ip_divert.c revision 59909
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 59909 2000-05-02 23:53:46Z paul $ 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/malloc.h> 47#include <sys/mbuf.h> 48#include <sys/socket.h> 49#include <sys/protosw.h> 50#include <sys/socketvar.h> 51#include <sys/systm.h> 52#include <sys/proc.h> 53 54#include <vm/vm_zone.h> 55 56#include <net/if.h> 57#include <net/route.h> 58 59#include <netinet/in.h> 60#include <netinet/in_systm.h> 61#include <netinet/ip.h> 62#include <netinet/in_pcb.h> 63#include <netinet/in_var.h> 64#include <netinet/ip_var.h> 65 66/* 67 * Divert sockets 68 */ 69 70/* 71 * Allocate enough space to hold a full IP packet 72 */ 73#define DIVSNDQ (65536 + 100) 74#define DIVRCVQ (65536 + 100) 75 76/* 77 * A 16 bit cookie is passed to and from the user process. 78 * The user process can send it back to help the caller know 79 * something about where the packet originally came from. 80 * 81 * In the case of ipfw, then the cookie is the rule that sent 82 * us here. On reinjection is is the rule after which processing 83 * should continue. Leaving it the same will make processing start 84 * at the rule number after that which sent it here. Setting it to 85 * 0 will restart processing at the beginning. 86 * 87 * For divert_packet(), ip_divert_cookie is an input value only. 88 * For div_output(), ip_divert_cookie is an output value only. 89 */ 90u_int16_t ip_divert_cookie; 91 92/* Internal variables */ 93static struct inpcbhead divcb; 94static struct inpcbinfo divcbinfo; 95 96static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 97static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 98 99/* Optimization: have this preinitialized */ 100static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET }; 101 102/* Internal functions */ 103static int div_output(struct socket *so, 104 struct mbuf *m, struct sockaddr *addr, struct mbuf *control); 105 106/* 107 * Initialize divert connection block queue. 108 */ 109void 110div_init(void) 111{ 112 LIST_INIT(&divcb); 113 divcbinfo.listhead = &divcb; 114 /* 115 * XXX We don't use the hash list for divert IP, but it's easier 116 * to allocate a one entry hash list than it is to check all 117 * over the place for hashbase == NULL. 118 */ 119 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); 120 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask); 121 divcbinfo.ipi_zone = zinit("divcb", sizeof(struct inpcb), 122 maxsockets, ZONE_INTERRUPT, 0); 123} 124 125/* 126 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets 127 * with that protocol number to enter the system from the outside. 128 */ 129void 130div_input(struct mbuf *m, int off, int proto) 131{ 132 ipstat.ips_noproto++; 133 m_freem(m); 134} 135 136/* 137 * Divert a packet by passing it up to the divert socket at port 'port'. 138 * 139 * Setup generic address and protocol structures for div_input routine, 140 * then pass them along with mbuf chain. 141 */ 142void 143divert_packet(struct mbuf *m, int incoming, int port) 144{ 145 struct ip *ip; 146 struct inpcb *inp; 147 struct socket *sa; 148 u_int16_t nport; 149 150 /* Sanity check */ 151 KASSERT(port != 0, ("%s: port=0", __FUNCTION__)); 152 153 /* Record and reset divert cookie */ 154 divsrc.sin_port = ip_divert_cookie; 155 ip_divert_cookie = 0; 156 157 /* Assure header */ 158 if (m->m_len < sizeof(struct ip) && 159 (m = m_pullup(m, sizeof(struct ip))) == 0) { 160 return; 161 } 162 ip = mtod(m, struct ip *); 163 164 /* 165 * Record receive interface address, if any. 166 * But only for incoming packets. 