[PATCH 01/24] libnsm.a: Add RPC construction helper functions

[Chuck Lever <chuck.lever@oracle.com>]

To manage concurrency, both statd and sm-notify construct raw RPC
requests in socket buffers, and use a minimal request scheduler
to send these requests and manage replies.  Both statd and sm-notify
open code the RPC request construction.

Introduce helper functions that can construct and send raw
NSMPROC_NOTIFY, NLM downcalls, and portmapper calls over a datagram
socket, and receive and parse their replies.  Support for IPv6 and
RPCB_GETADDR is featured.  This code (and the IPv6 support it
introduces) can now be shared by statd and sm-notify, eliminating
code and bug duplication.

This implementation is based on what's in utils/statd/rmtcall.c now,
but is wrapped up in a nice API and includes extra error checking.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---

 support/include/nsm.h   |   25 ++
 support/nsm/Makefile.am |    2 
 support/nsm/rpc.c       |  534 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 560 insertions(+), 1 deletions(-)
 create mode 100644 support/nsm/rpc.c

diff --git a/support/include/nsm.h b/support/include/nsm.h
index 28314d1..ce9e294 100644
--- a/support/include/nsm.h
+++ b/support/include/nsm.h
@@ -63,4 +63,29 @@ extern void	nsm_delete_notified_host(const char *hostname);
 extern size_t	nsm_priv_to_hex(const char *priv, char *buf,
 				const size_t buflen);
 
+/* rpc.c */
+
+#define NSM_MAXMSGSIZE	(2048u)
+
+extern uint32_t nsm_xmit_getport(const int sock,
+			const struct sockaddr_in *sin,
+			const unsigned long program,
+			const unsigned long version);
+extern uint32_t nsm_xmit_getaddr(const int sock,
+			const struct sockaddr_in6 *sin6,
+			const rpcprog_t program, const rpcvers_t version);
+extern uint32_t nsm_xmit_rpcbind(const int sock, const struct sockaddr *sap,
+			const rpcprog_t program, const rpcvers_t version);
+extern uint32_t nsm_xmit_notify(const int sock, const struct sockaddr *sap,
+			const socklen_t salen, const rpcprog_t program,
+			const char *mon_name, const int state);
+extern uint32_t nsm_xmit_nlmcall(const int sock, const struct sockaddr *sap,
+			const socklen_t salen, const struct mon *m,
+			const int state);
+extern uint32_t nsm_parse_reply(XDR *xdrs);
+extern unsigned long
+		nsm_recv_getport(XDR *xdrs);
+extern uint16_t nsm_recv_getaddr(XDR *xdrs);
+extern uint16_t nsm_recv_rpcbind(const sa_family_t family, XDR *xdrs);
+
 #endif	/* !NFS_UTILS_SUPPORT_NSM_H */
diff --git a/support/nsm/Makefile.am b/support/nsm/Makefile.am
index e359a43..2038e68 100644
--- a/support/nsm/Makefile.am
+++ b/support/nsm/Makefile.am
@@ -10,7 +10,7 @@ GENFILES	= $(GENFILES_CLNT) $(GENFILES_SVC) $(GENFILES_XDR) $(GENFILES_H)
 EXTRA_DIST	= sm_inter.x
 
 noinst_LIBRARIES = libnsm.a
-libnsm_a_SOURCES = $(GENFILES) file.c
+libnsm_a_SOURCES = $(GENFILES) file.c rpc.c
 
 BUILT_SOURCES = $(GENFILES)
 
