Socket AT commands

Socket #XSOCKET
Secure Socket #XSSOCKET
Select Socket #XSOCKETSELECT
Socket options #XSOCKETOPT
Secure Socket options #XSOCKETOPT
Socket binding #XBIND
Connection #XCONNECT
Set listen mode #XLISTEN
Accept connection #XACCEPT
Send data #XSEND
Receive data #XRECV
UDP send data #XSENDTO
UDP receive data #XRECVFROM
Poll sockets #XPOLL
Resolve hostname #XGETADDRINFO

The following commands list contains socket-related AT commands. The application can open up to 8 sockets and select the active one among them.

For more information on the networking services, visit the BSD Networking Services Spec Reference.

Socket #XSOCKET 

The #XSOCKET command allows you to open or close a socket and to check the socket handle.

Set command 

The set command allows you to open or close a socket.

Syntax

#XSOCKET=<op>[,<type>,<role>]]

The <op> parameter can accept one of the following values:
- 0 - Close a socket.
- 1 - Open a socket for IP protocol family version 4.
- 2 - Open a socket for IP protocol family version 6.
When 0, the highest-ranked socket is made active after the current one is closed.
The <type> parameter can accept one of the following values:
- 1 - Set SOCK_STREAM for the stream socket type using the TCP protocol.
- 2 - Set SOCK_DGRAM for the datagram socket type using the UDP protocol.
- 3 - Set SOCK_RAW for the raw socket type using a generic IP protocol.
The <role> parameter can accept one of the following values:
- 0 - Client
- 1 - Server

Response syntax

#XSOCKET: <handle>[,<type>,<protocol>]

The <handle> value is an integer and can be interpreted as follows:
- Positive - The socket opened successfully.
- Negative - The socket failed to open.
The <type> value can be one of the following integers:
- 1 - Set SOCK_STREAM for the stream socket type using the TCP protocol.
- 2 - Set SOCK_DGRAM for the datagram socket type using the UDP protocol.
- 3 - Set SOCK_RAW for the raw socket type using a generic IP protocol.
The <protocol> value can be one of the following integers:
- 0 - IPPROTO_IP
- 6 - IPPROTO_TCP
- 17 - IPPROTO_UDP

Examples

AT#XSOCKET=1,1,0
#XSOCKET: 3,1,6
OK
AT#XSOCKET=1,2,0
#XSOCKET: 1,2,17
OK
AT#XSOCKET=2,1,0
#XSOCKET: 1,1,6
OK
AT#XSOCKET=1,3,0
#XSOCKET: 1,3,0
OK
AT#XSOCKET=0
#XSOCKET: 0,"closed"
OK

Read command 

The read command allows you to check the socket handle.

Syntax

#XSOCKET?

Response syntax

#XSOCKET: <handle>[,<family>,<role>]

The <handle> value is an integer and can be interpreted as follows:
- Positive - The socket is valid.
- 0 - The socket is closed.
The <family> value is present only in the response to a request to open the socket. It can assume one of the following values:
- 1 - IP protocol family version 4.
- 2 - IP protocol family version 6.
- 3 - Packet family.
The <role> value can be one of the following integers:
- 0 - Client
- 1 - Server

Examples

AT#XSOCKET?
#XSOCKET: 3,1,0
OK

Test command 

The test command tests the existence of the command and provides information about the type of its subparameters.

Syntax

#XSOCKET=?

Response syntax

#XSOCKET: <list of op>,<list of types>,<list of roles>

The <list of op> value can be one of the following integers:
- 0 - Close a socket.
- 1 - Open a socket for IP protocol family version 4.
- 2 - Open a socket for IP protocol family version 6.
The <list of types> value can be one of the following integers:
- 1 - Set SOCK_STREAM for the stream socket type using the TCP protocol.
- 2 - Set SOCK_DGRAM for the datagram socket type using the UDP protocol.
- 3 - Set SOCK_RAW for the raw socket type using a generic IP protocol.
The <list of roles> value can be one of the following integers:
- 0 - Client
- 1 - Server

Examples

AT#XSOCKET=?
#XSOCKET: (0,1,2),(1,2,3),(0,1)
OK

Secure Socket #XSSOCKET 

The #XSSOCKET command allows you to open or close a secure socket, and to check the socket handle.

