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: releng/11.0/sys/netinet/ip_options.c 298995 2016-05-03 18:05:43Z pfg $"); 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) { 199152592Sandre char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 200152592Sandre /* 201169464Srwatson * Acting as a router, so generate 202169464Srwatson * ICMP 203152592Sandre */ 204152592Sandrenosourcerouting: 205152592Sandre strcpy(buf, inet_ntoa(ip->ip_dst)); 206152592Sandre log(LOG_WARNING, 207152592Sandre "attempted source route from %s to %s\n", 208152592Sandre inet_ntoa(ip->ip_src), buf); 209152592Sandre type = ICMP_UNREACH; 210152592Sandre code = ICMP_UNREACH_SRCFAIL; 211152592Sandre goto bad; 212152592Sandre } else { 213152592Sandre /* 214169464Srwatson * Not acting as a router, so 215169464Srwatson * silently drop. 216152592Sandre */ 217152592Sandre#ifdef IPSTEALTH 218152592Sandredropit: 219152592Sandre#endif 220190951Srwatson IPSTAT_INC(ips_cantforward); 221152592Sandre m_freem(m); 222152592Sandre return (1); 223152592Sandre } 224152592Sandre } 225152592Sandre 226152592Sandre /* 227152592Sandre * locate outgoing interface 228152592Sandre */ 229152592Sandre (void)memcpy(&ipaddr.sin_addr, cp + off, 230152592Sandre sizeof(ipaddr.sin_addr)); 231152592Sandre 232291993Smelifaro type = ICMP_UNREACH; 233291993Smelifaro code = ICMP_UNREACH_SRCFAIL; 234291993Smelifaro 235152592Sandre if (opt == IPOPT_SSRR) { 236152592Sandre#define INA struct in_ifaddr * 237152592Sandre#define SA struct sockaddr * 238271438Sasomers ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr, 239271438Sasomers RT_ALL_FIBS); 240271438Sasomers if (ia == NULL) 241271438Sasomers ia = (INA)ifa_ifwithnet((SA)&ipaddr, 0, 242271438Sasomers RT_ALL_FIBS); 243291993Smelifaro if (ia == NULL) 244291993Smelifaro goto bad; 245291993Smelifaro 246291993Smelifaro memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 247291993Smelifaro sizeof(struct in_addr)); 248291993Smelifaro ifa_free(&ia->ia_ifa); 249291993Smelifaro } else { 250291993Smelifaro /* XXX MRT 0 for routing */ 251291993Smelifaro if (fib4_lookup_nh_ext(M_GETFIB(m), 252291993Smelifaro ipaddr.sin_addr, 0, 0, &nh_ext) != 0) 253291993Smelifaro goto bad; 254291993Smelifaro 255291993Smelifaro memcpy(cp + off, &nh_ext.nh_src, 256291993Smelifaro sizeof(struct in_addr)); 257152592Sandre } 258291993Smelifaro 259152592Sandre ip->ip_dst = ipaddr.sin_addr; 260152592Sandre cp[IPOPT_OFFSET] += sizeof(struct in_addr); 261152592Sandre /* 262152592Sandre * Let ip_intr's mcast routing check handle mcast pkts 263152592Sandre */ 264152592Sandre forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 265152592Sandre break; 266152592Sandre 267152592Sandre case IPOPT_RR: 268152592Sandre#ifdef IPSTEALTH 269181803Sbz if (V_ipstealth && pass == 0) 270152592Sandre break; 271152592Sandre#endif 272152592Sandre if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 273152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 274152592Sandre goto bad; 275152592Sandre } 276152592Sandre if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 277152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 278152592Sandre goto bad; 279152592Sandre } 280152592Sandre /* 281152592Sandre * If no space remains, ignore. 282152592Sandre */ 283152592Sandre off--; /* 0 origin */ 284152592Sandre if (off > optlen - (int)sizeof(struct in_addr)) 285152592Sandre break; 286152592Sandre (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 287152592Sandre sizeof(ipaddr.sin_addr)); 288152592Sandre /* 289169464Srwatson * Locate outgoing interface; if we're the 290169464Srwatson * destination, use the incoming interface (should be 291169464Srwatson * same). 