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 41 #ifndef INET 42 #error "IPDIVERT requires INET." 43 #endif 44 45 #include <sys/param.h> 46 #include <sys/kernel.h> 47 #include <sys/lock.h> 48 #include <sys/malloc.h> 49 #include <sys/mbuf.h> 50 #include <sys/proc.h> 51 #include <sys/protosw.h> 52 #include <sys/signalvar.h> 53 #include <sys/socket.h> 54 #include <sys/socketvar.h> 55 #include <sys/sx.h> 56 #include <sys/sysctl.h> 57 #include <sys/systm.h> 58 59 #include <vm/uma.h> 60 61 #include <net/if.h> 62 #include <net/route.h> 63 64 #include <netinet/in.h> 65 #include <netinet/in_pcb.h> 66 #include <netinet/in_systm.h> 67 #include <netinet/in_var.h> 68 #include <netinet/ip.h> 69 #include <netinet/ip_var.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 /* 82 * A 16 bit cookie is passed to and from the user process. 83 * The user process can send it back to help the caller know 84 * something about where the packet originally came from. 85 * 86 * In the case of ipfw, then the cookie is the rule that sent 87 * us here. On reinjection is is the rule after which processing 88 * should continue. Leaving it the same will make processing start 89 * at the rule number after that which sent it here. Setting it to 90 * 0 will restart processing at the beginning. 91 * 92 * For divert_packet(), ip_divert_cookie is an input value only. 93 * For div_output(), ip_divert_cookie is an output value only. 94 */ 95 u_int16_t ip_divert_cookie; 96 97 /* Internal variables */ 98 static struct inpcbhead divcb; 99 static struct inpcbinfo divcbinfo; 100 101 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 102 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 103 104 /* Optimization: have this preinitialized */ 105 static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET }; 106 107 /* Internal functions */ 108 static int div_output(struct socket *so, 109 struct mbuf *m, struct sockaddr *addr, struct mbuf *control); 110 111 /* 112 * Initialize divert connection block queue. 113 */ 114 void 115 div_init(void) 116 { 117 INP_INFO_LOCK_INIT(&divcbinfo, "div"); 118 LIST_INIT(&divcb); 119 divcbinfo.listhead = &divcb; 120 /* 121 * XXX We don't use the hash list for divert IP, but it's easier 122 * to allocate a one entry hash list than it is to check all 123 * over the place for hashbase == NULL. 124 */ 125 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); 126 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask); 127 divcbinfo.ipi_zone = uma_zcreate("divcb", sizeof(struct inpcb), 128 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 129 uma_zone_set_max(divcbinfo.ipi_zone, maxsockets); 130 } 131 132 /* 133 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets 134 * with that protocol number to enter the system from the outside. 135 */ 136 void 137 div_input(struct mbuf *m, int off) 138 { 139 ipstat.ips_noproto++; 140 m_freem(m); 141 } 142 143 /* 144 * Divert a packet by passing it up to the divert socket at port 'port'. 145 * 146 * Setup generic address and protocol structures for div_input routine, 147 * then pass them along with mbuf chain. 148 */ 149 void 150 divert_packet(struct mbuf *m, int incoming, int port) 151 { 152 struct ip *ip; 153 struct inpcb *inp; 154 struct socket *sa; 155 u_int16_t nport; 156 157 /* Sanity check */ 158 KASSERT(port != 0, ("%s: port=0", __func__)); 159 160 /* Record and reset divert cookie */ 161 divsrc.sin_port = ip_divert_cookie; 162 ip_divert_cookie = 0; 163 164 /* Assure header */ 165 if (m->m_len < sizeof(struct ip) && 166 (m = m_pullup(m, sizeof(struct ip))) == 0) { 167 return; 168 } 169 ip = mtod(m, struct ip *); 170 171 /* 172 * Record receive interface address, if any. 173 * But only for incoming packets. 