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/socket.h> 50 #include <sys/protosw.h> 51 #include <sys/socketvar.h> 52 #include <sys/sysctl.h> 53 #include <sys/systm.h> 54 55 #include <vm/vm_zone.h> 56 57 #include <net/if.h> 58 #include <net/route.h> 59 60 #include <netinet/in.h> 61 #include <netinet/in_systm.h> 62 #include <netinet/ip.h> 63 #include <netinet/in_pcb.h> 64 #include <netinet/in_var.h> 65 #include <netinet/ip_var.h> 66 67 /* 68 * Divert sockets 69 */ 70 71 /* 72 * Allocate enough space to hold a full IP packet 73 */ 74 #define DIVSNDQ (65536 + 100) 75 #define DIVRCVQ (65536 + 100) 76 77 /* 78 * A 16 bit cookie is passed to and from the user process. 79 * The user process can send it back to help the caller know 80 * something about where the packet originally came from. 81 * 82 * In the case of ipfw, then the cookie is the rule that sent 83 * us here. On reinjection is is the rule after which processing 84 * should continue. Leaving it the same will make processing start 85 * at the rule number after that which sent it here. Setting it to 86 * 0 will restart processing at the beginning. 87 * 88 * For divert_packet(), ip_divert_cookie is an input value only. 89 * For div_output(), ip_divert_cookie is an output value only. 90 */ 91 u_int16_t ip_divert_cookie; 92 93 /* Internal variables */ 94 static struct inpcbhead divcb; 95 static struct inpcbinfo divcbinfo; 96 97 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 98 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 99 100 /* Optimization: have this preinitialized */ 101 static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET }; 102 103 /* Internal functions */ 104 static int div_output(struct socket *so, 105 struct mbuf *m, struct sockaddr *addr, struct mbuf *control); 106 107 /* 108 * Initialize divert connection block queue. 109 */ 110 void 111 div_init(void) 112 { 113 LIST_INIT(&divcb); 114 divcbinfo.listhead = &divcb; 115 /* 116 * XXX We don't use the hash list for divert IP, but it's easier 117 * to allocate a one entry hash list than it is to check all 118 * over the place for hashbase == NULL. 119 */ 120 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); 121 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask); 122 divcbinfo.ipi_zone = zinit("divcb", sizeof(struct inpcb), 123 maxsockets, ZONE_INTERRUPT, 0); 124 } 125 126 /* 127 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets 128 * with that protocol number to enter the system from the outside. 129 */ 130 void 131 div_input(struct mbuf *m, int off, int proto) 132 { 133 ipstat.ips_noproto++; 134 m_freem(m); 135 } 136 137 /* 138 * Divert a packet by passing it up to the divert socket at port 'port'. 139 * 140 * Setup generic address and protocol structures for div_input routine, 141 * then pass them along with mbuf chain. 142 */ 143 void 144 divert_packet(struct mbuf *m, int incoming, int port) 145 { 146 struct ip *ip; 147 struct inpcb *inp; 148 struct socket *sa; 149 u_int16_t nport; 150 151 /* Sanity check */ 152 KASSERT(port != 0, ("%s: port=0", __FUNCTION__)); 153 154 /* Record and reset divert cookie */ 155 divsrc.sin_port = ip_divert_cookie; 156 ip_divert_cookie = 0; 157 158 /* Assure header */ 159 if (m->m_len < sizeof(struct ip) && 160 (m = m_pullup(m, sizeof(struct ip))) == 0) { 161 return; 162 } 163 ip = mtod(m, struct ip *); 164 165 /* 166 * Record receive interface address, if any. 167 * But only for incoming packets. 