1 files changed, 51 insertions, 0 deletions
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 95533732f9d6..5089c935c369 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -2196,3 +2196,54 @@ bool cfg80211_iftype_allowed(struct wiphy *wiphy, enum nl80211_iftype iftype,
 	return false;
 }
 EXPORT_SYMBOL(cfg80211_iftype_allowed);
+
+bool cfg80211_is_gratuitous_arp_unsolicited_na(struct sk_buff *skb)
+{
+    const struct ethhdr *eth = (void *)skb->data;
+    const struct {
+        struct arphdr hdr;
+        u8 ar_sha[ETH_ALEN];
+        u8 ar_sip[4];
+        u8 ar_tha[ETH_ALEN];
+        u8 ar_tip[4];
+    } __packed *arp;
+    const struct ipv6hdr *ipv6;
+    const struct icmp6hdr *icmpv6;
+
+    switch (eth->h_proto) {
+    case cpu_to_be16(ETH_P_ARP):
+        /* can't say - but will probably be dropped later anyway */
+        if (!pskb_may_pull(skb, sizeof(*eth) + sizeof(*arp)))
+            return false;
+
+        arp = (void *)(eth + 1);
+
+        if ((arp->hdr.ar_op == cpu_to_be16(ARPOP_REPLY) ||
+             arp->hdr.ar_op == cpu_to_be16(ARPOP_REQUEST)) &&
+            !memcmp(arp->ar_sip, arp->ar_tip, sizeof(arp->ar_sip)))
+            return true;
+        break;
+    case cpu_to_be16(ETH_P_IPV6):
+        /* can't say - but will probably be dropped later anyway */
+        if (!pskb_may_pull(skb, sizeof(*eth) + sizeof(*ipv6) +
+                    sizeof(*icmpv6)))
+            return false;
+
+        ipv6 = (void *)(eth + 1);
+        icmpv6 = (void *)(ipv6 + 1);
+
+        if (icmpv6->icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT &&
+            !memcmp(&ipv6->saddr, &ipv6->daddr, sizeof(ipv6->saddr)))
+            return true;
+        break;
+    default:
+        /*
+         * no need to support other protocols, proxy service isn't
+         * specified for any others
+         */
+        break;
+    }
+
+    return false;
+}
+EXPORT_SYMBOL(cfg80211_is_gratuitous_arp_unsolicited_na);