target/linux/generic-2.4/patches/615-netfilter_nat_mms.patch

   1 --- a/net/ipv4/netfilter/Config.in
   2 +++ b/net/ipv4/netfilter/Config.in
   3 @@ -15,6 +15,7 @@ if [ "$CONFIG_IP_NF_CONNTRACK" != "n" ];
   4    dep_tristate '  Connection byte counter support' CONFIG_IP_NF_MATCH_CONNBYTES $CONFIG_IP_NF_CT_ACCT $CONFIG_IP_NF_CONNTRACK $CONFIG_IP_NF_IPTABLES
   5    dep_tristate '  H.323 (netmeeting) support' CONFIG_IP_NF_H323 $CONFIG_IP_NF_CONNTRACK
   6    dep_tristate '  RTSP protocol support' CONFIG_IP_NF_RTSP $CONFIG_IP_NF_CONNTRACK
   7 +  dep_tristate '  MMS protocol support' CONFIG_IP_NF_MMS $CONFIG_IP_NF_CONNTRACK
   8  fi
   9
  10  if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then
  11 @@ -96,6 +97,13 @@ if [ "$CONFIG_IP_NF_IPTABLES" != "n" ];
  12           define_tristate CONFIG_IP_NF_NAT_RTSP $CONFIG_IP_NF_NAT
  13         fi
  14        fi
  15 +      if [ "$CONFIG_IP_NF_MMS" = "m" ]; then
  16 +       define_tristate CONFIG_IP_NF_NAT_MMS m
  17 +      else
  18 +       if [ "$CONFIG_IP_NF_MMS" = "y" ]; then
  19 +         define_tristate CONFIG_IP_NF_NAT_MMS $CONFIG_IP_NF_NAT
  20 +       fi
  21 +      fi
  22        if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then
  23          dep_tristate '    Basic SNMP-ALG support (EXPERIMENTAL)' CONFIG_IP_NF_NAT_SNMP_BASIC $CONFIG_IP_NF_NAT
  24        fi
  25 --- a/net/ipv4/netfilter/Makefile
  26 +++ b/net/ipv4/netfilter/Makefile
  27 @@ -55,6 +55,10 @@ obj-$(CONFIG_IP_NF_RTSP) += ip_conntrack
  28  ifdef CONFIG_IP_NF_NAT_RTSP
  29         export-objs += ip_conntrack_rtsp.o
  30  endif
  31 +obj-$(CONFIG_IP_NF_MMS) += ip_conntrack_mms.o
  32 +ifdef CONFIG_IP_NF_NAT_MMS
  33 +       export-objs += ip_conntrack_mms.o
  34 +endif
  35
  36
  37  # NAT helpers
  38 @@ -64,6 +68,7 @@ obj-$(CONFIG_IP_NF_NAT_FTP) += ip_nat_ft
  39  obj-$(CONFIG_IP_NF_NAT_IRC) += ip_nat_irc.o
  40  obj-$(CONFIG_IP_NF_NAT_H323) += ip_nat_h323.o
  41  obj-$(CONFIG_IP_NF_NAT_RTSP) += ip_nat_rtsp.o
  42 +obj-$(CONFIG_IP_NF_NAT_MMS) += ip_nat_mms.o
  43
  44  # generic IP tables
  45  obj-$(CONFIG_IP_NF_IPTABLES) += ip_tables.o
  46 --- /dev/null
  47 +++ b/net/ipv4/netfilter/ip_conntrack_mms.c
  48 @@ -0,0 +1,292 @@
  49 +/* MMS extension for IP connection tracking
  50 + * (C) 2002 by Filip Sneppe <filip.sneppe@cronos.be>
  51 + * based on ip_conntrack_ftp.c and ip_conntrack_irc.c
  52 + *
  53 + * ip_conntrack_mms.c v0.3 2002-09-22
  54 + *
  55 + *      This program is free software; you can redistribute it and/or
  56 + *      modify it under the terms of the GNU General Public License
  57 + *      as published by the Free Software Foundation; either version
  58 + *      2 of the License, or (at your option) any later version.
  59 + *
  60 + *      Module load syntax:
  61 + *      insmod ip_conntrack_mms.o ports=port1,port2,...port<MAX_PORTS>
  62 + *
  63 + *      Please give the ports of all MMS servers You wish to connect to.
  64 + *      If you don't specify ports, the default will be TCP port 1755.
