2  * SPDX-License-Identifier: BSD-3-Clause
73     "Enable forwarding source routed IP packets");
79     "Enable accepting source routed IP packets");
90  * are encountered, or forwarding it if source-routed.
94  * reason for as many as two passes is that when doing IPSTEALTH, non-routing
123 	dst = ip->ip_dst;  in ip_dooptions()
125 	cnt = (ip->ip_hl << 2) - sizeof (struct ip);  in ip_dooptions()
126 	for (; cnt > 0; cnt -= optlen, cp += optlen) {  in ip_dooptions()
134 				code = &cp[IPOPT_OLEN] - (u_char *)ip;  in ip_dooptions()
139 				code = &cp[IPOPT_OLEN] - (u_char *)ip;  in ip_dooptions()
150 		 * strictly routed, or do nothing if loosely routed.  Record  in ip_dooptions()
152 		 * strictly routed make sure next address is on directly  in ip_dooptions()
162 				code = &cp[IPOPT_OLEN] - (u_char *)ip;  in ip_dooptions()
166 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;  in ip_dooptions()
169 			ipaddr.sin_addr = ip->ip_dst;  in ip_dooptions()
185 			off--;			/* 0 origin */  in ip_dooptions()
186 			if (off > optlen - (int)sizeof(struct in_addr)) {  in ip_dooptions()
192 				save_rte(m, cp, ip->ip_src);  in ip_dooptions()
212 					    inet_ntoa_r(ip->ip_src, srcbuf),  in ip_dooptions()
213 					    inet_ntoa_r(ip->ip_dst, dstbuf));  in ip_dooptions()
251 				memcpy(cp + off, &(IA_SIN(ia)->sin_addr),  in ip_dooptions()
260 				memcpy(cp + off, &(IA_SIN(nh->nh_ifa)->sin_addr),  in ip_dooptions()
264 			ip->ip_dst = ipaddr.sin_addr;  in ip_dooptions()
269 			forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));  in ip_dooptions()
278 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;  in ip_dooptions()
282 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;  in ip_dooptions()
288 			off--;			/* 0 origin */  in ip_dooptions()
289 			if (off > optlen - (int)sizeof(struct in_addr))  in ip_dooptions()
291 			(void)memcpy(&ipaddr.sin_addr, &ip->ip_dst,  in ip_dooptions()
294 			 * Locate outgoing interface; if we're the  in ip_dooptions()
299 				memcpy(cp + off, &(IA_SIN(ia)->sin_addr),  in ip_dooptions()
303 				memcpy(cp + off, &(IA_SIN(nh->nh_ifa)->sin_addr),  in ip_dooptions()
318 			code = cp - (u_char *)ip;  in ip_dooptions()
320 				code = &cp[IPOPT_OLEN] - (u_char *)ip;  in ip_dooptions()
324 				code = &cp[IPOPT_OLEN] - (u_char *)ip;  in ip_dooptions()
327 			if (off > optlen - (int)sizeof(int32_t)) {  in ip_dooptions()
330 					code = &cp[IPOPT_OFFSET] - (u_char *)ip;  in ip_dooptions()
335 			off--;				/* 0 origin */  in ip_dooptions()
344 					code = &cp[IPOPT_OFFSET] - (u_char *)ip;  in ip_dooptions()
349 							    m->m_pkthdr.rcvif);  in ip_dooptions()
352 				(void)memcpy(sin, &IA_SIN(ia)->sin_addr,  in ip_dooptions()
361 					code = &cp[IPOPT_OFFSET] - (u_char *)ip;  in ip_dooptions()
373 				code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip;  in ip_dooptions()
408 	if (olen > sizeof(opts->ip_srcrt) - (1 + sizeof(dst))) {  in save_rte()
412 	bcopy(option, opts->ip_srcrt.srcopt, olen);  in save_rte()
413 	opts->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);  in save_rte()
414 	opts->ip_srcrt.dst = dst;  in save_rte()
434 	if (opts->ip_nhops == 0)  in ip_srcroute()
440 #define OPTSIZ	(sizeof(opts->ip_srcrt.nop) + sizeof(opts->ip_srcrt.srcopt))  in ip_srcroute()
443 	m->m_len = opts->ip_nhops * sizeof(struct in_addr) +  in ip_srcroute()
449 	p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]);  in ip_srcroute()
450 	*(mtod(m, struct in_addr *)) = *p--;  in ip_srcroute()
455 	opts->ip_srcrt.nop = IPOPT_NOP;  in ip_srcroute()
