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: stable/11/sys/netinet/ip_options.c 315456 2017-03-17 14:54:10Z vangyzen $"); 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> 57291993Smelifaro#include <netinet/in_fib.h> 58152592Sandre#include <netinet/in_systm.h> 59152592Sandre#include <netinet/in_var.h> 60152592Sandre#include <netinet/ip.h> 61152592Sandre#include <netinet/in_pcb.h> 62152592Sandre#include <netinet/ip_var.h> 63152592Sandre#include <netinet/ip_options.h> 64152592Sandre#include <netinet/ip_icmp.h> 65152592Sandre#include <machine/in_cksum.h> 66152592Sandre 67152592Sandre#include <sys/socketvar.h> 68152592Sandre 69271610Shrsstatic VNET_DEFINE(int, ip_dosourceroute); 70271628ShrsSYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, 71271628Shrs CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip_dosourceroute), 0, 72271610Shrs "Enable forwarding source routed IP packets"); 73271610Shrs#define V_ip_dosourceroute VNET(ip_dosourceroute) 74152592Sandre 75271610Shrsstatic VNET_DEFINE(int, ip_acceptsourceroute); 76271628ShrsSYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 77271628Shrs CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip_acceptsourceroute), 0, 78152592Sandre "Enable accepting source routed IP packets"); 79271610Shrs#define V_ip_acceptsourceroute VNET(ip_acceptsourceroute) 80152592Sandre 81271610ShrsVNET_DEFINE(int, ip_doopts) = 1; /* 0 = ignore, 1 = process, 2 = reject */ 82271628ShrsSYSCTL_INT(_net_inet_ip, OID_AUTO, process_options, CTLFLAG_VNET | CTLFLAG_RW, 83271610Shrs &VNET_NAME(ip_doopts), 0, "Enable IP options processing ([LS]SRR, RR, TS)"); 84152592Sandre 85152592Sandrestatic void save_rte(struct mbuf *m, u_char *, struct in_addr); 86152592Sandre 87152592Sandre/* 88169464Srwatson * Do option processing on a datagram, possibly discarding it if bad options 89169464Srwatson * are encountered, or forwarding it if source-routed. 90169464Srwatson * 91169464Srwatson * The pass argument is used when operating in the IPSTEALTH mode to tell 92169464Srwatson * what options to process: [LS]SRR (pass 0) or the others (pass 1). The 93169464Srwatson * reason for as many as two passes is that when doing IPSTEALTH, non-routing 94169464Srwatson * options should be processed only if the packet is for us. 95169464Srwatson * 96169464Srwatson * Returns 1 if packet has been forwarded/freed, 0 if the packet should be 97169464Srwatson * processed further. 98152592Sandre */ 99152592Sandreint 100152592Sandreip_dooptions(struct mbuf *m, int pass) 101152592Sandre{ 102152592Sandre struct ip *ip = mtod(m, struct ip *); 103152592Sandre u_char *cp; 104152592Sandre struct in_ifaddr *ia; 105152592Sandre int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 106152592Sandre struct in_addr *sin, dst; 107188578Sluigi uint32_t ntime; 108291993Smelifaro struct nhop4_extended nh_ext; 109152592Sandre struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 110152592Sandre 111169464Srwatson /* Ignore or reject packets with IP options. */ 112271610Shrs if (V_ip_doopts == 0) 113152592Sandre return 0; 114271610Shrs else if (V_ip_doopts == 2) { 115152592Sandre type = ICMP_UNREACH; 116152592Sandre code = ICMP_UNREACH_FILTER_PROHIB; 117152592Sandre goto bad; 118152592Sandre } 119152592Sandre 120152592Sandre dst = ip->ip_dst; 121152592Sandre cp = (u_char *)(ip + 1); 122152592Sandre cnt = (ip->ip_hl << 2) - sizeof (struct ip); 123152592Sandre for (; cnt > 0; cnt -= optlen, cp += optlen) { 124152592Sandre opt = cp[IPOPT_OPTVAL]; 125152592Sandre