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PageKite API reference manual

Functions

Initialization

pagekite_mgr pagekite_init(...)

Initialize the PageKite manager.

This allocates a static amount of RAM for PageKite (not counting buffers managed by OpenSSL). Since libpagekite's resource usage is allocated up-front, you need to specify maximum numbers of kites, front-end relays and in-flight connections you want to keep track of at any one time.

The flags variable should be used with the constants PK_WITH_* and PK_AS_*, bitwise OR'ed together to tune the behaviour of libpagekite. To use the recommended defaults, simply specify PK_WITH_DEFAULTS. Requesting defaults is a forward compatible choice and will continue to use recommended settings even as new features are added to the library.

The verbosity argument controls the internal logging. A small integer (-1, 0, 1, 2) can be used to choose from a predefined level, for more fine-grained control use the PK_LOG_ constants bitwise OR'ed together to enable logging of individual subsystems.

This method can only be called before starting the master thread.

Arguments:

  • const char* app_id: Short ID, reported in instrumentation
  • int max_kites: Max number of kite names allowed
  • int max_frontends: Max number of front-end relays recognized
  • int max_conns: Max number of in-flight connections
  • const char* dyndns_url: Dynamic DNS update URL (format string)
  • int flags: Flags, which features to enable
  • int verbosity: Verbosity or log mask

Returns: A reference to the PageKite manager object.

pagekite_mgr pagekite_init_pagekitenet(...)

Initialize the PageKite manager, configured for use with the pagekite.net public service.

See the basic init docs for further details.

If flags do not include PK_WITHOUT_SERVICE_FRONTENDS, service frontends will be chosen automatically using the given domain name.

This method can only be called before starting the master thread.

Arguments:

  • const char* app_id: Short ID, reported in instrumentation
  • int max_kites: Max number of kite names allowed
  • int max_conns: Max number of in-flight connections
  • int flags: Flags, which features to enable
  • int verbosity: Verbosity or log mask

Returns: A reference to the PageKite manager object.

pagekite_mgr pagekite_init_whitelabel(...)

Initialize the PageKite manager, configured for use with a pagekite.net white-label domain.

See the basic init docs for further details.

If flags do not include PK_WITHOUT_SERVICE_FRONTENDS, white-label frontends will be chosen automatically using the given domain name.

This method can only be called before starting the master thread.

Arguments:

  • const char* app_id: Short ID, reported in instrumentation
  • int max_kites: Max number of kite names allowed
  • int max_conns: Max number of in-flight connections
  • int flags: Flags, which features to enable
  • int verbosity: Verbosity or log mask
  • const char* whitelabel_tld: Top level domain of white-label kites

Returns: A reference to the PageKite manager object.

int pagekite_add_kite(...)

Configure a "kite", mapping a public domain to a local service.

Multiple kites can be configured for the same domain name, by calling this function multiple times, as long as the public port or protocol differ.

This method can only be called before starting the master thread.

Note: When used with the "raw" protocol, the public port cannot be 0.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • const char* proto: Protocol
  • const char* kitename: Kite DNS name
  • int pport: Public port, 0 for default/any
  • const char* secret: Kite secret for authentication
  • const char* backend: Hostname of the origin server
  • int lport: Port of the origin server

Returns: 0 on success, -1 on failure.

int pagekite_add_service_frontends(...)

Configure libpagekite to use the Pagekite.net pool of public front-end relay servers.

This method can only be called before starting the master thread.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int flags: Flags to enable IPv4, IPv6 and/or dynamic frontends

Returns: The number of relay IPs configured, or -1 on failure.

int pagekite_add_whitelabel_frontends(...)

Configure libpagekite to use the relays associated with a Pagekite.net white-label domain.

This method can only be called before starting the master thread.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int flags: Flags to enable IPv4, IPv6 and/or dynamic frontends
  • const char* whitelabel_tld: Top level domain of white-label kites

Returns: The number of relay IPs configured, or -1 on failure.

int pagekite_lookup_and_add_frontend(...)

Configure libpagekite front-end relays.

All available IP addresses referenced by the specified DNS name will be configured as potential relays, and the app will choose between them based on performance metrics.

If update_from_dns is nonzero, DNS will be rechecked periodically for new relay IPs. Enabling such updates is generally preferred over a completely static configuration, so long-running instances can keep up with changes to the relay infrastructure.

This method can only be called before starting the master thread.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • const char* domain: DNS name of the frontend (or pool of frontends)
  • int port: Port to connect to
  • int update_from_dns: Set nonzero to re-lookup periodically from DNS

Returns: The number of relay IPs configured, or -1 on failure.

int pagekite_add_frontend(...)

