glibc/sunrpc/clnt_udp.c
Florian Weimer cf0bd2f73b sunrpc: Improvements for UDP client timeout handling [BZ #20257]
This commit fixes various aspects in the UDP client timeout handling.
Timeouts are now applied in a more consistent fashion.  Discarded UDP
packets no longer prevent the timeout from happening at all.
2017-02-28 15:36:17 +01:00

646 lines
18 KiB
C

/*
* clnt_udp.c, Implements a UDP/IP based, client side RPC.
*
* Copyright (c) 2010, Oracle America, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
* * Neither the name of the "Oracle America, Inc." nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <unistd.h>
#include <libintl.h>
#include <rpc/rpc.h>
#include <rpc/xdr.h>
#include <rpc/clnt.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netdb.h>
#include <errno.h>
#include <stdint.h>
#include <rpc/pmap_clnt.h>
#include <net/if.h>
#include <ifaddrs.h>
#include <wchar.h>
#include <fcntl.h>
#ifdef IP_RECVERR
#include <errqueue.h>
#include <sys/uio.h>
#endif
#include <kernel-features.h>
#include <inet/net-internal.h>
extern u_long _create_xid (void);
/*
* UDP bases client side rpc operations
*/
static enum clnt_stat clntudp_call (CLIENT *, u_long, xdrproc_t, caddr_t,
xdrproc_t, caddr_t, struct timeval);
static void clntudp_abort (void);
static void clntudp_geterr (CLIENT *, struct rpc_err *);
static bool_t clntudp_freeres (CLIENT *, xdrproc_t, caddr_t);
static bool_t clntudp_control (CLIENT *, int, char *);
static void clntudp_destroy (CLIENT *);
static const struct clnt_ops udp_ops =
{
clntudp_call,
clntudp_abort,
clntudp_geterr,
clntudp_freeres,
clntudp_destroy,
clntudp_control
};
/*
* Private data kept per client handle. This private struct is
* unfortunately part of the ABI; ypbind contains a copy of it and
* accesses it through CLIENT::cl_private field.
*/
struct cu_data
{
int cu_sock;
bool_t cu_closeit;
struct sockaddr_in cu_raddr;
int cu_rlen;
struct timeval cu_wait;
struct timeval cu_total;
struct rpc_err cu_error;
XDR cu_outxdrs;
u_int cu_xdrpos;
u_int cu_sendsz;
char *cu_outbuf;
u_int cu_recvsz;
char cu_inbuf[1];
};
/*
* Create a UDP based client handle.
* If *sockp<0, *sockp is set to a newly created UPD socket.
* If raddr->sin_port is 0 a binder on the remote machine
* is consulted for the correct port number.
* NB: It is the clients responsibility to close *sockp.
* NB: The rpch->cl_auth is initialized to null authentication.
* Caller may wish to set this something more useful.
*
* wait is the amount of time used between retransmitting a call if
* no response has been heard; retransmission occurs until the actual
* rpc call times out.
*
* sendsz and recvsz are the maximum allowable packet sizes that can be
* sent and received.