168 */ 169 divsrc.sin_addr.s_addr = 0; 170 if (incoming) { 171 struct ifaddr *ifa; 172 173 /* Sanity check */ 174 KASSERT((m->m_flags & M_PKTHDR), ("%s: !PKTHDR", __FUNCTION__)); 175 176 /* Find IP address for receive interface */ 177 for (ifa = m->m_pkthdr.rcvif->if_addrhead.tqh_first; 178 ifa != NULL; ifa = ifa->ifa_link.tqe_next) { 179 if (ifa->ifa_addr == NULL) 180 continue; 181 if (ifa->ifa_addr->sa_family != AF_INET) 182 continue; 183 divsrc.sin_addr = 184 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 185 break; 186 } 187 } 188 /* 189 * Record the incoming interface name whenever we have one. 190 */ 191 bzero(&divsrc.sin_zero, sizeof(divsrc.sin_zero)); 192 if (m->m_pkthdr.rcvif) { 193 /* 194 * Hide the actual interface name in there in the 195 * sin_zero array. XXX This needs to be moved to a 196 * different sockaddr type for divert, e.g. 197 * sockaddr_div with multiple fields like 198 * sockaddr_dl. Presently we have only 7 bytes 199 * but that will do for now as most interfaces 200 * are 4 or less + 2 or less bytes for unit. 201 * There is probably a faster way of doing this, 202 * possibly taking it from the sockaddr_dl on the iface. 203 * This solves the problem of a P2P link and a LAN interface 204 * having the same address, which can result in the wrong 205 * interface being assigned to the packet when fed back 206 * into the divert socket. Theoretically if the daemon saves 207 * and re-uses the sockaddr_in as suggested in the man pages, 208 * this iface name will come along for the ride. 209 * (see div_output for the other half of this.) 210 */ 211 snprintf(divsrc.sin_zero, sizeof(divsrc.sin_zero), 212 "%s%d", m->m_pkthdr.rcvif->if_name, 213 m->m_pkthdr.rcvif->if_unit); 214 } 215 216 /* Put packet on socket queue, if any */ 217 sa = NULL; 218 nport = htons((u_int16_t)port); 219 for (inp = divcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) { 220 if (inp->inp_lport == nport) 221 sa = inp->inp_socket; 222 } 223 if (sa) { 224 if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, 225 m, (struct mbuf *)0) == 0) 226 m_freem(m); 227 else 228 sorwakeup(sa); 229 } else { 230 m_freem(m); 231 ipstat.ips_noproto++; 232 ipstat.ips_delivered--; 233 } 234 } 235 236 /* 237 * Deliver packet back into the IP processing machinery. 238 * 239 * If no address specified, or address is 0.0.0.0, send to ip_output(); 240 * otherwise, send to ip_input() and mark as having been received on 241 * the interface with that address. 242 */ 243 static int 244 div_output(so, m, addr, control) 245 struct socket *so; 246 register struct mbuf *m; 247 struct sockaddr *addr; 248 struct mbuf *control; 249 { 250 register struct inpcb *const inp = sotoinpcb(so); 251 register struct ip *const ip = mtod(m, struct ip *); 252 struct sockaddr_in *sin = (struct sockaddr_in *)addr; 253 int error = 0; 254 255 if (control) 256 m_freem(control); /* XXX */ 257 258 /* Loopback avoidance and state recovery */ 259 if (sin) { 260 int len = 0; 261 char *c = sin->sin_zero; 262 263 ip_divert_cookie = sin->sin_port; 264 265 /* 266 * Find receive interface with the given name or IP address. 267 * The name is user supplied data so don't trust it's size or 268 * that it is zero terminated. The name has priority. 269 * We are presently assuming that the sockaddr_in 270 * has not been replaced by a sockaddr_div, so we limit it 271 * to 16 bytes in total. the name is stuffed (if it exists) 272 * in the sin_zero[] field. 