Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx> writes: >> Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx> writes: >> >> >> Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx> writes: >> >> >> >> >> On Wed, 28 Nov 2018 13:36:26 +0100 >> >> >> Toke Høiland-Jørgensen <toke@xxxxxxx> wrote: >> >> >> > > [...] > >> >> > >> >> > I guess it will be enough to avoid loading a 'non-WiFi' bpf program on >> >> > a 802.11 netdevice (and vice versa). We could add a flag (or something >> >> > similar) in XDP_SETUP_PROG section of netdev_bpf data structure and >> >> > use ieee80211_ptr netdevice pointer in order to guarantee that the bpf >> >> > program will work on the expected 'frame-type' >> >> >> >> Yeah, a flag would be good; we've been discussing that for other XDP use >> >> cases; it's not a done deal yet, but I think it would be useful. >> > >> > Do you think something wifi specific is ok (e.g bool wifi) or do you prefer >> > something more general (e.g u32 frame_type)? >> >> My thought was a feature flag where the program can set a flag which >> means "I expect 802.11 frames", and the driver can set a flag saying "I >> emit 802.11 frames", and if those two flags don't match, the verifier >> can refuse to load the program. This would not be fool-proof (an XDP >> program can still corrupt things if written incorrectly), but it would >> at least protect against the most obvious mistakes. > > I guess we can use iee80211_ptr in dev_xdp_install to double check if it is > allowed to upload a 802.11 (or 802.3) bpf program Yeah, I think it's more an issue of convincing the wider XDP community that support for feature flags is in fact needed ;) -Toke
