Commit 9aa706e2 authored by Nick Mathewson's avatar Nick Mathewson 🐻
Browse files

Bug 691 fix: do not shutdown Tor servers right away if the network is down.

svn:r17566
parent 355369a2
......@@ -6,6 +6,10 @@ Changes in version 0.2.1.9-alpha - 200?-??-??
- When a directory authority gives us a new guess for our IP address,
log which authority we used. Hopefully this will help us debug
the recent complaints about bad IP address guesses.
- When we can't initialize DNS because the network is down, do not
automatically stop Tor from starting. Instead, we retry failed
dns_inits() every 10 minutes, and change the exit policy to reject *:*
until one succeeds. Fixes bug 691.
o Minor features (controller):
- New CONSENSUS_ARRIVED event to note when a new consensus has
......@@ -23,7 +27,7 @@ Changes in version 0.2.1.9-alpha - 200?-??-??
o Minor bugfixes (hidden services):
- Do not throw away existing introduction points on SIGHUP; do not
stall hidden services because of introduction points thrown away.
Patch by Karsten. Fixes bug 874.
Patch by Karsten. Fixes bug 874ma.
Changes in version 0.2.1.8-alpha - 2008-12-08
......
......@@ -290,7 +290,7 @@ static config_var_t _option_vars[] = {
V(RunTesting, BOOL, "0"),
V(SafeLogging, BOOL, "1"),
V(SafeSocks, BOOL, "0"),
V(ServerDNSAllowBrokenResolvConf, BOOL, "0"),
V(ServerDNSAllowBrokenResolvConf, BOOL, "1"),
V(ServerDNSAllowNonRFC953Hostnames, BOOL,"0"),
V(ServerDNSDetectHijacking, BOOL, "1"),
V(ServerDNSRandomizeCase, BOOL, "1"),
......
......@@ -33,6 +33,8 @@ const char dns_c_id[] =
/** Have we currently configured nameservers with eventdns? */
static int nameservers_configured = 0;
/** Did our most recent attempt to configure nameservers with eventdns fail? */
static int nameserver_config_failed = 0;
/** What was the resolv_conf fname we last used when configuring the
* nameservers? Used to check whether we need to reconfigure. */
static char *resolv_conf_fname = NULL;
......@@ -220,12 +222,20 @@ dns_reset(void)
tor_free(resolv_conf_fname);
resolv_conf_mtime = 0;
} else {
if (configure_nameservers(0) < 0)
if (configure_nameservers(0) < 0) {
return -1;
}
}
return 0;
}
/**DOCDOC*/
int
has_dns_init_failed(void)
{
return nameserver_config_failed;
}
/** Helper: Given a TTL from a DNS response, determine what TTL to give the
* OP that asked us to resolve it. */
uint32_t
......@@ -1109,10 +1119,11 @@ evdns_err_is_transient(int err)
}
/** Configure eventdns nameservers if force is true, or if the configuration
* has changed since the last time we called this function. On Unix, this
* reads from options->ServerDNSResolvConfFile or /etc/resolv.conf; on
* Windows, this reads from options->ServerDNSResolvConfFile or the registry.
