Batman V support

[grische]

The current implementation relies on Batman IV (and it's TQ value) and transmits invalid VPN values for Batman V.

I tried, but failed, to fix this with https://github.com/freifunkMUC/node-whisperer/commits/batman-v/ based on

• our patchset: https://github.com/freifunkMUC/gluon/commits/v2023.2.x-batmanv/
• together with some inspiration from batctl how to handle IV+V: https://github.com/open-mesh-mirror/batctl

[T-X]

What failed exactly? How do such invalid VPN values look like?

[grische]

I found the issue, I used NLM_F_DUMP on .doit but it requires a .dumpit:

	{
		.cmd = BATADV_CMD_GET_MESH,
		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
		/* can be retrieved by unprivileged users */
		.doit = batadv_netlink_get_mesh,
		.internal_flags = BATADV_FLAG_NEED_MESH,
	},

https://github.com/torvalds/linux/blob/8bb7eca972ad531c9b149c0a51ab43a417385813/net/batman-adv/netlink.c#L1365

The following patch got it working for me:

diff --git a/src/batadv.c b/src/batadv.c
index c974f3e..6536a3f 100644
--- a/src/batadv.c
+++ b/src/batadv.c
@@ -221,7 +221,7 @@ int get_algoname_netlink(char *algoname, size_t algoname_len) {
        int ret;

        ret = batadv_genl_query("bat0", BATADV_CMD_GET_MESH,
-                                                       get_algoname_netlink_cb, NLM_F_DUMP,
+                                                       get_algoname_netlink_cb, 0,
                                                        &opts.query_opts);
        if (ret < 0) {
                log_error("get_algoname_netlink() query BATADV_CMD_GET_MESH failed with %d", ret);