htc: implement socket driver (socket api not really impl'd yet)

libraries/libstratosphere/include/stratosphere/socket.hpp

@@ -18,5 +18,9 @@
 #include <netdb.h>
 #include <netinet/in.h>
 #include <stratosphere/socket/socket_types.hpp>
+#include <stratosphere/socket/socket_options.hpp>
 #include <stratosphere/socket/socket_errno.hpp>
+#include <stratosphere/socket/socket_constants.hpp>
+#include <stratosphere/socket/socket_config.hpp>
+#include <stratosphere/socket/socket_system_config.hpp>
 #include <stratosphere/socket/socket_api.hpp>

libraries/libstratosphere/include/stratosphere/socket/socket_api.hpp

@@ -16,7 +16,9 @@
 #pragma once
 #include <vapours.hpp>
 #include <stratosphere/socket/socket_types.hpp>
+#include <stratosphere/socket/socket_options.hpp>
 #include <stratosphere/socket/socket_errno.hpp>
+#include <stratosphere/socket/socket_config.hpp>
 
 namespace ams::socket {
 
@@ -28,4 +30,30 @@ namespace ams::socket {
     u32 InetNtohl(u32 net);
     u16 InetNtohs(u16 net);
 
+    Result Initialize(const Config &config);
+    Result Finalize();
+
+    Result InitializeAllocatorForInternal(void *buffer, size_t size);
+
+    ssize_t RecvFrom(s32 desc, void *buffer, size_t buffer_size, MsgFlag flags, SockAddr *out_address, SockLenT *out_addr_len);
+    ssize_t Recv(s32 desc, void *buffer, size_t buffer_size, MsgFlag flags);
+
+    ssize_t SendTo(s32 desc, const void *buffer, size_t buffer_size, MsgFlag flags, const SockAddr *address, SockLenT len);
+    ssize_t Send(s32 desc, const void *buffer, size_t buffer_size, MsgFlag flags);
+
+    s32 Shutdown(s32 desc, ShutdownMethod how);
+
+    s32 SocketExempt(Family domain, Type type, Protocol protocol);
+
+    s32 Accept(s32 desc, SockAddr *out_address, SockLenT *out_addr_len);
+    s32 Bind(s32 desc, const SockAddr *address, SockLenT len);
+
+    s32 GetSockName(s32 desc, SockAddr *out_address, SockLenT *out_addr_len);
+    s32 SetSockOpt(s32 desc, Level level, Option option_name, const void *option_value, SockLenT option_size);
+
+    s32 Listen(s32 desc, s32 backlog);
+
+    s32 Close(s32 desc);
+
+
 }

libraries/libstratosphere/include/stratosphere/socket/socket_config.hpp

@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/>.
+ */
+#pragma once
+#include <vapours.hpp>
+#include <stratosphere/os.hpp>
+#include <stratosphere/socket/socket_constants.hpp>
+
+namespace ams::socket {
+
+    constexpr ALWAYS_INLINE size_t AlignMss(size_t size) {
+        return util::DivideUp(size, static_cast<size_t>(1500));
+    }
+
+    class Config {
+        private:
+            u32 m_version;
+        protected:
+            bool m_system;
+            bool m_smbp;
+            void *m_memory_pool;
+            size_t m_memory_pool_size;
+            size_t m_allocator_pool_size;
+            size_t m_tcp_initial_send_buffer_size;
+            size_t m_tcp_initial_receive_buffer_size;
+            size_t m_tcp_auto_send_buffer_size_max;
+            size_t m_tcp_auto_receive_buffer_size_max;
+            size_t m_udp_send_buffer_size;
+            size_t m_udp_receive_buffer_size;
+            int m_sb_efficiency;
+            int m_concurrency_count_max;
+        public:
+            constexpr Config(void *mp, size_t mp_sz, size_t ap, size_t is, size_t ir, size_t as, size_t ar, size_t us, size_t ur, int sbe, int c)
+                : m_version(LibraryVersion),
+                  m_system(false),
+                  m_smbp(false),
+                  m_memory_pool(mp),
+                  m_memory_pool_size(mp_sz),
+                  m_allocator_pool_size(ap),
+                  m_tcp_initial_send_buffer_size(is),
+                  m_tcp_initial_receive_buffer_size(ir),
+                  m_tcp_auto_send_buffer_size_max(as),
+                  m_tcp_auto_receive_buffer_size_max(ar),
+                  m_udp_send_buffer_size(us),
+                  m_udp_receive_buffer_size(ur),
+                  m_sb_efficiency(sbe),
+                  m_concurrency_count_max(c)
+            {
+                /* ... */
+            }
+
+            constexpr u32 GetVersion() const { return m_version; }
+            constexpr bool IsSystemClient() const { return m_system; }
+            constexpr bool IsSmbpClient() const { return m_smbp; }
+            constexpr void *GetMemoryPool() const { return m_memory_pool; }
+            constexpr size_t GetMemoryPoolSize() const { return m_memory_pool_size; }
+            constexpr size_t GetAllocatorPoolSize() const { return m_allocator_pool_size; }
+            constexpr size_t GetTcpInitialSendBufferSize() const { return m_tcp_initial_send_buffer_size; }
+            constexpr size_t GetTcpInitialReceiveBufferSize() const { return m_tcp_initial_receive_buffer_size; }
+            constexpr size_t GetTcpAutoSendBufferSizeMax() const { return m_tcp_auto_send_buffer_size_max; }
+            constexpr size_t GetTcpAutoReceiveBufferSizeMax() const { return m_tcp_auto_receive_buffer_size_max; }
+            constexpr size_t GetUdpSendBufferSize() const { return m_udp_send_buffer_size; }
+            constexpr size_t GetUdpReceiveBufferSize() const { return m_udp_receive_buffer_size; }
+            constexpr int GetSocketBufferEfficiency() const { return m_sb_efficiency; }
+            constexpr int GetConcurrencyCountMax() const { return m_concurrency_count_max; }
+
+            constexpr void SetTcpInitialSendBufferSize(size_t size) { m_tcp_initial_send_buffer_size = size; }
+            constexpr void SetTcpInitialReceiveBufferSize(size_t size) { m_tcp_initial_receive_buffer_size = size; }
+            constexpr void SetTcpAutoSendBufferSizeMax(size_t size) { m_tcp_auto_send_buffer_size_max = size; }
+            constexpr void SetTcpAutoReceiveBufferSizeMax(size_t size) { m_tcp_auto_receive_buffer_size_max = size; }
+            constexpr void SetUdpSendBufferSize(size_t size) { m_udp_send_buffer_size = size; }
+            constexpr void SetUdpReceiveBufferSize(size_t size) { m_udp_receive_buffer_size = size; }
+            constexpr void SetSocketBufferEfficiency(int sb) { AMS_ABORT_UNLESS(1 <= sb && sb <= 8); m_sb_efficiency = sb; }
+            constexpr void SetConcurrencyCountMax(int c) { m_concurrency_count_max = c; }
+    };
+
+}

libraries/libstratosphere/include/stratosphere/socket/socket_constants.hpp

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/>.
+ */
+#pragma once
+#include <vapours.hpp>
+
+namespace ams::socket {
+
+    constexpr inline s32 InvalidSocket = -1;
+    constexpr inline s32 SocketError   = -1;
+
+    constexpr inline auto DefaultTcpAutoBufferSizeMax      = 192_KB;
+    constexpr inline auto MinTransferMemorySize            = (2 * DefaultTcpAutoBufferSizeMax + 128_KB);
+    constexpr inline auto MinSocketAllocatorSize           = 128_KB;
+    constexpr inline auto MinSocketMemoryPoolSize          = MinSocketAllocatorSize + MinTransferMemorySize;
+    constexpr inline auto MinMemHeapAllocatorSize          = 16_KB;
+    constexpr inline auto MinimumSharedMbufPoolReservation = 4_KB;
+
+    constexpr inline size_t MemoryPoolAlignment            = 4_KB;
+
+    constexpr inline auto ConcurrencyLimitMax = 14;
+
+    /* TODO: Does this need to be 1 for sockets to work on lower firmware versions? */
+    /* Is this value actually used/checked by bsdsockets sysmodule? */
+    constexpr inline auto LibraryVersion = 7;
+
+}

