PF states degrade?

Thu Feb 6 16:59:12 UTC 2014

On 2/6/2014 1:14 AM, Dennis Yusupoff wrote:
> Good day.
>
> We had started to testing FreeBSD 10.0 in production (pf nat, ipfw
> pipes, ng_netflow) with setting (sysctl,pf.conf,ipfw.conf etc) from
> similar rocksolid 9.0-STABLE.
> Server has worked fine for a ~5 days and then suddenly stop forwarding
> traffic from clients. What was a quite unexpecting is how it had
> happening. Traffic from customers...dissappear (seen in tcpdump) from
> LAN interface in ~10 seconds after _connection_ (NAT translation state
> has been created?) has been started, with pf log (when set "log debug
> loud" in pf.conf) strange record appears in that moment, like that:
>
> 10.53.80.224 nat'ed in 109.71.177.147, http connection to 213.180.204.183:
> ---
> Feb  5 20:41:21 nata2 kernel: pf: State failure on: 1       | 5
> Feb  5 20:41:21 nata2 kernel: pf: BAD state: TCP out wire:
> 213.180.204.183:80
> Feb  5 20:41:21 nata2 kernel: 109.71.177.147:50114 stack:
> 213.180.204.183:80 10.53.80.224:50114 [lo=1997798965 high=1997799354
> win=2772 modulator=0]
> Feb  5 20:41:21 nata2 kernel: [lo=864623348 high=864624718 win=389
> modulator=0] 4:4 A seq=864739382 (864739382) ack=1997798965 len=1398
> ackskew=0 pkts=3:2 dir=in,rev
> ---
> Full log there: http://pastebin.com/CQ78JyJe
>
> Disabling/enabling PF - no difference (except, indeed, nat stop working).
>
> After all attempts we did "pfctl -d" and setup ipfw nat for that
> customer. All has work fine! So we believe in uknown (for us) problem
> related to PF and it state work.
>
> PF rules and settings:
>
> ---
> ext_if="lagg0"
> int_if_1="vlan22"
> int_if_2="vlan21"
>
> dst_nat1="109.71.177.128/25"
> dst_nat2="109.71.177.0/25"
>
> table <src-nat> persist file "/etc/pf.src-nat"
> table <our-nets> const { 80.249.176.0/20, 93.92.192.0/21,
> 109.71.176.0/21, 217.119.16.0/20 }
> table <allowed-spammers> persist { 10.52.249.24 }
>
> table <always_allowed_dst> persist { 84.204.97.154, 213.180.204.32,
> 195.95.218.31, 195.95.218.30 }
>
> set limit { states 1000000, frags 80000, src-nodes 100000, table-entries
> 500000}
> set state-policy if-bound
> set optimization aggressive
> set debug urgent
> set ruleset-optimization profile
> set timeout { frag 10, tcp.established 3600, src.track 30 }
> set block-policy drop
> set require-order no
>
>
> set skip on {lo0, em0, pfsync0}
>
>
> table <spammers> persist
> pass in quick on $int_if_1 proto tcp from <allowed-spammers> to any port
> smtp flags S/SAFR keep state
> pass in quick on $int_if_2 proto tcp from <allowed-spammers> to any port
> smtp flags S/SAFR keep state
> pass in on $int_if_1 proto tcp from any to any port smtp flags S/SAFR
> keep state \
>                  (max-src-conn 15, max-src-conn-rate 15/30, overload
> <spammers> flush global)
>                  block return-icmp (host-prohib) log quick proto tcp from
> <spammers> to any port smtp
>
> pass in on $int_if_2 proto tcp from any to any port smtp flags S/SAFR
> keep state \
>                  (max-src-conn 15, max-src-conn-rate 15/30, overload
> <spammers> flush global)
>                  block return-icmp (host-prohib) log quick proto tcp from
> <spammers> to any port smtp
>
>
> pass in quick on $int_if_1 all no state allow-opts tag NAT1 label "$nr:NAT1"
> pass in quick on $int_if_2 all no state allow-opts tag NAT2 label "$nr:NAT2"
>
> binat-anchor "binat"
> load anchor "binat" from "/etc/pf.anchor.binat"
> nat-anchor "ftp-proxy/*"
> rdr-anchor "ftp-proxy/*"
> rdr pass on $int_if_1 proto tcp from <src-nat> to any port 21 ->
> 127.0.0.1 port 8021
> rdr pass on $int_if_2 proto tcp from <src-nat> to any port 21 ->
> 127.0.0.1 port 8021
> rdr pass on $ext_if proto udp from 109.71.176.3 to 109.71.176.2 port
> 4784 -> 10.78.76.2 port 4784
>
> nat on $ext_if from <src-nat> to any tagged NAT1 -> $dst_nat1
> static-port source-hash #sticky-address
> nat on $ext_if from <src-nat> to any tagged NAT2 -> $dst_nat2
> static-port source-hash #sticky-address
> nat on $ext_if from any to <always_allowed_dst> -> $dst_nat1 static-port
> source-hash #sticky-address
>
> binat on $ext_if from 10.78.78.2 to any -> 93.92.199.252
>
> nat on $ext_if from 10.78.76.0/24 to any -> 109.71.176.2 static-port
> source-hash
> nat on $ext_if from 10.78.77.0/24 to any -> 93.92.199.254
> nat on $ext_if from 10.78.78.0/24 to any -> $dst_nat1 static-port
> source-hash
>
> anchor "ftp-proxy/*"
> pass out quick proto tcp from any to any port 21 no state
>
> pass quick on $ext_if proto gre all no state
> ---
>
> *P. S. Traffic start forwarding with pf only after server has been

Dennis,

Did you run out of pf state table entries? You can use pfctl to list the 
current limit and usage ...

INFO:
Status: Enabled for 14 days 19:48:29          Debug: Urgent

State Table                          Total             Rate
   current entries                        4
   searches                         2030427            1.6/s
   inserts                            64990            0.1/s
   removals                           64986            0.1/s

LIMITS:
states        hard limit    10000
src-nodes     hard limit    10000
frags         hard limit     5000
table-entries hard limit   200000

.. If that is the case, you can increase your state table size by 
inserting some configuration parameters at the top of your pf.conf file. 
For example ...

set limit states    50000
set limit src-nodes 50000
set limit frags     25000

-Matthew