Merge #18077: net: Add NAT-PMP port forwarding support

a191e23b8e7f0e19fc0359825eb7ca0d47966fa9 doc: Add release notes (Hennadii Stepanov)
ae749d12ddbaf592fbdb65d98ca35a0ff5566992 doc: Add libnatpmp stuff (Hennadii Stepanov)
e28f9be87a0f3c59a9184d602fe7947526df6a97 ci: Add libnatpmp-dev package to some builds (Hennadii Stepanov)
5a0185b6c9c838290103314916190a0330ed9a82 gui: Add NAT-PMP network option (Hennadii Stepanov)
a39f7336a3b493d46a4486c4c94fdca1b3151370 net: Add -natpmp command line option (Hennadii Stepanov)
28acffd9d53ec437e908abb8c84497a4f41b91ed net: Add NAT-PMP to port mapping loop (Hennadii Stepanov)
a8d9f275d0ca64797cc89627f8003b48b3efef63 net: Add libnatpmp support (Hennadii Stepanov)
58e8364dcdc4e57b0caac09f8402e6535301de9b gui: Apply port mapping changes on dialog exit (Hennadii Stepanov)
cf151cc68c95a8943e43e3fa4061e176262779e7 scripted-diff: Rename UPnP stuff (Hennadii Stepanov)
4e91b1e24d96e0cdccdd2a3ed034413f3ba6bae6 net: Add flags for port mapping protocols (Hennadii Stepanov)
8b50d1b5bb29b7d1ea0245ba75a8df3144e312dc net: Keep trying to use UPnP when -upnp=1 (Hennadii Stepanov)
28e2961fd6a2a9101fc08fb748430989291aaf7e refactor: Replace magic number with named constant (Hennadii Stepanov)
02ccf69dd6b772423acb343d16ef2bdbb3e3da03 refactor: Move port mapping code to its own module (Hennadii Stepanov)

Pull request description:

  Close #11902
  This PR is an alternative to:
  - #12288
  - #15717

  To compile with NAT-PMP support on Ubuntu [`libnatpmp-dev`](https://packages.ubuntu.com/source/bionic/libnatpmp) should be available.

  Log excerpt:
  ```
  2020-02-05T20:12:28Z [mapport] NAT-PMP: public address = 95.164.65.194
  2020-02-05T20:12:28Z [mapport] AddLocal(95.164.65.194:18333,3)
  2020-02-05T20:12:28Z [mapport] NAT-PMP: port mapping successful.
  ```

  See: [`libnatpmp`](https://miniupnp.tuxfamily.org/libnatpmp.html)

  ---

  Some follow-ups are out of this PR's scope:
  - mention NAT-PMP library in the version message
  - ~integrate NAT-PMP into the GUI~ (already [added](https://github.com/bitcoin/bitcoin/pull/18077#issuecomment-589405068))

ACKs for top commit:
  laanwj:
    Tested and code review ACK a191e23b8e7f0e19fc0359825eb7ca0d47966fa9

Tree-SHA512: 10e19267c21bf30f20ff1abfc882d526049f0e790b95e12f109dc2bed7c0aef45de03eaf967f4e667e7509be04f1873a5c508087393d947205f3aab2ad6d7cf1