libraries/libstratosphere/include/stratosphere/socket/socket_errno.hpp

@@ -21,8 +21,19 @@ namespace ams::socket {
     enum class Errno : u32 {
         ESuccess   =   0,
         /* ... */
+        EAgain     =  11,
+        ENoMem     =  12,
+        /* ... */
+        EFault     =  14,
+        /* ... */
+        EInval     =  22,
+        /* ... */
         ENoSpc     =  28,
         /* ... */
+        EL3Hlt     =  46,
+        /* ... */
+        EOpNotSupp =  95,
+        ENotSup    =  EOpNotSupp,
     };
 
     enum class HErrno : s32 {

libraries/libstratosphere/include/stratosphere/socket/socket_options.hpp

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/>.
+ */
+#pragma once
+#include <vapours.hpp>
+
+namespace ams::socket {
+
+    enum class Level : s32 {
+        Sol_Ip      =   0,
+        Sol_Icmp    =   1,
+        Sol_Tcp     =   6,
+        Sol_Udp     =  17,
+        Sol_UdpLite = 136,
+
+        Sol_Socket  = 0xFFFF,
+    };
+
+    enum class Option : u32 {
+        So_Debug     = (1 <<  0),
+        /* ... */
+        So_ReuseAddr = (1 <<  2),
+        /* ... */
+    };
+
+}

libraries/libstratosphere/include/stratosphere/socket/socket_system_config.hpp

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/>.
+ */
+#pragma once
+#include <vapours.hpp>
+#include <stratosphere/socket/socket_config.hpp>
+
+namespace ams::socket {
+
+    class SystemConfigDefault : public Config {
+        public:
+            static constexpr size_t DefaultTcpInitialSendBufferSize     = 32_KB;
+            static constexpr size_t DefaultTcpInitialReceiveBufferSize  = 64_KB;
+            static constexpr size_t DefaultTcpAutoSendBufferSizeMax     = 256_KB;
+            static constexpr size_t DefaultTcpAutoReceiveBufferSizeMax  = 256_KB;
+            static constexpr size_t DefaultUdpSendBufferSize            = 9_KB;
+            static constexpr size_t DefaultUdpReceiveBufferSize         = 42240;
+            static constexpr auto   DefaultSocketBufferEfficiency       = 2;
+            static constexpr auto   DefaultConcurrency                  = 8;
+            static constexpr size_t DefaultAllocatorPoolSize            = 128_KB;
+
+            static constexpr size_t PerTcpSocketWorstCaseMemoryPoolSize = [] {
+                constexpr size_t WorstCaseTcpSendBufferSize    = AlignMss(std::max(DefaultTcpInitialSendBufferSize, DefaultTcpAutoSendBufferSizeMax));
+                constexpr size_t WorstCaseTcpReceiveBufferSize = AlignMss(std::max(DefaultTcpInitialReceiveBufferSize, DefaultTcpAutoReceiveBufferSizeMax));
+
+                return util::AlignUp(WorstCaseTcpSendBufferSize * DefaultSocketBufferEfficiency + WorstCaseTcpReceiveBufferSize * DefaultSocketBufferEfficiency, os::MemoryPageSize);
+            }();
+
+            static constexpr size_t PerUdpSocketWorstCaseMemoryPoolSize = [] {
+                constexpr size_t WorstCaseUdpSendBufferSize    = AlignMss(DefaultUdpSendBufferSize);
+                constexpr size_t WorstCaseUdpReceiveBufferSize = AlignMss(DefaultUdpReceiveBufferSize);
+
+                return util::AlignUp(WorstCaseUdpSendBufferSize * DefaultSocketBufferEfficiency + WorstCaseUdpReceiveBufferSize * DefaultSocketBufferEfficiency, os::MemoryPageSize);
+            }();
+        public:
+            constexpr SystemConfigDefault(void *mp, size_t mp_sz, size_t ap, int c=DefaultConcurrency)
+                : Config(mp, mp_sz, ap,
+                         DefaultTcpInitialSendBufferSize, DefaultTcpInitialReceiveBufferSize,
+                         DefaultTcpAutoSendBufferSizeMax, DefaultTcpAutoReceiveBufferSizeMax,
+                         DefaultUdpSendBufferSize, DefaultUdpReceiveBufferSize,
+                         DefaultSocketBufferEfficiency, c)
+            {
+                /* Mark as system. */
+                m_system = true;
+            }
+    };
+
+}

libraries/libstratosphere/include/stratosphere/socket/socket_types.hpp

@@ -79,6 +79,19 @@ namespace ams::socket {
         Pf_Max    = Af_Max
     };
 
+    enum class MsgFlag : s32 {
+        MsgFlag_None    = (0 << 0),
+        /* ... */
+        MsgFlag_WaitAll = (1 << 6),
+        /* ... */
+    };
+
+    enum class ShutdownMethod : u32 {
+        Shut_Rd   = 0,
+        Shut_Wr   = 1,
+        Shut_RdWr = 2,
+    };
+
     struct HostEnt {
         char *h_name;
         char **h_aliases;

libraries/libstratosphere/source/htclow/ctrl/htclow_ctrl_settings_holder.hpp

@@ -20,12 +20,12 @@ namespace ams::htclow::ctrl {
 
     class SettingsHolder {
         private:
-            char m_hardware_type[0x40];
+            char m_hardware_type[0x40]{};
-            char m_target_name[0x40];
+            char m_target_name[0x40]{};
-            char m_serial_number[0x40];
+            char m_serial_number[0x40]{};
-            char m_firmware_version[0x40];
+            char m_firmware_version[0x40]{};
         public:
-            SettingsHolder() { /* ... */ }
+            constexpr SettingsHolder() = default;
 
             void LoadSettings();
 

libraries/libstratosphere/source/htclow/driver/htclow_driver_manager.cpp

@@ -32,10 +32,9 @@ namespace ams::htclow::driver {
                 m_open_driver = m_debug_driver;
                 break;
             case impl::DriverType::Socket:
-                //m_socket_driver.Open();
+                m_socket_driver.Open();
-                //m_open_driver = std::addressof(m_socket_driver);
+                m_open_driver = std::addressof(m_socket_driver);
-                //break;
+                break;
-                return htclow::ResultUnknownDriverType();
             case impl::DriverType::Usb:
                 m_usb_driver.Open();
                 m_open_driver = std::addressof(m_usb_driver);

libraries/libstratosphere/source/htclow/driver/htclow_driver_manager.hpp

@@ -16,6 +16,7 @@
 #pragma once
 #include <stratosphere.hpp>
 #include "htclow_i_driver.hpp"
+#include "htclow_socket_driver.hpp"
 #include "htclow_usb_driver.hpp"
 
 namespace ams::htclow::driver {
@@ -23,14 +24,14 @@ namespace ams::htclow::driver {
     class DriverManager {
         private:
             std::optional<htclow::impl::DriverType> m_driver_type{};
-            IDriver *m_debug_driver;
+            IDriver *m_debug_driver{};
-            /* TODO: SocketDriver m_socket_driver; */
+            SocketDriver m_socket_driver;
             UsbDriver m_usb_driver{};
             /* TODO: PlainChannelDriver m_plain_channel_driver; */
             os::SdkMutex m_mutex{};
             IDriver *m_open_driver{};
         public:
-            DriverManager() = default;
+            DriverManager(mem::StandardAllocator *allocator) : m_socket_driver(allocator) { /* ... */ }
 
             Result OpenDriver(impl::DriverType driver_type);
             void CloseDriver();

libraries/libstratosphere/source/htclow/driver/htclow_driver_memory_management.cpp

