target/linux/generic-2.6/patches-2.6.22/190-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 **pskb,
  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 @@ -23,6 +23,7 @@
 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-$(CONFIG_NF_NAT_SNMP_BASIC) += nf_nat_snmp_basic.o
 305 --- a/net/netfilter/Kconfig
 306 +++ b/net/netfilter/Kconfig
 307 @@ -239,6 +239,16 @@
 308
 309           To compile it as a module, choose M here.  If unsure, say N.
 310
 311 +config NF_CONNTRACK_RTSP
 312 +       tristate "RTSP protocol support"
 313 +       depends on NF_CONNTRACK
 314 +       help
 315 +               Support the RTSP protocol.  This allows UDP transports to be setup
 316 +               properly, including RTP and RDT.
 317 +
 318 +               If you want to compile it as a module, say 'M' here and read
 319 +               Documentation/modules.txt.  If unsure, say 'Y'.
 320 +
 321  config NF_CT_NETLINK
 322         tristate 'Connection tracking netlink interface (EXPERIMENTAL)'
 323         depends on EXPERIMENTAL && NF_CONNTRACK && NETFILTER_NETLINK
 324 --- a/net/netfilter/Makefile
 325 +++ b/net/netfilter/Makefile
 326 @@ -32,6 +32,7 @@
 327  obj-$(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-$(CONFIG_NF_CONNTRACK_RTSP) += nf_conntrack_rtsp.o
 331
 332  # generic X tables
 333  obj-$(CONFIG_NETFILTER_XTABLES) += x_tables.o xt_tcpudp.o
 334 --- a/net/ipv4/netfilter/Kconfig
 335 +++ b/net/ipv4/netfilter/Kconfig
 336 @@ -296,6 +296,11 @@
 337         depends on IP_NF_IPTABLES && 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 IP_NF_IPTABLES && NF_CONNTRACK && NF_NAT
 348 --- /dev/null
 349 +++ b/net/netfilter/nf_conntrack_rtsp.c
 350 @@ -0,0 +1,515 @@
 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 **pskb,
 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 **pskb, 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_conntrack_expect_alloc(ct);
 675 +               if (!exp) {
 676 +                       ret = NF_DROP;
 677 +                       goto out;
 678 +               }
 679 +
 680 +               be_loport = htons(expinfo.loport);
 681 +
 682 +               nf_conntrack_expect_init(exp, ct->tuplehash[!dir].tuple.src.l3num,
 683 +                       &ct->tuplehash[!dir].tuple.src.u3, &ct->tuplehash[!dir].tuple.dst.u3,
 684 +                       IPPROTO_UDP, NULL, &be_loport);
 685 +
 686 +               exp->master = ct;
 687 +
 688 +               exp->expectfn = expected;
 689 +               exp->flags = 0;
 690 +
 691 +               if (expinfo.pbtype == pb_range) {
 692 +                       DEBUGP("Changing expectation mask to handle multiple ports\n");
 693 +                       exp->mask.dst.u.udp.port  = 0xfffe;
 694 +               }
 695 +
 696 +               DEBUGP("expect_related %u.%u.%u.%u:%u-%u.%u.%u.%u:%u\n",
 697 +                      NIPQUAD(exp->tuple.src.u3.ip),
 698 +                      ntohs(exp->tuple.src.u.udp.port),
 699 +                      NIPQUAD(exp->tuple.dst.u3.ip),
 700 +                      ntohs(exp->tuple.dst.u.udp.port));
 701 +
 702 +               if (nf_nat_rtsp_hook)
 703 +                       /* pass the request off to the nat helper */
 704 +                       ret = nf_nat_rtsp_hook(pskb, ctinfo, hdrsoff, hdrslen, &expinfo, exp);
 705 +               else if (nf_conntrack_expect_related(exp) != 0) {
 706 +                       INFOP("nf_conntrack_expect_related failed\n");
 707 +                       ret  = NF_DROP;
 708 +               }
 709 +               nf_conntrack_expect_put(exp);
