Adds a UDPClient (#60)

Send only currently. Will eventually implement receive, but not
necessary for now.

build.gradle

@@ -56,11 +56,11 @@ model {
             x86ExcludeSymbols = [ '_CT??_R0?AV_System_error', '_CT??_R0?AVexception', '_CT??_R0?AVfailure',
                                   '_CT??_R0?AVruntime_error', '_CT??_R0?AVsystem_error', '_CTA5?AVfailure',
                                   '_TI5?AVfailure', '_CT??_R0?AVout_of_range', '_CTA3?AVout_of_range',
-                                  '_TI3?AVout_of_range' ]
+                                  '_TI3?AVout_of_range', '_CT??_R0?AVbad_cast' ]
             x64ExcludeSymbols = [ '_CT??_R0?AV_System_error', '_CT??_R0?AVexception', '_CT??_R0?AVfailure',
                                   '_CT??_R0?AVruntime_error', '_CT??_R0?AVsystem_error', '_CTA5?AVfailure',
                                   '_TI5?AVfailure', '_CT??_R0?AVout_of_range', '_CTA3?AVout_of_range',
-                                  '_TI3?AVout_of_range' ]
+                                  '_TI3?AVout_of_range', '_CT??_R0?AVbad_cast' ]
         }
     }
     jniConfigs {

