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: src/sys/netinet/ip_divert.c,v 1.42.2.6 2003/01/23 21:06:45 sam Exp $ 34 * $DragonFly: src/sys/netinet/ip_divert.c,v 1.35 2007/12/21 13:17:51 sephe Exp $ 35 */ 36 37 #include "opt_inet.h" 38 #include "opt_ipfw.h" 39 #include "opt_ipdivert.h" 40 #include "opt_ipsec.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/malloc.h> 49 #include <sys/mbuf.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 #include <sys/proc.h> 56 #include <sys/thread2.h> 57 #ifdef SMP 58 #include <sys/msgport.h> 59 #endif 60 61 #include <vm/vm_zone.h> 62 63 #include <net/if.h> 64 #include <net/route.h> 65 #ifdef SMP 66 #include <net/netmsg2.h> 67 #endif 68 69 #include <netinet/in.h> 70 #include <netinet/in_systm.h> 71 #include <netinet/ip.h> 72 #include <netinet/in_pcb.h> 73 #include <netinet/in_var.h> 74 #include <netinet/ip_var.h> 75 76 /* 77 * Divert sockets 78 */ 79 80 /* 81 * Allocate enough space to hold a full IP packet 82 */ 83 #define DIVSNDQ (65536 + 100) 84 #define DIVRCVQ (65536 + 100) 85 86 #define DIV_IS_OUTPUT(sin) ((sin) == NULL || (sin)->sin_addr.s_addr == 0) 87 88 #define DIV_OUTPUT 0x10000 89 #define DIV_INPUT 0x20000 90 91 /* 92 * Divert sockets work in conjunction with ipfw, see the divert(4) 93 * manpage for features. 94 * Internally, packets selected by ipfw in ip_input() or ip_output(), 95 * and never diverted before, are passed to the input queue of the 96 * divert socket with a given 'divert_port' number (as specified in 97 * the matching ipfw rule), and they are tagged with a 16 bit cookie 98 * (representing the rule number of the matching ipfw rule), which 99 * is passed to process reading from the socket. 100 * 101 * Packets written to the divert socket are again tagged with a cookie 102 * (usually the same as above) and a destination address. 103 * If the destination address is INADDR_ANY then the packet is 104 * treated as outgoing and sent to ip_output(), otherwise it is 105 * treated as incoming and sent to ip_input(). 106 * In both cases, the packet is tagged with the cookie. 107 * 108 * On reinjection, processing in ip_input() and ip_output() 109 * will be exactly the same as for the original packet, except that 110 * ipfw processing will start at the rule number after the one 111 * written in the cookie (so, tagging a packet with a cookie of 0 112 * will cause it to be effectively considered as a standard packet). 113 */ 114 115 /* Internal variables */ 116 static struct inpcbinfo divcbinfo; 117 118 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 119 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 120 121 /* 122 * Initialize divert connection block queue. 123 */ 124 void 125 div_init(void) 126 { 127 in_pcbinfo_init(&divcbinfo); 128 /* 129 * XXX We don't use the hash list for divert IP, but it's easier 130 * to allocate a one entry hash list than it is to check all 131 * over the place for hashbase == NULL. 132 */ 133 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); 134 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask); 135 divcbinfo.wildcardhashbase = hashinit(1, M_PCB, 136 &divcbinfo.wildcardhashmask); 137 divcbinfo.ipi_zone = zinit("divcb", sizeof(struct inpcb), 138 maxsockets, ZONE_INTERRUPT, 0); 139 } 140 141 /* 142 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets 143 * with that protocol number to enter the system from the outside. 144 */ 145 void 146 div_input(struct mbuf *m, ...) 