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Shardik
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PostPosted: Thu Apr 26, 2007 10:30 am     Reply with quote
I need to compare two ip address, this is my code:

typedef struct {
int v[4];
} ip_addr;

And the problem:

ip_addr ip1=192,168,6,5;
ip_addr ip2=192,168,6,5;

How can i compare this two ip?

ip1==ip2 doesnt work, and ip must be a ip_addr type, what can i do? with pointers?
frequentguest
Guest
PostPosted: Thu Apr 26, 2007 10:59 am     Reply with quote
A good way to deal with IP addresses is to use a union.
Code:
typedef union
{
   int8   bytes[4];
   int32 ip
} ip_addr;


This way you can easily deal with the IP address byte-wise or as a whole.

Code:
ip_addr ip1;

ip1.bytes[0]=255;
ip1.ip=0xFFFFFFFF;
[/code]
treitmey



Joined: 23 Jan 2004
Posts: 1094
Location: Appleton,WI USA

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PostPosted: Thu Apr 26, 2007 11:04 am     Reply with quote
yup
Code:
#include <16F877.h>
#use delay(clock=4000000)
#fuses HS,NOWDT,NOLVP
#use rs232(baud=19200,xmit=PIN_C0,invert,stream=DEBUG,disable_ints) // stderr(same as debug)
#use fast_io (a)
  union ip_def
  {
    int8 oct[4];
    int32 combined;
  };

  union ip_def ip_i;
  union ip_def ip_o;
//======================= Main ==============================
void main(void)
{

  ip_i.oct[0]=255;
  ip_i.oct[1]=255;
  ip_i.oct[2]=255;
  ip_i.oct[3]=255;
 
  ip_o.oct[0]=255;
  ip_o.oct[1]=255;
  ip_o.oct[2]=255;
  ip_o.oct[3]=1;

  tris_a=0xFF;
  setup_adc_ports(NO_ANALOGS);
  setup_adc(ADC_OFF);
  if(ip_i.combined != ip_o.combine) fprintf(DEBUG,"nope\n\r");
  while(1)
  {
  }
}
Shardik
Guest
Thx
PostPosted: Thu Apr 26, 2007 3:41 pm     Reply with quote
Thxs a lot for the replys, it really help me, but im still having some problems:


Code:

typedef union{
int8 v[4];
int32 combined;
} ip_addr;


typedef struct {
mac_addr mac;
ip_addr ip;
} arp_table;

arp_table tabla;
ip_addr sr;

tabla.ip=192,168,8,3;

sr=192,168,8,3;

if(tabla.ip.combined==sr.combined) printf(lcd_putc,"YES");
else printf(lcd_putc,"NO");


Nevers says YES!!! Do you know where is the problem?
Shardik
Guest
PostPosted: Thu Apr 26, 2007 3:48 pm     Reply with quote
And how can i do with mac address? (6byte addres)

union ip{
int8 v[4];
int32 combined;
}

union mac{
int8 v[6]:
??? combined;
}
frequentguest
Guest
PostPosted: Thu Apr 26, 2007 3:58 pm     Reply with quote
The purpose of the union is that you can treat the ip address as either a 32-bit int or as 4 individual bytes. I imagine the compiler doesn't know what to do with these lines:
Quote:
Code:
tabla.ip=192,168,8,3;

sr=192,168,8,3;


you can use:
Code:

tabla.ip.v[0]=192;
tabla.ip.v[1]=168;
tabla.ip.v[2]=8;
tabla.ip.v[3]=3;

//or easier yet
tabla.ip.combined=0xC0A80803;

and then do your comparison
frequentguest
Guest
PostPosted: Thu Apr 26, 2007 3:59 pm     Reply with quote
as for the mac address issue, since the compiler can't handle a 48-bit variable, look at the memcpy() function of the compiler.
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