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/malloc.h> 48 #include <sys/mbuf.h> 49 #include <sys/proc.h> 50 #include <sys/socket.h> 51 #include <sys/protosw.h> 52 #include <sys/socketvar.h> 53 #include <sys/sysctl.h> 54 #include <sys/systm.h> 55 56 #include <vm/uma.h> 57 58 #include <net/if.h> 59 #include <net/route.h> 60 61 #include <netinet/in.h> 62 #include <netinet/in_systm.h> 63 #include <netinet/ip.h> 64 #include <netinet/in_pcb.h> 65 #include <netinet/in_var.h> 66 #include <netinet/ip_var.h> 67 68 /* 69 * Divert sockets 70 */ 71 72 /* 73 * Allocate enough space to hold a full IP packet 74 */ 75 #define DIVSNDQ (65536 + 100) 76 #define DIVRCVQ (65536 + 100) 77 78 /* 79 * A 16 bit cookie is passed to and from the user process. 80 * The user process can send it back to help the caller know 81 * something about where the packet originally came from. 82 * 83 * In the case of ipfw, then the cookie is the rule that sent 84 * us here. On reinjection is is the rule after which processing 85 * should continue. Leaving it the same will make processing start 86 * at the rule number after that which sent it here. Setting it to 87 * 0 will restart processing at the beginning. 88 * 89 * For divert_packet(), ip_divert_cookie is an input value only. 90 * For div_output(), ip_divert_cookie is an output value only. 91 */ 92 u_int16_t ip_divert_cookie; 93 94 /* Internal variables */ 95 static struct inpcbhead divcb; 96 static struct inpcbinfo divcbinfo; 97 98 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 99 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 100 101 /* Optimization: have this preinitialized */ 102 static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET }; 103 104 /* Internal functions */ 105 static int div_output(struct socket *so, 106 struct mbuf *m, struct sockaddr *addr, struct mbuf *control); 107 108 /* 109 * Initialize divert connection block queue. 110 */ 111 void 112 div_init(void) 113 { 114 LIST_INIT(&divcb); 115 divcbinfo.listhead = &divcb; 116 /* 117 * XXX We don't use the hash list for divert IP, but it's easier 118 * to allocate a one entry hash list than it is to check all 119 * over the place for hashbase == NULL. 120 */ 121 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); 122 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask); 123 divcbinfo.ipi_zone = uma_zcreate("divcb", sizeof(struct inpcb), 124 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 125 uma_zone_set_max(divcbinfo.ipi_zone, maxsockets); 126 } 127 128 /* 129 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets 130 * with that protocol number to enter the system from the outside. 131 */ 132 void 133 div_input(struct mbuf *m, int off) 134 { 135 ipstat.ips_noproto++; 136 m_freem(m); 137 } 138 139 /* 140 * Divert a packet by passing it up to the divert socket at port 'port'. 141 * 142 * Setup generic address and protocol structures for div_input routine, 143 * then pass them along with mbuf chain. 144 */ 145 void 146 divert_packet(struct mbuf *m, int incoming, int port) 147 { 148 struct ip *ip; 149 struct inpcb *inp; 150 struct socket *sa; 151 u_int16_t nport; 152 153 /* Sanity check */ 154 KASSERT(port != 0, ("%s: port=0", __func__)); 155 156 /* Record and reset divert cookie */ 157 divsrc.sin_port = ip_divert_cookie; 158 ip_divert_cookie = 0; 159 160 /* Assure header */ 161 if (m->m_len < sizeof(struct ip) && 162 (m = m_pullup(m, sizeof(struct ip))) == 0) { 163 return; 164 } 165 ip = mtod(m, struct ip *); 166 167 /* 168 * Record receive interface address, if any. 169 * But only for incoming packets. 