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 <stratosphere.hpp>
+#include "htclow_driver_memory_management.hpp"
+
+namespace ams::htclow::driver {
+
+    namespace {
+
+        constexpr inline size_t RequiredAlignment = std::max(os::ThreadStackAlignment, os::MemoryPageSize);
+
+        using SocketConfigType = socket::SystemConfigDefault;
+
+        /* TODO: If we ever use resolvers, increase this. */
+        constexpr inline size_t SocketAllocatorSize  = 4_KB;
+        constexpr inline size_t SocketMemoryPoolSize = util::AlignUp(SocketConfigType::PerTcpSocketWorstCaseMemoryPoolSize + SocketConfigType::PerUdpSocketWorstCaseMemoryPoolSize, os::MemoryPageSize);
+
+        constexpr inline size_t SocketRequiredSize   = util::AlignUp(SocketMemoryPoolSize + SocketAllocatorSize, os::MemoryPageSize);
+        constexpr inline size_t UsbRequiredSize      = 2 * UsbDmaBufferSize + UsbIndicationThreadStackSize;
+        static_assert(util::IsAligned(UsbDmaBufferSize, RequiredAlignment));
+
+        constexpr inline size_t RequiredSize = std::max(SocketRequiredSize, UsbRequiredSize);
+        static_assert(util::IsAligned(RequiredSize, os::MemoryPageSize));
+
+        /* Declare the memory pool. */
+        alignas(RequiredAlignment) constinit u8 g_driver_memory[RequiredSize];
+
+        constexpr inline const socket::SystemConfigDefault SocketConfig(g_driver_memory, RequiredSize, SocketAllocatorSize);
+
+    }
+
+    void *GetUsbReceiveBuffer() {
+        return g_driver_memory;
+    }
+
+    void *GetUsbSendBuffer() {
+        return g_driver_memory + UsbDmaBufferSize;
+    }
+
+    void *GetUsbIndicationThreadStack() {
+        return g_driver_memory + 2 * UsbDmaBufferSize;
+    }
+
+    void InitializeSocketApiForSocketDriver() {
+        R_ABORT_UNLESS(socket::Initialize(SocketConfig));
+    }
+
+}

libraries/libstratosphere/source/htclow/driver/htclow_driver_memory_management.hpp

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/>.
+ */
+#pragma once
+#include <stratosphere.hpp>
+
+namespace ams::htclow::driver {
+
+    constexpr inline size_t UsbDmaBufferSize = 0x80000;
+    constexpr inline size_t UsbIndicationThreadStackSize = 16_KB;
+
+    void *GetUsbReceiveBuffer();
+    void *GetUsbSendBuffer();
+    void *GetUsbIndicationThreadStack();
+
+}

libraries/libstratosphere/source/htclow/driver/htclow_socket_discovery_manager.cpp

@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 <stratosphere.hpp>
+#include "htclow_socket_discovery_manager.hpp"
+#include "htclow_socket_discovery_util.hpp"
+
+namespace ams::htclow::driver {
+
+    namespace {
+
+        constexpr inline u32 BeaconQueryServiceId = 0xB48F5C51;
+
+    }
+
+    void SocketDiscoveryManager::OnDriverOpen() {
+        /* Create our socket. */
+        m_socket = socket::SocketExempt(socket::Family::Af_Inet, socket::Type::Sock_Dgram, socket::Protocol::IpProto_Udp);
+        AMS_ABORT_UNLESS(m_socket != -1);
+
+        /* Mark driver open. */
+        m_driver_closed = false;
+
+        /* Create our thread. */
+        R_ABORT_UNLESS(os::CreateThread(std::addressof(m_discovery_thread), ThreadEntry, this, m_thread_stack, os::MemoryPageSize, AMS_GET_SYSTEM_THREAD_PRIORITY(htc, HtclowDiscovery)));
+
+        /* Set our thread name. */
+        os::SetThreadNamePointer(std::addressof(m_discovery_thread), AMS_GET_SYSTEM_THREAD_NAME(htc, HtclowDiscovery));
+
+        /* Start our thread. */
+        os::StartThread(std::addressof(m_discovery_thread));
+    }
+
+    void SocketDiscoveryManager::OnDriverClose() {
+        /* Mark driver closed. */
+        m_driver_closed = true;
+
+        /* Shutdown our socket. */
+        socket::Shutdown(m_socket, socket::ShutdownMethod::Shut_RdWr);
+
+        /* Close our socket. */
+        socket::Close(m_socket);
+
+        /* Destroy our thread. */
+        os::WaitThread(std::addressof(m_discovery_thread));
+        os::DestroyThread(std::addressof(m_discovery_thread));
+    }
+
+    void SocketDiscoveryManager::OnSocketAcceptBegin(u16 port) {
+        /* ... */
+    }
+
+    void SocketDiscoveryManager::OnSocketAcceptEnd() {
+        /* ... */
+    }
+
+    void SocketDiscoveryManager::ThreadFunc() {
+        for (this->DoDiscovery(); !m_driver_closed; this->DoDiscovery()) {
+            /* Check if the driver is closed five times. */
+            for (size_t i = 0; i < 5; ++i) {
+                os::SleepThread(TimeSpan::FromSeconds(1));
+                if (m_driver_closed) {
+                    return;
+                }
+            }
+        }
+    }
+
+    Result SocketDiscoveryManager::DoDiscovery() {
+        /* Ensure we close our socket if we fail. */
+        auto socket_guard = SCOPE_GUARD { socket::Close(m_socket); };
+
+        /* Create sockaddr for our socket. */
+        const socket::SockAddrIn sockaddr = {
+            .sin_len    = 0,
+            .sin_family = socket::Family::Af_Inet,
+            .sin_port   = socket::InetHtons(20181),
+            .sin_addr   = { socket::InetHtonl(0) },
+        };
+
+        /* Bind our socket. */
+        const auto bind_res = socket::Bind(m_socket, reinterpret_cast<const socket::SockAddr *>(std::addressof(sockaddr)), sizeof(sockaddr));
+        R_UNLESS(bind_res != 0, htclow::ResultSocketBindError());
+
+        /* Loop processing beacon queries. */
+        while (true) {
+            /* Receive a tmipc query header. */
+            TmipcHeader header;
+            socket::SockAddr recv_sockaddr;
+            socket::SockLenT recv_sockaddr_len = sizeof(recv_sockaddr);
+            const auto recv_res = socket::RecvFrom(m_socket, std::addressof(header), sizeof(header), socket::MsgFlag::MsgFlag_None, std::addressof(recv_sockaddr), std::addressof(recv_sockaddr_len));
+
+            /* Check that our receive was valid. */
+            R_UNLESS(recv_res >= 0,                              htclow::ResultSocketReceiveFromError());
+            R_UNLESS(recv_sockaddr_len == sizeof(recv_sockaddr), htclow::ResultSocketReceiveFromError());
+
+            /* Check we received a packet header. */
+            if (recv_res != sizeof(header)) {
+                continue;
+            }
+
+            /* Check that we received a correctly versioned BeaconQuery packet. */
+            /* NOTE: Nintendo checks this *after* the following receive, but this seems saner. */
+            if (header.version != TmipcVersion || header.service_id != BeaconQueryServiceId) {
+                continue;
+            }
+
+            /* Receive the packet body, if there is one. */
+            char packet_data[0x120];
+
+            /* NOTE: Nintendo does not check this... */
+            if (header.data_len > sizeof(packet_data)) {
+                continue;
+            }
+
+            if (header.data_len > 0) {
+                const auto body_res = socket::RecvFrom(m_socket, packet_data, header.data_len, socket::MsgFlag::MsgFlag_None, std::addressof(recv_sockaddr), std::addressof(recv_sockaddr_len));
+                R_UNLESS(body_res >= 0, htclow::ResultSocketReceiveFromError());
+                R_UNLESS(recv_sockaddr_len == sizeof(recv_sockaddr), htclow::ResultSocketReceiveFromError());
+
+                if (body_res != header.data_len) {
+                    continue;
+                }
+            }
+
+            /* Make our beacon response packet. */
+            const auto len = MakeBeaconResponsePacket(packet_data, sizeof(packet_data));
+
+            /* Send the beacon response data. */
+            const auto send_res = socket::SendTo(m_socket, packet_data, len, socket::MsgFlag::MsgFlag_None, std::addressof(recv_sockaddr), sizeof(recv_sockaddr));
+            R_UNLESS(send_res >= 0, htclow::ResultSocketSendToError());
+        }
+
+        /* This can never happen, as the above loop should be infinite, but completion logic is here for posterity. */
+        socket_guard.Cancel();
+        return ResultSuccess();
+    }
+
+}

libraries/libstratosphere/source/htclow/driver/htclow_socket_discovery_manager.hpp

