Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* FTP extension for IP connection tracking. */ |
| 2 | |
| 3 | /* (C) 1999-2001 Paul `Rusty' Russell |
| 4 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | */ |
| 10 | |
| 11 | #include <linux/config.h> |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/netfilter.h> |
| 14 | #include <linux/ip.h> |
| 15 | #include <linux/ctype.h> |
| 16 | #include <net/checksum.h> |
| 17 | #include <net/tcp.h> |
| 18 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #include <linux/netfilter_ipv4/ip_conntrack_helper.h> |
| 20 | #include <linux/netfilter_ipv4/ip_conntrack_ftp.h> |
| 21 | #include <linux/moduleparam.h> |
| 22 | |
| 23 | MODULE_LICENSE("GPL"); |
| 24 | MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>"); |
| 25 | MODULE_DESCRIPTION("ftp connection tracking helper"); |
| 26 | |
| 27 | /* This is slow, but it's simple. --RR */ |
| 28 | static char ftp_buffer[65536]; |
| 29 | |
Patrick McHardy | e45b1be | 2005-06-21 14:01:30 -0700 | [diff] [blame] | 30 | static DEFINE_SPINLOCK(ip_ftp_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | |
| 32 | #define MAX_PORTS 8 |
| 33 | static int ports[MAX_PORTS]; |
| 34 | static int ports_c; |
| 35 | module_param_array(ports, int, &ports_c, 0400); |
| 36 | |
| 37 | static int loose; |
| 38 | module_param(loose, int, 0600); |
| 39 | |
| 40 | unsigned int (*ip_nat_ftp_hook)(struct sk_buff **pskb, |
| 41 | enum ip_conntrack_info ctinfo, |
| 42 | enum ip_ct_ftp_type type, |
| 43 | unsigned int matchoff, |
| 44 | unsigned int matchlen, |
| 45 | struct ip_conntrack_expect *exp, |
| 46 | u32 *seq); |
| 47 | EXPORT_SYMBOL_GPL(ip_nat_ftp_hook); |
| 48 | |
| 49 | #if 0 |
| 50 | #define DEBUGP printk |
| 51 | #else |
| 52 | #define DEBUGP(format, args...) |
| 53 | #endif |
| 54 | |
| 55 | static int try_rfc959(const char *, size_t, u_int32_t [], char); |
| 56 | static int try_eprt(const char *, size_t, u_int32_t [], char); |
| 57 | static int try_epsv_response(const char *, size_t, u_int32_t [], char); |
| 58 | |
| 59 | static struct ftp_search { |
| 60 | enum ip_conntrack_dir dir; |
| 61 | const char *pattern; |
| 62 | size_t plen; |
| 63 | char skip; |
| 64 | char term; |
| 65 | enum ip_ct_ftp_type ftptype; |
| 66 | int (*getnum)(const char *, size_t, u_int32_t[], char); |
| 67 | } search[] = { |
| 68 | { |
| 69 | IP_CT_DIR_ORIGINAL, |
| 70 | "PORT", sizeof("PORT") - 1, ' ', '\r', |
| 71 | IP_CT_FTP_PORT, |
| 72 | try_rfc959, |
| 73 | }, |
| 74 | { |
| 75 | IP_CT_DIR_REPLY, |
| 76 | "227 ", sizeof("227 ") - 1, '(', ')', |
| 77 | IP_CT_FTP_PASV, |
| 78 | try_rfc959, |
| 79 | }, |
| 80 | { |
| 81 | IP_CT_DIR_ORIGINAL, |
| 82 | "EPRT", sizeof("EPRT") - 1, ' ', '\r', |
| 83 | IP_CT_FTP_EPRT, |
| 84 | try_eprt, |
| 85 | }, |
| 86 | { |
| 87 | IP_CT_DIR_REPLY, |
| 88 | "229 ", sizeof("229 ") - 1, '(', ')', |
| 89 | IP_CT_FTP_EPSV, |
| 90 | try_epsv_response, |
| 91 | }, |
| 92 | }; |
