Add support for unix sockets to broker, lib, and clients.

CMakeLists.txt

@@ -43,6 +43,12 @@ else (WITH_TLS)
  set (OPENSSL_INCLUDE_DIR "")
 endif (WITH_TLS)
 
+
+option(WITH_UNIX_SOCKETS "Include Unix Domain Socket support?" ON)
+if (WITH_UNIX_SOCKETS AND NOT WIN32)
+ add_definitions("-DWITH_UNIX_SOCKETS")
+endif (WITH_UNIX_SOCKETS AND NOT WIN32)
+
 option(WITH_SOCKS "Include SOCKS5 support?" ON)
 if (WITH_SOCKS)
  add_definitions("-DWITH_SOCKS")

ChangeLog.txt

@@ -2,15 +2,19 @@ Broker:
 - When running as root, if dropping privileges to the "mosquitto" user fails,
  then try "nobody" instead. This reduces the burden on users installing
  Mosquitto themselves.
+- Add support for Unix domain socket listeners.
 
 Client library:
 - Client no longer generates random client ids for v3.1.1 clients, these are
  now expected to be generated on the broker. This matches the behaviour for
  v5 clients. Closes #291.
+- Add support for connecting to brokers through Unix domain sockets.
 
 Clients:
 - Add timeout return code (27) for `mosquitto_sub -W <secs>` and
  `mosquitto_rr -W <secs>`. Closes #275.
+- Add support for connecting to brokers through Unix domain sockets with the
+ `--unix` argument.
 
 
 1.6.7 - 20190925

buildtest.py

@@ -18,6 +18,7 @@
  'WITH_THREADING',
  'WITH_TLS',
  'WITH_TLS_PSK',
+ 'WITH_UNIX_SOCKETS',
  'WITH_WEBSOCKETS',
  'WITH_WRAP',
 ]

client/client_shared.c

@@ -125,7 +125,7 @@ static int check_format(const char *str)
 void init_config(struct mosq_config *cfg, int pub_or_sub)
 {
  memset(cfg, 0, sizeof(*cfg));
- cfg->port = -1;
+ cfg->port = PORT_UNDEFINED;
  cfg->max_inflight = 20;
  cfg->keepalive = 60;
  cfg->clean_session = true;
@@ -742,7 +742,7 @@ int client_config_line_proc(struct mosq_config *cfg, int pub_or_sub, int argc, c
  return 1;
  }else{
  cfg->port = atoi(argv[i+1]);
- if(cfg->port<1 || cfg->port>65535){
+ if(cfg->port<0 || cfg->port>65535){
  fprintf(stderr, "Error: Invalid port given: %d\n", cfg->port);
  return 1;
  }
@@ -974,6 +974,15 @@ int client_config_line_proc(struct mosq_config *cfg, int pub_or_sub, int argc, c
  cfg->username = strdup(argv[i+1]);
  }
  i++;
+ }else if(!strcmp(argv[i], "--unix")){
+ if(i==argc-1){
+ fprintf(stderr, "Error: --unix argument given but no socket path specified.\n\n");
+ return 1;
+ }else{
+ cfg->host = strdup(argv[i+1]);
+ cfg->port = 0;
+ }
+ i++;
  }else if(!strcmp(argv[i], "-V") || !strcmp(argv[i], "--protocol-version")){
  if(i==argc-1){
  fprintf(stderr, "Error: --protocol-version argument given but no version specified.\n\n");
@@ -1174,7 +1183,7 @@ int client_connect(struct mosquitto *mosq, struct mosq_config *cfg)
  int rc;
  int port;
 
- if(cfg->port < 0){
+ if(cfg->port == PORT_UNDEFINED){
 #ifdef WITH_TLS
  if(cfg->cafile || cfg->capath
 # ifdef FINAL_WITH_TLS_PSK

client/client_shared.h

@@ -38,6 +38,9 @@ and the Eclipse Distribution License is available at
 #define CLIENT_RR 3
 #define CLIENT_RESPONSE_TOPIC 4
 
