Libtorrent 0.14 4 download

This defaults to seconds, since that's what's specified in the protocol specification. After half the time out, a keep alive message is sent. This value defaults to 20 seconds. When using persistent connections to HTTP 1.

This number controls the number of outstanding requests to use with url-seeds. Default is 5. The reason why files are left open at all is that some anti virus software hooks on every file close, and scans the file for viruses. Most operating systems also has a limit on the total number of file descriptors a process may have open. It is usually a good idea to find this limit and set the number of connections and the number of files limits so their sum is slightly below it. Multiple connections from the same IP address is not allowed by default, to prevent abusive behavior by peers.

It may be useful to allow such connections in cases where simulations are run on the same machie, and all peers in a swarm has the same IP address. If a peer succeeds, the failcounter is reset. If a peer is retrieved from a peer source other than DHT the failcount is decremented by one, allowing another try.

If the peer fails, the time is multiplied by fail counter. The default is 10 seconds. This setting is especially important in case the number of half-open connections are limited, since stale half-open connection may delay the connection of other peers considerably.

This is typically not necessary, but it might be necessary for collecting statistics in some cases. Default is false. If the client is seed, a few bits will be set to 0, and later filled in with have-messages.

This is to prevent certain ISPs from stopping people from seeding. Default is 10 minutes. This is defined as 30 seconds in the protocol, and it should be significantly longer than what it takes for TCP to ramp up to it's max rate. On this timer, the currently optimistically unchoked peer will change. If left as the default default constructed , that parameter is ommited.

This defaults to 4, which means the 4 first pieces in any torrent are picked at random, the following pieces are picked in rarest first order. This limit is meant to stop fast internet connections to queue up bufferes indefinitely on slow hard-drives or storage.

If no response is received within this time, the connection is closed. If this is true, the DHT will only be used for torrents where all trackers in its tracker list has failed. Either by an explicit error message or a time out. This is false by default, which means the DHT is used by default regardless of if the trackers fail or not.

If it is set to true the hashes are freed once the torrent is a seed they're not needed anymore since the torrent won't download anything more. If it's set to false they are not freed. If set too small, upload rate capacity will suffer.

If set too high, memory will be wasted. The actual watermark may be lower than this in case the upload rate is low, this is the upper limit. If the upload rate has been saturated for an extended period of time, on upload slot is closed. Parole mode means that peers that participate in pieces that fail the hash check are put in a mode where they are only allowed to download whole pieces.

If the whole piece a peer in parole mode fails the hash check, it is banned. If a peer participates in a piece that passes the hash check, it is taken out of parole mode. It is specified in units of 16 KiB blocks. Default is 60 second. This may be useful for users whose router allows them to assign QoS classes to traffic based on its local port. The default value for this is 0x0 no marking.

For more details, see QBSS. Setting the value to -1 means unlimited. Torrents that are not auto managed are also counted against these limits. If there are non-auto managed torrents that use up all the slots, no auto managed torrent will be activated. This is intended to make it more likely to utilize all available bandwidth, and avoid having torrents that don't transfer anything block the active slots. This applies even to slow torrents.

See queuing. For instance if both ends have completed their downloads, there's no point in keeping it open. This defaults to true.

This ratio is used to determine which torrents to seed and which to pause. In case there are a large number of paused auto managed torrents, this puts a limit on how often a scrape request is sent. These peers are not necessarily connected, so this number should be much greater than the maximum number of connected peers. This is specified in seconds, defaults to 5 minutes and is used as a sanity check on what is returned from a tracker. It mitigates hammering misconfigured trackers. If false, rare pieces are always prioritized, unless the number of partial pieces is growing out of proportion.

This is so that newly started torrents are not considered inactive until they have a fair chance to start downloading.

The settings for these are:. This setting will adjust which encryption scheme is offered to the other peer, as well as which encryption scheme is selected by the client. The settings are:. If required, username and password can be set to authenticate with the proxy. The type tells libtorrent what kind of proxy server it is. The following options are available:. The default constructor creates a single rule that allows all addresses 0.

