Ok, da' tot e pe linga subiect referinta la dns.
inet_itoa/inet_atoi sint functii de conversie intre formatul numeric
(ala valabil in transmisiile de date, adica primul bit e cel mai
semnificativ) si sir de caractere.
Comportamentul acestor functii are o explicatie. Cum orice adresa IP
valida trebuie sa inceapa cu un octet nenul, se citeste primul octet in
prima pozitie. Ceilalti 3 octeti insa, se citesc conform unui algoritm
de genul:
read first_octet;
ip = 0;
while ( numarul de octeti deja cititi < 4 && read x)
ip = (ip << 8) + x;
ip |= first_octet << 24;
Probabil in vremea ARPANET-ului, spatiul de adresare IP se considera a
fi imens, de aceea inginerii de atunci au cautat sa scurteze formatul
adreselor de gen a.0.0.b sau a.0.b.c, tot asa cum inginerii din zilele
noastre au inventat formatul scurt al adreselor IPv6.
Mihai RUSU wrote:
>Simplu:
>
>$ cat strangeip.c
>#include <stdio.h>
>#include <sys/socket.h>
>#include <netinet/in.h>
>#include <arpa/inet.h>
>
>int main(int argc, char ** argv)
>{
> struct in_addr addr;
>
> if (argc != 2) {
> printf("Syntax: %s <ip>\n", argv[0]);
> return -1;
> }
>
> inet_aton(argv[1], &addr);
> printf("%s - %s\n", argv[1], inet_ntoa(addr));
>
> return 0;
>}
>
>$ gcc strangeip.c -o strangeip
>
>$ ./strangeip 1.2.3.4
>1.2.3.4 - 1.2.3.4
>
>$ ./strangeip 1.2
>1.2 - 1.0.0.2
>
>On Wed, 14 Apr 2004, George Cristian Birzan wrote:
>
>
>
>>On Wed, Apr 14, 2004 at 05:28:17PM +0300, Dan Uscatu wrote:
>>
>>
>>>$ /usr/sbin/traceroute 18.1.11
>>>traceroute to 18.1.11 (18.1.0.11), 30 hops max, 38 byte packets
>>>
>>>comportament similar si la mtr si ping, dar nu si la host.
>>>
>>>wtf ?
>>>
>>>
>>Ce legatura are asta cu DNS-ul?
>>Ia da ping 2130706433 . ping 0x0A.1 . ping 0xB0.0x10.1 .
>>Incepi sa intelegi? Incearca 192.168.0.07, dupa care intreaba-l pe
>>petre cum a aflat el de chestia asta. :-)
>>
>>--
>>George Cristian Birzan gcbirzan (at) wolfheart (dot) ro
>>The power of accurate observation is frequently called cynicism by
>>those who don't have it.
>> -- George Bernard Shaw
>>
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