diff --git a/Makefile b/Makefile
index f1a1bb0..d312368 100755
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,10 @@
 
 BIN=smartdns 
-OBJS=smartdns.o fast_ping.o 
-CFLAGS=-g -O0
-CFLAGS=-Iinclude
+OBJS=smartdns.o fast_ping.o lib/bitops.o
+CFLAGS=-g -O0 -Wall
+CFLAGS +=-Iinclude
+CXXFLAGS=-g -O0 -Wall -std=c++11
+CXXFLAGS +=-Iinclude
 
 .PHONY: all
 
diff --git a/fast_ping.c b/fast_ping.c
index 73b39aa..35f7eef 100755
--- a/fast_ping.c
+++ b/fast_ping.c
@@ -2,6 +2,7 @@
 #include "atomic.h"
 #include "hashtable.h"
 #include <errno.h>
+#include <arpa/inet.h>
 #include <linux/filter.h>
 #include <netdb.h>
 #include <netinet/icmp6.h>
@@ -45,6 +46,10 @@ struct ping_host_struct {
 
     int fd;
     unsigned int seq;
+    struct timeval last;
+    int interval;
+    int timeout;
+    int send;
     struct sockaddr_storage addr;
     socklen_t addr_len;
     struct fast_ping_packet packet;
@@ -54,7 +59,7 @@ struct fast_ping_struct {
     int run;
     pthread_t tid;
     pthread_mutex_t lock;
-    int ident;
+    unsigned short ident;
 
     int epoll_fd;
     int fd_icmp;
@@ -82,7 +87,7 @@ uint16_t _fast_ping_checksum(uint16_t *header, size_t len)
     return htons(~((sum >> 16) + (sum & 0xffff)));
 }
 
-int fast_ping_result_callback(fast_ping_result result)
+void fast_ping_result_callback(fast_ping_result result)
 {
     ping_callback = result;
 }
@@ -148,7 +153,7 @@ void _fast_ping_install_filter_v4(int sock)
     }
 }
 
-static struct addrinfo *_fast_ping_getaddr(const u_char *host, int type, int protocol)
+static struct addrinfo *_fast_ping_getaddr(const char *host, int type, int protocol)
 {
     struct addrinfo hints;
     struct addrinfo *result = NULL;
@@ -170,7 +175,7 @@ errout:
     return NULL;
 }
 
-static int _fast_ping_getdomain(const u_char *host)
+static int _fast_ping_getdomain(const char *host)
 {
     struct addrinfo hints;
     struct addrinfo *result = NULL;
@@ -197,12 +202,12 @@ errout:
     return -1;
 }
 
-int _fast_ping_host_get(struct ping_host_struct *ping_host)
+static void _fast_ping_host_get(struct ping_host_struct *ping_host)
 {
     atomic_inc(&ping_host->ref);
 }
 
-int _fast_ping_host_put(struct ping_host_struct *ping_host)
+static void _fast_ping_host_put(struct ping_host_struct *ping_host)
 {
     pthread_mutex_lock(&ping.map_lock);
     if (atomic_dec_and_test(&ping_host->ref)) {
@@ -214,7 +219,7 @@ int _fast_ping_host_put(struct ping_host_struct *ping_host)
     pthread_mutex_unlock(&ping.map_lock);
 
     if (ping_host == NULL) {
-        return -1;
+        return ;
     }
 
     free(ping_host);
@@ -280,34 +285,48 @@ errout:
 
 static int _fast_ping_sendping(struct ping_host_struct *ping_host)
 {
+    int ret = -1;
+
     if (ping_host->type == AF_INET) {
-        return _fast_ping_sendping_v4(ping_host);
+        ret = _fast_ping_sendping_v4(ping_host);
     } else if (ping_host->type == AF_INET6) {
-        return _fast_ping_sendping_v6(ping_host);
+        ret = _fast_ping_sendping_v6(ping_host);
     }
 
-    return -1;
+    if (ret != 0) {
+        return ret;
+    }
+
+    ping_host->send = 1;
+    gettimeofday(&ping_host->last, 0);
+
+    return 0;
 }
 
 static int _fast_ping_create_sock(int protocol)
 {
-    int fd;
+    int fd = -1;
     struct ping_host_struct *icmp_host = NULL;
     struct epoll_event event;
 
-    fd = socket(AF_INET, SOCK_RAW, protocol);
-    if (fd < 0) {
-        fprintf(stderr, "create icmp socket failed.\n");
-        goto errout;
-    }
     switch (protocol) {
     case IPPROTO_ICMP:
+        fd = socket(AF_INET, SOCK_RAW, protocol);
+        if (fd < 0) {
+            fprintf(stderr, "create icmp socket failed.\n");
+            goto errout;
+        }
         _fast_ping_install_filter_v4(fd);
         icmp_host = &ping.icmp_host;
         break;
     case IPPROTO_ICMPV6:
+        fd = socket(AF_INET6, SOCK_RAW, protocol);
+        if (fd < 0) {
+            fprintf(stderr, "create icmp socket failed.\n");
+            goto errout;
+        }
         _fast_ping_install_filter_v6(fd);
-        icmp_host = &ping.icmp_host;
+        icmp_host = &ping.icmp6_host;
         break;
     }
 
@@ -371,7 +390,6 @@ int fast_ping_start(const char *host, int timeout, void *userptr)
     struct addrinfo *gai = NULL;
     int domain = -1;
     int icmp_proto = 0;
-    char ip[PING_MAX_HOSTLEN];
     uint32_t hostkey;
     uint32_t addrkey;
 
@@ -402,17 +420,20 @@ int fast_ping_start(const char *host, int timeout, void *userptr)
         goto errout;
     }
 