292152592Sandre */ 293292015Smelifaro if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) != NULL) { 294292015Smelifaro memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 295292015Smelifaro sizeof(struct in_addr)); 296292015Smelifaro ifa_free(&ia->ia_ifa); 297292015Smelifaro } else if (fib4_lookup_nh_ext(M_GETFIB(m), 298292015Smelifaro ipaddr.sin_addr, 0, 0, &nh_ext) == 0) { 299292015Smelifaro memcpy(cp + off, &nh_ext.nh_src, 300292015Smelifaro sizeof(struct in_addr)); 301292015Smelifaro } else { 302152592Sandre type = ICMP_UNREACH; 303152592Sandre code = ICMP_UNREACH_HOST; 304152592Sandre goto bad; 305152592Sandre } 306152592Sandre cp[IPOPT_OFFSET] += sizeof(struct in_addr); 307152592Sandre break; 308152592Sandre 309152592Sandre case IPOPT_TS: 310152592Sandre#ifdef IPSTEALTH 311181803Sbz if (V_ipstealth && pass == 0) 312152592Sandre break; 313152592Sandre#endif 314152592Sandre code = cp - (u_char *)ip; 315152592Sandre if (optlen < 4 || optlen > 40) { 316152592Sandre code = &cp[IPOPT_OLEN] - (u_char *)ip; 317152592Sandre goto bad; 318152592Sandre } 319152592Sandre if ((off = cp[IPOPT_OFFSET]) < 5) { 320152592Sandre code = &cp[IPOPT_OLEN] - (u_char *)ip; 321152592Sandre goto bad; 322152592Sandre } 323152592Sandre if (off > optlen - (int)sizeof(int32_t)) { 324152592Sandre cp[IPOPT_OFFSET + 1] += (1 << 4); 325152592Sandre if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 326152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 327152592Sandre goto bad; 328152592Sandre } 329152592Sandre break; 330152592Sandre } 331152592Sandre off--; /* 0 origin */ 332152592Sandre sin = (struct in_addr *)(cp + off); 333152592Sandre switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 334152592Sandre 335152592Sandre case IPOPT_TS_TSONLY: 336152592Sandre break; 337152592Sandre 338152592Sandre case IPOPT_TS_TSANDADDR: 339188578Sluigi if (off + sizeof(uint32_t) + 340152592Sandre sizeof(struct in_addr) > optlen) { 341152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 342152592Sandre goto bad; 343152592Sandre } 344152592Sandre ipaddr.sin_addr = dst; 345152592Sandre ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 346152592Sandre m->m_pkthdr.rcvif); 347152592Sandre if (ia == NULL) 348152592Sandre continue; 349152592Sandre (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 350152592Sandre sizeof(struct in_addr)); 351194760Srwatson ifa_free(&ia->ia_ifa); 352152592Sandre cp[IPOPT_OFFSET] += sizeof(struct in_addr); 353152592Sandre off += sizeof(struct in_addr); 354152592Sandre break; 355152592Sandre 356152592Sandre case IPOPT_TS_PRESPEC: 357188578Sluigi if (off + sizeof(uint32_t) + 358152592Sandre sizeof(struct in_addr) > optlen) { 359152592Sandre code = &cp[IPOPT_OFFSET] - (u_char *)ip; 360152592Sandre goto bad; 361152592Sandre } 362152592Sandre (void)memcpy(&ipaddr.sin_addr, sin, 363152592Sandre sizeof(struct in_addr)); 364213832Sbz if (ifa_ifwithaddr_check((SA)&ipaddr) == 0) 365152592Sandre continue; 366152592Sandre cp[IPOPT_OFFSET] += sizeof(struct in_addr); 367152592Sandre off += sizeof(struct in_addr); 368152592Sandre break; 369152592Sandre 370152592Sandre default: 371152592Sandre code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 372152592Sandre goto bad; 373152592Sandre } 374152592Sandre ntime = iptime(); 375188578Sluigi (void)memcpy(cp + off, &ntime, sizeof(uint32_t)); 376188578Sluigi cp[IPOPT_OFFSET] += sizeof(uint32_t); 377152592Sandre } 378152592Sandre } 379181803Sbz if (forward && V_ipforwarding) { 380152592Sandre ip_forward(m, 1); 381152592Sandre return (1); 382152592Sandre } 383152592Sandre return (0); 384152592Sandrebad: 385152592Sandre icmp_error(m, type, code, 0, 0); 386190951Srwatson IPSTAT_INC(ips_badoptions); 387152592Sandre return (1); 388152592Sandre} 389152592Sandre 390152592Sandre/* 391169464Srwatson * Save incoming source route for use in replies, to be picked up later by 392169464Srwatson * ip_srcroute if the receiver is interested. 