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. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * $FreeBSD$ 34 */ 35 36 #include "opt_inet.h" 37 #include "opt_ipfw.h" 38 #include "opt_ipdivert.h" 39 #include "opt_ipsec.h" 40 #include "opt_mac.h" 41 42 #ifndef INET 43 #error "IPDIVERT requires INET." 44 #endif 45 46 #include <sys/param.h> 47 #include <sys/kernel.h> 48 #include <sys/lock.h> 49 #include <sys/malloc.h> 50 #include <sys/mac.h> 51 #include <sys/mbuf.h> 52 #include <sys/proc.h> 53 #include <sys/protosw.h> 54 #include <sys/signalvar.h> 55 #include <sys/socket.h> 56 #include <sys/socketvar.h> 57 #include <sys/sx.h> 58 #include <sys/sysctl.h> 59 #include <sys/systm.h> 60 61 #include <vm/uma.h> 62 63 #include <net/if.h> 64 #include <net/route.h> 65 66 #include <netinet/in.h> 67 #include <netinet/in_pcb.h> 68 #include <netinet/in_systm.h> 69 #include <netinet/in_var.h> 70 #include <netinet/ip.h> 71 #include <netinet/ip_var.h> 72 73 /* 74 * Divert sockets 75 */ 76 77 /* 78 * Allocate enough space to hold a full IP packet 79 */ 80 #define DIVSNDQ (65536 + 100) 81 #define DIVRCVQ (65536 + 100) 82 83 /* 84 * Divert sockets work in conjunction with ipfw, see the divert(4) 85 * manpage for features. 86 * Internally, packets selected by ipfw in ip_input() or ip_output(), 87 * and never diverted before, are passed to the input queue of the 88 * divert socket with a given 'divert_port' number (as specified in 89 * the matching ipfw rule), and they are tagged with a 16 bit cookie 90 * (representing the rule number of the matching ipfw rule), which 91 * is passed to process reading from the socket. 92 * 93 * Packets written to the divert socket are again tagged with a cookie 94 * (usually the same as above) and a destination address. 95 * If the destination address is INADDR_ANY then the packet is 96 * treated as outgoing and sent to ip_output(), otherwise it is 97 * treated as incoming and sent to ip_input(). 98 * In both cases, the packet is tagged with the cookie. 99 * 100 * On reinjection, processing in ip_input() and ip_output() 101 * will be exactly the same as for the original packet, except that 102 * ipfw processing will start at the rule number after the one 103 * written in the cookie (so, tagging a packet with a cookie of 0 104 * will cause it to be effectively considered as a standard packet). 105 */ 106 107 /* Internal variables */ 108 static struct inpcbhead divcb; 109 static struct inpcbinfo divcbinfo; 110 111 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 112 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 113 114 /* 115 * Initialize divert connection block queue. 116 */ 117 void 118 div_init(void) 119 { 120 INP_INFO_LOCK_INIT(&divcbinfo, "div"); 121 LIST_INIT(&divcb); 122 divcbinfo.listhead = &divcb; 123 /* 124 * XXX We don't use the hash list for divert IP, but it's easier 125 * to allocate a one entry hash list than it is to check all 126 * over the place for hashbase == NULL. 127 */ 128 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); 129 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask); 130 divcbinfo.ipi_zone = uma_zcreate("divcb", sizeof(struct inpcb), 131 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 132 uma_zone_set_max(divcbinfo.ipi_zone, maxsockets); 133 } 134 135 /* 136 * IPPROTO_DIVERT is not in the real IP protocol number space; this 137 * function should never be called. Just in case, drop any packets. 