174 */ 175 divsrc.sin_addr.s_addr = 0; 176 if (incoming) { 177 struct ifaddr *ifa; 178 179 /* Sanity check */ 180 KASSERT((m->m_flags & M_PKTHDR), ("%s: !PKTHDR", __func__)); 181 182 /* Find IP address for receive interface */ 183 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 184 if (ifa->ifa_addr == NULL) 185 continue; 186 if (ifa->ifa_addr->sa_family != AF_INET) 187 continue; 188 divsrc.sin_addr = 189 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 190 break; 191 } 192 } 193 /* 194 * Record the incoming interface name whenever we have one. 195 */ 196 bzero(&divsrc.sin_zero, sizeof(divsrc.sin_zero)); 197 if (m->m_pkthdr.rcvif) { 198 /* 199 * Hide the actual interface name in there in the 200 * sin_zero array. XXX This needs to be moved to a 201 * different sockaddr type for divert, e.g. 202 * sockaddr_div with multiple fields like 203 * sockaddr_dl. Presently we have only 7 bytes 204 * but that will do for now as most interfaces 205 * are 4 or less + 2 or less bytes for unit. 206 * There is probably a faster way of doing this, 207 * possibly taking it from the sockaddr_dl on the iface. 208 * This solves the problem of a P2P link and a LAN interface 209 * having the same address, which can result in the wrong 210 * interface being assigned to the packet when fed back 211 * into the divert socket. Theoretically if the daemon saves 212 * and re-uses the sockaddr_in as suggested in the man pages, 213 * this iface name will come along for the ride. 214 * (see div_output for the other half of this.) 215 */ 216 snprintf(divsrc.sin_zero, sizeof(divsrc.sin_zero), 217 "%s%d", m->m_pkthdr.rcvif->if_name, 218 m->m_pkthdr.rcvif->if_unit); 219 } 220 221 /* Put packet on socket queue, if any */ 222 sa = NULL; 223 nport = htons((u_int16_t)port); 224 LIST_FOREACH(inp, &divcb, inp_list) { 225 if (inp->inp_lport == nport) 226 sa = inp->inp_socket; 227 } 228 if (sa) { 229 if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, 230 m, (struct mbuf *)0) == 0) 231 m_freem(m); 232 else 233 sorwakeup(sa); 234 } else { 235 m_freem(m); 236 ipstat.ips_noproto++; 237 ipstat.ips_delivered--; 238 } 239 } 240 241 /* 242 * Deliver packet back into the IP processing machinery. 243 * 244 * If no address specified, or address is 0.0.0.0, send to ip_output(); 245 * otherwise, send to ip_input() and mark as having been received on 246 * the interface with that address. 247 */ 248 static int 249 div_output(so, m, addr, control) 250 struct socket *so; 251 register struct mbuf *m; 252 struct sockaddr *addr; 253 struct mbuf *control; 254 { 255 register struct inpcb *const inp = sotoinpcb(so); 256 register struct ip *const ip = mtod(m, struct ip *); 257 struct sockaddr_in *sin = (struct sockaddr_in *)addr; 258 int error = 0; 259 260 if (control) 261 m_freem(control); /* XXX */ 262 263 /* Loopback avoidance and state recovery */ 264 if (sin) { 265 int len = 0; 266 char *c = sin->sin_zero; 267 268 ip_divert_cookie = sin->sin_port; 269 270 /* 271 * Find receive interface with the given name or IP address. 272 * The name is user supplied data so don't trust it's size or 273 * that it is zero terminated. The name has priority. 274 * We are presently assuming that the sockaddr_in 275 * has not been replaced by a sockaddr_div, so we limit it 276 * to 16 bytes in total. the name is stuffed (if it exists) 277 * in the sin_zero[] field. 