tor/src/or/main.c
Roger Dingledine 267434bdea Implemented congestion control
Servers are allowed to send 100 cells initially, and can't send more until
they receive a 'sendme' cell from that direction, indicating that they
can send 10 more cells. As it currently stands, the exit node quickly
runs out of window, and sends bursts of 10 whenever a sendme cell gets
to him. This is much much much faster (and more flexible) than the old
"give each circuit 1 kB/s and hope nothing overflows" approach.

Also divided out the connection_watch_events into stop_reading,
start_writing, etc. That way we can control them separately.


svn:r54
2002-07-18 06:37:58 +00:00

489 lines
14 KiB
C

/* Copyright 2001,2002 Roger Dingledine, Matej Pfajfar. */
/* See LICENSE for licensing information */
/* $Id$ */
#include "or.h"
/********* START VARIABLES **********/
or_options_t options; /* command-line and config-file options */
int global_role;
static connection_t *connection_array[MAXCONNECTIONS] =
{ NULL };
static struct pollfd poll_array[MAXCONNECTIONS] =
{ [0 ... MAXCONNECTIONS-1] = { -1, 0, 0 } };
static int nfds=0; /* number of connections currently active */
/* private key */
static RSA *prkey = NULL;
/* router array */
static routerinfo_t **router_array = NULL;
static int rarray_len = 0;
/********* END VARIABLES ************/
/****************************************************************************
*
* This section contains accessors and other methods on the connection_array
* and poll_array variables (which are global within this file and unavailable
* outside it).
*
****************************************************************************/
int connection_add(connection_t *conn) {
if(nfds >= MAXCONNECTIONS-2) { /* 2, for some breathing room. should count the fenceposts. */
/* FIXME should use the 'max connections' option */
log(LOG_INFO,"connection_add(): failing because nfds is too high.");
return -1;
}
conn->poll_index = nfds;
connection_set_poll_socket(conn);
connection_array[nfds] = conn;
/* zero these out here, because otherwise we'll inherit values from the previously freed one */
poll_array[nfds].events = 0;
poll_array[nfds].revents = 0;
nfds++;
log(LOG_INFO,"connection_add(): new conn type %d, socket %d, nfds %d.",conn->type, conn->s, nfds);
return 0;
}
void connection_set_poll_socket(connection_t *conn) {
poll_array[conn->poll_index].fd = conn->s;
}
int connection_remove(connection_t *conn) {
int current_index;
assert(conn);
assert(nfds>0);
circuit_about_to_close_connection(conn); /* flush and send destroys for all circuits on this conn */
current_index = conn->poll_index;
if(current_index == nfds-1) { /* this is the end */
// connection_free(conn);
nfds--;
log(LOG_INFO,"connection_remove(): nfds now %d.",nfds);
return 0;
}
/* we replace this one with the one at the end, then free it */
nfds--;
poll_array[current_index].fd = poll_array[nfds].fd;
poll_array[current_index].events = poll_array[nfds].events;
poll_array[current_index].revents = poll_array[nfds].revents;
connection_array[current_index] = connection_array[nfds];
connection_array[current_index]->poll_index = current_index;
log(LOG_INFO,"connection_remove(): nfds now %d.",nfds);
return 0;
}
connection_t *connection_twin_get_by_addr_port(uint32_t addr, uint16_t port) {
/* Find a connection to the router described by addr and port,
* or alternately any router which knows its key.
* This connection *must* be in 'open' state.
* If not, return NULL.
