net: ipv4: avoid mixed n_redirects and rate_tokens usage
Since commit c09551c6 ("net: ipv4: use a dedicated counter for icmp_v4 redirect packets") we use 'n_redirects' to account for redirect packets, but we still use 'rate_tokens' to compute the redirect packets exponential backoff. If the device sent to the relevant peer any ICMP error packet after sending a redirect, it will also update 'rate_token' according to the leaking bucket schema; typically 'rate_token' will raise above BITS_PER_LONG and the redirect packets backoff algorithm will produce undefined behavior. Fix the issue using 'n_redirects' to compute the exponential backoff in ip_rt_send_redirect(). Note that we still clear rate_tokens after a redirect silence period, to avoid changing an established behaviour. The root cause predates git history; before the mentioned commit in the critical scenario, the kernel stopped sending redirects, after the mentioned commit the behavior more randomic. Reported-by:Xiumei Mu <xmu@redhat.com> Fixes: 1da177e4 ("Linux-2.6.12-rc2") Fixes: c09551c6 ("net: ipv4: use a dedicated counter for icmp_v4 redirect packets") Signed-off-by:
Paolo Abeni <pabeni@redhat.com> Acked-by:
Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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