[or-cvs] first cut of the new helper stuff. seems to work in the nor...
arma at seul.org
arma at seul.org
Tue Dec 27 07:23:54 UTC 2005
Update of /home2/or/cvsroot/tor/src/or
In directory moria:/home/arma/work/onion/cvs/tor/src/or
Modified Files:
circuitbuild.c
Log Message:
first cut of the new helper stuff. seems to work in the normal
case, but many edge cases still need testing.
Index: circuitbuild.c
===================================================================
RCS file: /home2/or/cvsroot/tor/src/or/circuitbuild.c,v
retrieving revision 1.189
retrieving revision 1.190
diff -u -p -d -r1.189 -r1.190
--- circuitbuild.c 27 Dec 2005 04:52:34 -0000 1.189
+++ circuitbuild.c 27 Dec 2005 07:23:52 -0000 1.190
@@ -48,10 +48,7 @@ static int onion_extend_cpath(uint8_t pu
cpath_build_state_t *state);
static int count_acceptable_routers(smartlist_t *routers);
static int onion_append_hop(crypt_path_t **head_ptr, extend_info_t *choice);
-static void pick_helper_nodes(void);
-static routerinfo_t *choose_random_helper(routerinfo_t *chosen_exit);
-static void clear_helper_nodes(void);
-static void remove_dead_helpers(void);
+static routerinfo_t *choose_random_helper(cpath_build_state_t *state);
static void helper_nodes_changed(void);
/** Iterate over values of circ_id, starting from conn-\>next_circ_id,
@@ -1508,7 +1505,7 @@ choose_good_entry_server(uint8_t purpose
if (state && options->UseHelperNodes &&
purpose != CIRCUIT_PURPOSE_TESTING) {
- return choose_random_helper(build_state_get_exit_router(state));
+ return choose_random_helper(state);
}
if (state && (r = build_state_get_exit_router(state))) {
@@ -1698,6 +1695,31 @@ build_state_get_exit_nickname(cpath_buil
return state->chosen_exit->nickname;
}
+/** Return the router corresponding to <b>h</b>, if <b>h</b> is
+ * working well enough that we are willing to use it as a helper
+ * right now. (Else return NULL.) In particular, it must be
+ * - Listed as either up or never yet contacted;
+ * - Present in the routerlist;
+ * - Listed as 'fast' by the current dirserver concensus; and
+ * - Allowed by our current ReachableAddresses config option.
+ */
+static INLINE routerinfo_t *
+helper_is_live(helper_node_t *h, int need_uptime, int need_capacity)
+{
+ routerinfo_t *r;
+ if (h->down_since && h->made_contact)
+ return NULL;
+ r = router_get_by_digest(h->identity);
+ if (!r)
+ return NULL;
+ if (router_is_unreliable(r, need_uptime, need_capacity))
+ return NULL;
+ if (firewall_is_fascist() &&
+ !fascist_firewall_allows_address(r->addr,r->or_port))
+ return NULL;
+ return r;
+}
+
/** Return the number of helper nodes that we think are usable. */
static int
num_live_helpers(void)
@@ -1706,11 +1728,55 @@ num_live_helpers(void)
if (! helper_nodes)
return 0;
SMARTLIST_FOREACH(helper_nodes, helper_node_t *, helper,
- if (! helper->down_since && ! helper->unlisted_since)
- ++n;);
+ {
+ if (helper_is_live(helper, 0, 1))
+ ++n;
+ });
return n;
}
+/** Return 1 if <b>digest</b> matches the identity of any entry
+ * in the helper_nodes list. Else return 0. */
+static INLINE int
+is_a_helper(char *digest)
+{
+ SMARTLIST_FOREACH(helper_nodes, helper_node_t *, helper,
+ if(!memcmp(digest, helper->identity, DIGEST_LEN))
+ return 1;
+ );
+ return 0;
+}
+
+#define NUM_HELPER_PICK_TRIES 100
+
+/** Add a new (preferably stable and fast) helper to the end of our
+ * helper_nodes list. Return a pointer to the router if we succeed,
+ * or NULL if we can't find any more suitable helpers. If
+ * <b>tries_left</b> is <= 1, that means you should fail. */
+static routerinfo_t *
+add_a_helper(int tries_left)
+{
+ routerinfo_t *entry;
+ helper_node_t *helper;
+ if (--tries_left <= 0) {
+ warn(LD_CIRC, "Tried finding a new helper, but failed. Bad news. XXX.");
+ return NULL;
+ }
+ entry = choose_good_entry_server(CIRCUIT_PURPOSE_C_GENERAL, NULL);
+ if (!entry)
+ return NULL;
+ /* make sure it's not already a helper */
+ if (is_a_helper(entry->cache_info.identity_digest))
+ return add_a_helper(tries_left); /* recurse */
+ helper = tor_malloc_zero(sizeof(helper_node_t));