273 */ 274 while (*c++ && (len++ < sizeof(sin->sin_zero))); 275 if ((len > 0) && (len < sizeof(sin->sin_zero))) 276 m->m_pkthdr.rcvif = ifunit(sin->sin_zero); 277 } else { 278 ip_divert_cookie = 0; 279 } 280 281 /* Reinject packet into the system as incoming or outgoing */ 282 if (!sin || sin->sin_addr.s_addr == 0) { 283 /* 284 * Don't allow both user specified and setsockopt options, 285 * and don't allow packet length sizes that will crash 286 */ 287 if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) || 288 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { 289 error = EINVAL; 290 goto cantsend; 291 } 292 293 /* Convert fields to host order for ip_output() */ 294 NTOHS(ip->ip_len); 295 NTOHS(ip->ip_off); 296 297 /* Send packet to output processing */ 298 ipstat.ips_rawout++; /* XXX */ 299 error = ip_output(m, inp->inp_options, &inp->inp_route, 300 (so->so_options & SO_DONTROUTE) | 301 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 302 inp->inp_moptions); 303 } else { 304 struct ifaddr *ifa; 305 306 /* If no luck with the name above. check by IP address. */ 307 if (m->m_pkthdr.rcvif == NULL) { 308 /* 309 * Make sure there are no distractions 310 * for ifa_ifwithaddr. Clear the port and the ifname. 311 * Maybe zap all 8 bytes at once using a 64bit write? 312 */ 313 bzero(sin->sin_zero, sizeof(sin->sin_zero)); 314 /* *((u_int64_t *)sin->sin_zero) = 0; */ /* XXX ?? */ 315 sin->sin_port = 0; 316 if (!(ifa = ifa_ifwithaddr((struct sockaddr *) sin))) { 317 error = EADDRNOTAVAIL; 318 goto cantsend; 319 } 320 m->m_pkthdr.rcvif = ifa->ifa_ifp; 321 } 322 323 /* Send packet to input processing */ 324 ip_input(m); 325 } 326 327 /* paranoid: Reset for next time (and other packets) */ 328 /* almost definitly already done in the ipfw filter but.. */ 329 ip_divert_cookie = 0; 330 return error; 331 332 cantsend: 333 m_freem(m); 334 ip_divert_cookie = 0; 335 return error; 336 } 337 338 static int 339 div_attach(struct socket *so, int proto, struct proc *p) 340 { 341 struct inpcb *inp; 342 int error, s; 343 344 inp = sotoinpcb(so); 345 if (inp) 346 panic("div_attach"); 347 if (p && (error = suser(p)) != 0) 348 return error; 349 350 error = soreserve(so, div_sendspace, div_recvspace); 351 if (error) 352 return error; 353 s = splnet(); 354 error = in_pcballoc(so, &divcbinfo, p); 355 splx(s); 356 if (error) 357 return error; 358 inp = (struct inpcb *)so->so_pcb; 359 inp->inp_ip_p = proto; 360 inp->inp_vflag |= INP_IPV4; 361 inp->inp_flags |= INP_HDRINCL; 362 /* The socket is always "connected" because 363 we always know "where" to send the packet */ 364 so->so_state |= SS_ISCONNECTED; 365 #ifdef IPSEC 366 error = ipsec_init_policy(so, &inp->inp_sp); 367 if (error != 0) { 368 in_pcbdetach(inp); 369 return error; 370 } 371 #endif /*IPSEC*/ 372 return 0; 373 } 374 375 static int 376 div_detach(struct socket *so) 377 { 378 struct inpcb *inp; 379 380 inp = sotoinpcb(so); 381 if (inp == 0) 382 panic("div_detach"); 383 in_pcbdetach(inp); 384 return 0; 385 } 386 387 static int 388 div_abort(struct socket *so) 389 { 390 soisdisconnected(so); 391 return div_detach(so); 392 } 393 394 static int 395 div_disconnect(struct socket *so) 396 { 397 if ((so->so_state & SS_ISCONNECTED) == 0) 398 return ENOTCONN; 399 return div_abort(so); 400 } 401 402 static int 403 div_bind(struct socket *so, struct sockaddr *nam, struct proc *p) 404 { 405 struct inpcb *inp; 406 int s; 407 int error; 408 409 s = splnet(); 410 inp = sotoinpcb(so); 411 /* in_pcbbind assumes that the socket is a sockaddr_in 412 * and in_pcbbind requires a valid address. Since divert 413 * sockets don't we need to make sure the address is 414 * filled in properly. 