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 #include "opt_ipsec.h" 37 38 #ifndef INET 39 #error "IPDIVERT requires INET." 40 #endif 41 42 #include <sys/param.h> 43 #include <sys/kernel.h> 44 #include <sys/malloc.h> 45 #include <sys/mbuf.h> 46 #include <sys/socket.h> 47 #include <sys/protosw.h> 48 #include <sys/socketvar.h> 49 #include <sys/socketvar2.h> 50 #include <sys/sysctl.h> 51 #include <sys/systm.h> 52 #include <sys/proc.h> 53 #include <sys/priv.h> 54 #include <sys/in_cksum.h> 55 #include <sys/lock.h> 56 #include <sys/msgport.h> 57 58 #include <net/if.h> 59 #include <net/route.h> 60 61 #include <net/netmsg2.h> 62 #include <net/netisr2.h> 63 #include <sys/thread2.h> 64 #include <sys/mplock2.h> 65 66 #include <netinet/in.h> 67 #include <netinet/in_systm.h> 68 #include <netinet/ip.h> 69 #include <netinet/in_pcb.h> 70 #include <netinet/in_var.h> 71 #include <netinet/ip_var.h> 72 #include <netinet/ip_divert.h> 73 74 /* 75 * Divert sockets 76 */ 77 78 /* 79 * Allocate enough space to hold a full IP packet 80 */ 81 #define DIVSNDQ (65536 + 100) 82 #define DIVRCVQ (65536 + 100) 83 84 #define DIV_IS_OUTPUT(sin) ((sin) == NULL || (sin)->sin_addr.s_addr == 0) 85 86 #define DIV_OUTPUT 0x10000 87 #define DIV_INPUT 0x20000 88 89 /* 90 * Divert sockets work in conjunction with ipfw, see the divert(4) 91 * manpage for features. 92 * Internally, packets selected by ipfw in ip_input() or ip_output(), 93 * and never diverted before, are passed to the input queue of the 94 * divert socket with a given 'divert_port' number (as specified in 95 * the matching ipfw rule), and they are tagged with a 16 bit cookie 96 * (representing the rule number of the matching ipfw rule), which 97 * is passed to process reading from the socket. 98 * 99 * Packets written to the divert socket are again tagged with a cookie 100 * (usually the same as above) and a destination address. 101 * If the destination address is INADDR_ANY then the packet is 102 * treated as outgoing and sent to ip_output(), otherwise it is 103 * treated as incoming and sent to ip_input(). 104 * In both cases, the packet is tagged with the cookie. 105 * 106 * On reinjection, processing in ip_input() and ip_output() 107 * will be exactly the same as for the original packet, except that 108 * ipfw processing will start at the rule number after the one 109 * written in the cookie (so, tagging a packet with a cookie of 0 110 * will cause it to be effectively considered as a standard packet). 111 */ 112 113 /* Internal variables */ 114 static struct inpcbinfo divcbinfo; 115 static struct inpcbportinfo divcbportinfo; 116 117 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 118 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 119 120 static struct mbuf *ip_divert(struct mbuf *, int, int); 121 122 /* 123 * Initialize divert connection block queue. 124 */ 125 void 126 div_init(void) 127 { 128 in_pcbinfo_init(&divcbinfo, 0, FALSE); 129 in_pcbportinfo_init(&divcbportinfo, 1, 0); 130 /* 131 * XXX We don't use the hash list for divert IP, but it's easier 132 * to allocate a one entry hash list than it is to check all 133 * over the place for hashbase == NULL. 134 */ 135 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); 136 in_pcbportinfo_set(&divcbinfo, &divcbportinfo, 1); 137 divcbinfo.wildcardhashbase = hashinit(1, M_PCB, 138 &divcbinfo.wildcardhashmask); 139 divcbinfo.ipi_size = sizeof(struct inpcb); 140 ip_divert_p = ip_divert; 141 } 142 143 /* 144 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets 145 * with that protocol number to enter the system from the outside. 