1 /* 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD: src/sys/netinet/ip_divert.c,v 1.42.2.6 2003/01/23 21:06:45 sam Exp $ 30 */ 31 32 #define _IP_VHL 33 34 #include "opt_inet.h" 35 #include "opt_ipdivert.h" 36 37 #ifndef INET 38 #error "IPDIVERT requires INET." 39 #endif 40 41 #include <sys/param.h> 42 #include <sys/kernel.h> 43 #include <sys/malloc.h> 44 #include <sys/mbuf.h> 45 #include <sys/socket.h> 46 #include <sys/protosw.h> 47 #include <sys/socketvar.h> 48 #include <sys/socketvar2.h> 49 #include <sys/sysctl.h> 50 #include <sys/systm.h> 51 #include <sys/proc.h> 52 #include <sys/priv.h> 53 #include <sys/in_cksum.h> 54 #include <sys/lock.h> 55 #include <sys/msgport.h> 56 57 #include <net/if.h> 58 #include <net/route.h> 59 60 #include <net/netmsg2.h> 61 #include <net/netisr2.h> 62 63 #include <netinet/in.h> 64 #include <netinet/in_systm.h> 65 #include <netinet/ip.h> 66 #include <netinet/in_pcb.h> 67 #include <netinet/in_var.h> 68 #include <netinet/ip_var.h> 69 #include <netinet/ip_divert.h> 70 71 /* 72 * Divert sockets 73 */ 74 75 /* 76 * Allocate enough space to hold a full IP packet 77 */ 78 #define DIVSNDQ (65536 + 100) 79 #define DIVRCVQ (65536 + 100) 80 81 #define DIV_IS_OUTPUT(sin) ((sin) == NULL || (sin)->sin_addr.s_addr == 0) 82 83 #define DIV_OUTPUT 0x10000 84 #define DIV_INPUT 0x20000 85 86 /* 87 * Divert sockets work in conjunction with ipfw, see the divert(4) 88 * manpage for features. 89 * Internally, packets selected by ipfw in ip_input() or ip_output(), 90 * and never diverted before, are passed to the input queue of the 91 * divert socket with a given 'divert_port' number (as specified in 92 * the matching ipfw rule), and they are tagged with a 16 bit cookie 93 * (representing the rule number of the matching ipfw rule), which 94 * is passed to process reading from the socket. 95 * 96 * Packets written to the divert socket are again tagged with a cookie 97 * (usually the same as above) and a destination address. 98 * If the destination address is INADDR_ANY then the packet is 99 * treated as outgoing and sent to ip_output(), otherwise it is 100 * treated as incoming and sent to ip_input(). 101 * In both cases, the packet is tagged with the cookie. 102 * 103 * On reinjection, processing in ip_input() and ip_output() 104 * will be exactly the same as for the original packet, except that 105 * ipfw processing will start at the rule number after the one 106 * written in the cookie (so, tagging a packet with a cookie of 0 107 * will cause it to be effectively considered as a standard packet). 108 */ 109 110 /* Internal variables */ 111 static struct inpcbinfo divcbinfo; 112 static struct inpcbportinfo divcbportinfo; 113 114 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 115 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 116 117 static struct mbuf *ip_divert(struct mbuf *, int, int); 118 119 /* 120 * Initialize divert connection block queue. 121 */ 122 void 123 div_init(void) 124 { 125 in_pcbinfo_init(&divcbinfo, 0, FALSE); 126 in_pcbportinfo_init(&divcbportinfo, 1, 0); 127 /* 128 * XXX We don't use the hash list for divert IP, but it's easier 129 * to allocate a one entry hash list than it is to check all 130 * over the place for hashbase == NULL. 131 */ 132 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); 133 in_pcbportinfo_set(&divcbinfo, &divcbportinfo, 1); 134 divcbinfo.wildcardhashbase = hashinit(1, M_PCB, 135 &divcbinfo.wildcardhashmask); 136 divcbinfo.ipi_size = sizeof(struct inpcb); 137 ip_divert_p = ip_divert; 138 } 139 140 /* 141 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets 142 * with that protocol number to enter the system from the outside. 