package/network/utils/xtables-addons/patches/100-add-rtsp-conntrack.patch

   1 --- /dev/null
   2 +++ b/extensions/rtsp/Kbuild
   3 @@ -0,0 +1,4 @@
   4 +# -*- Makefile -*-
   5 +
   6 +obj-m += nf_nat_rtsp.o
   7 +obj-m += nf_conntrack_rtsp.o
   8 --- /dev/null
   9 +++ b/extensions/rtsp/netfilter_helpers.h
  10 @@ -0,0 +1,133 @@
  11 +/*
  12 + * Helpers for netfiler modules.  This file provides implementations for basic
  13 + * functions such as strncasecmp(), etc.
  14 + *
  15 + * gcc will warn for defined but unused functions, so we only include the
  16 + * functions requested.  The following macros are used:
  17 + *   NF_NEED_STRNCASECMP        nf_strncasecmp()
  18 + *   NF_NEED_STRTOU16           nf_strtou16()
  19 + *   NF_NEED_STRTOU32           nf_strtou32()
  20 + */
  21 +#ifndef _NETFILTER_HELPERS_H
  22 +#define _NETFILTER_HELPERS_H
  23 +
  24 +/* Only include these functions for kernel code. */
  25 +#ifdef __KERNEL__
  26 +
  27 +#include <linux/ctype.h>
  28 +#define iseol(c) ( (c) == '\r' || (c) == '\n' )
  29 +
  30 +/*
  31 + * The standard strncasecmp()
  32 + */
  33 +#ifdef NF_NEED_STRNCASECMP
  34 +static int
  35 +nf_strncasecmp(const char* s1, const char* s2, u_int32_t len)
  36 +{
  37 +    if (s1 == NULL || s2 == NULL)
  38 +    {
  39 +        if (s1 == NULL && s2 == NULL)
  40 +        {
  41 +            return 0;
  42 +        }
  43 +        return (s1 == NULL) ? -1 : 1;
  44 +    }
  45 +    while (len > 0 && tolower(*s1) == tolower(*s2))
  46 +    {
  47 +        len--;
  48 +        s1++;
  49 +        s2++;
  50 +    }
  51 +    return ( (len == 0) ? 0 : (tolower(*s1) - tolower(*s2)) );
  52 +}
  53 +#endif /* NF_NEED_STRNCASECMP */
  54 +
  55 +/*
  56 + * Parse a string containing a 16-bit unsigned integer.
  57 + * Returns the number of chars used, or zero if no number is found.
  58 + */
  59 +#ifdef NF_NEED_STRTOU16
  60 +static int
  61 +nf_strtou16(const char* pbuf, u_int16_t* pval)
  62 +{
  63 +    int n = 0;
  64 +
  65 +    *pval = 0;
  66 +    while (isdigit(pbuf[n]))
  67 +    {
  68 +        *pval = (*pval * 10) + (pbuf[n] - '0');
  69 +        n++;
  70 +    }
  71 +
  72 +    return n;
  73 +}
  74 +#endif /* NF_NEED_STRTOU16 */
  75 +
  76 +/*
  77 + * Parse a string containing a 32-bit unsigned integer.
  78 + * Returns the number of chars used, or zero if no number is found.
  79 + */
  80 +#ifdef NF_NEED_STRTOU32
  81 +static int
  82 +nf_strtou32(const char* pbuf, u_int32_t* pval)
  83 +{
  84 +    int n = 0;
  85 +
  86 +    *pval = 0;
  87 +    while (pbuf[n] >= '0' && pbuf[n] <= '9')
  88 +    {
  89 +        *pval = (*pval * 10) + (pbuf[n] - '0');
  90 +        n++;
  91 +    }
  92 +
  93 +    return n;
  94 +}
  95 +#endif /* NF_NEED_STRTOU32 */
  96 +
  97 +/*
  98 + * Given a buffer and length, advance to the next line and mark the current
  99 + * line.
 100 + */
 101 +#ifdef NF_NEED_NEXTLINE
 102 +static int
 103 +nf_nextline(char* p, uint len, uint* poff, uint* plineoff, uint* plinelen)
 104 +{
 105 +    uint    off = *poff;
 106 +    uint    physlen = 0;
 107 +
 108 +    if (off >= len)
 109 +    {
 110 +        return 0;
 111 +    }
 112 +
 113 +    while (p[off] != '\n')
 114 +    {
 115 +        if (len-off <= 1)
 116 +        {
 117 +            return 0;
 118 +        }
 119 +
 120 +        physlen++;
 121 +        off++;
 122 +    }
 123 +
 124 +    /* if we saw a crlf, physlen needs adjusted */
 125 +    if (physlen > 0 && p[off] == '\n' && p[off-1] == '\r')
 126 +    {
 127 +        physlen--;
 128 +    }
 129 +
 130 +    /* advance past the newline */
 131 +    off++;
 132 +
 133 +    *plineoff = *poff;
 134 +    *plinelen = physlen;
 135 +    *poff = off;
 136 +
 137 +    return 1;
 138 +}
 139 +#endif /* NF_NEED_NEXTLINE */
 140 +
 141 +#endif /* __KERNEL__ */
 142 +
 143 +#endif /* _NETFILTER_HELPERS_H */
 144 --- /dev/null
 145 +++ b/extensions/rtsp/netfilter_mime.h
 146 @@ -0,0 +1,89 @@
 147 +/*
 148 + * MIME functions for netfilter modules.  This file provides implementations
 149 + * for basic MIME parsing.  MIME headers are used in many protocols, such as
 150 + * HTTP, RTSP, SIP, etc.
 151 + *
 152 + * gcc will warn for defined but unused functions, so we only include the
 153 + * functions requested.  The following macros are used:
 154 + *   NF_NEED_MIME_NEXTLINE      nf_mime_nextline()
 155 + */
 156 +#ifndef _NETFILTER_MIME_H
 157 +#define _NETFILTER_MIME_H
 158 +
 159 +/* Only include these functions for kernel code. */
 160 +#ifdef __KERNEL__
 161 +
 162 +#include <linux/ctype.h>
 163 +
 164 +/*
 165 + * Given a buffer and length, advance to the next line and mark the current
 166 + * line.  If the current line is empty, *plinelen will be set to zero.  If
 167 + * not, it will be set to the actual line length (including CRLF).
 168 + *
 169 + * 'line' in this context means logical line (includes LWS continuations).
 170 + * Returns 1 on success, 0 on failure.
