1 /*- 2 * SPDX-License-Identifier: ISC 3 * 4 * The authors of this code are John Ioannidis (ji@tla.org), 5 * Angelos D. Keromytis (kermit@csd.uch.gr) and 6 * Niels Provos (provos@physnet.uni-hamburg.de). 7 * 8 * This code was written by John Ioannidis for BSD/OS in Athens, Greece, 9 * in November 1995. 10 * 11 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 12 * by Angelos D. Keromytis. 13 * 14 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 15 * and Niels Provos. 16 * 17 * Copyright (C) 1995, 1996, 1997, 1998 by John Ioannidis, Angelos D. Keromytis 18 * and Niels Provos. 19 * Copyright (c) 2001, Angelos D. Keromytis, Niels Provos. 20 * 21 * Permission to use, copy, and modify this software with or without fee 22 * is hereby granted, provided that this entire notice is included in 23 * all copies of any software which is or includes a copy or 24 * modification of this software. 25 * You may use this code under the GNU public license if you so wish. Please 26 * contribute changes back to the authors under this freer than GPL license 27 * so that we may further the use of strong encryption without limitations to 28 * all. 29 * 30 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 31 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 32 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 33 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 34 * PURPOSE. 35 * 36 * $OpenBSD: if_pflog.c,v 1.26 2007/10/18 21:58:18 mpf Exp $ 37 */ 38 39 #include <sys/cdefs.h> 40 #include "opt_inet.h" 41 #include "opt_inet6.h" 42 #include "opt_bpf.h" 43 #include "opt_pf.h" 44 45 #include <sys/param.h> 46 #include <sys/kernel.h> 47 #include <sys/mbuf.h> 48 #include <sys/module.h> 49 #include <sys/proc.h> 50 #include <sys/socket.h> 51 #include <sys/sockio.h> 52 53 #include <net/bpf.h> 54 #include <net/if.h> 55 #include <net/if_var.h> 56 #include <net/if_clone.h> 57 #include <net/if_pflog.h> 58 #include <net/if_private.h> 59 #include <net/if_types.h> 60 #include <net/vnet.h> 61 #include <net/pfvar.h> 62 63 #if defined(INET) || defined(INET6) 64 #include <netinet/in.h> 65 #endif 66 #ifdef INET 67 #include <netinet/in_var.h> 68 #include <netinet/ip.h> 69 #endif 70 71 #ifdef INET6 72 #include <netinet6/in6_var.h> 73 #include <netinet6/nd6.h> 74 #endif /* INET6 */ 75 76 #ifdef INET 77 #include <machine/in_cksum.h> 78 #endif /* INET */ 79 80 #define PFLOGMTU (32768 + MHLEN + MLEN) 81 82 #ifdef PFLOGDEBUG 83 #define DPRINTF(x) do { if (pflogdebug) printf x ; } while (0) 84 #else 85 #define DPRINTF(x) 86 #endif 87 88 static int pflogoutput(struct ifnet *, struct mbuf *, 89 const struct sockaddr *, struct route *); 90 static void pflogattach(int); 91 static int pflogifs_resize(size_t); 92 static int pflogioctl(struct ifnet *, u_long, caddr_t); 93 static void pflogstart(struct ifnet *); 94 static int pflog_clone_create(struct if_clone *, char *, size_t, 95 struct ifc_data *, struct ifnet **); 96 static int pflog_clone_destroy(struct if_clone *, struct ifnet *, uint32_t); 97 98 static const char pflogname[] = "pflog"; 99 100 VNET_DEFINE_STATIC(struct if_clone *, pflog_cloner); 101 #define V_pflog_cloner VNET(pflog_cloner) 102 103 