net_mosq.c

/*
Copyright (c) 2009-2018 Roger Light <roger@atchoo.org>

All rights reserved. This program and the accompanying materials
are made available under the terms of the Eclipse Public License v1.0
and Eclipse Distribution License v1.0 which accompany this distribution.

The Eclipse Public License is available at
   http:https://www.eclipse.org/legal/epl-v10.html
and the Eclipse Distribution License is available at
  http:https://www.eclipse.org/org/documents/edl-v10.php.

Contributors:
   Roger Light - initial implementation and documentation.
*/

#define _GNU_SOURCE

#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#ifndef WIN32
#define _GNU_SOURCE
#include <netdb.h>
#include <sys/socket.h>
#include <unistd.h>
#else
#include <winsock2.h>
#include <ws2tcpip.h>
#endif

#ifdef __ANDROID__
#include <linux/in.h>
#include <linux/in6.h>
#include <sys/endian.h>
#endif

#ifdef HAVE_NETINET_IN_H
#  include <netinet/in.h>
#endif

#ifdef __QNX__
#include <net/netbyte.h>
#endif

#ifdef WITH_TLS
#include <openssl/conf.h>
#include <openssl/engine.h>
#include <openssl/err.h>
#include <tls_mosq.h>
#endif

#ifdef WITH_BROKER
#  include "mosquitto_broker_internal.h"
#  ifdef WITH_WEBSOCKETS
#    include <libwebsockets.h>
#  endif
#else
#  include "read_handle.h"
#endif

#include "logging_mosq.h"
#include "memory_mosq.h"
#include "mqtt3_protocol.h"
#include "net_mosq.h"
#include "time_mosq.h"
#include "util_mosq.h"

#include "config.h"

#ifdef WITH_TLS
int tls_ex_index_mosq = -1;
#endif

int net__init(void)
{
#ifdef WIN32
	WSADATA wsaData;
	if(WSAStartup(MAKEWORD(2,2), &wsaData) != 0){
		return MOSQ_ERR_UNKNOWN;
	}
#endif

#ifdef WITH_SRV
	ares_library_init(ARES_LIB_INIT_ALL);
#endif

#ifdef WITH_TLS
	SSL_load_error_strings();
	SSL_library_init();
	OpenSSL_add_all_algorithms();
	if(tls_ex_index_mosq == -1){
		tls_ex_index_mosq = SSL_get_ex_new_index(0, "client context", NULL, NULL, NULL);
	}
#endif
	return MOSQ_ERR_SUCCESS;
}

void net__cleanup(void)
{
#ifdef WITH_TLS
	#if OPENSSL_VERSION_NUMBER < 0x10100000L
		ERR_remove_state(0);
	#endif
	ENGINE_cleanup();
	CONF_modules_unload(1);
	ERR_free_strings();
	EVP_cleanup();
	CRYPTO_cleanup_all_ex_data();
#endif

#ifdef WITH_SRV
	ares_library_cleanup();
#endif

#ifdef WIN32
	WSACleanup();
#endif
}


/* Close a socket associated with a context and set it to -1.
 * Returns 1 on failure (context is NULL)
 * Returns 0 on success.
 */
#ifdef WITH_BROKER
int net__socket_close(struct mosquitto_db *db, struct mosquitto *mosq)
#else
int net__socket_close(struct mosquitto *mosq)
#endif
{
	int rc = 0;

	assert(mosq);
#ifdef WITH_TLS
#ifdef WITH_WEBSOCKETS
	if(!mosq->wsi)
#endif
	{
		if(mosq->ssl){
			SSL_shutdown(mosq->ssl);
			SSL_free(mosq->ssl);
			mosq->ssl = NULL;
		}
		if(mosq->ssl_ctx){
			SSL_CTX_free(mosq->ssl_ctx);
			mosq->ssl_ctx = NULL;
		}
	}
#endif

#ifdef WITH_WEBSOCKETS
	if(mosq->wsi)
	{
		if(mosq->state != mosq_cs_disconnecting){
			mosq->state = mosq_cs_disconnect_ws;
		}
		libwebsocket_callback_on_writable(mosq->ws_context, mosq->wsi);
	}else
#endif
	{
		if((int)mosq->sock >= 0){
#ifdef WITH_BROKER
			HASH_DELETE(hh_sock, db->contexts_by_sock, mosq);
#endif
			rc = COMPAT_CLOSE(mosq->sock);
			mosq->sock = INVALID_SOCKET;
		}
	}