143 */ 144 int 145 div_input(struct mbuf **mp, int *offp, int proto) 146 { 147 struct mbuf *m = *mp; 148 149 ipstat.ips_noproto++; 150 m_freem(m); 151 return(IPPROTO_DONE); 152 } 153 154 /* 155 * Divert a packet by passing it up to the divert socket at port 'port'. 156 * 157 * Setup generic address and protocol structures for div_input routine, 158 * then pass them along with mbuf chain. 159 */ 160 static void 161 div_packet(struct mbuf *m, int incoming, int port) 162 { 163 struct sockaddr_in divsrc = { sizeof divsrc, AF_INET }; 164 struct inpcb *inp; 165 struct socket *sa; 166 struct m_tag *mtag; 167 struct divert_info *divinfo; 168 u_int16_t nport; 169 170 ASSERT_NETISR0; 171 172 /* Locate the divert info */ 173 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 174 divinfo = m_tag_data(mtag); 175 divsrc.sin_port = divinfo->skipto; 176 177 /* 178 * Record receive interface address, if any. 179 * But only for incoming packets. 180 */ 181 divsrc.sin_addr.s_addr = 0; 182 if (incoming) { 183 struct ifaddr_container *ifac; 184 185 /* Find IP address for receive interface */ 186 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 187 ifa_link) { 188 struct ifaddr *ifa = ifac->ifa; 189 190 if (ifa->ifa_addr == NULL) 191 continue; 192 if (ifa->ifa_addr->sa_family != AF_INET) 193 continue; 194 divsrc.sin_addr = 195 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 196 break; 197 } 198 } 199 /* 200 * Record the incoming interface name whenever we have one. 201 */ 202 if (m->m_pkthdr.rcvif) { 203 /* 204 * Hide the actual interface name in there in the 205 * sin_zero array. XXX This needs to be moved to a 206 * different sockaddr type for divert, e.g. 207 * sockaddr_div with multiple fields like 208 * sockaddr_dl. Presently we have only 7 bytes 209 * but that will do for now as most interfaces 210 * are 4 or less + 2 or less bytes for unit. 211 * There is probably a faster way of doing this, 212 * possibly taking it from the sockaddr_dl on the iface. 213 * This solves the problem of a P2P link and a LAN interface 214 * having the same address, which can result in the wrong 215 * interface being assigned to the packet when fed back 216 * into the divert socket. Theoretically if the daemon saves 217 * and re-uses the sockaddr_in as suggested in the man pages, 218 * this iface name will come along for the ride. 219 * (see div_output for the other half of this.) 220 */ 221 ksnprintf(divsrc.sin_zero, sizeof divsrc.sin_zero, "%s", 222 m->m_pkthdr.rcvif->if_xname); 223 } 224 225 /* Put packet on socket queue, if any */ 226 sa = NULL; 227 nport = htons((u_int16_t)port); 228 229 /* 230 * Following loop to locate the inpcb is MPSAFE since the inpcb 231 * insertion/removal happens on the same CPU (CPU0). 