Adds a rule to the filter. Returns the access permissions for the given address addr. The complexity of this operation is O log n , where n is the minimum number of non-overlapping ranges to describe the current filter.

This function will return the current state of the filter in the minimum number of ranges possible. They are sorted from ranges in low addresses to high addresses. Each entry in the returned vector is a range with the access control specified in its flags field. The return value is a tuple containing two range-lists. One for IPv4 addresses and one for IPv6 addresses. It represents 20 bytes of data. Its synopsis follows:. You use it by first instantiating it, then call update to feed it with data.

You can feed the hasher parts of it at a time. When You have fed the hasher with all the data, you call final and it will return the sha1-hash of the data. If you want to reuse the hasher object once you have created a hash, you have to call reset to reinitialize it. The sha1-algorithm used was implemented by Steve Reid and released as public domain. The fingerprint class represents information about a client and its version.

It is used to encode this information into the client's peer id. These are the characters that should be unique for your client. Make sure not to clash with anybody else. Here are some taken id's:.

There's currently an informal directory of client id's here. The major , minor , revision and tag parameters are used to identify the version of your client. All these numbers must be within the range [0, 9]. Attempts to add a port mapping for the specified protocol. This is a hint, you are not guaranteed that this port will be available, and it may end up being something else. The return value is an index that identifies this port mapping. If The mapping fails immediately, the return value is -1, which means failure.

There will not be any error alert notification for mappings that fail with a -1 return value. This function removes a port mapping. This is only available for UPnP routers. If the model is advertized by the router, it can be queried through this function.

It can can be used to extract a string describing a client version from its peer-id. It will recognize most clients that have this kind of identification in the peer-id.

Returns an optional fingerprint if any can be identified from the peer id. This can be used to automate the identification of clients. It will not be able to identify peers with non- standard encodings.

Only Azureus style, Shadow's style and Mainline style. These functions will encode data to bencoded or decode bencoded data.

The entry class is the internal representation of the bencoded data and it can be used to retrieve information, an entry can also be build by the program and given to bencode to encode it into the OutIt iterator. These functions will assume that the iterator refers to a character char. So, if you want to encode entry e into a buffer in memory, you can do it like this:.

Now we just need to know how to retrieve information from the entry. This function parses the magnet URI uri as a bittorrent magnet link, and adds the torrent to the specified session ses.

It returns the handle to the newly added torrent, or an invalid handle in case parsing failed. For more information about magnet links, see magnet links. Generates a magnet URI from the specified torrent. If the torrent handle is invalid, an empty string is returned. If there is an alert in libtorrent's queue, the alert from the front of the queue is popped and returned. You can then use the alert object and query. By default, only errors are reported.

The alert mask is a bitmask with the following bits:. Every alert belongs to one or more category. There is a small cost involved in posting alerts.

Only alerts that belong to an enabled category are posted. Setting the alert bitmask to 0 will disable all alerts. You can also use a dispatcher mechanism that's available in libtorrent. The alert class is the base class that specific messages are derived from. It does not include any information that might be bundled with the alert. This is mainly intended for debug and development use. It is not suitable to use this for applications that may be localized. Instead, handle each alert type individually and extract and render the information from the alert depending on the locale.

There's another alert base class that most alerts derives from, all the alerts that are generated for a specific torrent are derived from:. Whenever libtorrent learns about the machines external IP, this alert is generated. The external IP address can be acquired from the tracker if it supports that or from peers that supports the extension protocol.

This alert is generated when none of the ports, given in the port range, to session can be opened for listening. Port 0 asks the operating system to pick a port that's free. This alert is generated when a NAT router was successfully found but some part of the port mapping request failed.

It contains a text message that may help the user figure out what is wrong. This alert is not generated in case it appears the client is not running on a NAT:ed network or if it appears there is no NAT router that can be remote controlled to add port mappings.

