TUNABLE

The following parameters should be tunable at compile time. Some of them
exist as sysctls too.

This is far from complete

Item			Description
----------------------------------------------------------------------------
MAX_LINKS		Maximum number of netlink minor devices. (1-32)
RIF_TABLE_SIZE		Token ring RIF cache size (tunable)
AARP_HASH_SIZE		Size of Appletalk hash table (tunable)
AX25_DEF_T1		AX.25 parameters. These are all tunable via
AX25_DEF_T2		SIOCAX25SETPARMS
AX25_DEF_T3		T1-T3,N2 have the meanings in the specification
AX25_DEF_N2
AX25_DEF_AXDEFMODE	8 = normal 128 is PE1CHL extended
AX25_DEF_IPDEFMODE	'D' - datagram  'V' - virtual connection
AX25_DEF_BACKOFF	'E'xponential 'L'inear
AX25_DEF_NETROM		Allow netrom 1=Y
AX25_DF_TEXT		Allow PID=Text 1=Y
AX25_DEF_WINDOW		Window for normal mode
AX25_DEF_EWINDOW	Window for PE1CHL mode
AX25_DEF_DIGI		1 for inband 2 for cross band 3 for both
AX25_DEF_CONMODE	Allow connected modes 1=Yes
AX25_ROUTE_MAX		AX.25 route cache size - no currently tunable
Unnamed (16)		Number of protocol hash slots (tunable)
DEV_NUMBUFFS		Number of priority levels (not easily tunable)
Unnamed (300)		Maximum packet backlog queue (tunable)
MAX_IOVEC		Maximum number of iovecs in a message (tunable)
MIN_WINDOW		Offered minimum window (tunable)
MAX_WINDOW		Offered maximum window (tunable)
MAX_HEADER		Largest physical header (tunable)
MAX_ADDR_LEN		Largest physical address (tunable)
SOCK_ARRAY_SIZE		IP socket array hash size (tunable)
IP_MAX_MEMBERSHIPS	Largest number of groups per socket (BSD style) (tunable)
16			Hard coded constant for amount of room allowed for
			cache align and faster forwarding (tunable)
IP_FRAG_TIME		Time we hold a fragment for. (tunable)
PORT_MASQ_BEGIN		First port reserved for masquerade (tunable)
PORT_MASQ_END		Last port used for masquerade	(tunable)
MASQUERADE_EXPIRE_TCP_FIN	Time we keep a masquerade for after a FIN
MASQUERADE_EXPIRE_UDP	Time we keep a UDP masquerade for (tunable)
MAXVIFS			Maximum mrouted vifs (1-32)
MFC_LINES		Lines in the multicast router cache (tunable)

NetROM parameters are tunable via an ioctl passing a struct

4000			Size a Unix domain socket malloc falls back to 
			(tunable) should be 8K - a bit for 8K machines like
			the ALPHA