relay.c File Reference

Handle relay cell encryption/decryption, plus packaging and receiving from circuits, plus queuing on circuits. More...

#include "core/or/or.h"
#include "feature/client/addressmap.h"
#include "lib/err/backtrace.h"
#include "lib/buf/buffers.h"
#include "core/or/channel.h"
#include "feature/client/circpathbias.h"
#include "core/or/circuitbuild.h"
#include "core/or/circuitlist.h"
#include "core/or/circuituse.h"
#include "core/or/circuitpadding.h"
#include "core/or/extendinfo.h"
#include "lib/compress/compress.h"
#include "app/config/config.h"
#include "core/mainloop/connection.h"
#include "core/or/connection_edge.h"
#include "core/or/connection_or.h"
#include "feature/control/control_events.h"
#include "lib/crypt_ops/crypto_rand.h"
#include "lib/crypt_ops/crypto_util.h"
#include "feature/dircommon/directory.h"
#include "feature/relay/dns.h"
#include "feature/relay/circuitbuild_relay.h"
#include "feature/stats/geoip_stats.h"
#include "feature/hs/hs_cache.h"
#include "core/mainloop/mainloop.h"
#include "feature/nodelist/networkstatus.h"
#include "feature/nodelist/nodelist.h"
#include "core/or/onion.h"
#include "core/or/policies.h"
#include "core/or/reasons.h"
#include "core/or/relay.h"
#include "core/crypto/relay_crypto.h"
#include "feature/rend/rendcommon.h"
#include "feature/nodelist/describe.h"
#include "feature/nodelist/routerlist.h"
#include "core/or/scheduler.h"
#include "feature/hs/hs_metrics.h"
#include "feature/stats/rephist.h"
#include "core/or/cell_st.h"
#include "core/or/cell_queue_st.h"
#include "core/or/cpath_build_state_st.h"
#include "feature/dircommon/dir_connection_st.h"
#include "core/or/destroy_cell_queue_st.h"
#include "core/or/entry_connection_st.h"
#include "core/or/extend_info_st.h"
#include "core/or/or_circuit_st.h"
#include "core/or/origin_circuit_st.h"
#include "feature/nodelist/routerinfo_st.h"
#include "core/or/socks_request_st.h"
#include "core/or/sendme.h"

Go to the source code of this file.

Macros
#define	RELAY_PRIVATE
#define	CELL_QUEUE_HIGHWATER_SIZE   256
#define	CELL_QUEUE_LOWWATER_SIZE   64
#define	CELL_PADDING_GAP   4
#define	MAX_RESOLVE_FAILURES   3
#define	EARLY_WARNING_INTERVAL   3600
#define	RELAY_PAYLOAD_LENGTH_FOR_RANDOM_SENDMES    (RELAY_PAYLOAD_SIZE - CELL_PADDING_GAP - 16)
#define	MEMORY_PRESSURE_INTERVAL   (30*60)
#define	RELAY_CIRC_CELL_QUEUE_SIZE_MIN   CIRCWINDOW_START_MAX
#define	RELAY_CIRC_CELL_QUEUE_SIZE_MAX   INT32_MAX
#define	RELAY_CIRC_CELL_QUEUE_SIZE_DEFAULT    (50 * RELAY_CIRC_CELL_QUEUE_SIZE_MIN)

