Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * ip_vs_app.c: Application module support for IPVS |
| 3 | * |
| 4 | * Version: $Id: ip_vs_app.c,v 1.17 2003/03/22 06:31:21 wensong Exp $ |
| 5 | * |
| 6 | * Authors: Wensong Zhang <wensong@linuxvirtualserver.org> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU General Public License |
| 10 | * as published by the Free Software Foundation; either version |
| 11 | * 2 of the License, or (at your option) any later version. |
| 12 | * |
| 13 | * Most code here is taken from ip_masq_app.c in kernel 2.2. The difference |
| 14 | * is that ip_vs_app module handles the reverse direction (incoming requests |
| 15 | * and outgoing responses). |
| 16 | * |
| 17 | * IP_MASQ_APP application masquerading module |
| 18 | * |
| 19 | * Author: Juan Jose Ciarlante, <jjciarla@raiz.uncu.edu.ar> |
| 20 | * |
| 21 | */ |
| 22 | |
| 23 | #include <linux/module.h> |
| 24 | #include <linux/kernel.h> |
| 25 | #include <linux/skbuff.h> |
| 26 | #include <linux/in.h> |
| 27 | #include <linux/ip.h> |
| 28 | #include <net/protocol.h> |
Arnaldo Carvalho de Melo | c752f07 | 2005-08-09 20:08:28 -0700 | [diff] [blame] | 29 | #include <net/tcp.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | #include <asm/system.h> |
| 31 | #include <linux/stat.h> |
| 32 | #include <linux/proc_fs.h> |
| 33 | #include <linux/seq_file.h> |
| 34 | |
| 35 | #include <net/ip_vs.h> |
| 36 | |
| 37 | EXPORT_SYMBOL(register_ip_vs_app); |
| 38 | EXPORT_SYMBOL(unregister_ip_vs_app); |
| 39 | EXPORT_SYMBOL(register_ip_vs_app_inc); |
| 40 | |
| 41 | /* ipvs application list head */ |
| 42 | static LIST_HEAD(ip_vs_app_list); |
| 43 | static DECLARE_MUTEX(__ip_vs_app_mutex); |
| 44 | |
| 45 | |
| 46 | /* |
| 47 | * Get an ip_vs_app object |
| 48 | */ |
| 49 | static inline int ip_vs_app_get(struct ip_vs_app *app) |
| 50 | { |
| 51 | /* test and get the module atomically */ |
| 52 | if (app->module) |
| 53 | return try_module_get(app->module); |
| 54 | else |
| 55 | return 1; |
| 56 | } |
| 57 | |
| 58 | |
| 59 | static inline void ip_vs_app_put(struct ip_vs_app *app) |
| 60 | { |
| 61 | if (app->module) |
| 62 | module_put(app->module); |
| 63 | } |
| 64 | |
| 65 | |
| 66 | /* |
| 67 | * Allocate/initialize app incarnation and register it in proto apps. |
| 68 | */ |
| 69 | static int |
| 70 | ip_vs_app_inc_new(struct ip_vs_app *app, __u16 proto, __u16 port) |
| 71 | { |
| 72 | struct ip_vs_protocol *pp; |
| 73 | struct ip_vs_app *inc; |
| 74 | int ret; |
| 75 | |
| 76 | if (!(pp = ip_vs_proto_get(proto))) |
| 77 | return -EPROTONOSUPPORT; |
| 78 | |
| 79 | if (!pp->unregister_app) |
| 80 | return -EOPNOTSUPP; |
| 81 | |
| 82 | inc = kmalloc(sizeof(struct ip_vs_app), GFP_KERNEL); |
| 83 | if (!inc) |
| 84 | return -ENOMEM; |
| 85 | memcpy(inc, app, sizeof(*inc)); |
| 86 | INIT_LIST_HEAD(&inc->p_list); |
