[deliverable/linux.git] / net / ipv4 / tcp_probe.c

/*
 * tcpprobe - Observe the TCP flow with kprobes.
 *
 * The idea for this came from Werner Almesberger's umlsim
 * Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
 *
 * 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@linux-foundation.org>");
MODULE_DESCRIPTION("TCP cwnd snooper");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.1");

static int port __read_mostly = 0;
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 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)						\

#if IS_ENABLED(CONFIG_IPV6)
#define tcp_probe_copy_fl_to_si6(inet, si6, mem)		\
	do {							\
		struct ipv6_pinfo *pi6 = inet->pinet6;		\
		si6.sin6_family = AF_INET6;			\
		si6.sin6_port = inet->inet_##mem##port;		\
		si6.sin6_addr = pi6->mem##addr;			\
		si6.sin6_flowinfo = 0; /* No need here. */	\
		si6.sin6_scope_id = 0;	/* No need here. */	\
	} while (0)
#else
#define tcp_probe_copy_fl_to_si6(fl, si6, mem)			\
	do {							\
		memset(&si6, 0, sizeof(si6));			\
	} while (0)
#endif

/*
 * Hook inserted to be called before each receive packet.
 * Note: arguments must match tcp_rcv_established()!
 */
static int jtcp_rcv_established(struct sock *sk, struct sk_buff *skb,
				const struct tcphdr *th, unsigned int len)
{
	const struct tcp_sock *tp = tcp_sk(sk);
	const struct inet_sock *inet = inet_sk(sk);

	/* Only update if port matches */
	if ((port == 0 || ntohs(inet->inet_dport) == port ||
	     ntohs(inet->inet_sport) == port) &&
	    (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:
				tcp_probe_copy_fl_to_si6(inet, p->src.v6, s);
				tcp_probe_copy_fl_to_si6(inet, p->dst.v6, d);
				break;
			default:
				BUG();
			}

			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->rcv_wnd = tp->rcv_wnd;
			p->ssthresh = tcp_current_ssthresh(sk);
			p->srtt = tp->srtt >> 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();
	return 0;
}

