Commit a25c5d69 authored by Nick Mathewson's avatar Nick Mathewson 🎨
Browse files

r12654@Kushana: nickm | 2007-03-25 19:03:44 -0400

 Add documentation for cell queue functions; make destroy cells result in cell queues getting cleared before the destroy gets sent.


svn:r9907
parent 83b2208e
......@@ -71,7 +71,12 @@ HT_GENERATE(orconn_circid_map, orconn_circid_circuit_map_t, node,
*/
orconn_circid_circuit_map_t *_last_circid_orconn_ent = NULL;
/** DOCDOC */
/** Implementation helper for circuit_set_{p,n}_circid_orconn: A circuit ID
* and/or or_connection for circ has just changed from <b>old_conn, old_id</b>
* to <b>conn, id</b>. Adjust the conn,circid map as appropriate, removing
* the old entry (if any) and adding a new one. If If <b>active</b> is true,
* remove the circuit from the list of active circuits on old_conn and add it
* to the list of active circuits on conn. */
static void
circuit_set_circid_orconn_helper(circuit_t *circ, uint16_t id,
or_connection_t *conn,
......
......@@ -231,10 +231,12 @@ connection_or_process_inbuf(or_connection_t *conn)
}
}
/**DOCDOC*/
/** When adding cells to an OR connection's outbuf, keep adding until the
* outbuf is at least this long, or we run out of cells. */
#define OR_CONN_HIGHWATER (32*1024)
/**DOCDOC*/
/** Add cells to an OR connection's outbuf whenever the outbuf's data length
* drops below this size. */
#define OR_CONN_LOWWATER (16*1024)
/** Called whenever we have flushed some data on an or_conn: add more data
......@@ -243,8 +245,11 @@ int
connection_or_flushed_some(or_connection_t *conn)
{
size_t datalen = buf_datalen(conn->_base.outbuf);
/* If we're under the low water mark, add cells until we're just over the
* high water mark. */
if (datalen < OR_CONN_LOWWATER) {
int n = (OR_CONN_HIGHWATER - datalen) / CELL_NETWORK_SIZE;
int n = (OR_CONN_HIGHWATER - datalen + CELL_NETWORK_SIZE-1)
/ CELL_NETWORK_SIZE;
while (conn->active_circuits && n > 0) {
int flushed = connection_or_flush_from_first_active_circuit(conn, 1);
n -= flushed;
......@@ -726,8 +731,9 @@ connection_tls_finish_handshake(or_connection_t *conn)
return 0;
}
/** Pack <b>cell</b> into wire-format, and write it onto <b>conn</b>'s
* outbuf.
/** Pack <b>cell</b> into wire-format, and write it onto <b>conn</b>'s outbuf.
* For cells that use or affect a circuit, this should only be called by
* connection_or_flush_from_first_active_circuit()
*/
void
connection_or_write_cell_to_buf(const cell_t *cell, or_connection_t *conn)
......@@ -786,6 +792,7 @@ int
connection_or_send_destroy(uint16_t circ_id, or_connection_t *conn, int reason)
{
cell_t cell;
circuit_t *circ;
tor_assert(conn);
......@@ -794,7 +801,12 @@ connection_or_send_destroy(uint16_t circ_id, or_connection_t *conn, int reason)
cell.command = CELL_DESTROY;
cell.payload[0] = (uint8_t) reason;
log_debug(LD_OR,"Sending destroy (circID %d).", circ_id);
/* XXXX clear the rest of the cell queue on the circuit. {cells} */
/* Clear the cell queue on the circuit, so that our destroy cell will
* be the very next thing written.*/
circ = circuit_get_by_circid_orconn(circ_id, conn);
circuit_clear_cell_queue(circ, conn);
connection_or_write_cell_to_buf(&cell, conn);
return 0;
}
......