278 */ 279 while (*c++ && (len++ < sizeof(sin->sin_zero))); 280 if ((len > 0) && (len < sizeof(sin->sin_zero))) 281 m->m_pkthdr.rcvif = ifunit(sin->sin_zero); 282 } else { 283 ip_divert_cookie = 0; 284 } 285 286 /* Reinject packet into the system as incoming or outgoing */ 287 if (!sin || sin->sin_addr.s_addr == 0) { 288 /* 289 * Don't allow both user specified and setsockopt options, 290 * and don't allow packet length sizes that will crash 291 */ 292 if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) || 293 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { 294 error = EINVAL; 295 goto cantsend; 296 } 297 298 /* Convert fields to host order for ip_output() */ 299 ip->ip_len = ntohs(ip->ip_len); 300 ip->ip_off = ntohs(ip->ip_off); 301 302 /* Send packet to output processing */ 303 ipstat.ips_rawout++; /* XXX */ 304 error = ip_output(m, inp->inp_options, &inp->inp_route, 305 (so->so_options & SO_DONTROUTE) | 306 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 307 inp->inp_moptions); 308 } else { 309 struct ifaddr *ifa; 310 311 /* If no luck with the name above. check by IP address. */ 312 if (m->m_pkthdr.rcvif == NULL) { 313 /* 314 * Make sure there are no distractions 315 * for ifa_ifwithaddr. Clear the port and the ifname. 316 * Maybe zap all 8 bytes at once using a 64bit write? 317 */ 318 bzero(sin->sin_zero, sizeof(sin->sin_zero)); 319 /* *((u_int64_t *)sin->sin_zero) = 0; */ /* XXX ?? */ 320 sin->sin_port = 0; 321 if (!(ifa = ifa_ifwithaddr((struct sockaddr *) sin))) { 322 error = EADDRNOTAVAIL; 323 goto cantsend; 324 } 325 m->m_pkthdr.rcvif = ifa->ifa_ifp; 326 } 327 328 /* Send packet to input processing */ 329 ip_input(m); 330 } 331 332 /* paranoid: Reset for next time (and other packets) */ 333 /* almost definitly already done in the ipfw filter but.. */ 334 ip_divert_cookie = 0; 335 return error; 336 337 cantsend: 338 m_freem(m); 339 ip_divert_cookie = 0; 340 return error; 341 } 342 343 static int 344 div_attach(struct socket *so, int proto, struct thread *td) 345 { 346 struct inpcb *inp; 347 int error, s; 348 349 inp = sotoinpcb(so); 350 if (inp) 351 panic("div_attach"); 352 if (td && (error = suser(td)) != 0) 353 return error; 354 355 error = soreserve(so, div_sendspace, div_recvspace); 356 if (error) 357 return error; 358 s = splnet(); 359 error = in_pcballoc(so, &divcbinfo, td); 360 splx(s); 361 if (error) 362 return error; 363 inp = (struct inpcb *)so->so_pcb; 364 inp->inp_ip_p = proto; 365 inp->inp_vflag |= INP_IPV4; 366 inp->inp_flags |= INP_HDRINCL; 367 /* The socket is always "connected" because 368 we always know "where" to send the packet */ 369 so->so_state |= SS_ISCONNECTED; 370 return 0; 371 } 372 373 static int 374 div_detach(struct socket *so) 375 { 376 struct inpcb *inp; 377 378 inp = sotoinpcb(so); 379 if (inp == 0) 380 panic("div_detach"); 381 in_pcbdetach(inp); 382 return 0; 383 } 384 385 static int 386 div_abort(struct socket *so) 387 { 388 soisdisconnected(so); 389 return div_detach(so); 390 } 391 392 static int 393 div_disconnect(struct socket *so) 394 { 395 if ((so->so_state & SS_ISCONNECTED) == 0) 396 return ENOTCONN; 397 return div_abort(so); 398 } 399 400 static int 401 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 402 { 403 struct inpcb *inp; 404 int s; 405 int error; 406 407 s = splnet(); 408 inp = sotoinpcb(so); 409 /* in_pcbbind assumes that the socket is a sockaddr_in 410 * and in_pcbbind requires a valid address. Since divert 411 * sockets don't we need to make sure the address is 412 * filled in properly. 413 * XXX -- divert should not be abusing in_pcbind 414 * and should probably have its own family. 