 710 +               goto out;
 711 +       }
 712 +out:
 713 +
 714 +       return ret;
 715 +}
 716 +
 717 +
 718 +static inline int
 719 +help_in(struct sk_buff **pskb, size_t pktlen,
 720 + struct nf_conn* ct, enum ip_conntrack_info ctinfo)
 721 +{
 722 + return NF_ACCEPT;
 723 +}
 724 +
 725 +static int help(struct sk_buff **pskb, unsigned int protoff,
 726 +               struct nf_conn *ct, enum ip_conntrack_info ctinfo)
 727 +{
 728 +       struct tcphdr _tcph, *th;
 729 +       unsigned int dataoff, datalen;
 730 +       char *rb_ptr;
 731 +       int ret = NF_DROP;
 732 +
 733 +       /* Until there's been traffic both ways, don't look in packets. */
 734 +       if (ctinfo != IP_CT_ESTABLISHED &&
 735 +           ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) {
 736 +               DEBUGP("conntrackinfo = %u\n", ctinfo);
 737 +               return NF_ACCEPT;
 738 +       }
 739 +
 740 +       /* Not whole TCP header? */
 741 +       th = skb_header_pointer(*pskb,protoff, sizeof(_tcph), &_tcph);
 742 +
 743 +       if (!th)
 744 +               return NF_ACCEPT;
 745 +
 746 +       /* No data ? */
 747 +       dataoff = protoff + th->doff*4;
 748 +       datalen = (*pskb)->len - dataoff;
 749 +       if (dataoff >= (*pskb)->len)
 750 +               return NF_ACCEPT;
 751 +
 752 +       spin_lock_bh(&rtsp_buffer_lock);
 753 +       rb_ptr = skb_header_pointer(*pskb, dataoff,
 754 +                                   (*pskb)->len - dataoff, rtsp_buffer);
 755 +       BUG_ON(rb_ptr == NULL);
 756 +
 757 +#if 0
 758 +       /* Checksum invalid?  Ignore. */
 759 +       /* FIXME: Source route IP option packets --RR */
 760 +       if (tcp_v4_check(tcph, tcplen, iph->saddr, iph->daddr,
 761 +                        csum_partial((char*)tcph, tcplen, 0)))
 762 +       {
 763 +               DEBUGP("bad csum: %p %u %u.%u.%u.%u %u.%u.%u.%u\n",
 764 +                      tcph, tcplen, NIPQUAD(iph->saddr), NIPQUAD(iph->daddr));
 765 +               return NF_ACCEPT;
 766 +       }
 767 +#endif
 768 +
 769 +       switch (CTINFO2DIR(ctinfo)) {
 770 +       case IP_CT_DIR_ORIGINAL:
 771 +               ret = help_out(pskb, rb_ptr, datalen, ct, ctinfo);
 772 +               break;
 773 +       case IP_CT_DIR_REPLY:
 774 +               DEBUGP("IP_CT_DIR_REPLY\n");
 775 +               /* inbound packet: server->client */
 776 +               ret = NF_ACCEPT;
 777 +               break;
 778 +       }
 779 +
 780 +       spin_unlock_bh(&rtsp_buffer_lock);
 781 +
 782 +       return ret;
 783 +}
 784 +
 785 +static struct nf_conntrack_helper rtsp_helpers[MAX_PORTS];
 786 +static char rtsp_names[MAX_PORTS][10];
 787 +
 788 +/* This function is intentionally _NOT_ defined as __exit */
 789 +static void
 790 +fini(void)
 791 +{
 792 +       int i;
 793 +       for (i = 0; i < num_ports; i++) {
 794 +               DEBUGP("unregistering port %d\n", ports[i]);
 795 +               nf_conntrack_helper_unregister(&rtsp_helpers[i]);
 796 +       }
 797 +       kfree(rtsp_buffer);
 798 +}
 799 +
 800 +static int __init
 801 +init(void)
 802 +{
 803 +       int i, ret;
 804 +       struct nf_conntrack_helper *hlpr;
 805 +       char *tmpname;
 806 +
 807 +       printk("nf_conntrack_rtsp v" IP_NF_RTSP_VERSION " loading\n");
 808 +
 809 +       if (max_outstanding < 1) {
 810 +               printk("nf_conntrack_rtsp: max_outstanding must be a positive integer\n");
 811 +               return -EBUSY;
 812 +       }
 813 +       if (setup_timeout < 0) {
 814 +               printk("nf_conntrack_rtsp: setup_timeout must be a positive integer\n");