-    memset(ping_host, 0, sizeof(ping_host));
+    int interval = 1000;
+    memset(ping_host, 0, sizeof(*ping_host));
     strncpy(ping_host->host, host, PING_MAX_HOSTLEN);
     ping_host->type = domain;
     ping_host->fd = _fast_ping_create_icmp(icmp_proto);
+    ping_host->timeout = timeout;
+    ping_host->interval = interval;
     memcpy(&ping_host->addr, gai->ai_addr, gai->ai_addrlen);
     ping_host->addr_len = gai->ai_addrlen;
 
     atomic_set(&ping_host->ref, 0);
 
     hostkey = hash_string(ping_host->host);
-	addrkey = jhash(&ping_host->addr, ping_host->addr_len, 0);
+    addrkey = jhash(&ping_host->addr, ping_host->addr_len, 0);
     pthread_mutex_lock(&ping.map_lock);
     _fast_ping_host_get(ping_host);
     hash_add(ping.hostmap, &ping_host->host_node, hostkey);
@@ -467,12 +488,10 @@ void tv_sub(struct timeval *out, struct timeval *in)
 
 static int _fast_ping_icmp6_packet(struct ping_host_struct *ping_host, u_char *packet_data, int data_len, struct timeval *tvrecv)
 {
-    int hlen;
     int icmp_len;
     struct fast_ping_packet *packet = (struct fast_ping_packet *)packet_data;
     struct icmp6_hdr *icmp6 = &packet->icmp6;
     struct timeval tvresult = *tvrecv;
-    double rtt;
 
     if (icmp6->icmp6_type != ICMP6_ECHO_REPLY) {
         return -1;
@@ -489,7 +508,7 @@ static int _fast_ping_icmp6_packet(struct ping_host_struct *ping_host, u_char *p
 
     struct timeval *tvsend = &packet->msg.tv;
     tv_sub(&tvresult, tvsend);
-    ping_callback(ping_host->host, ping_host->seq, &tvresult, ping_host->userptr);
+    ping_callback(ping_host->host, PING_RESULT_RESPONSE, ping_host->seq, &tvresult, ping_host->userptr);
 
     return 0;
 }
@@ -527,7 +546,7 @@ static int _fast_ping_icmp_packet(struct ping_host_struct *ping_host, u_char *pa
     struct timeval *tvsend = &packet->msg.tv;
     tv_sub(&tvresult, tvsend);
 
-    ping_callback(ping_host->host, ping_host->seq, &tvresult, ping_host->userptr);
+    ping_callback(ping_host->host, PING_RESULT_RESPONSE, ping_host->seq, &tvresult, ping_host->userptr);
 
     return 0;
 }
@@ -551,14 +570,7 @@ errout:
     return -1;
 }
 
-static int _fast_ping_create_tcp(struct ping_host_struct *ping_host)
-{
-    return -1;
-}
-
-static int _fast_ping_ping_host(struct ping_host_struct *ping_host) {}
-
-static int _fast_ping_gethost_by_addr(u_char *host, struct sockaddr *addr, socklen_t addr_len)
+static int _fast_ping_gethost_by_addr(char *host, struct sockaddr *addr, socklen_t addr_len)
 {
     struct sockaddr_storage *addr_store = (struct sockaddr_storage *)addr;
     host[0] = 0;
@@ -603,7 +615,7 @@ static int _fast_ping_process(struct ping_host_struct *ping_host, struct timeval
         goto errout;
     }
 
-	addrkey = jhash(&from, from_len, 0);
+    addrkey = jhash(&from, from_len, 0);
     pthread_mutex_lock(&ping.map_lock);
     hash_for_each_possible(ping.addrmap, recv_ping_host, addr_node, addrkey)
     {
@@ -617,6 +629,8 @@ static int _fast_ping_process(struct ping_host_struct *ping_host, struct timeval
         return -1;
     }
 
+    recv_ping_host->send = 0;
+
     _fast_ping_recvping(recv_ping_host, inpacket, len, now);
     return 0;
 errout:
@@ -628,10 +642,24 @@ static void _fast_ping_period_run()
     struct ping_host_struct *ping_host;
     struct hlist_node *tmp;
     int i = 0;
+    struct timeval now;
+    struct timeval interval;
+    uint64_t millisecond;
+    gettimeofday(&now, 0);
+
     pthread_mutex_lock(&ping.map_lock);
     hash_for_each_safe(ping.addrmap, i, tmp, ping_host, addr_node)
     {
-        _fast_ping_sendping(ping_host);
+        interval = now;
+        tv_sub(&interval, &ping_host->last);
+        millisecond = interval.tv_sec * 1000 + interval.tv_usec / 1000;
+        if (millisecond > ping_host->timeout && ping_host->send == 1) {
+            ping_callback(ping_host->host, PING_RESULT_TIMEOUT, ping_host->seq, &interval, ping_host->userptr);  
+            ping_host->send = 0;          
+        }
+        if (millisecond >= ping_host->interval) {
+            _fast_ping_sendping(ping_host);
+        } 
     }
     pthread_mutex_unlock(&ping.map_lock);
 }
@@ -643,14 +671,19 @@ static void *_fast_ping_work(void *arg)
     int i;
     struct timeval last = { 0 };
     struct timeval now = { 0 };
+    struct timeval diff = {0};
+    uint millisec = 0;
 
     while (ping.run) {
-        if (last.tv_sec != now.tv_sec) {
+        diff = now;
+        tv_sub(&diff, &last);
+        millisec = diff.tv_sec * 1000 + diff.tv_usec / 1000;
+        if (millisec >= 100) {
             _fast_ping_period_run();
             last = now;
         }
 
-        num = epoll_wait(ping.epoll_fd, events, PING_MAX_EVENTS, 1000);
+        num = epoll_wait(ping.epoll_fd, events, PING_MAX_EVENTS, 100);
         if (num < 0) {
             gettimeofday(&now, 0);
             usleep(100000);
@@ -727,7 +760,7 @@ errout:
     return -1;
 }
 
