Module Name: src
Committed By: tls
Date: Sun Aug 10 07:00:38 UTC 2014
Modified Files:
src/usr.sbin/ypbind [tls-earlyentropy]: ypbind.8 ypbind.c
Log Message:
Rebase.
To generate a diff of this commit:
cvs rdiff -u -r1.18 -r1.18.38.1 src/usr.sbin/ypbind/ypbind.8
cvs rdiff -u -r1.90 -r1.90.18.1 src/usr.sbin/ypbind/ypbind.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/usr.sbin/ypbind/ypbind.8
diff -u src/usr.sbin/ypbind/ypbind.8:1.18 src/usr.sbin/ypbind/ypbind.8:1.18.38.1
--- src/usr.sbin/ypbind/ypbind.8:1.18 Wed Apr 30 13:11:03 2008
+++ src/usr.sbin/ypbind/ypbind.8 Sun Aug 10 07:00:38 2014
@@ -1,4 +1,4 @@
-.\" $NetBSD: ypbind.8,v 1.18 2008/04/30 13:11:03 martin Exp $
+.\" $NetBSD: ypbind.8,v 1.18.38.1 2014/08/10 07:00:38 tls Exp $
.\"
.\" Copyright (c) 1996 The NetBSD Foundation, Inc.
.\" All rights reserved.
@@ -27,7 +27,7 @@
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
-.Dd February 26, 2005
+.Dd June 14, 2014
.Dt YPBIND 8
.Os
.Sh NAME
@@ -94,9 +94,9 @@ it is bound.
If the binding is somehow lost, e.g by server reboot,
.Nm
marks the domain as unbound and attempts to re-establish the binding.
-When the binding is once again successful,
+If a binding cannot be re-established within 60 seconds,
.Nm
-marks the domain as bound and resumes its periodic check.
+backs off exponentially to trying only once per hour.
.Pp
The options are as follows:
.Bl -tag -width "-broadcast"
@@ -114,7 +114,7 @@ or
servers.
.It Fl ypset
.Xr ypset 8
-may be used to change the server to which a domain is bound.
+may be used from anywhere to change the server to which a domain is bound.
.It Fl ypsetme
.Xr ypset 8
may be used only from this machine to change the server
@@ -122,11 +122,22 @@ to which a domain is bound.
.El
.Pp
The
-.Fl broadcast
+.Fl broadcast ,
.Fl ypset ,
and
-.Fl ypsetme ,
+.Fl ypsetme
options are inherently insecure and should be avoided.
+.Sh SIGNALS
+.Nm
+responds to the following signals:
+.Bl -tag -width TERM -compact
+.It Dv HUP
+causes
+.Nm
+to immediately retry any unbound domains that are currently in
+exponential backoff.
+Use this to resume immediately after a long network outage is
+resolved.
.Sh FILES
.Pa /var/yp/binding/\*[Lt]domain\*[Gt].version
- binding file for \*[Lt]domain\*[Gt].
@@ -147,7 +158,10 @@ facility.
.Xr yppoll 8 ,
.Xr ypset 8
.Sh AUTHORS
+.An -nosplit
This version of
.Nm
-was originally implemented by Theo de Raadt.
-The ypservers support was implemented by Luke Mewburn.
+was originally implemented by
+.An Theo de Raadt .
+The ypservers support was implemented by
+.An Luke Mewburn .
