[TCP] tcp_probe: improvements for net-2.6.22

Change tcp_probe to use ktime (needed to add one export).
Add option to only get events when cwnd changes - from Doug Leith

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 39 insertions, 29 deletions

diff --git a/net/ipv4/tcp_probe.c b/net/ipv4/tcp_probe.c
index 61f406f27294..3938d5dbdf20 100644
--- a/net/ipv4/tcp_probe.c
+++ b/net/ipv4/tcp_probe.c
@@ -26,6 +26,8 @@
 #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>
@@ -34,43 +36,45 @@ MODULE_AUTHOR("Stephen Hemminger <shemminger@linux-foundation.org>");
 MODULE_DESCRIPTION("TCP cwnd snooper");
 MODULE_LICENSE("GPL");
 
-static int port = 0;
+static int port __read_mostly = 0;
 MODULE_PARM_DESC(port, "Port to match (0=all)");
 module_param(port, int, 0);
 
-static int bufsize = 64*1024;
+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;
+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 {
-        struct kfifo  *fifo;
-        spinlock_t    lock;
+        struct kfifo    *fifo;
+        spinlock_t      lock;
         wait_queue_head_t wait;
-        struct timeval tstart;
+        ktime_t         start;
+        u32             lastcwnd;
 } tcpw;
 
+/*
+ * Print to log with timestamps.
+ * FIXME: causes an extra copy
+ */
 static void printl(const char *fmt, ...)
 {
         va_list args;
         int len;
-        struct timeval now;
+        struct timespec tv;
         char tbuf[256];
 
         va_start(args, fmt);
-        do_gettimeofday(&now);
+        /* want monotonic time since start of tcp_probe */
+        tv = ktime_to_timespec(ktime_sub(ktime_get(), tcpw.start));
 
-        now.tv_sec -= tcpw.tstart.tv_sec;
-        now.tv_usec -= tcpw.tstart.tv_usec;
-        if (now.tv_usec < 0) {
-                --now.tv_sec;
-                now.tv_usec += 1000000;
-        }
-
-        len = sprintf(tbuf, "%lu.%06lu ",
-                      (unsigned long) now.tv_sec,
-                      (unsigned long) now.tv_usec);
+        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);
 
@@ -78,38 +82,44 @@ static void printl(const char *fmt, ...)
         wake_up(&tcpw.wait);
 }
 
-static int jtcp_sendmsg(struct kiocb *iocb, struct sock *sk,
-                        struct msghdr *msg, size_t size)
+/*
+ * 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);
 
-        if (port == 0 || ntohs(inet->dport) == port ||
-            ntohs(inet->sport) == port) {
+        /* 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\n",
                        NIPQUAD(inet->saddr), ntohs(inet->sport),
                        NIPQUAD(inet->daddr), ntohs(inet->dport),
-                       size, tp->snd_nxt, tp->snd_una,
+                       skb->len, tp->snd_nxt, tp->snd_una,
                        tp->snd_cwnd, tcp_current_ssthresh(sk),
-                       tp->snd_wnd);
+                       tp->snd_wnd, tp->srtt >> 3);
+                tcpw.lastcwnd = tp->snd_cwnd;
         }
 
         jprobe_return();
         return 0;
 }
 
-static struct jprobe tcp_send_probe = {
+static struct jprobe tcp_probe = {
         .kp = {
-                .symbol_name    = "tcp_sendmsg",
+                .symbol_name    = "tcp_rcv_established",
         },
-        .entry  = JPROBE_ENTRY(jtcp_sendmsg),
+        .entry  = JPROBE_ENTRY(jtcp_rcv_established),
 };
 
 
 static int tcpprobe_open(struct inode * inode, struct file * file)
 {
         kfifo_reset(tcpw.fifo);
-        do_gettimeofday(&tcpw.tstart);
+        tcpw.start = ktime_get();
         return 0;
 }
 
@@ -162,7 +172,7 @@ static __init int tcpprobe_init(void)
         if (!proc_net_fops_create(procname, S_IRUSR, &tcpprobe_fops))
                 goto err0;
 
-        ret = register_jprobe(&tcp_send_probe);
+        ret = register_jprobe(&tcp_probe);
         if (ret)
                 goto err1;
 
@@ -180,7 +190,7 @@ static __exit void tcpprobe_exit(void)
 {
         kfifo_free(tcpw.fifo);
         proc_net_remove(procname);
-        unregister_jprobe(&tcp_send_probe);
+        unregister_jprobe(&tcp_probe);
 
 }
 module_exit(tcpprobe_exit);