#ifdef WITH_BROKER
	if(mosq->listener){
		mosq->listener->client_count--;
		assert(mosq->listener->client_count >= 0);
		mosq->listener = NULL;
	}
#endif

	return rc;
}


#ifdef WITH_TLS_PSK
static unsigned int psk_client_callback(SSL *ssl, const char *hint,
		char *identity, unsigned int max_identity_len,
		unsigned char *psk, unsigned int max_psk_len)
{
	struct mosquitto *mosq;
	int len;

	mosq = SSL_get_ex_data(ssl, tls_ex_index_mosq);
	if(!mosq) return 0;

	snprintf(identity, max_identity_len, "%s", mosq->tls_psk_identity);

	len = mosquitto__hex2bin(mosq->tls_psk, psk, max_psk_len);
	if (len < 0) return 0;
	return len;
}
#endif

#if defined(WITH_BROKER) && defined(__GLIBC__) && defined(WITH_ADNS)
/* Async connect, part 1 (dns lookup) */
int net__try_connect_step1(struct mosquitto *mosq, const char *host)
{
	int s;
	void *sevp = NULL;

	if(mosq->adns){
		mosquitto__free(mosq->adns);
	}
	mosq->adns = mosquitto__calloc(1, sizeof(struct gaicb));
	if(!mosq->adns){
		return MOSQ_ERR_NOMEM;
	}
	mosq->adns->ar_name = host;

	s = getaddrinfo_a(GAI_NOWAIT, &mosq->adns, 1, sevp);
	if(s){
		errno = s;
		mosquitto__free(mosq->adns);
		mosq->adns = NULL;
		return MOSQ_ERR_EAI;
	}

	return MOSQ_ERR_SUCCESS;
}

/* Async connect part 2, the connection. */
int net__try_connect_step2(struct mosquitto *mosq, uint16_t port, mosq_sock_t *sock)
{
	struct addrinfo *ainfo, *rp;
	int rc;

	ainfo = mosq->adns->ar_result;

	for(rp = ainfo; rp != NULL; rp = rp->ai_next){
		*sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
		if(*sock == INVALID_SOCKET) continue;

		if(rp->ai_family == AF_INET){
			((struct sockaddr_in *)rp->ai_addr)->sin_port = htons(port);
		}else if(rp->ai_family == AF_INET6){
			((struct sockaddr_in6 *)rp->ai_addr)->sin6_port = htons(port);
		}else{
			COMPAT_CLOSE(*sock);
			*sock = INVALID_SOCKET;
			continue;
		}

		/* Set non-blocking */
		if(net__socket_nonblock(sock)){
			continue;
		}

		rc = connect(*sock, rp->ai_addr, rp->ai_addrlen);
#ifdef WIN32
		errno = WSAGetLastError();
#endif
		if(rc == 0 || errno == EINPROGRESS || errno == COMPAT_EWOULDBLOCK){
			if(rc < 0 && (errno == EINPROGRESS || errno == COMPAT_EWOULDBLOCK)){
				rc = MOSQ_ERR_CONN_PENDING;
			}

			/* Set non-blocking */
			if(net__socket_nonblock(sock)){
				continue;
			}
			break;
		}

		COMPAT_CLOSE(*sock);
		*sock = INVALID_SOCKET;
	}
	freeaddrinfo(mosq->adns->ar_result);
	mosq->adns->ar_result = NULL;

	mosquitto__free(mosq->adns);
	mosq->adns = NULL;

	if(!rp){
		return MOSQ_ERR_ERRNO;
	}

	return rc;
}

#endif


int net__try_connect(struct mosquitto *mosq, const char *host, uint16_t port, mosq_sock_t *sock, const char *bind_address, bool blocking)
{
	struct addrinfo hints;
	struct addrinfo *ainfo, *rp;
	struct addrinfo *ainfo_bind, *rp_bind;
	int s;
	int rc = MOSQ_ERR_SUCCESS;
#ifdef WIN32
	uint32_t val = 1;
#endif

