tcp.h File Reference

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Detailed Description

TCP protocol definitions.

Defines
#define	TH_FIN   0x01
	Finishing transmission.
#define	TH_SYN   0x02
	Synchronizing sequence numbers.
#define	TH_RST   0x04
	Reset connection.
#define	TH_PUSH   0x08
	Push data to application level.
#define	TH_ACK   0x10
	Acknowledge field is valid.
#define	TH_URG   0x20
	Urgent data present.
#define	TH_FLAGS   (TH_FIN | TH_SYN | TH_RST | TH_ACK | TH_URG)
	TCP flag mask.
#define	TCPOPT_EOL   0
	End of options.
#define	TCPOPT_NOP   1
	Nothing.
#define	TCPOPT_MAXSEG   2
	Maximum segment size.
#define	TCPOLEN_MAXSEG   4
	Maximum segment size length.
#define	TCPOPT_WINDOW   3
	Receive window.
#define	TCPOLEN_WINDOW   3
	Receive window length.
#define	TCP_MSS   536
	Default maximum segment size.
#define	TCP_WINSIZE   3216
	Default window size.
#define	TCP_MAXWIN   65535
	Largest value for (unscaled) window.
#define	TTCP_CLIENT_SND_WND   4096
	Default send window for T/TCP client.
#define	TCP_MAX_WINSHIFT   14
	Maximum window shift.
#define	TCP_MAXHLEN   (0xf<<2)
	Maximum length of header in bytes.
#define	TCP_MAXOLEN   (TCP_MAXHLEN - sizeof(struct tcphdr))
	Maximum space left for options.
#define	TCP_NODELAY   0x01
	Don't delay send to coalesce segments.
#define	TCP_MAXSEG   0x02
	Set maximum segment size.
#define	TCP_NOPUSH   0x04
	Don't push last block of write.
#define	TCP_NOOPT   0x08
	Don't use TCP options.
Typedefs
typedef tcphdr	TCPHDR
	TCP protocol header type.
typedef _TCPPSEUDOHDR	TCPPSEUDOHDR
	TCP pseudo header type.

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Define Documentation

#define TCP_MSS   536

Default maximum segment size. The maximum size of an IP datagram, that will not become fragmented, is 576. The maximum IP datagram for Ethernet is 1500. Reduce this number by 40, 20 bytes TCP header and 20 bytes IP header.

#define TCP_WINSIZE   3216

Default window size. It's recommended to set this 6 times the maximum segment size.

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