+ /* XXXX Downgrade this to info before release. NM */
+ notice(LD_CIRC, "Chose '%s' as new helper node.", entry->nickname);
+ strlcpy(helper->nickname, entry->nickname, sizeof(helper->nickname));
+ memcpy(helper->identity, entry->cache_info.identity_digest, DIGEST_LEN);
+ smartlist_add(helper_nodes, helper);
+ return entry;
+}
+
/** If the use of helper nodes is configured, choose more helper nodes
* until we have enough in the list. */
static void
@@ -1719,43 +1785,22 @@ pick_helper_nodes(void)
or_options_t *options = get_options();
int changed = 0;
- if (! options->UseHelperNodes)
- return;
-
if (!helper_nodes)
helper_nodes = smartlist_create();
- while (smartlist_len(helper_nodes) < options->NumHelperNodes) {
- routerinfo_t *entry =
- choose_good_entry_server(CIRCUIT_PURPOSE_C_GENERAL, NULL);
- /* XXXX deal with duplicate entries. NM */
- helper_node_t *helper = tor_malloc_zero(sizeof(helper_node_t));
- /* XXXX Downgrade this to info before release. NM */
- notice(LD_CIRC, "Chose '%s' as helper node.", entry->nickname);
- strlcpy(helper->nickname, entry->nickname, sizeof(helper->nickname));
- memcpy(helper->identity, entry->cache_info.identity_digest, DIGEST_LEN);
- smartlist_add(helper_nodes, helper);
+ while (num_live_helpers() < options->NumHelperNodes) {
+ if (!add_a_helper(NUM_HELPER_PICK_TRIES))
+ break;
changed = 1;
}
if (changed)
helper_nodes_changed();
}
-/** Remove all elements from the list of helper nodes. */
-static void
-clear_helper_nodes(void)
-{
- SMARTLIST_FOREACH(helper_nodes, helper_node_t *, h, tor_free(h));
- smartlist_clear(helper_nodes);
- helper_nodes_changed();
-}
-
/** Release all storage held by the list of helper nodes. */
void
helper_nodes_free_all(void)
{
- /* Don't call clear_helper_nodes(); that will flush our state change to
- * disk. */
if (helper_nodes) {
SMARTLIST_FOREACH(helper_nodes, helper_node_t *, h, tor_free(h));
smartlist_free(helper_nodes);
@@ -1763,16 +1808,19 @@ helper_nodes_free_all(void)
}
}
+/* XXX These are 12 hours for now, but I'd like to make them 30 days */
+
/** How long (in seconds) do we allow a helper node to be nonfunctional
* before we give up on it? */
-#define HELPER_ALLOW_DOWNTIME 48*60*60
+#define HELPER_ALLOW_DOWNTIME (1*12*60*60)
/** How long (in seconds) do we allow a helper node to be unlisted in the
* directory before we give up on it? */
-#define HELPER_ALLOW_UNLISTED 48*60*60
+#define HELPER_ALLOW_UNLISTED (1*12*60*60)
/** Remove all helper nodes that have been down or unlisted for so
- * long that we don't think they'll come up again. */
-static void
+ * long that we don't think they'll come up again. Return 1 if we
+ * removed any, or 0 if we did nothing. */
+static int
remove_dead_helpers(void)
{
char dbuf[HEX_DIGEST_LEN+1];
@@ -1800,13 +1848,12 @@ remove_dead_helpers(void)
warn(LD_CIRC, "Helper node '%s' (%s) has been %s since %s; removing.",
helper->nickname, dbuf, why, tbuf);
tor_free(helper);
- smartlist_del(helper_nodes, i);
+ smartlist_del_keeporder(helper_nodes, i);
changed = 1;
} else
++i;
}
- if (changed)
- helper_nodes_changed();
+ return changed ? 1 : 0;
}
/** A new directory or router-status has arrived; update the down/listed
@@ -1870,14 +1917,14 @@ helper_nodes_set_status_from_directory(v
}
});
+ if (remove_dead_helpers())
+ changed = 1;
+
if (changed) {
log_fn(severity, LD_CIRC, " (%d/%d helpers are usable)",
num_live_helpers(), smartlist_len(helper_nodes));
helper_nodes_changed();
}
-
- remove_dead_helpers();
- pick_helper_nodes();
}
/** Called when a connection to an OR with the identity digest <b>digest</b>
@@ -1911,13 +1958,20 @@ helper_node_set_status(const char *diges
}
} else {
if (!helper->made_contact) { /* dump him */
+ notice(LD_CIRC,
+ "Connection to never-contacted helper node '%s' failed. "
+ "Removing from the list. %d/%d helpers usable.",
+ helper->nickname,
+ num_live_helpers(), smartlist_len(helper_nodes));
+ tor_free(helper);
+ smartlist_del_keeporder(helper_nodes, helper_sl_idx);
changed = 1;
} else if (!helper->down_since) {
helper->down_since = time(NULL);
warn(LD_CIRC, "Connection to helper node '%s' failed."
