ip_divert.c revision 34923
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 * $Id: ip_divert.c,v 1.21 1998/03/24 18:06:15 wollman Exp $ 34 */ 35 36#include "opt_inet.h" 37 38#ifndef INET 39#error IPDIVERT requires INET. 40#endif 41 42#include <sys/param.h> 43#include <sys/malloc.h> 44#include <sys/mbuf.h> 45#include <sys/socket.h> 46#include <sys/protosw.h> 47#include <sys/socketvar.h> 48#include <sys/systm.h> 49#include <sys/proc.h> 50 51#include <vm/vm_zone.h> 52 53#include <net/if.h> 54#include <net/route.h> 55 56#include <netinet/in.h> 57#include <netinet/in_systm.h> 58#include <netinet/ip.h> 59#include <netinet/in_pcb.h> 60#include <netinet/in_var.h> 61#include <netinet/ip_var.h> 62 63/* 64 * Divert sockets 65 */ 66 67/* 68 * Allocate enough space to hold a full IP packet 69 */ 70#define DIVSNDQ (65536 + 100) 71#define DIVRCVQ (65536 + 100) 72 73/* Global variables */ 74 75/* 76 * ip_input() and ip_output() set this secret value before calling us to 77 * let us know which divert port to divert a packet to; this is done so 78 * we can use the existing prototype for struct protosw's pr_input(). 79 * This is stored in host order. 80 */ 81u_short ip_divert_port; 82 83/* 84 * We set this value to a non-zero port number when we want the call to 85 * ip_fw_chk() in ip_input() or ip_output() to ignore ``divert <port>'' 86 * chain entries. This is stored in host order. 87 */ 88u_short ip_divert_ignore; 89 90/* Internal variables */ 91 92static struct inpcbhead divcb; 93static struct inpcbinfo divcbinfo; 94 95static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 96static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 97 98/* Optimization: have this preinitialized */ 99static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET }; 100 101/* Internal functions */ 102 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 nmbclusters / 4, ZONE_INTERRUPT, 0); 123} 124 125/* 126 * Setup generic address and protocol structures 127 * for div_input routine, then pass them along with 128 * mbuf chain. ip->ip_len is assumed to have had 129 * the header length (hlen) subtracted out already. 130 * We tell whether the packet was incoming or outgoing 131 * by seeing if hlen == 0, which is a hack. 132 */ 133void 134div_input(struct mbuf *m, int hlen) 135{ 136 struct ip *ip; 137 struct inpcb *inp; 138 struct socket *sa; 139 140 /* Sanity check */ 141 if (ip_divert_port == 0) 142 panic("div_input: port is 0"); 143 144 /* Assure header */ 145 if (m->m_len < sizeof(struct ip) && 146 (m = m_pullup(m, sizeof(struct ip))) == 0) { 147 return; 148 } 149 ip = mtod(m, struct ip *); 150 151 /* Record divert port */ 152 divsrc.sin_port = htons(ip_divert_port); 153 154 /* Restore packet header fields */ 155 ip->ip_len += hlen; 156 HTONS(ip->ip_len); 157 HTONS(ip->ip_off); 158 159 /* Record receive interface address, if any */ 160 divsrc.sin_addr.s_addr = 0; 161 if (hlen) { 162 struct ifaddr *ifa; 163 164#ifdef DIAGNOSTIC 165 /* Sanity check */ 166 if (!(m->m_flags & M_PKTHDR)) 167 panic("div_input: no pkt hdr"); 168#endif 169 170 /* More fields affected by ip_input() */ 171 HTONS(ip->ip_id); 172 173 /* Find IP address for recieve interface */ 174 for (ifa = m->m_pkthdr.rcvif->if_addrhead.tqh_first; 175 ifa != NULL; ifa = ifa->ifa_link.tqe_next) { 176 if (ifa->ifa_addr == NULL) 177 continue; 178 if (ifa->ifa_addr->sa_family != AF_INET) 179 continue; 180 divsrc.sin_addr = 181 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 182 break; 183 } 184 } 185 186 /* Put packet on socket queue, if any */ 187 sa = NULL; 188 for (inp = divcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) { 189 if (inp->inp_lport == htons(ip_divert_port)) 190 sa = inp->inp_socket; 191 } 192 if (sa) { 193 if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, 194 m, (struct mbuf *)0) == 0) 195 m_freem(m); 196 else 197 sorwakeup(sa); 198 } else { 199 m_freem(m); 200 ipstat.ips_noproto++; 201 ipstat.ips_delivered--; 202 } 203} 204 205/* 206 * Deliver packet back into the IP processing machinery. 207 * 208 * If no address specified, or address is 0.0.0.0, send to ip_output(); 209 * otherwise, send to ip_input() and mark as having been received on 210 * the interface with that address. 