1152592Sandre/* 2152592Sandre * Copyright (c) 1982, 1986, 1988, 1993 3169464Srwatson * The Regents of the University of California. 4169464Srwatson * Copyright (c) 2005 Andre Oppermann, Internet Business Solutions AG. 5169464Srwatson * All rights reserved. 6152592Sandre * 7152592Sandre * Redistribution and use in source and binary forms, with or without 8152592Sandre * modification, are permitted provided that the following conditions 9152592Sandre * are met: 10152592Sandre * 1. Redistributions of source code must retain the above copyright 11152592Sandre * notice, this list of conditions and the following disclaimer. 12152592Sandre * 2. Redistributions in binary form must reproduce the above copyright 13152592Sandre * notice, this list of conditions and the following disclaimer in the 14152592Sandre * documentation and/or other materials provided with the distribution. 15152592Sandre * 4. Neither the name of the University nor the names of its contributors 16152592Sandre * may be used to endorse or promote products derived from this software 17152592Sandre * without specific prior written permission. 18152592Sandre * 19152592Sandre * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20152592Sandre * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21152592Sandre * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22152592Sandre * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23152592Sandre * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24152592Sandre * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25152592Sandre * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26152592Sandre * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27152592Sandre * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28152592Sandre * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29152592Sandre * SUCH DAMAGE. 30152592Sandre */ 31152592Sandre 32172467Ssilby#include <sys/cdefs.h> 33172467Ssilby__FBSDID("$FreeBSD$"); 34172467Ssilby 35152592Sandre#include "opt_ipstealth.h" 36152592Sandre 37152592Sandre#include <sys/param.h> 38152592Sandre#include <sys/systm.h> 39152592Sandre#include <sys/mbuf.h> 40152592Sandre#include <sys/domain.h> 41152592Sandre#include <sys/protosw.h> 42152592Sandre#include <sys/socket.h> 43152592Sandre#include <sys/time.h> 44152592Sandre#include <sys/kernel.h> 45152592Sandre#include <sys/syslog.h> 46152592Sandre#include <sys/sysctl.h> 47152592Sandre 48152592Sandre#include <net/if.h> 49152592Sandre#include <net/if_types.h> 50152592Sandre#include <net/if_var.h> 51152592Sandre#include <net/if_dl.h> 52152592Sandre#include <net/route.h> 53152592Sandre#include <net/netisr.h> 54196019Srwatson#include <net/vnet.h> 55152592Sandre 56152592Sandre#include <netinet/in.h> 57152592Sandre#include <netinet/in_systm.h> 58152592Sandre#include <netinet/in_var.h> 59152592Sandre#include <netinet/ip.h> 60152592Sandre#include <netinet/in_pcb.h> 61152592Sandre#include <netinet/ip_var.h> 62152592Sandre#include <netinet/ip_options.h> 63152592Sandre#include <netinet/ip_icmp.h> 64152592Sandre#include <machine/in_cksum.h> 65152592Sandre 66152592Sandre#include <sys/socketvar.h> 67152592Sandre 68152592Sandrestatic int ip_dosourceroute = 0; 69152592SandreSYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 70152592Sandre &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 71152592Sandre 72152592Sandrestatic int ip_acceptsourceroute = 0; 73152592SandreSYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 74152592Sandre CTLFLAG_RW, &ip_acceptsourceroute, 0, 75152592Sandre "Enable accepting source routed IP packets"); 76152592Sandre 77152592Sandreint ip_doopts = 1; /* 0 = ignore, 1 = process, 2 = reject */ 78152592SandreSYSCTL_INT(_net_inet_ip, OID_AUTO, process_options, CTLFLAG_RW, 79152592Sandre &ip_doopts, 0, "Enable IP options processing ([LS]SRR, RR, TS)"); 80152592Sandre 81152592Sandrestatic void save_rte(struct mbuf *m, u_char *, struct in_addr); 82152592Sandre 83152592Sandre/* 84169464Srwatson * Do option processing on a datagram, possibly discarding it if bad options 85169464Srwatson * are encountered, or forwarding it if source-routed. 