IRUSR, &tcpprobe_fops))		if (!proc_net_fops_create(procname, S_IRUSR, &tcpprobe_fops))
	goto err0;		goto err0;

	ret = register_jprobe(&tcp_probe);		ret = register_jprobe(&tcp_jprobe);
	if (ret)		if (ret)
	goto err1;		goto err1;

	pr_info("TCP watch registered (port=%d)\n", port);		pr_info("TCP probe registered (port=%d)\n", port);
	return 0;		return 0;
	err1:		err1:
	proc_net_remove(procname);		proc_net_remove(procname);
	err0:		err0:
	kfifo_free(tcpw.fifo);		kfree(tcp_probe.log);
	return ret;		return ret;
	}		}
	module_init(tcpprobe_init);		module_init(tcpprobe_init);

	static __exit void tcpprobe_exit(void)		static __exit void tcpprobe_exit(void)
	{		{
	kfifo_free(tcpw.fifo);
	proc_net_remove(procname);		proc_net_remove(procname);
	unregister_jprobe(&tcp_probe);		unregister_jprobe(&tcp_jprobe);
			kfree(tcp_probe.log);
	}		}
	module_exit(tcpprobe_exit);		module_exit(tcpprobe_exit);