*/
int i;
connection_t *conn;
/* first check if it's there exactly */
conn = connection_exact_get_by_addr_port(addr,port);
if(conn && connection_state_is_open(conn)) {
return conn;
}
/* now check if any of the other open connections are a twin for this one */
/* XXX */
/* guess not */
return NULL;
}
connection_t *connection_exact_get_by_addr_port(uint32_t addr, uint16_t port) {
int i;
connection_t *conn;
for(i=0;i<nfds;i++) {
conn = connection_array[i];
assert(conn);
if(conn->addr == addr && conn->port == port)
return conn;
}
return NULL;
}
connection_t *connection_get_by_type(int type) {
int i;
connection_t *conn;
for(i=0;i<nfds;i++) {
conn = connection_array[i];
if(conn->type == type)
return conn;
}
return NULL;
}
/* the next 4 functions should move to routers.c once we get it
* cleaned up more. The router_array and rarray_len variables should
* move there too.
*/
routerinfo_t *router_get_by_addr_port(uint32_t addr, uint16_t port) {
int i;
routerinfo_t *router;
assert(router_array);
for(i=0;i<rarray_len;i++) {
router = router_array[i];
if ((router->addr == addr) && (router->or_port == port))
return router;
}
return NULL;
}
routerinfo_t *router_get_first_in_route(unsigned int *route, size_t routelen) {
return router_array[route[routelen-1]];
}
/* a wrapper around new_route. put all these in routers.c perhaps? */
unsigned int *router_new_route(size_t *rlen) {
return new_route(options.CoinWeight, router_array,rarray_len, rlen);
}
/* a wrapper around create_onion */
unsigned char *router_create_onion(unsigned int *route, size_t routelen, size_t *lenp, crypt_path_t **cpathp) {
return create_onion(router_array,rarray_len,route,routelen,lenp,cpathp);
}
connection_t *connect_to_router_as_op(routerinfo_t *router) {
return connection_connect_to_router_as_op(router, prkey, options.ORPort);
}
void connection_watch_events(connection_t *conn, short events) {
assert(conn && conn->poll_index < nfds);
poll_array[conn->poll_index].events = events;
}
void connection_stop_reading(connection_t *conn) {
assert(conn && conn->poll_index < nfds);
log(LOG_DEBUG,"connection_stop_reading() called.");
if(poll_array[conn->poll_index].events & POLLIN)
poll_array[conn->poll_index].events -= POLLIN;
}
void connection_start_reading(connection_t *conn) {
assert(conn && conn->poll_index < nfds);
poll_array[conn->poll_index].events |= POLLIN;
}
void connection_stop_writing(connection_t *conn) {
assert(conn && conn->poll_index < nfds);
if(poll_array[conn->poll_index].events & POLLOUT)
poll_array[conn->poll_index].events -= POLLOUT;
}
void connection_start_writing(connection_t *conn) {
assert(conn && conn->poll_index < nfds);
poll_array[conn->poll_index].events |= POLLOUT;
}
void check_conn_read(int i) {
int retval;
connection_t *conn;
if(poll_array[i].revents & POLLIN) { /* something to read */
conn = connection_array[i];
assert(conn);
// log(LOG_DEBUG,"check_conn_read(): socket %d has something to read.",conn->s);
if (conn->type == CONN_TYPE_OP_LISTENER) {
retval = connection_op_handle_listener_read(conn);
} else if (conn->type == CONN_TYPE_OR_LISTENER) {
retval = connection_or_handle_listener_read(conn);
} else if (conn->type == CONN_TYPE_AP_LISTENER) {
retval = connection_ap_handle_listener_read(conn);
} else {
/* else it's an OP, OR, or exit */
retval = connection_read_to_buf(conn);
if (retval >= 0) { /* all still well */
retval = connection_process_inbuf(conn);
// log(LOG_DEBUG,"check_conn_read(): connection_process_inbuf returned %d.",retval);
if(retval >= 0 && !connection_state_is_open(conn) && conn->receiver_bucket == 0) {
log(LOG_DEBUG,"check_conn_read(): receiver bucket reached 0 before handshake finished. Closing.");
retval = -1;
}
}
}
if(retval < 0) { /* this connection is broken. remove it */
log(LOG_DEBUG,"check_conn_read(): Connection broken, removing.");
connection_remove(conn);
connection_free(conn);
if(i<nfds) { /* we just replaced the one at i with a new one.