Index: src/usr.sbin/ypbind/ypbind.c
diff -u src/usr.sbin/ypbind/ypbind.c:1.90 src/usr.sbin/ypbind/ypbind.c:1.90.18.1
--- src/usr.sbin/ypbind/ypbind.c:1.90 Tue Aug 30 17:06:22 2011
+++ src/usr.sbin/ypbind/ypbind.c Sun Aug 10 07:00:38 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: ypbind.c,v 1.90 2011/08/30 17:06:22 plunky Exp $ */
+/* $NetBSD: ypbind.c,v 1.90.18.1 2014/08/10 07:00:38 tls Exp $ */
/*
* Copyright (c) 1992, 1993 Theo de Raadt <dera...@fsa.ca>
@@ -28,7 +28,7 @@
#include <sys/cdefs.h>
#ifndef LINT
-__RCSID("$NetBSD: ypbind.c,v 1.90 2011/08/30 17:06:22 plunky Exp $");
+__RCSID("$NetBSD: ypbind.c,v 1.90.18.1 2014/08/10 07:00:38 tls Exp $");
#endif
#include <sys/types.h>
@@ -50,6 +50,7 @@ __RCSID("$NetBSD: ypbind.c,v 1.90 2011/0
#include <ifaddrs.h>
#include <limits.h>
#include <netdb.h>
+#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
@@ -84,16 +85,26 @@ typedef enum {
YPBIND_DIRECT, YPBIND_BROADCAST,
} ypbind_mode_t;
+enum domainstates {
+ DOM_NEW, /* not yet bound */
+ DOM_ALIVE, /* bound and healthy */
+ DOM_PINGING, /* ping outstanding */
+ DOM_LOST, /* binding timed out, looking for a new one */
+ DOM_DEAD, /* long-term lost, in exponential backoff */
+};
+
struct domain {
struct domain *dom_next;
char dom_name[YPMAXDOMAIN + 1];
struct sockaddr_in dom_server_addr;
long dom_vers;
- time_t dom_checktime;
- time_t dom_asktime;
+ time_t dom_checktime; /* time of next check/contact */
+ time_t dom_asktime; /* time we were last DOMAIN'd */
+ time_t dom_losttime; /* time the binding was lost, or 0 */
+ unsigned dom_backofftime; /* current backoff period, when DEAD */
int dom_lockfd;
- int dom_alive;
+ enum domainstates dom_state;
uint32_t dom_xid;
FILE *dom_serversfile; /* /var/yp/binding/foo.ypservers */
int dom_been_ypset; /* ypset been done on this domain? */
@@ -102,26 +113,36 @@ struct domain {
#define BUFSIZE 1400
-static char *domainname;
-
+/* the list of all domains */
static struct domain *domains;
static int check;
+/* option settings */
static ypbind_mode_t default_ypbindmode;
-
static int allow_local_ypset = 0, allow_any_ypset = 0;
static int insecure;
+/* the sockets we use to interact with servers */
static int rpcsock, pingsock;
+
+/* stuff used for manually interacting with servers */
static struct rmtcallargs rmtca;
static struct rmtcallres rmtcr;
static bool_t rmtcr_outval;
static unsigned long rmtcr_port;
+
+/* The ypbind service transports */
static SVCXPRT *udptransp, *tcptransp;
+/* set if we get SIGHUP */
+static sig_atomic_t hupped;
+
////////////////////////////////////////////////////////////
// utilities
+/*
+ * Combo of open() and flock().
+ */
static int
open_locked(const char *path, int flags, mode_t mode)
{
@@ -138,6 +159,39 @@ open_locked(const char *path, int flags,
return fd;
}
+/*
+ * Exponential backoff for pinging servers for a dead domain.
+ *
+ * We go 10 -> 20 -> 40 -> 60 seconds, then 2 -> 4 -> 8 -> 15 -> 30 ->
+ * 60 minutes, and stay at 60 minutes. This is overengineered.
+ *
+ * With a 60 minute max backoff the response time for when things come
+ * back is not awful, but we only try (and log) about 60 times even if
+ * things are down for a whole long weekend. This is an acceptable log
+ * load, I think.
+ */
+static void
+backoff(unsigned *psecs)
+{
+ unsigned secs;
+
+ secs = *psecs;
+ if (secs < 60) {
+ secs *= 2;
+ if (secs > 60) {
+ secs = 60;
+ }
+ } else if (secs < 60 * 15) {
+ secs *= 2;
+ if (secs > 60 * 15) {
+ secs = 60 * 15;
+ }
+ } else if (secs < 60 * 60) {
+ secs *= 2;
+ }
+ *psecs = secs;
+}
+
////////////////////////////////////////////////////////////
// logging
@@ -150,6 +204,9 @@ static int debug;
static void yp_log(int, const char *, ...) __printflike(2, 3);
+/*
+ * Log some stuff, to syslog or stderr depending on the debug setting.
+ */
static void
yp_log(int pri, const char *fmt, ...)
{
@@ -187,6 +244,34 @@ ypservers_filename(const char *domain)
////////////////////////////////////////////////////////////
// struct domain
+/*
+ * The state transitions of a domain work as follows:
+ *
+ * in state NEW:
+ * nag_servers every 5 seconds
+ * upon answer, state is ALIVE
+ *
+ * in state ALIVE:
+ * every 60 seconds, send ping and switch to state PINGING
+ *
+ * in state PINGING:
+ * upon answer, go to state ALIVE
+ * if no answer in 5 seconds, go to state LOST and do nag_servers
+ *
+ * in state LOST:
+ * do nag_servers every 5 seconds
+ * upon answer, go to state ALIVE
+ * if no answer in 60 seconds, go to state DEAD
+ *
+ * in state DEAD
+ * do nag_servers every backofftime seconds (starts at 10)
+ * upon answer go to state ALIVE
+ * backofftime doubles (approximately) each try, with a cap of 1 hour
+ */
+
+/*
+ * Look up a domain by the XID we assigned it.