Functions
static edge_connection_t *	relay_lookup_conn (circuit_t *circ, cell_t *cell, cell_direction_t cell_direction, crypt_path_t *layer_hint)
static void	circuit_resume_edge_reading (circuit_t *circ, crypt_path_t *layer_hint)
static int	circuit_resume_edge_reading_helper (edge_connection_t *conn, circuit_t *circ, crypt_path_t *layer_hint)
static int	circuit_consider_stop_edge_reading (circuit_t *circ, crypt_path_t *layer_hint)
static int	circuit_queue_streams_are_blocked (circuit_t *circ)
static void	adjust_exit_policy_from_exitpolicy_failure (origin_circuit_t *circ, entry_connection_t *conn, node_t *node, const tor_addr_t *addr)
static void	circuit_update_channel_usage (circuit_t *circ, cell_t *cell)
int	circuit_receive_relay_cell (cell_t *cell, circuit_t *circ, cell_direction_t cell_direction)
int	circuit_package_relay_cell (cell_t *cell, circuit_t *circ, cell_direction_t cell_direction, crypt_path_t *layer_hint, streamid_t on_stream, const char *filename, int lineno)
void	relay_header_pack (uint8_t *dest, const relay_header_t *src)
void	relay_header_unpack (relay_header_t *dest, const uint8_t *src)
static const char *	relay_command_to_string (uint8_t command)
STATIC size_t	get_pad_cell_offset (size_t data_len)
static void	pad_cell_payload (uint8_t *cell_payload, size_t data_len)
int	relay_send_command_from_edge_ (streamid_t stream_id, circuit_t *circ, uint8_t relay_command, const char *payload, size_t payload_len, crypt_path_t *cpath_layer, const char *filename, int lineno)
int	connection_edge_send_command (edge_connection_t *fromconn, uint8_t relay_command, const char *payload, size_t payload_len)
static int	edge_reason_is_retriable (int reason)
static int	connection_ap_process_end_not_open (relay_header_t *rh, cell_t *cell, origin_circuit_t *circ, entry_connection_t *conn, crypt_path_t *layer_hint)
static void	remap_event_helper (entry_connection_t *conn, const tor_addr_t *new_addr)
STATIC int	connected_cell_parse (const relay_header_t *rh, const cell_t *cell, tor_addr_t *addr_out, int *ttl_out)
STATIC void	address_ttl_free_ (address_ttl_t *addr)
STATIC int	resolved_cell_parse (const cell_t *cell, const relay_header_t *rh, smartlist_t *addresses_out, int *errcode_out)
static void	connection_ap_handshake_socks_got_resolved_cell (entry_connection_t *conn, int error_code, smartlist_t *results)
STATIC int	connection_edge_process_resolved_cell (edge_connection_t *conn, const cell_t *cell, const relay_header_t *rh)
static int	connection_edge_process_relay_cell_not_open (relay_header_t *rh, cell_t *cell, circuit_t *circ, edge_connection_t *conn, crypt_path_t *layer_hint)
static int	process_sendme_cell (const relay_header_t *rh, const cell_t *cell, circuit_t *circ, edge_connection_t *conn, crypt_path_t *layer_hint, int domain)
STATIC int	handle_relay_cell_command (cell_t *cell, circuit_t *circ, edge_connection_t *conn, crypt_path_t *layer_hint, relay_header_t *rh, int optimistic_data)
STATIC int	connection_edge_process_relay_cell (cell_t *cell, circuit_t *circ, edge_connection_t *conn, crypt_path_t *layer_hint)
void	circuit_reset_sendme_randomness (circuit_t *circ)
STATIC size_t	connection_edge_get_inbuf_bytes_to_package (size_t n_available, int package_partial, circuit_t *on_circuit)
int	connection_edge_package_raw_inbuf (edge_connection_t *conn, int package_partial, int *max_cells)
static void	packed_cell_free_unchecked (packed_cell_t *cell)
STATIC packed_cell_t *	packed_cell_new (void)
void	packed_cell_free_ (packed_cell_t *cell)
void	dump_cell_pool_usage (int severity)
static packed_cell_t *	packed_cell_copy (const cell_t *cell, int wide_circ_ids)
void	cell_queue_append (cell_queue_t *queue, packed_cell_t *cell)
void	cell_queue_append_packed_copy (circuit_t *circ, cell_queue_t *queue, int exitward, const cell_t *cell, int wide_circ_ids, int use_stats)
void	cell_queue_init (cell_queue_t *queue)
void	cell_queue_clear (cell_queue_t *queue)
STATIC packed_cell_t *	cell_queue_pop (cell_queue_t *queue)
void	destroy_cell_queue_init (destroy_cell_queue_t *queue)
void	destroy_cell_queue_clear (destroy_cell_queue_t *queue)
STATIC destroy_cell_t *	destroy_cell_queue_pop (destroy_cell_queue_t *queue)
void	destroy_cell_queue_append (destroy_cell_queue_t *queue, circid_t circid, uint8_t reason)
static packed_cell_t *	destroy_cell_to_packed_cell (destroy_cell_t *inp, int wide_circ_ids)
size_t	packed_cell_mem_cost (void)
size_t	cell_queues_get_total_allocation (void)
STATIC int	cell_queues_check_size (void)
int	have_been_under_memory_pressure (void)
void	update_circuit_on_cmux_ (circuit_t *circ, cell_direction_t direction, const char *file, int lineno)
void	channel_unlink_all_circuits (channel_t *chan, smartlist_t *circuits_out)
static int	set_streams_blocked_on_circ (circuit_t *circ, channel_t *chan, int block, streamid_t stream_id)
uint8_t	packed_cell_get_command (const packed_cell_t *cell, int wide_circ_ids)
circid_t	packed_cell_get_circid (const packed_cell_t *cell, int wide_circ_ids)
int	channel_flush_from_first_active_circuit (channel_t *chan, int max)
void	relay_consensus_has_changed (const networkstatus_t *ns)
void	append_cell_to_circuit_queue (circuit_t *circ, channel_t *chan, cell_t *cell, cell_direction_t direction, streamid_t fromstream)
int	append_address_to_payload (uint8_t *payload_out, const tor_addr_t *addr)
const uint8_t *	decode_address_from_payload (tor_addr_t *addr_out, const uint8_t *payload, int payload_len)
void	circuit_clear_cell_queue (circuit_t *circ, channel_t *chan)