 171 + */
 172 +#ifdef NF_NEED_MIME_NEXTLINE
 173 +static int
 174 +nf_mime_nextline(char* p, uint len, uint* poff, uint* plineoff, uint* plinelen)
 175 +{
 176 +    uint    off = *poff;
 177 +    uint    physlen = 0;
 178 +    int     is_first_line = 1;
 179 +
 180 +    if (off >= len)
 181 +    {
 182 +        return 0;
 183 +    }
 184 +
 185 +    do
 186 +    {
 187 +        while (p[off] != '\n')
 188 +        {
 189 +            if (len-off <= 1)
 190 +            {
 191 +                return 0;
 192 +            }
 193 +
 194 +            physlen++;
 195 +            off++;
 196 +        }
 197 +
 198 +        /* if we saw a crlf, physlen needs adjusted */
 199 +        if (physlen > 0 && p[off] == '\n' && p[off-1] == '\r')
 200 +        {
 201 +            physlen--;
 202 +        }
 203 +
 204 +        /* advance past the newline */
 205 +        off++;
 206 +
 207 +        /* check for an empty line */
 208 +        if (physlen == 0)
 209 +        {
 210 +            break;
 211 +        }
 212 +
 213 +        /* check for colon on the first physical line */
 214 +        if (is_first_line)
 215 +        {
 216 +            is_first_line = 0;
 217 +            if (memchr(p+(*poff), ':', physlen) == NULL)
 218 +            {
 219 +                return 0;
 220 +            }
 221 +        }
 222 +    }
 223 +    while (p[off] == ' ' || p[off] == '\t');
 224 +
 225 +    *plineoff = *poff;
 226 +    *plinelen = (physlen == 0) ? 0 : (off - *poff);
 227 +    *poff = off;
 228 +
 229 +    return 1;
 230 +}
 231 +#endif /* NF_NEED_MIME_NEXTLINE */
 232 +
 233 +#endif /* __KERNEL__ */
 234 +
 235 +#endif /* _NETFILTER_MIME_H */
 236 --- /dev/null
 237 +++ b/extensions/rtsp/nf_conntrack_rtsp.c
 238 @@ -0,0 +1,519 @@
 239 +/*
 240 + * RTSP extension for IP connection tracking
 241 + * (C) 2003 by Tom Marshall <tmarshall at real.com>
 242 + * based on ip_conntrack_irc.c
 243 + *
 244 + *      This program is free software; you can redistribute it and/or
 245 + *      modify it under the terms of the GNU General Public License
 246 + *      as published by the Free Software Foundation; either version
 247 + *      2 of the License, or (at your option) any later version.
 248 + *
 249 + * Module load syntax:
 250 + *   insmod nf_conntrack_rtsp.o ports=port1,port2,...port<MAX_PORTS>
 251 + *                              max_outstanding=n setup_timeout=secs
 252 + *
 253 + * If no ports are specified, the default will be port 554.
 254 + *
 255 + * With max_outstanding you can define the maximum number of not yet
 256 + * answered SETUP requests per RTSP session (default 8).
 257 + * With setup_timeout you can specify how long the system waits for
 258 + * an expected data channel (default 300 seconds).
 259 + *
 260 + * 2005-02-13: Harald Welte <laforge at netfilter.org>
 261 + *     - port to 2.6
 262 + *     - update to recent post-2.6.11 api changes
 263 + * 2006-09-14: Steven Van Acker <deepstar at singularity.be>
 264 + *      - removed calls to NAT code from conntrack helper: NAT no longer needed to use rtsp-conntrack
 265 + * 2007-04-18: Michael Guntsche <mike at it-loops.com>
 266 + *                     - Port to new NF API
 267 + */
 268 +
 269 +#include <linux/module.h>
 270 +#include <linux/netfilter.h>
 271 +#include <linux/ip.h>
 272 +#include <linux/inet.h>
 273 +#include <net/tcp.h>
 274 +
 275 +#include <net/netfilter/nf_conntrack.h>
 276 +#include <net/netfilter/nf_conntrack_expect.h>
 277 +#include <net/netfilter/nf_conntrack_helper.h>
 278 +#include "nf_conntrack_rtsp.h"
 279 +
 280 +#define NF_NEED_STRNCASECMP
 281 +#define NF_NEED_STRTOU16
 282 +#define NF_NEED_STRTOU32
 283 +#define NF_NEED_NEXTLINE
 284 +#include "netfilter_helpers.h"
 285 +#define NF_NEED_MIME_NEXTLINE
 286 +#include "netfilter_mime.h"
 287 +
 288 +#include <linux/ctype.h>
 289 +#define MAX_SIMUL_SETUP 8 /* XXX: use max_outstanding */
 290 +
 291 +#define MAX_PORTS 8
 292 +static int ports[MAX_PORTS];
 293 +static int num_ports = 0;
 294 +static int max_outstanding = 8;
 295 +static unsigned int setup_timeout = 300;
 296 +
 297 +MODULE_AUTHOR("Tom Marshall <tmarshall at real.com>");
 298 +MODULE_DESCRIPTION("RTSP connection tracking module");
 299 +MODULE_LICENSE("GPL");
 300 +module_param_array(ports, int, &num_ports, 0400);
 301 +MODULE_PARM_DESC(ports, "port numbers of RTSP servers");
 302 +module_param(max_outstanding, int, 0400);
 303 +MODULE_PARM_DESC(max_outstanding, "max number of outstanding SETUP requests per RTSP session");
 304 +module_param(setup_timeout, int, 0400);
 305 +MODULE_PARM_DESC(setup_timeout, "timeout on for unestablished data channels");
 306 +
 307 +static char *rtsp_buffer;
 308 +static DEFINE_SPINLOCK(rtsp_buffer_lock);
 309 +
 310 +static struct nf_conntrack_expect_policy rtsp_exp_policy;
 311 +
 312 +unsigned int (*nf_nat_rtsp_hook)(struct sk_buff *skb,
 313 +                                enum ip_conntrack_info ctinfo,
 314 +                                unsigned int matchoff, unsigned int matchlen,struct ip_ct_rtsp_expect* prtspexp,
 315 +                                struct nf_conntrack_expect *exp);
 316 +void (*nf_nat_rtsp_hook_expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp);
 317 +
 318 +EXPORT_SYMBOL_GPL(nf_nat_rtsp_hook);
 319 +
 320 +/*
 321 + * Max mappings we will allow for one RTSP connection (for RTP, the number
 322 + * of allocated ports is twice this value).  Note that SMIL burns a lot of
 323 + * ports so keep this reasonably high.  If this is too low, you will see a
 324 + * lot of "no free client map entries" messages.
 325 + */
 326 +#define MAX_PORT_MAPS 16
 327 +
 328 +/*** default port list was here in the masq code: 554, 3030, 4040 ***/
 329 +
 330 +#define SKIP_WSPACE(ptr,len,off) while(off < len && isspace(*(ptr+off))) { off++; }
 331 +
 332 +/*
 333 + * Parse an RTSP packet.
 334 + *
 335 + * Returns zero if parsing failed.