Configure libpagekite front-end relays.

All available IP addresses referenced by the specified DNS name will be configured as potential relays, and the app will choose between them based on performance metrics.

This method is static - DNS is only checked on startup. This is not optimal and this method is only provided for backwards compatibility. New apps should enable periodic DNS updates.

This method can only be called before starting the master thread.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • const char* domain: DNS name of the frontend (or pool of frontends)
  • int port: Port to connect to

Returns: The number of relay IPs configured, or -1 on failure.

int pagekite_set_log_mask(...)

Configure the log verbosity using a bitmask.

See the PK_LOG_* constants for options.

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int mask: A bitmask

Returns: Always returns 0.

int pagekite_set_log_destination(...)

Configure log destination.

This function can be called at any time. The argument should be either a file descriptor (integer >= 0) or one of the constants PK_LOG_DEST_SYSLOG or PK_LOG_DEST_NONE.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int log_destination: Log destination

Returns: Always returns 0.

int pagekite_set_housekeeping_min_interval(...)

Configure the minimum interval for internal housekeeping.

Internal housekeeping includes attempting to re-establish a connection to the required relays, occasionally refreshing information from DNS and pinging tunnels to detect whether they have gone silently dead (due to NAT timeouts, for example).

Setting this interval too low may reduce battery life or increase load on shared infrastructure, as a result there is a hard-coded minimum value which this function cannot override. Setting this interval too high may prevent libpagekite from detecting network outages and recovering in a timely fashion.

The app will by default choose an interval between the minimum and maximum as appropriate. Most apps will not need to change this setting.

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int interval: Interval, in seconds

Returns: The new minimum housekeeping interval.

int pagekite_set_housekeeping_max_interval(...)

Configure the maximum interval for internal housekeeping.

See the documentation for the minimum housekeeping interval for details and performance concerns.

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int interval: Interval, in seconds

Returns: The new maximum housekeeping interval.

int pagekite_set_rejection_url(...)

Configure the rejection URL.

See the destination URL included in the IFRAME for incoming requests that cannot be handled (e.g. because the origin web server is down or things are misconfigured).

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • const char* url: The new URL

Returns: 0

int pagekite_enable_http_forwarding_headers(...)

Enable or disable HTTP forwarding headers.

When enabled, libpagekite will rewrite incoming HTTP headers to add information about the remote IP address and remote protocol.

The X-Forwarded-For header will contain the IP address of the remote HTTP client, as reported by the front-end relay (probably in IPv6 notation).

The X-Forwarded-Proto header will report whether the connection to the relay was HTTP or HTTPS. This can be detected and used to redirect or reject plain-text connections.

Limitations: Headers are only added to the first request of a persistent HTTP/1.1 session. The data reported comes from the front-end relay and a malicious relay could provide false data.

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int enable: 0 disables, any other value enables

Returns: Always returns 0.

int pagekite_enable_fake_ping(...)

Enable or disable fake pings.

This is a debugging/testing option, which effectively randomizes which front-end relay is used and increases the frequency of migrations.

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int enable: 0 disables, any other value enables

Returns: Always returns 0.

int pagekite_enable_watchdog(...)

Enable or disable watchdog.

The watchdog is a thread which periodically checks if the main pagekite thread has locked up. If it thinks the app has locked up, it will cause a segmentation fault, which in turn will create a core dump for debugging (assuming ulimits allow).

This method can only be called before starting the master thread.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int enable: 0 disables, any other value enables

Returns: Always returns 0.

int pagekite_enable_tick_timer(...)

Enable or disable tick event timer.

This method can be used to toggle the tick event timer on or off (it is on by default). Apps may want to disable the timer for power saving reasons.

If the timer is disabled, the tick method should be called instead when possible, to ensure that housekeeping takes place.

This method may be called at any time, but may hang as it waits for the main event-loop lock.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int enable: 0 disables, any other value enables

Returns: Always returns 0.

int pagekite_set_conn_eviction_idle_s(...)

Configure eviction of idle connections.

As libpagekite works with a fixed pool of RAM, it may be unable to allocate buffers for new incoming connections. When this happens, the oldest connection which has been idle for more than seconds seconds may be evicted.

Set seconds = 0 to disable eviction and instead reject incoming connections when overloaded. Eviction is disabled by default.

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int seconds: Minimum idle time to qualify for eviction

Returns: Always returns 0.

int pagekite_set_openssl_ciphers(...)