1 files changed, 336 insertions, 0 deletions

diff --git a/src/mapport.cpp b/src/mapport.cpp
new file mode 100644
index 0000000000..2df4ce45d2
--- /dev/null
+++ b/src/mapport.cpp
@@ -0,0 +1,336 @@
+// Copyright (c) 2011-2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#if defined(HAVE_CONFIG_H)
+#include <config/bitcoin-config.h>
+#endif
+
+#include <mapport.h>
+
+#include <clientversion.h>
+#include <logging.h>
+#include <net.h>
+#include <netaddress.h>
+#include <netbase.h>
+#include <threadinterrupt.h>
+#include <util/system.h>
+
+#ifdef USE_NATPMP
+#include <compat.h>
+#include <natpmp.h>
+#endif // USE_NATPMP
+
+#ifdef USE_UPNP
+#include <miniupnpc/miniupnpc.h>
+#include <miniupnpc/upnpcommands.h>
+#include <miniupnpc/upnperrors.h>
+// The minimum supported miniUPnPc API version is set to 10. This keeps compatibility
+// with Ubuntu 16.04 LTS and Debian 8 libminiupnpc-dev packages.
+static_assert(MINIUPNPC_API_VERSION >= 10, "miniUPnPc API version >= 10 assumed");
+#endif // USE_UPNP
+
+#include <atomic>
+#include <cassert>
+#include <chrono>
+#include <functional>
+#include <string>
+#include <thread>
+
+#if defined(USE_NATPMP) || defined(USE_UPNP)
+static CThreadInterrupt g_mapport_interrupt;
+static std::thread g_mapport_thread;
+static std::atomic_uint g_mapport_enabled_protos{MapPortProtoFlag::NONE};
+static std::atomic<MapPortProtoFlag> g_mapport_current_proto{MapPortProtoFlag::NONE};
+
+using namespace std::chrono_literals;
+static constexpr auto PORT_MAPPING_REANNOUNCE_PERIOD{20min};
+static constexpr auto PORT_MAPPING_RETRY_PERIOD{5min};
+
+#ifdef USE_NATPMP
+static uint16_t g_mapport_external_port = 0;
+static bool NatpmpInit(natpmp_t* natpmp)
+{
+    const int r_init = initnatpmp(natpmp, /* detect gateway automatically */ 0, /* forced gateway - NOT APPLIED*/ 0);
+    if (r_init == 0) return true;
+    LogPrintf("natpmp: initnatpmp() failed with %d error.\n", r_init);
+    return false;
+}
+
+static bool NatpmpDiscover(natpmp_t* natpmp, struct in_addr& external_ipv4_addr)
+{
+    const int r_send = sendpublicaddressrequest(natpmp);
+    if (r_send == 2 /* OK */) {
+        int r_read;
+        natpmpresp_t response;
+        do {
+            r_read = readnatpmpresponseorretry(natpmp, &response);
+        } while (r_read == NATPMP_TRYAGAIN);
+
+        if (r_read == 0) {
+            external_ipv4_addr = response.pnu.publicaddress.addr;
+            return true;
+        } else if (r_read == NATPMP_ERR_NOGATEWAYSUPPORT) {
+            LogPrintf("natpmp: The gateway does not support NAT-PMP.\n");
+        } else {
+            LogPrintf("natpmp: readnatpmpresponseorretry() for public address failed with %d error.\n", r_read);
+        }
+    } else {
+        LogPrintf("natpmp: sendpublicaddressrequest() failed with %d error.\n", r_send);
+    }
+
+    return false;
+}
+
+static bool NatpmpMapping(natpmp_t* natpmp, const struct in_addr& external_ipv4_addr, uint16_t private_port, bool& external_ip_discovered)
+{
+    const uint16_t suggested_external_port = g_mapport_external_port ? g_mapport_external_port : private_port;
+    const int r_send = sendnewportmappingrequest(natpmp, NATPMP_PROTOCOL_TCP, private_port, suggested_external_port, 3600 /*seconds*/);
+    if (r_send == 12 /* OK */) {
+        int r_read;
+        natpmpresp_t response;
+        do {
+            r_read = readnatpmpresponseorretry(natpmp, &response);
+        } while (r_read == NATPMP_TRYAGAIN);
+
+        if (r_read == 0) {
+            auto pm = response.pnu.newportmapping;
+            if (private_port == pm.privateport && pm.lifetime > 0) {
+                g_mapport_external_port = pm.mappedpublicport;
+                const CService external{external_ipv4_addr, pm.mappedpublicport};
+                if (!external_ip_discovered && fDiscover) {