138 */ 139 void 140 div_input(struct mbuf *m, int off) 141 { 142 ipstat.ips_noproto++; 143 m_freem(m); 144 } 145 146 /* 147 * Divert a packet by passing it up to the divert socket at port 'port'. 148 * 149 * Setup generic address and protocol structures for div_input routine, 150 * then pass them along with mbuf chain. 151 */ 152 void 153 divert_packet(struct mbuf *m, int incoming, int port, int rule) 154 { 155 struct ip *ip; 156 struct inpcb *inp; 157 struct socket *sa; 158 u_int16_t nport; 159 struct sockaddr_in divsrc; 160 161 /* Sanity check */ 162 KASSERT(port != 0, ("%s: port=0", __func__)); 163 164 /* Assure header */ 165 if (m->m_len < sizeof(struct ip) && 166 (m = m_pullup(m, sizeof(struct ip))) == 0) 167 return; 168 ip = mtod(m, struct ip *); 169 170 /* 171 * Record receive interface address, if any. 172 * But only for incoming packets. 173 */ 174 bzero(&divsrc, sizeof(divsrc)); 175 divsrc.sin_len = sizeof(divsrc); 176 divsrc.sin_family = AF_INET; 177 divsrc.sin_port = rule; /* record matching rule */ 178 if (incoming) { 179 struct ifaddr *ifa; 180 181 /* Sanity check */ 182 M_ASSERTPKTHDR(m); 183 184 /* Find IP address for receive interface */ 185 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 186 if (ifa->ifa_addr == NULL) 187 continue; 188 if (ifa->ifa_addr->sa_family != AF_INET) 189 continue; 190 divsrc.sin_addr = 191 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 192 break; 193 } 194 } 195 /* 196 * Record the incoming interface name whenever we have one. 197 */ 198 if (m->m_pkthdr.rcvif) { 199 /* 200 * Hide the actual interface name in there in the 201 * sin_zero array. XXX This needs to be moved to a 202 * different sockaddr type for divert, e.g. 203 * sockaddr_div with multiple fields like 204 * sockaddr_dl. Presently we have only 7 bytes 205 * but that will do for now as most interfaces 206 * are 4 or less + 2 or less bytes for unit. 207 * There is probably a faster way of doing this, 208 * possibly taking it from the sockaddr_dl on the iface. 209 * This solves the problem of a P2P link and a LAN interface 210 * having the same address, which can result in the wrong 211 * interface being assigned to the packet when fed back 212 * into the divert socket. Theoretically if the daemon saves 213 * and re-uses the sockaddr_in as suggested in the man pages, 214 * this iface name will come along for the ride. 215 * (see div_output for the other half of this.) 216 */ 217 snprintf(divsrc.sin_zero, sizeof(divsrc.sin_zero), 218 "%s%d", m->m_pkthdr.rcvif->if_name, 219 m->m_pkthdr.rcvif->if_unit); 220 } 221 222 /* Put packet on socket queue, if any */ 223 sa = NULL; 224 nport = htons((u_int16_t)port); 225 INP_INFO_RLOCK(&divcbinfo); 226 LIST_FOREACH(inp, &divcb, inp_list) { 227 INP_LOCK(inp); 228 /* XXX why does only one socket match? */ 229 if (inp->inp_lport == nport) { 230 sa = inp->inp_socket; 231 if (sbappendaddr(&sa->so_rcv, 232 (struct sockaddr *)&divsrc, m, 233 (struct mbuf *)0) == 0) 234 sa = NULL; /* force mbuf reclaim below */ 235 else 236 sorwakeup(sa); 237 INP_UNLOCK(inp); 238 break; 239 } 240 INP_UNLOCK(inp); 241 } 242 INP_INFO_RUNLOCK(&divcbinfo); 243 if (sa == NULL) { 244 m_freem(m); 245 ipstat.ips_noproto++; 246 ipstat.ips_delivered--; 247 } 248 } 249 250 /* 251 * Deliver packet back into the IP processing machinery. 