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Internet-Draft This document describes a BSD Sockets-like API on top of the callback-based NEAT User API. This facilitates porting existing applications to use a subset of NEAT's functionality.

Introduction The NEAT project , , , , wants to achieve a complete redesign of the way in which Internet applications interact with the network. Our goal is to allow network "services" offered to applications - such as reliability, low-delay communication or security - to be dynamically tailored based on application demands, current network conditions, hardware capabilities or local policies, and also to support the integration of new network functionality in an evolutionary fashion. This document describes the NEAT Sockets API on top of the callback-based NEAT User API . It provides a BSD Sockets-like API that facilitates porting existing applications to use a subset of NEAT's functionality. For further information on NEAT, see also , , , , .

Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in .

Initialisation and Clean-Up

nsa_init() nsa_init() is used to explicitly initialise the NEAT Sockets API. In the usual case, however, the NEAT Sockets API is automatically initialized when creating a NEAT socket. Explicit initialisation may only be necessary in a multi-threaded program, in order to avoid parallel initialisation calls. Function Prototype: Return Value: nsa_init() returns the new NEAT socket descriptor, or -1 in case of error. The error code will be set in the errno variable.

nsa_cleanup() nsa_cleanup() is used to free all resources allocated by NEAT. Note, that the NEAT Sockets API is automatically initialized when creating a NEAT socket. Function Prototype:

nsa_map_socket() nsa_map_socket() is used to map a system socket descriptor into the NEAT socket descriptor space. This is useful for using NEAT API functions as wrapper to calls on non-NEAT sockets. Mapped socket descriptors can be unmapped by using nsa_unmap_socket(). Function Prototype: Arguments:

systemSD:

System socket descriptor.

neatSD:

Desired NEAT socket descriptor; -1 for automatic allocation.

Return Value: nsa_map_socket() returns the new NEAT socket descriptor, or -1 in case of error. The error code will be set in the errno variable.

nsa_unmap_socket() nsa_unmap_socket() is used to unmap a system socket descriptor from the NEAT socket descriptor space. Function Prototype: Arguments:

neatSD:

NEAT socket descriptor.

Connection Establishment and Teardown

nsa_socket() nsa_socket() creates a new NEAT socket. The NEAT socket can either be a wrapper around the NEAT User API (if properties are specified) or be a wrapper around a system socket (if no properties are specified). Function Prototype: Arguments:

domain:

Domain for system socket (e.g. AF_INET).

type:

Type for system socket (SOCK_SEQPACKET).

protocol:

Protocol for system socket (IPPROTO_SCTP).

properties:

Properties for NEAT Core socket.

Return Value: nsa_socket() returns the NEAT socket descriptor in case of success, or -1 in case of error. The error code will be set in the errno variable. See the socket() documentation for details.

nsa_socketpair() nsa_socketpair() is a wrapper around the socketpair() call, returning NEAT socket descriptors instead. Note, that socketpair() only supports AF_UNIX sockets, i.e. this function is just a wrapper for the system function. Function Prototype: See the socketpair() documentation for details.

nsa_close() nsa_close() closes a given NEAT socket. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

nsa_close() returns 0 in case of success, or -1 in case of error. The error code will be set in the errno variable. See the close() documentation for details.

nsa_fcntl() nsa_fcntl() manipulates a given NEAT socket. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

cmd:

Command.

...:

Command-specific arguments.

nsa_fcntl() returns a command-specific value. For NEAT sockets, the following commands are specified:

F_GETFL:

Obtain value of the socket descriptor status flags. For NEAT sockets, the flag O_NONBLOCK specifies whether the socket is non-blocking. By default, it is blocking (i.e. O_NONBLOCK is not set).

F_SETFL:

Set value of the socket descriptor status flags. For NEAT sockets, the flag O_NONBLOCK specifies whether the socket is non-blocking. By default, it is blocking (i.e. O_NONBLOCK is not set). F_SETFL can then be used to change the blocking mode.