147 { 148 ipstat.ips_noproto++; 149 m_freem(m); 150 } 151 152 struct lwkt_port * 153 div_soport(struct socket *so, struct sockaddr *nam, 154 struct mbuf **mptr, int req) 155 { 156 struct sockaddr_in *sin; 157 struct mbuf *m; 158 int dir; 159 160 /* Except for send(), everything happens on CPU0 */ 161 if (req != PRU_SEND) 162 return cpu0_soport(so, nam, mptr, req); 163 164 sin = (struct sockaddr_in *)nam; 165 m = *mptr; 166 M_ASSERTPKTHDR(m); 167 168 m->m_pkthdr.rcvif = NULL; 169 dir = DIV_IS_OUTPUT(sin) ? IP_MPORT_OUT : IP_MPORT_IN; 170 171 if (sin != NULL) { 172 int i; 173 174 /* 175 * Try locating the interface, if we originally had one. 176 * This is done even for outgoing packets, since for a 177 * forwarded packet, there must be an interface attached. 178 * 179 * Find receive interface with the given name, stuffed 180 * (if it exists) in the sin_zero[] field. 181 * The name is user supplied data so don't trust its size 182 * or that it is zero terminated. 183 */ 184 for (i = 0; sin->sin_zero[i] && i < sizeof(sin->sin_zero); i++) 185 ; 186 if (i > 0 && i < sizeof(sin->sin_zero)) 187 m->m_pkthdr.rcvif = ifunit(sin->sin_zero); 188 } 189 190 if (dir == IP_MPORT_IN && m->m_pkthdr.rcvif == NULL) { 191 /* 192 * No luck with the name, check by IP address. 193 * Clear the port and the ifname to make sure 194 * there are no distractions for ifa_ifwithaddr. 195 * 196 * Be careful not to trash sin->sin_port; it will 197 * be used later in div_output(). 198 */ 199 struct ifaddr *ifa; 200 u_short sin_port; 201 202 bzero(sin->sin_zero, sizeof(sin->sin_zero)); 203 sin_port = sin->sin_port; /* save */ 204 sin->sin_port = 0; 205 ifa = ifa_ifwithaddr((struct sockaddr *)sin); 206 if (ifa == NULL) { 207 m_freem(m); 208 *mptr = NULL; 209 return NULL; 210 } 211 sin->sin_port = sin_port; /* restore */ 212 m->m_pkthdr.rcvif = ifa->ifa_ifp; 213 } 214 215 return ip_mport(mptr, dir); 216 } 217 218 /* 219 * Divert a packet by passing it up to the divert socket at port 'port'. 220 * 221 * Setup generic address and protocol structures for div_input routine, 222 * then pass them along with mbuf chain. 223 */ 224 static void 225 div_packet(struct mbuf *m, int incoming, int port) 226 { 227 struct sockaddr_in divsrc = { sizeof divsrc, AF_INET }; 228 struct inpcb *inp; 229 struct socket *sa; 230 struct m_tag *mtag; 231 u_int16_t nport; 232 233 /* Locate the divert tag */ 234 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 235 divsrc.sin_port = *(u_int16_t *)m_tag_data(mtag); 236 237 /* 238 * Record receive interface address, if any. 239 * But only for incoming packets. 240 */ 241 divsrc.sin_addr.s_addr = 0; 242 if (incoming) { 243 struct ifaddr *ifa; 244 245 /* Find IP address for receive interface */ 246 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 247 if (ifa->ifa_addr == NULL) 248 continue; 249 if (ifa->ifa_addr->sa_family != AF_INET) 250 continue; 251 divsrc.sin_addr = 252 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 253 break; 254 } 255 } 256 /* 257 * Record the incoming interface name whenever we have one. 258 */ 259 if (m->m_pkthdr.rcvif) { 260 /* 261 * Hide the actual interface name in there in the 262 * sin_zero array. XXX This needs to be moved to a 263 * different sockaddr type for divert, e.g. 264 * sockaddr_div with multiple fields like 265 * sockaddr_dl. Presently we have only 7 bytes 266 * but that will do for now as most interfaces 267 * are 4 or less + 2 or less bytes for unit. 268 * There is probably a faster way of doing this, 269 * possibly taking it from the sockaddr_dl on the iface. 