Variables
uint64_t	stats_n_relay_cells_relayed = 0
uint64_t	stats_n_relay_cells_delivered = 0
uint64_t	stats_n_circ_max_cell_reached = 0
uint64_t	stats_n_data_cells_packaged = 0
uint64_t	stats_n_data_bytes_packaged = 0
uint64_t	stats_n_data_cells_received = 0
uint64_t	stats_n_data_bytes_received = 0
static size_t	total_cells_allocated = 0
static time_t	last_time_under_memory_pressure = 0
uint64_t	oom_stats_n_bytes_removed_dns = 0
uint64_t	oom_stats_n_bytes_removed_cell = 0
uint64_t	oom_stats_n_bytes_removed_geoip = 0
uint64_t	oom_stats_n_bytes_removed_hsdir = 0
static int32_t	max_circuit_cell_queue_size

Detailed Description

Handle relay cell encryption/decryption, plus packaging and receiving from circuits, plus queuing on circuits.

This is a core modules that makes Tor work. It's responsible for dealing with RELAY cells (the ones that travel more than one hop along a circuit), by:

• constructing relays cells,
• encrypting relay cells,
• decrypting relay cells,
• demultiplexing relay cells as they arrive on a connection,
• queueing relay cells for retransmission,
• or handling relay cells that are for us to receive (as an exit or a client).

RELAY cells are generated throughout the code at the client or relay side, using relay_send_command_from_edge() or one of the functions like connection_edge_send_command() that calls it. Of particular interest is connection_edge_package_raw_inbuf(), which takes information that has arrived on an edge connection socket, and packages it as a RELAY_DATA cell – this is how information is actually sent across the Tor network. The cryptography for these functions is handled deep in circuit_package_relay_cell(), which either adds a single layer of encryption (if we're an exit), or multiple layers (if we're the origin of the circuit). After construction and encryption, the RELAY cells are passed to append_cell_to_circuit_queue(), which queues them for transmission and tells the circuitmux (see circuitmux.c) that the circuit is waiting to send something.

Incoming RELAY cells arrive at circuit_receive_relay_cell(), called from command.c. There they are decrypted and, if they are for us, are passed to connection_edge_process_relay_cell(). If they're not for us, they're re-queued for retransmission again with append_cell_to_circuit_queue().

The connection_edge_process_relay_cell() function handles all the different types of relay cells, launching requests or transmitting data as needed.

Definition in file relay.c.

Macro Definition Documentation

CELL_PADDING_GAP

#define CELL_PADDING_GAP   4

When padding a cell with randomness, leave this many zeros after the payload.

Definition at line 542 of file relay.c.

CELL_QUEUE_HIGHWATER_SIZE

#define CELL_QUEUE_HIGHWATER_SIZE   256

Stop reading on edge connections when we have this many cells waiting on the appropriate queue.

Definition at line 120 of file relay.c.

CELL_QUEUE_LOWWATER_SIZE

#define CELL_QUEUE_LOWWATER_SIZE   64

Start reading from edge connections again when we get down to this many cells.

Definition at line 123 of file relay.c.

MAX_RESOLVE_FAILURES

#define MAX_RESOLVE_FAILURES   3

How many times will I retry a stream that fails due to DNS resolve failure or misc error?

Definition at line 788 of file relay.c.

MEMORY_PRESSURE_INTERVAL

#define MEMORY_PRESSURE_INTERVAL   (30*60)

How long after we've been low on memory should we try to conserve it?

Definition at line 2699 of file relay.c.

RELAY_PAYLOAD_LENGTH_FOR_RANDOM_SENDMES

#define RELAY_PAYLOAD_LENGTH_FOR_RANDOM_SENDMES    (RELAY_PAYLOAD_SIZE - CELL_PADDING_GAP - 16)

Any relay data payload containing fewer than this many real bytes is considered to have enough randomness to.

Definition at line 2081 of file relay.c.

Function Documentation

address_ttl_free_()

STATIC void address_ttl_free_

(

address_ttl_t *

addr

)

Drop all storage held by addr.