See the fcntl() documentation for details.

nsa_bind() nsa_bind() binds a given NEAT socket to a given address. Note: this function is provided as legacy wrapper, and it is RECOMMENDED to use nsa_bindn() instead. Note further, that nsa_bind() also supports a single address only (i.e. no multi-homing). nsa_bindx() SHOULD be used instead to support multi-homing. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

addr:

Address to bind to.

addrlen:

Length of the address structure "addr".

opt:

NEAT options (NULL, if there are none).

optcnt:

Number of NEAT options provided by "opt".

nsa_bind() returns 0 in case of success, or -1 in case of error. The error code will be set in the errno variable. See the bind() documentation for details.

nsa_bindx() nsa_bindx() binds a given NEAT socket to a given set of addresses. Note: this function is provided as legacy wrapper, and it is RECOMMENDED to use nsa_bindn() instead. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

addrs:

Addresses to bind to.

addrcnt:

Number of addresses in "addr".

flags:

Optional flags (0, if there are none).

opt:

NEAT options (NULL, if there are none).

optcnt:

Number of NEAT options provided by "opt".

nsa_bindx() returns 0 in case of success, or -1 in case of error. The error code will be set in the errno variable. See the sctp_bindx() documentation for details.

nsa_bindn() nsa_bindn() binds a given NEAT socket to a given port. NEAT takes care of handling local addresses. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

port:

Port number to bind to.

flags:

Optional flags (0, if there are none).

opt:

NEAT options (NULL, if there are none).

optcnt:

Number of NEAT options provided by "opt".

nsa_bindn() returns 0 in case of success, or -1 in case of error. The error code will be set in the errno variable.

nsa_connect() nsa_connect() connects a given NEAT socket to a given remote address. Note: this function is provided as legacy wrapper, and it is RECOMMENDED to use nsa_connectn() instead. Note further, that nsa_connect() also supports a single address only (i.e. no multi-homing). nsa_connectx() SHOULD be used instead to support multi-homing. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

addr:

Address to connect to.

addrlen:

Length of the address structure "addr".

opt:

NEAT options (NULL, if there are none).

optcnt:

Number of NEAT options provided by "opt".

nsa_connect() returns 0 in case of success, or -1 in case of error. The error code will be set in the errno variable. See the connect() documentation for details.

nsa_connectx() nsa_connectx() connects a given NEAT socket to a given set of remote addresses. Note: this function is provided as legacy wrapper, and it is RECOMMENDED to use nsa_connectn() instead. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

addrs:

Addresses to connect to.

addrcnt:

Number of addresses in "addr".

id

Pointer to store association ID to (not used yet, use NULL!).

opt:

NEAT options (NULL, if there are none).

optcnt:

Number of NEAT options provided by "opt".

nsa_connectx() returns 0 in case of success, or -1 in case of error. The error code will be set in the errno variable. See the sctp_connectx() documentation for details.

nsa_connectn() nsa_connectn() connects a given NEAT socket to a given remote name and port. The remote name is resolved by NEAT to corresponding remote addresses. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

name:

Remote name to connect to.

port:

Remote port number to connect to.

id

Pointer to store association ID to (not used yet, use NULL!).

opt:

NEAT options (NULL, if there are none).

optcnt:

Number of NEAT options provided by "opt".

nsa_connectn() returns 0 in case of success, or -1 in case of error. The error code will be set in the errno variable.

nsa_listen() nsa_listen() marks a given NEAT socket as listening socket, i.e. accepting incoming connections. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

backlog:

Defines the maximum length to which the queue of pending connections for "sockfd" may grow.

nsa_listen() returns 0 in case of success, or -1 in case of error. The error code will be set in the errno variable. See the listen() documentation for details.

nsa_accept() nsa_accept() extracts the first connection request in the queue of pending connections for a listening NEAT socket, creates a new connected socket, and returns a new NEAT socket descriptor referring to that socket. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

addr:

Pointer to storage space to store the peer's primary address to (or NULL, if address is not needed).

addrlen:

Pointer to variable with size of the storage in "addr" (or NULL, if address is not needed).

nsa_accept() returns the new NEAT socket descriptor in case of success, or -1 in case of error. The error code will be set in the errno variable. In case of success, the peer's primary address is stored in "addr", if there is sufficient space. The variable pointer to by "addrlen" will then contain the actual address size. See the accept() documentation for details.

nsa_accept4() nsa_accept4() extracts the first connection request in the queue of pending connections for a listening NEAT socket, creates a new connected socket, and returns a new NEAT socket descriptor referring to that socket. If successful, and flags!=0, nsa_accept4() furthermore makes the new socket non-blocking (SOCK_NONBLOCK flag) and/or close-on-exec (SOCK_CLOEXEC flag). For flags==0, the behaviour is identical to nsa_accept(). Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

addr:

Pointer to storage space to store the peer's primary address to (or NULL, if address is not needed).

addrlen:

Pointer to variable with size of the storage in "addr" (or NULL, if address is not needed).

nsa_accept4() returns the new NEAT socket descriptor in case of success, or -1 in case of error. The error code will be set in the errno variable. In case of success, the peer's primary address is stored in "addr", if there is sufficient space. The variable pointer to by "addrlen" will then contain the actual address size. See the accept() documentation for details.

nsa_shutdown() nsa_shutdown() shuts down the connection of a given NEAT socket. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

how:

Not used for NEAT sockets (set to SHUT_RDWR).

nsa_shutdown() returns 0 in case of success, or -1 in case of error. The error code will be set in the errno variable. See the shutdown() documentation for details.

Options Handling

nsa_getsockopt() nsa_getsockopt() gets a socket option of a given NEAT socket. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

level:

Option level.

optname:

Option number.

optval:

Buffer to store option value to.

optlen:

Pointer to variable with length of the buffer in "optval".

nsa_getsockopt() returns 0 in case of success, or -1 in case of error. The error code will be set in the errno variable. See the getsockopt() documentation for details.

nsa_setsockopt() nsa_getsockopt() sets a socket option of a given NEAT socket. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

level:

Option level.

optname:

Option number.

optval:

Buffer with option value to set.

optlen:

Length of buffer with option value.

nsa_setsockopt() returns 0 in case of success, or -1 in case of error. The error code will be set in the errno variable. See the setsockopt() documentation for details.

nsa_opt_info() nsa_opt_info() gets a socket option of a given NEAT socket. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

id:

Association identifier (0 in case of 1:1-style sockets).

opt:

Option number.

arg:

Buffer to store option value to.

size:

Pointer to variable with length of the buffer in "arg".

nsa_opt_info() returns 0 in case of success, or -1 in case of error. The error code will be set in the errno variable. See the sctp_opt_info() documentation for details.

Security

nsa_set_secure_identity() TBD.

... TBD.

Input/Output Handling

nsa_write() nsa_write() sends data over a given connected NEAT socket. For NEAT sockets, nsa_write() is equal to nsa_send() with "flags" set to 0. Function Prototype: Arguments:

fd:

NEAT socket descriptor.

buf:

Data to send.

len:

Length of data to send.

nsa_write() returns the number of sent bytes in case of success, or -1 in case of error. The error code will be set in the errno variable. See the write() documentation for details.

nsa_writev() nsa_writev() sends data over a given connected NEAT socket. The data is provided by an iovec structure. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

iov:

Data to send provided as iovec structures.

iovcnt:

Number of provided iovec structures.

nsa_writev() returns the number of sent bytes in case of success, or -1 in case of error. The error code will be set in the errno variable. See the writev() documentation for details.

nsa_pwrite() nsa_pwrite() is a wrapper around the pwrite() call, using a NEAT socket descriptor instead. Function Prototype: See the pwrite() documentation for details.

nsa_pwrite64() nsa_pwrite64() is a wrapper around the pwrite64() call, using a NEAT socket descriptor instead. Function Prototype: See the pwrite64() documentation for details.

nsa_pwritev() nsa_pwritev() is a wrapper around the pwritev() call, using a NEAT socket descriptor instead. Function Prototype: See the pwritev() documentation for details.

nsa_pwritev64() nsa_pwritev64() is a wrapper around the pwritev64() call, using a NEAT socket descriptor instead. Function Prototype: See the pwritev64() documentation for details.

nsa_send() nsa_send() sends data over a given connected NEAT socket. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

buf:

Data to send.

len:

Length of data to send.

flags:

Optional flags (0, if there are none).

nsa_send() returns the number of sent bytes in case of success, or -1 in case of error. The error code will be set in the errno variable. See the send() documentation for details.

nsa_sendto() nsa_sendto() is a wrapper around the sendto() call, using NEAT socket descriptors instead. Note: this function is provided as legacy wrapper, and it is RECOMMENDED to use nsa_send() instead. On NEAT sockets, a provided destination address is ignored. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

buf:

Data to send.

len:

Length of data to send.

flags:

Optional flags (0, if there are none).

to:

Address to send data to (ignored for NEAT sockets).

tolen:

Length of address to send data to (ignored for NEAT sockets).

nsa_sendto() returns the number of sent bytes in case of success, or -1 in case of error. The error code will be set in the errno variable. See the send() documentation for details.

nsa_sendmsg() nsa_sendmsg() sends data over a given connected NEAT socket. The data and control information is provided by a msghdr structure. On NEAT sockets, a provided destination address is ignored. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

msg:

Data to send and corresponding control information as msghdr structure.

flags:

Optional flags (0, if there are none).

nsa_sendmsg() returns the number of sent bytes in case of success, or -1 in case of error. The error code will be set in the errno variable. See the sendmsg() documentation for details.

nsa_sendv() nsa_sendv() sends data over a given connected NEAT socket. The data and control information is provided by iovec and info structures. On NEAT sockets, a provided destination address is ignored. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

iov:

Data to send provided as iovec structures.

iovcnt:

Number of provided iovec structures.

to:

Address(es) to send data to (ignored for NEAT sockets).

tocnt:

Number of of addresses to send data to (ignored for NEAT sockets).

info:

Control information.

infolen:

Length of control information.

infotype:

Type of control information.

flags:

Optional flags (0, if there are none).

nsa_sendv() returns the number of sent bytes in case of success, or -1 in case of error. The error code will be set in the errno variable. See the sctp_sendv() documentation for details.

nsa_read() nsa_read() reads data from a given connected NEAT socket. For NEAT sockets, nsa_read() is equal to nsa_recv() with "flags" set to 0. Function Prototype: Arguments:

fd:

NEAT socket descriptor.

buf:

Buffer to store read data to.

len:

Length of the storage buffer.

nsa_read() returns the number of read bytes in case of success, 0 in case of connection shutdown, or -1 in case of error. The error code will be set in the errno variable. See the read() documentation for details.

nsa_readv() nsa_readv() reads data from a given connected NEAT socket. The data information buffers are provided by an iovec structure. Function Prototype: Arguments:

fd:

NEAT socket descriptor.

iov:

Data to send provided as iovec structures.

iovcnt:

Number of provided iovec structures.

nsa_readv() returns the number of read bytes in case of success, 0 in case of connection shutdown, or -1 in case of error. The error code will be set in the errno variable. See the readv() documentation for details.

nsa_pread() nsa_pread() is a wrapper around the pread() call, using a NEAT socket descriptor instead. Function Prototype: See the pread() documentation for details.

nsa_pread64() nsa_pread64() is a wrapper around the pread64() call, using a NEAT socket descriptor instead. Function Prototype: See the pread64() documentation for details.

