kernel: add a bridge feature for filtering BPDU packets on ports

[Andre Heider]

Sorry for the spam, last mail for now as I found some log entries that 
might be related (HEAD=6cd54254e4bbe7ed2b71c17cb2d54ad7b0bc2991):

kern.warn kernel: [   55.820638] netlink: 'iw': attribute type 302 has 
an invalid length.
kern.warn kernel: [   56.354160] netlink: 'iw': attribute type 302 has 
an invalid length.

<snip>

daemon.notice wpa_supplicant[2028]: mesh: MESH-PEER-CONNECTED $mac
kern.warn kernel: [   76.849584] ------------[ cut here ]------------
kern.warn kernel: [   76.852852] WARNING: CPU: 0 PID: 5298 at 
net/core/flow_dissector.c:975 __skb_flow_dissect+0x21c/0x1894
kern.warn kernel: [   76.862457] Modules linked in: ath9k ath9k_common 
xt_connlimit pppoe ppp_async nf_conncount iptable_nat ath9k_hw 
ath10k_pci ath10k_core ath xt_state xt_nat xt_helper xt_conntrack 
xt_connmark xt_connbytes xt_REDIRECT xt_MASQUERADE xt_CT wireguard pppox 
ppp_generic pl2303 nf_nat nf_conntrack_netlink nf_conntrack mac80211 
libchacha20poly1305 libblake2s ipt_REJECT ftdi_sio cfg80211 
ath9k_pci_owl_loader xt_time xt_tcpudp xt_tcpmss xt_statistic xt_recent 
xt_multiport xt_mark xt_mac xt_limit xt_length xt_hl xt_ecn xt_dscp 
xt_comment xt_TCPMSS xt_LOG xt_HL xt_DSCP xt_CLASSIFY usbserial slhc 
sch_cake poly1305_mips nf_reject_ipv4 nf_log_ipv4 nf_log_common 
nf_defrag_ipv6 nf_defrag_ipv4 libcurve25519_generic libblake2s_generic 
iptable_raw iptable_mangle iptable_filter ipt_ECN ip_tables crc_ccitt 
compat chacha_mips sch_tbf sch_ingress sch_htb sch_hfsc em_u32 cls_u32 
cls_tcindex cls_route cls_matchall cls_fw cls_flow cls_basic act_skbedit 
act_mirred act_gact drv_dsl_cpe_api ledtrig_usbport drv_mei_cpe
kern.warn kernel: [   76.863496]  xt_set x_tables ip_set_list_set 
ip_set_hash_netportnet ip_set_hash_netport ip_set_hash_netnet 
ip_set_hash_netiface ip_set_hash_net ip_set_hash_mac 
ip_set_hash_ipportnet ip_set_hash_ipportip ip_set_hash_ipport 
ip_set_hash_ipmark ip_set_hash_ip ip_set_bitmap_port ip_set_bitmap_ipmac 
ip_set_bitmap_ip ip_set nfnetlink ifb ip6_udp_tunnel udp_tunnel br2684 
atm zram zsmalloc drv_ifxos sha256_generic libsha256 seqiv 
jitterentropy_rng drbg hmac cmac dwc2 roles ohci_platform ohci_hcd 
fsl_mph_dr_of ehci_platform ehci_fsl ehci_hcd gpio_button_hotplug
kern.warn kernel: [   76.998750] CPU: 0 PID: 5298 Comm: sh Not tainted 
5.10.64 #0
kern.warn kernel: [   77.004303] Stack : 80a28218 00000000 00000000 
00000000 8079d544 00000000 00000001 80083264
kern.warn kernel: [   77.012650]         0000000c 00000000 00000000 
a4d9dc81 80c0bbc4 00000001 80c0bb58 a4d9dc81
kern.warn kernel: [   77.021006]         00000000 00000000 8076c9b0 
80c0ba00 ffffefff 00000000 00000000 ffffffea
kern.warn kernel: [   77.029362]         00000156 80c0ba08 80830000 
ffffffff 80830000 80000000 00000000 80770000
kern.warn kernel: [   77.037712]         00000009 80830000 00000000 
00000000 00000018 00000030 00000000 80a00000
kern.warn kernel: [   77.046074]         ...
kern.warn kernel: [   77.048506] Call Trace:
kern.warn kernel: [   77.050965] [<8000bf54>] show_stack+0x40/0x128
kern.warn kernel: [   77.055408] [<8035de84>] dump_stack+0x9c/0xcc
kern.warn kernel: [   77.059776] [<80030bd8>] __warn+0xc0/0x12c
kern.warn kernel: [   77.063841] [<80030cb4>] warn_slowpath_fmt+0x70/0xd8
kern.warn kernel: [   77.068817] [<804c7b90>] 
__skb_flow_dissect+0x21c/0x1894
kern.warn kernel: [   77.074122] [<804c9380>] __skb_get_hash+0x7c/0x128
kern.warn kernel: [   77.079043] [<82a3aa28>] 
ieee80211_schedule_txq+0x784/0xa24 [mac80211]
kern.warn kernel: [   77.085490]
kern.warn kernel: [   77.086994] ---[ end trace f966cd7c4a091c65 ]---

<snip>

daemon.notice hostapd: $bgnmaster: interface state COUNTRY_UPDATE->ENABLED
daemon.notice hostapd: $bgnmaster: AP-ENABLED
daemon.notice hostapd: $nacmaster: interface state COUNTRY_UPDATE->ENABLED
daemon.notice hostapd: $nacmaster: AP-ENABLED
daemon.notice netifd: Network device '$bgnmaster' link is up
daemon.notice netifd: Network device '$guestmaster' link is up
daemon.notice netifd: Interface 'guests' is enabled
daemon.notice netifd: Interface 'guests' is setting up now
daemon.notice netifd: Interface 'guests' is now up
daemon.notice netifd: Interface 'guests' has link connectivity
kern.info kernel: [   71.979551] br-lan: port 5($nacmaster) entered 
disabled state
daemon.notice netifd: radio0 (2821): command failed: Link has been 
severed (-67)
daemon.notice netifd: radio0 (2821): command failed: Link has been 
severed (-67)
kern.info kernel: [   72.905264] br-lan: port 7(mesh) entered blocking state
kern.info kernel: [   72.909227] br-lan: port 7(mesh) entered disabled state
kern.info kernel: [   72.915258] device mesh entered promiscuous mode