+                    AddLocal(external, LOCAL_MAPPED);
+                    external_ip_discovered = true;
+                }
+                LogPrintf("natpmp: Port mapping successful. External address = %s\n", external.ToString());
+                return true;
+            } else {
+                LogPrintf("natpmp: Port mapping failed.\n");
+            }
+        } else if (r_read == NATPMP_ERR_NOGATEWAYSUPPORT) {
+            LogPrintf("natpmp: The gateway does not support NAT-PMP.\n");
+        } else {
+            LogPrintf("natpmp: readnatpmpresponseorretry() for port mapping failed with %d error.\n", r_read);
+        }
+    } else {
+        LogPrintf("natpmp: sendnewportmappingrequest() failed with %d error.\n", r_send);
+    }
+
+    return false;
+}
+
+static bool ProcessNatpmp()
+{
+    bool ret = false;
+    natpmp_t natpmp;
+    struct in_addr external_ipv4_addr;
+    if (NatpmpInit(&natpmp) && NatpmpDiscover(&natpmp, external_ipv4_addr)) {
+        bool external_ip_discovered = false;
+        const uint16_t private_port = GetListenPort();
+        do {
+            ret = NatpmpMapping(&natpmp, external_ipv4_addr, private_port, external_ip_discovered);
+        } while (ret && g_mapport_interrupt.sleep_for(PORT_MAPPING_REANNOUNCE_PERIOD));
+        g_mapport_interrupt.reset();
+
+        const int r_send = sendnewportmappingrequest(&natpmp, NATPMP_PROTOCOL_TCP, private_port, g_mapport_external_port, /* remove a port mapping */ 0);
+        g_mapport_external_port = 0;
+        if (r_send == 12 /* OK */) {
+            LogPrintf("natpmp: Port mapping removed successfully.\n");
+        } else {
+            LogPrintf("natpmp: sendnewportmappingrequest(0) failed with %d error.\n", r_send);
+        }
+    }
+
+    closenatpmp(&natpmp);
+    return ret;
+}
+#endif // USE_NATPMP
+
+#ifdef USE_UPNP
+static bool ProcessUpnp()
+{
+    bool ret = false;
+    std::string port = strprintf("%u", GetListenPort());
+    const char * multicastif = nullptr;
+    const char * minissdpdpath = nullptr;
+    struct UPNPDev * devlist = nullptr;
+    char lanaddr[64];
+
+    int error = 0;
+#if MINIUPNPC_API_VERSION < 14
+    devlist = upnpDiscover(2000, multicastif, minissdpdpath, 0, 0, &error);
+#else
+    devlist = upnpDiscover(2000, multicastif, minissdpdpath, 0, 0, 2, &error);
+#endif
+
+    struct UPNPUrls urls;
+    struct IGDdatas data;
+    int r;
+
+    r = UPNP_GetValidIGD(devlist, &urls, &data, lanaddr, sizeof(lanaddr));
+    if (r == 1)
+    {
+        if (fDiscover) {
+            char externalIPAddress[40];
+            r = UPNP_GetExternalIPAddress(urls.controlURL, data.first.servicetype, externalIPAddress);
+            if (r != UPNPCOMMAND_SUCCESS) {
+                LogPrintf("UPnP: GetExternalIPAddress() returned %d\n", r);
+            } else {
+                if (externalIPAddress[0]) {
+                    CNetAddr resolved;
+                    if (LookupHost(externalIPAddress, resolved, false)) {
+                        LogPrintf("UPnP: ExternalIPAddress = %s\n", resolved.ToString());
+                        AddLocal(resolved, LOCAL_MAPPED);
+                    }
+                } else {
+                    LogPrintf("UPnP: GetExternalIPAddress failed.\n");
+                }
+            }
+        }
+
+        std::string strDesc = PACKAGE_NAME " " + FormatFullVersion();
+
+        do {
+            r = UPNP_AddPortMapping(urls.controlURL, data.first.servicetype, port.c_str(), port.c_str(), lanaddr, strDesc.c_str(), "TCP", 0, "0");
+
+            if (r != UPNPCOMMAND_SUCCESS) {
+                ret = false;
+                LogPrintf("AddPortMapping(%s, %s, %s) failed with code %d (%s)\n", port, port, lanaddr, r, strupnperror(r));
+                break;
+            } else {
+                ret = true;
+                LogPrintf("UPnP Port Mapping successful.\n");