146 */ 147 int 148 div_input(struct mbuf **mp, int *offp, int proto) 149 { 150 struct mbuf *m = *mp; 151 152 ipstat.ips_noproto++; 153 m_freem(m); 154 return(IPPROTO_DONE); 155 } 156 157 /* 158 * Divert a packet by passing it up to the divert socket at port 'port'. 159 * 160 * Setup generic address and protocol structures for div_input routine, 161 * then pass them along with mbuf chain. 162 */ 163 static void 164 div_packet(struct mbuf *m, int incoming, int port) 165 { 166 struct sockaddr_in divsrc = { sizeof divsrc, AF_INET }; 167 struct inpcb *inp; 168 struct socket *sa; 169 struct m_tag *mtag; 170 struct divert_info *divinfo; 171 u_int16_t nport; 172 173 ASSERT_IN_NETISR(0); 174 175 /* Locate the divert info */ 176 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 177 divinfo = m_tag_data(mtag); 178 divsrc.sin_port = divinfo->skipto; 179 180 /* 181 * Record receive interface address, if any. 182 * But only for incoming packets. 183 */ 184 divsrc.sin_addr.s_addr = 0; 185 if (incoming) { 186 struct ifaddr_container *ifac; 187 188 /* Find IP address for receive interface */ 189 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 190 ifa_link) { 191 struct ifaddr *ifa = ifac->ifa; 192 193 if (ifa->ifa_addr == NULL) 194 continue; 195 if (ifa->ifa_addr->sa_family != AF_INET) 196 continue; 197 divsrc.sin_addr = 198 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 199 break; 200 } 201 } 202 /* 203 * Record the incoming interface name whenever we have one. 204 */ 205 if (m->m_pkthdr.rcvif) { 206 /* 207 * Hide the actual interface name in there in the 208 * sin_zero array. XXX This needs to be moved to a 209 * different sockaddr type for divert, e.g. 210 * sockaddr_div with multiple fields like 211 * sockaddr_dl. Presently we have only 7 bytes 212 * but that will do for now as most interfaces 213 * are 4 or less + 2 or less bytes for unit. 214 * There is probably a faster way of doing this, 215 * possibly taking it from the sockaddr_dl on the iface. 216 * This solves the problem of a P2P link and a LAN interface 217 * having the same address, which can result in the wrong 218 * interface being assigned to the packet when fed back 219 * into the divert socket. Theoretically if the daemon saves 220 * and re-uses the sockaddr_in as suggested in the man pages, 221 * this iface name will come along for the ride. 222 * (see div_output for the other half of this.) 223 */ 224 ksnprintf(divsrc.sin_zero, sizeof divsrc.sin_zero, "%s", 225 m->m_pkthdr.rcvif->if_xname); 226 } 227 228 /* Put packet on socket queue, if any */ 229 sa = NULL; 230 nport = htons((u_int16_t)port); 231 232 /* 233 * Following loop to locate the inpcb is MPSAFE since the inpcb 234 * insertion/removal happens on the same CPU (CPU0). 235 */ 236 LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) { 237 if (inp->inp_flags & INP_PLACEMARKER) 238 continue; 239 if (inp->inp_lport == nport) 240 sa = inp->inp_socket; 241 } 242 if (sa) { 243 lwkt_gettoken(&sa->so_rcv.ssb_token); 244 if (ssb_appendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, NULL) == 0) 245 m_freem(m); 246 else 247 sorwakeup(sa); 248 lwkt_reltoken(&sa->so_rcv.ssb_token); 249 } else { 250 m_freem(m); 251 ipstat.ips_noproto++; 252 ipstat.ips_delivered--; 253 } 254 } 255 256 static void 257 div_packet_handler(netmsg_t msg) 258 { 259 struct mbuf *m; 260 int port, incoming = 0; 261 262 m = msg->packet.nm_packet; 263 264 port = msg->lmsg.u.ms_result32 & 0xffff; 265 if (msg->lmsg.u.ms_result32 & DIV_INPUT) 266 incoming = 1; 267 