Add IPv4 classes

3 files changed, 593 insertions, 0 deletions

diff --git a/src/common/ip.cpp b/src/common/ip.cpp
new file mode 100644
index 0000000..4734a8b
--- /dev/null
+++ b/src/common/ip.cpp
@@ -0,0 +1,111 @@
+#include "ip.hpp"
+//    ip.cpp - Implementation of IP address functions.
+//
+//    Copyright © 2013 Ben Longbons <b.r.longbons@gmail.com>
+//
+//    This file is part of The Mana World (Athena server)
+//
+//    This program 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.
+//
+//    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include "cxxstdio.hpp"
+
+#include "../poison.hpp"
+
+bool extract(XString str, IP4Address *rv)
+{
+    if (str.endswith('.'))
+        return false;
+    uint8_t buf[4];
+    if (extract(str, record<'.'>(&buf[0], &buf[1], &buf[2], &buf[3])))
+    {
+        *rv = IP4Address(buf);
+        return true;
+    }
+    return false;
+}
+
+bool extract(XString str, IP4Mask *rv)
+{
+    IP4Address a, m;
+    unsigned b;
+    XString l, r;
+    if (str.endswith('/'))
+        return false;
+    if (extract(str, record<'/'>(&l, &r)))
+    {
+        // a.b.c.d/e.f.g.h or a.b.c.d/n
+        if (!extract(l, &a))
+            return false;
+        if (extract(r, &m))
+        {
+            *rv = IP4Mask(a, m);
+            return true;
+        }
+        if (!extract(r, &b) || b > 32)
+            return false;
+    }
+    else
+    {
+        // a.b.c.d or a.b.c.d. or a.b.c. or a.b. or a.
+        if (extract(str, &a))
+        {
+            *rv = IP4Mask(a, IP4_BROADCAST);
+            return true;
+        }
+        if (!str.endswith('.'))
+            return false;
+        uint8_t d[4] {};
+        if (extract(str, record<'.'>(&d[0], &d[1], &d[2], &d[3])))
+            b = 32;
+        else if (extract(str, record<'.'>(&d[0], &d[1], &d[2])))
+            b = 24;
+        else if (extract(str, record<'.'>(&d[0], &d[1])))
+            b = 16;
+        else if (extract(str, record<'.'>(&d[0])))
+            b = 8;
+        else
+            return false;
+        a = IP4Address(d);
+    }
+    // a is set; need to construct m from b
+    if (b == 0)
+        m = IP4Address();
+    else if (b == 32)
+        m = IP4_BROADCAST;
+    else
+    {
+        uint32_t s = -1;
+        s <<= (32 - b);
+        m = IP4Address({
+                static_cast<uint8_t>(s >> 24),
+                static_cast<uint8_t>(s >> 16),
+                static_cast<uint8_t>(s >> 8),
+                static_cast<uint8_t>(s >> 0),
+        });
+    }
+    *rv = IP4Mask(a, m);
+    return true;
+}
+
+VString<15> convert_for_printf(IP4Address a_)
+{
+    const uint8_t *a = a_.bytes();
+    return STRNPRINTF(16, "%hhu.%hhu.%hhu.%hhu", a[0], a[1], a[2], a[3]);
+}
+
+VString<31> convert_for_printf(IP4Mask a)
+{
+    return STRNPRINTF(32, "%s/%s",
+            a.addr(), a.mask());
+}
diff --git a/src/common/ip.hpp b/src/common/ip.hpp
new file mode 100644
index 0000000..e67056c
--- /dev/null
+++ b/src/common/ip.hpp
@@ -0,0 +1,150 @@
+#ifndef TMWA_COMMON_IP_HPP
+#define TMWA_COMMON_IP_HPP
+//    ip.hpp - classes to deal with IP addresses.
+//
+//    Copyright © 2013 Ben Longbons <b.r.longbons@gmail.com>
+//
+//    This file is part of The Mana World (Athena server)
+//
+//    This program 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.
+//
+//    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include "sanity.hpp"
+
+#include "extract.hpp"
+#include "strings.hpp"
+
+// TODO - in the long run ports belong here also
+// and of course, IPv6 stuff.
+// But what about unix socket addresses?
