netdev - [PATCH net-next 5/8] ipv6: icmp6: add drop reason support to ndisc_redirect

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Message-ID: <20230216162842.1633734-6-edumazet@google.com>
Date:   Thu, 16 Feb 2023 16:28:39 +0000
From:   Eric Dumazet <edumazet@...gle.com>
To:     "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     David Ahern <dsahern@...nel.org>, netdev@...r.kernel.org,
        eric.dumazet@...il.com, Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net-next 5/8] ipv6: icmp6: add drop reason support to ndisc_redirect_rcv()

Change ndisc_redirect_rcv() to return a drop reason.

For the moment, return PKT_TOO_SMALL, NOT_SPECIFIED
and values from icmpv6_notify().

More reasons are added later.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/ipv6/ndisc.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 7c8ba308ea4979f46cb22d0132b559278b927a5f..e9776aa6f1675e35273df16e40745779b91d117e 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1601,13 +1601,14 @@ static enum skb_drop_reason ndisc_router_discovery(struct sk_buff *skb)
 	return reason;
 }
 
-static void ndisc_redirect_rcv(struct sk_buff *skb)
+static enum skb_drop_reason ndisc_redirect_rcv(struct sk_buff *skb)
 {
-	u8 *hdr;
-	struct ndisc_options ndopts;
 	struct rd_msg *msg = (struct rd_msg *)skb_transport_header(skb);
 	u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
 				    offsetof(struct rd_msg, opt));
+	struct ndisc_options ndopts;
+	SKB_DR(reason);
+	u8 *hdr;
 
 #ifdef CONFIG_IPV6_NDISC_NODETYPE
 	switch (skb->ndisc_nodetype) {
@@ -1615,31 +1616,31 @@ static void ndisc_redirect_rcv(struct sk_buff *skb)
 	case NDISC_NODETYPE_NODEFAULT:
 		ND_PRINTK(2, warn,
 			  "Redirect: from host or unauthorized router\n");
-		return;
+		return reason;
 	}
 #endif
 
 	if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
 		ND_PRINTK(2, warn,
 			  "Redirect: source address is not link-local\n");
-		return;
+		return reason;
 	}
 
 	if (!ndisc_parse_options(skb->dev, msg->opt, ndoptlen, &ndopts))
-		return;
+		return reason;
 
 	if (!ndopts.nd_opts_rh) {
 		ip6_redirect_no_header(skb, dev_net(skb->dev),
 					skb->dev->ifindex);
-		return;
+		return reason;
 	}
 
 	hdr = (u8 *)ndopts.nd_opts_rh;
 	hdr += 8;
 	if (!pskb_pull(skb, hdr - skb_transport_header(skb)))
-		return;
+		return SKB_DROP_REASON_PKT_TOO_SMALL;
 
-	icmpv6_notify(skb, NDISC_REDIRECT, 0, 0);
+	return icmpv6_notify(skb, NDISC_REDIRECT, 0, 0);
 }
 
 static void ndisc_fill_redirect_hdr_option(struct sk_buff *skb,
@@ -1855,7 +1856,7 @@ enum skb_drop_reason ndisc_rcv(struct sk_buff *skb)
 		break;
 
 	case NDISC_REDIRECT:
-		ndisc_redirect_rcv(skb);
+		reason = ndisc_redirect_rcv(skb);
 		break;
 	}
 
-- 
2.39.1.581.gbfd45094c4-goog