Choose which ciphers to use in TLS

See the SSL_set_cipher_list(3) and ciphers(1) man pages for details.

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • const char* ciphers: The string passed to OpenSSL

Returns: Always returns 0.

int pagekite_want_spare_frontends(...)

Connect to multiple front-end relays.

If non-zero, this setting will configure how many spare relays to connect to at any given time. This may increase availability or performance in some special cases, but increases the load on shared relay infrastructure and should be avoided if possible.

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int spares: Number of spare front-ends to connect to

Returns: Always returns 0.

Lifecycle

int pagekite_thread_start(...)

Start the main thread: run pagekite!

This function should only be called once (per session).

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object

Returns: The return value of pthread_create()

int pagekite_thread_wait(...)

Wait for the main pagekite thread to finish.

This function should only be called once (per session). Running this function will implicitly respond to all API events with PK_EV_RESPOND_DEFAULT.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object

Returns: The return value of pthread_join()

int pagekite_thread_stop(...)

Stop the main pagekite thread.

This function should only be called once (per session).

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object

Returns: The return value of pthread_join()

int pagekite_free(...)

Free the internal libpagekite buffers.

Call this to free any memory allocated by the init functions.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object

Returns: 0 on success, -1 on failure.

int pagekite_set_event_mask(...)

Configure which API events we are interested in.

This function will change the event mask to enable or disable posting of API events. This can be called at any time, but if events outside the mask have already been posted (but not handled) they will not be not function.

See also: doc/Event_API.md

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • unsigned int mask: A bitmask describing which events we want

Returns: Always returns 0.

unsigned int pagekite_await_event(...)

Wait for a libpagekite event.

This function blocks until one of the libpagekite worker threads posts an API event.

See also: doc/Event_API.md

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int timeout: Max seconds to wait for an event

Returns: An integer code identifying the event.

int pagekite_get_event_int(...)

Get event data (integer).

This function returns the integer data associated with a given API event.

See also: doc/Event_API.md

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • unsigned int event_code: The code identifying the event

Returns: An integer.

const char* pagekite_get_event_str(...)

Get event data (string).

This function returns a pointer to the data associated with a given API event.

See also: doc/Event_API.md

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • unsigned int event_code: The code identifying the event

Returns: A pointer to a string.

int pagekite_event_respond(...)

Respond to a pagekite event.

Post a response to an API event.

See also: doc/Event_API.md

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • unsigned int event_code: The event code
  • unsigned int response_code: Our response

Returns: Always returns 0.

int pagekite_event_respond_with_data(...)

Respond to a pagekite event.

Post a response (with data) to an API event.

See also: doc/Event_API.md

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • unsigned int event_code: The event code
  • unsigned int response_code: Our response
  • int response_int: Integer response data
  • const char* response_str: String response data (or NULL)

Returns: Always returns 0.

int pagekite_get_status(...)

Get the current status of the app.

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object

Returns: A PK_STATUS_* code.

char* pagekite_get_log(...)

Fetch the in-memory log buffer.

Note that the C-API version returns a pointer to a static buffer. Subsequent calls will overwrite with new data.

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object

Returns: A snapshot of the current log status.

int pagekite_dump_state_to_log(...)

Dump summary of internal state to log.

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object

Returns: Always returns 0.

int pagekite_poll(...)

Wait for the pagekite event loop to wake up.

This method can be used to pause a thread, waking up again when libpagekite status changes, network activity takes place or other events take place which might affect the log or state variable.

This method can be called any time the main thread is running.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int timeout: Max time to wait, in seconds

Returns: 0 on success, -1 if unconfigured.

int pagekite_tick(...)

Manually trigger the internal tick event.

The internal tick event may trigger housekeeping if necessary.

This method is only needed if the internal periodic timer has been disabled (e.g. on a mobile app, to conserve battery life).

This method can be called any time the main thread is running.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object

Returns: 0 on success, -1 if unconfigured.

int pagekite_set_bail_on_errors(...)

Enable or disable bailing out on errors.

If enabled, the app will increase log verbosity and finally call exit(100) after too many errors have occurred. This can help catch and handle error states, but care should be taken as it will also bring down the hosting app.

The sensitivity of this function depends on the errors variable. After errors * 9 problems would have been logged, verbosity is increased. After errors * 10, the app will exit.

This function can be called at any time.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • int errors: An error threshold

Returns: Always returns 0.

int pagekite_perror(...)

Log an error and reset the internal error state.

Arguments:

  • pagekite_mgr: A reference to the PageKite manager object
  • const char* prefix: Prefix for the logged message

Returns: Always returns 0.