div_packet(m, incoming, port); 268 /* no reply, msg embedded in mbuf */ 269 } 270 271 static void 272 divert_packet(struct mbuf *m, int incoming) 273 { 274 struct m_tag *mtag; 275 struct divert_info *divinfo; 276 int port; 277 278 M_ASSERTPKTHDR(m); 279 280 /* Assure header */ 281 if (m->m_len < sizeof(struct ip) && 282 (m = m_pullup(m, sizeof(struct ip))) == NULL) 283 return; 284 285 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 286 KASSERT(mtag != NULL, ("%s no divert tag!", __func__)); 287 divinfo = m_tag_data(mtag); 288 289 port = divinfo->port; 290 KASSERT(port != 0, ("%s: port=0", __func__)); 291 292 if (mycpuid != 0) { 293 struct netmsg_packet *nmp; 294 295 nmp = &m->m_hdr.mh_netmsg; 296 netmsg_init(&nmp->base, NULL, &netisr_apanic_rport, 297 0, div_packet_handler); 298 nmp->nm_packet = m; 299 300 nmp->base.lmsg.u.ms_result32 = port; /* port is 16bits */ 301 if (incoming) 302 nmp->base.lmsg.u.ms_result32 |= DIV_INPUT; 303 else 304 nmp->base.lmsg.u.ms_result32 |= DIV_OUTPUT; 305 306 lwkt_sendmsg(netisr_cpuport(0), &nmp->base.lmsg); 307 } else { 308 div_packet(m, incoming, port); 309 } 310 } 311 312 /* 313 * Deliver packet back into the IP processing machinery. 314 * 315 * If no address specified, or address is 0.0.0.0, send to ip_output(); 316 * otherwise, send to ip_input() and mark as having been received on 317 * the interface with that address. 318 */ 319 static int 320 div_output(struct socket *so, struct mbuf *m, 321 struct sockaddr_in *sin, struct mbuf *control) 322 { 323 int error = 0; 324 struct m_tag *mtag; 325 struct divert_info *divinfo; 326 327 ASSERT_IN_NETISR(0); 328 329 if (control) 330 m_freem(control); /* XXX */ 331 332 /* 333 * Prepare the tag for divert info. Note that a packet 334 * with a 0 tag in mh_data is effectively untagged, 335 * so we could optimize that case. 336 */ 337 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(*divinfo), M_NOWAIT); 338 if (mtag == NULL) { 339 error = ENOBUFS; 340 goto cantsend; 341 } 342 m_tag_prepend(m, mtag); 343 344 /* Loopback avoidance and state recovery */ 345 divinfo = m_tag_data(mtag); 346 if (sin) 347 divinfo->skipto = sin->sin_port; 348 else 349 divinfo->skipto = 0; 350 351 /* Reinject packet into the system as incoming or outgoing */ 352 if (DIV_IS_OUTPUT(sin)) { 353 struct ip *const ip = mtod(m, struct ip *); 354 355 /* Don't allow packet length sizes that will crash */ 356 if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) { 357 error = EINVAL; 358 goto cantsend; 359 } 360 361 /* Convert fields to host order for ip_output() */ 362 ip->ip_len = ntohs(ip->ip_len); 363 ip->ip_off = ntohs(ip->ip_off); 364 365 /* Send packet to output processing */ 366 ipstat.ips_rawout++; /* XXX */ 367 error = ip_output(m, NULL, NULL, 368 (so->so_options & SO_DONTROUTE) | 369 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 370 NULL, NULL); 371 } else { 372 ip_input(m); 373 } 374 return error; 375 376 cantsend: 377 m_freem(m); 378 return error; 379 } 380 381 static void 382 div_attach(netmsg_t msg) 383 { 384 struct socket *so = msg->attach.base.nm_so; 385 int proto = msg->attach.nm_proto; 386 struct pru_attach_info *ai = msg->attach.nm_ai; 387 struct inpcb *inp; 388 int error; 389 390 ASSERT_IN_NETISR(0); 391 392 inp = so->so_pcb; 393 if (inp) 394 panic("div_attach"); 395 error = priv_check_cred(ai->p_ucred, PRIV_ROOT, NULL_CRED_OKAY); 396 if (error) 397 goto out; 398 399 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit); 400 if (error) 401 goto out; 402 error = in_pcballoc(so, &divcbinfo); 403 if (error) 404 goto out; 405 inp = (struct inpcb *)so->so_pcb; 406 inp->inp_ip_p = proto; 407 inp->inp_flags |= INP_HDRINCL; 408 /* 409 * The socket is always "connected" because 410 * we always know "where" to send the packet. 