Commit 42ef3bd9 authored by Nick Mathewson's avatar Nick Mathewson 🌻
Browse files

Add plausile logging support to eventdns; stop putting stuff onto stdout.


svn:r6728
parent 0ec293b1
......@@ -118,6 +118,14 @@ init_cache_map(void)
HT_INIT(&cache_root);
}
#ifdef USE_EVENTDNS
static void
eventdns_log_cb(const char *msg)
{
log_info(LD_EXIT, "[Eventdns] %s", msg);
}
#endif
/** Initialize the DNS subsystem; called by the OR process. */
void
dns_init(void)
......@@ -125,6 +133,7 @@ dns_init(void)
init_cache_map();
dnsworkers_rotate();
#ifdef USE_EVENTDNS
eventdns_set_log_fn(eventdns_log_cb);
eventdns_resolv_conf_parse(DNS_OPTION_NAMESERVERS|DNS_OPTION_MISC,
"/etc/resolv.conf");
#endif
......
......@@ -4,7 +4,6 @@
// Try to keep this re-mergeable by Adam. Don't make it depend on Tor.
// TODO:
// - Check all malloc return values.
// - Better logging support
// - Learn about nameservers on win32.
/* Async DNS Library
......@@ -248,6 +247,8 @@
#include <limits.h>
#include <sys/stat.h>
#include <ctype.h>
#include <stdio.h>
#include <stdarg.h>
#ifndef HOST_NAME_MAX
#define HOST_NAME_MAX 255
......@@ -272,13 +273,6 @@ typedef unsigned int uint;
#define u16 uint16_t
#define u8 uint8_t
#ifndef NDEBUG
#include <stdio.h>
#define log printf
#else
#define log(x,...)
#endif
#include "eventdns.h"
#define MAX_ADDRS 4 // maximum number of addresses from a single packet
......@@ -387,14 +381,13 @@ last_error(int sock)
}
static int
error_is_eagain(int sock)
error_is_eagain(int err)
{
int err = last_error(sock);
return err == EAGAIN || err == WSAEWOULDBLOCK;
}
#else
#define last_error(sock) (errno)
#define error_is_eagain(sock) (errno == EAGAIN)
#define error_is_eagain(err) ((err) == EAGAIN)
#endif
#define ISSPACE(c) isspace((int)(unsigned char)(c))
......@@ -415,6 +408,34 @@ debug_ntoa(u32 address)
}
#endif
static eventdns_debug_log_fn_type eventdns_log_fn = NULL;
void
eventdns_set_log_fn(eventdns_debug_log_fn_type fn)
{
eventdns_log_fn = fn;
}
static void
_eventdns_log(const char *fmt, ...)
{
va_list args;
static char buf[512];
if (!eventdns_log_fn)
return;
va_start(args,fmt);
#ifdef MS_WINDOWS
_vsnprintf(buf, sizeof(buf), fmt, args);
#else
vsnprintf(buf, sizeof(buf), fmt, args);
#endif
buf[sizeof(buf)-1] = '\0';
eventdns_log_fn(buf);
va_end(args);
}
#define log _eventdns_log
// This walks the list of inflight requests to find the
// one with a matching transaction id. Returns NULL on
// failure
......@@ -461,17 +482,17 @@ nameserver_probe_failed(struct nameserver *const ns) {
// called when a nameserver has been deemed to have failed. For example, too
// many packets have timed out etc
static void
nameserver_failed(struct nameserver *const ns) {
nameserver_failed(struct nameserver *const ns, const char *msg) {
struct request *req, *started_at;
// if this nameserver has already been marked as failed
// then don't do anything
if (!ns->state) return;
log("Nameserver %s has failed\n", debug_ntoa(ns->address));
log("Nameserver %s has failed: %s", debug_ntoa(ns->address), msg);
global_good_nameservers--;
assert(global_good_nameservers >= 0);
if (global_good_nameservers == 0) {
log("All nameservers have failed\n");
log("All nameservers have failed");
}
ns->state = 0;
......@@ -505,7 +526,7 @@ nameserver_failed(struct nameserver *const ns) {
static void
nameserver_up(struct nameserver *const ns) {
if (ns->state) return;
log("Nameserver %s is back up\n", debug_ntoa(ns->address));
log("Nameserver %s is back up", debug_ntoa(ns->address));
evtimer_del(&ns->timeout_event);
ns->state = 1;
ns->failed_times = 0;
......@@ -534,7 +555,7 @@ request_finished(struct request *const req, struct request **head) {
}
}
log("Removing timeout for %lx\n", (unsigned long) req);
log("Removing timeout for request %lx", (unsigned long) req);
evtimer_del(&req->timeout_event);
search_request_finished(req);
......@@ -640,7 +661,10 @@ reply_handle(u16 trans_id, u16 flags, u32 ttl, u32 addrcount, u32 *addresses) {
case DNS_ERR_REFUSED:
// we regard these errors as marking a bad nameserver
if (req->reissue_count < global_max_reissues) {
nameserver_failed(req->ns);
char msg[64];
snprintf(msg, sizeof(msg), "Bad response %d",
error);
nameserver_failed(req->ns, msg);
if (!request_reissue(req)) return;
}
break;
......@@ -853,8 +877,9 @@ nameserver_read(struct nameserver *ns) {
for (;;) {
const int r = recv(ns->socket, packet, sizeof(packet), 0);
if (r < 0) {
if (error_is_eagain(ns->socket)) return;
nameserver_failed(ns);
int err = last_error(ns_socket);
if (error_is_eagain(err)) return;
nameserver_failed(ns, strerror(err));
return;
}
reply_parse(packet, r);