415 */ 416 if (nam->sa_family != AF_INET) { 417 error = EAFNOSUPPORT; 418 } else { 419 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 420 error = in_pcbbind(inp, nam, td); 421 } 422 splx(s); 423 return error; 424 } 425 426 static int 427 div_shutdown(struct socket *so) 428 { 429 socantsendmore(so); 430 return 0; 431 } 432 433 static int 434 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 435 struct mbuf *control, struct thread *td) 436 { 437 /* Packet must have a header (but that's about it) */ 438 if (m->m_len < sizeof (struct ip) && 439 (m = m_pullup(m, sizeof (struct ip))) == 0) { 440 ipstat.ips_toosmall++; 441 m_freem(m); 442 return EINVAL; 443 } 444 445 /* Send packet */ 446 return div_output(so, m, nam, control); 447 } 448 449 static int 450 div_pcblist(SYSCTL_HANDLER_ARGS) 451 { 452 int error, i, n, s; 453 struct inpcb *inp, **inp_list; 454 inp_gen_t gencnt; 455 struct xinpgen xig; 456 457 /* 458 * The process of preparing the TCB list is too time-consuming and 459 * resource-intensive to repeat twice on every request. 460 */ 461 if (req->oldptr == 0) { 462 n = divcbinfo.ipi_count; 463 req->oldidx = 2 * (sizeof xig) 464 + (n + n/8) * sizeof(struct xinpcb); 465 return 0; 466 } 467 468 if (req->newptr != 0) 469 return EPERM; 470 471 /* 472 * OK, now we're committed to doing something. 473 */ 474 s = splnet(); 475 gencnt = divcbinfo.ipi_gencnt; 476 n = divcbinfo.ipi_count; 477 splx(s); 478 479 xig.xig_len = sizeof xig; 480 xig.xig_count = n; 481 xig.xig_gen = gencnt; 482 xig.xig_sogen = so_gencnt; 483 error = SYSCTL_OUT(req, &xig, sizeof xig); 484 if (error) 485 return error; 486 487 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 488 if (inp_list == 0) 489 return ENOMEM; 490 491 s = splnet(); 492 for (inp = LIST_FIRST(divcbinfo.listhead), i = 0; inp && i < n; 493 inp = LIST_NEXT(inp, inp_list)) { 494 if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->td, inp)) 495 inp_list[i++] = inp; 496 } 497 splx(s); 498 n = i; 499 500 error = 0; 501 for (i = 0; i < n; i++) { 502 inp = inp_list[i]; 503 if (inp->inp_gencnt <= gencnt) { 504 struct xinpcb xi; 505 xi.xi_len = sizeof xi; 506 /* XXX should avoid extra copy */ 507 bcopy(inp, &xi.xi_inp, sizeof *inp); 508 if (inp->inp_socket) 509 sotoxsocket(inp->inp_socket, &xi.xi_socket); 510 error = SYSCTL_OUT(req, &xi, sizeof xi); 511 } 512 } 513 if (!error) { 514 /* 515 * Give the user an updated idea of our state. 516 * If the generation differs from what we told 517 * her before, she knows that something happened 518 * while we were processing this request, and it 519 * might be necessary to retry. 520 */ 521 s = splnet(); 522 xig.xig_gen = divcbinfo.ipi_gencnt; 523 xig.xig_sogen = so_gencnt; 524 xig.xig_count = divcbinfo.ipi_count; 525 splx(s); 526 error = SYSCTL_OUT(req, &xig, sizeof xig); 527 } 528 free(inp_list, M_TEMP); 529 return error; 530 } 531 532 /* 533 * This is the wrapper function for in_setsockaddr. We just pass down 534 * the pcbinfo for in_setpeeraddr to lock. 535 */ 536 static int 537 div_sockaddr(struct socket *so, struct sockaddr **nam) 538 { 539 return (in_setsockaddr(so, nam, &divcbinfo)); 540 } 541 542 /* 543 * This is the wrapper function for in_setpeeraddr. We just pass down 544 * the pcbinfo for in_setpeeraddr to lock. 545 */ 546 static int 547 div_peeraddr(struct socket *so, struct sockaddr **nam) 548 { 549 return (in_setpeeraddr(so, nam, &divcbinfo)); 550 } 551 552 553 SYSCTL_DECL(_net_inet_divert); 554 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0, 555 div_pcblist, "S,xinpcb", "List of active divert sockets"); 556 557 struct pr_usrreqs div_usrreqs = { 558 div_abort, pru_accept_notsupp, div_attach, div_bind, 559 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, 560 div_disconnect, pru_listen_notsupp, div_peeraddr, pru_rcvd_notsupp, 561 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, 562 div_sockaddr, sosend, soreceive, sopoll 563 }; 564