if (opt == IPOPT_EOL) 126152592Sandre break; 127152592Sandre if (opt == IPOPT_NOP) 128152592Sandre optlen = 1; 129152592Sandre else { 130152592Sandre if (cnt < IPOPT_OLEN + sizeof(*cp)) { 131152592Sandre code = &cp[IPOPT_OLEN] - (u_char *)ip; 132152592Sandre goto bad; 133152592Sandre } 134152592Sandre optlen = cp[IPOPT_OLEN]; 135152592Sandre if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 136152592Sandre code = &cp[IPOPT_OLEN] - (u_char *)ip; 137152592Sandre goto bad; 138152592Sandre } 139152592Sandre } 140152592Sandre switch (opt) { 141152592Sandre 142152592Sandre default: 143152592Sandre break; 144152592Sandre 145152592Sandre /* 146169464Srwatson * Source routing with record. Find interface with current 147169464Srwatson * destination address. If none on this machine then drop if 148169464Srwatson * strictly routed, or do nothing if loosely routed. Record 149169464Srwatson * interface address and bring up next address component. If 150169464Srwatson * strictly routed make sure next address is on directly 151169464Srwatson * accessible net. 152152592Sandre */ 153152592Sandre case IPOPT_LSRR: 154152592Sandre case IPOPT_SSRR: 155152592Sandre#ifdef IPSTEALTH 156181803Sbz if (V_ipstealth && pass > 0) 157152592Sandre break; 158152592Sandre#endif 159152592Sandre if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 160152592Sandre code = &cp[IPOPT_OLEN] - (u_char *)ip; 161152592Sandre goto bad; 162152592Sandre } 163152592Sandre if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 164152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 165152592Sandre goto bad; 166152592Sandre } 167152592Sandre ipaddr.sin_addr = ip->ip_dst; 168194760Srwatson if (ifa_ifwithaddr_check((struct sockaddr *)&ipaddr) 169194760Srwatson == 0) { 170152592Sandre if (opt == IPOPT_SSRR) { 171152592Sandre type = ICMP_UNREACH; 172152592Sandre code = ICMP_UNREACH_SRCFAIL; 173152592Sandre goto bad; 174152592Sandre } 175271610Shrs if (!V_ip_dosourceroute) 176152592Sandre goto nosourcerouting; 177152592Sandre /* 178152592Sandre * Loose routing, and not at next destination 179152592Sandre * yet; nothing to do except forward. 180152592Sandre */ 181152592Sandre break; 182152592Sandre } 183152592Sandre off--; /* 0 origin */ 184152592Sandre if (off > optlen - (int)sizeof(struct in_addr)) { 185152592Sandre /* 186152592Sandre * End of source route. Should be for us. 187152592Sandre */ 188271610Shrs if (!V_ip_acceptsourceroute) 189152592Sandre goto nosourcerouting; 190152592Sandre save_rte(m, cp, ip->ip_src); 191152592Sandre break; 192152592Sandre } 193152592Sandre#ifdef IPSTEALTH 194181803Sbz if (V_ipstealth) 195152592Sandre goto dropit; 196152592Sandre#endif 197271610Shrs if (!V_ip_dosourceroute) { 198181803Sbz if (V_ipforwarding) { 199315456Svangyzen char srcbuf[INET_ADDRSTRLEN]; 200315456Svangyzen char dstbuf[INET_ADDRSTRLEN]; 201315456Svangyzen 202152592Sandre /* 203169464Srwatson * Acting as a router, so generate 204169464Srwatson * ICMP 205152592Sandre */ 206152592Sandrenosourcerouting: 207152592Sandre log(LOG_WARNING, 208315456Svangyzen "attempted source route from %s " 209315456Svangyzen "to %s\n", 210315456Svangyzen inet_ntoa_r(ip->ip_src, srcbuf), 211315456Svangyzen inet_ntoa_r(ip->ip_dst, dstbuf)); 212152592Sandre type = ICMP_UNREACH; 213152592Sandre code = ICMP_UNREACH_SRCFAIL; 214152592Sandre goto bad; 215152592Sandre } else { 216152592Sandre /* 217169464Srwatson * Not acting as a router, so 218169464Srwatson * silently drop. 219152592Sandre */ 220152592Sandre#ifdef