add netpacket/packet.h

looks like busybox is going to want it, and apparently some other
low-level network software does too...

include/netpacket/packet.h

+#ifndef _NETPACKET_PACKET_H
+#define _NETPACKET_PACKET_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct sockaddr_ll {
+	unsigned short sll_family, sll_protocol;
+	int sll_ifindex;
+	unsigned short sll_hatype;
+	unsigned char sll_pkttype, sll_halen;
+	unsigned char sll_addr[8];
+};
+
+struct packet_mreq {
+	int mr_ifindex;
+	unsigned short int mr_type,  mr_alen;
+	unsigned char mr_address[8];
+};
+
+#define PACKET_HOST		0
+#define PACKET_BROADCAST	1
+#define PACKET_MULTICAST	2
+#define PACKET_OTHERHOST	3
+#define PACKET_OUTGOING		4
+#define PACKET_LOOPBACK		5
+#define PACKET_FASTROUTE	6
+
+#define PACKET_ADD_MEMBERSHIP		1
+#define PACKET_DROP_MEMBERSHIP		2
+#define	PACKET_RECV_OUTPUT		3
+#define	PACKET_RX_RING			5
+#define	PACKET_STATISTICS		6
+
+#define PACKET_MR_MULTICAST	0
+#define PACKET_MR_PROMISC	1
+#define PACKET_MR_ALLMULTI	2
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif