Sockets

Overview

Macros
#define	LWIP_SOCKET   1
#define	LWIP_COMPAT_SOCKETS   1
#define	LWIP_POSIX_SOCKETS_IO_NAMES   1
#define	LWIP_SOCKET_OFFSET   0
#define	LWIP_TCP_KEEPALIVE   0
#define	LWIP_SO_SNDTIMEO   0
#define	LWIP_SO_RCVTIMEO   0
#define	LWIP_TCP_USER_TIMEOUT   0
#define	LWIP_SO_SNDRCVTIMEO_NONSTANDARD   0
#define	LWIP_SO_RCVBUF   0
#define	LWIP_SIOCOUTQ   0
#define	LWIP_SO_LINGER   0
#define	RECV_BUFSIZE_DEFAULT   INT_MAX
#define	LWIP_TCP_CLOSE_TIMEOUT_MS_DEFAULT   20000
#define	SO_REUSE   0
#define	SO_REUSE_RXTOALL   0
#define	LWIP_FIONREAD_LINUXMODE   0
#define	LWIP_SOCKET_SELECT   1
#define	LWIP_SOCKET_POLL   1

Macro Definition Documentation

#define LWIP_SOCKET   1

LWIP_SOCKET==1: Enable Socket API (require to use sockets.c)

#define LWIP_COMPAT_SOCKETS   1

LWIP_COMPAT_SOCKETS==1: Enable BSD-style sockets functions names through defines. LWIP_COMPAT_SOCKETS==2: Same as ==1 but correctly named functions are created. While this helps code completion, it might conflict with existing libraries. (only used if you use sockets.c)

#define LWIP_POSIX_SOCKETS_IO_NAMES   1

LWIP_POSIX_SOCKETS_IO_NAMES==1: Enable POSIX-style sockets functions names. Disable this option if you use a POSIX operating system that uses the same names (read, write & close). (only used if you use sockets.c)

#define LWIP_SOCKET_OFFSET   0

LWIP_SOCKET_OFFSET==n: Increases the file descriptor number created by LwIP with n. This can be useful when there are multiple APIs which create file descriptors. When they all start with a different offset and you won't make them overlap you can re implement read/write/close/ioctl/fnctl to send the requested action to the right library (sharing select will need more work though).

#define LWIP_TCP_KEEPALIVE   0

LWIP_TCP_KEEPALIVE==1: Enable TCP_KEEPIDLE, TCP_KEEPINTVL and TCP_KEEPCNT options processing. Note that TCP_KEEPIDLE and TCP_KEEPINTVL have to be set in seconds. (does not require sockets.c, and will affect tcp.c)

#define LWIP_SO_SNDTIMEO   0

LWIP_SO_SNDTIMEO==1: Enable send timeout for sockets/netconns and SO_SNDTIMEO processing.

#define LWIP_SO_RCVTIMEO   0

LWIP_SO_RCVTIMEO==1: Enable receive timeout for sockets/netconns and SO_RCVTIMEO processing.

#define LWIP_TCP_USER_TIMEOUT   0

LWIP_TCP_USER_TIMEOUT==1: Enable socket send timeout. It specifies the maximum amount of time in milliseconds that transmitted data may remain unacknowledged before TCP will forcibly close.

#define LWIP_SO_SNDRCVTIMEO_NONSTANDARD   0

LWIP_SO_SNDRCVTIMEO_NONSTANDARD==1: SO_RCVTIMEO/SO_SNDTIMEO take an int (milliseconds, much like winsock does) instead of a struct timeval (default).

#define LWIP_SO_RCVBUF   0

LWIP_SO_RCVBUF==1: Enable SO_RCVBUF processing.

#define LWIP_SIOCOUTQ   0

LWIP_SIOCOUTQ==1: Enable LWIP_SIOCOUTQ reading. It returns count of (not sent + not acked) data bytes in send buffer.

#define LWIP_SO_LINGER   0

LWIP_SO_LINGER==1: Enable SO_LINGER processing.

#define RECV_BUFSIZE_DEFAULT   INT_MAX

If LWIP_SO_RCVBUF is used, this is the default value for recv_bufsize.

#define LWIP_TCP_CLOSE_TIMEOUT_MS_DEFAULT   20000

By default, TCP socket/netconn close waits 20 seconds max to send the FIN

#define SO_REUSE   0

SO_REUSE==1: Enable SO_REUSEADDR option.

#define SO_REUSE_RXTOALL   0

SO_REUSE_RXTOALL==1: Pass a copy of incoming broadcast/multicast packets to all local matches if SO_REUSEADDR is turned on. WARNING: Adds a memcpy for every packet if passing to more than one pcb!

#define LWIP_FIONREAD_LINUXMODE   0

LWIP_FIONREAD_LINUXMODE==0 (default): ioctl/FIONREAD returns the amount of pending data in the network buffer. This is the way windows does it. It's the default for lwIP since it is smaller. LWIP_FIONREAD_LINUXMODE==1: ioctl/FIONREAD returns the size of the next pending datagram in bytes. This is the way linux does it. This code is only here for compatibility.

#define LWIP_SOCKET_SELECT   1

LWIP_SOCKET_SELECT==1 (default): enable select() for sockets (uses a netconn callback to keep track of events). This saves RAM (counters per socket) and code (netconn event callback), which should improve performance a bit).

#define LWIP_SOCKET_POLL   1

LWIP_SOCKET_POLL==1 (default): enable poll() for sockets (including struct pollfd, nfds_t, and constants)