diff options
| -rw-r--r-- | net/ipv4/tcp_probe.c | 194 |
1 files changed, 124 insertions, 70 deletions
diff --git a/net/ipv4/tcp_probe.c b/net/ipv4/tcp_probe.c index d9323df..86624fa 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); |