IPSTEALTH 221152592Sandredropit: 222152592Sandre#endif 223190951Srwatson IPSTAT_INC(ips_cantforward); 224152592Sandre m_freem(m); 225152592Sandre return (1); 226152592Sandre } 227152592Sandre } 228152592Sandre 229152592Sandre /* 230152592Sandre * locate outgoing interface 231152592Sandre */ 232152592Sandre (void)memcpy(&ipaddr.sin_addr, cp + off, 233152592Sandre sizeof(ipaddr.sin_addr)); 234152592Sandre 235291993Smelifaro type = ICMP_UNREACH; 236291993Smelifaro code = ICMP_UNREACH_SRCFAIL; 237291993Smelifaro 238152592Sandre if (opt == IPOPT_SSRR) { 239152592Sandre#define INA struct in_ifaddr * 240152592Sandre#define SA struct sockaddr * 241271438Sasomers ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr, 242271438Sasomers RT_ALL_FIBS); 243271438Sasomers if (ia == NULL) 244271438Sasomers ia = (INA)ifa_ifwithnet((SA)&ipaddr, 0, 245271438Sasomers RT_ALL_FIBS); 246291993Smelifaro if (ia == NULL) 247291993Smelifaro goto bad; 248291993Smelifaro 249291993Smelifaro memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 250291993Smelifaro sizeof(struct in_addr)); 251291993Smelifaro ifa_free(&ia->ia_ifa); 252291993Smelifaro } else { 253291993Smelifaro /* XXX MRT 0 for routing */ 254291993Smelifaro if (fib4_lookup_nh_ext(M_GETFIB(m), 255291993Smelifaro ipaddr.sin_addr, 0, 0, &nh_ext) != 0) 256291993Smelifaro goto bad; 257291993Smelifaro 258291993Smelifaro memcpy(cp + off, &nh_ext.nh_src, 259291993Smelifaro sizeof(struct in_addr)); 260152592Sandre } 261291993Smelifaro 262152592Sandre ip->ip_dst = ipaddr.sin_addr; 263152592Sandre cp[IPOPT_OFFSET] += sizeof(struct in_addr); 264152592Sandre /* 265152592Sandre * Let ip_intr's mcast routing check handle mcast pkts 266152592Sandre */ 267152592Sandre forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 268152592Sandre break; 269152592Sandre 270152592Sandre case IPOPT_RR: 271152592Sandre#ifdef IPSTEALTH 272181803Sbz if (V_ipstealth && pass == 0) 273152592Sandre break; 274152592Sandre#endif 275152592Sandre if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 276152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 277152592Sandre goto bad; 278152592Sandre } 279152592Sandre if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 280152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 281152592Sandre goto bad; 282152592Sandre } 283152592Sandre /* 284152592Sandre * If no space remains, ignore. 285152592Sandre */ 286152592Sandre off--; /* 0 origin */ 287152592Sandre if (off > optlen - (int)sizeof(struct in_addr)) 288152592Sandre break; 289152592Sandre (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 290152592Sandre sizeof(ipaddr.sin_addr)); 291152592Sandre /* 292169464Srwatson * Locate outgoing interface; if we're the 293169464Srwatson * destination, use the incoming interface (should be 294169464Srwatson * same). 295152592Sandre */ 296292015Smelifaro if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) != NULL) { 297292015Smelifaro memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 298292015Smelifaro sizeof(struct in_addr)); 299292015Smelifaro ifa_free(&ia->ia_ifa); 300292015Smelifaro } else if (fib4_lookup_nh_ext(M_GETFIB(m), 301292015Smelifaro ipaddr.sin_addr, 0, 0, &nh_ext) == 0) { 302292015Smelifaro memcpy(cp + off, &nh_ext.nh_src, 303292015Smelifaro sizeof(struct in_addr)); 304292015Smelifaro } else { 305152592Sandre type = ICMP_UNREACH; 306152592Sandre code = ICMP_UNREACH_HOST; 307152592Sandre goto bad; 308152592Sandre } 309152592Sandre cp[IPOPT_OFFSET] += sizeof(struct