#! /bin/bash
# SPDX-License-Identifier: GPL-2.0

readonly KSFT_FAIL=1
readonly KSFT_SKIP=4

# SELFTESTS_MPTCP_LIB_EXPECT_ALL_FEATURES env var can be set when validating all
# features using the last version of the kernel and the selftests to make sure
# a test is not being skipped by mistake.
mptcp_lib_expect_all_features() {
	[ "${SELFTESTS_MPTCP_LIB_EXPECT_ALL_FEATURES:-}" = "1" ]
}

# $1: msg
mptcp_lib_fail_if_expected_feature() {
	if mptcp_lib_expect_all_features; then
		echo "ERROR: missing feature: ${*}"
		exit ${KSFT_FAIL}
	fi

	return 1
}

# $1: file
mptcp_lib_has_file() {
	local f="${1}"

	if [ -f "${f}" ]; then
		return 0
	fi

	mptcp_lib_fail_if_expected_feature "${f} file not found"
}

mptcp_lib_check_mptcp() {
	if ! mptcp_lib_has_file "/proc/sys/net/mptcp/enabled"; then
		echo "SKIP: MPTCP support is not available"
		exit ${KSFT_SKIP}
	fi
}

mptcp_lib_check_kallsyms() {
	if ! mptcp_lib_has_file "/proc/kallsyms"; then
		echo "SKIP: CONFIG_KALLSYMS is missing"
		exit ${KSFT_SKIP}
	fi
}

# Internal: use mptcp_lib_kallsyms_has() instead
__mptcp_lib_kallsyms_has() {
	local sym="${1}"

	mptcp_lib_check_kallsyms

	grep -q " ${sym}" /proc/kallsyms
}

# $1: part of a symbol to look at, add '$' at the end for full name
mptcp_lib_kallsyms_has() {
	local sym="${1}"

	if __mptcp_lib_kallsyms_has "${sym}"; then
		return 0
	fi

	mptcp_lib_fail_if_expected_feature "${sym} symbol not found"
}

# $1: part of a symbol to look at, add '$' at the end for full name
mptcp_lib_kallsyms_doesnt_have() {
	local sym="${1}"

	if ! __mptcp_lib_kallsyms_has "${sym}"; then
		return 0
	fi

	mptcp_lib_fail_if_expected_feature "${sym} symbol has been found"
}

# !!!AVOID USING THIS!!!
# Features might not land in the expected version and features can be backported
#
# $1: kernel version, e.g. 6.3
mptcp_lib_kversion_ge() {
	local exp_maj="${1%.*}"
	local exp_min="${1#*.}"
	local v maj min

	# If the kernel has backported features, set this env var to 1:
	if [ "${SELFTESTS_MPTCP_LIB_NO_KVERSION_CHECK:-}" = "1" ]; then
		return 0
	fi

	v=$(uname -r | cut -d'.' -f1,2)
	maj=${v%.*}
	min=${v#*.}

	if   [ "${maj}" -gt "${exp_maj}" ] ||
	   { [ "${maj}" -eq "${exp_maj}" ] && [ "${min}" -ge "${exp_min}" ]; }; then
		return 0
	fi

	mptcp_lib_fail_if_expected_feature "kernel version ${1} lower than ${v}"
}