process it too. */
check_conn_read(i);
}
}
}
}
void check_conn_write(int i) {
int retval;
connection_t *conn;
if(poll_array[i].revents & POLLOUT) { /* something to write */
conn = connection_array[i];
// log(LOG_DEBUG,"check_conn_write(): socket %d wants to write.",conn->s);
if(conn->type == CONN_TYPE_OP_LISTENER ||
conn->type == CONN_TYPE_OR_LISTENER) {
log(LOG_DEBUG,"check_conn_write(): Got a listener socket. Can't happen!");
retval = -1;
} else {
/* else it's an OP, OR, or exit */
retval = connection_flush_buf(conn); /* conns in CONNECTING state will fall through... */
if(retval == 0) { /* it's done flushing */
retval = connection_finished_flushing(conn); /* ...and get handled here. */
}
}
if(retval < 0) { /* this connection is broken. remove it. */
log(LOG_DEBUG,"check_conn_write(): Connection broken, removing.");
connection_remove(conn);
connection_free(conn);
if(i<nfds) { /* we just replaced the one at i with a new one.
process it too. */
check_conn_write(i);
}
}
}
}
void check_conn_marked(int i) {
connection_t *conn;
conn = connection_array[i];
assert(conn);
if(conn->marked_for_close) {
log(LOG_DEBUG,"check_conn_marked(): Cleaning up connection.");
if(conn->s >= 0) { /* might be an incomplete exit connection */
/* FIXME there's got to be a better way to check for this -- and make other checks? */
connection_flush_buf(conn); /* flush it first */
}
connection_remove(conn);
connection_free(conn);
if(i<nfds) { /* we just replaced the one at i with a new one.
process it too. */
check_conn_marked(i);
}
}
}
int prepare_for_poll(int *timeout) {
int i;
int need_to_refill_buckets = 0;
connection_t *conn = NULL;
connection_t *tmpconn;
struct timeval now, soonest;
static int current_second = 0; /* from previous calls to gettimeofday */
int ms_until_conn;
*timeout = -1; /* set it to never timeout, possibly overridden below */
/* first check if we need to refill buckets */
for(i=0;i<nfds;i++) {
if(connection_receiver_bucket_should_increase(connection_array[i])) {
need_to_refill_buckets = 1;
break;
}
}
if(gettimeofday(&now,NULL) < 0)
return -1;
if(need_to_refill_buckets) {
if(now.tv_sec > current_second) { /* the second has already rolled over! */
// log(LOG_DEBUG,"prepare_for_poll(): The second has rolled over, immediately refilling.");
for(i=0;i<nfds;i++)
connection_increment_receiver_bucket(connection_array[i]);
current_second = now.tv_sec; /* remember which second it is, for next time */
}
*timeout = 1000 - (now.tv_usec / 1000); /* how many milliseconds til the next second? */
// log(LOG_DEBUG,"prepare_for_poll(): %d milliseconds til next second.",*timeout);
}
if(options.LinkPadding) {
/* now check which conn wants to speak soonest */
for(i=0;i<nfds;i++) {
tmpconn = connection_array[i];
if(!connection_speaks_cells(tmpconn))
continue; /* this conn type doesn't send cells */
if(!connection_state_is_open(tmpconn))
continue; /* only conns in state 'open' have a valid send_timeval */
while(tv_cmp(&tmpconn->send_timeval,&now) <= 0) { /* send_timeval has already passed, let it send a cell */
// log(LOG_DEBUG,"prepare_for_poll(): doing backlogged connection_send_cell on socket %d (%d ms old)",tmpconn->s,
// (now.tv_sec - tmpconn->send_timeval.tv_sec)*1000 +
// (now.tv_usec - tmpconn->send_timeval.tv_usec)/1000
// );
connection_send_cell(tmpconn);
}