393152592Sandre */ 394152592Sandrestatic void 395169454Srwatsonsave_rte(struct mbuf *m, u_char *option, struct in_addr dst) 396152592Sandre{ 397152592Sandre unsigned olen; 398152592Sandre struct ipopt_tag *opts; 399152592Sandre 400152592Sandre opts = (struct ipopt_tag *)m_tag_get(PACKET_TAG_IPOPTIONS, 401169464Srwatson sizeof(struct ipopt_tag), M_NOWAIT); 402152592Sandre if (opts == NULL) 403152592Sandre return; 404152592Sandre 405152592Sandre olen = option[IPOPT_OLEN]; 406152592Sandre if (olen > sizeof(opts->ip_srcrt) - (1 + sizeof(dst))) { 407152592Sandre m_tag_free((struct m_tag *)opts); 408152592Sandre return; 409152592Sandre } 410152592Sandre bcopy(option, opts->ip_srcrt.srcopt, olen); 411152592Sandre opts->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 412152592Sandre opts->ip_srcrt.dst = dst; 413152592Sandre m_tag_prepend(m, (struct m_tag *)opts); 414152592Sandre} 415152592Sandre 416152592Sandre/* 417169464Srwatson * Retrieve incoming source route for use in replies, in the same form used 418169464Srwatson * by setsockopt. The first hop is placed before the options, will be 419169464Srwatson * removed later. 420152592Sandre */ 421152592Sandrestruct mbuf * 422169454Srwatsonip_srcroute(struct mbuf *m0) 423152592Sandre{ 424169464Srwatson struct in_addr *p, *q; 425169464Srwatson struct mbuf *m; 426152592Sandre struct ipopt_tag *opts; 427152592Sandre 428152592Sandre opts = (struct ipopt_tag *)m_tag_find(m0, PACKET_TAG_IPOPTIONS, NULL); 429152592Sandre if (opts == NULL) 430152592Sandre return (NULL); 431152592Sandre 432152592Sandre if (opts->ip_nhops == 0) 433152592Sandre return (NULL); 434243882Sglebius m = m_get(M_NOWAIT, MT_DATA); 435152592Sandre if (m == NULL) 436152592Sandre return (NULL); 437152592Sandre 438152592Sandre#define OPTSIZ (sizeof(opts->ip_srcrt.nop) + sizeof(opts->ip_srcrt.srcopt)) 439152592Sandre 440152592Sandre /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 441152592Sandre m->m_len = opts->ip_nhops * sizeof(struct in_addr) + 442152592Sandre sizeof(struct in_addr) + OPTSIZ; 443152592Sandre 444152592Sandre /* 445169464Srwatson * First, save first hop for return route. 446152592Sandre */ 447152592Sandre p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]); 448152592Sandre *(mtod(m, struct in_addr *)) = *p--; 449152592Sandre 450152592Sandre /* 451152592Sandre * Copy option fields and padding (nop) to mbuf. 452152592Sandre */ 453152592Sandre opts->ip_srcrt.nop = IPOPT_NOP; 454152592Sandre opts->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 455152592Sandre (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 456152592Sandre &(opts->ip_srcrt.nop), OPTSIZ); 457152592Sandre q = (struct in_addr *)(mtod(m, caddr_t) + 458152592Sandre sizeof(struct in_addr) + OPTSIZ); 459152592Sandre#undef OPTSIZ 460152592Sandre /* 461169464Srwatson * Record return path as an IP source route, reversing the path 462169464Srwatson * (pointers are now aligned). 463152592Sandre */ 464152592Sandre while (p >= opts->ip_srcrt.route) { 465152592Sandre *q++ = *p--; 466152592Sandre } 467152592Sandre /* 468152592Sandre * Last hop goes to final destination. 469152592Sandre */ 470152592Sandre *q = opts->ip_srcrt.dst; 471152592Sandre m_tag_delete(m0, (struct m_tag *)opts); 472152592Sandre return (m); 473152592Sandre} 474152592Sandre 475152592Sandre/* 476241480Sglebius * Strip out IP options, at higher level protocol in the kernel. 