| 87 | INIT_LIST_HEAD(&inc->incs_list); |
| 88 | inc->app = app; |
| 89 | inc->port = htons(port); |
| 90 | atomic_set(&inc->usecnt, 0); |
| 91 | |
| 92 | if (app->timeouts) { |
| 93 | inc->timeout_table = |
| 94 | ip_vs_create_timeout_table(app->timeouts, |
| 95 | app->timeouts_size); |
| 96 | if (!inc->timeout_table) { |
| 97 | ret = -ENOMEM; |
| 98 | goto out; |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | ret = pp->register_app(inc); |
| 103 | if (ret) |
| 104 | goto out; |
| 105 | |
| 106 | list_add(&inc->a_list, &app->incs_list); |
| 107 | IP_VS_DBG(9, "%s application %s:%u registered\n", |
| 108 | pp->name, inc->name, inc->port); |
| 109 | |
| 110 | return 0; |
| 111 | |
| 112 | out: |
Jesper Juhl | a51482b | 2005-11-08 09:41:34 -0800 | [diff] [blame^] | 113 | kfree(inc->timeout_table); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 114 | kfree(inc); |
| 115 | return ret; |
| 116 | } |
| 117 | |
| 118 | |
| 119 | /* |
| 120 | * Release app incarnation |
| 121 | */ |
| 122 | static void |
| 123 | ip_vs_app_inc_release(struct ip_vs_app *inc) |
| 124 | { |
| 125 | struct ip_vs_protocol *pp; |
| 126 | |
| 127 | if (!(pp = ip_vs_proto_get(inc->protocol))) |
| 128 | return; |
| 129 | |
| 130 | if (pp->unregister_app) |
| 131 | pp->unregister_app(inc); |
| 132 | |
| 133 | IP_VS_DBG(9, "%s App %s:%u unregistered\n", |
| 134 | pp->name, inc->name, inc->port); |
| 135 | |
| 136 | list_del(&inc->a_list); |
| 137 | |
Jesper Juhl | a51482b | 2005-11-08 09:41:34 -0800 | [diff] [blame^] | 138 | kfree(inc->timeout_table); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 139 | kfree(inc); |
| 140 | } |
| 141 | |
| 142 | |
| 143 | /* |
| 144 | * Get reference to app inc (only called from softirq) |
| 145 | * |
| 146 | */ |
| 147 | int ip_vs_app_inc_get(struct ip_vs_app *inc) |
| 148 | { |
| 149 | int result; |
| 150 | |
| 151 | atomic_inc(&inc->usecnt); |
| 152 | if (unlikely((result = ip_vs_app_get(inc->app)) != 1)) |
| 153 | atomic_dec(&inc->usecnt); |
| 154 | return result; |
| 155 | } |
| 156 | |
| 157 | |
| 158 | /* |
| 159 | * Put the app inc (only called from timer or net softirq) |
| 160 | */ |
| 161 | void ip_vs_app_inc_put(struct ip_vs_app *inc) |
| 162 | { |
| 163 | ip_vs_app_put(inc->app); |
| 164 | atomic_dec(&inc->usecnt); |
| 165 | } |
| 166 | |
| 167 | |
| 168 | /* |
| 169 | * Register an application incarnation in protocol applications |
| 170 | */ |
| 171 | int |
| 172 | register_ip_vs_app_inc(struct ip_vs_app *app, __u16 proto, __u16 port) |
| 173 | { |
| 174 | int result; |
| 175 | |
| 176 | down(&__ip_vs_app_mutex); |
| 177 | |
| 178 | result = ip_vs_app_inc_new(app, proto, port); |
| 179 | |
| 180 | up(&__ip_vs_app_mutex); |
| 181 | |
| 182 | return result; |
| 183 | } |
| 184 | |
| 185 | |
| 186 | /* |
| 187 | * ip_vs_app registration routine |
| 188 | */ |
| 189 | int register_ip_vs_app(struct ip_vs_app *app) |
