[libvirt] [PATCH 1/3] Utility functions to produce an IPv4 broadcast address

[Laine Stump]

On 12/31/2010 08:08 AM, Stefan Berger wrote:
> On 12/31/2010 06:33 AM, Laine Stump wrote:
>> These functions work only for IPv4, becasue IPv6 doesn't have the same
>> concept of "broadcast address" as IPv4. They merely OR the inverse of
>> the netmask with the given host address, thus turning on all the host
>> bits.
>> ---
>>   src/libvirt_private.syms |    2 +
>>   src/util/network.c       |   55 
>> ++++++++++++++++++++++++++++++++++++++++++++++
>>   src/util/network.h       |    6 +++++
>>   3 files changed, 63 insertions(+), 0 deletions(-)
>>
>> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
>> index a959ad9..19e581c 100644
>> --- a/src/libvirt_private.syms
>> +++ b/src/libvirt_private.syms
>> @@ -558,6 +558,8 @@ virShrinkN;
>>
>>
>>   # network.h
>> +virSocketAddrBroadcast;
>> +virSocketAddrBroadcastByPrefix;
>>   virSocketAddrIsNetmask;
>>   virSocketAddrMask;
>>   virSocketAddrMaskByPrefix;
>> diff --git a/src/util/network.c b/src/util/network.c
>> index 61044fc..f58986e 100644
>> --- a/src/util/network.c
>> +++ b/src/util/network.c
>> @@ -341,6 +341,61 @@ virSocketAddrMaskByPrefix(virSocketAddrPtr addr, 
>> unsigned int prefix)
>>   }
>>
>>   /**
>> + * virSocketAddrBroadcast:
>> + * @addr: address that needs to be turned into broadcast address 
>> (IPv4 only)
>> + * @netmask: the netmask address
>> + * @broadcast: virSocketAddr to recieve the broadcast address
>> + *
>> + * Mask ON the host bits of @addr according to @netmask, turning it
>> + * into a broadcast address.
>> + *
>> + * Returns 0 in case of success, or -1 on error.
>> + */
>> +int
>> +virSocketAddrBroadcast(const virSocketAddrPtr addr,
>> +                       const virSocketAddrPtr netmask,
>> +                       virSocketAddrPtr       broadcast)
>> +{
>> +    if ((addr->data.stor.ss_family != AF_INET) ||
>> +        (netmask->data.stor.ss_family != AF_INET)) {
>> +        broadcast->data.stor.ss_family = AF_UNSPEC;
>> +        return -1;
>> +    }
>> +
>> +    broadcast->data.stor.ss_family = AF_INET;
>> +    broadcast->len = addr->len;
>> +    broadcast->data.inet4.sin_addr.s_addr
>> +        = (addr->data.inet4.sin_addr.s_addr
>> +           | ~netmask->data.inet4.sin_addr.s_addr);
>> +    return 0;
>> +}
>> +
>> +/**
>> + * virSocketAddrBroadcastByPrefix:
>> + * @addr: address that needs to be turned into broadcast address 
>> (IPv4 only)
>> + * @prefix: prefix (# of 1 bits) of netmask to apply
>> + * @broadcast: virSocketAddr to recieve the broadcast address
>> + *
>> + * Mask off the host bits of @addr according to @prefix, turning it
>> + * into a network address.
>> + *
>> + * Returns 0 in case of success, or -1 on error.
>> + */
>> +int
>> +virSocketAddrBroadcastByPrefix(const virSocketAddrPtr addr,
>> +                               unsigned int           prefix,
>> +                               virSocketAddrPtr       broadcast)
>> +{
>> +    virSocketAddr netmask;
>> +
>> +    if (virSocketAddrPrefixToNetmask(prefix,&netmask,
>> +                                     addr->data.stor.ss_family)<  0)
>> +        return -1;
>> +
>> +    return virSocketAddrBroadcast(addr,&netmask, broadcast);
>> +}
>> +
>> +/**
>>    * virSocketCheckNetmask:
>>    * @addr1: a first network address
>>    * @addr2: a second network address
>> diff --git a/src/util/network.h b/src/util/network.h
>> index 2fcee43..bcbc607 100644
>> --- a/src/util/network.h
>> +++ b/src/util/network.h
>> @@ -77,6 +77,12 @@ int virSocketAddrMask     (virSocketAddrPtr addr,
>>                              const virSocketAddrPtr netmask);
>>   int virSocketAddrMaskByPrefix(virSocketAddrPtr addr,
>>                                 unsigned int prefix);
>> +int virSocketAddrBroadcast(const virSocketAddrPtr addr,
>> +                           const virSocketAddrPtr netmask,
>> +                           virSocketAddrPtr       broadcast);
>> +int virSocketAddrBroadcastByPrefix(const virSocketAddrPtr addr,
>> +                                   unsigned int           prefix,
>> +                                   virSocketAddrPtr       broadcast);
>>
>>   int virSocketGetNumNetmaskBits(const virSocketAddrPtr netmask);
>>   int virSocketAddrPrefixToNetmask(unsigned int prefix,
> ACK.

Thanks, Stefan. Pushed.