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/>.
+ */
+#pragma once
+#include <stratosphere.hpp>
+
+namespace ams::htclow::driver {
+
+    class SocketDiscoveryManager {
+        private:
+            bool m_driver_closed;
+            mem::StandardAllocator *m_allocator;
+            void *m_thread_stack;
+            os::ThreadType m_discovery_thread;
+            s32 m_socket;
+        public:
+            SocketDiscoveryManager(mem::StandardAllocator *allocator)
+                : m_driver_closed(false), m_allocator(allocator), m_thread_stack(allocator->Allocate(os::MemoryPageSize, os::ThreadStackAlignment))
+            {
+                /* ... */
+            }
+        private:
+            static void ThreadEntry(void *arg) {
+                static_cast<SocketDiscoveryManager *>(arg)->ThreadFunc();
+            }
+
+            void ThreadFunc();
+
+            Result DoDiscovery();
+        public:
+            void OnDriverOpen();
+            void OnDriverClose();
+            void OnSocketAcceptBegin(u16 port);
+            void OnSocketAcceptEnd();
+    };
+
+}

libraries/libstratosphere/source/htclow/driver/htclow_socket_discovery_util.cpp

@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 <stratosphere.hpp>
+#include "htclow_socket_discovery_util.hpp"
+#include "../ctrl/htclow_ctrl_settings_holder.hpp"
+
+namespace ams::htclow::driver {
+
+    namespace {
+
+        constexpr inline u32 AutoConnectIpv4RequestServiceId = 0x834C775A;
+        constexpr inline u32 BeaconResponseServiceId         = 0xA6F7FA96;
+
+        constexpr const char MakeAutoConnectIpv4RequestPacketFormat[] =
+          "{\r\n"
+          "  \"Address\" : \"%u.%u.%u.%u\",\r\n"
+          "  \"Port\" : %u,\r\n"
+          "  \"HW\" : \"%s\",\r\n"
+          "  \"SN\" : \"%s\"\r\n"
+          "}\r\n";
+
+        constexpr const char BeaconResponsePacketFormat[] =
+          "{\r\n"
+          "  \"Gen\" : 2,\r\n"
+          "  \"Spec \": \"%s\",\r\n"
+          "  \"MAC\" : \"00:00:00:00:00:00\",\r\n"
+          "  \"Conn\" : \"TCP\",\r\n"
+          "  \"HW\" : \"%s\",\r\n"
+          "  \"Name\" : \"%s\",\r\n"
+          "  \"SN\" : \"%s\",\r\n"
+          "  \"FW\" : \"%s\"\r\n"
+          "}\r\n";
+
+        constinit os::SdkMutex g_settings_holder_mutex;
+        constinit bool g_settings_holder_initialized = false;
+        constinit htclow::ctrl::SettingsHolder g_settings_holder;
+
+        void InitializeSettingsHolder() {
+            std::scoped_lock lk(g_settings_holder_mutex);
+
+            if (!g_settings_holder_initialized) {
+                g_settings_holder.LoadSettings();
+                g_settings_holder_initialized = true;
+            }
+        }
+
+    }
+
+    s32 MakeAutoConnectIpv4RequestPacket(char *dst, size_t dst_size, const socket::SockAddrIn &sockaddr) {
+        /* Initialize the settings holder. */
+        InitializeSettingsHolder();
+
+        /* Create the packet header. */
+        TmipcHeader header = {
+            .service_id = AutoConnectIpv4RequestServiceId,
+            .version    = TmipcVersion,
+        };
+
+        /* Create the packet body. */
+        std::scoped_lock lk(g_settings_holder_mutex);
+        const auto addr = sockaddr.sin_addr.s_addr;
+
+        char packet_body[0x100];
+        const auto ideal_len = util::SNPrintf(packet_body, sizeof(packet_body), MakeAutoConnectIpv4RequestPacketFormat,
+                                              (addr >> 0) & 0xFF, (addr >> 8) & 0xFF, (addr >> 16) & 0xFF, (addr >> 24) & 0xFF,
+                                              socket::InetNtohs(sockaddr.sin_port),
+                                              g_settings_holder.GetHardwareType(),
+                                              "" /* Nintendo passes empty string as serial number here. */
+                                              );
+
+        /* Determine actual usable body length. */
+        header.data_len = std::max<u32>(ideal_len, sizeof(packet_body));
+
+        /* Check that the packet will fit. */
+        AMS_ABORT_UNLESS(sizeof(header) + header.data_len <= dst_size);
+
+        /* Copy the formatted header. */
+        std::memcpy(dst, std::addressof(header), sizeof(header));
+        std::memcpy(dst + sizeof(header), packet_body, header.data_len);
+
+        return header.data_len;
+    }
+
+    s32 MakeBeaconResponsePacket(char *dst, size_t dst_size) {
+        /* Initialize the settings holder. */
+        InitializeSettingsHolder();
+
+        /* Create the packet header. */
+        TmipcHeader header = {
+            .service_id = BeaconResponseServiceId,
+            .version    = TmipcVersion,
+        };
+
+        /* Create the packet body. */
+        std::scoped_lock lk(g_settings_holder_mutex);
+
+        char packet_body[0x100];
+        const auto ideal_len = util::SNPrintf(packet_body, sizeof(packet_body), BeaconResponsePacketFormat,
+                                              g_settings_holder.GetSpec(),
+                                              g_settings_holder.GetHardwareType(),
+                                              g_settings_holder.GetTargetName(),
+                                              g_settings_holder.GetSerialNumber(),
+                                              g_settings_holder.GetFirmwareVersion()
+                                              );
+
+        /* Determine actual usable body length. */
+        header.data_len = std::max<u32>(ideal_len, sizeof(packet_body));
+
+        /* Check that the packet will fit. */
+        AMS_ABORT_UNLESS(sizeof(header) + header.data_len <= dst_size);
+
+        /* Copy the formatted header. */
+        std::memcpy(dst, std::addressof(header), sizeof(header));
+        std::memcpy(dst + sizeof(header), packet_body, header.data_len);
+
+        return header.data_len;
+    }
+
+}

libraries/libstratosphere/source/htclow/driver/htclow_socket_discovery_util.hpp

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/>.
+ */
+#pragma once
+#include <stratosphere.hpp>
+
+namespace ams::htclow::driver {
+
+    constexpr inline u8 TmipcVersion = 5;
+
+    struct TmipcHeader {
+        u32 service_id;
+        u32 reserved_00;
+        u16 reserved_01;
+        u8  reserved_02;
+        u8  version;
+        u32 data_len;
+        u32 reserved[4];
+    };
+    static_assert(util::is_pod<TmipcHeader>::value);
+    static_assert(sizeof(TmipcHeader) == 0x20);
+
+    s32 MakeAutoConnectIpv4RequestPacket(char *dst, size_t dst_size, const socket::SockAddrIn &sockaddr);
+    s32 MakeBeaconResponsePacket(char *dst, size_t dst_size);
+
+}