Definition at line 1107 of file relay.c.

adjust_exit_policy_from_exitpolicy_failure()

static void adjust_exit_policy_from_exitpolicy_failure ( origin_circuit_t *  circ, entry_connection_t *  conn, node_t *  node, const tor_addr_t *  addr  )

static

Called when we have gotten an END_REASON_EXITPOLICY failure on circ for conn, while attempting to connect via node. If the node told us which address it rejected, then addr is that address; otherwise it is AF_UNSPEC.

If we are sure the node should have allowed this address, mark the node as having a reject *:* exit policy. Otherwise, mark the circuit as unusable for this particular address.

Definition at line 1014 of file relay.c.

append_address_to_payload()

int append_address_to_payload	(	uint8_t *	payload_out,
		const tor_addr_t *	addr
	)

Append an encoded value of addr to payload_out, which must have at least 18 bytes of free space. The encoding is, as specified in tor-spec.txt: RESOLVED_TYPE_IPV4 or RESOLVED_TYPE_IPV6 [1 byte] LENGTH [1 byte] ADDRESS [length bytes] Return the number of bytes added, or -1 on error

Definition at line 3203 of file relay.c.

append_cell_to_circuit_queue()

void append_cell_to_circuit_queue	(	circuit_t *	circ,
		channel_t *	chan,
		cell_t *	cell,
		cell_direction_t	direction,
		streamid_t	fromstream
	)

Add cell to the queue of circ writing to chan transmitting in direction.

The given cell is copied onto the circuit queue so the caller must cleanup the memory.

This function is part of the fast path.

Definition at line 3130 of file relay.c.

cell_queue_append()

void cell_queue_append	(	cell_queue_t *	queue,
		packed_cell_t *	cell
	)

Append cell to the end of queue.

Definition at line 2558 of file relay.c.

Referenced by cell_queue_append_packed_copy().

cell_queue_append_packed_copy()

void cell_queue_append_packed_copy	(	circuit_t *	circ,
		cell_queue_t *	queue,
		int	exitward,
		const cell_t *	cell,
		int	wide_circ_ids,
		int	use_stats
	)

Append a newly allocated copy of cell to the end of the exitward (or app-ward) queue of circ. If use_stats is true, record statistics about the cell.

Definition at line 2569 of file relay.c.

cell_queue_clear()

void cell_queue_clear

(

cell_queue_t *

queue

)

Remove and free every cell in queue.

Definition at line 2593 of file relay.c.

Referenced by circuit_clear_cell_queue().

cell_queue_init()

void cell_queue_init

(

cell_queue_t *

queue

)

Initialize queue as an empty cell queue.

Definition at line 2585 of file relay.c.

Referenced by init_circuit_base().

cell_queue_pop()

STATIC packed_cell_t* cell_queue_pop

(

cell_queue_t *

queue

)

Extract and return the cell at the head of queue; return NULL if queue is empty.

Definition at line 2607 of file relay.c.

cell_queues_check_size()

STATIC int cell_queues_check_size

(

void

)

Check whether we've got too much space used for cells. If so, call the OOM handler and return 1. Otherwise, return 0.

Definition at line 2713 of file relay.c.

channel_flush_from_first_active_circuit()

int channel_flush_from_first_active_circuit	(	channel_t *	chan,
		int	max
	)

Pull as many cells as possible (but no more than max) from the queue of the first active circuit on chan, and write them to chan->outbuf. Return the number of cells written. Advance the active circuit pointer to the next active circuit in the ring.

Definition at line 2917 of file relay.c.

channel_unlink_all_circuits()

void channel_unlink_all_circuits	(	channel_t *	chan,
		smartlist_t *	circuits_out
	)

Remove all circuits from the cmux on chan.

If circuits_out is non-NULL, add all detached circuits to circuits_out.

Definition at line 2826 of file relay.c.

Referenced by circuit_unlink_all_from_channel().

circuit_clear_cell_queue()

void circuit_clear_cell_queue	(	circuit_t *	circ,
		channel_t *	chan
	)

Remove all the cells queued on circ for chan.

Definition at line 3257 of file relay.c.

Referenced by circuit_about_to_free_atexit().

circuit_consider_stop_edge_reading()

static int circuit_consider_stop_edge_reading ( circuit_t *  circ, crypt_path_t *  layer_hint  )

static

Check if the package window for circ is empty (at hop layer_hint if it's defined).

If yes, tell edge streams to stop reading and return 1. Else return 0.

Definition at line 2468 of file relay.c.

circuit_package_relay_cell()

int circuit_package_relay_cell	(	cell_t *	cell,
		circuit_t *	circ,
		cell_direction_t	cell_direction,
		crypt_path_t *	layer_hint,
		streamid_t	on_stream,
		const char *	filename,
		int	lineno
	)

Package a relay cell from an edge:

• Encrypt it to the right layer
• Append it to the appropriate cell_queue on circ.