  65 + *
  66 + *      More info on MMS protocol, firewalls and NAT:
  67 + *      http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnwmt/html/MMSFirewall.asp
  68 + *      http://www.microsoft.com/windows/windowsmedia/serve/firewall.asp
  69 + *
  70 + *      The SDP project people are reverse-engineering MMS:
  71 + *      http://get.to/sdp
  72 + */
  73 +
  74 +#include <linux/config.h>
  75 +#include <linux/module.h>
  76 +#include <linux/netfilter.h>
  77 +#include <linux/ip.h>
  78 +#include <linux/ctype.h>
  79 +#include <net/checksum.h>
  80 +#include <net/tcp.h>
  81 +
  82 +#include <linux/netfilter_ipv4/lockhelp.h>
  83 +#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
  84 +#include <linux/netfilter_ipv4/ip_conntrack_mms.h>
  85 +
  86 +DECLARE_LOCK(ip_mms_lock);
  87 +struct module *ip_conntrack_mms = THIS_MODULE;
  88 +
  89 +#define MAX_PORTS 8
  90 +static int ports[MAX_PORTS];
  91 +static int ports_c;
  92 +#ifdef MODULE_PARM
  93 +MODULE_PARM(ports, "1-" __MODULE_STRING(MAX_PORTS) "i");
  94 +#endif
  95 +
  96 +#define DEBUGP(format, args...)
  97 +
  98 +#ifdef CONFIG_IP_NF_NAT_NEEDED
  99 +EXPORT_SYMBOL(ip_mms_lock);
 100 +#endif
 101 +
 102 +MODULE_AUTHOR("Filip Sneppe <filip.sneppe@cronos.be>");
 103 +MODULE_DESCRIPTION("Microsoft Windows Media Services (MMS) connection tracking module");
 104 +MODULE_LICENSE("GPL");
 105 +
 106 +/* #define isdigit(c) (c >= '0' && c <= '9') */
 107 +
 108 +/* copied from drivers/usb/serial/io_edgeport.c - not perfect but will do the trick */
 109 +static void unicode_to_ascii (char *string, short *unicode, int unicode_size)
 110 +{
 111 +       int i;
 112 +       for (i = 0; i < unicode_size; ++i) {
 113 +               string[i] = (char)(unicode[i]);
 114 +       }
 115 +       string[unicode_size] = 0x00;
 116 +}
 117 +
 118 +__inline static int atoi(char *s)
 119 +{
 120 +       int i=0;
 121 +       while (isdigit(*s)) {
 122 +               i = i*10 + *(s++) - '0';
 123 +       }
 124 +       return i;
 125 +}
 126 +
 127 +/* convert ip address string like "192.168.0.10" to unsigned int */
 128 +__inline static u_int32_t asciiiptoi(char *s)
 129 +{
 130 +       unsigned int i, j, k;
 131 +
 132 +       for(i=k=0; k<3; ++k, ++s, i<<=8) {
 133 +               i+=atoi(s);
 134 +               for(j=0; (*(++s) != '.') && (j<3); ++j)
 135 +                       ;
 136 +       }
 137 +       i+=atoi(s);
 138 +       return ntohl(i);
 139 +}
 140 +
 141 +int parse_mms(const char *data,
 142 +             const unsigned int datalen,
 143 +             u_int32_t *mms_ip,
 144 +             u_int16_t *mms_proto,
 145 +             u_int16_t *mms_port,
 146 +             char **mms_string_b,
 147 +             char **mms_string_e,
 148 +             char **mms_padding_e)
 149 +{
 150 +       int unicode_size, i;
 151 +       char tempstring[28];       /* "\\255.255.255.255\UDP\65535" */
 152 +       char getlengthstring[28];
 153 +
 154 +       for(unicode_size=0;
 155 +           (char) *(data+(MMS_SRV_UNICODE_STRING_OFFSET+unicode_size*2)) != (char)0;
 156 +           unicode_size++)
 157 +               if ((unicode_size == 28) || (MMS_SRV_UNICODE_STRING_OFFSET+unicode_size*2 >= datalen))
 158 +                       return -1; /* out of bounds - incomplete packet */
 159 +
 160 +       unicode_to_ascii(tempstring, (short *)(data+MMS_SRV_UNICODE_STRING_OFFSET), unicode_size);
 161 +       DEBUGP("ip_conntrack_mms: offset 60: %s\n", (const char *)(tempstring));
 162 +
 163 +       /* IP address ? */
 164 +       *mms_ip = asciiiptoi(tempstring+2);
 165 +
 166 +       i=sprintf(getlengthstring, "%u.%u.%u.%u", HIPQUAD(*mms_ip));
 167 +
 168 +       /* protocol ? */
 169 +       if(strncmp(tempstring+3+i, "TCP", 3)==0)
 170 +               *mms_proto = IPPROTO_TCP;
 171 +       else if(strncmp(tempstring+3+i, "UDP", 3)==0)
 172 +               *mms_proto = IPPROTO_UDP;
 173 +
 174 +       /* port ? */
 175 +       *mms_port = atoi(tempstring+7+i);
 176 +
 177 +       /* we store a pointer to the beginning of the "\\a.b.c.d\proto\port"
 178 +          unicode string, one to the end of the string, and one to the end