252 * 253 * If no address specified, or address is 0.0.0.0, send to ip_output(); 254 * otherwise, send to ip_input() and mark as having been received on 255 * the interface with that address. 256 */ 257 static int 258 div_output(struct socket *so, struct mbuf *m, 259 struct sockaddr_in *sin, struct mbuf *control) 260 { 261 int error = 0; 262 struct m_hdr divert_tag; 263 264 /* 265 * Prepare the tag for divert info. Note that a packet 266 * with a 0 tag in mh_data is effectively untagged, 267 * so we could optimize that case. 268 */ 269 divert_tag.mh_type = MT_TAG; 270 divert_tag.mh_flags = PACKET_TAG_DIVERT; 271 divert_tag.mh_next = m; 272 divert_tag.mh_data = 0; /* the matching rule # */ 273 m->m_pkthdr.rcvif = NULL; /* XXX is it necessary ? */ 274 275 #ifdef MAC 276 mac_create_mbuf_from_socket(so, m); 277 #endif 278 279 if (control) 280 m_freem(control); /* XXX */ 281 282 /* Loopback avoidance and state recovery */ 283 if (sin) { 284 int i; 285 286 divert_tag.mh_data = (caddr_t)(uintptr_t)sin->sin_port; 287 /* 288 * Find receive interface with the given name, stuffed 289 * (if it exists) in the sin_zero[] field. 290 * The name is user supplied data so don't trust its size 291 * or that it is zero terminated. 292 */ 293 for (i = 0; i < sizeof(sin->sin_zero) && sin->sin_zero[i]; i++) 294 ; 295 if ( i > 0 && i < sizeof(sin->sin_zero)) 296 m->m_pkthdr.rcvif = ifunit(sin->sin_zero); 297 } 298 299 /* Reinject packet into the system as incoming or outgoing */ 300 if (!sin || sin->sin_addr.s_addr == 0) { 301 struct inpcb *const inp = sotoinpcb(so); 302 struct ip *const ip = mtod(m, struct ip *); 303 304 /* 305 * Don't allow both user specified and setsockopt options, 306 * and don't allow packet length sizes that will crash 307 */ 308 if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) || 309 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { 310 error = EINVAL; 311 goto cantsend; 312 } 313 314 /* Convert fields to host order for ip_output() */ 315 ip->ip_len = ntohs(ip->ip_len); 316 ip->ip_off = ntohs(ip->ip_off); 317 318 /* Send packet to output processing */ 319 ipstat.ips_rawout++; /* XXX */ 320 error = ip_output((struct mbuf *)&divert_tag, 321 inp->inp_options, &inp->inp_route, 322 (so->so_options & SO_DONTROUTE) | 323 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 324 inp->inp_moptions, NULL); 325 } else { 326 if (m->m_pkthdr.rcvif == NULL) { 327 /* 328 * No luck with the name, check by IP address. 329 * Clear the port and the ifname to make sure 330 * there are no distractions for ifa_ifwithaddr. 