......@@ -685,11 +685,12 @@ struct cell_t {
char payload[CELL_PAYLOAD_SIZE]; /**< Cell body. */
};
/** DOCDOC */
/** A queue of cells on a circuit, waiting to be added to the
* or_connection_t's outbuf. */
typedef struct cell_queue_t {
cell_t *head;
cell_t *tail;
int n;
cell_t *head; /**< The first cell, or NULL if the queue is empty */
cell_t *tail; /**< The last cell, or NULL if the queue is empty */
int n; /**< The number of cells in the queue */
} cell_queue_t;
/** Beginning of a RELAY cell payload. */
......@@ -754,14 +755,17 @@ typedef struct connection_t {
* connections. Set once we've set the stream end,
* and check in connection_about_to_close_connection().
*/
unsigned int edge_blocked_on_circ:1; /**< DOCDOC */
/** Edge connections only: true if we've blocked writing until the
* circuit has fewer queued cells. */
unsigned int edge_blocked_on_circ:1;
/** Used for OR conns that shouldn't get any new circs attached to them. */
unsigned int or_is_obsolete:1;
/** For AP connections only. If 1, and we fail to reach the chosen exit,
* stop requiring it. */
unsigned int chosen_exit_optional:1;
int s; /**< Our socket; -1 if this connection is closed. */
int s; /**< Our socket; -1 if this connection is closed, or has no
* sockets. */
int conn_array_index; /**< Index into the global connection array. */
struct event *read_event; /**< Libevent event structure. */
struct event *write_event; /**< Libevent event structure. */
......@@ -816,7 +820,11 @@ typedef struct or_connection_t {
* bandwidthburst. (OPEN ORs only) */
int n_circuits; /**< How many circuits use this connection as p_conn or
* n_conn ? */
struct circuit_t *active_circuits; /**< DOCDOC */
/** Double-linked ring of circuits with queued cells waiting for room to
* free up on this connection's outbuf. Every time we pull cells from a
* circuit, we advance this pointer to the next circuit in the ring. */
struct circuit_t *active_circuits;
struct or_connection_t *next_with_same_id; /**< Next connection with same
* identity digest as this one. */
......@@ -1366,7 +1374,7 @@ typedef struct circuit_t {
uint32_t magic; /**< For memory and type debugging: must equal
* ORIGIN_CIRCUIT_MAGIC or OR_CIRCUIT_MAGIC. */
/** DOCDOC */
/** Queue of cells waiting to be transmitted on n_conn. */
cell_queue_t n_conn_cells;
/** The OR connection that is next in this circuit. */
or_connection_t *n_conn;
......@@ -1379,8 +1387,11 @@ typedef struct circuit_t {
/** The IPv4 address of the OR that is next in this circuit. */
uint32_t n_addr;
/** DOCDOC */
/** True iff we are waiting for n_conn_cells to become less full before
* allowing p_streams to add any more cells. (Origin circuit only.) */
unsigned int streams_blocked_on_n_conn : 1;
/** True iff we are waiting for p_conn_cells to become less full before
* allowing n_streams to add any more cells. (OR circuit only.) */
unsigned int streams_blocked_on_p_conn : 1;
/** How many relay data cells can we package (read from edge streams)
......@@ -1412,9 +1423,13 @@ typedef struct circuit_t {
const char *marked_for_close_file; /**< For debugging: in which file was this
* circuit marked for close? */
struct circuit_t *next_active_on_n_conn; /**< DOCDOC */
struct circuit_t *prev_active_on_n_conn; /**< DOCDOC */
struct circuit_t *next; /**< Next circuit in linked list. */
/** Next circuit in the doubly-linked ring of circuits waiting to add
* cells to n_conn. NULL if we have no cells pending. */
struct circuit_t *next_active_on_n_conn;
/** Previous circuit in the doubly-linked ring of circuits waiting to add
* cells to n_conn. NULL if we have no cells pending. */
struct circuit_t *prev_active_on_n_conn;
struct circuit_t *next; /**< Next circuit in linked list of all circuits. */
} circuit_t;
/** An origin_circuit_t holds data necessary to build and use a circuit.
