29e82084ca71771078f0d24454b5ce9b6c850af8
[openwrt-10.03/.git] / target / linux / generic-2.6 / patches-2.6.32 / 190-netfilter_rtsp.patch
1 --- /dev/null
2 +++ b/include/linux/netfilter/nf_conntrack_rtsp.h
3 @@ -0,0 +1,63 @@
4 +/*
5 + * RTSP extension for IP connection tracking.
6 + * (C) 2003 by Tom Marshall <tmarshall at real.com>
7 + * based on ip_conntrack_irc.h
8 + *
9 + *      This program is free software; you can redistribute it and/or
10 + *      modify it under the terms of the GNU General Public License
11 + *      as published by the Free Software Foundation; either version
12 + *      2 of the License, or (at your option) any later version.
13 + */
14 +#ifndef _IP_CONNTRACK_RTSP_H
15 +#define _IP_CONNTRACK_RTSP_H
16 +
17 +//#define IP_NF_RTSP_DEBUG 1
18 +#define IP_NF_RTSP_VERSION "0.6.21"
19 +
20 +#ifdef __KERNEL__
21 +/* port block types */
22 +typedef enum {
23 +    pb_single,  /* client_port=x */
24 +    pb_range,   /* client_port=x-y */
25 +    pb_discon   /* client_port=x/y (rtspbis) */
26 +} portblock_t;
27 +
28 +/* We record seq number and length of rtsp headers here, all in host order. */
29 +
30 +/*
31 + * This structure is per expected connection.  It is a member of struct
32 + * ip_conntrack_expect.  The TCP SEQ for the conntrack expect is stored
33 + * there and we are expected to only store the length of the data which
34 + * needs replaced.  If a packet contains multiple RTSP messages, we create
35 + * one expected connection per message.
36 + *
37 + * We use these variables to mark the entire header block.  This may seem
38 + * like overkill, but the nature of RTSP requires it.  A header may appear
39 + * multiple times in a message.  We must treat two Transport headers the
40 + * same as one Transport header with two entries.
41 + */
42 +struct ip_ct_rtsp_expect
43 +{
44 +    u_int32_t   len;        /* length of header block */
45 +    portblock_t pbtype;     /* Type of port block that was requested */
46 +    u_int16_t   loport;     /* Port that was requested, low or first */
47 +    u_int16_t   hiport;     /* Port that was requested, high or second */
48 +#if 0
49 +    uint        method;     /* RTSP method */
50 +    uint        cseq;       /* CSeq from request */
51 +#endif
52 +};
53 +
54 +extern unsigned int (*nf_nat_rtsp_hook)(struct sk_buff *skb,
55 +                                enum ip_conntrack_info ctinfo,
56 +                                unsigned int matchoff, unsigned int matchlen,
57 +                                struct ip_ct_rtsp_expect *prtspexp,
58 +                                struct nf_conntrack_expect *exp);
59 +
60 +extern void (*nf_nat_rtsp_hook_expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp);
61 +
62 +#define RTSP_PORT   554
63 +
64 +#endif /* __KERNEL__ */
65 +
66 +#endif /* _IP_CONNTRACK_RTSP_H */
67 --- /dev/null
68 +++ b/include/linux/netfilter_helpers.h
69 @@ -0,0 +1,133 @@
70 +/*
71 + * Helpers for netfiler modules.  This file provides implementations for basic
72 + * functions such as strncasecmp(), etc.
73 + *
74 + * gcc will warn for defined but unused functions, so we only include the
75 + * functions requested.  The following macros are used:
76 + *   NF_NEED_STRNCASECMP        nf_strncasecmp()
77 + *   NF_NEED_STRTOU16           nf_strtou16()
78 + *   NF_NEED_STRTOU32           nf_strtou32()
79 + */
80 +#ifndef _NETFILTER_HELPERS_H
81 +#define _NETFILTER_HELPERS_H
82 +
83 +/* Only include these functions for kernel code. */
84 +#ifdef __KERNEL__
85 +
86 +#include <linux/ctype.h>
87 +#define iseol(c) ( (c) == '\r' || (c) == '\n' )
88 +
89 +/*
90 + * The standard strncasecmp()
91 + */
92 +#ifdef NF_NEED_STRNCASECMP
93 +static int
94 +nf_strncasecmp(const char* s1, const char* s2, u_int32_t len)
95 +{
96 +    if (s1 == NULL || s2 == NULL)
97 +    {
98 +        if (s1 == NULL && s2 == NULL)
99 +        {
100 +            return 0;
101 +        }
102 +        return (s1 == NULL) ? -1 : 1;
103 +    }
104 +    while (len > 0 && tolower(*s1) == tolower(*s2))
105 +    {
106 +        len--;
107 +        s1++;
108 +        s2++;
109 +    }
110 +    return ( (len == 0) ? 0 : (tolower(*s1) - tolower(*s2)) );
111 +}
112 +#endif /* NF_NEED_STRNCASECMP */
113 +
114 +/*
115 + * Parse a string containing a 16-bit unsigned integer.
116 + * Returns the number of chars used, or zero if no number is found.
117 + */
118 +#ifdef NF_NEED_STRTOU16
119 +static int
120 +nf_strtou16(const char* pbuf, u_int16_t* pval)
121 +{
122 +    int n = 0;
123 +
124 +    *pval = 0;
125 +    while (isdigit(pbuf[n]))
126 +    {
127 +        *pval = (*pval * 10) + (pbuf[n] - '0');
128 +        n++;
129 +    }
130 +
131 +    return n;
132 +}
133 +#endif /* NF_NEED_STRTOU16 */
134 +
135 +/*
136 + * Parse a string containing a 32-bit unsigned integer.
137 + * Returns the number of chars used, or zero if no number is found.
138 + */
139 +#ifdef NF_NEED_STRTOU32
140 +static int
141 +nf_strtou32(const char* pbuf, u_int32_t* pval)
142 +{
143 +    int n = 0;
144 +
145 +    *pval = 0;
146 +    while (pbuf[n] >= '0' && pbuf[n] <= '9')
147 +    {
148 +        *pval = (*pval * 10) + (pbuf[n] - '0');
149 +        n++;
150 +    }
151 +
152 +    return n;
153 +}
154 +#endif /* NF_NEED_STRTOU32 */
155 +
156 +/*
157 + * Given a buffer and length, advance to the next line and mark the current
158 + * line.
159 + */
160 +#ifdef NF_NEED_NEXTLINE
161 +static int
162 +nf_nextline(char* p, uint len, uint* poff, uint* plineoff, uint* plinelen)
163 +{
164 +    uint    off = *poff;
165 +    uint    physlen = 0;
166 +
167 +    if (off >= len)
168 +    {
169 +        return 0;
170 +    }
171 +
172 +    while (p[off] != '\n')
173 +    {
174 +        if (len-off <= 1)
175 +        {
176 +            return 0;
177 +        }
178 +
179 +        physlen++;
180 +        off++;
181 +    }
182 +
183 +    /* if we saw a crlf, physlen needs adjusted */
184 +    if (physlen > 0 && p[off] == '\n' && p[off-1] == '\r')
185 +    {
186 +        physlen--;
187 +    }
188 +
189 +    /* advance past the newline */
190 +    off++;
191 +
192 +    *plineoff = *poff;
193 +    *plinelen = physlen;
194 +    *poff = off;
195 +
196 +    return 1;
197 +}
198 +#endif /* NF_NEED_NEXTLINE */
199 +
200 +#endif /* __KERNEL__ */
201 +
202 +#endif /* _NETFILTER_HELPERS_H */
203 --- /dev/null
204 +++ b/include/linux/netfilter_mime.h
205 @@ -0,0 +1,89 @@
206 +/*
207 + * MIME functions for netfilter modules.  This file provides implementations
208 + * for basic MIME parsing.  MIME headers are used in many protocols, such as
209 + * HTTP, RTSP, SIP, etc.
