remote.c
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	/*
	* Copyright (c) 2008 Andrew Beekhof
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* This library 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
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	*
	*/
	#include <crm_internal.h>
	#include <crm/crm.h>

	#include <sys/param.h>
	#include <stdio.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <unistd.h>
	#include <sys/socket.h>
	#include <arpa/inet.h>
	#include <netinet/in.h>
	#include <netinet/ip.h>
	#include <netinet/tcp.h>
	#include <netdb.h>

	#include <stdlib.h>
	#include <errno.h>
	#include <glib.h>

	#include <bzlib.h>

	#include <crm/common/ipcs.h>
	#include <crm/common/xml.h>
	#include <crm/common/mainloop.h>
	#include <crm/common/remote_internal.h>

	#ifdef HAVE_GNUTLS_GNUTLS_H
	# undef KEYFILE
	# include <gnutls/gnutls.h>

	const int psk_tls_kx_order[] = {
	GNUTLS_KX_DHE_PSK,
	GNUTLS_KX_PSK,
	};

	const int anon_tls_kx_order[] = {
	GNUTLS_KX_ANON_DH,
	GNUTLS_KX_DHE_RSA,
	GNUTLS_KX_DHE_DSS,
	GNUTLS_KX_RSA,
	0
	};
	#endif

	/* Swab macros from linux/swab.h */
	#ifdef HAVE_LINUX_SWAB_H
	# include <linux/swab.h>
	#else
	/*
	* casts are necessary for constants, because we never know how for sure
	* how U/UL/ULL map to __u16, __u32, __u64. At least not in a portable way.
	*/
	#define __swab16(x) ((uint16_t)( \
	(((uint16_t)(x) & (uint16_t)0x00ffU) << 8) \| \
	(((uint16_t)(x) & (uint16_t)0xff00U) >> 8)))

	#define __swab32(x) ((uint32_t)( \
	(((uint32_t)(x) & (uint32_t)0x000000ffUL) << 24) \| \
	(((uint32_t)(x) & (uint32_t)0x0000ff00UL) << 8) \| \
	(((uint32_t)(x) & (uint32_t)0x00ff0000UL) >> 8) \| \
	(((uint32_t)(x) & (uint32_t)0xff000000UL) >> 24)))

	#define __swab64(x) ((uint64_t)( \
	(((uint64_t)(x) & (uint64_t)0x00000000000000ffULL) << 56) \| \
	(((uint64_t)(x) & (uint64_t)0x000000000000ff00ULL) << 40) \| \
	(((uint64_t)(x) & (uint64_t)0x0000000000ff0000ULL) << 24) \| \
	(((uint64_t)(x) & (uint64_t)0x00000000ff000000ULL) << 8) \| \
	(((uint64_t)(x) & (uint64_t)0x000000ff00000000ULL) >> 8) \| \
	(((uint64_t)(x) & (uint64_t)0x0000ff0000000000ULL) >> 24) \| \
	(((uint64_t)(x) & (uint64_t)0x00ff000000000000ULL) >> 40) \| \
	(((uint64_t)(x) & (uint64_t)0xff00000000000000ULL) >> 56)))
	#endif

	#define REMOTE_MSG_VERSION 1
	#define ENDIAN_LOCAL 0xBADADBBD

	struct crm_remote_header_v0
	{
	uint32_t endian; /* Detect messages from hosts with different endian-ness */
	uint32_t version;
	uint64_t id;
	uint64_t flags;
	uint32_t size_total;
	uint32_t payload_offset;
	uint32_t payload_compressed;
	uint32_t payload_uncompressed;

	/* New fields get added here */

	} __attribute__ ((packed));

	static struct crm_remote_header_v0 *
	crm_remote_header(crm_remote_t * remote)
	{
	struct crm_remote_header_v0 header = (struct crm_remote_header_v0 )remote->buffer;
	if(remote->buffer_offset < sizeof(struct crm_remote_header_v0)) {
	return NULL;

	} else if(header->endian != ENDIAN_LOCAL) {
	uint32_t endian = __swab32(header->endian);

	CRM_LOG_ASSERT(endian == ENDIAN_LOCAL);
	if(endian != ENDIAN_LOCAL) {
	crm_err("Invalid message detected, endian mismatch: %lx is neither %lx nor the swab'd %lx",
	ENDIAN_LOCAL, header->endian, endian);
	return NULL;
	}

	header->id = __swab64(header->id);
	header->flags = __swab64(header->flags);
	header->endian = __swab32(header->endian);

	header->version = __swab32(header->version);
	header->size_total = __swab32(header->size_total);
	header->payload_offset = __swab32(header->payload_offset);
	header->payload_compressed = __swab32(header->payload_compressed);
	header->payload_uncompressed = __swab32(header->payload_uncompressed);
	}

	return header;
	}

	#ifdef HAVE_GNUTLS_GNUTLS_H

	int
	crm_initiate_client_tls_handshake(crm_remote_t * remote, int timeout_ms)
	{
	int rc = 0;
	int pollrc = 0;
	time_t start = time(NULL);

	do {
	rc = gnutls_handshake(*remote->tls_session);
	if (rc == GNUTLS_E_INTERRUPTED \|\| rc == GNUTLS_E_AGAIN) {
	pollrc = crm_remote_ready(remote, 1000);
	if (pollrc < 0) {
	/* poll returned error, there is no hope */
	rc = -1;
	}
	}

