qcacld-3.0: Implement Duplicate Address Detection (DAD)

Implement duplicate address detection at host to check if there
is another device with same IP address as of DUT. Presence of the
devices with same IP as of DUT results in  network connectivity
failures.

Change-Id: Ie74765e5027ceb942098825b5945adaf97f80b70
CRs-Fixed: 2011456

2 files changed, 72 insertions, 0 deletions

diff --git a/core/hdd/src/wlan_hdd_assoc.c b/core/hdd/src/wlan_hdd_assoc.c
index b087f2191c50..81e7be69355b 100644
--- a/core/hdd/src/wlan_hdd_assoc.c
+++ b/core/hdd/src/wlan_hdd_assoc.c
@@ -1675,6 +1675,9 @@ static QDF_STATUS hdd_dis_connect_handler(hdd_adapter_t *pAdapter,
 				pAdapter->sessionId);
 	}
 	wlan_hdd_clear_link_layer_stats(pAdapter);
+
+	pAdapter->dad = false;
+
 	/* Unblock anyone waiting for disconnect to complete */
 	complete(&pAdapter->disconnect_comp_var);
 	hdd_print_bss_info(pHddStaCtx);
diff --git a/core/hdd/src/wlan_hdd_tx_rx.c b/core/hdd/src/wlan_hdd_tx_rx.c
index 4a146c02084b..eb9ee33704b1 100644
--- a/core/hdd/src/wlan_hdd_tx_rx.c
+++ b/core/hdd/src/wlan_hdd_tx_rx.c
@@ -987,6 +987,66 @@ static bool hdd_is_mcast_replay(struct sk_buff *skb)
 }
 
 /**
+ * hdd_get_arp_src_ip() - get ARP packet src IP address
+ * @skb: pointer to sk_buff
+ *
+ * Return: return src IP address field value of ARP packet.
+ */
+static uint32_t hdd_get_arp_src_ip(struct sk_buff *skb)
+{
+	struct arphdr *arp;
+	unsigned char *arp_ptr;
+	uint32_t src_ip;
+
+	arp = (struct arphdr *)skb->data;
+	arp_ptr = (unsigned char *)(arp + 1);
+	arp_ptr += skb->dev->addr_len;
+
+	memcpy(&src_ip, arp_ptr, QDF_IPV4_ADDR_SIZE);
+
+	return src_ip;
+}
+
+/**
+ * hdd_is_duplicate_ip_arp() - duplicate address detection
+ * @skb: pointer to sk_buff
+ *
+ * Return: true if duplicate address detected or false otherwise.
+ */
+static bool hdd_is_duplicate_ip_arp(struct sk_buff *skb)
+{
+	struct in_ifaddr **ifap = NULL;
+	struct in_ifaddr *ifa = NULL;
+	struct in_device *in_dev;
+	uint32_t arp_ip, if_ip;
+
+	if (NULL == skb)
+		return false;
+
+	arp_ip = hdd_get_arp_src_ip(skb);
+
+	if (!skb->dev)
+		return false;
+
+	in_dev = __in_dev_get_rtnl(skb->dev);
+	if (in_dev) {
+		for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;
+			ifap = &ifa->ifa_next) {
+			if (!strcmp(skb->dev->name, ifa->ifa_label))
+				break;
+		}
+	}
+
+	if (ifa && ifa->ifa_local) {
+		if_ip = ifa->ifa_local;
+		if (if_ip == arp_ip)
+			return true;
+	}
+
+	return false;
+}
+
+/**
 * hdd_is_arp_local() - check if local or non local arp
 * @skb: pointer to sk_buff
 *
@@ -1063,6 +1123,7 @@ QDF_STATUS hdd_rx_packet_cbk(void *context, qdf_nbuf_t rxBuf)
 	hdd_station_ctx_t *pHddStaCtx = NULL;
 	unsigned int cpu_index;
 	bool wake_lock = false;
+	bool is_arp = false;
 	bool track_arp = false;
 
 	/* Sanity check on inputs */
@@ -1092,6 +1153,7 @@ QDF_STATUS hdd_rx_packet_cbk(void *context, qdf_nbuf_t rxBuf)
 	skb = (struct sk_buff *)rxBuf;
 
 	if (QDF_NBUF_CB_PACKET_TYPE_ARP == QDF_NBUF_CB_GET_PACKET_TYPE(skb)) {
+		is_arp = true;
 		if (qdf_nbuf_data_is_arp_rsp(skb) &&
 		    (pHddCtx->track_arp_ip == qdf_nbuf_get_arp_src_ip(skb))) {
 			++pAdapter->hdd_stats.hdd_arp_stats.rx_arp_rsp_count;
@@ -1135,6 +1197,13 @@ QDF_STATUS hdd_rx_packet_cbk(void *context, qdf_nbuf_t rxBuf)
 	++pAdapter->stats.rx_packets;
 	pAdapter->stats.rx_bytes += skb->len;
 
+	if (is_arp) {
+		pAdapter->dad |= hdd_is_duplicate_ip_arp(skb);
+		if (pAdapter->dad)
+			QDF_TRACE(QDF_MODULE_ID_HDD_DATA, QDF_TRACE_LEVEL_ERROR,
+				"%s: Duplicate IP detected", __func__);
+	}
+
 	/* Check & drop replayed mcast packets (for IPV6) */
 	if (pHddCtx->config->multicast_replay_filter &&
 			hdd_is_mcast_replay(skb)) {