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; 115 116 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 117 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 118 119 static struct mbuf *ip_divert(struct mbuf *, int, int); 120 121 static struct lwkt_token div_token = LWKT_TOKEN_INITIALIZER(div_token); 122 123 /* 124 * Initialize divert connection block queue. 125 */ 126 void 127 div_init(void) 128 { 129 in_pcbinfo_init(&divcbinfo); 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 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask); 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 /* Locate the divert info */ 174 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 175 divinfo = m_tag_data(mtag); 176 divsrc.sin_port = divinfo->skipto; 177 178 /* 179 * Record receive interface address, if any. 180 * But only for incoming packets. 181 */ 182 divsrc.sin_addr.s_addr = 0; 183 if (incoming) { 184 struct ifaddr_container *ifac; 185 186 /* Find IP address for receive interface */ 187 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 188 ifa_link) { 189 struct ifaddr *ifa = ifac->ifa; 190 191 if (ifa->ifa_addr == NULL) 192 continue; 193 if (ifa->ifa_addr->sa_family != AF_INET) 194 continue; 195 divsrc.sin_addr = 196 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 197 break; 198 } 199 } 200 /* 201 * Record the incoming interface name whenever we have one. 202 */ 203 if (m->m_pkthdr.rcvif) { 204 /* 205 * Hide the actual interface name in there in the 206 * sin_zero array. XXX This needs to be moved to a 207 * different sockaddr type for divert, e.g. 208 * sockaddr_div with multiple fields like 209 * sockaddr_dl. Presently we have only 7 bytes 210 * but that will do for now as most interfaces 211 * are 4 or less + 2 or less bytes for unit. 212 * There is probably a faster way of doing this, 213 * possibly taking it from the sockaddr_dl on the iface. 214 * This solves the problem of a P2P link and a LAN interface 215 * having the same address, which can result in the wrong 216 * interface being assigned to the packet when fed back 217 * into the divert socket. Theoretically if the daemon saves 218 * and re-uses the sockaddr_in as suggested in the man pages, 219 * this iface name will come along for the ride. 220 * (see div_output for the other half of this.) 221 */ 222 ksnprintf(divsrc.sin_zero, sizeof divsrc.sin_zero, "%s", 223 m->m_pkthdr.rcvif->if_xname); 224 } 225 226 /* Put packet on socket queue, if any */ 227 sa = NULL; 228 nport = htons((u_int16_t)port); 229 230 /* 231 * XXX 232 * Following loop to locate the inpcb is MPSAFE since the inpcb 233 * insertion/removal happens on the same CPU (CPU0), however, 234 * saving/testing the socket pointer is not MPSAFE. So we still 235 * need to hold BGL here. 236 */ 237 lwkt_gettoken(&div_token); 238 LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) { 239 if (inp->inp_flags & INP_PLACEMARKER) 240 continue; 241 if (inp->inp_lport == nport) 242 sa = inp->inp_socket; 243 } 244 if (sa) { 245 lwkt_gettoken(&sa->so_rcv.ssb_token); 246 if (ssb_appendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, NULL) == 0) 247 m_freem(m); 248 else 249 sorwakeup(sa); 250 lwkt_reltoken(&sa->so_rcv.ssb_token); 251 } else { 252 m_freem(m); 253 ipstat.ips_noproto++; 254 ipstat.ips_delivered--; 255 } 256 lwkt_reltoken(&div_token); 257 } 258 259 static void 260 div_packet_handler(netmsg_t msg) 261 { 262 struct mbuf *m; 263 int port, incoming = 0; 264 265 m = msg->packet.nm_packet; 266 267 port = msg->lmsg.u.ms_result32 & 0xffff; 268 if (msg->lmsg.u.ms_result32 & DIV_INPUT) 269 incoming = 