| 190 | { |
| 191 | /* increase the module use count */ |
| 192 | ip_vs_use_count_inc(); |
| 193 | |
| 194 | down(&__ip_vs_app_mutex); |
| 195 | |
| 196 | list_add(&app->a_list, &ip_vs_app_list); |
| 197 | |
| 198 | up(&__ip_vs_app_mutex); |
| 199 | |
| 200 | return 0; |
| 201 | } |
| 202 | |
| 203 | |
| 204 | /* |
| 205 | * ip_vs_app unregistration routine |
| 206 | * We are sure there are no app incarnations attached to services |
| 207 | */ |
| 208 | void unregister_ip_vs_app(struct ip_vs_app *app) |
| 209 | { |
| 210 | struct ip_vs_app *inc, *nxt; |
| 211 | |
| 212 | down(&__ip_vs_app_mutex); |
| 213 | |
| 214 | list_for_each_entry_safe(inc, nxt, &app->incs_list, a_list) { |
| 215 | ip_vs_app_inc_release(inc); |
| 216 | } |
| 217 | |
| 218 | list_del(&app->a_list); |
| 219 | |
| 220 | up(&__ip_vs_app_mutex); |
| 221 | |
| 222 | /* decrease the module use count */ |
| 223 | ip_vs_use_count_dec(); |
| 224 | } |
| 225 | |
| 226 | |
| 227 | #if 0000 |
| 228 | /* |
| 229 | * Get reference to app by name (called from user context) |
| 230 | */ |
| 231 | struct ip_vs_app *ip_vs_app_get_by_name(char *appname) |
| 232 | { |
| 233 | struct ip_vs_app *app, *a = NULL; |
| 234 | |
| 235 | down(&__ip_vs_app_mutex); |
| 236 | |
| 237 | list_for_each_entry(ent, &ip_vs_app_list, a_list) { |
| 238 | if (strcmp(app->name, appname)) |
| 239 | continue; |
| 240 | |
| 241 | /* softirq may call ip_vs_app_get too, so the caller |
| 242 | must disable softirq on the current CPU */ |
| 243 | if (ip_vs_app_get(app)) |
| 244 | a = app; |
| 245 | break; |
| 246 | } |
| 247 | |
| 248 | up(&__ip_vs_app_mutex); |
| 249 | |
| 250 | return a; |
| 251 | } |
| 252 | #endif |
| 253 | |
| 254 | |
| 255 | /* |
| 256 | * Bind ip_vs_conn to its ip_vs_app (called by cp constructor) |
| 257 | */ |
| 258 | int ip_vs_bind_app(struct ip_vs_conn *cp, struct ip_vs_protocol *pp) |
| 259 | { |
| 260 | return pp->app_conn_bind(cp); |
| 261 | } |
| 262 | |
| 263 | |
| 264 | /* |
| 265 | * Unbind cp from application incarnation (called by cp destructor) |
| 266 | */ |
| 267 | void ip_vs_unbind_app(struct ip_vs_conn *cp) |
| 268 | { |
| 269 | struct ip_vs_app *inc = cp->app; |
| 270 | |
| 271 | if (!inc) |
| 272 | return; |
| 273 | |
| 274 | if (inc->unbind_conn) |
| 275 | inc->unbind_conn(inc, cp); |
| 276 | if (inc->done_conn) |
| 277 | inc->done_conn(inc, cp); |
| 278 | ip_vs_app_inc_put(inc); |
| 279 | cp->app = NULL; |
| 280 | } |
| 281 | |
| 282 | |
| 283 | /* |
| 284 | * Fixes th->seq based on ip_vs_seq info. |
| 285 | */ |
| 286 | static inline void vs_fix_seq(const struct ip_vs_seq *vseq, struct tcphdr *th) |
| 287 | { |
| 288 | __u32 seq = ntohl(th->seq); |
| 289 | |
| 290 | /* |
| 291 | * Adjust seq with delta-offset for all packets after |
| 292 | * the most recent resized pkt seq and with previous_delta offset |
