From: Eric Dumazet <edumazet@google.com>
Date: Thu, 16 Feb 2023 16:28:41 +0000 (+0000)
Subject: ipv6: icmp6: add SKB_DROP_REASON_IPV6_NDISC_NS_OTHERHOST
X-Git-Tag: io_uring-6.3-2023-03-03~13^2~30^2~1
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=c34b8bb11ebc135e970653bd6fc8e3f863fb6a81;p=linux-2.6-block.git

ipv6: icmp6: add SKB_DROP_REASON_IPV6_NDISC_NS_OTHERHOST

Hosts can often receive neighbour discovery messages
that are not for them.

Use a dedicated drop reason to make clear the packet is dropped
for this normal case.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/include/net/dropreason.h b/include/net/dropreason.h
index 239a5c0ea83e..c0a3ea806cd5 100644
--- a/include/net/dropreason.h
+++ b/include/net/dropreason.h
@@ -77,6 +77,7 @@
 	FN(IPV6_NDISC_HOP_LIMIT)	\
 	FN(IPV6_NDISC_BAD_CODE)		\
 	FN(IPV6_NDISC_BAD_OPTIONS)	\
+	FN(IPV6_NDISC_NS_OTHERHOST)	\
 	FNe(MAX)
 
 /**
@@ -333,6 +334,10 @@ enum skb_drop_reason {
 	SKB_DROP_REASON_IPV6_NDISC_BAD_CODE,
 	/** @SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS: invalid NDISC options. */
 	SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS,
+	/** @SKB_DROP_REASON_IPV6_NDISC_NS_OTHERHOST: NEIGHBOUR SOLICITATION
+	 * for another host.
+	 */
+	SKB_DROP_REASON_IPV6_NDISC_NS_OTHERHOST,
 	/**
 	 * @SKB_DROP_REASON_MAX: the maximum of drop reason, which shouldn't be
 	 * used as a real 'reason'
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index b47e845d66eb..c4be62c99f73 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -921,8 +921,10 @@ have_ifp:
 					pneigh_enqueue(&nd_tbl, idev->nd_parms, n);
 				goto out;
 			}
-		} else
+		} else {
+			SKB_DR_SET(reason, IPV6_NDISC_NS_OTHERHOST);
 			goto out;
+		}
 	}
 
 	if (is_router < 0)