org.apache.catalina.valves
Class RemoteIpValve

java.lang.Object
  org.apache.catalina.valves.ValveBase
      org.apache.catalina.valves.RemoteIpValve

All Implemented Interfaces:

javax.management.MBeanRegistration, Contained, Valve

public class RemoteIpValve
extends ValveBase

Tomcat port of mod_remoteip, this valve replaces the apparent client remote IP address and hostname for the request with the IP address list presented by a proxy or a load balancer via a request headers (e.g. "X-Forwarded-For").

Another feature of this valve is to replace the apparent scheme (http/https) and server port with the scheme presented by a proxy or a load balancer via a request header (e.g. "X-Forwarded-Proto").

This valve proceeds as follows:

If the incoming request.getRemoteAddr() matches the valve's list of internal proxies :

• Loop on the comma delimited list of IPs and hostnames passed by the preceding load balancer or proxy in the given request's Http header named $remoteIpHeader (default value x-forwarded-for). Values are processed in right-to-left order.
• For each ip/host of the list:
  • if it matches the internal proxies list, the ip/host is swallowed
  • if it matches the trusted proxies list, the ip/host is added to the created proxies header
  • otherwise, the ip/host is declared to be the remote ip and looping is stopped.
• If the request http header named $protocolHeader (e.g. x-forwarded-for) equals to the value of protocolHeaderHttpsValue configuration parameter (default https) then request.isSecure = true, request.scheme = https and request.serverPort = 443. Note that 443 can be overwritten with the $httpsServerPort configuration parameter.

Configuration parameters:

This Valve may be attached to any Container, depending on the granularity of the filtering you wish to perform.

Regular expression vs. IP address blocks: mod_remoteip allows to use address blocks (e.g. 192.168/16) to configure RemoteIPInternalProxy and RemoteIPTrustedProxy ; as Tomcat doesn't have a library similar to apr_ipsubnet_test, RemoteIpValve uses regular expression to configure internalProxies and trustedProxies in the same fashion as RequestFilterValve does.

Sample with internal proxies

RemoteIpValve configuration:

 <Valve 
   className="org.apache.catalina.valves.RemoteIpValve"
   internalProxies="192\.168\.0\.10, 192\.168\.0\.11"
   remoteIpHeader="x-forwarded-for"
   remoteIpProxiesHeader="x-forwarded-by"
   protocolHeader="x-forwarded-proto"
   />

Request values:

Sample with trusted proxies

RemoteIpValve configuration:

 <Valve 
   className="org.apache.catalina.valves.RemoteIpValve"
   internalProxies="192\.168\.0\.10, 192\.168\.0\.11"
   remoteIpHeader="x-forwarded-for"
   remoteIpProxiesHeader="x-forwarded-by"
   trustedProxies="proxy1, proxy2"
   />

Request values:

Sample with internal and trusted proxies

RemoteIpValve configuration:

 <Valve 
   className="org.apache.catalina.valves.RemoteIpValve"
   internalProxies="192\.168\.0\.10, 192\.168\.0\.11"
   remoteIpHeader="x-forwarded-for"
   remoteIpProxiesHeader="x-forwarded-by"
   trustedProxies="proxy1, proxy2"
   />

Request values:

Sample with an untrusted proxy

RemoteIpValve configuration:

 <Valve 
   className="org.apache.catalina.valves.RemoteIpValve"
   internalProxies="192\.168\.0\.10, 192\.168\.0\.11"
   remoteIpHeader="x-forwarded-for"
   remoteIpProxiesHeader="x-forwarded-by"
   trustedProxies="proxy1, proxy2"
   />

Request values:

sm

protected static StringManager sm

The StringManager for this package.

RemoteIpValve

public RemoteIpValve()

commaDelimitedListToPatternArray

protected static java.util.regex.Pattern[] commaDelimitedListToPatternArray(java.lang.String commaDelimitedPatterns)

Convert a given comma delimited list of regular expressions into an array of compiled Pattern

Returns:

array of patterns (not null)

commaDelimitedListToStringArray

protected static java.lang.String[] commaDelimitedListToStringArray(java.lang.String commaDelimitedStrings)

Convert a given comma delimited list of regular expressions into an array of String

Returns:

array of patterns (non null)

listToCommaDelimitedString

protected static java.lang.String listToCommaDelimitedString(java.util.List<java.lang.String> stringList)

Convert an array of strings in a comma delimited string

matchesOne

protected static boolean matchesOne(java.lang.String str,
                                    java.util.regex.Pattern... patterns)

Return true if the given str matches at least one of the given patterns.

getHttpsServerPort

public int getHttpsServerPort()

getHttpServerPort

public int getHttpServerPort()

getInfo

public java.lang.String getInfo()

Return descriptive information about this Valve implementation.