libraries/libstratosphere/source/htclow/driver/htclow_socket_driver.cpp

@@ -0,0 +1,283 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 <stratosphere.hpp>
+#include "htclow_socket_driver.hpp"
+#include "htclow_socket_discovery_util.hpp"
+
+namespace ams::htclow::driver {
+
+    Result SocketDriver::ConnectThread() {
+        /* Do auto connect, if we should. */
+        if (m_auto_connect_reserved) {
+            this->DoAutoConnect();
+        }
+
+        /* Get the socket's name. */
+        socket::SockAddrIn sockaddr;
+        socket::SockLenT sockaddr_len = sizeof(sockaddr);
+        R_UNLESS(socket::GetSockName(m_server_socket, reinterpret_cast<socket::SockAddr *>(std::addressof(sockaddr)), std::addressof(sockaddr_len)) == 0, htclow::ResultSocketGetSockNameError());
+
+        /* Accept. */
+        m_discovery_manager.OnSocketAcceptBegin(sockaddr.sin_port);
+
+        sockaddr_len = sizeof(m_server_sockaddr);
+        const auto client_desc = socket::Accept(m_server_socket, reinterpret_cast<socket::SockAddr *>(std::addressof(m_server_sockaddr)), std::addressof(sockaddr_len));
+
+        m_discovery_manager.OnSocketAcceptEnd();
+
+        /* Check accept result. */
+        R_UNLESS(client_desc >= 0, htclow::ResultSocketAcceptError());
+
+        /* Setup client socket. */
+        R_TRY(this->SetupClientSocket(client_desc));
+
+        return ResultSuccess();
+    }
+
+    Result SocketDriver::CreateServerSocket() {
+        /* Check that we don't have a server socket. */
+        AMS_ASSERT(!m_server_socket_valid);
+
+        /* Create the socket. */
+        const auto desc = socket::SocketExempt(socket::Family::Af_Inet, socket::Type::Sock_Stream, socket::Protocol::IpProto_Tcp);
+        R_UNLESS(desc != -1, htclow::ResultSocketSocketExemptError());
+
+        /* Be sure that we close the socket if we don't succeed. */
+        auto socket_guard = SCOPE_GUARD { socket::Close(desc); };
+
+        /* Create sockaddr for our socket. */
+        const socket::SockAddrIn sockaddr = {
+            .sin_len    = 0,
+            .sin_family = socket::Family::Af_Inet,
+            .sin_port   = socket::InetHtons(20180),
+            .sin_addr   = { socket::InetHtonl(0) },
+        };
+
+        /* Enable local address reuse. */
+        {
+            u32 enable = 1;
+            const auto res = socket::SetSockOpt(desc, socket::Level::Sol_Socket, socket::Option::So_ReuseAddr, std::addressof(enable), sizeof(enable));
+            AMS_ABORT_UNLESS(res == 0);
+        }
+
+        /* Bind the socket. */
+        const auto bind_res = socket::Bind(desc, reinterpret_cast<const socket::SockAddr *>(std::addressof(sockaddr)), sizeof(sockaddr));
+        R_UNLESS(bind_res == 0, htclow::ResultSocketBindError());
+
+        /* Listen on the socket. */
+        const auto listen_res = socket::Listen(desc, 1);
+        R_UNLESS(listen_res == 0, htclow::ResultSocketListenError());
+
+        /* We succeeded. */
+        socket_guard.Cancel();
+        m_server_socket       = desc;
+        m_server_socket_valid = true;
+
+        return ResultSuccess();
+    }
+
+    void SocketDriver::DestroyServerSocket() {
+        if (m_server_socket_valid) {
+            socket::Shutdown(m_server_socket, socket::ShutdownMethod::Shut_RdWr);
+            socket::Close(m_server_socket);
+            m_server_socket_valid = false;
+        }
+    }
+
+    Result SocketDriver::SetupClientSocket(s32 desc) {
+        std::scoped_lock lk(m_mutex);
+
+        /* Check that we don't have a client socket. */
+        AMS_ASSERT(!m_client_socket_valid);
+
+        /* Be sure that we close the socket if we don't succeed. */
+        auto socket_guard = SCOPE_GUARD { socket::Close(desc); };
+
+        /* Enable debug logging for the socket. */
+        u32 debug = 1;
+        const auto res = socket::SetSockOpt(desc, socket::Level::Sol_Tcp, socket::Option::So_Debug, std::addressof(debug), sizeof(debug));
+        R_UNLESS(res >= 0, htclow::ResultSocketSetSockOptError());
+
+        /* We succeeded. */
+        socket_guard.Cancel();
+        m_client_socket       = desc;
+        m_client_socket_valid = true;
+
+        return ResultSuccess();
+    }
+
+    bool SocketDriver::IsAutoConnectReserved() {
+        return m_auto_connect_reserved;
+    }
+
+    void SocketDriver::ReserveAutoConnect() {
+        std::scoped_lock lk(m_mutex);
+
+        if (m_client_socket_valid) {
+            /* Save our client sockaddr. */
+            socket::SockLenT sockaddr_len = sizeof(m_saved_client_sockaddr);
+            if (socket::GetSockName(m_server_socket, reinterpret_cast<socket::SockAddr *>(std::addressof(m_saved_client_sockaddr)), std::addressof(sockaddr_len)) != 0) {
+                return;
+            }
+
+            /* Save our server sockaddr. */
+            m_saved_server_sockaddr = m_server_sockaddr;
+
+            /* Mark auto-connect reserved. */
+            m_auto_connect_reserved = true;
+        }
+    }
+
+    void SocketDriver::DoAutoConnect() {
+        /* Clear auto-connect reserved. */
+        m_auto_connect_reserved = false;
+
+        /* Create udb socket. */
+        const auto desc = socket::SocketExempt(socket::Family::Af_Inet, socket::Type::Sock_Dgram, socket::Protocol::IpProto_Udp);
+        if (desc == -1) {
+            return;
+        }
+
+        /* Clean up the desc when we're done. */
+        ON_SCOPE_EXIT { socket::Close(desc); };
+
+        /* Create auto-connect packet. */
+        char auto_connect_packet[0x120];
+        s32 len;
+        {
+            const socket::SockAddrIn sockaddr = {
+                .sin_family = socket::Family::Af_Inet,
+                .sin_port   = m_saved_client_sockaddr.sin_port,
+                .sin_addr   = m_saved_client_sockaddr.sin_addr,
+            };
+
+            len = htclow::driver::MakeAutoConnectIpv4RequestPacket(auto_connect_packet, sizeof(auto_connect_packet), sockaddr);
+        }
+
+        /* Send the auto-connect packet to the host on port 20181. */
+        const socket::SockAddrIn sockaddr = {
+            .sin_family = socket::Family::Af_Inet,
+            .sin_port   = socket::InetHtons(20181),
+            .sin_addr   = m_saved_server_sockaddr.sin_addr,
+        };
+
+        /* Send the auto-connect packet. */
+        socket::SendTo(desc, auto_connect_packet, len, socket::MsgFlag::MsgFlag_None, reinterpret_cast<const socket::SockAddr *>(std::addressof(sockaddr)), sizeof(sockaddr));
+    }
+
+    Result SocketDriver::Open() {
+        m_discovery_manager.OnDriverOpen();
+        return ResultSuccess();
+    }
+
+    void SocketDriver::Close() {
+        m_discovery_manager.OnDriverClose();
+    }
+
+    Result SocketDriver::Connect(os::EventType *event) {
+        /* Allocate a temporary thread stack. */
+        void *stack = m_allocator->Allocate(os::MemoryPageSize, os::ThreadStackAlignment);
+        ON_SCOPE_EXIT { m_allocator->Free(stack); };
+
+        /* Try to create a server socket. */
+        R_TRY(this->CreateServerSocket());
+
+        /* Prepare to run our connect thread. */
+        m_event.Clear();
+
+        /* Run our connect thread. */
+        {
+            /* Create the thread. */
+            os::ThreadType connect_thread;
+            R_ABORT_UNLESS(os::CreateThread(std::addressof(connect_thread), ConnectThreadEntry, this, stack, os::MemoryPageSize, AMS_GET_SYSTEM_THREAD_PRIORITY(htc, HtclowTcpServer)));
+
+            /* Set the thread's name. */
+            os::SetThreadNamePointer(std::addressof(connect_thread), AMS_GET_SYSTEM_THREAD_NAME(htc, HtclowTcpServer));
+
+            /* Start the thread. */
+            os::StartThread(std::addressof(connect_thread));
+
+            /* Check if we should cancel the connection. */
+            if (os::WaitAny(event, m_event.GetBase()) == 0) {
+                this->DestroyServerSocket();
+            }
+
+            /* Wait for the connect thread to finish. */
+            os::WaitThread(std::addressof(connect_thread));
+
+            /* Destroy the connection thread. */
+            os::DestroyThread(std::addressof(connect_thread));
+
+            /* Destroy the server socket. */
+            this->DestroyServerSocket();
+        }
+
+        /* Return our connection result. */
+        return m_connect_result;
+    }
+
+    void SocketDriver::Shutdown() {
+        std::scoped_lock lk(m_mutex);
+
+        /* Shut down our client socket, if we need to. */
+        if (m_client_socket_valid) {
+            socket::Shutdown(m_client_socket, socket::ShutdownMethod::Shut_RdWr);
+            socket::Close(m_client_socket);
+            m_client_socket_valid = 0;
+        }
+    }
+
+    Result SocketDriver::Send(const void *src, int src_size) {
+        /* Check the input size. */
+        R_UNLESS(src_size >= 0, htclow::ResultInvalidArgument());
+
+        /* Repeatedly send data until it's all sent. */
+        ssize_t cur_sent;
+        for (ssize_t sent = 0; sent < src_size; sent += cur_sent) {
+            cur_sent = socket::Send(m_client_socket, static_cast<const u8 *>(src) + sent, src_size - sent, socket::MsgFlag::MsgFlag_None);
+            R_UNLESS(cur_sent > 0, htclow::ResultSocketSendError());
+        }
+
+        return ResultSuccess();
+    }
+
+    Result SocketDriver::Receive(void *dst, int dst_size) {
+        /* Check the input size. */
+        R_UNLESS(dst_size >= 0, htclow::ResultInvalidArgument());
+
+        /* Repeatedly receive data until it's all sent. */
+        ssize_t cur_recv;
+        for (ssize_t received = 0; received < dst_size; received += cur_recv) {
+            cur_recv = socket::Recv(m_client_socket, static_cast<u8 *>(dst) + received, dst_size - received, socket::MsgFlag::MsgFlag_None);
+            R_UNLESS(cur_recv > 0, htclow::ResultSocketReceiveError());
+        }
+
+        return ResultSuccess();
+    }
+
+    void SocketDriver::CancelSendReceive() {
+        this->Shutdown();
+    }
+
+    void SocketDriver::Suspend() {
+        this->ReserveAutoConnect();
+    }
+
+    void SocketDriver::Resume() {
+        /* ... */
+    }
+
+}