+ */
static struct domain *
domain_find(uint32_t xid)
{
@@ -198,6 +283,11 @@ domain_find(uint32_t xid)
return dom;
}
+/*
+ * Pick an XID for a domain.
+ *
+ * XXX: this should just generate a random number.
+ */
static uint32_t
unique_xid(struct domain *dom)
{
@@ -210,6 +300,10 @@ unique_xid(struct domain *dom)
return tmp_xid;
}
+/*
+ * Construct a new domain. Adds it to the global linked list of all
+ * domains.
+ */
static struct domain *
domain_create(const char *name)
{
@@ -230,8 +324,10 @@ domain_create(const char *name)
dom->dom_vers = YPVERS;
dom->dom_checktime = 0;
dom->dom_asktime = 0;
+ dom->dom_losttime = 0;
+ dom->dom_backofftime = 10;
dom->dom_lockfd = -1;
- dom->dom_alive = 0;
+ dom->dom_state = DOM_NEW;
dom->dom_xid = unique_xid(dom);
dom->dom_been_ypset = 0;
dom->dom_serversfile = NULL;
@@ -265,6 +361,10 @@ domain_create(const char *name)
////////////////////////////////////////////////////////////
// locks
+/*
+ * Open a new binding file. Does not write the contents out; the
+ * caller (there's only one) does that.
+ */
static int
makelock(struct domain *dom)
{
@@ -286,6 +386,9 @@ makelock(struct domain *dom)
return fd;
}
+/*
+ * Remove a binding file.
+ */
static void
removelock(struct domain *dom)
{
@@ -297,12 +400,14 @@ removelock(struct domain *dom)
}
/*
- * purge_bindingdir: remove old binding files (i.e. "rm BINDINGDIR\/\*.[0-9]")
+ * purge_bindingdir: remove old binding files (i.e. "rm *.[0-9]" in BINDINGDIR)
+ *
+ * The local YP functions [e.g. yp_master()] will fail without even
+ * talking to ypbind if there is a stale (non-flock'd) binding file
+ * present.
*
- * local YP functions [e.g. yp_master()] will fail without even talking
- * to ypbind if there is a stale (non-flock'd) binding file present.
- * we have to scan the entire BINDINGDIR for binding files, because
- * ypbind may bind more than just the yp_get_default_domain() domain.
+ * We have to remove all binding files in BINDINGDIR, not just the one
+ * for the default domain.
*/
static int
purge_bindingdir(const char *dirpath)
@@ -344,7 +449,39 @@ purge_bindingdir(const char *dirpath)
// sunrpc twaddle
/*
- * LOOPBACK IS MORE IMPORTANT: PUT IN HACK
+ * Check if the info coming in is (at least somewhat) valid.
+ */
+static int
+rpc_is_valid_response(char *name, struct sockaddr_in *addr)
+{
+ if (name == NULL) {
+ return 0;
+ }
+
+ if (_yp_invalid_domain(name)) {
+ return 0;
+ }
+
+ /* don't support insecure servers by default */
+ if (!insecure && ntohs(addr->sin_port) >= IPPORT_RESERVED) {
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * Take note of the fact that we've received a reply from a ypserver.
+ * Or, in the case of being ypset, that we've been ypset, which
+ * functions much the same.
+ *
+ * Note that FORCE is set if and only if IS_YPSET is set.
+ *
+ * This function has also for the past 20+ years carried the annotation
+ *
+ * LOOPBACK IS MORE IMPORTANT: PUT IN HACK
+ *
+ * whose meaning isn't entirely clear.
*/
static void
rpc_received(char *dom_name, struct sockaddr_in *raddrp, int force,
@@ -359,46 +496,152 @@ rpc_received(char *dom_name, struct sock
DPRINTF("returned from %s about %s\n",
inet_ntoa(raddrp->sin_addr), dom_name);
- if (dom_name == NULL)
- return;
-
- if (_yp_invalid_domain(dom_name))
- return;
-
- /* don't support insecure servers by default */
- if (!insecure && ntohs(raddrp->sin_port) >= IPPORT_RESERVED)
+ /* validate some stuff */
+ if (!rpc_is_valid_response(dom_name, raddrp)) {
return;
+ }
+ /* look for the domain */
for (dom = domains; dom != NULL; dom = dom->dom_next)
if (!strcmp(dom->dom_name, dom_name))
break;
+ /* if not found, create it, but only if FORCE; otherwise ignore */
if (dom == NULL) {
if (force == 0)
return;
dom = domain_create(dom_name);
}
+ /* the domain needs to know if it's been explicitly ypset */
if (is_ypset) {
dom->dom_been_ypset = 1;
}
- /* soft update, alive */
- if (dom->dom_alive == 1 && force == 0) {
+ /*
+ * If the domain is alive and we aren't being called by ypset,
+ * we shouldn't be getting a response at all. Log it, as it
+ * might be hostile.
