From 9401f816dd0d9d550fe98a8507224bde51c4b847 Mon Sep 17 00:00:00 2001 From: hongbotian Date: Mon, 30 Nov 2015 02:41:33 -0500 Subject: upload tomcat JIRA: BOTTLENECK-7 Change-Id: I875d474869efd76ca203c30b60ebc0c3ee606d0e Signed-off-by: hongbotian --- .../xdocs/ajp/ajpv13a.xml | 698 +++++++++++++++++++++ 1 file changed, 698 insertions(+) create mode 100644 rubbos/app/tomcat-connectors-1.2.32-src/xdocs/ajp/ajpv13a.xml (limited to 'rubbos/app/tomcat-connectors-1.2.32-src/xdocs/ajp/ajpv13a.xml') diff --git a/rubbos/app/tomcat-connectors-1.2.32-src/xdocs/ajp/ajpv13a.xml b/rubbos/app/tomcat-connectors-1.2.32-src/xdocs/ajp/ajpv13a.xml new file mode 100644 index 00000000..3ab4502d --- /dev/null +++ b/rubbos/app/tomcat-connectors-1.2.32-src/xdocs/ajp/ajpv13a.xml @@ -0,0 +1,698 @@ + + +]> + + + &project; + + 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. + + +AJPv13 +danmil@shore.net +Jean-Frederic Clere +$Date: 2007-06-09 22:38:06 +0200 (Sat, 09 Jun 2007) $ + + +
+ +

+The original document was written by +Dan Milstein, danmil@shore.net +on December 2000. The present document is generated out of an xml file +to allow a more easy integration in the Tomcat documentation. + +

+ +

+This describes the Apache JServ Protocol version 1.3 (hereafter +ajp13). There is, apparently, no current documentation of how the +protocol works. This document is an attempt to remedy that, in order to +make life easier for maintainers of JK, and for anyone who wants to +port the protocol somewhere (into jakarta 4.x, for example). +

+ +
+ +
+ +

+I am not one of the designers of this protocol -- I believe that Gal +Shachor was the original designer. Everything in this document is derived +from the actual implementation I found in the tomcat 3.x code. I hope it +is useful, but I can't make any grand claims to perfect accuracy. I also +don't know why certain design decisions were made. Where I was able, I've +offered some possible justifications for certain choices, but those are +only my guesses. In general, the C code which Shachor wrote is very clean +and comprehensible (if almost totally undocumented). I've cleaned up the +Java code, and I think it's reasonably readable. +

+
+ +
+ +

+According to email from Gal Shachor to the jakarta-dev mailing list, +the original goals of JK (and thus ajp13) were to extend +mod_jserv and ajp12 by (I am only including the goals which +relate to communication between the web server and the servlet container): + +

    +
  • Increasing performance (speed, specifically).
    • + +
  • Adding support for SSL, so that isSecure() and + getScheme() will function correctly within the servlet + container. The client certificates and cipher suite will be + available to servlets as request attributes.
    • + +
+

+
+ +
+ +

+The ajp13 protocol is packet-oriented. A binary format was +presumably chosen over the more readable plain text for reasons of +performance. The web server communicates with the servlet container over +TCP connections. To cut down on the expensive process of socket creation, +the web server will attempt to maintain persistent TCP connections to the +servlet container, and to reuse a connection for multiple request/response +cycles. +

+Once a connection is assigned to a particular request, it will not be +used for any others until the request-handling cycle has terminated. In +other words, requests are not multiplexed over connections. This makes +for much simpler code at either end of the connection, although it does +cause more connections to be open at once. +

+Once the web server has opened a connection to the servlet container, +the connection can be in one of the following states: +

+

    +
  • Idle
    No request is being handled over this connection.
    • +
  • Assigned
    The connecton is handling a specific request.
    • +
+ +

+Once a connection is assigned to handle a particular request, the basic +request informaton (e.g. HTTP headers, etc) is sent over the connection in +a highly condensed form (e.g. common strings are encoded as integers). +Details of that format are below in Request Packet Structure. If there is a +body to the request (content-length > 0), that is sent in a separate +packet immediately after. +

+At this point, the servlet container is presumably ready to start +processing the request. As it does so, it can send the +following messages back to the web server: + +

