"Zhang, Chen" <chen.zh...@intel.com> writes: >> -----Original Message----- >> From: Markus Armbruster <arm...@redhat.com> >> Sent: Wednesday, June 16, 2021 2:04 PM >> To: Zhang, Chen <chen.zh...@intel.com> >> Cc: Lukas Straub <lukasstra...@web.de>; Daniel P.Berrangé >> <berra...@redhat.com>; Li Zhijian <lizhij...@cn.fujitsu.com>; Jason Wang >> <jasow...@redhat.com>; qemu-dev <qemu-devel@nongnu.org>; Dr. David >> Alan Gilbert <dgilb...@redhat.com>; Gerd Hoffmann <kra...@redhat.com>; >> Zhang Chen <zhangc...@gmail.com>; Eric Blake <ebl...@redhat.com> >> Subject: Re: [PATCH V8 1/6] qapi/net: Add IPFlowSpec and QMP command >> for COLO passthrough >> >> "Zhang, Chen" <chen.zh...@intel.com> writes: >> >> >> -----Original Message----- >> >> From: Markus Armbruster <arm...@redhat.com> >> >> Sent: Tuesday, June 15, 2021 10:43 PM >> >> To: Zhang, Chen <chen.zh...@intel.com> >> >> Cc: Jason Wang <jasow...@redhat.com>; qemu-dev <qemu- >> >> de...@nongnu.org>; Eric Blake <ebl...@redhat.com>; Dr. David Alan >> >> Gilbert <dgilb...@redhat.com>; Daniel P.Berrangé >> >> <berra...@redhat.com>; Gerd Hoffmann <kra...@redhat.com>; Li >> Zhijian >> >> <lizhij...@cn.fujitsu.com>; Lukas Straub <lukasstra...@web.de>; Zhang >> >> Chen <zhangc...@gmail.com> >> >> Subject: Re: [PATCH V8 1/6] qapi/net: Add IPFlowSpec and QMP >> command >> >> for COLO passthrough >> >> >> >> Zhang Chen <chen.zh...@intel.com> writes: >> >> >> >> > Since the real user scenario does not need COLO to monitor all traffic. >> >> > Add colo-passthrough-add and colo-passthrough-del to maintain a >> >> > COLO network passthrough list. Add IPFlowSpec struct for all QMP >> >> > commands. >> >> > All the fields of IPFlowSpec are optional. >> >> > >> >> > Signed-off-by: Zhang Chen <chen.zh...@intel.com> >> >> > --- >> >> >> >> The QAPI schema looks good to me, but the interface documentation is >> >> still not quite clear enough. To make progress, I'm going to make >> >> concrete suggestions wherever I can despite being quite clueless >> >> about the subject matter. Risks me writing something that's clearer, >> >> but wrong. Keep that in mind, please. >> >> >> >> > net/net.c | 10 +++++++ >> >> > qapi/net.json | 74 >> >> > +++++++++++++++++++++++++++++++++++++++++++++++++++ >> >> > 2 files changed, 84 insertions(+) >> >> > >> >> > diff --git a/net/net.c b/net/net.c >> >> > index 76bbb7c31b..f913e97983 100644 >> >> > --- a/net/net.c >> >> > +++ b/net/net.c >> >> > @@ -1195,6 +1195,16 @@ void qmp_netdev_del(const char *id, Error **errp) >> >> > } >> >> > } >> >> > >> >> > +void qmp_colo_passthrough_add(IPFlowSpec *spec, Error **errp) { >> >> > + /* TODO implement setup passthrough rule */ } >> >> > + >> >> > +void qmp_colo_passthrough_del(IPFlowSpec *spec, Error **errp) { >> >> > + /* TODO implement delete passthrough rule */ } >> >> > + >> >> > static void netfilter_print_info(Monitor *mon, NetFilterState *nf) { >> >> > char *str; >> >> > diff --git a/qapi/net.json b/qapi/net.json index >> >> > 7fab2e7cd8..91f2e1495a 100644 >> >> > --- a/qapi/net.json >> >> > +++ b/qapi/net.json >> >> > @@ -7,6 +7,7 @@ >> >> > ## >> >> > >> >> > { 'include': 'common.json' } >> >> > +{ 'include': 'sockets.json' } >> >> > >> >> > ## >> >> > # @set_link: >> >> > @@ -696,3 +697,76 @@ >> >> > ## >> >> > { 'event': 'FAILOVER_NEGOTIATED', >> >> > 'data': {'device-id': 'str'} } >> >> > + >> >> > +## >> >> > +# @IPFlowSpec: >> >> > +# >> >> > +# IP flow specification. >> >> > +# >> >> > +# @protocol: Transport layer protocol like TCP/UDP, etc. The protocol >> >> > is the >> >> > +# string instead of enum, because it can be passed to >> >> > getprotobyname(3) >> >> > +# and avoid duplication with /etc/protocols. >> >> >> >> The rationale is good, but it doesn't really belong into the >> >> interface documentation. Suggest: >> >> >> >> # @protocol: Transport layer protocol like TCP/UDP, etc. This will be >> >> # passed to getprotobyname(3). >> >> >> > >> > OK. >> > >> >> >> >> > +# >> >> > +# @object-name: The @object-name means packet handler in Qemu. Because >> >> > not >> >> > +# all the network packet must pass the colo-compare >> >> > module, >> >> > +# the net-filters are same situation. There modules >> >> > attach to >> >> > +# netdev or chardev to work, VM can run multiple modules >> >> > +# at the same time. So it needs the object-name to set >> >> > +# the effective module. >> >> >> >> I still don't understand this, and I'm too ignorant of COLO and >> >> networking to suggest improvements. >> > >> > Let me use qemu boot parameter to clear it. >> > For colo-compare, it needs chardev as the source to handle network packet. >> > -object >> > colo-compare,id=comp0,primary_in=chardev-input0,secondary_in=chardev-input1,outdev=chardev-output0,iothread=iothread0. >> > >> > For net filters, it needs attached on netdev. >> > -object >> > filter-redirector,id=red0,netdev=hn0,queue=rx,outdev=chardev-output1 >> > -object filter-mirror,id=mirror0,netdev=hn0,queue=rx,outdev=chardev-output2 >> > >> > And we can use -chardev socket combine the filter and the colo-compare. >> > >> > Back to the @object-name, One guest maybe have multi colo-compare as the >> > same time, with different object name from different source. >> > So we need assign the IPFlowSpec to one object as the handler. Same as the >> > net-filters. >> > Each object instance has its own passthrough list. >> >> So the @object-name here references one of the "packet handler objects" >> (colo-compare, filter-redirector, filter-mirror) by @id. Correct? > > Yes. > >> >> In other words, @object-name is the ID of a QOM object, and the QOM >> object must be of a certain kind (i.e. provide certain functionality). >> Correct? > > Yes.
Got it. >> What exactly makes a QOM object a "packet handler object?" >> > > Firstly, the original object need have basic network packet input/output > capability. > It's a good question, maybe we need add a flag in general object structure to > show the capability. A QOM interface might fit the bill: a QOM type is a packet handler if and only if it implements the packet handler interface. >> Right now, the packet handler object types are colo-compare, filter- >> redirector, filter-mirror, and that's all. Correct? > > No, this series just make colo-compare become a packet handler, This is a > beginning, I plan to make other filters support it. Okay. Are these other filters similarly related to COLO? I'm asking because the commands are called colo-passthrough-FOO. If this goes beyond COLO, we may want to name them differently. >> Another question the doc comment needs to answer: what happens when >> @object-name is absent? > > Please see the explanation below. You seem to consider making it mandatory there. My question would be moot then. >> >> Jason or David, perhaps? >> >> >> >> > +# >> >> > +# @source: Source address and port. >> >> > +# >> >> > +# @destination: Destination address and port. >> >> > +# >> >> > +# Since: 6.1 >> >> > +## >> >> > +{ 'struct': 'IPFlowSpec', >> >> > + 'data': { '*protocol': 'str', '*object-name': 'str', >> >> > + '*source': 