| Message ID | 20220701144422.328923-1-rbergant@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | rpcb_clnt.c add mechanism to try v2 protocol first | expand |
On 7/1/22 9:44 AM, Roberto Bergantinos Corpas wrote: > There have been previous attempts to revert protocol tryout > algorithm from v4,v3,v2 to previous v2,v4,v3 : > > https://www.spinics.net/lists/linux-nfs/msg89228.html > > Apart from GETADDR/NAT issue originating that proposed change, > its possible that some legacy custom applications still use > v2 of protocol with libtirpc. > > The change proposed here, introduces an environment variable > "RPCB_V2FIRST" so that, if defined, old behaviour is used. > This is more flexible and allow us to selectively pick what > application reverts to old behaviour instead of a system-wide > change. > > Example : > > $ tcpdump -s0 -i ens3 port 111 -w /tmp/capture.pcap &> /dev/null & > [1] 13016 > $ rpcinfo -T tcp 172.23.1.225 100005 &> /dev/null > $ RPCB_V2FIRST=1 rpcinfo -T tcp 172.23.1.225 100005 &> /dev/null > $ pkill tcpdump > $ tshark -tad -nr /tmp/capture.pcap -Y portmap -T fields -e _ws.col.Info > V4 GETADDR Call > V4 GETADDR Reply (Call In 4) > V2 GETPORT Call MOUNT(100005) V:0 TCP > V2 GETPORT Reply (Call In 14) Port:20048 > > Signed-off-by: Roberto Bergantinos Corpas <rbergant@redhat.com> Committed... (tag libtirpc-1-3-3-rc3) steved. > --- > man/rpcbind.3t | 2 ++ > src/rpcb_clnt.c | 27 ++++++++++++++++++++++++--- > tirpc/rpc/pmap_prot.h | 2 ++ > 3 files changed, 28 insertions(+), 3 deletions(-) > > diff --git a/man/rpcbind.3t b/man/rpcbind.3t > index ec492cc..4cb271b 100644 > --- a/man/rpcbind.3t > +++ b/man/rpcbind.3t > @@ -187,6 +187,8 @@ in > .El > .Sh AVAILABILITY > These functions are part of libtirpc. > +.Sh ENVIRONMENT > +If RPCB_V2FIRST is defined, rpcbind protocol version tryout algorithm changes from v4,v2,v3 to v2,v4,v3. > .Sh SEE ALSO > .Xr rpc_clnt_calls 3 , > .Xr rpc_svc_calls 3 , > diff --git a/src/rpcb_clnt.c b/src/rpcb_clnt.c > index 0c34cb7..db3799e 100644 > --- a/src/rpcb_clnt.c > +++ b/src/rpcb_clnt.c > @@ -818,7 +818,8 @@ error: > * The algorithm used: If the transports is TCP or UDP, it first tries > * version 4 (srv4), then 3 and then fall back to version 2 (portmap). > * With this algorithm, we get performance as well as a plan for > - * obsoleting version 2. > + * obsoleting version 2. This behaviour is reverted to old algorithm > + * if RPCB_V2FIRST environment var is defined > * > * For all other transports, the algorithm remains as 4 and then 3. > * > @@ -839,6 +840,10 @@ __rpcb_findaddr_timed(program, version, nconf, host, clpp, tp) > #ifdef NOTUSED > static bool_t check_rpcbind = TRUE; > #endif > + > +#ifdef PORTMAP > + static bool_t portmap_first = FALSE; > +#endif > CLIENT *client = NULL; > RPCB parms; > enum clnt_stat clnt_st; > @@ -895,8 +900,18 @@ __rpcb_findaddr_timed(program, version, nconf, host, clpp, tp) > parms.r_addr = (char *) &nullstring[0]; > } > > - /* First try from start_vers(4) and then version 3 (RPCBVERS) */ > + /* First try from start_vers(4) and then version 3 (RPCBVERS), except > + * if env. var RPCB_V2FIRST is defined */ > + > +#ifdef PORTMAP > + if (getenv(V2FIRST)) { > + portmap_first = TRUE; > + LIBTIRPC_DEBUG(3, ("__rpcb_findaddr_timed: trying v2-port first\n")); > + goto portmap; > + } > +#endif > > +rpcbind: > CLNT_CONTROL(client, CLSET_RETRY_TIMEOUT, (char *) &rpcbrmttime); > for (vers = start_vers; vers >= RPCBVERS; vers--) { > /* Set the version */ > @@ -944,10 +959,16 @@ __rpcb_findaddr_timed(program, version, nconf, host, clpp, tp) > } > > #ifdef PORTMAP /* Try version 2 for TCP or UDP */ > + if (portmap_first) > + goto error; /* we tried all versions if reached here */ > +portmap: > if (strcmp(nconf->nc_protofmly, NC_INET) == 0) { > address = __try_protocol_version_2(program, version, nconf, host, tp); > if (address == NULL) > - goto error; > + if (portmap_first) > + goto rpcbind; > + else > + goto error; > } > #endif /* PORTMAP */ > > diff --git a/tirpc/rpc/pmap_prot.h b/tirpc/rpc/pmap_prot.h > index 75354ce..7718b8b 100644 > --- a/tirpc/rpc/pmap_prot.h > +++ b/tirpc/rpc/pmap_prot.h > @@ -84,6 +84,8 @@ > #define PMAPPROC_DUMP ((u_long)4) > #define PMAPPROC_CALLIT ((u_long)5) > > +#define V2FIRST "RPCB_V2FIRST" > + > struct pmap { > long unsigned pm_prog; > long unsigned pm_vers;