+ */
+ if (dom->dom_state == DOM_ALIVE && force == 0) {
+ if (!memcmp(&dom->dom_server_addr, raddrp,
+ sizeof(dom->dom_server_addr))) {
+ yp_log(LOG_WARNING,
+ "Unexpected reply from server %s for domain %s",
+ inet_ntoa(dom->dom_server_addr.sin_addr),
+ dom->dom_name);
+ } else {
+ yp_log(LOG_WARNING,
+ "Falsified reply from %s for domain %s",
+ inet_ntoa(dom->dom_server_addr.sin_addr),
+ dom->dom_name);
+ }
+ return;
+ }
+
+ /*
+ * If we're expected a ping response, and we've got it
+ * (meaning we aren't being called by ypset), we don't need to
+ * do anything.
+ */
+ if (dom->dom_state == DOM_PINGING && force == 0) {
+ /*
+ * If the reply came from the server we expect, set
+ * dom_state back to ALIVE and ping again in 60
+ * seconds.
+ *
+ * If it came from somewhere else, log it.
+ */
if (!memcmp(&dom->dom_server_addr, raddrp,
sizeof(dom->dom_server_addr))) {
- dom->dom_alive = 1;
+ dom->dom_state = DOM_ALIVE;
/* recheck binding in 60 sec */
dom->dom_checktime = time(NULL) + 60;
+ } else {
+ yp_log(LOG_WARNING,
+ "Falsified reply from %s for domain %s",
+ inet_ntoa(dom->dom_server_addr.sin_addr),
+ dom->dom_name);
}
return;
}
-
+
+#ifdef HEURISTIC
+ /*
+ * If transitioning to the alive state from a non-alive state,
+ * clear dom_asktime. This will help prevent any requests that
+ * are still coming in from triggering unnecessary pings via
+ * the HEURISTIC code.
+ *
+ * XXX: this may not be an adequate measure; we may need to
+ * keep more state so we can disable the HEURISTIC code for
+ * the first few seconds after rebinding.
+ */
+ if (dom->dom_state == DOM_NEW ||
+ dom->dom_state == DOM_LOST ||
+ dom->dom_state == DOM_DEAD) {
+ dom->dom_asktime = 0;
+ }
+#endif
+
+ /*
+ * Take the address we got the message from (or in the case of
+ * ypset, the explicit address we were given) as the server
+ * address for this domain, mark the domain alive, and we'll
+ * check it again in 60 seconds.
+ *
+ * XXX: it looks like if we get a random unsolicited reply
+ * from somewhere, we'll silently switch to that server
+ * address, regardless of merit.
+ *
+ * 1. If we have a foo.ypservers file the address should be
+ * checked against it and rejected if it's not one of the
+ * addresses of one of the listed hostnames. Note that it
+ * might not be the same address we sent to; even fairly smart
+ * UDP daemons don't always handle multihomed hosts correctly
+ * and we can't expect sunrpc code to do anything intelligent
+ * at all.
+ *
+ * 2. If we're in broadcast mode the address should be
+ * checked against the local addresses and netmasks so we
+ * don't accept responses from Mars.
+ *
+ * 2a. If we're in broadcast mode and we've been ypset, we
+ * should not accept anything else until we drop the ypset
+ * state for not responding.
+ *
+ * 3. Either way we should not accept a response from an
+ * arbitrary host unless we don't currently have a binding.
+ * (This is now fixed above.)
+ *
+ * Note that for a random unsolicited reply to work it has to
+ * carry the XID of one of the domains we know about; but
+ * those values are predictable.
+ */
(void)memcpy(&dom->dom_server_addr, raddrp,
sizeof(dom->dom_server_addr));
/* recheck binding in 60 seconds */
dom->dom_checktime = time(NULL) + 60;
- dom->dom_alive = 1;
+ dom->dom_state = DOM_ALIVE;
+
+ /* Clear the dead/backoff state. */
+ dom->dom_losttime = 0;
+ dom->dom_backofftime = 10;
+
+ if (is_ypset == 0) {
+ yp_log(LOG_NOTICE, "Domain %s is alive; server %s",
+ dom->dom_name,
+ inet_ntoa(dom->dom_server_addr.sin_addr));
+ }
+
+ /*
+ * Generate a new binding file. If this fails, forget about it.
+ * (But we keep the binding and we'll report it to anyone who
+ * asks via the ypbind service.) XXX: this will interact badly,
+ * maybe very badly, with the code in HEURISTIC.
+ *
+ * Note that makelock() doesn't log on failure.