......@@ -1468,12 +1483,16 @@ typedef struct origin_circuit_t {
typedef struct or_circuit_t {
circuit_t _base;
struct circuit_t *next_active_on_p_conn; /**< DOCDOC */
struct circuit_t *prev_active_on_p_conn; /**< DOCDOC */
/** Next circuit in the doubly-linked ring of circuits waiting to add
* cells to p_conn. NULL if we have no cells pending. */
struct circuit_t *next_active_on_p_conn;
/** Previous circuit in the doubly-linked ring of circuits waiting to add
* cells to p_conn. NULL if we have no cells pending. */
struct circuit_t *prev_active_on_p_conn;
/** The circuit_id used in the previous (backward) hop of this circuit. */
circid_t p_circ_id;
/** DOCDOC */
/** Queue of cells waiting to be transmitted on p_conn. */
cell_queue_t p_conn_cells;
/** The OR connection that is previous in this circuit. */
or_connection_t *p_conn;
......@@ -2648,6 +2667,7 @@ int connection_or_flush_from_first_active_circuit(or_connection_t *conn,
void assert_active_circuits_ok(or_connection_t *orconn);
void make_circuit_inactive_on_conn(circuit_t *circ, or_connection_t *conn);
void make_circuit_active_on_conn(circuit_t *circ, or_connection_t *conn);
void circuit_clear_cell_queue(circuit_t *circ, or_connection_t *orconn);
/********************************* rephist.c ***************************/
......
......@@ -131,15 +131,16 @@ relay_crypt_one_payload(crypto_cipher_env_t *cipher, char *in,
}
/** Receive a relay cell:
* - Crypt it (encrypt APward, decrypt at AP, decrypt exitward).
* - Crypt it (encrypt if headed toward the origin or if we <b>are</b> 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 conn that the cell is intended for, and deliver it to
* - 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.
* - Else connection_or_write_cell_to_buf to the conn on the other
* side of the circuit.DOCDOC
* - If not recognized, then we need to relay it: append it to the appropriate
* cell_queue on <b>circ</b>.
*
* Return -reason on failure.
* Return -<b>reason</b> on failure.
*/
int
circuit_receive_relay_cell(cell_t *cell, circuit_t *circ, int cell_direction)
......@@ -322,7 +323,7 @@ relay_crypt(circuit_t *circ, cell_t *cell, int cell_direction,
/** Package a relay cell from an edge:
* - Encrypt it to the right layer
* - connection_or_write_cell_to_buf to the right conn DOCDOC
* - Append it to the appropriate cell_queue on <b>circ</b>
*/
static int
circuit_package_relay_cell(cell_t *cell, circuit_t *circ,
......@@ -1462,19 +1463,21 @@ circuit_consider_sending_sendme(circuit_t *circ, crypt_path_t *layer_hint)
}
}
/** DOCDOC */
/** Stop reading on edge connections when we have this many cells
* waiting on the appropriate queue. */
#define CELL_QUEUE_HIGHWATER_SIZE 256
/** DOCDOC */
/** Start reading from edge connections again when we get down to this many
* cells. */
#define CELL_QUEUE_LOWWATER_SIZE 64
/** DOCDOC */
/** Release storage held by <b>cell</b> */
static INLINE void
cell_free(cell_t *cell)
{
tor_free(cell);
}
/** DOCDOC */
/** Allocate a new copy of <b>cell</b>. */
static INLINE cell_t *
cell_copy(const cell_t *cell)
{
......@@ -1484,7 +1487,7 @@ cell_copy(const cell_t *cell)
return c;
}
/** DOCDOC */
/** Append <b>cell</b> to the end of <b>queue</b>. */
void
cell_queue_append(cell_queue_t *queue, cell_t *cell)
{
