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 /* Optimization: have this preinitialized */ 115 static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET }; 116 117 /* 118 * Initialize divert connection block queue. 119 */ 120 void 121 div_init(void) 122 { 123 INP_INFO_LOCK_INIT(&divcbinfo, "div"); 124 LIST_INIT(&divcb); 125 divcbinfo.listhead = &divcb; 126 /* 127 * XXX We don't use the hash list for divert IP, but it's easier 128 * to allocate a one entry hash list than it is to check all 129 * over the place for hashbase == NULL. 130 */ 131 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); 132 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask); 133 divcbinfo.ipi_zone = uma_zcreate("divcb", sizeof(struct inpcb), 134 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 135 uma_zone_set_max(divcbinfo.ipi_zone, maxsockets); 136 } 137 138 /* 139 * IPPROTO_DIVERT is not in the real IP protocol number space; this 140 * function should never be called. Just in case, drop any packets. 141 */ 142 void 143 div_input(struct mbuf *m, int off) 144 { 145 ipstat.ips_noproto++; 146 m_freem(m); 147 } 148 149 /* 150 * Divert a packet by passing it up to the divert socket at port 'port'. 151 * 152 * Setup generic address and protocol structures for div_input routine, 153 * then pass them along with mbuf chain. 154 */ 155 void 156 divert_packet(struct mbuf *m, int incoming, int port, int rule) 157 { 158 struct ip *ip; 159 struct inpcb *inp; 160 struct socket *sa; 161 u_int16_t nport; 162 163 /* Sanity check */ 164 KASSERT(port != 0, ("%s: port=0", __func__)); 165 166 divsrc.sin_port = rule; /* record matching rule */ 167 168 /* Assure header */ 169 if (m->m_len < sizeof(struct ip) && 170 (m = m_pullup(m, sizeof(struct ip))) == 0) 171 return; 172 ip = mtod(m, struct ip *); 173 174 /* 175 * Record receive interface address, if any. 176 * But only for incoming packets. 177 */ 178 divsrc.sin_addr.s_addr = 0; 179 if (incoming) { 180 struct ifaddr *ifa; 181 182 /* Sanity check */ 183 KASSERT((m->m_flags & M_PKTHDR), ("%s: !PKTHDR", __func__)); 184 185 /* Find IP address for receive interface */ 186 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 187 if (ifa->ifa_addr == NULL) 188 continue; 189 if (ifa->ifa_addr->sa_family != AF_INET) 190 continue; 191 divsrc.sin_addr = 192 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 193 break; 194 } 195 } 196 /* 197 * Record the incoming interface name whenever we have one. 198 */ 199 bzero(&divsrc.sin_zero, sizeof(divsrc.sin_zero)); 200 if (m->m_pkthdr.rcvif) { 201 /* 202 * Hide the actual interface name in there in the 203 * sin_zero array. XXX This needs to be moved to a 204 * different sockaddr type for divert, e.g. 205 * sockaddr_div with multiple fields like 206 * sockaddr_dl. Presently we have only 7 bytes 207 * but that will do for now as most interfaces 208 * are 4 or less + 2 or less bytes for unit. 209 * There is probably a faster way of doing this, 210 * possibly taking it from the sockaddr_dl on the iface. 211 * This solves the problem of a P2P link and a LAN interface 212 * having the same address, which can result in the wrong 213 * interface being assigned to the packet when fed back 214 * into the divert socket. Theoretically if the daemon saves 215 * and re-uses the sockaddr_in as suggested in the man pages, 216 * this iface name will come along for the ride. 217 * (see div_output for the other half of this.) 218 */ 219 snprintf(divsrc.sin_zero, sizeof(divsrc.sin_zero), 220 "%s%d", m->m_pkthdr.rcvif->if_name, 221 m->m_pkthdr.rcvif->if_unit); 222 } 223 224 /* Put packet on socket queue, if any */ 225 sa = NULL; 226 nport = htons((u_int16_t)port); 227 LIST_FOREACH(inp, &divcb, inp_list) { 228 if (inp->inp_lport == nport) 229 sa = inp->inp_socket; 230 } 231 if (sa) { 232 if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, 233 m, (struct mbuf *)0) == 0) 234 m_freem(m); 235 else 236 sorwakeup(sa); 237 } else { 238 m_freem(m); 239 ipstat.ips_noproto++; 240 ipstat.ips_delivered--; 241 } 242 } 243 244 /* 245 * Deliver packet back into the IP processing machinery. 246 * 247 * If no address specified, or address is 0.0.0.0, send to ip_output(); 248 * otherwise, send to ip_input() and mark as having been received on 249 * the interface with that address. 