2 * Routines for AJP13 dissection
3 * Copyright 2002, Christopher K. St. John <cks@distributopia.com>
7 * Ethereal - Network traffic analyzer
8 * By Gerald Combs <gerald@ethereal.com>
9 * Copyright 1998 Gerald Combs
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version 2
14 * of the License, or (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
36 #include <epan/packet.h>
37 #include <epan/emem.h>
38 #include <epan/conversation.h>
39 #include "packet-tcp.h"
43 /* IMPORTANT IMPLEMENTATION NOTES
45 * You need to be looking at: jk/doc/AJP13.html in the
46 * jakarta-tomcat-connectors repository.
48 * If you're an ethereal dissector guru, then you can skip the rest of
49 * this. I'm writing it all down because I've written 3 dissectors so
50 * far and every time I've forgotten it all and had to re-learn it
51 * from scratch. Not this time, damnit.
53 * Dissector routines get called in two phases:
55 * The first phase is an in-order traversal of every incoming
56 * frame. Since we know it's in-order, we can set up a "conversational
57 * state" that records context-sensitive stuff like "was there a
58 * content-length in the previous request". During this first pass
59 * through the data, the "tree" parameter might be null, or not. For
60 * the regular gui-based ethereal, it's null, which means we don't
61 * actually display the dissected data in the gui quite yet. For the
62 * text based interface, we might do the parsing and display both in
65 * The second phase happens when the data is actually displayed. In
66 * this pase the "tree" param is non-null, so you've got a hook to
67 * hang the parsed-out display data on. Since there might be gigabytes
68 * worth of capture data, the display code only calls the dissector
69 * for the stuff the user actually clicks on. So you have to assume
70 * the dissector is getting called on random frames, you can't depend
71 * on ordering anymore.
73 * But some parts of the AJP13 capture stream are context sensitive.
74 * That's no big deal during the first in-order pass, but the second
75 * phase requires us to display any random frame correctly. So during
76 * the first in-order phase we create a per-frame user data structure
77 * and attach it to the frame using p_add_proto_data.
79 * Since AJP13 is a TCP/IP based protocol, writing a dissector for it
80 * requires addressing several other issues:
82 * 1) TCP/IP segments can get retransmitted or be sent out of
83 * order. Users don't normally care, because the low-level kernel
84 * networking code takes care of reassembling them properly. But we're
85 * looking at raw network packets, aren't we? The stuff on the
86 * wire. Ethereal has been getting better and better at helping
87 * dissectors with this. I'm a little fuzzy on the details, but my
88 * uderstanding is that ethereal now contains a fairly substantial
89 * user-space TCP/IP stack so it can re-assemble the data. But I might
90 * be wrong. Since AJP13 is going to be used either on the loopback
91 * interface or on a LAN, it isn't likely to be a big issues anyway.
93 * 2) AJP13 packets (PDU's or protocol data unit's in
94 * networking-speak) don't necessarily line up with TCP segments. That
95 * is, one TCP segment can have more than one AJP13 PDU, or one AJP13
96 * PDU can stretch across multiple TCP segments. Assembling them is
97 * obviously possible, but a royal pain. During the "phase one"
98 * in-order pass you have to keep track of a bunch of offsets and
99 * store which PDU goes with which TCP segment. Luckly, recent
100 * (0.9.4+) versions of ethereal provide the "tcp_dissect_pdus()"
101 * function that takes care of much of the work. See the comments in
102 * packet-tcp.c, the example code in packet-dns.c, or check the
103 * ethereal-dev archives for details.
105 * 3) Ethereal isn't guaranteed to see all the data. I'm a little
106 * unclear on all the possible failure modes, but it comes down to: a)
107 * Not your fault: it's an imperfect world, we're eavesdroppers, and
108 * stuff happens. We might totally miss packets or get garbled
109 * data. Or b) Totally your fault: you turn on the capture during the
110 * middle of an AJP13 conversation and the capture starts out with
111 * half an AJP13 PDU. This code doesn't currently handle either case
112 * very well, but you can get arbitrarily clever. Like: put in tests
113 * to see if this packet has reasonable field values, and if it
114 * doesn't, walk the offset ahead until we see a matching magic number
115 * field, then re-test. But we don't do that now, and since we're
116 * using tcp_dissect_pdu's, I'm not sure how to do it.
