[squid-users] tcp_outgoing_address and ICAP server

[Marcus Kool]

On 01/24/2015 11:24 PM, Amos Jeffries wrote:
> On 25/01/2015 9:39 a.m., Marcus Kool wrote:
>>
>>
>> On 01/24/2015 10:15 AM, Amos Jeffries wrote:
>>> On 22/01/2015 10:11 a.m., Marcus Kool wrote:
>>>> I am using Squid 3.4.9 and have an issue with tcp_outgoing_address.
>>>>
>>>> The Squid server is connceted to the internet with multiple NICs and
>>>> uses
>>>>      tcp_outgoing_address a.public.IP.address
>>>>
>>>> and also want to use an ICAP server on the same host using
>>>>
>>>> icap_service  reqmod_urlfilterdb   reqmod_precache
>>>> icap://a.local.ip.address:1344/reqmod_icapd  bypass=off  routing=on
>>>> on-overload=wait ipv6=off
>>>>
>>>> It seems that Squid binds the connection to the ICAP server the same way
>>>> it binds
>>>> connections to webservers using the rule with tcp_outgoing_address
>>>> and that it not desired nor workable.
>>>>
>>>> I tried
>>>>
>>>> acl myicaphost dst a.local.ip.address
>>>> tcp_outgoing_address a.public.IP.address !myicaphost
>>>>
>>>> but Squid issues the following errors:
>>>> 2015/01/21 21:58:32 kid1| WARNING: myicaphost ACL is used in context
>>>> without an HTTP request. Assuming mismatch.
>>>> 2015/01/21 21:58:32 kid1| commBind: Cannot bind socket FD 10 to
>>>> XX.XX.XX.XX: (99) Cannot assign requested address
>>>> 2015/01/21 21:58:32 kid1| essential ICAP service is down after an
>>>> options fetch failure: icap://XX.XX.XX.XX:1344/reqmod_icapd [down,!opt]
>>>>
>>>> So the question is how to send web traffic over a specific NIC and
>>>> traffic to the ICAP server over an other (default?) NIC ?
>>>
>>>
>>> Please try the attached patch against Squid-3.4. It should make your
>>> config work.
>>>
>>> Amos
>>
>> Thank you for the patch.
>> It resolves 1 issue: there is no longer the warning
>>     WARNING: myicaphost ACL is used in context without an HTTP request.
>> Assuming mismatch.
>>
>> But the binding to the wrong NIC with the external IP still happens:
>>
>> 2015/01/24 17:19:48.027 kid1| Xaction.cc(133) openConnection:
>> Adaptation::Icap::OptXact opens connection to 10.10.0.6:1344
>> 2015/01/24 17:19:48.027 kid1| AsyncCall.cc(18) AsyncCall: The AsyncCall
>> Adaptation::Icap::Xaction::noteCommConnected constructed, this=0x1d9d7e0
>> [call53]
>> 2015/01/24 17:19:48.027 kid1| comm.cc(549) comm_openex: comm_openex:
>> Attempt open socket for: a.public.IP.address
>> 2015/01/24 17:19:48.027 kid1| comm.cc(590) comm_openex: comm_openex:
>> Opened socket local=a.public.IP.address remote=[::] FD 10 flags=1 :
>> family=2, type=1, protocol=6
>>
>> The firewall and routing was changed to allow traffic from the external
>> IP to
>> the internal IP so for us the urgency of the issue is low, but
>> the binding remains on the external IP despite the ACL saying not to do it.
>
> Aha, conceptual problem.
>
> tcp_outgoing_address does not forbid things. There is no "allow/deny"
> action, just a set-IP action. It either sets the IP or it leaves it alone.

Do you agree that the binding should not take place if a socket
is created with a destination address 'myicaphost' ?  The myicaphost is
10.10.0.6 and the comm debug output above shows that the socket *is* bound.

> Your rule sets the IP when the dst is non-myicaphost. So what
> tcp_outgoing_address rule or OS level routing rule matches when it *is*
> myicaphost?

Sorry, I don't know which routing decision is taken. All I know is that
the routing has been changed to make the connection to the ICAP server work.

I tried to show with the comm debug output that the connection to the
ICAP server (10.10.0.6) is still bound.  I replaced the public IP address
with "a.public.IP.address"  (I do not want to show the real IP but
it is definitely a public IP address).

> Amos

Thanks
Marcus