diff --git a/man/rpcbind.3t b/man/rpcbind.3t index ec492cc..4cb271b 100644 --- a/man/rpcbind.3t +++ b/man/rpcbind.3t @@ -187,6 +187,8 @@ in .El .Sh AVAILABILITY These functions are part of libtirpc. +.Sh ENVIRONMENT +If RPCB_V2FIRST is defined, rpcbind protocol version tryout algorithm changes from v4,v2,v3 to v2,v4,v3. .Sh SEE ALSO .Xr rpc_clnt_calls 3 , .Xr rpc_svc_calls 3 , diff --git a/src/rpcb_clnt.c b/src/rpcb_clnt.c index 0c34cb7..db3799e 100644 --- a/src/rpcb_clnt.c +++ b/src/rpcb_clnt.c @@ -818,7 +818,8 @@ error: * The algorithm used: If the transports is TCP or UDP, it first tries * version 4 (srv4), then 3 and then fall back to version 2 (portmap). * With this algorithm, we get performance as well as a plan for - * obsoleting version 2. + * obsoleting version 2. This behaviour is reverted to old algorithm + * if RPCB_V2FIRST environment var is defined * * For all other transports, the algorithm remains as 4 and then 3. * @@ -839,6 +840,10 @@ __rpcb_findaddr_timed(program, version, nconf, host, clpp, tp) #ifdef NOTUSED static bool_t check_rpcbind = TRUE; #endif + +#ifdef PORTMAP + static bool_t portmap_first = FALSE; +#endif CLIENT *client = NULL; RPCB parms; enum clnt_stat clnt_st; @@ -895,8 +900,18 @@ __rpcb_findaddr_timed(program, version, nconf, host, clpp, tp) parms.r_addr = (char *) &nullstring[0]; } - /* First try from start_vers(4) and then version 3 (RPCBVERS) */ + /* First try from start_vers(4) and then version 3 (RPCBVERS), except + * if env. var RPCB_V2FIRST is defined */ + +#ifdef PORTMAP + if (getenv(V2FIRST)) { + portmap_first = TRUE; + LIBTIRPC_DEBUG(3, ("__rpcb_findaddr_timed: trying v2-port first\n")); + goto portmap; + } +#endif +rpcbind: CLNT_CONTROL(client, CLSET_RETRY_TIMEOUT, (char *) &rpcbrmttime); for (vers = start_vers; vers >= RPCBVERS; vers--) { /* Set the version */ @@ -944,10 +959,16 @@ __rpcb_findaddr_timed(program, version, nconf, host, clpp, tp) } #ifdef PORTMAP /* Try version 2 for TCP or UDP */ + if (portmap_first) + goto error; /* we tried all versions if reached here */ +portmap: if (strcmp(nconf->nc_protofmly, NC_INET) == 0) { address = __try_protocol_version_2(program, version, nconf, host, tp); if (address == NULL) - goto error; + if (portmap_first) + goto rpcbind; + else + goto error; } #endif /* PORTMAP */ diff --git a/tirpc/rpc/pmap_prot.h b/tirpc/rpc/pmap_prot.h index 75354ce..7718b8b 100644 --- a/tirpc/rpc/pmap_prot.h +++ b/tirpc/rpc/pmap_prot.h @@ -84,6 +84,8 @@ #define PMAPPROC_DUMP ((u_long)4) #define PMAPPROC_CALLIT ((u_long)5) +#define V2FIRST "RPCB_V2FIRST" + struct pmap { long unsigned pm_prog; long unsigned pm_vers;
There have been previous attempts to revert protocol tryout algorithm from v4,v3,v2 to previous v2,v4,v3 : https://www.spinics.net/lists/linux-nfs/msg89228.html Apart from GETADDR/NAT issue originating that proposed change, its possible that some legacy custom applications still use v2 of protocol with libtirpc. The change proposed here, introduces an environment variable "RPCB_V2FIRST" so that, if defined, old behaviour is used. This is more flexible and allow us to selectively pick what application reverts to old behaviour instead of a system-wide change. Example : $ tcpdump -s0 -i ens3 port 111 -w /tmp/capture.pcap &> /dev/null & [1] 13016 $ rpcinfo -T tcp 172.23.1.225 100005 &> /dev/null $ RPCB_V2FIRST=1 rpcinfo -T tcp 172.23.1.225 100005 &> /dev/null $ pkill tcpdump $ tshark -tad -nr /tmp/capture.pcap -Y portmap -T fields -e _ws.col.Info V4 GETADDR Call V4 GETADDR Reply (Call In 4) V2 GETPORT Call MOUNT(100005) V:0 TCP V2 GETPORT Reply (Call In 14) Port:20048 Signed-off-by: Roberto Bergantinos Corpas <rbergant@redhat.com> --- man/rpcbind.3t | 2 ++ src/rpcb_clnt.c | 27 ++++++++++++++++++++++++--- tirpc/rpc/pmap_prot.h | 2 ++ 3 files changed, 28 insertions(+), 3 deletions(-)