我在主机中使用 IEC61850_SV 协议传输一系列测试数据包，如下所示：
01 0C CD 04 00 03 00 0C CD 04 00 00 81 00 80 01 88 BA 40 03 01 24 00 00 00 00 60 82 01 18 80 01 01 A2 82 01 11 30 82 01 0D 80 1B 50 53 53 43 36 30 31 4D 55 53 56 2F 4C 4C 4E 30 24 4D 53 24 4D 53 56 43 42 30 31 82 02 0B C6 83 04 00 00 00 01 85 01 00 87 81 E0 00 00 00 FA 00 00 00 00 FF EC C5 D9 00 00 00 00 FF EC C5 D9 00 00 00 00 00 12 19 12 00 00 00 00 00 12 19 12 00 00 00 00 00 01 21 24 00 00 00 00 00 01 21 24 00 00 00 00 EC C5 D9 00 00 00 00 00 12 19 12 00 00 00 00 00 01 21 24 00 00 00 00 FF 90 FD E8 00 00 00 00 FF 90 FD E8 00 00 00 00 00 68 7C DF 00 00 00 00 00 68 7C DF 00 00 00 00 00 06 85 39 00 00 00 00 00 06 85 39 00 00 00 00 FF 90 FD E8 00 00 00 00 FF 90 FD E8 00 00 00 00 00 00 00 0F 00 00 00 00 00 00 00 0F 00 00 00 00 FF 90 FD E8 00 00 00 00 FF 90 FD E8 00 00 00 00 00 68 7C DF 00 00 00 00 00 68 7C DF 00 00 00 00 00 06 85 39 00 00 00 00 00 06 85 39 00 00 0 0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Num 000001
Length 314
Capture Length 310
time difference 0.000000000 sec
ethernet - II [0/14]
target 01:0C:CD:04:00:03 [0/6]
source 00:0C:CD:04:00:00 [6/6]
protocal 0x8100 (VLAN) [12/2]
802.1Q vlan protocal [14/4]
Label [14/2]
User priority 100. .... [14/1] 0x00E0
CFI ...0 .... [14/1] 0x0010
VlAN num .... 0000 0000 0001 (1) [14/2] 0x0FFF
protocal 0x88ba (IEC61850_SV) [16/2]
IEC61850 sample value [18/21]
Id 0x4003 [18/2]
length 292 [20/2]
reserved bit1 0x0 [22/2]
reserved bit2 0x0 [24/2]
savPdu [30/0]
application service data units 1 [32/1]
Sequence ASDU [37/0]
ASDU [37/0]
Additional data [39/271]
bytes 271 bytes [39/271]
FCs
FCs 0x2F0CA2EA
然后我在目标机器中使用 tcpdump 来捕获数据包。日志显示如下：
09:06:02.562846 00:0c:cd:04:00:00 (oui Unknown) > 01:0c:cd:04:00:03 (oui Unknown), 802.1Q, length 310:
09:06:02.574656 00:0c:cd:04:00:00 (oui Unknown) > 01:0c:cd:04:00:03 (oui Unknown), 802.1Q, length 310:
09:06:02.589684 00:0c:cd:04:00:00 (oui Unknown) > 01:0c:cd:04:00:03 (oui Unknown), 802.1Q, length 310:
09:06:02.605706 00:0c:cd:04:00:00 (oui Unknown) > 01:0c:cd:04:00:03 (oui Unknown), 802.1Q, length 310:
09:06:02.620610 00:0c:cd:04:00:00 (oui Unknown) > 01:0c:cd:04:00:03 (oui Unknown), 802.1Q, length 310:
09:06:02.635996 00:0c:cd:04:00:00 (oui Unknown) > 01:0c:cd:04:00:03 (oui Unknown), 802.1Q, length 310:
09:06:02.650857 00:0c:cd:04:00:00 (oui Unknown) > 01:0c:cd:04:00:03 (oui Unknown), 802.1Q, length 310:
09:06:02.665517 00:0c:cd:04:00:00 (oui Unknown) > 01:0c:cd:04:00:03 (oui Unknown), 802.1Q, length 310:
09:06:02.680210 00:0c:cd:04:00:00 (oui Unknown) > 01:0c:cd:04:00:03 (oui Unknown), 802.1Q, length 310:
09:06:02.695342 00:0c:cd:04:00:00 (oui Unknown) > 01:0c:cd:04:00:03 (oui Unknown), 802.1Q, length 310:
10 packets captured
10 packets received by filter
0 packets dropped by kernel
10 packets dropped by interface
奇怪的是所有 vlan 协议数据包都被接口丢弃。然后我使用vconfig add eth0 1添加eth0.1端口，并使用eth0.1接收数据包，它显示数据包已正确接收。
因为其他数据包（如 ARP）将被接口正确接收。我想知道为什么带有vlan协议的数据包会被接口自动丢弃，而不是被接口接收，但无法被网络层解析。同样的，数据链路层直接丢弃它，内核没有得到任何数据。
cat /proc/net/dev
Inter-| Receive | Transmit
face |bytes packets errs drop fifo frame compressed multicast|bytes packets errs drop fifo colls carrier compressed
eth1: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
lo: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
eth0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
除了添加vlan之外，内核还有什么办法可以直接接收这些数据包吗？