为什么关闭网卡的 RX offload 不起作用？

[lysShub]

raw socket 读取到 Reassemble 不好处理，我把 offload 都关了：

Features for eth0:
rx-checksumming: on [fixed]
tx-checksumming: on
        tx-checksum-ipv4: off [fixed]
        tx-checksum-ip-generic: on
        tx-checksum-ipv6: off [fixed]
        tx-checksum-fcoe-crc: off [fixed]
        tx-checksum-sctp: off [fixed]
scatter-gather: on
        tx-scatter-gather: on
        tx-scatter-gather-fraglist: off [fixed]
tcp-segmentation-offload: off
        tx-tcp-segmentation: off
        tx-tcp-ecn-segmentation: off
        tx-tcp-mangleid-segmentation: off
        tx-tcp6-segmentation: off
udp-fragmentation-offload: off
generic-segmentation-offload: off
generic-receive-offload: off
large-receive-offload: off [fixed]
rx-vlan-offload: off [fixed]
tx-vlan-offload: off [fixed]
ntuple-filters: off [fixed]
receive-hashing: off [fixed]
highdma: on [fixed]
rx-vlan-filter: on [fixed]
vlan-challenged: off [fixed]
tx-lockless: off [fixed]
netns-local: off [fixed]
tx-gso-robust: on [fixed]
tx-fcoe-segmentation: off [fixed]
tx-gre-segmentation: off [fixed]
tx-gre-csum-segmentation: off [fixed]
tx-ipxip4-segmentation: off [fixed]
tx-ipxip6-segmentation: off [fixed]
tx-udp_tnl-segmentation: off [fixed]
tx-udp_tnl-csum-segmentation: off [fixed]
tx-gso-partial: off [fixed]
tx-sctp-segmentation: off [fixed]
tx-esp-segmentation: off [fixed]
tx-udp-segmentation: off [fixed]
fcoe-mtu: off [fixed]
tx-nocache-copy: off
loopback: off [fixed]
rx-fcs: off [fixed]
rx-all: off [fixed]
tx-vlan-stag-hw-insert: off [fixed]
rx-vlan-stag-hw-parse: off [fixed]
rx-vlan-stag-filter: off [fixed]
l2-fwd-offload: off [fixed]
hw-tc-offload: off [fixed]
esp-hw-offload: off [fixed]
esp-tx-csum-hw-offload: off [fixed]
rx-udp_tunnel-port-offload: off [fixed]
tls-hw-tx-offload: off [fixed]
tls-hw-rx-offload: off [fixed]
rx-gro-hw: off [fixed]
tls-hw-record: off [fixed]

无论是 tcpdump ，还是 raw/eth socket 都会读取到大于 mtu 的 tcp 数据包, 一时整的我没辙了。

相关资料： https://v2ex.com/t/917581
https://github.com/wangyu-/udp2raw/issues/226
https://www.v2ex.com/t/1053423

[1423]

之前研究过,包括 UDP 转发, 伪装 TCP. 都很容易碰到这类问题

[LGA1150]

提供内核版本和网卡型号，我查一下代码

[loyfan]

这是虚机还是物理机？
虚机网卡是特殊的

[lysShub]

@LGA1150
云主机网卡似乎查不到 Red Hat, Inc Virtio network device

内核 4.19.0-5-amd64

[lysShub]

@loyfan 对就是虚拟机，bwg 的，我试了下阿里云的是有效的

[LGA1150]

KVM 的虚拟机，接收报文先经过宿主的网卡，我觉得只能关闭宿主的 GRO 功能才可以生效

[lysShub]

@LGA1150 嗯 想也是，我现在打算手动给它拆分开，真麻烦！