1tcp_RegCatchall(3z)        z88dk Programmer's Manual       tcp_RegCatchall(3z)
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NAME

6       tcp_RegCatchall - (De)register packet catcher
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SYNOPSIS

9       #include <net/misc.h>
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11       int tcp_RegCatchall(int libcall);
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DESCRIPTION

14       The tcp_RegCatchall() function registers or deregisters a function that
15       is used to catch all incoming packets after it  has  passed  the  basic
16       tests of checksumming, length and ttl-checking.  l-checking.
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18       The  parameter libcall is the ID for a shared library/packet call which
19       has the prototype thus:
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21       bool_t Function(void *dp, size_t len);
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23       Where dp is the address of the packet and len  is  the  length  of  the
24       packet. This function should return TRUE/FALSE to indicate to the ZSock
25       kernel whether the function has dealt with the packet and ZSock  should
26       not process it.
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RETURN VALUE

30       tcp_RegCatchall() returns the previous ID of the catchall function.
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NOTES

34       Should  you wish to stop calling your catchall function simply call the
35       function with an argument of NULL.
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37       This function is of use should somebody write a driver for  an  as  yet
38       unsupported protocol.
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40       The  package call should page in the ZSock data area using the function
41       tcp_pagein(3z).
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43       This call could for example be used to  implement  a  traceroute  style
44       routine  to  catch ICMP replies. Returning TRUE when it has received an
45       ICMP reply packet of the correct tyoe, and FALSE otherwise.
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SEE ALSO

50       tcp_pagein(3z), tcp_pageout(3z)
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AUTHOR

54       Dominic Morris <dom@jb.man.ac.uk>
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59                               18 February 2000            tcp_RegCatchall(3z)