diff options
Diffstat (limited to 'rubbos/app/tomcat-connectors-1.2.32-src/xdocs/ajp/ajpv13ext.xml')
| -rw-r--r-- | rubbos/app/tomcat-connectors-1.2.32-src/xdocs/ajp/ajpv13ext.xml | 686 |
1 files changed, 686 insertions, 0 deletions
diff --git a/rubbos/app/tomcat-connectors-1.2.32-src/xdocs/ajp/ajpv13ext.xml b/rubbos/app/tomcat-connectors-1.2.32-src/xdocs/ajp/ajpv13ext.xml new file mode 100644 index 00000000..d3c8c3a0 --- /dev/null +++ b/rubbos/app/tomcat-connectors-1.2.32-src/xdocs/ajp/ajpv13ext.xml @@ -0,0 +1,686 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!DOCTYPE document [ + <!ENTITY project SYSTEM "project.xml"> +]> +<document url="ajpv13ext.html"> + + &project; +<copyright> + Licensed to the Apache Software Foundation (ASF) under one or more + contributor license agreements. See the NOTICE file distributed with + this work for additional information regarding copyright ownership. + The ASF licenses this file to You under the Apache License, Version 2.0 + (the "License"); you may not use this file except in compliance with + the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +</copyright> +<properties> +<title>AJPv13 extensions Proposal</title> +<author email="hgomez@apache.org">Henri Gomez</author> +<date>$Date: 2006-12-03 13:55:56 +0100 (Sun, 03 Dec 2006) $</date> +</properties> +<body> +<section name="Introduction"> +<p> +This document is a proposal of evolution of the current +Apache JServ Protocol version 1.3, also known as ajp13. +I'll not cover here the full protocol but only the add-on from ajp13. + +This nth pass include comments from the tomcat-dev list and +misses discovered during developpment. +</p> +<subsection name="Missing features in AJP13"> +<p> +ajp13 is a good protocol to link a servlet engine like tomcat to a web server like Apache: + +<ul> +<li> +use persistants connections to avoid reconnect time at each request +</li> +<li> +encode many http commands to reduce stream size +</li> +<li> +send to servlet engine many info from web server (like SSL certs) +</li> +</ul> +<p> +But ajp13 lacks support for : +</p> +<ul> +<li> + security between web server and servlet engine. + Anybody can connect to an ajp13 port (no login mecanism used) + You could connect, for example with telnet, and keep the remote thread + up by not sending any data (no timeout in connection) +</li> +<li> + context information passed from servlet engine to web server. + Part of the configuration of JK, the web server connector, is to + indicate to the web server which URI to handle. + The mod_jk JkMount directive, told to web server which URI must be + forwarded to servlet engine. + A servlet engine allready knows which URI it handle and TC 3.3 is + allready capable to generate a config file for JK from the list + of available contexts. +</li> +<li> + state update of contexts from servlet engine to web server. + Big site with farm of Tomcat, like ISP and virtuals hosters, + may need to stop a context for admin purposes. In that case the front + web server must know that the context is currently down, to eventually + relay the request to another Tomcat +</li> +<li> + verify state of connection before sending request. + Actually JK send the request to the servlet engine and next wait + for the answer. But one of the beauty of the socket API, is you that + you could write() to a closed connection without any error reporting, + but a read() to a closed connection return you the error code. +</li> +</ul> + +</p> +</subsection> + +<subsection name="Proposed add-ons to AJP13"> +<p> +Let's descrive here the features and add-on that could be added to AJP13. +Since this document is a proposal, a reasonable level of chaos must be expected at first. +Be sure