477152592Sandre */ 478152592Sandrevoid 479241480Sglebiusip_stripoptions(struct mbuf *m) 480152592Sandre{ 481152592Sandre struct ip *ip = mtod(m, struct ip *); 482152592Sandre int olen; 483152592Sandre 484241925Sglebius olen = (ip->ip_hl << 2) - sizeof(struct ip); 485152592Sandre m->m_len -= olen; 486152592Sandre if (m->m_flags & M_PKTHDR) 487152592Sandre m->m_pkthdr.len -= olen; 488241923Sglebius ip->ip_len = htons(ntohs(ip->ip_len) - olen); 489152592Sandre ip->ip_hl = sizeof(struct ip) >> 2; 490241925Sglebius 491241925Sglebius bcopy((char *)ip + sizeof(struct ip) + olen, (ip + 1), 492241925Sglebius (size_t )(m->m_len - sizeof(struct ip))); 493152592Sandre} 494152592Sandre 495152592Sandre/* 496169464Srwatson * Insert IP options into preformed packet. Adjust IP destination as 497169464Srwatson * required for IP source routing, as indicated by a non-zero in_addr at the 498169464Srwatson * start of the options. 499152592Sandre * 500152592Sandre * XXX This routine assumes that the packet has no options in place. 501152592Sandre */ 502152592Sandrestruct mbuf * 503169454Srwatsonip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen) 504152592Sandre{ 505169464Srwatson struct ipoption *p = mtod(opt, struct ipoption *); 506152592Sandre struct mbuf *n; 507169464Srwatson struct ip *ip = mtod(m, struct ip *); 508152592Sandre unsigned optlen; 509152592Sandre 510152592Sandre optlen = opt->m_len - sizeof(p->ipopt_dst); 511241913Sglebius if (optlen + ntohs(ip->ip_len) > IP_MAXPACKET) { 512152592Sandre *phlen = 0; 513152592Sandre return (m); /* XXX should fail */ 514152592Sandre } 515152592Sandre if (p->ipopt_dst.s_addr) 516152592Sandre ip->ip_dst = p->ipopt_dst; 517276752Srwatson if (!M_WRITABLE(m) || M_LEADINGSPACE(m) < optlen) { 518248324Sglebius n = m_gethdr(M_NOWAIT, MT_DATA); 519152592Sandre if (n == NULL) { 520152592Sandre *phlen = 0; 521152592Sandre return (m); 522152592Sandre } 523248373Sglebius m_move_pkthdr(n, m); 524152592Sandre n->m_pkthdr.rcvif = NULL; 525152592Sandre n->m_pkthdr.len += optlen; 526152592Sandre m->m_len -= sizeof(struct ip); 527152592Sandre m->m_data += sizeof(struct ip); 528152592Sandre n->m_next = m; 529152592Sandre m = n; 530152592Sandre m->m_len = optlen + sizeof(struct ip); 531152592Sandre m->m_data += max_linkhdr; 532152592Sandre bcopy(ip, mtod(m, void *), sizeof(struct ip)); 533152592Sandre } else { 534152592Sandre m->m_data -= optlen; 535152592Sandre m->m_len += optlen; 536152592Sandre m->m_pkthdr.len += optlen; 537152592Sandre bcopy(ip, mtod(m, void *), sizeof(struct ip)); 538152592Sandre } 539152592Sandre ip = mtod(m, struct ip *); 540152592Sandre bcopy(p->ipopt_list, ip + 1, optlen); 541152592Sandre *phlen = sizeof(struct ip) + optlen; 542152592Sandre ip->ip_v = IPVERSION; 543152592Sandre ip->ip_hl = *phlen >> 2; 544241913Sglebius ip->ip_len = htons(ntohs(ip->ip_len) + optlen); 545152592Sandre return (m); 546152592Sandre} 547152592Sandre 548152592Sandre/* 549169464Srwatson * Copy options from ip to jp, omitting those not copied during 550169464Srwatson * fragmentation. 