diff --git a/ndhc/ifset.c b/ndhc/ifset.c
index 0c35924..61570e8 100644
--- a/ndhc/ifset.c
+++ b/ndhc/ifset.c
@@ -53,6 +53,7 @@
 #include "log.h"
 #include "ifch_proto.h"
 #include "strl.h"
+#include "nl.h"
 
 static int set_if_flag(short flag)
 {
@@ -88,30 +89,6 @@ static int set_if_flag(short flag)
     return ret;
 }
 
-#define NLMSG_TAIL(nmsg)                               \
-    ((struct rtattr *) (((uint8_t*) (nmsg)) +          \
-                        NLMSG_ALIGN((nmsg)->nlmsg_len)))
-
-static int add_rtattr(struct nlmsghdr *n, size_t max_length, int type,
-                      const void *data, size_t data_length)
-{
-    size_t length;
-    struct rtattr *rta;
-
-    length = RTA_LENGTH(data_length);
-
-    if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length) > max_length)
-        return -E2BIG;
-
-    rta = NLMSG_TAIL(n);
-    rta->rta_type = type;
-    rta->rta_len = length;
-    memcpy(RTA_DATA(rta), data, data_length);
-    n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length);
-
-    return 0;
-}
-
 // 32-bit position values are relatively prime to 37, so the residue mod37
 // gives a unique mapping for each value.  Gives correct result for v=0.
 static int trailz(uint32_t v)
@@ -192,14 +169,14 @@ void perform_ip_subnet_bcast(const char *str_ipaddr,
     ifaddrmsg->ifa_scope = RT_SCOPE_UNIVERSE;
     ifaddrmsg->ifa_index = client_config.ifindex;
 
-    if (add_rtattr(header, sizeof request, IFA_LOCAL,
-                   &ipaddr, sizeof ipaddr) < 0) {
+    if (nl_add_rtattr(header, sizeof request, IFA_LOCAL,
+                      &ipaddr, sizeof ipaddr) < 0) {
         log_line("%s: (%s) couldn't add IFA_LOCAL to nlmsg",
                  client_config.interface, __func__);
         return;
     }
-    if (add_rtattr(header, sizeof request, IFA_BROADCAST,
-                   &bcast, sizeof bcast) < 0) {
+    if (nl_add_rtattr(header, sizeof request, IFA_BROADCAST,
+                      &bcast, sizeof bcast) < 0) {
         log_line("%s: (%s) couldn't add IFA_BROADCAST to nlmsg",
                  client_config.interface, __func__);
         return;
diff --git a/ndhc/nl.c b/ndhc/nl.c
index 0c41c3b..4c9473e 100644
--- a/ndhc/nl.c
+++ b/ndhc/nl.c
@@ -1,6 +1,6 @@
 /* nl.c - low level netlink protocol functions
  *
- * Copyright (c) 2011 Nicholas J. Kain <njkain at gmail dot com>
+ * Copyright (c) 2011-2014 Nicholas J. Kain <njkain at gmail dot com>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -30,6 +30,7 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <arpa/inet.h>
+#include <linux/rtnetlink.h>
 #include <unistd.h>
 #include <string.h>
 #include <fcntl.h>
@@ -37,6 +38,30 @@
 #include "log.h"
 #include "nl.h"
 
+#define NLMSG_TAIL(nmsg)                               \
+    ((struct rtattr *) (((uint8_t*) (nmsg)) +          \
+                        NLMSG_ALIGN((nmsg)->nlmsg_len)))
+
+int nl_add_rtattr(struct nlmsghdr *n, size_t max_length, int type,
+                  const void *data, size_t data_length)
+{
+    size_t length;
+    struct rtattr *rta;
+
+    length = RTA_LENGTH(data_length);
+
+    if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length) > max_length)
+        return -E2BIG;
+
+    rta = NLMSG_TAIL(n);
+    rta->rta_type = type;
+    rta->rta_len = length;
+    memcpy(RTA_DATA(rta), data, data_length);
+    n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length);
+
+    return 0;
+}
+
 void nl_attr_parse(const struct nlmsghdr *nlh, size_t offset,
                    nl_attr_parse_fn workfn, void *data)
 {
diff --git a/ndhc/nl.h b/ndhc/nl.h
index 5bb74e6..2c5de75 100644
--- a/ndhc/nl.h
+++ b/ndhc/nl.h
@@ -1,6 +1,6 @@
 /* nl.h - low level netlink protocol functions
  *
- * Copyright (c) 2011 Nicholas J. Kain <njkain at gmail dot com>
+ * Copyright (c) 2011-2014 Nicholas J. Kain <njkain at gmail dot com>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -66,16 +66,18 @@ static inline int nlmsg_get_error(const struct nlmsghdr *nlh)
     return err->error & 0x7fffffff;
 }
 
+extern int nl_add_rtattr(struct nlmsghdr *n, size_t max_length, int type,
+                         const void *data, size_t data_length);
 typedef int (*nl_attr_parse_fn)(struct nlattr *attr, int type, void *data);
-void nl_attr_parse(const struct nlmsghdr *nlh, size_t offset,
-                   nl_attr_parse_fn workfn, void *data);
+extern void nl_attr_parse(const struct nlmsghdr *nlh, size_t offset,
+                          nl_attr_parse_fn workfn, void *data);
 
-ssize_t nl_recv_buf(int fd, char *buf, size_t blen);
+extern ssize_t nl_recv_buf(int fd, char *buf, size_t blen);
 
 typedef int (*nlmsg_foreach_fn)(const struct nlmsghdr *, void *);
-int nl_foreach_nlmsg(char *buf, size_t blen, uint32_t portid,
-                     nlmsg_foreach_fn pfn, void *fnarg);
+extern int nl_foreach_nlmsg(char *buf, size_t blen, uint32_t portid,
+                            nlmsg_foreach_fn pfn, void *fnarg);
 
-int nl_open(int nltype, int nlgroup, int *nlportid);
+extern int nl_open(int nltype, int nlgroup, int *nlportid);
 
 #endif /* NK_NL_H_ */