Transfer softnet.sh file to this repository

[zersh01]

Hi! I did a PR for softnet.sh in

https://raw.githubusercontent.com/majek/dump/master/how-to-receive-a-packet/softnet.sh

The changes take into account whether the script is running in an LXC container, and if so, it displays values only for the CPU allocated to it.

Unfortunately, the PR is still not accepted. maybe transfer the file to this repository?

[leandromoreira]

Hi @zersh01 alright, post the file here so we can discuss. Ty

[zersh01]

cat softnet.sh

#!/bin/bash

cmd="${0##*/}"

usage() {
cat >&2 <<EOI
usage: $cmd [ -h ]

Output column definitions:
      cpu  # of the cpu 

    total  # of packets (not including netpoll) received by the interrupt handler
             There might be some double counting going on:
                net/core/dev.c:1643: __get_cpu_var(netdev_rx_stat).total++;
                net/core/dev.c:1836: __get_cpu_var(netdev_rx_stat).total++;
             I think the intention was that these were originally on separate
             receive paths ... 

  dropped  # of packets that were dropped because netdev_max_backlog was exceeded

 squeezed  # of times ksoftirq ran out of netdev_budget or time slice with work
             remaining

collision  # of times that two cpus collided trying to get the device queue lock.

EOI
    exit 1
}

if [ "$1" = "-h" ]; then
    usage
fi

softnet_stats_header() {
    printf "%3s %10s %10s %10s %10s %10s %10s\n" cpu total dropped squeezed collision rps flow_limit
}

softnet_stats_format() {
    local cpu=$1
    local total_hex=$2
    local dropped_hex=$3
    local squeezed_hex=$4
    local collision_hex=$5
    local rps_hex=$6
    local flow_limit_hex=${7:-0}

    local total_dec=$((16#$total_hex))
    local dropped_dec=$((16#$dropped_hex))
    local squeezed_dec=$((16#$squeezed_hex))
    local collision_dec=$((16#$collision_hex))
    local rps_dec=$((16#$rps_hex))
    local flow_limit_dec=$((16#$flow_limit_hex))
    
    printf "%3u %10lu %10lu %10lu %10lu %10lu %10lu\n" "$cpu" "$total_dec" "$dropped_dec" "$squeezed_dec" "$collision_dec" "$rps_dec" "$flow_limit_dec"
}

is_lxc_container() {
    if systemd-detect-virt -c | grep -qi "lxc"; then
        return 0
    fi
    return 1
}

parse_cpu_ranges() {
    local IFS=','
    local range cpu_ranges=$1
    local cpus=()

    for range in $cpu_ranges; do
        if [[ $range =~ - ]]; then
            IFS='-' read start end <<< "$range"
            for ((i=start; i<=end; i++)); do
                cpus+=($i)
            done
        else
            cpus+=($range)
        fi
    done
  echo "${cpus[@]}"
}

get_lxc_cpus() {
    local cpus
    if [ -f "/sys/fs/cgroup/cpuset/lxc/cpuset.cpus" ]; then
        cpus=$(cat "/sys/fs/cgroup/cpuset/lxc/cpuset.cpus")
    elif [ -f "/sys/fs/cgroup/cpuset/cpuset.cpus" ]; then
        cpus=$(cat "/sys/fs/cgroup/cpuset/cpuset.cpus")
    else
        echo "Unable to determine allocated CPUs for LXC"
        exit 1
    fi
    parse_cpu_ranges "$cpus"
}

process_softnet_line() {
    local line=$1
    local cpu_index=$2

    set -- $line
    local total=$1
    local dropped=$2
    local squeezed=$3
    local j1=$4
    local j2=$5
    local j3=$6
    local j4=$7
    local j5=$8
    local collision=$9
    local rps=${10}
    local flow_limit_count=${11:-0}


    softnet_stats_format "$cpu_index" "$total" "$dropped" "$squeezed" "$collision" "$rps" "$flow_limit_count"
}

cpu=0
# for normal header
if is_lxc_container; then
    echo "Running inside LXC container."
    cpus=($(get_lxc_cpus))  # Получаем массив CPU
    echo "CPUs allocated to this container: ${cpus[@]}"
fi
softnet_stats_header

if is_lxc_container; then
    cpus=($(get_lxc_cpus))  # Получаем массив CPU
    while read line
    do
        if [[ " ${cpus[*]} " =~ " $cpu " ]]; then
            process_softnet_line "$line" "$cpu"
        fi
        ((cpu++))
    done < /proc/net/softnet_stat
else
#    echo "Not running inside LXC container."
    while read line
    do
        process_softnet_line "$line" "$cpu"
        ((cpu++))
    done < /proc/net/softnet_stat
fi```