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 1.25 2005/06/17 19:12:20 dillon 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 58 #include <vm/vm_zone.h> 59 60 #include <net/if.h> 61 #include <net/route.h> 62 63 #include <netinet/in.h> 64 #include <netinet/in_systm.h> 65 #include <netinet/ip.h> 66 #include <netinet/in_pcb.h> 67 #include <netinet/in_var.h> 68 #include <netinet/ip_var.h> 69 70 /* 71 * Divert sockets 72 */ 73 74 /* 75 * Allocate enough space to hold a full IP packet 76 */ 77 #define DIVSNDQ (65536 + 100) 78 #define DIVRCVQ (65536 + 100) 79 80 /* 81 * Divert sockets work in conjunction with ipfw, see the divert(4) 82 * manpage for features. 83 * Internally, packets selected by ipfw in ip_input() or ip_output(), 84 * and never diverted before, are passed to the input queue of the 85 * divert socket with a given 'divert_port' number (as specified in 86 * the matching ipfw rule), and they are tagged with a 16 bit cookie 87 * (representing the rule number of the matching ipfw rule), which 88 * is passed to process reading from the socket. 89 * 90 * Packets written to the divert socket are again tagged with a cookie 91 * (usually the same as above) and a destination address. 92 * If the destination address is INADDR_ANY then the packet is 93 * treated as outgoing and sent to ip_output(), otherwise it is 94 * treated as incoming and sent to ip_input(). 95 * In both cases, the packet is tagged with the cookie. 96 * 97 * On reinjection, processing in ip_input() and ip_output() 98 * will be exactly the same as for the original packet, except that 99 * ipfw processing will start at the rule number after the one 100 * written in the cookie (so, tagging a packet with a cookie of 0 101 * will cause it to be effectively considered as a standard packet). 102 */ 103 104 /* Internal variables */ 105 static struct inpcbinfo divcbinfo; 106 107 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 108 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 109 110 /* 111 * Initialize divert connection block queue. 112 */ 113 void 114 div_init(void) 115 { 116 in_pcbinfo_init(&divcbinfo); 117 /* 118 * XXX We don't use the hash list for divert IP, but it's easier 119 * to allocate a one entry hash list than it is to check all 120 * over the place for hashbase == NULL. 121 */ 122 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); 123 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask); 124 divcbinfo.wildcardhashbase = hashinit(1, M_PCB, 125 &divcbinfo.wildcardhashmask); 126 divcbinfo.ipi_zone = zinit("divcb", sizeof(struct inpcb), 127 maxsockets, ZONE_INTERRUPT, 0); 128 } 129 130 /* 131 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets 132 * with that protocol number to enter the system from the outside. 133 */ 134 void 135 div_input(struct mbuf *m, ...) 136 { 137 ipstat.ips_noproto++; 138 m_freem(m); 139 } 140 141 /* 142 * Divert a packet by passing it up to the divert socket at port 'port'. 143 * 144 * Setup generic address and protocol structures for div_input routine, 145 * then pass them along with mbuf chain. 146 */ 147 void 148 divert_packet(struct mbuf *m, int incoming, int port) 149 { 150 struct sockaddr_in divsrc = { sizeof divsrc, AF_INET }; 151 struct ip *ip; 152 struct inpcb *inp; 153 struct socket *sa; 154 struct m_tag *mtag; 155 u_int16_t nport; 156 157 /* Sanity check */ 158 KASSERT(port != 0, ("%s: port=0", __func__)); 159 160 if ((mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL)) != NULL) 161 divsrc.sin_port = *(u_int16_t *)m_tag_data(mtag); 162 else 163 divsrc.sin_port = 0; 164 165 /* Assure header */ 166 if (m->m_len < sizeof(struct ip) && 167 (m = m_pullup(m, sizeof(struct ip))) == NULL) 168 return; 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 if (m->m_pkthdr.rcvif) { 197 /* 198 * Hide the actual interface name in there in the 199 * sin_zero array. XXX This needs to be moved to a 200 * different sockaddr type for divert, e.g. 201 * sockaddr_div with multiple fields like 202 * sockaddr_dl. Presently we have only 7 bytes 203 * but that will do for now as most interfaces 204 * are 4 or less + 2 or less bytes for unit. 205 * There is probably a faster way of doing this, 206 * possibly taking it from the sockaddr_dl on the iface. 207 * This solves the problem of a P2P link and a LAN interface 208 * having the same address, which can result in the wrong 209 * interface being assigned to the packet when fed back 210 * into the divert socket. Theoretically if the daemon saves 211 * and re-uses the sockaddr_in as suggested in the man pages, 212 * this iface name will come along for the ride. 213 * (see div_output for the other half of this.) 214 */ 215 snprintf(divsrc.sin_zero, sizeof divsrc.sin_zero, 216 m->m_pkthdr.rcvif->if_xname); 217 } 218 219 /* Put packet on socket queue, if any */ 220 sa = NULL; 221 nport = htons((u_int16_t)port); 222 LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) { 223 if (inp->inp_flags & INP_PLACEMARKER) 224 continue; 225 if (inp->inp_lport == nport) 226 sa = inp->inp_socket; 227 } 228 if (sa) { 229 if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, 