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 timespec tv
		= ktime_to_timespec(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) tv.tv_sec,
			(unsigned long) tv.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[164];
		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) bufsize=%u\n", port, 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);
Commit	Line	Data
a42e9d6c SH	1	/*
	2	* tcpprobe - Observe the TCP flow with kprobes.
	3	*
	4	* The idea for this came from Werner Almesberger's umlsim
	5	* Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
662ad4f8	9	* the Free Software Foundation; either version 2 of the License.
a42e9d6c SH	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	19	*/
	20
afd46503 JP	21	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
afd46503 JP	22
a42e9d6c SH	23	#include <linux/kernel.h>
	24	#include <linux/kprobes.h>
	25	#include <linux/socket.h>
	26	#include <linux/tcp.h>
5a0e3ad6	27	#include <linux/slab.h>
a42e9d6c SH	28	#include <linux/proc_fs.h>
a42e9d6c SH	29	#include <linux/module.h>
85795d64 SH	30	#include <linux/ktime.h>
85795d64 SH	31	#include <linux/time.h>
457c4cbc	32	#include <net/net_namespace.h>
a42e9d6c SH	33
	34	#include <net/tcp.h>
	35
65ebe634	36	MODULE_AUTHOR("Stephen Hemminger <shemminger@linux-foundation.org>");
a42e9d6c SH	37	MODULE_DESCRIPTION("TCP cwnd snooper");
a42e9d6c SH	38	MODULE_LICENSE("GPL");
662ad4f8	39	MODULE_VERSION("1.1");
a42e9d6c	40
85795d64	41	static int port __read_mostly = 0;
a42e9d6c SH	42	MODULE_PARM_DESC(port, "Port to match (0=all)");
	43	module_param(port, int, 0);
	44
f81074f8	45	static unsigned int bufsize __read_mostly = 4096;
662ad4f8	46	MODULE_PARM_DESC(bufsize, "Log buffer size in packets (4096)");
f81074f8	47	module_param(bufsize, uint, 0);
a42e9d6c	48
85795d64 SH	49	static int full __read_mostly;
	50	MODULE_PARM_DESC(full, "Full log (1=every ack packet received, 0=only cwnd changes)");
	51	module_param(full, int, 0);
	52
a42e9d6c SH	53	static const char procname[] = "tcpprobe";
a42e9d6c SH	54
662ad4f8 SH	55	struct tcp_log {
662ad4f8 SH	56	ktime_t tstamp;
f925d0a6 DB	57	union {
	58	struct sockaddr raw;
	59	struct sockaddr_in v4;
	60	struct sockaddr_in6 v6;
	61	} src, dst;
662ad4f8 SH	62	u16 length;
	63	u32 snd_nxt;
	64	u32 snd_una;
	65	u32 snd_wnd;
b4c1c1d0	66	u32 rcv_wnd;
662ad4f8 SH	67	u32 snd_cwnd;
	68	u32 ssthresh;
	69	u32 srtt;
	70	};
	71
	72	static struct {
85795d64	73	spinlock_t lock;
a42e9d6c	74	wait_queue_head_t wait;
85795d64 SH	75	ktime_t start;
85795d64 SH	76	u32 lastcwnd;
a42e9d6c	77
662ad4f8 SH	78	unsigned long head, tail;
	79	struct tcp_log *log;
	80	} tcp_probe;
	81
14a49e1f	82
662ad4f8	83	static inline int tcp_probe_used(void)
a42e9d6c	84	{
f81074f8	85	return (tcp_probe.head - tcp_probe.tail) & (bufsize - 1);
662ad4f8 SH	86	}
	87
	88	static inline int tcp_probe_avail(void)
	89	{
f81074f8	90	return bufsize - tcp_probe_used() - 1;
14a49e1f	91	}
a42e9d6c	92
f925d0a6 DB	93	#define tcp_probe_copy_fl_to_si4(inet, si4, mem) \
	94	do { \
	95	si4.sin_family = AF_INET; \
	96	si4.sin_port = inet->inet_##mem##port; \
	97	si4.sin_addr.s_addr = inet->inet_##mem##addr; \
	98	} while (0) \
	99
	100	#if IS_ENABLED(CONFIG_IPV6)
	101	#define tcp_probe_copy_fl_to_si6(inet, si6, mem) \