nsa_preadv() nsa_preadv() is a wrapper around the preadv() call, using a NEAT socket descriptor instead. Function Prototype: See the preadv() documentation for details.

nsa_preadv64() nsa_preadv64() is a wrapper around the preadv64() call, using a NEAT socket descriptor instead. Function Prototype: See the preadv64() documentation for details.

nsa_recv() nsa_recv() reads data from a given connected NEAT socket. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

buf:

Buffer to store read data to.

len:

Length of the storage buffer.

flags:

Optional flags (0, if there are none).

nsa_recv() returns the number of read bytes in case of success, 0 in case of connection shutdown, or -1 in case of error. The error code will be set in the errno variable. See the recv() documentation for details.

nsa_recvfrom() nsa_recvfrom() reads data from a given connected NEAT socket. The peer's sending address of the data (if possible and useful for underlying transport protocol) is obtained as well. Note: this function is provided as legacy wrapper, and it is RECOMMENDED to use nsa_recv() instead. Function Prototype:

sockfd:

NEAT socket descriptor.

buf:

Buffer to store read data to.

len:

Length of the storage buffer.

flags:

Optional flags (0, if there are none).

from:

Pointer to storage space to store the peer's primary address to (or NULL, if address is not needed).

fromlen:

Pointer to variable with size of the storage in "from" (or NULL, if address is not needed).

nsa_recvfrom() returns the number of read bytes in case of success, 0 in case of connection shutdown, or -1 in case of error. The error code will be set in the errno variable. In case of success, the peer's sending address (if possible and useful for underlying transport protocol) may be stored in "from", if there is sufficient space. The variable pointer to by "fromlen" will then contain the actual address size. See the recvfrom() documentation for details.

nsa_recvmsg() nsa_recvmsg() reads data from a given connected NEAT socket. The data and control information buffers are provided by a msghdr structure. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

msg:

Data to send and corresponding control information as msghdr structure.

flags:

Optional flags (0, if there are none).

nsa_recvmsg() returns the number of read bytes in case of success, 0 in case of connection shutdown, or -1 in case of error. The error code will be set in the errno variable. See the recvmsg() documentation for details.

nsa_recvv() nsa_recvv() reads data from a given connected NEAT socket. The data and control information buffers are provided by iovec and info structures. Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

iov:

Data to send provided as iovec structures.

iovcnt:

Number of provided iovec structures.

from:

Pointer to storage space to store the peer's primary address to (or NULL, if address is not needed).

fromlen:

Pointer to variable with size of the storage in "from" (or NULL, if address is not needed).

info:

Pointer to storage space for control information.

infolen:

Pointer to variable with length of control information.

infotype:

Pointer to variable for storing the control information type to.

flags:

Pointer to variable with optional flags.

nsa_recvv() returns the number of sent received in case of success, or -1 in case of error. The error code will be set in the errno variable. See the sctp_recvv() documentation for details.

Poll and Select

nsa_poll() nsa_poll() waits for activity (input/output/error/...) on a set of given NEAT sockets. Function Prototype: Arguments:

ufds:

NEAT socket descriptor and requested activity for each NEAT socket.

nfds:

Number of sockets given by "ufds".

timeout:

Timeout in milliseconds.

nsa_poll() returns the number of NEAT sockets with activity in case of success, 0 in case of timeout, or -1 in case of error. The error code will be set in the errno variable. See the poll() documentation for details.

nsa_select() nsa_select() is a wrapper around the select() call, using NEAT socket descriptors instead. Note: this function is provided as legacy wrapper, and it is RECOMMENDED to use nsa_poll() instead. Function Prototype: See the select() documentation for details.

Address Handling

nsa_getsockname() nsa_getsockname() obtains the first local address of a socket. Note: this function is provided as legacy wrapper, and it is RECOMMENDED to use nsa_getladdrs() instead to support multi-homed transport protocols! Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

name:

Storage space for the address.

namelen:

Pointer to variable with the storage space's size.