 179 +          of the packet, since we must keep track of the number of bytes
 180 +          between end of the unicode string and the end of packet (padding) */
 181 +       *mms_string_b  = (char *)(data + MMS_SRV_UNICODE_STRING_OFFSET);
 182 +       *mms_string_e  = (char *)(data + MMS_SRV_UNICODE_STRING_OFFSET + unicode_size * 2);
 183 +       *mms_padding_e = (char *)(data + datalen); /* looks funny, doesn't it */
 184 +       return 0;
 185 +}
 186 +
 187 +
 188 +static int help(const struct iphdr *iph, size_t len,
 189 +               struct ip_conntrack *ct,
 190 +               enum ip_conntrack_info ctinfo)
 191 +{
 192 +       /* tcplen not negative guaranteed by ip_conntrack_tcp.c */
 193 +       struct tcphdr *tcph = (void *)iph + iph->ihl * 4;
 194 +       const char *data = (const char *)tcph + tcph->doff * 4;
 195 +       unsigned int tcplen = len - iph->ihl * 4;
 196 +       unsigned int datalen = tcplen - tcph->doff * 4;
 197 +       int dir = CTINFO2DIR(ctinfo);
 198 +       struct ip_conntrack_expect expect, *exp = &expect;
 199 +       struct ip_ct_mms_expect *exp_mms_info = &exp->help.exp_mms_info;
 200 +
 201 +       u_int32_t mms_ip;
 202 +       u_int16_t mms_proto;
 203 +       char mms_proto_string[8];
 204 +       u_int16_t mms_port;
 205 +       char *mms_string_b, *mms_string_e, *mms_padding_e;
 206 +
 207 +       /* Until there's been traffic both ways, don't look in packets. */
 208 +       if (ctinfo != IP_CT_ESTABLISHED
 209 +           && ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) {
 210 +               DEBUGP("ip_conntrack_mms: Conntrackinfo = %u\n", ctinfo);
 211 +               return NF_ACCEPT;
 212 +       }
 213 +
 214 +       /* Not whole TCP header? */
 215 +       if (tcplen < sizeof(struct tcphdr) || tcplen < tcph->doff*4) {
 216 +               DEBUGP("ip_conntrack_mms: tcplen = %u\n", (unsigned)tcplen);
 217 +               return NF_ACCEPT;
 218 +       }
 219 +
 220 +       /* Checksum invalid?  Ignore. */
 221 +       if (tcp_v4_check(tcph, tcplen, iph->saddr, iph->daddr,
 222 +           csum_partial((char *)tcph, tcplen, 0))) {
 223 +               DEBUGP("mms_help: bad csum: %p %u %u.%u.%u.%u %u.%u.%u.%u\n",
 224 +                      tcph, tcplen, NIPQUAD(iph->saddr),
 225 +                      NIPQUAD(iph->daddr));
 226 +               return NF_ACCEPT;
 227 +       }
 228 +
 229 +       /* Only look at packets with 0x00030002/196610 on bytes 36->39 of TCP payload */
 230 +       if( (MMS_SRV_MSG_OFFSET < datalen) &&
 231 +           ((*(u32 *)(data+MMS_SRV_MSG_OFFSET)) == MMS_SRV_MSG_ID)) {
 232 +               DEBUGP("ip_conntrack_mms: offset 37: %u %u %u %u, datalen:%u\n",
 233 +                      (u8)*(data+36), (u8)*(data+37),
 234 +                      (u8)*(data+38), (u8)*(data+39),
 235 +                      datalen);
 236 +               if(parse_mms(data, datalen, &mms_ip, &mms_proto, &mms_port,
 237 +                            &mms_string_b, &mms_string_e, &mms_padding_e))
 238 +                       if(net_ratelimit())
 239 +                               printk(KERN_WARNING
 240 +                                      "ip_conntrack_mms: Unable to parse data payload\n");
 241 +
 242 +               memset(&expect, 0, sizeof(expect));
 243 +
 244 +               sprintf(mms_proto_string, "(%u)", mms_proto);
 245 +               DEBUGP("ip_conntrack_mms: adding %s expectation %u.%u.%u.%u -> %u.%u.%u.%u:%u\n",
 246 +                      mms_proto == IPPROTO_TCP ? "TCP"
 247 +                      : mms_proto == IPPROTO_UDP ? "UDP":mms_proto_string,
 248 +                      NIPQUAD(ct->tuplehash[!dir].tuple.src.ip),
 249 +                      NIPQUAD(mms_ip),
 250 +                      mms_port);
 251 +
 252 +               /* it's possible that the client will just ask the server to tunnel
 253 +                  the stream over the same TCP session (from port 1755): there's
 254 +                  shouldn't be a need to add an expectation in that case, but it
 255 +                  makes NAT packet mangling so much easier */
 256 +               LOCK_BH(&ip_mms_lock);
 257 +
 258 +               DEBUGP("ip_conntrack_mms: tcph->seq = %u\n", tcph->seq);
 259 +