	*sock = INVALID_SOCKET;
	memset(&hints, 0, sizeof(struct addrinfo));
	hints.ai_family = AF_UNSPEC;
	hints.ai_socktype = SOCK_STREAM;

	s = getaddrinfo(host, NULL, &hints, &ainfo);
	if(s){
		errno = s;
		return MOSQ_ERR_EAI;
	}

	if(bind_address){
		s = getaddrinfo(bind_address, NULL, &hints, &ainfo_bind);
		if(s){
			freeaddrinfo(ainfo);
			errno = s;
			return MOSQ_ERR_EAI;
		}
	}

	for(rp = ainfo; rp != NULL; rp = rp->ai_next){
		*sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
		if(*sock == INVALID_SOCKET) continue;

		if(rp->ai_family == AF_INET){
			((struct sockaddr_in *)rp->ai_addr)->sin_port = htons(port);
		}else if(rp->ai_family == AF_INET6){
			((struct sockaddr_in6 *)rp->ai_addr)->sin6_port = htons(port);
		}else{
			COMPAT_CLOSE(*sock);
			*sock = INVALID_SOCKET;
			continue;
		}

		if(bind_address){
			for(rp_bind = ainfo_bind; rp_bind != NULL; rp_bind = rp_bind->ai_next){
				if(bind(*sock, rp_bind->ai_addr, rp_bind->ai_addrlen) == 0){
					break;
				}
			}
			if(!rp_bind){
				COMPAT_CLOSE(*sock);
				*sock = INVALID_SOCKET;
				continue;
			}
		}

		if(!blocking){
			/* Set non-blocking */
			if(net__socket_nonblock(sock)){
				continue;
			}
		}

		rc = connect(*sock, rp->ai_addr, rp->ai_addrlen);
#ifdef WIN32
		errno = WSAGetLastError();
#endif
		if(rc == 0 || errno == EINPROGRESS || errno == COMPAT_EWOULDBLOCK){
			if(rc < 0 && (errno == EINPROGRESS || errno == COMPAT_EWOULDBLOCK)){
				rc = MOSQ_ERR_CONN_PENDING;
			}

			if(blocking){
				/* Set non-blocking */
				if(net__socket_nonblock(sock)){
					continue;
				}
			}
			break;
		}

		COMPAT_CLOSE(*sock);
		*sock = INVALID_SOCKET;
	}
	freeaddrinfo(ainfo);
	if(bind_address){
		freeaddrinfo(ainfo_bind);
	}
	if(!rp){
		return MOSQ_ERR_ERRNO;
	}
	return rc;
}


#ifdef WITH_TLS
void net__print_ssl_error(struct mosquitto *mosq)
{
	char ebuf[256];
	unsigned long e;

	e = ERR_get_error();
	while(e){
		log__printf(mosq, MOSQ_LOG_ERR, "OpenSSL Error: %s", ERR_error_string(e, ebuf));
		e = ERR_get_error();
	}
}


int net__socket_connect_tls(struct mosquitto *mosq)
{
	int ret, err;

	ERR_clear_error();
	ret = SSL_connect(mosq->ssl);
	if(ret != 1) {
		err = SSL_get_error(mosq->ssl, ret);
		if (err == SSL_ERROR_SYSCALL) {
			mosq->want_connect = true;
			return MOSQ_ERR_SUCCESS;
		}
		if(err == SSL_ERROR_WANT_READ){
			mosq->want_connect = true;
			/* We always try to read anyway */
		}else if(err == SSL_ERROR_WANT_WRITE){
			mosq->want_write = true;
			mosq->want_connect = true;
		}else{
			net__print_ssl_error(mosq);

			COMPAT_CLOSE(mosq->sock);
			mosq->sock = INVALID_SOCKET;
			net__print_ssl_error(mosq);
			return MOSQ_ERR_TLS;
		}
	}else{
		mosq->want_connect = false;
	}
	return MOSQ_ERR_SUCCESS;
}
#endif


#ifdef WITH_TLS
static int net__init_ssl_ctx(struct mosquitto *mosq)
{
	int ret;

	if(mosq->ssl_ctx){
		if(!mosq->ssl_ctx_defaults){
			return MOSQ_ERR_SUCCESS;
		}else if(!mosq->tls_cafile && !mosq->tls_capath && !mosq->tls_psk){
			log__printf(mosq, MOSQ_LOG_ERR, "Error: MOSQ_OPT_SSL_CTX_WITH_DEFAULTS used without specifying cafile, capath or psk.");
			return MOSQ_ERR_INVAL;
		}
	}