*/
CLIENT *
__libc_clntudp_bufcreate (struct sockaddr_in *raddr, u_long program,
u_long version, struct timeval wait, int *sockp,
u_int sendsz, u_int recvsz, int flags)
{
CLIENT *cl;
struct cu_data *cu = NULL;
struct rpc_msg call_msg;
cl = (CLIENT *) mem_alloc (sizeof (CLIENT));
sendsz = ((sendsz + 3) / 4) * 4;
recvsz = ((recvsz + 3) / 4) * 4;
cu = (struct cu_data *) mem_alloc (sizeof (*cu) + sendsz + recvsz);
if (cl == NULL || cu == NULL)
{
struct rpc_createerr *ce = &get_rpc_createerr ();
(void) __fxprintf (NULL, "%s: %s",
"clntudp_create", _("out of memory\n"));
ce->cf_stat = RPC_SYSTEMERROR;
ce->cf_error.re_errno = ENOMEM;
goto fooy;
}
cu->cu_outbuf = &cu->cu_inbuf[recvsz];
if (raddr->sin_port == 0)
{
u_short port;
if ((port =
pmap_getport (raddr, program, version, IPPROTO_UDP)) == 0)
{
goto fooy;
}
raddr->sin_port = htons (port);
}
cl->cl_ops = (struct clnt_ops *) &udp_ops;
cl->cl_private = (caddr_t) cu;
cu->cu_raddr = *raddr;
cu->cu_rlen = sizeof (cu->cu_raddr);
cu->cu_wait = wait;
cu->cu_total.tv_sec = -1;
cu->cu_total.tv_usec = -1;
cu->cu_sendsz = sendsz;
cu->cu_recvsz = recvsz;
call_msg.rm_xid = _create_xid ();
call_msg.rm_direction = CALL;
call_msg.rm_call.cb_rpcvers = RPC_MSG_VERSION;
call_msg.rm_call.cb_prog = program;
call_msg.rm_call.cb_vers = version;
xdrmem_create (&(cu->cu_outxdrs), cu->cu_outbuf, sendsz, XDR_ENCODE);
if (!xdr_callhdr (&(cu->cu_outxdrs), &call_msg))
{
goto fooy;
}
cu->cu_xdrpos = XDR_GETPOS (&(cu->cu_outxdrs));
if (*sockp < 0)
{
*sockp = __socket (AF_INET, SOCK_DGRAM|SOCK_NONBLOCK|flags, IPPROTO_UDP);
if (__glibc_unlikely (*sockp < 0))
{
struct rpc_createerr *ce = &get_rpc_createerr ();
ce->cf_stat = RPC_SYSTEMERROR;
ce->cf_error.re_errno = errno;
goto fooy;
}
/* attempt to bind to prov port */
(void) bindresvport (*sockp, (struct sockaddr_in *) 0);
#ifdef IP_RECVERR
{
int on = 1;
__setsockopt (*sockp, SOL_IP, IP_RECVERR, &on, sizeof(on));
}
#endif
cu->cu_closeit = TRUE;
}
else
{
cu->cu_closeit = FALSE;
}
cu->cu_sock = *sockp;
cl->cl_auth = authnone_create ();
return cl;
fooy:
if (cu)
mem_free ((caddr_t) cu, sizeof (*cu) + sendsz + recvsz);
if (cl)
mem_free ((caddr_t) cl, sizeof (CLIENT));
return (CLIENT *) NULL;
}
#ifdef EXPORT_RPC_SYMBOLS
libc_hidden_def (__libc_clntudp_bufcreate)
#else
libc_hidden_nolink_sunrpc (__libc_clntudp_bufcreate, GLIBC_PRIVATE)
#endif
CLIENT *
clntudp_bufcreate (struct sockaddr_in *raddr, u_long program, u_long version,
struct timeval wait, int *sockp, u_int sendsz,
u_int recvsz)
{
return __libc_clntudp_bufcreate (raddr, program, version, wait,
sockp, sendsz, recvsz, 0);
}
libc_hidden_nolink_sunrpc (clntudp_bufcreate, GLIBC_2_0)
CLIENT *
clntudp_create (struct sockaddr_in *raddr, u_long program, u_long version,
struct timeval wait, int *sockp)
{
return __libc_clntudp_bufcreate (raddr, program, version, wait,
sockp, UDPMSGSIZE, UDPMSGSIZE, 0);
}
#ifdef EXPORT_RPC_SYMBOLS
libc_hidden_def (clntudp_create)
#else
libc_hidden_nolink_sunrpc (clntudp_create, GLIBC_2_0)
#endif
static int
is_network_up (int sock)
{
struct ifaddrs *ifa;
if (getifaddrs (&ifa) != 0)
return 0;
struct ifaddrs *run = ifa;
while (run != NULL)
{
if ((run->ifa_flags & IFF_UP) != 0
&& run->ifa_addr != NULL
