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/*
PIM for Quagga
Copyright (C) 2008 Everton da Silva Marques
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; see the file COPYING; if not, write to the
Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
MA 02110-1301 USA
$QuaggaId: $Format:%an, %ai, %h$ $
*/
#include <zebra.h>
#include "log.h"
#include "pim_util.h"
/*
RFC 3376: 4.1.7. QQIC (Querier's Query Interval Code)
If QQIC < 128, QQI = QQIC
If QQIC >= 128, QQI = (mant | 0x10) << (exp + 3)
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|1| exp | mant |
+-+-+-+-+-+-+-+-+
Since exp=0..7 then (exp+3)=3..10, then QQI has
one of the following bit patterns:
exp=0: QQI = 0000.0000.1MMM.M000
exp=1: QQI = 0000.0001.MMMM.0000
...
exp=6: QQI = 001M.MMM0.0000.0000
exp=7: QQI = 01MM.MM00.0000.0000
--------- ---------
0x4 0x0 0x0 0x0
*/
uint8_t igmp_msg_encode16to8(uint16_t value)
{
uint8_t code;
if (value < 128) {
code = value;
}
else {
uint16_t mask = 0x4000;
uint8_t exp;
uint16_t mant;
for (exp = 7; exp > 0; --exp) {
if (mask & value)
break;
mask >>= 1;
}
mant = 0x000F & (value >> (exp + 3));
code = ((uint8_t) 1 << 7) | ((uint8_t) exp << 4) | (uint8_t) mant;
}
return code;
}
/*
RFC 3376: 4.1.7. QQIC (Querier's Query Interval Code)
If QQIC < 128, QQI = QQIC
If QQIC >= 128, QQI = (mant | 0x10) << (exp + 3)
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|1| exp | mant |
+-+-+-+-+-+-+-+-+
*/
uint16_t igmp_msg_decode8to16(uint8_t code)
{
uint16_t value;
if (code < 128) {
value = code;
}
else {
uint16_t mant = (code & 0x0F);
uint8_t exp = (code & 0x70) >> 4;
value = (mant | 0x10) << (exp + 3);
}
return value;
}
#ifndef PIM_USE_QUAGGA_INET_CHECKSUM
/*
RFC 3376: 4.1.2. Checksum
The Checksum is the 16-bit one's complement of the one's complement
sum of the whole IGMP message (the entire IP payload). For
computing the checksum, the Checksum field is set to zero. When
receiving packets, the checksum MUST be verified before processing a
packet. [RFC-1071]
*/
uint16_t pim_inet_checksum(const char *buf, int size)
{
const uint16_t *ptr;
uint32_t sum;
uint16_t checksum;
ptr = (const uint16_t *) buf;
sum = 0;
while (size > 1) {
sum += *ptr;
++ptr;
size -= 2;
}
/* Add left-over byte, if any */
if (size > 0)
sum += (uint16_t) *(const uint8_t *) ptr;
/* Fold 32-bit sum to 16 bits */
sum = (sum & 0xffff) + (sum >> 16);
checksum = ~sum;
return checksum;
}
#endif /* PIM_USE_QUAGGA_INET_CHECKSUM */
void pim_pkt_dump(const char *label, const uint8_t *buf, int size)
{
char dump_buf[1000];
int i = 0;
int j = 0;
for (; i < size; ++i, j += 2) {
int left = sizeof(dump_buf) - j;
if (left < 4) {
if (left > 1) {
strcat(dump_buf + j, "!"); /* mark as truncated */
}
break;
}
snprintf(dump_buf + j, left, "%02x", buf[i]);
}
zlog_debug("%s: pkt dump size=%d: %s",
label,
size,
dump_buf);
}
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