1; 270 div_packet(m, incoming, port); 271 /* no reply, msg embedded in mbuf */ 272 } 273 274 static void 275 divert_packet(struct mbuf *m, int incoming) 276 { 277 struct m_tag *mtag; 278 struct divert_info *divinfo; 279 int port; 280 281 M_ASSERTPKTHDR(m); 282 283 /* Assure header */ 284 if (m->m_len < sizeof(struct ip) && 285 (m = m_pullup(m, sizeof(struct ip))) == NULL) 286 return; 287 288 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 289 KASSERT(mtag != NULL, ("%s no divert tag!", __func__)); 290 divinfo = m_tag_data(mtag); 291 292 port = divinfo->port; 293 KASSERT(port != 0, ("%s: port=0", __func__)); 294 295 if (mycpuid != 0) { 296 struct netmsg_packet *nmp; 297 298 nmp = &m->m_hdr.mh_netmsg; 299 netmsg_init(&nmp->base, NULL, &netisr_apanic_rport, 300 0, div_packet_handler); 301 nmp->nm_packet = m; 302 303 nmp->base.lmsg.u.ms_result32 = port; /* port is 16bits */ 304 if (incoming) 305 nmp->base.lmsg.u.ms_result32 |= DIV_INPUT; 306 else 307 nmp->base.lmsg.u.ms_result32 |= DIV_OUTPUT; 308 309 lwkt_sendmsg(netisr_cpuport(0), &nmp->base.lmsg); 310 } else { 311 div_packet(m, incoming, port); 312 } 313 } 314 315 /* 316 * Deliver packet back into the IP processing machinery. 317 * 318 * If no address specified, or address is 0.0.0.0, send to ip_output(); 319 * otherwise, send to ip_input() and mark as having been received on 320 * the interface with that address. 321 */ 322 static int 323 div_output(struct socket *so, struct mbuf *m, 324 struct sockaddr_in *sin, struct mbuf *control) 325 { 326 int error = 0; 327 struct m_tag *mtag; 328 struct divert_info *divinfo; 329 330 if (control) 331 m_freem(control); /* XXX */ 332 333 /* 334 * Prepare the tag for divert info. Note that a packet 335 * with a 0 tag in mh_data is effectively untagged, 336 * so we could optimize that case. 337 */ 338 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(*divinfo), MB_DONTWAIT); 339 if (mtag == NULL) { 340 error = ENOBUFS; 341 goto cantsend; 342 } 343 m_tag_prepend(m, mtag); 344 345 /* Loopback avoidance and state recovery */ 346 divinfo = m_tag_data(mtag); 347 if (sin) 348 divinfo->skipto = sin->sin_port; 349 else 350 divinfo->skipto = 0; 351 352 /* Reinject packet into the system as incoming or outgoing */ 353 if (DIV_IS_OUTPUT(sin)) { 354 struct ip *const ip = mtod(m, struct ip *); 355 356 /* Don't allow packet length sizes that will crash */ 357 if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) { 358 error = EINVAL; 359 goto cantsend; 360 } 361 362 /* Convert fields to host order for ip_output() */ 363 ip->ip_len = ntohs(ip->ip_len); 364 ip->ip_off = ntohs(ip->ip_off); 365 366 /* Send packet to output processing */ 367 ipstat.ips_rawout++; /* XXX */ 368 error = ip_output(m, NULL, NULL, 369 (so->so_options & SO_DONTROUTE) | 370 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 371 NULL, NULL); 372 } else { 373 ip_input(m); 374 } 375 return error; 376 377 cantsend: 378 m_freem(m); 379 return error; 380 } 381 382 static void 383 div_attach(netmsg_t msg) 384 { 385 struct socket *so = msg->attach.base.nm_so; 386 int proto = msg->attach.nm_proto; 387 struct pru_attach_info *ai = msg->attach.nm_ai; 388 struct inpcb *inp; 389 int error; 390 391 inp = so->so_pcb; 392 if (inp) 393 panic("div_attach"); 394 error = priv_check_cred(ai->p_ucred, PRIV_ROOT, NULL_CRED_OKAY); 395 if (error) 396 goto out; 397 398 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit); 399 if (error) 400 goto out; 401 lwkt_gettoken(&div_token); 402 sosetport(so, netisr_cpuport(0)); 403 error = in_pcballoc(so, &divcbinfo); 404 if (error) { 405 lwkt_reltoken(&div_token); 406 goto out; 407 } 408 inp = (struct inpcb *)so->so_pcb; 409 inp->inp_ip_p = proto; 410 inp->inp_vflag |= INP_IPV4; 411 inp->inp_flags |= INP_HDRINCL; 412 /* 413 * The socket is always "connected" because 414 * we always know "where" to send the packet. 