210 + *
211 + * gcc will warn for defined but unused functions, so we only include the
212 + * functions requested.  The following macros are used:
213 + *   NF_NEED_MIME_NEXTLINE      nf_mime_nextline()
214 + */
215 +#ifndef _NETFILTER_MIME_H
216 +#define _NETFILTER_MIME_H
217 +
218 +/* Only include these functions for kernel code. */
219 +#ifdef __KERNEL__
220 +
221 +#include <linux/ctype.h>
222 +
223 +/*
224 + * Given a buffer and length, advance to the next line and mark the current
225 + * line.  If the current line is empty, *plinelen will be set to zero.  If
226 + * not, it will be set to the actual line length (including CRLF).
227 + *
228 + * 'line' in this context means logical line (includes LWS continuations).
229 + * Returns 1 on success, 0 on failure.
230 + */
231 +#ifdef NF_NEED_MIME_NEXTLINE
232 +static int
233 +nf_mime_nextline(char* p, uint len, uint* poff, uint* plineoff, uint* plinelen)
234 +{
235 +    uint    off = *poff;
236 +    uint    physlen = 0;
237 +    int     is_first_line = 1;
238 +
239 +    if (off >= len)
240 +    {
241 +        return 0;
242 +    }
243 +
244 +    do
245 +    {
246 +        while (p[off] != '\n')
247 +        {
248 +            if (len-off <= 1)
249 +            {
250 +                return 0;
251 +            }
252 +
253 +            physlen++;
254 +            off++;
255 +        }
256 +
257 +        /* if we saw a crlf, physlen needs adjusted */
258 +        if (physlen > 0 && p[off] == '\n' && p[off-1] == '\r')
259 +        {
260 +            physlen--;
261 +        }
262 +
263 +        /* advance past the newline */
264 +        off++;
265 +
266 +        /* check for an empty line */
267 +        if (physlen == 0)
268 +        {
269 +            break;
270 +        }
271 +
272 +        /* check for colon on the first physical line */
273 +        if (is_first_line)
274 +        {
275 +            is_first_line = 0;
276 +            if (memchr(p+(*poff), ':', physlen) == NULL)
277 +            {
278 +                return 0;
279 +            }
280 +        }
281 +    }
282 +    while (p[off] == ' ' || p[off] == '\t');
283 +
284 +    *plineoff = *poff;
285 +    *plinelen = (physlen == 0) ? 0 : (off - *poff);
286 +    *poff = off;
287 +
288 +    return 1;
289 +}
290 +#endif /* NF_NEED_MIME_NEXTLINE */
291 +
292 +#endif /* __KERNEL__ */
293 +
294 +#endif /* _NETFILTER_MIME_H */
295 --- a/net/ipv4/netfilter/Makefile
296 +++ b/net/ipv4/netfilter/Makefile
297 @@ -26,6 +26,7 @@ obj-$(CONFIG_NF_NAT_AMANDA) += nf_nat_am
298  obj-$(CONFIG_NF_NAT_FTP) += nf_nat_ftp.o
299  obj-$(CONFIG_NF_NAT_H323) += nf_nat_h323.o
300  obj-$(CONFIG_NF_NAT_IRC) += nf_nat_irc.o
301 +obj-$(CONFIG_NF_NAT_RTSP) += nf_nat_rtsp.o
302  obj-$(CONFIG_NF_NAT_PPTP) += nf_nat_pptp.o
303  obj-$(CONFIG_NF_NAT_SIP) += nf_nat_sip.o
304  obj-$(CONFIG_NF_NAT_SNMP_BASIC) += nf_nat_snmp_basic.o
305 --- a/net/netfilter/Kconfig
306 +++ b/net/netfilter/Kconfig
307 @@ -267,6 +267,16 @@ config NF_CONNTRACK_TFTP
308  
309           To compile it as a module, choose M here.  If unsure, say N.
310  
311 +config NF_CONNTRACK_RTSP
312 +       tristate "RTSP protocol support"
313 +       depends on NF_CONNTRACK
314 +       help
315 +               Support the RTSP protocol.  This allows UDP transports to be setup
316 +               properly, including RTP and RDT.
317 +
318 +               If you want to compile it as a module, say 'M' here and read
319 +               Documentation/modules.txt.  If unsure, say 'Y'.
320 +
321  config NF_CT_NETLINK
322         tristate 'Connection tracking netlink interface'
323         select NETFILTER_NETLINK
324 --- a/net/netfilter/Makefile
325 +++ b/net/netfilter/Makefile
326 @@ -33,6 +33,7 @@ obj-$(CONFIG_NF_CONNTRACK_PPTP) += nf_co
327  obj-$(CONFIG_NF_CONNTRACK_SANE) += nf_conntrack_sane.o
328  obj-$(CONFIG_NF_CONNTRACK_SIP) += nf_conntrack_sip.o
329  obj-$(CONFIG_NF_CONNTRACK_TFTP) += nf_conntrack_tftp.o
330 +obj-$(CONFIG_NF_CONNTRACK_RTSP) += nf_conntrack_rtsp.o
331  
332  # transparent proxy support
333  obj-$(CONFIG_NETFILTER_TPROXY) += nf_tproxy_core.o
334 --- a/net/ipv4/netfilter/Kconfig
335 +++ b/net/ipv4/netfilter/Kconfig
336 @@ -257,6 +257,11 @@ config NF_NAT_IRC
337         depends on NF_CONNTRACK && NF_NAT
338         default NF_NAT && NF_CONNTRACK_IRC
339  
340 +config NF_NAT_RTSP
341 +       tristate
342 +       depends on IP_NF_IPTABLES && NF_CONNTRACK && NF_NAT
343 +       default NF_NAT && NF_CONNTRACK_RTSP
344 +
345  config NF_NAT_TFTP
346         tristate
347         depends on NF_CONNTRACK && NF_NAT
348 --- /dev/null
349 +++ b/net/netfilter/nf_conntrack_rtsp.c
350 @@ -0,0 +1,517 @@
351 +/*
352 + * RTSP extension for IP connection tracking
353 + * (C) 2003 by Tom Marshall <tmarshall at real.com>
354 + * based on ip_conntrack_irc.c
355 + *
356 + *      This program is free software; you can redistribute it and/or
357 + *      modify it under the terms of the GNU General Public License
358 + *      as published by the Free Software Foundation; either version
359 + *      2 of the License, or (at your option) any later version.
