diff --git a/daemon/common/city-hash.cpp b/daemon/common/city-hash.cpp
new file mode 100644
index 0000000..b8a7791
--- /dev/null
+++ b/daemon/common/city-hash.cpp
@@ -0,0 +1,650 @@
+// Copyright (c) 2011 Google, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+// CityHash, by Geoff Pike and Jyrki Alakuijala
+//
+// This file provides CityHash64() and related functions.
+//
+// It's probably possible to create even faster hash functions by
+// writing a program that systematically explores some of the space of
+// possible hash functions, by using SIMD instructions, or by
+// compromising on hash quality.
+
+//#include "config.h"
+#include "city-hash.hpp"
+#include <algorithm>
+#include <string.h>  // for memcpy and memset
+
+using namespace std;
+
+
+static uint64 UNALIGNED_LOAD64(const char *p) {
+  uint64 result;
+  memcpy(&result, p, sizeof(result));
+  return result;
+}
+
+static uint32 UNALIGNED_LOAD32(const char *p) {
+  uint32 result;
+  memcpy(&result, p, sizeof(result));
+  return result;
+}
+
+#ifdef _MSC_VER
+
+#include <stdlib.h>
+#define bswap_32(x) _byteswap_ulong(x)
+#define bswap_64(x) _byteswap_uint64(x)
+
+#elif defined(__APPLE__)
+
+// Mac OS X / Darwin features
+#include <libkern/OSByteOrder.h>
+#define bswap_32(x) OSSwapInt32(x)
+#define bswap_64(x) OSSwapInt64(x)
+
+#elif defined(__NetBSD__)
+
+#include <sys/types.h>
+#include <machine/bswap.h>
+#if defined(__BSWAP_RENAME) && !defined(__bswap_32)
+#define bswap_32(x) bswap32(x)
+#define bswap_64(x) bswap64(x)
+#endif
+
+
+#elif defined(__FreeBSD__)
+
+// Based on https://code.google.com/p/freebsd/source/browse/sys/ofed/include/byteswap.h?spec=svn38a8350a629d959c8c5509221cd07ffb891b5a77&r=38a8350a629d959c8c5509221cd07ffb891b5a77
+
+#include <sys/types.h>
+#include <sys/endian.h>
+#define bswap_16(x) bswap16(x)
+#define bswap_32(x) bswap32(x)
+#define bswap_64(x) bswap64(x)
+
+#else
+
+#include <byteswap.h>
+
+#endif
+
+#ifdef WORDS_BIGENDIAN
+#define uint32_in_expected_order(x) (bswap_32(x))
+#define uint64_in_expected_order(x) (bswap_64(x))
+#else
+#define uint32_in_expected_order(x) (x)
+#define uint64_in_expected_order(x) (x)
+#endif
+
+#if !defined(LIKELY)
+#if HAVE_BUILTIN_EXPECT
+#define LIKELY(x) (__builtin_expect(!!(x), 1))
+#else
+#define LIKELY(x) (x)
+#endif
+#endif
+
+static uint64 Fetch64(const char *p) {
+  return uint64_in_expected_order(UNALIGNED_LOAD64(p));
+}
+
+static uint32 Fetch32(const char *p) {
+  return uint32_in_expected_order(UNALIGNED_LOAD32(p));
+}
+
+// Some primes between 2^63 and 2^64 for various uses.
+static const uint64 k0 = 0xc3a5c85c97cb3127ULL;
+static const uint64 k1 = 0xb492b66fbe98f273ULL;
+static const uint64 k2 = 0x9ae16a3b2f90404fULL;
+
+// Magic numbers for 32-bit hashing.  Copied from Murmur3.
+static const uint32_t c1 = 0xcc9e2d51;
+static const uint32_t c2 = 0x1b873593;
+
+// A 32-bit to 32-bit integer hash copied from Murmur3.
+static uint32 fmix(uint32 h)
+{
+  h ^= h >> 16;
+  h *= 0x85ebca6b;
+  h ^= h >> 13;
+  h *= 0xc2b2ae35;
+  h ^= h >> 16;
+  return h;
+}
+
+static uint32 Rotate32(uint32 val, int shift) {
+  // Avoid shifting by 32: doing so yields an undefined result.
+  return shift == 0 ? val : ((val >> shift) | (val << (32 - shift)));
+}
+
+#undef PERMUTE3
+#define PERMUTE3(a, b, c) do { std::swap(a, b); std::swap(a, c); } while (0)
+
+static uint32 Mur(uint32 a, uint32 h) {
+  // Helper from Murmur3 for combining two 32-bit values.
+  a *= c1;
+  a = Rotate32(a, 17);
+  a *= c2;
+  h ^= a;
+  h = Rotate32(h, 19);
+  return h * 5 + 0xe6546b64;
+}
+
+static uint32 Hash32Len13to24(const char *s, size_t len) {
+  uint32 a = Fetch32(s - 4 + (len >> 1));
+  uint32 b = Fetch32(s + 4);
+  uint32 c = Fetch32(s + len - 8);
+  uint32 d = Fetch32(s + (len >> 1));
+  uint32 e = Fetch32(s);
+  uint32 f = Fetch32(s + len - 4);
+  uint32 h = len;
+
+  return fmix(Mur(f, Mur(e, Mur(d, Mur(c, Mur(b, Mur(a, h)))))));
+}
+
+static uint32 Hash32Len0to4(const char *s, size_t len) {
+  uint32 b = 0;
+  uint32 c = 9;
+  for (size_t i = 0; i < len; i++) {
+    signed char v = s[i];
+    b = b * c1 + v;
+    c ^= b;
+  }
+  return fmix(Mur(b, Mur(len, c)));
+}
+
+static uint32 Hash32Len5to12(const char *s, size_t len) {
+  uint32 a = len, b = len * 5, c = 9, d = b;
+  a += Fetch32(s);
+  b += Fetch32(s + len - 4);
+  c += Fetch32(s + ((len >> 1) & 4));
+  return fmix(Mur(c, Mur(b, Mur(a, d))));
+}
+
+uint32 CityHash32(const char *s, size_t len) {
+  if (len <= 24) {
+    return len <= 12 ?