libraries/libstratosphere/source/htclow/driver/htclow_socket_driver.hpp

@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/>.
+ */
+#pragma once
+#include <stratosphere.hpp>
+#include "htclow_i_driver.hpp"
+#include "htclow_socket_discovery_manager.hpp"
+
+namespace ams::htclow::driver {
+
+    class SocketDriver final : public IDriver {
+        private:
+            mem::StandardAllocator *m_allocator;
+            SocketDiscoveryManager m_discovery_manager;
+            socket::SockAddrIn m_server_sockaddr;
+            socket::SockAddrIn m_saved_server_sockaddr;
+            socket::SockAddrIn m_saved_client_sockaddr;
+            os::Event m_event;
+            Result m_connect_result;
+            os::SdkMutex m_mutex;
+            s32 m_server_socket;
+            s32 m_client_socket;
+            bool m_server_socket_valid;
+            bool m_client_socket_valid;
+            bool m_auto_connect_reserved;
+        public:
+            SocketDriver(mem::StandardAllocator *allocator)
+                : m_allocator(allocator), m_discovery_manager(m_allocator), m_event(os::EventClearMode_ManualClear),
+                  m_connect_result(), m_mutex(), m_server_socket(), m_client_socket(), m_server_socket_valid(false),
+                  m_client_socket_valid(false), m_auto_connect_reserved(false)
+            {
+                /* ... */
+            }
+        private:
+            static void ConnectThreadEntry(void *arg) {
+                auto * const driver = static_cast<SocketDriver *>(arg);
+
+                driver->m_connect_result = driver->ConnectThread();
+                driver->m_event.Signal();
+            }
+
+            Result ConnectThread();
+        private:
+            Result CreateServerSocket();
+            void DestroyServerSocket();
+
+            Result SetupClientSocket(s32 desc);
+
+            bool IsAutoConnectReserved();
+            void ReserveAutoConnect();
+            void DoAutoConnect();
+        public:
+            virtual Result Open() override;
+            virtual void Close() override;
+            virtual Result Connect(os::EventType *event) override;
+            virtual void Shutdown() override;
+            virtual Result Send(const void *src, int src_size) override;
+            virtual Result Receive(void *dst, int dst_size) override;
+            virtual void CancelSendReceive() override;
+            virtual void Suspend() override;
+            virtual void Resume() override;
+    };
+
+}

libraries/libstratosphere/source/htclow/driver/htclow_usb_impl.cpp

@@ -15,6 +15,7 @@
  */
 #include <stratosphere.hpp>
 #include "htclow_usb_impl.hpp"
+#include "htclow_driver_memory_management.hpp"
 
 namespace ams::htclow::driver {
 
@@ -179,11 +180,8 @@ namespace ams::htclow::driver {
             .wBytesPerInterval  = 0x0000,
         };
 
-        constexpr size_t UsbDmaBufferSize = 0x60000;
+        constinit void *g_usb_receive_buffer = nullptr;
-
+        constinit void *g_usb_send_buffer    = nullptr;
-        alignas(os::MemoryPageSize) constinit u8 g_usb_receive_buffer[UsbDmaBufferSize];
-        alignas(os::MemoryPageSize) constinit u8 g_usb_send_buffer[UsbDmaBufferSize];
-        alignas(os::ThreadStackAlignment) constinit u8 g_usb_indication_thread_stack[16_KB];
 
         constinit UsbAvailabilityChangeCallback g_availability_change_callback = nullptr;
         constinit void *g_availability_change_param = nullptr;
@@ -346,6 +344,10 @@ namespace ams::htclow::driver {
         /* Set the interface as initialized. */
         g_usb_interface_initialized = true;
 
+        /* Get the dma buffers. */
+        g_usb_receive_buffer = GetUsbReceiveBuffer();
+        g_usb_send_buffer    = GetUsbSendBuffer();
+
         /* If we fail somewhere, finalize. */
         auto init_guard = SCOPE_GUARD { FinalizeUsbInterface(); };
 
@@ -385,7 +387,7 @@ namespace ams::htclow::driver {
         R_TRY(ConvertUsbDriverResult(InitializeDsEndpoints()));
 
         /* Create the indication thread. */
-        R_ABORT_UNLESS(os::CreateThread(std::addressof(g_usb_indication_thread), &UsbIndicationThreadFunction, nullptr, g_usb_indication_thread_stack, sizeof(g_usb_indication_thread_stack), AMS_GET_SYSTEM_THREAD_PRIORITY(htc, HtclowUsbIndication)));
+        R_ABORT_UNLESS(os::CreateThread(std::addressof(g_usb_indication_thread), &UsbIndicationThreadFunction, nullptr, GetUsbIndicationThreadStack(), UsbIndicationThreadStackSize, AMS_GET_SYSTEM_THREAD_PRIORITY(htc, HtclowUsbIndication)));
 
