1 files changed, 243 insertions, 0 deletions
diff --git a/net/sctp/probe.c b/net/sctp/probe.c
new file mode 100644
index 000000000..5e68b94ee
--- /dev/null
+++ b/net/sctp/probe.c
@@ -0,0 +1,243 @@
+/*
+ * sctp_probe - Observe the SCTP flow with kprobes.
+ *
+ * The idea for this came from Werner Almesberger's umlsim
+ * Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
+ *
+ * Modified for SCTP from Stephen Hemminger's code
+ * Copyright (C) 2010, Wei Yongjun <yjwei@cn.fujitsu.com>
+ *
+ * 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.
+ *
+ * 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/sctp.h>
+#include <linux/proc_fs.h>
+#include <linux/vmalloc.h>
+#include <linux/module.h>
+#include <linux/kfifo.h>
+#include <linux/time.h>
+#include <net/net_namespace.h>
+
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+
+MODULE_SOFTDEP("pre: sctp");
+MODULE_AUTHOR("Wei Yongjun <yjwei@cn.fujitsu.com>");
+MODULE_DESCRIPTION("SCTP snooper");
+MODULE_LICENSE("GPL");
+
+static int port __read_mostly = 0;
+MODULE_PARM_DESC(port, "Port to match (0=all)");
+module_param(port, int, 0);
+
+static unsigned int fwmark __read_mostly = 0;
+MODULE_PARM_DESC(fwmark, "skb mark to match (0=no mark)");
+module_param(fwmark, uint, 0);
+
+static int bufsize __read_mostly = 64 * 1024;
+MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
+module_param(bufsize, int, 0);
+
+static int full __read_mostly = 1;
+MODULE_PARM_DESC(full, "Full log (1=every ack packet received,  0=only cwnd changes)");
+module_param(full, int, 0);
+
+static const char procname[] = "sctpprobe";
+
+static struct {
+	struct kfifo	  fifo;
+	spinlock_t	  lock;
+	wait_queue_head_t wait;
+	struct timespec	  tstart;
+} sctpw;
+
+static __printf(1, 2) void printl(const char *fmt, ...)
+{
+	va_list args;
+	int len;
+	char tbuf[256];
+
+	va_start(args, fmt);
+	len = vscnprintf(tbuf, sizeof(tbuf), fmt, args);
+	va_end(args);
+
+	kfifo_in_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);
+	wake_up(&sctpw.wait);
+}
+
+static int sctpprobe_open(struct inode *inode, struct file *file)
+{
+	kfifo_reset(&sctpw.fifo);
+	getnstimeofday(&sctpw.tstart);
+
+	return 0;
+}
+
+static ssize_t sctpprobe_read(struct file *file, char __user *buf,
+			      size_t len, loff_t *ppos)
+{
+	int error = 0, cnt = 0;
+	unsigned char *tbuf;
+
+	if (!buf)
+		return -EINVAL;
+
+	if (len == 0)
+		return 0;
+
+	tbuf = vmalloc(len);
+	if (!tbuf)
+		return -ENOMEM;
+
+	error = wait_event_interruptible(sctpw.wait,
+					 kfifo_len(&sctpw.fifo) != 0);
+	if (error)
+		goto out_free;
+
+	cnt = kfifo_out_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);
+	error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;
+
+out_free:
+	vfree(tbuf);
+
+	return error ? error : cnt;
+}
+
+static const struct file_operations sctpprobe_fops = {
+	.owner	= THIS_MODULE,
+	.open	= sctpprobe_open,
+	.read	= sctpprobe_read,
+	.llseek = noop_llseek,
+};
+
+static sctp_disposition_t jsctp_sf_eat_sack(struct net *net,
+					    const struct sctp_endpoint *ep,
+					    const struct sctp_association *asoc,
+					    const sctp_subtype_t type,
+					    void *arg,
+					    sctp_cmd_seq_t *commands)
+{
+	struct sctp_chunk *chunk = arg;
+	struct sk_buff *skb = chunk->skb;
+	struct sctp_transport *sp;
+	static __u32 lcwnd = 0;
+	struct timespec now;
+
+	sp = asoc->peer.primary_path;
+
+	if (((port == 0 && fwmark == 0) ||
+	     asoc->peer.port == port ||
+	     ep->base.bind_addr.port == port ||
+	     (fwmark > 0 && skb->mark == fwmark)) &&
+	    (full || sp->cwnd != lcwnd)) {
+		lcwnd = sp->cwnd;
+
+		getnstimeofday(&now);
+		now = timespec_sub(now, sctpw.tstart);
+
+		printl("%lu.%06lu ", (unsigned long) now.tv_sec,
+		       (unsigned long) now.tv_nsec / NSEC_PER_USEC);
+
+		printl("%p %5d %5d %5d %8d %5d ", asoc,
+		       ep->base.bind_addr.port, asoc->peer.port,
+		       asoc->pathmtu, asoc->peer.rwnd, asoc->unack_data);
+
+		list_for_each_entry(sp, &asoc->peer.transport_addr_list,
+					transports) {
+			if (sp == asoc->peer.primary_path)
+				printl("*");
+
+			printl("%pISc %2u %8u %8u %8u %8u %8u ",
+			       &sp->ipaddr, sp->state, sp->cwnd, sp->ssthresh,
+			       sp->flight_size, sp->partial_bytes_acked,
+			       sp->pathmtu);
+		}
+		printl("\n");
+	}
+
+	jprobe_return();
+	return 0;
+}
+
+static struct jprobe sctp_recv_probe = {
+	.kp	= {
+		.symbol_name = "sctp_sf_eat_sack_6_2",
+	},
+	.entry	= jsctp_sf_eat_sack,
+};
+
+static __init int sctp_setup_jprobe(void)
+{
+	int ret = register_jprobe(&sctp_recv_probe);
+
+	if (ret) {
+		if (request_module("sctp"))
+			goto out;
+		ret = register_jprobe(&sctp_recv_probe);
+	}
+
+out:
+	return ret;
+}
+
+static __init int sctpprobe_init(void)
+{
+	int ret = -ENOMEM;
+
+	/* Warning: if the function signature of sctp_sf_eat_sack_6_2,
+	 * has been changed, you also have to change the signature of
+	 * jsctp_sf_eat_sack, otherwise you end up right here!
+	 */
+	BUILD_BUG_ON(__same_type(sctp_sf_eat_sack_6_2,
+				 jsctp_sf_eat_sack) == 0);
+
+	init_waitqueue_head(&sctpw.wait);
+	spin_lock_init(&sctpw.lock);
+	if (kfifo_alloc(&sctpw.fifo, bufsize, GFP_KERNEL))
+		return ret;
+
+	if (!proc_create(procname, S_IRUSR, init_net.proc_net,
+			 &sctpprobe_fops))
+		goto free_kfifo;
+
+	ret = sctp_setup_jprobe();
+	if (ret)
+		goto remove_proc;
+
+	pr_info("probe registered (port=%d/fwmark=%u) bufsize=%u\n",
+		port, fwmark, bufsize);
+	return 0;
+
+remove_proc:
+	remove_proc_entry(procname, init_net.proc_net);
+free_kfifo:
+	kfifo_free(&sctpw.fifo);
+	return ret;
+}
+
+static __exit void sctpprobe_exit(void)
+{
+	kfifo_free(&sctpw.fifo);
+	remove_proc_entry(procname, init_net.proc_net);
+	unregister_jprobe(&sctp_recv_probe);
+}
+
+module_init(sctpprobe_init);
+module_exit(sctpprobe_exit);