VNET_DEFINE_STATIC(int, npflogifs) = 0; 104 #define V_npflogifs VNET(npflogifs) 105 VNET_DEFINE(struct ifnet **, pflogifs); /* for fast access */ 106 #define V_pflogifs VNET(pflogifs) 107 108 static void 109 pflogattach(int npflog __unused) 110 { 111 struct if_clone_addreq req = { 112 .create_f = pflog_clone_create, 113 .destroy_f = pflog_clone_destroy, 114 .flags = IFC_F_AUTOUNIT, 115 }; 116 V_pflog_cloner = ifc_attach_cloner(pflogname, &req); 117 struct ifc_data ifd = { .unit = 0 }; 118 ifc_create_ifp(pflogname, &ifd, NULL); 119 } 120 121 static int 122 pflogifs_resize(size_t n) 123 { 124 struct ifnet **p; 125 int i; 126 127 if (n > SIZE_MAX / sizeof(struct ifnet *)) 128 return (EINVAL); 129 if (n == 0) 130 p = NULL; 131 else if ((p = malloc(n * sizeof(struct ifnet *), M_DEVBUF, 132 M_NOWAIT | M_ZERO)) == NULL) 133 return (ENOMEM); 134 for (i = 0; i < n; i++) { 135 if (i < V_npflogifs) 136 p[i] = V_pflogifs[i]; 137 else 138 p[i] = NULL; 139 } 140 141 if (V_pflogifs) 142 free(V_pflogifs, M_DEVBUF); 143 V_pflogifs = p; 144 V_npflogifs = n; 145 146 return (0); 147 } 148 149 static int 150 pflog_clone_create(struct if_clone *ifc, char *name, size_t maxlen, 151 struct ifc_data *ifd, struct ifnet **ifpp) 152 { 153 struct ifnet *ifp; 154 155 ifp = if_alloc(IFT_PFLOG); 156 if_initname(ifp, pflogname, ifd->unit); 157 ifp->if_mtu = PFLOGMTU; 158 ifp->if_ioctl = pflogioctl; 159 ifp->if_output = pflogoutput; 160 ifp->if_start = pflogstart; 161 ifp->if_snd.ifq_maxlen = ifqmaxlen; 162 ifp->if_hdrlen = PFLOG_HDRLEN; 163 if_attach(ifp); 164 165 bpfattach(ifp, DLT_PFLOG, PFLOG_HDRLEN); 166 167 if (ifd->unit + 1 > V_npflogifs && 168 pflogifs_resize(ifd->unit + 1) != 0) { 169 pflog_clone_destroy(ifc, ifp, IFC_F_FORCE); 170 return (ENOMEM); 171 } 172 V_pflogifs[ifd->unit] = ifp; 173 *ifpp = ifp; 174 175 return (0); 176 } 177 178 static int 179 pflog_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags) 180 { 181 int i; 182 183 if (ifp->if_dunit == 0 && (flags & IFC_F_FORCE) == 0) 184 return (EINVAL); 185 186 for (i = 0; i < V_npflogifs; i++) 187 if (V_pflogifs[i] == ifp) 188 V_pflogifs[i] = NULL; 189 190 bpfdetach(ifp); 191 if_detach(ifp); 192 if_free(ifp); 193 194 return (0); 195 } 196 197 /* 198 * Start output on the pflog interface. 199 */ 200 static void 201 pflogstart(struct ifnet *ifp) 202 { 203 struct mbuf *m; 204 205 for (;;) { 206 IF_LOCK(&ifp->if_snd); 207 _IF_DEQUEUE(&ifp->if_snd, m); 208 IF_UNLOCK(&ifp->if_snd); 209 210 if (m == NULL) 211 return; 212 else 213 m_freem(m); 214 } 215 } 216 217 static int 218 pflogoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst, 219 struct route *rt) 220 { 221 m_freem(m); 222 return (0); 223 } 224 225 /* ARGSUSED */ 226 static int 227 pflogioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 228 { 229 switch (cmd) { 230 case SIOCSIFFLAGS: 231 if (ifp->if_flags & IFF_UP) 232 ifp->if_drv_flags |= IFF_DRV_RUNNING; 233 else 234 ifp->if_drv_flags &= ~IFF_DRV_RUNNING; 235 break; 236 default: 237 return (ENOTTY); 238 } 239 240 return (0); 241 } 242 243 static int 244 pflog_packet(uint8_t action, u_int8_t reason, 245 struct pf_krule *rm, struct pf_krule *am, 246 struct pf_kruleset *ruleset, struct pf_pdesc *pd, int lookupsafe, 247 struct pf_krule *trigger) 248 { 249 struct ifnet *ifn; 250 struct pfloghdr hdr; 251 252 if (rm == NULL || pd == NULL) 253 return (1); 254 if (trigger == NULL) 255 trigger = rm; 256 257 if (trigger->logif > V_npflogifs) 258 return (0); 259 260 ifn = V_pflogifs[trigger->logif]; 261 if (ifn == NULL || !bpf_peers_present(ifn->if_bpf)) 262 return (0); 263 264 bzero(&hdr, sizeof(hdr)); 265 hdr.length = PFLOG_REAL_HDRLEN; 266 hdr.af = pd->af; 267 hdr.action = action; 268 hdr.reason = reason; 269 memcpy(hdr.ifname, pd->kif->pfik_name, sizeof(hdr.ifname)); 270 271 if (am == NULL) { 272 hdr.rulenr = htonl(rm->nr); 273 hdr.subrulenr = -1; 274 } else { 275 hdr.rulenr = htonl(am->nr); 276 hdr.subrulenr = htonl(rm->nr); 277 if (ruleset != NULL && ruleset->anchor != NULL) 278 strlcpy(hdr.ruleset, ruleset->anchor->name, 279 sizeof(hdr.ruleset)); 280 } 281 hdr.ridentifier = htonl(rm->ridentifier); 282 /* 283 * XXXGL: we avoid pf_socket_lookup() when we are holding 284 * state lock, since this leads to unsafe LOR. 285 * These conditions are very very rare, however. 286 */ 287 if (trigger->log & PF_LOG_SOCKET_LOOKUP && !pd->lookup.done && lookupsafe) 288 pd->lookup.done = pf_socket_lookup(pd); 289 if (pd->lookup.done > 0) 290 hdr.uid = pd->lookup.uid; 291 else 292 hdr.uid = UID_MAX; 293 hdr.pid = NO_PID; 294 hdr.rule_uid = rm->cuid; 295 hdr.rule_pid = rm->cpid; 296 hdr.dir = pd->dir; 297 298 #ifdef INET 299 if (pd->af == AF_INET && pd->dir == PF_OUT) { 300 struct ip *ip; 301 302 ip = mtod(pd->m, struct ip *); 303 ip->ip_sum = 0; 304 ip->ip_sum = in_cksum(pd->m, ip->ip_hl << 2); 305 } 306 #endif /* INET */ 307 308 if_inc_counter(ifn, IFCOUNTER_OPACKETS, 1); 309 if_inc_counter(ifn, IFCOUNTER_OBYTES, pd->m->m_pkthdr.len); 310 bpf_mtap2(ifn->if_bpf, &hdr, PFLOG_HDRLEN, pd->m); 311 312 return (0); 313 } 314 315 static void 316 vnet_pflog_init(const void *unused __unused) 317 { 318 319 pflogattach(1); 320 } 321 VNET_SYSINIT(vnet_pflog_init, SI_SUB_PROTO_FIREWALL, SI_ORDER_ANY, 322 vnet_pflog_init, NULL); 323 324 static void 325 vnet_pflog_uninit(const void *unused __unused) 326 { 327 328 ifc_detach_cloner(V_pflog_cloner); 329 } 330 /* 331 * Detach after pf is gone; otherwise we might touch pflog memory 332 * from within pf after freeing pflog. 333 */ 334 VNET_SYSUNINIT(vnet_pflog_uninit, SI_SUB_INIT_IF, SI_ORDER_SECOND, 335 vnet_pflog_uninit, NULL); 336 337 static int 338 pflog_modevent(module_t mod, int type, void *data) 339 { 340 int error = 0; 341 342 switch (type) { 343 case MOD_LOAD: 344 PF_RULES_WLOCK(); 345 pflog_packet_ptr = pflog_packet; 346 PF_RULES_WUNLOCK(); 347 break; 348 case MOD_UNLOAD: 349 PF_RULES_WLOCK(); 350 pflog_packet_ptr = NULL; 351 PF_RULES_WUNLOCK(); 352 break; 353 default: 354 error = EOPNOTSUPP; 355 break; 356 } 357 358 return error; 359 } 360 361 static moduledata_t pflog_mod = { pflogname, pflog_modevent, 0 }; 362 363 #define PFLOG_MODVER 1 364 365 /* Do not run before pf is initialized as we depend on its locks. */ 366 DECLARE_MODULE(pflog, pflog_mod, SI_SUB_PROTO_FIREWALL, SI_ORDER_ANY); 367 MODULE_VERSION(pflog, PFLOG_MODVER); 368 MODULE_DEPEND(pflog, pf, PF_MODVER, PF_MODVER, PF_MODVER); 369