......@@ -1499,14 +1502,14 @@ cell_queue_append(cell_queue_t *queue, cell_t *cell)
++queue->n;
}
/** DOCDOC */
/** Append a newly allocated copy of <b>cell</b> to the end of <b>queue</b> */
void
cell_queue_append_copy(cell_queue_t *queue, const cell_t *cell)
{
cell_queue_append(queue, cell_copy(cell));
}
/** DOCDOC */
/** Remove and free every cell in <b>queue</b>. */
void
cell_queue_clear(cell_queue_t *queue)
{
......@@ -1521,7 +1524,8 @@ cell_queue_clear(cell_queue_t *queue)
queue->n = 0;
}
/** DOCDOC */
/** Extract and return the cell at the head of <b>queue</b>; return NULL if
* <b>queue</b> is empty. */
static INLINE cell_t *
cell_queue_pop(cell_queue_t *queue)
{
......@@ -1537,7 +1541,8 @@ cell_queue_pop(cell_queue_t *queue)
return cell;
}
/** DOCDOC */
/** Return a pointer to the "next_active_on_{n,p}_conn" pointer of <b>circ</b>,
* depending on whether <b>conn</b> matches n_conn or p_conn. */
static INLINE circuit_t **
next_circ_on_conn_p(circuit_t *circ, or_connection_t *conn)
{
......@@ -1550,7 +1555,8 @@ next_circ_on_conn_p(circuit_t *circ, or_connection_t *conn)
}
}
/** DOCDOC */
/** Return a pointer to the "prev_active_on_{n,p}_conn" pointer of <b>circ</b>,
* depending on whether <b>conn</b> matches n_conn or p_conn. */
static INLINE circuit_t **
prev_circ_on_conn_p(circuit_t *circ, or_connection_t *conn)
{
......@@ -1563,10 +1569,14 @@ prev_circ_on_conn_p(circuit_t *circ, or_connection_t *conn)
}
}
/** DOCDOC */
/** Add <b>circ</b> to the list of circuits with pending cells on
* <b>conn</b>. */
void
make_circuit_active_on_conn(circuit_t *circ, or_connection_t *conn)
{
tor_assert(! *prev_circ_on_conn_p(circ, conn));
tor_assert(! *next_circ_on_conn_p(circ, conn));
if (! conn->active_circuits) {
conn->active_circuits = circ;
*prev_circ_on_conn_p(circ, conn) = circ;
......@@ -1581,13 +1591,16 @@ make_circuit_active_on_conn(circuit_t *circ, or_connection_t *conn)
}
}
/** DOCDOC */
/** Remove <b>circ</b> to the list of circuits with pending cells on
* <b>conn</b>. */
void
make_circuit_inactive_on_conn(circuit_t *circ, or_connection_t *conn)
{
// XXXX add some assert.
circuit_t *next = *next_circ_on_conn_p(circ, conn);
circuit_t *prev = *next_circ_on_conn_p(circ, conn);
circuit_t *prev = *prev_circ_on_conn_p(circ, conn);
tor_assert(*prev_circ_on_conn_p(next, conn) == circ);
tor_assert(*next_circ_on_conn_p(prev, conn) == circ);
if (next == circ) {
conn->active_circuits = NULL;
} else {
......@@ -1600,7 +1613,8 @@ make_circuit_inactive_on_conn(circuit_t *circ, or_connection_t *conn)
*next_circ_on_conn_p(circ, conn) = NULL;
}
/** DOCDOC */
/** Remove all circuits from the list of circuits with pending cells on
* <b>conn</b>. */
void
connection_or_unlink_all_active_circs(or_connection_t *orconn)
{
......@@ -1617,9 +1631,12 @@ connection_or_unlink_all_active_circs(or_connection_t *orconn)
orconn->active_circuits = NULL;
}
/** DOCDOC */
/** Block (if <b>block</b> is true) or unblock (if <b>block</b> is false)
* every edge connection that is using <b>circ</b> to write to <b>orconn</b>,
* and start or stop reading as appropriate. */
static void
block_streams_on_circ(circuit_t *circ, or_connection_t *orconn, int block)
set_streams_blocked_on_circ(circuit_t *circ, or_connection_t *orconn,
int block)
{
edge_connection_t *edge = NULL;