diff --git a/support/nsm/rpc.c b/support/nsm/rpc.c
new file mode 100644
index 0000000..4e5f40e
--- /dev/null
+++ b/support/nsm/rpc.c
@@ -0,0 +1,534 @@
+/*
+ * Copyright 2009 Oracle.  All rights reserved.
+ *
+ * This file is part of nfs-utils.
+ *
+ * nfs-utils is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * nfs-utils is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with nfs-utils.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * NSM for Linux.
+ *
+ * Instead of using ONC or TI RPC library calls, statd constructs
+ * RPC calls directly in socket buffers.  This allows a single
+ * socket to be concurrently shared among several different RPC
+ * programs and versions using a simple RPC request dispatcher.
+ *
+ * This file contains the details of RPC header and call
+ * construction and reply parsing, and a method for creating a
+ * socket for use with these functions.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif	/* HAVE_CONFIG_H */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+
+#include <time.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include <netinet/in.h>
+#include <net/if.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+#include <rpc/rpc.h>
+#include <rpc/pmap_prot.h>
+#include <rpc/pmap_rmt.h>
+
+#ifdef HAVE_LIBTIRPC
+#include <netconfig.h>
+#include <rpc/rpcb_prot.h>
+#endif	/* HAVE_LIBTIRPC */
+
+#include "xlog.h"
+#include "nfsrpc.h"
+#include "nsm.h"
+#include "sm_inter.h"
+
+/*
+ * Returns a fresh XID appropriate for RPC over UDP -- never zero.
+ */
+static uint32_t
+nsm_next_xid(void)
+{
+	static uint32_t nsm_xid = 0;
+	struct timeval now;
+
+	if (nsm_xid == 0) {
+		(void)gettimeofday(&now, NULL);
+		nsm_xid = (uint32_t)getpid() ^
+				(uint32_t)now.tv_sec ^ (uint32_t)now.tv_usec;
+	}
+
+	return nsm_xid++;
+}
+
+/*
+ * Select a fresh XID and construct an RPC header in @mesg.
+ * Always use AUTH_NULL credentials and verifiers.
+ *
+ * Returns the new XID.
+ */
+static uint32_t
+nsm_init_rpc_header(const rpcprog_t program, const rpcvers_t version,
+			const rpcproc_t procedure, struct rpc_msg *mesg)
+{
+	struct call_body *cb = &mesg->rm_call;
+	uint32_t xid = nsm_next_xid();
+
+	memset(mesg, 0, sizeof(*mesg));
+
+	mesg->rm_xid = (unsigned long)xid;
+	mesg->rm_direction = CALL;
+
+	cb->cb_rpcvers = RPC_MSG_VERSION;
+	cb->cb_prog = program;
+	cb->cb_vers = version;
+	cb->cb_proc = procedure;
+
+	cb->cb_cred.oa_flavor = AUTH_NULL;
+	cb->cb_cred.oa_base = (caddr_t) NULL;
+	cb->cb_cred.oa_length = 0;
+	cb->cb_verf.oa_flavor = AUTH_NULL;
+	cb->cb_verf.oa_base = (caddr_t) NULL;
+	cb->cb_verf.oa_length = 0;
+
+	return xid;
+}
+
+/*
+ * Initialize the network send buffer and XDR memory for encoding.
+ */
+static void
+nsm_init_xdrmem(char *msgbuf, const unsigned int msgbuflen,
+		XDR *xdrp)
+{
+	memset(msgbuf, 0, (size_t)msgbuflen);
+	memset(xdrp, 0, sizeof(*xdrp));
+	xdrmem_create(xdrp, msgbuf, msgbuflen, XDR_ENCODE);
+}
+
+/*
+ * Send a completed RPC call on a socket.
+ *
+ * Returns true if all the bytes were sent successfully; otherwise
+ * false if any error occurred.
+ */
+static _Bool
+nsm_rpc_sendto(const int sock, const struct sockaddr *sap,
+			const socklen_t salen, XDR *xdrs, void *buf)
+{
+	const size_t buflen = (size_t)xdr_getpos(xdrs);
+	ssize_t err;
+
+	err = sendto(sock, buf, buflen, 0, sap, salen);
+	if ((err < 0) || ((size_t)err != buflen)) {
+		xlog(L_ERROR, "%s: sendto failed: %m", __func__);
+		return false;
+	}
+	return true;
+}
+
+/**
+ * nsm_xmit_getport - post a PMAP_GETPORT call on a socket descriptor