250 */ 251 static int 252 div_output(struct socket *so, struct mbuf *m, 253 struct sockaddr_in *sin, struct mbuf *control) 254 { 255 int error = 0; 256 struct m_hdr divert_tag; 257 258 /* 259 * Prepare the tag for divert info. Note that a packet 260 * with a 0 tag in mh_data is effectively untagged, 261 * so we could optimize that case. 262 */ 263 divert_tag.mh_type = MT_TAG; 264 divert_tag.mh_flags = PACKET_TAG_DIVERT; 265 divert_tag.mh_next = m; 266 divert_tag.mh_data = 0; /* the matching rule # */ 267 m->m_pkthdr.rcvif = NULL; /* XXX is it necessary ? */ 268 269 #ifdef MAC 270 mac_create_mbuf_from_socket(so, m); 271 #endif 272 273 if (control) 274 m_freem(control); /* XXX */ 275 276 /* Loopback avoidance and state recovery */ 277 if (sin) { 278 int i; 279 280 divert_tag.mh_data = (caddr_t)(uintptr_t)sin->sin_port; 281 /* 282 * Find receive interface with the given name, stuffed 283 * (if it exists) in the sin_zero[] field. 284 * The name is user supplied data so don't trust its size 285 * or that it is zero terminated. 286 */ 287 for (i = 0; i < sizeof(sin->sin_zero) && sin->sin_zero[i]; i++) 288 ; 289 if ( i > 0 && i < sizeof(sin->sin_zero)) 290 m->m_pkthdr.rcvif = ifunit(sin->sin_zero); 291 } 292 293 /* Reinject packet into the system as incoming or outgoing */ 294 if (!sin || sin->sin_addr.s_addr == 0) { 295 struct inpcb *const inp = sotoinpcb(so); 296 struct ip *const ip = mtod(m, struct ip *); 297 298 /* 299 * Don't allow both user specified and setsockopt options, 300 * and don't allow packet length sizes that will crash 301 */ 302 if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) || 303 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { 304 error = EINVAL; 305 goto cantsend; 306 } 307 308 /* Convert fields to host order for ip_output() */ 309 ip->ip_len = ntohs(ip->ip_len); 310 ip->ip_off = ntohs(ip->ip_off); 311 312 /* Send packet to output processing */ 313 ipstat.ips_rawout++; /* XXX */ 314 error = ip_output((struct mbuf *)&divert_tag, 315 inp->inp_options, &inp->inp_route, 316 (so->so_options & SO_DONTROUTE) | 317 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 318 inp->inp_moptions, NULL); 319 } else { 320 if (m->m_pkthdr.rcvif == NULL) { 321 /* 322 * No luck with the name, check by IP address. 323 * Clear the port and the ifname to make sure 324 * there are no distractions for ifa_ifwithaddr. 325 */ 326 struct ifaddr *ifa; 327 328 bzero(sin->sin_zero, sizeof(sin->sin_zero)); 329 sin->sin_port = 0; 330 ifa = ifa_ifwithaddr((struct sockaddr *) sin); 331 if (ifa == NULL) { 332 error = EADDRNOTAVAIL; 333 goto cantsend; 334 } 335 m->m_pkthdr.rcvif = ifa->ifa_ifp; 336 } 337 /* Send packet to input processing */ 338 ip_input((struct mbuf *)&divert_tag); 339 } 340 341 return error; 342 343 cantsend: 344 m_freem(m); 345 return error; 346 } 347 348 static int 349 div_attach(struct socket *so, int proto, struct thread *td) 350 { 351 struct inpcb *inp; 352 int error, s; 353 354 inp = sotoinpcb(so); 355 if (inp) 356 panic("div_attach"); 357 if (td && (error = suser(td)) != 0) 358 return error; 359 360 error = soreserve(so, div_sendspace, div_recvspace); 361 if (error) 362 return error; 363 s = splnet(); 364 error = in_pcballoc(so, &divcbinfo, td); 365 splx(s); 366 if (error) 367 return error; 368 inp = (struct inpcb *)so->so_pcb; 369 inp->inp_ip_p = proto; 370 inp->inp_vflag |= INP_IPV4; 371 inp->inp_flags |= INP_HDRINCL; 372 /* The socket is always "connected" because 373 we always know "where" to send the packet */ 374 so->so_state |= SS_ISCONNECTED; 375 return 0; 376 } 377 378 static int 379 div_detach(struct socket *so) 380 { 381 struct inpcb *inp; 382 383 inp = sotoinpcb(so); 384 if (inp == 0) 385 panic("div_detach"); 386 in_pcbdetach(inp); 387 return 0; 388 } 389 390 static int 391 div_abort(struct socket *so) 392 { 393 soisdisconnected(so); 394 return div_detach(so); 395 } 396 397 static int 398 div_disconnect(struct socket *so) 399 { 400 if ((so->so_state & SS_ISCONNECTED) == 0) 401 return ENOTCONN; 402 return div_abort(so); 403 } 404 405 static int 406 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 407 { 408 struct inpcb *inp; 409 int s; 410 int error; 411 412 s = splnet(); 413 inp = sotoinpcb(so); 414 /* in_pcbbind assumes that nam is a sockaddr_in 415 * and in_pcbbind requires a valid address. Since divert 416 * sockets don't we need to make sure the address is 417 * filled in properly. 