	} while (((time(NULL) - start) < (timeout_ms / 1000)) &&
	(rc == GNUTLS_E_INTERRUPTED \|\| rc == GNUTLS_E_AGAIN));

	if (rc < 0) {
	crm_trace("gnutls_handshake() failed with %d", rc);
	}
	return rc;
	}

	/*!
	* \internal
	* \brief Set minimum prime size required by TLS client
	*
	* \param[in] session TLS session to affect
	*/
	static void
	pcmk__set_minimum_dh_bits(gnutls_session_t *session)
	{
	const char *dh_min_bits_s = getenv("PCMK_dh_min_bits");

	if (dh_min_bits_s) {
	int dh_min_bits = crm_parse_int(dh_min_bits_s, "0");

	/* This function is deprecated since GnuTLS 3.1.7, in favor of letting
	* the priority string imply the DH requirements, but this is the only
	* way to give the user control over compatibility with older servers.
	*/
	if (dh_min_bits > 0) {
	crm_info("Requiring server use a Diffie-Hellman prime of at least %d bits",
	dh_min_bits);
	gnutls_dh_set_prime_bits(*session, dh_min_bits);
	}
	}
	}

	static unsigned int
	pcmk__bound_dh_bits(unsigned int dh_bits)
	{
	const char *dh_min_bits_s = getenv("PCMK_dh_min_bits");
	const char *dh_max_bits_s = getenv("PCMK_dh_max_bits");
	int dh_min_bits = 0;
	int dh_max_bits = 0;

	if (dh_min_bits_s) {
	dh_min_bits = crm_parse_int(dh_min_bits_s, "0");
	}
	if (dh_max_bits_s) {
	dh_max_bits = crm_parse_int(dh_max_bits_s, "0");
	if ((dh_min_bits > 0) && (dh_max_bits > 0)
	&& (dh_max_bits < dh_min_bits)) {
	crm_warn("Ignoring PCMK_dh_max_bits because it is less than PCMK_dh_min_bits");
	dh_max_bits = 0;
	}
	}
	if ((dh_min_bits > 0) && (dh_bits < dh_min_bits)) {
	return dh_min_bits;
	}
	if ((dh_max_bits > 0) && (dh_bits > dh_max_bits)) {
	return dh_max_bits;
	}
	return dh_bits;
	}

	/*!
	* \internal
	* \brief Initialize a new TLS session
	*
	* \param[in] csock Connected socket for TLS session
	* \param[in] conn_type GNUTLS_SERVER or GNUTLS_CLIENT
	* \param[in] cred_type GNUTLS_CRD_ANON or GNUTLS_CRD_PSK
	* \param[in] credentials TLS session credentials
	*
	* \return Pointer to newly created session object, or NULL on error
	*/
	gnutls_session_t *
	pcmk__new_tls_session(int csock, unsigned int conn_type,
	gnutls_credentials_type_t cred_type, void *credentials)
	{
	int rc = GNUTLS_E_SUCCESS;
	# ifdef HAVE_GNUTLS_PRIORITY_SET_DIRECT
	const char *prio_base = NULL;
	char *prio = NULL;
	# endif
	gnutls_session_t *session = NULL;

	# ifdef HAVE_GNUTLS_PRIORITY_SET_DIRECT
	/* Determine list of acceptable ciphers, etc. Pacemaker always adds the
	* values required for its functionality.
	*
	* For an example of anonymous authentication, see:
	* http://www.manpagez.com/info/gnutls/gnutls-2.10.4/gnutls_81.php#Echo-Server-with-anonymous-authentication
	*/

	prio_base = getenv("PCMK_tls_priorities");
	if (prio_base == NULL) {
	prio_base = PCMK_GNUTLS_PRIORITIES;
	}
	prio = crm_strdup_printf("%s:%s", prio_base,
	(cred_type == GNUTLS_CRD_ANON)? "+ANON-DH" : "+DHE-PSK:+PSK");
	# endif

	session = gnutls_malloc(sizeof(gnutls_session_t));
	if (session == NULL) {
	rc = GNUTLS_E_MEMORY_ERROR;
	goto error;
	}

	rc = gnutls_init(session, conn_type);
	if (rc != GNUTLS_E_SUCCESS) {
	goto error;
	}

