bgp_ecommunity.c

大名鼎鼎的路由器源码。程序分ZEBRA、OSPFRIP等3个包。程序框架采用一个路由协议一个进程的方式

	    }
	  goto error;
	}
      goto error;
    }
  
  while (isdigit ((int) *p) || *p == ':' || *p == '.') 
    {
      if (*p == ':') 
	{
	  if (separator)
	    goto error;

	  separator = 1;
	  digit = 0;

	  if (dot)
	    {
	      if ((p - str) > INET_ADDRSTRLEN)
		goto error;

	      memset (ipstr, 0, INET_ADDRSTRLEN + 1);
	      memcpy (ipstr, str, p - str);

	      ret = inet_aton (ipstr, &ip);
	      if (ret == 0)
		goto error;
	    }
	  else
	    val_high = val_low;

	  val_low = 0;
	}
      else if (*p == '.')
	{
	  if (separator)
	    goto error;
	  dot++;
	  if (dot > 4)
	    goto error;
	}
      else
	{
	  digit = 1;
	  val_low *= 10;
	  val_low += (*p - '0');
	}
      p++;
    }

  /* Low digit part must be there. */
  if (! digit || ! separator)
    goto error;

  /* Encode result into routing distinguisher.  */
  if (dot)
    {
      eval->val[0] = ECOMMUNITY_ENCODE_IP;
      eval->val[1] = 0;
      memcpy (&eval->val[2], &ip, sizeof (struct in_addr));
      eval->val[6] = (val_low >> 8) & 0xff;
      eval->val[7] = val_low & 0xff;
    }
  else
    {
      eval->val[0] = ECOMMUNITY_ENCODE_AS;
      eval->val[1] = 0;
      eval->val[2] = (val_high >>8) & 0xff;
      eval->val[3] = val_high & 0xff;
      eval->val[4] = (val_low >>24) & 0xff;
      eval->val[5] = (val_low >>16) & 0xff;
      eval->val[6] = (val_low >>8) & 0xff;
      eval->val[7] = val_low & 0xff;
    }
  *token = ecommunity_token_val;
  return p;

 error:
  *token = ecommunity_token_unknown;
  return p;
}

/* Convert string to extended community attribute. 

   When type is already known, please specify both str and type.  str
   should not include keyword such as "rt" and "soo".  Type is
   ECOMMUNITY_ROUTE_TARGET or ECOMMUNITY_SITE_ORIGIN.
   keyword_included should be zero.

   For example route-map's "set extcommunity" command case:

   "rt 100:1 100:2 100:3"        -> str = "100:1 100:2 100:3"
                                    type = ECOMMUNITY_ROUTE_TARGET
                                    keyword_included = 0

   "soo 100:1"                   -> str = "100:1"
                                    type = ECOMMUNITY_SITE_ORIGIN
                                    keyword_included = 0

   When string includes keyword for each extended community value.
   Please specify keyword_included as non-zero value.

   For example standard extcommunity-list case:

   "rt 100:1 rt 100:2 soo 100:1" -> str = "rt 100:1 rt 100:2 soo 100:1"
                                    type = 0
                                    keyword_include = 1
*/
struct ecommunity *
ecommunity_str2com (char *str, int type, int keyword_included)
{
  struct ecommunity *ecom = NULL;
  enum ecommunity_token token;
  struct ecommunity_val eval;
  int keyword = 0;

  while ((str = ecommunity_gettoken (str, &eval, &token)))
    {
      switch (token)
	{
	case ecommunity_token_rt:
	case ecommunity_token_soo:
	  if (! keyword_included || keyword)
	    {
	      if (ecom)
		ecommunity_free (ecom);
	      return NULL;
	    }
	  keyword = 1;

	  if (token == ecommunity_token_rt)
	    {
	      type = ECOMMUNITY_ROUTE_TARGET;
	    }
	  if (token == ecommunity_token_soo)
	    {
	      type = ECOMMUNITY_SITE_ORIGIN;
	    }
	  break;
	case ecommunity_token_val:
	  if (keyword_included)
	    {
	      if (! keyword)
		{
		  if (ecom)
		    ecommunity_free (ecom);
		  return NULL;
		}
	      keyword = 0;
	    }
	  if (ecom == NULL)
	    ecom = ecommunity_new ();
	  eval.val[1] = type;
	  ecommunity_add_val (ecom, &eval);
	  break;
	case ecommunity_token_unknown:
	default:
	  if (ecom)
	    ecommunity_free (ecom);
	  return NULL;
	  break;
	}
    }
  return ecom;
}

/* Convert extended community attribute to string.  