167 */ 168 divsrc.sin_addr.s_addr = 0; 169 if (incoming) { 170 struct ifaddr *ifa; 171 172 /* Sanity check */ 173 KASSERT((m->m_flags & M_PKTHDR), ("%s: !PKTHDR", __FUNCTION__)); 174 175 /* Find IP address for receive interface */ 176 for (ifa = m->m_pkthdr.rcvif->if_addrhead.tqh_first; 177 ifa != NULL; ifa = ifa->ifa_link.tqe_next) { 178 if (ifa->ifa_addr == NULL) 179 continue; 180 if (ifa->ifa_addr->sa_family != AF_INET) 181 continue; 182 divsrc.sin_addr = 183 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 184 break; 185 } 186 } 187 /* 188 * Record the incoming interface name whenever we have one. 189 */ 190 bzero(&divsrc.sin_zero, sizeof(divsrc.sin_zero)); 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 "%s%d", m->m_pkthdr.rcvif->if_name, 212 m->m_pkthdr.rcvif->if_unit); 213 } 214 215 /* Put packet on socket queue, if any */ 216 sa = NULL; 217 nport = htons((u_int16_t)port); 218 for (inp = divcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) { 219 if (inp->inp_lport == nport) 220 sa = inp->inp_socket; 221 } 222 if (sa) { 223 if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, 224 m, (struct mbuf *)0) == 0) 225 m_freem(m); 226 else 227 sorwakeup(sa); 228 } else { 229 m_freem(m); 230 ipstat.ips_noproto++; 231 ipstat.ips_delivered--; 232 } 233} 234 235/* 236 * Deliver packet back into the IP processing machinery. 237 * 238 * If no address specified, or address is 0.0.0.0, send to ip_output(); 239 * otherwise, send to ip_input() and mark as having been received on 240 * the interface with that address. 241 */ 242static int 243div_output(so, m, addr, control) 244 struct socket *so; 245 register struct mbuf *m; 246 struct sockaddr *addr; 247 struct mbuf *control; 248{ 249 register struct inpcb *const inp = sotoinpcb(so); 250 register struct ip *const ip = mtod(m, struct ip *); 251 struct sockaddr_in *sin = (struct sockaddr_in *)addr; 252 int error = 0; 253 254 if (control) 255 m_freem(control); /* XXX */ 256 257 /* Loopback avoidance and state recovery */ 258 if (sin) { 259 int len = 0; 260 char *c = sin->sin_zero; 261 262 ip_divert_cookie = sin->sin_port; 263 264 /* 265 * Find receive interface with the given name or IP address. 266 * The name is user supplied data so don't trust it's size or 267 * that it is zero terminated. The name has priority. 268 * We are presently assuming that the sockaddr_in 269 * has not been replaced by a sockaddr_div, so we limit it 270 * to 16 bytes in total. the name is stuffed (if it exists) 271 * in the sin_zero[] field. 272 */ 273 while (*c++ && (len++ < sizeof(sin->sin_zero))); 274 if ((len > 0) && (len < sizeof(sin->sin_zero))) 275 m->m_pkthdr.rcvif = ifunit(sin->sin_zero); 276 } else { 277 ip_divert_cookie = 0; 278 } 279 280 /* Reinject packet into the system as incoming or outgoing */ 281 if (!sin || sin->sin_addr.s_addr == 0) { 282 /* 283 * Don't allow both user specified and setsockopt options, 284 * and don't allow packet length sizes that will crash 285 */ 286 if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) || 287 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { 288 error = EINVAL; 289 goto cantsend; 290 } 291 292 /* Convert fields to host order for ip_output() */ 293 NTOHS(ip->ip_len); 294 NTOHS(ip->ip_off); 295 296 /* Send packet to output processing */ 297 ipstat.ips_rawout++; /* XXX */ 298 error = ip_output(m, inp->inp_options, &inp->inp_route, 299 (so->so_options & SO_DONTROUTE) | 300 IP_ALLOWBROADCAST | IP_RAWOUTPUT, 301 inp->inp_moptions); 302 } else { 303 struct ifaddr *ifa; 304 305 /* If no luck with the name above. check by IP address. */ 306 if (m->m_pkthdr.rcvif == NULL) { 307 /* 308 * Make sure there are no distractions 309 * for ifa_ifwithaddr. Clear the port and the ifname. 