in_addr); 310152592Sandre break; 311152592Sandre 312152592Sandre case IPOPT_TS: 313152592Sandre#ifdef IPSTEALTH 314181803Sbz if (V_ipstealth && pass == 0) 315152592Sandre break; 316152592Sandre#endif 317152592Sandre code = cp - (u_char *)ip; 318152592Sandre if (optlen < 4 || optlen > 40) { 319152592Sandre code = &cp[IPOPT_OLEN] - (u_char *)ip; 320152592Sandre goto bad; 321152592Sandre } 322152592Sandre if ((off = cp[IPOPT_OFFSET]) < 5) { 323152592Sandre code = &cp[IPOPT_OLEN] - (u_char *)ip; 324152592Sandre goto bad; 325152592Sandre } 326152592Sandre if (off > optlen - (int)sizeof(int32_t)) { 327152592Sandre cp[IPOPT_OFFSET + 1] += (1 << 4); 328152592Sandre if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 329152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 330152592Sandre goto bad; 331152592Sandre } 332152592Sandre break; 333152592Sandre } 334152592Sandre off--; /* 0 origin */ 335152592Sandre sin = (struct in_addr *)(cp + off); 336152592Sandre switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 337152592Sandre 338152592Sandre case IPOPT_TS_TSONLY: 339152592Sandre break; 340152592Sandre 341152592Sandre case IPOPT_TS_TSANDADDR: 342188578Sluigi if (off + sizeof(uint32_t) + 343152592Sandre sizeof(struct in_addr) > optlen) { 344152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 345152592Sandre goto bad; 346152592Sandre } 347152592Sandre ipaddr.sin_addr = dst; 348152592Sandre ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 349152592Sandre m->m_pkthdr.rcvif); 350152592Sandre if (ia == NULL) 351152592Sandre continue; 352152592Sandre (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 353152592Sandre sizeof(struct in_addr)); 354194760Srwatson ifa_free(&ia->ia_ifa); 355152592Sandre cp[IPOPT_OFFSET] += sizeof(struct in_addr); 356152592Sandre off += sizeof(struct in_addr); 357152592Sandre break; 358152592Sandre 359152592Sandre case IPOPT_TS_PRESPEC: 360188578Sluigi if (off + sizeof(uint32_t) + 361152592Sandre sizeof(struct in_addr) > optlen) { 362152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 363152592Sandre goto bad; 364152592Sandre } 365152592Sandre (void)memcpy(&ipaddr.sin_addr, sin, 366152592Sandre sizeof(struct in_addr)); 367213832Sbz if (ifa_ifwithaddr_check((SA)&ipaddr) == 0) 368152592Sandre continue; 369152592Sandre cp[IPOPT_OFFSET] += sizeof(struct in_addr); 370152592Sandre off += sizeof(struct in_addr); 371152592Sandre break; 372152592Sandre 373152592Sandre default: 374152592Sandre code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 375152592Sandre goto bad; 376152592Sandre } 377152592Sandre ntime = iptime(); 378188578Sluigi (void)memcpy(cp + off, &ntime, sizeof(uint32_t)); 379188578Sluigi cp[IPOPT_OFFSET] += sizeof(uint32_t); 380152592Sandre } 381152592Sandre } 382181803Sbz if (forward && V_ipforwarding) { 383152592Sandre ip_forward(m, 1); 384152592Sandre return (1); 385152592Sandre } 386152592Sandre return (0); 387152592Sandrebad: 388152592Sandre icmp_error(m, type, code, 0, 0); 389190951Srwatson IPSTAT_INC(ips_badoptions); 390152592Sandre return (1); 391152592Sandre} 392152592Sandre 393152592Sandre/* 394169464Srwatson * Save incoming source route for use in replies, to be picked up later by 395169464Srwatson * ip_srcroute if the receiver is interested. 