that discussion on tomcat list will help clarify points, add +features but the current list seems to be a 'minimun vital' + +<ul> + +<li> +Advanced login features at connect time +</li> + +<li> +Basic authorisation system, where a shared secret key is +present in web server and servlet engine. +</li> + +<li> +Basic protocol negociation, just to be sure that if functionnalities are added +to AJP13 in the future, current implementations will still works. +</li> + +<li> +Clean handling of 'Unknown packets' +</li> + +<li> +Extended env vars passed from web-server to servlet engine. +</li> + +<li> +Add extra SSL informations needed by Servlet 2.3 API (like SSL_KEY_SIZE) +</li> + +</ul> + +</p> +</subsection> + +<subsection name="Advanced login"> +<p> + +<ol> +<li> +WEB-SERVER send LOGIN INIT CMD + NEGOCIATION DATA + WEB SERVER INFO +</li> +<li> + TOMCAT respond with LOGIN SEED CMD + RANDOM DATA +</li> +<li> + WEB-SERVER calculted the MD5 of RANDOM DATA+SECRET DATA +</li> +<li> + WEB-SERVER send LOGIN COMP CMD + MD5 (SECRET DATA + RANDOM DATA) +</li> +<li> + TOMCAT respond with LOGIN STATUS CMD + NEGOCIED DATA + SERVLET ENGINE INFO +</li> +</ol> + +To prevent DOS attack, the servlet engine will wait +the LOGIN CMD only 15/30 seconds and reports the +timeout exception for admins investigation. + +The login command will contains basic protocol +negociation information like compressing ability, +crypto, context info (at start up), context update at +run-time (up/down), level of SSL env vars, AJP protocol +level supported (level1/level2/level3...) + +The Web server info will contain web server info and +connector name (ie Apache 1.3.26 + mod_ssl 2.8.8 + mod_jk 1.2.1 + mod_perl 1.25). + +The servlet engine will mask the negociation mask with it's own +mask (what it can do) and return it when loggin is accepted. + +This will help having a basic AJP13 implementation (level 1) +on a web-server working with a more advanced protocol handler on +the servlet engine side or vice-versa. + +AJP13 was designed to be small and fast and so many +SSL informations present in the web-server are not +forwarded to the servlet engine. + +We add here four negociations flags to provide more +informations on client SSL data (certs), server SSL datas, +crypto used, and misc datas (timeout...). +</p> +</subsection> + +<subsection name="Messages Stream"> +<p> +<source> ++----------------+------------------+-----------------+ +| LOGIN INIT CMD | NEGOCIATION DATA | WEB SERVER INFO | ++----------------+------------------+-----------------+ + ++----------------+----------------+ +| LOGIN SEED CMD | MD5 of entropy | ++----------------+----------------+ + ++----------------+----------------------------+ +| LOGIN COMP CMD | MD5 of RANDOM + SECRET KEY | ++----------------+----------------------------+ + ++-----------+---------------+---------------------+ +| LOGOK CMD | NEGOCIED DATA | SERVLET ENGINE INFO | ++-----------+---------------+---------------------+ + ++------------+--------------+ +| LOGNOK CMD | FAILURE CODE | ++------------+--------------+ +</source> + +<ul> +<li> +LOGIN INIT CMD, LOGIN SEED CMD, LOGIN COMP CMD, LOGOK CMD, LOGNOK CMD are 1 byte long. +</li> +<li> +MD5, MD5 of RANDOM + SECRET KEY are 32 chars long. +</li> +<li> +NEGOCIATION DATA, NEGOCIED DATA, FAILURE CODE are 32 bits long. +</li> +<li> +WEB SERVER INFO, SERVLET ENGINE INFO are CString. +</li> +</ul> + +The secret key will be set by a new propertie in +workers.properties : secretkey +<source> +worker.ajp13.port=8009 +worker.ajp13.host=localhost +worker.ajp13.type=ajp13 +worker.ajp13.secretkey=myverysecretkey +</source> +</p> +</subsection> + +<subsection name="Shutdown feature"> +<p> +AJP13 miss a functionnality of