+ */
if (dom->dom_lockfd != -1)
(void)close(dom->dom_lockfd);
@@ -406,10 +649,6 @@ rpc_received(char *dom_name, struct sock
if ((fd = makelock(dom)) == -1)
return;
- /*
- * ok, if BINDINGDIR exists, and we can create the binding file,
- * then write to it..
- */
dom->dom_lockfd = fd;
iov[0].iov_base = &(udptransp->xp_port);
@@ -436,6 +675,10 @@ rpc_received(char *dom_name, struct sock
}
}
+/*
+ * The NULL call: do nothing. This is obliged to exist because of
+ * sunrpc silliness.
+ */
static void *
/*ARGSUSED*/
ypbindproc_null_2(SVCXPRT *transp, void *argp)
@@ -447,6 +690,9 @@ ypbindproc_null_2(SVCXPRT *transp, void
return (void *)&res;
}
+/*
+ * The DOMAIN call: look up the ypserver for a specified domain.
+ */
static void *
/*ARGSUSED*/
ypbindproc_domain_2(SVCXPRT *transp, void *argp)
@@ -458,12 +704,23 @@ ypbindproc_domain_2(SVCXPRT *transp, voi
int count;
DPRINTF("ypbindproc_domain_2 %s\n", arg);
+
+ /* Reject invalid domains. */
if (_yp_invalid_domain(arg))
return NULL;
(void)memset(&res, 0, sizeof res);
res.ypbind_status = YPBIND_FAIL_VAL;
+ /*
+ * Look for the domain. XXX: Behave erratically if we have
+ * more than 100 domains. The intent here is to avoid allowing
+ * arbitrary incoming requests to create more than 100
+ * domains; but this logic means that if we legitimately have
+ * more than 100 (e.g. via ypset) we'll only actually bind the
+ * first 100 and the rest will fail. The test on 'count' should
+ * be moved further down.
+ */
for (count = 0, dom = domains;
dom != NULL;
dom = dom->dom_next, count++) {
@@ -473,6 +730,16 @@ ypbindproc_domain_2(SVCXPRT *transp, voi
break;
}
+ /*
+ * If the domain doesn't exist, create it, then fail the call
+ * because we have no information yet.
+ *
+ * Set "check" so that checkwork() will run and look for a
+ * server.
+ *
+ * XXX: like during startup there's a spurious call to
+ * removelock() after domain_create().
+ */
if (dom == NULL) {
dom = domain_create(arg);
removelock(dom);
@@ -481,14 +748,30 @@ ypbindproc_domain_2(SVCXPRT *transp, voi
return NULL;
}
- if (dom->dom_alive == 0) {
- DPRINTF("dead domain %s\n", arg);
+ if (dom->dom_state == DOM_NEW) {
+ DPRINTF("new domain %s\n", arg);
return NULL;
}
#ifdef HEURISTIC
+ /*
+ * Keep track of the last time we were explicitly asked about
+ * this domain. If it happens a lot, force a ping. This works
+ * (or "works") because we only get asked specifically when
+ * things aren't going; otherwise the client code in libc and
+ * elsewhere uses the binding file.
+ *
+ * Note: HEURISTIC is enabled by default.
+ *
+ * dholland 20140609: I think this is part of the mechanism
+ * that causes ypbind to spam. I'm changing this logic so it
+ * only triggers when the state is DOM_ALIVE: if the domain
+ * is new, lost, or dead we shouldn't send more requests than
+ * the ones already scheduled, and if we're already in the
+ * middle of pinging there's no point doing it again.
+ */
(void)time(&now);
- if (now < dom->dom_asktime + 5) {
+ if (dom->dom_state == DOM_ALIVE && now < dom->dom_asktime + 5) {
/*
* Hmm. More than 2 requests in 5 seconds have indicated
* that my binding is possibly incorrect.
@@ -514,6 +797,19 @@ ypbindproc_domain_2(SVCXPRT *transp, voi
return &res;
}
+/*
+ * The SETDOM call: ypset.
+ *
+ * Unless -ypsetme was given on the command line, this is rejected;
+ * even then it's only allowed from localhost unless -ypset was
+ * given on the command line.
+ *
+ * Allowing anyone anywhere to ypset you (and therefore provide your
+ * password file and such) is a horrible thing and it isn't clear to
+ * me why this functionality even exists.
+ *
+ * ypset from localhost has some but limited utility.
+ */
static void *
ypbindproc_setdom_2(SVCXPRT *transp, void *argp)
{
@@ -525,6 +821,10 @@ ypbindproc_setdom_2(SVCXPRT *transp, voi
fromsin = svc_getcaller(transp);
DPRINTF("ypbindproc_setdom_2 from %s\n", inet_ntoa(fromsin->sin_addr));
+ /*
+ * Reject unless enabled.