    +
  • SEND_HEADERS
    Send a set of headers back to the browser.
    • + +
  • SEND_BODY_CHUNK
    Send a chunk of body data back to the browser.
    • + +
  • GET_BODY_CHUNK
    Get further data from the request if it hasn't all + been transferred yet. This is necessary because the packets have a fixed + maximum size and arbitrary amounts of data can be included the body of a + request (for uploaded files, for example). (Note: this is unrelated to + HTTP chunked tranfer).
    • + +
  • END_RESPONSE
    Finish the request-handling cycle.
    • +
+

+ +Each message is accompanied by a differently formatted packet of data. See +Response Packet Structures below for details. +

+
+ +
+ +

+There is a bit of an XDR heritage to this protocol, but it differs in +lots of ways (no 4 byte alignment, for example). +

+Byte order: I am not clear about the endian-ness of the individual +bytes. I'm guessing the bytes are little-endian, because that's what XDR +specifies, and I'm guessing that sys/socket library is magically making +that so (on the C side). If anyone with a better knowledge of socket calls +can step in, that would be great. +

+There are four data types in the protocol: bytes, booleans, integers and +strings. + +

+
Byte
+
A single byte.
+ +
Boolean
+
A single byte, 1 = true, 0 = false. Using other non-zero values as + true (i.e. C-style) may work in some places, but it won't in + others.
+ +
Integer
+
A number in the range of 0 to 2^16 (32768). Stored in 2 bytes with + the high-order byte first.
+ +
String
+
A variable-sized string (length bounded by 2^16). Encoded with the + length packed into two bytes first, followed by the string (including the + terminating '\0'). Note that the encoded length does not include + the trailing '\0' -- it is like strlen. This is a touch + confusing on the Java side, which is littered with odd autoincrement + statements to skip over these terminators. I believe the reason this was + done was to allow the C code to be extra efficient when reading strings + which the servlet container is sending back -- with the terminating \0 + character, the C code can pass around references into a single buffer, + without copying. If the \0 was missing, the C code would have to copy + things out in order to get its notion of a string. Note a size of -1 + (65535) indicates a null string and no data follow the length in this + case.
+
+

+ + +

+According to much of the code, the max packet +size is 8 * 1024 bytes (8K). The actual length of the packet is encoded in the +header. +

+ + + +

+Packets sent from the server to the container begin with +0x1234. Packets sent from the container to the server begin +with AB (that's the ASCII code for A followed by the ASCII +code for B). After those first two bytes, there is an integer (encoded as +above) with the length of the payload. Although this might suggest that +the maximum payload could be as large as 2^16, in fact, the code sets the +maximum to be 8K. + + + + + + + + + + + + + + + + + + + + + + + +
Packet Format (Server->Container)
Byte01234...(n+3)
Contents0x120x34Data Length (n)Data
+ + + + + + + + + + + + + + + + + + + + + + +
Packet Format (Container->Server)
Byte01234...(n+3)
ContentsABData Length (n)Data
+

+

+ For most packets, the first byte of the +payload encodes the type of message. The exception is for request body +packets sent from the server to the container -- they are sent with a +standard packet header (0x1234 and then length of the packet), but without +any prefix code after that (this seems like a mistake to me). +

+The web server can send the following messages to the servlet container: + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
CodeType of PacketMeaning
2Forward RequestBegin the request-processing cycle with the following data
7ShutdownThe web server asks the container to shut itself down.
8PingThe web server asks the container to take control (secure login phase).
10CPingThe web server asks the container to respond quickly with a CPong.
noneDataSize (2 bytes) and corresponding body data.
+

+

+To ensure some +basic security, the container will only actually do the Shutdown if the +request comes from the same machine on which it's hosted. +

+

+The first Data packet is send immediatly after the Forward Request by the web server. +

+ +

The servlet container can send the following types of messages to the web +server: + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
CodeType of PacketMeaning
3Send Body ChunkSend a chunk of the body from the servlet container to the web + server (and presumably, onto the browser).
4Send HeadersSend the response headers from the servlet container to the web + server (and presumably, onto the browser).
5End ResponseMarks the end of the response (and thus the request-handling cycle).
6Get Body ChunkGet further data from the request if it hasn't all been transferred + yet.
9CPong ReplyThe reply to a CPing request
+

+

+Each of the above messages has a different internal structure, detailed below. +