456 	opts->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;  in ip_srcroute()
458 	    &(opts->ip_srcrt.nop), OPTSIZ);  in ip_srcroute()
466 	while (p >= opts->ip_srcrt.route) {  in ip_srcroute()
467 		*q++ = *p--;  in ip_srcroute()
472 	*q = opts->ip_srcrt.dst;  in ip_srcroute()
486 	olen = (ip->ip_hl << 2) - sizeof(struct ip);  in ip_stripoptions()
487 	m->m_len -= olen;  in ip_stripoptions()
488 	if (m->m_flags & M_PKTHDR)  in ip_stripoptions()
489 		m->m_pkthdr.len -= olen;  in ip_stripoptions()
490 	ip->ip_len = htons(ntohs(ip->ip_len) - olen);  in ip_stripoptions()
491 	ip->ip_hl = sizeof(struct ip) >> 2;  in ip_stripoptions()
494 	    (size_t )(m->m_len - sizeof(struct ip)));  in ip_stripoptions()
499  * required for IP source routing, as indicated by a non-zero in_addr at the
512 	optlen = opt->m_len - sizeof(p->ipopt_dst);  in ip_insertoptions()
513 	if (optlen + ntohs(ip->ip_len) > IP_MAXPACKET) {  in ip_insertoptions()
517 	KASSERT((m->m_flags & M_EXTPG) == 0, ("%s: mbuf %p is unmapped",  in ip_insertoptions()
519 	if (p->ipopt_dst.s_addr)  in ip_insertoptions()
520 		ip->ip_dst = p->ipopt_dst;  in ip_insertoptions()
528 		n->m_pkthdr.rcvif = NULL;  in ip_insertoptions()
529 		n->m_pkthdr.len += optlen;  in ip_insertoptions()
530 		m->m_len -= sizeof(struct ip);  in ip_insertoptions()
531 		m->m_data += sizeof(struct ip);  in ip_insertoptions()
532 		n->m_next = m;  in ip_insertoptions()
534 		m->m_len = optlen + sizeof(struct ip);  in ip_insertoptions()
535 		m->m_data += max_linkhdr;  in ip_insertoptions()
538 		m->m_data -= optlen;  in ip_insertoptions()
539 		m->m_len += optlen;  in ip_insertoptions()
540 		m->m_pkthdr.len += optlen;  in ip_insertoptions()
544 	bcopy(p->ipopt_list, ip + 1, optlen);  in ip_insertoptions()
546 	ip->ip_v = IPVERSION;  in ip_insertoptions()
547 	ip->ip_hl = *phlen >> 2;  in ip_insertoptions()
548 	ip->ip_len = htons(ntohs(ip->ip_len) + optlen);  in ip_insertoptions()
564 	cnt = (ip->ip_hl << 2) - sizeof (struct ip);  in ip_optcopy()
565 	for (; cnt > 0; cnt -= optlen, cp += optlen) {  in ip_optcopy()
590 	for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)  in ip_optcopy()
597  * with pointer in pcbopt, adding pseudo-option with destination address if
598  * source routed.
610 	pcbopt = &inp->inp_options;  in ip_pcbopts()
616 	if (m == NULL || m->m_len == 0) {  in ip_pcbopts()
625 	if (m->m_len % sizeof(int32_t))  in ip_pcbopts()
628 	 * IP first-hop destination address will be stored before actual  in ip_pcbopts()
631 	if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN])  in ip_pcbopts()
633 	cnt = m->m_len;  in ip_pcbopts()
634 	m->m_len += sizeof(struct in_addr);  in ip_pcbopts()
639 	for (; cnt > 0; cnt -= optlen, cp += optlen) {  in ip_pcbopts()
661 			 *	->A->B->C->D  in ip_pcbopts()
669 			/* XXX-BZ PRIV_NETINET_SETHDROPTS? */  in ip_pcbopts()
670 			if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))  in ip_pcbopts()
672 			m->m_len -= sizeof(struct in_addr);  in ip_pcbopts()
673 			cnt -= sizeof(struct in_addr);  in ip_pcbopts()
674 			optlen -= sizeof(struct in_addr);  in ip_pcbopts()
687 			    (unsigned)cnt - (IPOPT_MINOFF - 1));  in ip_pcbopts()
691 	if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr))  in ip_pcbopts()
715  * Return zero if not present or options are invalid, non-zero if present.
726 	cnt = (ip->ip_hl << 2) - sizeof (struct ip);  in ip_checkrouteralert()
727 	for (; cnt > 0; cnt -= optlen, cp += optlen) {  in ip_checkrouteralert()