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 1.11 1997/06/01 15:58:44 peter Exp $ 34 */ 35 36 #include <sys/param.h> 37 #include <sys/queue.h> 38 #include <sys/malloc.h> 39 #include <sys/mbuf.h> 40 #include <sys/socket.h> 41 #include <sys/protosw.h> 42 #include <sys/socketvar.h> 43 #include <sys/errno.h> 44 #include <sys/systm.h> 45 #include <sys/proc.h> 46 47 #include <net/if.h> 48 #include <net/route.h> 49 50 #include <netinet/in.h> 51 #include <netinet/in_systm.h> 52 #include <netinet/ip.h> 53 #include <netinet/in_pcb.h> 54 #include <netinet/in_var.h> 55 #include <netinet/ip_var.h> 56 57 /* 58 * Divert sockets 59 */ 60 61 /* 62 * Allocate enough space to hold a full IP packet 63 */ 64 #define DIVSNDQ (65536 + 100) 65 #define DIVRCVQ (65536 + 100) 66 67 /* Global variables */ 68 69 /* 70 * ip_input() and ip_output() set this secret value before calling us to 71 * let us know which divert port to divert a packet to; this is done so 72 * we can use the existing prototype for struct protosw's pr_input(). 73 * This is stored in host order. 74 */ 75 u_short ip_divert_port; 76 77 /* 78 * We set this value to a non-zero port number when we want the call to 79 * ip_fw_chk() in ip_input() or ip_output() to ignore ``divert <port>'' 80 * chain entries. This is stored in host order. 81 */ 82 u_short ip_divert_ignore; 83 84 /* Internal variables */ 85 86 static struct inpcbhead divcb; 87 static struct inpcbinfo divcbinfo; 88 89 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ 90 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ 91 92 /* Optimization: have this preinitialized */ 93 static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET }; 94 95 /* Internal functions */ 96 97 static int div_output(struct socket *so, 98 struct mbuf *m, struct mbuf *addr, struct mbuf *control); 99 100 /* 101 * Initialize divert connection block queue. 102 */ 103 void 104 div_init(void) 105 { 106 LIST_INIT(&divcb); 107 divcbinfo.listhead = &divcb; 108 /* 109 * XXX We don't use the hash list for divert IP, but it's easier 110 * to allocate a one entry hash list than it is to check all 111 * over the place for hashbase == NULL. 112 */ 113 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); 114 } 115 116 /* 117 * Setup generic address and protocol structures 118 * for div_input routine, then pass them along with 119 * mbuf chain. ip->ip_len is assumed to have had 120 * the header length (hlen) subtracted out already. 121 * We tell whether the packet was incoming or outgoing 122 * by seeing if hlen == 0, which is a hack. 123 */ 124 void 125 div_input(struct mbuf *m, int hlen) 126 { 127 struct ip *ip; 128 struct inpcb *inp; 129 struct socket *sa; 130 131 /* Sanity check */ 132 if (ip_divert_port == 0) 133 panic("div_input: port is 0"); 134 135 /* Assure header */ 136 if (m->m_len < sizeof(struct ip) && 137 (m = m_pullup(m, sizeof(struct ip))) == 0) { 138 return; 139 } 140 ip = mtod(m, struct ip *); 141 142 /* Record divert port */ 143 divsrc.sin_port = htons(ip_divert_port); 144 145 /* Restore packet header fields */ 146 ip->ip_len += hlen; 147 HTONS(ip->ip_len); 148 HTONS(ip->ip_off); 149 150 /* Record receive interface address, if any */ 151 divsrc.sin_addr.s_addr = 0; 152 if (hlen) { 153 struct ifaddr *ifa; 154 155 #ifdef DIAGNOSTIC 156 /* Sanity check */ 157 if (!(m->m_flags & M_PKTHDR)) 158 panic("div_input: no pkt hdr"); 159 #endif 160 161 /* More fields affected by ip_input() */ 162 HTONS(ip->ip_id); 163 164 /* Find IP address for recieve interface */ 165 for (ifa = m->m_pkthdr.rcvif->if_addrhead.tqh_first; 166 ifa != NULL; ifa = ifa->ifa_link.tqe_next) { 167 if (ifa->ifa_addr == NULL) 168 continue; 169 if (ifa->ifa_addr->sa_family != AF_INET) 170 continue; 171 divsrc.sin_addr = 172 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; 173 break; 174 } 175 } 176 177 /* Put packet on socket queue, if any */ 178 sa = NULL; 179 for (inp = divcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) { 180 if (inp->inp_lport == htons(ip_divert_port)) 181 sa = inp->inp_socket; 182 } 183 if (sa) { 184 if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, 185 m, (struct mbuf *)0) == 0) 186 m_freem(m); 187 else 188 sorwakeup(sa); 189 } else { 190 m_freem(m); 191 ipstat.ips_noproto++; 192 ipstat.ips_delivered--; 193 } 194 } 195 196 /* 197 * Deliver packet back into the IP processing machinery. 