-int fast_ping_exit()
+void fast_ping_exit()
 {
     if (ping.tid > 0) {
         void *ret = NULL;
@@ -737,12 +770,12 @@ int fast_ping_exit()
 
     if (ping.fd_icmp > 0) {
         close(ping.fd_icmp);
-        ping.fd_icmp < 0;
+        ping.fd_icmp = -1;
     }
 
     if (ping.fd_icmp6 > 0) {
         close(ping.fd_icmp6);
-        ping.fd_icmp6 < 0;
+        ping.fd_icmp6 = -1;
     }
 
     pthread_mutex_destroy(&ping.lock);
diff --git a/fast_ping.h b/fast_ping.h
index 9220d7d..ac9a41c 100755
--- a/fast_ping.h
+++ b/fast_ping.h
@@ -13,8 +13,13 @@ typedef enum {
 	FAST_PING_UDP
 } FAST_PING_TYPE;
 
-typedef void (*fast_ping_result)(const char *host, int seqno, struct timeval *tv, void *userptr);
-int fast_ping_result_callback(fast_ping_result result);
+typedef enum {
+	PING_RESULT_RESPONSE = 1,
+	PING_RESULT_TIMEOUT = 2,
+} FAST_PING_RESULT;
+
+typedef void (*fast_ping_result)(const char *host, FAST_PING_RESULT result, int seqno, struct timeval *tv, void *userptr);
+void fast_ping_result_callback(fast_ping_result result);
 
 int fast_ping_start(const char *host, int timeout, void *userptr);
 
@@ -22,7 +27,7 @@ int fast_ping_stop(const char *host);
 
 int fast_ping_init();
 
-int fast_ping_exit();
+void fast_ping_exit();
 
 #ifdef __cpluscplus
 }
diff --git a/include/atomic.h b/include/atomic.h
index c82f5d3..2249b39 100755
--- a/include/atomic.h
+++ b/include/atomic.h
@@ -2,6 +2,7 @@
 #ifndef _GENERIC_ATOMIC_H
 #define _GENERIC_ATOMIC_H
 
+
 /* Check GCC version, just to be safe */
 #if !defined(__GNUC__) || (__GNUC__ < 4) || (__GNUC_MINOR__ < 1)
 # error atomic.h works only with GCC newer than version 4.1
diff --git a/include/bitmap.h b/include/bitmap.h
index 8170981..48c2cda 100644
--- a/include/bitmap.h
+++ b/include/bitmap.h
@@ -5,6 +5,8 @@
 #include <string.h>
 #include <stdlib.h>
 #include "bitops.h"
+#include "findbit.h"
+
 
 #define DECLARE_BITMAP(name,bits) \
 	unsigned long name[BITS_TO_LONGS(bits)]
@@ -101,7 +103,7 @@ static inline int test_and_set_bit(int nr, unsigned long *addr)
  */
 static inline unsigned long *bitmap_alloc(int nbits)
 {
-	return calloc(1, BITS_TO_LONGS(nbits) * sizeof(unsigned long));
+	return (unsigned long *)calloc(1, BITS_TO_LONGS(nbits) * sizeof(unsigned long));
 }
 
 /*
diff --git a/include/bitops.h b/include/bitops.h
index 8fb2e93..b33d7b3 100644
--- a/include/bitops.h
+++ b/include/bitops.h
@@ -2,6 +2,10 @@
 #ifndef _GENERIC_BITOPS_H_
 #define _GENERIC_BITOPS_H_
 
+#include <unistd.h>
+#include <stdint.h>
+#include "gcc_builtin.h"
+
 #ifndef __WORDSIZE
 #define __WORDSIZE (__SIZEOF_LONG__ * 8)
 #endif
@@ -24,6 +28,164 @@ extern unsigned int __sw_hweight32(unsigned int w);
 extern unsigned long __sw_hweight64(uint64_t w);
 