| 293 | * for all packets before most recent resized pkt seq. |
| 294 | */ |
| 295 | if (vseq->delta || vseq->previous_delta) { |
| 296 | if(after(seq, vseq->init_seq)) { |
| 297 | th->seq = htonl(seq + vseq->delta); |
| 298 | IP_VS_DBG(9, "vs_fix_seq(): added delta (%d) to seq\n", |
| 299 | vseq->delta); |
| 300 | } else { |
| 301 | th->seq = htonl(seq + vseq->previous_delta); |
| 302 | IP_VS_DBG(9, "vs_fix_seq(): added previous_delta " |
| 303 | "(%d) to seq\n", vseq->previous_delta); |
| 304 | } |
| 305 | } |
| 306 | } |
| 307 | |
| 308 | |
| 309 | /* |
| 310 | * Fixes th->ack_seq based on ip_vs_seq info. |
| 311 | */ |
| 312 | static inline void |
| 313 | vs_fix_ack_seq(const struct ip_vs_seq *vseq, struct tcphdr *th) |
| 314 | { |
| 315 | __u32 ack_seq = ntohl(th->ack_seq); |
| 316 | |
| 317 | /* |
| 318 | * Adjust ack_seq with delta-offset for |
| 319 | * the packets AFTER most recent resized pkt has caused a shift |
| 320 | * for packets before most recent resized pkt, use previous_delta |
| 321 | */ |
| 322 | if (vseq->delta || vseq->previous_delta) { |
| 323 | /* since ack_seq is the number of octet that is expected |
| 324 | to receive next, so compare it with init_seq+delta */ |
| 325 | if(after(ack_seq, vseq->init_seq+vseq->delta)) { |
| 326 | th->ack_seq = htonl(ack_seq - vseq->delta); |
| 327 | IP_VS_DBG(9, "vs_fix_ack_seq(): subtracted delta " |
| 328 | "(%d) from ack_seq\n", vseq->delta); |
| 329 | |
| 330 | } else { |
| 331 | th->ack_seq = htonl(ack_seq - vseq->previous_delta); |
| 332 | IP_VS_DBG(9, "vs_fix_ack_seq(): subtracted " |
| 333 | "previous_delta (%d) from ack_seq\n", |
| 334 | vseq->previous_delta); |
| 335 | } |
| 336 | } |
| 337 | } |
| 338 | |
| 339 | |
| 340 | /* |
| 341 | * Updates ip_vs_seq if pkt has been resized |
| 342 | * Assumes already checked proto==IPPROTO_TCP and diff!=0. |
| 343 | */ |
| 344 | static inline void vs_seq_update(struct ip_vs_conn *cp, struct ip_vs_seq *vseq, |
| 345 | unsigned flag, __u32 seq, int diff) |
| 346 | { |
| 347 | /* spinlock is to keep updating cp->flags atomic */ |
| 348 | spin_lock(&cp->lock); |
| 349 | if (!(cp->flags & flag) || after(seq, vseq->init_seq)) { |
| 350 | vseq->previous_delta = vseq->delta; |
| 351 | vseq->delta += diff; |
| 352 | vseq->init_seq = seq; |
| 353 | cp->flags |= flag; |
| 354 | } |
| 355 | spin_unlock(&cp->lock); |
| 356 | } |
| 357 | |
| 358 | static inline int app_tcp_pkt_out(struct ip_vs_conn *cp, struct sk_buff **pskb, |
| 359 | struct ip_vs_app *app) |
| 360 | { |
| 361 | int diff; |
| 362 | unsigned int tcp_offset = (*pskb)->nh.iph->ihl*4; |
| 363 | struct tcphdr *th; |
| 364 | __u32 seq; |
| 365 | |
| 366 | if (!ip_vs_make_skb_writable(pskb, tcp_offset + sizeof(*th))) |
| 367 | return 0; |
| 368 | |
| 369 | th = (struct tcphdr *)((*pskb)->nh.raw + tcp_offset); |
| 370 | |
| 371 | /* |
