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Diffstat (limited to 'src/OSSupport/UDPEndpointImpl.cpp')
| -rw-r--r-- | src/OSSupport/UDPEndpointImpl.cpp | 608 |
1 files changed, 608 insertions, 0 deletions
diff --git a/src/OSSupport/UDPEndpointImpl.cpp b/src/OSSupport/UDPEndpointImpl.cpp new file mode 100644 index 000000000..ece521ab8 --- /dev/null +++ b/src/OSSupport/UDPEndpointImpl.cpp @@ -0,0 +1,608 @@ + +// UDPEndpointImpl.cpp + +// Implements the cUDPEndpointImpl class representing an implementation of an endpoint in UDP communication + +#include "Globals.h" +#include "UDPEndpointImpl.h" +#include "NetworkSingleton.h" + + + + + +//////////////////////////////////////////////////////////////////////////////// +// Globals: + +static bool IsValidSocket(evutil_socket_t a_Socket) +{ + #ifdef _WIN32 + return (a_Socket != INVALID_SOCKET); + #else // _WIN32 + return (a_Socket >= 0); + #endif // else _WIN32 +} + + + + + +/** Converts a_SrcAddr in IPv4 format to a_DstAddr in IPv6 format (using IPv4-mapped IPv6). */ +static void ConvertIPv4ToMappedIPv6(sockaddr_in & a_SrcAddr, sockaddr_in6 & a_DstAddr) +{ + memset(&a_DstAddr, 0, sizeof(a_DstAddr)); + a_DstAddr.sin6_family = AF_INET6; + a_DstAddr.sin6_addr.s6_addr[10] = 0xff; + a_DstAddr.sin6_addr.s6_addr[11] = 0xff; + a_DstAddr.sin6_addr.s6_addr[12] = static_cast<Byte>((a_SrcAddr.sin_addr.s_addr >> 0) & 0xff); + a_DstAddr.sin6_addr.s6_addr[13] = static_cast<Byte>((a_SrcAddr.sin_addr.s_addr >> 8) & 0xff); + a_DstAddr.sin6_addr.s6_addr[14] = static_cast<Byte>((a_SrcAddr.sin_addr.s_addr >> 16) & 0xff); + a_DstAddr.sin6_addr.s6_addr[15] = static_cast<Byte>((a_SrcAddr.sin_addr.s_addr >> 24) & 0xff); + a_DstAddr.sin6_port = a_SrcAddr.sin_port; +} + + + + + +//////////////////////////////////////////////////////////////////////////////// +// cUDPSendAfterLookup: + +/** A hostname-to-IP resolver callback that sends the data stored within to the resolved IP address. +This is used for sending UDP datagrams to hostnames, so that the cUDPEndpoint::Send() doesn't block. +Instead an instance of this callback is queued for resolving and the data is sent once the IP is resolved. */ +class cUDPSendAfterLookup: + public cNetwork::cResolveNameCallbacks +{ +public: + cUDPSendAfterLookup(const AString & a_Data, UInt16 a_Port, evutil_socket_t a_MainSock, evutil_socket_t a_SecondSock, bool a_IsMainSockIPv6): + m_Data(a_Data), + m_Port(a_Port), + m_MainSock(a_MainSock), + m_SecondSock(a_SecondSock), + m_IsMainSockIPv6(a_IsMainSockIPv6), + m_HasIPv4(false), + m_HasIPv6(false) + { + } + +protected: + /** The data to send after the hostname is resolved. */ + AString m_Data; + + /** The port to which to send the data. */ + UInt16 m_Port; + + /** The primary socket to use for sending. */ + evutil_socket_t m_MainSock; + + /** The secondary socket to use for sending, if needed by the OS. */ + evutil_socket_t m_SecondSock; + + /** True if m_MainSock is an IPv6 socket. */ + bool m_IsMainSockIPv6; + + /** The IPv4 address resolved, if any. */ + sockaddr_in m_AddrIPv4; + + /** Set to true if the name resolved to an IPv4 address. */ + bool m_HasIPv4; + + /** The IPv6 address resolved, if any. */ + sockaddr_in6 m_AddrIPv6; + + /** Set to true if the name resolved to an IPv6 address. */ + bool m_HasIPv6; + + + // cNetwork::cResolveNameCallbacks overrides: + virtual void OnNameResolved(const AString & a_Name, const AString & a_PI) override + { + // Not needed + } + + virtual bool OnNameResolvedV4(const AString & a_Name, const sockaddr_in * a_IP) override + { + if (!m_HasIPv4) + { + m_AddrIPv4 = *a_IP; + m_AddrIPv4.sin_port = htons(m_Port); + m_HasIPv4 = true; + } + + // Don't want OnNameResolved() callback + return false; + } + + virtual bool OnNameResolvedV6(const AString & a_Name, const sockaddr_in6 * a_IP) override + { + if (!m_HasIPv6) + { + m_AddrIPv6 = *a_IP; + m_AddrIPv6.sin6_port = htons(m_Port); + m_HasIPv6 = true; + } + + // Don't want OnNameResolved() callback + return false; + } + + virtual void OnFinished(void) override + { + // Send the actual data, through the correct socket and using the correct resolved address: + if (m_IsMainSockIPv6) + { + if (m_HasIPv6) + { + sendto(m_MainSock, m_Data.data(), static_cast<socklen_t>(m_Data.size()), 0, reinterpret_cast<const sockaddr *>(&m_AddrIPv6), static_cast<socklen_t>(sizeof(m_AddrIPv6))); + } + else if (m_HasIPv4) + { + // If the secondary socket is valid, it is an IPv4 socket, so use that: + if (m_SecondSock != -1) + { + sendto(m_SecondSock, m_Data.data(), static_cast<socklen_t>(m_Data.size()), 0, reinterpret_cast<const sockaddr *>(&m_AddrIPv4), static_cast<socklen_t>(sizeof(m_AddrIPv4))); + } + else + { + // Need an address conversion from IPv4 to IPv6-mapped-IPv4: + ConvertIPv4ToMappedIPv6(m_AddrIPv4, m_AddrIPv6); + sendto(m_MainSock, m_Data.data(), static_cast<socklen_t>(m_Data.size()), 0, reinterpret_cast<const sockaddr *>(&m_AddrIPv6), static_cast<socklen_t>(sizeof(m_AddrIPv6))); + } + } + else + { + LOGD("UDP endpoint queued sendto: Name not resolved"); + return; + } + } + else // m_IsMainSockIPv6 + { + // Main socket is IPv4 only, only allow IPv4 dst address: + if (!m_HasIPv4) + { + LOGD("UDP endpoint queued sendto: Name not resolved to IPv4 for an IPv4-only socket"); + return; + } + sendto(m_MainSock, m_Data.data(), static_cast<socklen_t>(m_Data.size()), 0, reinterpret_cast<const sockaddr *>(&m_AddrIPv4), static_cast<socklen_t>(sizeof(m_AddrIPv4))); + } + } + + virtual void OnError(int a_ErrorCode, const AString & a_ErrorMsg) override + { + // Nothing needed + } +}; + + + + + +//////////////////////////////////////////////////////////////////////////////// +// cUDPEndpointImpl: + +cUDPEndpointImpl::cUDPEndpointImpl(UInt16 a_Port, cUDPEndpoint::cCallbacks & a_Callbacks): + super(a_Callbacks), + m_Port(0), + m_MainSock(-1), + m_IsMainSockIPv6(true), + m_SecondarySock(-1), + m_MainEvent(nullptr), + m_SecondaryEvent(nullptr) +{ + Open(a_Port); +} + + + + + +void cUDPEndpointImpl::Close(void) +{ + if (m_Port == 0) + { + // Already closed + return; + } + + // Close the LibEvent handles: + if (m_MainEvent != nullptr) + { + event_free(m_MainEvent); + m_MainEvent = nullptr; + } + if (m_SecondaryEvent != nullptr) + { + event_free(m_SecondaryEvent); + m_SecondaryEvent = nullptr; + } + + // Close the OS sockets: + evutil_closesocket(m_MainSock); + m_MainSock = -1; + evutil_closesocket(m_SecondarySock); + m_SecondarySock = -1; + + // Mark as closed: + m_Port = 0; +} + + + + + +bool cUDPEndpointImpl::IsOpen(void) const +{ + return (m_Port != 0); +} + + + + + +UInt16 cUDPEndpointImpl::GetPort(void) const +{ + return m_Port; +} + + + + + +bool cUDPEndpointImpl::Send(const AString & a_Payload, const AString & a_Host, UInt16 a_Port) +{ + // If a_Host is an IP address, send the data directly: + sockaddr_storage sa; + int salen = static_cast<int>(sizeof(sa)); + memset(&sa, 0, sizeof(sa)); + if (evutil_parse_sockaddr_port(a_Host.c_str(), reinterpret_cast<sockaddr *>(&sa), &salen) != 0) + { + // a_Host is a hostname, we need to do a lookup first: + auto queue = std::make_shared<cUDPSendAfterLookup>(a_Payload, a_Port, m_MainSock, m_SecondarySock, m_IsMainSockIPv6); + return cNetwork::HostnameToIP(a_Host, queue); + } + + // a_Host is an IP address and has been parsed into "sa" + // Insert the correct port and send data: + int NumSent; + switch (sa.ss_family) + { + case AF_INET: + { + reinterpret_cast<sockaddr_in *>(&sa)->sin_port = htons(a_Port); + if (m_IsMainSockIPv6) + { + if (IsValidSocket(m_SecondarySock)) + { + // The secondary socket, which is always IPv4, is present: + NumSent = static_cast<int>(sendto(m_SecondarySock, a_Payload.data(), static_cast<socklen_t>(a_Payload.size()), 0, reinterpret_cast<const sockaddr *>(&sa), static_cast<socklen_t>(salen))); + } + else + { + // Need to convert IPv4 to IPv6 address before sending: + sockaddr_in6 IPv6; + ConvertIPv4ToMappedIPv6(*reinterpret_cast<sockaddr_in *>(&sa), IPv6); + NumSent = static_cast<int>(sendto(m_MainSock, a_Payload.data(), static_cast<socklen_t>(a_Payload.size()), 0, reinterpret_cast<const sockaddr *>(&IPv6), static_cast<socklen_t>(sizeof(IPv6)))); + } + } + else + { + NumSent = static_cast<int>(sendto(m_MainSock, a_Payload.data(), static_cast<socklen_t>(a_Payload.size()), 0, reinterpret_cast<const sockaddr *>(&sa), static_cast<socklen_t>(salen))); + } + break; + } + + case AF_INET6: + { + reinterpret_cast<sockaddr_in6 *>(&sa)->sin6_port = htons(a_Port); + NumSent = static_cast<int>(sendto(m_MainSock, a_Payload.data(), static_cast<socklen_t>(a_Payload.size()), 0, reinterpret_cast<const sockaddr *>(&sa), static_cast<socklen_t>(salen))); + break; + } + default: + { + LOGD("UDP sendto: Invalid address family for address \"%s\".", a_Host.c_str()); + return false; + } + } + return (NumSent > 0); +} + + + + + +void cUDPEndpointImpl::EnableBroadcasts(void) +{ + ASSERT(IsOpen()); + + // Enable broadcasts on the main socket: + // Some OSes use ints, others use chars, so we try both + int broadcastInt = 1; + char broadcastChar = 1; + // (Note that Windows uses const char * for option values, while Linux uses const void *) + if (setsockopt(m_MainSock, SOL_SOCKET, SO_BROADCAST, reinterpret_cast<const char *>(&broadcastInt), sizeof(broadcastInt)) == -1) + { + if (setsockopt(m_MainSock, SOL_SOCKET, SO_BROADCAST, &broadcastChar, sizeof(broadcastChar)) == -1) + { + int err = EVUTIL_SOCKET_ERROR(); + LOGWARNING("Cannot enable broadcasts on port %d: %d (%s)", m_Port, err, evutil_socket_error_to_string(err)); + return; + } + + // Enable broadcasts on the secondary socket, if opened (use char, it worked for primary): + if (IsValidSocket(m_SecondarySock)) + { + if (setsockopt(m_SecondarySock, SOL_SOCKET, SO_BROADCAST, &broadcastChar, sizeof(broadcastChar)) == -1) + { + int err = EVUTIL_SOCKET_ERROR(); + LOGWARNING("Cannot enable broadcasts on port %d (secondary): %d (%s)", m_Port, err, evutil_socket_error_to_string(err)); + } + } + return; + } + + // Enable broadcasts on the secondary socket, if opened (use int, it worked for primary): + if (IsValidSocket(m_SecondarySock)) + { + if (setsockopt(m_SecondarySock, SOL_SOCKET, SO_BROADCAST, reinterpret_cast<const char *>(&broadcastInt), sizeof(broadcastInt)) == -1) + { + int err = EVUTIL_SOCKET_ERROR(); + LOGWARNING("Cannot enable broadcasts on port %d (secondary): %d (%s)", m_Port, err, evutil_socket_error_to_string(err)); + } + } +} + + + + + +void cUDPEndpointImpl::Open(UInt16 a_Port) +{ + ASSERT(m_Port == 0); // Must not be already open + + // Make sure the cNetwork internals are innitialized: + cNetworkSingleton::Get(); + + // Set up the main socket: + // It should listen on IPv6 with IPv4 fallback, when available; IPv4 when IPv6 is not available. + bool NeedsTwoSockets = false; + m_IsMainSockIPv6 = true; + m_MainSock = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP); + + int err; + if (!IsValidSocket(m_MainSock)) + { + // Failed