if (circ->n_conn == orconn) {
......@@ -1647,7 +1664,10 @@ block_streams_on_circ(circuit_t *circ, or_connection_t *orconn, int block)
}
}
/** DOCDOC */
/** Pull as many cells as possible (but no more than <b>max</b>) from the
* queue of the first active circuit on <b>conn</b>, and write then to
* <b>conn</b>-&gt;outbuf. Return the number of cells written. Advance
* the active circuit pointer to the next active circuit in the ring. */
int
connection_or_flush_from_first_active_circuit(or_connection_t *conn, int max)
{
......@@ -1674,9 +1694,12 @@ connection_or_flush_from_first_active_circuit(or_connection_t *conn, int max)
}
conn->active_circuits = *next_circ_on_conn_p(circ, conn);
/* Is the cell queue low enough to unblock all the streams that are waiting
* to write to this circuit? */
if (streams_blocked && queue->n <= CELL_QUEUE_LOWWATER_SIZE)
block_streams_on_circ(circ, conn, 0); /* unblock streams */
set_streams_blocked_on_circ(circ, conn, 0); /* unblock streams */
/* Did we just ran out of cells on this queue? */
if (queue->n == 0) {
log_info(LD_GENERAL, "Made a circuit inactive.");
make_circuit_inactive_on_conn(circ, conn);
......@@ -1684,7 +1707,8 @@ connection_or_flush_from_first_active_circuit(or_connection_t *conn, int max)
return n_flushed;
}
/** DOCDOC */
/** Add <b>cell</b> to the queue of <b>circ</b> writing to <b>orconn</b>
* transmitting in <b>direction</b>. */
void
append_cell_to_circuit_queue(circuit_t *circ, or_connection_t *orconn,
cell_t *cell, int direction)
......@@ -1702,8 +1726,10 @@ append_cell_to_circuit_queue(circuit_t *circ, or_connection_t *orconn,
cell_queue_append_copy(queue, cell);
/* If we have too many cells on the circuit, we should stop reading from
* the edge streams for a while. */
if (!streams_blocked && queue->n >= CELL_QUEUE_HIGHWATER_SIZE)
block_streams_on_circ(circ, orconn, 1); /* block streams */
set_streams_blocked_on_circ(circ, orconn, 1); /* block streams */
if (queue->n == 1) {
/* This was the first cell added to the queue. We need to make this
......@@ -1713,7 +1739,6 @@ append_cell_to_circuit_queue(circuit_t *circ, or_connection_t *orconn,
}
if (! buf_datalen(orconn->_base.outbuf)) {
/* XXXX Should this be a "<16K"? {cells} */
/* There is no data at all waiting to be sent on the outbuf. Add a
* cell, so that we can notice when it gets flushed, flushed_some can
* get called, and we can start putting more data onto the buffer then.
......@@ -1723,7 +1748,29 @@ append_cell_to_circuit_queue(circuit_t *circ, or_connection_t *orconn,
}
}
/** DOCDOC */
/** Remove all the cells queued on <b>circ</b> for <b>orconn</b>. */
void
circuit_clear_cell_queue(circuit_t *circ, or_connection_t *orconn)
{
cell_queue_t *queue;
int streams_blocked;
if (circ->n_conn == orconn) {
queue = &circ->n_conn_cells;
streams_blocked = circ->streams_blocked_on_n_conn;
} else {
or_circuit_t *orcirc = TO_OR_CIRCUIT(circ);
queue = &orcirc->p_conn_cells;
streams_blocked = circ->streams_blocked_on_p_conn;
}
if (queue->n)
make_circuit_inactive_on_conn(circ,orconn);
cell_queue_clear(queue);
}
/** Fail with an assert if the active circuits ring on <b>orconn</b> is
* corrupt. */
void
assert_active_circuits_ok(or_connection_t *orconn)
{
......
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