270 * This solves the problem of a P2P link and a LAN interface 271 * having the same address, which can result in the wrong 272 * interface being assigned to the packet when fed back 273 * into the divert socket. Theoretically if the daemon saves 274 * and re-uses the sockaddr_in as suggested in the man pages, 275 * this iface name will come along for the ride. 276 * (see div_output for the other half of this.) 277 */ 278 ksnprintf(divsrc.sin_zero, sizeof divsrc.sin_zero, 279 m->m_pkthdr.rcvif->if_xname); 280 } 281 282 /* Put packet on socket queue, if any */ 283 sa = NULL; 284 nport = htons((u_int16_t)port); 285 LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) { 286 if (inp->inp_flags & INP_PLACEMARKER) 287 continue; 288 if (inp->inp_lport == nport) 289 sa = inp->inp_socket; 290 } 291 if (sa) { 292 if (ssb_appendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, 293 (struct mbuf *)NULL) == 0) 294 m_freem(m); 295 else 296 sorwakeup(sa); 297 } else { 298 m_freem(m); 299 ipstat.ips_noproto++; 300 ipstat.ips_delivered--; 301 } 302 } 303 304 #ifdef SMP 305 static void 306 div_packet_handler(struct netmsg *nmsg) 307 { 308 struct netmsg_packet *nmp; 309 struct lwkt_msg *msg; 310 struct mbuf *m; 311 int port, incoming = 0; 312 313 nmp = (struct netmsg_packet *)nmsg; 314 m = nmp->nm_packet; 315 316 msg = &nmsg->nm_lmsg; 317 port = msg->u.ms_result32 & 0xffff; 318 if (msg->u.ms_result32 & DIV_INPUT) 319 incoming = 1; 320 321 div_packet(m, incoming, port); 322 } 323 #endif /* SMP */ 324 325 void 326 divert_packet(struct mbuf *m, int incoming, int port) 327 { 328 /* Sanity check */ 329 KASSERT(port != 0, ("%s: port=0", __func__)); 330 M_ASSERTPKTHDR(m); 331 332 /* Assure header */ 333 if (m->m_len < sizeof(struct ip) && 334 (m = m_pullup(m, sizeof(struct ip))) == NULL) 335 return; 336 337 /* Sanity check */ 338 KASSERT(m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL) != NULL, 339 ("%s no divert tag!", __func__)); 340 341 #ifdef SMP 342 if (mycpuid != 0) { 343 struct netmsg_packet *nmp; 344 struct lwkt_msg *msg; 345 346 nmp = &m->m_hdr.mh_netmsg; 347 netmsg_init(&nmp->nm_netmsg, &netisr_apanic_rport, 0, 348 div_packet_handler); 349 nmp->nm_packet = m; 350 351 msg = &nmp->nm_netmsg.nm_lmsg; 352 msg->u.ms_result32 = port; /* port is 16bits */ 353 if (incoming) 354 msg->u.ms_result32 |= DIV_INPUT; 355 else 356 msg->u.ms_result32 |= DIV_OUTPUT; 357 358 lwkt_sendmsg(cpu_portfn(0), &nmp->nm_netmsg.nm_lmsg); 359 } else 360 #endif 361 div_packet(m, incoming, port); 362 } 363 364 /* 365 * Deliver packet back into the IP processing machinery. 366 * 367 * If no address specified, or address is 0.0.0.0, send to ip_output(); 368 * otherwise, send to ip_input() and mark as having been received on 369 * the interface with that address. 370 */ 371 static int 372 div_output(struct socket *so, struct mbuf *m, 373 struct sockaddr_in *sin, struct mbuf *control) 374 { 375 int error = 0; 376 struct m_tag *mtag; 377 378 if (control) 379 m_freem(control); /* XXX */ 380 381 /* 382 * Prepare the tag for divert info. Note that a packet 383 * with a 0 tag in mh_data is effectively untagged, 384 * so we could optimize that case. 385 */ 386 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(u_int16_t), MB_DONTWAIT); 387 if (mtag == NULL) { 388 error = ENOBUFS; 389 goto cantsend; 390 } 391 m_tag_prepend(m, mtag); 392 393 /* Loopback avoidance and state recovery */ 394 if (sin) 395 *(u_int16_t *)m_tag_data(mtag) = sin->sin_port; 396 else 397 *(u_int16_t *)m_tag_data(mtag) = 0; 398 399 /* Reinject packet into the system as incoming or outgoing */ 400 if (DIV_IS_OUTPUT(sin)) { 401 struct ip *const ip = mtod(m, struct ip *); 402 403 /* Don't allow packet length sizes that will crash */ 404 if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) { 405 error = EINVAL; 406 goto cantsend; 407 } 408 409 /* Convert