iptables -I POSTROUTING -t mangle -o eth0 -p tcp -m length --length :64 -j MARK --set-mark 10
iptables v1.4.21: Couldn't load match `length':No such file or directory
lsmod:
act_ipt 2432 0
act_mirred 2336 0
act_police 3168 0
act_skbedit 1600 0
cfg80211 217747 3 rt2x00lib
cls_basic 3024 0
cls_flow 5136 0
cls_fw 3488 2
cls_route 4576 0
cls_tcindex 4256 0
cls_u32 6256 0
compat 10610 5 rt2800soc
compat_xtables 571 0
crc_ccitt 1019 2 ppp_async
crc_itu_t 1019 0
dwc2 48407 1 dwc2_platform
dwc2_platform 1888 0
eeprom_93cx6 1807 1 rt2800pci
ehci_hcd 31516 1 ehci_platform
ehci_platform 3744 0
em_cmp 800 0
em_meta 4528 0
em_nbyte 720 0
em_text 1424 0
em_u32 576 0
gpio_button_hotplug 6064 0
ip6_tables 9297 3 ip6table_raw
ip6t_REJECT 1184 2
ip6table_filter 608 1
ip6table_mangle 1120 1
ip6table_raw 576 1
ip_set 21412 16 xt_set
ip_set_bitmap_ip 6768 0
ip_set_bitmap_ipmac 6544 0
ip_set_bitmap_port 6000 0
ip_set_hash_ip 17072 1
ip_set_hash_ipmark 17168 0
ip_set_hash_ipport 17728 0
ip_set_hash_ipportip 18528 0
ip_set_hash_ipportnet 23856 0
ip_set_hash_mac 8656 0
ip_set_hash_net 20896 0
ip_set_hash_netiface 22800 0
ip_set_hash_netnet 23856 0
ip_set_hash_netport 22544 0
ip_set_hash_netportnet 25008 0
ip_set_list_set 7376 0
ip_tables 9501 4 iptable_nat
ipt_ECN 1392 0
ipt_MASQUERADE 656 1
ipt_REJECT 912 0
iptable_filter 672 1
iptable_mangle 928 1
iptable_nat 768 1
iptable_raw 640 1
leds_gpio 2896 0
mac80211 392704 5 rt2800lib
mt76pci 41582 0
nf_conntrack 47963 13 nf_nat_ipv4
nf_conntrack_ipv4 4720 2
nf_conntrack_ipv6 5024 3
nf_conntrack_rtcache 2448 0
nf_defrag_ipv4 806 1 nf_conntrack_ipv4
nf_defrag_ipv6 9031 1 nf_conntrack_ipv6
nf_log_common 2399 2 nf_log_ipv4
nf_log_ipv4 3280 0
nf_log_ipv6 3424 0
nf_nat 9163 5 nf_nat_ipv4
nf_nat_ipv4 3761 1 iptable_nat
nf_nat_masquerade_ipv4 1420 1 ipt_MASQUERADE
nf_reject_ipv4 1795 1 ipt_REJECT
nf_reject_ipv6 2087 1 ip6t_REJECT
nfnetlink 4027 1 ip_set
nls_base 5008 1 usbcore
ohci_hcd 21951 1 ohci_platform
ohci_platform 3248 0
ppp_async 6352 0
ppp_generic 20690 3 pppoe
pppoe 8144 0
pppox 1354 1 pppoe
rt2800lib 91760 3 rt2800soc
rt2800mmio 6338 2 rt2800soc
rt2800pci 3968 0
rt2800soc 2496 0
rt2x00lib 34111 7 rt2800soc
rt2x00mmio 1904 3 rt2800soc
rt2x00pci 1506 1 rt2800pci
rt2x00soc 1202 1 rt2800soc
sch_codel 4112 0
sch_dsmark 3632 0
sch_fq 5936 0
sch_gred 6384 0
sch_hfsc 13344 0
sch_htb 12576 1
sch_ingress 944 0
sch_pie 4016 0
sch_prio 3232 0
sch_red 4480 0
sch_sfq 8176 3
sch_tbf 5104 0
sch_teql 3696 0
slhc 4395 1 ppp_generic
usb_common 1740 2 dwc2_platform
usbcore 117268 6 dwc2_platform
x_tables 10901 45 ipt_REJECT
xt_CLASSIFY 576 0
xt_CT 2352 0
xt_DSCP 1536 0
xt_HL 1296 0
xt_LOG 768 0
xt_NETMAP 1248 0
xt_REDIRECT 1152 0
xt_TCPMSS 2704 2
xt_comment 480 36
xt_connbytes 1520 0
xt_connlimit 3440 0
xt_connmark 1040 0
xt_conntrack 2144 4
xt_dscp 1008 0
xt_ecn 1296 0
xt_geoip 2896 0
xt_helper 880 0
xt_hl 800 0
xt_id 480 0
xt_length 704 0
xt_limit 992 19
xt_mac 624 0
xt_mark 672 2
xt_multiport 1200 0
xt_nat 1152 0
xt_recent 6432 0
xt_set 5712 0
xt_state 688 0
xt_statistic 784 0
xt_tcpmss 1040 0
xt_tcpudp 1760 15
xt_time 1648 0
ls modules.d
20-cfg80211 50-mt76 ipt-conntrack lib-crc-ccitt nfnetlink
20-eeprom-93cx6 50-usb-ohci ipt-conntrack-extra lib-crc-itu-t ppp
20-usb-core 54-usb-dwc2 ipt-core nf-conntrack pppoe
30-gpio-button-hotplug 60-leds-gpio ipt-geoip nf-conntrack6 rt2800-pci
40-usb2 70-sched-core ipt-ipopt nf-ipt rt2800-soc
42-ip6tables 73-sched ipt-nat nf-ipt6 rt2x00-pci
49-ipt-ipset ipt-compat-xtables ipt-nat-extra nf-nat
This is CC, self-compiled from trunk.