+        (len <= 4 ? Hash32Len0to4(s, len) : Hash32Len5to12(s, len)) :
+        Hash32Len13to24(s, len);
+  }
+
+  // len > 24
+  uint32 h = len, g = c1 * len, f = g;
+  uint32 a0 = Rotate32(Fetch32(s + len - 4) * c1, 17) * c2;
+  uint32 a1 = Rotate32(Fetch32(s + len - 8) * c1, 17) * c2;
+  uint32 a2 = Rotate32(Fetch32(s + len - 16) * c1, 17) * c2;
+  uint32 a3 = Rotate32(Fetch32(s + len - 12) * c1, 17) * c2;
+  uint32 a4 = Rotate32(Fetch32(s + len - 20) * c1, 17) * c2;
+  h ^= a0;
+  h = Rotate32(h, 19);
+  h = h * 5 + 0xe6546b64;
+  h ^= a2;
+  h = Rotate32(h, 19);
+  h = h * 5 + 0xe6546b64;
+  g ^= a1;
+  g = Rotate32(g, 19);
+  g = g * 5 + 0xe6546b64;
+  g ^= a3;
+  g = Rotate32(g, 19);
+  g = g * 5 + 0xe6546b64;
+  f += a4;
+  f = Rotate32(f, 19);
+  f = f * 5 + 0xe6546b64;
+  size_t iters = (len - 1) / 20;
+  do {
+    uint32 a0 = Rotate32(Fetch32(s) * c1, 17) * c2;
+    uint32 a1 = Fetch32(s + 4);
+    uint32 a2 = Rotate32(Fetch32(s + 8) * c1, 17) * c2;
+    uint32 a3 = Rotate32(Fetch32(s + 12) * c1, 17) * c2;
+    uint32 a4 = Fetch32(s + 16);
+    h ^= a0;
+    h = Rotate32(h, 18);
+    h = h * 5 + 0xe6546b64;
+    f += a1;
+    f = Rotate32(f, 19);
+    f = f * c1;
+    g += a2;
+    g = Rotate32(g, 18);
+    g = g * 5 + 0xe6546b64;
+    h ^= a3 + a1;
+    h = Rotate32(h, 19);
+    h = h * 5 + 0xe6546b64;
+    g ^= a4;
+    g = bswap_32(g) * 5;
+    h += a4 * 5;
+    h = bswap_32(h);
+    f += a0;
+    PERMUTE3(f, h, g);
+    s += 20;
+  } while (--iters != 0);
+  g = Rotate32(g, 11) * c1;
+  g = Rotate32(g, 17) * c1;
+  f = Rotate32(f, 11) * c1;
+  f = Rotate32(f, 17) * c1;
+  h = Rotate32(h + g, 19);
+  h = h * 5 + 0xe6546b64;
+  h = Rotate32(h, 17) * c1;
+  h = Rotate32(h + f, 19);
+  h = h * 5 + 0xe6546b64;
+  h = Rotate32(h, 17) * c1;
+  return h;
+}
+
+// Bitwise right rotate.  Normally this will compile to a single
+// instruction, especially if the shift is a manifest constant.
+static uint64 Rotate(uint64 val, int shift) {
+  // Avoid shifting by 64: doing so yields an undefined result.
+  return shift == 0 ? val : ((val >> shift) | (val << (64 - shift)));
+}
+
+static uint64 ShiftMix(uint64 val) {
+  return val ^ (val >> 47);
+}
+
+static uint64 HashLen16(uint64 u, uint64 v) {
+  return Hash128to64(uint128(u, v));
+}
+
+static uint64 HashLen16(uint64 u, uint64 v, uint64 mul) {
+  // Murmur-inspired hashing.
+  uint64 a = (u ^ v) * mul;
+  a ^= (a >> 47);
+  uint64 b = (v ^ a) * mul;
+  b ^= (b >> 47);
+  b *= mul;
+  return b;
+}
+
+static uint64 HashLen0to16(const char *s, size_t len) {
+  if (len >= 8) {
+    uint64 mul = k2 + len * 2;
+    uint64 a = Fetch64(s) + k2;
+    uint64 b = Fetch64(s + len - 8);
+    uint64 c = Rotate(b, 37) * mul + a;
+    uint64 d = (Rotate(a, 25) + b) * mul;
+    return HashLen16(c, d, mul);
+  }
+  if (len >= 4) {
+    uint64 mul = k2 + len * 2;
+    uint64 a = Fetch32(s);
+    return HashLen16(len + (a << 3), Fetch32(s + len - 4), mul);
+  }
+  if (len > 0) {
+    uint8 a = s[0];
+    uint8 b = s[len >> 1];
+    uint8 c = s[len - 1];
+    uint32 y = static_cast<uint32>(a) + (static_cast<uint32>(b) << 8);
+    uint32 z = len + (static_cast<uint32>(c) << 2);
+    return ShiftMix(y * k2 ^ z * k0) * k2;
+  }
+  return k2;
+}
+
+// This probably works well for 16-byte strings as well, but it may be overkill
+// in that case.
+static uint64 HashLen17to32(const char *s, size_t len) {
+  uint64 mul = k2 + len * 2;
+  uint64 a = Fetch64(s) * k1;
+  uint64 b = Fetch64(s + 8);
+  uint64 c = Fetch64(s + len - 8) * mul;
+  uint64 d = Fetch64(s + len - 16) * k2;
+  return HashLen16(Rotate(a + b, 43) + Rotate(c, 30) + d,
+                   a + Rotate(b + k2, 18) + c, mul);
+}
+
+// Return a 16-byte hash for 48 bytes.  Quick and dirty.
+// Callers do best to use "random-looking" values for a and b.
+static pair<uint64, uint64> WeakHashLen32WithSeeds(
+    uint64 w, uint64 x, uint64 y, uint64 z, uint64 a, uint64 b) {
+  a += w;
+  b = Rotate(b + a + z, 21);
+  uint64 c = a;
+  a += x;
+  a += y;
+  b += Rotate(a, 44);
+  return make_pair(a + z, b + c);
+}
+
+// Return a 16-byte hash for s[0] ... s[31], a, and b.  Quick and dirty.
+static pair<uint64, uint64> WeakHashLen32WithSeeds(
+    const char* s, uint64 a, uint64 b) {
+  return WeakHashLen32WithSeeds(Fetch64(s),
+                                Fetch64(s + 8),
+                                Fetch64(s + 16),
+                                Fetch64(s + 24),
+                                a,
+                                b);
+}
+
+// Return an 8-byte hash for 33 to 64 bytes.
+static uint64 HashLen33to64(const char *s, size_t len) {
+  uint64 mul = k2 + len * 2;
+  uint64 a = Fetch64(s) * k2;
+  uint64 b = Fetch64(s + 8);
+  uint64 c = Fetch64(s + len - 24);
+  uint64 d = Fetch64(s + len - 32);
+  uint64 e = Fetch64(s + 16) * k2;
+  uint64 f = Fetch64(s + 24) * 9;
+  uint64 g = Fetch64(s + len - 8);
+  uint64 h = Fetch64(s + len - 16) * mul;
+  uint64 u = Rotate(a + g, 43) + (Rotate(b, 30) + c) * 9;
+  uint64 v = ((a + g) ^ d) + f + 1;
+  uint64 w = bswap_64((u + v) * mul) + h;
+  uint64 x = Rotate(e + f, 42) + c;
+  uint64 y = (bswap_64((v + w) * mul) + g) * mul;
+  uint64 z = e + f + c;
+  a = bswap_64((x + z) * mul + y) + b;
+  b = ShiftMix((z + a) * mul + d + h) * mul;
+  return b + x;
+}
+
+uint64 CityHash64(const char *s, size_t len) {
+  if (len <= 32) {
+    if (len <= 16) {
+      return HashLen0to16(s, len);
+    } else {
+      return HashLen17to32(s, len);
+    }
+  } else if (len <= 64) {
+    return HashLen33to64(s, len);
+  }
+
+  // For strings over 64 bytes we hash the end first, and then as we
+  // loop we keep 56 bytes of state: v, w, x, y, and z.