if(!conn || tv_cmp(&tmpconn->send_timeval, &soonest) < 0) { /* this is the best choice so far */
// log(LOG_DEBUG,"prepare_for_poll(): chose socket %d as best connection so far",tmpconn->s);
conn = tmpconn;
soonest.tv_sec = conn->send_timeval.tv_sec;
soonest.tv_usec = conn->send_timeval.tv_usec;
}
}
if(conn) { /* we might want to set *timeout sooner */
ms_until_conn = (soonest.tv_sec - now.tv_sec)*1000 +
(soonest.tv_usec - now.tv_usec)/1000;
// log(LOG_DEBUG,"prepare_for_poll(): conn %d times out in %d ms.",conn->s, ms_until_conn);
if(*timeout == -1 || ms_until_conn < *timeout) { /* use the new one */
// log(LOG_DEBUG,"prepare_for_poll(): conn %d soonest, in %d ms.",conn->s,ms_until_conn);
*timeout = ms_until_conn;
}
}
}
return 0;
}
int do_main_loop(void) {
int i;
int timeout;
int poll_result;
/* load the routers file */
router_array = getrouters(options.RouterFile,&rarray_len, options.ORPort);
if (!router_array)
{
log(LOG_ERR,"Error loading router list.");
return -1;
}
/* load the private key */
prkey = load_prkey(options.PrivateKeyFile);
if (!prkey)
{
log(LOG_ERR,"Error loading private key.");
return -1;
}
log(LOG_DEBUG,"core : Loaded private key of size %u bytes.",RSA_size(prkey));
/* start-up the necessary connections based on global_role. This is where we
* try to connect to all the other ORs, and start the listeners */
retry_all_connections(options.Role, router_array, rarray_len, prkey,
options.ORPort, options.OPPort, options.APPort);
for(;;) {
if(prepare_for_poll(&timeout) < 0) {
log(LOG_DEBUG,"do_main_loop(): prepare_for_poll failed, exiting.");
return -1;
}
/* now timeout is the value we'll hand to poll. It's either -1, meaning
* don't timeout, else it indicates the soonest event (either the
* one-second rollover for refilling receiver buckets, or the soonest
* conn that needs to send a cell)
*/
/* if the timeout is less than 10, set it to 10 */
if(timeout >= 0 && timeout < 10)
timeout = 10;
/* poll until we have an event, or it's time to do something */
poll_result = poll(poll_array, nfds, timeout);
#if 0 /* let catch() handle things like ^c, and otherwise don't worry about it */
if(poll_result < 0) {
log(LOG_ERR,"do_main_loop(): poll failed.");
if(errno != EINTR) /* let the program survive things like ^z */
return -1;
}
#endif
if(poll_result > 0) { /* we have at least one connection to deal with */
/* do all the reads first, so we can detect closed sockets */
for(i=0;i<nfds;i++)
check_conn_read(i); /* this also blows away broken connections */
/* then do the writes */
for(i=0;i<nfds;i++)
check_conn_write(i);
/* any of the conns need to be closed now? */
for(i=0;i<nfds;i++)
check_conn_marked(i);
}
/* refilling buckets and sending cells happens at the beginning of the
* next iteration of the loop, inside prepare_for_poll()
*/
}
}
void catch () {
errno = 0; /* netcat does this. it looks fun. */
log(LOG_DEBUG,"Catching ^c, exiting cleanly.");
exit(0);
}
int main(int argc, char *argv[]) {
int retval = 0;
signal (SIGINT, catch); /* to catch ^c so we can exit cleanly */
if ( getoptions(argc,argv,&options) ) exit(1);
log(options.loglevel,NULL); /* assign logging severity level from options */
global_role = options.Role; /* assign global_role from options. FIX: remove from global namespace later. */
ERR_load_crypto_strings();
retval = do_main_loop();
ERR_free_strings();
return retval;
}