Re: [libvirt] RFC: Implement virDomainGetIPAddress()

> Wait a minute there please. The MAC address should be unique in the > system so user should be using just one IP address per one MAC address. > Since MAC address should be unique in the system then the IP address > assigned to this MAC address should be just one, shouldn't it ? You can easily add multiple IP address to an interface (and therefore to the same MAC address) ip addr add 192.168.0.17 dev eth0 ip addr add 192.168.0.42 dev eth0

> Nevertheless I think you know more about networking options than I do so Well, I know that there is no strict 1:1 mapping between MAC and IP addresses and I want that this fact is consider in the discussion here and we don't add a new API that turns out to be too simple/restricted in the end. Whether we really want/need to cover this case is a different question.

> when I consider the scenario you wrote me about I don't like the idea of > leaving the parsing to the caller and for the scenario of multiple IP > addresses in the return value I recommend a new prototype: > > char **virDomainGetIPAddress(virDomainPtr domain, char *devmac, unsigned int *count, unsigned int flags); > > > where count will be the output parameter with the number of elements in > the return value. It should be used like: > > virDomainPtr domain = ...; > char *macaddr = "11:22:33:44:55:66"; > char **ips = NULL; > int count = -1; > > ips = virDomainGetIPAddress(domain, macaddr, &count, 0); > > for (i = 0; i < count; i++) { > ... ips[i] ... > ... free(ips[i]) ... > } > > > The return value allocation should be done by the function itself and > the called should free the result (ips in this case). That's a possible way to deal with this, yes. And now lets spin this a bit further and consider IPv6 addresses. ipv4s = virDomainGetIPAddress(domain, macaddr, &count, VIR_DOMAIN_ADDRESS_IPV4); ipv6s = virDomainGetIPAddress(domain, macaddr, &count, VIR_DOMAIN_ADDRESS_IPV6); This are the simple cases where the caller explicitly requests only one version and knows the version of the returned IP addresses. But what about this ips = virDomainGetIPAddress(domain, macaddr, &count, VIR_DOMAIN_ADDRESS_IPV4 | VIR_DOMAIN_ADDRESS_IPV6);