+  uint64 x = Fetch64(s + len - 40);
+  uint64 y = Fetch64(s + len - 16) + Fetch64(s + len - 56);
+  uint64 z = HashLen16(Fetch64(s + len - 48) + len, Fetch64(s + len - 24));
+  pair<uint64, uint64> v = WeakHashLen32WithSeeds(s + len - 64, len, z);
+  pair<uint64, uint64> w = WeakHashLen32WithSeeds(s + len - 32, y + k1, x);
+  x = x * k1 + Fetch64(s);
+
+  // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
+  len = (len - 1) & ~static_cast<size_t>(63);
+  do {
+    x = Rotate(x + y + v.first + Fetch64(s + 8), 37) * k1;
+    y = Rotate(y + v.second + Fetch64(s + 48), 42) * k1;
+    x ^= w.second;
+    y += v.first + Fetch64(s + 40);
+    z = Rotate(z + w.first, 33) * k1;
+    v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first);
+    w = WeakHashLen32WithSeeds(s + 32, z + w.second, y + Fetch64(s + 16));
+    std::swap(z, x);
+    s += 64;
+    len -= 64;
+  } while (len != 0);
+  return HashLen16(HashLen16(v.first, w.first) + ShiftMix(y) * k1 + z,
+                   HashLen16(v.second, w.second) + x);
+}
+
+uint64 CityHash64WithSeed(const char *s, size_t len, uint64 seed) {
+  return CityHash64WithSeeds(s, len, k2, seed);
+}
+
+uint64 CityHash64WithSeeds(const char *s, size_t len,
+                           uint64 seed0, uint64 seed1) {
+  return HashLen16(CityHash64(s, len) - seed0, seed1);
+}
+
+// A subroutine for CityHash128().  Returns a decent 128-bit hash for strings
+// of any length representable in signed long.  Based on City and Murmur.
+static uint128 CityMurmur(const char *s, size_t len, uint128 seed) {
+  uint64 a = Uint128Low64(seed);
+  uint64 b = Uint128High64(seed);
+  uint64 c = 0;
+  uint64 d = 0;
+  signed long l = len - 16;
+  if (l <= 0) {  // len <= 16
+    a = ShiftMix(a * k1) * k1;
+    c = b * k1 + HashLen0to16(s, len);
+    d = ShiftMix(a + (len >= 8 ? Fetch64(s) : c));
+  } else {  // len > 16
+    c = HashLen16(Fetch64(s + len - 8) + k1, a);
+    d = HashLen16(b + len, c + Fetch64(s + len - 16));
+    a += d;
+    do {
+      a ^= ShiftMix(Fetch64(s) * k1) * k1;
+      a *= k1;
+      b ^= a;
+      c ^= ShiftMix(Fetch64(s + 8) * k1) * k1;
+      c *= k1;
+      d ^= c;
+      s += 16;
+      l -= 16;
+    } while (l > 0);
+  }
+  a = HashLen16(a, c);
+  b = HashLen16(d, b);
+  return uint128(a ^ b, HashLen16(b, a));
+}
+
+uint128 CityHash128WithSeed(const char *s, size_t len, uint128 seed) {
+  if (len < 128) {
+    return CityMurmur(s, len, seed);
+  }
+
+  // We expect len >= 128 to be the common case.  Keep 56 bytes of state:
+  // v, w, x, y, and z.
+  pair<uint64, uint64> v, w;
+  uint64 x = Uint128Low64(seed);
+  uint64 y = Uint128High64(seed);
+  uint64 z = len * k1;
+  v.first = Rotate(y ^ k1, 49) * k1 + Fetch64(s);
+  v.second = Rotate(v.first, 42) * k1 + Fetch64(s + 8);
+  w.first = Rotate(y + z, 35) * k1 + x;
+  w.second = Rotate(x + Fetch64(s + 88), 53) * k1;
+
+  // This is the same inner loop as CityHash64(), manually unrolled.
+  do {
+    x = Rotate(x + y + v.first + Fetch64(s + 8), 37) * k1;
+    y = Rotate(y + v.second + Fetch64(s + 48), 42) * k1;
+    x ^= w.second;
+    y += v.first + Fetch64(s + 40);
+    z = Rotate(z + w.first, 33) * k1;
+    v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first);
+    w = WeakHashLen32WithSeeds(s + 32, z + w.second, y + Fetch64(s + 16));
+    std::swap(z, x);
+    s += 64;
+    x = Rotate(x + y + v.first + Fetch64(s + 8), 37) * k1;
+    y = Rotate(y + v.second + Fetch64(s + 48), 42) * k1;
+    x ^= w.second;
+    y += v.first + Fetch64(s + 40);
+    z = Rotate(z + w.first, 33) * k1;
+    v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first);
+    w = WeakHashLen32WithSeeds(s + 32, z + w.second, y + Fetch64(s + 16));
+    std::swap(z, x);
+    s += 64;
+    len -= 128;
+  } while (LIKELY(len >= 128));
+  x += Rotate(v.first + z, 49) * k0;
+  y = y * k0 + Rotate(w.second, 37);
+  z = z * k0 + Rotate(w.first, 27);
+  w.first *= 9;
+  v.first *= k0;
+  // If 0 < len < 128, hash up to 4 chunks of 32 bytes each from the end of s.
+  for (size_t tail_done = 0; tail_done < len; ) {
+    tail_done += 32;
+    y = Rotate(x + y, 42) * k0 + v.second;
+    w.first += Fetch64(s + len - tail_done + 16);
+    x = x * k0 + w.first;
+    z += w.second + Fetch64(s + len - tail_done);
+    w.second += v.first;
+    v = WeakHashLen32WithSeeds(s + len - tail_done, v.first + z, v.second);
+    v.first *= k0;
+  }
+  // At this point our 56 bytes of state should contain more than
+  // enough information for a strong 128-bit hash.  We use two
+  // different 56-byte-to-8-byte hashes to get a 16-byte final result.
+  x = HashLen16(x, v.first);
+  y = HashLen16(y + z, w.first);
+  return uint128(HashLen16(x + v.second, w.second) + y,
+                 HashLen16(x + w.second, y + v.second));
+}
+
+uint128 CityHash128(const char *s, size_t len) {
+  return len >= 16 ?
+      CityHash128WithSeed(s + 16, len - 16,
+                          uint128(Fetch64(s), Fetch64(s + 8) + k0)) :
+      CityHash128WithSeed(s, len, uint128(k0, k1));
+}
+
+// NFD NOTE
+// The following code block is commented out due to the following reasons.
+// - It requires the "citycrc.h" header file, which is not included in the
+//   NFD code base.
+// - The functions defined below are not used by the current NFD
+//   implementation.
