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For wifi clients the nl80211 can inform us about new clients. This may also be possible for bridges.

Relevant kernel code:

• RTM_NEWNEIGH
• http://lxr.free-electrons.com/source/net/bridge/br_fdb.c#L547
• http://lxr.free-electrons.com/source/net/bridge/br_fdb.c#L682

when running l3roamd the kernel module cfg80211 must be loaded otherwise l3roamd exits with the message:
"nl80211 not found"

the error message seems to be originating from wifistations.c

106 int nl80211_id = genl_ctrl_resolve(ctx->nl_sock, "nl80211");
107 if (nl80211_id < 0) {
108 fprintf(stderr, "nl80211 not found.\n");
109 goto fail;
110 }

should l3roamd really depend on cfg80211 even if the system that it runs on does not contain wifi hardware?

Gibt es irgendwo schon eine Anleitung wie man l3 baut und fürs debuggen auf einem Router laufen lässt?

Nodes could generate a special IP address generated using a clients MAC address (like: PREFIX::MAC), announce a local route and assign this address to lo. A node claiming a client would first look for a route to this special IP address and if it is present contact the node previously serving the client using this address to initiate a smooth handover.

Maybe use fec0::/10?

It may suffice to only store client information on a single node. In case this node disappears, routes to clients can be rediscovered when needed. This may cause slight hiccups.

If we do this, we'd need the ability to query the network for a specific client given its MAC address.

Basically we need two new packet types:

• request information about a MAC (should be flooded for now)
• response containing list of IPs for that MAC

Information about a MAC should be requested whenever a new client appears, even if local information is available

The request actually claims the client. If another node thinks it owns the client, it'll compare the timestamp. If the other node has a younger timestamp, it won't respond but instead claim the client itself (by sending a request).Otherwise, it'll respond and let got of the client.

• clientmgr_handle_claim dazu umbauen

maybe a rw-socket is a solution like babeld already implements it?

having tested l3roamd in versions 14e87ca (april 14th) and beed337 (may 10th) in the same environment the l3roamd built from master does not create host-routes for connected clients rendering the network unusable. So it seems that something in l3roamd broke between those two commits.

Check interval should be something like 5 minutes (configurable).

If an IP does not respond for twice the interval the IP and the route is removed.

• A client with IP should be forgotten altogether.

• are all allocs (malloc/calloc) freed?

• periodically contact client (neighbor solicitation)
• update timestamp on reply
• purge clients that haven't responded for a while (also purge routes!)

I was able to capture this log. A new client (00:18:de:24:c6:7c) appears but it does not receive an IP address. In the same configuration in another connection attempt everything works.

What needs fixing?