331 */ 332 struct ifaddr *ifa; 333 334 bzero(sin->sin_zero, sizeof(sin->sin_zero)); 335 sin->sin_port = 0; 336 ifa = ifa_ifwithaddr((struct sockaddr *) sin); 337 if (ifa == NULL) { 338 error = EADDRNOTAVAIL; 339 goto cantsend; 340 } 341 m->m_pkthdr.rcvif = ifa->ifa_ifp; 342 } 343 /* Send packet to input processing */ 344 ip_input((struct mbuf *)&divert_tag); 345 } 346 347 return error; 348 349 cantsend: 350 m_freem(m); 351 return error; 352 } 353 354 static int 355 div_attach(struct socket *so, int proto, struct thread *td) 356 { 357 struct inpcb *inp; 358 int error; 359 360 INP_INFO_WLOCK(&divcbinfo); 361 inp = sotoinpcb(so); 362 if (inp != 0) { 363 INP_INFO_WUNLOCK(&divcbinfo); 364 return EINVAL; 365 } 366 if (td && (error = suser(td)) != 0) { 367 INP_INFO_WUNLOCK(&divcbinfo); 368 return error; 369 } 370 error = soreserve(so, div_sendspace, div_recvspace); 371 if (error) { 372 INP_INFO_WUNLOCK(&divcbinfo); 373 return error; 374 } 375 error = in_pcballoc(so, &divcbinfo, td); 376 if (error) { 377 INP_INFO_WUNLOCK(&divcbinfo); 378 return error; 379 } 380 inp = (struct inpcb *)so->so_pcb; 381 INP_LOCK(inp); 382 INP_INFO_WUNLOCK(&divcbinfo); 383 inp->inp_ip_p = proto; 384 inp->inp_vflag |= INP_IPV4; 385 inp->inp_flags |= INP_HDRINCL; 386 /* The socket is always "connected" because 387 we always know "where" to send the packet */ 388 INP_UNLOCK(inp); 389 so->so_state |= SS_ISCONNECTED; 390 return 0; 391 } 392 393 static int 394 div_detach(struct socket *so) 395 { 396 struct inpcb *inp; 397 398 INP_INFO_WLOCK(&divcbinfo); 399 inp = sotoinpcb(so); 400 if (inp == 0) { 401 INP_INFO_WUNLOCK(&divcbinfo); 402 return EINVAL; 403 } 404 INP_LOCK(inp); 405 in_pcbdetach(inp); 406 INP_INFO_WUNLOCK(&divcbinfo); 407 return 0; 408 } 409 410 static int 411 div_abort(struct socket *so) 412 { 413 soisdisconnected(so); 414 return div_detach(so); 415 } 416 417 static int 418 div_disconnect(struct socket *so) 419 { 420 if ((so->so_state & SS_ISCONNECTED) == 0) 421 return ENOTCONN; 422 return div_abort(so); 423 } 424 425 static int 426 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 427 { 428 struct inpcb *inp; 429 int error; 430 431 INP_INFO_WLOCK(&divcbinfo); 432 inp = sotoinpcb(so); 433 if (inp == 0) { 434 INP_INFO_WUNLOCK(&divcbinfo); 435 return EINVAL; 436 } 437 /* in_pcbbind assumes that nam is a sockaddr_in 438 * and in_pcbbind requires a valid address. Since divert 439 * sockets don't we need to make sure the address is 440 * filled in properly. 441 * XXX -- divert should not be abusing in_pcbind 442 * and should probably have its own family. 443 */ 444 if (nam->sa_family != AF_INET) 445 error = EAFNOSUPPORT; 446 else { 447 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 448 INP_LOCK(inp); 449 error = in_pcbbind(inp, nam, td); 450 INP_UNLOCK(inp); 451 } 452 INP_INFO_WUNLOCK(&divcbinfo); 453 return error; 454 } 455 456 static int 457 div_shutdown(struct socket *so) 458 { 459 socantsendmore(so); 460 return 0; 461 } 462 463 static int 464 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 465 struct mbuf *control, struct thread *td) 466 { 467 /* Packet must have a header (but that's about it) */ 468 if (m->m_len < sizeof (struct ip) && 469 (m = m_pullup(m, sizeof (struct ip))) == 0) { 470 ipstat.ips_toosmall++; 471 m_freem(m); 472 return EINVAL; 473 } 474 475 /* Send packet */ 476 return div_output(so, m, (struct sockaddr_in *)nam, control); 477 } 478 479 static int 480 div_pcblist(SYSCTL_HANDLER_ARGS) 481 { 482 int error, i, n; 483 struct inpcb *inp, **inp_list; 484 inp_gen_t gencnt; 485 struct xinpgen xig; 486 487 /* 488 * The process of preparing the TCB list is too time-consuming and 489 * resource-intensive to repeat twice on every request. 