+// The header file "citycrc.h" is available at
+// https://code.google.com/p/cityhash/source/browse/trunk/src/citycrc.h
+
+/*
+#ifdef __SSE4_2__
+#include <citycrc.h>
+#include <nmmintrin.h>
+
+// Requires len >= 240.
+static void CityHashCrc256Long(const char *s, size_t len,
+                               uint32 seed, uint64 *result) {
+  uint64 a = Fetch64(s + 56) + k0;
+  uint64 b = Fetch64(s + 96) + k0;
+  uint64 c = result[0] = HashLen16(b, len);
+  uint64 d = result[1] = Fetch64(s + 120) * k0 + len;
+  uint64 e = Fetch64(s + 184) + seed;
+  uint64 f = 0;
+  uint64 g = 0;
+  uint64 h = c + d;
+  uint64 x = seed;
+  uint64 y = 0;
+  uint64 z = 0;
+
+  // 240 bytes of input per iter.
+  size_t iters = len / 240;
+  len -= iters * 240;
+  do {
+#undef CHUNK
+#define CHUNK(r)                                \
+    PERMUTE3(x, z, y);                          \
+    b += Fetch64(s);                            \
+    c += Fetch64(s + 8);                        \
+    d += Fetch64(s + 16);                       \
+    e += Fetch64(s + 24);                       \
+    f += Fetch64(s + 32);                       \
+    a += b;                                     \
+    h += f;                                     \
+    b += c;                                     \
+    f += d;                                     \
+    g += e;                                     \
+    e += z;                                     \
+    g += x;                                     \
+    z = _mm_crc32_u64(z, b + g);                \
+    y = _mm_crc32_u64(y, e + h);                \
+    x = _mm_crc32_u64(x, f + a);                \
+    e = Rotate(e, r);                           \
+    c += e;                                     \
+    s += 40
+
+    CHUNK(0); PERMUTE3(a, h, c);
+    CHUNK(33); PERMUTE3(a, h, f);
+    CHUNK(0); PERMUTE3(b, h, f);
+    CHUNK(42); PERMUTE3(b, h, d);
+    CHUNK(0); PERMUTE3(b, h, e);
+    CHUNK(33); PERMUTE3(a, h, e);
+  } while (--iters > 0);
+
+  while (len >= 40) {
+    CHUNK(29);
+    e ^= Rotate(a, 20);
+    h += Rotate(b, 30);
+    g ^= Rotate(c, 40);
+    f += Rotate(d, 34);
+    PERMUTE3(c, h, g);
+    len -= 40;
+  }
+  if (len > 0) {
+    s = s + len - 40;
+    CHUNK(33);
+    e ^= Rotate(a, 43);
+    h += Rotate(b, 42);
+    g ^= Rotate(c, 41);
+    f += Rotate(d, 40);
+  }
+  result[0] ^= h;
+  result[1] ^= g;
+  g += h;
+  a = HashLen16(a, g + z);
+  x += y << 32;
+  b += x;
+  c = HashLen16(c, z) + h;
+  d = HashLen16(d, e + result[0]);
+  g += e;
+  h += HashLen16(x, f);
+  e = HashLen16(a, d) + g;
+  z = HashLen16(b, c) + a;
+  y = HashLen16(g, h) + c;
+  result[0] = e + z + y + x;
+  a = ShiftMix((a + y) * k0) * k0 + b;
+  result[1] += a + result[0];
+  a = ShiftMix(a * k0) * k0 + c;
+  result[2] = a + result[1];
+  a = ShiftMix((a + e) * k0) * k0;
+  result[3] = a + result[2];
+}
+
+// Requires len < 240.
+static void CityHashCrc256Short(const char *s, size_t len, uint64 *result) {
+  char buf[240];
+  memcpy(buf, s, len);
+  memset(buf + len, 0, 240 - len);
+  CityHashCrc256Long(buf, 240, ~static_cast<uint32>(len), result);
+}
+
+void CityHashCrc256(const char *s, size_t len, uint64 *result) {
+  if (LIKELY(len >= 240)) {
+    CityHashCrc256Long(s, len, 0, result);
+  } else {
+    CityHashCrc256Short(s, len, result);
+  }
+}
+
+uint128 CityHashCrc128WithSeed(const char *s, size_t len, uint128 seed) {
+  if (len <= 900) {
+    return CityHash128WithSeed(s, len, seed);
+  } else {
+    uint64 result[4];
+    CityHashCrc256(s, len, result);
+    uint64 u = Uint128High64(seed) + result[0];
+    uint64 v = Uint128Low64(seed) + result[1];
+    return uint128(HashLen16(u, v + result[2]),
+                   HashLen16(Rotate(v, 32), u * k0 + result[3]));
+  }
+}
+
+uint128 CityHashCrc128(const char *s, size_t len) {
+  if (len <= 900) {
+    return CityHash128(s, len);
+  } else {
+    uint64 result[4];
+    CityHashCrc256(s, len, result);
+    return uint128(result[2], result[3]);
+  }
+}
+
+#endif
+*/
diff --git a/daemon/common/city-hash.hpp b/daemon/common/city-hash.hpp
new file mode 100644
index 0000000..54a90cb
--- /dev/null
+++ b/daemon/common/city-hash.hpp
@@ -0,0 +1,112 @@
+// Copyright (c) 2011 Google, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+// CityHash, by Geoff Pike and Jyrki Alakuijala
+//
+// http://code.google.com/p/cityhash/
+//
+// This file provides a few functions for hashing strings.  All of them are
+// high-quality functions in the sense that they pass standard tests such
+// as Austin Appleby's SMHasher.  They are also fast.
+//
+// For 64-bit x86 code, on short strings, we don't know of anything faster than
+// CityHash64 that is of comparable quality.  We believe our nearest competitor
+// is Murmur3.  For 64-bit x86 code, CityHash64 is an excellent choice for hash
+// tables and most other hashing (excluding cryptography).
+//
+// For 64-bit x86 code, on long strings, the picture is more complicated.
+// On many recent Intel CPUs, such as Nehalem, Westmere, Sandy Bridge, etc.,
+// CityHashCrc128 appears to be faster than all competitors of comparable
+// quality.  CityHash128 is also good but not quite as fast.  We believe our
+// nearest competitor is Bob Jenkins' Spooky.  We don't have great data for
+// other 64-bit CPUs, but for long strings we know that Spooky is slightly
+// faster than CityHash on some relatively recent AMD x86-64 CPUs, for example.
+// Note that CityHashCrc128 is declared in citycrc.h.
+//
+// For 32-bit x86 code, we don't know of anything faster than CityHash32 that
+// is of comparable quality.  We believe our nearest competitor is Murmur3A.
+// (On 64-bit CPUs, it is typically faster to use the other CityHash variants.)
+//
+// Functions in the CityHash family are not suitable for cryptography.
+//
+// Please see CityHash's README file for more details on our performance
+// measurements and so on.
+//
+// WARNING: This code has been only lightly tested on big-endian platforms!
