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comment choose_good_exit_server

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svn:r822
This commit is contained in:
Nick Mathewson 2003-11-17 06:02:41 +00:00
parent 851b0933f5
commit ac5fc456ee
1 changed files with 32 additions and 5 deletions
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35
src/or/onion.c
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@ -235,36 +235,52 @@ static routerinfo_t *choose_good_exit_server(directory_t *dir)
get_connection_array(&carray, &n_connections);
/* Count how many connections are waiting for a circuit to be built.
* We use this for log messages now, but in the future we may depend on it.
*/
for (i = 0; i < n_connections; ++i) {
if (carray[i]->type == CONN_TYPE_AP && carray[i]->state == AP_CONN_STATE_CIRCUIT_WAIT)
++n_pending_connections;
}
log_fn(LOG_DEBUG, "Choosing exit node; %d connections are pending",
n_pending_connections);
/* Now we count, for each of the routers in the directory: how many
* of the pending connections could _definitely_ exit from that
* router (n_supported[i]) and how many could _possibly_ exit from
* that router (n_maybe_supported[i]). (We can't be sure about
* cases where we don't know the IP address of the pending
* connection.)
*/
n_supported = tor_malloc(sizeof(int)*dir->n_routers);
n_maybe_supported = tor_malloc(sizeof(int)*dir->n_routers);
for (i = 0; i < dir->n_routers; ++i) {
for (i = 0; i < dir->n_routers; ++i) { /* iterate over routers */
n_supported[i] = n_maybe_supported[i] = 0;
for (j = 0; j < n_connections; ++j) {
for (j = 0; j < n_connections; ++j) { /* iterate over connections */
if (carray[j]->type != CONN_TYPE_AP ||
carray[j]->state == AP_CONN_STATE_CIRCUIT_WAIT ||
carray[j]->marked_for_close)
continue;
continue; /* Skip everything by open APs in CIRCUIT_WAIT */
switch (connection_ap_can_use_exit(carray[j], dir->routers[i]))
{
case -1:
break;
case 0:
++n_supported[i];
; /* Fall through: If it is supported, it is also maybe supported. */
case 1:
++n_maybe_supported[i];
}
}
} /* End looping over connections. */
if (n_supported[i] > best_support) {
/* If this router is better than previous ones, remember its index
* and goodness, and start counting how many routers are this good. */
best_support = n_supported[i]; best_support_idx = i; n_best_support=1;
} else if (n_supported[i] == best_support) {
/* If this router is _as good_ as the best one, just increment the
* count of equally good routers.*/
++n_best_support;
}
/* As above, but for 'maybe-supported' connections */
if (n_maybe_supported[i] > best_maybe_support) {
best_maybe_support = n_maybe_supported[i]; best_maybe_support_idx = i;
n_best_maybe_support = 1;
@ -275,8 +291,13 @@ static routerinfo_t *choose_good_exit_server(directory_t *dir)
log_fn(LOG_INFO, "Found %d servers that will definitely support %d/%d pending connections, and %d that might support %d/%d.",
n_best_support, best_support, n_pending_connections,
n_best_maybe_support, best_maybe_support, n_pending_connections);
/* If any routers definitely support any pending connections, choose one
* at random. */
if (best_support) {
i = crypto_pseudo_rand_int(n_best_support);
/* Iterate over the routers, until we find the i-th one such that
* n_supported[j] == best_support
*/
for (j = best_support_idx; j < dir->n_routers; ++j) {
if (n_supported[j] == best_support) {
if (i)
@ -287,7 +308,10 @@ static routerinfo_t *choose_good_exit_server(directory_t *dir)
}
}
}
/* This point should never be reached. */
}
/* If any routers _maybe_ support pending connections, choose one at
* random, as above. */
if (best_maybe_support) {
i = crypto_pseudo_rand_int(n_best_maybe_support);
for (j = best_maybe_support_idx; j < dir->n_routers; ++j) {
@ -300,7 +324,10 @@ static routerinfo_t *choose_good_exit_server(directory_t *dir)
}
}
}
/* This point should never be reached. */
}
/* Either there are no pending connections, or no routers even seem to
* possibly support any of them. Choose a router at random. */
tor_free(n_supported); tor_free(n_maybe_supported);
i = crypto_pseudo_rand_int(dir->n_routers);
log_fn(LOG_DEBUG, "Chose exit server '%s'", dir->routers[i]->nickname);