INT 61 - PC/TCP kernel v2.05 - "net_connect" - OPEN A NETWORK CONNECTION
        AH = 13h
        BX = network descriptor (FFFFh for automatic net_getdesc)
        DX = protocol (see below)
        DS:SI -> buffer for "addr" structure (see below)
Return: CF clear if successful
            AX = network descriptor used or allocated
        CF set on error
            AX = error code (see INT 61"PC/TCP")
Notes:  invokes AH=22h if BX=FFFFh on entry; also invokes AH=19h in various
          cases
        will wait for protocol on stream connections unless non-blocking was
          set with AH=20h
SeeAlso: INT 61"PC/TCP",INT 61/AH=00h"PC/TCP",INT 61/AH=18h,INT 61/AH=23h
SeeAlso: INT 63/AH=14h"BW-TCP"

Values for protocol:
 0001h  raw net (undocumented)
 0002h  raw IP
 0003h  datagram (UDP)
 0004h  stream (TCP)
 0005h  raw ICMP

Format of structure "addr":
Offset  Size    Description
 00h    DWORD   Internet address (network order)
 04h    WORD    remote socket number (network order)
 06h    WORD    local socket number (network order) 0000h means "you choose"
 08h    BYTE    protocol (see above)

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