| 372 | * Remember seq number in case this pkt gets resized |
| 373 | */ |
| 374 | seq = ntohl(th->seq); |
| 375 | |
| 376 | /* |
| 377 | * Fix seq stuff if flagged as so. |
| 378 | */ |
| 379 | if (cp->flags & IP_VS_CONN_F_OUT_SEQ) |
| 380 | vs_fix_seq(&cp->out_seq, th); |
| 381 | if (cp->flags & IP_VS_CONN_F_IN_SEQ) |
| 382 | vs_fix_ack_seq(&cp->in_seq, th); |
| 383 | |
| 384 | /* |
| 385 | * Call private output hook function |
| 386 | */ |
| 387 | if (app->pkt_out == NULL) |
| 388 | return 1; |
| 389 | |
| 390 | if (!app->pkt_out(app, cp, pskb, &diff)) |
| 391 | return 0; |
| 392 | |
| 393 | /* |
| 394 | * Update ip_vs seq stuff if len has changed. |
| 395 | */ |
| 396 | if (diff != 0) |
| 397 | vs_seq_update(cp, &cp->out_seq, |
| 398 | IP_VS_CONN_F_OUT_SEQ, seq, diff); |
| 399 | |
| 400 | return 1; |
| 401 | } |
| 402 | |
| 403 | /* |
| 404 | * Output pkt hook. Will call bound ip_vs_app specific function |
| 405 | * called by ipvs packet handler, assumes previously checked cp!=NULL |
| 406 | * returns false if it can't handle packet (oom) |
| 407 | */ |
| 408 | int ip_vs_app_pkt_out(struct ip_vs_conn *cp, struct sk_buff **pskb) |
| 409 | { |
| 410 | struct ip_vs_app *app; |
| 411 | |
| 412 | /* |
| 413 | * check if application module is bound to |
| 414 | * this ip_vs_conn. |
| 415 | */ |
| 416 | if ((app = cp->app) == NULL) |
| 417 | return 1; |
| 418 | |
| 419 | /* TCP is complicated */ |
| 420 | if (cp->protocol == IPPROTO_TCP) |
| 421 | return app_tcp_pkt_out(cp, pskb, app); |
| 422 | |
| 423 | /* |
| 424 | * Call private output hook function |
| 425 | */ |
| 426 | if (app->pkt_out == NULL) |
| 427 | return 1; |
| 428 | |
| 429 | return app->pkt_out(app, cp, pskb, NULL); |
| 430 | } |
| 431 | |
| 432 | |
| 433 | static inline int app_tcp_pkt_in(struct ip_vs_conn *cp, struct sk_buff **pskb, |
| 434 | struct ip_vs_app *app) |
| 435 | { |
| 436 | int diff; |
| 437 | unsigned int tcp_offset = (*pskb)->nh.iph->ihl*4; |
| 438 | struct tcphdr *th; |
| 439 | __u32 seq; |
| 440 | |
| 441 | if (!ip_vs_make_skb_writable(pskb, tcp_offset + sizeof(*th))) |
| 442 | return 0; |
| 443 | |
| 444 | th = (struct tcphdr *)((*pskb)->nh.raw + tcp_offset); |
| 445 | |
| 446 | /* |
| 447 | * Remember seq number in case this pkt gets resized |
| 448 | */ |
| 449 | seq = ntohl(th->seq); |
| 450 | |
| 451 | /* |
| 452 | * Fix seq stuff if flagged as so. |
| 453 | */ |
| 454 | if (cp->flags & IP_VS_CONN_F_IN_SEQ) |
| 455 | vs_fix_seq(&cp->in_seq, th); |
| 456 | if (cp->flags & IP_VS_CONN_F_OUT_SEQ) |
| 457 | vs_fix_ack_seq(&cp->out_seq, th); |
| 458 | |
| 459 | /* |
| 460 | * Call private input hook function |
| 461 | */ |
| 462 | if (app->pkt_in == NULL) |
| 463 | return 1; |
| 464 | |
| 465 | if (!app->pkt_in(app, cp, pskb, &diff)) |
| 466 | return 0; |
| 467 | |
| 468 | /* |
| 469 | * Update ip_vs seq stuff if len has changed. |
| 470 | */ |
