Commit f9a2fb73 authored by Arun Ajith S's avatar Arun Ajith S Committed by David S. Miller

net/ipv6: Introduce accept_unsolicited_na knob to implement router-side changes for RFC9131

Add a new neighbour cache entry in STALE state for routers on receiving
an unsolicited (gratuitous) neighbour advertisement with
target link-layer-address option specified.
This is similar to the arp_accept configuration for IPv4.
A new sysctl endpoint is created to turn on this behaviour:
/proc/sys/net/ipv6/conf/interface/accept_unsolicited_na.
Signed-off-by: default avatarArun Ajith S <aajith@arista.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0339d25a
......@@ -2467,6 +2467,33 @@ drop_unsolicited_na - BOOLEAN
By default this is turned off.
accept_unsolicited_na - BOOLEAN
Add a new neighbour cache entry in STALE state for routers on receiving an
unsolicited neighbour advertisement with target link-layer address option
specified. This is as per router-side behavior documented in RFC9131.
This has lower precedence than drop_unsolicited_na.
==== ====== ====== ==============================================
drop accept fwding behaviour
---- ------ ------ ----------------------------------------------
1 X X Drop NA packet and don't pass up the stack
0 0 X Pass NA packet up the stack, don't update NC
0 1 0 Pass NA packet up the stack, don't update NC
0 1 1 Pass NA packet up the stack, and add a STALE
NC entry
==== ====== ====== ==============================================
This will optimize the return path for the initial off-link communication
that is initiated by a directly connected host, by ensuring that
the first-hop router which turns on this setting doesn't have to
buffer the initial return packets to do neighbour-solicitation.
The prerequisite is that the host is configured to send
unsolicited neighbour advertisements on interface bringup.
This setting should be used in conjunction with the ndisc_notify setting
on the host to satisfy this prerequisite.
By default this is turned off.
enhanced_dad - BOOLEAN
Include a nonce option in the IPv6 neighbor solicitation messages used for
duplicate address detection per RFC7527. A received DAD NS will only signal
......
......@@ -61,6 +61,7 @@ struct ipv6_devconf {
__s32 suppress_frag_ndisc;
__s32 accept_ra_mtu;
__s32 drop_unsolicited_na;
__s32 accept_unsolicited_na;
struct ipv6_stable_secret {
bool initialized;
struct in6_addr secret;
......
......@@ -194,6 +194,7 @@ enum {
DEVCONF_IOAM6_ID,
DEVCONF_IOAM6_ID_WIDE,
DEVCONF_NDISC_EVICT_NOCARRIER,
DEVCONF_ACCEPT_UNSOLICITED_NA,
DEVCONF_MAX
};
......
......@@ -5587,6 +5587,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
array[DEVCONF_IOAM6_ID] = cnf->ioam6_id;
array[DEVCONF_IOAM6_ID_WIDE] = cnf->ioam6_id_wide;
array[DEVCONF_NDISC_EVICT_NOCARRIER] = cnf->ndisc_evict_nocarrier;
array[DEVCONF_ACCEPT_UNSOLICITED_NA] = cnf->accept_unsolicited_na;
}
static inline size_t inet6_ifla6_size(void)
......@@ -7037,6 +7038,15 @@ static const struct ctl_table addrconf_sysctl[] = {
.extra1 = (void *)SYSCTL_ZERO,
.extra2 = (void *)SYSCTL_ONE,
},
{
.procname = "accept_unsolicited_na",
.data = &ipv6_devconf.accept_unsolicited_na,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = (void *)SYSCTL_ZERO,
.extra2 = (void *)SYSCTL_ONE,
},
{
/* sentinel */
}
......
......@@ -979,6 +979,7 @@ static void ndisc_recv_na(struct sk_buff *skb)
struct inet6_dev *idev = __in6_dev_get(dev);
struct inet6_ifaddr *ifp;
struct neighbour *neigh;
bool create_neigh;
if (skb->len < sizeof(struct nd_msg)) {
ND_PRINTK(2, warn, "NA: packet too short\n");
......@@ -999,6 +1000,7 @@ static void ndisc_recv_na(struct sk_buff *skb)
/* For some 802.11 wireless deployments (and possibly other networks),
* there will be a NA proxy and unsolicitd packets are attacks
* and thus should not be accepted.
* drop_unsolicited_na takes precedence over accept_unsolicited_na
*/
if (!msg->icmph.icmp6_solicited && idev &&
idev->cnf.drop_unsolicited_na)
......@@ -1039,7 +1041,23 @@ static void ndisc_recv_na(struct sk_buff *skb)
in6_ifa_put(ifp);
return;
}
neigh = neigh_lookup(&nd_tbl, &msg->target, dev);
/* RFC 9131 updates original Neighbour Discovery RFC 4861.