86169464Srwatson * 87169464Srwatson * The pass argument is used when operating in the IPSTEALTH mode to tell 88169464Srwatson * what options to process: [LS]SRR (pass 0) or the others (pass 1). The 89169464Srwatson * reason for as many as two passes is that when doing IPSTEALTH, non-routing 90169464Srwatson * options should be processed only if the packet is for us. 91169464Srwatson * 92169464Srwatson * Returns 1 if packet has been forwarded/freed, 0 if the packet should be 93169464Srwatson * processed further. 94152592Sandre */ 95152592Sandreint 96152592Sandreip_dooptions(struct mbuf *m, int pass) 97152592Sandre{ 98152592Sandre struct ip *ip = mtod(m, struct ip *); 99152592Sandre u_char *cp; 100152592Sandre struct in_ifaddr *ia; 101152592Sandre int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 102152592Sandre struct in_addr *sin, dst; 103188578Sluigi uint32_t ntime; 104152592Sandre struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 105152592Sandre 106169464Srwatson /* Ignore or reject packets with IP options. */ 107152592Sandre if (ip_doopts == 0) 108152592Sandre return 0; 109152592Sandre else if (ip_doopts == 2) { 110152592Sandre type = ICMP_UNREACH; 111152592Sandre code = ICMP_UNREACH_FILTER_PROHIB; 112152592Sandre goto bad; 113152592Sandre } 114152592Sandre 115152592Sandre dst = ip->ip_dst; 116152592Sandre cp = (u_char *)(ip + 1); 117152592Sandre cnt = (ip->ip_hl << 2) - sizeof (struct ip); 118152592Sandre for (; cnt > 0; cnt -= optlen, cp += optlen) { 119152592Sandre opt = cp[IPOPT_OPTVAL]; 120152592Sandre if (opt == IPOPT_EOL) 121152592Sandre break; 122152592Sandre if (opt == IPOPT_NOP) 123152592Sandre optlen = 1; 124152592Sandre else { 125152592Sandre if (cnt < IPOPT_OLEN + sizeof(*cp)) { 126152592Sandre code = &cp[IPOPT_OLEN] - (u_char *)ip; 127152592Sandre goto bad; 128152592Sandre } 129152592Sandre optlen = cp[IPOPT_OLEN]; 130152592Sandre if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 131152592Sandre code = &cp[IPOPT_OLEN] - (u_char *)ip; 132152592Sandre goto bad; 133152592Sandre } 134152592Sandre } 135152592Sandre switch (opt) { 136152592Sandre 137152592Sandre default: 138152592Sandre break; 139152592Sandre 140152592Sandre /* 141169464Srwatson * Source routing with record. Find interface with current 142169464Srwatson * destination address. If none on this machine then drop if 143169464Srwatson * strictly routed, or do nothing if loosely routed. Record 144169464Srwatson * interface address and bring up next address component. If 145169464Srwatson * strictly routed make sure next address is on directly 146169464Srwatson * accessible net. 147152592Sandre */ 148152592Sandre case IPOPT_LSRR: 149152592Sandre case IPOPT_SSRR: 150152592Sandre#ifdef IPSTEALTH 151181803Sbz if (V_ipstealth && pass > 0) 152152592Sandre break; 153152592Sandre#endif 154152592Sandre if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 155152592Sandre code = &cp[IPOPT_OLEN] - (u_char *)ip; 156152592Sandre goto bad; 157152592Sandre } 158152592Sandre if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 159152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 160152592Sandre goto bad; 161152592Sandre } 162152592Sandre ipaddr.sin_addr = ip->ip_dst; 163194760Srwatson if (ifa_ifwithaddr_check((struct sockaddr *)&ipaddr) 164194760Srwatson == 0) { 165152592Sandre if (opt == IPOPT_SSRR) { 166152592Sandre type = ICMP_UNREACH; 167152592Sandre code = ICMP_UNREACH_SRCFAIL; 168152592Sandre goto bad; 169152592Sandre } 170152592Sandre if (!ip_dosourceroute) 171152592Sandre goto nosourcerouting; 172152592Sandre /* 173152592Sandre * Loose routing, and not at next destination 174152592Sandre * yet; nothing to do except forward. 