src/main/native/cpp/udpsockets/UDPClient.cpp

@@ -0,0 +1,175 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2017. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "udpsockets/UDPClient.h"
+
+#ifdef _WIN32
+#include <WinSock2.h>
+#include <Ws2tcpip.h>
+#pragma comment(lib, "Ws2_32.lib")
+#else
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <unistd.h>
+#include <fcntl.h>
+#endif
+
+#include "support/Logger.h"
+#include "tcpsockets/SocketError.h"
+
+
+using namespace wpi;
+
+UDPClient::UDPClient(Logger& logger)
+    : UDPClient("", logger) {}
+
+UDPClient::UDPClient(llvm::StringRef address, Logger& logger)
+    : m_lsd(0),
+      m_address(address),
+      m_logger(logger) {}
+
+UDPClient::UDPClient(UDPClient&& other)
+    : m_lsd(other.m_lsd),
+      m_address(std::move(other.m_address)),
+      m_logger(other.m_logger) {
+  other.m_lsd = 0;
+}
+
+UDPClient::~UDPClient() {
+  if (m_lsd > 0) {
+    shutdown();
+  }
+}
+
+UDPClient& UDPClient::operator=(UDPClient&& other) {
+  if (this == &other) return *this;
+  shutdown();
+  m_logger = other.m_logger;
+  m_lsd = other.m_lsd;
+  m_address = std::move(other.m_address);
+  other.m_lsd = 0;
+  return *this;
+}
+
+int UDPClient::start() {
+  if (m_lsd > 0) return 0;
+
+#ifdef _WIN32
+  WSAData wsaData;
+  WORD wVersionRequested = MAKEWORD(2, 2);
+  WSAStartup(wVersionRequested, &wsaData);
+#endif
+
+  m_lsd = socket(AF_INET, SOCK_DGRAM, 0);
+
+  if (m_lsd < 0) {
+    WPI_ERROR(m_logger, "could not create socket");
+    return -1;
+  }
+
+  struct sockaddr_in addr;
+  std::memset(&addr, 0, sizeof(addr));
+  addr.sin_family = AF_INET;
+  if (m_address.size() > 0) {
+#ifdef _WIN32
+    llvm::SmallString<128> addr_copy(m_address);
+    addr_copy.push_back('\0');
+    int res = InetPton(PF_INET, addr_copy.data(), &(addr.sin_addr));
+#else
+    int res = inet_pton(PF_INET, m_address.c_str(), &(addr.sin_addr));
+#endif
+    if (res != 1) {
+      WPI_ERROR(m_logger, "could not resolve " << m_address << " address");
+      return -1;
+    }
+  } else {
+    addr.sin_addr.s_addr = INADDR_ANY;
+  }
+  addr.sin_port = htons(0);
+
+  int result = bind(m_lsd, reinterpret_cast<sockaddr*>(&addr), sizeof(addr));
+  if (result != 0) {
+    WPI_ERROR(m_logger, "bind() failed: " << SocketStrerror());
+    return result;
+  }
+  return 0;
+}
+
+void UDPClient::shutdown() {
+  if (m_lsd > 0) {
+#ifdef _WIN32
+    ::shutdown(m_lsd, SD_BOTH);
+    closesocket(m_lsd);
+    WSACleanup();
+#else
+    ::shutdown(m_lsd, SHUT_RDWR);
+    close(m_lsd);
+#endif
+    m_lsd = 0;
+  }
+}
+
+int UDPClient::send(llvm::ArrayRef<uint8_t> data,
+                    llvm::StringRef server, int port) {
+  // server must be a resolvable IP address
+  struct sockaddr_in addr;
+  std::memset(&addr, 0, sizeof(addr));
+  addr.sin_family = AF_INET;
+  if (server.size() > 0) {
+    llvm::SmallVector<char, 128> addr_store;
+    auto remoteAddr = server.c_str(addr_store);
+#ifdef _WIN32
+    int res = InetPton(AF_INET, remoteAddr, &(addr.sin_addr));
+#else
+    int res = inet_pton(AF_INET, remoteAddr, &(addr.sin_addr));
+#endif
+    if (res != 1) {
+      WPI_ERROR(m_logger, "could not resolve " << server << " address");
+      return -1;
+    }
+  } else {
+    WPI_ERROR(m_logger, "server must be passed");
+    return -1;
+  }
+  addr.sin_port = htons(port);
+
+  // sendto should not block
+  int result = sendto(m_lsd, reinterpret_cast<const char*>(data.data()),
+                      data.size(), 0, reinterpret_cast<sockaddr*>(&addr),
+                      sizeof(addr));
+  return result;
+}
+
+int UDPClient::send(llvm::StringRef data,
+                    llvm::StringRef server, int port) {
+  // server must be a resolvable IP address
+  struct sockaddr_in addr;
+  std::memset(&addr, 0, sizeof(addr));
+  addr.sin_family = AF_INET;
+  if (server.size() > 0) {
+    llvm::SmallVector<char, 128> addr_store;
+    auto remoteAddr = server.c_str(addr_store);
+#ifdef _WIN32
+    int res = InetPton(AF_INET, remoteAddr, &(addr.sin_addr));
+#else
+    int res = inet_pton(AF_INET, remoteAddr, &(addr.sin_addr));
+#endif
+    if (res != 1) {
+      WPI_ERROR(m_logger, "could not resolve " << server << " address");
+      return -1;
+    }
+  } else {
+    WPI_ERROR(m_logger, "server must be passed");
+    return -1;
+  }
+  addr.sin_port = htons(port);
+
+  // sendto should not block
+  int result = sendto(m_lsd, data.data(), data.size(), 0,
+                      reinterpret_cast<sockaddr*>(&addr), sizeof(addr));
+  return result;
+}

src/main/native/include/udpsockets/UDPClient.h

@@ -0,0 +1,46 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2017. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_UDPSOCKETS_UDPCLIENT_H_
+#define WPIUTIL_UDPSOCKETS_UDPCLIENT_H_
+
+#include <string>
+
+#include "llvm/ArrayRef.h"
+#include "llvm/StringRef.h"
+#include "support/mutex.h"
+
+
+namespace wpi {
+
+class Logger;
+
+class UDPClient {
+  int m_lsd;
+  std::string m_address;
+  Logger& m_logger;
+
+public:
+  explicit UDPClient(Logger& logger);
+  UDPClient(llvm::StringRef address, Logger& logger);
+  UDPClient(const UDPClient& other) = delete;
+  UDPClient(UDPClient&& other);
+  ~UDPClient();
+
+  UDPClient& operator=(const UDPClient& other) = delete;
+  UDPClient& operator=(UDPClient&& other);
+
+  int start();
+  void shutdown();
+  // The passed in address MUST be a resolved IP address.
+  int send(llvm::ArrayRef<uint8_t> data, llvm::StringRef server, int port);
+  int send(llvm::StringRef data, llvm::StringRef server, int port);
+};
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_UDPSOCKETS_UDPCLIENT_H_