This alert is generated when a NAT router was successfully found and a port was successfully mapped on it. If the storage fails to read or write files that it needs access to, this alert is generated and the torrent is paused. The index member refers to the index of the file that was renamed, name is the new name of the file. The index member refers to the index of the file that was supposed to be renamed, msg is the error message returned from the filesystem.

This alert is generated each time a tracker announce is sent or attempted to be sent. There are no extra data members in this alert. The url can be found in the base class however. This alert is generated on tracker time outs, premature disconnects, invalid response or a HTTP response other than " OK". From the alert you can get the handle to the torrent the tracker belongs to.

If the tracker timed out, the code will be set to 0. This alert is only for informational purpose. It is generated when a tracker announce succeeds. This is not necessarily all new peers, some of them may already be connected.

This alert is generated each time the DHT receives peers from a node. Typically these packets are received from multiple DHT nodes, and so the alerts are typically generated a few at a time. This alert is triggered if the tracker reply contains a warning field. Usually this means that the tracker announce was successful, but the tracker has a message to the client.

The msg string in the alert contains the warning message from the tracker. This alert is generated when a scrape request succeeds. These numbers may be -1 if the reponse was malformed.

If a scrape request fails, this alert is generated. This might be due to the tracker timing out, refusing connection or returning an http response code indicating an error. It contains url to the HTTP seed that failed along with an error message. This alert is generated when a finished piece fails its hash check. You can get the handle to the torrent which got the failed piece and the index of the piece itself from the alert. This alert is generated when a peer is banned because it has sent too many corrupt pieces to us.

This alert is generated when a peer sends invalid data over the peer-peer protocol. The peer will be disconnected, but you get its ip address from the alert, to identify it. This is a debug alert that is generated by an incoming invalid piece request. This alert is generated when a torrent switches from being a downloader to a seed. It will only be generated once per torrent. This alert is generated when a limit is reached that might have a negative impact on upload or download rate performance.

This alert is generated when the metadata has been completely received and the info-hash failed to match it. This is only relevant when running a torrent-less download, with the metadata extension provided by libtorrent. This alert is generated when the metadata has been completely received and the torrent can start downloading.

It is not generated on torrents that are started with metadata, but only those that needs to download it from peers when utilizing the libtorrent extension. The string explains the reason why the resume file was rejected. This alert is generated when a peer is blocked by the IP filter. The ip member is the address that was blocked. This is useful to synchronize with the actual disk.

The path member is the new path of the storage. It is generated once all disk IO is complete and the files in the torrent have been closed. This is useful for synchronizing with the disk. It is generated when a torrent goes from a paused state to an active state. It is generated once the disk IO thread is done writing the state for this torrent. In this example 3 alert types are used. You can use any number of template parameters to select between more types.

There are a number of exceptions that can be thrown from different places in libtorrent, here's a complete list with description. This is thrown by bdecode if the input data is not a valid bencoding. This is thrown from the accessors of entry if the data type of the entry doesn't match the type you want to extract from it.

The storage interface is a pure virtual class that can be implemented to customize how and where data for a torrent is stored.

The default storage implementation uses regular files in the filesystem, mapping the files in the torrent in the way one would assume a torrent is saved to disk. It is also possible to write a thin class that uses the default storage but modifies some particular behavior, for instance encrypting the data before it's written to disk, and decrypting it when it's read again.

All access is done by writing and reading whole or partial slots. One slot is one piece in the torrent, but the data in the slot does not necessarily correspond to the piece with the same index in compact allocation mode it won't.

This function is called when the storage is to be initialized. The default storage will create directories and empty files at this point. Returning true indicates an error occurred. This function is called when first checking or re-checking the storage for a torrent. It should return true if any of the files that is used in this storage exists on disk.

If so, the storage will be checked for existing pieces before starting the download. This function should read the data in the given slot and at the given offset and size number of bytes. The data is to be copied to buf. This function should write the data in buf to the given slot slot at offset offset in that slot. The buffer size is size. The default storage moves the single file or the directory of the torrent.

