On Sat, Jun 01, 2019 at 11:04:29AM -0400, Stephen Suryaputra wrote: > On Sat, Jun 01, 2019 at 02:22:30AM +0200, Pablo Neira Ayuso wrote: > > > It is the same as the IPv6 one. The offset returned is the offset to the > > > specific option (target) or the byte beyond the options if the target > > > isn't specified (< 0). > > > > Thanks for explaining. So you are using ipv6_find_hdr() as reference, > > but not sure this offset parameter is useful for this patchset since > > this is always set to zero, do you have plans to use this in a follow > > up patchset? > > I developed this patchset to suit my employer needs and there is no plan > for a follow up patchset, however I think non-zero offset might be useful > in the future for tunneled packets. For tunneled traffic, we can store the network offset in the nft_pktinfo object. Then, add a new extension to update this network offset to point to the network offset inside the tunnel header, and use this pkt->network_offset everywhere. I think this new IPv4 options extension should use priv->offset to match fields inside the IPv4 option specifically, just like in the IPv6 extensions and TCP options do. If you look on how the priv->offset is used in the existing code, this offset points to values that the specific option field conveys. Thanks.