   Due to historical reason of industry standard implementation, there
   are three types of format.

   route-map set extcommunity format
        "rt 100:1 100:2"
        "soo 100:3"

   extcommunity-list
        "rt 100:1 rt 100:2 soo 100:3"

   "show ip bgp" and extcommunity-list regular expression matching
        "RT:100:1 RT:100:2 SoO:100:3"

   For each formath please use below definition for format:

   ECOMMUNITY_FORMAT_ROUTE_MAP
   ECOMMUNITY_FORMAT_COMMUNITY_LIST
   ECOMMUNITY_FORMAT_DISPLAY
*/
char *
ecommunity_ecom2str (struct ecommunity *ecom, int format)
{
  int i;
  u_char *pnt;
  int encode = 0;
  int type = 0;
#define ECOMMUNITY_STR_DEFAULT_LEN  26
  int str_size;
  int str_pnt;
  u_char *str_buf;
  char *prefix;
  int len = 0;
  int first = 1;

  /* For parse Extended Community attribute tupple. */
  struct ecommunity_as
  {
    as_t as;
    u_int32_t val;
  } eas;

  struct ecommunity_ip
  {
    struct in_addr ip;
    u_int16_t val;
  } eip;

  if (ecom->size == 0)
    {
      str_buf = XMALLOC (MTYPE_ECOMMUNITY_STR, 1);
      str_buf[0] = '\0';
      return str_buf;
    }

  /* Prepare buffer.  */
  str_buf = XMALLOC (MTYPE_ECOMMUNITY_STR, ECOMMUNITY_STR_DEFAULT_LEN + 1);
  str_size = ECOMMUNITY_STR_DEFAULT_LEN + 1;
  str_pnt = 0;

  for (i = 0; i < ecom->size; i++)
    {
      pnt = ecom->val + (i * 8);

      /* High-order octet of type. */
      encode = *pnt++;
      if (encode != ECOMMUNITY_ENCODE_AS && encode != ECOMMUNITY_ENCODE_IP)
	{
	  if (str_buf)
	    XFREE (MTYPE_ECOMMUNITY_STR, str_buf);
	  return "Unknown";
	}
      
      /* Low-order octet of type. */
      type = *pnt++;
      if (type !=  ECOMMUNITY_ROUTE_TARGET && type != ECOMMUNITY_SITE_ORIGIN)
	{
	  if (str_buf)
	    XFREE (MTYPE_ECOMMUNITY_STR, str_buf);
	  return "Unknown";
	}

      switch (format)
	{
	case ECOMMUNITY_FORMAT_COMMUNITY_LIST:
	  prefix = (type == ECOMMUNITY_ROUTE_TARGET ? "rt " : "soo ");
	  break;
	case ECOMMUNITY_FORMAT_DISPLAY:
	  prefix = (type == ECOMMUNITY_ROUTE_TARGET ? "RT:" : "SoO:");
	  break;
	case ECOMMUNITY_FORMAT_ROUTE_MAP:
	  prefix = "";
	  break;
	default:
	  if (str_buf)
	    XFREE (MTYPE_ECOMMUNITY_STR, str_buf);
	  return "Unknown";
	  break;
	}

      /* Make it sure size is enough.  */
      while (str_pnt + ECOMMUNITY_STR_DEFAULT_LEN >= str_size)
	{
	  str_size *= 2;
	  str_buf = XREALLOC (MTYPE_ECOMMUNITY_STR, str_buf, str_size);
	}

      /* Space between each value.  */
      if (! first)
	str_buf[str_pnt++] = ' ';

      /* Put string into buffer.  */
      if (encode == ECOMMUNITY_ENCODE_AS)
	{
	  eas.as = (*pnt++ << 8);
	  eas.as |= (*pnt++);

	  eas.val = (*pnt++ << 24);
	  eas.val |= (*pnt++ << 16);
	  eas.val |= (*pnt++ << 8);
	  eas.val |= (*pnt++);

	  len = sprintf (str_buf + str_pnt, "%s%d:%d", prefix,
			 eas.as, eas.val);
	  str_pnt += len;
	  first = 0;
	}
      else if (encode == ECOMMUNITY_ENCODE_IP)
	{
	  memcpy (&eip.ip, pnt, 4);
	  pnt += 4;
	  eip.val = (*pnt++ << 8);
	  eip.val |= (*pnt++);

	  len = sprintf (str_buf + str_pnt, "%s%s:%d", prefix,
			 inet_ntoa (eip.ip), eip.val);
	  str_pnt += len;
	  first = 0;
	}
    }
  return str_buf;
}

int
ecommunity_match (struct ecommunity *ecom1, struct ecommunity *ecom2)
{
  int i = 0;
  int j = 0;

  if (ecom1 == NULL && ecom2 == NULL)
    return 1;

  if (ecom1 == NULL || ecom2 == NULL)
    return 0;

  if (ecom1->size < ecom2->size)
    return 0;

  /* Every community on com2 needs to be on com1 for this to match */
  while (i < ecom1->size && j < ecom2->size)
    {
      if (memcmp (ecom1->val + i, ecom2->val + j, ECOMMUNITY_SIZE) == 0)
        j++;
      i++;
    }

  if (j == ecom2->size)
    return 1;
  else
    return 0;
}