Note

TLS and DTLS servers are currently not supported.

Set command 

The set command allows you to open or close a secure socket.

Syntax

#XSSOCKET=<op>[,<type>,<role>,<sec_tag>[,<peer_verify>]]

The <op> parameter can accept one of the following values:
- 0 - Close a socket.
- 1 - Open a socket for IP protocol family version 4.
- 2 - Open a socket for IP protocol family version 6.
When 0, the highest-ranked socket is made active after the current one is closed.
The <type> parameter can accept one of the following values:
- 1 - Set SOCK_STREAM for the stream socket type using the TLS 1.2 protocol.
- 2 - Set SOCK_DGRAM for the datagram socket type using the DTLS 1.2 protocol.
The <role> parameter can accept one of the following values:
- 0 - Client
- 1 - Server
The <sec_tag> parameter is an integer. It indicates to the modem the credential of the security tag to be used for establishing a secure connection. It is associated with a credential, that is, a certificate or PSK. The credential should be stored on the modem side beforehand.
The <peer_verify> parameter can accept one of the following values:
- 0 - None (default for server role)
- 1 - Optional
- 2 - Required (default for client role)

Response syntax

#XSSOCKET: <handle>[,<type>,<protocol>]

The <handle> value is an integer and can be interpreted as follows:
- Positive - The socket opened successfully.
- Negative - The socket failed to open.
The <type> value can be one of the following integers:
- 1 - SOCK_STREAM for the stream socket type using the TLS 1.2 protocol.
- 2 - SOCK_DGRAM for the datagram socket type using the DTLS 1.2 protocol.
The <protocol> value can be one of the following integers:
- 258 - IPPROTO_TLS_1_2
- 273 - IPPROTO_DTLS_1_2

Examples

AT#XSSOCKET=1,1,0,16842753,2
#XSSOCKET: 2,1,258
OK
AT#XSOCKET=0
#XSOCKET: 0,"closed"
OK

AT#XSSOCKET=1,2,0,16842753
#XSSOCKET: 2,2,273
OK
AT#XSOCKET=0
#XSOCKET: 0,"closed"
OK

Read command 

The read command allows you to check the secure socket handle.

Syntax

#XSSOCKET?

Response syntax

#XSSOCKET: <handle>[,<family>,<role>]

The <handle> value is an integer and can be interpreted as follows:
- Positive - The socket is valid.
- 0 - The socket is closed.
The <family> value can be one of the following integers:
- 1 - IP protocol family version 4.
- 2 - IP protocol family version 6.
The <role> value can be one of the following integers:
- 0 - Client
- 1 - Server

Examples

AT#XSSOCKET?
#XSSOCKET: 2,1,0
OK

Test command 

The test command tests the existence of the command and provides information about the type of its subparameters.

Syntax

#XSSOCKET=?

Response syntax

#XSSOCKET: <list of op>,<list of types>,<list of roles>,<sec-tag>,<peer_verify>

The <list of op> value can be one of the following integers:
- 0 - Close a secure socket.
- 1 - Open a secure socket for IP protocol family version 4.
- 2 - Open a secure socket for IP protocol family version 6.
The <list of types>> value can be one of the following integers.
- 1 - SOCK_STREAM for the stream socket type using the TLS 1.2 protocol.
- 2 - SOCK_DGRAM for the datagram socket type using the DTLS 1.2 protocol.
The <list of roles> value can be one of the following integers:
- 0 - Client
- 1 - Server

Examples

AT#XSSOCKET=?
#XSSOCKET: (0,1,2),(1,2),<sec_tag>,<peer_verify>,<hostname_verify>
OK

Select Socket #XSOCKETSELECT 

The #XSOCKETSELECT command allows you to select an active socket among multiple opened ones.