| 93 | |
| 94 | static int try_number(const char *data, size_t dlen, u_int32_t array[], |
| 95 | int array_size, char sep, char term) |
| 96 | { |
| 97 | u_int32_t i, len; |
| 98 | |
| 99 | memset(array, 0, sizeof(array[0])*array_size); |
| 100 | |
| 101 | /* Keep data pointing at next char. */ |
| 102 | for (i = 0, len = 0; len < dlen && i < array_size; len++, data++) { |
| 103 | if (*data >= '0' && *data <= '9') { |
| 104 | array[i] = array[i]*10 + *data - '0'; |
| 105 | } |
| 106 | else if (*data == sep) |
| 107 | i++; |
| 108 | else { |
| 109 | /* Unexpected character; true if it's the |
| 110 | terminator and we're finished. */ |
| 111 | if (*data == term && i == array_size - 1) |
| 112 | return len; |
| 113 | |
| 114 | DEBUGP("Char %u (got %u nums) `%u' unexpected\n", |
| 115 | len, i, *data); |
| 116 | return 0; |
| 117 | } |
| 118 | } |
| 119 | DEBUGP("Failed to fill %u numbers separated by %c\n", array_size, sep); |
| 120 | |
| 121 | return 0; |
| 122 | } |
| 123 | |
| 124 | /* Returns 0, or length of numbers: 192,168,1,1,5,6 */ |
| 125 | static int try_rfc959(const char *data, size_t dlen, u_int32_t array[6], |
| 126 | char term) |
| 127 | { |
| 128 | return try_number(data, dlen, array, 6, ',', term); |
| 129 | } |
| 130 | |
| 131 | /* Grab port: number up to delimiter */ |
| 132 | static int get_port(const char *data, int start, size_t dlen, char delim, |
| 133 | u_int32_t array[2]) |
| 134 | { |
| 135 | u_int16_t port = 0; |
| 136 | int i; |
| 137 | |
| 138 | for (i = start; i < dlen; i++) { |
| 139 | /* Finished? */ |
| 140 | if (data[i] == delim) { |
| 141 | if (port == 0) |
| 142 | break; |
| 143 | array[0] = port >> 8; |
| 144 | array[1] = port; |
| 145 | return i + 1; |
| 146 | } |
| 147 | else if (data[i] >= '0' && data[i] <= '9') |
| 148 | port = port*10 + data[i] - '0'; |
| 149 | else /* Some other crap */ |
| 150 | break; |
| 151 | } |
| 152 | return 0; |
| 153 | } |
| 154 | |
| 155 | /* Returns 0, or length of numbers: |1|132.235.1.2|6275| */ |
| 156 | static int try_eprt(const char *data, size_t dlen, u_int32_t array[6], |
| 157 | char term) |
| 158 | { |
| 159 | char delim; |
| 160 | int length; |
| 161 | |
| 162 | /* First character is delimiter, then "1" for IPv4, then |
| 163 | delimiter again. */ |
| 164 | if (dlen <= 3) return 0; |
| 165 | delim = data[0]; |
| 166 | if (isdigit(delim) || delim < 33 || delim > 126 |
| 167 | || data[1] != '1' || data[2] != delim) |
| 168 | return 0; |
| 169 | |
| 170 | DEBUGP("EPRT: Got |1|!\n"); |
| 171 | /* Now we have IP address. */ |
| 172 | length = try_number(data + 3, dlen - 3, array, 4, '.', delim); |
| 173 | if (length == 0) |
| 174 | return 0; |
| 175 | |
| 176 | DEBUGP("EPRT: Got IP address!\n"); |
| 177 | /* Start offset includes initial "|1|", and trailing delimiter */ |
| 178 | return get_port(data, 3 + length + 1, dlen, delim, array+4); |
| 179 | } |
| 180 | |
| 181 | /* Returns 0, or length of numbers: |||6446| */ |