Returning false indicates an error occurred. This function should verify the resume data rd with the files on disk. If the resume data seems to be up-to-date, return true. If not, set error to a description of what mismatched and return false. This function should fill in resume data, the current state of the storage, in rd. The default storage adds file timestamps and sizes. This is only used in compact mode. If the storage caches slots, this could be implemented more efficient than reading and writing the data.

This function should swap the data in slot1 and slot2. The default storage uses a scratch buffer to read the data into, then moving the other slot and finally writing back the temporary slot's data. This function should do a 3-way swap, or shift of the slots.

If there is an error, true should be returned. This function should release all the file handles that it keeps open to files belonging to this storage. Magnet links are URIs that includes an info-hash, a display name and optionally a tracker url.

The idea behind magnet links is that an end user can click on a link in a browser and have it handled by a bittorrent application, to start a download, without any. Which means it makes sure that a limited number of torrents are being downloaded at any given time, and once a torrent is completely downloaded, the next in line is started. Torrents that are auto managed are subject to the queuing and the active torrents limits. These limits takes non auto managed torrents into account as well.

At a regular interval, torrents are checked if there needs to be any re-ordering of which torrents are active and which are queued. It defaults to every 30 seconds. For queuing to work, resume data needs to be saved and restored for all torrents. Torrents that are currently being downloaded or incomplete with bytes still to download are queued. The torrents in the front of the queue are started to be actively downloaded and the rest are ordered with regards to their queue position.

Any newly added torrent is placed at the end of the queue. Once a torrent is removed or turns into a seed, its queue position is -1 and all torrents that used to be after it in the queue, decreases their position in order to fill the gap. Lower queue position means closer to the front of the queue, and will be started sooner than torrents with higher queue positions.

Auto managed seeding torrents are rotated, so that all of them are allocated a fair amount of seeding. Torrents with fewer completed seed cycles are prioritized for seeding.

The fast resume mechanism is a way to remember which pieces are downloaded and where they are put between sessions. You can then save this data to disk and use it when resuming the torrent. The fast-resume data also contains information about which blocks, in the unfinished pieces, were downloaded, so it will not have to start from scratch on the partially downloaded pieces. It may have to do the checking anyway, if the fast-resume data is corrupt or doesn't fit the storage for that torrent, then it will not trust the fast-resume data and just do the checking.

The list maps slots to piece indices. It tells which piece is on which slot. If piece index is -2 it means it is free, that there's no piece there. If it is -1, means the slot isn't allocated on disk yet. The pieces have to meet the following requirement:.

If there's a slot at the position of the piece index, the piece must be located in that slot. These are the local peers we were connected to when this fast-resume data was saved.

Each dictionary represents an piece, and has the following layout:. The allocation mode is selected when a torrent is started. The decision to use full allocation or compact allocation typically depends on whether any files are filtered and if the filesystem supports sparse files.

On filesystems that supports sparse files, this allocation mode will only use as much space as has been downloaded. When a torrent is started in full allocation mode, the disk-io thread see threads will make sure that the entire storage is allocated, and fill any gaps with zeros. This will be skipped if the filesystem supports sparse files or automatic zero filling.

It will of course still check for existing pieces and fast resume data. The main drawbacks of this mode are:. The compact allocation will only allocate as much storage as it needs to keep the pieces downloaded so far. This means that pieces will be moved around to be placed at their final position in the files while downloading to make sure the completed download has all its pieces in the correct place.

So, the main drawbacks are:. The algorithm that is used when allocating pieces and slots isn't very complicated. For the interested, a description follows. These extensions all operates within the extension protocol. The name of the extension is the name used in the extension-list packets, and the payload is the data in the extended message not counting the length-prefix, message-id nor extension-id.

Note that since this protocol relies on one of the reserved bits in the handshake, it may be incompatible with future versions of the mainline bittorrent client. The point with this extension is that you don't have to distribute the metadata. The metadata can be distributed through the bittorrent swarm.

The only thing you need to download such a torrent is the tracker url and the info-hash of the torrent. It works by assuming that the initial seeder has the metadata and that the metadata will propagate through the network as more peers join.

