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Add some code to bluntly prevent duplicate guards from getting added

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Apparently something in the directory guard code made it possible
for the same node to get added as a guard over and over when there
were no actual running guard nodes.
This commit is contained in:
Nick Mathewson 2013-02-14 11:48:47 -05:00
parent 47cfee781d
commit 91027218e2
2 changed files with 32 additions and 0 deletions
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29
src/or/entrynodes.c
View file

@ -369,6 +369,15 @@ add_an_entry_guard(const node_t *chosen, int reset_status, int prepend,
if (!node)
return NULL;
}
if (node->using_as_guard)
return NULL;
if (entry_guard_get_by_id_digest(node->identity) != NULL) {
log_info(LD_CIRC, "I was about to add a duplicate entry guard.");
/* This can happen if we choose a guard, then the node goes away, then
* comes back. */
((node_t*) node)->using_as_guard = 1;
return NULL;
}
entry = tor_malloc_zero(sizeof(entry_guard_t));
log_info(LD_CIRC, "Chose %s as new entry guard.",
node_describe(node));
@ -384,6 +393,7 @@ add_an_entry_guard(const node_t *chosen, int reset_status, int prepend,
* this guard. For details, see the Jan 2010 or-dev thread. */
entry->chosen_on_date = time(NULL) - crypto_rand_int(3600*24*30);
entry->chosen_by_version = tor_strdup(VERSION);
((node_t*)node)->using_as_guard = 1;
if (prepend)
smartlist_insert(entry_guards, 0, entry);
else
@ -723,6 +733,21 @@ entry_nodes_should_be_added(void)
should_add_entry_nodes = 1;
}
/** Update the using_as_guard fields of all the nodes. We do this after we
* remove entry guards from the list: This is the only function that clears
* the using_as_guard field. */
static void
update_node_guard_status(void)
{
smartlist_t *nodes = nodelist_get_list();
SMARTLIST_FOREACH(nodes, node_t *, node, node->using_as_guard = 0);
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, entry) {
node_t *node = node_get_mutable_by_id(entry->identity);
if (node)
node->using_as_guard = 1;
} SMARTLIST_FOREACH_END(entry);
}
/** Adjust the entry guards list so that it only contains entries from
* EntryNodes, adding new entries from EntryNodes to the list as needed. */
static void
@ -807,6 +832,8 @@ entry_guards_set_from_config(const or_options_t *options)
SMARTLIST_FOREACH(old_entry_guards_not_on_list, entry_guard_t *, e,
entry_guard_free(e));
update_node_guard_status();
smartlist_free(entry_nodes);
smartlist_free(worse_entry_nodes);
smartlist_free(entry_fps);
@ -1231,6 +1258,8 @@ entry_guards_parse_state(or_state_t *state, int set, char **msg)
* few lines, so we don't have to re-dirty it */
if (remove_obsolete_entry_guards(now))
entry_guards_dirty = 1;
update_node_guard_status();
}
digestmap_free(added_by, tor_free_);
return *msg ? -1 : 0;

3
src/or/or.h
View file

@ -2233,6 +2233,9 @@ typedef struct node_t {
/** Local info: we treat this node as if it rejects everything */
unsigned int rejects_all:1;
/** Local info: this node is in our list of guards */
unsigned int using_as_guard:1;
/* Local info: derived. */
/** True if the IPv6 OR port is preferred over the IPv4 OR port. */