diff --git a/lib/socket.h b/lib/socket.h
index f1c9a64f..ee7432b0 100644
--- a/lib/socket.h
+++ b/lib/socket.h
@@ -11,6 +11,42 @@
 
 #include "lib/resource.h"
 
-typedef struct birdsock socket;
+typedef struct birdsock {
+  resource r;
+  int type;				/* Socket type */
+  void *data;				/* User data */
+  ip_addr saddr, daddr;			/* IPA_NONE = unspecified */
+  unsigned sport, dport;		/* 0 = unspecified (for IP: protocol type) */
+  int tos;				/* TOS and priority, -1 = default */
+  int ttl;				/* Time To Live, -1 = default */
+  struct iface *iface;			/* Bound to interface */
+
+  byte *rbuf, *rpos;			/* NULL=allocate automatically */
+  unsigned rbsize;
+  void (*rx_hook)(struct birdsock *);	/* NULL=receiving turned off */
+
+  byte *tbuf, *tpos;			/* NULL=allocate automatically */
+  byte *ttx;				/* Internal */
+  unsigned tbsize;
+  void (*tx_hook)(struct birdsock *);
+
+  void (*err_hook)(struct birdsock *, int);
+} socket;
+
+socket *sk_get(pool *);			/* Allocate new socket */
+int sk_open(socket *);			/* Open socket */
+int sk_send(socket *);			/* Try to send queued data, > 0 if succeeded */
+int sk_send_to(socket *, ip_addr, unsigned); /* Send queued data to given destination */
+
+/*
+ *	Socket types		     SA SP DA DP IF  SendTo	(?=may, -=must not, *=must)
+ */
+
+#define SK_TCP_PASSIVE	0	   /* ?  *  -  -  -  -		*/
+#define SK_TCP_ACTIVE	1          /* ?  ?  *  *  -  -		*/
+#define SK_UDP		2          /* ?  ?  -  -  -  ?		*/
+#define SK_UDP_MC       3          /* ?  ?  *  *  *  -		*/
+#define SK_IP		4          /* ?  ?  -  *  -  ?		*/
+#define SK_IP_MC	5          /* ?  ?  *  *  *  -		*/
 
 #endif