122 * Request/response header codes. Common headers are stored as ints in
123 * an effort to improve performance. Why can't we just have one big
127 static const value_string req_header_codes[] = {
129 { 0x02, "accept-charset" },
130 { 0x03, "accept-encoding" },
131 { 0x04, "accept-language" },
132 { 0x05, "authorization" },
133 { 0x06, "connection" },
134 { 0x07, "content-type" },
135 { 0x08, "content-length" },
141 { 0x0E, "user-agent" },
146 static const value_string rsp_header_codes[] = {
147 { 0x01, "Content-Type" },
148 { 0x02, "Content-Language" },
149 { 0x03, "Content-Length" },
151 { 0x05, "Last-Modified" },
152 { 0x06, "Location" },
153 { 0x07, "Set-Cookie" },
154 { 0x08, "Set-Cookie2" },
155 { 0x09, "Servlet-Engine" },
157 { 0x0B, "WWW-Authenticate" },
162 static const value_string mtype_codes[] = {
165 { 2, "FORWARD REQUEST" },
166 { 3, "SEND BODY CHUNK" },
167 { 4, "SEND HEADERS" },
168 { 5, "END RESPONSE" },
169 { 6, "GET BODY CHUNK" },
175 static const value_string http_method_codes[] = {
192 { 17, "VERSION-CONTROL" },
195 { 20, "UNCHECKOUT" },
202 static int proto_ajp13 = -1;
203 static int hf_ajp13_magic = -1;
204 static int hf_ajp13_len = -1;
205 static int hf_ajp13_code = -1;
206 static int hf_ajp13_method = -1;
207 static int hf_ajp13_ver = -1;
208 static int hf_ajp13_uri = -1;
209 static int hf_ajp13_raddr = -1;
210 static int hf_ajp13_rhost = -1;
211 static int hf_ajp13_srv = -1;
212 static int hf_ajp13_port = -1;
213 static int hf_ajp13_sslp = -1;
214 static int hf_ajp13_nhdr = -1;
215 static int hf_ajp13_hname = -1;
216 static int hf_ajp13_hval = -1;
217 static int hf_ajp13_rlen = -1;
218 static int hf_ajp13_reusep = -1;
219 static int hf_ajp13_rstatus= -1;
220 static int hf_ajp13_rsmsg = -1;
221 static int hf_ajp13_data = -1;
222 static gint ett_ajp13 = -1;
225 typedef struct ajp13_conv_data {
227 gboolean was_get_body_chunk; /* XXX - not used */
230 typedef struct ajp13_frame_data {
231 gboolean is_request_body;
234 /* ajp13, in sort of a belt-and-suspenders move, encodes strings with
235 * both a leading length field, and a trailing null. Mostly, see
236 * AJPv13.html. The returned length _includes_ the trailing null, if
239 * XXX - is there a tvbuff routine to handle this?
242 get_nstring(tvbuff_t *tvb, gint offset, guint8* cbuf, size_t cbuflen)
247 len = tvb_get_ntohs(tvb, offset);
254 if (copylen > cbuflen - 1)
255 copylen = cbuflen - 1;
256 tvb_memcpy(tvb, cbuf, offset+2, copylen);
257 cbuf[copylen] = '\0';
265 /* dissect a response. more work to do here.
