1 /* 2 * Copyright (c) 1982, 1986, 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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)if_loop.c 8.1 (Berkeley) 6/10/93 30 * $FreeBSD: src/sys/net/if_loop.c,v 1.47.2.9 2004/02/08 08:40:24 silby Exp $ 31 */ 32 33 /* 34 * Loopback interface driver for protocol testing and timing. 35 */ 36 #include "use_loop.h" 37 38 #include "opt_inet.h" 39 #include "opt_inet6.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/kernel.h> 44 #include <sys/lock.h> 45 #include <sys/mbuf.h> 46 #include <sys/socket.h> 47 #include <sys/sockio.h> 48 49 #include <sys/mplock2.h> 50 51 #include <net/if.h> 52 #include <net/if_types.h> 53 #include <net/ifq_var.h> 54 #include <net/netisr.h> 55 #include <net/route.h> 56 #include <net/bpf.h> 57 #include <net/bpfdesc.h> 58 59 #ifdef INET 60 #include <netinet/in.h> 61 #include <netinet/in_var.h> 62 #endif 63 64 #ifdef INET6 65 #ifndef INET 66 #include <netinet/in.h> 67 #endif 68 #include <netinet6/in6_var.h> 69 #include <netinet/ip6.h> 70 #endif 71 72 static void loopattach(void *); 73 static int looutput(struct ifnet *, struct mbuf *, struct sockaddr *, 74 struct rtentry *); 75 static int loioctl(struct ifnet *, u_long, caddr_t, struct ucred *); 76 static void lortrequest(int, struct rtentry *); 77 #ifdef ALTQ 78 static void lo_altqstart(struct ifnet *, struct ifaltq_subque *); 79 #endif 80 PSEUDO_SET(loopattach, if_loop); 81 82 #ifdef TINY_LOMTU 83 #define LOMTU (1024+512) 84 #elif defined(LARGE_LOMTU) 85 #define LOMTU 131072 86 #else 87 #define LOMTU 16384 88 #endif 89 90 #define LO_CSUM_FEATURES (CSUM_IP | CSUM_UDP | CSUM_TCP) 91 92 struct ifnet loif[NLOOP]; 93 94 /* ARGSUSED */ 95 static void 96 loopattach(void *dummy) 97 { 98 struct ifnet *ifp; 99 int i; 100 101 for (i = 0, ifp = loif; i < NLOOP; i++, ifp++) { 102 if_initname(ifp, "lo", i); 103 ifp->if_mtu = LOMTU; 104 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST; 105 ifp->if_capabilities = IFCAP_HWCSUM; 106 ifp->if_hwassist = LO_CSUM_FEATURES; 107 ifp->if_capenable = ifp->if_capabilities; 108 ifp->if_ioctl = loioctl; 109 ifp->if_output = looutput; 110 ifp->if_type = IFT_LOOP; 111 ifq_set_maxlen(&ifp->if_snd, ifqmaxlen); 112 ifq_set_ready(&ifp->if_snd); 113 #ifdef ALTQ 114 ifp->if_start = lo_altqstart; 115 #endif 116 if_attach(ifp, NULL); 117 bpfattach(ifp, DLT_NULL, sizeof(u_int)); 118 } 119 } 120 121 static int 122 looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 123 struct rtentry *rt) 124 { 125 M_ASSERTPKTHDR(m); 126 127 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) { 128 m_freem(m); 129 return (rt->rt_flags & RTF_BLACKHOLE ? 0 : 130 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH); 131 } 132 133 IFNET_STAT_INC(ifp, opackets, 1); 134 IFNET_STAT_INC(ifp, obytes, m->m_pkthdr.len); 135 #if 1 /* XXX */ 136 switch (dst->sa_family) { 137 case AF_INET: 138 case AF_INET6: 139 break; 140 default: 141 kprintf("looutput: af=%d unexpected\n", dst->sa_family); 142 m_freem(m); 143 return (EAFNOSUPPORT); 144 } 145 #endif 146 147 if (ifp->if_capenable & IFCAP_RXCSUM) { 148 int csum_flags = 0; 149 150 if (m->m_pkthdr.csum_flags & CSUM_IP) 151 csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID); 152 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) 153 csum_flags |= (CSUM_DATA_VALID | CSUM_PSEUDO_HDR); 154 155 m->m_pkthdr.csum_flags |= csum_flags; 156 if (csum_flags & CSUM_DATA_VALID) 157 m->m_pkthdr.csum_data = 0xffff; 158 } 159 return (if_simloop(ifp, m, dst->sa_family, 0)); 160 } 161 162 /* 163 * if_simloop() 164 * 165 * This function is to support software emulation of hardware loopback, 166 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't 167 * hear their own broadcasts, we create a copy of the packet that we 168 * would normally receive via a hardware loopback. 