175152592Sandre */ 176152592Sandre break; 177152592Sandre } 178152592Sandre off--; /* 0 origin */ 179152592Sandre if (off > optlen - (int)sizeof(struct in_addr)) { 180152592Sandre /* 181152592Sandre * End of source route. Should be for us. 182152592Sandre */ 183152592Sandre if (!ip_acceptsourceroute) 184152592Sandre goto nosourcerouting; 185152592Sandre save_rte(m, cp, ip->ip_src); 186152592Sandre break; 187152592Sandre } 188152592Sandre#ifdef IPSTEALTH 189181803Sbz if (V_ipstealth) 190152592Sandre goto dropit; 191152592Sandre#endif 192152592Sandre if (!ip_dosourceroute) { 193181803Sbz if (V_ipforwarding) { 194152592Sandre char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 195152592Sandre /* 196169464Srwatson * Acting as a router, so generate 197169464Srwatson * ICMP 198152592Sandre */ 199152592Sandrenosourcerouting: 200152592Sandre strcpy(buf, inet_ntoa(ip->ip_dst)); 201152592Sandre log(LOG_WARNING, 202152592Sandre "attempted source route from %s to %s\n", 203152592Sandre inet_ntoa(ip->ip_src), buf); 204152592Sandre type = ICMP_UNREACH; 205152592Sandre code = ICMP_UNREACH_SRCFAIL; 206152592Sandre goto bad; 207152592Sandre } else { 208152592Sandre /* 209169464Srwatson * Not acting as a router, so 210169464Srwatson * silently drop. 211152592Sandre */ 212152592Sandre#ifdef IPSTEALTH 213152592Sandredropit: 214152592Sandre#endif 215190951Srwatson IPSTAT_INC(ips_cantforward); 216152592Sandre m_freem(m); 217152592Sandre return (1); 218152592Sandre } 219152592Sandre } 220152592Sandre 221152592Sandre /* 222152592Sandre * locate outgoing interface 223152592Sandre */ 224152592Sandre (void)memcpy(&ipaddr.sin_addr, cp + off, 225152592Sandre sizeof(ipaddr.sin_addr)); 226152592Sandre 227152592Sandre if (opt == IPOPT_SSRR) { 228152592Sandre#define INA struct in_ifaddr * 229152592Sandre#define SA struct sockaddr * 230152592Sandre if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == NULL) 231208553Sqingli ia = (INA)ifa_ifwithnet((SA)&ipaddr, 0); 232152592Sandre } else 233178888Sjulian/* XXX MRT 0 for routing */ 234178888Sjulian ia = ip_rtaddr(ipaddr.sin_addr, M_GETFIB(m)); 235152592Sandre if (ia == NULL) { 236152592Sandre type = ICMP_UNREACH; 237152592Sandre code = ICMP_UNREACH_SRCFAIL; 238152592Sandre goto bad; 239152592Sandre } 240152592Sandre ip->ip_dst = ipaddr.sin_addr; 241152592Sandre (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 242152592Sandre sizeof(struct in_addr)); 243194760Srwatson ifa_free(&ia->ia_ifa); 244152592Sandre cp[IPOPT_OFFSET] += sizeof(struct in_addr); 245152592Sandre /* 246152592Sandre * Let ip_intr's mcast routing check handle mcast pkts 247152592Sandre */ 248152592Sandre forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 249152592Sandre break; 250152592Sandre 251152592Sandre case IPOPT_RR: 252152592Sandre#ifdef IPSTEALTH 253181803Sbz if (V_ipstealth && pass == 0) 254152592Sandre break; 255152592Sandre#endif 256152592Sandre if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 257152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 258152592Sandre goto bad; 259152592Sandre } 260152592Sandre if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 261152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 262152592Sandre goto bad; 263152592Sandre } 264152592Sandre /* 265152592Sandre * If no space remains, ignore. 