268 display_rsp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *ajp13_tree)
270 const gchar* msg_code = NULL;
279 proto_tree_add_item(ajp13_tree, hf_ajp13_magic, tvb, pos, 2, 0);
285 proto_tree_add_item(ajp13_tree, hf_ajp13_len, tvb, pos, 2, 0);
290 mcode = tvb_get_guint8(tvb, pos);
291 msg_code = val_to_str(mcode, mtype_codes, "UNKNOWN");
292 mcode_buf=ep_alloc(32);
293 g_snprintf(mcode_buf, 32, "(%d) %s", mcode, msg_code);
295 proto_tree_add_string(ajp13_tree, hf_ajp13_code, tvb, pos, 1, mcode_buf);
298 if(check_col(pinfo->cinfo, COL_INFO))
299 col_append_str(pinfo->cinfo, COL_INFO, msg_code);
303 proto_tree_add_item(ajp13_tree, hf_ajp13_reusep, tvb, pos, 1, 0);
306 } else if (mcode == 4) {
308 guint8 rsmsg_bytes[8*1024]; /* DANGER WILL ROBINSON */
313 /* HTTP RESPONSE STATUS CODE
315 rcode_num = tvb_get_ntohs(tvb, pos);
317 proto_tree_add_item(ajp13_tree, hf_ajp13_rstatus, tvb, pos, 2, 0);
319 if(check_col(pinfo->cinfo, COL_INFO))
320 col_append_fstr(pinfo->cinfo, COL_INFO, ":%d", rcode_num);
322 /* HTTP RESPONSE STATUS MESSAGE
324 rsmsg_len = get_nstring(tvb, pos, rsmsg_bytes, sizeof rsmsg_bytes);
327 proto_tree_add_item(ajp13_tree, hf_ajp13_rsmsg, tvb, pos, rsmsg_len, 0);
329 /* dangerous assumption that we can just %s out raw bytes */
330 if(check_col(pinfo->cinfo, COL_INFO))
331 col_append_fstr(pinfo->cinfo, COL_INFO, " %s", rsmsg_bytes);
335 nhdr = tvb_get_ntohs(tvb, pos);
337 proto_tree_add_item(ajp13_tree, hf_ajp13_nhdr, tvb, pos, 2, 0);
342 for(i=0; i<nhdr; i++) {
349 const gchar* hname = NULL;
352 guint8 hname_bytes[1024];
356 hcd = tvb_get_guint8(tvb, pos);
360 hid = tvb_get_guint8(tvb, pos);
363 hname = val_to_str(hid, rsp_header_codes, "UNKNOWN");
364 /* Content-Length header (encoded by 0x08) is special */
368 int hname_len = get_nstring(tvb, pos, hname_bytes, sizeof hname_bytes);
371 hname = (gchar*)hname_bytes; /* VERY EVIL */
379 hval_len = get_nstring(tvb, pos, hval, sizeof hval);
385 hname_value=ep_alloc(512);
386 g_snprintf(hname_value, 512, "%s : %s", hname, hval);
387 proto_tree_add_string(ajp13_tree, hf_ajp13_hval, tvb, orig_pos, dp, hname_value);
391 } else if (mcode == 6) {
393 proto_tree_add_item(ajp13_tree, hf_ajp13_rlen, tvb, pos, 2, 0);
397 /* MESSAGE DATA (COPOUT)
400 proto_tree_add_item(ajp13_tree, hf_ajp13_data, tvb, pos+2, -1, 0);
406 /* dissect a request body. see AJPv13.html, but the idea is that these
407 * packets, unlike all other packets, have no type field. you just
408 * sort of have to know that they're coming based on the previous
412 display_req_body(tvbuff_t *tvb, proto_tree *ajp13_tree)
414 /*printf("ajp13:display_req_body()\n");*/
418 guint8 body_bytes[128*1024]; /* DANGER WILL ROBINSON */
424 proto_tree_add_item(ajp13_tree, hf_ajp13_magic, tvb, pos, 2, 0);
429 proto_tree_add_item(ajp13_tree, hf_ajp13_len, tvb, pos, 2, 0);
434 body_len = get_nstring(tvb, pos, body_bytes, sizeof body_bytes);
435 proto_tree_add_item(ajp13_tree, hf_ajp13_data, tvb, pos+2, body_len-1, 0);
441 /* note that even if ajp13_tree is null on the first pass, we still
442 * need to dissect the packet in order to determine if there is a
443 * content-length, and thus if there is a subsequent automatic
444 * request-body transmitted in the next request packet. if there is a
445 * content-length, we record the fact in the conversation context.
