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Make authority_certs_fetch_missing support bridge hints

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This also fixes an issue where bridge clients may have found a
routerstatus for a directory mirror, and connected to it directly.
This commit is contained in:
teor (Tim Wilson-Brown)
2016-07-01 14:01:25 +10:00
parent f90bfaae8d
commit 516c02b178
1 changed files with 69 additions and 24 deletions
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src/or/routerlist.c
+69 -24
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@@ -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 */