 260 +               exp->seq = ntohl(tcph->seq) + (mms_string_b - data);
 261 +               exp_mms_info->len     = (mms_string_e  - mms_string_b);
 262 +               exp_mms_info->padding = (mms_padding_e - mms_string_e);
 263 +               exp_mms_info->port    = mms_port;
 264 +
 265 +               DEBUGP("ip_conntrack_mms: wrote info seq=%u (ofs=%u), len=%d, padding=%u\n",
 266 +                      exp->seq, (mms_string_e - data), exp_mms_info->len, exp_mms_info->padding);
 267 +
 268 +               exp->tuple = ((struct ip_conntrack_tuple)
 269 +                             { { ct->tuplehash[!dir].tuple.src.ip, { 0 } },
 270 +                             { mms_ip,
 271 +                               { (__u16) ntohs(mms_port) },
 272 +                               mms_proto } }
 273 +                            );
 274 +               exp->mask  = ((struct ip_conntrack_tuple)
 275 +                            { { 0xFFFFFFFF, { 0 } },
 276 +                              { 0xFFFFFFFF, { 0xFFFF }, 0xFFFF }});
 277 +               exp->expectfn = NULL;
 278 +               ip_conntrack_expect_related(ct, &expect);
 279 +               UNLOCK_BH(&ip_mms_lock);
 280 +       }
 281 +
 282 +       return NF_ACCEPT;
 283 +}
 284 +
 285 +static struct ip_conntrack_helper mms[MAX_PORTS];
 286 +static char mms_names[MAX_PORTS][10];
 287 +
 288 +/* Not __exit: called from init() */
 289 +static void fini(void)
 290 +{
 291 +       int i;
 292 +       for (i = 0; (i < MAX_PORTS) && ports[i]; i++) {
 293 +               DEBUGP("ip_conntrack_mms: unregistering helper for port %d\n",
 294 +                               ports[i]);
 295 +               ip_conntrack_helper_unregister(&mms[i]);
 296 +       }
 297 +}
 298 +
 299 +static int __init init(void)
 300 +{
 301 +       int i, ret;
 302 +       char *tmpname;
 303 +
 304 +       if (ports[0] == 0)
 305 +               ports[0] = MMS_PORT;
 306 +
 307 +       for (i = 0; (i < MAX_PORTS) && ports[i]; i++) {
 308 +               memset(&mms[i], 0, sizeof(struct ip_conntrack_helper));
 309 +               mms[i].tuple.src.u.tcp.port = htons(ports[i]);
 310 +               mms[i].tuple.dst.protonum = IPPROTO_TCP;
 311 +               mms[i].mask.src.u.tcp.port = 0xFFFF;
 312 +               mms[i].mask.dst.protonum = 0xFFFF;
 313 +               mms[i].max_expected = 1;
 314 +               mms[i].timeout = 0;
 315 +               mms[i].flags = IP_CT_HELPER_F_REUSE_EXPECT;
 316 +               mms[i].me = THIS_MODULE;
 317 +               mms[i].help = help;
 318 +
 319 +               tmpname = &mms_names[i][0];
 320 +               if (ports[i] == MMS_PORT)
 321 +                       sprintf(tmpname, "mms");
 322 +               else
 323 +                       sprintf(tmpname, "mms-%d", ports[i]);
 324 +               mms[i].name = tmpname;
 325 +
 326 +               DEBUGP("ip_conntrack_mms: registering helper for port %d\n",
 327 +                               ports[i]);
 328 +               ret = ip_conntrack_helper_register(&mms[i]);
 329 +
 330 +               if (ret) {
 331 +                       fini();
 332 +                       return ret;
 333 +               }
 334 +               ports_c++;
 335 +       }
 336 +       return 0;
 337 +}
 338 +
 339 +module_init(init);
 340 +module_exit(fini);
 341 --- /dev/null
 342 +++ b/net/ipv4/netfilter/ip_nat_mms.c
 343 @@ -0,0 +1,330 @@
 344 +/* MMS extension for TCP NAT alteration.
 345 + * (C) 2002 by Filip Sneppe <filip.sneppe@cronos.be>
 346 + * based on ip_nat_ftp.c and ip_nat_irc.c
 347 + *
 348 + * ip_nat_mms.c v0.3 2002-09-22
 349 + *
 350 + *      This program is free software; you can redistribute it and/or
 351 + *      modify it under the terms of the GNU General Public License
 352 + *      as published by the Free Software Foundation; either version
 353 + *      2 of the License, or (at your option) any later version.
 354 + *
 355 + *      Module load syntax:
 356 + *      insmod ip_nat_mms.o ports=port1,port2,...port<MAX_PORTS>
 357 + *
 358 + *      Please give the ports of all MMS servers You wish to connect to.
 359 + *      If you don't specify ports, the default will be TCP port 1755.
