From 3afe6c23a07b7663ebca7860e4a9b434ba25a673 Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@libtorrent.org>
Date: Sat, 31 Aug 2013 21:06:43 +0000
Subject: [PATCH] merged tracker key patch from RC_0_16

---
 include/libtorrent/hasher.hpp          |  4 ++--
 include/libtorrent/torrent.hpp         |  4 ++++
 include/libtorrent/tracker_manager.hpp |  2 +-
 src/hasher.cpp                         |  3 ++-
 src/session_impl.cpp                   |  2 +-
 src/torrent.cpp                        | 17 ++++++++++++++++-
 6 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/include/libtorrent/hasher.hpp b/include/libtorrent/hasher.hpp
index c234a7160..2c4bd1495 100644
--- a/include/libtorrent/hasher.hpp
+++ b/include/libtorrent/hasher.hpp
@@ -101,8 +101,8 @@ namespace libtorrent
 		hasher& operator=(hasher const& h);
 #endif
 
-		void update(std::string const& data) { update(data.c_str(), data.size()); }
-		void update(const char* data, int len);
+		hasher& update(std::string const& data) { update(data.c_str(), data.size()); return *this; }
+		hasher& update(const char* data, int len);
 		sha1_hash final();
 
 		void reset();
diff --git a/include/libtorrent/torrent.hpp b/include/libtorrent/torrent.hpp
index e67808cd5..888d3c1e8 100644
--- a/include/libtorrent/torrent.hpp
+++ b/include/libtorrent/torrent.hpp
@@ -467,6 +467,10 @@ namespace libtorrent
 		// base64 encoding).
 		std::string tracker_login() const;
 
+		// generate the tracker key for this torrent.
+		// The key is passed to http trackers as ``&key=``.
+		boost::uint32_t tracker_key() const;
+
 		// if we need a connect boost, connect some peers
 		// immediately
 		void do_connect_boost();
diff --git a/include/libtorrent/tracker_manager.hpp b/include/libtorrent/tracker_manager.hpp
index 0027e3f07..885490a00 100644
--- a/include/libtorrent/tracker_manager.hpp
+++ b/include/libtorrent/tracker_manager.hpp
@@ -125,7 +125,7 @@ namespace libtorrent
 		event_t event;
 		std::string url;
 		std::string trackerid;
-		int key;
+		boost::uint32_t key;
 		int num_want;
 		address bind_ip;
 		bool send_stats;
diff --git a/src/hasher.cpp b/src/hasher.cpp
index 4d1322770..a6a4a1ed3 100644
--- a/src/hasher.cpp
+++ b/src/hasher.cpp
@@ -80,7 +80,7 @@ namespace libtorrent
 	}
 #endif
 
-	void hasher::update(const char* data, int len)
+	hasher& hasher::update(const char* data, int len)
 	{
 		TORRENT_ASSERT(data != 0);
 		TORRENT_ASSERT(len > 0);
@@ -93,6 +93,7 @@ namespace libtorrent
 #else
 		SHA1_update(&m_context, reinterpret_cast<unsigned char const*>(data), len);
 #endif
+		return *this;
 	}
 
 	sha1_hash hasher::final()
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index ad3729d7e..739147b10 100644
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -628,6 +628,7 @@ namespace aux {
 		, m_tracker_manager(*this, m_proxy)
 		, m_num_active_downloading(0)
 		, m_num_active_finished(0)
+		, m_key(0)
 		, m_listen_port_retries(listen_port_range.second - listen_port_range.first)
 #if TORRENT_USE_I2P
 		, m_i2p_conn(m_io_service)
@@ -725,7 +726,6 @@ namespace aux {
 		// ---- generate a peer id ----
 		static seed_random_generator seeder;
 
-		m_key = random() + (random() << 15) + (random() << 30);
 		std::string print = cl_fprint.to_string();
 		TORRENT_ASSERT_VAL(print.length() <= 20, print.length());
 
diff --git a/src/torrent.cpp b/src/torrent.cpp
index 0e3f3e07c..d76b7b47d 100644
--- a/src/torrent.cpp
+++ b/src/torrent.cpp
@@ -2358,7 +2358,10 @@ namespace libtorrent
 		else
 #endif
 		req.listen_port = m_ses.listen_port();
-		req.key = m_ses.m_key;
+		if (m_ses.m_key)
+			req.key = m_ses.m_key;
+		else
+			req.key = tracker_key();
 
 		ptime now = time_now_hires();
 
@@ -3780,6 +3783,18 @@ namespace libtorrent
 		return m_username + ":" + m_password;
 	}
 
+	boost::uint32_t torrent::tracker_key() const
+	{
+		uintptr_t self = (uintptr_t)this;
+		uintptr_t ses = (uintptr_t)&m_ses;
+		sha1_hash h = hasher((char*)&self, sizeof(self))
+			.update((char*)&m_storage, sizeof(m_storage))
+			.update((char*)&ses, sizeof(ses))
+			.final();
+		unsigned char const* ptr = &h[0];
+		return detail::read_uint32(ptr);
+	}
+
 	void torrent::set_piece_deadline(int piece, int t, int flags)
 	{
 		INVARIANT_CHECK;