mptcp-get-debug

#! /bin/sh
# SPDX-License-Identifier: BSD-3-Clause
#
# Copyright (c) 2024, Matthieu Baerts

SCRIPT="$(basename "${0}")"
VERSION="1"
PID_IP=

EQ="========================================"

title() {
    printf "\n%s\n%s\n%s\n" "${EQ}" "${*}" "${EQ}"
}

stdout() {
    printf "\n%s\n" "${*}"
}

stderr() {
    stdout "${@}" >&2
}

cmd() {
    title "${*}"
    "${@}" 2>&1
}

start_ip_mptcp_monitor() {
    title "ip mptcp monitor: start"
    ip mptcp monitor 2>&1 &  # not using cmd to get the right PID
    PID_IP=$!

    sleep 0.1 2>/dev/null || sleep 1

    for _ in $(seq 20); do
        out="$(ss -f netlink -H "src = rtnl:${PID_IP}" 2>/dev/null)" || break
        [ "$(echo "${out}" | wc -l)" != 0 ] && return 0

        sleep 0.1 2>/dev/null || break
    done

    if [ ! -d "/proc/${PID_IP}" ]; then
        stdout "ip monitor has been killed"
        return 1
    fi
}

stop_ip_mptcp_monitor() {
    title "ip mptcp monitor: stop"

    if [ -n "${PID_IP}" ] && [ -d "/proc/${PID_IP}" ]; then
        kill "${PID_IP}"
    fi
}

collect_data_pre() {
    stdout "${SCRIPT}: version ${VERSION}"

    if [ "$(id -u)" != 0 ]; then
        stderr "This script is not executed as root, not all info can be collected."
        stderr "Press Enter to continue, Ctrl+C to stop"
        read -r _
    fi

    cmd uname -a
    cmd cat /etc/os-release
    cmd sysctl net.mptcp
    cmd ip mptcp endpoint show
    cmd ip mptcp limits show
}

collect_data_post() {
    cmd ss -ManiH
    cmd nstat
}

collect_data() {
    collect_data_pre
    collect_data_post
}

collect_data_repro() {
    collect_data_pre

    cmd ss -ManiH
    nstat -n 2>&1
    start_ip_mptcp_monitor

    stderr "Please reproduce the issue now, then press the Enter key when it is done."
    read -r _

    collect_data_post
    stop_ip_mptcp_monitor
}

version() {
    printf "%s: version %s\n" "${SCRIPT}" ${VERSION}
}

usage() {
    version
    printf "\n"
    printf "  -c | --collect      Collect info and exit.\n"
    printf "  -r | --reproduce    Collect info, start monitor, wait for user and exit.\n"
    printf "  -h | --help         Show this and exit.\n"
    printf "  -v | --version      Show the version and exit.\n"
    printf "\n"
    printf "Please check https://mptcp.dev website for more info.\n"
}

case "${1}" in
    "-c" | "--collect")
        collect_data
        ;;
    "-r" | "--reproduce")
        collect_data_repro
        ;;
    "-h" | "--help")
        usage
        ;;
    "-v" | "--version")
        version
        ;;
    *)
        usage >&2
        exit 1
        ;;
esac

exit 0