| 182 | static int try_epsv_response(const char *data, size_t dlen, u_int32_t array[6], |
| 183 | char term) |
| 184 | { |
| 185 | char delim; |
| 186 | |
| 187 | /* Three delimiters. */ |
| 188 | if (dlen <= 3) return 0; |
| 189 | delim = data[0]; |
| 190 | if (isdigit(delim) || delim < 33 || delim > 126 |
| 191 | || data[1] != delim || data[2] != delim) |
| 192 | return 0; |
| 193 | |
| 194 | return get_port(data, 3, dlen, delim, array+4); |
| 195 | } |
| 196 | |
| 197 | /* Return 1 for match, 0 for accept, -1 for partial. */ |
| 198 | static int find_pattern(const char *data, size_t dlen, |
| 199 | const char *pattern, size_t plen, |
| 200 | char skip, char term, |
| 201 | unsigned int *numoff, |
| 202 | unsigned int *numlen, |
| 203 | u_int32_t array[6], |
| 204 | int (*getnum)(const char *, size_t, u_int32_t[], char)) |
| 205 | { |
| 206 | size_t i; |
| 207 | |
| 208 | DEBUGP("find_pattern `%s': dlen = %u\n", pattern, dlen); |
| 209 | if (dlen == 0) |
| 210 | return 0; |
| 211 | |
| 212 | if (dlen <= plen) { |
| 213 | /* Short packet: try for partial? */ |
| 214 | if (strnicmp(data, pattern, dlen) == 0) |
| 215 | return -1; |
| 216 | else return 0; |
| 217 | } |
| 218 | |
| 219 | if (strnicmp(data, pattern, plen) != 0) { |
| 220 | #if 0 |
| 221 | size_t i; |
| 222 | |
| 223 | DEBUGP("ftp: string mismatch\n"); |
| 224 | for (i = 0; i < plen; i++) { |
| 225 | DEBUGP("ftp:char %u `%c'(%u) vs `%c'(%u)\n", |
| 226 | i, data[i], data[i], |
| 227 | pattern[i], pattern[i]); |
| 228 | } |
| 229 | #endif |
| 230 | return 0; |
| 231 | } |
| 232 | |
| 233 | DEBUGP("Pattern matches!\n"); |
| 234 | /* Now we've found the constant string, try to skip |
| 235 | to the 'skip' character */ |
| 236 | for (i = plen; data[i] != skip; i++) |
| 237 | if (i == dlen - 1) return -1; |
| 238 | |
| 239 | /* Skip over the last character */ |
| 240 | i++; |
| 241 | |
| 242 | DEBUGP("Skipped up to `%c'!\n", skip); |
| 243 | |
| 244 | *numoff = i; |
| 245 | *numlen = getnum(data + i, dlen - i, array, term); |
| 246 | if (!*numlen) |
| 247 | return -1; |
| 248 | |
| 249 | DEBUGP("Match succeeded!\n"); |
| 250 | return 1; |
| 251 | } |
| 252 | |
| 253 | /* Look up to see if we're just after a \n. */ |
Yasuyuki KOZAKAI | f649a3b | 2005-04-25 12:00:04 -0700 | [diff] [blame] | 254 | static int find_nl_seq(u32 seq, const struct ip_ct_ftp_master *info, int dir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 255 | { |
| 256 | unsigned int i; |
| 257 | |
| 258 | for (i = 0; i < info->seq_aft_nl_num[dir]; i++) |
| 259 | if (info->seq_aft_nl[dir][i] == seq) |
| 260 | return 1; |
| 261 | return 0; |
| 262 | } |
| 263 | |
| 264 | /* We don't update if it's older than what we have. */ |
Yasuyuki KOZAKAI | f649a3b | 2005-04-25 12:00:04 -0700 | [diff] [blame] | 265 | static void update_nl_seq(u32 nl_seq, struct ip_ct_ftp_master *info, int dir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 266 | { |
