On Mon, Jun 4, 2018 at 8:51 AM 吉藤英明 <hideaki.yoshif...@miraclelinux.com> wrote: > > > + if (ipv6_get_lladdr(dev, &lladdr, IFA_F_TENTATIVE)) > > + get_random_bytes(eui, 8); > > Please be aware of I/G bit and G/L bit.
Actually, I think this is fine. RFC 7136 clarified this, and says: ====== Thus, we can conclude that the value of the "u" bit in IIDs has no particular meaning. In the case of an IID created from a MAC address according to RFC 4291, its value is determined by the MAC address, but that is all. [...] Specifications of other forms of 64-bit IIDs MUST specify how all 64 bits are set, but a generic semantic meaning for the "u" and "g" bits MUST NOT be defined. However, the method of generating IIDs for specific link types MAY define some local significance for certain bits. In all cases, the bits in an IID have no generic semantics; in other words, they have opaque values. In fact, the whole IID value MUST be viewed as an opaque bit string by third parties, except possibly in the local context. ====== That said - we already have a way to form all-random IIDs: IN6_ADDR_GEN_MODE_RANDOM. Can't you just ensure that links of type ARPHRD_RAWIP always use IN6_ADDR_GEN_MODE_RANDOM? That might lead to less special-casing.