232 */ 233 LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) { 234 if (inp->inp_flags & INP_PLACEMARKER) 235 continue; 236 if (inp->inp_lport == nport) 237 sa = inp->inp_socket; 238 } 239 if (sa) { 240 lwkt_gettoken(&sa->so_rcv.ssb_token); 241 if (ssb_appendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, NULL) == 0) { 242 m_freem(m); 243 soroverflow(sa); 244 } else 245 sorwakeup(sa); 246 lwkt_reltoken(&sa->so_rcv.ssb_token); 247 } else { 248 m_freem(m); 249 ipstat.ips_noproto++; 250 ipstat.ips_delivered--; 251 } 252 } 253 254 static void 255 div_packet_handler(netmsg_t msg) 256 { 257 struct mbuf *m; 258 int port, incoming = 0; 259 260 m = msg->packet.nm_packet; 261 262 port = msg->lmsg.u.ms_result32 & 0xffff; 263 if (msg->lmsg.u.ms_result32 & DIV_INPUT) 264 incoming = 1; 265 div_packet(m, incoming, port); 266 /* no reply, msg embedded in mbuf */ 267 } 268 269 static void 270 divert_packet(struct mbuf *m, int incoming) 271 { 272 struct m_tag *mtag; 273 struct divert_info *divinfo; 274 int port; 275 276 M_ASSERTPKTHDR(m); 277 278 /* Assure header */ 279 if (m->m_len < sizeof(struct ip) && 280 (m = m_pullup(m, sizeof(struct ip))) == NULL) 281 return; 282 283 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 284 KASSERT(mtag != NULL, ("%s no divert tag!", __func__)); 285 divinfo = m_tag_data(mtag); 286 287 port = divinfo->port; 288 KASSERT(port != 0, ("%s: port=0", __func__)); 289 290 if (mycpuid != 0) { 291 struct netmsg_packet *nmp; 292 293 nmp = &m->m_hdr.mh_netmsg; 294 netmsg_init(&nmp->base, NULL, &netisr_apanic_rport, 295 0, div_packet_handler); 296 nmp->nm_packet = m; 297 298 nmp->base.lmsg.u.ms_result32 = port; /* port is 16bits */ 299 if (incoming) 300 nmp->base.lmsg.u.ms_result32 |= DIV_INPUT; 301 else 302 nmp->base.lmsg.u.ms_result32 |= DIV_OUTPUT; 303 304 lwkt_sendmsg(netisr_cpuport(0), &nmp->base.lmsg); 305 } else { 306 div_packet(m, incoming, port); 307 } 308 } 309 310 /* 311 * Deliver packet back into the IP processing machinery. 312 * 313 * If no address specified, or address is 0.0.0.0, send to ip_output(); 314 * otherwise, send to ip_input() and mark as having been received on 315 * the interface with that address. 316 */ 317 static int 318 div_output(struct socket *so, struct mbuf *m, 319 struct sockaddr_in *sin, struct mbuf *control) 320 { 321 int error = 0; 322 struct m_tag *mtag; 323 struct divert_info *divinfo; 324 325 ASSERT_NETISR0; 326 327 if (control) 328 m_freem(control); /* XXX */ 329 330 /* 331 * Prepare the tag for divert info. Note that a packet 332 * with a 0 tag in mh_data is effectively untagged, 333 * so we could optimize that case. 334 */ 335 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(*divinfo), M_NOWAIT); 336 if (mtag == NULL) { 337 error = ENOBUFS; 338 goto cantsend; 339 } 340 m_tag_prepend(m, mtag); 341 342 /* Loopback avoidance and state recovery */ 343 divinfo = m_tag_data(mtag); 344 if (sin) 345 divinfo->skipto = sin->sin_port; 346 else 347 divinfo->skipto = 0; 348 349 /* Reinject packet into the system as incoming or outgoing */ 350 if (DIV_IS_OUTPUT(sin)) { 351 struct ip *const ip = mtod(m, struct ip *); 352 353 /* Don't allow packet length sizes that will crash */ 354 if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) { 355 error = EINVAL; 356 goto cantsend; 357 } 358 359 /* Send packet to output processing */ 360 ipstat.ips_rawout++; /* XXX */ 361 error = ip_output(m, NULL, NULL, 362 (so->so_options & SO_DONTROUTE) | 363 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 364 NULL, NULL); 365 } else { 366 ip_input(m); 367 } 368 return error; 369 370 cantsend: 371 m_freem(m); 372 return error; 373 } 374 375 static void 376 div_attach(netmsg_t msg) 377 { 378 struct socket *so = msg->attach.base.nm_so; 379 int proto = msg->attach.nm_proto; 380 struct pru_attach_info *ai = msg->attach.nm_ai; 381 struct inpcb *inp; 382 int error; 383 384 ASSERT_NETISR0; 385 386 inp = so->so_pcb; 387 if (inp) 388 panic("div_attach"); 389 error = priv_check_cred(ai->p_ucred, PRIV_ROOT, NULL_CRED_OKAY); 390 if (error) 391 goto out; 392 393 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit); 394 if (error) 395 goto out; 396 error = in_pcballoc(so, &divcbinfo); 397 if (error) 398 goto out; 399 inp = (struct inpcb *)so->so_pcb; 400 inp->inp_ip_p = proto; 401 inp->inp_flags |= INP_HDRINCL; 402 /* 403 * The socket is always "connected" because 404 * we always know "where" to send the packet. 