266152592Sandre */ 267152592Sandre off--; /* 0 origin */ 268152592Sandre if (off > optlen - (int)sizeof(struct in_addr)) 269152592Sandre break; 270152592Sandre (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 271152592Sandre sizeof(ipaddr.sin_addr)); 272152592Sandre /* 273169464Srwatson * Locate outgoing interface; if we're the 274169464Srwatson * destination, use the incoming interface (should be 275169464Srwatson * same). 276152592Sandre */ 277152592Sandre if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 278178888Sjulian (ia = ip_rtaddr(ipaddr.sin_addr, M_GETFIB(m))) == NULL) { 279152592Sandre type = ICMP_UNREACH; 280152592Sandre code = ICMP_UNREACH_HOST; 281152592Sandre goto bad; 282152592Sandre } 283152592Sandre (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 284152592Sandre sizeof(struct in_addr)); 285194760Srwatson ifa_free(&ia->ia_ifa); 286152592Sandre cp[IPOPT_OFFSET] += sizeof(struct in_addr); 287152592Sandre break; 288152592Sandre 289152592Sandre case IPOPT_TS: 290152592Sandre#ifdef IPSTEALTH 291181803Sbz if (V_ipstealth && pass == 0) 292152592Sandre break; 293152592Sandre#endif 294152592Sandre code = cp - (u_char *)ip; 295152592Sandre if (optlen < 4 || optlen > 40) { 296152592Sandre code = &cp[IPOPT_OLEN] - (u_char *)ip; 297152592Sandre goto bad; 298152592Sandre } 299152592Sandre if ((off = cp[IPOPT_OFFSET]) < 5) { 300152592Sandre code = &cp[IPOPT_OLEN] - (u_char *)ip; 301152592Sandre goto bad; 302152592Sandre } 303152592Sandre if (off > optlen - (int)sizeof(int32_t)) { 304152592Sandre cp[IPOPT_OFFSET + 1] += (1 << 4); 305152592Sandre if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 306152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 307152592Sandre goto bad; 308152592Sandre } 309152592Sandre break; 310152592Sandre } 311152592Sandre off--; /* 0 origin */ 312152592Sandre sin = (struct in_addr *)(cp + off); 313152592Sandre switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 314152592Sandre 315152592Sandre case IPOPT_TS_TSONLY: 316152592Sandre break; 317152592Sandre 318152592Sandre case IPOPT_TS_TSANDADDR: 319188578Sluigi if (off + sizeof(uint32_t) + 320152592Sandre sizeof(struct in_addr) > optlen) { 321152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 322152592Sandre goto bad; 323152592Sandre } 324152592Sandre ipaddr.sin_addr = dst; 325152592Sandre ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 326152592Sandre m->m_pkthdr.rcvif); 327152592Sandre if (ia == NULL) 328152592Sandre continue; 329152592Sandre (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 330152592Sandre sizeof(struct in_addr)); 331194760Srwatson ifa_free(&ia->ia_ifa); 332152592Sandre cp[IPOPT_OFFSET] += sizeof(struct in_addr); 333152592Sandre off += sizeof(struct in_addr); 334152592Sandre break; 335152592Sandre 336152592Sandre case IPOPT_TS_PRESPEC: 337188578Sluigi if (off + sizeof(uint32_t) + 338152592Sandre sizeof(struct in_addr) > optlen) { 339152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 340152592Sandre goto bad; 341152592Sandre } 342152592Sandre (void)memcpy(&ipaddr.sin_addr, sin, 343152592Sandre sizeof(struct in_addr)); 344213832Sbz if (ifa_ifwithaddr_check((SA)&ipaddr) == 0) 345152592Sandre continue; 346152592Sandre cp[IPOPT_OFFSET] += sizeof(struct in_addr); 347152592Sandre off += sizeof(struct in_addr); 348152592Sandre break; 349152592Sandre 350152592Sandre default: 351152592Sandre code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 352152592Sandre goto bad; 353152592Sandre } 354152592Sandre ntime = iptime(); 355188578Sluigi (void)memcpy(cp + off, &ntime, sizeof(uint32_t)); 356188578Sluigi cp[IPOPT_OFFSET] += sizeof(uint32_t); 357152592Sandre } 358152592Sandre } 359181803Sbz if (forward && V_ipforwarding) { 360152592Sandre ip_forward(m, 1); 361152592Sandre return (1); 362152592Sandre } 363152592Sandre return (0); 364152592Sandrebad: 365152592Sandre icmp_error(m, type, code, 0, 0); 366190951Srwatson IPSTAT_INC(ips_badoptions); 367152592Sandre return (1); 368152592Sandre} 369152592Sandre 370152592Sandre/* 371169464Srwatson * Save incoming source route for use in replies, to be picked up later by 372169464Srwatson * ip_srcroute if the receiver is interested. 