	# ifdef HAVE_GNUTLS_PRIORITY_SET_DIRECT
	/* @TODO On the server side, it would be more efficient to cache the
	* priority with gnutls_priority_init2() and set it with
	* gnutls_priority_set() for all sessions.
	*/
	rc = gnutls_priority_set_direct(*session, prio, NULL);
	if (rc != GNUTLS_E_SUCCESS) {
	goto error;
	}
	if (conn_type == GNUTLS_CLIENT) {
	pcmk__set_minimum_dh_bits(session);
	}
	# else
	gnutls_set_default_priority(*session);
	gnutls_kx_set_priority(*session, (cred_type == GNUTLS_CRD_ANON)? anon_tls_kx_order : psk_tls_kx_order);
	# endif

	gnutls_transport_set_ptr(*session,
	(gnutls_transport_ptr_t) GINT_TO_POINTER(csock));

	rc = gnutls_credentials_set(*session, cred_type, credentials);
	if (rc != GNUTLS_E_SUCCESS) {
	goto error;
	}
	# ifdef HAVE_GNUTLS_PRIORITY_SET_DIRECT
	free(prio);
	# endif
	return session;

	error:
	{
	# ifdef HAVE_GNUTLS_PRIORITY_SET_DIRECT
	const char *prio_s = prio;
	# else
	const char *prio_s = "default";
	# endif

	crm_err("Could not initialize %s TLS %s session: %s "
	CRM_XS " rc=%d priority='%s'",
	(cred_type == GNUTLS_CRD_ANON)? "anonymous" : "PSK",
	(conn_type == GNUTLS_SERVER)? "server" : "client",
	gnutls_strerror(rc), rc, prio_s);
	}
	# ifdef HAVE_GNUTLS_PRIORITY_SET_DIRECT
	free(prio);
	# endif
	if (session != NULL) {
	gnutls_free(session);
	}
	return NULL;
	}

	/*!
	* \internal
	* \brief Initialize Diffie-Hellman parameters for a TLS server
	*
	* \param[out] dh_params Parameter object to initialize
	*
	* \return GNUTLS_E_SUCCESS on success, GnuTLS error code on error
	* \todo The current best practice is to allow the client and server to
	* negotiate the Diffie-Hellman parameters via a TLS extension (RFC 7919).
	* However, we have to support both older versions of GnuTLS (<3.6) that
	* don't support the extension on our side, and older Pacemaker versions
	* that don't support the extension on the other side. The next best
	* practice would be to use a known good prime (see RFC 5114 section 2.2),
	* possibly stored in a file distributed with Pacemaker.
	*/
	int
	pcmk__init_tls_dh(gnutls_dh_params_t *dh_params)
	{
	int rc = GNUTLS_E_SUCCESS;
	unsigned int dh_bits = 0;

	rc = gnutls_dh_params_init(dh_params);
	if (rc != GNUTLS_E_SUCCESS) {
	goto error;
	}

	#ifdef HAVE_GNUTLS_SEC_PARAM_TO_PK_BITS
	dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH,
	GNUTLS_SEC_PARAM_NORMAL);
	if (dh_bits == 0) {
	rc = GNUTLS_E_DH_PRIME_UNACCEPTABLE;
	goto error;
	}
	#else
	dh_bits = 1024;
	#endif
	dh_bits = pcmk__bound_dh_bits(dh_bits);

	crm_info("Generating Diffie-Hellman parameters with %u-bit prime for TLS",
	dh_bits);
	rc = gnutls_dh_params_generate2(*dh_params, dh_bits);
	if (rc != GNUTLS_E_SUCCESS) {
	goto error;
	}

	return rc;

	error:
	crm_err("Could not initialize Diffie-Hellman parameters for TLS: %s "
	CRM_XS " rc=%d", gnutls_strerror(rc), rc);
	CRM_ASSERT(rc == GNUTLS_E_SUCCESS);
	return rc;
	}

	/*!
	* \internal
	* \brief Process handshake data from TLS client
	*
	* Read as much TLS handshake data as is available.
	*
	* \param[in] client Client connection
	*
	* \retval GnuTLS error code on error
	* \retval 0 if more data is needed
	* \retval 1 if handshake is successfully completed
	*/
	int
	pcmk__read_handshake_data(crm_client_t *client)
	{
	int rc = 0;

	CRM_ASSERT(client && client->remote && client->remote->tls_session);

	do {
	rc = gnutls_handshake(*client->remote->tls_session);
	} while (rc == GNUTLS_E_INTERRUPTED);

	if (rc == GNUTLS_E_AGAIN) {
	/* No more data is available at the moment. This function should be
	* invoked again once the client sends more.
	*/
	return 0;
	} else if (rc != GNUTLS_E_SUCCESS) {
	return rc;
	}
	return 1;
	}

	static int
	crm_send_tls(gnutls_session_t * session, const char *buf, size_t len)
	{
	const char *unsent = buf;
	int rc = 0;
	int total_send;

	if (buf == NULL) {
	return -EINVAL;
	}

	total_send = len;
	crm_trace("Message size: %llu", (unsigned long long) len);

	while (TRUE) {
	rc = gnutls_record_send(*session, unsent, len);

	if (rc == GNUTLS_E_INTERRUPTED \|\| rc == GNUTLS_E_AGAIN) {
	crm_trace("Retrying to send %llu bytes",
	(unsigned long long) len);