* An unsolicited NA can now create a neighbour cache entry
* on routers if it has Target LL Address option.
*
* drop accept fwding behaviour
* ---- ------ ------ ----------------------------------------------
* 1 X X Drop NA packet and don't pass up the stack
* 0 0 X Pass NA packet up the stack, don't update NC
* 0 1 0 Pass NA packet up the stack, don't update NC
* 0 1 1 Pass NA packet up the stack, and add a STALE
* NC entry
* Note that we don't do a (daddr == all-routers-mcast) check.
*/
create_neigh = !msg->icmph.icmp6_solicited && lladdr &&
idev && idev->cnf.forwarding &&
idev->cnf.accept_unsolicited_na;
neigh = __neigh_lookup(&nd_tbl, &msg->target, dev, create_neigh);
if (neigh) {
u8 old_flags = neigh->flags;
......
......@@ -36,6 +36,7 @@ TEST_PROGS += srv6_end_dt4_l3vpn_test.sh
TEST_PROGS += srv6_end_dt6_l3vpn_test.sh
TEST_PROGS += vrf_strict_mode_test.sh
TEST_PROGS += arp_ndisc_evict_nocarrier.sh
TEST_PROGS += ndisc_unsolicited_na_test.sh
TEST_PROGS_EXTENDED := in_netns.sh setup_loopback.sh setup_veth.sh
TEST_PROGS_EXTENDED += toeplitz_client.sh toeplitz.sh
TEST_GEN_FILES = socket nettest
......
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
# This test is for the accept_unsolicited_na feature to
# enable RFC9131 behaviour. The following is the test-matrix.
# drop accept fwding behaviour
# ---- ------ ------ ----------------------------------------------
# 1 X X Drop NA packet and don't pass up the stack
# 0 0 X Pass NA packet up the stack, don't update NC
# 0 1 0 Pass NA packet up the stack, don't update NC
# 0 1 1 Pass NA packet up the stack, and add a STALE
# NC entry
ret=0
# Kselftest framework requirement - SKIP code is 4.
ksft_skip=4
PAUSE_ON_FAIL=no
PAUSE=no
HOST_NS="ns-host"
ROUTER_NS="ns-router"
HOST_INTF="veth-host"
ROUTER_INTF="veth-router"
ROUTER_ADDR="2000:20::1"
HOST_ADDR="2000:20::2"
SUBNET_WIDTH=64
ROUTER_ADDR_WITH_MASK="${ROUTER_ADDR}/${SUBNET_WIDTH}"
HOST_ADDR_WITH_MASK="${HOST_ADDR}/${SUBNET_WIDTH}"
IP_HOST="ip -6 -netns ${HOST_NS}"
IP_HOST_EXEC="ip netns exec ${HOST_NS}"
IP_ROUTER="ip -6 -netns ${ROUTER_NS}"
IP_ROUTER_EXEC="ip netns exec ${ROUTER_NS}"
tcpdump_stdout=
tcpdump_stderr=
log_test()
{
local rc=$1
local expected=$2
local msg="$3"
if [ ${rc} -eq ${expected} ]; then
printf " TEST: %-60s [ OK ]\n" "${msg}"
nsuccess=$((nsuccess+1))
else
ret=1
nfail=$((nfail+1))
printf " TEST: %-60s [FAIL]\n" "${msg}"
if [ "${PAUSE_ON_FAIL}" = "yes" ]; then
echo
echo "hit enter to continue, 'q' to quit"
read a
[ "$a" = "q" ] && exit 1
fi
fi
if [ "${PAUSE}" = "yes" ]; then
echo
echo "hit enter to continue, 'q' to quit"
read a
[ "$a" = "q" ] && exit 1
fi
}
setup()