+ */
+
if (allow_any_ypset) {
/* nothing */
} else if (allow_local_ypset) {
@@ -538,16 +838,27 @@ ypbindproc_setdom_2(SVCXPRT *transp, voi
return NULL;
}
+ /* Make a "security" check. */
if (ntohs(fromsin->sin_port) >= IPPORT_RESERVED) {
DPRINTF("ypset from unprivileged port denied\n");
return &res;
}
+ /* Ignore requests we don't understand. */
if (sd->ypsetdom_vers != YPVERS) {
DPRINTF("ypset with wrong version denied\n");
return &res;
}
+ /*
+ * Fetch the arguments out of the xdr-decoded blob and call
+ * rpc_received(), setting FORCE so that the domain will be
+ * created if we don't already know about it, and also saying
+ * that it's actually a ypset.
+ *
+ * Effectively we're telilng rpc_received() that we got an
+ * RPC response from the server specified by ypset.
+ */
(void)memset(&bindsin, 0, sizeof bindsin);
bindsin.sin_family = AF_INET;
bindsin.sin_len = sizeof(bindsin);
@@ -561,6 +872,13 @@ ypbindproc_setdom_2(SVCXPRT *transp, voi
return &res;
}
+/*
+ * Dispatcher for the ypbind service.
+ *
+ * There are three calls: NULL, which does nothing, DOMAIN, which
+ * gets the binding for a particular domain, and SETDOM, which
+ * does ypset.
+ */
static void
ypbindprog_2(struct svc_req *rqstp, register SVCXPRT *transp)
{
@@ -622,6 +940,12 @@ ypbindprog_2(struct svc_req *rqstp, regi
return;
}
+/*
+ * Set up sunrpc stuff.
+ *
+ * This sets up the ypbind service (both TCP and UDP) and also opens
+ * the sockets we use for talking to ypservers.
+ */
static void
sunrpc_setup(void)
{
@@ -670,6 +994,10 @@ sunrpc_setup(void)
////////////////////////////////////////////////////////////
// operational logic
+/*
+ * Broadcast an RPC packet to hopefully contact some servers for a
+ * domain.
+ */
static int
broadcast(char *buf, int outlen)
{
@@ -720,6 +1048,13 @@ broadcast(char *buf, int outlen)
return (0);
}
+/*
+ * Send an RPC packet to all the configured (in /var/yp/foo.ypservers)
+ * servers for a domain.
+ *
+ * XXX: we should read and parse the file up front and reread it only
+ * if it changes.
+ */
static int
direct(char *buf, int outlen, struct domain *dom)
{
@@ -801,6 +1136,11 @@ direct(char *buf, int outlen, struct dom
return 0;
}
+/*
+ * Send an RPC packet to the server that's been selected with ypset.
+ * (This is only used when in broadcast mode and when ypset is
+ * allowed.)
+ */
static int
direct_set(char *buf, int outlen, struct domain *dom)
{
@@ -857,6 +1197,9 @@ direct_set(char *buf, int outlen, struct
return 0;
}
+/*
+ * Receive and dispatch packets on the general RPC socket.
+ */
static enum clnt_stat
handle_replies(void)
{
@@ -911,6 +1254,9 @@ try_again:
return RPC_SUCCESS;
}
+/*
+ * Receive and dispatch packets on the ping socket.
+ */
static enum clnt_stat
handle_ping(void)
{
@@ -965,6 +1311,14 @@ try_again:
return RPC_SUCCESS;
}
+/*
+ * Contact all known servers for a domain in the hopes that one of
+ * them's awake. Also, if we previously had a binding but it timed
+ * out, try the portmapper on that host in case ypserv moved ports for
+ * some reason.
+ *
+ * As a side effect, wipe out any existing binding file.
+ */
static int
nag_servers(struct domain *dom)
{
@@ -1023,7 +1377,7 @@ nag_servers(struct domain *dom)
removelock(dom);
}
- if (dom->dom_alive == 2) {
+ if (dom->dom_state == DOM_PINGING || dom->dom_state == DOM_LOST) {
/*
* This resolves the following situation:
* ypserver on other subnet was once bound,
@@ -1058,6 +1412,9 @@ nag_servers(struct domain *dom)
return -1;
}
+/*
+ * Send a ping message to a domain's current ypserver.
+ */
static int
ping(struct domain *dom)
{
@@ -1107,7 +1464,6 @@ ping(struct domain *dom)
}
AUTH_DESTROY(rpcua);
- dom->dom_alive = 2;
DPRINTF("ping %x\n", dom->dom_server_addr.sin_addr.s_addr);
if (sendto(pingsock, buf, outlen, 0,
@@ -1119,14 +1475,20 @@ ping(struct domain *dom)
}
/*
- * State transition is done like this:
+ * Scan for timer-based work to do.