+// It is known to work well on little-endian platforms that have a small penalty
+// for unaligned reads, such as current Intel and AMD moderate-to-high-end CPUs.
+// It should work on all 32-bit and 64-bit platforms that allow unaligned reads;
+// bug reports are welcome.
+//
+// By the way, for some hash functions, given strings a and b, the hash
+// of a+b is easily derived from the hashes of a and b.  This property
+// doesn't hold for any hash functions in this file.
+
+#ifndef CITY_HASH_HPP
+#define CITY_HASH_HPP
+
+#include <stdlib.h>  // for size_t.
+#include <stdint.h>
+#include <utility>
+
+typedef uint8_t uint8;
+typedef uint32_t uint32;
+typedef uint64_t uint64;
+typedef std::pair<uint64, uint64> uint128;
+
+inline uint64 Uint128Low64(const uint128& x) { return x.first; }
+inline uint64 Uint128High64(const uint128& x) { return x.second; }
+
+// Hash function for a byte array.
+uint64 CityHash64(const char *buf, size_t len);
+
+// Hash function for a byte array.  For convenience, a 64-bit seed is also
+// hashed into the result.
+uint64 CityHash64WithSeed(const char *buf, size_t len, uint64 seed);
+
+// Hash function for a byte array.  For convenience, two seeds are also
+// hashed into the result.
+uint64 CityHash64WithSeeds(const char *buf, size_t len,
+                           uint64 seed0, uint64 seed1);
+
+// Hash function for a byte array.
+uint128 CityHash128(const char *s, size_t len);
+
+// Hash function for a byte array.  For convenience, a 128-bit seed is also
+// hashed into the result.
+uint128 CityHash128WithSeed(const char *s, size_t len, uint128 seed);
+
+// Hash function for a byte array.  Most useful in 32-bit binaries.
+uint32 CityHash32(const char *buf, size_t len);
+
+// Hash 128 input bits down to 64 bits of output.
+// This is intended to be a reasonably good hash function.
+inline uint64 Hash128to64(const uint128& x) {
+  // Murmur-inspired hashing.
+  const uint64 kMul = 0x9ddfea08eb382d69ULL;
+  uint64 a = (Uint128Low64(x) ^ Uint128High64(x)) * kMul;
+  a ^= (a >> 47);
+  uint64 b = (Uint128High64(x) ^ a) * kMul;
+  b ^= (b >> 47);
+  b *= kMul;
+  return b;
+}
+
+#endif  // CITY_HASH_H_
diff --git a/daemon/common/config-file.cpp b/daemon/common/config-file.cpp
new file mode 100644
index 0000000..8d70349
--- /dev/null
+++ b/daemon/common/config-file.cpp
@@ -0,0 +1,138 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2019,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "common/config-file.hpp"
+
+#include <boost/property_tree/info_parser.hpp>
+
+#include <fstream>
+#include <sstream>
+
+namespace nfd {
+
+ConfigFile::ConfigFile(UnknownConfigSectionHandler unknownSectionCallback)
+  : m_unknownSectionCallback(unknownSectionCallback)
+{
+}
+
+void
+ConfigFile::throwErrorOnUnknownSection(const std::string& filename,
+                                       const std::string& sectionName,
+                                       const ConfigSection& section,
+                                       bool isDryRun)
+{
+  NDN_THROW(Error("Error processing configuration file " + filename +
+                  ": no module subscribed for section '" + sectionName + "'"));
+}
+
+void
+ConfigFile::ignoreUnknownSection(const std::string& filename,
+                                 const std::string& sectionName,
+                                 const ConfigSection& section,
+                                 bool isDryRun)
+{
+  // do nothing
+}
+
+bool
+ConfigFile::parseYesNo(const ConfigSection& node, const std::string& key,
+                       const std::string& sectionName)
+{
+  auto value = node.get_value<std::string>();
+
+  if (value == "yes") {
+    return true;
+  }
+  else if (value == "no") {
+    return false;
+  }
+
+  NDN_THROW(Error("Invalid value '" + value + "' for option '" +
+                  key + "' in section '" + sectionName + "'"));
+}
+
+void
+ConfigFile::addSectionHandler(const std::string& sectionName,
+                              ConfigSectionHandler subscriber)
+{
+  m_subscriptions[sectionName] = subscriber;
+}
+
+void
+ConfigFile::parse(const std::string& filename, bool isDryRun)
+{
+  std::ifstream inputFile(filename);
+  if (!inputFile.good() || !inputFile.is_open()) {
+    NDN_THROW(Error("Failed to read configuration file " + filename));
+  }
+  parse(inputFile, isDryRun, filename);
+  inputFile.close();
+}
+
+void
+ConfigFile::parse(const std::string& input, bool isDryRun, const std::string& filename)
+{
+  std::istringstream inputStream(input);
+  parse(inputStream, isDryRun, filename);
+}
+
+void
+ConfigFile::parse(std::istream& input, bool isDryRun, const std::string& filename)
+{
+  try {
+    boost::property_tree::read_info(input, m_global);
+  }
+  catch (const boost::property_tree::info_parser_error& error) {
+    NDN_THROW(Error("Failed to parse configuration file " + filename +
+                    ": " + error.message() + " on line " + to_string(error.line())));
+  }
+
+  process(isDryRun, filename);
+}
+
+void
+ConfigFile::parse(const ConfigSection& config, bool isDryRun, const std::string& filename)
+{
+  m_global = config;
+  process(isDryRun, filename);
+}
+
+void
+ConfigFile::process(bool isDryRun, const std::string& filename) const
+{
+  BOOST_ASSERT(!filename.empty());
+
+  for (const auto& i : m_global) {
+    try {
+      const ConfigSectionHandler& subscriber = m_subscriptions.at(i.first);
+      subscriber(i.second, isDryRun, filename);
+    }
+    catch (const std::out_of_range&) {
+      m_unknownSectionCallback(filename, i.first, i.second, isDryRun);
+    }
+  }
+}
+
+} // namespace nfd
diff --git a/daemon/common/config-file.hpp b/daemon/common/config-file.hpp
new file mode 100644
index 0000000..20e778b
--- /dev/null
+++ b/daemon/common/config-file.hpp
@@ -0,0 +1,180 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2019,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef NFD_DAEMON_COMMON_CONFIG_FILE_HPP
+#define NFD_DAEMON_COMMON_CONFIG_FILE_HPP
+
+#include "core/common.hpp"
+
+#include <boost/property_tree/ptree.hpp>
+
+namespace nfd {
+
+/** \brief a config file section
+ */
+using ConfigSection = boost::property_tree::ptree;
+
+/** \brief an optional config file section
+ */
+using OptionalConfigSection = boost::optional<const ConfigSection&>;
+
+/** \brief callback to process a config file section
+ */
+using ConfigSectionHandler = std::function<void(const ConfigSection& section, bool isDryRun,