{
set -e
local drop_unsolicited_na=$1
local accept_unsolicited_na=$2
local forwarding=$3
# Setup two namespaces and a veth tunnel across them.
# On end of the tunnel is a router and the other end is a host.
ip netns add ${HOST_NS}
ip netns add ${ROUTER_NS}
${IP_ROUTER} link add ${ROUTER_INTF} type veth \
peer name ${HOST_INTF} netns ${HOST_NS}
# Enable IPv6 on both router and host, and configure static addresses.
# The router here is the DUT
# Setup router configuration as specified by the arguments.
# forwarding=0 case is to check that a non-router
# doesn't add neighbour entries.
ROUTER_CONF=net.ipv6.conf.${ROUTER_INTF}
${IP_ROUTER_EXEC} sysctl -qw \
${ROUTER_CONF}.forwarding=${forwarding}
${IP_ROUTER_EXEC} sysctl -qw \
${ROUTER_CONF}.drop_unsolicited_na=${drop_unsolicited_na}
${IP_ROUTER_EXEC} sysctl -qw \
${ROUTER_CONF}.accept_unsolicited_na=${accept_unsolicited_na}
${IP_ROUTER_EXEC} sysctl -qw ${ROUTER_CONF}.disable_ipv6=0
${IP_ROUTER} addr add ${ROUTER_ADDR_WITH_MASK} dev ${ROUTER_INTF}
# Turn on ndisc_notify on host interface so that
# the host sends unsolicited NAs.
HOST_CONF=net.ipv6.conf.${HOST_INTF}
${IP_HOST_EXEC} sysctl -qw ${HOST_CONF}.ndisc_notify=1
${IP_HOST_EXEC} sysctl -qw ${HOST_CONF}.disable_ipv6=0
${IP_HOST} addr add ${HOST_ADDR_WITH_MASK} dev ${HOST_INTF}
set +e
}
start_tcpdump() {
set -e
tcpdump_stdout=`mktemp`
tcpdump_stderr=`mktemp`
${IP_ROUTER_EXEC} timeout 15s \
tcpdump --immediate-mode -tpni ${ROUTER_INTF} -c 1 \
"icmp6 && icmp6[0] == 136 && src ${HOST_ADDR}" \
> ${tcpdump_stdout} 2> /dev/null
set +e
}
cleanup_tcpdump()
{
set -e
[[ ! -z ${tcpdump_stdout} ]] && rm -f ${tcpdump_stdout}
[[ ! -z ${tcpdump_stderr} ]] && rm -f ${tcpdump_stderr}
tcpdump_stdout=
tcpdump_stderr=
set +e
}
cleanup()
{
cleanup_tcpdump
ip netns del ${HOST_NS}
ip netns del ${ROUTER_NS}
}
link_up() {
set -e
${IP_ROUTER} link set dev ${ROUTER_INTF} up
${IP_HOST} link set dev ${HOST_INTF} up
set +e
}
verify_ndisc() {
local drop_unsolicited_na=$1
local accept_unsolicited_na=$2
local forwarding=$3
neigh_show_output=$(${IP_ROUTER} neigh show \
to ${HOST_ADDR} dev ${ROUTER_INTF} nud stale)
if [ ${drop_unsolicited_na} -eq 0 ] && \
[ ${accept_unsolicited_na} -eq 1 ] && \
[ ${forwarding} -eq 1 ]; then
# Neighbour entry expected to be present for 011 case
[[ ${neigh_show_output} ]]
else
# Neighbour entry expected to be absent for all other cases
[[ -z ${neigh_show_output} ]]
fi
}
test_unsolicited_na_common()
{
# Setup the test bed, but keep links down
setup $1 $2 $3
# Bring the link up, wait for the NA,
# and add a delay to ensure neighbour processing is done.
link_up
start_tcpdump
# Verify the neighbour table
verify_ndisc $1 $2 $3
}
test_unsolicited_na_combination() {
test_unsolicited_na_common $1 $2 $3
test_msg=("test_unsolicited_na: "
"drop_unsolicited_na=$1 "
"accept_unsolicited_na=$2 "
"forwarding=$3")
log_test $? 0 "${test_msg[*]}"
cleanup
}
test_unsolicited_na_combinations() {
# Args: drop_unsolicited_na accept_unsolicited_na forwarding
# Expect entry
test_unsolicited_na_combination 0 1 1
# Expect no entry
test_unsolicited_na_combination 0 0 0
test_unsolicited_na_combination 0 0 1
test_unsolicited_na_combination 0 1 0
test_unsolicited_na_combination 1 0 0
test_unsolicited_na_combination 1 0 1
test_unsolicited_na_combination 1 1 0
test_unsolicited_na_combination 1 1 1
}
###############################################################################
# usage
usage()
{
cat <<EOF
usage: ${0##*/} OPTS
-p Pause on fail
-P Pause after each test before cleanup
EOF
}
###############################################################################
# main
while getopts :pPh o
do
case $o in
p) PAUSE_ON_FAIL=yes;;
P) PAUSE=yes;;
h) usage; exit 0;;
*) usage; exit 1;;
esac
done
# make sure we don't pause twice
[ "${PAUSE}" = "yes" ] && PAUSE_ON_FAIL=no
if [ "$(id -u)" -ne 0 ];then
echo "SKIP: Need root privileges"
exit $ksft_skip;
fi
if [ ! -x "$(command -v ip)" ]; then
echo "SKIP: Could not run test without ip tool"
exit $ksft_skip
fi
if [ ! -x "$(command -v tcpdump)" ]; then
echo "SKIP: Could not run test without tcpdump tool"
exit $ksft_skip
fi
# start clean
cleanup &> /dev/null
test_unsolicited_na_combinations
printf "\nTests passed: %3d\n" ${nsuccess}
printf "Tests failed: %3d\n" ${nfail}
exit $ret
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