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/* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2020, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file reachability.c
* \brief Router reachability testing; run by authorities to tell who is
* running.
*/
#include "core/or/or.h"
#include "feature/dirauth/reachability.h"
#include "app/config/config.h"
#include "core/or/channel.h"
#include "core/or/channeltls.h"
#include "core/or/command.h"
#include "feature/dirauth/authmode.h"
#include "feature/dirauth/dirauth_sys.h"
#include "feature/nodelist/describe.h"
#include "feature/nodelist/nodelist.h"
#include "feature/nodelist/routerinfo.h"
#include "feature/nodelist/routerlist.h"
#include "feature/nodelist/torcert.h"
#include "feature/stats/rephist.h"
#include "feature/dirauth/dirauth_options_st.h"
#include "feature/nodelist/node_st.h"
#include "feature/nodelist/routerinfo_st.h"
#include "feature/nodelist/routerlist_st.h"
/** Called when a TLS handshake has completed successfully with a
* router listening at <b>address</b>:<b>or_port</b>, and has yielded
* a certificate with digest <b>digest_rcvd</b>.
*
* Inform the reachability checker that we could get to this relay.
*/
void
dirserv_orconn_tls_done(const tor_addr_t *addr,
uint16_t or_port,
const char *digest_rcvd,
const ed25519_public_key_t *ed_id_rcvd)
{
node_t *node = NULL;
tor_addr_port_t orport;
routerinfo_t *ri = NULL;
time_t now = time(NULL);
tor_assert(addr);
tor_assert(digest_rcvd);
node = node_get_mutable_by_id(digest_rcvd);
if (node == NULL || node->ri == NULL)
return;
ri = node->ri;
if (dirauth_get_options()->AuthDirTestEd25519LinkKeys &&
node_supports_ed25519_link_authentication(node, 1) &&
ri->cache_info.signing_key_cert) {
/* We allow the node to have an ed25519 key if we haven't been told one in
* the routerinfo, but if we *HAVE* been told one in the routerinfo, it
* needs to match. */
const ed25519_public_key_t *expected_id =
&ri->cache_info.signing_key_cert->signing_key;
tor_assert(!ed25519_public_key_is_zero(expected_id));
if (! ed_id_rcvd || ! ed25519_pubkey_eq(ed_id_rcvd, expected_id)) {
log_info(LD_DIRSERV, "Router at %s:%d with RSA ID %s "
"did not present expected Ed25519 ID.",
fmt_addr(addr), or_port, hex_str(digest_rcvd, DIGEST_LEN));
return; /* Don't mark it as reachable. */
}
}
tor_addr_copy(&orport.addr, addr);
orport.port = or_port;
if (router_has_orport(ri, &orport)) {
/* Found the right router. */
if (!authdir_mode_bridge(get_options()) ||
ri->purpose == ROUTER_PURPOSE_BRIDGE) {
char addrstr[TOR_ADDR_BUF_LEN];
/* This is a bridge or we're not a bridge authority --
mark it as reachable. */
log_info(LD_DIRSERV, "Found router %s to be reachable at %s:%d. Yay.",
router_describe(ri),
tor_addr_to_str(addrstr, addr, sizeof(addrstr), 1),
ri->or_port);
if (tor_addr_family(addr) == AF_INET) {
rep_hist_note_router_reachable(digest_rcvd, addr, or_port, now);
node->last_reachable = now;
} else if (tor_addr_family(addr) == AF_INET6) {
/* No rephist for IPv6. */
node->last_reachable6 = now;
}
}
}
}
/** Called when we, as an authority, receive a new router descriptor either as
* an upload or a download. Used to decide whether to relaunch reachability
* testing for the server. */
int
dirserv_should_launch_reachability_test(const routerinfo_t *ri,
const routerinfo_t *ri_old)
{
if (!authdir_mode_handles_descs(get_options(), ri->purpose))
return 0;
if (!ri_old) {
/* New router: Launch an immediate reachability test, so we will have an