360 + *
361 + * Module load syntax:
362 + *   insmod nf_conntrack_rtsp.o ports=port1,port2,...port<MAX_PORTS>
363 + *                              max_outstanding=n setup_timeout=secs
364 + *
365 + * If no ports are specified, the default will be port 554.
366 + *
367 + * With max_outstanding you can define the maximum number of not yet
368 + * answered SETUP requests per RTSP session (default 8).
369 + * With setup_timeout you can specify how long the system waits for
370 + * an expected data channel (default 300 seconds).
371 + *
372 + * 2005-02-13: Harald Welte <laforge at netfilter.org>
373 + *     - port to 2.6
374 + *     - update to recent post-2.6.11 api changes
375 + * 2006-09-14: Steven Van Acker <deepstar at singularity.be>
376 + *      - removed calls to NAT code from conntrack helper: NAT no longer needed to use rtsp-conntrack
377 + * 2007-04-18: Michael Guntsche <mike at it-loops.com>
378 + *                     - Port to new NF API
379 + */
380 +
381 +#include <linux/module.h>
382 +#include <linux/netfilter.h>
383 +#include <linux/ip.h>
384 +#include <linux/inet.h>
385 +#include <net/tcp.h>
386 +
387 +#include <net/netfilter/nf_conntrack.h>
388 +#include <net/netfilter/nf_conntrack_expect.h>
389 +#include <net/netfilter/nf_conntrack_helper.h>
390 +#include <linux/netfilter/nf_conntrack_rtsp.h>
391 +
392 +#define NF_NEED_STRNCASECMP
393 +#define NF_NEED_STRTOU16
394 +#define NF_NEED_STRTOU32
395 +#define NF_NEED_NEXTLINE
396 +#include <linux/netfilter_helpers.h>
397 +#define NF_NEED_MIME_NEXTLINE
398 +#include <linux/netfilter_mime.h>
399 +
400 +#include <linux/ctype.h>
401 +#define MAX_SIMUL_SETUP 8 /* XXX: use max_outstanding */
402 +#define INFOP(fmt, args...) printk(KERN_INFO "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args)
403 +#if 0
404 +#define DEBUGP(fmt, args...) printk(KERN_DEBUG "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args)
405 +#else
406 +#define DEBUGP(fmt, args...)
407 +#endif
408 +
409 +#define MAX_PORTS 8
410 +static int ports[MAX_PORTS];
411 +static int num_ports = 0;
412 +static int max_outstanding = 8;
413 +static unsigned int setup_timeout = 300;
414 +
415 +MODULE_AUTHOR("Tom Marshall <tmarshall at real.com>");
416 +MODULE_DESCRIPTION("RTSP connection tracking module");
417 +MODULE_LICENSE("GPL");
418 +module_param_array(ports, int, &num_ports, 0400);
419 +MODULE_PARM_DESC(ports, "port numbers of RTSP servers");
420 +module_param(max_outstanding, int, 0400);
421 +MODULE_PARM_DESC(max_outstanding, "max number of outstanding SETUP requests per RTSP session");
422 +module_param(setup_timeout, int, 0400);
423 +MODULE_PARM_DESC(setup_timeout, "timeout on for unestablished data channels");
424 +
425 +static char *rtsp_buffer;
426 +static DEFINE_SPINLOCK(rtsp_buffer_lock);
427 +
428 +unsigned int (*nf_nat_rtsp_hook)(struct sk_buff *skb,
429 +                                enum ip_conntrack_info ctinfo,
430 +                                unsigned int matchoff, unsigned int matchlen,struct ip_ct_rtsp_expect* prtspexp,
431 +                                struct nf_conntrack_expect *exp);
432 +void (*nf_nat_rtsp_hook_expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp);
433 +
434 +EXPORT_SYMBOL_GPL(nf_nat_rtsp_hook);
435 +
436 +/*
437 + * Max mappings we will allow for one RTSP connection (for RTP, the number
438 + * of allocated ports is twice this value).  Note that SMIL burns a lot of
439 + * ports so keep this reasonably high.  If this is too low, you will see a
440 + * lot of "no free client map entries" messages.
441 + */
442 +#define MAX_PORT_MAPS 16
443 +
444 +/*** default port list was here in the masq code: 554, 3030, 4040 ***/
445 +
446 +#define SKIP_WSPACE(ptr,len,off) while(off < len && isspace(*(ptr+off))) { off++; }
447 +
448 +/*
449 + * Parse an RTSP packet.
450 + *
451 + * Returns zero if parsing failed.
452 + *
453 + * Parameters:
454 + *  IN      ptcp        tcp data pointer
455 + *  IN      tcplen      tcp data len
456 + *  IN/OUT  ptcpoff     points to current tcp offset
457 + *  OUT     phdrsoff    set to offset of rtsp headers
458 + *  OUT     phdrslen    set to length of rtsp headers
459 + *  OUT     pcseqoff    set to offset of CSeq header
460 + *  OUT     pcseqlen    set to length of CSeq header
461 + */
462 +static int
463 +rtsp_parse_message(char* ptcp, uint tcplen, uint* ptcpoff,
464 +                   uint* phdrsoff, uint* phdrslen,
465 +                   uint* pcseqoff, uint* pcseqlen,
466 +                   uint* transoff, uint* translen)
467 +{
468 +       uint    entitylen = 0;
469 +       uint    lineoff;
470 +       uint    linelen;
471 +
472 +       if (!nf_nextline(ptcp, tcplen, ptcpoff, &lineoff, &linelen))
473 +               return 0;
474 +
475 +       *phdrsoff = *ptcpoff;
476 +       while (nf_mime_nextline(ptcp, tcplen, ptcpoff, &lineoff, &linelen)) {
477 +               if (linelen == 0) {
478 +                       if (entitylen > 0)
479 +                               *ptcpoff += min(entitylen, tcplen - *ptcpoff);
480 +                       break;
481 +               }
482 +               if (lineoff+linelen > tcplen) {
483 +                       INFOP("!! overrun !!\n");
484 +                       break;
485 +               }
486 +
487 +               if (nf_strncasecmp(ptcp+lineoff, "CSeq:", 5) == 0) {
488 +                       *pcseqoff = lineoff;
489 +                       *pcseqlen = linelen;
490 +               }
491 +
492 +               if (nf_strncasecmp(ptcp+lineoff, "Transport:", 10) == 0) {
493 +                       *transoff = lineoff;
494 +                       *translen = linelen;
495 +               }
496 +
497 +               if (nf_strncasecmp(ptcp+lineoff, "Content-Length:", 15) == 0) {
498 +                       uint off = lineoff+15;
499 +                       SKIP_WSPACE(ptcp+lineoff, linelen, off);
500 +                       nf_strtou32(ptcp+off, &entitylen);
501 +               }
502 +       }
503 +       *phdrslen = (*ptcpoff) - (*phdrsoff);
504 +
505 +       return 1;
506 +}
507 +
508 +/*
509 + * Find lo/hi client ports (if any) in transport header
510 + * In:
511 + *   ptcp, tcplen = packet
512 + *   tranoff, tranlen = buffer to search
513 + *
514 + * Out:
515 + *   pport_lo, pport_hi = lo/hi ports (host endian)
516 + *
517 + * Returns nonzero if any client ports found
518 + *
519 + * Note: it is valid (and expected) for the client to request multiple
520 + * transports, so we need to parse the entire line.