	/* Apply default SSL_CTX settings. This is only used if MOSQ_OPT_SSL_CTX
	 * has not been set, or if both of MOSQ_OPT_SSL_CTX and
	 * MOSQ_OPT_SSL_CTX_WITH_DEFAULTS are set. */
	if(mosq->tls_cafile || mosq->tls_capath || mosq->tls_psk){
		if(!mosq->ssl_ctx){
#if OPENSSL_VERSION_NUMBER < 0x10100000L
			mosq->ssl_ctx = SSL_CTX_new(SSLv23_client_method());
#else
			mosq->ssl_ctx = SSL_CTX_new(TLS_client_method());
#endif

			if(!mosq->ssl_ctx){
				log__printf(mosq, MOSQ_LOG_ERR, "Error: Unable to create TLS context.");
				COMPAT_CLOSE(mosq->sock);
				mosq->sock = INVALID_SOCKET;
				net__print_ssl_error(mosq);
				return MOSQ_ERR_TLS;
			}
		}

		if(!mosq->tls_version){
			SSL_CTX_set_options(mosq->ssl_ctx, SSL_OP_NO_SSLv3);
		}else if(!strcmp(mosq->tls_version, "tlsv1.2")){
			SSL_CTX_set_options(mosq->ssl_ctx, SSL_OP_NO_SSLv3 | SSL_OP_NO_TLSv1_1 | SSL_OP_NO_TLSv1);
		}else if(!strcmp(mosq->tls_version, "tlsv1.1")){
			SSL_CTX_set_options(mosq->ssl_ctx, SSL_OP_NO_SSLv3 | SSL_OP_NO_TLSv1_2 | SSL_OP_NO_TLSv1);
		}else if(!strcmp(mosq->tls_version, "tlsv1")){
			SSL_CTX_set_options(mosq->ssl_ctx, SSL_OP_NO_SSLv3 | SSL_OP_NO_TLSv1_2 | SSL_OP_NO_TLSv1_1);
		}else{
			log__printf(mosq, MOSQ_LOG_ERR, "Error: Protocol %s not supported.", mosq->tls_version);
			COMPAT_CLOSE(mosq->sock);
			mosq->sock = INVALID_SOCKET;
			return MOSQ_ERR_INVAL;
		}

		/* Disable compression */
		SSL_CTX_set_options(mosq->ssl_ctx, SSL_OP_NO_COMPRESSION);

#ifdef SSL_MODE_RELEASE_BUFFERS
			/* Use even less memory per SSL connection. */
			SSL_CTX_set_mode(mosq->ssl_ctx, SSL_MODE_RELEASE_BUFFERS);
#endif

		if(mosq->tls_ciphers){
			ret = SSL_CTX_set_cipher_list(mosq->ssl_ctx, mosq->tls_ciphers);
			if(ret == 0){
				log__printf(mosq, MOSQ_LOG_ERR, "Error: Unable to set TLS ciphers. Check cipher list \"%s\".", mosq->tls_ciphers);
				COMPAT_CLOSE(mosq->sock);
				mosq->sock = INVALID_SOCKET;
				net__print_ssl_error(mosq);
				return MOSQ_ERR_TLS;
			}
		}
		if(mosq->tls_cafile || mosq->tls_capath){
			ret = SSL_CTX_load_verify_locations(mosq->ssl_ctx, mosq->tls_cafile, mosq->tls_capath);
			if(ret == 0){
#ifdef WITH_BROKER
				if(mosq->tls_cafile && mosq->tls_capath){
					log__printf(mosq, MOSQ_LOG_ERR, "Error: Unable to load CA certificates, check bridge_cafile \"%s\" and bridge_capath \"%s\".", mosq->tls_cafile, mosq->tls_capath);
				}else if(mosq->tls_cafile){
					log__printf(mosq, MOSQ_LOG_ERR, "Error: Unable to load CA certificates, check bridge_cafile \"%s\".", mosq->tls_cafile);
				}else{
					log__printf(mosq, MOSQ_LOG_ERR, "Error: Unable to load CA certificates, check bridge_capath \"%s\".", mosq->tls_capath);
				}
#else
				if(mosq->tls_cafile && mosq->tls_capath){
					log__printf(mosq, MOSQ_LOG_ERR, "Error: Unable to load CA certificates, check cafile \"%s\" and capath \"%s\".", mosq->tls_cafile, mosq->tls_capath);
				}else if(mosq->tls_cafile){
					log__printf(mosq, MOSQ_LOG_ERR, "Error: Unable to load CA certificates, check cafile \"%s\".", mosq->tls_cafile);
				}else{
					log__printf(mosq, MOSQ_LOG_ERR, "Error: Unable to load CA certificates, check capath \"%s\".", mosq->tls_capath);
				}
#endif
				COMPAT_CLOSE(mosq->sock);
				mosq->sock = INVALID_SOCKET;
				net__print_ssl_error(mosq);
				return MOSQ_ERR_TLS;
			}
			if(mosq->tls_cert_reqs == 0){
				SSL_CTX_set_verify(mosq->ssl_ctx, SSL_VERIFY_NONE, NULL);
			}else{
				SSL_CTX_set_verify(mosq->ssl_ctx, SSL_VERIFY_PEER, mosquitto__server_certificate_verify);
			}