396152592Sandre */ 397152592Sandrestatic void 398169454Srwatsonsave_rte(struct mbuf *m, u_char *option, struct in_addr dst) 399152592Sandre{ 400152592Sandre unsigned olen; 401152592Sandre struct ipopt_tag *opts; 402152592Sandre 403152592Sandre opts = (struct ipopt_tag *)m_tag_get(PACKET_TAG_IPOPTIONS, 404169464Srwatson sizeof(struct ipopt_tag), M_NOWAIT); 405152592Sandre if (opts == NULL) 406152592Sandre return; 407152592Sandre 408152592Sandre olen = option[IPOPT_OLEN]; 409152592Sandre if (olen > sizeof(opts->ip_srcrt) - (1 + sizeof(dst))) { 410152592Sandre m_tag_free((struct m_tag *)opts); 411152592Sandre return; 412152592Sandre } 413152592Sandre bcopy(option, opts->ip_srcrt.srcopt, olen); 414152592Sandre opts->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 415152592Sandre opts->ip_srcrt.dst = dst; 416152592Sandre m_tag_prepend(m, (struct m_tag *)opts); 417152592Sandre} 418152592Sandre 419152592Sandre/* 420169464Srwatson * Retrieve incoming source route for use in replies, in the same form used 421169464Srwatson * by setsockopt. The first hop is placed before the options, will be 422169464Srwatson * removed later. 423152592Sandre */ 424152592Sandrestruct mbuf * 425169454Srwatsonip_srcroute(struct mbuf *m0) 426152592Sandre{ 427169464Srwatson struct in_addr *p, *q; 428169464Srwatson struct mbuf *m; 429152592Sandre struct ipopt_tag *opts; 430152592Sandre 431152592Sandre opts = (struct ipopt_tag *)m_tag_find(m0, PACKET_TAG_IPOPTIONS, NULL); 432152592Sandre if (opts == NULL) 433152592Sandre return (NULL); 434152592Sandre 435152592Sandre if (opts->ip_nhops == 0) 436152592Sandre return (NULL); 437243882Sglebius m = m_get(M_NOWAIT, MT_DATA); 438152592Sandre if (m == NULL) 439152592Sandre return (NULL); 440152592Sandre 441152592Sandre#define OPTSIZ (sizeof(opts->ip_srcrt.nop) + sizeof(opts->ip_srcrt.srcopt)) 442152592Sandre 443152592Sandre /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 444152592Sandre m->m_len = opts->ip_nhops * sizeof(struct in_addr) + 445152592Sandre sizeof(struct in_addr) + OPTSIZ; 446152592Sandre 447152592Sandre /* 448169464Srwatson * First, save first hop for return route. 449152592Sandre */ 450152592Sandre p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]); 451152592Sandre *(mtod(m, struct in_addr *)) = *p--; 452152592Sandre 453152592Sandre /* 454152592Sandre * Copy option fields and padding (nop) to mbuf. 455152592Sandre */ 456152592Sandre opts->ip_srcrt.nop = IPOPT_NOP; 457152592Sandre opts->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 458152592Sandre (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 459152592Sandre &(opts->ip_srcrt.nop), OPTSIZ); 460152592Sandre q = (struct in_addr *)(mtod(m, caddr_t) + 461152592Sandre sizeof(struct in_addr) + OPTSIZ); 462152592Sandre#undef OPTSIZ 463152592Sandre /* 464169464Srwatson * Record return path as an IP source route, reversing the path 465169464Srwatson * (pointers are now aligned). 466152592Sandre */ 467152592Sandre while (p >= opts->ip_srcrt.route) { 468152592Sandre *q++ = *p--; 469152592Sandre } 470152592Sandre /* 471152592Sandre * Last hop goes to final destination. 472152592Sandre */ 473152592Sandre *q = opts->ip_srcrt.dst; 474152592Sandre m_tag_delete(m0, (struct m_tag *)opts); 475152592Sandre return (m); 476152592Sandre} 477152592Sandre 478152592Sandre/* 479241480Sglebius * Strip out IP options, at higher level protocol in the kernel. 