Hi all,
I am doing some tests on ICMP_REDIRECT messages and found that I never receive
the first ICMP_REDIRECT message, but the following REDIRECT messages was normal.
My test environment as follow:
three pc:
PC A:
IP: 192.168.0.1 MAC: HW:0A
PC B:
IP: 192.168.0.2 MAC: HW:0B
module nf_nat loaded and at least one rule in nat table(rule content not concern)
PC C:
IP: 192.168.0.3 MAC: HW:0C
enable ip forwarding on PC B:
# echo 1 > /proc/sys/net/ipv4/ip_forward
add a static arp on PC A:
# arp -s 192.168.0.3 HW:0B
ping 192.168.0.3 on PC A:
# ping -c1 192.168.0.3
I expect that PC A will receive a ICMP_REDIRECT message from PC B, but nothing
received.
ping three times 192.168.0.3 on PC A:
# ping -c3 192.168.0.3
PC A got two ICMP_REDIRECT messages from PC B, the first one missing.
After some code search, I found in function nf_nat_icmp_reply_translation() the first
ICMP_REDIRECT message was droped because the ct->status is not IPS_NAT_DONE_MASK.
Does anyone has some suggestion?