	} else if (rc < 0) {
	crm_err("Connection terminated: %s " CRM_XS " rc=%d",
	gnutls_strerror(rc), rc);
	rc = -ECONNABORTED;
	break;

	} else if (rc < len) {
	crm_debug("Sent %d of %llu bytes", rc, (unsigned long long) len);
	len -= rc;
	unsent += rc;
	} else {
	crm_trace("Sent all %d bytes", rc);
	break;
	}
	}

	return rc < 0 ? rc : total_send;
	}
	#endif

	static int
	crm_send_plaintext(int sock, const char *buf, size_t len)
	{

	int rc = 0;
	const char *unsent = buf;
	int total_send;

	if (buf == NULL) {
	return -EINVAL;
	}
	total_send = len;

	crm_trace("Message on socket %d: size=%llu",
	sock, (unsigned long long) len);
	retry:
	rc = write(sock, unsent, len);
	if (rc < 0) {
	rc = -errno;
	switch (errno) {
	case EINTR:
	case EAGAIN:
	crm_trace("Retry");
	goto retry;
	default:
	crm_perror(LOG_ERR, "Could only write %d of the remaining %d bytes", rc, (int)len);
	break;
	}

	} else if (rc < len) {
	crm_trace("Only sent %d of %llu remaining bytes",
	rc, (unsigned long long) len);
	len -= rc;
	unsent += rc;
	goto retry;

	} else {
	crm_trace("Sent %d bytes: %.100s", rc, buf);
	}

	return rc < 0 ? rc : total_send;

	}

	static int
	crm_remote_sendv(crm_remote_t * remote, struct iovec * iov, int iovs)
	{
	int lpc = 0;
	int rc = -ESOCKTNOSUPPORT;

	for(; lpc < iovs; lpc++) {

	#ifdef HAVE_GNUTLS_GNUTLS_H
	if (remote->tls_session) {
	rc = crm_send_tls(remote->tls_session, iov[lpc].iov_base, iov[lpc].iov_len);
	} else if (remote->tcp_socket) {
	#else
	if (remote->tcp_socket) {
	#endif
	rc = crm_send_plaintext(remote->tcp_socket, iov[lpc].iov_base, iov[lpc].iov_len);

	} else {
	crm_err("Unsupported connection type");
	}
	}
	return rc;
	}

	int
	crm_remote_send(crm_remote_t * remote, xmlNode * msg)
	{
	int rc = pcmk_ok;
	static uint64_t id = 0;
	char *xml_text = dump_xml_unformatted(msg);

	struct iovec iov[2];
	struct crm_remote_header_v0 *header;

	if (xml_text == NULL) {
	crm_err("Could not send remote message: no message provided");
	return -EINVAL;
	}

	header = calloc(1, sizeof(struct crm_remote_header_v0));
	iov[0].iov_base = header;
	iov[0].iov_len = sizeof(struct crm_remote_header_v0);

	iov[1].iov_base = xml_text;
	iov[1].iov_len = 1 + strlen(xml_text);

	id++;
	header->id = id;
	header->endian = ENDIAN_LOCAL;
	header->version = REMOTE_MSG_VERSION;
	header->payload_offset = iov[0].iov_len;
	header->payload_uncompressed = iov[1].iov_len;
	header->size_total = iov[0].iov_len + iov[1].iov_len;

	crm_trace("Sending len[0]=%d, start=%x",
	(int)iov[0].iov_len, (int)(void*)xml_text);
	rc = crm_remote_sendv(remote, iov, 2);
	if (rc < 0) {
	crm_err("Could not send remote message: %s " CRM_XS " rc=%d",
	pcmk_strerror(rc), rc);
	}

	free(iov[0].iov_base);
	free(iov[1].iov_base);
	return rc;
	}


	/*!
	* \internal
	* \brief handles the recv buffer and parsing out msgs.
	* \note new_data is owned by this function once it is passed in.
	*/
	xmlNode *
	crm_remote_parse_buffer(crm_remote_t * remote)
	{
	xmlNode *xml = NULL;
	struct crm_remote_header_v0 *header = crm_remote_header(remote);

	if (remote->buffer == NULL \|\| header == NULL) {
	return NULL;
	}

	/* Support compression on the receiving end now, in case we ever want to add it later */
	if (header->payload_compressed) {
	int rc = 0;
	unsigned int size_u = 1 + header->payload_uncompressed;
	char *uncompressed = calloc(1, header->payload_offset + size_u);

	crm_trace("Decompressing message data %d bytes into %d bytes",
	header->payload_compressed, size_u);

	rc = BZ2_bzBuffToBuffDecompress(uncompressed + header->payload_offset, &size_u,
	remote->buffer + header->payload_offset,
	header->payload_compressed, 1, 0);

	if (rc != BZ_OK && header->version > REMOTE_MSG_VERSION) {
	crm_warn("Couldn't decompress v%d message, we only understand v%d",
	header->version, REMOTE_MSG_VERSION);
	free(uncompressed);
	return NULL;

	} else if (rc != BZ_OK) {
	crm_err("Decompression failed: %s (%d)", bz2_strerror(rc), rc);
	free(uncompressed);
	return NULL;
	}