Specified by:

getInfo in interface Valve

Overrides:

getInfo in class ValveBase

getInternalProxies

public java.lang.String getInternalProxies()

Returns:

comma delimited list of internal proxies

See Also:

setInternalProxies(String)

getProtocolHeader

public java.lang.String getProtocolHeader()

Returns:

the protocol header (e.g. "X-Forwarded-Proto")

See Also:

setProtocolHeader(String)

getProtocolHeaderHttpsValue

public java.lang.String getProtocolHeaderHttpsValue()

Returns:

the value of the protocol header for incoming https request (e.g. "https")

See Also:

setProtocolHeaderHttpsValue(String)

getProxiesHeader

public java.lang.String getProxiesHeader()

Returns:

the proxies header name (e.g. "X-Forwarded-By")

See Also:

setProxiesHeader(String)

getRemoteIpHeader

public java.lang.String getRemoteIpHeader()

Returns:

the remote IP header name (e.g. "X-Forwarded-For")

See Also:

setRemoteIpHeader(String)

getTrustedProxies

public java.lang.String getTrustedProxies()

Returns:

comma delimited list of trusted proxies

See Also:

setTrustedProxies(String)

invoke

public void invoke(Request request,
                   Response response)
            throws java.io.IOException,
                   javax.servlet.ServletException

The implementation-specific logic represented by this Valve. See the Valve description for the normal design patterns for this method.

This method MUST be provided by a subclass.

Specified by:

invoke in interface Valve

Specified by:

invoke in class ValveBase

Parameters:

request - The servlet request to be processed

response - The servlet response to be created

Throws:

java.io.IOException - if an input/output error occurs

javax.servlet.ServletException - if a servlet error occurs

setHttpServerPort

public void setHttpServerPort(int httpServerPort)

Server Port value if the protocolHeader is not null and does not indicate HTTP

Default value : 80

setHttpsServerPort

public void setHttpsServerPort(int httpsServerPort)

Server Port value if the protocolHeader indicates HTTPS

Default value : 443

setInternalProxies

public void setInternalProxies(java.lang.String commaDelimitedInternalProxies)

Comma delimited list of internal proxies. Can be expressed with regular expressions.

Default value: 10\.\d{1,3}\.\d{1,3}\.\d{1,3}, 192\.168\.\d{1,3}\.\d{1,3}, 127\.\d{1,3}\.\d{1,3}\.\d{1,3}
Note: If you want to configure the same value, you have to replace "\d{1,3}" with "\d\d?\d?" or more simply with "\d+". Otherwise the commas in the expression will be mistaken for separators between regular expressions.

setProtocolHeader

public void setProtocolHeader(java.lang.String protocolHeader)

Header that holds the incoming protocol, usally named X-Forwarded-Proto. If null, request.scheme and request.secure will not be modified.

Default value : null

setProtocolHeaderHttpsValue

public void setProtocolHeaderHttpsValue(java.lang.String protocolHeaderHttpsValue)

Case insensitive value of the protocol header to indicate that the incoming http request uses SSL.

Default value : https

setProxiesHeader

public void setProxiesHeader(java.lang.String proxiesHeader)

The proxiesHeader directive specifies a header into which mod_remoteip will collect a list of all of the intermediate client IP addresses trusted to resolve the actual remote IP. Note that intermediate RemoteIPTrustedProxy addresses are recorded in this header, while any intermediate RemoteIPInternalProxy addresses are discarded.

Name of the http header that holds the list of trusted proxies that has been traversed by the http request.

The value of this header can be comma delimited.

Default value : X-Forwarded-By

setRemoteIpHeader

public void setRemoteIpHeader(java.lang.String remoteIpHeader)

Name of the http header from which the remote ip is extracted.

The value of this header can be comma delimited.

Default value : X-Forwarded-For

Parameters:

remoteIpHeader -

setTrustedProxies

public void setTrustedProxies(java.lang.String commaDelimitedTrustedProxies)

Comma delimited list of proxies that are trusted when they appear in the remoteIpHeader header. Can be expressed as a regular expression.

Default value : empty list, no external proxy is trusted.