	102	do { \
	103	struct ipv6_pinfo *pi6 = inet->pinet6; \
	104	si6.sin6_family = AF_INET6; \
	105	si6.sin6_port = inet->inet_##mem##port; \
	106	si6.sin6_addr = pi6->mem##addr; \
	107	si6.sin6_flowinfo = 0; /* No need here. */ \
	108	si6.sin6_scope_id = 0; /* No need here. */ \
	109	} while (0)
	110	#else
	111	#define tcp_probe_copy_fl_to_si6(fl, si6, mem) \
	112	do { \
	113	memset(&si6, 0, sizeof(si6)); \
	114	} while (0)
	115	#endif
	116
85795d64 SH	117	/*
	118	* Hook inserted to be called before each receive packet.
	119	* Note: arguments must match tcp_rcv_established()!
	120	*/
	121	static int jtcp_rcv_established(struct sock sk, struct sk_buff skb,
d8cdeda6	122	const struct tcphdr *th, unsigned int len)
a42e9d6c SH	123	{
	124	const struct tcp_sock *tp = tcp_sk(sk);
	125	const struct inet_sock *inet = inet_sk(sk);
	126
85795d64	127	/* Only update if port matches */
c720c7e8	128	if ((port == 0 \|\| ntohs(inet->inet_dport) == port \|\|
9d4fb27d JP	129	ntohs(inet->inet_sport) == port) &&
9d4fb27d JP	130	(full \|\| tp->snd_cwnd != tcp_probe.lastcwnd)) {
662ad4f8 SH	131
	132	spin_lock(&tcp_probe.lock);
	133	/* If log fills, just silently drop */
	134	if (tcp_probe_avail() > 1) {
	135	struct tcp_log *p = tcp_probe.log + tcp_probe.head;
	136
	137	p->tstamp = ktime_get();
f925d0a6 DB	138	switch (sk->sk_family) {
	139	case AF_INET:
	140	tcp_probe_copy_fl_to_si4(inet, p->src.v4, s);
	141	tcp_probe_copy_fl_to_si4(inet, p->dst.v4, d);
	142	break;
	143	case AF_INET6:
	144	tcp_probe_copy_fl_to_si6(inet, p->src.v6, s);
	145	tcp_probe_copy_fl_to_si6(inet, p->dst.v6, d);
	146	break;
	147	default:
	148	BUG();
	149	}
	150
662ad4f8 SH	151	p->length = skb->len;
	152	p->snd_nxt = tp->snd_nxt;
	153	p->snd_una = tp->snd_una;
	154	p->snd_cwnd = tp->snd_cwnd;
	155	p->snd_wnd = tp->snd_wnd;
b4c1c1d0	156	p->rcv_wnd = tp->rcv_wnd;
b3b0b681	157	p->ssthresh = tcp_current_ssthresh(sk);
662ad4f8 SH	158	p->srtt = tp->srtt >> 3;
662ad4f8 SH	159
f81074f8	160	tcp_probe.head = (tcp_probe.head + 1) & (bufsize - 1);
662ad4f8 SH	161	}
	162	tcp_probe.lastcwnd = tp->snd_cwnd;
	163	spin_unlock(&tcp_probe.lock);
	164
	165	wake_up(&tcp_probe.wait);
a42e9d6c SH	166	}
	167
	168	jprobe_return();
	169	return 0;
	170	}
	171
662ad4f8	172	static struct jprobe tcp_jprobe = {
3a872d89	173	.kp = {
85795d64	174	.symbol_name = "tcp_rcv_established",
3a872d89	175	},
9e367d85	176	.entry = jtcp_rcv_established,
a42e9d6c SH	177	};
a42e9d6c SH	178
5e73ea1a	179	static int tcpprobe_open(struct inode inode, struct file file)
a42e9d6c	180	{
662ad4f8 SH	181	/* Reset (empty) log */
	182	spin_lock_bh(&tcp_probe.lock);
	183	tcp_probe.head = tcp_probe.tail = 0;
	184	tcp_probe.start = ktime_get();
	185	spin_unlock_bh(&tcp_probe.lock);
	186
a42e9d6c SH	187	return 0;
	188	}
	189
662ad4f8 SH	190	static int tcpprobe_sprint(char *tbuf, int n)
	191	{
	192	const struct tcp_log *p
f81074f8	193	= tcp_probe.log + tcp_probe.tail;
662ad4f8 SH	194	struct timespec tv
	195	= ktime_to_timespec(ktime_sub(p->tstamp, tcp_probe.start));
	196
dda0b386	197	return scnprintf(tbuf, n,
f925d0a6	198	"%lu.%09lu %pISpc %pISpc %d %#x %#x %u %u %u %u %u\n",
662ad4f8 SH	199	(unsigned long) tv.tv_sec,
662ad4f8 SH	200	(unsigned long) tv.tv_nsec,
f925d0a6	201	&p->src, &p->dst, p->length, p->snd_nxt, p->snd_una,