373152592Sandre */ 374152592Sandrestatic void 375169454Srwatsonsave_rte(struct mbuf *m, u_char *option, struct in_addr dst) 376152592Sandre{ 377152592Sandre unsigned olen; 378152592Sandre struct ipopt_tag *opts; 379152592Sandre 380152592Sandre opts = (struct ipopt_tag *)m_tag_get(PACKET_TAG_IPOPTIONS, 381169464Srwatson sizeof(struct ipopt_tag), M_NOWAIT); 382152592Sandre if (opts == NULL) 383152592Sandre return; 384152592Sandre 385152592Sandre olen = option[IPOPT_OLEN]; 386152592Sandre if (olen > sizeof(opts->ip_srcrt) - (1 + sizeof(dst))) { 387152592Sandre m_tag_free((struct m_tag *)opts); 388152592Sandre return; 389152592Sandre } 390152592Sandre bcopy(option, opts->ip_srcrt.srcopt, olen); 391152592Sandre opts->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 392152592Sandre opts->ip_srcrt.dst = dst; 393152592Sandre m_tag_prepend(m, (struct m_tag *)opts); 394152592Sandre} 395152592Sandre 396152592Sandre/* 397169464Srwatson * Retrieve incoming source route for use in replies, in the same form used 398169464Srwatson * by setsockopt. The first hop is placed before the options, will be 399169464Srwatson * removed later. 400152592Sandre */ 401152592Sandrestruct mbuf * 402169454Srwatsonip_srcroute(struct mbuf *m0) 403152592Sandre{ 404169464Srwatson struct in_addr *p, *q; 405169464Srwatson struct mbuf *m; 406152592Sandre struct ipopt_tag *opts; 407152592Sandre 408152592Sandre opts = (struct ipopt_tag *)m_tag_find(m0, PACKET_TAG_IPOPTIONS, NULL); 409152592Sandre if (opts == NULL) 410152592Sandre return (NULL); 411152592Sandre 412152592Sandre if (opts->ip_nhops == 0) 413152592Sandre return (NULL); 414152592Sandre m = m_get(M_DONTWAIT, MT_DATA); 415152592Sandre if (m == NULL) 416152592Sandre return (NULL); 417152592Sandre 418152592Sandre#define OPTSIZ (sizeof(opts->ip_srcrt.nop) + sizeof(opts->ip_srcrt.srcopt)) 419152592Sandre 420152592Sandre /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 421152592Sandre m->m_len = opts->ip_nhops * sizeof(struct in_addr) + 422152592Sandre sizeof(struct in_addr) + OPTSIZ; 423152592Sandre 424152592Sandre /* 425169464Srwatson * First, save first hop for return route. 426152592Sandre */ 427152592Sandre p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]); 428152592Sandre *(mtod(m, struct in_addr *)) = *p--; 429152592Sandre 430152592Sandre /* 431152592Sandre * Copy option fields and padding (nop) to mbuf. 432152592Sandre */ 433152592Sandre opts->ip_srcrt.nop = IPOPT_NOP; 434152592Sandre opts->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 435152592Sandre (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 436152592Sandre &(opts->ip_srcrt.nop), OPTSIZ); 437152592Sandre q = (struct in_addr *)(mtod(m, caddr_t) + 438152592Sandre sizeof(struct in_addr) + OPTSIZ); 439152592Sandre#undef OPTSIZ 440152592Sandre /* 441169464Srwatson * Record return path as an IP source route, reversing the path 442169464Srwatson * (pointers are now aligned). 443152592Sandre */ 444152592Sandre while (p >= opts->ip_srcrt.route) { 445152592Sandre *q++ = *p--; 446152592Sandre } 447152592Sandre /* 448152592Sandre * Last hop goes to final destination. 449152592Sandre */ 450152592Sandre *q = opts->ip_srcrt.dst; 451152592Sandre m_tag_delete(m0, (struct m_tag *)opts); 452152592Sandre return (m); 453152592Sandre} 454152592Sandre 455152592Sandre/* 456169464Srwatson * Strip out IP options, at higher level protocol in the kernel. Second 457169464Srwatson * argument is buffer to which options will be moved, and return value is 458169464Srwatson * their length. 