&& run->ifa_addr->sa_family == AF_INET)
break;
run = run->ifa_next;
}
freeifaddrs (ifa);
return run != NULL;
}
static enum clnt_stat
clntudp_call (/* client handle */
CLIENT *cl,
/* procedure number */
u_long proc,
/* xdr routine for args */
xdrproc_t xargs,
/* pointer to args */
caddr_t argsp,
/* xdr routine for results */
xdrproc_t xresults,
/* pointer to results */
caddr_t resultsp,
/* seconds to wait before giving up */
struct timeval utimeout)
{
struct cu_data *cu = (struct cu_data *) cl->cl_private;
XDR *xdrs;
int outlen = 0;
int inlen;
socklen_t fromlen;
struct pollfd fd;
struct sockaddr_in from;
struct rpc_msg reply_msg;
XDR reply_xdrs;
bool_t ok;
int nrefreshes = 2; /* number of times to refresh cred */
int anyup; /* any network interface up */
struct deadline_current_time current_time = __deadline_current_time ();
struct deadline total_deadline; /* Determined once by overall timeout. */
struct deadline response_deadline; /* Determined anew for each query. */
/* Choose the timeout value. For non-sending usage (xargs == NULL),
the total deadline does not matter, only cu->cu_wait is used
below. */
if (xargs != NULL)
{
struct timeval tv;
if (cu->cu_total.tv_usec == -1)
/* Use supplied timeout. */
tv = utimeout;
else
/* Use default timeout. */
tv = cu->cu_total;
if (!__is_timeval_valid_timeout (tv))
return (cu->cu_error.re_status = RPC_TIMEDOUT);
total_deadline = __deadline_from_timeval (current_time, tv);
}
/* Guard against bad timeout specification. */
if (!__is_timeval_valid_timeout (cu->cu_wait))
return (cu->cu_error.re_status = RPC_TIMEDOUT);
call_again:
xdrs = &(cu->cu_outxdrs);
if (xargs == NULL)
goto get_reply;
xdrs->x_op = XDR_ENCODE;
XDR_SETPOS (xdrs, cu->cu_xdrpos);
/*
* the transaction is the first thing in the out buffer
*/
(*(uint32_t *) (cu->cu_outbuf))++;
if ((!XDR_PUTLONG (xdrs, (long *) &proc)) ||
(!AUTH_MARSHALL (cl->cl_auth, xdrs)) ||
(!(*xargs) (xdrs, argsp)))
return (cu->cu_error.re_status = RPC_CANTENCODEARGS);
outlen = (int) XDR_GETPOS (xdrs);
send_again:
if (__sendto (cu->cu_sock, cu->cu_outbuf, outlen, 0,
(struct sockaddr *) &(cu->cu_raddr), cu->cu_rlen)
!= outlen)
{
cu->cu_error.re_errno = errno;
return (cu->cu_error.re_status = RPC_CANTSEND);
}
/* sendto may have blocked, so recompute the current time. */
current_time = __deadline_current_time ();
get_reply:
response_deadline = __deadline_from_timeval (current_time, cu->cu_wait);
reply_msg.acpted_rply.ar_verf = _null_auth;
reply_msg.acpted_rply.ar_results.where = resultsp;
reply_msg.acpted_rply.ar_results.proc = xresults;
fd.fd = cu->cu_sock;
fd.events = POLLIN;
anyup = 0;
/* Per-response retry loop. current_time must be up-to-date at the
top of the loop. */
for (;;)
{
int milliseconds;
if (xargs != NULL)
{
if (__deadline_elapsed (current_time, total_deadline))
/* Overall timeout expired. */
return (cu->cu_error.re_status = RPC_TIMEDOUT);
milliseconds = __deadline_to_ms
(current_time, __deadline_first (total_deadline,
response_deadline));
if (milliseconds == 0)
/* Per-query timeout expired. */
goto send_again;
}
else
{
/* xatgs == NULL. Collect a response without sending a
query. In this mode, we need to ignore the total
deadline. */
milliseconds = __deadline_to_ms (current_time, response_deadline);
