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authorWei Yongjun <yjwei@cn.fujitsu.com>2010-04-30 22:41:09 -0400
committerVlad Yasevich <vladislav.yasevich@hp.com>2010-04-30 22:41:09 -0400
commit787a51a0878f7bee3a9a83040077301e1556b69a (patch)
tree0099ddf04a475fb0c3d102a042de186351315061 /net/sctp/probe.c
parentec7b9519509061bbc09a43284c3570aa492e07f0 (diff)
sctp: implement sctp association probing module
This patch implement sctp association probing module, the module will be called sctp_probe. This module allows for capturing the changes to SCTP association state in response to incoming packets. It is used for debugging SCTP congestion control algorithms. Usage: $ modprobe sctp_probe [full=n] [port=n] [bufsize=n] $ cat /proc/net/sctpprobe The output format is: TIME ASSOC LPORT RPORT MTU RWND UNACK <REMOTE-ADDR STATE CWND SSTHRESH INFLIGHT PARTIAL_BYTES_ACKED MTU> ... The output will be like this: 9.226086 c4064c48 9000 8000 1500 53352 1 *192.168.0.19 1 4380 54784 1252 0 1500 9.287195 c4064c48 9000 8000 1500 45144 5 *192.168.0.19 1 5880 54784 6500 0 1500 9.289130 c4064c48 9000 8000 1500 42724 5 *192.168.0.19 1 7380 54784 6500 0 1500 9.620332 c4064c48 9000 8000 1500 48284 4 *192.168.0.19 1 8880 54784 5200 0 1500 ...... Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com> Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Diffstat (limited to 'net/sctp/probe.c')
-rw-r--r--net/sctp/probe.c213
1 files changed, 213 insertions, 0 deletions
diff --git a/net/sctp/probe.c b/net/sctp/probe.c
new file mode 100644
index 00000000000..8f025d5831a
--- /dev/null
+++ b/net/sctp/probe.c
@@ -0,0 +1,213 @@
+/*
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/kprobes.h>
+#include <linux/socket.h>
+#include <linux/sctp.h>
+#include <linux/proc_fs.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_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 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 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,
+};
+
+sctp_disposition_t jsctp_sf_eat_sack(const struct sctp_endpoint *ep,
+ const struct sctp_association *asoc,
+ const sctp_subtype_t type,
+ void *arg,
+ sctp_cmd_seq_t *commands)
+{
+ struct sctp_transport *sp;
+ static __u32 lcwnd = 0;
+ struct timespec now;
+
+ sp = asoc->peer.primary_path;
+
+ if ((full || sp->cwnd != lcwnd) &&
+ (!port || asoc->peer.port == port ||
+ ep->base.bind_addr.port == port)) {
+ 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("*");
+
+ if (sp->ipaddr.sa.sa_family == AF_INET)
+ printl("%pI4 ", &sp->ipaddr.v4.sin_addr);
+ else
+ printl("%pI6 ", &sp->ipaddr.v6.sin6_addr);
+
+ printl("%2u %8u %8u %8u %8u %8u ",
+ 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 sctpprobe_init(void)
+{
+ int ret = -ENOMEM;
+
+ init_waitqueue_head(&sctpw.wait);
+ spin_lock_init(&sctpw.lock);
+ if (kfifo_alloc(&sctpw.fifo, bufsize, GFP_KERNEL))
+ return ret;
+
+ if (!proc_net_fops_create(&init_net, procname, S_IRUSR,
+ &sctpprobe_fops))
+ goto free_kfifo;
+
+ ret = register_jprobe(&sctp_recv_probe);
+ if (ret)
+ goto remove_proc;
+
+ pr_info("SCTP probe registered (port=%d)\n", port);
+
+ return 0;
+
+remove_proc:
+ proc_net_remove(&init_net, procname);
+free_kfifo:
+ kfifo_free(&sctpw.fifo);
+ return ret;
+}
+
+static __exit void sctpprobe_exit(void)
+{
+ kfifo_free(&sctpw.fifo);
+ proc_net_remove(&init_net, procname);
+ unregister_jprobe(&sctp_recv_probe);
+}
+
+module_init(sctpprobe_init);
+module_exit(sctpprobe_exit);