ip_divert.c revision 96972
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 96972 2002-05-20 05:41:09Z tanimura $ 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/lock.h> 48#include <sys/malloc.h> 49#include <sys/mbuf.h> 50#include <sys/proc.h> 51#include <sys/protosw.h> 52#include <sys/signalvar.h> 53#include <sys/socket.h> 54#include <sys/socketvar.h> 55#include <sys/sx.h> 56#include <sys/sysctl.h> 57#include <sys/systm.h> 58 59#include <vm/uma.h> 60 61#include <net/if.h> 62#include <net/route.h> 63 64#include <netinet/in.h> 65#include <netinet/in_pcb.h> 66#include <netinet/in_systm.h> 67#include <netinet/in_var.h> 68#include <netinet/ip.h> 69#include <netinet/ip_var.h> 70 71/* 72 * Divert sockets 73 */ 74 75/* 76 * Allocate enough space to hold a full IP packet 77 */ 78#define DIVSNDQ (65536 + 100) 79#define DIVRCVQ (65536 + 100) 80 81/* 82 * A 16 bit cookie is passed to and from the user process. 83 * The user process can send it back to help the caller know 84 * something about where the packet originally came from. 85 * 86 * In the case of ipfw, then the cookie is the rule that sent 87 * us here. On reinjection is is the rule after which processing 88 * should continue. Leaving it the same will make processing start 89 * at the rule number after that which sent it here. Setting it to 90 * 0 will restart processing at the beginning. 91 * 92 * For divert_packet(), ip_divert_cookie is an input value only. 93 * For div_output(), ip_divert_cookie is an output value only. 94 */ 95u_int16_t ip_divert_cookie; 96 97/* Internal variables */ 98static struct inpcbhead divcb; 99static struct inpcbinfo divcbinfo; 100 101static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 102static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 103 104/* Optimization: have this preinitialized */ 105static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET }; 106 107/* Internal functions */ 108static int div_output(struct socket *so, 109 struct mbuf *m, struct sockaddr *addr, struct mbuf *control); 110 111/* 112 * Initialize divert connection block queue. 113 */ 114void 115div_init(void) 116{ 117 LIST_INIT(&divcb); 118 divcbinfo.listhead = &divcb; 119 /* 120 * XXX We don't use the hash list for divert IP, but it's easier 121 * to allocate a one entry hash list than it is to check all 122 * over the place for hashbase == NULL. 123 */ 124 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); 125 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask); 126 divcbinfo.ipi_zone = uma_zcreate("divcb", sizeof(struct inpcb), 127 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 128 uma_zone_set_max(divcbinfo.ipi_zone, maxsockets); 129} 130 131/* 132 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets 133 * with that protocol number to enter the system from the outside. 134 */ 135void 136div_input(struct mbuf *m, int off) 137{ 138 ipstat.ips_noproto++; 139 m_freem(m); 140} 141 142/* 143 * Divert a packet by passing it up to the divert socket at port 'port'. 144 * 145 * Setup generic address and protocol structures for div_input routine, 146 * then pass them along with mbuf chain. 147 */ 148void 149divert_packet(struct mbuf *m, int incoming, int port) 150{ 151 struct ip *ip; 152 struct inpcb *inp; 153 struct socket *sa; 154 u_int16_t nport; 155 156 /* Sanity check */ 157 KASSERT(port != 0, ("%s: port=0", __func__)); 158 159 /* Record and reset divert cookie */ 160 divsrc.sin_port = ip_divert_cookie; 161 ip_divert_cookie = 0; 162 163 /* Assure header */ 164 if (m->m_len < sizeof(struct ip) && 165 (m = m_pullup(m, sizeof(struct ip))) == 0) { 166 return; 167 } 168 ip = mtod(m, struct ip *); 169 170 /* 171 * Record receive interface address, if any. 172 * But only for incoming packets. 173 */ 174 divsrc.sin_addr.s_addr = 0; 175 if (incoming) { 176 struct ifaddr *ifa; 177 178 /* Sanity check */ 179 KASSERT((m->m_flags & M_PKTHDR), ("%s: !PKTHDR", __func__)); 180 181 /* Find IP address for receive interface */ 182 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 183 if (ifa->ifa_addr == NULL) 184 continue; 185 if (ifa->ifa_addr->sa_family != AF_INET) 186 continue; 187 divsrc.sin_addr = 188 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 189 break; 190 } 191 } 192 /* 193 * Record the incoming interface name whenever we have one. 194 */ 195 bzero(&divsrc.sin_zero, sizeof(divsrc.sin_zero)); 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 "%s%d", m->m_pkthdr.rcvif->if_name, 217 m->m_pkthdr.rcvif->if_unit); 218 } 219 220 /* Put packet on socket queue, if any */ 221 sa = NULL; 222 nport = htons((u_int16_t)port); 223 LIST_FOREACH(inp, &divcb, inp_list) { 224 if (inp->inp_lport == nport) 225 sa = inp->inp_socket; 226 } 227 if (sa) { 228 if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, 229 m, (struct mbuf *)0) == 0) 230 m_freem(m); 231 else { 232 SOCK_LOCK(sa); 233 sorwakeup(sa); 234 SOCK_UNLOCK(sa); 235 } 236 } else { 237 m_freem(m); 238 ipstat.ips_noproto++; 239 ipstat.ips_delivered--; 240 } 241} 242 243/* 244 * Deliver packet back into the IP processing machinery. 