459169464Srwatson * 460152592Sandre * XXX should be deleted; last arg currently ignored. 461152592Sandre */ 462152592Sandrevoid 463169454Srwatsonip_stripoptions(struct mbuf *m, struct mbuf *mopt) 464152592Sandre{ 465169464Srwatson int i; 466152592Sandre struct ip *ip = mtod(m, struct ip *); 467169464Srwatson caddr_t opts; 468152592Sandre int olen; 469152592Sandre 470152592Sandre olen = (ip->ip_hl << 2) - sizeof (struct ip); 471152592Sandre opts = (caddr_t)(ip + 1); 472152592Sandre i = m->m_len - (sizeof (struct ip) + olen); 473152592Sandre bcopy(opts + olen, opts, (unsigned)i); 474152592Sandre m->m_len -= olen; 475152592Sandre if (m->m_flags & M_PKTHDR) 476152592Sandre m->m_pkthdr.len -= olen; 477152592Sandre ip->ip_v = IPVERSION; 478152592Sandre ip->ip_hl = sizeof(struct ip) >> 2; 479152592Sandre} 480152592Sandre 481152592Sandre/* 482169464Srwatson * Insert IP options into preformed packet. Adjust IP destination as 483169464Srwatson * required for IP source routing, as indicated by a non-zero in_addr at the 484169464Srwatson * start of the options. 485152592Sandre * 486152592Sandre * XXX This routine assumes that the packet has no options in place. 487152592Sandre */ 488152592Sandrestruct mbuf * 489169454Srwatsonip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen) 490152592Sandre{ 491169464Srwatson struct ipoption *p = mtod(opt, struct ipoption *); 492152592Sandre struct mbuf *n; 493169464Srwatson struct ip *ip = mtod(m, struct ip *); 494152592Sandre unsigned optlen; 495152592Sandre 496152592Sandre optlen = opt->m_len - sizeof(p->ipopt_dst); 497152592Sandre if (optlen + ip->ip_len > IP_MAXPACKET) { 498152592Sandre *phlen = 0; 499152592Sandre return (m); /* XXX should fail */ 500152592Sandre } 501152592Sandre if (p->ipopt_dst.s_addr) 502152592Sandre ip->ip_dst = p->ipopt_dst; 503152592Sandre if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) { 504152592Sandre MGETHDR(n, M_DONTWAIT, MT_DATA); 505152592Sandre if (n == NULL) { 506152592Sandre *phlen = 0; 507152592Sandre return (m); 508152592Sandre } 509152592Sandre M_MOVE_PKTHDR(n, m); 510152592Sandre n->m_pkthdr.rcvif = NULL; 511152592Sandre n->m_pkthdr.len += optlen; 512152592Sandre m->m_len -= sizeof(struct ip); 513152592Sandre m->m_data += sizeof(struct ip); 514152592Sandre n->m_next = m; 515152592Sandre m = n; 516152592Sandre m->m_len = optlen + sizeof(struct ip); 517152592Sandre m->m_data += max_linkhdr; 518152592Sandre bcopy(ip, mtod(m, void *), sizeof(struct ip)); 519152592Sandre } else { 520152592Sandre m->m_data -= optlen; 521152592Sandre m->m_len += optlen; 522152592Sandre m->m_pkthdr.len += optlen; 523152592Sandre bcopy(ip, mtod(m, void *), sizeof(struct ip)); 524152592Sandre } 525152592Sandre ip = mtod(m, struct ip *); 526152592Sandre bcopy(p->ipopt_list, ip + 1, optlen); 527152592Sandre *phlen = sizeof(struct ip) + optlen; 528152592Sandre ip->ip_v = IPVERSION; 529152592Sandre ip->ip_hl = *phlen >> 2; 530152592Sandre ip->ip_len += optlen; 531152592Sandre return (m); 532152592Sandre} 533152592Sandre 534152592Sandre/* 535169464Srwatson * Copy options from ip to jp, omitting those not copied during 536169464Srwatson * fragmentation. 