198 * 199 * If no address specified, or address is 0.0.0.0, send to ip_output(); 200 * otherwise, send to ip_input() and mark as having been received on 201 * the interface with that address. 202 * 203 * If no address specified, or dest port is 0, allow packet to divert 204 * back to this socket; otherwise, don't. 205 */ 206 static int 207 div_output(so, m, addr, control) 208 struct socket *so; 209 register struct mbuf *m; 210 struct mbuf *addr, *control; 211 { 212 register struct inpcb *const inp = sotoinpcb(so); 213 register struct ip *const ip = mtod(m, struct ip *); 214 struct sockaddr_in *sin = NULL; 215 int error = 0; 216 217 if (control) 218 m_freem(control); /* XXX */ 219 if (addr) 220 sin = mtod(addr, struct sockaddr_in *); 221 222 /* Loopback avoidance option */ 223 ip_divert_ignore = ntohs(inp->inp_lport); 224 225 /* Reinject packet into the system as incoming or outgoing */ 226 if (!sin || sin->sin_addr.s_addr == 0) { 227 /* Don't allow both user specified and setsockopt options, 228 and don't allow packet length sizes that will crash */ 229 if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) || 230 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { 231 error = EINVAL; 232 goto cantsend; 233 } 234 235 /* Convert fields to host order for ip_output() */ 236 NTOHS(ip->ip_len); 237 NTOHS(ip->ip_off); 238 239 /* Send packet to output processing */ 240 ipstat.ips_rawout++; /* XXX */ 241 error = ip_output(m, inp->inp_options, &inp->inp_route, 242 (so->so_options & SO_DONTROUTE) | 243 IP_ALLOWBROADCAST | IP_RAWOUTPUT, inp->inp_moptions); 244 } else { 245 struct ifaddr *ifa; 246 247 /* Find receive interface with the given IP address */ 248 sin->sin_port = 0; 249 if ((ifa = ifa_ifwithaddr((struct sockaddr *) sin)) == 0) { 250 error = EADDRNOTAVAIL; 251 goto cantsend; 252 } 253 m->m_pkthdr.rcvif = ifa->ifa_ifp; 254 255 /* Send packet to input processing */ 256 ip_input(m); 257 } 258 259 /* Reset for next time (and other packets) */ 260 ip_divert_ignore = 0; 261 return error; 262 263 cantsend: 264 ip_divert_ignore = 0; 265 m_freem(m); 266 return error; 267 } 268 269 static int 270 div_attach(struct socket *so, int proto, struct proc *p) 271 { 272 struct inpcb *inp; 273 int error; 274 275 inp = sotoinpcb(so); 276 if (inp) 277 panic("div_attach"); 278 if (p && (error = suser(p->p_ucred, &p->p_acflag)) != 0) 279 return error; 280 281 if ((error = soreserve(so, div_sendspace, div_recvspace)) || 282 (error = in_pcballoc(so, &divcbinfo, p))) 283 return error; 284 inp = (struct inpcb *)so->so_pcb; 285 inp->inp_ip_p = proto; 286 inp->inp_flags |= INP_HDRINCL; 287 /* The socket is always "connected" because 288 we always know "where" to send the packet */ 289 so->so_state |= SS_ISCONNECTED; 290 return 0; 291 } 292 293 static int 294 div_detach(struct socket *so) 295 { 296 struct inpcb *inp; 297 298 inp = sotoinpcb(so); 299 if (inp == 0) 300 panic("div_detach"); 301 in_pcbdetach(inp); 302 return 0; 303 } 304 305 static int 306 div_abort(struct socket *so) 307 { 308 soisdisconnected(so); 309 return div_detach(so); 310 } 311 312 static int 313 div_disconnect(struct socket *so) 314 { 315 if ((so->so_state & SS_ISCONNECTED) == 0) 316 return ENOTCONN; 317 return div_abort(so); 318 } 319 320 static int 321 div_bind(struct socket *so, struct mbuf *nam, struct proc *p) 322 { 323 struct inpcb *inp; 324 int s; 325 int error; 326 327 s = splnet(); 328 inp = sotoinpcb(so); 329 error = in_pcbbind(inp, nam, p); 330 splx(s); 331 return 0; 332 } 333 334 static int 335 div_shutdown(struct socket *so) 336 { 337 socantsendmore(so); 338 return 0; 339 } 340 341 static int 342 div_send(struct socket *so, int flags, struct mbuf *m, struct mbuf *nam, 343 struct mbuf *control, struct proc *p) 344 { 345 /* Packet must have a header (but that's about it) */ 346 if (m->m_len < sizeof (struct ip) || 347 (m = m_pullup(m, sizeof (struct ip))) == 0) { 348 ipstat.ips_toosmall++; 349 m_freem(m); 350 return EINVAL; 351 } 352 353 /* Send packet */ 354 return div_output(so, m, nam, control); 355 } 356 357 struct pr_usrreqs div_usrreqs = { 358 div_abort, pru_accept_notsupp, div_attach, div_bind, 359 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, 360 div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp, 361 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, 362 in_setsockaddr, sosend, soreceive, soselect 363 }; 364 365