+
+/// Helper function
+template<class T, size_t n>
+constexpr
+bool _ce_a_lt(T (&a)[n], T (&b)[n], size_t i=0)
+{
+    return (i != n
+            && (a[i] < b[i]
+                || (a[i] == b[i]
+                    && _ce_a_lt(a, b, i + 1))));
+}
+
+/// A 32-bit Ipv4 address. Does not include a port.
+/// Guaranteed to be laid out like the network wants.
+class IP4Address
+{
+    uint8_t _addr[4];
+public:
+    constexpr
+    IP4Address()
+    : _addr{}
+    {}
+    constexpr explicit
+    IP4Address(const uint8_t (&a)[4])
+    : _addr{a[0], a[1], a[2], a[3]}
+    {}
+
+    constexpr friend
+    IP4Address operator & (IP4Address l, IP4Address r)
+    {
+        return IP4Address({
+                static_cast<uint8_t>(l._addr[0] & r._addr[0]),
+                static_cast<uint8_t>(l._addr[1] & r._addr[1]),
+                static_cast<uint8_t>(l._addr[2] & r._addr[2]),
+                static_cast<uint8_t>(l._addr[3] & r._addr[3]),
+        });
+    }
+
+    IP4Address& operator &= (IP4Address m)
+    { return *this = *this & m; }
+
+    const uint8_t *bytes() const
+    { return _addr; }
+
+    constexpr friend
+    bool operator < (IP4Address l, IP4Address r)
+    {
+        return _ce_a_lt(l._addr, r._addr);
+    }
+
+    constexpr friend
+    bool operator > (IP4Address l, IP4Address r)
+    {
+        return _ce_a_lt(r._addr, l._addr);
+    }
+
+    constexpr friend
+    bool operator >= (IP4Address l, IP4Address r)
+    {
+        return !_ce_a_lt(l._addr, r._addr);
+    }
+
+    constexpr friend
+    bool operator <= (IP4Address l, IP4Address r)
+    {
+        return !_ce_a_lt(r._addr, l._addr);
+    }
+
+    constexpr friend
+    bool operator == (IP4Address l, IP4Address r)
+    {
+        return !(l < r || r < l);
+    }
+
+    constexpr friend
+    bool operator != (IP4Address l, IP4Address r)
+    {
+        return (l < r || r < l);
+    }
+};
+
+class IP4Mask
+{
+    IP4Address _addr, _mask;
+public:
+    constexpr
+    IP4Mask() : _addr(), _mask()
+    {}
+    constexpr
+    IP4Mask(IP4Address a, IP4Address m) : _addr(a & m), _mask(m)
+    {}
+
+    constexpr
+    IP4Address addr() const
+    { return _addr; }
+    constexpr
+    IP4Address mask() const
+    { return _mask; }
+
+    constexpr
+    bool covers(IP4Address a) const
+    {
+        return (a & _mask) == _addr;
+    }
+};
+
+
+constexpr
+IP4Address IP4_LOCALHOST({127, 0, 0, 1});
+constexpr
+IP4Address IP4_BROADCAST({255, 255, 255, 255});
+
+
+VString<15> convert_for_printf(IP4Address a);
+VString<31> convert_for_printf(IP4Mask m);
+
+bool extract(XString str, IP4Address *iv);
+
+bool extract(XString str, IP4Mask *iv);
+
+#endif // TMWA_COMMON_IP_HPP
diff --git a/src/common/ip_test.cpp b/src/common/ip_test.cpp
new file mode 100644
index 0000000..64a537f
--- /dev/null
+++ b/src/common/ip_test.cpp
@@ -0,0 +1,332 @@
+#include "ip.hpp"
+
+#include <gtest/gtest.h>
+
+#include "cxxstdio.hpp"
+
+#define CB(X) (std::integral_constant<bool, (X)>::value)
+TEST(ip4addr, cmp)
+{
+    constexpr static
+    IP4Address a = IP4_LOCALHOST;
+    constexpr static
+    IP4Address b = IP4_BROADCAST;
+
