How to get real-time network statistics in Linux with KB/MB/Bytes format and for specific port or application processID?

Question

I used IPTraf, Iftop, vnstat, bwm-ng, ifconfig -a. None of them is helping me to find real-time packets that are being sent/received from my application in KB or MB format. The reason is I am writing an application, where I need to be very sure my compression is correct, but I can't test to move forward.

What I can use to track very specific and accurate real-time network statistics?

Answer 1

Your application is probably sending packets to a specific UDP or TCP port number or to a specific IP-address.

You can therefore use something like TCPdump to capture that traffic.

TCPdump doesn't give you the real-time stats you desire but you can feed it's output to something that does (I'll try to update this answer with an answer later).

---

Update:

$ sudo tcpdump -i eth1 -l -e -n | ./netbps
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth1, link-type EN10MB (Ethernet), capture size 96 bytes
11:36:53    2143.33 Bps
11:37:03    1995.99 Bps
11:37:13    2008.35 Bps
11:37:23    1999.97 Bps
11:37:33    2083.32 Bps
131 packets captured
131 packets received by filter
0 packets dropped by kernel

I interrupted that after a minute by pressing Ctrl+C.

You'd need to add a suitable filter expression at the end of the tcpdump command to only include the traffic generated by your app (e.g. port 123)

The program netbps is this:

#!/usr/bin/perl
use strict;
use warnings;
use Time::HiRes;

my $reporting_interval = 10.0; # seconds
my $bytes_this_interval = 0;
my $start_time = [Time::HiRes::gettimeofday()];

STDOUT->autoflush(1);

while (<>) {
  if (/ length (\d+):/) {
    $bytes_this_interval += $1;
    my $elapsed_seconds = Time::HiRes::tv_interval($start_time);
    if ($elapsed_seconds > $reporting_interval) {
       my $bps = $bytes_this_interval / $elapsed_seconds;
       printf "%02d:%02d:%02d %10.2f Bps\n", (localtime())[2,1,0],$bps;
       $start_time = [Time::HiRes::gettimeofday()];
       $bytes_this_interval = 0;
    }
  }
}

It's just an example, adjust to taste.

Answer 2

Usage as below from same folder:

To check packer per interface: ./netpps.sh eth0

To check speed per interface: ./netspeed.sh eth0

Measure Packets per Second on an Interface netpps.sh as file name

#!/bin/bash

INTERVAL="1"  # update interval in seconds

if [ -z "$1" ]; then
        echo
        echo usage: $0 [network-interface]
        echo
        echo e.g. $0 eth0
        echo
        echo shows packets-per-second
        exit
fi

IF=$1

while true
do
        R1=`cat /sys/class/net/$1/statistics/rx_packets`
        T1=`cat /sys/class/net/$1/statistics/tx_packets`
        sleep $INTERVAL
        R2=`cat /sys/class/net/$1/statistics/rx_packets`
        T2=`cat /sys/class/net/$1/statistics/tx_packets`
        TXPPS=`expr $T2 - $T1`
        RXPPS=`expr $R2 - $R1`
        echo "TX $1: $TXPPS pkts/s RX $1: $RXPPS pkts/s"
done

Measure Network Bandwidth on an Interface netspeed.sh as file name

#!/bin/bash

INTERVAL="1"  # update interval in seconds

if [ -z "$1" ]; then
        echo
        echo usage: $0 [network-interface]
        echo
        echo e.g. $0 eth0
        echo
        exit
fi

IF=$1

while true
do
        R1=`cat /sys/class/net/$1/statistics/rx_bytes`
        T1=`cat /sys/class/net/$1/statistics/tx_bytes`
        sleep $INTERVAL
        R2=`cat /sys/class/net/$1/statistics/rx_bytes`
        T2=`cat /sys/class/net/$1/statistics/tx_bytes`
        TBPS=`expr $T2 - $T1`
        RBPS=`expr $R2 - $R1`
        TKBPS=`expr $TBPS / 1024`
        RKBPS=`expr $RBPS / 1024`
        echo "TX $1: $TKBPS kB/s RX $1: $RKBPS kB/s"
done

Please refer this site for more info http://xmodulo.com/measure-packets-per-second-throughput-high-speed-network-interface.html

Answer 3

Easiest to use and easiest to control output and redirect to file for continuous logging:

ifstat

Probably comes with most linux distributions, and can be installed with brew on mac

Answer 4

I think you can use the proc interface to get the information you need. I created this little shell script called rt_traf.sh:

#!/bin/bash

cat /proc/$1/net/netstat | grep 'IpExt: ' | tail -n 1 | awk '{ print $8 "\t" $9 }'