+ * @sock: datagram socket descriptor
+ * @sin: pointer to AF_INET socket address of server
+ * @program: RPC program number to query
+ * @version: RPC version number to query
+ *
+ * Send a PMAP_GETPORT call to the portmap daemon at @sin using
+ * socket descriptor @sock.  This request queries the RPC program
+ * [program, version, IPPROTO_UDP].
+ *
+ * NB: PMAP_GETPORT works only for IPv4 hosts.  This implementation
+ *     works only over UDP, and queries only UDP registrations.
+ *
+ * Returns the XID of the call, or zero if an error occurred.
+ */
+uint32_t
+nsm_xmit_getport(const int sock, const struct sockaddr_in *sin,
+			const unsigned long program,
+			const unsigned long version)
+{
+	char msgbuf[NSM_MAXMSGSIZE];
+	struct sockaddr_in addr;
+	struct rpc_msg mesg;
+	_Bool sent = false;
+	struct pmap parms = {
+		.pm_prog	= program,
+		.pm_vers	= version,
+		.pm_prot	= (unsigned long)IPPROTO_UDP,
+	};
+	uint32_t xid;
+	XDR xdr;
+
+	xlog(D_CALL, "Sending PMAP_GETPORT for %u, %u, udp", program, version);
+
+	nsm_init_xdrmem(msgbuf, NSM_MAXMSGSIZE, &xdr);
+	xid = nsm_init_rpc_header(PMAPPROG, PMAPVERS,
+					(rpcproc_t)PMAPPROC_GETPORT, &mesg);
+
+	addr = *sin;
+	addr.sin_port = htons(PMAPPORT);
+
+	if (xdr_callmsg(&xdr, &mesg) == TRUE &&
+	    xdr_pmap(&xdr, &parms) == TRUE)
+		sent = nsm_rpc_sendto(sock, (struct sockaddr *)(char *)&addr,
+					(socklen_t)sizeof(addr), &xdr, msgbuf);
+	else
+		xlog(L_ERROR, "%s: can't encode PMAP_GETPORT call", __func__);
+
+	xdr_destroy(&xdr);
+
+	if (sent == false)
+		return 0;
+	return xid;
+}
+
+/**
+ * nsm_xmit_getaddr - post an RPCB_GETADDR call on a socket descriptor
+ * @sock: datagram socket descriptor
+ * @sin: pointer to AF_INET6 socket address of server
+ * @program: RPC program number to query
+ * @version: RPC version number to query
+ *
+ * Send an RPCB_GETADDR call to the rpcbind daemon at @sap using
+ * socket descriptor @sock.  This request queries the RPC program
+ * [program, version, "udp6"].
+ *
+ * NB: RPCB_GETADDR works for both IPv4 and IPv6 hosts.  This
+ *     implementation works only over UDP and AF_INET6, and queries
+ *     only "udp6" registrations.
+ *
+ * Returns the XID of the call, or zero if an error occurred.
+ */
+#ifdef HAVE_LIBTIRPC
+uint32_t
+nsm_xmit_getaddr(const int sock, const struct sockaddr_in6 *sin6,
+			const rpcprog_t program, const rpcvers_t version)
+{
+	char msgbuf[NSM_MAXMSGSIZE];
+	struct sockaddr_in6 addr;
+	struct rpc_msg mesg;
+	_Bool sent = false;
+	struct rpcb parms = {
+		.r_prog		= program,
+		.r_vers		= version,
+		.r_netid	= "udp6",
+		.r_owner	= "",
+	};
+	uint32_t xid;
+	XDR xdr;
+
+	xlog(D_CALL, "Sending RPCB_GETADDR for %u, %u, udp6", program, version);
+
+	nsm_init_xdrmem(msgbuf, NSM_MAXMSGSIZE, &xdr);
+	xid = nsm_init_rpc_header(RPCBPROG, RPCBVERS,
+					(rpcproc_t)RPCBPROC_GETADDR, &mesg);
+
+	addr = *sin6;
+	addr.sin6_port = htons(PMAPPORT);
+	parms.r_addr = nfs_sockaddr2universal((struct sockaddr *)(char *)&addr);
+	if (parms.r_addr == NULL) {
+		xlog(L_ERROR, "%s: can't encode socket address", __func__);
+		return 0;
+	}
+
+	if (xdr_callmsg(&xdr, &mesg) == TRUE &&
+	    xdr_rpcb(&xdr, &parms) == TRUE)
+		sent = nsm_rpc_sendto(sock, (struct sockaddr *)(char *)&addr,
+					(socklen_t)sizeof(addr), &xdr, msgbuf);
+	else
+		xlog(L_ERROR, "%s: can't encode RPCB_GETADDR call", __func__);
+
+	xdr_destroy(&xdr);
+	free(parms.r_addr);
+
+	if (sent == false)
+		return 0;
+	return xid;
+}
+#else	/* !HAVE_LIBTIRPC */