 360 + *
 361 + *      More info on MMS protocol, firewalls and NAT:
 362 + *      http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnwmt/html/MMSFirewall.asp
 363 + *      http://www.microsoft.com/windows/windowsmedia/serve/firewall.asp
 364 + *
 365 + *      The SDP project people are reverse-engineering MMS:
 366 + *      http://get.to/sdp
 367 + */
 368 +
 369 +
 370 +#include <linux/module.h>
 371 +#include <linux/netfilter_ipv4.h>
 372 +#include <linux/ip.h>
 373 +#include <linux/tcp.h>
 374 +#include <net/tcp.h>
 375 +#include <linux/netfilter_ipv4/ip_nat.h>
 376 +#include <linux/netfilter_ipv4/ip_nat_helper.h>
 377 +#include <linux/netfilter_ipv4/ip_nat_rule.h>
 378 +#include <linux/netfilter_ipv4/ip_conntrack_mms.h>
 379 +#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
 380 +
 381 +#define DEBUGP(format, args...)
 382 +#define DUMP_BYTES(address, counter)
 383 +
 384 +#define MAX_PORTS 8
 385 +static int ports[MAX_PORTS];
 386 +static int ports_c = 0;
 387 +
 388 +#ifdef MODULE_PARM
 389 +MODULE_PARM(ports, "1-" __MODULE_STRING(MAX_PORTS) "i");
 390 +#endif
 391 +
 392 +MODULE_AUTHOR("Filip Sneppe <filip.sneppe@cronos.be>");
 393 +MODULE_DESCRIPTION("Microsoft Windows Media Services (MMS) NAT module");
 394 +MODULE_LICENSE("GPL");
 395 +
 396 +DECLARE_LOCK_EXTERN(ip_mms_lock);
 397 +
 398 +
 399 +static int mms_data_fixup(const struct ip_ct_mms_expect *ct_mms_info,
 400 +                          struct ip_conntrack *ct,
 401 +                          struct sk_buff **pskb,
 402 +                          enum ip_conntrack_info ctinfo,
 403 +                          struct ip_conntrack_expect *expect)
 404 +{
 405 +       u_int32_t newip;
 406 +       struct ip_conntrack_tuple t;
 407 +       struct iphdr *iph = (*pskb)->nh.iph;
 408 +       struct tcphdr *tcph = (void *) iph + iph->ihl * 4;
 409 +       char *data = (char *)tcph + tcph->doff * 4;
 410 +       int i, j, k, port;
 411 +       u_int16_t mms_proto;
 412 +
 413 +       u_int32_t *mms_chunkLenLV    = (u_int32_t *)(data + MMS_SRV_CHUNKLENLV_OFFSET);
 414 +       u_int32_t *mms_chunkLenLM    = (u_int32_t *)(data + MMS_SRV_CHUNKLENLM_OFFSET);
 415 +       u_int32_t *mms_messageLength = (u_int32_t *)(data + MMS_SRV_MESSAGELENGTH_OFFSET);
 416 +
 417 +       int zero_padding;
 418 +
 419 +       char buffer[28];         /* "\\255.255.255.255\UDP\65635" * 2 (for unicode) */
 420 +       char unicode_buffer[75]; /* 27*2 (unicode) + 20 + 1 */
 421 +       char proto_string[6];
 422 +
 423 +       MUST_BE_LOCKED(&ip_mms_lock);
 424 +
 425 +       /* what was the protocol again ? */
 426 +       mms_proto = expect->tuple.dst.protonum;
 427 +       sprintf(proto_string, "%u", mms_proto);
 428 +
 429 +       DEBUGP("ip_nat_mms: mms_data_fixup: info (seq %u + %u) in %u, proto %s\n",
 430 +              expect->seq, ct_mms_info->len, ntohl(tcph->seq),
 431 +              mms_proto == IPPROTO_UDP ? "UDP"
 432 +              : mms_proto == IPPROTO_TCP ? "TCP":proto_string);
 433 +
 434 +       newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
 435 +
 436 +       /* Alter conntrack's expectations. */
 437 +       t = expect->tuple;
 438 +       t.dst.ip = newip;
 439 +       for (port = ct_mms_info->port; port != 0; port++) {
 440 +               t.dst.u.tcp.port = htons(port);
 441 +               if (ip_conntrack_change_expect(expect, &t) == 0) {
 442 +                       DEBUGP("ip_nat_mms: mms_data_fixup: using port %d\n", port);
 443 +                       break;
 444 +               }
 445 +       }
 446 +
 447 +       if(port == 0)
 448 +               return 0;
 449 +
 450 +       sprintf(buffer, "\\\\%u.%u.%u.%u\\%s\\%u",