480152592Sandre */ 481152592Sandrevoid 482241480Sglebiusip_stripoptions(struct mbuf *m) 483152592Sandre{ 484152592Sandre struct ip *ip = mtod(m, struct ip *); 485152592Sandre int olen; 486152592Sandre 487241925Sglebius olen = (ip->ip_hl << 2) - sizeof(struct ip); 488152592Sandre m->m_len -= olen; 489152592Sandre if (m->m_flags & M_PKTHDR) 490152592Sandre m->m_pkthdr.len -= olen; 491241923Sglebius ip->ip_len = htons(ntohs(ip->ip_len) - olen); 492152592Sandre ip->ip_hl = sizeof(struct ip) >> 2; 493241925Sglebius 494241925Sglebius bcopy((char *)ip + sizeof(struct ip) + olen, (ip + 1), 495241925Sglebius (size_t )(m->m_len - sizeof(struct ip))); 496152592Sandre} 497152592Sandre 498152592Sandre/* 499169464Srwatson * Insert IP options into preformed packet. Adjust IP destination as 500169464Srwatson * required for IP source routing, as indicated by a non-zero in_addr at the 501169464Srwatson * start of the options. 502152592Sandre * 503152592Sandre * XXX This routine assumes that the packet has no options in place. 504152592Sandre */ 505152592Sandrestruct mbuf * 506169454Srwatsonip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen) 507152592Sandre{ 508169464Srwatson struct ipoption *p = mtod(opt, struct ipoption *); 509152592Sandre struct mbuf *n; 510169464Srwatson struct ip *ip = mtod(m, struct ip *); 511152592Sandre unsigned optlen; 512152592Sandre 513152592Sandre optlen = opt->m_len - sizeof(p->ipopt_dst); 514241913Sglebius if (optlen + ntohs(ip->ip_len) > IP_MAXPACKET) { 515152592Sandre *phlen = 0; 516152592Sandre return (m); /* XXX should fail */ 517152592Sandre } 518152592Sandre if (p->ipopt_dst.s_addr) 519152592Sandre ip->ip_dst = p->ipopt_dst; 520276752Srwatson if (!M_WRITABLE(m) || M_LEADINGSPACE(m) < optlen) { 521248324Sglebius n = m_gethdr(M_NOWAIT, MT_DATA); 522152592Sandre if (n == NULL) { 523152592Sandre *phlen = 0; 524152592Sandre return (m); 525152592Sandre } 526248373Sglebius m_move_pkthdr(n, m); 527152592Sandre n->m_pkthdr.rcvif = NULL; 528152592Sandre n->m_pkthdr.len += optlen; 529152592Sandre m->m_len -= sizeof(struct ip); 530152592Sandre m->m_data += sizeof(struct ip); 531152592Sandre n->m_next = m; 532152592Sandre m = n; 533152592Sandre m->m_len = optlen + sizeof(struct ip); 534152592Sandre m->m_data += max_linkhdr; 535152592Sandre bcopy(ip, mtod(m, void *), sizeof(struct ip)); 536152592Sandre } else { 537152592Sandre m->m_data -= optlen; 538152592Sandre m->m_len += optlen; 539152592Sandre m->m_pkthdr.len += optlen; 540152592Sandre bcopy(ip, mtod(m, void *), sizeof(struct ip)); 541152592Sandre } 542152592Sandre ip = mtod(m, struct ip *); 543152592Sandre bcopy(p->ipopt_list, ip + 1, optlen); 544152592Sandre *phlen = sizeof(struct ip) + optlen; 545152592Sandre ip->ip_v = IPVERSION; 546152592Sandre ip->ip_hl = *phlen >> 2; 547241913Sglebius ip->ip_len = htons(ntohs(ip->ip_len) + optlen); 548152592Sandre return (m); 549152592Sandre} 550152592Sandre 551152592Sandre/* 552169464Srwatson * Copy options from ip to jp, omitting those not copied during 553169464Srwatson * fragmentation. 554152592Sandre */ 555152592Sandreint 556169454Srwatsonip_optcopy(struct ip *ip, struct ip *jp) 557152592Sandre{ 558169464Srwatson u_char *cp, *dp; 559152592Sandre int opt, optlen, cnt; 560152592Sandre 561152592Sandre cp = (u_char *)(ip + 1); 562152592Sandre dp = (u_char *)(jp + 1); 563152592Sandre cnt = (ip->ip_hl << 2) - sizeof (struct ip); 564152592Sandre for (; cnt > 0; cnt -= optlen, cp += optlen) { 565152592Sandre opt = cp[0]; 566152592Sandre if (opt == IPOPT_EOL) 567152592Sandre break; 568152592Sandre if (opt == IPOPT_NOP) { 569152592Sandre /* Preserve for IP mcast tunnel's LSRR alignment. */ 570152592Sandre *dp++ = IPOPT_NOP; 571152592Sandre optlen = 1; 572152592Sandre continue; 573152592Sandre } 574152592Sandre 575152592Sandre KASSERT(cnt >= IPOPT_OLEN + sizeof(*cp), 576152592Sandre ("ip_optcopy: malformed ipv4 