Return Value: nsa_getsockname() returns 0 in case of success (with the actual address size stored into the "namelen" variable), or -1 in case of error. The error code will be set in the errno variable. See the getsockname() documentation for details.

nsa_getpeername() nsa_getpeername() obtains the first remote address of a connected socket. Note: this function is provided as legacy wrapper, and it is RECOMMENDED to use nsa_getpaddrs() instead to support multi-homed transport protocols! Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

name:

Storage space for the address.

namelen:

Pointer to variable with the storage space's size.

Return Value: nsa_getpeername() returns 0 in case of success (with the actual address size stored into the "namelen" variable), or -1 in case of error. The error code will be set in the errno variable. See the getpeername() documentation for details.

nsa_getladdrs() nsa_getladdrs() obtains the local addresses of a socket. The storage space for the addresses will be automatically allocated and needs to be freed by nsa_freeladdrs(). Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

id:

Association identifier (0 in case of 1:1-style sockets).

addrs:

Pointer to variable to store pointer to addresses to.

nsa_getladdrs() returns the number of addresses stored into a newly allocated space. The pointer to this space is stored into the variable provided by "addrs". In case of error, -1 is returned, and the error code will be set in the errno variable.

nsa_freeladdrs() nsa_freeladdrs() frees addresses obtained by nsa_getladdrs(). Function Prototype: Arguments:

addrs:

Pointer to addresses to be freed.

nsa_getpaddrs() nsa_getpaddrs() obtains the remote addresses of a connected socket. The storage space for the addresses will be automatically allocated and needs to be freed by nsa_freepaddrs(). Function Prototype: Arguments:

sockfd:

NEAT socket descriptor.

id:

Association identifier (0 in case of 1:1-style sockets).

addrs:

Pointer to variable to store pointer to addresses to.

nsa_getpaddrs() returns the number of addresses stored into a newly allocated space. The pointer to this space is stored into the variable provided by "addrs". In case of error, -1 is returned, and the error code will be set in the errno variable.

nsa_freepaddrs() nsa_freepaddrs() frees addresses obtained by nsa_getpaddrs(). Function Prototype: Arguments:

addrs:

Pointer to addresses to be freed.

Miscellaneous This section contains miscellaneous wrapper functions, mostly around file I/O. Since Unix file descriptors are used together with socket descriptors in functions like poll(), select(), etc., it is necessary to wrap functions handling file descriptors as well.

nsa_open() nsa_open() is a wrapper around the open() call, returning a NEAT socket descriptor instead. Function Prototype: See the open() documentation for details.

nsa_creat() nsa_creat() is a wrapper around the creat() call, returning a NEAT socket descriptor instead. Function Prototype: See the creat() documentation for details.

nsa_lockf() nsa_lockf() is a wrapper around the lockf() call, using a NEAT socket descriptor instead. Function Prototype: See the lockf() documentation for details.

nsa_lockf64() nsa_lockf64() is a wrapper around the lockf64() call, using a NEAT socket descriptor instead. Function Prototype: See the lockf64() documentation for details.

nsa_flock() nsa_flock() is a wrapper around the flock() call, using a NEAT socket descriptor instead. Function Prototype: See the flock() documentation for details.

nsa_fstat() nsa_fstat() is a wrapper around the fstat() call, using a NEAT socket descriptor instead. Function Prototype: See the fstat() documentation for details.

nsa_fpathconf() nsa_fpathconf() is a wrapper around the fpathconf() call, using a NEAT socket descriptor instead. Function Prototype: See the fpathconf() documentation for details.

nsa_fchown() nsa_fchown() is a wrapper around the fchown() call, using a NEAT socket descriptor instead. Function Prototype: See the fchown() documentation for details.