446 * ref the top of this file for comments explaining the multi-pass
450 display_req_forward(tvbuff_t *tvb, packet_info *pinfo,
451 proto_tree *ajp13_tree,
471 proto_tree_add_item(ajp13_tree, hf_ajp13_magic, tvb, pos, 2, 0);
475 proto_tree_add_item(ajp13_tree, hf_ajp13_len, tvb, pos, 2, 0);
480 cod = tvb_get_guint8(tvb, 4);
482 const gchar* msg_code = NULL;
484 msg_code = val_to_str(cod, mtype_codes, "UNKNOWN");
485 mcode_buf=ep_alloc(32);
486 g_snprintf(mcode_buf, 32, "(%d) %s", cod, msg_code);
487 proto_tree_add_string(ajp13_tree, hf_ajp13_code, tvb, pos, 1, mcode_buf);
491 /* HTTP METHOD (ENCODED AS INTEGER)
494 const gchar* meth_code = NULL;
495 meth = tvb_get_guint8(tvb, pos);
496 meth_code = val_to_str(meth, http_method_codes, "UNKNOWN");
499 mcode_buf=ep_alloc(32);
500 g_snprintf(mcode_buf, 32, "(%d) %s", meth, meth_code);
501 proto_tree_add_string(ajp13_tree, hf_ajp13_method, tvb, pos, 1, mcode_buf);
503 if(check_col(pinfo->cinfo, COL_INFO))
504 col_append_str(pinfo->cinfo, COL_INFO, meth_code);
508 /* HTTP VERSION STRING
510 ver_len = get_nstring(tvb, pos, ver, sizeof ver);
511 pos+=2; /* skip over size */
513 proto_tree_add_item(ajp13_tree, hf_ajp13_ver, tvb, pos, ver_len, 0);
514 pos=pos+ver_len; /* skip over chars + trailing null */
518 uri_len = get_nstring(tvb, pos, uri, sizeof uri);
519 pos+=2; /* skip over size */
521 proto_tree_add_item(ajp13_tree, hf_ajp13_uri, tvb, pos, uri_len, 0);
522 pos=pos+uri_len; /* skip over chars + trailing null */
525 if(check_col(pinfo->cinfo, COL_INFO))
526 col_append_fstr(pinfo->cinfo, COL_INFO, " %s %s", uri, ver);
531 raddr_len = get_nstring(tvb, pos, raddr, sizeof raddr);
532 pos+=2; /* skip over size */
534 proto_tree_add_item(ajp13_tree, hf_ajp13_raddr, tvb, pos, raddr_len, 0);
535 pos=pos+raddr_len; /* skip over chars + trailing null */
539 rhost_len = get_nstring(tvb, pos, rhost, sizeof rhost);
540 pos+=2; /* skip over size */
542 proto_tree_add_item(ajp13_tree, hf_ajp13_rhost, tvb, pos, rhost_len, 0);
543 pos=pos+rhost_len; /* skip over chars + trailing null */
547 srv_len = get_nstring(tvb, pos, srv, sizeof srv);
548 pos+=2; /* skip over size */
550 proto_tree_add_item(ajp13_tree, hf_ajp13_srv, tvb, pos, srv_len, 0);
551 pos=pos+srv_len; /* skip over chars + trailing null */
556 proto_tree_add_item(ajp13_tree, hf_ajp13_port, tvb, pos, 2, 0);
562 proto_tree_add_item(ajp13_tree, hf_ajp13_sslp, tvb, pos, 1, 0);
567 nhdr = tvb_get_ntohs(tvb, pos);
570 proto_tree_add_item(ajp13_tree, hf_ajp13_nhdr, tvb, pos, 2, 0);
572 cd->content_length = 0;
576 for(i=0; i<nhdr; i++) {
581 const gchar* hname = NULL;
589 hcd = tvb_get_guint8(tvb, pos);
593 hid = tvb_get_guint8(tvb, pos);
596 hname = val_to_str(hid, req_header_codes, "UNKNOWN");
603 hname_bytes=ep_alloc(1024);
604 hname_len = get_nstring(tvb, pos, hname_bytes, 1024);
606 hname = (gchar*)hname_bytes;
615 hval_len = get_nstring(tvb, pos, hval, 8192);
620 proto_tree_add_string_format(ajp13_tree, hf_ajp13_hval,