	CRM_ASSERT(size_u == header->payload_uncompressed);

	memcpy(uncompressed, remote->buffer, header->payload_offset); /* Preserve the header */
	remote->buffer_size = header->payload_offset + size_u;

	free(remote->buffer);
	remote->buffer = uncompressed;
	header = crm_remote_header(remote);
	}

	/* take ownership of the buffer */
	remote->buffer_offset = 0;

	CRM_LOG_ASSERT(remote->buffer[sizeof(struct crm_remote_header_v0) + header->payload_uncompressed - 1] == 0);

	xml = string2xml(remote->buffer + header->payload_offset);
	if (xml == NULL && header->version > REMOTE_MSG_VERSION) {
	crm_warn("Couldn't parse v%d message, we only understand v%d",
	header->version, REMOTE_MSG_VERSION);

	} else if (xml == NULL) {
	crm_err("Couldn't parse: '%.120s'", remote->buffer + header->payload_offset);
	}

	return xml;
	}

	/*!
	* \internal
	* \brief Wait for a remote session to have data to read
	*
	* \param[in] remote Connection to check
	* \param[in] total_timeout Maximum time (in ms) to wait
	*
	* \return Positive value if ready to be read, 0 on timeout, -errno on error
	*/
	int
	crm_remote_ready(crm_remote_t *remote, int total_timeout)
	{
	struct pollfd fds = { 0, };
	int sock = 0;
	int rc = 0;
	time_t start;
	int timeout = total_timeout;

	#ifdef HAVE_GNUTLS_GNUTLS_H
	if (remote->tls_session) {
	void sock_ptr = gnutls_transport_get_ptr(remote->tls_session);

	sock = GPOINTER_TO_INT(sock_ptr);
	} else if (remote->tcp_socket) {
	#else
	if (remote->tcp_socket) {
	#endif
	sock = remote->tcp_socket;
	} else {
	crm_err("Unsupported connection type");
	}

	if (sock <= 0) {
	crm_trace("No longer connected");
	return -ENOTCONN;
	}

	start = time(NULL);
	errno = 0;
	do {
	fds.fd = sock;
	fds.events = POLLIN;

	/* If we got an EINTR while polling, and we have a
	* specific timeout we are trying to honor, attempt
	* to adjust the timeout to the closest second. */
	if (errno == EINTR && (timeout > 0)) {
	timeout = total_timeout - ((time(NULL) - start) * 1000);
	if (timeout < 1000) {
	timeout = 1000;
	}
	}

	rc = poll(&fds, 1, timeout);
	} while (rc < 0 && errno == EINTR);

	return (rc < 0)? -errno : rc;
	}


	/*!
	* \internal
	* \brief Read bytes off non blocking remote connection.
	*
	* \note only use with NON-Blocking sockets. Should only be used after polling socket.
	* This function will return once max_size is met, the socket read buffer
	* is empty, or an error is encountered.
	*
	* \retval number of bytes received
	*/
	static size_t
	crm_remote_recv_once(crm_remote_t * remote)
	{
	int rc = 0;
	size_t read_len = sizeof(struct crm_remote_header_v0);
	struct crm_remote_header_v0 *header = crm_remote_header(remote);

	if(header) {
	/* Stop at the end of the current message */
	read_len = header->size_total;
	}

	/* automatically grow the buffer when needed */
	if(remote->buffer_size < read_len) {
	remote->buffer_size = 2 * read_len;
	crm_trace("Expanding buffer to %llu bytes",
	(unsigned long long) remote->buffer_size);

	remote->buffer = realloc_safe(remote->buffer, remote->buffer_size + 1);
	CRM_ASSERT(remote->buffer != NULL);
	}

	#ifdef HAVE_GNUTLS_GNUTLS_H
	if (remote->tls_session) {
	rc = gnutls_record_recv(*(remote->tls_session),
	remote->buffer + remote->buffer_offset,
	remote->buffer_size - remote->buffer_offset);
	if (rc == GNUTLS_E_INTERRUPTED) {
	rc = -EINTR;
	} else if (rc == GNUTLS_E_AGAIN) {
	rc = -EAGAIN;
	} else if (rc < 0) {
	crm_debug("TLS receive failed: %s (%d)", gnutls_strerror(rc), rc);
	rc = -pcmk_err_generic;
	}
	} else if (remote->tcp_socket) {
	#else
	if (remote->tcp_socket) {
	#endif
	errno = 0;
	rc = read(remote->tcp_socket,
	remote->buffer + remote->buffer_offset,
	remote->buffer_size - remote->buffer_offset);
	if(rc < 0) {
	rc = -errno;
	}

	} else {
	crm_err("Unsupported connection type");
	return -ESOCKTNOSUPPORT;
	}

	/* process any errors. */
	if (rc > 0) {
	remote->buffer_offset += rc;
	/* always null terminate buffer, the +1 to alloc always allows for this. */
	remote->buffer[remote->buffer_offset] = '\0';
	crm_trace("Received %u more bytes, %llu total",
	rc, (unsigned long long) remote->buffer_offset);

