diff --git a/ndhc/arpping.c b/ndhc/arpping.c
index f76b283..6a2f58b 100644
--- a/ndhc/arpping.c
+++ b/ndhc/arpping.c
@@ -29,9 +29,6 @@ static struct arpMsg arpreply;
 static int arpreply_offset;
 static struct dhcpMessage arp_dhcp_packet;
 
-// from ndhc.c
-void background(void);
-
 /* Returns fd of the arp socket, or -1 on failure. */
 static int arpping(uint32_t test_nip, const uint8_t *safe_mac,
                    uint32_t from_ip, uint8_t *from_mac, const char *interface)
@@ -80,7 +77,6 @@ static int arpping(uint32_t test_nip, const uint8_t *safe_mac,
     return arpfd;
 }
 
-// only called from packet.c
 void arp_check(struct client_state_t *cs, struct dhcpMessage *packet)
 {
     cs->arpPrevState = cs->dhcpState;
@@ -110,7 +106,6 @@ static void arp_failed(struct client_state_t *cs)
     change_listen_mode(cs, LM_RAW);
 }
 
-// only called from timeout.c
 void arp_success(struct client_state_t *cs)
 {
     struct in_addr temp_addr;
diff --git a/ndhc/ndhc.c b/ndhc/ndhc.c
index 7752e70..a8e6935 100644
--- a/ndhc/ndhc.c
+++ b/ndhc/ndhc.c
@@ -95,8 +95,6 @@ struct client_config_t client_config = {
     .arp = "\0",
 };
 
-static char pidfile[MAX_PATH_LENGTH] = PID_FILE_DEFAULT;
-
 static void show_usage(void)
 {
     printf(
@@ -184,21 +182,6 @@ static void perform_release(void)
     cs.timeout = -1;
 }
 
-void background(void)
-{
-    static char called;
-    if (!called && daemon(0, 0) == -1) {
-        perror("fork");
-        exit(EXIT_SUCCESS);
-    }
-    called = 1;  /* Do not fork again. */
-    if (file_exists(pidfile, "w") == -1) {
-        log_line("FATAL - cannot open pidfile for write!");
-        exit(EXIT_FAILURE);
-    }
-    write_pid(pidfile);
-}
-
 static void setup_signals()
 {
     sigset_t mask;
diff --git a/ndhc/sys.c b/ndhc/sys.c
new file mode 100644
index 0000000..7db4a75
--- /dev/null
+++ b/ndhc/sys.c
@@ -0,0 +1,49 @@
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/epoll.h>
+#include "config.h"
+#include "log.h"
+#include "pidfile.h"
+#include "sys.h"
+
+char pidfile[MAX_PATH_LENGTH] = PID_FILE_DEFAULT;
+
+void background(void)
+{
+    static char called;
+    if (!called && daemon(0, 0) == -1) {
+        perror("fork");
+        exit(EXIT_SUCCESS);
+    }
+    called = 1;  /* Do not fork again. */
+    if (file_exists(pidfile, "w") == -1) {
+        log_line("FATAL - cannot open pidfile for write!");
+        exit(EXIT_FAILURE);
+    }
+    write_pid(pidfile);
+}
+
+void epoll_add(struct client_state_t *cs, int fd)
+{
+    struct epoll_event ev;
+    int r;
+    ev.events = EPOLLIN | EPOLLRDHUP | EPOLLERR | EPOLLHUP;
+    ev.data.fd = fd;
+    r = epoll_ctl(cs->epollFd, EPOLL_CTL_ADD, fd, &ev);
+    if (r == -1)
+        suicide("epoll_add failed %s", strerror(errno));
+}
+
+void epoll_del(struct client_state_t *cs, int fd)
+{
+    struct epoll_event ev;
+    int r;
+    ev.events = EPOLLIN | EPOLLRDHUP | EPOLLERR | EPOLLHUP;
+    ev.data.fd = fd;
+    r = epoll_ctl(cs->epollFd, EPOLL_CTL_DEL, fd, &ev);
+    if (r == -1)
+        suicide("epoll_del failed %s", strerror(errno));
+}
diff --git a/ndhc/sys.h b/ndhc/sys.h
new file mode 100644
index 0000000..d55df16
--- /dev/null
+++ b/ndhc/sys.h
@@ -0,0 +1,20 @@
+#ifndef SYS_H_
+#define SYS_H_
+
+#include <sys/time.h>
+#include "ndhc-defines.h"
+
+static inline unsigned long long curms()
+{
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    return tv.tv_sec * 1000ULL + tv.tv_usec / 1000ULL;
+}
+
+extern char pidfile[MAX_PATH_LENGTH];
+
+void background(void);
+void epoll_add(struct client_state_t *cs, int fd);
+void epoll_del(struct client_state_t *cs, int fd);
+
+#endif /* SYS_H_ */
diff --git a/ndhc/timeout.c b/ndhc/timeout.c
index a326b41..2ba2a86 100644
--- a/ndhc/timeout.c
+++ b/ndhc/timeout.c
@@ -9,9 +9,6 @@
 #include "arpping.h"
 #include "log.h"
 
-// from ndhc.c
-void background(void);
-
 static void init_selecting_timeout(struct client_state_t *cs)
 {
     if (cs->packetNum < NUMPACKETS) {