405 */ 406 sosetstate(so, SS_ISCONNECTED); 407 error = 0; 408 out: 409 lwkt_replymsg(&msg->attach.base.lmsg, error); 410 } 411 412 static void 413 div_detach(netmsg_t msg) 414 { 415 struct socket *so = msg->detach.base.nm_so; 416 struct inpcb *inp; 417 418 ASSERT_NETISR0; 419 420 inp = so->so_pcb; 421 if (inp == NULL) 422 panic("div_detach"); 423 in_pcbdetach(inp); 424 lwkt_replymsg(&msg->detach.base.lmsg, 0); 425 } 426 427 static void 428 div_abort(netmsg_t msg) 429 { 430 /* 431 * Divert socket does not support listen(2), 432 * so this should never be called. 433 */ 434 panic("div_abort is called"); 435 } 436 437 static void 438 div_disconnect(netmsg_t msg) 439 { 440 struct socket *so = msg->disconnect.base.nm_so; 441 int error; 442 443 ASSERT_NETISR0; 444 445 if (so->so_state & SS_ISCONNECTED) { 446 soisdisconnected(so); 447 error = 0; 448 } else { 449 error = ENOTCONN; 450 } 451 lwkt_replymsg(&msg->disconnect.base.lmsg, error); 452 } 453 454 static void 455 div_bind(netmsg_t msg) 456 { 457 struct socket *so = msg->bind.base.nm_so; 458 struct sockaddr *nam = msg->bind.nm_nam; 459 int error; 460 461 ASSERT_NETISR0; 462 463 /* 464 * in_pcbbind assumes that nam is a sockaddr_in 465 * and in_pcbbind requires a valid address. Since divert 466 * sockets don't we need to make sure the address is 467 * filled in properly. 468 * XXX -- divert should not be abusing in_pcbind 469 * and should probably have its own family. 470 */ 471 if (nam->sa_family != AF_INET) { 472 error = EAFNOSUPPORT; 473 } else { 474 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 475 error = in_pcbbind(so->so_pcb, nam, msg->bind.nm_td); 476 } 477 lwkt_replymsg(&msg->bind.base.lmsg, error); 478 } 479 480 static void 481 div_shutdown(netmsg_t msg) 482 { 483 struct socket *so = msg->shutdown.base.nm_so; 484 485 ASSERT_NETISR0; 486 487 socantsendmore(so); 488 489 lwkt_replymsg(&msg->shutdown.base.lmsg, 0); 490 } 491 492 static void 493 div_send(netmsg_t msg) 494 { 495 struct socket *so = msg->send.base.nm_so; 496 struct mbuf *m = msg->send.nm_m; 497 struct sockaddr *nam = msg->send.nm_addr; 498 struct mbuf *control = msg->send.nm_control; 499 int error; 500 501 /* Length check already done in ip_hashfn() */ 502 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf")); 503 504 /* Send packet */ 505 error = div_output(so, m, (struct sockaddr_in *)nam, control); 506 lwkt_replymsg(&msg->send.base.lmsg, error); 507 } 508 509 SYSCTL_DECL(_net_inet_divert); 510 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 1, 511 in_pcblist_range, "S,xinpcb", "List of active divert sockets"); 512 513 struct pr_usrreqs div_usrreqs = { 514 .pru_abort = div_abort, 515 .pru_accept = pr_generic_notsupp, 516 .pru_attach = div_attach, 517 .pru_bind = div_bind, 518 .pru_connect = pr_generic_notsupp, 519 .pru_connect2 = pr_generic_notsupp, 520 .pru_control = in_control_dispatch, 521 .pru_detach = div_detach, 522 .pru_disconnect = div_disconnect, 523 .pru_listen = pr_generic_notsupp, 524 .pru_peeraddr = in_setpeeraddr_dispatch, 