| 267 | unsigned int i, oldest = NUM_SEQ_TO_REMEMBER; |
| 268 | |
| 269 | /* Look for oldest: if we find exact match, we're done. */ |
| 270 | for (i = 0; i < info->seq_aft_nl_num[dir]; i++) { |
| 271 | if (info->seq_aft_nl[dir][i] == nl_seq) |
| 272 | return; |
| 273 | |
| 274 | if (oldest == info->seq_aft_nl_num[dir] |
| 275 | || before(info->seq_aft_nl[dir][i], oldest)) |
| 276 | oldest = i; |
| 277 | } |
| 278 | |
| 279 | if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) |
| 280 | info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq; |
| 281 | else if (oldest != NUM_SEQ_TO_REMEMBER) |
| 282 | info->seq_aft_nl[dir][oldest] = nl_seq; |
| 283 | } |
| 284 | |
| 285 | static int help(struct sk_buff **pskb, |
| 286 | struct ip_conntrack *ct, |
| 287 | enum ip_conntrack_info ctinfo) |
| 288 | { |
| 289 | unsigned int dataoff, datalen; |
| 290 | struct tcphdr _tcph, *th; |
| 291 | char *fb_ptr; |
| 292 | int ret; |
| 293 | u32 seq, array[6] = { 0 }; |
| 294 | int dir = CTINFO2DIR(ctinfo); |
| 295 | unsigned int matchlen, matchoff; |
| 296 | struct ip_ct_ftp_master *ct_ftp_info = &ct->help.ct_ftp_info; |
| 297 | struct ip_conntrack_expect *exp; |
| 298 | unsigned int i; |
| 299 | int found = 0, ends_in_nl; |
| 300 | |
| 301 | /* Until there's been traffic both ways, don't look in packets. */ |
| 302 | if (ctinfo != IP_CT_ESTABLISHED |
| 303 | && ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) { |
| 304 | DEBUGP("ftp: Conntrackinfo = %u\n", ctinfo); |
| 305 | return NF_ACCEPT; |
| 306 | } |
| 307 | |
| 308 | th = skb_header_pointer(*pskb, (*pskb)->nh.iph->ihl*4, |
| 309 | sizeof(_tcph), &_tcph); |
| 310 | if (th == NULL) |
| 311 | return NF_ACCEPT; |
| 312 | |
| 313 | dataoff = (*pskb)->nh.iph->ihl*4 + th->doff*4; |
| 314 | /* No data? */ |
| 315 | if (dataoff >= (*pskb)->len) { |
| 316 | DEBUGP("ftp: pskblen = %u\n", (*pskb)->len); |
| 317 | return NF_ACCEPT; |
| 318 | } |
| 319 | datalen = (*pskb)->len - dataoff; |
| 320 | |
Patrick McHardy | e45b1be | 2005-06-21 14:01:30 -0700 | [diff] [blame] | 321 | spin_lock_bh(&ip_ftp_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | fb_ptr = skb_header_pointer(*pskb, dataoff, |
| 323 | (*pskb)->len - dataoff, ftp_buffer); |
| 324 | BUG_ON(fb_ptr == NULL); |
| 325 | |
| 326 | ends_in_nl = (fb_ptr[datalen - 1] == '\n'); |
| 327 | seq = ntohl(th->seq) + datalen; |
| 328 | |
| 329 | /* Look up to see if we're just after a \n. */ |
| 330 | if (!find_nl_seq(ntohl(th->seq), ct_ftp_info, dir)) { |
| 331 | /* Now if this ends in \n, update ftp info. */ |
| 332 | DEBUGP("ip_conntrack_ftp_help: wrong seq pos %s(%u) or %s(%u)\n", |
| 333 | ct_ftp_info->seq_aft_nl[0][dir] |
| 334 | old_seq_aft_nl_set ? "":"(UNSET) ", old_seq_aft_nl); |
| 335 | ret = NF_ACCEPT; |
| 336 | goto out_update_nl; |
| 337 | } |
| 338 | |
| 339 | /* Initialize IP array to expected address (it's not mentioned |
| 340 | in EPSV responses) */ |