	} else if (rc == -EINTR \|\| rc == -EAGAIN) {
	crm_trace("non-blocking, exiting read: %s (%d)", pcmk_strerror(rc), rc);

	} else if (rc == 0) {
	crm_debug("EOF encoutered after %llu bytes",
	(unsigned long long) remote->buffer_offset);
	return -ENOTCONN;

	} else {
	crm_debug("Error receiving message after %llu bytes: %s (%d)",
	(unsigned long long) remote->buffer_offset,
	pcmk_strerror(rc), rc);
	return -ENOTCONN;
	}

	header = crm_remote_header(remote);
	if(header) {
	if(remote->buffer_offset < header->size_total) {
	crm_trace("Read less than the advertised length: %llu < %u bytes",
	(unsigned long long) remote->buffer_offset,
	header->size_total);
	} else {
	crm_trace("Read full message of %llu bytes",
	(unsigned long long) remote->buffer_offset);
	return remote->buffer_offset;
	}
	}

	return -EAGAIN;
	}

	/*!
	* \internal
	* \brief Read message(s) from a remote connection
	*
	* \param[in] remote Remote connection to read
	* \param[in] total_timeout Fail if message not read in this time (ms)
	* \param[out] disconnected Will be set to 1 if disconnect detected
	*
	* \return TRUE if at least one full message read, FALSE otherwise
	*/
	gboolean
	crm_remote_recv(crm_remote_t remote, int total_timeout, int disconnected)
	{
	int rc;
	time_t start = time(NULL);
	int remaining_timeout = 0;

	if (total_timeout == 0) {
	total_timeout = 10000;
	} else if (total_timeout < 0) {
	total_timeout = 60000;
	}
	*disconnected = 0;

	remaining_timeout = total_timeout;
	while ((remaining_timeout > 0) && !(*disconnected)) {

	crm_trace("Waiting for remote data (%d of %d ms timeout remaining)",
	remaining_timeout, total_timeout);
	rc = crm_remote_ready(remote, remaining_timeout);

	if (rc == 0) {
	crm_err("Timed out (%d ms) while waiting for remote data",
	remaining_timeout);
	return FALSE;

	} else if (rc < 0) {
	crm_debug("Wait for remote data aborted, will try again: %s "
	CRM_XS " rc=%d", pcmk_strerror(rc), rc);

	} else {
	rc = crm_remote_recv_once(remote);
	if (rc > 0) {
	return TRUE;
	} else if (rc == -EAGAIN) {
	crm_trace("Still waiting for remote data");
	} else if (rc < 0) {
	crm_debug("Could not receive remote data: %s " CRM_XS " rc=%d",
	pcmk_strerror(rc), rc);
	}
	}

	if (rc == -ENOTCONN) {
	*disconnected = 1;
	return FALSE;
	}

	remaining_timeout = total_timeout - ((time(NULL) - start) * 1000);
	}

	return FALSE;
	}

	struct tcp_async_cb_data {
	gboolean success;
	int sock;
	void *userdata;
	void (callback) (void userdata, int sock);
	int timeout; /ms /
	time_t start;
	};

	static gboolean
	check_connect_finished(gpointer userdata)
	{
	struct tcp_async_cb_data *cb_data = userdata;
	int cb_arg = 0; // socket fd on success, -errno on error
	int sock = cb_data->sock;
	int error = 0;

	fd_set rset, wset;
	socklen_t len = sizeof(error);
	struct timeval ts = { 0, };

	if (cb_data->success == TRUE) {
	goto dispatch_done;
	}

	FD_ZERO(&rset);
	FD_SET(sock, &rset);
	wset = rset;

	crm_trace("fd %d: checking to see if connect finished", sock);
	cb_arg = select(sock + 1, &rset, &wset, NULL, &ts);

	if (cb_arg < 0) {
	cb_arg = -errno;
	if ((errno == EINPROGRESS) \|\| (errno == EAGAIN)) {
	/* reschedule if there is still time left */
	if ((time(NULL) - cb_data->start) < (cb_data->timeout / 1000)) {
	goto reschedule;
	} else {
	cb_arg = -ETIMEDOUT;
	}
	}
	crm_trace("fd %d: select failed %d connect dispatch ", sock, cb_arg);
	goto dispatch_done;
	} else if (cb_arg == 0) {
	if ((time(NULL) - cb_data->start) < (cb_data->timeout / 1000)) {
	goto reschedule;
	}
	crm_debug("fd %d: timeout during select", sock);
	cb_arg = -ETIMEDOUT;
	goto dispatch_done;
	} else {
	crm_trace("fd %d: select returned success", sock);
	cb_arg = 0;
	}