			if(mosq->tls_pw_callback){
				SSL_CTX_set_default_passwd_cb(mosq->ssl_ctx, mosq->tls_pw_callback);
				SSL_CTX_set_default_passwd_cb_userdata(mosq->ssl_ctx, mosq);
			}

			if(mosq->tls_certfile){
				ret = SSL_CTX_use_certificate_chain_file(mosq->ssl_ctx, mosq->tls_certfile);
				if(ret != 1){
#ifdef WITH_BROKER
					log__printf(mosq, MOSQ_LOG_ERR, "Error: Unable to load client certificate, check bridge_certfile \"%s\".", mosq->tls_certfile);
#else
					log__printf(mosq, MOSQ_LOG_ERR, "Error: Unable to load client certificate \"%s\".", mosq->tls_certfile);
#endif
					COMPAT_CLOSE(mosq->sock);
					mosq->sock = INVALID_SOCKET;
					net__print_ssl_error(mosq);
					return MOSQ_ERR_TLS;
				}
			}
			if(mosq->tls_keyfile){
				ret = SSL_CTX_use_PrivateKey_file(mosq->ssl_ctx, mosq->tls_keyfile, SSL_FILETYPE_PEM);
				if(ret != 1){
#ifdef WITH_BROKER
					log__printf(mosq, MOSQ_LOG_ERR, "Error: Unable to load client key file, check bridge_keyfile \"%s\".", mosq->tls_keyfile);
#else
					log__printf(mosq, MOSQ_LOG_ERR, "Error: Unable to load client key file \"%s\".", mosq->tls_keyfile);
#endif
					COMPAT_CLOSE(mosq->sock);
					mosq->sock = INVALID_SOCKET;
					net__print_ssl_error(mosq);
					return MOSQ_ERR_TLS;
				}
				ret = SSL_CTX_check_private_key(mosq->ssl_ctx);
				if(ret != 1){
					log__printf(mosq, MOSQ_LOG_ERR, "Error: Client certificate/key are inconsistent.");
					COMPAT_CLOSE(mosq->sock);
					mosq->sock = INVALID_SOCKET;
					net__print_ssl_error(mosq);
					return MOSQ_ERR_TLS;
				}
			}
#ifdef WITH_TLS_PSK
		}else if(mosq->tls_psk){
			SSL_CTX_set_psk_client_callback(mosq->ssl_ctx, psk_client_callback);
#endif
		}
	}

	return MOSQ_ERR_SUCCESS;
}
#endif


int net__socket_connect_step3(struct mosquitto *mosq, const char *host, uint16_t port, const char *bind_address, bool blocking)
{
#ifdef WITH_TLS
	BIO *bio;

	int rc = net__init_ssl_ctx(mosq);
	if(rc) return rc;

	if(mosq->ssl_ctx){
		mosq->ssl = SSL_new(mosq->ssl_ctx);
		if(!mosq->ssl){
			COMPAT_CLOSE(mosq->sock);
			mosq->sock = INVALID_SOCKET;
			net__print_ssl_error(mosq);
			return MOSQ_ERR_TLS;
		}

