Hi Xiaopeng,
If you disable flooding in a BD then it will not forward broadcast nor
multicast (BM) packets, because there is nothing else to do with such packets
other than flood. The l2fib is not consulted for BM packets, so if you added a
static entry for a BM address it won’t be used. The packet in the trace was
broadcast, hence it was dropped.
/neale
From: vpp-dev@lists.fd.io <vpp-dev@lists.fd.io> on behalf of Xiaopeng Bai via
lists.fd.io <baixiaopeng=ekean...@lists.fd.io>
Date: Thursday, 12 August 2021 at 06:09
To: vpp-dev@lists.fd.io <vpp-dev@lists.fd.io>
Subject: [vpp-dev] some confusions about l2 forward and flood
Hi everyone!
When I was testing the bridge function，everything worked fine with the
following configuration：
BD-ID Index BSN Age(min) Learn Forwrd UU-Flood Flood
ARP-Term ARP-ufwd BVI-Intf
1 1 0 off off on flood on
off off N/A
But when i disabled bridge-domain flood and add static mac for mac table, the
bridge-domain didn't forward packets and show errors likes below:
Packet 1
00:02:40:993565: dpdk-input
GbitEth0/0/2 rx queue 0
buffer 0x4b4e78: current data 0, length 60, buffer-pool 0, ref-count 1,
totlen-nifb 0, trace handle 0x1000000
ext-hdr-valid
l4-cksum-computed l4-cksum-correct
PKT MBUF: port 1, nb_segs 1, pkt_len 60
buf_len 2176, data_len 60, ol_flags 0x180, data_off 128, phys_addr
0x91f39e80
packet_type 0x0 l2_len 0 l3_len 0 outer_l2_len 0 outer_l3_len 0
rss 0x0 fdir.hi 0x0 fdir.lo 0x0
Packet Offload Flags
PKT_RX_IP_CKSUM_GOOD (0x0080) IP cksum of RX pkt. is valid
PKT_RX_L4_CKSUM_GOOD (0x0100) L4 cksum of RX pkt. is valid
ARP: c8:d3:ff:ba:51:2b -> ff:ff:ff:ff:ff:ff
request, type ethernet/IP4, address size 6/4
c8:d3:ff:ba:51:2b/192.168.0.200 -> 00:00:00:00:00:00/192.168.0.111
00:02:40:993578: flowprobe-l2
FLOWPROBE[IP4]: rx_sw_if_index 0, tx_sw_if_index 0, timestamp 0, size 0
00:02:40:993588: ethernet-input
ARP: c8:d3:ff:ba:51:2b -> ff:ff:ff:ff:ff:ff
00:02:40:993592: l2-input
l2-input: sw_if_index 2 dst ff:ff:ff:ff:ff:ff src c8:d3:ff:ba:51:2b
00:02:40:993595: feature-bitmap-drop
feat_bitmap_drop: feature bitmap 0x00000001
00:02:40:993597: error-drop
rx:GbitEth0/0/2
00:02:40:993599: drop
feature-bitmap-drop: L2 feature forwarding disabled
Why l2_input dropped packets? I browsed the l2_input.c codes and find some
codes like this:
/* Disable bridge forwarding (flooding will execute instead if not xconnect) */
feat_mask &= ~(L2INPUT_FEAT_FWD |
L2INPUT_FEAT_UU_FLOOD |
L2INPUT_FEAT_UU_FWD | L2INPUT_FEAT_GBP_FWD);
Some confusions are why Disable bridge forwarding and instead with flooding?
some suggestions are appreciated！
Best Regeards,
Xiaopeng
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