'InetSocketAddressBase', >> >> > + '*destination': 'InetSocketAddressBase' } } >> >> > + >> >> > +## >> >> > +# @colo-passthrough-add: >> >> > +# >> >> > +# Add passthrough entry IPFlowSpec to the COLO-compare instance. >> >> > +# The protocol and source/destination IP/ports are optional. if >> >> > +the user # only inputs part of the information, this will match all >> >> > traffic. >> >> >> >> Actually, all arguments are optional. >> >> >> >> Suggest: >> >> >> >> # Add an entry to the COLO network passthrough list. >> >> # Absent protocol, host addresses and ports match anything. >> >> >> >> If there is more than one such list, then "to a COLO network passthrough >> >> list" >> >> instead. >> > >> > Yes, more than one list. >> > >> >> >> >> Still missing then: meaning of absent @object-name. Does it select >> >> the COLO network passthrough list, perhaps? >> > >> > Yes, Please see the explanation above. Each object instance has its own >> > passthrough list. >> >> Got it now. >> >> >> > +# >> >> > +# Returns: Nothing on success >> >> > +# >> >> > +# Since: 6.1 >> >> > +# >> >> > +# Example: >> >> > +# >> >> > +# -> { "execute": "colo-passthrough-add", >> >> > +# "arguments": { "protocol": "tcp", "object-name": "object0", >> >> > +# "source": {"host": "192.168.1.1", "port": "1234"}, >> >> > +# "destination": {"host": "192.168.1.2", "port": "4321"} } } >> >> > +# <- { "return": {} } >> >> > +# >> >> > +## >> >> > +{ 'command': 'colo-passthrough-add', 'boxed': true, >> >> > + 'data': 'IPFlowSpec' } >> >> > + >> >> > +## >> >> > +# @colo-passthrough-del: >> >> > +# >> >> > +# Delete passthrough entry IPFlowSpec to the COLO-compare instance. >> >> > +# The protocol and source/destination IP/ports are optional. if >> >> > +the user # only inputs part of the information, this will match all >> >> > traffic. >> >> >> >> I suspect this command doesn't actually match traffic, it matches >> >> entries added with colo-passthrough-add. >> > >> > Yes. >> > >> >> >> >> Can it delete more than one such entry? >> >> >> > >> > Currently no, but it easy to match one more entry to delete. >> >> If the passthrough list entries had some unique ID, we could refer to one >> entry by its ID. It's how things commonly work. >> >> Without an ID, we need to match by value, like you do. I can see three >> possible behaviors: >> >> 1. Select first entry that matches. >> >> 2. Select all entries that match. >> >> 3. If exactly one entry matches, select it. >> >> The second design choice is behavior when nothing gets selected: >> >> a. Silently do nothing >> >> b. Error >> >> Which one did you implement? My guess based on your answers is 1a. > > Re-think about it, If we want to match by value, we need know which object > have the capability and search in each object passthrough list. > Obviously, we haven't such flag in object structure. So It more reasonable to > make @object-name as a must at the beginning. > Because the passthrough list always in the network handler object. Maybe we > need a global passthrough list for each guest to handle it in the future. > It will have two-level passthrough list to control network. I'm not sure I understand. If you make @object-name mandatory both for colo-passthrough-add and colo-passthrough-del, then we can simply use @object-name to find the object, check it implements the packet handler interface, use the packet handler interface to get its passthrough list, then add to / delete from that list. If we find a use for making @object-name optional later, we can do so without breaking compatibility.