netcons_fragmented_msg.sh

  1#!/usr/bin/env bash
  2# SPDX-License-Identifier: GPL-2.0
  3
  4# Test netconsole's message fragmentation functionality.
  5#
  6# When a message exceeds the maximum packet size, netconsole splits it into
  7# multiple fragments for transmission. This test verifies:
  8#  - Correct fragmentation of large messages
  9#  - Proper reassembly of fragments at the receiver
 10#  - Preservation of userdata across fragments
 11#  - Behavior with and without kernel release version appending
 12#
 13# Author: Breno Leitao <leitao@debian.org>
 14
 15set -euo pipefail
 16
 17SCRIPTDIR=$(dirname "$(readlink -e "${BASH_SOURCE[0]}")")
 18
 19source "${SCRIPTDIR}"/lib/sh/lib_netcons.sh
 20
 21modprobe netdevsim 2> /dev/null || true
 22modprobe netconsole 2> /dev/null || true
 23
 24# The content of kmsg will be save to the following file
 25OUTPUT_FILE="/tmp/${TARGET}"
 26
 27# set userdata to a long value. In this case, it is "1-2-3-4...50-"
 28USERDATA_VALUE=$(printf -- '%.2s-' {1..60})
 29
 30# Convert the header string in a regexp, so, we can remove
 31# the second header as well.
 32# A header looks like "13,468,514729715,-,ncfrag=0/1135;". If
 33# release is appended, you might find something like:L
 34# "6.13.0-04048-g4f561a87745a,13,468,514729715,-,ncfrag=0/1135;"
 35function header_to_regex() {
 36	# header is everything before ;
 37	local HEADER="${1}"
 38	REGEX=$(echo "${HEADER}" | cut -d'=' -f1)
 39	echo "${REGEX}=[0-9]*\/[0-9]*;"
 40}
 41
 42# We have two headers in the message. Remove both to get the full message,
 43# and extract the full message.
 44function extract_msg() {
 45	local MSGFILE="${1}"
 46	# Extract the header, which is the very first thing that arrives in the
 47	# first list.
 48	HEADER=$(sed -n '1p' "${MSGFILE}" | cut -d';' -f1)
 49	HEADER_REGEX=$(header_to_regex "${HEADER}")
 50
 51	# Remove the two headers from the received message
 52	# This will return the message without any header, similarly to what
 53	# was sent.
 54	sed "s/""${HEADER_REGEX}""//g" "${MSGFILE}"
 55}
 56
 57# Validate the message, which has two messages glued together.
 58# unwrap them to make sure all the characters were transmitted.
 59# File will look like the following:
 60#  13,468,514729715,-,ncfrag=0/1135;<message>
 61#   key=<part of key>-13,468,514729715,-,ncfrag=967/1135;<rest of the key>
 62function validate_fragmented_result() {
 63	# Discard the netconsole headers, and assemble the full message
 64	RCVMSG=$(extract_msg "${1}")
 65
 66	# check for the main message
 67	if ! echo "${RCVMSG}" | grep -q "${MSG}"; then
 68		echo "Message body doesn't match." >&2
 69		echo "msg received=" "${RCVMSG}" >&2
 70		exit "${ksft_fail}"
 71	fi
 72
 73	# check userdata
 74	if ! echo "${RCVMSG}" | grep -q "${USERDATA_VALUE}"; then
 75		echo "message userdata doesn't match" >&2
 76		echo "msg received=" "${RCVMSG}" >&2
 77		exit "${ksft_fail}"
 78	fi
 79	# test passed. hooray
 80}
 81
 82# Check for basic system dependency and exit if not found
 83check_for_dependencies
 84# Set current loglevel to KERN_INFO(6), and default to KERN_NOTICE(5)
 85echo "6 5" > /proc/sys/kernel/printk
 86# Remove the namespace, interfaces and netconsole target on exit
 87trap cleanup EXIT
 88# Create one namespace and two interfaces
 89set_network
 90# Create a dynamic target for netconsole
 91create_dynamic_target
 92# Set userdata "key" with the "value" value
 93set_user_data
 94
 95
 96# TEST 1: Send message and userdata. They will fragment
 97# =======
 98MSG=$(printf -- 'MSG%.3s=' {1..150})
 99
100# Listen for netconsole port inside the namespace and destination interface
101listen_port_and_save_to "${OUTPUT_FILE}" &
102# Wait for socat to start and listen to the port.
103wait_local_port_listen "${NAMESPACE}" "${PORT}" udp
104# Send the message
105echo "${MSG}: ${TARGET}" > /dev/kmsg
106# Wait until socat saves the file to disk
107busywait "${BUSYWAIT_TIMEOUT}" test -s "${OUTPUT_FILE}"
108# Check if the message was not corrupted
109validate_fragmented_result "${OUTPUT_FILE}"
110
111# TEST 2: Test with smaller message, and without release appended
112# =======
113MSG=$(printf -- 'FOOBAR%.3s=' {1..100})
114# Let's disable release and test again.
115disable_release_append
116
117listen_port_and_save_to "${OUTPUT_FILE}" &
118wait_local_port_listen "${NAMESPACE}" "${PORT}" udp
119echo "${MSG}: ${TARGET}" > /dev/kmsg
120busywait "${BUSYWAIT_TIMEOUT}" test -s "${OUTPUT_FILE}"
121validate_fragmented_result "${OUTPUT_FILE}"
122exit "${ksft_pass}"