 815 +               return -EBUSY;
 816 +       }
 817 +
 818 +       rtsp_buffer = kmalloc(65536, GFP_KERNEL);
 819 +       if (!rtsp_buffer)
 820 +               return -ENOMEM;
 821 +
 822 +       /* If no port given, default to standard rtsp port */
 823 +       if (ports[0] == 0) {
 824 +               ports[0] = RTSP_PORT;
 825 +       }
 826 +
 827 +       for (i = 0; (i < MAX_PORTS) && ports[i]; i++) {
 828 +               hlpr = &rtsp_helpers[i];
 829 +               memset(hlpr, 0, sizeof(struct nf_conntrack_helper));
 830 +               hlpr->tuple.src.u.tcp.port = htons(ports[i]);
 831 +               hlpr->tuple.dst.protonum = IPPROTO_TCP;
 832 +               hlpr->mask.src.u.tcp.port = 0xFFFF;
 833 +               hlpr->mask.dst.protonum = 0xFF;
 834 +               hlpr->max_expected = max_outstanding;
 835 +               hlpr->timeout = setup_timeout;
 836 +               hlpr->me = THIS_MODULE;
 837 +               hlpr->help = help;
 838 +
 839 +               tmpname = &rtsp_names[i][0];
 840 +               if (ports[i] == RTSP_PORT) {
 841 +                       sprintf(tmpname, "rtsp");
 842 +               } else {
 843 +                       sprintf(tmpname, "rtsp-%d", i);
 844 +               }
 845 +               hlpr->name = tmpname;
 846 +
 847 +               DEBUGP("port #%d: %d\n", i, ports[i]);
 848 +
 849 +               ret = nf_conntrack_helper_register(hlpr);
 850 +
 851 +               if (ret) {
 852 +                       printk("nf_conntrack_rtsp: ERROR registering port %d\n", ports[i]);
 853 +                       fini();
 854 +                       return -EBUSY;
 855 +               }
 856 +               num_ports++;
 857 +       }
 858 +       return 0;
 859 +}
 860 +
 861 +module_init(init);
 862 +module_exit(fini);
 863 +
 864 +EXPORT_SYMBOL(nf_nat_rtsp_hook_expectfn);
 865 +
 866 --- /dev/null
 867 +++ b/net/ipv4/netfilter/nf_nat_rtsp.c
 868 @@ -0,0 +1,496 @@
 869 +/*
 870 + * RTSP extension for TCP NAT alteration
 871 + * (C) 2003 by Tom Marshall <tmarshall at real.com>
 872 + * based on ip_nat_irc.c
 873 + *
 874 + *      This program is free software; you can redistribute it and/or
 875 + *      modify it under the terms of the GNU General Public License
 876 + *      as published by the Free Software Foundation; either version
 877 + *      2 of the License, or (at your option) any later version.
 878 + *
 879 + * Module load syntax:
 880 + *      insmod nf_nat_rtsp.o ports=port1,port2,...port<MAX_PORTS>
 881 + *                           stunaddr=<address>
 882 + *                           destaction=[auto|strip|none]
 883 + *
 884 + * If no ports are specified, the default will be port 554 only.
 885 + *
 886 + * stunaddr specifies the address used to detect that a client is using STUN.
 887 + * If this address is seen in the destination parameter, it is assumed that
 888 + * the client has already punched a UDP hole in the firewall, so we don't
 889 + * mangle the client_port.  If none is specified, it is autodetected.  It
 890 + * only needs to be set if you have multiple levels of NAT.  It should be
 891 + * set to the external address that the STUN clients detect.  Note that in
 892 + * this case, it will not be possible for clients to use UDP with servers
 893 + * between the NATs.
 894 + *
 895 + * If no destaction is specified, auto is used.
 896 + *   destaction=auto:  strip destination parameter if it is not stunaddr.
 897 + *   destaction=strip: always strip destination parameter (not recommended).