521 + */
522 +static int
523 +rtsp_parse_transport(char* ptran, uint tranlen,
524 +                     struct ip_ct_rtsp_expect* prtspexp)
525 +{
526 +       int     rc = 0;
527 +       uint    off = 0;
528 +
529 +       if (tranlen < 10 || !iseol(ptran[tranlen-1]) ||
530 +           nf_strncasecmp(ptran, "Transport:", 10) != 0) {
531 +               INFOP("sanity check failed\n");
532 +               return 0;
533 +       }
534 +
535 +       DEBUGP("tran='%.*s'\n", (int)tranlen, ptran);
536 +       off += 10;
537 +       SKIP_WSPACE(ptran, tranlen, off);
538 +
539 +       /* Transport: tran;field;field=val,tran;field;field=val,... */
540 +       while (off < tranlen) {
541 +               const char* pparamend;
542 +               uint        nextparamoff;
543 +
544 +               pparamend = memchr(ptran+off, ',', tranlen-off);
545 +               pparamend = (pparamend == NULL) ? ptran+tranlen : pparamend+1;
546 +               nextparamoff = pparamend-ptran;
547 +
548 +               while (off < nextparamoff) {
549 +                       const char* pfieldend;
550 +                       uint        nextfieldoff;
551 +
552 +                       pfieldend = memchr(ptran+off, ';', nextparamoff-off);
553 +                       nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
554 +
555 +                       if (strncmp(ptran+off, "client_port=", 12) == 0) {
556 +                               u_int16_t   port;
557 +                               uint        numlen;
558 +
559 +                               off += 12;
560 +                               numlen = nf_strtou16(ptran+off, &port);
561 +                               off += numlen;
562 +                               if (prtspexp->loport != 0 && prtspexp->loport != port)
563 +                                       DEBUGP("multiple ports found, port %hu ignored\n", port);
564 +                               else {
565 +                                       DEBUGP("lo port found : %hu\n", port);
566 +                                       prtspexp->loport = prtspexp->hiport = port;
567 +                                       if (ptran[off] == '-') {
568 +                                               off++;
569 +                                               numlen = nf_strtou16(ptran+off, &port);
570 +                                               off += numlen;
571 +                                               prtspexp->pbtype = pb_range;
572 +                                               prtspexp->hiport = port;
573 +
574 +                                               // If we have a range, assume rtp:
575 +                                               // loport must be even, hiport must be loport+1
576 +                                               if ((prtspexp->loport & 0x0001) != 0 ||
577 +                                                   prtspexp->hiport != prtspexp->loport+1) {
578 +                                                       DEBUGP("incorrect range: %hu-%hu, correcting\n",
579 +                                                              prtspexp->loport, prtspexp->hiport);
580 +                                                       prtspexp->loport &= 0xfffe;
581 +                                                       prtspexp->hiport = prtspexp->loport+1;
582 +                                               }
583 +                                       } else if (ptran[off] == '/') {
584 +                                               off++;
585 +                                               numlen = nf_strtou16(ptran+off, &port);
586 +                                               off += numlen;
587 +                                               prtspexp->pbtype = pb_discon;
588 +                                               prtspexp->hiport = port;
589 +                                       }
590 +                                       rc = 1;
591 +                               }
592 +                       }
593 +
594 +                       /*
595 +                        * Note we don't look for the destination parameter here.
596 +                        * If we are using NAT, the NAT module will handle it.  If not,
597 +                        * and the client is sending packets elsewhere, the expectation
598 +                        * will quietly time out.
599 +                        */
600 +
601 +                       off = nextfieldoff;
602 +               }
603 +
604 +               off = nextparamoff;
605 +       }
606 +
607 +       return rc;
608 +}
609 +
610 +void expected(struct nf_conn *ct, struct nf_conntrack_expect *exp)
611 +{
612 +    if(nf_nat_rtsp_hook_expectfn) {
613 +        nf_nat_rtsp_hook_expectfn(ct,exp);
614 +    }
615 +}
616 +
617 +/*** conntrack functions ***/
618 +
619 +/* outbound packet: client->server */
620 +
621 +static inline int
622 +help_out(struct sk_buff *skb, unsigned char *rb_ptr, unsigned int datalen,
623 +                struct nf_conn *ct, enum ip_conntrack_info ctinfo)
624 +{
625 +       struct ip_ct_rtsp_expect expinfo;
626 +
627 +       int dir = CTINFO2DIR(ctinfo);   /* = IP_CT_DIR_ORIGINAL */
628 +       //struct  tcphdr* tcph = (void*)iph + iph->ihl * 4;
629 +       //uint    tcplen = pktlen - iph->ihl * 4;
630 +       char*   pdata = rb_ptr;
631 +       //uint    datalen = tcplen - tcph->doff * 4;
632 +       uint    dataoff = 0;
633 +       int ret = NF_ACCEPT;
634 +
635 +       struct nf_conntrack_expect *exp;
636 +
637 +       __be16 be_loport;
638 +
639 +       memset(&expinfo, 0, sizeof(expinfo));
640 +
641 +       while (dataoff < datalen) {
642 +               uint    cmdoff = dataoff;
643 +               uint    hdrsoff = 0;
644 +               uint    hdrslen = 0;
645 +               uint    cseqoff = 0;
646 +               uint    cseqlen = 0;
647 +               uint    transoff = 0;
648 +               uint    translen = 0;
649 +               uint    off;
650 +
651 +               if (!rtsp_parse_message(pdata, datalen, &dataoff,
652 +                                       &hdrsoff, &hdrslen,
653 +                                       &cseqoff, &cseqlen,
654 +                                       &transoff, &translen))
655 +                       break;      /* not a valid message */
656 +
657 +               if (strncmp(pdata+cmdoff, "SETUP ", 6) != 0)
658 +                       continue;   /* not a SETUP message */
659 +               DEBUGP("found a setup message\n");
660 +
661 +               off = 0;
662 +               if(translen) {
663 +                       rtsp_parse_transport(pdata+transoff, translen, &expinfo);
664 +               }
665 +
666 +               if (expinfo.loport == 0) {
667 +                       DEBUGP("no udp transports found\n");
668 +                       continue;   /* no udp transports found */
669 +               }
670 +
671 +               DEBUGP("udp transport found, ports=(%d,%hu,%hu)\n",
672 +                      (int)expinfo.pbtype, expinfo.loport, expinfo.hiport);
673 +
674 +               exp = nf_ct_expect_alloc(ct);
675 +               if (!exp) {
676 +                       ret = NF_DROP;
677 +                       goto out;
678 +               }
679 +
680 +               be_loport = htons(expinfo.loport);
681 +