This will print the in and out octets separated by a tab. Octets multiplied by 8 will give you bits/second and then divided by 10^6 will give you megabits/second. Of course you can add this to the shell script to format the output how you want it. You can call this with the PID of your application like so ./rt_traf.sh <PID> which will give you an instantaneous reading of your application since startup. To watch real time stats per second you can wrap the shell script in the watch command:

watch -n 1 ./rt_traf.sh <PID>

The -n parameter can be adjusted all the way down to tenths of a second. To do a calculation over time I would do something like this:

PID=<PID>; START=`./rt_traf.sh $PID`;IN_START=`echo $START | awk '{ print $1 }'`; OUT_START=`echo $START | awk '{ print $2 }'`; sleep 10; END=`./rt_traf.sh $PID`; IN_END=`echo $END | awk '{ print $1 }'`; OUT_END=`echo $END | awk '{ print $2 }'`; IN_BPS=`echo "scale=2; (($IN_START-$IN_END)/10)/8" | bc`; OUT_BPS=`echo "scale=2; (($OUT_START-$OUT_END)/10)/8" | bc`; echo "In: " $IN_BPS "Bits/second"; echo "Out: " $OUT_BPS "Bits/second"

Again the math can be adjusted for the size/times you need. Not the most elegant or shrink wrapped solution but it should work in a pinch.

Answer 5

I just needed to measure how much mysql traffic is going in and out on an old system where perl didn't work properly, so I couldn't resist writing few lines of awk that serve the same goal of measuring total traffic seen by tcpdump:

# tcpdump -l -e -n port 3306 | \
  awk '{
  t=substr($1, 0, 8);
  n=substr($9, 0, length($9)-1);
  if(t != pt){
    print t, sum;
    sum = 0;
  } else {
    sum += n
  }
  pt=t;
}'

tcpdump: WARNING: eth0: no IPv4 address assigned
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
14:41:54 
14:41:55 466905
14:41:56 765220
14:41:57 741511
14:41:58 688219
14:41:59 492322
14:42:00 800087
14:42:01 1248608
14:42:02 1276476
14:42:03 755586
14:42:04 1029453
14:42:05 818298
^C32515 packets captured
32633 packets received by filter
107 packets dropped by kernel

And if you like one-liners better, here's one for you:

tcpdump -l -e -n port 3306 | awk '{t=substr($1,0,8);n=substr($9,0,length($9)-1);if(t!=pt){print t,sum;sum=0;}else{sum+=n}pt=t;}'

Answer 6

Per application can be done with a firewall rule using xtables and a modification of the below.

This doesn't answer the "per application" question but just the "per interface" one.

Below is a script that works on most embedded Linux routers such as Ubiquiti and OpenWRT compatible ones and gets its details from /proc/net/dev.

(And easy to change to packets etc.)

#!/bin/sh

SLP=1 # output / sleep interval
DEVICE=$1
IS_GOOD=0
for GOOD_DEVICE in `grep \: /proc/net/dev | awk -F: '{print $1}'`; do
    if [ "$DEVICE" = $GOOD_DEVICE ]; then
        IS_GOOD=1
        break
    fi
done

if [ $IS_GOOD -eq 0 ]; then
    echo "Device not found. Should be one of these:"
        grep ":" /proc/net/dev | awk -F: '{print $1}' | sed s@\ @@g 
    exit 1
fi

while true; do

LINE=`grep $1 /proc/net/dev | sed s/.*://`;
RECEIVED1=`echo $LINE | awk '{print $1}'`
TRANSMITTED1=`echo $LINE | awk '{print $9}'`
TOTAL=$(($RECEIVED1+$TRANSMITTED1))

sleep $SLP

LINE=`grep $1 /proc/net/dev | sed s/.*://`;
RECEIVED2=`echo $LINE | awk '{print $1}'`
TRANSMITTED2=`echo $LINE | awk '{print $9}'`
SPEED=$((($RECEIVED2+$TRANSMITTED2-$TOTAL)/$SLP))
INSPEED=$((($RECEIVED2-$RECEIVED1)/$SLP))
OUTSPEED=$((($TRANSMITTED2-$TRANSMITTED1)/$SLP))

printf "In: %12i KB/s | Out: %12i KB/s | Total: %12i KB/s\n" $(($INSPEED/1024)) $(($OUTSPEED/1024)) $((($INSPEED+$OUTSPEED)/1024)) ;

done;

Copy the above to your clipboard and then in a terminal session on your router:

$ cat > /tmp/n.sh

then: Ctrl+V (or right click / Paste)

then: Ctrl+D

$ chmod +x /tmp/n.sh

$ /tmp/n.sh eth0

You can also paste it in a notepad, then just repeat the above if you need to edit it - not all embedded routers have an editor! Make sure you copy everything from the # at the top to the done; at the bottom.

The netpps example above is great BTW - but not all devices have a mounted /sys filesystem. You might also have to change the /bin/bash to /bin/sh or vice versa.

Source: https://gist.github.com/dagelf/ab2bad26ce96fa8d79b0834cd8cab549