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-rw-r--r--net/ipv4/tcp_probe.c194
1 files changed, 124 insertions, 70 deletions
diff --git a/net/ipv4/tcp_probe.c b/net/ipv4/tcp_probe.c
index d9323dfff82..86624fabc4b 100644
--- a/net/ipv4/tcp_probe.c
+++ b/net/ipv4/tcp_probe.c
@@ -6,8 +6,7 @@
*
* 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, or
- * (at your option) any later version.
+ * 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
@@ -25,23 +24,22 @@
#include <linux/tcp.h>
#include <linux/proc_fs.h>
#include <linux/module.h>
-#include <linux/kfifo.h>
#include <linux/ktime.h>
#include <linux/time.h>
-#include <linux/vmalloc.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 int bufsize __read_mostly = 64*1024;
-MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
+static int bufsize __read_mostly = 4096;
+MODULE_PARM_DESC(bufsize, "Log buffer size in packets (4096)");
module_param(bufsize, int, 0);
static int full __read_mostly;
@@ -50,39 +48,38 @@ module_param(full, int, 0);
static const char procname[] = "tcpprobe";
-struct {
- struct kfifo *fifo;
+struct tcp_log {
+ 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;
wait_queue_head_t wait;
ktime_t start;
u32 lastcwnd;
-} tcpw;
-/*
- * Print to log with timestamps.
- * FIXME: causes an extra copy
- */
-static void printl(const char *fmt, ...)
- __attribute__ ((format (printf, 1, 2)));
+ unsigned long head, tail;
+ struct tcp_log *log;
+} tcp_probe;
+
-static void printl(const char *fmt, ...)
+static inline int tcp_probe_used(void)
{
- va_list args;
- 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);
+ return (tcp_probe.head - tcp_probe.tail) % bufsize;
+}
+
+static inline int tcp_probe_avail(void)
+{
+ return bufsize - tcp_probe_used();
}
/*
@@ -97,63 +94,117 @@ static int jtcp_rcv_established(struct sock *sk, struct sk_buff *skb,
/* Only update if port matches */
if ((port == 0 || ntohs(inet->dport) == port || ntohs(inet->sport) == port)
- && (full || tp->snd_cwnd != tcpw.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),
- NIPQUAD(inet->daddr), ntohs(inet->dport),
- skb->len, tp->snd_nxt, tp->snd_una,
- tp->snd_cwnd, tcp_current_ssthresh(sk),
- tp->snd_wnd, tp->srtt >> 3);
- tcpw.lastcwnd = tp->snd_cwnd;
+ && (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();
+ 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();
return 0;
}
-static struct jprobe tcp_probe = {
+static struct jprobe tcp_jprobe = {
.kp = {
.symbol_name = "tcp_rcv_established",
},
.entry = JPROBE_ENTRY(jtcp_rcv_established),
};
-
static int tcpprobe_open(struct inode * inode, struct file * file)
{
- kfifo_reset(tcpw.fifo);
- tcpw.start = ktime_get();
+ /* 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 % 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,
size_t len, loff_t *ppos)
{
int error = 0, cnt = 0;
- unsigned char *tbuf;
if (!buf || len < 0)
return -EINVAL;
- if (len == 0)
- return 0;
+ while (cnt < len) {
+ char tbuf[128];
+ int width;
+
+ /* Wait for data in buffer */
+ error = wait_event_interruptible(tcp_probe.wait,
+ tcp_probe_used() > 0);
+ if (error)
+ break;
- tbuf = vmalloc(len);
- if (!tbuf)
- return -ENOMEM;
+ spin_lock_bh(&tcp_probe.lock);
+ if (tcp_probe.head == tcp_probe.tail) {
+ /* multiple readers race? */
+ spin_unlock_bh(&tcp_probe.lock);
+ continue;
+ }
- error = wait_event_interruptible(tcpw.wait,
- __kfifo_len(tcpw.fifo) != 0);
- if (error)
- goto out_free;
+ width = tcpprobe_sprint(tbuf, sizeof(tbuf));
- cnt = kfifo_get(tcpw.fifo, tbuf, len);
- error = copy_to_user(buf, tbuf, cnt);
+ if (width < len)
+ tcp_probe.tail = (tcp_probe.tail + 1) % bufsize;
-out_free:
- vfree(tbuf);
+ spin_unlock_bh(&tcp_probe.lock);
+
+ /* if record greater than space available
+ return partial buffer (so far) */
+ if (width >= len)
+ break;
+
+ error = copy_to_user(buf + cnt, tbuf, width);
+ if (error)
+ break;
+ cnt += width;
+ }
- return error ? error : cnt;
+ return cnt == 0 ? error : cnt;
}
static const struct file_operations tcpprobe_fops = {
@@ -166,34 +217,37 @@ static __init int tcpprobe_init(void)
{
int ret = -ENOMEM;
- init_waitqueue_head(&tcpw.wait);
- spin_lock_init(&tcpw.lock);
- tcpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &tcpw.lock);
- if (IS_ERR(tcpw.fifo))
- return PTR_ERR(tcpw.fifo);
+ init_waitqueue_head(&tcp_probe.wait);
+ spin_lock_init(&tcp_probe.lock);
+
+ if (bufsize < 0)
+ 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))
goto err0;
- ret = register_jprobe(&tcp_probe);
+ ret = register_jprobe(&tcp_jprobe);
if (ret)
goto err1;
- pr_info("TCP watch registered (port=%d)\n", port);
+ pr_info("TCP probe registered (port=%d)\n", port);
return 0;
err1:
proc_net_remove(procname);
err0:
- kfifo_free(tcpw.fifo);
+ kfree(tcp_probe.log);
return ret;
}
module_init(tcpprobe_init);
static __exit void tcpprobe_exit(void)
{
- kfifo_free(tcpw.fifo);
proc_net_remove(procname);
- unregister_jprobe(&tcp_probe);
-
+ unregister_jprobe(&tcp_jprobe);
+ kfree(tcp_probe.log);
}
module_exit(tcpprobe_exit);
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-01 11:29:34 +0000