+uint32_t
+nsm_xmit_getaddr(const int sock __attribute__((unused)),
+			const struct sockaddr_in6 *sin6 __attribute__((unused)),
+			const rpcprog_t program __attribute__((unused)),
+			const rpcvers_t version __attribute__((unused)))
+{
+	return 0;
+}
+#endif	/* !HAVE_LIBTIRPC */
+
+/**
+ * nsm_xmit_rpcbind - post an rpcbind request
+ * @sock: datagram socket descriptor
+ * @sap: pointer to socket address of server
+ * @program: RPC program number to query
+ * @version: RPC version number to query
+ *
+ * Send an rpcbind query to the rpcbind daemon at @sap using
+ * socket descriptor @sock.
+ *
+ * NB: This implementation works only over UDP, but can query IPv4 or IPv6
+ *     hosts.  It queries only UDP registrations.
+ *
+ * Returns the XID of the call, or zero if an error occurred.
+ */
+uint32_t
+nsm_xmit_rpcbind(const int sock, const struct sockaddr *sap,
+			const rpcprog_t program, const rpcvers_t version)
+{
+	switch (sap->sa_family) {
+	case AF_INET:
+		return nsm_xmit_getport(sock, (const struct sockaddr_in *)sap,
+						program, version);
+	case AF_INET6:
+		return nsm_xmit_getaddr(sock, (const struct sockaddr_in6 *)sap,
+						program, version);
+	}
+	return 0;
+}
+
+/**
+ * nsm_xmit_notify - post an NSMPROC_NOTIFY call on a socket descriptor
+ * @sock: datagram socket descriptor
+ * @sap: pointer to socket address of peer to notify (port already filled in)
+ * @salen: length of socket address
+ * @program: RPC program number to use
+ * @mon_name: mon_name of local peer (ie the rebooting system)
+ * @state: state of local peer
+ *
+ * Send an NSMPROC_NOTIFY call to the peer at @sap using socket descriptor @sock.
+ * This request notifies the peer that we have rebooted.
+ *
+ * NB: This implementation works only over UDP, but supports both AF_INET
+ *     and AF_INET6.
+ *
+ * Returns the XID of the call, or zero if an error occurred.
+ */
+uint32_t
+nsm_xmit_notify(const int sock, const struct sockaddr *sap,
+			const socklen_t salen, const rpcprog_t program,
+			const char *mon_name, const int state)
+{
+	char msgbuf[NSM_MAXMSGSIZE];
+	struct stat_chge state_change;
+	struct rpc_msg mesg;
+	_Bool sent = false;
+	uint32_t xid;
+	XDR xdr;
+
+	state_change.mon_name = strdup(mon_name);
+	if (state_change.mon_name == NULL) {
+		xlog(L_ERROR, "%s: no memory", __func__);
+		return 0;
+	}
+	state_change.state = state;
+
+	xlog(D_CALL, "Sending SM_NOTIFY for %s", mon_name);
+
+	nsm_init_xdrmem(msgbuf, NSM_MAXMSGSIZE, &xdr);
+	xid = nsm_init_rpc_header(program, SM_VERS, SM_NOTIFY, &mesg);
+
+	if (xdr_callmsg(&xdr, &mesg) == TRUE &&
+	    xdr_stat_chge(&xdr, &state_change) == TRUE)
+		sent = nsm_rpc_sendto(sock, sap, salen, &xdr, msgbuf);
+	else
+		xlog(L_ERROR, "%s: can't encode NSMPROC_NOTIFY call",
+				__func__);
+
+	xdr_destroy(&xdr);
+	free(state_change.mon_name);
+
+	if (sent == false)
+		return 0;
+	return xid;
+}
+
+/**
+ * nsm_xmit_nlmcall - post an unnamed call to local NLM on a socket descriptor
+ * @sock: datagram socket descriptor
+ * @sap: address/port of NLM service to contact
+ * @salen: size of @sap
+ * @m: callback data defining RPC call to make
+ * @state: state of rebooting host
+ *
+ * Send an unnamed call (previously requested via NSMPROC_MON) to the
+ * specified local UDP-based RPC service using socket descriptor @sock.
+ *
+ * NB: This implementation works only over UDP, but supports both AF_INET
+ *     and AF_INET6.
+ *
+ * Returns the XID of the call, or zero if an error occurred.
+ */
+uint32_t