 336 + *
 337 + * Parameters:
 338 + *  IN      ptcp        tcp data pointer
 339 + *  IN      tcplen      tcp data len
 340 + *  IN/OUT  ptcpoff     points to current tcp offset
 341 + *  OUT     phdrsoff    set to offset of rtsp headers
 342 + *  OUT     phdrslen    set to length of rtsp headers
 343 + *  OUT     pcseqoff    set to offset of CSeq header
 344 + *  OUT     pcseqlen    set to length of CSeq header
 345 + */
 346 +static int
 347 +rtsp_parse_message(char* ptcp, uint tcplen, uint* ptcpoff,
 348 +                   uint* phdrsoff, uint* phdrslen,
 349 +                   uint* pcseqoff, uint* pcseqlen,
 350 +                   uint* transoff, uint* translen)
 351 +{
 352 +       uint    entitylen = 0;
 353 +       uint    lineoff;
 354 +       uint    linelen;
 355 +
 356 +       if (!nf_nextline(ptcp, tcplen, ptcpoff, &lineoff, &linelen))
 357 +               return 0;
 358 +
 359 +       *phdrsoff = *ptcpoff;
 360 +       while (nf_mime_nextline(ptcp, tcplen, ptcpoff, &lineoff, &linelen)) {
 361 +               if (linelen == 0) {
 362 +                       if (entitylen > 0)
 363 +                               *ptcpoff += min(entitylen, tcplen - *ptcpoff);
 364 +                       break;
 365 +               }
 366 +               if (lineoff+linelen > tcplen) {
 367 +                       pr_info("!! overrun !!\n");
 368 +                       break;
 369 +               }
 370 +
 371 +               if (nf_strncasecmp(ptcp+lineoff, "CSeq:", 5) == 0) {
 372 +                       *pcseqoff = lineoff;
 373 +                       *pcseqlen = linelen;
 374 +               }
 375 +
 376 +               if (nf_strncasecmp(ptcp+lineoff, "Transport:", 10) == 0) {
 377 +                       *transoff = lineoff;
 378 +                       *translen = linelen;
 379 +               }
 380 +
 381 +               if (nf_strncasecmp(ptcp+lineoff, "Content-Length:", 15) == 0) {
 382 +                       uint off = lineoff+15;
 383 +                       SKIP_WSPACE(ptcp+lineoff, linelen, off);
 384 +                       nf_strtou32(ptcp+off, &entitylen);
 385 +               }
 386 +       }
 387 +       *phdrslen = (*ptcpoff) - (*phdrsoff);
 388 +
 389 +       return 1;
 390 +}
 391 +
 392 +/*
 393 + * Find lo/hi client ports (if any) in transport header
 394 + * In:
 395 + *   ptcp, tcplen = packet
 396 + *   tranoff, tranlen = buffer to search
 397 + *
 398 + * Out:
 399 + *   pport_lo, pport_hi = lo/hi ports (host endian)
 400 + *
 401 + * Returns nonzero if any client ports found
 402 + *
 403 + * Note: it is valid (and expected) for the client to request multiple
 404 + * transports, so we need to parse the entire line.
 405 + */
 406 +static int
 407 +rtsp_parse_transport(char* ptran, uint tranlen,
 408 +                     struct ip_ct_rtsp_expect* prtspexp)
 409 +{
 410 +       int     rc = 0;
 411 +       uint    off = 0;
 412 +
 413 +       if (tranlen < 10 || !iseol(ptran[tranlen-1]) ||
 414 +           nf_strncasecmp(ptran, "Transport:", 10) != 0) {
 415 +               pr_info("sanity check failed\n");
 416 +               return 0;
 417 +       }
 418 +
 419 +       pr_debug("tran='%.*s'\n", (int)tranlen, ptran);
 420 +       off += 10;
 421 +       SKIP_WSPACE(ptran, tranlen, off);
 422 +
 423 +       /* Transport: tran;field;field=val,tran;field;field=val,... */
 424 +       while (off < tranlen) {
 425 +               const char* pparamend;
 426 +               uint        nextparamoff;
 427 +
 428 +               pparamend = memchr(ptran+off, ',', tranlen-off);
 429 +               pparamend = (pparamend == NULL) ? ptran+tranlen : pparamend+1;
 430 +               nextparamoff = pparamend-ptran;
 431 +
 432 +               while (off < nextparamoff) {
 433 +                       const char* pfieldend;
 434 +                       uint        nextfieldoff;
 435 +
 436 +                       pfieldend = memchr(ptran+off, ';', nextparamoff-off);
 437 +                       nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
 438 +
 439 +                       if (strncmp(ptran+off, "client_port=", 12) == 0) {
 440 +                               u_int16_t   port;
 441 +                               uint        numlen;
 442 +
 443 +                               off += 12;
 444 +                               numlen = nf_strtou16(ptran+off, &port);
 445 +                               off += numlen;
 446 +                               if (prtspexp->loport != 0 && prtspexp->loport != port)
 447 +                                       pr_debug("multiple ports found, port %hu ignored\n", port);
 448 +                               else {
 449 +                                       pr_debug("lo port found : %hu\n", port);
 450 +                                       prtspexp->loport = prtspexp->hiport = port;
 451 +                                       if (ptran[off] == '-') {
 452 +                                               off++;
 453 +                                               numlen = nf_strtou16(ptran+off, &port);
 454 +                                               off += numlen;
 455 +                                               prtspexp->pbtype = pb_range;
 456 +                                               prtspexp->hiport = port;
 457 +
 458 +                                               // If we have a range, assume rtp:
 459 +                                               // loport must be even, hiport must be loport+1
 460 +                                               if ((prtspexp->loport & 0x0001) != 0 ||
 461 +                                                   prtspexp->hiport != prtspexp->loport+1) {
 462 +                                                       pr_debug("incorrect range: %hu-%hu, correcting\n",
 463 +                                                              prtspexp->loport, prtspexp->hiport);
 464 +                                                       prtspexp->loport &= 0xfffe;
 465 +                                                       prtspexp->hiport = prtspexp->loport+1;
 466 +                                               }
 467 +                                       } else if (ptran[off] == '/') {
 468 +                                               off++;
 469 +                                               numlen = nf_strtou16(ptran+off, &port);
 470 +                                               off += numlen;
 471 +                                               prtspexp->pbtype = pb_discon;
 472 +                                               prtspexp->hiport = port;
 473 +                                       }
 474 +                                       rc = 1;
 475 +                               }
 476 +                       }
 477 +
 478 +                       /*
 479 +                        * Note we don't look for the destination parameter here.
 480 +                        * If we are using NAT, the NAT module will handle it.  If not,
 481 +                        * and the client is sending packets elsewhere, the expectation
 482 +                        * will quietly time out.