+                                                const std::string& filename)>;
+
+/** \brief callback to process a config file section without a \p ConfigSectionHandler
+ */
+using UnknownConfigSectionHandler = std::function<void(const std::string& filename,
+                                                       const std::string& sectionName,
+                                                       const ConfigSection& section,
+                                                       bool isDryRun)>;
+
+/** \brief configuration file parsing utility
+ */
+class ConfigFile : noncopyable
+{
+public:
+  class Error : public std::runtime_error
+  {
+  public:
+    using std::runtime_error::runtime_error;
+  };
+
+  explicit
+  ConfigFile(UnknownConfigSectionHandler unknownSectionCallback = throwErrorOnUnknownSection);
+
+public: // unknown section handlers
+  static void
+  throwErrorOnUnknownSection(const std::string& filename,
+                             const std::string& sectionName,
+                             const ConfigSection& section,
+                             bool isDryRun);
+
+  static void
+  ignoreUnknownSection(const std::string& filename,
+                       const std::string& sectionName,
+                       const ConfigSection& section,
+                       bool isDryRun);
+
+public: // parse helpers
+  /** \brief parse a config option that can be either "yes" or "no"
+   *  \retval true "yes"
+   *  \retval false "no"
+   *  \throw Error the value is neither "yes" nor "no"
+   */
+  static bool
+  parseYesNo(const ConfigSection& node, const std::string& key, const std::string& sectionName);
+
+  static bool
+  parseYesNo(const ConfigSection::value_type& option, const std::string& sectionName)
+  {
+    return parseYesNo(option.second, option.first, sectionName);
+  }
+
+  /**
+   * \brief parse a numeric (integral or floating point) config option
+   * \tparam T an arithmetic type
+   *
+   * \return the numeric value of the parsed option
+   * \throw Error the value cannot be converted to the specified type
+   */
+  template<typename T>
+  static T
+  parseNumber(const ConfigSection& node, const std::string& key, const std::string& sectionName)
+  {
+    static_assert(std::is_arithmetic<T>::value, "T must be an arithmetic type");
+
+    boost::optional<T> value = node.get_value_optional<T>();
+    if (value) {
+      return *value;
+    }
+    NDN_THROW(Error("Invalid value '" + node.get_value<std::string>() +
+                    "' for option '" + key + "' in section '" + sectionName + "'"));
+  }
+
+  template <typename T>
+  static T
+  parseNumber(const ConfigSection::value_type& option, const std::string& sectionName)
+  {
+    return parseNumber<T>(option.second, option.first, sectionName);
+  }
+
+public: // setup and parsing
+  /// \brief setup notification of configuration file sections
+  void
+  addSectionHandler(const std::string& sectionName,
+                    ConfigSectionHandler subscriber);
+
+  /**
+   * \param filename file to parse
+   * \param isDryRun true if performing a dry run of configuration, false otherwise
+   * \throws ConfigFile::Error if file not found
+   * \throws ConfigFile::Error if parse error
+   */
+  void
+  parse(const std::string& filename, bool isDryRun);
+
+  /**
+   * \param input configuration (as a string) to parse
+   * \param isDryRun true if performing a dry run of configuration, false otherwise
+   * \param filename logical filename of the config file, can appear in error messages
+   * \throws ConfigFile::Error if file not found
+   * \throws ConfigFile::Error if parse error
+   */
+  void
+  parse(const std::string& input, bool isDryRun, const std::string& filename);
+
+  /**
+   * \param input stream to parse
+   * \param isDryRun true if performing a dry run of configuration, false otherwise
+   * \param filename logical filename of the config file, can appear in error messages
+   * \throws ConfigFile::Error if parse error
+   */
+  void
+  parse(std::istream& input, bool isDryRun, const std::string& filename);
+
+  /**
+   * \param config ConfigSection that needs to be processed
+   * \param isDryRun true if performing a dry run of configuration, false otherwise
+   * \param filename logical filename of the config file, can appear in error messages
+   * \throws ConfigFile::Error if parse error
+   */
+  void
+  parse(const ConfigSection& config, bool isDryRun, const std::string& filename);
+
+private:
+  void
+  process(bool isDryRun, const std::string& filename) const;
+
+private:
+  UnknownConfigSectionHandler m_unknownSectionCallback;
+  std::map<std::string, ConfigSectionHandler> m_subscriptions;
+  ConfigSection m_global;
+};
+
+} // namespace nfd
+
+#endif // NFD_DAEMON_COMMON_CONFIG_FILE_HPP
diff --git a/daemon/common/counter.hpp b/daemon/common/counter.hpp
new file mode 100644
index 0000000..4619b35
--- /dev/null
+++ b/daemon/common/counter.hpp
@@ -0,0 +1,134 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2019,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef NFD_DAEMON_COMMON_COUNTER_HPP
+#define NFD_DAEMON_COMMON_COUNTER_HPP
+
+#include "core/common.hpp"
+
+namespace nfd {
+
+/** \brief represents a counter that encloses an integer value
+ *
+ *  SimpleCounter is noncopyable, because increment should be called on the counter,
+ *  not a copy of it; it's implicitly convertible to an integral type to be observed
+ */
+class SimpleCounter : noncopyable
+{
+public:
+  typedef uint64_t rep;
+
+  /** \brief observe the counter
+   */
+  operator rep() const noexcept
+  {
+    return m_value;
+  }
+
+  /** \brief replace the counter value
+   */
+  void
+  set(rep value) noexcept
+  {
+    m_value = value;
+  }
+
+protected:
+  rep m_value = 0;
+};
+
+/** \brief represents a counter of number of packets
+ *
+ *  \warning The counter value may wrap after exceeding the range of underlying integer type.
+ */
+class PacketCounter : public SimpleCounter
+{
+public:
+  /** \brief increment the counter by one
+   */
+  PacketCounter&
+  operator++() noexcept
+  {
+    ++m_value;
+    return *this;
+  }
+  // postfix ++ operator is not provided because it's not needed
+};
+
+/** \brief represents a counter of number of bytes
+ *
+ *  \warning The counter value may wrap after exceeding the range of underlying integer type.
