On Tue, Sep 15, 2015 at 5:03 PM, Eric Dumazet <eric.duma...@gmail.com> wrote: > On Tue, 2015-09-15 at 16:45 -0700, Tom Herbert wrote: >> > + if (bond->params.xmit_policy == BOND_XMIT_POLICY_ENCAP34 && >> > + skb->l4_hash) >> > + return skb->hash; >> > + >> > if (bond->params.xmit_policy == BOND_XMIT_POLICY_LAYER2 || >> > !bond_flow_dissect(bond, skb, &flow)) >> > return bond_eth_hash(skb); >> > >> > >> Ugh, bond_flow_dissect is yet another instance of customized flow >> dissection! We should really clean this up. I suggest that in cases >> were we want L4 hash a call to skb_get_hash should suffice. We can >> create skb_get_l3hash when caller explicitly wants an L3 hash-- this >> would return skb->hash if it's valid and skb->l4_hash is not set, else >> call flow dissector with FLOW_DISSECTOR_F_STOP_AT_L3 and then do the >> normal hash over flow keys (don't save result in skb->hash in this >> case). > > This code predates all the change you did recently ;) > > BTW, the simple xor weakness is showing up after > our change favoring even ports at connect() time, for a bonding device > with 2 or 4 slaves. > Right, xor as a packet hash should be eliminated. It seems possible that all these modes can be implemented using flow_dissector and the jhash. If I'm reading the meaning of modes correctly:
BOND_XMIT_POLICY_ENCAP34 is equivalent to skb_get_hash BOND_XMIT_POLICY_LAYER23 is flow dissection with FLOW_DISSECTOR_F_STOP_AT_L3 and then normal hash BOND_XMIT_POLICY_LAYER34 is flow dissection with FLOW_DISSECTOR_F_STOP_AT_ENCAP BOND_XMIT_POLICY_LAYER2 would be flow dissection with FLOW_DISSECTOR_F_STOP_AT_L2 (new flag) and then normal hash BOND_XMIT_POLICY_ENCAP23 is a little more interesting. This could be accomplished with custom flow dissector targets that exclude L4 information (ports, flow label, key ID). Also noticed a little bug in flow_dissector, we should get out on FLOW_DISSECTOR_F_STOP_AT_L3 before IPv6 flow label is processed (that's considered L4). I'll fix that. Tom > (commit 07f4c90062f8fc7c8c26f8f95324cbe8fa3145a5 > "tcp/dccp: try to not exhaust ip_local_port_range in connect()") > > > > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
