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 1.21 2005/02/17 14:00:00 joerg 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 57 #include <vm/vm_zone.h> 58 59 #include <net/if.h> 60 #include <net/route.h> 61 62 #include <netinet/in.h> 63 #include <netinet/in_systm.h> 64 #include <netinet/ip.h> 65 #include <netinet/in_pcb.h> 66 #include <netinet/in_var.h> 67 #include <netinet/ip_var.h> 68 69 /* 70 * Divert sockets 71 */ 72 73 /* 74 * Allocate enough space to hold a full IP packet 75 */ 76 #define DIVSNDQ (65536 + 100) 77 #define DIVRCVQ (65536 + 100) 78 79 /* 80 * Divert sockets work in conjunction with ipfw, see the divert(4) 81 * manpage for features. 82 * Internally, packets selected by ipfw in ip_input() or ip_output(), 83 * and never diverted before, are passed to the input queue of the 84 * divert socket with a given 'divert_port' number (as specified in 85 * the matching ipfw rule), and they are tagged with a 16 bit cookie 86 * (representing the rule number of the matching ipfw rule), which 87 * is passed to process reading from the socket. 88 * 89 * Packets written to the divert socket are again tagged with a cookie 90 * (usually the same as above) and a destination address. 91 * If the destination address is INADDR_ANY then the packet is 92 * treated as outgoing and sent to ip_output(), otherwise it is 93 * treated as incoming and sent to ip_input(). 94 * In both cases, the packet is tagged with the cookie. 95 * 96 * On reinjection, processing in ip_input() and ip_output() 97 * will be exactly the same as for the original packet, except that 98 * ipfw processing will start at the rule number after the one 99 * written in the cookie (so, tagging a packet with a cookie of 0 100 * will cause it to be effectively considered as a standard packet). 101 */ 102 103 /* Internal variables */ 104 static struct inpcbinfo divcbinfo; 105 106 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 107 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 108 109 /* 110 * Initialize divert connection block queue. 111 */ 112 void 113 div_init(void) 114 { 115 in_pcbinfo_init(&divcbinfo); 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.wildcardhashbase = hashinit(1, M_PCB, 124 &divcbinfo.wildcardhashmask); 125 divcbinfo.ipi_zone = zinit("divcb", sizeof(struct inpcb), 126 maxsockets, ZONE_INTERRUPT, 0); 127 } 128 129 /* 130 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets 131 * with that protocol number to enter the system from the outside. 132 */ 133 void 134 div_input(struct mbuf *m, ...) 135 { 136 ipstat.ips_noproto++; 137 m_freem(m); 138 } 139 140 /* 141 * Divert a packet by passing it up to the divert socket at port 'port'. 142 * 143 * Setup generic address and protocol structures for div_input routine, 144 * then pass them along with mbuf chain. 145 */ 146 void 147 divert_packet(struct mbuf *m, int incoming, int port, int rule) 148 { 149 struct sockaddr_in divsrc = { sizeof divsrc, AF_INET }; 150 struct ip *ip; 151 struct inpcb *inp; 152 struct socket *sa; 153 u_int16_t nport; 154 155 /* Sanity check */ 156 KASSERT(port != 0, ("%s: port=0", __func__)); 157 158 divsrc.sin_port = rule; /* record matching rule */ 159 160 /* Assure header */ 161 if (m->m_len < sizeof(struct ip) && 162 (m = m_pullup(m, sizeof(struct ip))) == NULL) 163 return; 164 ip = mtod(m, struct ip *); 165 166 /* 167 * Record receive interface address, if any. 168 * But only for incoming packets. 