525 .pru_rcvd = pr_generic_notsupp, 526 .pru_rcvoob = pr_generic_notsupp, 527 .pru_send = div_send, 528 .pru_sense = pru_sense_null, 529 .pru_shutdown = div_shutdown, 530 .pru_sockaddr = in_setsockaddr_dispatch, 531 .pru_sosend = sosend, 532 .pru_soreceive = soreceive 533 }; 534 535 static struct mbuf * 536 ip_divert_out(struct mbuf *m, int tee) 537 { 538 struct mbuf *clone = NULL; 539 struct ip *ip = mtod(m, struct ip *); 540 541 /* Clone packet if we're doing a 'tee' */ 542 if (tee) 543 clone = m_dup(m, M_NOWAIT); 544 545 /* 546 * XXX 547 * delayed checksums are not currently compatible 548 * with divert sockets. 549 */ 550 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 551 in_delayed_cksum(m); 552 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 553 } 554 555 /* Deliver packet to divert input routine */ 556 divert_packet(m, 0); 557 558 /* If 'tee', continue with original packet */ 559 return clone; 560 } 561 562 static struct mbuf * 563 ip_divert_in(struct mbuf *m, int tee) 564 { 565 struct mbuf *clone = NULL; 566 struct ip *ip = mtod(m, struct ip *); 567 struct m_tag *mtag; 568 569 if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) { 570 const struct divert_info *divinfo; 571 u_short frag_off; 572 int hlen; 573 574 /* 575 * Only trust divert info in the fragment 576 * at offset 0. 577 */ 578 frag_off = ntohs(ip->ip_off) << 3; 579 if (frag_off != 0) { 580 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 581 m_tag_delete(m, mtag); 582 } 583 584 /* 585 * Attempt reassembly; if it succeeds, proceed. 586 * ip_reass() will return a different mbuf. 587 */ 588 m = ip_reass(m); 589 if (m == NULL) 590 return NULL; 591 ip = mtod(m, struct ip *); 592 593 /* Caller need to redispatch the packet, if it is for us */ 594 m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH; 595 596 /* 597 * Get the header length of the reassembled 598 * packet 599 */ 600 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 601 602 /* 603 * Restore original checksum before diverting 604 * packet 605 */ 606 ip->ip_len = htons(ntohs(ip->ip_len) + hlen); 607 ip->ip_sum = 0; 608 if (hlen == sizeof(struct ip)) 609 ip->ip_sum = in_cksum_hdr(ip); 610 else 611 ip->ip_sum = in_cksum(m, hlen); 612 613 /* 614 * Only use the saved divert info 615 */ 616 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 617 if (mtag == NULL) { 618 /* Wrongly configured ipfw */ 619 kprintf("ip_input no divert info\n"); 620 m_freem(m); 621 return NULL; 622 } 623 divinfo = m_tag_data(mtag); 624 tee = divinfo->tee; 625 } 626 627 /* 628 * Divert or tee packet to the divert protocol if 629 * required. 630 */ 631 632 /* Clone packet if we're doing a 'tee' */ 633 if (tee) 634 clone = m_dup(m, M_NOWAIT); 635 636 /* Deliver packet to divert input routine */ 637 divert_packet(m, 1); 638 639 /* Catch invalid reference */ 640 m = NULL; 641 ip = NULL; 642 643 ipstat.ips_delivered++; 644 645 /* If 'tee', continue with original packet */ 646 if (clone != NULL) { 647 /* 648 * Complete processing of the packet. 649 * XXX Better safe than sorry, remove the DIVERT tag. 650 */ 651 mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL); 652 KKASSERT(mtag != NULL); 653 m_tag_delete(clone, mtag); 654 } 655 return clone; 656 } 657 658 static struct mbuf * 659 ip_divert(struct mbuf *m, int tee, int incoming) 660 { 661 struct mbuf *ret; 662 663 if (incoming) 664 ret = ip_divert_in(m, tee); 665 else 666 ret = ip_divert_out(m, tee); 667 return ret; 668 } 669