170 */ 171 divsrc.sin_addr.s_addr = 0; 172 if (incoming) { 173 struct ifaddr *ifa; 174 175 /* Sanity check */ 176 KASSERT((m->m_flags & M_PKTHDR), ("%s: !PKTHDR", __func__)); 177 178 /* Find IP address for receive interface */ 179 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 180 if (ifa->ifa_addr == NULL) 181 continue; 182 if (ifa->ifa_addr->sa_family != AF_INET) 183 continue; 184 divsrc.sin_addr = 185 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 186 break; 187 } 188 } 189 /* 190 * Record the incoming interface name whenever we have one. 191 */ 192 bzero(&divsrc.sin_zero, sizeof(divsrc.sin_zero)); 193 if (m->m_pkthdr.rcvif) { 194 /* 195 * Hide the actual interface name in there in the 196 * sin_zero array. XXX This needs to be moved to a 197 * different sockaddr type for divert, e.g. 198 * sockaddr_div with multiple fields like 199 * sockaddr_dl. Presently we have only 7 bytes 200 * but that will do for now as most interfaces 201 * are 4 or less + 2 or less bytes for unit. 202 * There is probably a faster way of doing this, 203 * possibly taking it from the sockaddr_dl on the iface. 204 * This solves the problem of a P2P link and a LAN interface 205 * having the same address, which can result in the wrong 206 * interface being assigned to the packet when fed back 207 * into the divert socket. Theoretically if the daemon saves 208 * and re-uses the sockaddr_in as suggested in the man pages, 209 * this iface name will come along for the ride. 210 * (see div_output for the other half of this.) 211 */ 212 snprintf(divsrc.sin_zero, sizeof(divsrc.sin_zero), 213 "%s%d", m->m_pkthdr.rcvif->if_name, 214 m->m_pkthdr.rcvif->if_unit); 215 } 216 217 /* Put packet on socket queue, if any */ 218 sa = NULL; 219 nport = htons((u_int16_t)port); 220 LIST_FOREACH(inp, &divcb, inp_list) { 221 if (inp->inp_lport == nport) 222 sa = inp->inp_socket; 223 } 224 if (sa) { 225 if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, 226 m, (struct mbuf *)0) == 0) 227 m_freem(m); 228 else 229 sorwakeup(sa); 230 } else { 231 m_freem(m); 232 ipstat.ips_noproto++; 233 ipstat.ips_delivered--; 234 } 235 } 236 237 /* 238 * Deliver packet back into the IP processing machinery. 239 * 240 * If no address specified, or address is 0.0.0.0, send to ip_output(); 241 * otherwise, send to ip_input() and mark as having been received on 242 * the interface with that address. 243 */ 244 static int 245 div_output(so, m, addr, control) 246 struct socket *so; 247 register struct mbuf *m; 248 struct sockaddr *addr; 249 struct mbuf *control; 250 { 251 register struct inpcb *const inp = sotoinpcb(so); 252 register struct ip *const ip = mtod(m, struct ip *); 253 struct sockaddr_in *sin = (struct sockaddr_in *)addr; 254 int error = 0; 255 256 if (control) 257 m_freem(control); /* XXX */ 258 259 /* Loopback avoidance and state recovery */ 260 if (sin) { 261 int len = 0; 262 char *c = sin->sin_zero; 263 264 ip_divert_cookie = sin->sin_port; 265 266 /* 267 * Find receive interface with the given name or IP address. 268 * The name is user supplied data so don't trust it's size or 269 * that it is zero terminated. The name has priority. 270 * We are presently assuming that the sockaddr_in 271 * has not been replaced by a sockaddr_div, so we limit it 272 * to 16 bytes in total. the name is stuffed (if it exists) 273 * in the sin_zero[] field. 