169 */ 170 divsrc.sin_addr.s_addr = 0; 171 if (incoming) { 172 struct ifaddr *ifa; 173 174 /* Sanity check */ 175 KASSERT((m->m_flags & M_PKTHDR), ("%s: !PKTHDR", __func__)); 176 177 /* Find IP address for receive interface */ 178 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 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 if (m->m_pkthdr.rcvif) { 192 /* 193 * Hide the actual interface name in there in the 194 * sin_zero array. XXX This needs to be moved to a 195 * different sockaddr type for divert, e.g. 196 * sockaddr_div with multiple fields like 197 * sockaddr_dl. Presently we have only 7 bytes 198 * but that will do for now as most interfaces 199 * are 4 or less + 2 or less bytes for unit. 200 * There is probably a faster way of doing this, 201 * possibly taking it from the sockaddr_dl on the iface. 202 * This solves the problem of a P2P link and a LAN interface 203 * having the same address, which can result in the wrong 204 * interface being assigned to the packet when fed back 205 * into the divert socket. Theoretically if the daemon saves 206 * and re-uses the sockaddr_in as suggested in the man pages, 207 * this iface name will come along for the ride. 208 * (see div_output for the other half of this.) 209 */ 210 snprintf(divsrc.sin_zero, sizeof divsrc.sin_zero, 211 m->m_pkthdr.rcvif->if_xname); 212 } 213 214 /* Put packet on socket queue, if any */ 215 sa = NULL; 216 nport = htons((u_int16_t)port); 217 LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) { 218 if (inp->inp_flags & INP_PLACEMARKER) 219 continue; 220 if (inp->inp_lport == nport) 221 sa = inp->inp_socket; 222 } 223 if (sa) { 224 if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, 225 (struct mbuf *)NULL) == 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(struct socket *so, struct mbuf *m, 245 struct sockaddr_in *sin, struct mbuf *control) 246 { 247 int error = 0; 248 struct m_hdr divert_tag; 249 250 /* 251 * Prepare the tag for divert info. Note that a packet 252 * with a 0 tag in mh_data is effectively untagged, 253 * so we could optimize that case. 254 */ 255 divert_tag.mh_type = MT_TAG; 256 divert_tag.mh_flags = PACKET_TAG_DIVERT; 257 divert_tag.mh_next = m; 258 divert_tag.mh_data = 0; /* the matching rule # */ 259 m->m_pkthdr.rcvif = NULL; /* XXX is it necessary ? */ 260 261 if (control) 262 m_freem(control); /* XXX */ 263 264 /* Loopback avoidance and state recovery */ 265 if (sin) { 266 int i; 267 268 divert_tag.mh_data = (caddr_t)(int)sin->sin_port; 269 /* 270 * Find receive interface with the given name, stuffed 271 * (if it exists) in the sin_zero[] field. 272 * The name is user supplied data so don't trust its size 273 * or that it is zero terminated. 274 */ 275 for (i = 0; sin->sin_zero[i] && i < sizeof sin->sin_zero; i++) 276 ; 277 if ( i > 0 && i < sizeof sin->sin_zero) 278 m->m_pkthdr.rcvif = ifunit(sin->sin_zero); 279 } 280 281 /* Reinject packet into the system as incoming or outgoing */ 282 if (!sin || sin->sin_addr.s_addr == 0) { 283 struct inpcb *const inp = so->so_pcb; 284 struct ip *const ip = mtod(m, struct ip *); 285 286 /* 287 * Don't allow both user specified and setsockopt options, 288 * and don't allow packet length sizes that will crash 289 */ 290 if (((ip->ip_hl != (sizeof *ip) >> 2) && inp->inp_options) || 291 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { 292 error = EINVAL; 293 goto cantsend; 294 } 295 296 /* Convert fields to host order for ip_output() */ 297 ip->ip_len = ntohs(ip->ip_len); 298 ip->ip_off = ntohs(ip->ip_off); 299 300 /* Send packet to output processing */ 301 ipstat.ips_rawout++; /* XXX */ 302 error = ip_output((struct mbuf *)&divert_tag, 303 inp->inp_options, &inp->inp_route, 304 (so->so_options & SO_DONTROUTE) | 305 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 306 inp->inp_moptions, NULL); 307 } else { 308 if (m->m_pkthdr.rcvif == NULL) { 309 /* 310 * No luck with the name, check by IP address. 