169 * 170 * This function expects the packet to include the media header of length hlen. 171 */ 172 int 173 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen) 174 { 175 int isr; 176 177 KASSERT((m->m_flags & M_PKTHDR) != 0, ("if_simloop: no HDR")); 178 m->m_pkthdr.rcvif = ifp; 179 180 /* BPF write needs to be handled specially */ 181 if (af == AF_UNSPEC) { 182 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len")); 183 af = *(mtod(m, int *)); 184 m->m_len -= sizeof(int); 185 m->m_pkthdr.len -= sizeof(int); 186 m->m_data += sizeof(int); 187 } 188 189 if (ifp->if_bpf) { 190 bpf_gettoken(); 191 192 /* Re-check */ 193 if (ifp->if_bpf == NULL) 194 goto rel; 195 196 if (ifp->if_bpf->bif_dlt == DLT_NULL) { 197 uint32_t bpf_af = (uint32_t)af; 198 bpf_ptap(ifp->if_bpf, m, &bpf_af, 4); 199 } else { 200 bpf_mtap(ifp->if_bpf, m); 201 } 202 rel: 203 bpf_reltoken(); 204 } 205 206 /* Strip away media header */ 207 if (hlen > 0) 208 m_adj(m, hlen); 209 210 #ifdef ALTQ 211 /* 212 * altq for loop is just for debugging. 213 * only used when called for loop interface (not for 214 * a simplex interface). 215 */ 216 if (ifq_is_enabled(&ifp->if_snd) && ifp->if_start == lo_altqstart) { 217 struct altq_pktattr pktattr; 218 int32_t *afp; 219 220 /* 221 * if the queueing discipline needs packet classification, 222 * do it before prepending link headers. 223 */ 224 ifq_classify(&ifp->if_snd, m, af, &pktattr); 225 226 M_PREPEND(m, sizeof(int32_t), M_NOWAIT); 227 if (m == NULL) 228 return(ENOBUFS); 229 afp = mtod(m, int32_t *); 230 *afp = (int32_t)af; 231 232 return ifq_dispatch(ifp, m, &pktattr); 233 } 234 #endif /* ALTQ */ 235 236 /* Deliver to upper layer protocol */ 237 switch (af) { 238 #ifdef INET 239 case AF_INET: 240 isr = NETISR_IP; 241 break; 242 #endif 243 #ifdef INET6 244 case AF_INET6: 245 m->m_flags |= M_LOOP; 246 isr = NETISR_IPV6; 247 break; 248 #endif 249 default: 250 kprintf("if_simloop: can't handle af=%d\n", af); 251 m_freem(m); 252 return (EAFNOSUPPORT); 253 } 254 255 IFNET_STAT_INC(ifp, ipackets, 1); 256 IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len); 257 netisr_queue(isr, m); 258 return (0); 259 } 260 261 #ifdef ALTQ 262 static void 263 lo_altqstart(struct ifnet *ifp, struct ifaltq_subque *ifsq) 264 { 265 struct mbuf *m; 266 int32_t af, *afp; 267 int isr; 268 269 while (1) { 270 crit_enter(); 271 m = ifsq_dequeue(ifsq); 272 crit_exit(); 273 if (m == NULL) 274 return; 275 276 afp = mtod(m, int32_t *); 277 af = *afp; 278 m_adj(m, sizeof(int32_t)); 279 280 switch (af) { 281 #ifdef INET 282 case AF_INET: 283 isr = NETISR_IP; 284 break; 285 #endif 286 #ifdef INET6 287 case AF_INET6: 288 m->m_flags |= M_LOOP; 289 isr = NETISR_IPV6; 290 break; 291 #endif 292 #ifdef ISO 293 case AF_ISO: 294 isr = NETISR_ISO; 295 break; 296 #endif 297 default: 298 kprintf("lo_altqstart: can't handle af%d\n", af); 299 m_freem(m); 300 return; 301 } 302 303 IFNET_STAT_INC(ifp, ipackets, 1); 304 IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len); 305 netisr_queue(isr, m); 306 } 307 } 308 #endif /* ALTQ */ 309 310 /* ARGSUSED */ 311 static void 312 lortrequest(int cmd, struct rtentry *rt) 313 { 314 if (rt) { 315 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */ 316 /* 317 * For optimal performance, the send and receive buffers 318 * should be at least twice the MTU plus a little more for 319 * overhead. 320 */ 321 rt->rt_rmx.rmx_recvpipe = rt->rt_rmx.rmx_sendpipe = 3 * LOMTU; 322 } 323 } 324 325 /* 326 * Process an ioctl request. 327 */ 328 /* ARGSUSED */ 329 static int 330 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 331 { 332 struct ifaddr *ifa; 333 struct ifreq *ifr = (struct ifreq *)data; 334 int error = 0, mask; 335 336 switch (cmd) { 337 case SIOCSIFADDR: 338 ifp->if_flags |= IFF_UP | IFF_RUNNING; 339 ifa = (struct ifaddr *)data; 340 ifa->ifa_rtrequest = lortrequest; 341 /* 342 * Everything else is done at a higher level. 343 */ 344 break; 345 346 case SIOCADDMULTI: 347 case SIOCDELMULTI: 348 if (ifr == NULL) { 349 error = EAFNOSUPPORT; /* XXX */ 350 break; 351 } 352 switch (ifr->ifr_addr.sa_family) { 353 354 #ifdef INET 355 case AF_INET: 356 break; 357 #endif 358 #ifdef INET6 359 case AF_INET6: 360 break; 361 #endif 362 363 default: 364 error = EAFNOSUPPORT; 365 break; 366 } 367 break; 368 369 case SIOCSIFMTU: 370 ifp->if_mtu = ifr->ifr_mtu; 371 break; 372 373 case SIOCSIFFLAGS: 374 break; 375 376 case SIOCSIFCAP: 377 mask = (ifr->ifr_reqcap ^ ifp->if_capenable) & IFCAP_HWCSUM; 378 if (mask) { 379 ifp->if_capenable ^= mask; 380 if (IFCAP_TXCSUM & ifp->if_capenable) 381 ifp->if_hwassist = LO_CSUM_FEATURES; 382 else 383 ifp->if_hwassist = 0; 384 } 385 break; 386 387 default: 388 error = EINVAL; 389 } 390 return (error); 391 } 392