+#define PORT_UNDEFINED -1
+#define PORT_UNIX 0
+
 struct mosq_config {
  char *id;
  char *id_prefix;

client/pub_client.c

@@ -345,7 +345,7 @@ void print_usage(void)
  mosquitto_lib_version(&major, &minor, &revision);
  printf("mosquitto_pub is a simple mqtt client that will publish a message on a single topic and exit.\n");
  printf("mosquitto_pub version %s running on libmosquitto %d.%d.%d.\n\n", VERSION, major, minor, revision);
- printf("Usage: mosquitto_pub {[-h host] [-p port] [-u username] [-P password] -t topic | -L URL}\n");
+ printf("Usage: mosquitto_pub {[-h host] [--unix path] [-p port] [-u username] [-P password] -t topic | -L URL}\n");
  printf(" {-f file | -l | -n | -m message}\n");
  printf(" [-c] [-k keepalive] [-q qos] [-r] [--repeat N] [--repeat-delay time]\n");
 #ifdef WITH_SRV
@@ -405,6 +405,8 @@ void print_usage(void)
  printf(" --repeat : if publish mode is -f, -m, or -s, then repeat the publish N times.\n");
  printf(" --repeat-delay : if using --repeat, wait time seconds between publishes. Defaults to 0.\n");
  printf(" --quiet : don't print error messages.\n");
+ printf(" --unix : connect to a broker through a unix domain socket instead of a TCP socket,\n");
+ printf(" e.g. /tmp/mosquitto.sock\n");
  printf(" --will-payload : payload for the client Will, which is sent by the broker in case of\n");
  printf(" unexpected disconnection. If not given and will-topic is set, a zero\n");
  printf(" length message will be sent.\n");

client/rr_client.c

@@ -162,7 +162,7 @@ void print_usage(void)
  printf(" Defaults to MQTT v5, where the Request-Response feature will be used, but v3.1.1 can also be used\n");
  printf(" with v3.1.1 brokers.\n");
  printf("mosquitto_rr version %s running on libmosquitto %d.%d.%d.\n\n", VERSION, major, minor, revision);
- printf("Usage: mosquitto_rr {[-h host] [-p port] [-u username] [-P password] -t topic | -L URL} -e response-topic\n");
+ printf("Usage: mosquitto_rr {[-h host] [--unix path] [-p port] [-u username] [-P password] -t topic | -L URL} -e response-topic\n");
  printf(" [-c] [-k keepalive] [-q qos] [-R]\n");
  printf(" [-F format]\n");
 #ifndef WIN32
@@ -219,6 +219,8 @@ void print_usage(void)
 #endif
  printf(" --help : display this message.\n");
  printf(" --quiet : don't print error messages.\n");
+ printf(" --unix : connect to a broker through a unix domain socket instead of a TCP socket,\n");
+ printf(" e.g. /tmp/mosquitto.sock\n");
  printf(" --will-payload : payload for the client Will, which is sent by the broker in case of\n");
  printf(" unexpected disconnection. If not given and will-topic is set, a zero\n");
  printf(" length message will be sent.\n");

client/sub_client.c

@@ -176,7 +176,7 @@ void print_usage(void)
  mosquitto_lib_version(&major, &minor, &revision);
  printf("mosquitto_sub is a simple mqtt client that will subscribe to a set of topics and print all messages it receives.\n");
  printf("mosquitto_sub version %s running on libmosquitto %d.%d.%d.\n\n", VERSION, major, minor, revision);
- printf("Usage: mosquitto_sub {[-h host] [-p port] [-u username] [-P password] -t topic | -L URL [-t topic]}\n");
+ printf("Usage: mosquitto_sub {[-h host] [--unix path] [-p port] [-u username] [-P password] -t topic | -L URL [-t topic]}\n");
  printf(" [-c] [-k keepalive] [-q qos]\n");
  printf(" [-C msg_count] [-E] [-R] [--retained-only] [--remove-retained] [-T filter_out] [-U topic ...]\n");
  printf(" [-F format]\n");
@@ -244,6 +244,8 @@ void print_usage(void)
  printf(" first non-retained message is received.\n");
  printf(" --remove-retained : send a message to the server to clear any received retained messages\n");
  printf(" Use -T to filter out messages you do not want to be cleared.\n");
+ printf(" --unix : connect to a broker through a unix domain socket instead of a TCP socket,\n");
+ printf(" e.g. /tmp/mosquitto.sock\n");
  printf(" --will-payload : payload for the client Will, which is sent by the broker in case of\n");
  printf(" unexpected disconnection. If not given and will-topic is set, a zero\n");
  printf(" length message will be sent.\n");

