linux/net/ipv4/tcp_probe.c
Deepa Dinamani b1b270d863 net: ipv4: tcp_probe: Replace timespec with timespec64
TCP probe log timestamps use struct timespec which is
not y2038 safe. Even though timespec might be good enough here
as it is used to represent delta time, the plan is to get rid
of all uses of timespec in the kernel.
Replace with struct timespec64 which is y2038 safe.

Prints still use unsigned long format and type.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-03-01 17:18:44 -05:00

301 lines
7.4 KiB
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;
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)
{
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 = 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_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);