+nsm_xmit_nlmcall(const int sock, const struct sockaddr *sap,
+			const socklen_t salen, const struct mon *m,
+			const int state)
+{
+	const struct my_id *id = &m->mon_id.my_id;
+	char msgbuf[NSM_MAXMSGSIZE];
+	struct status new_status;
+	struct rpc_msg mesg;
+	_Bool sent = false;
+	uint32_t xid;
+	XDR xdr;
+
+	xlog(D_CALL, "Sending NLM downcall for %s", m->mon_id.mon_name);
+
+	nsm_init_xdrmem(msgbuf, NSM_MAXMSGSIZE, &xdr);
+	xid = nsm_init_rpc_header((rpcprog_t)id->my_prog,
+					(rpcvers_t)id->my_vers,
+					(rpcproc_t)id->my_proc, &mesg);
+
+	new_status.mon_name = m->mon_id.mon_name;
+	new_status.state = state;
+	memcpy(&new_status.priv, &m->priv, sizeof(new_status.priv));
+
+	if (xdr_callmsg(&xdr, &mesg) == TRUE &&
+	    xdr_status(&xdr, &new_status) == TRUE)
+		sent = nsm_rpc_sendto(sock, sap, salen, &xdr, msgbuf);
+	else
+		xlog(L_ERROR, "%s: can't encode NLM downcall", __func__);
+
+	xdr_destroy(&xdr);
+
+	if (sent == false)
+		return 0;
+	return xid;
+}
+
+/**
+ * nsm_parse_reply - parse and validate the header in an RPC reply
+ * @xdrs: pointer to XDR
+ *
+ * Returns the XID of the reply, or zero if an error occurred.
+ */
+uint32_t
+nsm_parse_reply(XDR *xdrs)
+{
+	struct rpc_msg mesg = {
+		.rm_reply.rp_acpt.ar_results.proc	= (xdrproc_t)xdr_void,
+	};
+	uint32_t xid;
+
+	if (xdr_replymsg(xdrs, &mesg) == FALSE) {
+		xlog(L_ERROR, "%s: can't decode RPC reply", __func__);
+		return 0;
+	}
+	xid = (uint32_t)mesg.rm_xid;
+
+	if (mesg.rm_reply.rp_stat != MSG_ACCEPTED) {
+		xlog(L_ERROR, "%s: [0x%x] RPC status %d",
+			__func__, xid, mesg.rm_reply.rp_stat);
+		return 0;
+	}
+
+	if (mesg.rm_reply.rp_acpt.ar_stat != SUCCESS) {
+		xlog(L_ERROR, "%s: [0x%x] RPC accept status %d",
+			__func__, xid, mesg.rm_reply.rp_acpt.ar_stat);
+		return 0;
+	}
+
+	return xid;
+}
+
+/**
+ * nsm_recv_getport - parse PMAP_GETPORT reply
+ * @xdrs: pointer to XDR
+ *
+ * Returns the port number from the RPC reply, or zero
+ * if an error occurred.
+ */
+unsigned long
+nsm_recv_getport(XDR *xdrs)
+{
+	unsigned long port = 0;
+
+	if (xdr_u_long(xdrs, &port) == FALSE)
+		xlog(L_ERROR, "%s: can't decode pmap reply",
+			__func__);
+	if (port > UINT16_MAX) {
+		xlog(L_ERROR, "%s: bad port number",
+			__func__);
+		port = 0;
+	}
+
+	xlog(D_CALL, "Received PMAP_GETPORT result: %lu", port);
+	return port;
+}
+
+/**
+ * nsm_recv_getaddr - parse RPCB_GETADDR reply
+ * @xdrs: pointer to XDR
+ *
+ * Returns the port number from the RPC reply, or zero
+ * if an error occurred.
+ */
+uint16_t
+nsm_recv_getaddr(XDR *xdrs)
+{
+	char *uaddr = NULL;
+	int port;
+
+	if (xdr_wrapstring(xdrs, &uaddr) == FALSE)
+		xlog(L_ERROR, "%s: can't decode rpcb reply",
+			__func__);
+
+	if ((uaddr == NULL) || (uaddr[0] == '\0')) {
+		xlog(D_CALL, "Received RPCB_GETADDR result: "
+				"program not registered");
+		return 0;
+	}
+
+	port = nfs_universal2port(uaddr);
+
+	xdr_free((xdrproc_t)xdr_wrapstring, (char *)&uaddr);
+
+	if (port < 0 || port > UINT16_MAX) {
+		xlog(L_ERROR, "%s: bad port number",
+			__func__);
+		return 0;
+	}
+
+	xlog(D_CALL, "Received RPCB_GETADDR result: %d", port);
+	return (uint16_t)port;
+}
+
+/**
+ * nsm_recv_rpcbind - parse rpcbind reply
+ * @af: address family of reply
+ * @xdrs: pointer to XDR
+ *
+ * Returns the port number from the RPC reply, or zero
+ * if an error occurred.
+ */
+uint16_t
+nsm_recv_rpcbind(const sa_family_t family, XDR *xdrs)
+{
+	switch (family) {
+	case AF_INET:
+		return (uint16_t)nsm_recv_getport(xdrs);
+	case AF_INET6:
+		return nsm_recv_getaddr(xdrs);
+	}
+	return 0;
+}