[ovs-discuss] first ip fragment packet doesn't match the L4 field

Huanle Han hanxueluo at gmail.com
Sun Nov 8 15:54:43 UTC 2015


Hi,
When I look into the function 'rule_dpif_lookup_from_table', I find it set
0 to tp_src and tp_dst for the ip fragment flow, before looking up the rule
in table.
It make sense for the later fragments because they have no L4 information.
But why do it for the first fragment ?

In below case, first fragment flow matches the second flow entry rather
than the first one.

root at ubuntu:~# ovs-ofctl dump-flows br
NXST_FLOW reply (xid=0x4):
    cookie=0x0, duration=23.387s, table=0, n_packets=0, n_bytes=0,
idle_age=23, priority=10,udp,in_port=2,*nw_frag=first*,tp_dst=8001
actions=mod_tp_dst:8002,output:1
    cookie=0x0, duration=8.432s, table=0, n_packets=0, n_bytes=0,
idle_age=8, priority=5,udp,in_port=2,tp_dst=8001
actions=mod_tp_dst:8003,output:1
    cookie=0x0, duration=36.275s, table=0, n_packets=57, n_bytes=59184,
idle_age=0, priority=0 actions=NORMAL
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