| Message ID | 20180410213043.5545-1-steved@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> On Apr 10, 2018, at 3:30 PM, Steve Dickson <steved@redhat.com> wrote: > > Commit 46e04a73 changed both clnt_com_create() > and clnt_tli_create() to avoid using reserve ports when > creating connection to the server. > > For certain legacy apps, the client has to used > reserve port to be able to communicate with its > server so using of reserve ports is restored. Hi Steve- Which legacy apps use clnt_tli_create and require this behavior? There is no backwards compatibility requirement for this API. > Signed-off-by: Steve Dickson <steved@redhat.com> > --- > src/clnt_generic.c | 3 +-- > src/rpc_soc.c | 3 +-- > 2 files changed, 2 insertions(+), 4 deletions(-) > > diff --git a/src/clnt_generic.c b/src/clnt_generic.c > index e5a314f..774292b 100644 > --- a/src/clnt_generic.c > +++ b/src/clnt_generic.c > @@ -341,8 +341,7 @@ clnt_tli_create(int fd, const struct netconfig *nconf, > servtype = nconf->nc_semantics; > if (!__rpc_fd2sockinfo(fd, &si)) > goto err; > - if (__binddynport(fd) == -1) > - goto err; > + bindresvport(fd, NULL); > } else { > if (!__rpc_fd2sockinfo(fd, &si)) > goto err; > diff --git a/src/rpc_soc.c b/src/rpc_soc.c > index af6c482..f32a27c 100644 > --- a/src/rpc_soc.c > +++ b/src/rpc_soc.c > @@ -147,8 +147,7 @@ clnt_com_create(raddr, prog, vers, sockp, sendsz, recvsz, tp, flags) > bindaddr.maxlen = bindaddr.len = sizeof (struct sockaddr_in); > bindaddr.buf = raddr; > > - if (__binddynport(fd) == -1) > - goto err; > + bindresvport(fd, NULL); > cl = clnt_tli_create(fd, nconf, &bindaddr, prog, vers, > sendsz, recvsz); > if (cl) { > -- > 2.14.3 > > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Libtirpc-devel mailing list > Libtirpc-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/libtirpc-devel -- Chuck Lever -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hey, On 04/10/2018 06:17 PM, Chuck Lever wrote: > > >> On Apr 10, 2018, at 3:30 PM, Steve Dickson <steved@redhat.com> wrote: >> >> Commit 46e04a73 changed both clnt_com_create() >> and clnt_tli_create() to avoid using reserve ports when >> creating connection to the server. >> >> For certain legacy apps, the client has to used >> reserve port to be able to communicate with its >> server so using of reserve ports is restored. > > Hi Steve- > > Which legacy apps use clnt_tli_create and require this behavior? yphelper, yppush and ypxfr via the clnt_create() call. At least that's all I have found so far. > There is no backwards compatibility requirement for this API. Well unlike the server side, the client will not be squatting on these port for an absorbent amount time. 99% of the time they are UDP connection so the ports are immediately reusable, unlike TCP connection that get stuck in TIME_WAIT and there is a requirement for reserve port be used to talk to the server. So I'm feeling pretty strong that there is no problem at all with the client using reserve ports for their short lived connection. Not using them would cause more problems as we have already seen. steved. > > >> Signed-off-by: Steve Dickson <steved@redhat.com> >> --- >> src/clnt_generic.c | 3 +-- >> src/rpc_soc.c | 3 +-- >> 2 files changed, 2 insertions(+), 4 deletions(-) >> >> diff --git a/src/clnt_generic.c b/src/clnt_generic.c >> index e5a314f..774292b 100644 >> --- a/src/clnt_generic.c >> +++ b/src/clnt_generic.c >> @@ -341,8 +341,7 @@ clnt_tli_create(int fd, const struct netconfig *nconf, >> servtype = nconf->nc_semantics; >> if (!__rpc_fd2sockinfo(fd, &si)) >> goto err; >> - if (__binddynport(fd) == -1) >> - goto err; >> + bindresvport(fd, NULL); >> } else { >> if (!__rpc_fd2sockinfo(fd, &si)) >> goto err; >> diff --git a/src/rpc_soc.c b/src/rpc_soc.c >> index af6c482..f32a27c 100644 >> --- a/src/rpc_soc.c >> +++ b/src/rpc_soc.c >> @@ -147,8 +147,7 @@ clnt_com_create(raddr, prog, vers, sockp, sendsz, recvsz, tp, flags) >> bindaddr.maxlen = bindaddr.len = sizeof (struct sockaddr_in); >> bindaddr.buf = raddr; >> >> - if (__binddynport(fd) == -1) >> - goto err; >> + bindresvport(fd, NULL); >> cl = clnt_tli_create(fd, nconf, &bindaddr, prog, vers, >> sendsz, recvsz); >> if (cl) { >> -- >> 2.14.3 >> >> >> ------------------------------------------------------------------------------ >> Check out the vibrant tech community on one of the world's most >> engaging tech sites, Slashdot.org! http://sdm.link/slashdot >> _______________________________________________ >> Libtirpc-devel mailing list >> Libtirpc-devel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/libtirpc-devel > > -- > Chuck Lever > > > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Apr 11, Steve Dickson wrote: > > Hey, > > On 04/10/2018 06:17 PM, Chuck Lever wrote: > > > > > >> On Apr 10, 2018, at 3:30 PM, Steve Dickson <steved@redhat.com> wrote: > >> > >> Commit 46e04a73 changed both clnt_com_create() > >> and clnt_tli_create() to avoid using reserve ports when > >> creating connection to the server. > >> > >> For certain legacy apps, the client has to used > >> reserve port to be able to communicate with its > >> server so using of reserve ports is restored. > > > > Hi Steve- > > > > Which legacy apps use clnt_tli_create and require this behavior? > yphelper, yppush and ypxfr via the clnt_create() call. At least > that's all I have found so far. Yes, and I need to change that like Solaris is doing it, only a question of time on my side :( Thorsten
On 04/11/2018 08:59 AM, Thorsten Kukuk wrote: > On Wed, Apr 11, Steve Dickson wrote: > >> >> Hey, >> >> On 04/10/2018 06:17 PM, Chuck Lever wrote: >>> >>> >>>> On Apr 10, 2018, at 3:30 PM, Steve Dickson <steved@redhat.com> wrote: >>>> >>>> Commit 46e04a73 changed both clnt_com_create() >>>> and clnt_tli_create() to avoid using reserve ports when >>>> creating connection to the server. >>>> >>>> For certain legacy apps, the client has to used >>>> reserve port to be able to communicate with its >>>> server so using of reserve ports is restored. >>> >>> Hi Steve- >>> >>> Which legacy apps use clnt_tli_create and require this behavior? >> yphelper, yppush and ypxfr via the clnt_create() call. At least >> that's all I have found so far. > Add rpcinfo to this list... Its used in the remote call code. steved. > Yes, and I need to change that like Solaris is doing it, only a > question of time on my side :( > > Thorsten > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> On Apr 11, 2018, at 6:34 AM, Steve Dickson <SteveD@RedHat.com> wrote: > > > Hey, > > On 04/10/2018 06:17 PM, Chuck Lever wrote: >> >> >>> On Apr 10, 2018, at 3:30 PM, Steve Dickson <steved@redhat.com> wrote: >>> >>> Commit 46e04a73 changed both clnt_com_create() >>> and clnt_tli_create() to avoid using reserve ports when >>> creating connection to the server. >>> >>> For certain legacy apps, the client has to used >>> reserve port to be able to communicate with its >>> server so using of reserve ports is restored. >> >> Hi Steve- >> >> Which legacy apps use clnt_tli_create and require this behavior? > yphelper, yppush and ypxfr via the clnt_create() call. At least > that's all I have found so far. clnt_create(3) unfortunately appears to be in glibc. So fair enough, but your patch description really does need to provide these details and examples, please. >> There is no backwards compatibility requirement for this API. > Well unlike the server side, the client will not be squatting > on these port for an absorbent amount time. 99% of the time they > are UDP connection so the ports are immediately reusable, > unlike TCP connection that get stuck in TIME_WAIT and > there is a requirement for reserve port be used to talk > to the server. I do not agree that this is a harmless default. There is no guarantee that the RPC consumer is going to release the client immediately. That's the problem with continuing to use bindresvport(3) here: many callers might free the CLNT immediately, but some don't. We have examples of callers -- in our own administrative tools -- that start up as root on purpose so they can create a long-lived client. Some of them don't need to do that, and thus can consume a reserved port for no good reason. And we know that a few applications do use TCP, even for short-lived clients, and that has a bad side-effect. Look at mount.nfs, for example. It runs as root. If it uses TCP to contact the server's rpcbind and mountd, and uses these basic library client APIs, that leaves two reserved ports in TIME_WAIT for two minutes. A storm of NFS mount operations can easily consume all the reserved ports for a few minutes. Maybe mount.nfs doesn't do that, but some other applications might. There's nothing in libtirpc to prevent it. > So I'm feeling pretty strong that there is no problem at > all with the client using reserve ports for their short > lived connection. There is no guarantee the client will be short-lived, and in the common case a reserved port is an unneeded use of a scarce system resource. This is bad default behavior. > Not using them would cause more problems > as we have already seen. This is not "causing problems." These legacy apps are using an undocumented behavior. I will note