target/linux/generic-2.6/patches-2.6.28/190-netfilter_rtsp.patch

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