 483 +                        */
 484 +
 485 +                       off = nextfieldoff;
 486 +               }
 487 +
 488 +               off = nextparamoff;
 489 +       }
 490 +
 491 +       return rc;
 492 +}
 493 +
 494 +void expected(struct nf_conn *ct, struct nf_conntrack_expect *exp)
 495 +{
 496 +               typeof(nf_nat_rtsp_hook_expectfn) nf_nat_rtsp_expectfn;
 497 +               nf_nat_rtsp_expectfn = rcu_dereference(nf_nat_rtsp_hook_expectfn);
 498 +    if(nf_nat_rtsp_expectfn && ct->master->status & IPS_NAT_MASK) {
 499 +        nf_nat_rtsp_expectfn(ct,exp);
 500 +    }
 501 +}
 502 +
 503 +/*** conntrack functions ***/
 504 +
 505 +/* outbound packet: client->server */
 506 +
 507 +static inline int
 508 +help_out(struct sk_buff *skb, unsigned char *rb_ptr, unsigned int datalen,
 509 +                struct nf_conn *ct, enum ip_conntrack_info ctinfo)
 510 +{
 511 +       struct ip_ct_rtsp_expect expinfo;
 512 +
 513 +       int dir = CTINFO2DIR(ctinfo);   /* = IP_CT_DIR_ORIGINAL */
 514 +       //struct  tcphdr* tcph = (void*)iph + iph->ihl * 4;
 515 +       //uint    tcplen = pktlen - iph->ihl * 4;
 516 +       char*   pdata = rb_ptr;
 517 +       //uint    datalen = tcplen - tcph->doff * 4;
 518 +       uint    dataoff = 0;
 519 +       int ret = NF_ACCEPT;
 520 +
 521 +       struct nf_conntrack_expect *exp;
 522 +
 523 +       __be16 be_loport;
 524 +
 525 +       typeof(nf_nat_rtsp_hook) nf_nat_rtsp;
 526 +
 527 +       memset(&expinfo, 0, sizeof(expinfo));
 528 +
 529 +       while (dataoff < datalen) {
 530 +               uint    cmdoff = dataoff;
 531 +               uint    hdrsoff = 0;
 532 +               uint    hdrslen = 0;
 533 +               uint    cseqoff = 0;
 534 +               uint    cseqlen = 0;
 535 +               uint    transoff = 0;
 536 +               uint    translen = 0;
 537 +               uint    off;
 538 +
 539 +               if (!rtsp_parse_message(pdata, datalen, &dataoff,
 540 +                                       &hdrsoff, &hdrslen,
 541 +                                       &cseqoff, &cseqlen,
 542 +                                       &transoff, &translen))
 543 +                       break;      /* not a valid message */
 544 +
 545 +               if (strncmp(pdata+cmdoff, "SETUP ", 6) != 0)
 546 +                       continue;   /* not a SETUP message */
 547 +               pr_debug("found a setup message\n");
 548 +
 549 +               off = 0;
 550 +               if(translen) {
 551 +                       rtsp_parse_transport(pdata+transoff, translen, &expinfo);
 552 +               }
 553 +
 554 +               if (expinfo.loport == 0) {
 555 +                       pr_debug("no udp transports found\n");
 556 +                       continue;   /* no udp transports found */
 557 +               }
 558 +
 559 +               pr_debug("udp transport found, ports=(%d,%hu,%hu)\n",
 560 +                      (int)expinfo.pbtype, expinfo.loport, expinfo.hiport);
 561 +
 562 +               exp = nf_ct_expect_alloc(ct);
 563 +               if (!exp) {
 564 +                       ret = NF_DROP;
 565 +                       goto out;
 566 +               }
 567 +
 568 +               be_loport = htons(expinfo.loport);
 569 +
 570 +               nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
 571 +                       &ct->tuplehash[!dir].tuple.src.u3, &ct->tuplehash[!dir].tuple.dst.u3,
 572 +                       IPPROTO_UDP, NULL, &be_loport);
 573 +
 574 +               exp->master = ct;
 575 +
 576 +               exp->expectfn = expected;
 577 +               exp->flags = 0;
 578 +
 579 +               if (expinfo.pbtype == pb_range) {
 580 +                       pr_debug("Changing expectation mask to handle multiple ports\n");
 581 +                       //exp->mask.dst.u.udp.port  = 0xfffe;
 582 +               }
 583 +
 584 +               pr_debug("expect_related %pI4:%u-%pI4:%u\n",
 585 +                      &exp->tuple.src.u3.ip,
 586 +                      ntohs(exp->tuple.src.u.udp.port),
 587 +                      &exp->tuple.dst.u3.ip,
 588 +                      ntohs(exp->tuple.dst.u.udp.port));
 589 +
 590 +               nf_nat_rtsp = rcu_dereference(nf_nat_rtsp_hook);
 591 +               if (nf_nat_rtsp && ct->status & IPS_NAT_MASK)
 592 +                       /* pass the request off to the nat helper */
 593 +                       ret = nf_nat_rtsp(skb, ctinfo, hdrsoff, hdrslen, &expinfo, exp);
 594 +               else if (nf_ct_expect_related(exp) != 0) {
 595 +                       pr_info("nf_conntrack_expect_related failed\n");
 596 +                       ret  = NF_DROP;
 597 +               }
 598 +               nf_ct_expect_put(exp);
 599 +               goto out;
 600 +       }
 601 +out:
 602 +
 603 +       return ret;
 604 +}
 605 +
 606 +
 607 +static inline int
 608 +help_in(struct sk_buff *skb, size_t pktlen,
 609 + struct nf_conn* ct, enum ip_conntrack_info ctinfo)
 610 +{
 611 + return NF_ACCEPT;
 612 +}
 613 +
 614 +static int help(struct sk_buff *skb, unsigned int protoff,
 615 +               struct nf_conn *ct, enum ip_conntrack_info ctinfo)
 616 +{
 617 +       struct tcphdr _tcph, *th;
 618 +       unsigned int dataoff, datalen;
 619 +       char *rb_ptr;
 620 +       int ret = NF_DROP;
 621 +
 622 +       /* Until there's been traffic both ways, don't look in packets. */
 623 +       if (ctinfo != IP_CT_ESTABLISHED &&
 624 +           ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) {
 625 +               pr_debug("conntrackinfo = %u\n", ctinfo);
 626 +               return NF_ACCEPT;
 627 +       }
 628 +
 629 +       /* Not whole TCP header? */
 630 +       th = skb_header_pointer(skb,protoff, sizeof(_tcph), &_tcph);
 631 +
 632 +       if (!th)
 633 +               return NF_ACCEPT;
 634 +
 635 +       /* No data ? */
 636 +       dataoff = protoff + th->doff*4;
 637 +       datalen = skb->len - dataoff;
 638 +       if (dataoff >= skb->len)
 639 +               return NF_ACCEPT;
 640 +
 641 +       spin_lock_bh(&rtsp_buffer_lock);
 642 +       rb_ptr = skb_header_pointer(skb, dataoff,
 643 +                                   skb->len - dataoff, rtsp_buffer);
 644 +       BUG_ON(rb_ptr == NULL);
 645 +
 646 +#if 0
 647 +       /* Checksum invalid?  Ignore. */
 648 +       /* FIXME: Source route IP option packets --RR */
 649 +       if (tcp_v4_check(tcph, tcplen, iph->saddr, iph->daddr,
 650 +                        csum_partial((char*)tcph, tcplen, 0)))
 651 +       {
 652 +               DEBUGP("bad csum: %p %u %u.%u.%u.%u %u.%u.%u.%u\n",
 653 +                      tcph, tcplen, NIPQUAD(iph->saddr), NIPQUAD(iph->daddr));
 654 +               return NF_ACCEPT;
 655 +       }
 656 +#endif
 657 +
 658 +       switch (CTINFO2DIR(ctinfo)) {
 659 +       case IP_CT_DIR_ORIGINAL:
 660 +               ret = help_out(skb, rb_ptr, datalen, ct, ctinfo);
 661 +               break;
 662 +       case IP_CT_DIR_REPLY:
 663 +               pr_debug("IP_CT_DIR_REPLY\n");
 664 +               /* inbound packet: server->client */
 665 +               ret = NF_ACCEPT;
 666 +               break;
 667 +       }
 668 +
 669 +       spin_unlock_bh(&rtsp_buffer_lock);
 670 +
 671 +       return ret;
 672 +}
 673 +
 674 +static struct nf_conntrack_helper rtsp_helpers[MAX_PORTS];
 675 +static char rtsp_names[MAX_PORTS][10];
 676 +
 677 +/* This function is intentionally _NOT_ defined as __exit */
 678 +static void
 679 +fini(void)
 680 +{
 681 +       int i;
 682 +       for (i = 0; i < num_ports; i++) {
 683 +               pr_debug("unregistering port %d\n", ports[i]);
 684 +               nf_conntrack_helper_unregister(&rtsp_helpers[i]);
 685 +       }
 686 +       kfree(rtsp_buffer);
 687 +}
 688 +
 689 +static int __init
 690 +init(void)
 691 +{
 692 +       int i, ret;
 693 +       struct nf_conntrack_helper *hlpr;
 694 +       char *tmpname;
 695 +
 696 +       printk("nf_conntrack_rtsp v" IP_NF_RTSP_VERSION " loading\n");
 697 +
 698 +       if (max_outstanding < 1) {
 699 +               printk("nf_conntrack_rtsp: max_outstanding must be a positive integer\n");
 700 +               return -EBUSY;
 701 +       }
 702 +       if (setup_timeout < 0) {
 703 +               printk("nf_conntrack_rtsp: setup_timeout must be a positive integer\n");
 704 +               return -EBUSY;
 705 +       }
 706 +
 707 +  rtsp_exp_policy.max_expected = max_outstanding;
 708 +  rtsp_exp_policy.timeout = setup_timeout;
 709 +
 710 +       rtsp_buffer = kmalloc(65536, GFP_KERNEL);
 711 +       if (!rtsp_buffer)
 712 +               return -ENOMEM;
 713 +
 714 +       /* If no port given, default to standard rtsp port */
 715 +       if (ports[0] == 0) {
 716 +               ports[0] = RTSP_PORT;
 717 +       }
 718 +
 719 +       for (i = 0; (i < MAX_PORTS) && ports[i]; i++) {
 720 +               hlpr = &rtsp_helpers[i];
 721 +               memset(hlpr, 0, sizeof(struct nf_conntrack_helper));
 722 +               hlpr->tuple.src.l3num = AF_INET;
 723 +               hlpr->tuple.src.u.tcp.port = htons(ports[i]);
 724 +               hlpr->tuple.dst.protonum = IPPROTO_TCP;
 725 +               //hlpr->mask.src.u.tcp.port = 0xFFFF;
 726 +               //hlpr->mask.dst.protonum = 0xFF;
 727 +               hlpr->expect_policy = &rtsp_exp_policy;
 728 +               hlpr->me = THIS_MODULE;
 729 +               hlpr->help = help;
 730 +
 731 +               tmpname = &rtsp_names[i][0];
 732 +               if (ports[i] == RTSP_PORT) {
 733 +                       sprintf(tmpname, "rtsp");
 734 +               } else {
 735 +                       sprintf(tmpname, "rtsp-%d", i);
 736 +               }
 737 +               hlpr->name = tmpname;
 738 +
 739 +               pr_debug("port #%d: %d\n", i, ports[i]);
 740 +
 741 +               ret = nf_conntrack_helper_register(hlpr);
 742 +
 743 +               if (ret) {
 744 +                       printk("nf_conntrack_rtsp: ERROR registering port %d\n", ports[i]);
 745 +                       fini();
 746 +                       return -EBUSY;
 747 +               }
 748 +               num_ports++;
 749 +       }
 750 +       return 0;
 751 +}
 752 +
 753 +module_init(init);
 754 +module_exit(fini);
 755 +
 756 +EXPORT_SYMBOL(nf_nat_rtsp_hook_expectfn);
 757 +
 758 --- /dev/null
 759 +++ b/extensions/rtsp/nf_conntrack_rtsp.h
 760 @@ -0,0 +1,63 @@
 761 +/*
 762 + * RTSP extension for IP connection tracking.
 763 + * (C) 2003 by Tom Marshall <tmarshall at real.com>
 764 + * based on ip_conntrack_irc.h
 765 + *
 766 + *      This program is free software; you can redistribute it and/or
 767 + *      modify it under the terms of the GNU General Public License
 768 + *      as published by the Free Software Foundation; either version
 769 + *      2 of the License, or (at your option) any later version.
 770 + */
 771 +#ifndef _IP_CONNTRACK_RTSP_H
 772 +#define _IP_CONNTRACK_RTSP_H
 773 +
 774 +//#define IP_NF_RTSP_DEBUG 1
 775 +#define IP_NF_RTSP_VERSION "0.6.21"
 776 +
 777 +#ifdef __KERNEL__
 778 +/* port block types */
 779 +typedef enum {
 780 +    pb_single,  /* client_port=x */
 781 +    pb_range,   /* client_port=x-y */
 782 +    pb_discon   /* client_port=x/y (rtspbis) */
 783 +} portblock_t;
 784 +
 785 +/* We record seq number and length of rtsp headers here, all in host order. */
 786 +
 787 +/*
 788 + * This structure is per expected connection.  It is a member of struct
 789 + * ip_conntrack_expect.  The TCP SEQ for the conntrack expect is stored
 790 + * there and we are expected to only store the length of the data which
 791 + * needs replaced.  If a packet contains multiple RTSP messages, we create
 792 + * one expected connection per message.
 793 + *
 794 + * We use these variables to mark the entire header block.  This may seem
 795 + * like overkill, but the nature of RTSP requires it.  A header may appear
 796 + * multiple times in a message.  We must treat two Transport headers the
 797 + * same as one Transport header with two entries.
 798 + */
 799 +struct ip_ct_rtsp_expect
 800 +{
 801 +    u_int32_t   len;        /* length of header block */
 802 +    portblock_t pbtype;     /* Type of port block that was requested */
 803 +    u_int16_t   loport;     /* Port that was requested, low or first */
 804 +    u_int16_t   hiport;     /* Port that was requested, high or second */
 805 +#if 0
 806 +    uint        method;     /* RTSP method */
 807 +    uint        cseq;       /* CSeq from request */
 808 +#endif
 809 +};
 810 +
 811 +extern unsigned int (*nf_nat_rtsp_hook)(struct sk_buff *skb,
 812 +                                enum ip_conntrack_info ctinfo,
 813 +                                unsigned int matchoff, unsigned int matchlen,
 814 +                                struct ip_ct_rtsp_expect *prtspexp,
 815 +                                struct nf_conntrack_expect *exp);
 816 +
 817 +extern void (*nf_nat_rtsp_hook_expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp);
 818 +
 819 +#define RTSP_PORT   554
 820 +
 821 +#endif /* __KERNEL__ */
 822 +
 823 +#endif /* _IP_CONNTRACK_RTSP_H */
 824 --- /dev/null
 825 +++ b/extensions/rtsp/nf_nat_rtsp.c
 826 @@ -0,0 +1,491 @@
 827 +/*
 828 + * RTSP extension for TCP NAT alteration
 829 + * (C) 2003 by Tom Marshall <tmarshall at real.com>
 830 + * based on ip_nat_irc.c
 831 + *
 832 + *      This program is free software; you can redistribute it and/or
 833 + *      modify it under the terms of the GNU General Public License
 834 + *      as published by the Free Software Foundation; either version
 835 + *      2 of the License, or (at your option) any later version.