Definition at line 364 of file relay.c.

circuit_queue_streams_are_blocked()

static int circuit_queue_streams_are_blocked ( circuit_t *  circ )

static

Return 1 if we shouldn't restart reading on this circuit, even if we get a SENDME. Else return 0.

Definition at line 3284 of file relay.c.

Referenced by circuit_resume_edge_reading().

circuit_receive_relay_cell()

int circuit_receive_relay_cell	(	cell_t *	cell,
		circuit_t *	circ,
		cell_direction_t	cell_direction
	)

Receive a relay cell:

• Crypt it (encrypt if headed toward the origin or if we are the origin; decrypt if we're headed toward the exit).
• Check if recognized (if exitward).
• If recognized and the digest checks out, then find if there's a stream that the cell is intended for, and deliver it to the right connection_edge.
• If not recognized, then we need to relay it: append it to the appropriate cell_queue on circ.

Return -reason on failure.

Definition at line 226 of file relay.c.

circuit_reset_sendme_randomness()

void circuit_reset_sendme_randomness

(

circuit_t *

circ

)

Called when initializing a circuit, or when we have reached the end of the window in which we need to send some randomness so that incoming sendme cells will be unpredictable. Resets the flags and picks a new window.

Definition at line 2070 of file relay.c.

Referenced by init_circuit_base().

circuit_resume_edge_reading()

static void circuit_resume_edge_reading ( circuit_t *  circ, crypt_path_t *  layer_hint  )

static

The circuit circ has received a circuit-level sendme (on hop layer_hint, if we're the OP). Go through all the attached streams and let them resume reading and packaging, if their stream windows allow it.

Definition at line 2290 of file relay.c.

circuit_resume_edge_reading_helper()

static int circuit_resume_edge_reading_helper ( edge_connection_t *  first_conn, circuit_t *  circ, crypt_path_t *  layer_hint  )

static

A helper function for circuit_resume_edge_reading() above. The arguments are the same, except that conn is the head of a linked list of edge streams that should each be considered.

Definition at line 2311 of file relay.c.

circuit_update_channel_usage()

static void circuit_update_channel_usage ( circuit_t *  circ, cell_t *  cell  )

static

Update channel usage state based on the type of relay cell and circuit properties.

This is needed to determine if a client channel is being used for application traffic, and if a relay channel is being used for multihop circuits and application traffic. The decision to pad in channelpadding.c depends upon this info (as well as consensus parameters) to decide what channels to pad.

Definition at line 148 of file relay.c.

connected_cell_parse()

STATIC int connected_cell_parse	(	const relay_header_t *	rh,
		const cell_t *	cell,
		tor_addr_t *	addr_out,
		int *	ttl_out
	)

Extract the contents of a connected cell in cell, whose relay header has already been parsed into rh. On success, set addr_out to the address we're connected to, and ttl_out to the ttl of that address, in seconds, and return 0. On failure, return -1.

Note that the resulting address can be UNSPEC if the connected cell had no address (as for a stream to an union service or a tunneled directory connection), and that the ttl can be absent (in which case ttl_out is set to -1).

Definition at line 1069 of file relay.c.

connection_ap_handshake_socks_got_resolved_cell()

static void connection_ap_handshake_socks_got_resolved_cell ( entry_connection_t *  conn, int  error_code, smartlist_t *  results  )

static

Helper for connection_edge_process_resolved_cell: given an error code, an entry_connection, and a list of address_ttl_t *, report the best answer to the entry_connection.

Definition at line 1218 of file relay.c.

connection_ap_process_end_not_open()

static int connection_ap_process_end_not_open ( relay_header_t *  rh, cell_t *  cell, origin_circuit_t *  circ, entry_connection_t *  conn, crypt_path_t *  layer_hint  )

static

Called when we receive an END cell on a stream that isn't open yet, from the client side. Arguments are as for connection_edge_process_relay_cell().

Definition at line 808 of file relay.c.

connection_edge_get_inbuf_bytes_to_package()

STATIC size_t connection_edge_get_inbuf_bytes_to_package	(	size_t	n_available,
		int	package_partial,
		circuit_t *	on_circuit
	)

Helper. Return the number of bytes that should be put into a cell from a given edge connection on which n_available bytes are available.

Definition at line 2089 of file relay.c.

connection_edge_package_raw_inbuf()

int connection_edge_package_raw_inbuf	(	edge_connection_t *	conn,
		int	package_partial,
		int *	max_cells
	)

If conn has an entire relay payload of bytes on its inbuf (or package_partial is true), and the appropriate package windows aren't empty, grab a cell and send it down the circuit.