 898 + *   destaction=none:  do not touch destination parameter (not recommended).
 899 + */
 900 +
 901 +#include <linux/module.h>
 902 +#include <net/tcp.h>
 903 +#include <net/netfilter/nf_nat_helper.h>
 904 +#include <net/netfilter/nf_nat_rule.h>
 905 +#include <linux/netfilter/nf_conntrack_rtsp.h>
 906 +#include <net/netfilter/nf_conntrack_expect.h>
 907 +
 908 +#include <linux/inet.h>
 909 +#include <linux/ctype.h>
 910 +#define NF_NEED_STRNCASECMP
 911 +#define NF_NEED_STRTOU16
 912 +#include <linux/netfilter_helpers.h>
 913 +#define NF_NEED_MIME_NEXTLINE
 914 +#include <linux/netfilter_mime.h>
 915 +
 916 +#define INFOP(fmt, args...) printk(KERN_INFO "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args)
 917 +#if 0
 918 +#define DEBUGP(fmt, args...) printk(KERN_DEBUG "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args)
 919 +#else
 920 +#define DEBUGP(fmt, args...)
 921 +#endif
 922 +
 923 +#define MAX_PORTS       8
 924 +#define DSTACT_AUTO     0
 925 +#define DSTACT_STRIP    1
 926 +#define DSTACT_NONE     2
 927 +
 928 +static char*    stunaddr = NULL;
 929 +static char*    destaction = NULL;
 930 +
 931 +static u_int32_t extip = 0;
 932 +static int       dstact = 0;
 933 +
 934 +MODULE_AUTHOR("Tom Marshall <tmarshall at real.com>");
 935 +MODULE_DESCRIPTION("RTSP network address translation module");
 936 +MODULE_LICENSE("GPL");
 937 +module_param(stunaddr, charp, 0644);
 938 +MODULE_PARM_DESC(stunaddr, "Address for detecting STUN");
 939 +module_param(destaction, charp, 0644);
 940 +MODULE_PARM_DESC(destaction, "Action for destination parameter (auto/strip/none)");
 941 +
 942 +#define SKIP_WSPACE(ptr,len,off) while(off < len && isspace(*(ptr+off))) { off++; }
 943 +
 944 +/*** helper functions ***/
 945 +
 946 +static void
 947 +get_skb_tcpdata(struct sk_buff* skb, char** pptcpdata, uint* ptcpdatalen)
 948 +{
 949 +    struct iphdr*   iph  = ip_hdr(skb);
 950 +    struct tcphdr*  tcph = (void *)iph + ip_hdrlen(skb);
 951 +
 952 +    *pptcpdata = (char*)tcph +  tcph->doff*4;
 953 +    *ptcpdatalen = ((char*)skb_transport_header(skb) + skb->len) - *pptcpdata;
 954 +}
 955 +
 956 +/*** nat functions ***/
 957 +
 958 +/*
 959 + * Mangle the "Transport:" header:
 960 + *   - Replace all occurences of "client_port=<spec>"
 961 + *   - Handle destination parameter
 962 + *
 963 + * In:
 964 + *   ct, ctinfo = conntrack context
 965 + *   pskb       = packet
 966 + *   tranoff    = Transport header offset from TCP data
 967 + *   tranlen    = Transport header length (incl. CRLF)
 968 + *   rport_lo   = replacement low  port (host endian)
 969 + *   rport_hi   = replacement high port (host endian)
 970 + *
 971 + * Returns packet size difference.