 836 + *
 837 + * Module load syntax:
 838 + *      insmod nf_nat_rtsp.o ports=port1,port2,...port<MAX_PORTS>
 839 + *                           stunaddr=<address>
 840 + *                           destaction=[auto|strip|none]
 841 + *
 842 + * If no ports are specified, the default will be port 554 only.
 843 + *
 844 + * stunaddr specifies the address used to detect that a client is using STUN.
 845 + * If this address is seen in the destination parameter, it is assumed that
 846 + * the client has already punched a UDP hole in the firewall, so we don't
 847 + * mangle the client_port.  If none is specified, it is autodetected.  It
 848 + * only needs to be set if you have multiple levels of NAT.  It should be
 849 + * set to the external address that the STUN clients detect.  Note that in
 850 + * this case, it will not be possible for clients to use UDP with servers
 851 + * between the NATs.
 852 + *
 853 + * If no destaction is specified, auto is used.
 854 + *   destaction=auto:  strip destination parameter if it is not stunaddr.
 855 + *   destaction=strip: always strip destination parameter (not recommended).
 856 + *   destaction=none:  do not touch destination parameter (not recommended).
 857 + */
 858 +
 859 +#include <linux/module.h>
 860 +#include <net/tcp.h>
 861 +#include <net/netfilter/nf_nat_helper.h>
 862 +#include <net/netfilter/nf_nat_rule.h>
 863 +#include "nf_conntrack_rtsp.h"
 864 +#include <net/netfilter/nf_conntrack_expect.h>
 865 +
 866 +#include <linux/inet.h>
 867 +#include <linux/ctype.h>
 868 +#define NF_NEED_STRNCASECMP
 869 +#define NF_NEED_STRTOU16
 870 +#include "netfilter_helpers.h"
 871 +#define NF_NEED_MIME_NEXTLINE
 872 +#include "netfilter_mime.h"
 873 +
 874 +#include "../compat_xtables.h"
 875 +
 876 +#define MAX_PORTS       8
 877 +#define DSTACT_AUTO     0
 878 +#define DSTACT_STRIP    1
 879 +#define DSTACT_NONE     2
 880 +
 881 +static char*    stunaddr = NULL;
 882 +static char*    destaction = NULL;
 883 +
 884 +static u_int32_t extip = 0;
 885 +static int       dstact = 0;
 886 +
 887 +MODULE_AUTHOR("Tom Marshall <tmarshall at real.com>");
 888 +MODULE_DESCRIPTION("RTSP network address translation module");
 889 +MODULE_LICENSE("GPL");
 890 +module_param(stunaddr, charp, 0644);
 891 +MODULE_PARM_DESC(stunaddr, "Address for detecting STUN");
 892 +module_param(destaction, charp, 0644);
 893 +MODULE_PARM_DESC(destaction, "Action for destination parameter (auto/strip/none)");
 894 +
 895 +#define SKIP_WSPACE(ptr,len,off) while(off < len && isspace(*(ptr+off))) { off++; }
 896 +
 897 +/*** helper functions ***/
 898 +
 899 +static void
 900 +get_skb_tcpdata(struct sk_buff* skb, char** pptcpdata, uint* ptcpdatalen)
 901 +{
 902 +    struct iphdr*   iph  = ip_hdr(skb);
 903 +    struct tcphdr*  tcph = (void *)iph + ip_hdrlen(skb);
 904 +
 905 +    *pptcpdata = (char*)tcph +  tcph->doff*4;
 906 +    *ptcpdatalen = ((char*)skb_transport_header(skb) + skb->len) - *pptcpdata;
 907 +}
 908 +
 909 +/*** nat functions ***/
 910 +
 911 +/*
 912 + * Mangle the "Transport:" header:
 913 + *   - Replace all occurences of "client_port=<spec>"
 914 + *   - Handle destination parameter
 915 + *
 916 + * In:
 917 + *   ct, ctinfo = conntrack context
 918 + *   skb        = packet
 919 + *   tranoff    = Transport header offset from TCP data
 920 + *   tranlen    = Transport header length (incl. CRLF)
 921 + *   rport_lo   = replacement low  port (host endian)
 922 + *   rport_hi   = replacement high port (host endian)
 923 + *
 924 + * Returns packet size difference.
 925 + *
 926 + * Assumes that a complete transport header is present, ending with CR or LF
 927 + */
 928 +static int
 929 +rtsp_mangle_tran(enum ip_conntrack_info ctinfo,
 930 +                 struct nf_conntrack_expect* exp,
 931 +                                                                struct ip_ct_rtsp_expect* prtspexp,
 932 +                 struct sk_buff* skb, uint tranoff, uint tranlen)
 933 +{
 934 +    char*       ptcp;
 935 +    uint        tcplen;
 936 +    char*       ptran;
 937 +    char        rbuf1[16];      /* Replacement buffer (one port) */
 938 +    uint        rbuf1len;       /* Replacement len (one port) */
 939 +    char        rbufa[16];      /* Replacement buffer (all ports) */
 940 +    uint        rbufalen;       /* Replacement len (all ports) */
 941 +    u_int32_t   newip;
 942 +    u_int16_t   loport, hiport;
 943 +    uint        off = 0;
 944 +    uint        diff;           /* Number of bytes we removed */
 945 +
 946 +    struct nf_conn *ct = exp->master;
 947 +    struct nf_conntrack_tuple *t;
 948 +
 949 +    char    szextaddr[15+1];
 950 +    uint    extaddrlen;
 951 +    int     is_stun;
 952 +
 953 +    get_skb_tcpdata(skb, &ptcp, &tcplen);
 954 +    ptran = ptcp+tranoff;
 955 +
 956 +    if (tranoff+tranlen > tcplen || tcplen-tranoff < tranlen ||
 957 +        tranlen < 10 || !iseol(ptran[tranlen-1]) ||
 958 +        nf_strncasecmp(ptran, "Transport:", 10) != 0)
 959 +    {
 960 +        pr_info("sanity check failed\n");
 961 +        return 0;
 962 +    }
 963 +    off += 10;
 964 +    SKIP_WSPACE(ptcp+tranoff, tranlen, off);
 965 +
 966 +    newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip;
 967 +    t = &exp->tuple;
 968 +    t->dst.u3.ip = newip;
 969 +
 970 +    extaddrlen = extip ? sprintf(szextaddr, "%pI4", &extip)
 971 +                       : sprintf(szextaddr, "%pI4", &newip);
 972 +    pr_debug("stunaddr=%s (%s)\n", szextaddr, (extip?"forced":"auto"));
 973 +
 974 +    rbuf1len = rbufalen = 0;
 975 +    switch (prtspexp->pbtype)
 976 +    {
 977 +    case pb_single:
 978 +        for (loport = prtspexp->loport; loport != 0; loport++) /* XXX: improper wrap? */
 979 +        {
 980 +            t->dst.u.udp.port = htons(loport);
 981 +            if (nf_ct_expect_related(exp) == 0)
 982 +            {
 983 +                pr_debug("using port %hu\n", loport);
 984 +                break;
 985 +            }
 986 +        }
 987 +        if (loport != 0)
 988 +        {
 989 +            rbuf1len = sprintf(rbuf1, "%hu", loport);
 990 +            rbufalen = sprintf(rbufa, "%hu", loport);
 991 +        }
 992 +        break;
 993 +    case pb_range:
 994 +        for (loport = prtspexp->loport; loport != 0; loport += 2) /* XXX: improper wrap? */
 995 +        {