AJP12, which is shutdown command. +A logout will tell servlet engine to shutdown itself. +<source> ++--------------+----------------------------+ +| SHUTDOWN CMD | MD5 of RANDOM + SECRET KEY | ++--------------+----------------------------+ + ++------------+ +| SHUTOK CMD | ++------------+ + ++-------------+--------------+ +| SHUTNOK CMD | FAILURE CODE | ++-------------+--------------+ +</source> + +<ul> +<li> +SHUTDOWN CMD, SHUTOK CMD, SHUTNOK CMD are 1 byte long. +</li> +<li> +MD5 of RANDOM + SECRET KEY are 32 chars long. +</li> +<li> +FAILURE CODE is 32 bits long. +</li> +</ul> + +</p> +</subsection> + +<subsection name="Extended Env Vars feature"> +<p> +NOTA: + +While working on AJP13 in JK, I really discovered "JkEnvVar". +The following "Extended Env Vars feature" description may not +be implemented in extended AJP13 since allready available in original +implementation. + +DESC: + +Many users will want to see some of their web-server env vars +passed to their servlet engine. + +To reduce the network traffic, the web-servlet will send a +table to describing the external vars in a shorter fashion. + +We'll use there a functionnality allready present in AJP13, +attributes list : + +In the AJP13, we've got : + +<source> +AJP13_FORWARD_REQUEST := + prefix_code 2 + method (byte) + protocol (string) + req_uri (string) + remote_addr (string) + remote_host (string) + server_name (string) + server_port (integer) + is_ssl (boolean) + num_headers (integer) + request_headers *(req_header_name req_header_value) + + ?context (byte string) + ?servlet_path (byte string) + ?remote_user (byte string) + ?auth_type (byte string) + ?query_string (byte string) + ?route (byte string) + ?ssl_cert (byte string) + ?ssl_cipher (byte string) + ?ssl_session (byte string) + + ?attributes *(attribute_name attribute_value) + request_terminator (byte) +</source> + +Using short 'web server attribute name' will reduce the +network traffic. + +<source> ++-------------------+---------------------------+-------------------------------+----+ +| EXTENDED VARS CMD | WEB SERVER ATTRIBUTE NAME | SERVLET ENGINE ATTRIBUTE NAME | ES | ++-------------------+---------------------------+-------------------------------+----+ +</source> + +ie : + +<source> +JkExtVars S1 SSL_CLIENT_V_START javax.servlet.request.ssl_start_cert_date +JkExtVars S2 SSL_CLIENT_V_END javax.servlet.request.ssl_end_cert_date +JkExtVars S3 SSL_SESSION_ID javax.servlet.request.ssl_session_id + + ++-------------------+----+-------------------------------------------+ +| EXTENDED VARS CMD | S1 | javax.servlet.request.ssl_start_cert_date | ++-------------------+----+-------------------------------------------+ ++----+-----------------------------------------+ +| S2 | javax.servlet.request.ssl_end_cert_date | ++----+-----------------------------------------+ ++----+-----------------------------------------+ +| S3 | javax.servlet.request.ssl_end_cert_date | ++----+-----------------------------------------+ +</source> + +During transmission in extended AJP13 we'll see attributes name +containing S1, S2, S3 and attributes values of +2001/01/03, 2002/01/03, 0123AFE56. + +This example showed the use of extended SSL vars but +any 'personnal' web-server vars like custom authentification +vars could be reused in the servlet engine. +The cost will be only some more bytes in the AJP traffic. + +<ul> +<li> +EXTENDED VARS CMD is 1 byte long. +</li> +<li> +WEB SERVER ATTRIBUTE NAME, SERVLET ENGINE ATTRIBUTE NAME are CString. +</li> +<li> +ES is an empty CString. +</li> +</ul> + +</p> +</subsection> + +<subsection name="Context informations forwarding for Servlet engine to Web Server"> +<p> +Just after the LOGON PHASE, the web server will ask for the