if (milliseconds == 0)
/* Cannot send again, so bail out. */
return (cu->cu_error.re_status = RPC_CANTSEND);
}
switch (__poll (&fd, 1, milliseconds))
{
case 0:
if (anyup == 0)
{
anyup = is_network_up (cu->cu_sock);
if (!anyup)
return (cu->cu_error.re_status = RPC_CANTRECV);
}
goto next_response;
case -1:
if (errno == EINTR)
goto next_response;
cu->cu_error.re_errno = errno;
return (cu->cu_error.re_status = RPC_CANTRECV);
}
#ifdef IP_RECVERR
if (fd.revents & POLLERR)
{
struct msghdr msg;
struct cmsghdr *cmsg;
struct sock_extended_err *e;
struct sockaddr_in err_addr;
struct iovec iov;
char *cbuf = malloc (outlen + 256);
int ret;
if (cbuf == NULL)
{
cu->cu_error.re_errno = errno;
return (cu->cu_error.re_status = RPC_CANTRECV);
}
iov.iov_base = cbuf + 256;
iov.iov_len = outlen;
msg.msg_name = (void *) &err_addr;
msg.msg_namelen = sizeof (err_addr);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_flags = 0;
msg.msg_control = cbuf;
msg.msg_controllen = 256;
ret = __recvmsg (cu->cu_sock, &msg, MSG_ERRQUEUE);
if (ret >= 0
&& memcmp (cbuf + 256, cu->cu_outbuf, ret) == 0
&& (msg.msg_flags & MSG_ERRQUEUE)
&& ((msg.msg_namelen == 0
&& ret >= 12)
|| (msg.msg_namelen == sizeof (err_addr)
&& err_addr.sin_family == AF_INET
&& memcmp (&err_addr.sin_addr, &cu->cu_raddr.sin_addr,
sizeof (err_addr.sin_addr)) == 0
&& err_addr.sin_port == cu->cu_raddr.sin_port)))
for (cmsg = CMSG_FIRSTHDR (&msg); cmsg;
cmsg = CMSG_NXTHDR (&msg, cmsg))
if (cmsg->cmsg_level == SOL_IP && cmsg->cmsg_type == IP_RECVERR)
{
e = (struct sock_extended_err *) CMSG_DATA(cmsg);
cu->cu_error.re_errno = e->ee_errno;
free (cbuf);
return (cu->cu_error.re_status = RPC_CANTRECV);
}
free (cbuf);
}
#endif
do
{
fromlen = sizeof (struct sockaddr);
inlen = __recvfrom (cu->cu_sock, cu->cu_inbuf,
(int) cu->cu_recvsz, MSG_DONTWAIT,
(struct sockaddr *) &from, &fromlen);
}
while (inlen < 0 && errno == EINTR);
if (inlen < 0)
{
if (errno == EWOULDBLOCK)
goto next_response;
cu->cu_error.re_errno = errno;
return (cu->cu_error.re_status = RPC_CANTRECV);
}
/* Accept the response if the packet is sufficiently long and
the transaction ID matches the query (if available). */
if (inlen >= 4
&& (xargs == NULL
|| memcmp (cu->cu_inbuf, cu->cu_outbuf,
sizeof (u_int32_t)) == 0))
break;
next_response:
/* Update the current time because poll and recvmsg waited for
an unknown time. */
current_time = __deadline_current_time ();
}
/*
* now decode and validate the response
*/
xdrmem_create (&reply_xdrs, cu->cu_inbuf, (u_int) inlen, XDR_DECODE);
ok = xdr_replymsg (&reply_xdrs, &reply_msg);
/* XDR_DESTROY(&reply_xdrs); save a few cycles on noop destroy */
if (ok)
{
_seterr_reply (&reply_msg, &(cu->cu_error));
if (cu->cu_error.re_status == RPC_SUCCESS)
{
if (!AUTH_VALIDATE (cl->cl_auth,
&reply_msg.acpted_rply.ar_verf))
{
cu->cu_error.re_status = RPC_AUTHERROR;
cu->cu_error.re_why = AUTH_INVALIDRESP;
}
if (reply_msg.acpted_rply.ar_verf.oa_base != NULL)
{
xdrs->x_op = XDR_FREE;
(void) xdr_opaque_auth (xdrs, &(reply_msg.acpted_rply.ar_verf));
}
} /* end successful completion */
else
{
/* maybe our credentials need to be refreshed ... */
if (nrefreshes > 0 && AUTH_REFRESH (cl->cl_auth))
{
nrefreshes--;