+ *
+ * If the domain is currently alive, ping the server we're currently
+ * bound to. Otherwise, try all known servers and/or broadcast for a
+ * server via nag_servers.
+ *
+ * Try again in five seconds.
*
- * STATE EVENT ACTION NEWSTATE TIMEOUT
- * no binding timeout broadcast no binding 5 sec
- * no binding answer -- binding 60 sec
- * binding timeout ping server checking 5 sec
- * checking timeout ping server + broadcast checking 5 sec
- * checking answer -- binding 60 sec
+ * If we get back here and the state is still DOM_PINGING, it means
+ * we didn't receive a ping response within five seconds. Declare the
+ * binding lost. If the binding is already lost, and it's been lost
+ * for 60 seconds, switch to DOM_DEAD and begin exponential backoff.
+ * The exponential backoff starts at 10 seconds and tops out at one
+ * hour; see above.
*/
static void
checkwork(void)
@@ -1138,20 +1500,106 @@ checkwork(void)
(void)time(&t);
for (dom = domains; dom != NULL; dom = dom->dom_next) {
- if (dom->dom_checktime < t) {
- if (dom->dom_alive == 1)
- (void)ping(dom);
- else
- (void)nag_servers(dom);
- (void)time(&t);
+ if (dom->dom_checktime >= t) {
+ continue;
+ }
+ switch (dom->dom_state) {
+ case DOM_NEW:
+ /* XXX should be a timeout for this state */
+ dom->dom_checktime = t + 5;
+ (void)nag_servers(dom);
+ break;
+
+ case DOM_ALIVE:
+ dom->dom_state = DOM_PINGING;
+ dom->dom_checktime = t + 5;
+ (void)ping(dom);
+ break;
+
+ case DOM_PINGING:
+ dom->dom_state = DOM_LOST;
+ dom->dom_losttime = t;
dom->dom_checktime = t + 5;
+ yp_log(LOG_NOTICE, "Domain %s lost its binding to "
+ "server %s", dom->dom_name,
+ inet_ntoa(dom->dom_server_addr.sin_addr));
+ (void)nag_servers(dom);
+ break;
+
+ case DOM_LOST:
+ if (t > dom->dom_losttime + 60) {
+ dom->dom_state = DOM_DEAD;
+ dom->dom_backofftime = 10;
+ yp_log(LOG_NOTICE, "Domain %s dead; "
+ "going to exponential backoff",
+ dom->dom_name);
+ }
+ dom->dom_checktime = t + 5;
+ (void)nag_servers(dom);
+ break;
+
+ case DOM_DEAD:
+ dom->dom_checktime = t + dom->dom_backofftime;
+ backoff(&dom->dom_backofftime);
+ (void)nag_servers(dom);
+ break;
}
+ /* re-fetch the time in case we hung sending packets */
+ (void)time(&t);
+ }
+}
+
+/*
+ * Process a hangup signal.
+ *
+ * Do an extra nag_servers() for any domains that are DEAD. This way
+ * if you know things are back up you can restore service by sending
+ * ypbind a SIGHUP rather than waiting for the timeout period.
+ */
+static void
+dohup(void)
+{
+ struct domain *dom;
+
+ hupped = 0;
+ for (dom = domains; dom != NULL; dom = dom->dom_next) {
+ if (dom->dom_state == DOM_DEAD) {
+ (void)nag_servers(dom);
+ }
+ }
+}
+
+/*
+ * Receive a hangup signal.
+ */
+static void
+hup(int __unused sig)
+{
+ hupped = 1;
+}
+
+/*
+ * Initialize hangup processing.
+ */
+static void
+starthup(void)
+{
+ struct sigaction sa;
+
+ sa.sa_handler = hup;
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = SA_RESTART;
+ if (sigaction(SIGHUP, &sa, NULL) == -1) {
+ err(1, "sigaction");
}
}
////////////////////////////////////////////////////////////
// main
+/*
+ * Usage message.
+ */
__dead static void
usage(void)
{
@@ -1166,23 +1614,25 @@ usage(void)
exit(1);
}
+/*
+ * Main.
+ */
int
main(int argc, char *argv[])
{
struct timeval tv;
fd_set fdsr;
int width, lockfd;
- int evil = 0;
+ int started = 0;
+ char *domainname;
setprogname(argv[0]);
- (void)yp_get_default_domain(&domainname);
- if (domainname[0] == '\0')
- errx(1, "Domainname not set. Aborting.");
- if (_yp_invalid_domain(domainname))
- errx(1, "Invalid domainname: %s", domainname);
- default_ypbindmode = YPBIND_DIRECT;
+ /*
+ * Process arguments.