+    EXPECT_FALSE(CB(a < a));
+    EXPECT_TRUE (CB(a < b));
+    EXPECT_FALSE(CB(b < a));
+    EXPECT_FALSE(CB(b < b));
+
+    EXPECT_FALSE(CB(a > a));
+    EXPECT_FALSE(CB(a > b));
+    EXPECT_TRUE (CB(b > a));
+    EXPECT_FALSE(CB(b > b));
+
+    EXPECT_TRUE (CB(a <= a));
+    EXPECT_TRUE (CB(a <= b));
+    EXPECT_FALSE(CB(b <= a));
+    EXPECT_TRUE (CB(b <= b));
+
+    EXPECT_TRUE (CB(a >= a));
+    EXPECT_FALSE(CB(a >= b));
+    EXPECT_TRUE (CB(b >= a));
+    EXPECT_TRUE (CB(b >= b));
+
+    EXPECT_TRUE (CB(a == a));
+    EXPECT_FALSE(CB(a == b));
+    EXPECT_FALSE(CB(b == a));
+    EXPECT_TRUE (CB(b == b));
+
+    EXPECT_FALSE(CB(a != a));
+    EXPECT_TRUE (CB(a != b));
+    EXPECT_TRUE (CB(b != a));
+    EXPECT_FALSE(CB(b != b));
+}
+
+TEST(ip4addr, str)
+{
+    IP4Address a;
+    EXPECT_EQ("0.0.0.0", STRNPRINTF(17, "%s", a));
+    EXPECT_EQ("127.0.0.1", STRNPRINTF(17, "%s", IP4_LOCALHOST));
+    EXPECT_EQ("255.255.255.255", STRNPRINTF(17, "%s", IP4_BROADCAST));
+}
+
+TEST(ip4addr, extract)
+{
+    IP4Address a;
+    EXPECT_TRUE(extract("0.0.0.0", &a));
+    EXPECT_EQ("0.0.0.0", STRNPRINTF(16, "%s", a));
+    EXPECT_TRUE(extract("127.0.0.1", &a));
+    EXPECT_EQ("127.0.0.1", STRNPRINTF(16, "%s", a));
+    EXPECT_TRUE(extract("255.255.255.255", &a));
+    EXPECT_EQ("255.255.255.255", STRNPRINTF(16, "%s", a));
+    EXPECT_TRUE(extract("1.2.3.4", &a));
+    EXPECT_EQ("1.2.3.4", STRNPRINTF(16, "%s", a));
+
+    EXPECT_FALSE(extract("1.2.3.4.5", &a));
+    EXPECT_FALSE(extract("1.2.3.4.", &a));
+    EXPECT_FALSE(extract("1.2.3.", &a));
+    EXPECT_FALSE(extract("1.2.3", &a));
+    EXPECT_FALSE(extract("1.2.", &a));
+    EXPECT_FALSE(extract("1.2", &a));
+    EXPECT_FALSE(extract("1.", &a));
+    EXPECT_FALSE(extract("1", &a));
+    EXPECT_FALSE(extract("", &a));
+}
+
+
+TEST(ip4mask, body)
+{
+    IP4Mask m;
+    EXPECT_EQ(IP4Address(), m.addr());
+    EXPECT_EQ(IP4Address(), m.mask());
+    m = IP4Mask(IP4_LOCALHOST, IP4_BROADCAST);
+    EXPECT_EQ(IP4_LOCALHOST, m.addr());
+    EXPECT_EQ(IP4_BROADCAST, m.mask());
+}
+
+TEST(ip4mask, str)
+{
+    IP4Mask m;
+    EXPECT_EQ("0.0.0.0/0.0.0.0", STRNPRINTF(33, "%s", m));
+    m = IP4Mask(IP4_LOCALHOST, IP4_BROADCAST);
+    EXPECT_EQ("127.0.0.1/255.255.255.255", STRNPRINTF(33, "%s", m));
+}
+
+TEST(ip4mask, extract)
+{
+    IP4Mask m;
+    EXPECT_FALSE(extract("9.8.7.6/33", &m));
+    EXPECT_FALSE(extract("9.8.7.6.5", &m));
+    EXPECT_FALSE(extract("9.8.7.6/", &m));
+    EXPECT_FALSE(extract("9.8.7", &m));
+    EXPECT_FALSE(extract("9.8", &m));
+    EXPECT_FALSE(extract("9", &m));
+
+    EXPECT_TRUE(extract("127.0.0.1", &m));
+    EXPECT_EQ("127.0.0.1/255.255.255.255", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("127.0.0.1.", &m));
+    EXPECT_EQ("127.0.0.1/255.255.255.255", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("127.0.0.", &m));
+    EXPECT_EQ("127.0.0.0/255.255.255.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("127.0.", &m));
+    EXPECT_EQ("127.0.0.0/255.255.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("127.", &m));
+    EXPECT_EQ("127.0.0.0/255.0.0.0", STRNPRINTF(32, "%s", m));
