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 | IFCAP_RSS; 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 if ((ifp->if_capenable & IFCAP_RSS) == 0) 160 m->m_flags &= ~M_HASH; 161 return (if_simloop(ifp, m, dst->sa_family, 0)); 162 } 163 164 /* 165 * if_simloop() 166 * 167 * This function is to support software emulation of hardware loopback, 168 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't 169 * hear their own broadcasts, we create a copy of the packet that we 170 * would normally receive via a hardware loopback. 171 * 172 * This function expects the packet to include the media header of length hlen. 173 */ 174 int 175 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen) 176 { 177 int isr; 178 179 KASSERT((m->m_flags & M_PKTHDR) != 0, ("if_simloop: no HDR")); 180 m->m_pkthdr.rcvif = ifp; 181 182 /* BPF write needs to be handled specially */ 183 if (af == AF_UNSPEC) { 184 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len")); 185 af = *(mtod(m, int *)); 186 m->m_len -= sizeof(int); 187 m->m_pkthdr.len -= sizeof(int); 188 m->m_data += sizeof(int); 189 } 190 191 if (ifp->if_bpf) { 192 bpf_gettoken(); 193 194 /* Re-check */ 195 if (ifp->if_bpf == NULL) 196 goto rel; 197 198 if (ifp->if_bpf->bif_dlt == DLT_NULL) { 199 uint32_t bpf_af = (uint32_t)af; 200 bpf_ptap(ifp->if_bpf, m, &bpf_af, 4); 201 } else { 202 bpf_mtap(ifp->if_bpf, m); 203 } 204 rel: 205 bpf_reltoken(); 206 } 207 208 /* Strip away media header */ 209 if (hlen > 0) 210 m_adj(m, hlen); 211 212 #ifdef ALTQ 213 /* 214 * altq for loop is just for debugging. 215 * only used when called for loop interface (not for 216 * a simplex interface). 217 */ 218 if (ifq_is_enabled(&ifp->if_snd) && ifp->if_start == lo_altqstart) { 219 struct altq_pktattr pktattr; 220 int32_t *afp; 221 222 /* 223 * if the queueing discipline needs packet classification, 224 * do it before prepending link headers. 225 */ 226 ifq_classify(&ifp->if_snd, m, af, &pktattr); 227 228 M_PREPEND(m, sizeof(int32_t), M_NOWAIT); 229 if (m == NULL) 230 return(ENOBUFS); 231 afp = mtod(m, int32_t *); 232 *afp = (int32_t)af; 233 234 return ifq_dispatch(ifp, m, &pktattr); 235 } 236 #endif /* ALTQ */ 237 238 /* Deliver to upper layer protocol */ 239 switch (af) { 240 #ifdef INET 241 case AF_INET: 242 isr = NETISR_IP; 243 break; 244 #endif 245 #ifdef INET6 246 case AF_INET6: 247 m->m_flags |= M_LOOP; 248 isr = NETISR_IPV6; 249 break; 250 #endif 251 default: 252 kprintf("if_simloop: can't handle af=%d\n", af); 253 m_freem(m); 254 return (EAFNOSUPPORT); 255 } 256 257 IFNET_STAT_INC(ifp, ipackets, 1); 258 IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len); 259 netisr_queue(isr, m); 260 return (0); 261 } 262 263 #ifdef ALTQ 264 static void 265 lo_altqstart(struct ifnet *ifp, struct ifaltq_subque *ifsq) 266 { 267 struct mbuf *m; 268 int32_t af, *afp; 269 int isr; 270 271 while (1) { 272 crit_enter(); 273 m = ifsq_dequeue(ifsq); 274 crit_exit(); 275 if (m == NULL) 276 return; 277 278 afp = mtod(m, int32_t *); 279 af = *afp; 280 m_adj(m, sizeof(int32_t)); 281 282 switch (af) { 283 #ifdef INET 284 case AF_INET: 285 isr = NETISR_IP; 286 break; 287 #endif 288 #ifdef INET6 289 case AF_INET6: 290 m->m_flags |= M_LOOP; 291 isr = NETISR_IPV6; 292 break; 293 #endif 294 default: 295 kprintf("lo_altqstart: can't handle af%d\n", af); 296 m_freem(m); 297 return; 298 } 299 300 IFNET_STAT_INC(ifp, ipackets, 1); 301 IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len); 302 netisr_queue(isr, m); 303 } 304 } 305 #endif /* ALTQ */ 306 307 /* ARGSUSED */ 308 static void 309 lortrequest(int cmd, struct rtentry *rt) 310 { 311 if (rt) { 312 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */ 313 /* 314 * For optimal performance, the send and receive buffers 315 * should be at least twice the MTU plus a little more for 316 * overhead. 317 */ 318 rt->rt_rmx.rmx_recvpipe = rt->rt_rmx.rmx_sendpipe = 3 * LOMTU; 319 } 320 } 321 322 /* 323 * Process an ioctl request. 324 */ 325 /* ARGSUSED */ 326 static int 327 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 328 { 329 struct ifaddr *ifa; 330 struct ifreq *ifr = (struct ifreq *)data; 331 int error = 0, mask; 332 333 switch (cmd) { 334 case SIOCSIFADDR: 335 ifp->if_flags |= IFF_UP | IFF_RUNNING; 336 ifa = (struct ifaddr *)data; 337 ifa->ifa_rtrequest = lortrequest; 338 /* 339 * Everything else is done at a higher level. 340 */ 341 break; 342 343 case SIOCADDMULTI: 344 case SIOCDELMULTI: 345 if (ifr == NULL) { 346 error = EAFNOSUPPORT; /* XXX */ 347 break; 348 } 349 switch (ifr->ifr_addr.sa_family) { 350 351 #ifdef INET 352 case AF_INET: 353 break; 354 #endif 355 #ifdef INET6 356 case AF_INET6: 357 break; 358 #endif 359 360 default: 361 error = EAFNOSUPPORT; 362 break; 363 } 364 break; 365 366 case SIOCSIFMTU: 367 ifp->if_mtu = ifr->ifr_mtu; 368 break; 369 370 case SIOCSIFFLAGS: 371 break; 372 373 case SIOCSIFCAP: 374 mask = ifr->ifr_reqcap ^ ifp->if_capenable; 375 if (mask & IFCAP_HWCSUM) { 376 ifp->if_capenable ^= (mask & IFCAP_HWCSUM); 377 if (IFCAP_TXCSUM & ifp->if_capenable) 378 ifp->if_hwassist = LO_CSUM_FEATURES; 379 else 380 ifp->if_hwassist = 0; 381 } 382 if (mask & IFCAP_RSS) 383 ifp->if_capenable ^= IFCAP_RSS; 384 break; 385 386 default: 387 error = EINVAL; 388 } 389 return (error); 390 } 391