ip_divert.c revision 64192
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: head/sys/netinet/ip_divert.c 64192 2000-08-03 14:09:52Z ru $ 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#include <sys/proc.h> 55 56#include <vm/vm_zone.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 */ 92u_int16_t ip_divert_cookie; 93 94/* Internal variables */ 95static struct inpcbhead divcb; 96static struct inpcbinfo divcbinfo; 97 98static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 99static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 100 101/* Optimization: have this preinitialized */ 102static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET }; 103 104/* Internal functions */ 105static 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 */ 111void 112div_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 = zinit("divcb", sizeof(struct inpcb), 124 maxsockets, ZONE_INTERRUPT, 0); 125} 126 127/* 128 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets 129 * with that protocol number to enter the system from the outside. 130 */ 131void 132div_input(struct mbuf *m, int off, int proto) 133{ 134 ipstat.ips_noproto++; 135 m_freem(m); 136} 137 138/* 139 * Divert a packet by passing it up to the divert socket at port 'port'. 140 * 141 * Setup generic address and protocol structures for div_input routine, 142 * then pass them along with mbuf chain. 143 */ 144void 145divert_packet(struct mbuf *m, int incoming, int port) 146{ 147 struct ip *ip; 148 struct inpcb *inp; 149 struct socket *sa; 150 u_int16_t nport; 151 152 /* Sanity check */ 153 KASSERT(port != 0, ("%s: port=0", __FUNCTION__)); 154 155 /* Record and reset divert cookie */ 156 divsrc.sin_port = ip_divert_cookie; 157 ip_divert_cookie = 0; 158 159 /* Assure header */ 160 if (m->m_len < sizeof(struct ip) && 161 (m = m_pullup(m, sizeof(struct ip))) == 0) { 162 return; 163 } 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", __FUNCTION__)); 176 177 /* Find IP address for receive interface */ 178 for (ifa = m->m_pkthdr.rcvif->if_addrhead.tqh_first; 179 ifa != NULL; ifa = ifa->ifa_link.tqe_next) { 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 for (inp = divcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) { 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 */ 244static int 245div_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 NTOHS(ip->ip_len); 296 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 333cantsend: 334 m_freem(m); 335 ip_divert_cookie = 0; 336 return error; 337} 338 339static int 340div_attach(struct socket *so, int proto, struct proc *p) 341{ 342 struct inpcb *inp; 343 int error, s; 344 345 inp = sotoinpcb(so); 346 if (inp) 347 panic("div_attach"); 348 if (p && (error = suser(p)) != 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, p); 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#ifdef IPSEC 367 error = ipsec_init_policy(so, &inp->inp_sp); 368 if (error != 0) { 369 in_pcbdetach(inp); 370 return error; 371 } 372#endif /*IPSEC*/ 373 return 0; 374} 375 376static int 377div_detach(struct socket *so) 378{ 379 struct inpcb *inp; 380 381 inp = sotoinpcb(so); 382 if (inp == 0) 383 panic("div_detach"); 384 in_pcbdetach(inp); 385 return 0; 386} 387 388static int 389div_abort(struct socket *so) 390{ 391 soisdisconnected(so); 392 return div_detach(so); 393} 394 395static int 396div_disconnect(struct socket *so) 397{ 398 if ((so->so_state & SS_ISCONNECTED) == 0) 399 return ENOTCONN; 400 return div_abort(so); 401} 402 403static int 404div_bind(struct socket *so, struct sockaddr *nam, struct proc *p) 405{ 406 struct inpcb *inp; 407 int s; 408 int error; 409 410 s = splnet(); 411 inp = sotoinpcb(so); 412 /* in_pcbbind assumes that the socket is a sockaddr_in 413 * and in_pcbbind requires a valid address. Since divert 414 * sockets don't we need to make sure the address is 415 * filled in properly. 