| 471 | if (diff != 0) |
| 472 | vs_seq_update(cp, &cp->in_seq, |
| 473 | IP_VS_CONN_F_IN_SEQ, seq, diff); |
| 474 | |
| 475 | return 1; |
| 476 | } |
| 477 | |
| 478 | /* |
| 479 | * Input pkt hook. Will call bound ip_vs_app specific function |
| 480 | * called by ipvs packet handler, assumes previously checked cp!=NULL. |
| 481 | * returns false if can't handle packet (oom). |
| 482 | */ |
| 483 | int ip_vs_app_pkt_in(struct ip_vs_conn *cp, struct sk_buff **pskb) |
| 484 | { |
| 485 | struct ip_vs_app *app; |
| 486 | |
| 487 | /* |
| 488 | * check if application module is bound to |
| 489 | * this ip_vs_conn. |
| 490 | */ |
| 491 | if ((app = cp->app) == NULL) |
| 492 | return 1; |
| 493 | |
| 494 | /* TCP is complicated */ |
| 495 | if (cp->protocol == IPPROTO_TCP) |
| 496 | return app_tcp_pkt_in(cp, pskb, app); |
| 497 | |
| 498 | /* |
| 499 | * Call private input hook function |
| 500 | */ |
| 501 | if (app->pkt_in == NULL) |
| 502 | return 1; |
| 503 | |
| 504 | return app->pkt_in(app, cp, pskb, NULL); |
| 505 | } |
| 506 | |
| 507 | |
| 508 | #ifdef CONFIG_PROC_FS |
| 509 | /* |
| 510 | * /proc/net/ip_vs_app entry function |
| 511 | */ |
| 512 | |
| 513 | static struct ip_vs_app *ip_vs_app_idx(loff_t pos) |
| 514 | { |
| 515 | struct ip_vs_app *app, *inc; |
| 516 | |
| 517 | list_for_each_entry(app, &ip_vs_app_list, a_list) { |
| 518 | list_for_each_entry(inc, &app->incs_list, a_list) { |
| 519 | if (pos-- == 0) |
| 520 | return inc; |
| 521 | } |
| 522 | } |
| 523 | return NULL; |
| 524 | |
| 525 | } |
| 526 | |
| 527 | static void *ip_vs_app_seq_start(struct seq_file *seq, loff_t *pos) |
| 528 | { |
| 529 | down(&__ip_vs_app_mutex); |
| 530 | |
| 531 | return *pos ? ip_vs_app_idx(*pos - 1) : SEQ_START_TOKEN; |
| 532 | } |
| 533 | |
| 534 | static void *ip_vs_app_seq_next(struct seq_file *seq, void *v, loff_t *pos) |
| 535 | { |
| 536 | struct ip_vs_app *inc, *app; |
| 537 | struct list_head *e; |
| 538 | |
| 539 | ++*pos; |
| 540 | if (v == SEQ_START_TOKEN) |
| 541 | return ip_vs_app_idx(0); |
| 542 | |
| 543 | inc = v; |
| 544 | app = inc->app; |
| 545 | |
| 546 | if ((e = inc->a_list.next) != &app->incs_list) |
| 547 | return list_entry(e, struct ip_vs_app, a_list); |
| 548 | |
| 549 | /* go on to next application */ |
| 550 | for (e = app->a_list.next; e != &ip_vs_app_list; e = e->next) { |
| 551 | app = list_entry(e, struct ip_vs_app, a_list); |
| 552 | list_for_each_entry(inc, &app->incs_list, a_list) { |
| 553 | return inc; |
| 554 | } |
| 555 | } |
| 556 | return NULL; |
| 557 | } |
| 558 | |
| 559 | static void ip_vs_app_seq_stop(struct seq_file *seq, void *v) |
| 560 | { |
| 561 | up(&__ip_vs_app_mutex); |
| 562 | } |
| 563 | |
| 564 | static int ip_vs_app_seq_show(struct seq_file *seq, void *v) |
| 565 | { |
| 566 | if (v == SEQ_START_TOKEN) |
| 567 | seq_puts(seq, "prot port usecnt name\n"); |