551152592Sandre */ 552152592Sandreint 553169454Srwatsonip_optcopy(struct ip *ip, struct ip *jp) 554152592Sandre{ 555169464Srwatson u_char *cp, *dp; 556152592Sandre int opt, optlen, cnt; 557152592Sandre 558152592Sandre cp = (u_char *)(ip + 1); 559152592Sandre dp = (u_char *)(jp + 1); 560152592Sandre cnt = (ip->ip_hl << 2) - sizeof (struct ip); 561152592Sandre for (; cnt > 0; cnt -= optlen, cp += optlen) { 562152592Sandre opt = cp[0]; 563152592Sandre if (opt == IPOPT_EOL) 564152592Sandre break; 565152592Sandre if (opt == IPOPT_NOP) { 566152592Sandre /* Preserve for IP mcast tunnel's LSRR alignment. */ 567152592Sandre *dp++ = IPOPT_NOP; 568152592Sandre optlen = 1; 569152592Sandre continue; 570152592Sandre } 571152592Sandre 572152592Sandre KASSERT(cnt >= IPOPT_OLEN + sizeof(*cp), 573152592Sandre ("ip_optcopy: malformed ipv4 option")); 574152592Sandre optlen = cp[IPOPT_OLEN]; 575152592Sandre KASSERT(optlen >= IPOPT_OLEN + sizeof(*cp) && optlen <= cnt, 576152592Sandre ("ip_optcopy: malformed ipv4 option")); 577152592Sandre 578169464Srwatson /* Bogus lengths should have been caught by ip_dooptions. */ 579152592Sandre if (optlen > cnt) 580152592Sandre optlen = cnt; 581152592Sandre if (IPOPT_COPIED(opt)) { 582152592Sandre bcopy(cp, dp, optlen); 583152592Sandre dp += optlen; 584152592Sandre } 585152592Sandre } 586152592Sandre for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 587152592Sandre *dp++ = IPOPT_EOL; 588152592Sandre return (optlen); 589152592Sandre} 590152592Sandre 591152592Sandre/* 592169464Srwatson * Set up IP options in pcb for insertion in output packets. Store in mbuf 593169464Srwatson * with pointer in pcbopt, adding pseudo-option with destination address if 594169464Srwatson * source routed. 595152592Sandre */ 596152592Sandreint 597152592Sandreip_pcbopts(struct inpcb *inp, int optname, struct mbuf *m) 598152592Sandre{ 599169464Srwatson int cnt, optlen; 600169464Srwatson u_char *cp; 601152592Sandre struct mbuf **pcbopt; 602152592Sandre u_char opt; 603152592Sandre 604178285Srwatson INP_WLOCK_ASSERT(inp); 605152592Sandre 606152592Sandre pcbopt = &inp->inp_options; 607152592Sandre 608152592Sandre /* turn off any old options */ 609152592Sandre if (*pcbopt) 610152592Sandre (void)m_free(*pcbopt); 611298066Spfg *pcbopt = NULL; 612152592Sandre if (m == NULL || m->m_len == 0) { 613152592Sandre /* 614152592Sandre * Only turning off any previous options. 615152592Sandre */ 616152592Sandre if (m != NULL) 617152592Sandre (void)m_free(m); 618152592Sandre return (0); 619152592Sandre } 620152592Sandre 621152592Sandre if (m->m_len % sizeof(int32_t)) 622152592Sandre goto bad; 623152592Sandre /* 624169464Srwatson * IP first-hop destination address will be stored before actual 625169464Srwatson * options; move other options back and clear it when none present. 626152592Sandre */ 627152592Sandre if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN]) 628152592Sandre goto bad; 629152592Sandre cnt = m->m_len; 630152592Sandre m->m_len += sizeof(struct in_addr); 631152592Sandre cp = mtod(m, u_char *) + sizeof(struct in_addr); 632152592Sandre bcopy(mtod(m, void *), cp, (unsigned)cnt); 633152592Sandre bzero(mtod(m, void *), sizeof(struct in_addr)); 634152592Sandre 635152592Sandre for (; cnt > 0; cnt -= optlen, cp += optlen) { 636152592Sandre opt = cp[IPOPT_OPTVAL]; 637152592Sandre if (opt == IPOPT_EOL) 638152592Sandre break; 639152592Sandre if (opt == IPOPT_NOP) 640152592Sandre optlen = 1; 641152592Sandre else { 642152592Sandre if (cnt < IPOPT_OLEN + sizeof(*cp)) 643152592Sandre goto bad; 644152592Sandre optlen = cp[IPOPT_OLEN]; 645152592Sandre if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) 646152592Sandre goto bad; 647152592Sandre } 648152592Sandre switch (opt) { 649152592Sandre 650152592Sandre default: 651152592Sandre break; 652152592Sandre 653152592Sandre case IPOPT_LSRR: 654152592Sandre case IPOPT_SSRR: 655152592Sandre /* 656169464Srwatson * User process specifies route as: 657169464Srwatson * 658152592Sandre * ->A->B->C->D 659169464Srwatson * 660152592Sandre * D must be our final destination (but we can't 661152592Sandre * check that since we may not have connected yet). 