list of contexts +and URLs/URIs handled by the servlet engine. +It will ease installation in many sites, reduce questions about configuration +on tomcat-user list, and be ready for servlet API 2.3. + +This mode will be activated by a new directive JkAutoMount + +ie: JkAutoMount examples myworker1 /examples/ + +If we want to get ALL the contexts handled by the servlet engine, willcard +could be used : + +ie: JkAutoMount * myworker1 * + +A servlet engine could have many contexts, /examples, /admin, /test. +We may want to use only some contexts for a given worker. It was +done previously, in apache HTTP server for example, by setting by +hand the JkMount accordingly in each [virtual] area of Apache. + +If you web-server support virtual hosting, we'll forward also that +information to servlet engine which will only return contexts for +that virtual host. +In that case the servlet engine will only return the URL/URI matching +these particular virtual server (defined in server.xml). +This feature will help ISP and big sites which mutualize large farm +of Tomcat in load-balancing configuration. + +<source> ++-----------------+-------------------+----------+----------+----+ +| CONTEXT QRY CMD | VIRTUAL HOST NAME | CONTEXTA | CONTEXTB | ES | ++-----------------+-------------------+----------+----------+----+ + ++------------------+-------------------+----------+-------------------+----------+---------------+----+ +| CONTEXT INFO CMD | VIRTUAL HOST NAME | CONTEXTA | URL1 URL2 URL3 ES | CONTEXTB | URL1 URL2 ... | ES | ++------------------+-------------------+----------+-------------------+----------+---------------+----+ +</source> + +We'll discover via context-query, the list of URL/MIMES handled by the remove servlet engine +for a list of contextes. +In wildcard mode, CONTEXTA will contains just '*'. + +<ul> +<li> +CONTEXT QRY CMD and CONTEXT INFO CMD are 1 byte long. +</li> +<li> +VIRTUAL HOST NAME is a CString, ie an array of chars terminated by a null byte (/0). +</li> +<li> +An empty string is just a null byte (/0). +</li> +<li> +ES is an empty CString. Indicate end of URI/URLs or end of CONTEXTs. +</li> +</ul> + +NB:<br/> +When VirtualMode is not to be used, the VIRTUAL HOST NAME is '*'. +In that case the servlet engine will send all contexts handled. +</p> +</subsection> + +<subsection name="Context informations updates from Servlet engine to Web Server"> +<p> +Context update are messages caming from the servlet engine each time a context +is desactivated/reactivated. The update will be in use when the directive JkUpdateMount. +This directive will set the AJP13_CONTEXT_UPDATE_NEG flag. + +ie: JkUpdateMount myworker1 + +<source> ++--------------------+-------------------+----------+--------+----------+--------+----+ +| CONTEXT UPDATE CMD | VIRTUAL HOST NAME | CONTEXTA | STATUS | CONTEXTB | STATUS | ES | ++--------------------+-------------------+----------+--------+----------+--------+----+ +</source> + +<ul> +<li> +CONTEXT UPDATE CMD, STATUS are 1 byte long. +</li> +<li> +VIRTUAL HOST NAME, CONTEXTS are CString. +</li> +<li> +ES is an empty CString. Indicate end of CONTEXTs. +</li> +</ul> + +NB:<br/> +When VirtualMode is not in use, the VIRTUAL HOST NAME is '*'. +STATUS is one byte indicating if context is UP/DOWN/INVALID +</p> +</subsection> + +<subsection name="Context status query to Servlet engine"> +<p> +This query will be used by the web-server to determine if a given +contexts are UP, DOWN or INVALID (and should be removed). + +<source> ++-------------------+--------------------+----------+----------+----+ +| CONTEXT STATE CMD | VIRTUAL HOST NAME | CONTEXTA | CONTEXTB | ES | ++-------------------+--------------------+----------+----------+----+ + ++-------------------------+-------------------+----------+--------+----------+--------+----+ +| CONTEXT STATE REPLY CMD | VIRTUAL HOST NAME | CONTEXTA | STATUS | CONTEXTB | STATUS | ES | ++-------------------------+-------------------+----------+-------------------+--------+----+ +</source> + +<ul> +<li> +CONTEXT STATE CMD, CONTEXT STATE REPLY CMD, STATUS are 1 byte long. +</li> +<li> +VIRTUAL HOST NAME, CONTEXTs are CString +</li> +<li> +ES is an empty CString +</li> +</ul> + +NB:<br/> +When VirtualMode is not in use, the VIRTUAL HOST NAME is an empty string. +</p> +</subsection> + +<subsection name="Handling of unknown packets"> +<p> +Sometimes even with a well negocied protocol, we may be in a situation +where one end (web server or servlet engine), will receive a message it +couldn't understand. In that case the receiver will send an +'UNKNOW PACKET CMD' with attached the unhandled message. + +<source> ++--------------------+------------------------+-------------------+ +| UNKNOWN PACKET CMD | UNHANDLED MESSAGE SIZE | UNHANDLED MESSAGE | ++--------------------+------------------------+-------------------+ +</source> + +Depending on the message, the sender will report an error and if +possible will try to forward the message to another endpoint. + +<ul> +<li> +UNKNOWN PACKET CMD is 1 byte long. +</li> +<li> +UNHANDLED MESSAGE SIZE is 16bits long. +</li> +<li> +UNHANDLED MESSAGE is an array of byte (length is contained in UNHANDLED MESSAGE SIZE) +</li> +</ul> + +NB:<br/> +added UNHANDLED MESSAGE SIZE (development) +</p> +</subsection> + +<subsection name="Verification of connection before sending request"> +<p> +NOTA: This fonctionality may never be used, since it may slow up the normal process +since requiring on the web-server side an extra IO (read) before forwarding +the request..... + +One of the beauty of socket APIs, is that you could write on a half closed socket. +When servlet engine close the socket, the web server will discover it only at the +next read() to the socket. +Basically, in the AJP13 protocol, the web server send the HTTP HEADER and HTTP BODY +(POST by chunk of 8K) to the servlet engine and then try to receive the reply. +If the connection was broken the web server will learn it only at receive time. + +We could use a buffering scheme but what happen when you use the servlet engine +for upload operations with more than 8ko of datas ? + +The hack in the AJP13 protocol is to add some bytes to read after the end of the +service : + +<source> +EXAMPLE OF DISCUSSION BETWEEN WEB SERVER AND SERVLET ENGINE + +AJP HTTP-HEADER (+ HTTP-POST) (WEB->SERVLET) + +AJP HTTP-REPLY (SERVLET->WEB) + +AJP END OF DISCUSSION (SERVLET->WEB) + +---> AJP STATUS (SERVLET->WEB AJP13) +</source> + +The AJP STATUS will not be read by the servlet engine at the end of +the request/response #N but at the begining of the next session. + +More at that time the web server could also use OS dependants functions +(or better APR functions) to determine if there is also more data +to read. And that datas could be CONTEXT Updates. + +This will avoid the web server sending a request to a +desactivated context. In that case, if the load-balancing is used, +it will search for another servlet engine to handle the request. + +And that feature will help ISP and big sites with farm of tomcat, +to updates their servlet engine without any service interruption. + +<source> ++------------+-------------+ +| STATUS CMD | STATUS DATA | ++------------+-------------+ +</source> + +<ul> +<li> +STATUS CMD and STATUS DATA are one byte long. +</li> +</ul> +</p> +</subsection> + +</section> + +<section name="Conclusion"> +<p> +The goal of the extended AJP13 protocol is to overcome some of the