lcd/liblcd: Add skbuff helpers

Signed-off-by: Vikram Narayanan <vikram186@gmail.com>

lcd-domains/liblcd/net/skbuff.c

 #include <lcd_config/pre_hook.h>
 
 #include <linux/skbuff.h>
+#include <linux/etherdevice.h>
 
 #include <lcd_config/post_hook.h>
 
+#if 1
 void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
 		     int size, unsigned int truesize)
 {
@@ -41,3 +43,73 @@ u32 eth_get_headlen(void *data, unsigned int len)
 	return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len);
 }
 EXPORT_SYMBOL(eth_get_headlen);
+
+/**
+ * eth_type_trans - determine the packet's protocol ID.
+ * @skb: received socket data
+ * @dev: receiving network device
+ *
+ * The rule here is that we
+ * assume 802.3 if the type field is short enough to be a length.
+ * This is normal practice and works for any 'now in use' protocol.
+ */
+__be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
+{
+	unsigned short _service_access_point;
+	const unsigned short *sap;
+	const struct ethhdr *eth;
+	static int rate = 0;
+
+	skb->dev = dev;
+	skb_reset_mac_header(skb);
+
+	eth = (struct ethhdr *)skb->data;
+
+	if (skb->len < skb->data_len) {
+		if (!(rate++ % 1000))
+		LIBLCD_ERR("len %d | data_len %d | frags %d I'll drop this packet",
+				skb->len, skb->data_len,
+				skb_shinfo(skb)->nr_frags);
+		return 0x0;
+	}
+	skb_pull_inline(skb, ETH_HLEN);
+
+	if (unlikely(is_multicast_ether_addr_64bits(eth->h_dest))) {
+		if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))
+			skb->pkt_type = PACKET_BROADCAST;
+		else
+			skb->pkt_type = PACKET_MULTICAST;
+	}
+	else if (unlikely(!ether_addr_equal_64bits(eth->h_dest,
+						   dev->dev_addr)))
+		skb->pkt_type = PACKET_OTHERHOST;
+
+	/*
+	 * Some variants of DSA tagging don't have an ethertype field
+	 * at all, so we check here whether one of those tagging
+	 * variants has been configured on the receiving interface,
+	 * and if so, set skb->protocol without looking at the packet.
+	 */
+	if (unlikely(netdev_uses_dsa(dev)))
+		return htons(ETH_P_XDSA);
+
+	if (likely(eth_proto_is_802_3(eth->h_proto)))
+		return eth->h_proto;
+
+	/*
+	 *      This is a magic hack to spot IPX packets. Older Novell breaks
+	 *      the protocol design and runs IPX over 802.3 without an 802.2 LLC
+	 *      layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
+	 *      won't work for fault tolerant netware but does for the rest.
+	 */
+	sap = skb_header_pointer(skb, 0, sizeof(*sap), &_service_access_point);
+	if (sap && *sap == 0xFFFF)
+		return htons(ETH_P_802_3);
+
+	/*
+	 *      Real 802.2 LLC
+	 */
+	return htons(ETH_P_802_2);
+}
+EXPORT_SYMBOL(eth_type_trans);
+#endif