+ */
+ default_ypbindmode = YPBIND_DIRECT;
while (--argc) {
++argv;
if (!strcmp("-insecure", *argv)) {
@@ -1204,27 +1654,72 @@ main(int argc, char *argv[])
}
}
- /* initialise syslog */
+ /*
+ * Look up the name of the default domain.
+ */
+
+ (void)yp_get_default_domain(&domainname);
+ if (domainname[0] == '\0')
+ errx(1, "Domainname not set. Aborting.");
+ if (_yp_invalid_domain(domainname))
+ errx(1, "Invalid domainname: %s", domainname);
+
+ /*
+ * Start things up.
+ */
+
+ /* Open the system log. */
openlog("ypbind", LOG_PERROR | LOG_PID, LOG_DAEMON);
- /* acquire ypbind.lock */
+ /* Acquire /var/run/ypbind.lock. */
lockfd = open_locked(_PATH_YPBIND_LOCK, O_CREAT|O_RDWR|O_TRUNC, 0644);
if (lockfd == -1)
err(1, "Cannot create %s", _PATH_YPBIND_LOCK);
- /* initialize sunrpc stuff */
+ /* Accept hangups. */
+ starthup();
+
+ /* Initialize sunrpc stuff. */
sunrpc_setup();
- /* blow away old bindings in BINDINGDIR */
+ /* Clean out BINDINGDIR, deleting all existing (now stale) bindings */
if (purge_bindingdir(BINDINGDIR) < 0)
- errx(1, "unable to purge old bindings from %s", BINDINGDIR);
+ errx(1, "Unable to purge old bindings from %s", BINDINGDIR);
+
+ /*
+ * We start with one binding, for the default domain. It starts
+ * out "unsuccessful".
+ *
+ * XXX: domain_create adds the new domain to 'domains' (the
+ * global linked list) and therefore we shouldn't assign
+ * 'domains' again on return.
+ */
- /* build initial domain binding, make it "unsuccessful" */
domains = domain_create(domainname);
+
+ /*
+ * Delete the lock for the default domain again, just in case something
+ * magically caused it to appear since purge_bindingdir() was called.
+ * XXX: this is useless and redundant; remove it.
+ */
removelock(domains);
+ /*
+ * Main loop. Wake up at least once a second and check for
+ * timer-based work to do (checkwork) and also handle incoming
+ * responses from ypservers and any RPCs made to the ypbind
+ * service.
+ *
+ * There are two sockets used for ypserver traffic: one for
+ * pings and one for everything else. These call XDR manually
+ * for encoding and are *not* dispatched via the sunrpc
+ * libraries.
+ *
+ * The ypbind serivce *is* dispatched via the sunrpc libraries.
+ * svc_getreqset() does whatever internal muck and ultimately
+ * ypbind service calls arrive at ypbindprog_2().
+ */
checkwork();
-
for (;;) {
width = svc_maxfd;
if (rpcsock > width)
@@ -1240,24 +1735,55 @@ main(int argc, char *argv[])
switch (select(width, &fdsr, NULL, NULL, &tv)) {
case 0:
+ /* select timed out - check for timer-based work */
+ if (hupped) {
+ dohup();
+ }
checkwork();
break;
case -1:
- yp_log(LOG_WARNING, "select: %s", strerror(errno));
+ if (hupped) {
+ dohup();
+ }
+ if (errno != EINTR) {
+ yp_log(LOG_WARNING, "select: %s",
+ strerror(errno));
+ }
break;
default:
+ if (hupped) {
+ dohup();
+ }
+ /* incoming of our own; read it */
if (FD_ISSET(rpcsock, &fdsr))
(void)handle_replies();
if (FD_ISSET(pingsock, &fdsr))
(void)handle_ping();
+
+ /* read any incoming packets for the ypbind service */
svc_getreqset(&fdsr);
+
+ /*
+ * Only check for timer-based work if
+ * something in the incoming RPC logic said
+ * to. This might be just a hack to avoid
+ * scanning the list unnecessarily, but I
+ * suspect it's also a hack to cover wrong
+ * state logic. - dholland 20140609
+ */
if (check)
checkwork();
break;
}
- if (!evil && domains->dom_alive) {
- evil = 1;
+ /*
+ * Defer daemonizing until the default domain binds
+ * successfully. XXX: there seems to be no timeout
+ * on this, which means that if the default domain
+ * is dead upstream boot will hang indefinitely.
+ */
+ if (!started && domains->dom_state == DOM_ALIVE) {
+ started = 1;
#ifdef DEBUG
if (!debug)
#endif