There are three kinds of messages in the metadata extension. These packets are put as payload to the extension message. The three packets are:. The HTTP seed extension implements this specification.

The way this works is that if the torrent is a single-file torrent, only that filename is appended. This is the same directory structure that libtorrent will download torrents into. Filesystem will by default check all its paths to make sure they conform to filename requirements on many platforms.

If you don't want this check, you can set it to either only check for native filesystem requirements or turn it off altogether. You can use:. For more information, see the Boost. Filesystem docs. Home Products Contact.

Rasterbar Software Software developement and consulting. The using statements will give easy access to: tcp::endpoint udp::endpoint Which are the endpoint types used in libtorrent. This is the recommended, and default mode. For filesystem that supports sparse files, this is in all practical aspects identical to sparse mode.

For filesystems that don't, it will allocate the data for the files. The main plugins implemented in libtorrent are: metadata extension Allows peers to download the metadata. Makes it possible to join a swarm with just a tracker and info-hash. Should eliminate most problems on poisoned torrents. The dht node state is a bencoded dictionary with the following entries: nodes A list of strings, where each string is a node endpoint encoded in binary. If the string is 6 bytes long, it is an IPv4 address of 4 bytes, encoded in network byte order big endian , followed by a 2 byte port number also network byte order.

If the string is 18 bytes long, it is 16 bytes of IPv6 address followed by a 2 bytes port number also network byte order. It is turned off by default. It is off by default. See HTTP seeding for more information.

Both the name and the comment is UTF-8 encoded strings. There are 8 different priority levels: piece is not downloaded at all normal priority. Download order is dependent on availability higher than normal priority. Pieces are preferred over pieces with the same availability, but not over pieces with lower availability pieces are as likely to be picked as partial pieces. The fast resume data will be empty in the following cases: The torrent handle is invalid. The torrent is checking or is queued for checking its storage, it will obviously not be ready to write resume data.

The torrent hasn't received valid metadata and was started without metadata see libtorrent's metadata from peers extension Note that by the time you receive the fast resume data, it may already be invalid if the torrent is still downloading! Warning If you pause every torrent individually instead of pausing the session, every torrent will have its paused state saved in the resume data! Note It is typically a good idea to save resume data whenever a torrent is completed or paused.

Each block has a state state which is any of: none - This block has not been downloaded or requested form any peer. But there currently is another torrent that are being checked. This torrent will wait for its turn. This is the state most torrents will be in most of the time. The progress meter will tell how much of the files that has been downloaded. The following table describes each flag: interesting we are interested in pieces from this peer. If this flag is not set, this peer connection was opened by this peer connecting to us.

Until the handshake is done, the peer cannot be identified. This may happen if there is a limit set on the number of half-open TCP connections. If it doesn't within some period of time, it will be choked and another peer will be optimistically unchoked. We're currently picking one block at a time from this peer. The flags are: tracker The peer was received from the tracker. This is the state all peers are in if there are no bandwidth limits.

The settings for these are: forced - Only encrypted connections are allowed. Incoming connections that are not encrypted are closed and if the encrypted outgoing connection fails, a non-encrypted retry will not be made.

An incoming non-encrypted connection will be accepted, and if an outgoing encrypted connection fails, a non- encrypted connection will be tried. The settings are: plaintext - only the handshake is encrypted, the bulk of the traffic remains unchanged.

The following options are available: none - This is the default, no proxy server is used, all other fields are ignored. The username and password are ignored. The username and password specified may be sent to the proxy if it requires. The proxy is assumed to not require authorization. The username and password will not be used. The username and password will be sent to the proxy.

You can then use the alert object and query By default, only errors are reported. This includes: tracker errors tracker warnings file errors resume data failures web seed errors.

File errors and synchronization events for moving the storage, renaming files etc. Includes announcing to trackers, receiving responses, warnings and errors. Also when pieces are completed. It is defined as: None Completed Started Stopped. There are no additional data members in this alert.

