net: tcp_probe: also include rcv_wnd next to snd_wnd

It is helpful to sometimes know the TCP window sizes of an established
socket e.g. to confirm that window scaling is working or to tweak the
window size to improve high-latency connections, etc etc. Currently the
TCP snooper only exports the send window size, but not the receive window
size. Therefore, also add the receive window size to the end of the
output line.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_probe.c b/net/ipv4/tcp_probe.c
index d4943f6..fae788b 100644 (file)
--- a/net/ipv4/tcp_probe.c
+++ b/net/ipv4/tcp_probe.c
@@ -60,6 +60,7 @@ struct tcp_log {
        u32     snd_nxt;
        u32     snd_una;
        u32     snd_wnd;
+       u32     rcv_wnd;
        u32     snd_cwnd;
        u32     ssthresh;
        u32     srtt;
@@ -116,6 +117,7 @@ static int jtcp_rcv_established(struct sock *sk, struct sk_buff *skb,
                        p->snd_una = tp->snd_una;
                        p->snd_cwnd = tp->snd_cwnd;
                        p->snd_wnd = tp->snd_wnd;
+                       p->rcv_wnd = tp->rcv_wnd;
                        p->ssthresh = tcp_current_ssthresh(sk);
                        p->srtt = tp->srtt >> 3;
 
@@ -157,13 +159,13 @@ static int tcpprobe_sprint(char *tbuf, int n)
                = ktime_to_timespec(ktime_sub(p->tstamp, tcp_probe.start));
 
        return scnprintf(tbuf, n,
-                       "%lu.%09lu %pI4:%u %pI4:%u %d %#x %#x %u %u %u %u\n",
+                       "%lu.%09lu %pI4:%u %pI4:%u %d %#x %#x %u %u %u %u %u\n",
                        (unsigned long) tv.tv_sec,
                        (unsigned long) tv.tv_nsec,
                        &p->saddr, ntohs(p->sport),
                        &p->daddr, ntohs(p->dport),
                        p->length, p->snd_nxt, p->snd_una,
-                       p->snd_cwnd, p->ssthresh, p->snd_wnd, p->srtt);
+                       p->snd_cwnd, p->ssthresh, p->snd_wnd, p->srtt, p->rcv_wnd);
 }
 
 static ssize_t tcpprobe_read(struct file *file, char __user *buf,