 451 +               NIPQUAD(newip),
 452 +               expect->tuple.dst.protonum == IPPROTO_UDP ? "UDP"
 453 +               : expect->tuple.dst.protonum == IPPROTO_TCP ? "TCP":proto_string,
 454 +               port);
 455 +       DEBUGP("ip_nat_mms: new unicode string=%s\n", buffer);
 456 +
 457 +       memset(unicode_buffer, 0, sizeof(char)*75);
 458 +
 459 +       for (i=0; i<strlen(buffer); ++i)
 460 +               *(unicode_buffer+i*2)=*(buffer+i);
 461 +
 462 +       DEBUGP("ip_nat_mms: mms_data_fixup: padding: %u len: %u\n", ct_mms_info->padding, ct_mms_info->len);
 463 +       DEBUGP("ip_nat_mms: mms_data_fixup: offset: %u\n", MMS_SRV_UNICODE_STRING_OFFSET+ct_mms_info->len);
 464 +       DUMP_BYTES(data+MMS_SRV_UNICODE_STRING_OFFSET, 60);
 465 +
 466 +       /* add end of packet to it */
 467 +       for (j=0; j<ct_mms_info->padding; ++j) {
 468 +               DEBUGP("ip_nat_mms: mms_data_fixup: i=%u j=%u byte=%u\n",
 469 +                      i, j, (u8)*(data+MMS_SRV_UNICODE_STRING_OFFSET+ct_mms_info->len+j));
 470 +               *(unicode_buffer+i*2+j) = *(data+MMS_SRV_UNICODE_STRING_OFFSET+ct_mms_info->len+j);
 471 +       }
 472 +
 473 +       /* pad with zeroes at the end ? see explanation of weird math below */
 474 +       zero_padding = (8-(strlen(buffer)*2 + ct_mms_info->padding + 4)%8)%8;
 475 +       for (k=0; k<zero_padding; ++k)
 476 +               *(unicode_buffer+i*2+j+k)= (char)0;
 477 +
 478 +       DEBUGP("ip_nat_mms: mms_data_fixup: zero_padding = %u\n", zero_padding);
 479 +       DEBUGP("ip_nat_mms: original=> chunkLenLV=%u chunkLenLM=%u messageLength=%u\n",
 480 +              *mms_chunkLenLV, *mms_chunkLenLM, *mms_messageLength);
 481 +
 482 +       /* explanation, before I forget what I did:
 483 +          strlen(buffer)*2 + ct_mms_info->padding + 4 must be divisable by 8;
 484 +          divide by 8 and add 3 to compute the mms_chunkLenLM field,
 485 +          but note that things may have to be padded with zeroes to align by 8
 486 +          bytes, hence we add 7 and divide by 8 to get the correct length */
 487 +       *mms_chunkLenLM    = (u_int32_t) (3+(strlen(buffer)*2+ct_mms_info->padding+11)/8);
 488 +       *mms_chunkLenLV    = *mms_chunkLenLM+2;
 489 +       *mms_messageLength = *mms_chunkLenLV*8;
 490 +
 491 +       DEBUGP("ip_nat_mms: modified=> chunkLenLV=%u chunkLenLM=%u messageLength=%u\n",
 492 +              *mms_chunkLenLV, *mms_chunkLenLM, *mms_messageLength);
 493 +
 494 +       ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
 495 +                                expect->seq - ntohl(tcph->seq),
 496 +                                ct_mms_info->len + ct_mms_info->padding, unicode_buffer,
 497 +                                strlen(buffer)*2 + ct_mms_info->padding + zero_padding);
 498 +       DUMP_BYTES(unicode_buffer, 60);
 499 +
 500 +       return 1;
 501 +}
 502 +
 503 +static unsigned int
 504 +mms_nat_expected(struct sk_buff **pskb,
 505 +                 unsigned int hooknum,
 506 +                 struct ip_conntrack *ct,
 507 +                 struct ip_nat_info *info)
 508 +{
 509 +       struct ip_nat_multi_range mr;
 510 +       u_int32_t newdstip, newsrcip, newip;
 511 +
 512 +       struct ip_conntrack *master = master_ct(ct);
 513 +
 514 +       IP_NF_ASSERT(info);
 515 +       IP_NF_ASSERT(master);
 516 +
 517 +       IP_NF_ASSERT(!(info->initialized & (1 << HOOK2MANIP(hooknum))));
 518 +
 519 +       DEBUGP("ip_nat_mms: mms_nat_expected: We have a connection!\n");
 520 +
 521 +       newdstip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
 522 +       newsrcip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