Sun Nov 27 18:54:38 2016 daemon.info l3roamd[871]: client0: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)
Sun Nov 27 18:54:38 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 (865.217705780)
Sun Nov 27 18:54:38 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff20:92a2
Sun Nov 27 18:54:38 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:54:38 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE
Sun Nov 27 18:54:39 2016 daemon.info l3roamd[871]: event 19
Sun Nov 27 18:54:39 2016 daemon.info l3roamd[871]: client0: new station 00:18:de:24:c6:7c
Sun Nov 27 18:54:39 2016 daemon.info l3roamd[871]: new client 00:18:de:24:c6:7c on br-client
Sun Nov 27 18:54:39 2016 daemon.info l3roamd[871]: event 60
Sun Nov 27 18:54:39 2016 daemon.info l3roamd[871]: client0: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:54:39 2016 daemon.info hostapd: client0: STA 00:18:de:24:c6:7c IEEE 802.11: authenticated
Sun Nov 27 18:54:39 2016 daemon.info hostapd: client0: STA 00:18:de:24:c6:7c IEEE 802.11: associated (aid 1)
Sun Nov 27 18:54:39 2016 daemon.info l3roamd[871]: event 60
Sun Nov 27 18:54:39 2016 kern.warn kernel: [ 871.040000] REJECT(src client)IN=br-client OUT= MAC=ff:ff:ff:ff:ff:ff:00:18:de:24:c6:7c:08:00 SRC=0.0.0.0 DST=255.255.255.255 LEN=328 TOS=0x10 PREC=0x00 TTL=128 ID=0 PROTO=UDP SPT=68 DPT=67 LEN=308
Sun Nov 27 18:54:41 2016 daemon.info fastd[1597]: resolving host gw02.babel.ffm.freifunk.net' for peer <mesh_vpn_backbone_peer_fastd2>... Sun Nov 27 18:54:41 2016 daemon.info fastd[1597]: resolving host gw02.babel.ffm.freifunk.net' failed: Name or service not known
Sun Nov 27 18:54:42 2016 kern.warn kernel: [ 873.550000] REJECT(src client)IN=br-client OUT= MAC=ff:ff:ff:ff:ff:ff:00:18:de:24:c6:7c:08:00 SRC=0.0.0.0 DST=255.255.255.255 LEN=328 TOS=0x10 PREC=0x00 TTL=128 ID=0 PROTO=UDP SPT=68 DPT=67 LEN=308
Sun Nov 27 18:54:43 2016 daemon.info l3roamd[871]: client0: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)
Sun Nov 27 18:54:43 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 (870.218194250)
Sun Nov 27 18:54:43 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff20:92a2
Sun Nov 27 18:54:43 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:54:43 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE
Sun Nov 27 18:54:44 2016 daemon.info l3roamd[871]: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:54:48 2016 daemon.info l3roamd[871]: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)
Sun Nov 27 18:54:48 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 (875.218978220)
Sun Nov 27 18:54:48 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff20:92a2
Sun Nov 27 18:54:48 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:54:48 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE
Sun Nov 27 18:54:48 2016 kern.warn kernel: [ 880.240000] REJECT(src client)IN=br-client OUT= MAC=ff:ff:ff:ff:ff:ff:00:18:de:24:c6:7c:08:00 SRC=0.0.0.0 DST=255.255.255.255 LEN=328 TOS=0x10 PREC=0x00 TTL=128 ID=0 PROTO=UDP SPT=68 DPT=67 LEN=308
Sun Nov 27 18:54:49 2016 daemon.info l3roamd[871]: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:54:53 2016 daemon.info l3roamd[871]: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)
Sun Nov 27 18:54:53 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 (880.219782270)
Sun Nov 27 18:54:53 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff20:92a2
Sun Nov 27 18:54:53 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:54:53 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE
Sun Nov 27 18:54:54 2016 daemon.info l3roamd[871]: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:54:58 2016 daemon.info l3roamd[871]: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)
Sun Nov 27 18:54:58 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 (885.220328500)
Sun Nov 27 18:54:58 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff20:92a2
Sun Nov 27 18:54:58 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:54:58 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE
Sun Nov 27 18:54:59 2016 daemon.info l3roamd[871]: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:55:00 2016 kern.warn kernel: [ 891.740000] REJECT(src client)IN=br-client OUT= MAC=ff:ff:ff:ff:ff:ff:00:18:de:24:c6:7c:08:00 SRC=0.0.0.0 DST=255.255.255.255 LEN=328 TOS=0x10 PREC=0x00 TTL=128 ID=0 PROTO=UDP SPT=68 DPT=67 LEN=308
Sun Nov 27 18:55:02 2016 daemon.info fastd[1597]: resolving host gw02.babel.ffm.freifunk.net' for peer <mesh_vpn_backbone_peer_fastd2>... Sun Nov 27 18:55:02 2016 daemon.info fastd[1597]: resolving host gw02.babel.ffm.freifunk.net' failed: Name or service not known
Sun Nov 27 18:55:03 2016 daemon.info l3roamd[871]: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)