| 341 | array[0] = (ntohl(ct->tuplehash[dir].tuple.src.ip) >> 24) & 0xFF; |
| 342 | array[1] = (ntohl(ct->tuplehash[dir].tuple.src.ip) >> 16) & 0xFF; |
| 343 | array[2] = (ntohl(ct->tuplehash[dir].tuple.src.ip) >> 8) & 0xFF; |
| 344 | array[3] = ntohl(ct->tuplehash[dir].tuple.src.ip) & 0xFF; |
| 345 | |
| 346 | for (i = 0; i < ARRAY_SIZE(search); i++) { |
| 347 | if (search[i].dir != dir) continue; |
| 348 | |
| 349 | found = find_pattern(fb_ptr, (*pskb)->len - dataoff, |
| 350 | search[i].pattern, |
| 351 | search[i].plen, |
| 352 | search[i].skip, |
| 353 | search[i].term, |
| 354 | &matchoff, &matchlen, |
| 355 | array, |
| 356 | search[i].getnum); |
| 357 | if (found) break; |
| 358 | } |
| 359 | if (found == -1) { |
| 360 | /* We don't usually drop packets. After all, this is |
| 361 | connection tracking, not packet filtering. |
| 362 | However, it is necessary for accurate tracking in |
| 363 | this case. */ |
| 364 | if (net_ratelimit()) |
| 365 | printk("conntrack_ftp: partial %s %u+%u\n", |
| 366 | search[i].pattern, |
| 367 | ntohl(th->seq), datalen); |
| 368 | ret = NF_DROP; |
| 369 | goto out; |
| 370 | } else if (found == 0) { /* No match */ |
| 371 | ret = NF_ACCEPT; |
| 372 | goto out_update_nl; |
| 373 | } |
| 374 | |
| 375 | DEBUGP("conntrack_ftp: match `%s' (%u bytes at %u)\n", |
| 376 | fb_ptr + matchoff, matchlen, ntohl(th->seq) + matchoff); |
| 377 | |
| 378 | /* Allocate expectation which will be inserted */ |
| 379 | exp = ip_conntrack_expect_alloc(); |
| 380 | if (exp == NULL) { |
| 381 | ret = NF_DROP; |
| 382 | goto out; |
| 383 | } |
| 384 | |
| 385 | /* We refer to the reverse direction ("!dir") tuples here, |
| 386 | * because we're expecting something in the other direction. |
| 387 | * Doesn't matter unless NAT is happening. */ |
| 388 | exp->tuple.dst.ip = ct->tuplehash[!dir].tuple.dst.ip; |
| 389 | |
| 390 | if (htonl((array[0] << 24) | (array[1] << 16) | (array[2] << 8) | array[3]) |
| 391 | != ct->tuplehash[dir].tuple.src.ip) { |
| 392 | /* Enrico Scholz's passive FTP to partially RNAT'd ftp |
| 393 | server: it really wants us to connect to a |
| 394 | different IP address. Simply don't record it for |
| 395 | NAT. */ |
| 396 | DEBUGP("conntrack_ftp: NOT RECORDING: %u,%u,%u,%u != %u.%u.%u.%u\n", |
| 397 | array[0], array[1], array[2], array[3], |
| 398 | NIPQUAD(ct->tuplehash[dir].tuple.src.ip)); |
| 399 | |
| 400 | /* Thanks to Cristiano Lincoln Mattos |
| 401 | <lincoln@cesar.org.br> for reporting this potential |
| 402 | problem (DMZ machines opening holes to internal |
| 403 | networks, or the packet filter itself). */ |
| 404 | if (!loose) { |
| 405 | ret = NF_ACCEPT; |
| 406 | ip_conntrack_expect_free(exp); |
| 407 | goto out_update_nl; |
| 408 | } |
| 409 | exp->tuple.dst.ip = htonl((array[0] << 24) | (array[1] << 16) |
| 410 | | (array[2] << 8) | array[3]); |
| 411 | } |
| 412 | |
| 413 | exp->tuple.src.ip = ct->tuplehash[!dir].tuple.src.ip; |