Set command 

The set command allows you to select an active socket.

Syntax

#XSOCKETSELECT=<handle>

The <handle> parameter is the handle value returned from the #XSOCKET or #XSSOCKET commands.

Response syntax

#XSOCKETSELECT: <handle>,<family>,<role>

The <handle> value is an integer. When positive, the socket is valid.
The <family> value can be one of the following integers:
- 1 - IP protocol family version 4.
- 2 - IP protocol family version 6.
The <role> value can be one of the following integers:
- 0 - Client
- 1 - Server

Examples

AT#XSOCKETSELECT=4
#XSOCKETSELECT: 4,1,1
OK

Read command 

The read command allows you to list all sockets that have been opened and the active socket.

Syntax

#XSOCKETSELECT?

Response syntax

#XSOCKETSELECT: <handle>,<family>,<role>,<type>,<sec_tag>,<ranking>
#XSOCKETSELECT: <handle_active>

The <handle> value is an integer that indicates the handle of the socket.
The <family> value can be one of the following integers:
- 1 - IP protocol family version 4.
- 2 - IP protocol family version 6.
The <role> value can be one of the following integers:
- 0 - Client
- 1 - Server
The <type> value can assume one of the following values:
- 1 - Set SOCK_STREAM for the stream socket type using the TLS 1.2 protocol.
- 2 - Set SOCK_DGRAM for the datagram socket type using the DTLS 1.2 protocol.
The <sec_tag> value is an integer. It indicates to the modem the credential of the security tag to be used for establishing a secure connection. For a non-secure socket, it assumes the value of -1.
The <ranking> value is an integer. It indicates the ranking value of this socket, where the largest value means the highest ranking.
The <handle_active> value is an integer that indicates the handle of the active socket.

Examples

AT#XSOCKETSELECT?
#XSOCKETSELECT: 0,1,0,1,-1,2
#XSOCKETSELECT: 1,1,0,2,-1,3
#XSOCKETSELECT: 2,1,0,1,16842755,4
#XSOCKETSELECT: 3,1,0,2,16842755,5
#XSOCKETSELECT: 4,1,1,1,-1,6
#XSOCKETSELECT: 5,1,1,2,-1,7
#XSOCKETSELECT: 6,1,1,1,16842755,8
#XSOCKETSELECT: 7,1,0,1,-1,9
#XSOCKETSELECT: 7
OK

AT#XSOCKETSELECT=4
#XSOCKETSELECT: 4,1,1
OK

AT#XSOCKETSELECT?
#XSOCKETSELECT: 0,1,0,1,-1,2
#XSOCKETSELECT: 1,1,0,2,-1,3
#XSOCKETSELECT: 2,1,0,1,16842755,4
#XSOCKETSELECT: 3,1,0,2,16842755,5
#XSOCKETSELECT: 4,1,1,1,-1,6
#XSOCKETSELECT: 5,1,1,2,-1,7
#XSOCKETSELECT: 6,1,1,1,16842755,8
#XSOCKETSELECT: 7,1,0,1,-1,9
#XSOCKETSELECT: 4
OK

Test command 

The test command is not supported.

Socket options #XSOCKETOPT 

The #XSOCKETOPT command allows you to get and set socket options.

Set command 

The set command allows you to get and set socket options.

Syntax

#XSOCKETOPT=<op>,<name>[,<value>]

The <op> parameter can accept one of the following values:
- 0 - Get
- 1 - Set

For a complete list of the supported SET <name> accepted parameters, see the SETSOCKETOPT Service Spec Reference.

For a complete list of the supported GET <name> accepted parameters, see the GETSOCKETOPT Service Spec Reference.