	/* can we read or write to the socket now? */
	if (FD_ISSET(sock, &rset) \|\| FD_ISSET(sock, &wset)) {
	if (getsockopt(sock, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
	cb_arg = -errno;
	crm_trace("fd %d: call to getsockopt failed", sock);
	goto dispatch_done;
	}
	if (error) {
	crm_trace("fd %d: error returned from getsockopt: %d", sock, error);
	cb_arg = -error;
	goto dispatch_done;
	}
	} else {
	crm_trace("neither read nor write set after select");
	cb_arg = -EAGAIN;
	goto dispatch_done;
	}

	dispatch_done:
	if (!cb_arg) {
	crm_trace("fd %d: connected", sock);
	/* Success, set the return code to the sock to report to the callback */
	cb_arg = cb_data->sock;
	cb_data->sock = 0;
	} else {
	close(sock);
	}

	if (cb_data->callback) {
	cb_data->callback(cb_data->userdata, cb_arg);
	}
	free(cb_data);
	return FALSE;

	reschedule:

	/* will check again next interval */
	return TRUE;
	}

	static int
	internal_tcp_connect_async(int sock,
	const struct sockaddr addr, socklen_t addrlen, int timeout / ms */ ,
	int timer_id, void userdata, void (callback) (void userdata, int sock))
	{
	int rc = 0;
	int interval = 500;
	int timer;
	struct tcp_async_cb_data *cb_data = NULL;

	rc = crm_set_nonblocking(sock);
	if (rc < 0) {
	crm_warn("Could not set socket non-blocking: %s " CRM_XS " rc=%d",
	pcmk_strerror(rc), rc);
	close(sock);
	return -1;
	}

	rc = connect(sock, addr, addrlen);
	if (rc < 0 && (errno != EINPROGRESS) && (errno != EAGAIN)) {
	crm_perror(LOG_WARNING, "connect");
	return -1;
	}

	cb_data = calloc(1, sizeof(struct tcp_async_cb_data));
	cb_data->userdata = userdata;
	cb_data->callback = callback;
	cb_data->sock = sock;
	cb_data->timeout = timeout;
	cb_data->start = time(NULL);

	if (rc == 0) {
	/* The connect was successful immediately, we still return to mainloop
	* and let this callback get called later. This avoids the user of this api
	* to have to account for the fact the callback could be invoked within this
	* function before returning. */
	cb_data->success = TRUE;
	interval = 1;
	}

	/* Check connect finished is mostly doing a non-block poll on the socket
	* to see if we can read/write to it. Once we can, the connect has completed.
	* This method allows us to connect to the server without blocking mainloop.
	*
	* This is a poor man's way of polling to see when the connection finished.
	* At some point we should figure out a way to use a mainloop fd callback for this.
	* Something about the way mainloop is currently polling prevents this from working at the
	* moment though. */
	crm_trace("Scheduling check in %dms for whether connect to fd %d finished",
	interval, sock);
	timer = g_timeout_add(interval, check_connect_finished, cb_data);
	if (timer_id) {
	*timer_id = timer;
	}

	return 0;
	}

	static int
	internal_tcp_connect(int sock, const struct sockaddr *addr, socklen_t addrlen)
	{
	int rc = connect(sock, addr, addrlen);

	if (rc < 0) {
	rc = -errno;
	crm_warn("Could not connect socket: %s " CRM_XS " rc=%d",
	pcmk_strerror(rc), rc);
	return rc;
	}

	rc = crm_set_nonblocking(sock);
	if (rc < 0) {
	crm_warn("Could not set socket non-blocking: %s " CRM_XS " rc=%d",
	pcmk_strerror(rc), rc);
	return rc;
	}

	return pcmk_ok;
	}

	/*!
	* \internal
	* \brief Connect to server at specified TCP port
	*
	* \param[in] host Name of server to connect to
	* \param[in] port Server port to connect to
	* \param[in] timeout Report error if not connected in this many milliseconds
	* \param[out] timer_id If non-NULL, will be set to timer ID, if asynchronous
	* \param[in] userdata Data to pass to callback, if asynchronous
	* \param[in] callback If non-NULL, connect asynchronously then call this
	*
	* \return File descriptor of connected socket on success, -ENOTCONN otherwise
	*/
	int
	crm_remote_tcp_connect_async(const char *host, int port, int timeout,
	int timer_id, void userdata,
	void (callback) (void userdata, int sock))
	{
	char buffer[INET6_ADDRSTRLEN];
	struct addrinfo *res = NULL;
	struct addrinfo *rp = NULL;
	struct addrinfo hints;
	const char *server = host;
	int ret_ga;
	int sock = -ENOTCONN;

	// Get host's IP address(es)
	memset(&hints, 0, sizeof(struct addrinfo));
	hints.ai_family = AF_UNSPEC; /* Allow IPv4 or IPv6 */
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_flags = AI_CANONNAME;
	ret_ga = getaddrinfo(server, NULL, &hints, &res);
	if (ret_ga) {
	crm_err("Unable to get IP address info for %s: %s",
	server, gai_strerror(ret_ga));
	goto async_cleanup;
	}
	if (!res \|\| !res->ai_addr) {
	crm_err("Unable to get IP address info for %s: no result", server);
	goto async_cleanup;
	}