| 414 | exp->tuple.dst.u.tcp.port = htons(array[4] << 8 | array[5]); |
| 415 | exp->tuple.src.u.tcp.port = 0; /* Don't care. */ |
| 416 | exp->tuple.dst.protonum = IPPROTO_TCP; |
| 417 | exp->mask = ((struct ip_conntrack_tuple) |
| 418 | { { 0xFFFFFFFF, { 0 } }, |
| 419 | { 0xFFFFFFFF, { .tcp = { 0xFFFF } }, 0xFF }}); |
| 420 | |
| 421 | exp->expectfn = NULL; |
| 422 | exp->master = ct; |
| 423 | |
| 424 | /* Now, NAT might want to mangle the packet, and register the |
| 425 | * (possibly changed) expectation itself. */ |
| 426 | if (ip_nat_ftp_hook) |
| 427 | ret = ip_nat_ftp_hook(pskb, ctinfo, search[i].ftptype, |
| 428 | matchoff, matchlen, exp, &seq); |
| 429 | else { |
| 430 | /* Can't expect this? Best to drop packet now. */ |
| 431 | if (ip_conntrack_expect_related(exp) != 0) { |
| 432 | ip_conntrack_expect_free(exp); |
| 433 | ret = NF_DROP; |
| 434 | } else |
| 435 | ret = NF_ACCEPT; |
| 436 | } |
| 437 | |
| 438 | out_update_nl: |
| 439 | /* Now if this ends in \n, update ftp info. Seq may have been |
| 440 | * adjusted by NAT code. */ |
| 441 | if (ends_in_nl) |
| 442 | update_nl_seq(seq, ct_ftp_info,dir); |
| 443 | out: |
Patrick McHardy | e45b1be | 2005-06-21 14:01:30 -0700 | [diff] [blame] | 444 | spin_unlock_bh(&ip_ftp_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 445 | return ret; |
| 446 | } |
| 447 | |
| 448 | static struct ip_conntrack_helper ftp[MAX_PORTS]; |
| 449 | static char ftp_names[MAX_PORTS][10]; |
| 450 | |
| 451 | /* Not __exit: called from init() */ |
| 452 | static void fini(void) |
| 453 | { |
| 454 | int i; |
| 455 | for (i = 0; i < ports_c; i++) { |
| 456 | DEBUGP("ip_ct_ftp: unregistering helper for port %d\n", |
| 457 | ports[i]); |
| 458 | ip_conntrack_helper_unregister(&ftp[i]); |
| 459 | } |
| 460 | } |
| 461 | |
| 462 | static int __init init(void) |
| 463 | { |
| 464 | int i, ret; |
| 465 | char *tmpname; |
| 466 | |
| 467 | if (ports_c == 0) |
| 468 | ports[ports_c++] = FTP_PORT; |
| 469 | |
| 470 | for (i = 0; i < ports_c; i++) { |
| 471 | ftp[i].tuple.src.u.tcp.port = htons(ports[i]); |
| 472 | ftp[i].tuple.dst.protonum = IPPROTO_TCP; |
| 473 | ftp[i].mask.src.u.tcp.port = 0xFFFF; |
| 474 | ftp[i].mask.dst.protonum = 0xFF; |
| 475 | ftp[i].max_expected = 1; |
| 476 | ftp[i].timeout = 5 * 60; /* 5 minutes */ |
| 477 | ftp[i].me = THIS_MODULE; |
| 478 | ftp[i].help = help; |
| 479 | |
| 480 | tmpname = &ftp_names[i][0]; |
| 481 | if (ports[i] == FTP_PORT) |
| 482 | sprintf(tmpname, "ftp"); |
| 483 | else |
| 484 | sprintf(tmpname, "ftp-%d", ports[i]); |
| 485 | ftp[i].name = tmpname; |
| 486 | |
| 487 | DEBUGP("ip_ct_ftp: registering helper for port %d\n", |
| 488 | ports[i]); |
| 489 | ret = ip_conntrack_helper_register(&ftp[i]); |
| 490 | |
| 491 | if (ret) { |
| 492 | fini(); |
| 493 | return ret; |
| 494 | } |
| 495 | } |
| 496 | return 0; |
| 497 | } |
| 498 | |
| 499 | module_init(init); |
| 500 | module_exit(fini); |