On 03.11.2016 08:42, Shmulik Ladkani wrote: > On Wed, 2 Nov 2016 16:36:17 -0400 > Lance Richardson <lrich...@redhat.com> wrote: > >> - /* common case: fragmentation of segments is not allowed, >> - * or seglen is <= mtu >> + /* common case: seglen is <= mtu >> */ >> - if (((IPCB(skb)->flags & IPSKB_FRAG_SEGS) == 0) || >> - skb_gso_validate_mtu(skb, mtu)) >> + if (skb_gso_validate_mtu(skb, mtu)) >> return ip_finish_output2(net, sk, skb); > > OK. > Resembles https://patchwork.ozlabs.org/patch/644724/ ;) > >> - if (skb_iif && !(df & htons(IP_DF))) { >> - /* Arrived from an ingress interface, got encapsulated, with >> - * fragmentation of encapulating frames allowed. >> - * If skb is gso, the resulting encapsulated network segments >> - * may exceed dst mtu. >> - * Allow IP Fragmentation of segments. >> - */ >> - IPCB(skb)->flags |= IPSKB_FRAG_SEGS; >> - } > > The only potential issue I see removing this, is that the KNOWLEDGE of > the forwarding/tunnel-bridging usecases (that require a > skb_gso_validate_mtu check) is lost. > > Meaning, if one decides (as claimed in the past) that locally generated > traffic must NOT go through fragmentation validation, then no one > remembers those other valid usecases (which are very specific and not > trivial to imagine) that MUST go through it; Therefore it can easily get > broken.
I agree but I think the git changelog reassembles the changes in this area in good enough detail and it can be added if there is need for that currently I don't see a reason why to leave this code there. I am a bit sad to remove this condition, but the alternative, to generate oversized frames, is absolutely not acceptable. :/ Thanks, Hannes
