diff --git a/include/linux/dn.h b/include/linux/dn.h
new file mode 100644
index 0000000..782cae4
--- /dev/null
+++ b/include/linux/dn.h
@@ -0,0 +1,147 @@
+#ifndef _LINUX_DN_H
+#define _LINUX_DN_H
+
+/*
+
+	DECnet Data Structures and Constants
+
+*/
+
+/* 
+ * DNPROTO_NSP can't be the same as SOL_SOCKET, 
+ * so increment each by one (compared to ULTRIX)
+ */
+#define DNPROTO_NSP     2                       /* NSP protocol number       */
+#define DNPROTO_ROU     3                       /* Routing protocol number   */
+#define DNPROTO_NML     4                       /* Net mgt protocol number   */
+#define DNPROTO_EVL     5                       /* Evl protocol number (usr) */
+#define DNPROTO_EVR     6                       /* Evl protocol number (evl) */
+#define DNPROTO_NSPT    7                       /* NSP trace protocol number */
+
+
+#define DN_ADDL		2
+#define DN_MAXADDL	2 /* ULTRIX headers have 20 here, but pathworks has 2 */
+#define DN_MAXOPTL	16
+#define DN_MAXOBJL	16
+#define DN_MAXACCL	40
+#define DN_MAXALIASL	128
+#define DN_MAXNODEL	256
+#define DNBUFSIZE	65023
+
+/* 
+ * SET/GET Socket options  - must match the DSO_ numbers below
+ */
+#define SO_CONDATA      1
+#define SO_CONACCESS    2
+#define SO_PROXYUSR     3
+#define SO_LINKINFO     7
+
+#define DSO_CONDATA     1        /* Set/Get connect data                */
+#define DSO_DISDATA     10       /* Set/Get disconnect data             */
+#define DSO_CONACCESS   2        /* Set/Get connect access data         */
+#define DSO_ACCEPTMODE  4        /* Set/Get accept mode                 */
+#define DSO_CONACCEPT   5        /* Accept deferred connection          */
+#define DSO_CONREJECT   6        /* Reject deferred connection          */
+#define DSO_LINKINFO    7        /* Set/Get link information            */
+#define DSO_STREAM      8        /* Set socket type to stream           */
+#define DSO_SEQPACKET   9        /* Set socket type to sequenced packet */
+#define DSO_MAXWINDOW   11       /* Maximum window size allowed         */
+#define DSO_NODELAY	12       /* Turn off nagle                      */
+#define DSO_CORK        13       /* Wait for more data!                 */
+#define DSO_SERVICES	14       /* NSP Services field                  */
+#define DSO_INFO	15       /* NSP Info field                      */
+#define DSO_MAX         15       /* Maximum option number               */
+
+
+/* LINK States */
+#define LL_INACTIVE	0
+#define LL_CONNECTING	1
+#define LL_RUNNING	2
+#define LL_DISCONNECTING 3
+
+#define ACC_IMMED 0
+#define ACC_DEFER 1
+
+#define SDF_WILD        1                  /* Wild card object          */
+#define SDF_PROXY       2                  /* Addr eligible for proxy   */
+#define SDF_UICPROXY    4                  /* Use uic-based proxy       */
+
+/* Structures */
+
+
+struct dn_naddr 
+{
+	unsigned short		a_len;
+	unsigned char a_addr[DN_MAXADDL];
+};
+
+struct sockaddr_dn
+{
+	unsigned short		sdn_family;
+	unsigned char		sdn_flags;
+	unsigned char		sdn_objnum;
+	unsigned short		sdn_objnamel;
+	unsigned char		sdn_objname[DN_MAXOBJL];
+	struct   dn_naddr	sdn_add;
+};
+#define sdn_nodeaddrl   sdn_add.a_len   /* Node address length  */
+#define sdn_nodeaddr    sdn_add.a_addr  /* Node address         */
+
+
+
+/*
+ * DECnet set/get DSO_CONDATA, DSO_DISDATA (optional data) structure
+ */
+struct optdata_dn {
+        unsigned short  opt_status;     /* Extended status return */
+#define opt_sts opt_status
+        unsigned short  opt_optl;       /* Length of user data    */
+        unsigned char   opt_data[16];   /* User data              */
+};
+
+struct accessdata_dn
+{
+	unsigned char		acc_accl;
+	unsigned char		acc_acc[DN_MAXACCL];
+	unsigned char 		acc_passl;
+	unsigned char		acc_pass[DN_MAXACCL];
+	unsigned char 		acc_userl;
+	unsigned char		acc_user[DN_MAXACCL];
+};
+
+/*
+ * DECnet logical link information structure
+ */
+struct linkinfo_dn {
+        unsigned short  idn_segsize;    /* Segment size for link */
+        unsigned char   idn_linkstate;  /* Logical link state    */
+};
+
+/*
+ * Ethernet address format (for DECnet)
+ */
+union etheraddress {
+        unsigned char dne_addr[6];             /* Full ethernet address */
+  struct {
+                unsigned char dne_hiord[4];    /* DECnet HIORD prefix   */
+                unsigned char dne_nodeaddr[2]; /* DECnet node address   */
+  } dne_remote;
+};
+
+
+/*
+ * DECnet physical socket address format
+ */
+struct dn_addr {
+        unsigned short dna_family;      /* AF_DECnet               */
+        union etheraddress dna_netaddr; /* DECnet ethernet address */
+};
+
+#define DECNET_IOCTL_BASE 0x89 /* PROTOPRIVATE range */
+
+#define SIOCSNETADDR  _IOW(DECNET_IOCTL_BASE, 0xe0, struct dn_naddr)
+#define SIOCGNETADDR  _IOR(DECNET_IOCTL_BASE, 0xe1, struct dn_naddr)
+#define OSIOCSNETADDR _IOW(DECNET_IOCTL_BASE, 0xe0, int)
+#define OSIOCGNETADDR _IOR(DECNET_IOCTL_BASE, 0xe1, int)
+
+#endif /* _LINUX_DN_H */