	// getaddrinfo() returns a list of host's addresses, try them in order
	for (rp = res; rp != NULL; rp = rp->ai_next) {
	struct sockaddr *addr = rp->ai_addr;

	if (!addr) {
	continue;
	}

	if (rp->ai_canonname) {
	server = res->ai_canonname;
	}
	crm_debug("Got canonical name %s for %s", server, host);

	sock = socket(rp->ai_family, SOCK_STREAM, IPPROTO_TCP);
	if (sock == -1) {
	crm_perror(LOG_WARNING, "creating socket for connection to %s",
	server);
	sock = -ENOTCONN;
	continue;
	}

	/* Set port appropriately for address family */
	/* (void) casts avoid false-positive compiler alignment warnings /
	if (addr->sa_family == AF_INET6) {
	((struct sockaddr_in6 )(void)addr)->sin6_port = htons(port);
	} else {
	((struct sockaddr_in )(void)addr)->sin_port = htons(port);
	}

	memset(buffer, 0, DIMOF(buffer));
	crm_sockaddr2str(addr, buffer);
	crm_info("Attempting TCP connection to %s:%d", buffer, port);

	if (callback) {
	if (internal_tcp_connect_async
	(sock, rp->ai_addr, rp->ai_addrlen, timeout, timer_id, userdata, callback) == 0) {
	goto async_cleanup; /* Success for now, we'll hear back later in the callback */
	}

	} else if (internal_tcp_connect(sock, rp->ai_addr, rp->ai_addrlen) == 0) {
	break; /* Success */
	}

	close(sock);
	sock = -ENOTCONN;
	}

	async_cleanup:

	if (res) {
	freeaddrinfo(res);
	}
	return sock;
	}

	int
	crm_remote_tcp_connect(const char *host, int port)
	{
	return crm_remote_tcp_connect_async(host, port, -1, NULL, NULL, NULL);
	}

	/*!
	* \brief Convert an IP address (IPv4 or IPv6) to a string for logging
	*
	* \param[in] sa Socket address for IP
	* \param[out] s Storage for at least INET6_ADDRSTRLEN bytes
	*
	* \note sa The socket address can be a pointer to struct sockaddr_in (IPv4),
	* struct sockaddr_in6 (IPv6) or struct sockaddr_storage (either),
	* as long as its sa_family member is set correctly.
	*/
	void
	crm_sockaddr2str(void sa, char s)
	{
	switch (((struct sockaddr*)sa)->sa_family) {
	case AF_INET:
	inet_ntop(AF_INET, &(((struct sockaddr_in *)sa)->sin_addr),
	s, INET6_ADDRSTRLEN);
	break;

	case AF_INET6:
	inet_ntop(AF_INET6, &(((struct sockaddr_in6 *)sa)->sin6_addr),
	s, INET6_ADDRSTRLEN);
	break;

	default:
	strcpy(s, "<invalid>");
	}
	}

	int
	crm_remote_accept(int ssock)
	{
	int csock = 0;
	int rc = 0;
	unsigned laddr = 0;
	struct sockaddr_storage addr;
	char addr_str[INET6_ADDRSTRLEN];
	#ifdef TCP_USER_TIMEOUT
	int optval;
	long sbd_timeout = crm_get_sbd_timeout();
	#endif

	/* accept the connection */
	laddr = sizeof(addr);
	memset(&addr, 0, sizeof(addr));
	csock = accept(ssock, (struct sockaddr *)&addr, &laddr);
	crm_sockaddr2str(&addr, addr_str);
	crm_info("New remote connection from %s", addr_str);

	if (csock == -1) {
	crm_err("accept socket failed");
	return -1;
	}

	rc = crm_set_nonblocking(csock);
	if (rc < 0) {
	crm_err("Could not set socket non-blocking: %s " CRM_XS " rc=%d",
	pcmk_strerror(rc), rc);
	close(csock);
	return rc;
	}

	#ifdef TCP_USER_TIMEOUT
	if (sbd_timeout > 0) {
	optval = sbd_timeout / 2; /* time to fail and retry before watchdog */
	rc = setsockopt(csock, SOL_TCP, TCP_USER_TIMEOUT,
	&optval, sizeof(optval));
	if (rc < 0) {
	crm_err("setting TCP_USER_TIMEOUT (%d) on client socket failed",
	optval);
	close(csock);
	return rc;
	}
	}
	#endif

	return csock;
	}

	/*!
	* \brief Get the default remote connection TCP port on this host
	*
	* \return Remote connection TCP port number
	*/
	int
	crm_default_remote_port()
	{
	static int port = 0;

	if (port == 0) {
	const char *env = getenv("PCMK_remote_port");

	if (env) {
	errno = 0;
	port = strtol(env, NULL, 10);
	if (errno \|\| (port < 1) \|\| (port > 65535)) {
	crm_warn("Environment variable PCMK_remote_port has invalid value '%s', using %d instead",
	env, DEFAULT_REMOTE_PORT);
	port = DEFAULT_REMOTE_PORT;
	}
	} else {
	port = DEFAULT_REMOTE_PORT;
	}
	}
	return port;
	}

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