+
+    EXPECT_TRUE(extract("1.2.3.4/255.255.255.255", &m));
+    EXPECT_EQ("1.2.3.4/255.255.255.255", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("1.2.3.0/255.255.255.0", &m));
+    EXPECT_EQ("1.2.3.0/255.255.255.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("1.2.0.4/255.255.0.255", &m));
+    EXPECT_EQ("1.2.0.4/255.255.0.255", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("1.2.0.0/255.255.0.0", &m));
+    EXPECT_EQ("1.2.0.0/255.255.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("1.0.3.4/255.0.255.255", &m));
+    EXPECT_EQ("1.0.3.4/255.0.255.255", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("1.0.3.0/255.0.255.0", &m));
+    EXPECT_EQ("1.0.3.0/255.0.255.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("1.0.0.4/255.0.0.255", &m));
+    EXPECT_EQ("1.0.0.4/255.0.0.255", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("1.0.0.0/255.0.0.0", &m));
+    EXPECT_EQ("1.0.0.0/255.0.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.2.3.4/0.255.255.255", &m));
+    EXPECT_EQ("0.2.3.4/0.255.255.255", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.2.3.0/0.255.255.0", &m));
+    EXPECT_EQ("0.2.3.0/0.255.255.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.2.0.4/0.255.0.255", &m));
+    EXPECT_EQ("0.2.0.4/0.255.0.255", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.2.0.0/0.255.0.0", &m));
+    EXPECT_EQ("0.2.0.0/0.255.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.3.4/0.0.255.255", &m));
+    EXPECT_EQ("0.0.3.4/0.0.255.255", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.3.0/0.0.255.0", &m));
+    EXPECT_EQ("0.0.3.0/0.0.255.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.4/0.0.0.255", &m));
+    EXPECT_EQ("0.0.0.4/0.0.0.255", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/0.0.0.0", &m));
+    EXPECT_EQ("0.0.0.0/0.0.0.0", STRNPRINTF(32, "%s", m));
+
+    // please don't do this
+    EXPECT_TRUE(extract("120.248.200.217/89.57.126.5", &m));
+    EXPECT_EQ("88.56.72.1/89.57.126.5", STRNPRINTF(32, "%s", m));
+
+    EXPECT_TRUE(extract("0.0.0.0/32", &m));
+    EXPECT_EQ("0.0.0.0/255.255.255.255", STRNPRINTF(32, "%s", m));
+
+    EXPECT_TRUE(extract("0.0.0.0/31", &m));
+    EXPECT_EQ("0.0.0.0/255.255.255.254", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/30", &m));
+    EXPECT_EQ("0.0.0.0/255.255.255.252", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/29", &m));
+    EXPECT_EQ("0.0.0.0/255.255.255.248", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/28", &m));
+    EXPECT_EQ("0.0.0.0/255.255.255.240", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/27", &m));
+    EXPECT_EQ("0.0.0.0/255.255.255.224", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/26", &m));
+    EXPECT_EQ("0.0.0.0/255.255.255.192", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/25", &m));
+    EXPECT_EQ("0.0.0.0/255.255.255.128", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/24", &m));
+    EXPECT_EQ("0.0.0.0/255.255.255.0", STRNPRINTF(32, "%s", m));
+
+    EXPECT_TRUE(extract("0.0.0.0/23", &m));
+    EXPECT_EQ("0.0.0.0/255.255.254.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/22", &m));