to create IPv6 socket, create an IPv4 one instead: + m_IsMainSockIPv6 = false; + err = EVUTIL_SOCKET_ERROR(); + LOGD("Failed to create IPv6 MainSock: %d (%s)", err, evutil_socket_error_to_string(err)); + m_MainSock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); + if (!IsValidSocket(m_MainSock)) + { + err = EVUTIL_SOCKET_ERROR(); + m_Callbacks.OnError(err, Printf("Cannot create UDP socket for port %d: %s", a_Port, evutil_socket_error_to_string(err))); + return; + } + + // Allow the port to be reused right after the socket closes: + if (evutil_make_listen_socket_reuseable(m_MainSock) != 0) + { + err = EVUTIL_SOCKET_ERROR(); + LOG("UDP Port %d cannot be made reusable: %d (%s). Restarting the server might not work.", + a_Port, err, evutil_socket_error_to_string(err) + ); + } + + // Bind to all interfaces: + sockaddr_in name; + memset(&name, 0, sizeof(name)); + name.sin_family = AF_INET; + name.sin_port = ntohs(a_Port); + if (bind(m_MainSock, reinterpret_cast<const sockaddr *>(&name), sizeof(name)) != 0) + { + err = EVUTIL_SOCKET_ERROR(); + m_Callbacks.OnError(err, Printf("Cannot bind UDP port %d: %s", a_Port, evutil_socket_error_to_string(err))); + evutil_closesocket(m_MainSock); + return; + } + } + else + { + // IPv6 socket created, switch it into "dualstack" mode: + UInt32 Zero = 0; + #ifdef _WIN32 + // WinXP doesn't support this feature, so if the setting fails, create another socket later on: + int res = setsockopt(m_MainSock, IPPROTO_IPV6, IPV6_V6ONLY, reinterpret_cast<const char *>(&Zero), sizeof(Zero)); + err = EVUTIL_SOCKET_ERROR(); + NeedsTwoSockets = ((res == SOCKET_ERROR) && (err == WSAENOPROTOOPT)); + #else + setsockopt(m_MainSock, IPPROTO_IPV6, IPV6_V6ONLY, reinterpret_cast<const char *>(&Zero), sizeof(Zero)); + #endif + + // Allow the port to be reused right after the socket closes: + if (evutil_make_listen_socket_reuseable(m_MainSock) != 0) + { + err = EVUTIL_SOCKET_ERROR(); + LOG("UDP Port %d cannot be made reusable: %d (%s). Restarting the server might not work.", + a_Port, err, evutil_socket_error_to_string(err) + ); + } + + // Bind to all interfaces: + sockaddr_in6 name; + memset(&name, 0, sizeof(name)); + name.sin6_family = AF_INET6; + name.sin6_port = ntohs(a_Port); + if (bind(m_MainSock, reinterpret_cast<const sockaddr *>(&name), sizeof(name)) != 0) + { + err = EVUTIL_SOCKET_ERROR(); + m_Callbacks.OnError(err, Printf("Cannot bind to UDP port %d: %s", a_Port, evutil_socket_error_to_string(err))); + evutil_closesocket(m_MainSock); + return; + } + } + if (evutil_make_socket_nonblocking(m_MainSock) != 0) + { + err = EVUTIL_SOCKET_ERROR(); + m_Callbacks.OnError(err, Printf("Cannot make socket on UDP port %d nonblocking: %s", a_Port, evutil_socket_error_to_string(err))); + evutil_closesocket(m_MainSock); + return; + } + m_MainEvent = event_new(cNetworkSingleton::Get().GetEventBase(), m_MainSock, EV_READ | EV_PERSIST, RawCallback, this); + event_add(m_MainEvent, nullptr); + + // Read the actual port number on which the socket is listening: + { + sockaddr_storage name; + socklen_t namelen = static_cast<socklen_t>(sizeof(name)); + getsockname(m_MainSock, reinterpret_cast<sockaddr *>(&name), &namelen); + switch (name.ss_family) + { + case AF_INET: + { + sockaddr_in * sin = reinterpret_cast<sockaddr_in *>(&name); + m_Port = ntohs(sin->sin_port); + break; + } + case AF_INET6: + { + sockaddr_in6 * sin6 = reinterpret_cast<sockaddr_in6 *>(&name); + m_Port = ntohs(sin6->sin6_port); + break; + } + } + } + + // If we don't need to create another socket, bail out now: + if (!NeedsTwoSockets) + { + return; + } + + // If a secondary socket is required (WinXP