Constants

PK_VERSION = "0.91.180519C"
PK_STATUS_STARTUP = 10
PK_STATUS_CONNECTING = 20
PK_STATUS_UPDATING_DNS = 30
PK_STATUS_FLYING = 40
PK_STATUS_PROBLEMS = 50
PK_STATUS_REJECTED = 60
PK_STATUS_NO_NETWORK = 90
PK_WITH_DEFAULTS = 0x8000
PK_WITHOUT_DEFAULTS = 0x4000
PK_WITH_SSL = 0x0001
PK_WITH_IPV4 = 0x0002
PK_WITH_IPV6 = 0x0004
PK_WITH_SERVICE_FRONTENDS = 0x0008
PK_WITHOUT_SERVICE_FRONTENDS = 0x0010
PK_WITH_DYNAMIC_FE_LIST = 0x0020
PK_WITH_FRONTEND_SNI = 0x0040
PK_WITH_SRAND_RESEED = 0x0080
PK_AS_FRONTEND_RELAY = 0x0100
PK_WITH_SYSLOG = 0x0200
PK_LOG_TUNNEL_DATA = 0x000100
PK_LOG_TUNNEL_HEADERS = 0x000200
PK_LOG_TUNNEL_CONNS = 0x000400
PK_LOG_BE_DATA = 0x001000
PK_LOG_BE_HEADERS = 0x002000
PK_LOG_BE_CONNS = 0x004000
PK_LOG_MANAGER_ERROR = 0x010000
PK_LOG_MANAGER_INFO = 0x020000
PK_LOG_MANAGER_DEBUG = 0x040000
PK_LOG_TRACE = 0x080000
PK_LOG_ERROR = 0x100000
PK_LOG_ERRORS = (PK_LOG_ERROR|PK_LOG_MANAGER_ERROR)
PK_LOG_MANAGER = (PK_LOG_MANAGER_ERROR|PK_LOG_MANAGER_INFO)
PK_LOG_CONNS = (PK_LOG_BE_CONNS|PK_LOG_TUNNEL_CONNS)
PK_LOG_NORMAL = (PK_LOG_ERRORS|PK_LOG_CONNS|PK_LOG_MANAGER)
PK_LOG_HEADERS = (PK_LOG_NORMAL|PK_LOG_TUNNEL_HEADERS|PK_LOG_BE_HEADERS)
PK_LOG_DATA = (PK_LOG_HEADERS|PK_LOG_TUNNEL_DATA|PK_LOG_BE_DATA)
PK_LOG_DEBUG = (PK_LOG_DATA|PK_LOG_MANAGER_DEBUG)
PK_LOG_ALL = 0xffff00
PK_LOG_DEST_SYSLOG = -1
PK_LOG_DEST_NONE = -2
PK_EV_ALL = 0xff000000
PK_EV_IS_BLOCKING = 0x80000000
PK_EV_PROCESSING = 0x40000000
PK_EV_MASK_ALL = 0x3f000000
PK_EV_MASK_LOGGING = 0x01000000
PK_EV_MASK_STATS = 0x02000000
PK_EV_MASK_CONN = 0x04000000
PK_EV_MASK__UNUSED__ = 0x08000000
PK_EV_MASK_DATA = 0x10000000
PK_EV_MASK_MISC = 0x20000000
PK_EV_SLOT_MASK = 0x00ff0000
PK_EV_SLOT_SHIFT = 16
PK_EV_SLOTS_MAX = 0x0100
PK_EV_TYPE_MASK = 0x3f00ffff
PK_EV_NONE = 0x00000000
PK_EV_SHUTDOWN = (0x00000001 | PK_EV_MASK_ALL)
PK_EV_LOGGING = (0x00000002 | PK_EV_MASK_LOGGING)
PK_EV_COUNTER = (0x00000003 | PK_EV_MASK_STATS)
PK_EV_CFG_FANCY_URL = (0x00000004 | PK_EV_MASK_MISC)
PK_EV_TUNNEL_REQUEST = (0x00000005 | PK_EV_MASK_MISC)
PK_EV_RESPOND_DEFAULT = 0x00000000
PK_EV_RESPOND_TRUE = 0x000000ff
PK_EV_RESPOND_OK = 0x00000001
PK_EV_RESPOND_ACCEPT = 0x00000002
PK_EV_RESPOND_FALSE = 0x0000ff00
PK_EV_RESPOND_ABORT = 0x00000100
PK_EV_RESPOND_REJECT = 0x00000200