682 +               nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT,
683 +                       ct->tuplehash[!dir].tuple.src.l3num,
684 +                       &ct->tuplehash[!dir].tuple.src.u3, &ct->tuplehash[!dir].tuple.dst.u3,
685 +                       IPPROTO_UDP, NULL, &be_loport);
686 +
687 +               exp->master = ct;
688 +
689 +               exp->expectfn = expected;
690 +               exp->flags = 0;
691 +
692 +               if (expinfo.pbtype == pb_range) {
693 +                       DEBUGP("Changing expectation mask to handle multiple ports\n");
694 +                       exp->mask.src.u.udp.port  = 0xfffe;
695 +               }
696 +
697 +               DEBUGP("expect_related %u.%u.%u.%u:%u-%u.%u.%u.%u:%u\n",
698 +                      NIPQUAD(exp->tuple.src.u3.ip),
699 +                      ntohs(exp->tuple.src.u.udp.port),
700 +                      NIPQUAD(exp->tuple.dst.u3.ip),
701 +                      ntohs(exp->tuple.dst.u.udp.port));
702 +
703 +               if (nf_nat_rtsp_hook)
704 +                       /* pass the request off to the nat helper */
705 +                       ret = nf_nat_rtsp_hook(skb, ctinfo, hdrsoff, hdrslen, &expinfo, exp);
706 +               else if (nf_ct_expect_related(exp) != 0) {
707 +                       INFOP("nf_ct_expect_related failed\n");
708 +                       ret  = NF_DROP;
709 +               }
710 +               nf_ct_expect_put(exp);
711 +               goto out;
712 +       }
713 +out:
714 +
715 +       return ret;
716 +}
717 +
718 +
719 +static inline int
720 +help_in(struct sk_buff *skb, size_t pktlen,
721 + struct nf_conn* ct, enum ip_conntrack_info ctinfo)
722 +{
723 + return NF_ACCEPT;
724 +}
725 +
726 +static int help(struct sk_buff *skb, unsigned int protoff,
727 +               struct nf_conn *ct, enum ip_conntrack_info ctinfo)
728 +{
729 +       struct tcphdr _tcph, *th;
730 +       unsigned int dataoff, datalen;
731 +       char *rb_ptr;
732 +       int ret = NF_DROP;
733 +
734 +       /* Until there's been traffic both ways, don't look in packets. */
735 +       if (ctinfo != IP_CT_ESTABLISHED &&
736 +           ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) {
737 +               DEBUGP("conntrackinfo = %u\n", ctinfo);
738 +               return NF_ACCEPT;
739 +       }
740 +
741 +       /* Not whole TCP header? */
742 +       th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
743 +
744 +       if (!th)
745 +               return NF_ACCEPT;
746 +
747 +       /* No data ? */
748 +       dataoff = protoff + th->doff*4;
749 +       datalen = skb->len - dataoff;
750 +       if (dataoff >= skb->len)
751 +               return NF_ACCEPT;
752 +
753 +       spin_lock_bh(&rtsp_buffer_lock);
754 +       rb_ptr = skb_header_pointer(skb, dataoff,
755 +                                   skb->len - dataoff, rtsp_buffer);
756 +       BUG_ON(rb_ptr == NULL);
757 +
758 +#if 0
759 +       /* Checksum invalid?  Ignore. */
760 +       /* FIXME: Source route IP option packets --RR */
761 +       if (tcp_v4_check(tcph, tcplen, iph->saddr, iph->daddr,
762 +                        csum_partial((char*)tcph, tcplen, 0)))
763 +       {
764 +               DEBUGP("bad csum: %p %u %u.%u.%u.%u %u.%u.%u.%u\n",
765 +                      tcph, tcplen, NIPQUAD(iph->saddr), NIPQUAD(iph->daddr));
766 +               return NF_ACCEPT;
767 +       }
768 +#endif
769 +
770 +       switch (CTINFO2DIR(ctinfo)) {
771 +       case IP_CT_DIR_ORIGINAL:
772 +               ret = help_out(skb, rb_ptr, datalen, ct, ctinfo);
773 +               break;
774 +       case IP_CT_DIR_REPLY:
775 +               DEBUGP("IP_CT_DIR_REPLY\n");
776 +               /* inbound packet: server->client */
777 +               ret = NF_ACCEPT;
778 +               break;
779 +       }
780 +
781 +       spin_unlock_bh(&rtsp_buffer_lock);
782 +
783 +       return ret;
784 +}
785 +
786 +static struct nf_conntrack_helper rtsp_helpers[MAX_PORTS];
787 +static char rtsp_names[MAX_PORTS][10];
788 +static struct nf_conntrack_expect_policy rtsp_expect_policy;
789 +
790 +/* This function is intentionally _NOT_ defined as __exit */
791 +static void
792 +fini(void)
793 +{
794 +       int i;
795 +       for (i = 0; i < num_ports; i++) {
796 +               DEBUGP("unregistering port %d\n", ports[i]);
797 +               nf_conntrack_helper_unregister(&rtsp_helpers[i]);
798 +       }
799 +       kfree(rtsp_buffer);
800 +}
801 +
802 +static int __init
803 +init(void)
804 +{
805 +       int i, ret;
806 +       struct nf_conntrack_helper *hlpr;
807 +       char *tmpname;
808 +
809 +       printk("nf_conntrack_rtsp v" IP_NF_RTSP_VERSION " loading\n");
810 +
811 +       if (max_outstanding < 1) {
812 +               printk("nf_conntrack_rtsp: max_outstanding must be a positive integer\n");
813 +               return -EBUSY;
814 +       }
815 +       if (setup_timeout < 0) {
816 +               printk("nf_conntrack_rtsp: setup_timeout must be a positive integer\n");
817 +               return -EBUSY;
818 +       }
819 +
820 +       rtsp_expect_policy.max_expected = max_outstanding;
821 +       rtsp_expect_policy.timeout = setup_timeout;
822 +
823 +       rtsp_buffer = kmalloc(65536, GFP_KERNEL);
824 +       if (!rtsp_buffer)
825 +               return -ENOMEM;
826 +
827 +       /* If no port given, default to standard rtsp port */
828 +       if (ports[0] == 0) {
829 +               ports[0] = RTSP_PORT;
830 +       }
831 +
832 +       for (i = 0; (i < MAX_PORTS) && ports[i]; i++) {
833 +               hlpr = &rtsp_helpers[i];
834 +               memset(hlpr, 0, sizeof(struct nf_conntrack_helper));
835 +               hlpr->tuple.src.u.tcp.port = htons(ports[i]);
836 +               hlpr->tuple.dst.protonum = IPPROTO_TCP;
837 +               hlpr->expect_policy = &rtsp_expect_policy;
838 +               hlpr->me = THIS_MODULE;
839 +               hlpr->help = help;
840 +
841 +               tmpname = &rtsp_names[i][0];
842 +               if (ports[i] == RTSP_PORT) {
843 +                       sprintf(tmpname, "rtsp");
844 +               } else {
845 +                       sprintf(tmpname, "rtsp-%d", i);
846 +               }
847 +               hlpr->name = tmpname;
848 +
849 +               DEBUGP("port #%d: %d\n", i, ports[i]);
850 +
851 +               ret = nf_conntrack_helper_register(hlpr);
852 +
853 +               if (ret) {
854 +                       printk("nf_conntrack_rtsp: ERROR registering port %d\n", ports[i]);
855 +                       fini();
856 +                       return -EBUSY;
857 +               }
858 +               num_ports++;
859 +       }
860 +       return 0;
861 +}
862 +
863 +module_init(init);
864 +module_exit(fini);
865 +
866 +EXPORT_SYMBOL(nf_nat_rtsp_hook_expectfn);
867 +
868 --- /dev/null
869 +++ b/net/ipv4/netfilter/nf_nat_rtsp.c
870 @@ -0,0 +1,496 @@
871 +/*
872 + * RTSP extension for TCP NAT alteration
873 + * (C) 2003 by Tom Marshall <tmarshall at real.com>
874 + * based on ip_nat_irc.c
875 + *
876 + *      This program is free software; you can redistribute it and/or
877 + *      modify it under the terms of the GNU General Public License
878 + *      as published by the Free Software Foundation; either version
879 + *      2 of the License, or (at your option) any later version.