nsa_fsync() nsa_fsync() is a wrapper around the fsync() call, using a NEAT socket descriptor instead. Function Prototype: See the fsync() documentation for details.

nsa_fdatasync() nsa_fdatasync() is a wrapper around the fdatasync() call, using a NEAT socket descriptor instead. Function Prototype: See the fdatasync() documentation for details.

nsa_syncfs() nsa_syncfs() is a wrapper around the syncfs() call, using a NEAT socket descriptor instead. Function Prototype: See the syncfs() documentation for details.

nsa_dup2() nsa_dup2() is a wrapper around the dup2() call, using a NEAT socket descriptor instead. Function Prototype: See the dup2() documentation for details.

nsa_dup3() nsa_dup3() is a wrapper around the dup3() call, using a NEAT socket descriptor instead. Function Prototype: See the dup3() documentation for details.

nsa_dup() nsa_dup() is a wrapper around the dup() call, using a NEAT socket descriptor instead. Function Prototype: See the dup() documentation for details.

nsa_lseek() nsa_lseek() is a wrapper around the lseek() call, using a NEAT socket descriptor instead. Function Prototype: See the lseek() documentation for details.

nsa_lseek64() nsa_lseek64() is a wrapper around the lseek64() call, using a NEAT socket descriptor instead. Function Prototype: See the lseek64() documentation for details.

nsa_truncate() nsa_truncate() is a wrapper around the truncate() call, using a NEAT socket descriptor instead. Function Prototype: See the truncate() documentation for details.

nsa_truncate64() nsa_truncate64() is a wrapper around the truncate64() call, using a NEAT socket descriptor instead. Function Prototype: See the truncate64() documentation for details.

nsa_pipe() nsa_pipe() is a wrapper around the pipe() call, returning NEAT socket descriptors instead. Function Prototype: See the pipe() documentation for details.

nsa_ioctl() nsa_ioctl() is a wrapper around the ioctl() call, using a NEAT socket descriptor instead. Function Prototype: See the ioctl() documentation for details.

Code Examples Running code examples can be found in the NEAT Git repository, with some tutorial material in , :

URL: https://github.com/NEAT-project/neat

Branch: dreibh/neat-socketapi

Directory: socketapi/examples/

Testbed Platform A large-scale and realistic Internet testbed platform with support for the multi-homing feature of the underlying SCTP and MPTCP protocols is NorNet. A description of NorNet is provided in , , some further information can be found on the project website .

Security Considerations Security considerations for the SCTP sockets API are described in .

IANA Considerations This document does not require IANA actions.

Acknowledgments This work was partially funded by the European Union's Horizon 2020 research and innovation programme under grant agreement No. 644334 (NEAT). The views expressed are solely those of the author(s). The author would like to thank David Ros, Michael Welzl, and Xing Zhou for their support.

References Normative References In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. This document describes a mapping of the Stream Control Transmission Protocol (SCTP) into a sockets API. The benefits of this mapping include compatibility for TCP applications, access to new SCTP features, and a consolidated error and event notification scheme. This document is not an Internet Standards Track specification; it is published for informational purposes. University of Oslo University of Oslo This draft recommends a minimal set of IETF Transport Services offered by end systems supporting TAPS, and gives guidance on choosing among the available mechanisms and protocols. It is based on the set of transport features given in the TAPS document draft-ietf-taps-transports-usage-05. University of Oslo Muenster University of Applied Sciences University of Oslo This document describes how the transport protocols Transmission Control Protocol (TCP), MultiPath TCP (MPTCP), Stream Control Transmission Protocol (SCTP), User Datagram Protocol (UDP), and Lightweight User Datagram Protocol (UDP-Lite) expose services to applications and how an application can configure and use the features that make up these services. It also discusses the service provided by the Low Extra Delay Background Transport (LEDBAT) congestion control mechanism. The description results in a set of transport abstractions that can be exported in a transport services (TAPS) API. Informative References