" %d/%d helpers usable.",
- helper->nickname, num_live_helpers(),
- smartlist_len(helper_nodes));
+ helper->nickname,
+ num_live_helpers(), smartlist_len(helper_nodes));
changed = 1;
}
}
@@ -1928,32 +1982,55 @@ helper_node_set_status(const char *diges
helper_nodes_changed();
}
-/** Pick a live (up and listed) helper node from the list of helpers, but
- * don't pick <b>exit</b>. If no helpers are available, pick a new list. */
+/** Pick a live (up and listed) helper node from the list of helpers, and
+ * make sure not to pick this circuit's exit. */
static routerinfo_t *
-choose_random_helper(routerinfo_t *chosen_exit)
+choose_random_helper(cpath_build_state_t *state)
{
smartlist_t *live_helpers = smartlist_create();
+ routerinfo_t *chosen_exit = build_state_get_exit_router(state);
routerinfo_t *r;
+ int need_uptime = state->need_uptime;
+ int need_capacity = state->need_capacity;
- if (! helper_nodes)
+ if (! helper_nodes ||
+ smartlist_len(helper_nodes) < get_options()->NumHelperNodes)
pick_helper_nodes();
retry:
+ smartlist_clear(live_helpers);
SMARTLIST_FOREACH(helper_nodes, helper_node_t *, helper,
- if (! helper->down_since && ! helper->unlisted_since) {
- if ((r = router_get_by_digest(helper->identity))) {
- if (r != chosen_exit)
- smartlist_add(live_helpers, r);
- }
- });
+ {
+ r = helper_is_live(helper, need_uptime, need_capacity);
+ if (r && r != chosen_exit) {
+ smartlist_add(live_helpers, r);
+ if (smartlist_len(live_helpers) >= get_options()->NumHelperNodes)
+ break; /* we have enough */
+ }
+ });
- if (! smartlist_len(live_helpers)) {
- /* XXXX Is this right? What if network is down? */
- warn(LD_CIRC, "No functional helper nodes found; picking a new set.");
- clear_helper_nodes();
- pick_helper_nodes();
- goto retry;
+ /* Try to have at least 2 choices available. This way we don't
+ * get stuck with a single live-but-crummy helper and just keep
+ * using him.
+ * (We might get 2 live-but-crummy helpers, but so be it.) */
+ if (smartlist_len(live_helpers) < 2) {
+ if (need_uptime) {
+ need_uptime = 0; /* try without that requirement */
+ goto retry;
+ }
+ /* still no? try adding a new helper then */
+ r = add_a_helper(NUM_HELPER_PICK_TRIES);
+ if (r) {
+ smartlist_add(live_helpers, r);
+ helper_nodes_changed();
+ } else {
+ if (need_capacity) {
+ /* still no? last attempt, try without requiring capacity */
+ need_capacity = 0;
+ goto retry;
+ }
+ /* live_helpers will be empty below. Oh well, we tried. */
+ }
}
r = smartlist_choose(live_helpers);
@@ -1971,7 +2048,7 @@ int
helper_nodes_parse_state(or_state_t *state, int set, const char **err)
{
helper_node_t *node = NULL;
- smartlist_t *helpers = smartlist_create();
+ smartlist_t *new_helpers = smartlist_create();
config_line_t *line;
*err = NULL;
@@ -1980,7 +2057,7 @@ helper_nodes_parse_state(or_state_t *sta
smartlist_t *args = smartlist_create();
node = tor_malloc_zero(sizeof(helper_node_t));
node->made_contact = 1; /* all helpers on disk have been contacted */
- smartlist_add(helpers, node);
+ smartlist_add(new_helpers, node);
smartlist_split_string(args, line->value, " ",
SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
if (smartlist_len(args)<2) {
@@ -2016,16 +2093,14 @@ helper_nodes_parse_state(or_state_t *sta
}
if (*err || !set) {
- SMARTLIST_FOREACH(helpers, helper_node_t *, h, tor_free(h));
- smartlist_free(helpers);
- helpers = NULL;
- }
- if (!*err && set) {
+ SMARTLIST_FOREACH(new_helpers, helper_node_t *, h, tor_free(h));
+ smartlist_free(new_helpers);
+ } else { /* !*err && set */
if (helper_nodes) {
SMARTLIST_FOREACH(helper_nodes, helper_node_t *, h, tor_free(h));
smartlist_free(helper_nodes);
}
- helper_nodes = helpers;
+ helper_nodes = new_helpers;
helper_nodes_dirty = 0;
}
return *err ? -1 : 0;
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