* opinion soon in case we're generating a consensus soon */
return 1;
}
if (ri_old->is_hibernating && !ri->is_hibernating) {
/* It just came out of hibernation; launch a reachability test */
return 1;
}
if (! routers_have_same_or_addrs(ri, ri_old)) {
/* Address or port changed; launch a reachability test */
return 1;
}
return 0;
}
/** Helper function for dirserv_test_reachability(). Start a TLS
* connection to <b>router</b>, and annotate it with when we started
* the test. */
void
dirserv_single_reachability_test(time_t now, routerinfo_t *router)
{
const dirauth_options_t *dirauth_options = dirauth_get_options();
channel_t *chan = NULL;
const node_t *node = NULL;
tor_addr_t router_addr;
const ed25519_public_key_t *ed_id_key;
(void) now;
tor_assert(router);
node = node_get_by_id(router->cache_info.identity_digest);
tor_assert(node);
if (dirauth_options->AuthDirTestEd25519LinkKeys &&
node_supports_ed25519_link_authentication(node, 1) &&
router->cache_info.signing_key_cert) {
ed_id_key = &router->cache_info.signing_key_cert->signing_key;
} else {
ed_id_key = NULL;
}
/* IPv4. */
log_debug(LD_OR,"Testing reachability of %s at %s:%u.",
router->nickname, fmt_addr32(router->addr), router->or_port);
tor_addr_from_ipv4h(&router_addr, router->addr);
chan = channel_tls_connect(&router_addr, router->or_port,
router->cache_info.identity_digest,
ed_id_key);
if (chan) command_setup_channel(chan);
/* Possible IPv6. */
if (dirauth_get_options()->AuthDirHasIPv6Connectivity == 1 &&
!tor_addr_is_null(&router->ipv6_addr)) {
char addrstr[TOR_ADDR_BUF_LEN];
log_debug(LD_OR, "Testing reachability of %s at %s:%u.",
router->nickname,
tor_addr_to_str(addrstr, &router->ipv6_addr, sizeof(addrstr), 1),
router->ipv6_orport);
chan = channel_tls_connect(&router->ipv6_addr, router->ipv6_orport,
router->cache_info.identity_digest,
ed_id_key);
if (chan) command_setup_channel(chan);
}
}
/** Auth dir server only: load balance such that we only
* try a few connections per call.
*
* The load balancing is such that if we get called once every ten
* seconds, we will cycle through all the tests in
* REACHABILITY_TEST_CYCLE_PERIOD seconds (a bit over 20 minutes).
*/
void
dirserv_test_reachability(time_t now)
{
/* XXX decide what to do here; see or-talk thread "purging old router
* information, revocation." -NM
* We can't afford to mess with this in 0.1.2.x. The reason is that
* if we stop doing reachability tests on some of routerlist, then
* we'll for-sure think they're down, which may have unexpected
* effects in other parts of the code. It doesn't hurt much to do
* the testing, and directory authorities are easy to upgrade. Let's
* wait til 0.2.0. -RD */
// time_t cutoff = now - ROUTER_MAX_AGE_TO_PUBLISH;
routerlist_t *rl = router_get_routerlist();
static char ctr = 0;
int bridge_auth = authdir_mode_bridge(get_options());
SMARTLIST_FOREACH_BEGIN(rl->routers, routerinfo_t *, router) {
const char *id_digest = router->cache_info.identity_digest;
if (router_is_me(router))
continue;
if (bridge_auth && router->purpose != ROUTER_PURPOSE_BRIDGE)
continue; /* bridge authorities only test reachability on bridges */
// if (router->cache_info.published_on > cutoff)
// continue;
if ((((uint8_t)id_digest[0]) % REACHABILITY_MODULO_PER_TEST) == ctr) {
dirserv_single_reachability_test(now, router);
}
} SMARTLIST_FOREACH_END(router);
ctr = (ctr + 1) % REACHABILITY_MODULO_PER_TEST; /* increment ctr */
}
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