245 * 246 * If no address specified, or address is 0.0.0.0, send to ip_output(); 247 * otherwise, send to ip_input() and mark as having been received on 248 * the interface with that address. 249 */ 250static int 251div_output(so, m, addr, control) 252 struct socket *so; 253 register struct mbuf *m; 254 struct sockaddr *addr; 255 struct mbuf *control; 256{ 257 register struct inpcb *const inp = sotoinpcb(so); 258 register struct ip *const ip = mtod(m, struct ip *); 259 struct sockaddr_in *sin = (struct sockaddr_in *)addr; 260 int error = 0; 261 int soopts; 262 263 if (control) 264 m_freem(control); /* XXX */ 265 266 /* Loopback avoidance and state recovery */ 267 if (sin) { 268 int len = 0; 269 char *c = sin->sin_zero; 270 271 ip_divert_cookie = sin->sin_port; 272 273 /* 274 * Find receive interface with the given name or IP address. 275 * The name is user supplied data so don't trust it's size or 276 * that it is zero terminated. The name has priority. 277 * We are presently assuming that the sockaddr_in 278 * has not been replaced by a sockaddr_div, so we limit it 279 * to 16 bytes in total. the name is stuffed (if it exists) 280 * in the sin_zero[] field. 281 */ 282 while (*c++ && (len++ < sizeof(sin->sin_zero))); 283 if ((len > 0) && (len < sizeof(sin->sin_zero))) 284 m->m_pkthdr.rcvif = ifunit(sin->sin_zero); 285 } else { 286 ip_divert_cookie = 0; 287 } 288 289 /* Reinject packet into the system as incoming or outgoing */ 290 if (!sin || sin->sin_addr.s_addr == 0) { 291 /* 292 * Don't allow both user specified and setsockopt options, 293 * and don't allow packet length sizes that will crash 294 */ 295 if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) || 296 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { 297 error = EINVAL; 298 goto cantsend; 299 } 300 301 /* Convert fields to host order for ip_output() */ 302 ip->ip_len = ntohs(ip->ip_len); 303 ip->ip_off = ntohs(ip->ip_off); 304 305 /* Send packet to output processing */ 306 ipstat.ips_rawout++; /* XXX */ 307 SOCK_LOCK(so); 308 soopts = so->so_options & SO_DONTROUTE; 309 SOCK_UNLOCK(so); 310 error = ip_output(m, inp->inp_options, &inp->inp_route, 311 soopts | 312 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 313 inp->inp_moptions); 314 } else { 315 struct ifaddr *ifa; 316 317 /* If no luck with the name above. check by IP address. */ 318 if (m->m_pkthdr.rcvif == NULL) { 319 /* 320 * Make sure there are no distractions 321 * for ifa_ifwithaddr. Clear the port and the ifname. 322 * Maybe zap all 8 bytes at once using a 64bit write? 323 */ 324 bzero(sin->sin_zero, sizeof(sin->sin_zero)); 325 /* *((u_int64_t *)sin->sin_zero) = 0; */ /* XXX ?? */ 326 sin->sin_port = 0; 327 if (!(ifa = ifa_ifwithaddr((struct sockaddr *) sin))) { 328 error = EADDRNOTAVAIL; 329 goto cantsend; 330 } 331 m->m_pkthdr.rcvif = ifa->ifa_ifp; 332 } 333 334 /* Send packet to input processing */ 335 ip_input(m); 336 } 337 338 /* paranoid: Reset for next time (and other packets) */ 339 /* almost definitly already done in the ipfw filter but.. */ 340 ip_divert_cookie = 0; 341 return error; 342 343cantsend: 344 m_freem(m); 345 ip_divert_cookie = 0; 346 return error; 347} 348 349static int 350div_attach(struct socket *so, int proto, struct thread *td) 351{ 352 struct inpcb *inp; 353 int error, s; 354 355 inp = sotoinpcb(so); 356 if (inp) 357 panic("div_attach"); 358 if (td && (error = suser(td)) != 0) 359 return error; 360 361 error = soreserve(so, div_sendspace, div_recvspace); 362 if (error) 363 return error; 364 s = splnet(); 365 error = in_pcballoc(so, &divcbinfo, td); 366 splx(s); 367 if (error) 368 return error; 369 inp = (struct inpcb *)so->so_pcb; 370 inp->inp_ip_p = proto; 371 inp->inp_vflag |= INP_IPV4; 372 inp->inp_flags |= INP_HDRINCL; 373 /* The socket is always "connected" because 374 we always know "where" to send the packet */ 375 SOCK_LOCK(so); 376 