+ +
+ +
+ +

+For messages from the server to the container of type "Forward Request": +

+ +AJP13_FORWARD_REQUEST := + prefix_code (byte) 0x02 = JK_AJP13_FORWARD_REQUEST + 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) + attributes *(attribut_name attribute_value) + request_terminator (byte) OxFF + +

+The request_headers have the following structure: +

+ +req_header_name := + sc_req_header_name | (string) [see below for how this is parsed] + +sc_req_header_name := 0xA0xx (integer) + +req_header_value := (string) + +

+ +The attributes are optional and have the following structure: +

+ +attribute_name := sc_a_name | (sc_a_req_attribute string) + +attribute_value := (string) + + +

+Not that the all-important header is "content-length', because it +determines whether or not the container looks for another packet +immediately. +

+Detailed description of the elements of Forward Request. +

+ +

+For all requests, this will be 2. +See above for details on other prefix codes. +

+ + + +

+The HTTP method, encoded as a single byte: +

+ +

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Command NameCode
OPTIONS1
GET2
HEAD3
POST4
PUT5
DELETE6
TRACE7
PROPFIND8
PROPPATCH9
MKCOL10
COPY11
MOVE12
LOCK13
UNLOCK14
ACL15
REPORT16
VERSION-CONTROL17
CHECKIN18
CHECKOUT19
UNCHECKOUT20
SEARCH21
MKWORKSPACE22
UPDATE23
LABEL24
MERGE25
BASELINE_CONTROL26
MKACTIVITY27
+

+ +

Later version of ajp13, when used with mod_jk2, will transport +additional methods, even if they are not in this list. +

+ + + + +

+ These are all fairly self-explanatory. Each of these is required, and + will be sent for every request. +

+ + + +

+ The structure of request_headers is the following: + First, the number of headers num_headers is encoded. + Then, a series of header name req_header_name / value + req_header_value pairs follows. + Common header names are encoded as integers, + to save space. If the header name is not in the list of basic headers, + it is encoded normally (as a string, with prefixed length). The list of + common headers sc_req_header_nameand their codes + is as follows (all are case-sensitive): +

+ + + + + + + + + + + + + + + + +
NameCode valueCode name
accept0xA001SC_REQ_ACCEPT
accept-charset0xA002SC_REQ_ACCEPT_CHARSET
accept-encoding0xA003SC_REQ_ACCEPT_ENCODING
accept-language0xA004SC_REQ_ACCEPT_LANGUAGE
authorization0xA005SC_REQ_AUTHORIZATION
connection0xA006SC_REQ_CONNECTION
content-type0xA007SC_REQ_CONTENT_TYPE
content-length0xA008SC_REQ_CONTENT_LENGTH
cookie0xA009SC_REQ_COOKIE
cookie20xA00ASC_REQ_COOKIE2
host0xA00BSC_REQ_HOST
pragma0xA00CSC_REQ_PRAGMA
referer0xA00DSC_REQ_REFERER
user-agent0xA00ESC_REQ_USER_AGENT
+

+ The Java code that reads this grabs the first two-byte integer and if + it sees an '0xA0' in the most significant + byte, it uses the integer in the second byte as an index into an array of + header names. If the first byte is not '0xA0', it assumes that the + two-byte integer is the length of a string, which is then read in. +

+ This works on the assumption that no header names will have length + greater than 0x9999 (==0xA000 - 1), which is perfectly reasonable, though + somewhat arbitrary. (If you, like me, started to think about the cookie + spec here, and about how long headers can get, fear not -- this limit is + on header names not header values. It seems unlikely that + unmanageably huge header names will be showing up in the HTTP spec any time + soon). +

+ Note: The content-length header is extremely + important. If it is present and non-zero, the container assumes that + the request has a body (a POST request, for example), and immediately + reads a separate packet off the input stream to get that body. +

+ + + +

+ + The attributes prefixed with a ? + (e.g. ?context) are all optional. For each, there is a + single byte code to indicate the type of attribute, and then a string to + give its value. They can be sent in any order (thogh the C code always + sends them in the order listed below). A special terminating code is + sent to signal the end of the list of optional attributes. The list of + byte codes is: +

+ + + + + + + + + + + + + + + + + +
InformationCode ValueNote
?context0x01Not currently implemented
?servlet_path0x02Not currently implemented
?remote_user0x03
?auth_type0x04
?query_string0x05
?route0x06
?ssl_cert0x07
?ssl_cipher0x08
?ssl_session0x09
?req_attribute0x0AName (the name of the attribut follows)
?ssl_key_size0x0B
?secret0x0C
?stored_method0x0D
are_done0xFFrequest_terminator
+ +

