Hi,
On 2016年04月07日 00:06, Rimac, Ivica (Nokia - DE) wrote:
> Hi,
>
> I have implemented and configured a load balancer on an OVS levering the
> nicira multipath extension and using the ovs-ofctl tool. Moving from local
> ovs controls to a RYU app leaves me wondering about some details. Following
> are my ofctl instructions with related questions:
>
> 1. Multipath action
>
> $> ovs-ofctl add-flow ovsbr
> ip,nw_dst=${VIP},actions=multipath(symmetric_l4,1024,hrw,${NUM_LINKS},0,NXM_NX_REG0[0..3]),resubmit(,1)
>
> Q1) The multipath extension is only supported in ofproto_v1_0_parser, correct?
Currently, yes.
the Nicira extensions are not fully ported into ofproto_v1_[2345]_parser...
>
> I am trying to use the classes in my ryu-app to create the corresponding
> actions
>
> -> ofproto_v1_0_parser.NXActionMultipath(…)
>
> -> ofproto_v1_0_parser.NXResubmitTable(…)
>
> I found ofproto.NX_HASH_FIELDS_SYMMETRIC_L4 and ofproto.NX_MP_ALG_HRW for
> the fields and algorithm but wonder
>
> Q2) how to set/address the register NXM_NX_REG0 (and the corresponding bits)
> in NXActionMultipath?
>
> Q3) what is the ofs_nbits param used for in ryu MP Action? (There is no such
> argument in the ofctl multipath action.)
>
> 2. Register match
>
> $> ovs-ofctl add-flow ovsbr
> table=1,reg0=0/15,actions=mod_dl_dst=${MAC},output:${OFPORT}
>
> Q4) How do I read the value (hash) previously written into reg0 by the
> multipath action? (related to Q1)
For Q2,3,4, please refer to the following snippet.
$ git diff
diff --git a/ryu/app/simple_switch.py b/ryu/app/simple_switch.py
index 862b830..0666deb 100644
--- a/ryu/app/simple_switch.py
+++ b/ryu/app/simple_switch.py
@@ -20,7 +20,7 @@ An OpenFlow 1.0 L2 learning switch implementation.
from ryu.base import app_manager
from ryu.controller import ofp_event
-from ryu.controller.handler import MAIN_DISPATCHER
+from ryu.controller.handler import MAIN_DISPATCHER, CONFIG_DISPATCHER
from ryu.controller.handler import set_ev_cls
from ryu.ofproto import ofproto_v1_0
from ryu.lib.mac import haddr_to_bin
@@ -28,6 +28,9 @@ from ryu.lib.packet import packet
from ryu.lib.packet import ethernet
from ryu.lib.packet import ether_types
+from ryu.ofproto import nx_match
+from ryu.ofproto import nicira_ext
+
class SimpleSwitch(app_manager.RyuApp):
OFP_VERSIONS = [ofproto_v1_0.OFP_VERSION]
@@ -36,6 +39,44 @@ class SimpleSwitch(app_manager.RyuApp):
super(SimpleSwitch, self).__init__(*args, **kwargs)
self.mac_to_port = {}
+ @set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
+ def switch_features_handler(self, ev):
+ datapath = ev.msg.datapath
+ ofproto = datapath.ofproto
+ parser = datapath.ofproto_parser
+
+ # Register match in ovs-ofctl command is corresponding as follows:
+ # format)
+ # reg<reg_index>=value/mask
+ # nx_match.ClsRule.set_reg_masked(self, reg_idx, value, mask)
+ # e.g.)
+ # reg0=0/15
+ rule = nx_match.ClsRule()
+ rule.set_reg_masked(0, 0x0, 0x15)
+
+ # Multipath action in ovs-ofctl command is corresponding as follows:
+ # format)
+ # multipath(fields, basis, algorithm, n_links, arg, dst[start..end])
+ # NXActionMultipath.__init__(
+ # self,fields, basis, algorithm, max_link, arg, ofs_nbits, dst)
+ # * Note: max_link = n_links - 1.
+ # ofs_nbits = ((start << 6) | end)
+ # e.g.)
+ # multipath(symmetric_l4,1024,hrw,6,0,NXM_NX_REG0[0..3])
+ actions = [parser.NXActionMultipath(
+ fields=nicira_ext.NX_HASH_FIELDS_SYMMETRIC_L4,
+ basis=1024,
+ algorithm=nicira_ext.NX_MP_ALG_HRW,
+ max_link=5,
+ arg=0,
+ ofs_nbits=((0 << 6) | 3),
+ dst=ofproto.nxm_nx_reg(0))]
+
+ # Send nxt_flow_mod by using the utility method of Datapath class
+ datapath.send_flow_mod(
+ rule=rule, cookie=0, command=ofproto.OFPFC_ADD,
+ idle_timeout=0, hard_timeout=0, actions=actions)
+
def add_flow(self, datapath, in_port, dst, actions):
ofproto = datapath.ofproto
$ sudo ovs-ofctl dump-flows s1
NXST_FLOW reply (xid=0x4):
cookie=0x0, duration=3.228s, table=0, n_packets=2, n_bytes=140, idle_age=2,
reg0=0/0x15 actions=multipath(symmetric_l4,1024,hrw,6,0,NXM_NX_REG0[0..3])
Thanks,
Iwase
>
> I appreciate any help since I am new to RYU and don’t seem to find answers
> myself by going through the ryu code base.
>
> Ivica
>
>
>
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