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frr: fix EVPN type-5 forwarding for IPv6 prefixes #633

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Merged
rjarry merged 2 commits into from
Jun 26, 2026
Merged

frr: fix EVPN type-5 forwarding for IPv6 prefixes #633

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1366869
frr: add VXLAN interface redirect for IPv6 nexthops
zeeke Jun 26, 2026
e950717
frr: fix EVPN type-5 forwarding for IPv6 prefixes
zeeke Jun 25, 2026
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23 changes: 19 additions & 4 deletions frr/rt_grout.c
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Original file line number Diff line number Diff line change
Expand Up @@ -736,15 +736,30 @@ grout_add_nexthop(uint32_t nh_id, gr_nh_origin_t origin, const struct nexthop *n
case NEXTHOP_TYPE_IPV6:
case NEXTHOP_TYPE_IPV6_IFINDEX:
l3 = (struct gr_nexthop_info_l3 *)req->nh.info;
l3->af = GR_AF_IP6;
memcpy(&l3->ipv6, &nh->gate.ipv6, sizeof(l3->ipv6));
// EVPN type-5 IPv6 prefixes use v4-mapped nexthops
// (::ffff:X.X.X.X) because the VTEP is always IPv4.
// Store as native IPv4 so vxlan_output uses IPv4
// encapsulation to reach the remote VTEP.
if (IS_MAPPED_IPV6(&nh->gate.ipv6)) {
struct in_addr v4;
ipv4_mapped_ipv6_to_ipv4(&nh->gate.ipv6, &v4);
l3->af = GR_AF_IP4;
l3->ipv4 = v4.s_addr;
vtep.ipa_type = IPADDR_V4;
vtep.ipaddr_v4 = v4;
} else {
l3->af = GR_AF_IP6;
memcpy(&l3->ipv6, &nh->gate.ipv6, sizeof(l3->ipv6));
vtep.ipa_type = IPADDR_V6;
vtep.ipaddr_v6 = nh->gate.ipv6;
}
// Apply cached RMAC from EVPN NEIGH install if available.

@rjarry rjarry Jun 26, 2026

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Same here, keep the comment just above l3vni_rmac_get():

grout/frr/rt_grout.c

Line 741 in 45afc2b

// Apply cached RMAC from EVPN NEIGH install if available.

grout/frr/rt_grout.c

Line 744 in 45afc2b

rmac = l3vni_rmac_get(req->nh.vrf_id, &vtep);