......@@ -990,11 +1015,11 @@ static void
eventdns_request_timeout_callback(int fd, short events, void *arg) {
struct request *const req = (struct request *) arg;
log("Request %lx timed out\n", (unsigned long) arg);
log("Request %lx timed out", (unsigned long) arg);
req->ns->timedout++;
if (req->ns->timedout > global_max_nameserver_timeout) {
nameserver_failed(req->ns);
nameserver_failed(req->ns, "request timed out.");
}
evtimer_del(&req->timeout_event);
......@@ -1018,7 +1043,9 @@ static int
eventdns_request_transmit_to(struct request *req, struct nameserver *server) {
const int r = send(server->socket, req->request, req->request_len, 0);
if (r < 0) {
if (error_is_eagain(server->socket)) return 1;
int err = last_error(server->socket);
if (error_is_eagain(err)) return 1;
nameserver_failed(req->ns, strerror(err));
return 2;
} else if (r != (int)req->request_len) {
return 1; // short write
......@@ -1057,12 +1084,11 @@ eventdns_request_transmit(struct request *req) {
return 1;
case 2:
// failed in some other way
nameserver_failed(req->ns);
retcode = 1;
// fall through
default:
// all ok
log("Setting timeout for %lx\n", (unsigned long) req);
log("Setting timeout for request %lx", (unsigned long) req);
evtimer_set(&req->timeout_event, eventdns_request_timeout_callback, req);
evtimer_add(&req->timeout_event, &global_timeout);
req->tx_count++;
......@@ -1086,7 +1112,7 @@ nameserver_send_probe(struct nameserver *const ns) {
// here we need to send a probe to a given nameserver
// in the hope that it is up now.
log("Sending probe to %s\n", debug_ntoa(ns->address));
log("Sending probe to %s", debug_ntoa(ns->address));
req = request_new("www.google.com", DNS_QUERY_NO_SEARCH, nameserver_probe_callback, ns);
// we force this into the inflight queue no matter what
......@@ -1288,7 +1314,7 @@ request_submit(struct request *const req) {
// exported function
int eventdns_resolve(const char *name, int flags, eventdns_callback_type callback, void *ptr) {
log("resolve for %s\n", name);
log("Resolve requested for %s", name);
if (flags & DNS_QUERY_NO_SEARCH) {
struct request *const req = request_new(name, flags, callback, ptr);
if (!req) return 1;
......@@ -1498,7 +1524,7 @@ search_try_next(struct request *const req) {
if (string_num_dots(req->search_origname) < req->search_state->ndots) {
// yep, we need to try it raw
struct request *const newreq = request_new(req->search_origname, req->search_flags, req->user_callback, req->user_pointer);
log("search: trying raw query %s\n", req->search_origname);
log("Search: trying raw query %s", req->search_origname);
if (newreq) {
request_submit(newreq);
return 0;
......@@ -1508,7 +1534,7 @@ search_try_next(struct request *const req) {
}
new_name = search_make_new(req->search_state, req->search_index, req->search_origname);
log("search: now trying %s (%d)\n", new_name, req->search_index);
log("Search: now trying %s (%d)", new_name, req->search_index);
newreq = request_new(new_name, req->search_flags, req->user_callback, req->user_pointer);
free(new_name);
if (!newreq) return 1;
......@@ -1601,20 +1627,20 @@ resolv_conf_parse_line(char *const start, int flags) {
const int ndots = strtoint(&option[6]);
if (ndots == -1) continue;
if (!(flags & DNS_OPTION_SEARCH)) continue;
log("setting ndots to %d\n", ndots);
log("Setting ndots to %d", ndots);
if (!global_search_state) global_search_state = search_state_new();
global_search_state->ndots = ndots;
} else if (!strncmp(option, "timeout:", 8)) {
const int timeout = strtoint(&option[8]);
if (timeout == -1) continue;
if (!(flags & DNS_OPTION_MISC)) continue;
log("setting timeout to %d\n", timeout);
log("Setting timeout to %d", timeout);
global_timeout.tv_sec = timeout;
} else if (!strncmp(option, "attempts:", 9)) {
const int retries = strtoint(&option[9]);
if (retries == -1) continue;
if (!(flags & DNS_OPTION_MISC)) continue;
log("setting retries to %d\n", retries);
log("Setting retries to %d", retries);
global_max_retransmits = retries;
}
}
......@@ -1638,7 +1664,7 @@ eventdns_resolv_conf_parse(int flags, const char *const filename) {
char *start;
int err = 0;
log("parsing resolve file %s\n", filename);
log("Parsing resolve.conf file %s", filename);
fd = open(filename, O_RDONLY);
if (fd < 0) {
......
......@@ -56,6 +56,9 @@ void eventdns_search_clear(void);
void eventdns_search_add(const char *domain);
void eventdns_search_ndots_set(const int ndots);
typedef void (*eventdns_debug_log_fn_type)(const char *msg);
void evendns_set_log_fn(eventdns_debug_log_fn_type fn);
#define DNS_NO_SEARCH 1
#endif // !EVENTDNS_H
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