Source code of all these network functions is available from a number of
sites on the internet and there is nothing magic about it. I am
copying BSD source code for inet_aton(). You can look for other
functions at the following web site:
http://www.ajk.tele.fi/libc/code.html
/* */
/* inet_aton */
int
inet_aton(cp, addr)
register const char *cp;
struct in_addr *addr;
{
register u_long val;
register int base, n;
register char c;
u_int parts[4];
register u_int *pp = parts;
c = *cp;
for (;;) {
/*
* Collect number up to ``.''.
* Values are specified as for C:
* 0x=hex, 0=octal, isdigit=decimal.
*/
if (!isdigit(c))
return (0);
val = 0; base = 10;
if (c == '0') {
c = *++cp;
if (c == 'x' || c == 'X')
base = 16, c = *++cp;
else
base = 8;
}
for (;;) {
if (isascii(c) && isdigit(c)) {
val = (val * base) + (c - '0');
c = *++cp;
} else if (base == 16 && isascii(c) && isxdigit(c)) {
val = (val << 4) |
(c + 10 - (islower(c) ? 'a' : 'A'));
c = *++cp;
} else
break;
}
if (c == '.') {
/*
* Internet format:
* a.b.c.d
* a.b.c (with c treated as 16 bits)
* a.b (with b treated as 24 bits)
*/
if (pp >= parts + 3)
return (0);
*pp++ = val;
c = *++cp;
} else
break;
}
/*
* Check for trailing characters.
*/
if (c != '\0' && (!isascii(c) || !isspace(c)))
return (0);
/*
* Concoct the address according to
* the number of parts specified.
*/
n = pp - parts + 1;
switch (n) {
case 0:
return (0); /* initial nondigit */
case 1: /* a -- 32 bits */
break;
case 2: /* a.b -- 8.24 bits */
if (val > 0xffffff)
return (0);
val |= parts[0] << 24;
break;
case 3: /* a.b.c -- 8.8.16 bits */
if (val > 0xffff)
return (0);
val |= (parts[0] << 24) | (parts[1] << 16);
break;
case 4: /* a.b.c.d -- 8.8.8.8 bits */
if (val > 0xff)
return (0);
val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
break;
}
if (addr)
addr->s_addr = htonl(val);
return (1);
}
------------------------------------------------------------------
Rafeeq Ur Rehman
http://vig.prenhall.com/academic/product/1,3411,0130183741,00.html
------------------------------------------------------------------
----- Original Message -----
From: Randolph Lee
To: [EMAIL PROTECTED]
Sent: Monday, December 04, 2000 12:05 AM
Subject: [rtl] rtnet
Hello,
Currently I'm working on a project using RT Linux for networking. I'm using
Rtnet V0.9.0. I was wondering if there is an RT function that is similar to
inet_addr or inet_aton (in arpa/inet.h).
Thanks,
Randolph
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