310 * Maybe zap all 8 bytes at once using a 64bit write? 311 */ 312 bzero(sin->sin_zero, sizeof(sin->sin_zero)); 313 /* *((u_int64_t *)sin->sin_zero) = 0; */ /* XXX ?? */ 314 sin->sin_port = 0; 315 if (!(ifa = ifa_ifwithaddr((struct sockaddr *) sin))) { 316 error = EADDRNOTAVAIL; 317 goto cantsend; 318 } 319 m->m_pkthdr.rcvif = ifa->ifa_ifp; 320 } 321 322 /* Send packet to input processing */ 323 ip_input(m); 324 } 325 326 /* paranoid: Reset for next time (and other packets) */ 327 /* almost definitly already done in the ipfw filter but.. */ 328 ip_divert_cookie = 0; 329 return error; 330 331cantsend: 332 m_freem(m); 333 ip_divert_cookie = 0; 334 return error; 335} 336 337static int 338div_attach(struct socket *so, int proto, struct proc *p) 339{ 340 struct inpcb *inp; 341 int error, s; 342 343 inp = sotoinpcb(so); 344 if (inp) 345 panic("div_attach"); 346 if (p && (error = suser(p)) != 0) 347 return error; 348 349 error = soreserve(so, div_sendspace, div_recvspace); 350 if (error) 351 return error; 352 s = splnet(); 353 error = in_pcballoc(so, &divcbinfo, p); 354 splx(s); 355 if (error) 356 return error; 357 inp = (struct inpcb *)so->so_pcb; 358 inp->inp_ip_p = proto; 359 inp->inp_flags |= INP_HDRINCL; 360 /* The socket is always "connected" because 361 we always know "where" to send the packet */ 362 so->so_state |= SS_ISCONNECTED; 363#ifdef IPSEC 364 error = ipsec_init_policy(so, &inp->inp_sp); 365 if (error != 0) { 366 in_pcbdetach(inp); 367 return error; 368 } 369#endif /*IPSEC*/ 370 return 0; 371} 372 373static int 374div_detach(struct socket *so) 375{ 376 struct inpcb *inp; 377 378 inp = sotoinpcb(so); 379 if (inp == 0) 380 panic("div_detach"); 381 in_pcbdetach(inp); 382 return 0; 383} 384 385static int 386div_abort(struct socket *so) 387{ 388 soisdisconnected(so); 389 return div_detach(so); 390} 391 392static int 393div_disconnect(struct socket *so) 394{ 395 if ((so->so_state & SS_ISCONNECTED) == 0) 396 return ENOTCONN; 397 return div_abort(so); 398} 399 400static int 401div_bind(struct socket *so, struct sockaddr *nam, struct proc *p) 402{ 403 struct inpcb *inp; 404 int s; 405 int error; 406 407 s = splnet(); 408 inp = sotoinpcb(so); 409 /* in_pcbbind assumes that the socket is a sockaddr_in 410 * and in_pcbbind requires a valid address. Since divert 411 * sockets don't we need to make sure the address is 412 * filled in properly. 413 * XXX -- divert should not be abusing in_pcbind 414 * and should probably have its own family. 415 */ 416 if (nam->sa_family != AF_INET) { 417 error = EAFNOSUPPORT; 418 } else { 419 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; 420 error = in_pcbbind(inp, nam, p); 421 } 422 splx(s); 423 return 0; 424} 425 426static int 427div_shutdown(struct socket *so) 428{ 429 socantsendmore(so); 430 return 0; 431} 432 433static int 434div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 435 struct mbuf *control, struct proc *p) 436{ 437 /* Packet must have a header (but that's about it) */ 438 if (m->m_len < sizeof (struct ip) && 439 (m = m_pullup(m, sizeof (struct ip))) == 0) { 440 ipstat.ips_toosmall++; 441 m_freem(m); 442 return EINVAL; 443 } 444 445 /* Send packet */ 446 return div_output(so, m, nam, control); 447} 448 449struct pr_usrreqs div_usrreqs = { 450 div_abort, pru_accept_notsupp, div_attach, div_bind, 451 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, 452 div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp, 453 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, 454 in_setsockaddr, sosend, soreceive, sopoll 455}; 456