		SSL_set_ex_data(mosq->ssl, tls_ex_index_mosq, mosq);
		bio = BIO_new_socket(mosq->sock, BIO_NOCLOSE);
		if(!bio){
			COMPAT_CLOSE(mosq->sock);
			mosq->sock = INVALID_SOCKET;
			net__print_ssl_error(mosq);
			return MOSQ_ERR_TLS;
		}
		SSL_set_bio(mosq->ssl, bio, bio);

		/*
		 * required for the SNI resolving
		 */
		if(SSL_set_tlsext_host_name(mosq->ssl, host) != 1) {
			COMPAT_CLOSE(mosq->sock);
			mosq->sock = INVALID_SOCKET;
			return MOSQ_ERR_TLS;
		}

		if(net__socket_connect_tls(mosq)){
			return MOSQ_ERR_TLS;
		}

	}
#endif
	return MOSQ_ERR_SUCCESS;
}

/* Create a socket and connect it to 'ip' on port 'port'.  */
int net__socket_connect(struct mosquitto *mosq, const char *host, uint16_t port, const char *bind_address, bool blocking)
{
	mosq_sock_t sock = INVALID_SOCKET;
	int rc;

	if(!mosq || !host || !port) return MOSQ_ERR_INVAL;

	rc = net__try_connect(mosq, host, port, &sock, bind_address, blocking);
	if(rc > 0) return rc;

	mosq->sock = sock;

	rc = net__socket_connect_step3(mosq, host, port, bind_address, blocking);
	if(rc) return rc;

	return MOSQ_ERR_SUCCESS;
}


ssize_t net__read(struct mosquitto *mosq, void *buf, size_t count)
{
#ifdef WITH_TLS
	int ret;
	int err;
#endif
	assert(mosq);
	errno = 0;
#ifdef WITH_TLS
	if(mosq->ssl){
		ERR_clear_error();
		ret = SSL_read(mosq->ssl, buf, count);
		if(ret <= 0){
			err = SSL_get_error(mosq->ssl, ret);
			if(err == SSL_ERROR_WANT_READ){
				ret = -1;
				errno = EAGAIN;
			}else if(err == SSL_ERROR_WANT_WRITE){
				ret = -1;
				mosq->want_write = true;
				errno = EAGAIN;
			}else{
				net__print_ssl_error(mosq);
				errno = EPROTO;
			}
#ifdef WIN32
			WSASetLastError(errno);
#endif
		}
		return (ssize_t )ret;
	}else{
		/* Call normal read/recv */

#endif

#ifndef WIN32
	return read(mosq->sock, buf, count);
#else
	return recv(mosq->sock, buf, count, 0);
#endif

#ifdef WITH_TLS
	}
#endif
}

ssize_t net__write(struct mosquitto *mosq, void *buf, size_t count)
{
#ifdef WITH_TLS
	int ret;
	int err;
#endif
	assert(mosq);

	errno = 0;
#ifdef WITH_TLS
	if(mosq->ssl){
		mosq->want_write = false;
		ERR_clear_error();
		ret = SSL_write(mosq->ssl, buf, count);
		if(ret < 0){
			err = SSL_get_error(mosq->ssl, ret);
			if(err == SSL_ERROR_WANT_READ){
				ret = -1;
				errno = EAGAIN;
			}else if(err == SSL_ERROR_WANT_WRITE){
				ret = -1;
				mosq->want_write = true;
				errno = EAGAIN;
			}else{
				net__print_ssl_error(mosq);
				errno = EPROTO;
			}
#ifdef WIN32
			WSASetLastError(errno);
#endif
		}
		return (ssize_t )ret;
	}else{
		/* Call normal write/send */
#endif

#ifndef WIN32
	return write(mosq->sock, buf, count);
#else
	return send(mosq->sock, buf, count, 0);
#endif

#ifdef WITH_TLS
	}
#endif
}


int net__socket_nonblock(mosq_sock_t *sock)
{
#ifndef WIN32
	int opt;
	/* Set non-blocking */
	opt = fcntl(*sock, F_GETFL, 0);
	if(opt == -1){
		COMPAT_CLOSE(*sock);
		*sock = INVALID_SOCKET;
		return MOSQ_ERR_ERRNO;
	}
	if(fcntl(*sock, F_SETFL, opt | O_NONBLOCK) == -1){
		/* If either fcntl fails, don't want to allow this client to connect. */
		COMPAT_CLOSE(*sock);
		return MOSQ_ERR_ERRNO;
	}
#else
	unsigned long opt = 1;
	if(ioctlsocket(*sock, FIONBIO, &opt)){
		COMPAT_CLOSE(*sock);
		return MOSQ_ERR_ERRNO;
	}
#endif
	return MOSQ_ERR_SUCCESS;
}