 996 +            t->dst.u.udp.port = htons(loport);
 997 +            if (nf_ct_expect_related(exp) == 0)
 998 +            {
 999 +                hiport = loport + 1; //~exp->mask.dst.u.udp.port;
1000 +                pr_debug("using ports %hu-%hu\n", loport, hiport);
1001 +                break;
1002 +            }
1003 +        }
1004 +        if (loport != 0)
1005 +        {
1006 +            rbuf1len = sprintf(rbuf1, "%hu", loport);
1007 +            rbufalen = sprintf(rbufa, "%hu-%hu", loport, loport+1);
1008 +        }
1009 +        break;
1010 +    case pb_discon:
1011 +        for (loport = prtspexp->loport; loport != 0; loport++) /* XXX: improper wrap? */
1012 +        {
1013 +            t->dst.u.udp.port = htons(loport);
1014 +            if (nf_ct_expect_related(exp) == 0)
1015 +            {
1016 +                pr_debug("using port %hu (1 of 2)\n", loport);
1017 +                break;
1018 +            }
1019 +        }
1020 +        for (hiport = prtspexp->hiport; hiport != 0; hiport++) /* XXX: improper wrap? */
1021 +        {
1022 +            t->dst.u.udp.port = htons(hiport);
1023 +            if (nf_ct_expect_related(exp) == 0)
1024 +            {
1025 +                pr_debug("using port %hu (2 of 2)\n", hiport);
1026 +                break;
1027 +            }
1028 +        }
1029 +        if (loport != 0 && hiport != 0)
1030 +        {
1031 +            rbuf1len = sprintf(rbuf1, "%hu", loport);
1032 +            if (hiport == loport+1)
1033 +            {
1034 +                rbufalen = sprintf(rbufa, "%hu-%hu", loport, hiport);
1035 +            }
1036 +            else
1037 +            {
1038 +                rbufalen = sprintf(rbufa, "%hu/%hu", loport, hiport);
1039 +            }
1040 +        }
1041 +        break;
1042 +    }
1043 +
1044 +    if (rbuf1len == 0)
1045 +    {
1046 +        return 0;   /* cannot get replacement port(s) */
1047 +    }
1048 +
1049 +    /* Transport: tran;field;field=val,tran;field;field=val,... */
1050 +    while (off < tranlen)
1051 +    {
1052 +        uint        saveoff;
1053 +        const char* pparamend;
1054 +        uint        nextparamoff;
1055 +
1056 +        pparamend = memchr(ptran+off, ',', tranlen-off);
1057 +        pparamend = (pparamend == NULL) ? ptran+tranlen : pparamend+1;
1058 +        nextparamoff = pparamend-ptcp;
1059 +
1060 +        /*
1061 +         * We pass over each param twice.  On the first pass, we look for a
1062 +         * destination= field.  It is handled by the security policy.  If it
1063 +         * is present, allowed, and equal to our external address, we assume
1064 +         * that STUN is being used and we leave the client_port= field alone.
1065 +         */
1066 +        is_stun = 0;
1067 +        saveoff = off;
1068 +        while (off < nextparamoff)
1069 +        {
1070 +            const char* pfieldend;
1071 +            uint        nextfieldoff;
1072 +
1073 +            pfieldend = memchr(ptran+off, ';', nextparamoff-off);
1074 +            nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
1075 +
1076 +            if (dstact != DSTACT_NONE && strncmp(ptran+off, "destination=", 12) == 0)
1077 +            {
1078 +                if (strncmp(ptran+off+12, szextaddr, extaddrlen) == 0)
1079 +                {
1080 +                    is_stun = 1;
1081 +                }
1082 +                if (dstact == DSTACT_STRIP || (dstact == DSTACT_AUTO && !is_stun))
1083 +                {
1084 +                    diff = nextfieldoff-off;
1085 +                    if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
1086 +                                                         off, diff, NULL, 0))
1087 +                    {
1088 +                        /* mangle failed, all we can do is bail */
1089 +                       nf_ct_unexpect_related(exp);
1090 +                        return 0;
1091 +                    }
1092 +                    get_skb_tcpdata(skb, &ptcp, &tcplen);
1093 +                    ptran = ptcp+tranoff;
1094 +                    tranlen -= diff;
1095 +                    nextparamoff -= diff;
1096 +                    nextfieldoff -= diff;
1097 +                }
1098 +            }
1099 +
1100 +            off = nextfieldoff;
1101 +        }
1102 +        if (is_stun)
1103 +        {
1104 +            continue;
1105 +        }
1106 +        off = saveoff;
1107 +        while (off < nextparamoff)
1108 +        {
1109 +            const char* pfieldend;
1110 +            uint        nextfieldoff;
1111 +
1112 +            pfieldend = memchr(ptran+off, ';', nextparamoff-off);
1113 +            nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
1114 +
1115 +            if (strncmp(ptran+off, "client_port=", 12) == 0)
1116 +            {
1117 +                u_int16_t   port;
1118 +                uint        numlen;
1119 +                uint        origoff;
1120 +                uint        origlen;
1121 +                char*       rbuf    = rbuf1;
1122 +                uint        rbuflen = rbuf1len;
1123 +
1124 +                off += 12;
1125 +                origoff = (ptran-ptcp)+off;
1126 +                origlen = 0;
1127 +                numlen = nf_strtou16(ptran+off, &port);
1128 +                off += numlen;
1129 +                origlen += numlen;
1130 +                if (port != prtspexp->loport)
1131 +                {
1132 +                    pr_debug("multiple ports found, port %hu ignored\n", port);
1133 +                }
1134 +                else
1135 +                {
1136 +                    if (ptran[off] == '-' || ptran[off] == '/')
1137 +                    {
1138 +                        off++;
1139 +                        origlen++;
1140 +                        numlen = nf_strtou16(ptran+off, &port);
1141 +                        off += numlen;
1142 +                        origlen += numlen;
1143 +                        rbuf = rbufa;
1144 +                        rbuflen = rbufalen;
1145 +                    }
1146 +
1147 +                    /*
1148 +                     * note we cannot just memcpy() if the sizes are the same.
1149 +                     * the mangle function does skb resizing, checks for a
1150 +                     * cloned skb, and updates the checksums.
1151 +                     *
1152 +                     * parameter 4 below is offset from start of tcp data.