230 (struct mbuf *)NULL) == 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(struct socket *so, struct mbuf *m, 250 struct sockaddr_in *sin, struct mbuf *control) 251 { 252 int error = 0; 253 struct m_tag *mtag; 254 255 /* 256 * Prepare the tag for divert info. Note that a packet 257 * with a 0 tag in mh_data is effectively untagged, 258 * so we could optimize that case. 259 */ 260 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(u_int16_t), M_NOWAIT); 261 if (mtag == NULL) { 262 error = ENOBUFS; 263 goto cantsend; 264 } 265 m_tag_prepend(m, mtag); 266 m->m_pkthdr.rcvif = NULL; /* XXX is it necessary ? */ 267 268 if (control) 269 m_freem(control); /* XXX */ 270 271 /* Loopback avoidance and state recovery */ 272 if (sin) { 273 int i; 274 275 *(u_int16_t *)m_tag_data(mtag) = sin->sin_port; 276 /* 277 * Find receive interface with the given name, stuffed 278 * (if it exists) in the sin_zero[] field. 279 * The name is user supplied data so don't trust its size 280 * or that it is zero terminated. 281 */ 282 for (i = 0; sin->sin_zero[i] && i < sizeof sin->sin_zero; i++) 283 ; 284 if ( i > 0 && i < sizeof sin->sin_zero) 285 m->m_pkthdr.rcvif = ifunit(sin->sin_zero); 286 } else { 287 *(u_int16_t *)m_tag_data(mtag) = 0; 288 } 289 290 /* Reinject packet into the system as incoming or outgoing */ 291 if (!sin || sin->sin_addr.s_addr == 0) { 292 struct inpcb *const inp = so->so_pcb; 293 struct ip *const ip = mtod(m, struct ip *); 294 295 /* 296 * Don't allow both user specified and setsockopt options, 297 * and don't allow packet length sizes that will crash 298 */ 299 if (((ip->ip_hl != (sizeof *ip) >> 2) && inp->inp_options) || 300 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { 301 error = EINVAL; 302 goto cantsend; 303 } 304 305 /* Convert fields to host order for ip_output() */ 306 ip->ip_len = ntohs(ip->ip_len); 307 ip->ip_off = ntohs(ip->ip_off); 308 309 /* Send packet to output processing */ 310 ipstat.ips_rawout++; /* XXX */ 311 error = ip_output(m, 312 inp->inp_options, &inp->inp_route, 313 (so->so_options & SO_DONTROUTE) | 314 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 315 inp->inp_moptions, NULL); 316 } else { 317 if (m->m_pkthdr.rcvif == NULL) { 318 /* 319 * No luck with the name, check by IP address. 320 * Clear the port and the ifname to make sure 321 * there are no distractions for ifa_ifwithaddr. 322 */ 323 struct ifaddr *ifa; 324 325 bzero(sin->sin_zero, sizeof sin->sin_zero); 326 sin->sin_port = 0; 327 ifa = ifa_ifwithaddr((struct sockaddr *) sin); 328 if (ifa == NULL) { 329 error = EADDRNOTAVAIL; 330 goto cantsend; 331 } 332 m->m_pkthdr.rcvif = ifa->ifa_ifp; 333 } 334 ip_input(m); 335 } 336 337 return error; 338 339 cantsend: 340 m_freem(m); 341 return error; 342 } 343 344 static int 345 div_attach(struct socket *so, int proto, struct pru_attach_info *ai) 346 { 347 struct inpcb *inp; 348 int error; 349 350 inp = so->so_pcb; 351 if (inp) 352 panic("div_attach"); 353 if ((error = suser_cred(ai->p_ucred, NULL_CRED_OKAY)) != 0) 354 return error; 355 356 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit); 357 if (error) 358 return error; 359 crit_enter(); 360 error = in_pcballoc(so, &divcbinfo); 361 crit_exit(); 362 if (error) 363 return error; 364 inp = (struct inpcb *)so->so_pcb; 365 inp->inp_ip_p = proto; 366 inp->inp_vflag |= INP_IPV4; 367 inp->inp_flags |= INP_HDRINCL; 368 /* 369 * The socket is always "connected" because 370 * we always know "where" to send the packet. 371 */ 372 so->so_state |= SS_ISCONNECTED; 373 return 0; 374 } 375 376 static int 377 div_detach(struct socket *so) 378 { 379 struct inpcb *inp; 380 381 inp = so->so_pcb; 382 if (inp == NULL) 383 panic("div_detach"); 384 in_pcbdetach(inp); 385 return 0; 386 } 387 388 static int 389 div_abort(struct socket *so) 390 { 391 soisdisconnected(so); 392 return div_detach(so); 393 } 394 395 static int 396 div_disconnect(struct socket *so) 397 { 398 if (!(so->so_state & SS_ISCONNECTED)) 399 return ENOTCONN; 400 return div_abort(so); 401 } 402 403 static int 404 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 405 { 406 struct inpcb *inp; 407 int error; 408 409 crit_enter(); 410 inp = so->so_pcb; 411 /* in_pcbbind assumes that nam 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, td); 423 } 424 crit_exit(); 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 thread *td) 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))) == NULL) { 442 ipstat.ips_toosmall++; 443 m_freem(m); 444 return EINVAL; 445 } 446 447 /* Send packet */ 448 return div_output(so, m, (struct sockaddr_in *)nam, control); 449 } 450 451 SYSCTL_DECL(_net_inet_divert); 452 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 0, 453 in_pcblist_global, "S,xinpcb", "List of active divert sockets"); 454 455 struct pr_usrreqs div_usrreqs = { 456 div_abort, pru_accept_notsupp, div_attach, div_bind, 457 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, 458 div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp, 459 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, 460 in_setsockaddr, sosend, soreceive, sopoll 461 }; 462