[tor-commits] [tor/master] Make authority_certs_fetch_missing support bridge hints
nickm at torproject.org
nickm at torproject.org
Fri Jul 1 14:02:01 UTC 2016
commit 516c02b178cf1fd5745280f9979ac67314857ecb
Author: teor (Tim Wilson-Brown) <teor2345 at gmail.com>
Date: Fri Jul 1 14:01:25 2016 +1000
Make authority_certs_fetch_missing support bridge hints
This also fixes an issue where bridge clients may have found a
routerstatus for a directory mirror, and connected to it directly.
---
src/or/routerlist.c | 93 +++++++++++++++++++++++++++++++++++++++--------------
1 file changed, 69 insertions(+), 24 deletions(-)
diff --git a/src/or/routerlist.c b/src/or/routerlist.c
index c08d1a3..d2068a2 100644
--- a/src/or/routerlist.c
+++ b/src/or/routerlist.c
@@ -835,30 +835,65 @@ authority_cert_dl_looks_uncertain(const char *id_digest)
}
/* Fetch the authority certificates specified in resource.
- * If rs is not NULL, fetch from rs, otherwise, fetch from a random directory
- * mirror. */
+ * If we are a bridge client, and node is a configured bridge, fetch from node
+ * using dir_hint as the fingerprint. Otherwise, if rs is not NULL, fetch from
+ * rs. Otherwise, fetch from a random directory mirror. */
static void
authority_certs_fetch_resource_impl(const char *resource,
+ const char *dir_hint,
+ const node_t *node,
const routerstatus_t *rs)
{
+ const or_options_t *options = get_options();
+ int get_via_tor = purpose_needs_anonymity(DIR_PURPOSE_FETCH_CERTIFICATE, 0);
+
+ /* Make sure bridge clients never connect to anything but a bridge */
+ if (options->UseBridges) {
+ if (node && !node_is_a_configured_bridge(node)) {
+ /* If we're using bridges, and node is not a bridge, use a 3-hop path. */
+ get_via_tor = 1;
+ } else if (!node) {
+ /* If we're using bridges, and there's no node, use a 3-hop path. */
+ get_via_tor = 1;
+ }
+ }
+
+ const dir_indirection_t indirection = get_via_tor ? DIRIND_ANONYMOUS
+ : DIRIND_ONEHOP;
+
+ /* If we've just downloaded a consensus from a bridge, re-use that
+ * bridge */
+ if (options->UseBridges && node && !get_via_tor) {
+ /* clients always make OR connections to bridges */
+ tor_addr_port_t or_ap;
+ /* we are willing to use a non-preferred address if we need to */
+ fascist_firewall_choose_address_node(node, FIREWALL_OR_CONNECTION, 0,
+ &or_ap);
+ directory_initiate_command(&or_ap.addr, or_ap.port,
+ NULL, 0, /*no dirport*/
+ dir_hint,
+ DIR_PURPOSE_FETCH_CERTIFICATE,
+ 0,
+ indirection,
+ resource, NULL, 0, 0);
+ return;
+ }
+
if (rs) {
/* If we've just downloaded a consensus from a directory, re-use that
* directory */
- int get_via_tor = purpose_needs_anonymity(
- DIR_PURPOSE_FETCH_CERTIFICATE, 0);
- const dir_indirection_t indirection = get_via_tor ? DIRIND_ANONYMOUS
- : DIRIND_ONEHOP;
directory_initiate_command_routerstatus(rs,
DIR_PURPOSE_FETCH_CERTIFICATE,
0, indirection, resource, NULL,
0, 0);
- } else {
- /* Otherwise, we want certs from a random fallback or directory
- * mirror, because they will almost always succeed. */
- directory_get_from_dirserver(DIR_PURPOSE_FETCH_CERTIFICATE, 0,
- resource, PDS_RETRY_IF_NO_SERVERS,
- DL_WANT_ANY_DIRSERVER);
+ return;
}
+
+ /* Otherwise, we want certs from a random fallback or directory
+ * mirror, because they will almost always succeed. */
+ directory_get_from_dirserver(DIR_PURPOSE_FETCH_CERTIFICATE, 0,
+ resource, PDS_RETRY_IF_NO_SERVERS,
+ DL_WANT_ANY_DIRSERVER);
}
/** Try to download any v3 authority certificates that we may be missing. If
@@ -1038,7 +1073,10 @@ authority_certs_fetch_missing(networkstatus_t *status, time_t now,
} SMARTLIST_FOREACH_END(voter);
}
- /* Look up the routerstatus for the dir_hint */
+ /* Bridge clients look up the node for the dir_hint */
+ const node_t *node = NULL;
+ /* All clients, including bridge clients, look up the routerstatus for the
+ * dir_hint */
const routerstatus_t *rs = NULL;
/* If we still need certificates, try the directory that just successfully
@@ -1046,12 +1084,16 @@ authority_certs_fetch_missing(networkstatus_t *status, time_t now,
* As soon as the directory fails to provide additional certificates, we try
* another, randomly selected directory. This avoids continual retries.
* (We only ever have one outstanding request per certificate.)
- *
- * Bridge clients won't find their bridges using this hint, so they will
- * fall back to using directory_get_from_dirserver, which selects a bridge.
*/
if (dir_hint) {
- /* First try the consensus routerstatus, then the fallback
+ if (options->UseBridges) {
+ /* Bridge clients try the nodelist. If the dir_hint is from an authority,
+ * or something else fetched over tor, we won't find the node here, but
+ * we will find the rs. */
+ node = node_get_by_id(dir_hint);
+ }
+
+ /* All clients try the consensus routerstatus, then the fallback
* routerstatus */
rs = router_get_consensus_status_by_id(dir_hint);
if (!rs) {
@@ -1063,9 +1105,10 @@ authority_certs_fetch_missing(networkstatus_t *status, time_t now,
}
}
- if (!rs) {
- log_warn(LD_BUG, "Directory %s delivered a consensus, but a "
- "routerstatus could not be found for it.",
+ if (!node && !rs) {
+ log_warn(LD_BUG, "Directory %s delivered a consensus, but %s"
+ "no routerstatus could be found for it.",
+ options->UseBridges ? "no node and " : "",
hex_str(dir_hint, DIGEST_LEN));
}
}
@@ -1099,8 +1142,9 @@ authority_certs_fetch_missing(networkstatus_t *status, time_t now,
if (smartlist_len(fps) > 1) {
resource = smartlist_join_strings(fps, "", 0, NULL);
- /* rs is the directory that just gave us a consensus or certificates */
- authority_certs_fetch_resource_impl(resource, rs);
+ /* node and rs are directories that just gave us a consensus or
+ * certificates */
+ authority_certs_fetch_resource_impl(resource, dir_hint, node, rs);
tor_free(resource);
}
/* else we didn't add any: they were all pending */
@@ -1143,8 +1187,9 @@ authority_certs_fetch_missing(networkstatus_t *status, time_t now,
if (smartlist_len(fp_pairs) > 1) {
resource = smartlist_join_strings(fp_pairs, "", 0, NULL);
- /* rs is the directory that just gave us a consensus or certificates */
- authority_certs_fetch_resource_impl(resource, rs);
+ /* node and rs are directories that just gave us a consensus or
+ * certificates */
+ authority_certs_fetch_resource_impl(resource, dir_hint, node, rs);
tor_free(resource);
}
/* else they were all pending */
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