original AJP13 limitation. +An easier configuration, a better support for large site and farm of Tomcat, +a simple authentification system and provision for protocol updates. + +Using the stable ajp13 implementation in JK (native) and in servlet +engine (java), it's a reasonable evolution of the well known ajp13. +</p> +</section> + +<section name="Commands and IDs in extended AJP13 Index"> +<p> +Index of Commands and ID to be added in AJP13 Protocol +</p> + +<subsection name="Commands IDs"> +<p> +<table> + <tr><th>Command Name</th><th>Command Number</th></tr> + <tr><td>AJP13_LOGINIT_CMD</td><td>0x10</td></tr> + <tr><td>AJP13_LOGSEED_CMD</td><td>0x11</td></tr> + <tr><td>AJP13_LOGCOMP_CMD</td><td>0x12</td></tr> + <tr><td>AJP13_LOGOK_CMD</td><td>0x13</td></tr> + <tr><td>AJP13_LOGNOK_CMD</td><td>0x14</td></tr> + <tr><td>AJP13_CONTEXT_QRY_CMD</td><td>0x15</td></tr> + <tr><td>AJP13_CONTEXT_INFO_CMD</td><td>0x16</td></tr> + <tr><td>AJP13_CONTEXT_UPDATE_CMD</td><td>0x17</td></tr> + <tr><td>AJP13_STATUS_CMD</td><td>0x18</td></tr> + <tr><td>AJP13_SHUTDOWN_CMD</td><td>0x19</td></tr> + <tr><td>AJP13_SHUTOK_CMD</td><td>0x1A</td></tr> + <tr><td>AJP13_SHUTNOK_CMD</td><td>0x1B</td></tr> + <tr><td>AJP13_CONTEXT_STATE_CMD</td><td>0x1C</td></tr> + <tr><td>AJP13_CONTEXT_STATE_REP_CMD</td><td>0x1D</td></tr> + <tr><td>AJP13_UNKNOW_PACKET_CMD</td><td>0x1E</td></tr> +</table> + +</p> +</subsection> + +<subsection name="Negociations Flags"> +<p> +<table> + <tr><th>Command Name</th><th>Number</th><th>Description</th></tr> + <tr><td>AJP13_CONTEXT_INFO_NEG</td><td>0x80000000</td><td>web-server want context info after login</td></tr> + <tr><td>AJP13_CONTEXT_UPDATE_NEG</td><td>0x40000000</td><td>web-server want context updates</td></tr> + <tr><td>AJP13_GZIP_STREAM_NEG</td><td>0x20000000</td><td>web-server want compressed stream</td></tr> + <tr><td>AJP13_DES56_STREAM_NEG</td><td>0x10000000</td><td>web-server want crypted DES56 stream with secret key</td></tr> + <tr><td>AJP13_SSL_VSERVER_NEG</td><td>0x08000000</td><td>Extended info on server SSL vars</td></tr> + <tr><td>AJP13_SSL_VCLIENT_NEG</td><td>0x04000000</td><td>Extended info on client SSL vars</td></tr> + <tr><td>AJP13_SSL_VCRYPTO_NEG</td><td>0x02000000</td><td>Extended info on crypto SSL vars</td></tr> + <tr><td>AJP13_SSL_VMISC_NEG</td><td>0x01000000</td><td>Extended info on misc SSL vars</td></tr> +</table> + +<br/> + +<table> + <tr><th>Negociation ID</th><th>Number</th><th>Description</th></tr> + <tr><td>AJP13_PROTO_SUPPORT_AJPXX_NEG</td><td>0x00FF0000</td><td>mask of protocol supported</td></tr> + <tr><td>AJP13_PROTO_SUPPORT_AJP13L1_NEG</td><td>0x00010000</td><td>communication could use AJP13 Level 1</td></tr> + <tr><td>AJP13_PROTO_SUPPORT_AJP13L2_NEG</td><td>0x00020000</td><td>communication could use AJP13 Level 2</td></tr> + <tr><td>AJP13_PROTO_SUPPORT_AJP13L3_NEG</td><td>0x00040000</td><td>communication could use AJP13 Level 3</td></tr> +</table> + +<br/> +All others flags must be set to 0 since they are reserved for future use. + +</p> +</subsection> + +<subsection name="Failure IDs"> +<p> +<table> + <tr><th>Failure Id</th><th>Number</th></tr> + <tr><td>AJP13_BAD_KEY_ERR</td><td>0xFFFFFFFF</td></tr> + <tr><td>AJP13_ENGINE_DOWN_ERR</td><td>0xFFFFFFFE</td></tr> + <tr><td>AJP13_RETRY_LATER_ERR</td><td>0xFFFFFFFD</td></tr> + <tr><td>AJP13_SHUT_AUTHOR_FAILED_ERR</td><td>0xFFFFFFFC</td></tr> +</table> +</p> +</subsection> + +<subsection name="Status"> +<p> +<table> + <tr><th>Failure Id</th><th>Number</th></tr> + <tr><td>AJP13_CONTEXT_DOWN</td><td>0x01</td></tr> + <tr><td>AJP13_CONTEXT_UP</td><td>0x02</td></tr> + <tr><td>AJP13_CONTEXT_OK</td><td>0x03</td></tr> +</table> +</p> +</subsection> + +</section> +</body> +</document> |