#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
#
# Tests sysctl options {arp,ndisc}_evict_nocarrier={0,1}
#
# Create a veth pair and set IPs/routes on both. Then ping to establish
# an entry in the ARP/ND table. Depending on the test set sysctl option to
# 1 or 0. Set remote veth down which will cause local veth to go into a no
# carrier state. Depending on the test check the ARP/ND table:
#
# {arp,ndisc}_evict_nocarrier=1 should contain no ARP/ND after no carrier
# {arp,ndisc}_evict_nocarrer=0 should still contain the single ARP/ND entry
#

readonly PEER_NS="ns-peer-$(mktemp -u XXXXXX)"
readonly V4_ADDR0=10.0.10.1
readonly V4_ADDR1=10.0.10.2
readonly V6_ADDR0=2001:db8:91::1
readonly V6_ADDR1=2001:db8:91::2
nsid=100

cleanup_v6()
{
    ip netns del me
    ip netns del peer

    sysctl -w net.ipv4.conf.veth0.ndisc_evict_nocarrier=1 >/dev/null 2>&1
    sysctl -w net.ipv4.conf.all.ndisc_evict_nocarrier=1 >/dev/null 2>&1
}

create_ns()
{
    local n=${1}

    ip netns del ${n} 2>/dev/null

    ip netns add ${n}
    ip netns set ${n} $((nsid++))
    ip -netns ${n} link set lo up
}


setup_v6() {
    create_ns me
    create_ns peer

    IP="ip -netns me"

    $IP li add veth1 type veth peer name veth2
    $IP li set veth1 up
    $IP -6 addr add $V6_ADDR0/64 dev veth1 nodad
    $IP li set veth2 netns peer up
    ip -netns peer -6 addr add $V6_ADDR1/64 dev veth2 nodad

    ip netns exec me sysctl -w $1 >/dev/null 2>&1

    # Establish an ND cache entry
    ip netns exec me ping -6 -c1 -Iveth1 $V6_ADDR1 >/dev/null 2>&1
    # Should have the veth1 entry in ND table
    ip netns exec me ip -6 neigh get $V6_ADDR1 dev veth1 >/dev/null 2>&1
    if [ $? -ne 0 ]; then
        cleanup_v6
        echo "failed"
        exit
    fi

    # Set veth2 down, which will put veth1 in NOCARRIER state
    ip netns exec peer ip link set veth2 down
}

setup_v4() {
    ip netns add "${PEER_NS}"
    ip link add name veth0 type veth peer name veth1
    ip link set dev veth0 up
    ip link set dev veth1 netns "${PEER_NS}"
    ip netns exec "${PEER_NS}" ip link set dev veth1 up
    ip addr add $V4_ADDR0/24 dev veth0
    ip netns exec "${PEER_NS}" ip addr add $V4_ADDR1/24 dev veth1
    ip netns exec ${PEER_NS} ip route add default via $V4_ADDR1 dev veth1
    ip route add default via $V4_ADDR0 dev veth0

    sysctl -w "$1" >/dev/null 2>&1

    # Establish an ARP cache entry
    ping -c1 -I veth0 $V4_ADDR1 -q >/dev/null 2>&1
    # Should have the veth1 entry in ARP table
    ip neigh get $V4_ADDR1 dev veth0 >/dev/null 2>&1
    if [ $? -ne 0 ]; then
        cleanup_v4
        echo "failed"
        exit
    fi

    # Set veth1 down, which will put veth0 in NOCARRIER state
    ip netns exec "${PEER_NS}" ip link set veth1 down
}

cleanup_v4() {
    ip neigh flush dev veth0
    ip link del veth0
    local -r ns="$(ip netns list|grep $PEER_NS)"
    [ -n "$ns" ] && ip netns del $ns 2>/dev/null

    sysctl -w net.ipv4.conf.veth0.arp_evict_nocarrier=1 >/dev/null 2>&1
    sysctl -w net.ipv4.conf.all.arp_evict_nocarrier=1 >/dev/null 2>&1
}

# Run test when arp_evict_nocarrier = 1 (default).
run_arp_evict_nocarrier_enabled() {
    echo "run arp_evict_nocarrier=1 test"
    setup_v4 "net.ipv4.conf.veth0.arp_evict_nocarrier=1"

    # ARP table should be empty
    ip neigh get $V4_ADDR1 dev veth0 >/dev/null 2>&1

    if [ $? -eq 0 ];then
        echo "failed"
    else
        echo "ok"
    fi

    cleanup_v4
}

# Run test when arp_evict_nocarrier = 0
run_arp_evict_nocarrier_disabled() {
    echo "run arp_evict_nocarrier=0 test"
    setup_v4 "net.ipv4.conf.veth0.arp_evict_nocarrier=0"

    # ARP table should still contain the entry
    ip neigh get $V4_ADDR1 dev veth0 >/dev/null 2>&1

    if [ $? -eq 0 ];then
        echo "ok"
    else
        echo "failed"
    fi

    cleanup_v4
}

run_arp_evict_nocarrier_disabled_all() {
    echo "run all.arp_evict_nocarrier=0 test"
    setup_v4 "net.ipv4.conf.all.arp_evict_nocarrier=0"

    # ARP table should still contain the entry
    ip neigh get $V4_ADDR1 dev veth0 >/dev/null 2>&1

    if [ $? -eq 0 ];then
        echo "ok"
    else
        echo "failed"
    fi

    cleanup_v4
}

run_ndisc_evict_nocarrier_enabled() {
    echo "run ndisc_evict_nocarrier=1 test"

    setup_v6 "net.ipv6.conf.veth1.ndisc_evict_nocarrier=1"

    ip netns exec me ip -6 neigh get $V6_ADDR1 dev veth1 >/dev/null 2>&1

    if [ $? -eq 0 ];then
        echo "failed"
    else
        echo "ok"
    fi

    cleanup_v6
}

run_ndisc_evict_nocarrier_disabled() {
    echo "run ndisc_evict_nocarrier=0 test"

    setup_v6 "net.ipv6.conf.veth1.ndisc_evict_nocarrier=0"

    ip netns exec me ip -6 neigh get $V6_ADDR1 dev veth1 >/dev/null 2>&1

    if [ $? -eq 0 ];then
        echo "ok"
    else
        echo "failed"
    fi

    cleanup_v6
}

run_ndisc_evict_nocarrier_disabled_all() {
    echo "run all.ndisc_evict_nocarrier=0 test"

    setup_v6 "net.ipv6.conf.all.ndisc_evict_nocarrier=0"

    ip netns exec me ip -6 neigh get $V6_ADDR1 dev veth1 >/dev/null 2>&1

    if [ $? -eq 0 ];then
        echo "ok"
    else
        echo "failed"
    fi

    cleanup_v6
}

run_all_tests() {
    run_arp_evict_nocarrier_enabled
    run_arp_evict_nocarrier_disabled
    run_arp_evict_nocarrier_disabled_all
    run_ndisc_evict_nocarrier_enabled
    run_ndisc_evict_nocarrier_disabled
    run_ndisc_evict_nocarrier_disabled_all
}

if [ "$(id -u)" -ne 0 ];then
	echo "SKIP: Need root privileges"
	exit $ksft_skip;
fi

run_all_tests