dual-stack), create it here: + LOGD("Creating a second UDP socket for IPv4"); + m_SecondarySock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); + + if (!IsValidSocket(m_SecondarySock)) + { + // Don't report as an error, the primary socket is working + err = EVUTIL_SOCKET_ERROR(); + LOGD("Socket creation failed for secondary UDP socket for port %d: %d, %s", m_Port, err, evutil_socket_error_to_string(err)); + return; + } + + // Allow the port to be reused right after the socket closes: + if (evutil_make_listen_socket_reuseable(m_SecondarySock) != 0) + { + // Don't report as an error, the primary socket is working + err = EVUTIL_SOCKET_ERROR(); + LOGD("UDP Port %d cannot be made reusable (second socket): %d (%s). Restarting the server might not work.", + a_Port, err, evutil_socket_error_to_string(err) + ); + evutil_closesocket(m_SecondarySock); + m_SecondarySock = -1; + return; + } + + // Make the secondary socket nonblocking: + if (evutil_make_socket_nonblocking(m_SecondarySock) != 0) + { + // Don't report as an error, the primary socket is working + err = EVUTIL_SOCKET_ERROR(); + LOGD("evutil_make_socket_nonblocking() failed for secondary UDP socket: %d, %s", err, evutil_socket_error_to_string(err)); + evutil_closesocket(m_SecondarySock); + m_SecondarySock = -1; + return; + } + + // Bind to all IPv4 interfaces: + sockaddr_in name; + memset(&name, 0, sizeof(name)); + name.sin_family = AF_INET; + name.sin_port = ntohs(m_Port); + if (bind(m_SecondarySock, reinterpret_cast<const sockaddr *>(&name), sizeof(name)) != 0) + { + // Don't report as an error, the primary socket is working + err = EVUTIL_SOCKET_ERROR(); + LOGD("Cannot bind secondary socket to UDP port %d: %d (%s)", m_Port, err, evutil_socket_error_to_string(err)); + evutil_closesocket(m_SecondarySock); + m_SecondarySock = -1; + return; + } + + m_SecondaryEvent = event_new(cNetworkSingleton::Get().GetEventBase(), m_SecondarySock, EV_READ | EV_PERSIST, RawCallback, this); + event_add(m_SecondaryEvent, nullptr); +} + + + + + +void cUDPEndpointImpl::RawCallback(evutil_socket_t a_Socket, short a_What, void * a_Self) +{ + cUDPEndpointImpl * Self = reinterpret_cast<cUDPEndpointImpl *>(a_Self); + Self->Callback(a_Socket, a_What); +} + + + + + +void cUDPEndpointImpl::Callback(evutil_socket_t a_Socket, short a_What) +{ + if ((a_What & EV_READ) != 0) + { + // Receive datagram from the socket: + char buf[64 KiB]; + socklen_t buflen = static_cast<socklen_t>(sizeof(buf)); + sockaddr_storage sa; + socklen_t salen = static_cast<socklen_t>(sizeof(sa)); + auto len = recvfrom(a_Socket, buf, buflen, 0, reinterpret_cast<sockaddr *>(&sa), &salen); + if (len >= 0) + { + // Convert the remote IP address to a string: + char RemoteHost[128]; + UInt16 RemotePort; + switch (sa.ss_family) + { + case AF_INET: + { + auto sin = reinterpret_cast<sockaddr_in *>(&sa); + evutil_inet_ntop(sa.ss_family, &sin->sin_addr, RemoteHost, sizeof(RemoteHost)); + RemotePort = ntohs(sin->sin_port); + break; + } + case AF_INET6: + { + auto sin = reinterpret_cast<sockaddr_in6 *>(&sa); + evutil_inet_ntop(sa.ss_family, &sin->sin6_addr, RemoteHost, sizeof(RemoteHost)); + RemotePort = ntohs(sin->sin6_port); + break; + } + default: + { + return; + } + } + + // Call the callback: + m_Callbacks.OnReceivedData(buf, static_cast<size_t>(len), RemoteHost, RemotePort); + } + } +} + + + + + +//////////////////////////////////////////////////////////////////////////////// +// cNetwork API: + +cUDPEndpointPtr cNetwork::CreateUDPEndpoint(UInt16 a_Port, cUDPEndpoint::cCallbacks & a_Callbacks) +{ + return std::make_shared<cUDPEndpointImpl>(a_Port, a_Callbacks); +} + + + + |