option")); 577152592Sandre optlen = cp[IPOPT_OLEN]; 578152592Sandre KASSERT(optlen >= IPOPT_OLEN + sizeof(*cp) && optlen <= cnt, 579152592Sandre ("ip_optcopy: malformed ipv4 option")); 580152592Sandre 581169464Srwatson /* Bogus lengths should have been caught by ip_dooptions. */ 582152592Sandre if (optlen > cnt) 583152592Sandre optlen = cnt; 584152592Sandre if (IPOPT_COPIED(opt)) { 585152592Sandre bcopy(cp, dp, optlen); 586152592Sandre dp += optlen; 587152592Sandre } 588152592Sandre } 589152592Sandre for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 590152592Sandre *dp++ = IPOPT_EOL; 591152592Sandre return (optlen); 592152592Sandre} 593152592Sandre 594152592Sandre/* 595169464Srwatson * Set up IP options in pcb for insertion in output packets. Store in mbuf 596169464Srwatson * with pointer in pcbopt, adding pseudo-option with destination address if 597169464Srwatson * source routed. 598152592Sandre */ 599152592Sandreint 600152592Sandreip_pcbopts(struct inpcb *inp, int optname, struct mbuf *m) 601152592Sandre{ 602169464Srwatson int cnt, optlen; 603169464Srwatson u_char *cp; 604152592Sandre struct mbuf **pcbopt; 605152592Sandre u_char opt; 606152592Sandre 607178285Srwatson INP_WLOCK_ASSERT(inp); 608152592Sandre 609152592Sandre pcbopt = &inp->inp_options; 610152592Sandre 611152592Sandre /* turn off any old options */ 612152592Sandre if (*pcbopt) 613152592Sandre (void)m_free(*pcbopt); 614298066Spfg *pcbopt = NULL; 615152592Sandre if (m == NULL || m->m_len == 0) { 616152592Sandre /* 617152592Sandre * Only turning off any previous options. 618152592Sandre */ 619152592Sandre if (m != NULL) 620152592Sandre (void)m_free(m); 621152592Sandre return (0); 622152592Sandre } 623152592Sandre 624152592Sandre if (m->m_len % sizeof(int32_t)) 625152592Sandre goto bad; 626152592Sandre /* 627169464Srwatson * IP first-hop destination address will be stored before actual 628169464Srwatson * options; move other options back and clear it when none present. 629152592Sandre */ 630152592Sandre if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN]) 631152592Sandre goto bad; 632152592Sandre cnt = m->m_len; 633152592Sandre m->m_len += sizeof(struct in_addr); 634152592Sandre cp = mtod(m, u_char *) + sizeof(struct in_addr); 635152592Sandre bcopy(mtod(m, void *), cp, (unsigned)cnt); 636152592Sandre bzero(mtod(m, void *), sizeof(struct in_addr)); 637152592Sandre 638152592Sandre for (; cnt > 0; cnt -= optlen, cp += optlen) { 639152592Sandre opt = cp[IPOPT_OPTVAL]; 640152592Sandre if (opt == IPOPT_EOL) 641152592Sandre break; 642152592Sandre if (opt == IPOPT_NOP) 643152592Sandre optlen = 1; 644152592Sandre else { 645152592Sandre if (cnt < IPOPT_OLEN + sizeof(*cp)) 646152592Sandre goto bad; 647152592Sandre optlen = cp[IPOPT_OLEN]; 648152592Sandre if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) 649152592Sandre goto bad; 650152592Sandre } 651152592Sandre switch (opt) { 652152592Sandre 653152592Sandre default: 654152592Sandre break; 655152592Sandre 656152592Sandre case IPOPT_LSRR: 657152592Sandre case IPOPT_SSRR: 658152592Sandre /* 659169464Srwatson * User process specifies route as: 660169464Srwatson * 661152592Sandre * ->A->B->C->D 662169464Srwatson * 663152592Sandre * D must be our final destination (but we can't 664152592Sandre * check that since we may not have connected yet). 665169464Srwatson * A is first hop destination, which doesn't appear 666169464Srwatson * in actual IP option, but is stored before the 667169464Srwatson * options. 