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ARM Club 3
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TheARMClub_PDCD3.iso
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hensa
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network
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netlib_1
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NetLibSrc
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c
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netof
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1995-02-28
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602b
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34 lines
#include "arpa/inet.h"
#include "netinet/in.h"
/*
* Extract a network number from an internet address
*/
u_long inet_netof(struct in_addr in)
{
u_long net;
if (IN_CLASSA(in.s_addr))
{
/* Extract a class A network number */
net = in.s_addr & IN_CLASSA_NET;
}
else if (IN_CLASSB(in.s_addr))
{
/* Extract a class B network number */
net = in.s_addr & IN_CLASSB_NET;
}
else if (IN_CLASSC(in.s_addr))
{
/* Extract a class C network number */
net = in.s_addr & IN_CLASSC_NET;
}
else
{
/* Not a known address format */
net = 0;
}
return net;
}