Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * 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.

 */

#include <linux/kernel.h>

#include <linux/kprobes.h>

#include <linux/socket.h>

#include <linux/tcp.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 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;

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;

        __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;

        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;

}

static inline int tcp_probe_avail(void)

{

        return bufsize - tcp_probe_used();

}

/*

 * 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,

                               struct tcphdr *th, unsigned 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->dport) == port || ntohs(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();

                        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->ssthresh = tcp_current_ssthresh(sk);

                        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_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 % 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;

        if (!buf || len < 0)

                return -EINVAL;

        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;

                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);

                /* 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 cnt == 0 ? error : cnt;

}

static const struct file_operations tcpprobe_fops = {

        .owner   = THIS_MODULE,

        .open    = tcpprobe_open,

        .read    = tcpprobe_read,

};

static __init int tcpprobe_init(void)

{

        int ret = -ENOMEM;

        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(&init_net, procname, S_IRUSR, &tcpprobe_fops))

                goto err0;

        ret = register_jprobe(&tcp_jprobe);

        if (ret)

                goto err1;

        pr_info("TCP probe registered (port=%d)\n", port);

        return 0;

 err1:

        proc_net_remove(&init_net, procname);

 err0:

        kfree(tcp_probe.log);

        return ret;

}

module_init(tcpprobe_init);

static __exit void tcpprobe_exit(void)

{

        proc_net_remove(&init_net, procname);

        unregister_jprobe(&tcp_jprobe);

        kfree(tcp_probe.log);

}

module_exit(tcpprobe_exit);