 
+#define ffz(x)  __ffs(~(x))
+
+/**
+ * fls - find last (most-significant) bit set
+ * @x: the word to search
+ *
+ * This is defined the same way as ffs.
+ * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
+ */
+
+/**
+ * __ffs - find first bit in word.
+ * @word: The word to search
+ *
+ * Undefined if no bit exists, so code should check against 0 first.
+ */
+static inline unsigned long __ffs(unsigned long word)
+{
+	int num = 0;
+
+#if __BITS_PER_LONG == 64
+	if ((word & 0xffffffff) == 0) {
+		num += 32;
+		word >>= 32;
+	}
+#endif
+	if ((word & 0xffff) == 0) {
+		num += 16;
+		word >>= 16;
+	}
+	if ((word & 0xff) == 0) {
+		num += 8;
+		word >>= 8;
+	}
+	if ((word & 0xf) == 0) {
+		num += 4;
+		word >>= 4;
+	}
+	if ((word & 0x3) == 0) {
+		num += 2;
+		word >>= 2;
+	}
+	if ((word & 0x1) == 0)
+		num += 1;
+	return num;
+}
+
+static inline int fls(int x)
+{
+	int r = 32;
+
+	if (!x)
+		return 0;
+	if (!(x & 0xffff0000u)) {
+		x <<= 16;
+		r -= 16;
+	}
+	if (!(x & 0xff000000u)) {
+		x <<= 8;
+		r -= 8;
+	}
+	if (!(x & 0xf0000000u)) {
+		x <<= 4;
+		r -= 4;
+	}
+	if (!(x & 0xc0000000u)) {
+		x <<= 2;
+		r -= 2;
+	}
+	if (!(x & 0x80000000u)) {
+		x <<= 1;
+		r -= 1;
+	}
+	return r;
+}
+
+/**
+ * fls64 - find last set bit in a 64-bit word
+ * @x: the word to search
+ *
+ * This is defined in a similar way as the libc and compiler builtin
+ * ffsll, but returns the position of the most significant set bit.
+ *
+ * fls64(value) returns 0 if value is 0 or the position of the last
+ * set bit if value is nonzero. The last (most significant) bit is
+ * at position 64.
+ */
+#if BITS_PER_LONG == 32
+static inline int fls64(uint64_t x)
+{
+	uint32_t h = x >> 32;
+	if (h)
+		return fls(h) + 32;
+	return fls(x);
+}
+#elif BITS_PER_LONG == 64
+static inline int fls64(uint64_t x)
+{
+	if (x == 0)
+		return 0;
+	return __fls(x) + 1;
+}
+#else
+#error BITS_PER_LONG not 32 or 64
+#endif
+
+/**
+ * hweightN - returns the hamming weight of a N-bit word
+ * @x: the word to weigh
+ *
+ * The Hamming Weight of a number is the total number of bits set in it.
+ */
+
+static inline unsigned int hweight32(unsigned int w)
+{
+	unsigned int res = w - ((w >> 1) & 0x55555555);
+	res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
+	res = (res + (res >> 4)) & 0x0F0F0F0F;
+	res = res + (res >> 8);
+	return (res + (res >> 16)) & 0x000000FF;
+}
+
+static inline unsigned int hweight16(unsigned int w)
+{
+	unsigned int res = w - ((w >> 1) & 0x5555);
+	res = (res & 0x3333) + ((res >> 2) & 0x3333);
+	res = (res + (res >> 4)) & 0x0F0F;
+	return (res + (res >> 8)) & 0x00FF;
+}
+
+static inline unsigned int hweight8(unsigned int w)
+{
+	unsigned int res = w - ((w >> 1) & 0x55);
+	res = (res & 0x33) + ((res >> 2) & 0x33);
+	return (res + (res >> 4)) & 0x0F;
+}
+
+static inline unsigned long hweight64(uint64_t w)
+{
+#if BITS_PER_LONG == 32
+	return hweight32((unsigned int)(w >> 32)) + hweight32((unsigned int)w);
+#elif BITS_PER_LONG == 64
+#ifdef ARCH_HAS_FAST_MULTIPLIER
+	w -= (w >> 1) & 0x5555555555555555ul;
+	w =  (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul);
+	w =  (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful;
+	return (w * 0x0101010101010101ul) >> 56;
+#else
+	uint64_t res = w - ((w >> 1) & 0x5555555555555555ul);
+	res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
+	res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;
+	res = res + (res >> 8);
+	res = res + (res >> 16);
+	return (res + (res >> 32)) & 0x00000000000000FFul;
+#endif
+#endif
+}
+
 #define for_each_set_bit(bit, addr, size) \
 	for ((bit) = find_first_bit((addr), (size));		\
 	     (bit) < (size);					\
diff --git a/include/findbit.h b/include/findbit.h
new file mode 100644
index 0000000..cac0939
--- /dev/null
+++ b/include/findbit.h
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TOOLS_LINUX_ASM_GENERIC_BITOPS_FIND_H_
+#define _TOOLS_LINUX_ASM_GENERIC_BITOPS_FIND_H_
+
+#ifndef find_next_bit
+/**
+ * find_next_bit - find the next set bit in a memory region
+ * @addr: The address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The bitmap size in bits
+ *
+ * Returns the bit number for the next set bit
+ * If no bits are set, returns @size.
+ */
+extern unsigned long find_next_bit(const unsigned long *addr, unsigned long
+		size, unsigned long offset);
+#endif
+
+#ifndef find_next_and_bit
+/**
+ * find_next_and_bit - find the next set bit in both memory regions
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The bitmap size in bits
+ *
+ * Returns the bit number for the next set bit
+ * If no bits are set, returns @size.
+ */
+extern unsigned long find_next_and_bit(const unsigned long *addr1,
+		const unsigned long *addr2, unsigned long size,
+		unsigned long offset);
+#endif
+
+#ifndef find_next_zero_bit
+
+/**
+ * find_next_zero_bit - find the next cleared bit in a memory region
+ * @addr: The address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The bitmap size in bits
+ *
+ * Returns the bit number of the next zero bit
+ * If no bits are zero, returns @size.
+ */
+unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
+				 unsigned long offset);
+#endif
+
+#ifndef find_first_bit
+
+/**
+ * find_first_bit - find the first set bit in a memory region
+ * @addr: The address to start the search at
+ * @size: The maximum number of bits to search
+ *
+ * Returns the bit number of the first set bit.
+ * If no bits are set, returns @size.
+ */
+extern unsigned long find_first_bit(const unsigned long *addr,
+				    unsigned long size);
+
+#endif /* find_first_bit */
+
+#ifndef find_first_zero_bit
+
+/**
+ * find_first_zero_bit - find the first cleared bit in a memory region
+ * @addr: The address to start the search at
+ * @size: The maximum number of bits to search
+ *
+ * Returns the bit number of the first cleared bit.
+ * If no bits are zero, returns @size.
+ */
+unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size);
+#endif
+
+#endif /*_TOOLS_LINUX_ASM_GENERIC_BITOPS_FIND_H_ */
\ No newline at end of file
diff --git a/include/gcc_builtin.h b/include/gcc_builtin.h
new file mode 100644
index 0000000..366813b
--- /dev/null
+++ b/include/gcc_builtin.h
@@ -0,0 +1,118 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TOOLS_LINUX_COMPILER_H_
+#define _TOOLS_LINUX_COMPILER_H_
+
+#ifndef __compiletime_error
+# define __compiletime_error(message)
+#endif
+
+/* Optimization barrier */
+/* The "volatile" is due to gcc bugs */
+#define barrier() __asm__ __volatile__("": : :"memory")
+
+#ifndef __always_inline
+# define __always_inline	inline __attribute__((always_inline))
+#endif
+
+#ifndef noinline
+#define noinline
+#endif
+
+/* Are two types/vars the same type (ignoring qualifiers)? */
+#ifndef __same_type
+# define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
+#endif
+
+#ifdef __ANDROID__
+/*
+ * FIXME: Big hammer to get rid of tons of:
+ *   "warning: always_inline function might not be inlinable"
+ *
+ * At least on android-ndk-r12/platforms/android-24/arch-arm
+ */
+#undef __always_inline
+#define __always_inline	inline
+#endif
+
+#define __user
+#define __rcu
+#define __read_mostly
+
+#ifndef __attribute_const__
+# define __attribute_const__
+#endif
+
+#ifndef __maybe_unused
+# define __maybe_unused		__attribute__((unused))
+#endif
+
+#ifndef __used
+# define __used		__attribute__((__unused__))
+#endif
+
+#ifndef __packed
+# define __packed		__attribute__((__packed__))
+#endif
+
+#ifndef __force
+# define __force
+#endif
+
+#ifndef __weak
+# define __weak			__attribute__((weak))
+#endif
+
+#ifndef likely
+# define likely(x)		__builtin_expect(!!(x), 1)
+#endif
+
+#ifndef unlikely
+# define unlikely(x)		__builtin_expect(!!(x), 0)
+#endif
+
+#ifndef __init
+# define __init
+#endif
+
+#ifndef noinline
+# define noinline
+#endif
+
+#define uninitialized_var(x) x = *(&(x))
+
+#ifndef __fallthrough
+# define __fallthrough
+#endif
+
+#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
+
+#ifndef max
+#define max(x, y) ({				\
+	typeof(x) _max1 = (x);			\
+	typeof(y) _max2 = (y);			\
+	(void) (&_max1 == &_max2);		\
+	_max1 > _max2 ? _max1 : _max2; })
+#endif
+
+#ifndef min
+#define min(x, y) ({				\
+	typeof(x) _min1 = (x);			\
+	typeof(y) _min2 = (y);			\
+	(void) (&_min1 == &_min2);		\
+	_min1 < _min2 ? _min1 : _min2; })
+#endif
+
+#ifndef roundup
+#define roundup(x, y) (                                \
+{                                                      \
+	const typeof(y) __y = y;		       \
+	(((x) + (__y - 1)) / __y) * __y;	       \
+}                                                      \
+)
+#endif
+
+#define __round_mask(x, y) ((__typeof__(x))((y)-1))
+#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
+#define round_down(x, y) ((x) & ~__round_mask(x, y))
+
+#endif /* _TOOLS_LINUX_COMPILER_H */
\ No newline at end of file
diff --git a/include/hash.h b/include/hash.h
index 6d0b4ac..85ff038 100644
--- a/include/hash.h
+++ b/include/hash.h
@@ -1,6 +1,7 @@
 #ifndef _GENERIC_HASH_H
 #define _GENERIC_HASH_H
 