537152592Sandre */ 538152592Sandreint 539169454Srwatsonip_optcopy(struct ip *ip, struct ip *jp) 540152592Sandre{ 541169464Srwatson u_char *cp, *dp; 542152592Sandre int opt, optlen, cnt; 543152592Sandre 544152592Sandre cp = (u_char *)(ip + 1); 545152592Sandre dp = (u_char *)(jp + 1); 546152592Sandre cnt = (ip->ip_hl << 2) - sizeof (struct ip); 547152592Sandre for (; cnt > 0; cnt -= optlen, cp += optlen) { 548152592Sandre opt = cp[0]; 549152592Sandre if (opt == IPOPT_EOL) 550152592Sandre break; 551152592Sandre if (opt == IPOPT_NOP) { 552152592Sandre /* Preserve for IP mcast tunnel's LSRR alignment. */ 553152592Sandre *dp++ = IPOPT_NOP; 554152592Sandre optlen = 1; 555152592Sandre continue; 556152592Sandre } 557152592Sandre 558152592Sandre KASSERT(cnt >= IPOPT_OLEN + sizeof(*cp), 559152592Sandre ("ip_optcopy: malformed ipv4 option")); 560152592Sandre optlen = cp[IPOPT_OLEN]; 561152592Sandre KASSERT(optlen >= IPOPT_OLEN + sizeof(*cp) && optlen <= cnt, 562152592Sandre ("ip_optcopy: malformed ipv4 option")); 563152592Sandre 564169464Srwatson /* Bogus lengths should have been caught by ip_dooptions. */ 565152592Sandre if (optlen > cnt) 566152592Sandre optlen = cnt; 567152592Sandre if (IPOPT_COPIED(opt)) { 568152592Sandre bcopy(cp, dp, optlen); 569152592Sandre dp += optlen; 570152592Sandre } 571152592Sandre } 572152592Sandre for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 573152592Sandre *dp++ = IPOPT_EOL; 574152592Sandre return (optlen); 575152592Sandre} 576152592Sandre 577152592Sandre/* 578169464Srwatson * Set up IP options in pcb for insertion in output packets. Store in mbuf 579169464Srwatson * with pointer in pcbopt, adding pseudo-option with destination address if 580169464Srwatson * source routed. 581152592Sandre */ 582152592Sandreint 583152592Sandreip_pcbopts(struct inpcb *inp, int optname, struct mbuf *m) 584152592Sandre{ 585169464Srwatson int cnt, optlen; 586169464Srwatson u_char *cp; 587152592Sandre struct mbuf **pcbopt; 588152592Sandre u_char opt; 589152592Sandre 590178285Srwatson INP_WLOCK_ASSERT(inp); 591152592Sandre 592152592Sandre pcbopt = &inp->inp_options; 593152592Sandre 594152592Sandre /* turn off any old options */ 595152592Sandre if (*pcbopt) 596152592Sandre (void)m_free(*pcbopt); 597152592Sandre *pcbopt = 0; 598152592Sandre if (m == NULL || m->m_len == 0) { 599152592Sandre /* 600152592Sandre * Only turning off any previous options. 601152592Sandre */ 602152592Sandre if (m != NULL) 603152592Sandre (void)m_free(m); 604152592Sandre return (0); 605152592Sandre } 606152592Sandre 607152592Sandre if (m->m_len % sizeof(int32_t)) 608152592Sandre goto bad; 609152592Sandre /* 610169464Srwatson * IP first-hop destination address will be stored before actual 611169464Srwatson * options; move other options back and clear it when none present. 612152592Sandre */ 613152592Sandre if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN]) 614152592Sandre goto bad; 615152592Sandre cnt = m->m_len; 616152592Sandre m->m_len += sizeof(struct in_addr); 617152592Sandre cp = mtod(m, u_char *) + sizeof(struct in_addr); 618152592Sandre bcopy(mtod(m, void *), cp, (unsigned)cnt); 619152592Sandre bzero(mtod(m, void *), sizeof(struct in_addr)); 620152592Sandre 621152592Sandre for (; cnt > 0; cnt -= optlen, cp += optlen) { 622152592Sandre opt = cp[IPOPT_OPTVAL]; 623152592Sandre if (opt == IPOPT_EOL) 624152592Sandre break; 625152592Sandre if (opt == IPOPT_NOP) 626152592Sandre optlen = 1; 627152592Sandre else { 628152592Sandre if (cnt < IPOPT_OLEN + sizeof(*cp)) 629152592Sandre goto bad; 630152592Sandre optlen = cp[IPOPT_OLEN]; 631152592Sandre if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) 632152592Sandre goto bad; 633152592Sandre } 634152592Sandre switch (opt) { 635152592Sandre 636152592Sandre default: 637152592Sandre break; 638152592Sandre 639152592Sandre case IPOPT_LSRR: 640152592Sandre case IPOPT_SSRR: 641152592Sandre /* 642169464Srwatson * User process specifies route as: 643169464Srwatson * 644152592Sandre * ->A->B->C->D 645169464Srwatson * 646152592Sandre * D must be our final destination (but we can't 647152592Sandre * check that since we may not have connected yet). 