668152592Sandre */ 669175630Sbz /* XXX-BZ PRIV_NETINET_SETHDROPTS? */ 670152592Sandre if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr)) 671152592Sandre goto bad; 672152592Sandre m->m_len -= sizeof(struct in_addr); 673152592Sandre cnt -= sizeof(struct in_addr); 674152592Sandre optlen -= sizeof(struct in_addr); 675152592Sandre cp[IPOPT_OLEN] = optlen; 676152592Sandre /* 677152592Sandre * Move first hop before start of options. 678152592Sandre */ 679152592Sandre bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t), 680152592Sandre sizeof(struct in_addr)); 681152592Sandre /* 682152592Sandre * Then copy rest of options back 683152592Sandre * to close up the deleted entry. 684152592Sandre */ 685152592Sandre bcopy((&cp[IPOPT_OFFSET+1] + sizeof(struct in_addr)), 686152592Sandre &cp[IPOPT_OFFSET+1], 687152592Sandre (unsigned)cnt - (IPOPT_MINOFF - 1)); 688152592Sandre break; 689152592Sandre } 690152592Sandre } 691152592Sandre if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr)) 692152592Sandre goto bad; 693152592Sandre *pcbopt = m; 694152592Sandre return (0); 695152592Sandre 696152592Sandrebad: 697152592Sandre (void)m_free(m); 698152592Sandre return (EINVAL); 699152592Sandre} 700189343Sbms 701189343Sbms/* 702189343Sbms * Check for the presence of the IP Router Alert option [RFC2113] 703189343Sbms * in the header of an IPv4 datagram. 704189343Sbms * 705189343Sbms * This call is not intended for use from the forwarding path; it is here 706189343Sbms * so that protocol domains may check for the presence of the option. 707189343Sbms * Given how FreeBSD's IPv4 stack is currently structured, the Router Alert 708189343Sbms * option does not have much relevance to the implementation, though this 709189343Sbms * may change in future. 710189343Sbms * Router alert options SHOULD be passed if running in IPSTEALTH mode and 711189343Sbms * we are not the endpoint. 712298995Spfg * Length checks on individual options should already have been performed 713189343Sbms * by ip_dooptions() therefore they are folded under INVARIANTS here. 714189343Sbms * 715189343Sbms * Return zero if not present or options are invalid, non-zero if present. 716189343Sbms */ 717189343Sbmsint 718189343Sbmsip_checkrouteralert(struct mbuf *m) 719189343Sbms{ 720189343Sbms struct ip *ip = mtod(m, struct ip *); 721189343Sbms u_char *cp; 722189343Sbms int opt, optlen, cnt, found_ra; 723189343Sbms 724189343Sbms found_ra = 0; 725189343Sbms cp = (u_char *)(ip + 1); 726189343Sbms cnt = (ip->ip_hl << 2) - sizeof (struct ip); 727189343Sbms for (; cnt > 0; cnt -= optlen, cp += optlen) { 728189343Sbms opt = cp[IPOPT_OPTVAL]; 729189343Sbms if (opt == IPOPT_EOL) 730189343Sbms break; 731189343Sbms if (opt == IPOPT_NOP) 732189343Sbms optlen = 1; 733189343Sbms else { 734189343Sbms#ifdef INVARIANTS 735189343Sbms if (cnt < IPOPT_OLEN + sizeof(*cp)) 736189343Sbms break; 737189343Sbms#endif 738189343Sbms optlen = cp[IPOPT_OLEN]; 739189343Sbms#ifdef INVARIANTS 740189343Sbms if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) 741189343Sbms break; 742189343Sbms#endif 743189343Sbms } 744189343Sbms switch (opt) { 745189343Sbms case IPOPT_RA: 746189343Sbms#ifdef INVARIANTS 747189343Sbms if (optlen != IPOPT_OFFSET + sizeof(uint16_t) || 748189343Sbms (*((uint16_t *)&cp[IPOPT_OFFSET]) != 0)) 749189343Sbms break; 750189343Sbms else 751189343Sbms#endif 752189343Sbms found_ra = 1; 753189343Sbms break; 754189343Sbms default: 755189343Sbms break; 756189343Sbms } 757189343Sbms } 758189343Sbms 759189343Sbms return (found_ra); 760189343Sbms} 761