 523 +       DEBUGP("ip_nat_mms: mms_nat_expected: hook %s: newsrc->newdst %u.%u.%u.%u->%u.%u.%u.%u\n",
 524 +              hooknum == NF_IP_POST_ROUTING ? "POSTROUTING"
 525 +              : hooknum == NF_IP_PRE_ROUTING ? "PREROUTING"
 526 +              : hooknum == NF_IP_LOCAL_OUT ? "OUTPUT" : "???",
 527 +              NIPQUAD(newsrcip), NIPQUAD(newdstip));
 528 +
 529 +       if (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC)
 530 +               newip = newsrcip;
 531 +       else
 532 +               newip = newdstip;
 533 +
 534 +       DEBUGP("ip_nat_mms: mms_nat_expected: IP to %u.%u.%u.%u\n", NIPQUAD(newip));
 535 +
 536 +       mr.rangesize = 1;
 537 +       /* We don't want to manip the per-protocol, just the IPs. */
 538 +       mr.range[0].flags = IP_NAT_RANGE_MAP_IPS;
 539 +       mr.range[0].min_ip = mr.range[0].max_ip = newip;
 540 +
 541 +       return ip_nat_setup_info(ct, &mr, hooknum);
 542 +}
 543 +
 544 +
 545 +static unsigned int mms_nat_help(struct ip_conntrack *ct,
 546 +                        struct ip_conntrack_expect *exp,
 547 +                        struct ip_nat_info *info,
 548 +                        enum ip_conntrack_info ctinfo,
 549 +                        unsigned int hooknum,
 550 +                        struct sk_buff **pskb)
 551 +{
 552 +       struct iphdr *iph = (*pskb)->nh.iph;
 553 +       struct tcphdr *tcph = (void *) iph + iph->ihl * 4;
 554 +       unsigned int datalen;
 555 +       int dir;
 556 +       struct ip_ct_mms_expect *ct_mms_info;
 557 +
 558 +       if (!exp)
 559 +               DEBUGP("ip_nat_mms: no exp!!");
 560 +
 561 +       ct_mms_info = &exp->help.exp_mms_info;
 562 +
 563 +       /* Only mangle things once: original direction in POST_ROUTING
 564 +          and reply direction on PRE_ROUTING. */
 565 +       dir = CTINFO2DIR(ctinfo);
 566 +       if (!((hooknum == NF_IP_POST_ROUTING && dir == IP_CT_DIR_ORIGINAL)
 567 +           ||(hooknum == NF_IP_PRE_ROUTING && dir == IP_CT_DIR_REPLY))) {
 568 +               DEBUGP("ip_nat_mms: mms_nat_help: not touching dir %s at hook %s\n",
 569 +                      dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY",
 570 +                      hooknum == NF_IP_POST_ROUTING ? "POSTROUTING"
 571 +                      : hooknum == NF_IP_PRE_ROUTING ? "PREROUTING"
 572 +                      : hooknum == NF_IP_LOCAL_OUT ? "OUTPUT" : "???");
 573 +               return NF_ACCEPT;
 574 +       }
 575 +       DEBUGP("ip_nat_mms: mms_nat_help: beyond not touching (dir %s at hook %s)\n",
 576 +              dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY",
 577 +              hooknum == NF_IP_POST_ROUTING ? "POSTROUTING"
 578 +              : hooknum == NF_IP_PRE_ROUTING ? "PREROUTING"
 579 +              : hooknum == NF_IP_LOCAL_OUT ? "OUTPUT" : "???");
 580 +
 581 +       datalen = (*pskb)->len - iph->ihl * 4 - tcph->doff * 4;
 582 +
 583 +       DEBUGP("ip_nat_mms: mms_nat_help: %u+%u=%u %u %u\n", exp->seq, ct_mms_info->len,
 584 +              exp->seq + ct_mms_info->len,
 585 +              ntohl(tcph->seq),
 586 +              ntohl(tcph->seq) + datalen);
 587 +
 588 +       LOCK_BH(&ip_mms_lock);
 589 +       /* Check wether the whole IP/proto/port pattern is carried in the payload */
 590 +       if (between(exp->seq + ct_mms_info->len,
 591 +           ntohl(tcph->seq),
 592 +           ntohl(tcph->seq) + datalen)) {
 593 +               if (!mms_data_fixup(ct_mms_info, ct, pskb, ctinfo, exp)) {
 594 +                       UNLOCK_BH(&ip_mms_lock);
 595 +                       return NF_DROP;
 596 +               }
 597 +       } else {
 598 +               /* Half a match?  This means a partial retransmisison.