as opposed to a different connection try, when everything seems to work in the same configuration, just a while later.
Nov 27 18:56:33 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:56:33 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE
Sun Nov 27 18:56:34 2016 daemon.info l3roamd[871]: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:56:38 2016 daemon.info l3roamd[871]: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)
Sun Nov 27 18:56:38 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 (985.257362680)
Sun Nov 27 18:56:38 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff20:92a2
Sun Nov 27 18:56:38 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:56:38 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE
Sun Nov 27 18:56:39 2016 daemon.info l3roamd[871]: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:56:42 2016 daemon.info fastd[1597]: resolving host gw02.babel.ffm.freifunk.net' for peer <mesh_vpn_backbone_peer_fastd2>... Sun Nov 27 18:56:42 2016 daemon.info fastd[1597]: resolving host gw02.babel.ffm.freifunk.net' failed: Name or service not known
Sun Nov 27 18:56:43 2016 daemon.info l3roamd[871]: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)
Sun Nov 27 18:56:43 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 (990.256023740)
Sun Nov 27 18:56:43 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff20:92a2
Sun Nov 27 18:56:43 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:56:43 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE
Sun Nov 27 18:56:44 2016 daemon.info l3roamd[871]: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:56:44 2016 daemon.info l3roamd[871]: event 60
Sun Nov 27 18:56:47 2016 daemon.info l3roamd[871]: client0: event 19
Sun Nov 27 18:56:47 2016 daemon.info l3roamd[871]: client0: new station 00:18:de:24:c6:7c
Sun Nov 27 18:56:47 2016 daemon.info l3roamd[871]: new client 00:18:de:24:c6:7c on br-client
Sun Nov 27 18:56:47 2016 daemon.info l3roamd[871]: event 60
Sun Nov 27 18:56:47 2016 daemon.info l3roamd[871]: client0: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:56:47 2016 daemon.info hostapd: client0: STA 00:18:de:24:c6:7c IEEE 802.11: authenticated
Sun Nov 27 18:56:47 2016 daemon.info hostapd: client0: STA 00:18:de:24:c6:7c IEEE 802.11: associated (aid 1)
Sun Nov 27 18:56:47 2016 daemon.info l3roamd[871]: event 60
Sun Nov 27 18:56:47 2016 kern.warn kernel: [ 999.320000] REJECT(src client)IN=br-client OUT= MAC=ff:ff:ff:ff:ff:ff:00:18:de:24:c6:7c:08:00 SRC=0.0.0.0 DST=255.255.255.255 LEN=328 TOS=0x10 PREC=0x00 TTL=128 ID=0 PROTO=UDP SPT=68 DPT=67 LEN=308
Sun Nov 27 18:56:48 2016 daemon.info l3roamd[871]: client0: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)
Sun Nov 27 18:56:48 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 (995.255729510)
Sun Nov 27 18:56:48 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff20:92a2
Sun Nov 27 18:56:48 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:56:48 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE
Sun Nov 27 18:56:50 2016 kern.warn kernel: [ 1001.860000] REJECT(src client)IN=br-client OUT= MAC=ff:ff:ff:ff:ff:ff:00:18:de:24:c6:7c:08:00 SRC=0.0.0.0 DST=255.255.255.255 LEN=328 TOS=0x10 PREC=0x00 TTL=128 ID=0 PROTO=UDP SPT=68 DPT=67 LEN=308
Sun Nov 27 18:56:51 2016 daemon.info l3roamd[871]: Add Address: fe80::218:deff:fe24:c67c
Sun Nov 27 18:56:52 2016 daemon.info l3roamd[871]: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:56:53 2016 daemon.info l3roamd[871]: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)
Sun Nov 27 18:56:53 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 (1000.256491255)
Sun Nov 27 18:56:53 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff20:92a2
Sun Nov 27 18:56:53 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:56:53 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE
Sun Nov 27 18:56:56 2016 kern.warn kernel: [ 1008.210000] REJECT(src client)IN=br-client OUT= MAC=ff:ff:ff:ff:ff:ff:00:18:de:24:c6:7c:08:00 SRC=0.0.0.0 DST=255.255.255.255 LEN=328 TOS=0x10 PREC=0x00 TTL=128 ID=0 PROTO=UDP SPT=68 DPT=67 LEN=308
Sun Nov 27 18:56:57 2016 daemon.info l3roamd[871]: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:56:58 2016 daemon.info l3roamd[871]: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)
Sun Nov 27 18:56:58 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 (1005.257325825)
Sun Nov 27 18:56:58 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff20:92a2
Sun Nov 27 18:56:58 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:56:58 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE
Sun Nov 27 18:57:00 2016 daemon.info fastd[1597]: resolving host gw02.babel.ffm.freifunk.net' for peer <mesh_vpn_backbone_peer_fastd2>... Sun Nov 27 18:57:00 2016 daemon.info fastd[1597]: resolving host gw02.babel.ffm.freifunk.net' failed: Name or service not known
Sun Nov 27 18:57:02 2016 daemon.info l3roamd[871]: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:57:03 2016 daemon.info l3roamd[871]: event 60
Sun Nov 27 18:57:03 2016 daemon.info l3roamd[871]: client0: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)
Sun Nov 27 18:57:03 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 (1010.258089745)
Sun Nov 27 18:57:03 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff20:92a2
Sun Nov 27 18:57:03 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:57:03 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE
Sun Nov 27 18:57:04 2016 daemon.info l3roamd[871]: Got packet to 2a06:8187:fbab:2:218:deff:fe24:c67c
Sun Nov 27 18:57:04 2016 daemon.info l3roamd[871]: Looking for 2a06:8187:fbab:2:218:deff:fe24:c67c
Sun Nov 27 18:57:04 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff24:c67c
Sun Nov 27 18:57:04 2016 daemon.info l3roamd[871]: Got packet to 2a06:8187:fbab:2:218:deff:fe24:c67c
Sun Nov 27 18:57:04 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:218:deff:fe24:c67c
Sun Nov 27 18:57:04 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:218:deff:fe24:c67c changes from INACTIVE to ACTIVE
Sun Nov 27 18:57:07 2016 daemon.info l3roamd[871]: Checking Client 00:18:de:24:c6:7c (active, br-client/7)
Sun Nov 27 18:57:07 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:218:deff:fe24:c67c (1015.826378795)
Sun Nov 27 18:57:07 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff24:c67c
Sun Nov 27 18:57:07 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:218:deff:fe24:c67c
Sun Nov 27 18:57:07 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:218:deff:fe24:c67c changes from ACTIVE to ACTIVE
Sun Nov 27 18:57:08 2016 daemon.info l3roamd[871]: Checking Client 9c:eb:e8:20:92:a2 (active, br-client/7)
Sun Nov 27 18:57:08 2016 daemon.info l3roamd[871]: ACTIVE 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 (1015.258922520)
Sun Nov 27 18:57:08 2016 daemon.info l3roamd[871]: Send NS to ff02::1:ff20:92a2
Sun Nov 27 18:57:08 2016 daemon.info l3roamd[871]: Add Address: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2
Sun Nov 27 18:57:08 2016 daemon.info l3roamd[871]: 2a06:8187:fbab:2:9eeb:e8ff:fe20:92a2 changes from ACTIVE to ACTIVE