+#include "bitmap.h"
 #include "jhash.h"
 
 /* Fast hashing routine for ints,  longs and pointers.
@@ -113,6 +114,17 @@ int __ilog2_u64(uint64_t n)
 	__ilog2_u64(n)				\
  )
 
+
+#if BITS_PER_LONG == 32
+#define GOLDEN_RATIO_PRIME GOLDEN_RATIO_32
+#define hash_long(val, bits) hash_32(val, bits)
+#elif BITS_PER_LONG == 64
+#define hash_long(val, bits) hash_64(val, bits)
+#define GOLDEN_RATIO_PRIME GOLDEN_RATIO_64
+#else
+#error Wordsize not 32 or 64
+#endif
+
 /*
  * This hash multiplies the input by a large odd number and takes the
  * high bits.  Since multiplication propagates changes to the most
diff --git a/include/hashtable.h b/include/hashtable.h
index 068070f..2823192 100644
--- a/include/hashtable.h
+++ b/include/hashtable.h
@@ -9,7 +9,6 @@
 
 #include "list.h"
 #include "hash.h"
-#include "bitmap.h"
 
 #ifndef __same_type
 # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
@@ -149,5 +148,4 @@ static inline void hash_del(struct hlist_node *node)
 	hlist_for_each_entry_safe(obj, tmp,\
 		&name[hash_min(key, HASH_BITS(name))], member)
 
-
 #endif
\ No newline at end of file
diff --git a/include/jhash.h b/include/jhash.h
index bd03005..3dfcc6e 100644
--- a/include/jhash.h
+++ b/include/jhash.h
@@ -79,7 +79,7 @@ static inline uint32_t __get_unaligned_cpu32(const void *p)
 static inline uint32_t jhash(const void *key, uint32_t length, uint32_t initval)
 {
 	uint32_t a, b, c;
-	const uint8_t *k = key;
+	const uint8_t *k = (uint8_t *)key;
 
 	/* Set up the internal state */
 	a = b = c = JHASH_INITVAL + length + initval;
diff --git a/include/list.h b/include/list.h
index 4aa9a43..f122411 100644
--- a/include/list.h
+++ b/include/list.h
@@ -60,46 +60,46 @@ static inline void INIT_LIST_HEAD(struct list_head *list)
 }
 
 /*
- * Insert a new entry between two known consecutive entries.
+ * Insert a add entry between two known consecutive entries.
  *
  * This is only for internal list manipulation where we know
  * the prev/next entries already!
  */
-static inline void __list_add(struct list_head *new,
+static inline void __list_add(struct list_head *add,
 			      struct list_head *prev,
 			      struct list_head *next)
 {
-	next->prev = new;
-	new->next = next;
-	new->prev = prev;
-	prev->next = new;
+	next->prev = add;
+	add->next = next;
+	add->prev = prev;
+	prev->next = add;
 }
 
