Use the new libc_random_u32() in ncmlib to replace random_xid().

ncmlib/CMakeLists.txt

@@ -1,13 +1,3 @@
-set(NCMLIB_SRCS
-  malloc.c
-  chroot.c
-  pidfile.c
-  signals.c
-  strlist.c
-  strl.c
-  log.c
-  cap.c
-  io.c
-  )
+file(GLOB NCMLIB_SRCS "*.c")
 
 add_library(ncmlib ${NCMLIB_SRCS})

ncmlib/io.h

@@ -30,6 +30,8 @@
 #ifndef NCM_IO_H_
 #define NCM_IO_H_
 
+#include <sys/socket.h>
+
 int safe_read(int fd, char *buf, int len);
 int safe_write(int fd, const char *buf, int len);
 int safe_sendto(int fd, const char *buf, int len, int flags,

ncmlib/random.c

@@ -0,0 +1,38 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <time.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include "log.h"
+#include "io.h"
+
+// Generate a 32-bit pseudorandom number using libc rand()
+uint32_t libc_random_u32(void)
+{
+    static int initialized;
+    if (initialized)
+        return rand();
+
+    uint32_t seed;
+    int fd = open("/dev/urandom", O_RDONLY);
+    if (fd != -1) {
+        int r = safe_read(fd, (char *)&seed, sizeof seed);
+        if (r == -1) {
+            log_warning("Could not read /dev/urandom: %s", strerror(errno));
+            close(fd);
+            seed = time(0);
+        }
+    } else {
+        log_warning("Could not open /dev/urandom: %s", strerror(errno));
+        seed = time(0);
+    }
+    srand(seed);
+    initialized = 1;
+    return rand();
+}
+
+

ncmlib/random.h

@@ -0,0 +1,6 @@
+#ifndef NCMLIB_RANDOM__
+#define NCMLIB_RANDOM__
+uint32_t libc_random_u32(void);
+
+#endif
+

ndhc/packet.c

@@ -46,6 +46,7 @@
 #include "io.h"
 #include "options.h"
 #include "strl.h"
+#include "random.h"
 
 // Returns fd of new listen socket bound to @ip:@port on interface @inf
 // on success, or -1 on failure.
@@ -636,32 +637,6 @@ void handle_packet(struct client_state_t *cs)
     }
 }
 
-// Generate a 32-bit pseudorandom number
-uint32_t random_xid(void)
-{
-    static int initialized;
-    if (initialized)
-        return rand();
-
-    uint32_t seed;
-    int fd = open("/dev/urandom", O_RDONLY);
-    if (fd != -1) {
-        int r = safe_read(fd, (char *)&seed, sizeof seed);
-        if (r == -1) {
-            log_warning("Could not read /dev/urandom: %s", strerror(errno));
-            close(fd);
-            seed = time(0);
-        }
-    } else {
-        log_warning("Could not open /dev/urandom: %s",
-                    strerror(errno));
-        seed = time(0);
-    }
-    srand(seed);
-    initialized = 1;
-    return rand();
-}
-
 // Initialize a DHCP client packet that will be sent to a server
 static struct dhcpmsg init_packet(char type, uint32_t xid)
 {
@@ -740,7 +715,7 @@ int send_decline(uint32_t xid, uint32_t server, uint32_t requested)
 // Unicasts a DHCP release message
 int send_release(uint32_t server, uint32_t ciaddr)
 {
-    struct dhcpmsg packet = init_packet(DHCPRELEASE, random_xid());
+    struct dhcpmsg packet = init_packet(DHCPRELEASE, libc_random_u32());
     packet.ciaddr = ciaddr;
     add_u32_option(&packet, DHCP_REQUESTED_IP, ciaddr);
     add_u32_option(&packet, DHCP_SERVER_ID, server);

ndhc/packet.h

@@ -77,7 +77,6 @@ struct udp_dhcp_packet {
 
 void change_listen_mode(struct client_state_t *cs, int new_mode);
 void handle_packet(struct client_state_t *cs);
-uint32_t random_xid(void);
 int send_discover(uint32_t xid, uint32_t requested);
 int send_selecting(uint32_t xid, uint32_t server, uint32_t requested);
 int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr);

ndhc/timeout.c

@@ -27,13 +27,14 @@
 #include "packet.h"
 #include "arp.h"
 #include "log.h"
+#include "random.h"
 
 #define DELAY_SEC (((RETRY_DELAY - (RETRY_DELAY / NUMPACKETS)) / NUMPACKETS) + 1)
 static void init_selecting_timeout(struct client_state_t *cs)
 {
     if (cs->packetNum < NUMPACKETS) {
         if (cs->packetNum == 0)
-            cs->xid = random_xid();
+            cs->xid = libc_random_u32();
         /* broadcast */
         send_discover(cs->xid, cs->requestedIP);
         cs->timeout = DELAY_SEC * (cs->packetNum + 1) * 1000;