config.mk

@@ -97,6 +97,9 @@ WITH_BUNDLED_DEPS:=yes
 # Build with coverage options
 WITH_COVERAGE:=no
 
+# Build with unix domain socket support
+WITH_UNIX_SOCKETS:=yes
+
 # =============================================================================
 # End of user configuration
 # =============================================================================
@@ -272,6 +275,12 @@ ifeq ($(WITH_DOCS),yes)
  MAKE_ALL:=$(MAKE_ALL) docs
 endif
 
+ifeq ($(WITH_UNIX_SOCKETS),yes)
+ BROKER_CPPFLAGS:=$(BROKER_CPPFLAGS) -DWITH_UNIX_SOCKETS
+ LIB_CPPFLAGS:=$(LIB_CPPFLAGS) -DWITH_UNIX_SOCKETS
+ CLIENT_CPPFLAGS:=$(CLIENT_CPPFLAGS) -DWITH_UNIX_SOCKETS
+endif
+
 ifeq ($(WITH_WEBSOCKETS),yes)
  BROKER_CPPFLAGS:=$(BROKER_CPPFLAGS) -DWITH_WEBSOCKETS
  BROKER_LDADD:=$(BROKER_LDADD) -lwebsockets

lib/connect.c

@@ -42,7 +42,7 @@ static int mosquitto__connect_init(struct mosquitto *mosq, const char *host, int
  int rc;
 
  if(!mosq) return MOSQ_ERR_INVAL;
- if(!host || port <= 0) return MOSQ_ERR_INVAL;
+ if(!host || port < 0) return MOSQ_ERR_INVAL;
 
  /* Only MQTT v3.1 requires a client id to be sent */
  if(mosq->id == NULL && (mosq->protocol == mosq_p_mqtt31)){
@@ -160,7 +160,7 @@ static int mosquitto__reconnect(struct mosquitto *mosq, bool blocking, const mos
  int rc;
 
  if(!mosq) return MOSQ_ERR_INVAL;
- if(!mosq->host || mosq->port <= 0) return MOSQ_ERR_INVAL;
+ if(!mosq->host || mosq->port < 0) return MOSQ_ERR_INVAL;
  if(mosq->protocol != mosq_p_mqtt5 && properties) return MOSQ_ERR_NOT_SUPPORTED;
 
  if(properties){

lib/net_mosq.c

@@ -42,6 +42,10 @@ and the Eclipse Distribution License is available at
 # include <netinet/in.h>
 #endif
 
+#ifdef WITH_UNIX_SOCKETS
+# include <sys/un.h>
+#endif
+
 #ifdef __QNX__
 #include <net/netbyte.h>
 #endif
@@ -364,7 +368,7 @@ int net__try_connect_step2(struct mosquitto *mosq, uint16_t port, mosq_sock_t *s
 #endif
 
 
-int net__try_connect(const char *host, uint16_t port, mosq_sock_t *sock, const char *bind_address, bool blocking)
+static int net__try_connect_tcp(const char *host, uint16_t port, mosq_sock_t *sock, const char *bind_address, bool blocking)
 {
  struct addrinfo hints;
  struct addrinfo *ainfo, *rp;
@@ -461,6 +465,55 @@ int net__try_connect(const char *host, uint16_t port, mosq_sock_t *sock, const c
 }
 
