diff options
| author | Arun Ajith S <aajith@arista.com> | 2022-04-15 08:34:02 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-04-17 13:23:49 +0100 |
| commit | f9a2fb73318eb4dbf8cd84866b8b0dd012d8b116 (patch) | |
| tree | 1441aad939fad8f1112d3bfb24eec862e472f0ee /net/ipv6/ndisc.c | |
| parent | 0339d25a2807d913f5645b8d5e485640915f9702 (diff) | |
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: Arun Ajith S <aajith@arista.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/ndisc.c')
| -rw-r--r-- | net/ipv6/ndisc.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index fcb288b0ae13..254addad0dd3 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -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; |