274 */ 275 while (*c++ && (len++ < sizeof(sin->sin_zero))); 276 if ((len > 0) && (len < sizeof(sin->sin_zero))) 277 m->m_pkthdr.rcvif = ifunit(sin->sin_zero); 278 } else { 279 ip_divert_cookie = 0; 280 } 281 282 /* Reinject packet into the system as incoming or outgoing */ 283 if (!sin || sin->sin_addr.s_addr == 0) { 284 /* 285 * Don't allow both user specified and setsockopt options, 286 * and don't allow packet length sizes that will crash 287 */ 288 if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) || 289 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { 290 error = EINVAL; 291 goto cantsend; 292 } 293 294 /* Convert fields to host order for ip_output() */ 295 ip->ip_len = ntohs(ip->ip_len); 296 ip->ip_off = ntohs(ip->ip_off); 297 298 /* Send packet to output processing */ 299 ipstat.ips_rawout++; /* XXX */ 300 error = ip_output(m, inp->inp_options, &inp->inp_route, 301 (so->so_options & SO_DONTROUTE) | 302 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 303 inp->inp_moptions); 304 } else { 305 struct ifaddr *ifa; 306 307 /* If no luck with the name above. check by IP address. */ 308 if (m->m_pkthdr.rcvif == NULL) { 309 /* 310 * Make sure there are no distractions 311 * for ifa_ifwithaddr. Clear the port and the ifname. 312 * Maybe zap all 8 bytes at once using a 64bit write? 313 */ 314 bzero(sin->sin_zero, sizeof(sin->sin_zero)); 315 /* *((u_int64_t *)sin->sin_zero) = 0; */ /* XXX ?? */ 316 sin->sin_port = 0; 317 if (!(ifa = ifa_ifwithaddr((struct sockaddr *) sin))) { 318 error = EADDRNOTAVAIL; 319 goto cantsend; 320 } 321 m->m_pkthdr.rcvif = ifa->ifa_ifp; 322 } 323 324 /* Send packet to input processing */ 325 ip_input(m); 326 } 327 328 /* paranoid: Reset for next time (and other packets) */ 329 /* almost definitly already done in the ipfw filter but.. */ 330 ip_divert_cookie = 0; 331 return error; 332 333 cantsend: 334 m_freem(m); 335 ip_divert_cookie = 0; 336 return error; 337 } 338 339 static int 340 div_attach(struct socket *so, int proto, struct thread *td) 341 { 342 struct inpcb *inp; 343 int error, s; 344 345 inp = sotoinpcb(so); 346 if (inp) 347 panic("div_attach"); 348 if (td && (error = suser_td(td)) != 0) 349 return error; 350 351 error = soreserve(so, div_sendspace, div_recvspace); 352 if (error) 353 return error; 354 s = splnet(); 355 error = in_pcballoc(so, &divcbinfo, td); 356 splx(s); 357 if (error) 358 return error; 359 inp = (struct inpcb *)so->so_pcb; 360 inp->inp_ip_p = proto; 361 inp->inp_vflag |= INP_IPV4; 362 inp->inp_flags |= INP_HDRINCL; 363 /* The socket is always "connected" because 364 we always know "where" to send the packet */ 365 so->so_state |= SS_ISCONNECTED; 366 return 0; 367 } 368 369 static int 370 div_detach(struct socket *so) 371 { 372 struct inpcb *inp; 373 374 inp = sotoinpcb(so); 375 if (inp == 0) 376 panic("div_detach"); 377 in_pcbdetach(inp); 378 return 0; 379 } 380 381 static int 382 div_abort(struct socket *so) 383 { 384 soisdisconnected(so); 385 return div_detach(so); 386 } 387 388 static int 389 div_disconnect(struct socket *so) 390 { 391 if ((so->so_state & SS_ISCONNECTED) == 0) 392 return ENOTCONN; 393 return div_abort(so); 394 } 395 396 static int 397 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 398 { 399 struct inpcb *inp; 400 int s; 401 int error; 402 403 s = splnet(); 404 inp = sotoinpcb(so); 405 /* in_pcbbind assumes that the socket is a sockaddr_in 406 * and in_pcbbind requires a valid address. Since divert 407 * sockets don't we need to make sure the address is 408 * filled in properly. 