 /**
- * list_add - add a new entry
- * @new: new entry to be added
+ * list_add - add a add entry
+ * @add: add entry to be added
  * @head: list head to add it after
  *
- * Insert a new entry after the specified head.
+ * Insert a add entry after the specified head.
  * This is good for implementing stacks.
  */
-static inline void list_add(struct list_head *new, struct list_head *head)
+static inline void list_add(struct list_head *add, struct list_head *head)
 {
-	__list_add(new, head, head->next);
+	__list_add(add, head, head->next);
 }
 
 
 /**
- * list_add_tail - add a new entry
- * @new: new entry to be added
+ * list_add_tail - add a add entry
+ * @add: add entry to be added
  * @head: list head to add it before
  *
- * Insert a new entry before the specified head.
+ * Insert a add entry before the specified head.
  * This is useful for implementing queues.
  */
-static inline void list_add_tail(struct list_head *new, struct list_head *head)
+static inline void list_add_tail(struct list_head *add, struct list_head *head)
 {
-	__list_add(new, head->prev, head);
+	__list_add(add, head->prev, head);
 }
 
 /*
@@ -129,30 +129,30 @@ static inline void __list_del_entry(struct list_head *entry)
 static inline void list_del(struct list_head *entry)
 {
 	__list_del(entry->prev, entry->next);
-	entry->next = LIST_POISON1;
-	entry->prev = LIST_POISON2;
+	entry->next = (struct list_head *)LIST_POISON1;
+	entry->prev = (struct list_head *)LIST_POISON2;
 }
 
 /**
- * list_replace - replace old entry by new one
+ * list_replace - replace old entry by add one
  * @old : the element to be replaced
- * @new : the new element to insert
+ * @add : the add element to insert
  *
  * If @old was empty, it will be overwritten.
  */
 static inline void list_replace(struct list_head *old,
-				struct list_head *new)
+				struct list_head *add)
 {
-	new->next = old->next;
-	new->next->prev = new;
-	new->prev = old->prev;
-	new->prev->next = new;
+	add->next = old->next;
+	add->next->prev = add;
+	add->prev = old->prev;
+	add->prev->next = add;
 }
 
 static inline void list_replace_init(struct list_head *old,
-					struct list_head *new)
+					struct list_head *add)
 {
-	list_replace(old, new);
+	list_replace(old, add);
 	INIT_LIST_HEAD(old);
 }
 
@@ -265,7 +265,7 @@ static inline void __list_cut_position(struct list_head *list,
 
 /**
  * list_cut_position - cut a list into two
- * @list: a new list to add all removed entries
+ * @list: a add list to add all removed entries
  * @head: a list with entries
  * @entry: an entry within head, could be the head itself
  *	and if so we won't cut the list
@@ -307,7 +307,7 @@ static inline void __list_splice(const struct list_head *list,
 
 /**
  * list_splice - join two lists, this is designed for stacks
- * @list: the new list to add.
+ * @list: the add list to add.
  * @head: the place to add it in the first list.
  */
 static inline void list_splice(const struct list_head *list,
@@ -319,7 +319,7 @@ static inline void list_splice(const struct list_head *list,
 
 /**
  * list_splice_tail - join two lists, each list being a queue
- * @list: the new list to add.
+ * @list: the add list to add.
  * @head: the place to add it in the first list.
  */
 static inline void list_splice_tail(struct list_head *list,
@@ -331,7 +331,7 @@ static inline void list_splice_tail(struct list_head *list,
 
 /**
  * list_splice_init - join two lists and reinitialise the emptied list.
- * @list: the new list to add.
+ * @list: the add list to add.
  * @head: the place to add it in the first list.
  *
  * The list at @list is reinitialised
@@ -347,7 +347,7 @@ static inline void list_splice_init(struct list_head *list,
 
 /**
  * list_splice_tail_init - join two lists and reinitialise the emptied list
- * @list: the new list to add.
+ * @list: the add list to add.
  * @head: the place to add it in the first list.
  *
  * Each of the lists is a queue.
@@ -644,8 +644,8 @@ static inline void __hlist_del(struct hlist_node *n)
 static inline void hlist_del(struct hlist_node *n)
 {
 	__hlist_del(n);
-	n->next = LIST_POISON1;
-	n->pprev = LIST_POISON2;
+	n->next = (struct hlist_node *)LIST_POISON1;
+	n->pprev = (struct hlist_node **)LIST_POISON2;
 }
 
 static inline void hlist_del_init(struct hlist_node *n)
@@ -703,11 +703,11 @@ static inline bool hlist_fake(struct hlist_node *h)
  * reference of the first entry if it exists.
  */
 static inline void hlist_move_list(struct hlist_head *old,
-				   struct hlist_head *new)
+				   struct hlist_head *add)
 {
-	new->first = old->first;
-	if (new->first)
-		new->first->pprev = &new->first;
+	add->first = old->first;
+	if (add->first)
+		add->first->pprev = &add->first;
 	old->first = NULL;
 }
 