418 * XXX -- divert should not be abusing in_pcbind 419 * and should probably have its own family. 420 */ 421 if (nam->sa_family != AF_INET) 422 error = EAFNOSUPPORT; 423 else { 424 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 425 error = in_pcbbind(inp, nam, td); 426 } 427 splx(s); 428 return error; 429 } 430 431 static int 432 div_shutdown(struct socket *so) 433 { 434 socantsendmore(so); 435 return 0; 436 } 437 438 static int 439 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 440 struct mbuf *control, struct thread *td) 441 { 442 /* Packet must have a header (but that's about it) */ 443 if (m->m_len < sizeof (struct ip) && 444 (m = m_pullup(m, sizeof (struct ip))) == 0) { 445 ipstat.ips_toosmall++; 446 m_freem(m); 447 return EINVAL; 448 } 449 450 /* Send packet */ 451 return div_output(so, m, (struct sockaddr_in *)nam, control); 452 } 453 454 static int 455 div_pcblist(SYSCTL_HANDLER_ARGS) 456 { 457 int error, i, n, s; 458 struct inpcb *inp, **inp_list; 459 inp_gen_t gencnt; 460 struct xinpgen xig; 461 462 /* 463 * The process of preparing the TCB list is too time-consuming and 464 * resource-intensive to repeat twice on every request. 465 */ 466 if (req->oldptr == 0) { 467 n = divcbinfo.ipi_count; 468 req->oldidx = 2 * (sizeof xig) 469 + (n + n/8) * sizeof(struct xinpcb); 470 return 0; 471 } 472 473 if (req->newptr != 0) 474 return EPERM; 475 476 /* 477 * OK, now we're committed to doing something. 478 */ 479 s = splnet(); 480 gencnt = divcbinfo.ipi_gencnt; 481 n = divcbinfo.ipi_count; 482 splx(s); 483 484 xig.xig_len = sizeof xig; 485 xig.xig_count = n; 486 xig.xig_gen = gencnt; 487 xig.xig_sogen = so_gencnt; 488 error = SYSCTL_OUT(req, &xig, sizeof xig); 489 if (error) 490 return error; 491 492 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 493 if (inp_list == 0) 494 return ENOMEM; 495 496 s = splnet(); 497 for (inp = LIST_FIRST(divcbinfo.listhead), i = 0; inp && i < n; 498 inp = LIST_NEXT(inp, inp_list)) { 499 if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->td, inp)) 500 inp_list[i++] = inp; 501 } 502 splx(s); 503 n = i; 504 505 error = 0; 506 for (i = 0; i < n; i++) { 507 inp = inp_list[i]; 508 if (inp->inp_gencnt <= gencnt) { 509 struct xinpcb xi; 510 xi.xi_len = sizeof xi; 511 /* XXX should avoid extra copy */ 512 bcopy(inp, &xi.xi_inp, sizeof *inp); 513 if (inp->inp_socket) 514 sotoxsocket(inp->inp_socket, &xi.xi_socket); 515 error = SYSCTL_OUT(req, &xi, sizeof xi); 516 } 517 } 518 if (!error) { 519 /* 520 * Give the user an updated idea of our state. 521 * If the generation differs from what we told 522 * her before, she knows that something happened 523 * while we were processing this request, and it 524 * might be necessary to retry. 525 */ 526 s = splnet(); 527 xig.xig_gen = divcbinfo.ipi_gencnt; 528 xig.xig_sogen = so_gencnt; 529 xig.xig_count = divcbinfo.ipi_count; 530 splx(s); 531 error = SYSCTL_OUT(req, &xig, sizeof xig); 532 } 533 free(inp_list, M_TEMP); 534 return error; 535 } 536 537 /* 538 * This is the wrapper function for in_setsockaddr. We just pass down 539 * the pcbinfo for in_setpeeraddr to lock. 540 */ 541 static int 542 div_sockaddr(struct socket *so, struct sockaddr **nam) 543 { 544 return (in_setsockaddr(so, nam, &divcbinfo)); 545 } 546 547 /* 548 * This is the wrapper function for in_setpeeraddr. We just pass down 549 * the pcbinfo for in_setpeeraddr to lock. 550 */ 551 static int 552 div_peeraddr(struct socket *so, struct sockaddr **nam) 553 { 554 return (in_setpeeraddr(so, nam, &divcbinfo)); 555 } 556 557 558 SYSCTL_DECL(_net_inet_divert); 559 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0, 560 div_pcblist, "S,xinpcb", "List of active divert sockets"); 561 562 struct pr_usrreqs div_usrreqs = { 563 div_abort, pru_accept_notsupp, div_attach, div_bind, 564 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, 565 div_disconnect, pru_listen_notsupp, div_peeraddr, pru_rcvd_notsupp, 566 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, 567 div_sockaddr, sosend, soreceive, sopoll 568 }; 569