411 */ 412 sosetstate(so, SS_ISCONNECTED); 413 error = 0; 414 out: 415 lwkt_replymsg(&msg->attach.base.lmsg, error); 416 } 417 418 static void 419 div_detach(netmsg_t msg) 420 { 421 struct socket *so = msg->detach.base.nm_so; 422 struct inpcb *inp; 423 424 ASSERT_IN_NETISR(0); 425 426 inp = so->so_pcb; 427 if (inp == NULL) 428 panic("div_detach"); 429 in_pcbdetach(inp); 430 lwkt_replymsg(&msg->detach.base.lmsg, 0); 431 } 432 433 static void 434 div_abort(netmsg_t msg) 435 { 436 /* 437 * Divert socket does not support listen(2), 438 * so this should never be called. 439 */ 440 panic("div_abort is called"); 441 } 442 443 static void 444 div_disconnect(netmsg_t msg) 445 { 446 struct socket *so = msg->disconnect.base.nm_so; 447 int error; 448 449 ASSERT_IN_NETISR(0); 450 451 if (so->so_state & SS_ISCONNECTED) { 452 soisdisconnected(so); 453 error = 0; 454 } else { 455 error = ENOTCONN; 456 } 457 lwkt_replymsg(&msg->disconnect.base.lmsg, error); 458 } 459 460 static void 461 div_bind(netmsg_t msg) 462 { 463 struct socket *so = msg->bind.base.nm_so; 464 struct sockaddr *nam = msg->bind.nm_nam; 465 int error; 466 467 ASSERT_IN_NETISR(0); 468 469 /* 470 * in_pcbbind assumes that nam is a sockaddr_in 471 * and in_pcbbind requires a valid address. Since divert 472 * sockets don't we need to make sure the address is 473 * filled in properly. 474 * XXX -- divert should not be abusing in_pcbind 475 * and should probably have its own family. 476 */ 477 if (nam->sa_family != AF_INET) { 478 error = EAFNOSUPPORT; 479 } else { 480 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 481 error = in_pcbbind(so->so_pcb, nam, msg->bind.nm_td); 482 } 483 lwkt_replymsg(&msg->bind.base.lmsg, error); 484 } 485 486 static void 487 div_shutdown(netmsg_t msg) 488 { 489 struct socket *so = msg->shutdown.base.nm_so; 490 491 ASSERT_IN_NETISR(0); 492 493 socantsendmore(so); 494 495 lwkt_replymsg(&msg->shutdown.base.lmsg, 0); 496 } 497 498 static void 499 div_send(netmsg_t msg) 500 { 501 struct socket *so = msg->send.base.nm_so; 502 struct mbuf *m = msg->send.nm_m; 503 struct sockaddr *nam = msg->send.nm_addr; 504 struct mbuf *control = msg->send.nm_control; 505 int error; 506 507 /* Length check already done in ip_hashfn() */ 508 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf")); 509 510 /* Send packet */ 511 error = div_output(so, m, (struct sockaddr_in *)nam, control); 512 lwkt_replymsg(&msg->send.base.lmsg, error); 513 } 514 515 SYSCTL_DECL(_net_inet_divert); 516 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 1, 517 in_pcblist_range, "S,xinpcb", "List of active divert sockets"); 518 519 struct pr_usrreqs div_usrreqs = { 520 .pru_abort = div_abort, 521 .pru_accept = pr_generic_notsupp, 522 .pru_attach = div_attach, 523 .pru_bind = div_bind, 524 .pru_connect = pr_generic_notsupp, 525 .pru_connect2 = pr_generic_notsupp, 526 .pru_control = in_control_dispatch, 527 .pru_detach = div_detach, 528 .pru_disconnect = div_disconnect, 529 .pru_listen = pr_generic_notsupp, 530 .pru_peeraddr = in_setpeeraddr_dispatch, 531 .pru_rcvd = pr_generic_notsupp, 532 .pru_rcvoob = pr_generic_notsupp, 533 .pru_send = div_send, 534 .pru_sense = pru_sense_null, 535 .pru_shutdown = div_shutdown, 536 .pru_sockaddr = in_setsockaddr_dispatch, 537 .pru_sosend = sosend, 538 .pru_soreceive = soreceive 539 }; 540 541 static struct mbuf * 542 ip_divert_out(struct mbuf *m, int tee) 543 { 544 struct mbuf *clone = NULL; 545 struct ip *ip = mtod(m, struct ip *); 546 547 /* Clone packet if we're doing a 'tee' */ 548 if (tee) 549 clone = m_dup(m, M_NOWAIT); 550 551 /* 552 * XXX 553 * delayed checksums are not currently compatible 554 * with divert sockets. 