nuttx/net/utils/net_ipv6_pref2mask.c
Zhe Weng 4c99ad1ba9 net/utils: Switch argument order of net_ipv6_pref2mask
When implementing IPv6-related logic, we found the `net_ipv6_pref2mask`
and `net_ipv6addr_copy` are using different argument order:
```
net_ipv6addr_copy(ifaddr->addr, addr);
net_ipv6_pref2mask(preflen, ifaddr->mask);
```
Change the order to:
```
net_ipv6addr_copy(ifaddr->addr, addr);
net_ipv6_pref2mask(ifaddr->mask, preflen);
```

Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
2023-11-07 19:30:36 +08:00

107 lines
3.3 KiB
C

/****************************************************************************
* net/utils/net_ipv6_pref2mask.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/net/ip.h>
#include "utils/utils.h"
#ifdef CONFIG_NET_IPv6
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: net_ipv6_pref2mask
*
* Description:
* Convert a IPv6 prefix length to a network mask. The prefix length
* specifies the number of MS bits under mask (0-128)
*
* Input Parameters:
* mask - The location to return the netmask.
* preflen - Determines the width of the netmask (in bits). Range 0-128
*
* Returned Value:
* None
*
****************************************************************************/
void net_ipv6_pref2mask(net_ipv6addr_t mask, uint8_t preflen)
{
unsigned int bit;
unsigned int i;
/* Set the network mask. preflen is the number of MS bits under the mask.
*
* Eg. preflen = 38
* NETMASK: ffff ffff fc00 0000 0000 0000 0000 0000
* bit: 1 1..1
* 1 1..3 3..4 4..6 6..7 8..9 9..1 1..2
* 0..5 6..1 2..7 8..3 4..9 0..5 6..1 2..7
* preflen: 1 1..1
* 1 1..3 3..4 4..6 6..8 8..9 9..1 1..2
* 1..6 7..2 3..8 9..4 5..0 1..6 7..2 3..8
*/
for (i = 0; i < 8; i++)
{
/* bit = {0, 16, 32, 48, 64, 80, 96, 112} */
bit = i << 4;
if (preflen > bit)
{
/* Eg. preflen = 38, bit = {0, 16, 32} */
if (preflen >= (bit + 16))
{
/* Eg. preflen = 38, bit = {0, 16} */
mask[i] = 0xffff;
}
else
{
/* Eg. preflen = 38, bit = {32}
* preflen - bit = 6
* mask = 0xffff << (16-6)
* = 0xfc00
*/
mask[i] = HTONS(0xffff << (16 - (preflen - bit)));
}
}
else
{
/* Eg. preflen=38, bit= {48, 64, 80, 96, 112} */
mask[i] = 0x0000;
}
}
}
#endif /* CONFIG_NET_IPv6 */