diff --git a/lib/bitops.c b/lib/bitops.c
new file mode 100644
index 0000000..bffefae
--- /dev/null
+++ b/lib/bitops.c
@@ -0,0 +1,154 @@
+
+#include "bitmap.h"
+#include "bitops.h"
+
+/*
+ * This is a common helper function for find_next_bit, find_next_zero_bit, and
+ * find_next_and_bit. The differences are:
+ *  - The "invert" argument, which is XORed with each fetched word before
+ *    searching it for one bits.
+ *  - The optional "addr2", which is anded with "addr1" if present.
+ */
+static inline unsigned long _find_next_bit(const unsigned long *addr1,
+		const unsigned long *addr2, unsigned long nbits,
+		unsigned long start, unsigned long invert)
+{
+	unsigned long tmp;
+
+	if (unlikely(start >= nbits))
+		return nbits;
+
+	tmp = addr1[start / BITS_PER_LONG];
+	if (addr2)
+		tmp &= addr2[start / BITS_PER_LONG];
+	tmp ^= invert;
+
+	/* Handle 1st word. */
+	tmp &= BITMAP_FIRST_WORD_MASK(start);
+	start = round_down(start, BITS_PER_LONG);
+
+	while (!tmp) {
+		start += BITS_PER_LONG;
+		if (start >= nbits)
+			return nbits;
+
+		tmp = addr1[start / BITS_PER_LONG];
+		if (addr2)
+			tmp &= addr2[start / BITS_PER_LONG];
+		tmp ^= invert;
+	}
+
+	return min(start + __ffs(tmp), nbits);
+}
+
+/*
+ * Find the next set bit in a memory region.
+ */
+unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
+			    unsigned long offset)
+{
+	return _find_next_bit(addr, NULL, size, offset, 0UL);
+}
+
+/*
+ * Find the first set bit in a memory region.
+ */
+unsigned long find_first_bit(const unsigned long *addr, unsigned long size)
+{
+	unsigned long idx;
+
+	for (idx = 0; idx * BITS_PER_LONG < size; idx++) {
+		if (addr[idx])
+			return min(idx * BITS_PER_LONG + __ffs(addr[idx]), size);
+	}
+
+	return size;
+}
+
+/*
+ * Find the first cleared bit in a memory region.
+ */
+unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size)
+{
+	unsigned long idx;
+
+	for (idx = 0; idx * BITS_PER_LONG < size; idx++) {
+		if (addr[idx] != ~0UL)
+			return min(idx * BITS_PER_LONG + ffz(addr[idx]), size);
+	}
+
+	return size;
+}
+
+unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
+				 unsigned long offset)
+{
+	return _find_next_bit(addr, NULL, size, offset, ~0UL);
+}
+
+unsigned long find_next_and_bit(const unsigned long *addr1,
+		const unsigned long *addr2, unsigned long size,
+		unsigned long offset)
+{
+	return _find_next_bit(addr1, addr2, size, offset, 0UL);
+}
+
+/**
+ * hweightN - returns the hamming weight of a N-bit word
+ * @x: the word to weigh
+ *
+ * The Hamming Weight of a number is the total number of bits set in it.
+ */
+
+unsigned int __sw_hweight32(unsigned int w)
+{
+#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
+	w -= (w >> 1) & 0x55555555;
+	w =  (w & 0x33333333) + ((w >> 2) & 0x33333333);
+	w =  (w + (w >> 4)) & 0x0f0f0f0f;
+	return (w * 0x01010101) >> 24;
+#else
+	unsigned int res = w - ((w >> 1) & 0x55555555);
+	res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
+	res = (res + (res >> 4)) & 0x0F0F0F0F;
+	res = res + (res >> 8);
+	return (res + (res >> 16)) & 0x000000FF;
+#endif
+}
+
+unsigned int __sw_hweight16(unsigned int w)
+{
+	unsigned int res = w - ((w >> 1) & 0x5555);
+	res = (res & 0x3333) + ((res >> 2) & 0x3333);
+	res = (res + (res >> 4)) & 0x0F0F;
+	return (res + (res >> 8)) & 0x00FF;
+}
+
+unsigned int __sw_hweight8(unsigned int w)
+{
+	unsigned int res = w - ((w >> 1) & 0x55);
+	res = (res & 0x33) + ((res >> 2) & 0x33);
+	return (res + (res >> 4)) & 0x0F;
+}
+
+unsigned long __sw_hweight64(uint64_t w)
+{
+#if BITS_PER_LONG == 32
+	return __sw_hweight32((unsigned int)(w >> 32)) +
+	       __sw_hweight32((unsigned int)w);
+#elif BITS_PER_LONG == 64
+#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
+	w -= (w >> 1) & 0x5555555555555555ul;
+	w =  (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul);
+	w =  (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful;
+	return (w * 0x0101010101010101ul) >> 56;
+#else
+	uint64_t res = w - ((w >> 1) & 0x5555555555555555ul);
+	res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
+	res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;
+	res = res + (res >> 8);
+	res = res + (res >> 16);
+	return (res + (res >> 32)) & 0x00000000000000FFul;
+#endif
+#endif
+}
\ No newline at end of file
diff --git a/smartdns.c b/smartdns.c
index 404acc8..9db5a02 100755
--- a/smartdns.c
+++ b/smartdns.c
@@ -1,132 +1,136 @@
+#include "fast_ping.h"
+#include "hashtable.h"
+#include "list.h"
 #include <stdio.h>
 #include <stdlib.h>
-#include "fast_ping.h"
-#include "list.h"
-#include "bitmap.h"
-#include "hashtable.h"
 
-void smartdns_ping_result(const char *host, int seqno, struct timeval *tv, void *userptr)
+void smartdns_ping_result(const char *host, FAST_PING_RESULT result, int seqno, struct timeval *tv, void *userptr)
 {
-	double rtt = tv->tv_sec * 1000.0 + tv->tv_usec / 1000.0;
-	printf("%16s: seq=%d time=%.3f\n", host, seqno, rtt);
+    if (result == PING_RESULT_RESPONSE) {
+        double rtt = tv->tv_sec * 1000.0 + tv->tv_usec / 1000.0;
+        printf("%16s: seq=%d time=%.3f\n", host, seqno, rtt);
+    } else if (result == PING_RESULT_TIMEOUT) {
+		printf("%16s: seq=%d timeout\n", host, seqno);
+    }
 }
 
 int smartdns_init()
 {
-	int ret;
+    int ret;
 
-	ret = fast_ping_init();
-	if (ret != 0) {
-		fprintf(stderr, "start ping failed.\n");
-		goto errout;
-	}
+    ret = fast_ping_init();
+    if (ret != 0) {
+        fprintf(stderr, "start ping failed.\n");
+        goto errout;
+    }
 