555 */ 556 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 557 in_delayed_cksum(m); 558 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 559 } 560 561 /* Restore packet header fields to original values */ 562 ip->ip_len = htons(ip->ip_len); 563 ip->ip_off = htons(ip->ip_off); 564 565 /* Deliver packet to divert input routine */ 566 divert_packet(m, 0); 567 568 /* If 'tee', continue with original packet */ 569 return clone; 570 } 571 572 static struct mbuf * 573 ip_divert_in(struct mbuf *m, int tee) 574 { 575 struct mbuf *clone = NULL; 576 struct ip *ip = mtod(m, struct ip *); 577 struct m_tag *mtag; 578 579 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 580 const struct divert_info *divinfo; 581 u_short frag_off; 582 int hlen; 583 584 /* 585 * Only trust divert info in the fragment 586 * at offset 0. 587 */ 588 frag_off = ip->ip_off << 3; 589 if (frag_off != 0) { 590 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 591 m_tag_delete(m, mtag); 592 } 593 594 /* 595 * Attempt reassembly; if it succeeds, proceed. 596 * ip_reass() will return a different mbuf. 597 */ 598 m = ip_reass(m); 599 if (m == NULL) 600 return NULL; 601 ip = mtod(m, struct ip *); 602 603 /* Caller need to redispatch the packet, if it is for us */ 604 m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH; 605 606 /* 607 * Get the header length of the reassembled 608 * packet 609 */ 610 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 611 612 /* 613 * Restore original checksum before diverting 614 * packet 615 */ 616 ip->ip_len += hlen; 617 ip->ip_len = htons(ip->ip_len); 618 ip->ip_off = htons(ip->ip_off); 619 ip->ip_sum = 0; 620 if (hlen == sizeof(struct ip)) 621 ip->ip_sum = in_cksum_hdr(ip); 622 else 623 ip->ip_sum = in_cksum(m, hlen); 624 ip->ip_off = ntohs(ip->ip_off); 625 ip->ip_len = ntohs(ip->ip_len); 626 627 /* 628 * Only use the saved divert info 629 */ 630 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 631 if (mtag == NULL) { 632 /* Wrongly configured ipfw */ 633 kprintf("ip_input no divert info\n"); 634 m_freem(m); 635 return NULL; 636 } 637 divinfo = m_tag_data(mtag); 638 tee = divinfo->tee; 639 } 640 641 /* 642 * Divert or tee packet to the divert protocol if 643 * required. 644 */ 645 646 /* Clone packet if we're doing a 'tee' */ 647 if (tee) 648 clone = m_dup(m, M_NOWAIT); 649 650 /* 651 * Restore packet header fields to original 652 * values 653 */ 654 ip->ip_len = htons(ip->ip_len); 655 ip->ip_off = htons(ip->ip_off); 656 657 /* Deliver packet to divert input routine */ 658 divert_packet(m, 1); 659 660 /* Catch invalid reference */ 661 m = NULL; 662 ip = NULL; 663 664 ipstat.ips_delivered++; 665 666 /* If 'tee', continue with original packet */ 667 if (clone != NULL) { 668 /* 669 * Complete processing of the packet. 670 * XXX Better safe than sorry, remove the DIVERT tag. 671 */ 672 mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL); 673 KKASSERT(mtag != NULL); 674 m_tag_delete(clone, mtag); 675 } 676 return clone; 677 } 678 679 static struct mbuf * 680 ip_divert(struct mbuf *m, int tee, int incoming) 681 { 682 struct mbuf *ret; 683 684 if (incoming) 685 ret = ip_divert_in(m, tee); 686 else 687 ret = ip_divert_out(m, tee); 688 return ret; 689 } 690