Examples

AT#XSOCKETOPT=1,20,30
OK

AT#XSOCKETOPT=0,20
#XSOCKETOPT: 30
OK

Read command 

The read command is not supported.

Test command 

The test command tests the existence of the command and provides information about the type of its subparameters.

Syntax

#XSOCKETOPT=?

Response syntax

#XSOCKETOPT: <list of op>,<name>,<value>

Examples

AT#XSOCKETOPT=?
#XSOCKETOPT: (0,1),<name>,<value>
OK

Secure Socket options #XSOCKETOPT 

The #XSSOCKETOPT command allows you to set secure socket options.

Set command 

The set command allows you to set secure socket options.

Syntax

#XSSOCKETOPT=<op>,<name>[,<value>]

The <op> parameter can accept one of the following values:
- 0 - Get
- 1 - Set
The <name> parameter can accept one of the following values:
- 2 - TLS_HOSTNAME. <value> is a string.
- 4 - TLS_CIPHERSUITE_USED (get-only). It returns the IANA assigned ciphersuite identifier of the chosen ciphersuite.
- 5 - TLS_PEER_VERIFY. <value> is an integer and can be either 0 or 1.
- 10 - TLS_SESSION_CACHE. <value> is an integer and can be either 0 or 1.
- 11 - TLS_SESSION_CACHE_PURGE. <value> can assume any integer value.
- 12 - TLS_DTLS_HANDSHAKE_TIMEO. <value> is the timeout in seconds and can be one of the following integers: 1, 3, 7, 15, 31, 63, 123.

For a complete list of the supported <name> accepted parameters, see the SETSOCKETOPT Service Spec Reference.

Examples

AT#XSSOCKETOPT=1,5,2
OK

Read command 

The read command is not supported.

Test command 

The test command tests the existence of the command and provides information about the type of its subparameters.

Syntax

#XSSOCKETOPT=?

Response syntax

#XSSOCKETOPT: <list of op>,<name>,<value>

Examples

AT#XSSOCKETOPT=?
#XSSOCKETOPT: (1),<name>,<value>
OK

Socket binding #XBIND 

The #XBIND command allows you to bind a socket with a local port.

This command can be used with TCP servers and both UDP clients and servers.

Set command 

The set command allows you to bind a socket with a local port.

Syntax

#XBIND=<port>

The <port> parameter is an unsigned 16-bit integer (0 - 65535). It represents the specific port to use for binding the socket.

Examples

AT#XBIND=1234
OK

Syntax

#XCONNECT=<url>,<port>

The <url> parameter is a string. It indicates the hostname or the IP address of the server. The maximum supported size of the hostname is 128 bytes. When using IP addresses, it supports both IPv4 and IPv6.
The <port> parameter is an unsigned 16-bit integer (0 - 65535). It represents the port of the TCP or UDP service on the remote server.

Response syntax

#XCONNECT: <status>

The <status> value is an integer. It can assume one of the following values:
1 - Connected
0 - Disconnected

Examples

AT#XCONNECT="test.server.com",1234
#XCONNECT: 1
OK

AT#XCONNECT="192.168.0.1",1234
#XCONNECT: 1
OK

AT#XCONNECT="2a02:c207:2051:8976::1",4567
#XCONNECT: 1
OK

Syntax

#XLISTEN

Response syntax

There is no response.

Examples

AT#XLISTEN
OK

Syntax

#XACCEPT=<timeout>

The <timeout> value sets the timeout value in seconds. 0 means no timeout, and it makes this request become blocking.

Response syntax

#XACCEPT: <handle>,<ip_addr>

The <handle> value is an integer. It represents the socket handle of the accepted connection.
The <ip_addr> value indicates the IP address of the peer host.

Examples

AT#XACCEPT=60
#XACCEPT: 2,"192.168.0.2"
OK

Read command 

The read command allows you to check socket handle of the accepted connection.

Syntax

#XACCEPT?