621 tvb, orig_pos, dp, hname,
622 "%s: %s", hname, hval);
626 cd->content_length = cl;
633 /* main dissector function. ethereal calls it for segments in both
637 dissect_ajp13_tcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
641 conversation_t *conv = NULL;
642 ajp13_conv_data *cd = NULL;
643 proto_tree *ajp13_tree = NULL;
644 ajp13_frame_data* fd = NULL;
646 /* conversational state really only does us good during the first
649 conv = find_conversation(pinfo->fd->num, &pinfo->src, &pinfo->dst, pinfo->ptype,
650 pinfo->srcport, pinfo->destport, 0);
652 conv = conversation_new(pinfo->fd->num, &pinfo->src, &pinfo->dst, pinfo->ptype,
653 pinfo->srcport, pinfo->destport, 0);
655 cd = (ajp13_conv_data*)conversation_get_proto_data(conv, proto_ajp13);
657 cd = se_alloc(sizeof(ajp13_conv_data));
658 cd->content_length = 0;
659 cd->was_get_body_chunk = FALSE;
660 conversation_add_proto_data(conv, proto_ajp13, cd);
663 /* we use the per segment user data to record the conversational
664 * state for use later on when we're called out of order (see
665 * comments at top of this file)
667 fd = (ajp13_frame_data*)p_get_proto_data(pinfo->fd, proto_ajp13);
669 /*printf("ajp13:dissect_ajp13_common():no frame data, adding");*/
670 /* since there's no per-packet user data, this must be the first
671 * time we've see the packet, and it must be the first "in order"
672 * pass through the data.
674 fd = se_alloc(sizeof(ajp13_frame_data));
675 p_add_proto_data(pinfo->fd, proto_ajp13, fd);
676 fd->is_request_body = FALSE;
677 if (cd->content_length) {
678 /* this is screwy, see AJPv13.html. the idea is that if the
679 * request has a body (as determined by the content-length
680 * header), then there's always an immediate follow-up PDU with
681 * no GET_BODY_CHUNK from the container.
683 fd->is_request_body = TRUE;
687 if (check_col(pinfo->cinfo, COL_INFO))
688 col_clear(pinfo->cinfo, COL_INFO);
690 mag = tvb_get_ntohs(tvb, 0);
691 len = tvb_get_ntohs(tvb, 2);
693 if (check_col(pinfo->cinfo, COL_PROTOCOL))
694 col_set_str(pinfo->cinfo, COL_PROTOCOL, "AJP13");
695 if (check_col(pinfo->cinfo, COL_INFO)) {
696 if (mag == 0x1234 && !fd->is_request_body)
697 col_append_fstr(pinfo->cinfo, COL_INFO, "%d:REQ:", conv->index);
698 else if (mag == 0x1234 && fd->is_request_body)
699 col_append_fstr(pinfo->cinfo, COL_INFO, "%d:REQ:Body", conv->index);
700 else if (mag == 0x4142)
701 col_append_fstr(pinfo->cinfo, COL_INFO, "%d:RSP:", conv->index);
703 col_set_str(pinfo->cinfo, COL_INFO, "AJP13 Error?");
708 ti = proto_tree_add_item(tree, proto_ajp13, tvb, 0, tvb_length(tvb), FALSE);
709 ajp13_tree = proto_item_add_subtree(ti, ett_ajp13);
714 if (fd->is_request_body)
715 display_req_body(tvb, ajp13_tree);
717 display_req_forward(tvb, pinfo, ajp13_tree, cd);
719 } else if (mag == 0x4142) {
721 display_rsp(tvb, pinfo, ajp13_tree);
728 /* given the first chunk of the AJP13 pdu, extract out and return the
729 * packet length. see comments in packet-tcp.c:tcp_dissect_pdus().