 972 + *
 973 + * Assumes that a complete transport header is present, ending with CR or LF
 974 + */
 975 +static int
 976 +rtsp_mangle_tran(enum ip_conntrack_info ctinfo,
 977 +                 struct nf_conntrack_expect* exp,
 978 +                                                                struct ip_ct_rtsp_expect* prtspexp,
 979 +                 struct sk_buff** pskb, uint tranoff, uint tranlen)
 980 +{
 981 +    char*       ptcp;
 982 +    uint        tcplen;
 983 +    char*       ptran;
 984 +    char        rbuf1[16];      /* Replacement buffer (one port) */
 985 +    uint        rbuf1len;       /* Replacement len (one port) */
 986 +    char        rbufa[16];      /* Replacement buffer (all ports) */
 987 +    uint        rbufalen;       /* Replacement len (all ports) */
 988 +    u_int32_t   newip;
 989 +    u_int16_t   loport, hiport;
 990 +    uint        off = 0;
 991 +    uint        diff;           /* Number of bytes we removed */
 992 +
 993 +    struct nf_conn *ct = exp->master;
 994 +    struct nf_conntrack_tuple *t;
 995 +
 996 +    char    szextaddr[15+1];
 997 +    uint    extaddrlen;
 998 +    int     is_stun;
 999 +
1000 +    get_skb_tcpdata(*pskb, &ptcp, &tcplen);
1001 +    ptran = ptcp+tranoff;
1002 +
1003 +    if (tranoff+tranlen > tcplen || tcplen-tranoff < tranlen ||
1004 +        tranlen < 10 || !iseol(ptran[tranlen-1]) ||
1005 +        nf_strncasecmp(ptran, "Transport:", 10) != 0)
1006 +    {
1007 +        INFOP("sanity check failed\n");
1008 +        return 0;
1009 +    }
1010 +    off += 10;
1011 +    SKIP_WSPACE(ptcp+tranoff, tranlen, off);
1012 +
1013 +    newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip;
1014 +    t = &exp->tuple;
1015 +    t->dst.u3.ip = newip;
1016 +
1017 +    extaddrlen = extip ? sprintf(szextaddr, "%u.%u.%u.%u", NIPQUAD(extip))
1018 +                       : sprintf(szextaddr, "%u.%u.%u.%u", NIPQUAD(newip));
1019 +    DEBUGP("stunaddr=%s (%s)\n", szextaddr, (extip?"forced":"auto"));
1020 +
1021 +    rbuf1len = rbufalen = 0;
1022 +    switch (prtspexp->pbtype)
1023 +    {
1024 +    case pb_single:
1025 +        for (loport = prtspexp->loport; loport != 0; loport++) /* XXX: improper wrap? */
1026 +        {
1027 +            t->dst.u.udp.port = htons(loport);
1028 +            if (nf_conntrack_expect_related(exp) == 0)
1029 +            {
1030 +                DEBUGP("using port %hu\n", loport);
1031 +                break;
1032 +            }
1033 +        }
1034 +        if (loport != 0)
1035 +        {
1036 +            rbuf1len = sprintf(rbuf1, "%hu", loport);
1037 +            rbufalen = sprintf(rbufa, "%hu", loport);
1038 +        }
1039 +        break;
1040 +    case pb_range:
1041 +        for (loport = prtspexp->loport; loport != 0; loport += 2) /* XXX: improper wrap? */
1042 +        {
1043 +            t->dst.u.udp.port = htons(loport);
1044 +            if (nf_conntrack_expect_related(exp) == 0)
1045 +            {
1046 +                hiport = loport + ~exp->mask.dst.u.udp.port;
1047 +                DEBUGP("using ports %hu-%hu\n", loport, hiport);
1048 +                break;
1049 +            }
1050 +        }
1051 +        if (loport != 0)
1052 +        {
1053 +            rbuf1len = sprintf(rbuf1, "%hu", loport);
1054 +            rbufalen = sprintf(rbufa, "%hu-%hu", loport, loport+1);
1055 +        }
1056 +        break;
1057 +    case pb_discon:
1058 +        for (loport = prtspexp->loport; loport != 0; loport++) /* XXX: improper wrap? */
1059 +        {
1060 +            t->dst.u.udp.port = htons(loport);
1061 +            if (nf_conntrack_expect_related(exp) == 0)
1062 +            {
1063 +                DEBUGP("using port %hu (1 of 2)\n", loport);
1064 +                break;
1065 +            }
1066 +        }
1067 +        for (hiport = prtspexp->hiport; hiport != 0; hiport++) /* XXX: improper wrap? */
1068 +        {
1069 +            t->dst.u.udp.port = htons(hiport);
1070 +            if (nf_conntrack_expect_related(exp) == 0)
1071 +            {
1072 +                DEBUGP("using port %hu (2 of 2)\n", hiport);
1073 +                break;
1074 +            }
1075 +        }
1076 +        if (loport != 0 && hiport != 0)
1077 +        {
1078 +            rbuf1len = sprintf(rbuf1, "%hu", loport);
1079 +            if (hiport == loport+1)
1080 +            {
1081 +                rbufalen = sprintf(rbufa, "%hu-%hu", loport, hiport);
1082 +            }
1083 +            else
1084 +            {