vtep.ipa_type = IPADDR_V6;
vtep.ipaddr_v6 = nh->gate.ipv6;
rmac = l3vni_rmac_get(req->nh.vrf_id, &vtep);
if (rmac != NULL) {
memcpy(&l3->mac, rmac, sizeof(l3->mac));
l3->flags |= GR_NH_F_REMOTE;
if (vxlan_iface_id != GR_IFACE_ID_UNDEF)
req->nh.iface_id = vxlan_iface_id;
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}
break;
case NEXTHOP_TYPE_IFINDEX:
Expand Down
7 changes: 5 additions & 2 deletions modules/ip/datapath/ip_output.c
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Expand Up @@ -135,8 +135,11 @@ ip_output_process(struct rte_graph *graph, struct rte_node *node, void **objs, u
eth_data->dst = l3->mac;
eth_data->ether_type = RTE_BE16(RTE_ETHER_TYPE_IPV4);
if (iface->type == GR_IFACE_TYPE_VXLAN) {
eth_data->vtep.af = GR_AF_IP4;
eth_data->vtep.ipv4 = l3->ipv4;
eth_data->vtep.af = l3->af;
if (l3->af == GR_AF_IP4)
eth_data->vtep.ipv4 = l3->ipv4;
else
eth_data->vtep.ipv6 = l3->ipv6;
} else {
eth_data->vtep.af = GR_AF_UNSPEC;
}
Expand Down
7 changes: 5 additions & 2 deletions modules/ip6/datapath/ip6_output.c
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Expand Up @@ -117,8 +117,11 @@ ip6_output_process(struct rte_graph *graph, struct rte_node *node, void **objs,
eth_data->dst = l3->mac;
eth_data->ether_type = RTE_BE16(RTE_ETHER_TYPE_IPV6);
if (iface->type == GR_IFACE_TYPE_VXLAN) {
eth_data->vtep.af = GR_AF_IP6;
eth_data->vtep.ipv6 = l3->ipv6;
eth_data->vtep.af = l3->af;
if (l3->af == GR_AF_IP4)
eth_data->vtep.ipv4 = l3->ipv4;
else
eth_data->vtep.ipv6 = l3->ipv6;
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} else {
eth_data->vtep.af = GR_AF_UNSPEC;
}
Expand Down
77 changes: 67 additions & 10 deletions smoke/evpn_l3vpn_frr_test.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -7,11 +7,13 @@
# a standalone FRR+Linux peer.
#
# Each side has a VRF with an L3 VNI (1000) and a host connected to a local
# port. BGP EVPN advertises IP prefixes (type-5 routes) and RMAC entries
# (type-2 routes with GR_NH_F_REMOTE nexthops) across the VXLAN overlay.
# port. BGP EVPN advertises IPv4 and IPv6 prefixes (type-5 routes) and RMAC
# entries (type-2 routes with GR_NH_F_REMOTE nexthops) across the VXLAN overlay.
# IPv6 type-5 routes use v4-mapped IPv6 nexthops (::ffff:X.X.X.X) because the
# VTEP is always IPv4.
#
# Success criteria:
# - Both sides exchange EVPN type-5 routes (IP prefixes installed).
# - Both sides exchange EVPN type-5 routes (IPv4 and IPv6 prefixes installed).
# - Host-A and Host-B can ping each other through the L3 VXLAN overlay.
# - RMACs are installed as remote nexthops on the grout side.
#
Expand All @@ -37,9 +39,10 @@
# '--------|---------------|------' '----|--------------|---------'
# | | | |
# | | <------- BGP ----> | |
# 16.0.0.0/24 '---------------------' 48.0.0.0/24
# | underlay |
# .-------|-----------. 172.16.0.0/24 .----------|--------.
# 16.0.0.0/24 '---------------------' 48.0.0.0/24
# fd00:16::/64 underlay fd00:48::/64
# | 172.16.0.0/24 |
# .-------|-----------. .----------|--------.
# | +---+----+ | | +---+----+ |
# | | x-p1 | | | | x-p1 | |
# | +--------+ | <= = = = = = = = = = = = => | +--------+ |
Expand All @@ -61,6 +64,7 @@ start_frr evpn-peer
ip netns exec evpn-peer sysctl -qw net.ipv4.conf.all.forwarding=1
ip netns exec evpn-peer sysctl -qw net.ipv4.conf.all.rp_filter=0
ip netns exec evpn-peer sysctl -qw net.ipv4.conf.default.rp_filter=0
ip netns exec evpn-peer sysctl -qw net.ipv6.conf.all.forwarding=1

move_to_netns x-p0 evpn-peer
ip -n evpn-peer addr add 172.16.0.1/24 dev x-p0
Expand All @@ -83,12 +87,15 @@ ip -n evpn-peer link add p1 type veth peer name x-p1
ip -n evpn-peer link set p1 master tenant
ip -n evpn-peer link set p1 up
ip -n evpn-peer addr add 16.0.0.1/24 dev p1
ip -n evpn-peer addr add fd00:16::1/64 dev p1

netns_add host-a
ip -n evpn-peer link set x-p1 netns host-a
ip -n host-a link set x-p1 up
ip -n host-a addr add 16.0.0.2/24 dev x-p1
ip -n host-a route add default via 16.0.0.1
ip -n host-a addr add fd00:16::2/64 dev x-p1
ip -n host-a -6 route add default via fd00:16::1

# FRR config on the Linux peer
vtysh -N evpn-peer <<-EOF
Expand Down Expand Up @@ -117,8 +124,13 @@ router bgp 65000 vrf tenant
redistribute connected
exit-address-family

address-family ipv6 unicast
redistribute connected
exit-address-family

address-family l2vpn evpn
advertise ipv4 unicast
advertise ipv6 unicast
exit-address-family
exit
EOF
Expand All @@ -131,12 +143,15 @@ grcli interface add vxlan vxlan-l3 vni 1000 local 172.16.0.2 vrf tenant

create_interface p1 vrf tenant
set_ip_address p1 48.0.0.1/24
set_ip_address p1 fd00:48::1/64

netns_add host-b
move_to_netns x-p1 host-b
ip -n host-b addr add 48.0.0.2/24 dev x-p1
ip -n host-b addr add 10.0.0.1/24 dev lo
ip -n host-b route add default via 48.0.0.1
ip -n host-b addr add fd00:48::2/64 dev x-p1
ip -n host-b -6 route add default via fd00:48::1

mark_events

Expand Down Expand Up @@ -167,8 +182,13 @@ router bgp 65000 vrf tenant
redistribute connected
exit-address-family

address-family ipv6 unicast
redistribute connected
exit-address-family

address-family l2vpn evpn
advertise ipv4 unicast
advertise ipv6 unicast
exit-address-family
exit
EOF
Expand All @@ -194,7 +214,7 @@ while ! vtysh -N evpn-peer -c "show evpn vni 1000" | grep -qF "L3"; do
attempts=$((attempts + 1))
done