+    EXPECT_EQ("0.0.0.0/255.255.252.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/21", &m));
+    EXPECT_EQ("0.0.0.0/255.255.248.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/20", &m));
+    EXPECT_EQ("0.0.0.0/255.255.240.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/19", &m));
+    EXPECT_EQ("0.0.0.0/255.255.224.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/18", &m));
+    EXPECT_EQ("0.0.0.0/255.255.192.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/17", &m));
+    EXPECT_EQ("0.0.0.0/255.255.128.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/16", &m));
+    EXPECT_EQ("0.0.0.0/255.255.0.0", STRNPRINTF(32, "%s", m));
+
+    EXPECT_TRUE(extract("0.0.0.0/15", &m));
+    EXPECT_EQ("0.0.0.0/255.254.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/14", &m));
+    EXPECT_EQ("0.0.0.0/255.252.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/13", &m));
+    EXPECT_EQ("0.0.0.0/255.248.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/12", &m));
+    EXPECT_EQ("0.0.0.0/255.240.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/11", &m));
+    EXPECT_EQ("0.0.0.0/255.224.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/10", &m));
+    EXPECT_EQ("0.0.0.0/255.192.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/9", &m));
+    EXPECT_EQ("0.0.0.0/255.128.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/8", &m));
+    EXPECT_EQ("0.0.0.0/255.0.0.0", STRNPRINTF(32, "%s", m));
+
+    EXPECT_TRUE(extract("0.0.0.0/7", &m));
+    EXPECT_EQ("0.0.0.0/254.0.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/6", &m));
+    EXPECT_EQ("0.0.0.0/252.0.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/5", &m));
+    EXPECT_EQ("0.0.0.0/248.0.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/4", &m));
+    EXPECT_EQ("0.0.0.0/240.0.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/3", &m));
+    EXPECT_EQ("0.0.0.0/224.0.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/2", &m));
+    EXPECT_EQ("0.0.0.0/192.0.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/1", &m));
+    EXPECT_EQ("0.0.0.0/128.0.0.0", STRNPRINTF(32, "%s", m));
+    EXPECT_TRUE(extract("0.0.0.0/0", &m));
+    EXPECT_EQ("0.0.0.0/0.0.0.0", STRNPRINTF(32, "%s", m));
+}
+
+TEST(ip4mask, cover)
+{
+    IP4Address a;
+    IP4Address b = IP4_BROADCAST;
+    IP4Address l = IP4_LOCALHOST;
+    IP4Address h({127, 255, 255, 255});
+    IP4Address p24l({10, 0, 0, 0});
+    IP4Address p24h({10, 255, 255, 255});
+    IP4Address p20l({172, 16, 0, 0});
+    IP4Address p20h({172, 31, 255, 255});
+    IP4Address p16l({192, 168, 0, 0});
+    IP4Address p16h({192, 168, 255, 255});
+    IP4Mask m;
+    EXPECT_TRUE(m.covers(a));
+    EXPECT_TRUE(m.covers(b));
+    EXPECT_TRUE(m.covers(l));
+    EXPECT_TRUE(m.covers(h));
+    EXPECT_TRUE(m.covers(p24l));
+    EXPECT_TRUE(m.covers(p24h));
+    EXPECT_TRUE(m.covers(p20l));
+    EXPECT_TRUE(m.covers(p20h));
+    EXPECT_TRUE(m.covers(p16l));
+    EXPECT_TRUE(m.covers(p16h));
+    m = IP4Mask(l, a);
+    EXPECT_TRUE(m.covers(a));
+    EXPECT_TRUE(m.covers(b));
+    EXPECT_TRUE(m.covers(l));