1153 +                     */
1154 +                    diff = origlen-rbuflen;
1155 +                    if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
1156 +                                              origoff, origlen, rbuf, rbuflen))
1157 +                    {
1158 +                        /* mangle failed, all we can do is bail */
1159 +                       nf_ct_unexpect_related(exp);
1160 +                        return 0;
1161 +                    }
1162 +                    get_skb_tcpdata(skb, &ptcp, &tcplen);
1163 +                    ptran = ptcp+tranoff;
1164 +                    tranlen -= diff;
1165 +                    nextparamoff -= diff;
1166 +                    nextfieldoff -= diff;
1167 +                }
1168 +            }
1169 +
1170 +            off = nextfieldoff;
1171 +        }
1172 +
1173 +        off = nextparamoff;
1174 +    }
1175 +
1176 +    return 1;
1177 +}
1178 +
1179 +static uint
1180 +help_out(struct sk_buff *skb, enum ip_conntrack_info ctinfo,
1181 +        unsigned int matchoff, unsigned int matchlen, struct ip_ct_rtsp_expect* prtspexp,
1182 +        struct nf_conntrack_expect* exp)
1183 +{
1184 +    char*   ptcp;
1185 +    uint    tcplen;
1186 +    uint    hdrsoff;
1187 +    uint    hdrslen;
1188 +    uint    lineoff;
1189 +    uint    linelen;
1190 +    uint    off;
1191 +
1192 +    //struct iphdr* iph = (struct iphdr*)(*pskb)->nh.iph;
1193 +    //struct tcphdr* tcph = (struct tcphdr*)((void*)iph + iph->ihl*4);
1194 +
1195 +    get_skb_tcpdata(skb, &ptcp, &tcplen);
1196 +    hdrsoff = matchoff;//exp->seq - ntohl(tcph->seq);
1197 +    hdrslen = matchlen;
1198 +    off = hdrsoff;
1199 +    pr_debug("NAT rtsp help_out\n");
1200 +
1201 +    while (nf_mime_nextline(ptcp, hdrsoff+hdrslen, &off, &lineoff, &linelen))
1202 +    {
1203 +        if (linelen == 0)
1204 +        {
1205 +            break;
1206 +        }
1207 +        if (off > hdrsoff+hdrslen)
1208 +        {
1209 +            pr_info("!! overrun !!");
1210 +            break;
1211 +        }
1212 +        pr_debug("hdr: len=%u, %.*s", linelen, (int)linelen, ptcp+lineoff);
1213 +
1214 +        if (nf_strncasecmp(ptcp+lineoff, "Transport:", 10) == 0)
1215 +        {
1216 +            uint oldtcplen = tcplen;
1217 +           pr_debug("hdr: Transport\n");
1218 +            if (!rtsp_mangle_tran(ctinfo, exp, prtspexp, skb, lineoff, linelen))
1219 +            {
1220 +               pr_debug("hdr: Transport mangle failed");
1221 +                break;
1222 +            }
1223 +            get_skb_tcpdata(skb, &ptcp, &tcplen);
1224 +            hdrslen -= (oldtcplen-tcplen);
1225 +            off -= (oldtcplen-tcplen);
1226 +            lineoff -= (oldtcplen-tcplen);
1227 +            linelen -= (oldtcplen-tcplen);
1228 +            pr_debug("rep: len=%u, %.*s", linelen, (int)linelen, ptcp+lineoff);
1229 +        }
1230 +    }
1231 +
1232 +    return NF_ACCEPT;
1233 +}
1234 +
1235 +static unsigned int
1236 +help(struct sk_buff *skb, enum ip_conntrack_info ctinfo,
1237 +     unsigned int matchoff, unsigned int matchlen, struct ip_ct_rtsp_expect* prtspexp,
1238 +     struct nf_conntrack_expect* exp)
1239 +{
1240 +    int dir = CTINFO2DIR(ctinfo);
1241 +    int rc = NF_ACCEPT;
1242 +
1243 +    switch (dir)
1244 +    {
1245 +    case IP_CT_DIR_ORIGINAL:
1246 +        rc = help_out(skb, ctinfo, matchoff, matchlen, prtspexp, exp);
1247 +        break;
1248 +    case IP_CT_DIR_REPLY:
1249 +       pr_debug("unmangle ! %u\n", ctinfo);
1250 +       /* XXX: unmangle */
1251 +       rc = NF_ACCEPT;
1252 +        break;
1253 +    }
1254 +    //UNLOCK_BH(&ip_rtsp_lock);
1255 +
1256 +    return rc;
1257 +}
1258 +
1259 +static void expected(struct nf_conn* ct, struct nf_conntrack_expect *exp)
1260 +{
1261 +    struct nf_nat_ipv4_multi_range_compat mr;
1262 +    u_int32_t newdstip, newsrcip, newip;
1263 +
1264 +    struct nf_conn *master = ct->master;
1265 +
1266 +    newdstip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
1267 +    newsrcip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
1268 +    //FIXME (how to port that ?)
1269 +    //code from 2.4 : newip = (HOOK2MANIP(hooknum) == NF_NAT_MANIP_SRC) ? newsrcip : newdstip;
1270 +    newip = newdstip;
1271 +
1272 +    pr_debug("newsrcip=%pI4, newdstip=%pI4, newip=%pI4\n",
1273 +           &newsrcip, &newdstip, &newip);
1274 +
1275 +    mr.rangesize = 1;
1276 +    // We don't want to manip the per-protocol, just the IPs.
1277 +    mr.range[0].flags = NF_NAT_RANGE_MAP_IPS;
1278 +    mr.range[0].min_ip = mr.range[0].max_ip = newip;
1279 +
1280 +    nf_nat_setup_info(ct, &mr.range[0], NF_NAT_MANIP_DST);
1281 +}
1282 +
1283 +
1284 +static void __exit fini(void)
1285 +{
1286 +       nf_nat_rtsp_hook = NULL;
1287 +        nf_nat_rtsp_hook_expectfn = NULL;
1288 +       synchronize_net();
1289 +}
1290 +
1291 +static int __init init(void)
1292 +{
1293 +       printk("nf_nat_rtsp v" IP_NF_RTSP_VERSION " loading\n");
1294 +
1295 +       BUG_ON(nf_nat_rtsp_hook);
1296 +       nf_nat_rtsp_hook = help;
1297 +        nf_nat_rtsp_hook_expectfn = &expected;
1298 +
1299 +       if (stunaddr != NULL)
1300 +               extip = in_aton(stunaddr);
1301 +
1302 +       if (destaction != NULL) {
1303 +               if (strcmp(destaction, "auto") == 0)
1304 +                       dstact = DSTACT_AUTO;
1305 +
1306 +               if (strcmp(destaction, "strip") == 0)
1307 +                       dstact = DSTACT_STRIP;
1308 +
1309 +               if (strcmp(destaction, "none") == 0)
1310 +                       dstact = DSTACT_NONE;
1311 +       }
1312 +
1313 +       return 0;
1314 +}
1315 +
1316 +module_init(init);
1317 +module_exit(fini);
1318 --- a/extensions/Kbuild
1319 +++ b/extensions/Kbuild
1320 @@ -28,6 +28,7 @@ obj-${build_lscan}       += xt_lscan.o
1321  obj-${build_pknock}      += pknock/
1322  obj-${build_psd}         += xt_psd.o
1323  obj-${build_quota2}      += xt_quota2.o
1324 +obj-${build_rtsp}        += rtsp/
1325
1326  -include ${M}/*.Kbuild
1327  -include ${M}/Kbuild.*
1328 --- a/mconfig
1329 +++ b/mconfig
1330 @@ -22,3 +22,4 @@ build_lscan=m
1331  build_pknock=m
1332  build_psd=m
1333  build_quota2=m
1334 +build_rtsp=m