If *max_cells is given, package no more than max_cells. Decrement *max_cells by the number of cells packaged.

Return -1 (and send a RELAY_COMMAND_END cell if necessary) if conn should be marked for close, else return 0.

Definition at line 2153 of file relay.c.

connection_edge_process_relay_cell()

STATIC int connection_edge_process_relay_cell	(	cell_t *	cell,
		circuit_t *	circ,
		edge_connection_t *	conn,
		crypt_path_t *	layer_hint
	)

An incoming relay cell has arrived on circuit circ. If conn is NULL this is a control cell, else cell is destined for conn.

If layer_hint is defined, then we're the origin of the circuit, and it specifies the hop that packaged cell.

Return -reason if you want to warn and tear down the circuit, else 0.

Definition at line 1982 of file relay.c.

connection_edge_process_relay_cell_not_open()

static int connection_edge_process_relay_cell_not_open ( relay_header_t *  rh, cell_t *  cell, circuit_t *  circ, edge_connection_t *  conn, crypt_path_t *  layer_hint  )

static

An incoming relay cell has arrived from circuit circ to stream conn.

The arguments here are the same as in connection_edge_process_relay_cell() below; this function is called from there when conn is defined and not in an open state.

Definition at line 1367 of file relay.c.

connection_edge_process_resolved_cell()

STATIC int connection_edge_process_resolved_cell	(	edge_connection_t *	conn,
		const cell_t *	cell,
		const relay_header_t *	rh
	)

Handle a RELAY_COMMAND_RESOLVED cell that we received on a non-open AP stream.

Definition at line 1292 of file relay.c.

connection_edge_send_command()

int connection_edge_send_command	(	edge_connection_t *	fromconn,
		uint8_t	relay_command,
		const char *	payload,
		size_t	payload_len
	)

Make a relay cell out of relay_command and payload, and send it onto the open circuit circ. fromconn is the stream that's sending the relay cell, or NULL if it's a control cell. cpath_layer is NULL for OR->OP cells, or the destination hop for OP->OR cells.

If you can't send the cell, mark the circuit for close and return -1. Else return 0.

Definition at line 732 of file relay.c.

decode_address_from_payload()

const uint8_t* decode_address_from_payload	(	tor_addr_t *	addr_out,
		const uint8_t *	payload,
		int	payload_len
	)

Given payload_len bytes at payload, starting with an address encoded as by append_address_to_payload(), try to decode the address into *addr_out. Return the next byte in the payload after the address on success, or NULL on failure.

Definition at line 3229 of file relay.c.

destroy_cell_queue_append()

void destroy_cell_queue_append	(	destroy_cell_queue_t *	queue,
		circid_t	circid,
		uint8_t	reason
	)

Append a destroy cell for circid to queue.

Definition at line 2653 of file relay.c.

destroy_cell_queue_clear()

void destroy_cell_queue_clear

(

destroy_cell_queue_t *

queue

)

Remove and free every cell in queue.

Definition at line 2627 of file relay.c.

destroy_cell_queue_init()

void destroy_cell_queue_init

(

destroy_cell_queue_t *

queue

)

Initialize queue as an empty cell queue.

Definition at line 2619 of file relay.c.

destroy_cell_queue_pop()

STATIC destroy_cell_t* destroy_cell_queue_pop

(

destroy_cell_queue_t *

queue

)

Extract and return the cell at the head of queue; return NULL if queue is empty.

Definition at line 2641 of file relay.c.

Referenced by channel_flush_from_first_active_circuit().

destroy_cell_to_packed_cell()

static packed_cell_t* destroy_cell_to_packed_cell ( destroy_cell_t *  inp, int  wide_circ_ids  )

static

Convert a destroy_cell_t to a newly allocated cell_t. Frees its input.

Definition at line 2669 of file relay.c.

Referenced by channel_flush_from_first_active_circuit().

dump_cell_pool_usage()

void dump_cell_pool_usage

(

int

severity

)

Log current statistics for cell pool allocation at log level severity.

Definition at line 2531 of file relay.c.

Referenced by dumpmemusage().

edge_reason_is_retriable()

static int edge_reason_is_retriable ( int  reason )

static

Return 1 if reason is something that you should retry if you get the end cell before you've connected; else return 0.

Definition at line 793 of file relay.c.

get_pad_cell_offset()

STATIC size_t get_pad_cell_offset

(

size_t

data_len

)

Return the offset where the padding should start. The data_len is the relay payload length expected to be put in the cell. It can not be bigger than RELAY_PAYLOAD_SIZE else this function assert().