880 + *
881 + * Module load syntax:
882 + *      insmod nf_nat_rtsp.o ports=port1,port2,...port<MAX_PORTS>
883 + *                           stunaddr=<address>
884 + *                           destaction=[auto|strip|none]
885 + *
886 + * If no ports are specified, the default will be port 554 only.
887 + *
888 + * stunaddr specifies the address used to detect that a client is using STUN.
889 + * If this address is seen in the destination parameter, it is assumed that
890 + * the client has already punched a UDP hole in the firewall, so we don't
891 + * mangle the client_port.  If none is specified, it is autodetected.  It
892 + * only needs to be set if you have multiple levels of NAT.  It should be
893 + * set to the external address that the STUN clients detect.  Note that in
894 + * this case, it will not be possible for clients to use UDP with servers
895 + * between the NATs.
896 + *
897 + * If no destaction is specified, auto is used.
898 + *   destaction=auto:  strip destination parameter if it is not stunaddr.
899 + *   destaction=strip: always strip destination parameter (not recommended).
900 + *   destaction=none:  do not touch destination parameter (not recommended).
901 + */
902 +
903 +#include <linux/module.h>
904 +#include <net/tcp.h>
905 +#include <net/netfilter/nf_nat_helper.h>
906 +#include <net/netfilter/nf_nat_rule.h>
907 +#include <linux/netfilter/nf_conntrack_rtsp.h>
908 +#include <net/netfilter/nf_conntrack_expect.h>
909 +
910 +#include <linux/inet.h>
911 +#include <linux/ctype.h>
912 +#define NF_NEED_STRNCASECMP
913 +#define NF_NEED_STRTOU16
914 +#include <linux/netfilter_helpers.h>
915 +#define NF_NEED_MIME_NEXTLINE
916 +#include <linux/netfilter_mime.h>
917 +
918 +#define INFOP(fmt, args...) printk(KERN_INFO "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args)
919 +#if 0
920 +#define DEBUGP(fmt, args...) printk(KERN_DEBUG "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args)
921 +#else
922 +#define DEBUGP(fmt, args...)
923 +#endif
924 +
925 +#define MAX_PORTS       8
926 +#define DSTACT_AUTO     0
927 +#define DSTACT_STRIP    1
928 +#define DSTACT_NONE     2
929 +
930 +static char*    stunaddr = NULL;
931 +static char*    destaction = NULL;
932 +
933 +static u_int32_t extip = 0;
934 +static int       dstact = 0;
935 +
936 +MODULE_AUTHOR("Tom Marshall <tmarshall at real.com>");
937 +MODULE_DESCRIPTION("RTSP network address translation module");
938 +MODULE_LICENSE("GPL");
939 +module_param(stunaddr, charp, 0644);
940 +MODULE_PARM_DESC(stunaddr, "Address for detecting STUN");
941 +module_param(destaction, charp, 0644);
942 +MODULE_PARM_DESC(destaction, "Action for destination parameter (auto/strip/none)");
943 +
944 +#define SKIP_WSPACE(ptr,len,off) while(off < len && isspace(*(ptr+off))) { off++; }
945 +
946 +/*** helper functions ***/
947 +
948 +static void
949 +get_skb_tcpdata(struct sk_buff* skb, char** pptcpdata, uint* ptcpdatalen)
950 +{
951 +    struct iphdr*   iph  = ip_hdr(skb);
952 +    struct tcphdr*  tcph = (void *)iph + ip_hdrlen(skb);
953 +
954 +    *pptcpdata = (char*)tcph +  tcph->doff*4;
955 +    *ptcpdatalen = ((char*)skb_transport_header(skb) + skb->len) - *pptcpdata;
956 +}
957 +
958 +/*** nat functions ***/
959 +
960 +/*
961 + * Mangle the "Transport:" header:
962 + *   - Replace all occurences of "client_port=<spec>"
963 + *   - Handle destination parameter
964 + *
965 + * In:
966 + *   ct, ctinfo = conntrack context
967 + *   skb        = packet
968 + *   tranoff    = Transport header offset from TCP data
969 + *   tranlen    = Transport header length (incl. CRLF)
970 + *   rport_lo   = replacement low  port (host endian)
971 + *   rport_hi   = replacement high port (host endian)
972 + *
973 + * Returns packet size difference.
974 + *
975 + * Assumes that a complete transport header is present, ending with CR or LF
976 + */
977 +static int
978 +rtsp_mangle_tran(enum ip_conntrack_info ctinfo,
979 +                 struct nf_conntrack_expect* exp,
980 +                                                                struct ip_ct_rtsp_expect* prtspexp,
981 +                 struct sk_buff* skb, uint tranoff, uint tranlen)
982 +{
983 +    char*       ptcp;
984 +    uint        tcplen;
985 +    char*       ptran;
986 +    char        rbuf1[16];      /* Replacement buffer (one port) */
987 +    uint        rbuf1len;       /* Replacement len (one port) */
988 +    char        rbufa[16];      /* Replacement buffer (all ports) */
989 +    uint        rbufalen;       /* Replacement len (all ports) */
990 +    u_int32_t   newip;
991 +    u_int16_t   loport, hiport;
992 +    uint        off = 0;
993 +    uint        diff;           /* Number of bytes we removed */
994 +
995 +    struct nf_conn *ct = exp->master;
996 +    struct nf_conntrack_tuple *t;
997 +
998 +    char    szextaddr[15+1];
999 +    uint    extaddrlen;
1000 +    int     is_stun;
1001 +
1002 +    get_skb_tcpdata(skb, &ptcp, &tcplen);
1003 +    ptran = ptcp+tranoff;
1004 +
1005 +    if (tranoff+tranlen > tcplen || tcplen-tranoff < tranlen ||
1006 +        tranlen < 10 || !iseol(ptran[tranlen-1]) ||
1007 +        nf_strncasecmp(ptran, "Transport:", 10) != 0)
1008 +    {
1009 +        INFOP("sanity check failed\n");
1010 +        return 0;
1011 +    }
1012 +    off += 10;
1013 +    SKIP_WSPACE(ptcp+tranoff, tranlen, off);
1014 +
1015 +    newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip;
1016 +    t = &exp->tuple;
1017 +    t->dst.u3.ip = newip;
1018 +
1019 +    extaddrlen = extip ? sprintf(szextaddr, "%u.%u.%u.%u", NIPQUAD(extip))
1020 +                       : sprintf(szextaddr, "%u.%u.%u.%u", NIPQUAD(newip));
1021 +    DEBUGP("stunaddr=%s (%s)\n", szextaddr, (extip?"forced":"auto"));
1022 +
1023 +    rbuf1len = rbufalen = 0;
1024 +    switch (prtspexp->pbtype)
1025 +    {
1026 +    case pb_single:
1027 +        for (loport = prtspexp->loport; loport != 0; loport++) /* XXX: improper wrap? */
1028 +        {
1029 +            t->dst.u.udp.port = htons(loport);
1030 +            if (nf_ct_expect_related(exp) == 0)
1031 +            {
1032 +                DEBUGP("using port %hu\n", loport);
1033 +                break;
1034 +            }
1035 +        }
1036 +        if (loport != 0)
1037 +        {
1038 +            rbuf1len = sprintf(rbuf1, "%hu", loport);
1039 +            rbufalen = sprintf(rbufa, "%hu", loport);
1040 +        }
1041 +        break;