-	fast_ping_result_callback(smartdns_ping_result);
+    fast_ping_result_callback(smartdns_ping_result);
 
-	return 0;
+    return 0;
 errout:
 
-	return -1;
+    return -1;
 }
 
 int smartdns_run()
 {
-	sleep(1);
-	fast_ping_start("192.168.1.1", 2000, 0);
-	fast_ping_start("192.168.1.35", 2000, 0);
-	fast_ping_start("14.215.177.38", 2000, 0);
-	fast_ping_start("113.96.161.87", 2000, 0);
-	//fast_ping_start("::1", 2000, 0);
-	while (1) {
-		sleep(10);
-		//fast_ping_stop("192.168.1.35");
-	}
+    fast_ping_start("192.168.1.1", 2000, 0);
+    fast_ping_start("192.168.1.35", 2000, 0);
+    fast_ping_start("14.215.177.38", 2000, 0);
+    fast_ping_start("113.96.161.87", 2000, 0);
+    fast_ping_start("::1", 2000, 0);
+    fast_ping_start("12.4.3.1", 1000, 0);
+    while (1) {
+        sleep(10);
+        //fast_ping_stop("192.168.1.35");
+    }
 }
 
 void smartdns_exit()
 {
-	fast_ping_exit();
+    fast_ping_exit();
 }
 
 struct data {
-	struct list_head list;
-	int n;
+    struct list_head list;
+    int n;
 };
 
 void list_test()
 {
-	struct list_head head ;
-	struct list_head *iter;
-	int i = 0;
+    struct list_head head;
+    struct list_head *iter;
+    int i = 0;
 
-	INIT_LIST_HEAD(&head);
+    INIT_LIST_HEAD(&head);
 
-	for (i = 0; i < 10; i++) {
-		struct data *h = malloc(sizeof(struct data));
-		h->n = i;
-		list_add(&h->list, &head);
-	}
+    for (i = 0; i < 10; i++) {
+        struct data *h = malloc(sizeof(struct data));
+        h->n = i;
+        list_add(&h->list, &head);
+    }
 
-	list_for_each(iter, &head) {
-        struct data *d= list_entry(iter, struct data, list);
+    list_for_each(iter, &head)
+    {
+        struct data *d = list_entry(iter, struct data, list);
         printf("%d\n", d->n);
     }
 }
 
 struct data_hash {
-	struct hlist_node node;
-	int n;
-	char str[32];
+    struct hlist_node node;
+    int n;
+    char str[32];
 };
 
 int hash_test()
 {
-	DEFINE_HASHTABLE(ht, 7);
-	struct data_hash *temp;
-	struct data_hash *obj;
-	int i;
-	int j;
-	int key;
+    DEFINE_HASHTABLE(ht, 7);
+    struct data_hash *temp;
+    struct data_hash *obj;
+    int i;
+    int key;
 
-	for (i = 11; i < 17; i++) {
-		temp = malloc(sizeof(struct data_hash));
-		temp->n = i * i;
-		hash_add(ht, &temp->node, temp->n);
-	}
+    for (i = 11; i < 17; i++) {
+        temp = malloc(sizeof(struct data_hash));
+        temp->n = i * i;
+        hash_add(ht, &temp->node, temp->n);
+    }
 
-	for (i = 11; i < 17; i++) {
-		key = i * i;
-		hash_for_each_possible(ht, obj, node, key) {
-			printf("value: %d\n", obj->n);
-		};
-	}
+    for (i = 11; i < 17; i++) {
+        key = i * i;
+        hash_for_each_possible(ht, obj, node, key)
+        {
+            printf("value: %d\n", obj->n);
+        };
+    }
 
     return 0;
 }
 
 int hash_string_test()
 {
-	DEFINE_HASHTABLE(ht, 7);
-	struct data_hash *temp;
-	struct data_hash *obj;
-	int i;
-	int j;
-	int key;
+    DEFINE_HASHTABLE(ht, 7);
+    struct data_hash *temp;
+    struct data_hash *obj;
+    int i;
+    int key;
 
-	for (i = 0; i < 10; i++) {
-		temp = malloc(sizeof(struct data_hash));
-		sprintf(temp->str, "%d", i);
-		hash_add(ht, &temp->node, hash_string(temp->str));
-	}
+    for (i = 0; i < 10; i++) {
+        temp = malloc(sizeof(struct data_hash));
+        sprintf(temp->str, "%d", i);
+        hash_add(ht, &temp->node, hash_string(temp->str));
+    }
 
-	for (i = 0; i < 10; i++) {
-		char key_str[32];
-		sprintf(key_str, "%d", i);
-		key = hash_string(key_str);
-		hash_for_each_possible(ht, obj, node, key) {
-			printf("i = %d value: %s\n", i, obj->str);
-		};
-	}
+    for (i = 0; i < 10; i++) {
+        char key_str[32];
+        sprintf(key_str, "%d", i);
+        key = hash_string(key_str);
+        hash_for_each_possible(ht, obj, node, key)
+        {
+            printf("i = %d value: %s\n", i, obj->str);
+        };
+    }
 
     return 0;
 }
@@ -171,19 +175,19 @@ int rbtree_test()
 
 int main(int argc, char *argv[])
 {
-	int ret;
+    int ret;
 
-	atexit(smartdns_exit);
+    atexit(smartdns_exit);
 
-	ret = smartdns_init();
-	if (ret != 0) {
-		fprintf(stderr, "init smartdns failed.\n");
-		goto errout;
-	}
+    ret = smartdns_init();
+    if (ret != 0) {
+        fprintf(stderr, "init smartdns failed.\n");
+        goto errout;
+    }
 
-	return smartdns_run();
+    return smartdns_run();
 
 errout:
 
-	return 1;
+    return 1;
 }
\ No newline at end of file