1085 +                rbufalen = sprintf(rbufa, "%hu/%hu", loport, hiport);
1086 +            }
1087 +        }
1088 +        break;
1089 +    }
1090 +
1091 +    if (rbuf1len == 0)
1092 +    {
1093 +        return 0;   /* cannot get replacement port(s) */
1094 +    }
1095 +
1096 +    /* Transport: tran;field;field=val,tran;field;field=val,... */
1097 +    while (off < tranlen)
1098 +    {
1099 +        uint        saveoff;
1100 +        const char* pparamend;
1101 +        uint        nextparamoff;
1102 +
1103 +        pparamend = memchr(ptran+off, ',', tranlen-off);
1104 +        pparamend = (pparamend == NULL) ? ptran+tranlen : pparamend+1;
1105 +        nextparamoff = pparamend-ptcp;
1106 +
1107 +        /*
1108 +         * We pass over each param twice.  On the first pass, we look for a
1109 +         * destination= field.  It is handled by the security policy.  If it
1110 +         * is present, allowed, and equal to our external address, we assume
1111 +         * that STUN is being used and we leave the client_port= field alone.
1112 +         */
1113 +        is_stun = 0;
1114 +        saveoff = off;
1115 +        while (off < nextparamoff)
1116 +        {
1117 +            const char* pfieldend;
1118 +            uint        nextfieldoff;
1119 +
1120 +            pfieldend = memchr(ptran+off, ';', nextparamoff-off);
1121 +            nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
1122 +
1123 +            if (dstact != DSTACT_NONE && strncmp(ptran+off, "destination=", 12) == 0)
1124 +            {
1125 +                if (strncmp(ptran+off+12, szextaddr, extaddrlen) == 0)
1126 +                {
1127 +                    is_stun = 1;
1128 +                }
1129 +                if (dstact == DSTACT_STRIP || (dstact == DSTACT_AUTO && !is_stun))
1130 +                {
1131 +                    diff = nextfieldoff-off;
1132 +                    if (!nf_nat_mangle_tcp_packet(pskb, ct, ctinfo,
1133 +                                                         off, diff, NULL, 0))
1134 +                    {
1135 +                        /* mangle failed, all we can do is bail */
1136 +                       nf_conntrack_unexpect_related(exp);
1137 +                        return 0;
1138 +                    }
1139 +                    get_skb_tcpdata(*pskb, &ptcp, &tcplen);
1140 +                    ptran = ptcp+tranoff;
1141 +                    tranlen -= diff;
1142 +                    nextparamoff -= diff;
1143 +                    nextfieldoff -= diff;
1144 +                }
1145 +            }
1146 +
1147 +            off = nextfieldoff;
1148 +        }
1149 +        if (is_stun)
1150 +        {
1151 +            continue;
1152 +        }
1153 +        off = saveoff;
1154 +        while (off < nextparamoff)
1155 +        {
1156 +            const char* pfieldend;
1157 +            uint        nextfieldoff;
1158 +
1159 +            pfieldend = memchr(ptran+off, ';', nextparamoff-off);
1160 +            nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
1161 +
1162 +            if (strncmp(ptran+off, "client_port=", 12) == 0)
1163 +            {
1164 +                u_int16_t   port;
1165 +                uint        numlen;
1166 +                uint        origoff;
1167 +                uint        origlen;
1168 +                char*       rbuf    = rbuf1;
1169 +                uint        rbuflen = rbuf1len;
1170 +
1171 +                off += 12;
1172 +                origoff = (ptran-ptcp)+off;
1173 +                origlen = 0;
1174 +                numlen = nf_strtou16(ptran+off, &port);
1175 +                off += numlen;
1176 +                origlen += numlen;
1177 +                if (port != prtspexp->loport)
1178 +                {
1179 +                    DEBUGP("multiple ports found, port %hu ignored\n", port);
1180 +                }
1181 +                else
1182 +                {
1183 +                    if (ptran[off] == '-' || ptran[off] == '/')
1184 +                    {
1185 +                        off++;
1186 +                        origlen++;
1187 +                        numlen = nf_strtou16(ptran+off, &port);
1188 +                        off += numlen;
1189 +                        origlen += numlen;
1190 +                        rbuf = rbufa;
1191 +                        rbuflen = rbufalen;
1192 +                    }
1193 +
1194 +                    /*
1195 +                     * note we cannot just memcpy() if the sizes are the same.