         /* Set the thread name. */
         os::SetThreadNamePointer(std::addressof(g_usb_indication_thread), AMS_GET_SYSTEM_THREAD_NAME(htc, HtclowUsbIndication));

libraries/libstratosphere/source/htclow/htclow_manager_impl.cpp

@@ -20,7 +20,7 @@
 namespace ams::htclow {
 
     HtclowManagerImpl::HtclowManagerImpl(mem::StandardAllocator *allocator)
-        : m_packet_factory(allocator), m_driver_manager(), m_mux(std::addressof(m_packet_factory), std::addressof(m_ctrl_state_machine)),
+        : m_packet_factory(allocator), m_driver_manager(allocator), m_mux(std::addressof(m_packet_factory), std::addressof(m_ctrl_state_machine)),
           m_ctrl_packet_factory(allocator), m_ctrl_state_machine(), m_ctrl_service(std::addressof(m_ctrl_packet_factory), std::addressof(m_ctrl_state_machine), std::addressof(m_mux)),
           m_worker(allocator, std::addressof(m_mux), std::addressof(m_ctrl_service)),
           m_listener(allocator, std::addressof(m_mux), std::addressof(m_ctrl_service), std::addressof(m_worker)),

libraries/libstratosphere/source/socket/impl/socket_allocator.hpp

@@ -18,6 +18,8 @@
 
 namespace ams::socket::impl {
 
+    constexpr inline auto MinimumHeapAlignment = 0x10;
+
     void *Alloc(size_t size);
     void *Calloc(size_t num, size_t size);
     void Free(void *ptr);

libraries/libstratosphere/source/socket/impl/socket_api.hpp

@@ -20,9 +20,19 @@ namespace ams::socket::impl {
     Errno GetLastError();
     void SetLastError(Errno err);
 
+    bool HeapIsAvailable(int generation);
+    int GetHeapGeneration();
+
     u32 InetHtonl(u32 host);
     u16 InetHtons(u16 host);
     u32 InetNtohl(u32 net);
     u16 InetNtohs(u16 net);
 
+    Result Initialize(const Config &config);
+    Result Finalize();
+
+    Result InitializeAllocatorForInternal(void *buffer, size_t size);
+
+    s32 Shutdown(s32 desc, ShutdownMethod how);
+
 }

libraries/libstratosphere/source/socket/impl/socket_api.os.horizon.cpp

@@ -17,36 +17,100 @@
 #include "socket_api.hpp"
 #include "socket_allocator.hpp"
 
+extern "C" {
+
+#include <switch/services/bsd.h>
+
+}
+
 namespace ams::socket::impl {
 
+    namespace {
+
+        constinit bool g_initialized = false;
+
+        constinit os::SdkMutex g_heap_mutex;
+
+        constinit lmem::HeapHandle g_heap_handle = nullptr;
+        constinit int g_heap_generation = -1;
+
+        ALWAYS_INLINE bool IsInitialized() {
+            return g_initialized;
+        }
+
+    }
+
     void *Alloc(size_t size) {
-        /* TODO: expheap, heap generation. */
+        std::scoped_lock lk(g_heap_mutex);
-        return ams::Malloc(size);
+
+        AMS_ASSERT(g_heap_generation > 0);
+
+        void *ptr = nullptr;
+
+        if (!g_heap_handle) {
+            socket::impl::SetLastError(Errno::EOpNotSupp);
+        } else if ((ptr = lmem::AllocateFromExpHeap(g_heap_handle, size)) == nullptr) {
+            socket::impl::SetLastError(Errno::EOpNotSupp);
+        }
+
+        return ptr;
     }
 
     void *Calloc(size_t num, size_t size) {
-        if (void *ptr = Alloc(size * num); ptr != nullptr) {
+        std::scoped_lock lk(g_heap_mutex);
-            std::memset(ptr, 0, size * num);
+
-            return ptr;
+        AMS_ASSERT(g_heap_generation > 0);
+
+        void *ptr = nullptr;
+
+        if (!g_heap_handle) {
+            socket::impl::SetLastError(Errno::EOpNotSupp);
+        } else if ((ptr = lmem::AllocateFromExpHeap(g_heap_handle, size * num)) == nullptr) {
+            socket::impl::SetLastError(Errno::EOpNotSupp);
         } else {
-            return nullptr;
+            std::memset(ptr, 0, size * num);
         }
+
+        return ptr;
     }
 
     void Free(void *ptr) {
-        /* TODO: expheap, heap generation. */
+        std::scoped_lock lk(g_heap_mutex);
-        return ams::Free(ptr);
+
+        AMS_ASSERT(g_heap_generation > 0);
+
+        if (!g_heap_handle) {
+            socket::impl::SetLastError(Errno::EOpNotSupp);
+        } else if (ptr != nullptr) {
+            lmem::FreeToExpHeap(g_heap_handle, ptr);
+        }
+    }
+
+    bool HeapIsAvailable(int generation) {
+        std::scoped_lock lk(g_heap_mutex);
+
+        return g_heap_handle && g_heap_generation == generation;
+    }
+
+    int GetHeapGeneration() {
+        std::scoped_lock lk(g_heap_mutex);
+
+        return g_heap_generation;
     }
 
     Errno GetLastError() {
-        /* TODO: check that client library is initialized. */
+        if (AMS_LIKELY(IsInitialized())) {
             return static_cast<Errno>(errno);
+        } else {
+            return Errno::EInval;
+        }
     }
 
     void SetLastError(Errno err) {
-        /* TODO: check that client library is initialized. */
+        if (AMS_LIKELY(IsInitialized())) {
             errno = static_cast<int>(err);
         }
+    }
 
     u32 InetHtonl(u32 host) {
         if constexpr (util::IsBigEndian()) {
@@ -80,4 +144,109 @@ namespace ams::socket::impl {
         }
     }
 
+    namespace {
+
+        void InitializeHeapImpl(void *buffer, size_t size) {
+            /* NOTE: Nintendo uses both CreateOption_ThreadSafe *and* a global heap mutex. */
+            /*       This is unnecessary, and using a single SdkMutex is more performant, since we're not recursive. */
+            std::scoped_lock lk(g_heap_mutex);
+
+            g_heap_handle = lmem::CreateExpHeap(buffer, size, lmem::CreateOption_None);
+        }
+
+        Result InitializeCommon(const Config &config) {
+            /* Check pre-conditions. */
+            AMS_ABORT_UNLESS(!IsInitialized());
+            AMS_ABORT_UNLESS(config.GetMemoryPool() != nullptr);
+            AMS_ABORT_UNLESS(1 <= config.GetConcurrencyCountMax() && config.GetConcurrencyCountMax() <= ConcurrencyLimitMax);
+            if (!config.IsSmbpClient()) { AMS_ABORT_UNLESS(config.GetAllocatorPoolSize() < config.GetMemoryPoolSize()); }
+            AMS_ABORT_UNLESS(util::IsAligned(config.GetMemoryPoolSize(), os::MemoryPageSize));
+            AMS_ABORT_UNLESS(util::IsAligned(config.GetAllocatorPoolSize(), os::MemoryPageSize));
+            AMS_ABORT_UNLESS(config.GetAllocatorPoolSize() >= 4_KB);
+            if (!config.IsSystemClient()) {
+                R_UNLESS(config.GetMemoryPoolSize() >= socket::MinSocketMemoryPoolSize, socket::ResultInsufficientProvidedMemory());
+            }
+
+            const size_t transfer_memory_size = config.GetMemoryPoolSize() - config.GetAllocatorPoolSize();
+            if (!config.IsSmbpClient()) {
+                R_UNLESS(transfer_memory_size >= socket::MinMemHeapAllocatorSize, socket::ResultInsufficientProvidedMemory());
+            } else {
+                R_UNLESS(config.GetMemoryPoolSize() >= socket::MinimumSharedMbufPoolReservation, socket::ResultInsufficientProvidedMemory());
+            }
+
+            /* Initialize the allocator heap. */
+            InitializeHeapImpl(static_cast<u8 *>(config.GetMemoryPool()) + transfer_memory_size, config.GetAllocatorPoolSize());
+
+            /* Initialize libnx. */
+            {
+                const ::BsdInitConfig libnx_config = {
+                    .version             = config.GetVersion(),
+                    .tmem_buffer         = config.GetMemoryPool(),
+                    .tmem_buffer_size    = transfer_memory_size,
+
+                    .tcp_tx_buf_size     = static_cast<u32>(config.GetTcpInitialSendBufferSize()),
+                    .tcp_rx_buf_size     = static_cast<u32>(config.GetTcpInitialReceiveBufferSize()),
+                    .tcp_tx_buf_max_size = static_cast<u32>(config.GetTcpAutoSendBufferSizeMax()),
+                    .tcp_rx_buf_max_size = static_cast<u32>(config.GetTcpAutoReceiveBufferSizeMax()),
+
+                    .udp_tx_buf_size     = static_cast<u32>(config.GetUdpSendBufferSize()),
+                    .udp_rx_buf_size     = static_cast<u32>(config.GetUdpReceiveBufferSize()),
+
+                    .sb_efficiency       = static_cast<u32>(config.GetSocketBufferEfficiency()),
+                };
+
+                const auto service_type = config.IsSystemClient() ? (1 << 1) : (1 << 0);
+
+                sm::DoWithSession([&] {
+                    R_ABORT_UNLESS(::bsdInitialize(std::addressof(libnx_config), static_cast<u32>(config.GetConcurrencyCountMax()), service_type));
+                });
+            }
+
+            /* Set the heap generation. */
+            g_heap_generation = (g_heap_generation + 1) % MinimumHeapAlignment;
+
+            /* TODO: socket::resolver::EnableResolverCalls()? Not necessary in our case (htc), but consider calling it. */
+
+            return ResultSuccess();
+        }
+
+    }
+
+    Result Initialize(const Config &config) {
+        return InitializeCommon(config);
+    }
+
+    Result Finalize() {
+        /* Check pre-conditions. */
+        AMS_ABORT_UNLESS(IsInitialized());
+
+        /* TODO: If we support statistics, kill the statistics thread. */
+
+        /* TODO: socket::resolver::DisableResolverCalls()? */
+
+        /* Finalize libnx. */
+        ::bsdExit();
+
+        /* Finalize the heap. */
+        lmem::HeapHandle heap_handle;
+        {
+            std::scoped_lock lk(g_heap_mutex);
+
+            heap_handle   = g_heap_handle;
+            g_heap_handle = nullptr;
+        }
+        lmem::DestroyExpHeap(heap_handle);
+
+        return ResultSuccess();
+    }
+
+    Result InitializeAllocatorForInternal(void *buffer, size_t size) {
+        /* Check pre-conditions. */
+        AMS_ABORT_UNLESS(util::IsAligned(size, os::MemoryPageSize));
+        AMS_ABORT_UNLESS(size >= 4_KB);
+
+        InitializeHeapImpl(buffer, size);
+        return ResultSuccess();
+    }
+
 }