b4c1c1d0	202	p->snd_cwnd, p->ssthresh, p->snd_wnd, p->srtt, p->rcv_wnd);
662ad4f8 SH	203	}
662ad4f8 SH	204
a42e9d6c SH	205	static ssize_t tcpprobe_read(struct file file, char __user buf,
	206	size_t len, loff_t *ppos)
	207	{
a2025b8b RK	208	int error = 0;
a2025b8b RK	209	size_t cnt = 0;
a42e9d6c	210
a2025b8b	211	if (!buf)
a42e9d6c SH	212	return -EINVAL;
a42e9d6c SH	213
662ad4f8	214	while (cnt < len) {
dda0b386	215	char tbuf[164];
662ad4f8 SH	216	int width;
	217
	218	/* Wait for data in buffer */
	219	error = wait_event_interruptible(tcp_probe.wait,
	220	tcp_probe_used() > 0);
	221	if (error)
	222	break;
a42e9d6c	223
662ad4f8 SH	224	spin_lock_bh(&tcp_probe.lock);
	225	if (tcp_probe.head == tcp_probe.tail) {
	226	/* multiple readers race? */
	227	spin_unlock_bh(&tcp_probe.lock);
	228	continue;
	229	}
a42e9d6c	230
662ad4f8	231	width = tcpprobe_sprint(tbuf, sizeof(tbuf));
a42e9d6c	232
8d390efd	233	if (cnt + width < len)
f81074f8	234	tcp_probe.tail = (tcp_probe.tail + 1) & (bufsize - 1);
a42e9d6c	235
662ad4f8 SH	236	spin_unlock_bh(&tcp_probe.lock);
	237
	238	/* if record greater than space available
	239	return partial buffer (so far) */
8d390efd	240	if (cnt + width >= len)
662ad4f8 SH	241	break;
662ad4f8 SH	242
8d390efd TQ	243	if (copy_to_user(buf + cnt, tbuf, width))
8d390efd TQ	244	return -EFAULT;
662ad4f8 SH	245	cnt += width;
662ad4f8 SH	246	}
a42e9d6c	247
662ad4f8	248	return cnt == 0 ? error : cnt;
a42e9d6c SH	249	}
a42e9d6c SH	250
9a32144e	251	static const struct file_operations tcpprobe_fops = {
a42e9d6c SH	252	.owner = THIS_MODULE,
	253	.open = tcpprobe_open,
	254	.read = tcpprobe_read,
6038f373	255	.llseek = noop_llseek,
a42e9d6c SH	256	};
	257
	258	static __init int tcpprobe_init(void)
	259	{
	260	int ret = -ENOMEM;
	261
d8cdeda6 DB	262	/* Warning: if the function signature of tcp_rcv_established,
	263	* has been changed, you also have to change the signature of
	264	* jtcp_rcv_established, otherwise you end up right here!
	265	*/
	266	BUILD_BUG_ON(__same_type(tcp_rcv_established,
	267	jtcp_rcv_established) == 0);
	268
662ad4f8 SH	269	init_waitqueue_head(&tcp_probe.wait);
	270	spin_lock_init(&tcp_probe.lock);
	271
f81074f8	272	if (bufsize == 0)
662ad4f8 SH	273	return -EINVAL;
662ad4f8 SH	274
f81074f8	275	bufsize = roundup_pow_of_two(bufsize);
3d8ea1fd	276	tcp_probe.log = kcalloc(bufsize, sizeof(struct tcp_log), GFP_KERNEL);
662ad4f8 SH	277	if (!tcp_probe.log)
662ad4f8 SH	278	goto err0;
a42e9d6c	279
d4beaa66	280	if (!proc_create(procname, S_IRUSR, init_net.proc_net, &tcpprobe_fops))
a42e9d6c SH	281	goto err0;
a42e9d6c SH	282
662ad4f8	283	ret = register_jprobe(&tcp_jprobe);
a42e9d6c SH	284	if (ret)
	285	goto err1;
	286
afd46503	287	pr_info("probe registered (port=%d) bufsize=%u\n", port, bufsize);
a42e9d6c SH	288	return 0;
a42e9d6c SH	289	err1:
ece31ffd	290	remove_proc_entry(procname, init_net.proc_net);
a42e9d6c	291	err0:
662ad4f8	292	kfree(tcp_probe.log);
a42e9d6c SH	293	return ret;
	294	}
	295	module_init(tcpprobe_init);
	296
	297	static __exit void tcpprobe_exit(void)
	298	{
ece31ffd	299	remove_proc_entry(procname, init_net.proc_net);
662ad4f8 SH	300	unregister_jprobe(&tcp_jprobe);
662ad4f8 SH	301	kfree(tcp_probe.log);
a42e9d6c SH	302	}
a42e9d6c SH	303	module_exit(tcpprobe_exit);