415 * XXX -- divert should not be abusing in_pcbind 416 * and should probably have its own family. 417 */ 418 if (nam->sa_family != AF_INET) { 419 error = EAFNOSUPPORT; 420 } else { 421 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 422 error = in_pcbbind(inp, nam, p); 423 } 424 splx(s); 425 return error; 426 } 427 428 static int 429 div_shutdown(struct socket *so) 430 { 431 socantsendmore(so); 432 return 0; 433 } 434 435 static int 436 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 437 struct mbuf *control, struct proc *p) 438 { 439 /* Packet must have a header (but that's about it) */ 440 if (m->m_len < sizeof (struct ip) && 441 (m = m_pullup(m, sizeof (struct ip))) == 0) { 442 ipstat.ips_toosmall++; 443 m_freem(m); 444 return EINVAL; 445 } 446 447 /* Send packet */ 448 return div_output(so, m, nam, control); 449 } 450 451 static int 452 div_pcblist(SYSCTL_HANDLER_ARGS) 453 { 454 int error, i, n, s; 455 struct inpcb *inp, **inp_list; 456 inp_gen_t gencnt; 457 struct xinpgen xig; 458 459 /* 460 * The process of preparing the TCB list is too time-consuming and 461 * resource-intensive to repeat twice on every request. 462 */ 463 if (req->oldptr == 0) { 464 n = divcbinfo.ipi_count; 465 req->oldidx = 2 * (sizeof xig) 466 + (n + n/8) * sizeof(struct xinpcb); 467 return 0; 468 } 469 470 if (req->newptr != 0) 471 return EPERM; 472 473 /* 474 * OK, now we're committed to doing something. 475 */ 476 s = splnet(); 477 gencnt = divcbinfo.ipi_gencnt; 478 n = divcbinfo.ipi_count; 479 splx(s); 480 481 xig.xig_len = sizeof xig; 482 xig.xig_count = n; 483 xig.xig_gen = gencnt; 484 xig.xig_sogen = so_gencnt; 485 error = SYSCTL_OUT(req, &xig, sizeof xig); 486 if (error) 487 return error; 488 489 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 490 if (inp_list == 0) 491 return ENOMEM; 492 493 s = splnet(); 494 for (inp = divcbinfo.listhead->lh_first, i = 0; inp && i < n; 495 inp = inp->inp_list.le_next) { 496 if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->p, inp)) 497 inp_list[i++] = inp; 498 } 499 splx(s); 500 n = i; 501 502 error = 0; 503 for (i = 0; i < n; i++) { 504 inp = inp_list[i]; 505 if (inp->inp_gencnt <= gencnt) { 506 struct xinpcb xi; 507 xi.xi_len = sizeof xi; 508 /* XXX should avoid extra copy */ 509 bcopy(inp, &xi.xi_inp, sizeof *inp); 510 if (inp->inp_socket) 511 sotoxsocket(inp->inp_socket, &xi.xi_socket); 512 error = SYSCTL_OUT(req, &xi, sizeof xi); 513 } 514 } 515 if (!error) { 516 /* 517 * Give the user an updated idea of our state. 518 * If the generation differs from what we told 519 * her before, she knows that something happened 520 * while we were processing this request, and it 521 * might be necessary to retry. 522 */ 523 s = splnet(); 524 xig.xig_gen = divcbinfo.ipi_gencnt; 525 xig.xig_sogen = so_gencnt; 526 xig.xig_count = divcbinfo.ipi_count; 527 splx(s); 528 error = SYSCTL_OUT(req, &xig, sizeof xig); 529 } 530 free(inp_list, M_TEMP); 531 return error; 532 } 533 534 SYSCTL_DECL(_net_inet_divert); 535 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0, 536 div_pcblist, "S,xinpcb", "List of active divert sockets"); 537 538 struct pr_usrreqs div_usrreqs = { 539 div_abort, pru_accept_notsupp, div_attach, div_bind, 540 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, 541 div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp, 542 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, 543 in_setsockaddr, sosend, soreceive, sopoll 544 }; 545