1042 +    case pb_range:
1043 +        for (loport = prtspexp->loport; loport != 0; loport += 2) /* XXX: improper wrap? */
1044 +        {
1045 +            t->dst.u.udp.port = htons(loport);
1046 +            if (nf_ct_expect_related(exp) == 0)
1047 +            {
1048 +                hiport = loport + ~exp->mask.src.u.udp.port;
1049 +                DEBUGP("using ports %hu-%hu\n", loport, hiport);
1050 +                break;
1051 +            }
1052 +        }
1053 +        if (loport != 0)
1054 +        {
1055 +            rbuf1len = sprintf(rbuf1, "%hu", loport);
1056 +            rbufalen = sprintf(rbufa, "%hu-%hu", loport, loport+1);
1057 +        }
1058 +        break;
1059 +    case pb_discon:
1060 +        for (loport = prtspexp->loport; loport != 0; loport++) /* XXX: improper wrap? */
1061 +        {
1062 +            t->dst.u.udp.port = htons(loport);
1063 +            if (nf_ct_expect_related(exp) == 0)
1064 +            {
1065 +                DEBUGP("using port %hu (1 of 2)\n", loport);
1066 +                break;
1067 +            }
1068 +        }
1069 +        for (hiport = prtspexp->hiport; hiport != 0; hiport++) /* XXX: improper wrap? */
1070 +        {
1071 +            t->dst.u.udp.port = htons(hiport);
1072 +            if (nf_ct_expect_related(exp) == 0)
1073 +            {
1074 +                DEBUGP("using port %hu (2 of 2)\n", hiport);
1075 +                break;
1076 +            }
1077 +        }
1078 +        if (loport != 0 && hiport != 0)
1079 +        {
1080 +            rbuf1len = sprintf(rbuf1, "%hu", loport);
1081 +            if (hiport == loport+1)
1082 +            {
1083 +                rbufalen = sprintf(rbufa, "%hu-%hu", loport, hiport);
1084 +            }
1085 +            else
1086 +            {
1087 +                rbufalen = sprintf(rbufa, "%hu/%hu", loport, hiport);
1088 +            }
1089 +        }
1090 +        break;
1091 +    }
1092 +
1093 +    if (rbuf1len == 0)
1094 +    {
1095 +        return 0;   /* cannot get replacement port(s) */
1096 +    }
1097 +
1098 +    /* Transport: tran;field;field=val,tran;field;field=val,... */
1099 +    while (off < tranlen)
1100 +    {
1101 +        uint        saveoff;
1102 +        const char* pparamend;
1103 +        uint        nextparamoff;
1104 +
1105 +        pparamend = memchr(ptran+off, ',', tranlen-off);
1106 +        pparamend = (pparamend == NULL) ? ptran+tranlen : pparamend+1;
1107 +        nextparamoff = pparamend-ptcp;
1108 +
1109 +        /*
1110 +         * We pass over each param twice.  On the first pass, we look for a
1111 +         * destination= field.  It is handled by the security policy.  If it
1112 +         * is present, allowed, and equal to our external address, we assume
1113 +         * that STUN is being used and we leave the client_port= field alone.
1114 +         */
1115 +        is_stun = 0;
1116 +        saveoff = off;
1117 +        while (off < nextparamoff)
1118 +        {
1119 +            const char* pfieldend;
1120 +            uint        nextfieldoff;
1121 +
1122 +            pfieldend = memchr(ptran+off, ';', nextparamoff-off);
1123 +            nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
1124 +
1125 +            if (dstact != DSTACT_NONE && strncmp(ptran+off, "destination=", 12) == 0)
1126 +            {
1127 +                if (strncmp(ptran+off+12, szextaddr, extaddrlen) == 0)
1128 +                {
1129 +                    is_stun = 1;
1130 +                }
1131 +                if (dstact == DSTACT_STRIP || (dstact == DSTACT_AUTO && !is_stun))
1132 +                {
1133 +                    diff = nextfieldoff-off;
1134 +                    if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
1135 +                                                         off, diff, NULL, 0))
1136 +                    {
1137 +                        /* mangle failed, all we can do is bail */
1138 +                       nf_ct_unexpect_related(exp);
1139 +                        return 0;
1140 +                    }
1141 +                    get_skb_tcpdata(skb, &ptcp, &tcplen);
1142 +                    ptran = ptcp+tranoff;
1143 +                    tranlen -= diff;
1144 +                    nextparamoff -= diff;
1145 +                    nextfieldoff -= diff;
1146 +                }
1147 +            }
1148 +
1149 +            off = nextfieldoff;
1150 +        }
1151 +        if (is_stun)
1152 +        {
1153 +            continue;
1154 +        }
1155 +        off = saveoff;
1156 +        while (off < nextparamoff)
1157 +        {
1158 +            const char* pfieldend;
1159 +            uint        nextfieldoff;
1160 +
1161 +            pfieldend = memchr(ptran+off, ';', nextparamoff-off);
1162 +            nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
1163 +
1164 +            if (strncmp(ptran+off, "client_port=", 12) == 0)
1165 +            {
1166 +                u_int16_t   port;
1167 +                uint        numlen;
1168 +                uint        origoff;
1169 +                uint        origlen;
1170 +                char*       rbuf    = rbuf1;
1171 +                uint        rbuflen = rbuf1len;
1172 +
1173 +                off += 12;
1174 +                origoff = (ptran-ptcp)+off;
1175 +                origlen = 0;
1176 +                numlen = nf_strtou16(ptran+off, &port);
1177 +                off += numlen;
1178 +                origlen += numlen;
1179 +                if (port != prtspexp->loport)
1180 +                {
1181 +                    DEBUGP("multiple ports found, port %hu ignored\n", port);
1182 +                }
1183 +                else
1184 +                {
1185 +                    if (ptran[off] == '-' || ptran[off] == '/')
1186 +                    {
1187 +                        off++;
1188 +                        origlen++;
1189 +                        numlen = nf_strtou16(ptran+off, &port);
1190 +                        off += numlen;
1191 +                        origlen += numlen;
1192 +                        rbuf = rbufa;
1193 +                        rbuflen = rbufalen;
1194 +                    }
1195 +
1196 +                    /*
1197 +                     * note we cannot just memcpy() if the sizes are the same.
1198 +                     * the mangle function does skb resizing, checks for a
1199 +                     * cloned skb, and updates the checksums.