+            }
+        } while (g_mapport_interrupt.sleep_for(PORT_MAPPING_REANNOUNCE_PERIOD));
+        g_mapport_interrupt.reset();
+
+        r = UPNP_DeletePortMapping(urls.controlURL, data.first.servicetype, port.c_str(), "TCP", 0);
+        LogPrintf("UPNP_DeletePortMapping() returned: %d\n", r);
+        freeUPNPDevlist(devlist); devlist = nullptr;
+        FreeUPNPUrls(&urls);
+    } else {
+        LogPrintf("No valid UPnP IGDs found\n");
+        freeUPNPDevlist(devlist); devlist = nullptr;
+        if (r != 0)
+            FreeUPNPUrls(&urls);
+    }
+
+    return ret;
+}
+#endif // USE_UPNP
+
+static void ThreadMapPort()
+{
+    bool ok;
+    do {
+        ok = false;
+
+#ifdef USE_UPNP
+        // High priority protocol.
+        if (g_mapport_enabled_protos & MapPortProtoFlag::UPNP) {
+            g_mapport_current_proto = MapPortProtoFlag::UPNP;
+            ok = ProcessUpnp();
+            if (ok) continue;
+        }
+#endif // USE_UPNP
+
+#ifdef USE_NATPMP
+        // Low priority protocol.
+        if (g_mapport_enabled_protos & MapPortProtoFlag::NAT_PMP) {
+            g_mapport_current_proto = MapPortProtoFlag::NAT_PMP;
+            ok = ProcessNatpmp();
+            if (ok) continue;
+        }
+#endif // USE_NATPMP
+
+        g_mapport_current_proto = MapPortProtoFlag::NONE;
+        if (g_mapport_enabled_protos == MapPortProtoFlag::NONE) {
+            return;
+        }
+
+    } while (ok || g_mapport_interrupt.sleep_for(PORT_MAPPING_RETRY_PERIOD));
+}
+
+void StartThreadMapPort()
+{
+    if (!g_mapport_thread.joinable()) {
+        assert(!g_mapport_interrupt);
+        g_mapport_thread = std::thread(std::bind(&TraceThread<void (*)()>, "mapport", &ThreadMapPort));
+    }
+}
+
+static void DispatchMapPort()
+{
+    if (g_mapport_current_proto == MapPortProtoFlag::NONE && g_mapport_enabled_protos == MapPortProtoFlag::NONE) {
+        return;
+    }
+
+    if (g_mapport_current_proto == MapPortProtoFlag::NONE && g_mapport_enabled_protos != MapPortProtoFlag::NONE) {
+        StartThreadMapPort();
+        return;
+    }
+
+    if (g_mapport_current_proto != MapPortProtoFlag::NONE && g_mapport_enabled_protos == MapPortProtoFlag::NONE) {
+        InterruptMapPort();
+        StopMapPort();
+        return;
+    }
+
+    if (g_mapport_enabled_protos & g_mapport_current_proto) {
+        // Enabling another protocol does not cause switching from the currently used one.
+        return;
+    }
+
+    assert(g_mapport_thread.joinable());
+    assert(!g_mapport_interrupt);
+    // Interrupt a protocol-specific loop in the ThreadUpnp() or in the ThreadNatpmp()
+    // to force trying the next protocol in the ThreadMapPort() loop.
+    g_mapport_interrupt();
+}
+
+static void MapPortProtoSetEnabled(MapPortProtoFlag proto, bool enabled)
+{
+    if (enabled) {
+        g_mapport_enabled_protos |= proto;
+    } else {
+        g_mapport_enabled_protos &= ~proto;
+    }
+}
+
+void StartMapPort(bool use_upnp, bool use_natpmp)
+{
+    MapPortProtoSetEnabled(MapPortProtoFlag::UPNP, use_upnp);
+    MapPortProtoSetEnabled(MapPortProtoFlag::NAT_PMP, use_natpmp);
+    DispatchMapPort();
+}
+
+void InterruptMapPort()
+{
+    g_mapport_enabled_protos = MapPortProtoFlag::NONE;
+    if (g_mapport_thread.joinable()) {
+        g_mapport_interrupt();
+    }
+}
+
+void StopMapPort()
+{
+    if (g_mapport_thread.joinable()) {
+        g_mapport_thread.join();
+        g_mapport_interrupt.reset();
+    }
+}
+
+#else  // #if defined(USE_NATPMP) || defined(USE_UPNP)
+void StartMapPort(bool use_upnp, bool use_natpmp)
+{
+    // Intentionally left blank.
+}
+void InterruptMapPort()
+{
+    // Intentionally left blank.
+}
+void StopMapPort()
+{
+    // Intentionally left blank.
+}
+#endif // #if defined(USE_NATPMP) || defined(USE_UPNP)