490 */ 491 if (req->oldptr == 0) { 492 n = divcbinfo.ipi_count; 493 req->oldidx = 2 * (sizeof xig) 494 + (n + n/8) * sizeof(struct xinpcb); 495 return 0; 496 } 497 498 if (req->newptr != 0) 499 return EPERM; 500 501 /* 502 * OK, now we're committed to doing something. 503 */ 504 INP_INFO_RLOCK(&divcbinfo); 505 gencnt = divcbinfo.ipi_gencnt; 506 n = divcbinfo.ipi_count; 507 INP_INFO_RUNLOCK(&divcbinfo); 508 509 sysctl_wire_old_buffer(req, 2 * sizeof(xig) + n*sizeof(struct xinpcb)); 510 511 xig.xig_len = sizeof xig; 512 xig.xig_count = n; 513 xig.xig_gen = gencnt; 514 xig.xig_sogen = so_gencnt; 515 error = SYSCTL_OUT(req, &xig, sizeof xig); 516 if (error) 517 return error; 518 519 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 520 if (inp_list == 0) 521 return ENOMEM; 522 523 INP_INFO_RLOCK(&divcbinfo); 524 for (inp = LIST_FIRST(divcbinfo.listhead), i = 0; inp && i < n; 525 inp = LIST_NEXT(inp, inp_list)) { 526 INP_LOCK(inp); 527 if (inp->inp_gencnt <= gencnt && 528 cr_canseesocket(req->td->td_ucred, inp->inp_socket) == 0) 529 inp_list[i++] = inp; 530 INP_UNLOCK(inp); 531 } 532 INP_INFO_RUNLOCK(&divcbinfo); 533 n = i; 534 535 error = 0; 536 for (i = 0; i < n; i++) { 537 inp = inp_list[i]; 538 if (inp->inp_gencnt <= gencnt) { 539 struct xinpcb xi; 540 xi.xi_len = sizeof xi; 541 /* XXX should avoid extra copy */ 542 bcopy(inp, &xi.xi_inp, sizeof *inp); 543 if (inp->inp_socket) 544 sotoxsocket(inp->inp_socket, &xi.xi_socket); 545 error = SYSCTL_OUT(req, &xi, sizeof xi); 546 } 547 } 548 if (!error) { 549 /* 550 * Give the user an updated idea of our state. 551 * If the generation differs from what we told 552 * her before, she knows that something happened 553 * while we were processing this request, and it 554 * might be necessary to retry. 555 */ 556 INP_INFO_RLOCK(&divcbinfo); 557 xig.xig_gen = divcbinfo.ipi_gencnt; 558 xig.xig_sogen = so_gencnt; 559 xig.xig_count = divcbinfo.ipi_count; 560 INP_INFO_RUNLOCK(&divcbinfo); 561 error = SYSCTL_OUT(req, &xig, sizeof xig); 562 } 563 free(inp_list, M_TEMP); 564 return error; 565 } 566 567 /* 568 * This is the wrapper function for in_setsockaddr. We just pass down 569 * the pcbinfo for in_setpeeraddr to lock. 570 */ 571 static int 572 div_sockaddr(struct socket *so, struct sockaddr **nam) 573 { 574 return (in_setsockaddr(so, nam, &divcbinfo)); 575 } 576 577 /* 578 * This is the wrapper function for in_setpeeraddr. We just pass down 579 * the pcbinfo for in_setpeeraddr to lock. 580 */ 581 static int 582 div_peeraddr(struct socket *so, struct sockaddr **nam) 583 { 584 return (in_setpeeraddr(so, nam, &divcbinfo)); 585 } 586 587 588 SYSCTL_DECL(_net_inet_divert); 589 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0, 590 div_pcblist, "S,xinpcb", "List of active divert sockets"); 591 592 struct pr_usrreqs div_usrreqs = { 593 div_abort, pru_accept_notsupp, div_attach, div_bind, 594 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, 595 div_disconnect, pru_listen_notsupp, div_peeraddr, pru_rcvd_notsupp, 596 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, 597 div_sockaddr, sosend, soreceive, sopoll 598 }; 599