662169464Srwatson * A is first hop destination, which doesn't appear 663169464Srwatson * in actual IP option, but is stored before the 664169464Srwatson * options. 665152592Sandre */ 666175630Sbz /* XXX-BZ PRIV_NETINET_SETHDROPTS? */ 667152592Sandre if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr)) 668152592Sandre goto bad; 669152592Sandre m->m_len -= sizeof(struct in_addr); 670152592Sandre cnt -= sizeof(struct in_addr); 671152592Sandre optlen -= sizeof(struct in_addr); 672152592Sandre cp[IPOPT_OLEN] = optlen; 673152592Sandre /* 674152592Sandre * Move first hop before start of options. 675152592Sandre */ 676152592Sandre bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t), 677152592Sandre sizeof(struct in_addr)); 678152592Sandre /* 679152592Sandre * Then copy rest of options back 680152592Sandre * to close up the deleted entry. 681152592Sandre */ 682152592Sandre bcopy((&cp[IPOPT_OFFSET+1] + sizeof(struct in_addr)), 683152592Sandre &cp[IPOPT_OFFSET+1], 684152592Sandre (unsigned)cnt - (IPOPT_MINOFF - 1)); 685152592Sandre break; 686152592Sandre } 687152592Sandre } 688152592Sandre if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr)) 689152592Sandre goto bad; 690152592Sandre *pcbopt = m; 691152592Sandre return (0); 692152592Sandre 693152592Sandrebad: 694152592Sandre (void)m_free(m); 695152592Sandre return (EINVAL); 696152592Sandre} 697189343Sbms 698189343Sbms/* 699189343Sbms * Check for the presence of the IP Router Alert option [RFC2113] 700189343Sbms * in the header of an IPv4 datagram. 701189343Sbms * 702189343Sbms * This call is not intended for use from the forwarding path; it is here 703189343Sbms * so that protocol domains may check for the presence of the option. 704189343Sbms * Given how FreeBSD's IPv4 stack is currently structured, the Router Alert 705189343Sbms * option does not have much relevance to the implementation, though this 706189343Sbms * may change in future. 707189343Sbms * Router alert options SHOULD be passed if running in IPSTEALTH mode and 708189343Sbms * we are not the endpoint. 709298995Spfg * Length checks on individual options should already have been performed 710189343Sbms * by ip_dooptions() therefore they are folded under INVARIANTS here. 711189343Sbms * 712189343Sbms * Return zero if not present or options are invalid, non-zero if present. 713189343Sbms */ 714189343Sbmsint 715189343Sbmsip_checkrouteralert(struct mbuf *m) 716189343Sbms{ 717189343Sbms struct ip *ip = mtod(m, struct ip *); 718189343Sbms u_char *cp; 719189343Sbms int opt, optlen, cnt, found_ra; 720189343Sbms 721189343Sbms found_ra = 0; 722189343Sbms cp = (u_char *)(ip + 1); 723189343Sbms cnt = (ip->ip_hl << 2) - sizeof (struct ip); 724189343Sbms for (; cnt > 0; cnt -= optlen, cp += optlen) { 725189343Sbms opt = cp[IPOPT_OPTVAL]; 726189343Sbms if (opt == IPOPT_EOL) 727189343Sbms break; 728189343Sbms if (opt == IPOPT_NOP) 729189343Sbms optlen = 1; 730189343Sbms else { 731189343Sbms#ifdef INVARIANTS 732189343Sbms if (cnt < IPOPT_OLEN + sizeof(*cp)) 733189343Sbms break; 734189343Sbms#endif 735189343Sbms optlen = cp[IPOPT_OLEN]; 736189343Sbms#ifdef INVARIANTS 737189343Sbms if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) 738189343Sbms break; 739189343Sbms#endif 740189343Sbms } 741189343Sbms switch (opt) { 742189343Sbms case IPOPT_RA: 743189343Sbms#ifdef INVARIANTS 744189343Sbms if (optlen != IPOPT_OFFSET + sizeof(uint16_t) || 745189343Sbms (*((uint16_t *)&cp[IPOPT_OFFSET]) != 0)) 746189343Sbms break; 747189343Sbms else 748189343Sbms#endif 749189343Sbms found_ra = 1; 750189343Sbms break; 751189343Sbms default: 752189343Sbms break; 753189343Sbms } 754189343Sbms } 755189343Sbms 756189343Sbms return (found_ra); 757189343Sbms} 758