[pim] Initial pim 0.155
diff --git a/pimd/pim_util.c b/pimd/pim_util.c
new file mode 100644
index 0000000..5bc8d07
--- /dev/null
+++ b/pimd/pim_util.c
@@ -0,0 +1,132 @@
+/*
+ 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 "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 */