311 * Clear the port and the ifname to make sure 312 * there are no distractions for ifa_ifwithaddr. 313 */ 314 struct ifaddr *ifa; 315 316 bzero(sin->sin_zero, sizeof sin->sin_zero); 317 sin->sin_port = 0; 318 ifa = ifa_ifwithaddr((struct sockaddr *) sin); 319 if (ifa == NULL) { 320 error = EADDRNOTAVAIL; 321 goto cantsend; 322 } 323 m->m_pkthdr.rcvif = ifa->ifa_ifp; 324 } 325 ip_input((struct mbuf *)&divert_tag); 326 } 327 328 return error; 329 330 cantsend: 331 m_freem(m); 332 return error; 333 } 334 335 static int 336 div_attach(struct socket *so, int proto, struct pru_attach_info *ai) 337 { 338 struct inpcb *inp; 339 int error, s; 340 341 inp = so->so_pcb; 342 if (inp) 343 panic("div_attach"); 344 if ((error = suser_cred(ai->p_ucred, NULL_CRED_OKAY)) != 0) 345 return error; 346 347 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit); 348 if (error) 349 return error; 350 s = splnet(); 351 error = in_pcballoc(so, &divcbinfo); 352 splx(s); 353 if (error) 354 return error; 355 inp = (struct inpcb *)so->so_pcb; 356 inp->inp_ip_p = proto; 357 inp->inp_vflag |= INP_IPV4; 358 inp->inp_flags |= INP_HDRINCL; 359 /* 360 * The socket is always "connected" because 361 * we always know "where" to send the packet. 362 */ 363 so->so_state |= SS_ISCONNECTED; 364 return 0; 365 } 366 367 static int 368 div_detach(struct socket *so) 369 { 370 struct inpcb *inp; 371 372 inp = so->so_pcb; 373 if (inp == NULL) 374 panic("div_detach"); 375 in_pcbdetach(inp); 376 return 0; 377 } 378 379 static int 380 div_abort(struct socket *so) 381 { 382 soisdisconnected(so); 383 return div_detach(so); 384 } 385 386 static int 387 div_disconnect(struct socket *so) 388 { 389 if (!(so->so_state & SS_ISCONNECTED)) 390 return ENOTCONN; 391 return div_abort(so); 392 } 393 394 static int 395 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 396 { 397 struct inpcb *inp; 398 int s; 399 int error; 400 401 s = splnet(); 402 inp = so->so_pcb; 403 /* in_pcbbind assumes that nam is a sockaddr_in 404 * and in_pcbbind requires a valid address. Since divert 405 * sockets don't we need to make sure the address is 406 * filled in properly. 407 * XXX -- divert should not be abusing in_pcbind 408 * and should probably have its own family. 409 */ 410 if (nam->sa_family != AF_INET) 411 error = EAFNOSUPPORT; 412 else { 413 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 414 error = in_pcbbind(inp, nam, td); 415 } 416 splx(s); 417 return error; 418 } 419 420 static int 421 div_shutdown(struct socket *so) 422 { 423 socantsendmore(so); 424 return 0; 425 } 426 427 static int 428 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 429 struct mbuf *control, struct thread *td) 430 { 431 /* Packet must have a header (but that's about it) */ 432 if (m->m_len < sizeof(struct ip) && 433 (m = m_pullup(m, sizeof(struct ip))) == NULL) { 434 ipstat.ips_toosmall++; 435 m_freem(m); 436 return EINVAL; 437 } 438 439 /* Send packet */ 440 return div_output(so, m, (struct sockaddr_in *)nam, control); 441 } 442 443 SYSCTL_DECL(_net_inet_divert); 444 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 0, 445 in_pcblist_global, "S,xinpcb", "List of active divert sockets"); 446 447 struct pr_usrreqs div_usrreqs = { 448 div_abort, pru_accept_notsupp, div_attach, div_bind, 449 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, 450 div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp, 451 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, 452 in_setsockaddr, sosend, soreceive, sopoll 453 }; 454