Value will always be smaller than CELL_PAYLOAD_SIZE because this offset is for the entire cell length not just the data payload length. Zero is returned if there is no room for padding.

This function always skips the first 4 bytes after the payload because having some unused zero bytes has saved us a lot of times in the past.

Definition at line 556 of file relay.c.

handle_relay_cell_command()

STATIC int handle_relay_cell_command	(	cell_t *	cell,
		circuit_t *	circ,
		edge_connection_t *	conn,
		crypt_path_t *	layer_hint,
		relay_header_t *	rh,
		int	optimistic_data
	)

A helper for connection_edge_process_relay_cell(): Actually handles the cell that we received on the connection.

The arguments are the same as in the parent function connection_edge_process_relay_cell(), plus the relay header rh as unpacked by the parent function, and optimistic_data as set by the parent function.

Definition at line 1592 of file relay.c.

have_been_under_memory_pressure()

int have_been_under_memory_pressure

(

void

)

Return true if we've been under memory pressure in the last MEMORY_PRESSURE_INTERVAL seconds.

Definition at line 2770 of file relay.c.

packed_cell_copy()

static packed_cell_t* packed_cell_copy ( const cell_t *  cell, int  wide_circ_ids  )

inlinestatic

Allocate a new copy of packed cell.

Definition at line 2549 of file relay.c.

Referenced by cell_queue_append_packed_copy().

packed_cell_free_()

void packed_cell_free_

(

packed_cell_t *

cell

)

Return a packed cell used outside by channel_t lower layer

Definition at line 2521 of file relay.c.

packed_cell_free_unchecked()

static void packed_cell_free_unchecked ( packed_cell_t *  cell )

inlinestatic

Release storage held by cell.

Definition at line 2505 of file relay.c.

Referenced by cell_queue_clear(), and packed_cell_free_().

packed_cell_get_circid()

circid_t packed_cell_get_circid	(	const packed_cell_t *	cell,
		int	wide_circ_ids
	)

Extract the circuit ID from a packed cell.

Definition at line 2903 of file relay.c.

packed_cell_get_command()

uint8_t packed_cell_get_command	(	const packed_cell_t *	cell,
		int	wide_circ_ids
	)

Extract the command from a packed cell.

Definition at line 2892 of file relay.c.

Referenced by write_packed_cell().

packed_cell_mem_cost()

size_t packed_cell_mem_cost

(

void

)

Return the total number of bytes used for each packed_cell in a queue. Approximate.

Definition at line 2686 of file relay.c.

packed_cell_new()

STATIC packed_cell_t* packed_cell_new

(

void

)

Allocate and return a new packed_cell_t.

Definition at line 2513 of file relay.c.

Referenced by destroy_cell_to_packed_cell(), and packed_cell_copy().

process_sendme_cell()

static int process_sendme_cell ( const relay_header_t *  rh, const cell_t *  cell, circuit_t *  circ, edge_connection_t *  conn, crypt_path_t *  layer_hint, int  domain  )

static

Process a SENDME cell that arrived on circ. If it is a stream level cell, it is destined for the given conn. If it is a circuit level cell, it is destined for the layer_hint. The domain is the logging domain that should be used.

Return 0 if everything went well or a negative value representing a circuit end reason on error for which the caller is responsible for closing it.

Definition at line 1516 of file relay.c.

relay_command_to_string()

static const char* relay_command_to_string ( uint8_t  command )

static

Convert the relay command into a human-readable string.

Definition at line 502 of file relay.c.

relay_header_pack()

void relay_header_pack	(	uint8_t *	dest,
		const relay_header_t *	src
	)

Pack the relay_header_t host-order structure src into network-order in the buffer dest. See tor-spec.txt for details about the wire format.

Definition at line 478 of file relay.c.

Referenced by relay_set_digest().

relay_header_unpack()

void relay_header_unpack	(	relay_header_t *	dest,
		const uint8_t *	src
	)

Unpack the network-order buffer src into a host-order relay_header_t structure dest.

Definition at line 491 of file relay.c.

Referenced by connection_exit_begin_conn(), connection_exit_begin_resolve(), pathbias_check_probe_response(), pathbias_count_valid_cells(), relay_lookup_conn(), and relay_set_digest().

relay_lookup_conn()

static edge_connection_t * relay_lookup_conn ( circuit_t *  circ, cell_t *  cell, cell_direction_t  cell_direction, crypt_path_t *  layer_hint  )

static

If cell's stream_id matches the stream_id of any conn that's attached to circ, return that conn, else return NULL.