# -- Wait for EVPN type-5 route exchange ---------------------------------------
# -- Wait for EVPN type-5 route exchange (IPv4) --------------------------------
attempts=0
while ! vtysh -c "show bgp l2vpn evpn route type 5" | grep -qF "16.0.0.0"; do
if [ "$attempts" -ge 5 ]; then
Expand All @@ -217,8 +237,32 @@ while ! vtysh -N evpn-peer -c "show bgp l2vpn evpn route type 5" | grep -qF "48.
attempts=$((attempts + 1))
done

# -- Wait for EVPN type-5 route exchange (IPv6) --------------------------------
attempts=0
while ! vtysh -c "show bgp l2vpn evpn route type 5" | grep -qF "fd00:16::"; do
if [ "$attempts" -ge 5 ]; then
vtysh -c "show bgp l2vpn evpn route type 5"
fail "Grout FRR did not learn type-5 route for fd00:16::/64"
fi
sleep 1
attempts=$((attempts + 1))
done

attempts=0
while ! vtysh -N evpn-peer -c "show bgp l2vpn evpn route type 5" | grep -qF "fd00:48::"; do
if [ "$attempts" -ge 5 ]; then
vtysh -c "show bgp vrf tenant ipv6 unicast"
vtysh -c "show bgp l2vpn evpn route"
vtysh -N evpn-peer -c "show bgp l2vpn evpn route type 5"
fail "Linux peer did not learn type-5 route for fd00:48::/64"
fi
sleep 1
attempts=$((attempts + 1))
done

# -- Wait for routes to be installed in VRF ------------------------------------
wait_event 'route4 add: vrf=tenant 16.0.0.0/24'
wait_event 'route6 add: vrf=tenant fd00:16::/64'

attempts=0
while ! ip -n evpn-peer route show vrf tenant | grep -qF "48.0.0.0/24"; do
Expand All @@ -230,7 +274,17 @@ while ! ip -n evpn-peer route show vrf tenant | grep -qF "48.0.0.0/24"; do
attempts=$((attempts + 1))
done

# -- Check RMAC is set on the route nexthop ------------------------------------
attempts=0
while ! ip -n evpn-peer -6 route show vrf tenant | grep -qF "fd00:48::"; do
if [ "$attempts" -ge 5 ]; then
ip -n evpn-peer -6 route show vrf tenant
fail "Route fd00:48::/64 not installed in peer VRF tenant"
fi
sleep 1
attempts=$((attempts + 1))
done

# -- Check RMAC is set on route nexthops ---------------------------------------
rmac=$(ip netns exec evpn-peer cat /sys/class/net/vxlan-l3/address)

wait_event "nh new: type=L3 id=[0-9]+ iface=vxlan-l3 vrf=tenant origin=zebra family=ipv4 addr=172.16.0.1 mac=$rmac flags=static remote"
Expand All @@ -239,13 +293,16 @@ vtysh -c "show bgp l2vpn evpn route type 5"
grcli route show vrf tenant
grcli nexthop show vrf tenant

# -- Verify L3 connectivity through VXLAN overlay ------------------------------
# -- Verify L3 connectivity through VXLAN overlay (IPv4) -----------------------
ip netns exec host-b ping -i0.1 -c3 -W1 16.0.0.2
ip netns exec host-a ping -i0.1 -c3 -W1 48.0.0.2

# -- Verify L3 connectivity through VXLAN overlay (IPv6) -----------------------
ip netns exec host-b ping -6 -i0.1 -c3 -W1 fd00:16::2
ip netns exec host-a ping -6 -i0.1 -c3 -W1 fd00:48::2

# -- Verify local nexthop uses port, not VXLAN ---------------------------------
# Route to 10.0.0.0/24 (behind host-b) via local gateway 48.0.0.2. The nexthop
# for 48.0.0.2 must use port p1, not the VXLAN interface.
set_ip_route 10.0.0.0/24 48.0.0.2 tenant

grcli ping 10.0.0.1 vrf tenant count 3 delay 10