Re: [patch RFC net-next v2 2/3] icmp: ICMPV6: Examine invoking packet for Segment Route Headers.

diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index a7c31ab67c5d..dd1fe8a822e3 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c

@@ -818,9 +819,40 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
 	local_bh_enable();
 }
 
+/* Determine if the invoking packet contains a segment routing header.
+ * If it does, extract the true destination address, which is in the
+ * first segment address
+ */
+static void icmpv6_notify_srh(struct sk_buff *skb, struct inet6_skb_parm *opt)
+{
+	__u16 network_header = skb->network_header;
+	struct ipv6_sr_hdr *srh;
+
+	/* Update network header to point to the invoking packet
+	 * inside the ICMP packet, so we can use the seg6_get_srh()
+	 * helper.
+	 */
+	skb_reset_network_header(skb);
+
+	srh = seg6_get_srh(skb, 0);
+	if (!srh)
+		goto out;
+
+	if (srh->type != IPV6_SRCRT_TYPE_4)
+		goto out;
+
+	opt->flags |= IP6SKB_SEG6;
+	opt->srhoff = (unsigned char *)srh - skb->data;
+
+out:
+	/* Restore the network header back to the ICMP packet */
+	skb->network_header = network_header;
+}
+