 
+#ifdef WITH_UNIX_SOCKETS
+static int net__try_connect_unix(const char *host, mosq_sock_t *sock)
+{
+ struct sockaddr_un addr;
+ int s;
+ int rc;
+
+ if(host == NULL || strlen(host) == 0 || strlen(host) > sizeof(addr.sun_path)-1){
+ return MOSQ_ERR_INVAL;
+ }
+
+ memset(&addr, 0, sizeof(struct sockaddr_un));
+ addr.sun_family = AF_UNIX;
+ strncpy(addr.sun_path, host, sizeof(addr.sun_path)-1);
+
+ s = socket(AF_UNIX, SOCK_STREAM, 0);
+ if(s < 0){
+ return MOSQ_ERR_ERRNO;
+ }
+ rc = net__socket_nonblock(&s);
+ if(rc) return rc;
+
+ rc = connect(s, (struct sockaddr *)&addr, sizeof(struct sockaddr_un));
+ if(rc < 0){
+ close(s);
+ return MOSQ_ERR_ERRNO;
+ }
+
+ *sock = s;
+
+ return 0;
+}
+#endif
+
+
+int net__try_connect(const char *host, uint16_t port, mosq_sock_t *sock, const char *bind_address, bool blocking)
+{
+ if(port == 0){
+#ifdef WITH_UNIX_SOCKETS
+ return net__try_connect_unix(host, sock);
+#else
+ return MOSQ_ERR_NOT_SUPPORTED;
+#endif
+ }else{
+ return net__try_connect_tcp(host, port, sock, bind_address, blocking);
+ }
+}
+
+
 #ifdef WITH_TLS
 void net__print_ssl_error(struct mosquitto *mosq)
 {
@@ -827,7 +880,7 @@ int net__socket_connect(struct mosquitto *mosq, const char *host, uint16_t port,
  mosq_sock_t sock = INVALID_SOCKET;
  int rc, rc2;
 
- if(!mosq || !host || !port) return MOSQ_ERR_INVAL;
+ if(!mosq || !host || port < 0) return MOSQ_ERR_INVAL;
 
  rc = net__try_connect(host, port, &sock, bind_address, blocking);
  if(rc > 0) return rc;

lib/tls_mosq.c

@@ -56,7 +56,11 @@ int mosquitto__server_certificate_verify(int preverify_ok, X509_STORE_CTX *ctx)
  mosq = SSL_get_ex_data(ssl, tls_ex_index_mosq);
  if(!mosq) return 0;
 
- if(mosq->tls_insecure == false){
+ if(mosq->tls_insecure == false
+#ifndef WITH_BROKER
+ && mosq->port != 0 /* no hostname checking for unix sockets */
+#endif
+ ){
  if(X509_STORE_CTX_get_error_depth(ctx) == 0){
  /* FIXME - use X509_check_host() etc. for sufficiently new openssl (>=1.1.x) */
  cert = X509_STORE_CTX_get_current_cert(ctx);

man/mosquitto.conf.5.xml

@@ -1159,7 +1159,7 @@ log_timestamp_format %Y-%m-%dT%H:%M:%S
  </listitem>
  </varlistentry>
  <varlistentry>
- <term><option>socket_domain</option> [ ipv4 | ipv6 ]</term>
+ <term><option>socket_domain</option> [ ipv4 | ipv6 | unix ] [path to unix socket]</term>
  <listitem>
  <para>By default, a listener will attempt to listen on
  all supported IP protocol versions. If you do not
@@ -1176,6 +1176,10 @@ log_timestamp_format %Y-%m-%dT%H:%M:%S
  use IPv6. If you want support for both IPv4 and
  IPv6, then do not use the
  <option>socket_domain</option> option.</para>
+ <para>On systems that support Unix Domain Sockets, this
+ option can also be used to create a Unix socket rather
+ than opening a TCP socket. In this case, the option
+ should be in the form: <option>socket_domain unix &lt;path to socket&gt;</option>. For example: <option>socket_domain unix /tmp/mosquitto.sock</option></para>
  <para>Not reloaded on reload signal.</para>
  </listitem>
  </varlistentry>