Definition at line 425 of file relay.c.

relay_send_command_from_edge_()

int relay_send_command_from_edge_	(	streamid_t	stream_id,
		circuit_t *	circ,
		uint8_t	relay_command,
		const char *	payload,
		size_t	payload_len,
		crypt_path_t *	cpath_layer,
		const char *	filename,
		int	lineno
	)

Make a relay cell out of relay_command and payload, and send it onto the open circuit circ. stream_id is the ID on circ for the stream that's sending the relay cell, or 0 if it's a control cell. cpath_layer is NULL for OR->OP cells, or the destination hop for OP->OR cells.

If you can't send the cell, mark the circuit for close and return -1. Else return 0.

Definition at line 611 of file relay.c.

remap_event_helper()

static void remap_event_helper ( entry_connection_t *  conn, const tor_addr_t *  new_addr  )

static

Helper: change the socks_request->address field on conn to the dotted-quad representation of new_addr, and send an appropriate REMAP event.

Definition at line 1049 of file relay.c.

resolved_cell_parse()

STATIC int resolved_cell_parse	(	const cell_t *	cell,
		const relay_header_t *	rh,
		smartlist_t *	addresses_out,
		int *	errcode_out
	)

Parse a resolved cell in cell, with parsed header in rh. Return -1 on parse error. On success, add one or more newly allocated address_ttl_t to addresses_out; set *errcode_out to one of 0, RESOLVED_TYPE_ERROR, or RESOLVED_TYPE_ERROR_TRANSIENT, and return 0.

Definition at line 1121 of file relay.c.

set_streams_blocked_on_circ()

static int set_streams_blocked_on_circ ( circuit_t *  circ, channel_t *  chan, int  block, streamid_t  stream_id  )

static

Block (if block is true) or unblock (if block is false) every edge connection that is using circ to write to chan, and start or stop reading as appropriate.

If stream_id is nonzero, block only the edge connection whose stream_id matches it.

Returns the number of streams whose status we changed.

Definition at line 2846 of file relay.c.

update_circuit_on_cmux_()

void update_circuit_on_cmux_	(	circuit_t *	circ,
		cell_direction_t	direction,
		const char *	file,
		int	lineno
	)

Update the number of cells available on the circuit's n_chan or p_chan's circuit mux.

Definition at line 2781 of file relay.c.

Variable Documentation

last_time_under_memory_pressure

time_t last_time_under_memory_pressure = 0

static

The time at which we were last low on memory.

Definition at line 2702 of file relay.c.

Referenced by have_been_under_memory_pressure().

max_circuit_cell_queue_size

int32_t max_circuit_cell_queue_size

static

Initial value:

=
  RELAY_CIRC_CELL_QUEUE_SIZE_DEFAULT

Definition at line 3103 of file relay.c.

oom_stats_n_bytes_removed_dns

uint64_t oom_stats_n_bytes_removed_dns = 0

Statistics on how many bytes were removed by the OOM per type.

Definition at line 2705 of file relay.c.

stats_n_circ_max_cell_reached

uint64_t stats_n_circ_max_cell_reached = 0

Stats: how many circuits have we closed due to the cell queue limit being reached (see append_cell_to_circuit_queue())

Definition at line 135 of file relay.c.

stats_n_data_bytes_packaged

uint64_t stats_n_data_bytes_packaged = 0

How many bytes of data have we put in relay_data cells have we built, ever? This would be RELAY_PAYLOAD_SIZE*stats_n_data_cells_packaged if every relay cell we ever sent were completely full of data.

Definition at line 2056 of file relay.c.

stats_n_data_bytes_received

uint64_t stats_n_data_bytes_received = 0

How many bytes of data have we received relay_data cells, ever? This would be RELAY_PAYLOAD_SIZE*stats_n_data_cells_packaged if every relay cell we ever received were completely full of data.

Definition at line 2062 of file relay.c.

stats_n_data_cells_packaged

uint64_t stats_n_data_cells_packaged = 0

How many relay_data cells have we built, ever?

Definition at line 2052 of file relay.c.

stats_n_data_cells_received

uint64_t stats_n_data_cells_received = 0

How many relay_data cells have we received, ever?

Definition at line 2058 of file relay.c.

stats_n_relay_cells_delivered

uint64_t stats_n_relay_cells_delivered = 0

Stats: how many relay cells have been delivered to streams at this hop?

Definition at line 132 of file relay.c.

stats_n_relay_cells_relayed

uint64_t stats_n_relay_cells_relayed = 0

Stats: how many relay cells have originated at this hop, or have been relayed onward (not recognized at this hop)?

Definition at line 128 of file relay.c.

total_cells_allocated

size_t total_cells_allocated = 0

static

The total number of cells we have allocated.

Definition at line 2501 of file relay.c.

Referenced by packed_cell_free_unchecked(), and packed_cell_new().