* Return 0 on success or -1 on failure. */
* has changed since the last time we called this function, or if we failed on
* our last attempt. On Unix, this reads from /etc/resolv.conf or
* options->ServerDNSResolvConfFile; on Windows, this reads from
* options->ServerDNSResolvConfFile or the registry. Return 0 on success or
* -1 on failure. */
static int
configure_nameservers(int force)
{
......@@ -1132,7 +1143,7 @@ configure_nameservers(int force)
if (stat(conf_fname, &st)) {
log_warn(LD_EXIT, "Unable to stat resolver configuration in '%s': %s",
conf_fname, strerror(errno));
return options->ServerDNSAllowBrokenResolvConf ? 0 : -1;
goto err;
}
if (!force && resolv_conf_fname && !strcmp(conf_fname,resolv_conf_fname)
&& st.st_mtime == resolv_conf_mtime) {
......@@ -1147,11 +1158,11 @@ configure_nameservers(int force)
if ((r = evdns_resolv_conf_parse(DNS_OPTIONS_ALL, conf_fname))) {
log_warn(LD_EXIT, "Unable to parse '%s', or no nameservers in '%s' (%d)",
conf_fname, conf_fname, r);
return options->ServerDNSAllowBrokenResolvConf ? 0 : -1;
goto err;
}
if (evdns_count_nameservers() == 0) {
log_warn(LD_EXIT, "Unable to find any nameservers in '%s'.", conf_fname);
return options->ServerDNSAllowBrokenResolvConf ? 0 : -1;
goto err;
}
tor_free(resolv_conf_fname);
resolv_conf_fname = tor_strdup(conf_fname);
......@@ -1167,13 +1178,12 @@ configure_nameservers(int force)
}
if (evdns_config_windows_nameservers()) {
log_warn(LD_EXIT,"Could not config nameservers.");
return options->ServerDNSAllowBrokenResolvConf ? 0 : -1;
goto err;
}
if (evdns_count_nameservers() == 0) {
log_warn(LD_EXIT, "Unable to find any platform nameservers in "
"your Windows configuration. Perhaps you should list a "
"ServerDNSResolvConfFile file in your torrc?");
return options->ServerDNSAllowBrokenResolvConf ? 0 : -1;
"your Windows configuration.");
goto err;
}
if (nameservers_configured)
evdns_resume();
......@@ -1193,7 +1203,18 @@ configure_nameservers(int force)
dns_servers_relaunch_checks();
nameservers_configured = 1;
if (nameserver_config_failed) {
nameserver_config_failed = 0;
mark_my_descriptor_dirty();
}
return 0;
err:
nameservers_configured = 0;
if (! nameserver_config_failed) {
nameserver_config_failed = 1;
mark_my_descriptor_dirty();
}
return -1;
}
/** For eventdns: Called when we get an answer for a request we launched.
......@@ -1284,8 +1305,9 @@ launch_resolve(edge_connection_t *exitconn)
if (!nameservers_configured) {
log_warn(LD_EXIT, "(Harmless.) Nameservers not configured, but resolve "
"launched. Configuring.");
if (configure_nameservers(1) < 0)
if (configure_nameservers(1) < 0) {
return -1;
}
}
r = parse_inaddr_arpa_address(exitconn->_base.address, &in);
......
......@@ -839,6 +839,7 @@ run_scheduled_events(time_t now)
static time_t time_to_recheck_bandwidth = 0;
static time_t time_to_check_for_expired_networkstatus = 0;
static time_t time_to_dump_geoip_stats = 0;
static time_t time_to_retry_dns_init = 0;
or_options_t *options = get_options();
int i;
int have_dir_info;
......@@ -981,6 +982,14 @@ run_scheduled_events(time_t now)
time_to_clean_caches = now + CLEAN_CACHES_INTERVAL;
}
#define RETRY_DNS_INTERVAL (10*60)
/* If we're a server and initializing dns failed, retry periodically. */
if (time_to_retry_dns_init < now) {
time_to_retry_dns_init = now + RETRY_DNS_INTERVAL;
if (server_mode(options) && has_dns_init_failed())
dns_init();
}
/** 2. Periodically, we consider force-uploading our descriptor
* (if we've passed our internal checks). */
......@@ -1367,8 +1376,13 @@ do_main_loop(void)
/* initialize dns resolve map, spawn workers if needed */
if (dns_init() < 0) {
log_err(LD_GENERAL,"Error initializing dns subsystem; exiting");
return -1;
if (get_options()->ServerDNSAllowBrokenResolvConf)
log_warn(LD_GENERAL, "Couldn't set up any working nameservers. "
"Network not up yet? Will try again soon.");
else {
log_err(LD_GENERAL,"Error initializing dns subsystem; exiting. To "
"retry instead, set the ServerDNSAllowBrokenResolvConf option.");
}
}
handle_signals(1);
......
......@@ -3456,6 +3456,7 @@ format_networkstatus_vote(crypto_pk_env_t *private_key,
/********************************* dns.c ***************************/
int dns_init(void);
int has_dns_init_failed(void);
void dns_free_all(void);
uint32_t dns_clip_ttl(uint32_t ttl);
int dns_reset(void);
......
......@@ -1733,7 +1733,7 @@ router_dump_router_to_string(char *s, size_t maxlen, routerinfo_t *router,
}
/* Write the exit policy to the end of 's'. */
if (dns_seems_to_be_broken() ||
if (dns_seems_to_be_broken() || has_dns_init_failed() ||
!router->exit_policy || !smartlist_len(router->exit_policy)) {
/* DNS is screwed up; don't claim to be an exit. */
strlcat(s+written, "reject *:*\n", maxlen-written);
......
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