648169464Srwatson * A is first hop destination, which doesn't appear 649169464Srwatson * in actual IP option, but is stored before the 650169464Srwatson * options. 651152592Sandre */ 652175630Sbz /* XXX-BZ PRIV_NETINET_SETHDROPTS? */ 653152592Sandre if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr)) 654152592Sandre goto bad; 655152592Sandre m->m_len -= sizeof(struct in_addr); 656152592Sandre cnt -= sizeof(struct in_addr); 657152592Sandre optlen -= sizeof(struct in_addr); 658152592Sandre cp[IPOPT_OLEN] = optlen; 659152592Sandre /* 660152592Sandre * Move first hop before start of options. 661152592Sandre */ 662152592Sandre bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t), 663152592Sandre sizeof(struct in_addr)); 664152592Sandre /* 665152592Sandre * Then copy rest of options back 666152592Sandre * to close up the deleted entry. 667152592Sandre */ 668152592Sandre bcopy((&cp[IPOPT_OFFSET+1] + sizeof(struct in_addr)), 669152592Sandre &cp[IPOPT_OFFSET+1], 670152592Sandre (unsigned)cnt - (IPOPT_MINOFF - 1)); 671152592Sandre break; 672152592Sandre } 673152592Sandre } 674152592Sandre if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr)) 675152592Sandre goto bad; 676152592Sandre *pcbopt = m; 677152592Sandre return (0); 678152592Sandre 679152592Sandrebad: 680152592Sandre (void)m_free(m); 681152592Sandre return (EINVAL); 682152592Sandre} 683189343Sbms 684189343Sbms/* 685189343Sbms * Check for the presence of the IP Router Alert option [RFC2113] 686189343Sbms * in the header of an IPv4 datagram. 687189343Sbms * 688189343Sbms * This call is not intended for use from the forwarding path; it is here 689189343Sbms * so that protocol domains may check for the presence of the option. 690189343Sbms * Given how FreeBSD's IPv4 stack is currently structured, the Router Alert 691189343Sbms * option does not have much relevance to the implementation, though this 692189343Sbms * may change in future. 693189343Sbms * Router alert options SHOULD be passed if running in IPSTEALTH mode and 694189343Sbms * we are not the endpoint. 695189343Sbms * Length checks on individual options should already have been peformed 696189343Sbms * by ip_dooptions() therefore they are folded under INVARIANTS here. 697189343Sbms * 698189343Sbms * Return zero if not present or options are invalid, non-zero if present. 699189343Sbms */ 700189343Sbmsint 701189343Sbmsip_checkrouteralert(struct mbuf *m) 702189343Sbms{ 703189343Sbms struct ip *ip = mtod(m, struct ip *); 704189343Sbms u_char *cp; 705189343Sbms int opt, optlen, cnt, found_ra; 706189343Sbms 707189343Sbms found_ra = 0; 708189343Sbms cp = (u_char *)(ip + 1); 709189343Sbms cnt = (ip->ip_hl << 2) - sizeof (struct ip); 710189343Sbms for (; cnt > 0; cnt -= optlen, cp += optlen) { 711189343Sbms opt = cp[IPOPT_OPTVAL]; 712189343Sbms if (opt == IPOPT_EOL) 713189343Sbms break; 714189343Sbms if (opt == IPOPT_NOP) 715189343Sbms optlen = 1; 716189343Sbms else { 717189343Sbms#ifdef INVARIANTS 718189343Sbms if (cnt < IPOPT_OLEN + sizeof(*cp)) 719189343Sbms break; 720189343Sbms#endif 721189343Sbms optlen = cp[IPOPT_OLEN]; 722189343Sbms#ifdef INVARIANTS 723189343Sbms if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) 724189343Sbms break; 725189343Sbms#endif 726189343Sbms } 727189343Sbms switch (opt) { 728189343Sbms case IPOPT_RA: 729189343Sbms#ifdef INVARIANTS 730189343Sbms if (optlen != IPOPT_OFFSET + sizeof(uint16_t) || 731189343Sbms (*((uint16_t *)&cp[IPOPT_OFFSET]) != 0)) 732189343Sbms break; 733189343Sbms else 734189343Sbms#endif 735189343Sbms found_ra = 1; 736189343Sbms break; 737189343Sbms default: 738189343Sbms break; 739189343Sbms } 740189343Sbms } 741189343Sbms 742189343Sbms return (found_ra); 743189343Sbms} 744