| 568 | else { |
| 569 | const struct ip_vs_app *inc = v; |
| 570 | |
| 571 | seq_printf(seq, "%-3s %-7u %-6d %-17s\n", |
| 572 | ip_vs_proto_name(inc->protocol), |
| 573 | ntohs(inc->port), |
| 574 | atomic_read(&inc->usecnt), |
| 575 | inc->name); |
| 576 | } |
| 577 | return 0; |
| 578 | } |
| 579 | |
| 580 | static struct seq_operations ip_vs_app_seq_ops = { |
| 581 | .start = ip_vs_app_seq_start, |
| 582 | .next = ip_vs_app_seq_next, |
| 583 | .stop = ip_vs_app_seq_stop, |
| 584 | .show = ip_vs_app_seq_show, |
| 585 | }; |
| 586 | |
| 587 | static int ip_vs_app_open(struct inode *inode, struct file *file) |
| 588 | { |
| 589 | return seq_open(file, &ip_vs_app_seq_ops); |
| 590 | } |
| 591 | |
| 592 | static struct file_operations ip_vs_app_fops = { |
| 593 | .owner = THIS_MODULE, |
| 594 | .open = ip_vs_app_open, |
| 595 | .read = seq_read, |
| 596 | .llseek = seq_lseek, |
| 597 | .release = seq_release, |
| 598 | }; |
| 599 | #endif |
| 600 | |
| 601 | |
| 602 | /* |
| 603 | * Replace a segment of data with a new segment |
| 604 | */ |
Al Viro | dd0fc66 | 2005-10-07 07:46:04 +0100 | [diff] [blame] | 605 | int ip_vs_skb_replace(struct sk_buff *skb, gfp_t pri, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 606 | char *o_buf, int o_len, char *n_buf, int n_len) |
| 607 | { |
| 608 | struct iphdr *iph; |
| 609 | int diff; |
| 610 | int o_offset; |
| 611 | int o_left; |
| 612 | |
| 613 | EnterFunction(9); |
| 614 | |
| 615 | diff = n_len - o_len; |
| 616 | o_offset = o_buf - (char *)skb->data; |
| 617 | /* The length of left data after o_buf+o_len in the skb data */ |
| 618 | o_left = skb->len - (o_offset + o_len); |
| 619 | |
| 620 | if (diff <= 0) { |
| 621 | memmove(o_buf + n_len, o_buf + o_len, o_left); |
| 622 | memcpy(o_buf, n_buf, n_len); |
| 623 | skb_trim(skb, skb->len + diff); |
| 624 | } else if (diff <= skb_tailroom(skb)) { |
| 625 | skb_put(skb, diff); |
| 626 | memmove(o_buf + n_len, o_buf + o_len, o_left); |
| 627 | memcpy(o_buf, n_buf, n_len); |
| 628 | } else { |
| 629 | if (pskb_expand_head(skb, skb_headroom(skb), diff, pri)) |
| 630 | return -ENOMEM; |
| 631 | skb_put(skb, diff); |
| 632 | memmove(skb->data + o_offset + n_len, |
| 633 | skb->data + o_offset + o_len, o_left); |
| 634 | memcpy(skb->data + o_offset, n_buf, n_len); |
| 635 | } |
| 636 | |
| 637 | /* must update the iph total length here */ |
| 638 | iph = skb->nh.iph; |
| 639 | iph->tot_len = htons(skb->len); |
| 640 | |
| 641 | LeaveFunction(9); |
| 642 | return 0; |
| 643 | } |
| 644 | |
| 645 | |
| 646 | int ip_vs_app_init(void) |
| 647 | { |
| 648 | /* we will replace it with proc_net_ipvs_create() soon */ |
| 649 | proc_net_fops_create("ip_vs_app", 0, &ip_vs_app_fops); |
| 650 | return 0; |
| 651 | } |
| 652 | |
| 653 | |
| 654 | void ip_vs_app_cleanup(void) |
| 655 | { |
| 656 | proc_net_remove("ip_vs_app"); |
| 657 | } |