+ */
+class ByteCounter : public SimpleCounter
+{
+public:
+  /** \brief increase the counter
+   */
+  ByteCounter&
+  operator+=(rep n) noexcept
+  {
+    m_value += n;
+    return *this;
+  }
+};
+
+/** \brief provides a counter that observes the size of a table
+ *  \tparam T a type that provides a size() const member function
+ *
+ *  if table not specified in constructor, it can be added later by invoking observe()
+ */
+template<typename T>
+class SizeCounter : noncopyable
+{
+public:
+  typedef size_t Rep;
+
+  explicit constexpr
+  SizeCounter(const T* table = nullptr) noexcept
+    : m_table(table)
+  {
+  }
+
+  void
+  observe(const T* table) noexcept
+  {
+    m_table = table;
+  }
+
+  /** \brief observe the counter
+   */
+  operator Rep() const
+  {
+    BOOST_ASSERT(m_table != nullptr);
+    return m_table->size();
+  }
+
+private:
+  const T* m_table;
+};
+
+} // namespace nfd
+
+#endif // NFD_DAEMON_COMMON_COUNTER_HPP
diff --git a/daemon/common/global.cpp b/daemon/common/global.cpp
new file mode 100644
index 0000000..a0fd88f
--- /dev/null
+++ b/daemon/common/global.cpp
@@ -0,0 +1,100 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2019,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "common/global.hpp"
+
+namespace nfd {
+
+static thread_local unique_ptr<boost::asio::io_service> g_ioService;
+static thread_local unique_ptr<Scheduler> g_scheduler;
+static boost::asio::io_service* g_mainIoService = nullptr;
+static boost::asio::io_service* g_ribIoService = nullptr;
+
+boost::asio::io_service&
+getGlobalIoService()
+{
+  if (g_ioService == nullptr) {
+    g_ioService = make_unique<boost::asio::io_service>();
+  }
+  return *g_ioService;
+}
+
+Scheduler&
+getScheduler()
+{
+  if (g_scheduler == nullptr) {
+    g_scheduler = make_unique<Scheduler>(getGlobalIoService());
+  }
+  return *g_scheduler;
+}
+
+#ifdef WITH_TESTS
+void
+resetGlobalIoService()
+{
+  g_scheduler.reset();
+  g_ioService.reset();
+}
+#endif
+
+boost::asio::io_service&
+getMainIoService()
+{
+  BOOST_ASSERT(g_mainIoService != nullptr);
+  return *g_mainIoService;
+}
+
+boost::asio::io_service&
+getRibIoService()
+{
+  BOOST_ASSERT(g_ribIoService != nullptr);
+  return *g_ribIoService;
+}
+
+void
+setMainIoService(boost::asio::io_service* mainIo)
+{
+  g_mainIoService = mainIo;
+}
+
+void
+setRibIoService(boost::asio::io_service* ribIo)
+{
+  g_ribIoService = ribIo;
+}
+
+void
+runOnMainIoService(const std::function<void()>& f)
+{
+  getMainIoService().post(f);
+}
+
+void
+runOnRibIoService(const std::function<void()>& f)
+{
+  getRibIoService().post(f);
+}
+
+} // namespace nfd
diff --git a/daemon/common/global.hpp b/daemon/common/global.hpp
new file mode 100644
index 0000000..1e1fce8
--- /dev/null
+++ b/daemon/common/global.hpp
@@ -0,0 +1,75 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2019  Regents of the University of California,
+ *                          Arizona Board of Regents,
+ *                          Colorado State University,
+ *                          University Pierre & Marie Curie, Sorbonne University,
+ *                          Washington University in St. Louis,
+ *                          Beijing Institute of Technology
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+#ifndef NFD_DAEMON_COMMON_GLOBAL_HPP
+#define NFD_DAEMON_COMMON_GLOBAL_HPP
+
+#include "core/common.hpp"
+
+namespace nfd {
+
+/** \brief Returns the global io_service instance for the calling thread.
+ */
+boost::asio::io_service&
+getGlobalIoService();
+
+/** \brief Returns the global Scheduler instance for the calling thread.
+ */
+Scheduler&
+getScheduler();
+
+boost::asio::io_service&
+getMainIoService();
+
+boost::asio::io_service&
+getRibIoService();
+
+void
+setMainIoService(boost::asio::io_service* mainIo);
+
+void
+setRibIoService(boost::asio::io_service* ribIo);
+
+/** \brief Run a function on the main io_service instance.
+ */
+void
+runOnMainIoService(const std::function<void()>& f);
+
+/** \brief Run a function on the RIB io_service instance.
+ */
+void
+runOnRibIoService(const std::function<void()>& f);
+
+#ifdef WITH_TESTS
+/** \brief Destroy the global io_service instance.
+ *
+ *  It will be recreated at the next invocation of getGlobalIoService().
+ */
+void
+resetGlobalIoService();
+#endif
+
+} // namespace nfd
+
+#endif // NFD_DAEMON_COMMON_GLOBAL_HPP
diff --git a/daemon/common/logger.hpp b/daemon/common/logger.hpp
new file mode 100644
index 0000000..9a2637d
--- /dev/null
+++ b/daemon/common/logger.hpp
@@ -0,0 +1,44 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2019,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef NFD_DAEMON_COMMON_LOGGER_HPP
+#define NFD_DAEMON_COMMON_LOGGER_HPP
+
+#include <ndn-cxx/util/logger.hpp>
+
+#define NFD_LOG_INIT(name)                         NDN_LOG_INIT(nfd.name)
+#define NFD_LOG_MEMBER_DECL()                      NDN_LOG_MEMBER_DECL()
+#define NFD_LOG_MEMBER_DECL_SPECIALIZED(cls)       NDN_LOG_MEMBER_DECL_SPECIALIZED(cls)
+#define NFD_LOG_MEMBER_INIT(cls, name)             NDN_LOG_MEMBER_INIT(cls, nfd.name)
+#define NFD_LOG_MEMBER_INIT_SPECIALIZED(cls, name) NDN_LOG_MEMBER_INIT_SPECIALIZED(cls, nfd.name)
+
+#define NFD_LOG_TRACE NDN_LOG_TRACE
+#define NFD_LOG_DEBUG NDN_LOG_DEBUG
+#define NFD_LOG_INFO  NDN_LOG_INFO
+#define NFD_LOG_WARN  NDN_LOG_WARN
+#define NFD_LOG_ERROR NDN_LOG_ERROR
+#define NFD_LOG_FATAL NDN_LOG_FATAL
+
+#endif // NFD_DAEMON_COMMON_LOGGER_HPP
diff --git a/daemon/common/privilege-helper.cpp b/daemon/common/privilege-helper.cpp
new file mode 100644
index 0000000..7cdfcd0
--- /dev/null
+++ b/daemon/common/privilege-helper.cpp
@@ -0,0 +1,163 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2019,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "common/privilege-helper.hpp"
+#include "common/logger.hpp"
+
+#include <pwd.h>
+#include <grp.h>
+
+namespace nfd {
+
+NFD_LOG_INIT(PrivilegeHelper);
+
+#ifdef HAVE_PRIVILEGE_DROP_AND_ELEVATE
+uid_t PrivilegeHelper::s_normalUid = ::geteuid();
+gid_t PrivilegeHelper::s_normalGid = ::getegid();
+