In order to receive responses to claims l3roamd needs to know its unicast IP address. This IP address must be sent along with claims.

• re-trigger ND NS after a timeout (e.g. 15 minutes)
• remove stale client and routes
• send intercom packets three times, with 1s delay

Basically, we'd want to merge two client entries like this. A client entry contains:

• the client's MAC address
• timestamp when this client was last discovered
• a list of IP addresses for that client, each with a last seen time

We need to merge it like this:

• timestamp = max(timestamp_a, timestamp_b)
• for each entry in ip_list_b check if it is in ip_list_a. if yes, update timestamp to max, else add entry as is

The idea would be that a node stores information about its clients. Other nodes can request that information. Multiple nodes may respond and the requesting node may already know a few IP addresses for the client. Upon receiving responses, the node would then combine them.

• response (clientinfo) is sent using unicast and TTL = 1
• After combining entries routes need to be updated. It may be necessary to derive a list of removed and added entries from the operation.

intercom_packet_info should indicate whether the sending node was the previous owner of the client to indicate a successful handover.

As layed out in https://draic.info/2016/04/10/babel-in-gluon.html RAs should be managed a by a "client prefix daemon" instead of l3roamd.

• There should be a config file.
• There should be a command interface.
• Both share the same set of commands. The config file is, essentially, a script.

At the very least, these commands are required:

• attach-mesh-interface
• detach-mesh-interface
• attach-client-interface
• detach-client-interface
• add-prefix
• remove-prefix
• set-export-table

Ist eigentlich ähnlich des aktuellen claim pakets.

In case of no response a claim should be tried up to three times, each after a short delay of about 1s if no response is received. Use the relinquished flag to determine when to stop.