1200 +                     *
1201 +                     * parameter 4 below is offset from start of tcp data.
1202 +                     */
1203 +                    diff = origlen-rbuflen;
1204 +                    if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
1205 +                                              origoff, origlen, rbuf, rbuflen))
1206 +                    {
1207 +                        /* mangle failed, all we can do is bail */
1208 +                       nf_ct_unexpect_related(exp);
1209 +                        return 0;
1210 +                    }
1211 +                    get_skb_tcpdata(skb, &ptcp, &tcplen);
1212 +                    ptran = ptcp+tranoff;
1213 +                    tranlen -= diff;
1214 +                    nextparamoff -= diff;
1215 +                    nextfieldoff -= diff;
1216 +                }
1217 +            }
1218 +
1219 +            off = nextfieldoff;
1220 +        }
1221 +
1222 +        off = nextparamoff;
1223 +    }
1224 +
1225 +    return 1;
1226 +}
1227 +
1228 +static uint
1229 +help_out(struct sk_buff *skb, enum ip_conntrack_info ctinfo,
1230 +        unsigned int matchoff, unsigned int matchlen, struct ip_ct_rtsp_expect* prtspexp,
1231 +        struct nf_conntrack_expect* exp)
1232 +{
1233 +    char*   ptcp;
1234 +    uint    tcplen;
1235 +    uint    hdrsoff;
1236 +    uint    hdrslen;
1237 +    uint    lineoff;
1238 +    uint    linelen;
1239 +    uint    off;
1240 +
1241 +    //struct iphdr* iph = (struct iphdr*)skb->nh.iph;
1242 +    //struct tcphdr* tcph = (struct tcphdr*)((void*)iph + iph->ihl*4);
1243 +
1244 +    get_skb_tcpdata(skb, &ptcp, &tcplen);
1245 +    hdrsoff = matchoff;//exp->seq - ntohl(tcph->seq);
1246 +    hdrslen = matchlen;
1247 +    off = hdrsoff;
1248 +    DEBUGP("NAT rtsp help_out\n");
1249 +
1250 +    while (nf_mime_nextline(ptcp, hdrsoff+hdrslen, &off, &lineoff, &linelen))
1251 +    {
1252 +        if (linelen == 0)
1253 +        {
1254 +            break;
1255 +        }
1256 +        if (off > hdrsoff+hdrslen)
1257 +        {
1258 +            INFOP("!! overrun !!");
1259 +            break;
1260 +        }
1261 +        DEBUGP("hdr: len=%u, %.*s", linelen, (int)linelen, ptcp+lineoff);
1262 +
1263 +        if (nf_strncasecmp(ptcp+lineoff, "Transport:", 10) == 0)
1264 +        {
1265 +            uint oldtcplen = tcplen;
1266 +           DEBUGP("hdr: Transport\n");
1267 +            if (!rtsp_mangle_tran(ctinfo, exp, prtspexp, skb, lineoff, linelen))
1268 +            {
1269 +               DEBUGP("hdr: Transport mangle failed");
1270 +                break;
1271 +            }
1272 +            get_skb_tcpdata(skb, &ptcp, &tcplen);
1273 +            hdrslen -= (oldtcplen-tcplen);
1274 +            off -= (oldtcplen-tcplen);
1275 +            lineoff -= (oldtcplen-tcplen);
1276 +            linelen -= (oldtcplen-tcplen);
1277 +            DEBUGP("rep: len=%u, %.*s", linelen, (int)linelen, ptcp+lineoff);
1278 +        }
1279 +    }
1280 +
1281 +    return NF_ACCEPT;
1282 +}
1283 +
1284 +static unsigned int
1285 +help(struct sk_buff *skb, enum ip_conntrack_info ctinfo,
1286 +     unsigned int matchoff, unsigned int matchlen, struct ip_ct_rtsp_expect* prtspexp,
1287 +     struct nf_conntrack_expect* exp)
1288 +{
1289 +    int dir = CTINFO2DIR(ctinfo);
1290 +    int rc = NF_ACCEPT;
1291 +
1292 +    switch (dir)
1293 +    {
1294 +    case IP_CT_DIR_ORIGINAL:
1295 +        rc = help_out(skb, ctinfo, matchoff, matchlen, prtspexp, exp);
1296 +        break;
1297 +    case IP_CT_DIR_REPLY:
1298 +       DEBUGP("unmangle ! %u\n", ctinfo);
1299 +       /* XXX: unmangle */
1300 +       rc = NF_ACCEPT;
1301 +        break;
1302 +    }
1303 +    //UNLOCK_BH(&ip_rtsp_lock);
1304 +
1305 +    return rc;
1306 +}
1307 +
1308 +static void expected(struct nf_conn* ct, struct nf_conntrack_expect *exp)
1309 +{
1310 +    struct nf_nat_multi_range_compat mr;
1311 +    u_int32_t newdstip, newsrcip, newip;
1312 +
1313 +    struct nf_conn *master = ct->master;
1314 +
1315 +    newdstip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
1316 +    newsrcip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
1317 +    //FIXME (how to port that ?)
1318 +    //code from 2.4 : newip = (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC) ? newsrcip : newdstip;
1319 +    newip = newdstip;
1320 +
1321 +    DEBUGP("newsrcip=%u.%u.%u.%u, newdstip=%u.%u.%u.%u, newip=%u.%u.%u.%u\n",
1322 +           NIPQUAD(newsrcip), NIPQUAD(newdstip), NIPQUAD(newip));
1323 +
1324 +    mr.rangesize = 1;
1325 +    // We don't want to manip the per-protocol, just the IPs.
1326 +    mr.range[0].flags = IP_NAT_RANGE_MAP_IPS;
1327 +    mr.range[0].min_ip = mr.range[0].max_ip = newip;
1328 +
1329 +    nf_nat_setup_info(ct, &mr.range[0], IP_NAT_MANIP_DST);
1330 +}
1331 +
1332 +
1333 +static void __exit fini(void)
1334 +{
1335 +       nf_nat_rtsp_hook = NULL;
1336 +        nf_nat_rtsp_hook_expectfn = NULL;
1337 +       synchronize_net();
1338 +}
1339 +
1340 +static int __init init(void)
1341 +{
1342 +       printk("nf_nat_rtsp v" IP_NF_RTSP_VERSION " loading\n");
1343 +
1344 +       BUG_ON(nf_nat_rtsp_hook);
1345 +       nf_nat_rtsp_hook = help;
1346 +        nf_nat_rtsp_hook_expectfn = &expected;
1347 +
1348 +       if (stunaddr != NULL)
1349 +               extip = in_aton(stunaddr);
1350 +
1351 +       if (destaction != NULL) {
1352 +               if (strcmp(destaction, "auto") == 0)
1353 +                       dstact = DSTACT_AUTO;
1354 +
1355 +               if (strcmp(destaction, "strip") == 0)
1356 +                       dstact = DSTACT_STRIP;
1357 +
1358 +               if (strcmp(destaction, "none") == 0)
1359 +                       dstact = DSTACT_NONE;
1360 +       }
1361 +
1362 +       return 0;
1363 +}
1364 +
1365 +module_init(init);
1366 +module_exit(fini);