mirror of
https://github.com/oxen-io/lokinet.git
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307 lines
8.5 KiB
C++
307 lines
8.5 KiB
C++
/*
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* Copyright (c) 2010-2013 BitTorrent, Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <stdlib.h>
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#include <assert.h>
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#include "utp.h"
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#include "utp_types.h"
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#ifdef WIN32
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#ifndef WIN32_LEAN_AND_MEAN
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#define WIN32_LEAN_AND_MEAN
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#endif
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#include <windows.h>
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#include <winsock2.h>
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#include <ws2tcpip.h>
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#else //! WIN32
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#include <time.h>
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#include <sys/time.h> // Linux needs both time.h and sys/time.h
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#endif
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#if defined(__APPLE__)
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#include <mach/mach_time.h>
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#endif
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#include "utp_utils.h"
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#ifdef WIN32
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typedef ULONGLONG(WINAPI GetTickCount64Proc)(void);
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static GetTickCount64Proc *pt2GetTickCount64;
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static GetTickCount64Proc *pt2RealGetTickCount;
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static uint64 startPerformanceCounter;
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static uint64 startGetTickCount;
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// MSVC 6 standard doesn't like division with uint64s
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static double counterPerMicrosecond;
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static uint64
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UTGetTickCount64()
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{
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if(pt2GetTickCount64)
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{
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return pt2GetTickCount64();
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}
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if(pt2RealGetTickCount)
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{
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uint64 v = pt2RealGetTickCount();
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// fix return value from GetTickCount
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return (DWORD)v | ((v >> 0x18) & 0xFFFFFFFF00000000);
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}
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return (uint64)GetTickCount();
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}
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static void
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Time_Initialize()
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{
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HMODULE kernel32 = GetModuleHandleA("kernel32.dll");
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pt2GetTickCount64 =
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(GetTickCount64Proc *)GetProcAddress(kernel32, "GetTickCount64");
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// not a typo. GetTickCount actually returns 64 bits
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pt2RealGetTickCount =
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(GetTickCount64Proc *)GetProcAddress(kernel32, "GetTickCount");
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uint64 frequency;
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QueryPerformanceCounter((LARGE_INTEGER *)&startPerformanceCounter);
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QueryPerformanceFrequency((LARGE_INTEGER *)&frequency);
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counterPerMicrosecond = (double)frequency / 1000000.0f;
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startGetTickCount = UTGetTickCount64();
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}
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static int64
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abs64(int64 x)
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{
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return x < 0 ? -x : x;
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}
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static uint64
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__GetMicroseconds()
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{
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static bool time_init = false;
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if(!time_init)
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{
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time_init = true;
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Time_Initialize();
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}
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uint64 counter;
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uint64 tick;
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QueryPerformanceCounter((LARGE_INTEGER *)&counter);
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tick = UTGetTickCount64();
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// unfortunately, QueryPerformanceCounter is not guaranteed
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// to be monotonic. Make it so.
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int64 ret = (int64)(((int64)counter - (int64)startPerformanceCounter)
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/ counterPerMicrosecond);
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// if the QPC clock leaps more than one second off GetTickCount64()
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// something is seriously fishy. Adjust QPC to stay monotonic
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int64 tick_diff = tick - startGetTickCount;
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if(abs64(ret / 100000 - tick_diff / 100) > 10)
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{
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startPerformanceCounter -=
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(uint64)((int64)(tick_diff * 1000 - ret) * counterPerMicrosecond);
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ret = (int64)((counter - startPerformanceCounter) / counterPerMicrosecond);
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}
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return ret;
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}
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static inline uint64
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UTP_GetMilliseconds()
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{
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return GetTickCount();
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}
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#else //! WIN32
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static inline uint64
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UTP_GetMicroseconds(void);
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static inline uint64
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UTP_GetMilliseconds()
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{
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return UTP_GetMicroseconds() / 1000;
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}
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#if defined(__APPLE__)
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static uint64
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__GetMicroseconds()
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{
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// http://developer.apple.com/mac/library/qa/qa2004/qa1398.html
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// http://www.macresearch.org/tutorial_performance_and_time
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static mach_timebase_info_data_t sTimebaseInfo;
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static uint64_t start_tick = 0;
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uint64_t tick;
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// Returns a counter in some fraction of a nanoseconds
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tick = mach_absolute_time();
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if(sTimebaseInfo.denom == 0)
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{
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// Get the timer ratio to convert mach_absolute_time to nanoseconds
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mach_timebase_info(&sTimebaseInfo);
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start_tick = tick;
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}
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// Calculate the elapsed time, convert it to microseconds and return it.
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return ((tick - start_tick) * sTimebaseInfo.numer)
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/ (sTimebaseInfo.denom * 1000);
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}
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#else // !__APPLE__
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// While _POSIX_TIMERS == -1 in openbsd, clock_gettime(2) _does_ support monotonic.