man/mosquitto_pub.1.xml

@@ -20,6 +20,7 @@
  <group choice='req'>
  <arg choice='plain'>
  <arg><option>-h</option> <replaceable>hostname</replaceable></arg>
+ <arg><option>--unix</option> <replaceable>socket path</replaceable></arg>
  <arg><option>-p</option> <replaceable>port-number</replaceable></arg>
  <arg><option>-u</option> <replaceable>username</replaceable></arg>
  <arg><option>-P</option> <replaceable>password</replaceable></arg>
@@ -537,6 +538,21 @@
  argument.</para>
  </listitem>
  </varlistentry>
+ <varlistentry>
+ <term><option>--unix</option></term>
+ <listitem>
+ <para>Connect to a broker through a local unix domain socket
+ instead of a TCP socket. This is a replacement for
+ <option>-h</option> and <option>-L</option>. For example:
+ <option>mosquitto_pub --unix /tmp/mosquitto.sock ...</option>
+ </para>
+ <para>See the <option>socket_domain</option> option in
+ <refentrytitle>
+ <link xlink:href="mosquitto-conf-5.html">mosquitto.conf</link>
+ </refentrytitle><manvolnum>5</manvolnum>
+ to configure Mosquitto to listen on a unix socket.</para>
+ </listitem>
+ </varlistentry>
  <varlistentry>
  <term><option>-V</option></term>
  <term><option>--protocol-version</option></term>

man/mosquitto_rr.1.xml

@@ -20,6 +20,7 @@
  <group choice='req'>
  <arg choice='plain'>
  <arg><option>-h</option> <replaceable>hostname</replaceable></arg>
+ <arg><option>--unix</option> <replaceable>socket path</replaceable></arg>
  <arg><option>-p</option> <replaceable>port-number</replaceable></arg>
  <arg><option>-u</option> <replaceable>username</replaceable></arg>
  <arg><option>-P</option> <replaceable>password</replaceable></arg>
@@ -545,6 +546,21 @@
  argument.</para>
  </listitem>
  </varlistentry>
+ <varlistentry>
+ <term><option>--unix</option></term>
+ <listitem>
+ <para>Connect to a broker through a local unix domain socket
+ instead of a TCP socket. This is a replacement for
+ <option>-h</option> and <option>-L</option>. For example:
+ <option>mosquitto_pub --unix /tmp/mosquitto.sock ...</option>
+ </para>
+ <para>See the <option>socket_domain</option> option in
+ <refentrytitle>
+ <link xlink:href="mosquitto-conf-5.html">mosquitto.conf</link>
+ </refentrytitle><manvolnum>5</manvolnum>
+ to configure Mosquitto to listen on a unix socket.</para>
+ </listitem>
+ </varlistentry>
  <varlistentry>
  <term><option>-v</option></term>
  <term><option>--verbose</option></term>

man/mosquitto_sub.1.xml

@@ -20,6 +20,7 @@
  <group choice='req'>
  <arg choice='plain'>
  <arg><option>-h</option> <replaceable>hostname</replaceable></arg>
+ <arg><option>--unix</option> <replaceable>socket path</replaceable></arg>
  <arg><option>-p</option> <replaceable>port-number</replaceable></arg>
  <arg><option>-u</option> <replaceable>username</replaceable></arg>
  <arg><option>-P</option> <replaceable>password</replaceable></arg>
@@ -618,6 +619,21 @@ mosquitto_sub -t 'bbc/#' -T bbc/bbc1 --remove-retained</programlisting>
  argument.</para>
  </listitem>
  </varlistentry>
+ <varlistentry>
+ <term><option>--unix</option></term>
+ <listitem>
+ <para>Connect to a broker through a local unix domain socket
+ instead of a TCP socket. This is a replacement for
+ <option>-h</option> and <option>-L</option>. For example:
+ <option>mosquitto_pub --unix /tmp/mosquitto.sock ...</option>
+ </para>
+ <para>See the <option>socket_domain</option> option in
+ <refentrytitle>
+ <link xlink:href="mosquitto-conf-5.html">mosquitto.conf</link>
+ </refentrytitle><manvolnum>5</manvolnum>
+ to configure Mosquitto to listen on a unix socket.</para>
+ </listitem>
+ </varlistentry>
  <varlistentry>
  <term><option>-U</option></term>
  <term><option>--unsubscribe</option></term>