409 * XXX -- divert should not be abusing in_pcbind 410 * and should probably have its own family. 411 */ 412 if (nam->sa_family != AF_INET) { 413 error = EAFNOSUPPORT; 414 } else { 415 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 416 error = in_pcbbind(inp, nam, td); 417 } 418 splx(s); 419 return error; 420 } 421 422 static int 423 div_shutdown(struct socket *so) 424 { 425 socantsendmore(so); 426 return 0; 427 } 428 429 static int 430 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 431 struct mbuf *control, struct thread *td) 432 { 433 /* Packet must have a header (but that's about it) */ 434 if (m->m_len < sizeof (struct ip) && 435 (m = m_pullup(m, sizeof (struct ip))) == 0) { 436 ipstat.ips_toosmall++; 437 m_freem(m); 438 return EINVAL; 439 } 440 441 /* Send packet */ 442 return div_output(so, m, nam, control); 443 } 444 445 static int 446 div_pcblist(SYSCTL_HANDLER_ARGS) 447 { 448 int error, i, n, s; 449 struct inpcb *inp, **inp_list; 450 inp_gen_t gencnt; 451 struct xinpgen xig; 452 453 /* 454 * The process of preparing the TCB list is too time-consuming and 455 * resource-intensive to repeat twice on every request. 456 */ 457 if (req->oldptr == 0) { 458 n = divcbinfo.ipi_count; 459 req->oldidx = 2 * (sizeof xig) 460 + (n + n/8) * sizeof(struct xinpcb); 461 return 0; 462 } 463 464 if (req->newptr != 0) 465 return EPERM; 466 467 /* 468 * OK, now we're committed to doing something. 469 */ 470 s = splnet(); 471 gencnt = divcbinfo.ipi_gencnt; 472 n = divcbinfo.ipi_count; 473 splx(s); 474 475 xig.xig_len = sizeof xig; 476 xig.xig_count = n; 477 xig.xig_gen = gencnt; 478 xig.xig_sogen = so_gencnt; 479 error = SYSCTL_OUT(req, &xig, sizeof xig); 480 if (error) 481 return error; 482 483 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 484 if (inp_list == 0) 485 return ENOMEM; 486 487 s = splnet(); 488 for (inp = LIST_FIRST(divcbinfo.listhead), i = 0; inp && i < n; 489 inp = LIST_NEXT(inp, inp_list)) { 490 if (inp->inp_gencnt <= gencnt && !prison_xinpcb( 491 req->td->td_proc, inp)) 492 inp_list[i++] = inp; 493 } 494 splx(s); 495 n = i; 496 497 error = 0; 498 for (i = 0; i < n; i++) { 499 inp = inp_list[i]; 500 if (inp->inp_gencnt <= gencnt) { 501 struct xinpcb xi; 502 xi.xi_len = sizeof xi; 503 /* XXX should avoid extra copy */ 504 bcopy(inp, &xi.xi_inp, sizeof *inp); 505 if (inp->inp_socket) 506 sotoxsocket(inp->inp_socket, &xi.xi_socket); 507 error = SYSCTL_OUT(req, &xi, sizeof xi); 508 } 509 } 510 if (!error) { 511 /* 512 * Give the user an updated idea of our state. 513 * If the generation differs from what we told 514 * her before, she knows that something happened 515 * while we were processing this request, and it 516 * might be necessary to retry. 517 */ 518 s = splnet(); 519 xig.xig_gen = divcbinfo.ipi_gencnt; 520 xig.xig_sogen = so_gencnt; 521 xig.xig_count = divcbinfo.ipi_count; 522 splx(s); 523 error = SYSCTL_OUT(req, &xig, sizeof xig); 524 } 525 free(inp_list, M_TEMP); 526 return error; 527 } 528 529 SYSCTL_DECL(_net_inet_divert); 530 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0, 531 div_pcblist, "S,xinpcb", "List of active divert sockets"); 532 533 struct pr_usrreqs div_usrreqs = { 534 div_abort, pru_accept_notsupp, div_attach, div_bind, 535 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, 536 div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp, 537 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, 538 in_setsockaddr, sosend, soreceive, sopoll 539 }; 540