416 * XXX -- divert should not be abusing in_pcbind 417 * and should probably have its own family. 418 */ 419 if (nam->sa_family != AF_INET) { 420 error = EAFNOSUPPORT; 421 } else { 422 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 423 error = in_pcbbind(inp, nam, p); 424 } 425 splx(s); 426 return 0; 427} 428 429static int 430div_shutdown(struct socket *so) 431{ 432 socantsendmore(so); 433 return 0; 434} 435 436static int 437div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 438 struct mbuf *control, struct proc *p) 439{ 440 /* Packet must have a header (but that's about it) */ 441 if (m->m_len < sizeof (struct ip) && 442 (m = m_pullup(m, sizeof (struct ip))) == 0) { 443 ipstat.ips_toosmall++; 444 m_freem(m); 445 return EINVAL; 446 } 447 448 /* Send packet */ 449 return div_output(so, m, nam, control); 450} 451 452static int 453div_pcblist(SYSCTL_HANDLER_ARGS) 454{ 455 int error, i, n, s; 456 struct inpcb *inp, **inp_list; 457 inp_gen_t gencnt; 458 struct xinpgen xig; 459 460 /* 461 * The process of preparing the TCB list is too time-consuming and 462 * resource-intensive to repeat twice on every request. 463 */ 464 if (req->oldptr == 0) { 465 n = divcbinfo.ipi_count; 466 req->oldidx = 2 * (sizeof xig) 467 + (n + n/8) * sizeof(struct xinpcb); 468 return 0; 469 } 470 471 if (req->newptr != 0) 472 return EPERM; 473 474 /* 475 * OK, now we're committed to doing something. 476 */ 477 s = splnet(); 478 gencnt = divcbinfo.ipi_gencnt; 479 n = divcbinfo.ipi_count; 480 splx(s); 481 482 xig.xig_len = sizeof xig; 483 xig.xig_count = n; 484 xig.xig_gen = gencnt; 485 xig.xig_sogen = so_gencnt; 486 error = SYSCTL_OUT(req, &xig, sizeof xig); 487 if (error) 488 return error; 489 490 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 491 if (inp_list == 0) 492 return ENOMEM; 493 494 s = splnet(); 495 for (inp = divcbinfo.listhead->lh_first, i = 0; inp && i < n; 496 inp = inp->inp_list.le_next) { 497 if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->p, inp)) 498 inp_list[i++] = inp; 499 } 500 splx(s); 501 n = i; 502 503 error = 0; 504 for (i = 0; i < n; i++) { 505 inp = inp_list[i]; 506 if (inp->inp_gencnt <= gencnt) { 507 struct xinpcb xi; 508 xi.xi_len = sizeof xi; 509 /* XXX should avoid extra copy */ 510 bcopy(inp, &xi.xi_inp, sizeof *inp); 511 if (inp->inp_socket) 512 sotoxsocket(inp->inp_socket, &xi.xi_socket); 513 error = SYSCTL_OUT(req, &xi, sizeof xi); 514 } 515 } 516 if (!error) { 517 /* 518 * Give the user an updated idea of our state. 519 * If the generation differs from what we told 520 * her before, she knows that something happened 521 * while we were processing this request, and it 522 * might be necessary to retry. 523 */ 524 s = splnet(); 525 xig.xig_gen = divcbinfo.ipi_gencnt; 526 xig.xig_sogen = so_gencnt; 527 xig.xig_count = divcbinfo.ipi_count; 528 splx(s); 529 error = SYSCTL_OUT(req, &xig, sizeof xig); 530 } 531 free(inp_list, M_TEMP); 532 return error; 533} 534 535SYSCTL_DECL(_net_inet_divert); 536SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0, 537 div_pcblist, "S,xinpcb", "List of active divert sockets"); 538 539struct pr_usrreqs div_usrreqs = { 540 div_abort, pru_accept_notsupp, div_attach, div_bind, 541 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, 542 div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp, 543 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, 544 in_setsockaddr, sosend, soreceive, sopoll 545}; 546