732 get_ajp13_pdu_len(tvbuff_t *tvb, int offset)
736 magic = tvb_get_ntohs(tvb, offset);
737 plen = tvb_get_ntohs(tvb, offset+2);
744 /* Code to actually dissect the packets.
747 dissect_ajp13(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
749 /* Set up structures needed to add the protocol subtree and manage it
751 tcp_dissect_pdus(tvb, pinfo, tree,
752 TRUE, /* desegment or not */
753 4, /* magic + length */
754 get_ajp13_pdu_len, /* use first 4, calc data len */
755 dissect_ajp13_tcp_pdu); /* the naive dissector */
761 proto_register_ajp13(void)
763 static hf_register_info hf[] = {
765 { "Magic", "ajp13.magic", FT_BYTES, BASE_HEX, NULL, 0x0, "Magic Number",
769 { "Length", "ajp13.len", FT_UINT16, BASE_DEC, NULL, 0x0, "Data Length",
773 { "Code", "ajp13.code", FT_STRING, BASE_DEC, NULL, 0x0, "Type Code",
777 { "Method", "ajp13.method", FT_STRING, BASE_DEC, NULL, 0x0, "HTTP Method",
781 { "Version", "ajp13.ver", FT_STRING, BASE_DEC, NULL, 0x0, "HTTP Version",
785 { "URI", "ajp13.uri", FT_STRING, BASE_DEC, NULL, 0x0, "HTTP URI",
789 { "RADDR", "ajp13.raddr", FT_STRING, BASE_DEC, NULL, 0x0, "Remote Address",
793 { "RHOST", "ajp13.rhost", FT_STRING, BASE_DEC, NULL, 0x0, "Remote Host",
797 { "SRV", "ajp13.srv", FT_STRING, BASE_DEC, NULL, 0x0, "Server",
801 { "PORT", "ajp13.port", FT_UINT16, BASE_DEC, NULL, 0x0, "Port",
805 { "SSLP", "ajp13.sslp", FT_UINT8, BASE_DEC, NULL, 0x0, "Is SSL?",
809 { "NHDR", "ajp13.nhdr", FT_UINT16, BASE_DEC, NULL, 0x0, "Num Headers",
813 { "HNAME", "ajp13.hname", FT_STRING, BASE_DEC, NULL, 0x0, "Header Name",
817 { "HVAL", "ajp13.hval", FT_STRING, BASE_DEC, NULL, 0x0, "Header Value",
821 { "RLEN", "ajp13.rlen", FT_UINT16, BASE_DEC, NULL, 0x0, "Requested Length",
825 { "REUSEP", "ajp13.reusep", FT_UINT8, BASE_DEC, NULL, 0x0, "Reuse Connection?",
829 { "RSTATUS", "ajp13.rstatus", FT_UINT16, BASE_DEC, NULL, 0x0, "HTTP Status Code",
833 { "RSMSG", "ajp13.rmsg", FT_STRING, BASE_DEC, NULL, 0x0, "HTTP Status Message",
837 { "Data", "ajp13.data", FT_STRING, BASE_DEC, NULL, 0x0, "Data",
842 static gint *ett[] = {
846 /* Register the protocol name and description
848 proto_ajp13 = proto_register_protocol("Apache JServ Protocol v1.3", "AJP13", "ajp13");
850 proto_register_field_array(proto_ajp13, hf, array_length(hf));
851 proto_register_subtree_array(ett, array_length(ett));
858 proto_reg_handoff_ajp13(void)
860 dissector_handle_t ajp13_handle;
861 ajp13_handle = create_dissector_handle(dissect_ajp13, proto_ajp13);
862 dissector_add("tcp.port", 8009, ajp13_handle);