+ + The context and servlet_path are not currently + set by the C code, and most of the Java code completely ignores whatever + is sent over for those fields (and some of it will actually break if a + string is sent along after one of those codes). I don't know if this is + a bug or an unimplemented feature or just vestigial code, but it's + missing from both sides of the connection. +

+ The remote_user and auth_type presumably refer + to HTTP-level authentication, and communicate the remote user's username + and the type of authentication used to establish their identity (e.g. Basic, + Digest). I'm not clear on why the password isn't also sent, but I don't + know HTTP authentication inside and out. +

+ The query_string, ssl_cert, + ssl_cipher, and ssl_session refer to the + corresponding pieces of HTTP and HTTPS. +

+ The route, as I understand it, is used to support sticky + sessions -- associating a user's sesson with a particular Tomcat instance + in the presence of multiple, load-balancing servers. I don't know the + details. +

+ Beyond this list of basic attributes, any number of other attributes can + be sent via the req_attribute code (0x0A). A pair of strings + to represent the attribute name and value are sent immediately after each + instance of that code. Environment values are passed in via this method. +

+ Finally, after all the attributes have been sent, the attribute terminator, + 0xFF, is sent. This signals both the end of the list of attributes and + also then end of the Request Packet. +

+ + +
+ +
+ +

+For messages which the container can send back to the server. + + +AJP13_SEND_BODY_CHUNK := + prefix_code 3 + chunk_length (integer) + chunk *(byte) + + +AJP13_SEND_HEADERS := + prefix_code 4 + http_status_code (integer) + http_status_msg (string) + num_headers (integer) + response_headers *(res_header_name header_value) + +res_header_name := + sc_res_header_name | (string) [see below for how this is parsed] + +sc_res_header_name := 0xA0 (byte) + +header_value := (string) + +AJP13_END_RESPONSE := + prefix_code 5 + reuse (boolean) + + +AJP13_GET_BODY_CHUNK := + prefix_code 6 + requested_length (integer) + + +

+

+Details: +

+ + +

+ The chunk is basically binary data, and is sent directly back to the browser. +

+ + + +

+ The status code and message are the usual HTTP things (e.g. "200" and "OK"). + The response header names are encoded the same way the request header names are. + See above for details about how the the + codes are distinguished from the strings. The codes for common headers are: +

+ +

+ + + + + + + + + + + + + +
NameCode value
Content-Type0xA001
Content-Language0xA002
Content-Length0xA003
Date0xA004
Last-Modified0xA005
Location0xA006
Set-Cookie0xA007
Set-Cookie20xA008
Servlet-Engine0xA009
Status0xA00A
WWW-Authenticate0xA00B
+ +

+ +

+ After the code or the string header name, the header value is immediately + encoded. +

+ + + + +

+ Signals the end of this request-handling cycle. If the + reuse flag is true (==1), this TCP connection can now be used to + handle new incoming requests. If reuse is false (anything + other than 1 in the actual C code), the connection should be closed. +

+ + + +

+ The container asks for more data from the request (If the body was + too large to fit in the first packet sent over or when the request is + chuncked). + The server will send a body packet back with an amount of data which is + the minimum of the request_length, + the maximum send body size (8186 (8 Kbytes - 6)), and the + number of bytes actually left to send from the request body. +
+ If there is no more data in the body (i.e. the servlet container is + trying to read past the end of the body), the server will send back an + "empty" packet, which is a body packet with a payload length of 0. + (0x12,0x34,0x00,0x00) +

+ +
+ +
+ +

What happens if the request headers > max packet size? There is no +provision to send a second packet of request headers in case there are more +than 8K (I think this is correctly handled for response headers, though I'm +not certain). I don't know if there is a way to get more than 8K worth of +data into that initial set of request headers, but I'll bet there is +(combine long cookies with long ssl information and a lot of environment +variables, and you should hit 8K easily). I think the connector would just +fail before trying to send any headers in this case, but I'm not certain.

+ +

What about authentication? There doesn't seem to be any authentication +of the connection between the web server and the container. This strikes +me as potentially dangerous.

+ +
+ + + -- cgit 1.2.3-korg