 599 +                  It's a cracker being funky. */
 600 +               if (net_ratelimit()) {
 601 +                       printk("ip_nat_mms: partial packet %u/%u in %u/%u\n",
 602 +                              exp->seq, ct_mms_info->len,
 603 +                              ntohl(tcph->seq),
 604 +                              ntohl(tcph->seq) + datalen);
 605 +               }
 606 +               UNLOCK_BH(&ip_mms_lock);
 607 +               return NF_DROP;
 608 +       }
 609 +       UNLOCK_BH(&ip_mms_lock);
 610 +
 611 +       return NF_ACCEPT;
 612 +}
 613 +
 614 +static struct ip_nat_helper mms[MAX_PORTS];
 615 +static char mms_names[MAX_PORTS][10];
 616 +
 617 +/* Not __exit: called from init() */
 618 +static void fini(void)
 619 +{
 620 +       int i;
 621 +
 622 +       for (i = 0; (i < MAX_PORTS) && ports[i]; i++) {
 623 +               DEBUGP("ip_nat_mms: unregistering helper for port %d\n", ports[i]);
 624 +               ip_nat_helper_unregister(&mms[i]);
 625 +       }
 626 +}
 627 +
 628 +static int __init init(void)
 629 +{
 630 +       int i, ret = 0;
 631 +       char *tmpname;
 632 +
 633 +       if (ports[0] == 0)
 634 +               ports[0] = MMS_PORT;
 635 +
 636 +       for (i = 0; (i < MAX_PORTS) && ports[i]; i++) {
 637 +
 638 +               memset(&mms[i], 0, sizeof(struct ip_nat_helper));
 639 +
 640 +               mms[i].tuple.dst.protonum = IPPROTO_TCP;
 641 +               mms[i].tuple.src.u.tcp.port = htons(ports[i]);
 642 +               mms[i].mask.dst.protonum = 0xFFFF;
 643 +               mms[i].mask.src.u.tcp.port = 0xFFFF;
 644 +               mms[i].help = mms_nat_help;
 645 +               mms[i].me = THIS_MODULE;
 646 +               mms[i].flags = 0;
 647 +               mms[i].expect = mms_nat_expected;
 648 +
 649 +               tmpname = &mms_names[i][0];
 650 +               if (ports[i] == MMS_PORT)
 651 +                       sprintf(tmpname, "mms");
 652 +               else
 653 +                       sprintf(tmpname, "mms-%d", i);
 654 +               mms[i].name = tmpname;
 655 +
 656 +               DEBUGP("ip_nat_mms: register helper for port %d\n",
 657 +                               ports[i]);
 658 +               ret = ip_nat_helper_register(&mms[i]);
 659 +
 660 +               if (ret) {
 661 +                       printk("ip_nat_mms: error registering "
 662 +                              "helper for port %d\n", ports[i]);
 663 +                       fini();
 664 +                       return ret;
 665 +               }
 666 +               ports_c++;
 667 +       }
 668 +
 669 +       return ret;
 670 +}
 671 +
 672 +module_init(init);
 673 +module_exit(fini);
 674 --- a/include/linux/netfilter_ipv4/ip_conntrack.h
 675 +++ b/include/linux/netfilter_ipv4/ip_conntrack.h
 676 @@ -69,6 +69,7 @@ union ip_conntrack_expect_proto {
 677  #include <linux/netfilter_ipv4/ip_conntrack_irc.h>
 678  #include <linux/netfilter_ipv4/ip_conntrack_h323.h>
 679  #include <linux/netfilter_ipv4/ip_conntrack_rtsp.h>
 680 +#include <linux/netfilter_ipv4/ip_conntrack_mms.h>
 681
 682  /* per expectation: application helper private data */
 683  union ip_conntrack_expect_help {
 684 @@ -78,6 +79,7 @@ union ip_conntrack_expect_help {
 685         struct ip_ct_irc_expect exp_irc_info;
 686         struct ip_ct_h225_expect exp_h225_info;
 687         struct ip_ct_rtsp_expect exp_rtsp_info;
 688 +       struct ip_ct_mms_expect exp_mms_info;
 689
 690  #ifdef CONFIG_IP_NF_NAT_NEEDED
 691         union {
 692 @@ -93,6 +95,7 @@ union ip_conntrack_help {
 693         struct ip_ct_irc_master ct_irc_info;
 694         struct ip_ct_h225_master ct_h225_info;
 695         struct ip_ct_rtsp_master ct_rtsp_info;
 696 +       struct ip_ct_mms_master ct_mms_info;
 697  };
 698
 699  #ifdef CONFIG_IP_NF_NAT_NEEDED
 700 --- /dev/null
 701 +++ b/include/linux/netfilter_ipv4/ip_conntrack_mms.h
 702 @@ -0,0 +1,31 @@
 703 +#ifndef _IP_CONNTRACK_MMS_H
 704 +#define _IP_CONNTRACK_MMS_H
 705 +/* MMS tracking. */
 706 +
 707 +#ifdef __KERNEL__
 708 +#include <linux/netfilter_ipv4/lockhelp.h>
 709 +
 710 +DECLARE_LOCK_EXTERN(ip_mms_lock);
 711 +
 712 +#define MMS_PORT                         1755
 713 +#define MMS_SRV_MSG_ID                   196610
 714 +
 715 +#define MMS_SRV_MSG_OFFSET               36
 716 +#define MMS_SRV_UNICODE_STRING_OFFSET    60
 717 +#define MMS_SRV_CHUNKLENLV_OFFSET        16
 718 +#define MMS_SRV_CHUNKLENLM_OFFSET        32
 719 +#define MMS_SRV_MESSAGELENGTH_OFFSET     8
 720 +#endif
 721 +
 722 +/* This structure is per expected connection */
 723 +struct ip_ct_mms_expect {
 724 +       u_int32_t len;
 725 +       u_int32_t padding;
 726 +       u_int16_t port;
 727 +};
 728 +
 729 +/* This structure exists only once per master */
 730 +struct ip_ct_mms_master {
 731 +};
 732 +
 733 +#endif /* _IP_CONNTRACK_MMS_H */