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// this is true for all the BSDs
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#if !(__OpenBSD__ || __NetBSD__ || __FreeBSD__)
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#if !(defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0 && defined(CLOCK_MONOTONIC))
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#warning "Using non-monotonic function gettimeofday() in UTP_GetMicroseconds()"
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#endif
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#endif
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/* Unfortunately, #ifdef CLOCK_MONOTONIC is not enough to make sure that
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POSIX clocks work -- we could be running a recent libc with an ancient
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kernel (think OpenWRT). -- jch */
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static uint64_t
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__GetMicroseconds()
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{
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struct timeval tv;
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#if defined(CLOCK_MONOTONIC)
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static int have_posix_clocks = -1;
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int rc;
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if(have_posix_clocks < 0)
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{
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struct timespec ts;
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rc = clock_gettime(CLOCK_MONOTONIC, &ts);
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if(rc < 0)
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{
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have_posix_clocks = 0;
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}
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else
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{
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have_posix_clocks = 1;
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}
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}
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if(have_posix_clocks)
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{
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struct timespec ts;
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rc = clock_gettime(CLOCK_MONOTONIC, &ts);
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return uint64(ts.tv_sec) * 1000000 + uint64(ts.tv_nsec) / 1000;
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}
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#endif
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gettimeofday(&tv, NULL);
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return uint64(tv.tv_sec) * 1000000 + tv.tv_usec;
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}
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#endif //!__APPLE__
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#endif //! WIN32
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/*
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* Whew. Okay. After that #ifdef maze above, we now know we have a working
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* __GetMicroseconds() implementation on all platforms.
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*
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* Because there are a number of assertions in libutp that will cause a crash
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* if monotonic time isn't monotonic, now apply some safety checks. While in
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* principle we're already protecting ourselves in cases where non-monotonic
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* time is likely to happen, this protects all versions.
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*/
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static inline uint64
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UTP_GetMicroseconds()
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{
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static uint64 offset = 0, previous = 0;
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uint64 now = __GetMicroseconds() + offset;
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if(previous > now)
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{
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/* Eek! */
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offset += previous - now;
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now = previous;
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}
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previous = now;
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return now;
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}
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#define ETHERNET_MTU 1500
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#define IPV4_HEADER_SIZE 20
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#define IPV6_HEADER_SIZE 40
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#define UDP_HEADER_SIZE 8
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#define GRE_HEADER_SIZE 24
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#define PPPOE_HEADER_SIZE 8
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#define MPPE_HEADER_SIZE 2
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// packets have been observed in the wild that were fragmented
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// with a payload of 1416 for the first fragment
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// There are reports of routers that have MTU sizes as small as 1392
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#define FUDGE_HEADER_SIZE 36
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#define TEREDO_MTU 1280
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#define UDP_IPV4_OVERHEAD (IPV4_HEADER_SIZE + UDP_HEADER_SIZE)
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#define UDP_IPV6_OVERHEAD (IPV6_HEADER_SIZE + UDP_HEADER_SIZE)
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#define UDP_TEREDO_OVERHEAD (UDP_IPV4_OVERHEAD + UDP_IPV6_OVERHEAD)
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#define UDP_IPV4_MTU \
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(ETHERNET_MTU - IPV4_HEADER_SIZE - UDP_HEADER_SIZE - GRE_HEADER_SIZE \
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- PPPOE_HEADER_SIZE - MPPE_HEADER_SIZE - FUDGE_HEADER_SIZE)
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#define UDP_IPV6_MTU \
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(ETHERNET_MTU - IPV6_HEADER_SIZE - UDP_HEADER_SIZE - GRE_HEADER_SIZE \
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- PPPOE_HEADER_SIZE - MPPE_HEADER_SIZE - FUDGE_HEADER_SIZE)
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#define UDP_TEREDO_MTU (TEREDO_MTU - IPV6_HEADER_SIZE - UDP_HEADER_SIZE)
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uint64
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utp_default_get_udp_mtu(utp_callback_arguments *args)
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{
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// Since we don't know the local address of the interface,
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// be conservative and assume all IPv6 connections are Teredo.
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return (args->address->sa_family == AF_INET6) ? UDP_TEREDO_MTU : UDP_IPV4_MTU;
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}
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uint64
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utp_default_get_udp_overhead(utp_callback_arguments *args)
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{
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// Since we don't know the local address of the interface,
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// be conservative and assume all IPv6 connections are Teredo.
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return (args->address->sa_family == AF_INET6) ? UDP_TEREDO_OVERHEAD
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: UDP_IPV4_OVERHEAD;
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}
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uint64
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utp_default_get_random(__attribute__((unused)) utp_callback_arguments *args)
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{
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return rand();
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}
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uint64
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utp_default_get_milliseconds(__attribute__((unused))
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utp_callback_arguments *args)
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{
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return UTP_GetMilliseconds();
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}
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uint64
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utp_default_get_microseconds(__attribute__((unused))
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utp_callback_arguments *args)
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{
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return UTP_GetMicroseconds();
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}
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