1196 +                     * the mangle function does skb resizing, checks for a
1197 +                     * cloned skb, and updates the checksums.
1198 +                     *
1199 +                     * parameter 4 below is offset from start of tcp data.
1200 +                     */
1201 +                    diff = origlen-rbuflen;
1202 +                    if (!nf_nat_mangle_tcp_packet(pskb, ct, ctinfo,
1203 +                                              origoff, origlen, rbuf, rbuflen))
1204 +                    {
1205 +                        /* mangle failed, all we can do is bail */
1206 +                       nf_conntrack_unexpect_related(exp);
1207 +                        return 0;
1208 +                    }
1209 +                    get_skb_tcpdata(*pskb, &ptcp, &tcplen);
1210 +                    ptran = ptcp+tranoff;
1211 +                    tranlen -= diff;
1212 +                    nextparamoff -= diff;
1213 +                    nextfieldoff -= diff;
1214 +                }
1215 +            }
1216 +
1217 +            off = nextfieldoff;
1218 +        }
1219 +
1220 +        off = nextparamoff;
1221 +    }
1222 +
1223 +    return 1;
1224 +}
1225 +
1226 +static uint
1227 +help_out(struct sk_buff **pskb, enum ip_conntrack_info ctinfo,
1228 +        unsigned int matchoff, unsigned int matchlen, struct ip_ct_rtsp_expect* prtspexp,
1229 +        struct nf_conntrack_expect* exp)
1230 +{
1231 +    char*   ptcp;
1232 +    uint    tcplen;
1233 +    uint    hdrsoff;
1234 +    uint    hdrslen;
1235 +    uint    lineoff;
1236 +    uint    linelen;
1237 +    uint    off;
1238 +
1239 +    //struct iphdr* iph = (struct iphdr*)(*pskb)->nh.iph;
1240 +    //struct tcphdr* tcph = (struct tcphdr*)((void*)iph + iph->ihl*4);
1241 +
1242 +    get_skb_tcpdata(*pskb, &ptcp, &tcplen);
1243 +    hdrsoff = matchoff;//exp->seq - ntohl(tcph->seq);
1244 +    hdrslen = matchlen;
1245 +    off = hdrsoff;
1246 +    DEBUGP("NAT rtsp help_out\n");
1247 +
1248 +    while (nf_mime_nextline(ptcp, hdrsoff+hdrslen, &off, &lineoff, &linelen))
1249 +    {
1250 +        if (linelen == 0)
1251 +        {
1252 +            break;
1253 +        }
1254 +        if (off > hdrsoff+hdrslen)
1255 +        {
1256 +            INFOP("!! overrun !!");
1257 +            break;
1258 +        }
1259 +        DEBUGP("hdr: len=%u, %.*s", linelen, (int)linelen, ptcp+lineoff);
1260 +
1261 +        if (nf_strncasecmp(ptcp+lineoff, "Transport:", 10) == 0)
1262 +        {
1263 +            uint oldtcplen = tcplen;
1264 +           DEBUGP("hdr: Transport\n");
1265 +            if (!rtsp_mangle_tran(ctinfo, exp, prtspexp, pskb, lineoff, linelen))
1266 +            {
1267 +               DEBUGP("hdr: Transport mangle failed");
1268 +                break;
1269 +            }
1270 +            get_skb_tcpdata(*pskb, &ptcp, &tcplen);
1271 +            hdrslen -= (oldtcplen-tcplen);
1272 +            off -= (oldtcplen-tcplen);
1273 +            lineoff -= (oldtcplen-tcplen);