goto call_again;
}
} /* end of unsuccessful completion */
} /* end of valid reply message */
else
{
cu->cu_error.re_status = RPC_CANTDECODERES;
}
return cu->cu_error.re_status;
}
static void
clntudp_geterr (CLIENT *cl, struct rpc_err *errp)
{
struct cu_data *cu = (struct cu_data *) cl->cl_private;
*errp = cu->cu_error;
}
static bool_t
clntudp_freeres (CLIENT *cl, xdrproc_t xdr_res, caddr_t res_ptr)
{
struct cu_data *cu = (struct cu_data *) cl->cl_private;
XDR *xdrs = &(cu->cu_outxdrs);
xdrs->x_op = XDR_FREE;
return (*xdr_res) (xdrs, res_ptr);
}
static void
clntudp_abort (void)
{
}
static bool_t
clntudp_control (CLIENT *cl, int request, char *info)
{
struct cu_data *cu = (struct cu_data *) cl->cl_private;
u_long ul;
u_int32_t ui32;
switch (request)
{
case CLSET_FD_CLOSE:
cu->cu_closeit = TRUE;
break;
case CLSET_FD_NCLOSE:
cu->cu_closeit = FALSE;
break;
case CLSET_TIMEOUT:
cu->cu_total = *(struct timeval *) info;
break;
case CLGET_TIMEOUT:
*(struct timeval *) info = cu->cu_total;
break;
case CLSET_RETRY_TIMEOUT:
cu->cu_wait = *(struct timeval *) info;
break;
case CLGET_RETRY_TIMEOUT:
*(struct timeval *) info = cu->cu_wait;
break;
case CLGET_SERVER_ADDR:
*(struct sockaddr_in *) info = cu->cu_raddr;
break;
case CLGET_FD:
*(int *)info = cu->cu_sock;
break;
case CLGET_XID:
/*
* use the knowledge that xid is the
* first element in the call structure *.
* This will get the xid of the PREVIOUS call
*/
memcpy (&ui32, cu->cu_outbuf, sizeof (ui32));
ul = ntohl (ui32);
memcpy (info, &ul, sizeof (ul));
break;
case CLSET_XID:
/* This will set the xid of the NEXT call */
memcpy (&ul, info, sizeof (ul));
ui32 = htonl (ul - 1);
memcpy (cu->cu_outbuf, &ui32, sizeof (ui32));
/* decrement by 1 as clntudp_call() increments once */
break;
case CLGET_VERS:
/*
* This RELIES on the information that, in the call body,
* the version number field is the fifth field from the
* beginning of the RPC header. MUST be changed if the
* call_struct is changed
*/
memcpy (&ui32, cu->cu_outbuf + 4 * BYTES_PER_XDR_UNIT, sizeof (ui32));
ul = ntohl (ui32);
memcpy (info, &ul, sizeof (ul));
break;
case CLSET_VERS:
memcpy (&ul, info, sizeof (ul));
ui32 = htonl (ul);
memcpy (cu->cu_outbuf + 4 * BYTES_PER_XDR_UNIT, &ui32, sizeof (ui32));
break;
case CLGET_PROG:
/*
* This RELIES on the information that, in the call body,
* the program number field is the field from the
* beginning of the RPC header. MUST be changed if the
* call_struct is changed
*/
memcpy (&ui32, cu->cu_outbuf + 3 * BYTES_PER_XDR_UNIT, sizeof (ui32));
ul = ntohl (ui32);
memcpy (info, &ul, sizeof (ul));
break;
case CLSET_PROG:
memcpy (&ul, info, sizeof (ul));
ui32 = htonl (ul);
memcpy (cu->cu_outbuf + 3 * BYTES_PER_XDR_UNIT, &ui32, sizeof (ui32));
break;
/* The following are only possible with TI-RPC */
case CLGET_SVC_ADDR:
case CLSET_SVC_ADDR:
case CLSET_PUSH_TIMOD:
case CLSET_POP_TIMOD:
default:
return FALSE;
}
return TRUE;
}
static void
clntudp_destroy (CLIENT *cl)
{
struct cu_data *cu = (struct cu_data *) cl->cl_private;
if (cu->cu_closeit)
{
(void) __close (cu->cu_sock);
}
XDR_DESTROY (&(cu->cu_outxdrs));
mem_free ((caddr_t) cu, (sizeof (*cu) + cu->cu_sendsz + cu->cu_recvsz));
mem_free ((caddr_t) cl, sizeof (CLIENT));
}