Response syntax

#XACCEPT: <handle>

The <handle> value is an integer and can be interpreted as follows:
- Positive - The incoming socket is valid.
- 0 - There is no active incoming connection.

Examples

AT#XACCEPT?
#XACCEPT: 192.168.0.2
OK

Syntax

#XSEND[=<data>]

The <data> parameter is a string that contains the data to be sent. The maximum size of the data is 1252 bytes. When the parameter is not specified, SLM enters slm_data_mode.

Response syntax

#XSEND: <size>

The <size> value is an integer. It represents the actual number of bytes that has been sent.

Examples

AT#XSEND="Test TCP"
#XSEND: 8
OK

Syntax

#XRECV=<timeout>

The <timeout> value sets the timeout value in seconds. 0 means no timeout, and it makes this request become blocking.

Response syntax

<data>
#XRECV: <size>

The <data> value is a string that contains the data being received.
The <size> value is an integer that represents the actual number of bytes received.

Examples

AT#XRECV=10
Test OK
#XRECV: 7
OK

Syntax

#XSENDTO=<url>,<port>[,<data>]

The <url> parameter is a string. It indicates the hostname or the IP address of the remote peer. The maximum size of the hostname is 128 bytes. When using IP addresses, it supports both IPv4 and IPv6.
The <port> parameter is an unsigned 16-bit integer (0 - 65535). It represents the port of the UDP service on remote peer.
The <data> parameter is a string that contains the data to be sent. Its maximum size is 1252 bytes. When the parameter is not specified, SLM enters slm_data_mode.

Response syntax

#XSENDTO: <size>

The <size> value is an integer. It represents the actual number of bytes that has been sent.

Examples

AT#XSENDTO="test.server.com",1234,"Test UDP"
#XSENDTO: 8
OK

Syntax

#XRECVFROM=<timeout>

The <timeout> value sets the timeout value in seconds. 0 means no timeout, and it makes this request become blocking.

Response syntax

<data>
#XRECVFROM: <size>,<ip_addr>

The <data> value is a string that contains the data being received.
The <size> value is an integer that represents the actual number of bytes received.
The <ip_addr> value is an string that represents the IPv4 or IPv6 address of remote peer.

Examples

AT#XRECVFROM=10
Test OK
#XRECVFROM: 7,"192.168.1.100"
OK

Syntax

#XPOLL=<timeout>[,<handle1>[,<handle2> ...<handle8>]

The <timeout> value sets the timeout value in milliseconds, and the poll blocks up to this timeout. 0 means no timeout, and the poll returns without blocking. -1 means indefinite, and the poll blocks indefinitely until any events are received.
The <handleN> value sets the socket handles to poll. The handles values could be obtained by AT#XSOCKETSELECT? command. If no handle values are specified, all opened sockets will be polled.

Response syntax

#XPOLL: <error>
#XPOLL: <handle>,<revents>

The <error> value is an error code when the poll fails.
The <handle> value is an integer. It is the handle of a socket that have events returned, so-called revents.
The <revents> value is a hexadecimal string. It represents the returned events, which could be a combination of POLLIN, POLLERR, POLLHUP and POLLNVAL.

Examples

AT#XPOLL=2000,0
#XPOLL: 0,"0x00000001"
OK

AT#XPOLL=2000,1
#XPOLL: 1,"0x00000001"
OK

AT#XPOLL=2000
#XPOLL: 0,"0x00000001"
#XPOLL: 1,"0x00000001"
OK

Syntax

#XGETADDRINFO=<hostname>

The <hostname> parameter is a string.

Response syntax

#XGETADDRINFO: "<ip_addresses>"

The <ip_addresses> value is a string. It indicates the IPv4 or IPv6 address of the resolved hostname.

Examples

at#xgetaddrinfo="www.google.com"
#XGETADDRINFO: "172.217.174.100"
OK

Read command 

The read command is not supported.

Test command 

The test command is not supported.