+    EXPECT_TRUE(m.covers(h));
+    EXPECT_TRUE(m.covers(p24l));
+    EXPECT_TRUE(m.covers(p24h));
+    EXPECT_TRUE(m.covers(p20l));
+    EXPECT_TRUE(m.covers(p20h));
+    EXPECT_TRUE(m.covers(p16l));
+    EXPECT_TRUE(m.covers(p16h));
+    m = IP4Mask(l, b);
+    EXPECT_FALSE(m.covers(a));
+    EXPECT_FALSE(m.covers(b));
+    EXPECT_TRUE(m.covers(l));
+    EXPECT_FALSE(m.covers(h));
+    EXPECT_FALSE(m.covers(p24l));
+    EXPECT_FALSE(m.covers(p24h));
+    EXPECT_FALSE(m.covers(p20l));
+    EXPECT_FALSE(m.covers(p20h));
+    EXPECT_FALSE(m.covers(p16l));
+    EXPECT_FALSE(m.covers(p16h));
+
+    // but the really useful ones are with partial masks
+    m = IP4Mask(IP4Address({10, 0, 0, 0}), IP4Address({255, 0, 0, 0}));
+    EXPECT_FALSE(m.covers(a));
+    EXPECT_FALSE(m.covers(b));
+    EXPECT_FALSE(m.covers(l));
+    EXPECT_FALSE(m.covers(h));
+    EXPECT_TRUE(m.covers(p24l));
+    EXPECT_TRUE(m.covers(p24h));
+    EXPECT_FALSE(m.covers(p20l));
+    EXPECT_FALSE(m.covers(p20h));
+    EXPECT_FALSE(m.covers(p16l));
+    EXPECT_FALSE(m.covers(p16h));
+    EXPECT_FALSE(m.covers(IP4Address({9, 255, 255, 255})));
+    EXPECT_FALSE(m.covers(IP4Address({11, 0, 0, 0})));
+    m = IP4Mask(IP4Address({127, 0, 0, 0}), IP4Address({255, 0, 0, 0}));
+    EXPECT_FALSE(m.covers(a));
+    EXPECT_FALSE(m.covers(b));
+    EXPECT_TRUE(m.covers(l));
+    EXPECT_TRUE(m.covers(h));
+    EXPECT_FALSE(m.covers(p24l));
+    EXPECT_FALSE(m.covers(p24h));
+    EXPECT_FALSE(m.covers(p20l));
+    EXPECT_FALSE(m.covers(p20h));
+    EXPECT_FALSE(m.covers(p16l));
+    EXPECT_FALSE(m.covers(p16h));
+    EXPECT_FALSE(m.covers(IP4Address({126, 255, 255, 255})));
+    EXPECT_FALSE(m.covers(IP4Address({128, 0, 0, 0})));
+    m = IP4Mask(IP4Address({172, 16, 0, 0}), IP4Address({255, 240, 0, 0}));
+    EXPECT_FALSE(m.covers(a));
+    EXPECT_FALSE(m.covers(b));
+    EXPECT_FALSE(m.covers(l));
+    EXPECT_FALSE(m.covers(h));
+    EXPECT_FALSE(m.covers(p24l));
+    EXPECT_FALSE(m.covers(p24h));
+    EXPECT_TRUE(m.covers(p20l));
+    EXPECT_TRUE(m.covers(p20h));
+    EXPECT_FALSE(m.covers(p16l));
+    EXPECT_FALSE(m.covers(p16h));
+    EXPECT_FALSE(m.covers(IP4Address({172, 15, 255, 255})));
+    EXPECT_FALSE(m.covers(IP4Address({172, 32, 0, 0})));
+    m = IP4Mask(IP4Address({192, 168, 0, 0}), IP4Address({255, 255, 0, 0}));
+    EXPECT_FALSE(m.covers(a));
+    EXPECT_FALSE(m.covers(b));
+    EXPECT_FALSE(m.covers(l));
+    EXPECT_FALSE(m.covers(h));
+    EXPECT_FALSE(m.covers(p24l));
+    EXPECT_FALSE(m.covers(p24h));
+    EXPECT_FALSE(m.covers(p20l));
+    EXPECT_FALSE(m.covers(p20h));
+    EXPECT_TRUE(m.covers(p16l));
+    EXPECT_TRUE(m.covers(p16h));
+    EXPECT_FALSE(m.covers(IP4Address({192, 167, 255, 255})));
+    EXPECT_FALSE(m.covers(IP4Address({192, 169, 0, 0})));
+
+    // OTOH this is crazy
+    EXPECT_TRUE(extract("120.248.200.217/89.57.126.5", &m));
+    EXPECT_TRUE(m.covers(IP4Address({120, 248, 200, 217})));
+    EXPECT_TRUE(m.covers(IP4Address({88, 56, 72, 1})));
+    EXPECT_FALSE(m.covers(IP4Address({88, 56, 72, 0})));
+    EXPECT_FALSE(m.covers(IP4Address({88, 56, 72, 255})));
+}