#ifndef WITH_BROKER
int net__socketpair(mosq_sock_t *pairR, mosq_sock_t *pairW)
{
#ifdef WIN32
	int family[2] = {AF_INET, AF_INET6};
	int i;
	struct sockaddr_storage ss;
	struct sockaddr_in *sa = (struct sockaddr_in *)&ss;
	struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)&ss;
	socklen_t ss_len;
	mosq_sock_t spR, spW;

	mosq_sock_t listensock;

	*pairR = INVALID_SOCKET;
	*pairW = INVALID_SOCKET;

	for(i=0; i<2; i++){
		memset(&ss, 0, sizeof(ss));
		if(family[i] == AF_INET){
			sa->sin_family = family[i];
			sa->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
			sa->sin_port = 0;
			ss_len = sizeof(struct sockaddr_in);
		}else if(family[i] == AF_INET6){
			sa6->sin6_family = family[i];
			sa6->sin6_addr = in6addr_loopback;
			sa6->sin6_port = 0;
			ss_len = sizeof(struct sockaddr_in6);
		}else{
			return MOSQ_ERR_INVAL;
		}

		listensock = socket(family[i], SOCK_STREAM, IPPROTO_TCP);
		if(listensock == -1){
			continue;
		}

		if(bind(listensock, (struct sockaddr *)&ss, ss_len) == -1){
			COMPAT_CLOSE(listensock);
			continue;
		}

		if(listen(listensock, 1) == -1){
			COMPAT_CLOSE(listensock);
			continue;
		}
		memset(&ss, 0, sizeof(ss));
		ss_len = sizeof(ss);
		if(getsockname(listensock, (struct sockaddr *)&ss, &ss_len) < 0){
			COMPAT_CLOSE(listensock);
			continue;
		}

		if(family[i] == AF_INET){
			sa->sin_family = family[i];
			sa->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
			ss_len = sizeof(struct sockaddr_in);
		}else if(family[i] == AF_INET6){
			sa6->sin6_family = family[i];
			sa6->sin6_addr = in6addr_loopback;
			ss_len = sizeof(struct sockaddr_in6);
		}

		spR = socket(family[i], SOCK_STREAM, IPPROTO_TCP);
		if(spR == -1){
			COMPAT_CLOSE(listensock);
			continue;
		}
		if(net__socket_nonblock(&spR)){
			COMPAT_CLOSE(listensock);
			continue;
		}
		if(connect(spR, (struct sockaddr *)&ss, ss_len) < 0){
#ifdef WIN32
			errno = WSAGetLastError();
#endif
			if(errno != EINPROGRESS && errno != COMPAT_EWOULDBLOCK){
				COMPAT_CLOSE(spR);
				COMPAT_CLOSE(listensock);
				continue;
			}
		}
		spW = accept(listensock, NULL, 0);
		if(spW == -1){
#ifdef WIN32
			errno = WSAGetLastError();
#endif
			if(errno != EINPROGRESS && errno != COMPAT_EWOULDBLOCK){
				COMPAT_CLOSE(spR);
				COMPAT_CLOSE(listensock);
				continue;
			}
		}

		if(net__socket_nonblock(&spW)){
			COMPAT_CLOSE(spR);
			COMPAT_CLOSE(listensock);
			continue;
		}
		COMPAT_CLOSE(listensock);

		*pairR = spR;
		*pairW = spW;
		return MOSQ_ERR_SUCCESS;
	}
	return MOSQ_ERR_UNKNOWN;
#else
	int sv[2];

	if(socketpair(AF_UNIX, SOCK_STREAM, 0, sv) == -1){
		return MOSQ_ERR_ERRNO;
	}
	if(net__socket_nonblock(&sv[0])){
		COMPAT_CLOSE(sv[1]);
		return MOSQ_ERR_ERRNO;
	}
	if(net__socket_nonblock(&sv[1])){
		COMPAT_CLOSE(sv[0]);
		return MOSQ_ERR_ERRNO;
	}
	*pairR = sv[0];
	*pairW = sv[1];
	return MOSQ_ERR_SUCCESS;
#endif
}
#endif