415 */ 416 sosetstate(so, SS_ISCONNECTED); 417 lwkt_reltoken(&div_token); 418 error = 0; 419 out: 420 lwkt_replymsg(&msg->attach.base.lmsg, error); 421 } 422 423 static void 424 div_detach(netmsg_t msg) 425 { 426 struct socket *so = msg->detach.base.nm_so; 427 struct inpcb *inp; 428 429 inp = so->so_pcb; 430 if (inp == NULL) 431 panic("div_detach"); 432 in_pcbdetach(inp); 433 lwkt_replymsg(&msg->detach.base.lmsg, 0); 434 } 435 436 /* 437 * NOTE: (so) is referenced from soabort*() and netmsg_pru_abort() 438 * will sofree() it when we return. 439 */ 440 static void 441 div_abort(netmsg_t msg) 442 { 443 struct socket *so = msg->abort.base.nm_so; 444 445 soisdisconnected(so); 446 div_detach(msg); 447 /* msg invalid now */ 448 } 449 450 static void 451 div_disconnect(netmsg_t msg) 452 { 453 struct socket *so = msg->disconnect.base.nm_so; 454 int error; 455 456 if (so->so_state & SS_ISCONNECTED) { 457 soreference(so); 458 div_abort(msg); 459 /* msg invalid now */ 460 sofree(so); 461 return; 462 } 463 error = ENOTCONN; 464 lwkt_replymsg(&msg->disconnect.base.lmsg, error); 465 } 466 467 static void 468 div_bind(netmsg_t msg) 469 { 470 struct socket *so = msg->bind.base.nm_so; 471 struct sockaddr *nam = msg->bind.nm_nam; 472 int error; 473 474 /* 475 * in_pcbbind assumes that nam is a sockaddr_in 476 * and in_pcbbind requires a valid address. Since divert 477 * sockets don't we need to make sure the address is 478 * filled in properly. 479 * XXX -- divert should not be abusing in_pcbind 480 * and should probably have its own family. 481 */ 482 if (nam->sa_family != AF_INET) { 483 error = EAFNOSUPPORT; 484 } else { 485 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 486 error = in_pcbbind(so->so_pcb, nam, msg->bind.nm_td); 487 } 488 lwkt_replymsg(&msg->bind.base.lmsg, error); 489 } 490 491 static void 492 div_shutdown(netmsg_t msg) 493 { 494 struct socket *so = msg->shutdown.base.nm_so; 495 496 socantsendmore(so); 497 498 lwkt_replymsg(&msg->shutdown.base.lmsg, 0); 499 } 500 501 static void 502 div_send(netmsg_t msg) 503 { 504 struct socket *so = msg->send.base.nm_so; 505 struct mbuf *m = msg->send.nm_m; 506 struct sockaddr *nam = msg->send.nm_addr; 507 struct mbuf *control = msg->send.nm_control; 508 int error; 509 510 /* Length check already done in ip_hashfn() */ 511 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf")); 512 513 /* Send packet */ 514 error = div_output(so, m, (struct sockaddr_in *)nam, control); 515 lwkt_replymsg(&msg->send.base.lmsg, error); 516 } 517 518 SYSCTL_DECL(_net_inet_divert); 519 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 0, 520 in_pcblist_global, "S,xinpcb", "List of active divert sockets"); 521 522 struct pr_usrreqs div_usrreqs = { 523 .pru_abort = div_abort, 524 .pru_accept = pr_generic_notsupp, 525 .pru_attach = div_attach, 526 .pru_bind = div_bind, 527 .pru_connect = pr_generic_notsupp, 528 .pru_connect2 = pr_generic_notsupp, 529 .pru_control = in_control_dispatch, 530 .pru_detach = div_detach, 531 .pru_disconnect = div_disconnect, 532 .pru_listen = pr_generic_notsupp, 533 .pru_peeraddr = in_setpeeraddr_dispatch, 534 .pru_rcvd = pr_generic_notsupp, 535 .pru_rcvoob = pr_generic_notsupp, 536 .pru_send = div_send, 537 .pru_sense = pru_sense_null, 538 .pru_shutdown = div_shutdown, 539 .pru_sockaddr = in_setsockaddr_dispatch, 540 .pru_sosend = sosend, 541 .pru_soreceive = soreceive 542 }; 543 544 static struct mbuf * 545 ip_divert_out(struct mbuf *m, int tee) 546 { 547 struct mbuf *clone = NULL; 548 struct ip *ip = mtod(m, struct ip *); 549 550 /* Clone packet if we're doing a 'tee' */ 551 if (tee) 552 clone = m_dup(m, MB_DONTWAIT); 553 554 /* 555 * XXX 556 * delayed checksums are not currently compatible 557 * with divert sockets. 