The return value is the number of bytes actually read. The return value is the number of bytes actually written. The default storage may compare file sizes and time stamps of the files. The default storage uses a scratch buffer to read the data into, then moving the other slot and finally writing back the temporary slot's data This is only used in compact mode.

The function should return the hash of the piece stored in the slot. The format of the magnet URI is: magnet:? The default values are 8 active downloads and 5 active seeds. The queue positions are always in a sequence without any gaps. Clamped to be within the range [1, ]. It is the number of blocks per normal sized piece. But if piece size is greater than 4 megabytes, the block size will increase.

Bit 1 means we have that piece. The pieces have to meet the following requirement: If there's a slot at the position of the piece index, the piece must be located in that slot.

Each dictionary has the following layout: ip string, the ip address of the peer. This is not a binary representation of the ip address, but the string representation.

It may be an IPv6 string or an IPv4 string. Each dictionary represents an piece, and has the following layout: piece integer, the index of the piece this entry refers to. Each entry has a list of two values, the first value is the size of the file in bytes, the second is the time stamp when the last time someone wrote to it.

This information is used to compare with the files on disk. All the files must match exactly this information in order to consider the resume data as current.

Otherwise a full re-check is issued. Can be either full or compact. If this is full, the file sizes and timestamps are disregarded. Pieces are assumed not to have moved around even if the files have been modified after the last resume data checkpoint. The first thread is the main thread that will sit idle in a select call most of the time.

This thread runs the main loop that will send and receive data on all connections. All disk read and write operations are passed to this thread and messages are passed back to the main thread when the operation completes. The disk thread also verifies the piece hashes. The third and forth threads are spawned by asio on systems that don't support non-blocking host name resolution to simulate non-blocking getaddrinfo.

The traditional full allocation mode, where the entire files are filled up with zeros before anything is downloaded. This means that on NTFS, full allocation mode will only allocate storage for the downloaded pieces. The compact allocation mode, where only files are allocated for actual pieces that have been downloaded.

The sparse allocation , sparse files are used, and pieces are downloaded directly to where they belong. This is the recommended and default mode. It does not require an allocation pass on startup. It supports skipping files setting prioirty to 0 to not download. Fast resume data will remain valid even when file time stamps are out of date.

The main drawbacks of this mode are: It may take longer to start the torrent, since it will need to fill the files with zeros on some systems. This delay is linearly dependent on the size of the download.

The download may occupy unnecessary disk space between download sessions. In case sparse files are not supported. Disk caches usually perform extremely poorly with random access to large files and may slow down a download considerably.

The benefits of this mode are: Downloaded pieces are written directly to their final place in the files and the total number of disk operations will be fewer and may also play nicer to filesystems' file allocation, and reduce fragmentation.

No risk of a download failing because of a full disk during download. Unless sparse files are being used. The fast resume data will be more likely to be usable, regardless of crashes or out of date data, since pieces won't move around. Can be used with the filter files feature. So, the main drawbacks are: More disk operations while downloading since pieces are moved around.

Potentially more fragmentation in the filesystem. Cannot be used while filtering files. The benefits though, are: No startup delay, since the files doesn't need allocating. The download will not use unnecessary disk space.

Disk caches perform much better than in full allocation and raises the download speed limit imposed by the disk. Works well on filesystems that doesn't support sparse files.

These are the extensions that are currently implemented. It is given in ths of the total size of the metadata, since the requesting client don't know the size of the metadata. This is also given in ths of the total size of the metadata.

The size is given as size The BitTorrent specification states that in Multiple File Mode the filename path is: a list containing one or more string elements that together represent the path and filename. Each element in the list corresponds to either a directory name or in the case of the final element the filename.

Line will add any further path components to the overloaded one, thus constructing a path that may point to any file location that is accessible via a relative path e.

The attacker may use such paths in specially crafted. Furthermore, because of the way the Multiple File Mode works, any directories referrenced by these malicious torrent files e. The maintainer of libtorrent has been contacted and a new version of the library 0.