1274 +            linelen -= (oldtcplen-tcplen);
1275 +            DEBUGP("rep: len=%u, %.*s", linelen, (int)linelen, ptcp+lineoff);
1276 +        }
1277 +    }
1278 +
1279 +    return NF_ACCEPT;
1280 +}
1281 +
1282 +static unsigned int
1283 +help(struct sk_buff **pskb, enum ip_conntrack_info ctinfo,
1284 +     unsigned int matchoff, unsigned int matchlen, struct ip_ct_rtsp_expect* prtspexp,
1285 +     struct nf_conntrack_expect* exp)
1286 +{
1287 +    int dir = CTINFO2DIR(ctinfo);
1288 +    int rc = NF_ACCEPT;
1289 +
1290 +    switch (dir)
1291 +    {
1292 +    case IP_CT_DIR_ORIGINAL:
1293 +        rc = help_out(pskb, ctinfo, matchoff, matchlen, prtspexp, exp);
1294 +        break;
1295 +    case IP_CT_DIR_REPLY:
1296 +       DEBUGP("unmangle ! %u\n", ctinfo);
1297 +       /* XXX: unmangle */
1298 +       rc = NF_ACCEPT;
1299 +        break;
1300 +    }
1301 +    //UNLOCK_BH(&ip_rtsp_lock);
1302 +
1303 +    return rc;
1304 +}
1305 +
1306 +static void expected(struct nf_conn* ct, struct nf_conntrack_expect *exp)
1307 +{
1308 +    struct nf_nat_multi_range_compat mr;
1309 +    u_int32_t newdstip, newsrcip, newip;
1310 +
1311 +    struct nf_conn *master = ct->master;
1312 +
1313 +    newdstip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
1314 +    newsrcip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
1315 +    //FIXME (how to port that ?)
1316 +    //code from 2.4 : newip = (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC) ? newsrcip : newdstip;
1317 +    newip = newdstip;
1318 +
1319 +    DEBUGP("newsrcip=%u.%u.%u.%u, newdstip=%u.%u.%u.%u, newip=%u.%u.%u.%u\n",
1320 +           NIPQUAD(newsrcip), NIPQUAD(newdstip), NIPQUAD(newip));
1321 +
1322 +    mr.rangesize = 1;
1323 +    // We don't want to manip the per-protocol, just the IPs.
1324 +    mr.range[0].flags = IP_NAT_RANGE_MAP_IPS;
1325 +    mr.range[0].min_ip = mr.range[0].max_ip = newip;
1326 +
1327 +    nf_nat_setup_info(ct, &mr.range[0], NF_IP_PRE_ROUTING);
1328 +}
1329 +
1330 +
1331 +static void __exit fini(void)
1332 +{
1333 +       nf_nat_rtsp_hook = NULL;
1334 +        nf_nat_rtsp_hook_expectfn = NULL;
1335 +       synchronize_net();
1336 +}
1337 +
1338 +static int __init init(void)
1339 +{
1340 +       printk("nf_nat_rtsp v" IP_NF_RTSP_VERSION " loading\n");
1341 +
1342 +       BUG_ON(nf_nat_rtsp_hook);
1343 +       nf_nat_rtsp_hook = help;
1344 +        nf_nat_rtsp_hook_expectfn = &expected;
1345 +
1346 +       if (stunaddr != NULL)
1347 +               extip = in_aton(stunaddr);
1348 +
1349 +       if (destaction != NULL) {
1350 +               if (strcmp(destaction, "auto") == 0)
1351 +                       dstact = DSTACT_AUTO;
1352 +
1353 +               if (strcmp(destaction, "strip") == 0)
1354 +                       dstact = DSTACT_STRIP;
1355 +
1356 +               if (strcmp(destaction, "none") == 0)
1357 +                       dstact = DSTACT_NONE;
1358 +       }
1359 +
1360 +       return 0;
1361 +}
1362 +
1363 +module_init(init);
1364 +module_exit(fini);