fields to host order for ip_output() */ 410 ip->ip_len = ntohs(ip->ip_len); 411 ip->ip_off = ntohs(ip->ip_off); 412 413 /* Send packet to output processing */ 414 ipstat.ips_rawout++; /* XXX */ 415 error = ip_output(m, NULL, NULL, 416 (so->so_options & SO_DONTROUTE) | 417 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 418 NULL, NULL); 419 } else { 420 ip_input(m); 421 } 422 return error; 423 424 cantsend: 425 m_freem(m); 426 return error; 427 } 428 429 static int 430 div_attach(struct socket *so, int proto, struct pru_attach_info *ai) 431 { 432 struct inpcb *inp; 433 int error; 434 435 inp = so->so_pcb; 436 if (inp) 437 panic("div_attach"); 438 if ((error = suser_cred(ai->p_ucred, NULL_CRED_OKAY)) != 0) 439 return error; 440 441 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit); 442 if (error) 443 return error; 444 error = in_pcballoc(so, &divcbinfo); 445 if (error) 446 return error; 447 inp = (struct inpcb *)so->so_pcb; 448 inp->inp_ip_p = proto; 449 inp->inp_vflag |= INP_IPV4; 450 inp->inp_flags |= INP_HDRINCL; 451 /* 452 * The socket is always "connected" because 453 * we always know "where" to send the packet. 454 */ 455 so->so_state |= SS_ISCONNECTED; 456 return 0; 457 } 458 459 static int 460 div_detach(struct socket *so) 461 { 462 struct inpcb *inp; 463 464 inp = so->so_pcb; 465 if (inp == NULL) 466 panic("div_detach"); 467 in_pcbdetach(inp); 468 return 0; 469 } 470 471 static int 472 div_abort(struct socket *so) 473 { 474 soisdisconnected(so); 475 return div_detach(so); 476 } 477 478 static int 479 div_disconnect(struct socket *so) 480 { 481 if (!(so->so_state & SS_ISCONNECTED)) 482 return ENOTCONN; 483 return div_abort(so); 484 } 485 486 static int 487 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 488 { 489 int error; 490 491 /* 492 * in_pcbbind assumes that nam is a sockaddr_in 493 * and in_pcbbind requires a valid address. Since divert 494 * sockets don't we need to make sure the address is 495 * filled in properly. 496 * XXX -- divert should not be abusing in_pcbind 497 * and should probably have its own family. 498 */ 499 if (nam->sa_family != AF_INET) { 500 error = EAFNOSUPPORT; 501 } else { 502 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 503 error = in_pcbbind(so->so_pcb, nam, td); 504 } 505 return error; 506 } 507 508 static int 509 div_shutdown(struct socket *so) 510 { 511 socantsendmore(so); 512 return 0; 513 } 514 515 static int 516 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 517 struct mbuf *control, struct thread *td) 518 { 519 /* Length check already done in ip_mport() */ 520 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf")); 521 522 /* Send packet */ 523 return div_output(so, m, (struct sockaddr_in *)nam, control); 524 } 525 526 SYSCTL_DECL(_net_inet_divert); 527 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 0, 528 in_pcblist_global, "S,xinpcb", "List of active divert sockets"); 529 530 struct pr_usrreqs div_usrreqs = { 531 .pru_abort = div_abort, 532 .pru_accept = pru_accept_notsupp, 533 .pru_attach = div_attach, 534 .pru_bind = div_bind, 535 .pru_connect = pru_connect_notsupp, 536 .pru_connect2 = pru_connect2_notsupp, 537 .pru_control = in_control, 538 .pru_detach = div_detach, 539 .pru_disconnect = div_disconnect, 540 .pru_listen = pru_listen_notsupp, 541 .pru_peeraddr = in_setpeeraddr, 542 .pru_rcvd = pru_rcvd_notsupp, 543 .pru_rcvoob = pru_rcvoob_notsupp, 544 .pru_send = div_send, 545 .pru_sense = pru_sense_null, 546 .pru_shutdown = div_shutdown, 547 .pru_sockaddr = in_setsockaddr, 548 .pru_sosend = sosend, 549 .pru_soreceive = soreceive, 550 .pru_sopoll = sopoll 551 }; 552