that we are basically fixing libtirpc to address an application where patches are available for this to be done correctly. The best that can be done for the moment is try to reduce the likelihood that bindresvport(3) will land on a well-known port, without reducing the reliability of success. I will look into it. > steved. > >> >> >>> Signed-off-by: Steve Dickson <steved@redhat.com> >>> --- >>> src/clnt_generic.c | 3 +-- >>> src/rpc_soc.c | 3 +-- >>> 2 files changed, 2 insertions(+), 4 deletions(-) >>> >>> diff --git a/src/clnt_generic.c b/src/clnt_generic.c >>> index e5a314f..774292b 100644 >>> --- a/src/clnt_generic.c >>> +++ b/src/clnt_generic.c >>> @@ -341,8 +341,7 @@ clnt_tli_create(int fd, const struct netconfig *nconf, >>> servtype = nconf->nc_semantics; >>> if (!__rpc_fd2sockinfo(fd, &si)) >>> goto err; >>> - if (__binddynport(fd) == -1) >>> - goto err; >>> + bindresvport(fd, NULL); >>> } else { >>> if (!__rpc_fd2sockinfo(fd, &si)) >>> goto err; >>> diff --git a/src/rpc_soc.c b/src/rpc_soc.c >>> index af6c482..f32a27c 100644 >>> --- a/src/rpc_soc.c >>> +++ b/src/rpc_soc.c >>> @@ -147,8 +147,7 @@ clnt_com_create(raddr, prog, vers, sockp, sendsz, recvsz, tp, flags) >>> bindaddr.maxlen = bindaddr.len = sizeof (struct sockaddr_in); >>> bindaddr.buf = raddr; >>> >>> - if (__binddynport(fd) == -1) >>> - goto err; >>> + bindresvport(fd, NULL); >>> cl = clnt_tli_create(fd, nconf, &bindaddr, prog, vers, >>> sendsz, recvsz); >>> if (cl) { >>> -- >>> 2.14.3 >>> >>> >>> ------------------------------------------------------------------------------ >>> Check out the vibrant tech community on one of the world's most >>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot >>> _______________________________________________ >>> Libtirpc-devel mailing list >>> Libtirpc-devel@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/libtirpc-devel >> >> -- >> Chuck Lever >> >> >> -- Chuck Lever -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> On Apr 11, 2018, at 8:07 AM, Steve Dickson <SteveD@RedHat.com> wrote: > > > > On 04/11/2018 08:59 AM, Thorsten Kukuk wrote: >> On Wed, Apr 11, Steve Dickson wrote: >> >>> >>> Hey, >>> >>> On 04/10/2018 06:17 PM, Chuck Lever wrote: >>>> >>>> >>>>> On Apr 10, 2018, at 3:30 PM, Steve Dickson <steved@redhat.com> wrote: >>>>> >>>>> Commit 46e04a73 changed both clnt_com_create() >>>>> and clnt_tli_create() to avoid using reserve ports when >>>>> creating connection to the server. >>>>> >>>>> For certain legacy apps, the client has to used >>>>> reserve port to be able to communicate with its >>>>> server so using of reserve ports is restored. >>>> >>>> Hi Steve- >>>> >>>> Which legacy apps use clnt_tli_create and require this behavior? >>> yphelper, yppush and ypxfr via the clnt_create() call. At least >>> that's all I have found so far. >> > Add rpcinfo to this list... Its used in the remote call code. clnt_create(3) is used there, but does it require a reserved port? > steved. > >> Yes, and I need to change that like Solaris is doing it, only a >> question of time on my side :( >> >> Thorsten >> > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Libtirpc-devel mailing list > Libtirpc-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/libtirpc-devel -- Chuck Lever chucklever@gmail.com -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/src/clnt_generic.c b/src/clnt_generic.c index e5a314f..774292b 100644 --- a/src/clnt_generic.c +++ b/src/clnt_generic.c @@ -341,8 +341,7 @@ clnt_tli_create(int fd, const struct netconfig *nconf, servtype = nconf->nc_semantics; if (!__rpc_fd2sockinfo(fd, &si)) goto err; - if (__binddynport(fd) == -1) - goto err; + bindresvport(fd, NULL); } else { if (!__rpc_fd2sockinfo(fd, &si)) goto err; diff --git a/src/rpc_soc.c b/src/rpc_soc.c index af6c482..f32a27c 100644 --- a/src/rpc_soc.c +++ b/src/rpc_soc.c @@ -147,8 +147,7 @@ clnt_com_create(raddr, prog, vers, sockp, sendsz, recvsz, tp, flags) bindaddr.maxlen = bindaddr.len = sizeof (struct sockaddr_in); bindaddr.buf = raddr; - if (__binddynport(fd) == -1) - goto err; + bindresvport(fd, NULL); cl = clnt_tli_create(fd, nconf, &bindaddr, prog, vers, sendsz, recvsz); if (cl) {
Commit 46e04a73 changed both clnt_com_create() and clnt_tli_create() to avoid using reserve ports when creating connection to the server. For certain legacy apps, the client has to used reserve port to be able to communicate with its server so using of reserve ports is restored. Signed-off-by: Steve Dickson <steved@redhat.com> --- src/clnt_generic.c | 3 +-- src/rpc_soc.c | 3 +-- 2 files changed, 2 insertions(+), 4 deletions(-)