libraries/libstratosphere/source/socket/socket_api.cpp

@@ -42,4 +42,16 @@ namespace ams::socket {
         return impl::InetNtohs(net);
     }
 
+    Result Initialize(const Config &config) {
+        return impl::Initialize(config);
+    }
+
+    Result Finalize() {
+        return impl::Finalize();
+    }
+
+    Result InitializeAllocatorForInternal(void *buffer, size_t size) {
+        return impl::InitializeAllocatorForInternal(buffer, size);
+    }
+
 }

libraries/libvapours/include/vapours/results.hpp

@@ -59,6 +59,7 @@
 #include <vapours/results/settings_results.hpp>
 #include <vapours/results/sf_results.hpp>
 #include <vapours/results/sm_results.hpp>
+#include <vapours/results/socket_results.hpp>
 #include <vapours/results/spl_results.hpp>
 #include <vapours/results/svc_results.hpp>
 #include <vapours/results/time_results.hpp>

libraries/libvapours/include/vapours/results/htclow_results.hpp

@@ -52,6 +52,18 @@ namespace ams::htclow {
         R_DEFINE_ERROR_RANGE(DriverError, 1200, 1999);
             R_DEFINE_ERROR_RESULT(DriverOpened, 1201);
 
+            R_DEFINE_ERROR_RANGE(SocketDriverError, 1300, 1399);
+                R_DEFINE_ERROR_RESULT(SocketSocketExemptError, 1301);
+                R_DEFINE_ERROR_RESULT(SocketBindError,         1302);
+                R_DEFINE_ERROR_RESULT(SocketListenError,       1304);
+                R_DEFINE_ERROR_RESULT(SocketAcceptError,       1305);
+                R_DEFINE_ERROR_RESULT(SocketReceiveError,      1306);
+                R_DEFINE_ERROR_RESULT(SocketSendError,         1307);
+                R_DEFINE_ERROR_RESULT(SocketReceiveFromError,  1308);
+                R_DEFINE_ERROR_RESULT(SocketSendToError,       1309);
+                R_DEFINE_ERROR_RESULT(SocketSetSockOptError,   1310);
+                R_DEFINE_ERROR_RESULT(SocketGetSockNameError,  1311);
+
             R_DEFINE_ERROR_RANGE(UsbDriverError, 1400, 1499);
                 R_DEFINE_ERROR_RESULT(UsbDriverUnknownError, 1401);
                 R_DEFINE_ERROR_RESULT(UsbDriverBusyError,    1402);

libraries/libvapours/include/vapours/results/socket_results.hpp

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/>.
+ */
+
+#pragma once
+#include <vapours/results/results_common.hpp>
+
+namespace ams::socket {
+
+    R_DEFINE_NAMESPACE_RESULT_MODULE(27);
+
+    R_DEFINE_ERROR_RESULT(InsufficientProvidedMemory, 1);
+
+}

stratosphere/ams_mitm/source/dns_mitm/dnsmitm_module.cpp

@@ -39,6 +39,8 @@ namespace ams::mitm::socket::resolver {
                 virtual Result OnNeedsToAccept(int port_index, Server *server) override;
         };
 
+        alignas(os::MemoryPageSize) constinit u8 g_resolver_allocator_buffer[16_KB];
+
         ServerManager g_server_manager;
 
         Result ServerManager::OnNeedsToAccept(int port_index, Server *server) {
@@ -121,6 +123,9 @@ namespace ams::mitm::socket::resolver {
             return;
         }
 
+        /* Initialize the socket allocator. */
+        ams::socket::InitializeAllocatorForInternal(g_resolver_allocator_buffer, sizeof(g_resolver_allocator_buffer));
+
         /* Initialize debug. */
         resolver::InitializeDebug(ShouldEnableDebugLog());
 

stratosphere/htc/htc.json

@@ -15,7 +15,7 @@
 	"filesystem_access":	{
 		"permissions":	"0xFFFFFFFFFFFFFFFF"
 	},
-	"service_access":	["pcie", "psc:m", "set:cal", "set:fd", "set:sys", "usb:ds", "fsp-srv"],
+	"service_access":	["pcie", "psc:m", "set:cal", "set:fd", "set:sys", "usb:ds", "fsp-srv", "bsd:s"],
 	"service_host":	["file_io", "htc", "htcs"],
 	"kernel_capabilities":	[{
 			"type":	"kernel_flags",

stratosphere/htc/source/htc_main.cpp

@@ -200,6 +200,10 @@ namespace ams::htc {
                 return htclow::impl::DriverType::HostBridge;
             } else if (std::strstr(transport, "plainchannel")) {
                 return htclow::impl::DriverType::PlainChannel;
+            } else if (std::strstr(transport, "socket")) {
+                /* NOTE: Nintendo does not actually allow socket driver to be selected. */
+                /* Should we disallow this? Undesirable, because people will want to use docked tma. */
+                return htclow::impl::DriverType::Socket;
             } else {
                 return DefaultHtclowDriverType;
             }
@@ -230,6 +234,12 @@ namespace ams::htc {
 
 }
 
+namespace ams::htclow::driver {
+
+    void InitializeSocketApiForSocketDriver();
+
+}
+
 int main(int argc, char **argv)
 {
     /* Set thread name. */
@@ -240,6 +250,11 @@ int main(int argc, char **argv)
     const auto driver_type = htc::GetHtclowDriverType();
     htclow::HtclowManagerHolder::SetDefaultDriver(driver_type);
 
+    /* If necessary, initialize the socket driver. */
+    if (driver_type == htclow::impl::DriverType::Socket) {
+        htclow::driver::InitializeSocketApiForSocketDriver();
+    }
+
     /* Initialize the htclow manager. */
     htclow::HtclowManagerHolder::AddReference();
     ON_SCOPE_EXIT { htclow::HtclowManagerHolder::Release(); };