+uid_t PrivilegeHelper::s_privilegedUid = ::geteuid();
+gid_t PrivilegeHelper::s_privilegedGid = ::getegid();
+#endif // HAVE_PRIVILEGE_DROP_AND_ELEVATE
+
+void
+PrivilegeHelper::initialize(const std::string& userName, const std::string& groupName)
+{
+#ifdef HAVE_PRIVILEGE_DROP_AND_ELEVATE
+  static const size_t MAX_GROUP_BUFFER_SIZE = 16384; // 16 KiB
+  static const size_t MAX_PASSWD_BUFFER_SIZE = 16384;
+
+  static const size_t FALLBACK_GROUP_BUFFER_SIZE = 1024;
+  static const size_t FALLBACK_PASSWD_BUFFER_SIZE = 1024;
+
+  NFD_LOG_TRACE("initializing with user \"" << userName << "\""
+                << " group \"" << groupName << "\"");
+
+  // workflow from man getpwnam_r
+
+  if (!groupName.empty()) {
+    static long groupSize = ::sysconf(_SC_GETGR_R_SIZE_MAX);
+
+    if (groupSize == -1)
+      groupSize = FALLBACK_GROUP_BUFFER_SIZE;
+
+    std::vector<char> groupBuffer(static_cast<size_t>(groupSize));
+    struct group group;
+    struct group* groupResult = nullptr;
+
+    int errorCode = getgrnam_r(groupName.data(), &group,
+                               groupBuffer.data(), groupBuffer.size(), &groupResult);
+
+    while (errorCode == ERANGE) {
+      if (groupBuffer.size() * 2 > MAX_GROUP_BUFFER_SIZE)
+        throw Error("Cannot allocate large enough buffer for struct group");
+
+      groupBuffer.resize(groupBuffer.size() * 2);
+      errorCode = getgrnam_r(groupName.data(), &group,
+                             groupBuffer.data(), groupBuffer.size(), &groupResult);
+    }
+
+    if (errorCode != 0 || !groupResult)
+      throw Error("Failed to get gid for \"" + groupName + "\"");
+
+    s_normalGid = group.gr_gid;
+  }
+
+  if (!userName.empty()) {
+    static long passwdSize = ::sysconf(_SC_GETPW_R_SIZE_MAX);
+
+    if (passwdSize == -1)
+      passwdSize = FALLBACK_PASSWD_BUFFER_SIZE;
+
+    std::vector<char> passwdBuffer(static_cast<size_t>(passwdSize));
+    struct passwd passwd;
+    struct passwd* passwdResult = nullptr;
+
+    int errorCode = getpwnam_r(userName.data(), &passwd,
+                               passwdBuffer.data(), passwdBuffer.size(), &passwdResult);
+
+    while (errorCode == ERANGE) {
+      if (passwdBuffer.size() * 2 > MAX_PASSWD_BUFFER_SIZE)
+        throw Error("Cannot allocate large enough buffer for struct passwd");
+
+      passwdBuffer.resize(passwdBuffer.size() * 2);
+      errorCode = getpwnam_r(userName.data(), &passwd,
+                             passwdBuffer.data(), passwdBuffer.size(), &passwdResult);
+    }
+
+    if (errorCode != 0 || !passwdResult)
+      throw Error("Failed to get uid for \"" + userName + "\"");
+
+    s_normalUid = passwd.pw_uid;
+  }
+#else
+  if (!userName.empty() || !groupName.empty()) {
+    throw Error("Dropping and raising privileges is not supported on this platform");
+  }
+#endif // HAVE_PRIVILEGE_DROP_AND_ELEVATE
+}
+
+void
+PrivilegeHelper::drop()
+{
+#ifdef HAVE_PRIVILEGE_DROP_AND_ELEVATE
+  if (::geteuid() == s_normalUid && ::getegid() == s_normalGid)
+    return;
+
+  NFD_LOG_TRACE("dropping to effective gid=" << s_normalGid);
+  if (::setegid(s_normalGid) != 0)
+    throw Error("Failed to drop to effective gid=" + to_string(s_normalGid));
+
+  NFD_LOG_TRACE("dropping to effective uid=" << s_normalUid);
+  if (::seteuid(s_normalUid) != 0)
+    throw Error("Failed to drop to effective uid=" + to_string(s_normalUid));
+
+  NFD_LOG_INFO("dropped to effective uid=" << ::geteuid() << " gid=" << ::getegid());
+#else
+  NFD_LOG_WARN("Dropping privileges is not supported on this platform");
+#endif // HAVE_PRIVILEGE_DROP_AND_ELEVATE
+}
+
+void
+PrivilegeHelper::raise()
+{
+#ifdef HAVE_PRIVILEGE_DROP_AND_ELEVATE
+  if (::geteuid() == s_privilegedUid && ::getegid() == s_privilegedGid)
+    return;
+
+  NFD_LOG_TRACE("elevating to effective uid=" << s_privilegedUid);
+  if (::seteuid(s_privilegedUid) != 0)
+    throw Error("Failed to elevate to effective uid=" + to_string(s_privilegedUid));
+
+  NFD_LOG_TRACE("elevating to effective gid=" << s_privilegedGid);
+  if (::setegid(s_privilegedGid) != 0)
+    throw Error("Failed to elevate to effective gid=" + to_string(s_privilegedGid));
+
+  NFD_LOG_INFO("elevated to effective uid=" << ::geteuid() << " gid=" << ::getegid());
+#else
+  NFD_LOG_WARN("Elevating privileges is not supported on this platform");
+#endif // HAVE_PRIVILEGE_DROP_AND_ELEVATE
+}
+
+} // namespace nfd
diff --git a/daemon/common/privilege-helper.hpp b/daemon/common/privilege-helper.hpp
new file mode 100644
index 0000000..52daf84
--- /dev/null
+++ b/daemon/common/privilege-helper.hpp
@@ -0,0 +1,99 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2019,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef NFD_DAEMON_COMMON_PRIVILEGE_HELPER_HPP
+#define NFD_DAEMON_COMMON_PRIVILEGE_HELPER_HPP
+
+#include "core/common.hpp"
+
+#include <unistd.h>
+
+namespace nfd {
+
+class PrivilegeHelper
+{
+public:
+  /** \brief represents a serious seteuid/gid failure
+   *
+   *  This should only be caught by main as part of a graceful program termination.
+   *  \note This is not an std::exception and NDN_THROW should not be used.
+   */
+  class Error
+  {
+  public:
+    explicit
+    Error(const std::string& what)
+      : m_whatMessage(what)
+    {
+    }
+
+    const char*
+    what() const
+    {
+      return m_whatMessage.data();
+    }
+
+  private:
+    const std::string m_whatMessage;
+  };
+
+  static void
+  initialize(const std::string& userName, const std::string& groupName);
+
+  static void
+  drop();
+
+  template<class F>
+  static void
+  runElevated(F&& f)
+  {
+    raise();
+    try {
+      f();
+    }
+    catch (...) {
+      drop();
+      throw;
+    }
+    drop();
+  }
+
+PUBLIC_WITH_TESTS_ELSE_PRIVATE:
+  static void
+  raise();
+
+PUBLIC_WITH_TESTS_ELSE_PRIVATE:
+#ifdef HAVE_PRIVILEGE_DROP_AND_ELEVATE
+  static uid_t s_normalUid;
+  static gid_t s_normalGid;
+
+  static uid_t s_privilegedUid;
+  static gid_t s_privilegedGid;
+#endif // HAVE_PRIVILEGE_DROP_AND_ELEVATE
+};
+
+} // namespace nfd
+
+#endif // NFD_DAEMON_COMMON_PRIVILEGE_HELPER_HPP