211 * 212 * If no address specified, or dest port is 0, allow packet to divert 213 * back to this socket; otherwise, don't. 214 */ 215static int 216div_output(so, m, addr, control) 217 struct socket *so; 218 register struct mbuf *m; 219 struct sockaddr *addr; 220 struct mbuf *control; 221{ 222 register struct inpcb *const inp = sotoinpcb(so); 223 register struct ip *const ip = mtod(m, struct ip *); 224 struct sockaddr_in *sin = NULL; 225 int error = 0; 226 227 if (control) 228 m_freem(control); /* XXX */ 229 if (addr) 230 sin = (struct sockaddr_in *)addr; 231 232 /* Loopback avoidance option */ 233 ip_divert_ignore = ntohs(inp->inp_lport); 234 235 /* Reinject packet into the system as incoming or outgoing */ 236 if (!sin || sin->sin_addr.s_addr == 0) { 237 /* Don't allow both user specified and setsockopt options, 238 and don't allow packet length sizes that will crash */ 239 if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) || 240 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { 241 error = EINVAL; 242 goto cantsend; 243 } 244 245 /* Convert fields to host order for ip_output() */ 246 NTOHS(ip->ip_len); 247 NTOHS(ip->ip_off); 248 249 /* Send packet to output processing */ 250 ipstat.ips_rawout++; /* XXX */ 251 error = ip_output(m, inp->inp_options, &inp->inp_route, 252 (so->so_options & SO_DONTROUTE) | 253 IP_ALLOWBROADCAST | IP_RAWOUTPUT, inp->inp_moptions); 254 } else { 255 struct ifaddr *ifa; 256 257 /* Find receive interface with the given IP address */ 258 sin->sin_port = 0; 259 if ((ifa = ifa_ifwithaddr((struct sockaddr *) sin)) == 0) { 260 error = EADDRNOTAVAIL; 261 goto cantsend; 262 } 263 m->m_pkthdr.rcvif = ifa->ifa_ifp; 264 265 /* Send packet to input processing */ 266 ip_input(m); 267 } 268 269 /* Reset for next time (and other packets) */ 270 ip_divert_ignore = 0; 271 return error; 272 273cantsend: 274 ip_divert_ignore = 0; 275 m_freem(m); 276 return error; 277} 278 279static int 280div_attach(struct socket *so, int proto, struct proc *p) 281{ 282 struct inpcb *inp; 283 int error, s; 284 285 inp = sotoinpcb(so); 286 if (inp) 287 panic("div_attach"); 288 if (p && (error = suser(p->p_ucred, &p->p_acflag)) != 0) 289 return error; 290 291 s = splnet(); 292 error = in_pcballoc(so, &divcbinfo, p); 293 splx(s); 294 if (error) 295 return error; 296 error = soreserve(so, div_sendspace, div_recvspace); 297 if (error) 298 return error; 299 inp = (struct inpcb *)so->so_pcb; 300 inp->inp_ip_p = proto; 301 inp->inp_flags |= INP_HDRINCL; 302 /* The socket is always "connected" because 303 we always know "where" to send the packet */ 304 so->so_state |= SS_ISCONNECTED; 305 return 0; 306} 307 308static int 309div_detach(struct socket *so) 310{ 311 struct inpcb *inp; 312 313 inp = sotoinpcb(so); 314 if (inp == 0) 315 panic("div_detach"); 316 in_pcbdetach(inp); 317 return 0; 318} 319 320static int 321div_abort(struct socket *so) 322{ 323 soisdisconnected(so); 324 return div_detach(so); 325} 326 327static int 328div_disconnect(struct socket *so) 329{ 330 if ((so->so_state & SS_ISCONNECTED) == 0) 331 return ENOTCONN; 332 return div_abort(so); 333} 334 335static int 336div_bind(struct socket *so, struct sockaddr *nam, struct proc *p) 337{ 338 struct inpcb *inp; 339 int s; 340 int error; 341 342 s = splnet(); 343 inp = sotoinpcb(so); 344 error = in_pcbbind(inp, nam, p); 345 splx(s); 346 return 0; 347} 348 349static int 350div_shutdown(struct socket *so) 351{ 352 socantsendmore(so); 353 return 0; 354} 355 356static int 357div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 358 struct mbuf *control, struct proc *p) 359{ 360 /* Packet must have a header (but that's about it) */ 361 if (m->m_len < sizeof (struct ip) || 362 (m = m_pullup(m, sizeof (struct ip))) == 0) { 363 ipstat.ips_toosmall++; 364 m_freem(m); 365 return EINVAL; 366 } 367 368 /* Send packet */ 369 return div_output(so, m, nam, control); 370} 371 372struct pr_usrreqs div_usrreqs = { 373 div_abort, pru_accept_notsupp, div_attach, div_bind, 374 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, 375 div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp, 376 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, 377 in_setsockaddr, sosend, soreceive, sopoll 378}; 379