so->so_state |= SS_ISCONNECTED; 377 SOCK_UNLOCK(so); 378 return 0; 379} 380 381static int 382div_detach(struct socket *so) 383{ 384 struct inpcb *inp; 385 386 inp = sotoinpcb(so); 387 if (inp == 0) 388 panic("div_detach"); 389 in_pcbdetach(inp); 390 return 0; 391} 392 393static int 394div_abort(struct socket *so) 395{ 396 SOCK_LOCK(so); 397 soisdisconnected(so); 398 SOCK_UNLOCK(so); 399 return div_detach(so); 400} 401 402static int 403div_disconnect(struct socket *so) 404{ 405 SOCK_LOCK(so); 406 if ((so->so_state & SS_ISCONNECTED) == 0) { 407 SOCK_UNLOCK(so); 408 return ENOTCONN; 409 } 410 SOCK_UNLOCK(so); 411 return div_abort(so); 412} 413 414static int 415div_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 416{ 417 struct inpcb *inp; 418 int s; 419 int error; 420 421 s = splnet(); 422 inp = sotoinpcb(so); 423 /* in_pcbbind assumes that the socket is a sockaddr_in 424 * and in_pcbbind requires a valid address. Since divert 425 * sockets don't we need to make sure the address is 426 * filled in properly. 427 * XXX -- divert should not be abusing in_pcbind 428 * and should probably have its own family. 429 */ 430 if (nam->sa_family != AF_INET) { 431 error = EAFNOSUPPORT; 432 } else { 433 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 434 error = in_pcbbind(inp, nam, td); 435 } 436 splx(s); 437 return error; 438} 439 440static int 441div_shutdown(struct socket *so) 442{ 443 socantsendmore(so); 444 return 0; 445} 446 447static int 448div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 449 struct mbuf *control, struct thread *td) 450{ 451 /* Packet must have a header (but that's about it) */ 452 if (m->m_len < sizeof (struct ip) && 453 (m = m_pullup(m, sizeof (struct ip))) == 0) { 454 ipstat.ips_toosmall++; 455 m_freem(m); 456 return EINVAL; 457 } 458 459 /* Send packet */ 460 return div_output(so, m, nam, control); 461} 462 463static int 464div_pcblist(SYSCTL_HANDLER_ARGS) 465{ 466 int error, i, n, s; 467 struct inpcb *inp, **inp_list; 468 inp_gen_t gencnt; 469 struct xinpgen xig; 470 471 /* 472 * The process of preparing the TCB list is too time-consuming and 473 * resource-intensive to repeat twice on every request. 474 */ 475 if (req->oldptr == 0) { 476 n = divcbinfo.ipi_count; 477 req->oldidx = 2 * (sizeof xig) 478 + (n + n/8) * sizeof(struct xinpcb); 479 return 0; 480 } 481 482 if (req->newptr != 0) 483 return EPERM; 484 485 /* 486 * OK, now we're committed to doing something. 487 */ 488 s = splnet(); 489 gencnt = divcbinfo.ipi_gencnt; 490 n = divcbinfo.ipi_count; 491 splx(s); 492 493 xig.xig_len = sizeof xig; 494 xig.xig_count = n; 495 xig.xig_gen = gencnt; 496 xig.xig_sogen = so_gencnt; 497 error = SYSCTL_OUT(req, &xig, sizeof xig); 498 if (error) 499 return error; 500 501 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); 502 if (inp_list == 0) 503 return ENOMEM; 504 505 s = splnet(); 506 for (inp = LIST_FIRST(divcbinfo.listhead), i = 0; inp && i < n; 507 inp = LIST_NEXT(inp, inp_list)) { 508 if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->td, inp)) 509 inp_list[i++] = inp; 510 } 511 splx(s); 512 n = i; 513 514 error = 0; 515 for (i = 0; i < n; i++) { 516 inp = inp_list[i]; 517 if (inp->inp_gencnt <= gencnt) { 518 struct xinpcb xi; 519 xi.xi_len = sizeof xi; 520 /* XXX should avoid extra copy */ 521 bcopy(inp, &xi.xi_inp, sizeof *inp); 522 if (inp->inp_socket) 523 sotoxsocket(inp->inp_socket, &xi.xi_socket); 524 error = SYSCTL_OUT(req, &xi, sizeof xi); 525 } 526 } 527 if (!error) { 528 /* 529 * Give the user an updated idea of our state. 530 * If the generation differs from what we told 531 * her before, she knows that something happened 532 * while we were processing this request, and it 533 * might be necessary to retry. 534 */ 535 s = splnet(); 536 xig.xig_gen = divcbinfo.ipi_gencnt; 537 xig.xig_sogen = so_gencnt; 538 xig.xig_count = divcbinfo.ipi_count; 539 splx(s); 540 error = SYSCTL_OUT(req, &xig, sizeof xig); 541 } 542 free(inp_list, M_TEMP); 543 return error; 544} 545 546SYSCTL_DECL(_net_inet_divert); 547SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0, 548 div_pcblist, "S,xinpcb", "List of active divert sockets"); 549 550struct pr_usrreqs div_usrreqs = { 551 div_abort, pru_accept_notsupp, div_attach, div_bind, 552 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, 553 div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp, 554 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, 555 in_setsockaddr, sosend, soreceive, sopoll 556}; 557