558 */ 559 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 560 in_delayed_cksum(m); 561 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 562 } 563 564 /* Restore packet header fields to original values */ 565 ip->ip_len = htons(ip->ip_len); 566 ip->ip_off = htons(ip->ip_off); 567 568 /* Deliver packet to divert input routine */ 569 divert_packet(m, 0); 570 571 /* If 'tee', continue with original packet */ 572 return clone; 573 } 574 575 static struct mbuf * 576 ip_divert_in(struct mbuf *m, int tee) 577 { 578 struct mbuf *clone = NULL; 579 struct ip *ip = mtod(m, struct ip *); 580 struct m_tag *mtag; 581 582 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 583 const struct divert_info *divinfo; 584 u_short frag_off; 585 int hlen; 586 587 /* 588 * Only trust divert info in the fragment 589 * at offset 0. 590 */ 591 frag_off = ip->ip_off << 3; 592 if (frag_off != 0) { 593 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 594 m_tag_delete(m, mtag); 595 } 596 597 /* 598 * Attempt reassembly; if it succeeds, proceed. 599 * ip_reass() will return a different mbuf. 600 */ 601 m = ip_reass(m); 602 if (m == NULL) 603 return NULL; 604 ip = mtod(m, struct ip *); 605 606 /* Caller need to redispatch the packet, if it is for us */ 607 m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH; 608 609 /* 610 * Get the header length of the reassembled 611 * packet 612 */ 613 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 614 615 /* 616 * Restore original checksum before diverting 617 * packet 618 */ 619 ip->ip_len += hlen; 620 ip->ip_len = htons(ip->ip_len); 621 ip->ip_off = htons(ip->ip_off); 622 ip->ip_sum = 0; 623 if (hlen == sizeof(struct ip)) 624 ip->ip_sum = in_cksum_hdr(ip); 625 else 626 ip->ip_sum = in_cksum(m, hlen); 627 ip->ip_off = ntohs(ip->ip_off); 628 ip->ip_len = ntohs(ip->ip_len); 629 630 /* 631 * Only use the saved divert info 632 */ 633 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 634 if (mtag == NULL) { 635 /* Wrongly configured ipfw */ 636 kprintf("ip_input no divert info\n"); 637 m_freem(m); 638 return NULL; 639 } 640 divinfo = m_tag_data(mtag); 641 tee = divinfo->tee; 642 } 643 644 /* 645 * Divert or tee packet to the divert protocol if 646 * required. 647 */ 648 649 /* Clone packet if we're doing a 'tee' */ 650 if (tee) 651 clone = m_dup(m, MB_DONTWAIT); 652 653 /* 654 * Restore packet header fields to original 655 * values 656 */ 657 ip->ip_len = htons(ip->ip_len); 658 ip->ip_off = htons(ip->ip_off); 659 660 /* Deliver packet to divert input routine */ 661 divert_packet(m, 1); 662 663 /* Catch invalid reference */ 664 m = NULL; 665 ip = NULL; 666 667 ipstat.ips_delivered++; 668 669 /* If 'tee', continue with original packet */ 670 if (clone != NULL) { 671 /* 672 * Complete processing of the packet. 673 * XXX Better safe than sorry, remove the DIVERT tag. 674 */ 675 mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL); 676 KKASSERT(mtag != NULL); 677 m_tag_delete(clone, mtag); 678 } 679 return clone; 680 } 681 682 static struct mbuf * 683 ip_divert(struct mbuf *m, int tee, int incoming) 684 { 685 struct mbuf *ret; 686 687 if (incoming) 688 ret = ip_divert_in(m, tee); 689 else 690 ret = ip_divert_out(m, tee); 691 return ret; 692 } 693