// See the file "COPYING" in the main distribution directory for copyright.

#include "zeek/IP.h"

#include <netinet/icmp6.h>
#include <netinet/in.h>
#include <sys/types.h>

#include "zeek/IPAddr.h"
#include "zeek/Reporter.h"
#include "zeek/Type.h"
#include "zeek/Val.h"
#include "zeek/Var.h"
#include "zeek/ZeekString.h"

namespace zeek
	{

static VectorValPtr BuildOptionsVal(const u_char* data, int len)
	{
	auto vv = make_intrusive<VectorVal>(id::find_type<VectorType>("ip6_options"));

	while ( static_cast<size_t>(len) >= sizeof(struct ip6_opt) )
		{
		static auto ip6_option_type = id::find_type<RecordType>("ip6_option");
		const struct ip6_opt* opt = (const struct ip6_opt*)data;
		auto rv = make_intrusive<RecordVal>(ip6_option_type);
		rv->Assign(0, opt->ip6o_type);

		if ( opt->ip6o_type == 0 )
			{
			// Pad1 option
			rv->Assign(1, 0);
			rv->Assign(2, val_mgr->EmptyString());
			data += sizeof(uint8_t);
			len -= sizeof(uint8_t);
			}
		else
			{
			// PadN or other option
			uint16_t off = 2 * sizeof(uint8_t);

			if ( len < opt->ip6o_len + off )
				break;

			rv->Assign(1, opt->ip6o_len);
			rv->Assign(2, new String(data + off, opt->ip6o_len, true));
			data += opt->ip6o_len + off;
			len -= opt->ip6o_len + off;
			}

		vv->Assign(vv->Size(), std::move(rv));
		}

	return vv;
	}

RecordValPtr IPv6_Hdr::ToVal(VectorValPtr chain) const
	{
	RecordValPtr rv;

	switch ( type )
		{
		case IPPROTO_IPV6:
			{
			static auto ip6_hdr_type = id::find_type<RecordType>("ip6_hdr");
			rv = make_intrusive<RecordVal>(ip6_hdr_type);
			const struct ip6_hdr* ip6 = (const struct ip6_hdr*)data;
			rv->Assign(0, static_cast<uint32_t>(ntohl(ip6->ip6_flow) & 0x0ff00000) >> 20);
			rv->Assign(1, static_cast<uint32_t>(ntohl(ip6->ip6_flow) & 0x000fffff));
			rv->Assign(2, ntohs(ip6->ip6_plen));
			rv->Assign(3, ip6->ip6_nxt);
			rv->Assign(4, ip6->ip6_hlim);
			rv->Assign(5, make_intrusive<AddrVal>(IPAddr(ip6->ip6_src)));
			rv->Assign(6, make_intrusive<AddrVal>(IPAddr(ip6->ip6_dst)));
			if ( ! chain )
				chain = make_intrusive<VectorVal>(id::find_type<VectorType>("ip6_ext_hdr_chain"));
			rv->Assign(7, std::move(chain));
			}
			break;

		case IPPROTO_HOPOPTS:
			{
			static auto ip6_hopopts_type = id::find_type<RecordType>("ip6_hopopts");
			rv = make_intrusive<RecordVal>(ip6_hopopts_type);
			const struct ip6_hbh* hbh = (const struct ip6_hbh*)data;
			rv->Assign(0, hbh->ip6h_nxt);
			rv->Assign(1, hbh->ip6h_len);
			uint16_t off = 2 * sizeof(uint8_t);
			rv->Assign(2, BuildOptionsVal(data + off, Length() - off));
			}
			break;

		case IPPROTO_DSTOPTS:
			{
			static auto ip6_dstopts_type = id::find_type<RecordType>("ip6_dstopts");
			rv = make_intrusive<RecordVal>(ip6_dstopts_type);
			const struct ip6_dest* dst = (const struct ip6_dest*)data;
			rv->Assign(0, dst->ip6d_nxt);
			rv->Assign(1, dst->ip6d_len);
			uint16_t off = 2 * sizeof(uint8_t);
			rv->Assign(2, BuildOptionsVal(data + off, Length() - off));
			}
			break;

		case IPPROTO_ROUTING:
			{
			static auto ip6_routing_type = id::find_type<RecordType>("ip6_routing");
			rv = make_intrusive<RecordVal>(ip6_routing_type);
			const struct ip6_rthdr* rt = (const struct ip6_rthdr*)data;
			rv->Assign(0, rt->ip6r_nxt);
			rv->Assign(1, rt->ip6r_len);
			rv->Assign(2, rt->ip6r_type);
			rv->Assign(3, rt->ip6r_segleft);
			uint16_t off = 4 * sizeof(uint8_t);
			rv->Assign(4, new String(data + off, Length() - off, true));
			}
			break;

		case IPPROTO_FRAGMENT:
			{
			static auto ip6_fragment_type = id::find_type<RecordType>("ip6_fragment");
			rv = make_intrusive<RecordVal>(ip6_fragment_type);
			const struct ip6_frag* frag = (const struct ip6_frag*)data;
			rv->Assign(0, frag->ip6f_nxt);
			rv->Assign(1, frag->ip6f_reserved);
			rv->Assign(2, (ntohs(frag->ip6f_offlg) & 0xfff8) >> 3);
			rv->Assign(3, (ntohs(frag->ip6f_offlg) & 0x0006) >> 1);
			rv->Assign(4, static_cast<bool>(ntohs(frag->ip6f_offlg) & 0x0001));
			rv->Assign(5, static_cast<uint32_t>(ntohl(frag->ip6f_ident)));
			}
			break;

		case IPPROTO_AH:
			{
			static auto ip6_ah_type = id::find_type<RecordType>("ip6_ah");
			rv = make_intrusive<RecordVal>(ip6_ah_type);
			rv->Assign(0, ((ip6_ext*)data)->ip6e_nxt);
			rv->Assign(1, ((ip6_ext*)data)->ip6e_len);
			rv->Assign(2, ntohs(((uint16_t*)data)[1]));
			rv->Assign(3, static_cast<uint32_t>(ntohl(((uint32_t*)data)[1])));

			if ( Length() >= 12 )
				{
				// Sequence Number and ICV fields can only be extracted if
				// Payload Len was non-zero for this header.
				rv->Assign(4, static_cast<uint32_t>(ntohl(((uint32_t*)data)[2])));
				uint16_t off = 3 * sizeof(uint32_t);
				rv->Assign(5, new String(data + off, Length() - off, true));
				}
			}
			break;

		case IPPROTO_ESP:
			{
			static auto ip6_esp_type = id::find_type<RecordType>("ip6_esp");
			rv = make_intrusive<RecordVal>(ip6_esp_type);
			const uint32_t* esp = (const uint32_t*)data;
			rv->Assign(0, static_cast<uint32_t>(ntohl(esp[0])));
			rv->Assign(1, static_cast<uint32_t>(ntohl(esp[1])));
			}
			break;

		case IPPROTO_MOBILITY:
			{
			static auto ip6_mob_type = id::find_type<RecordType>("ip6_mobility_hdr");
			rv = make_intrusive<RecordVal>(ip6_mob_type);
			const struct ip6_mobility* mob = (const struct ip6_mobility*)data;
			rv->Assign(0, mob->ip6mob_payload);
			rv->Assign(1, mob->ip6mob_len);
			rv->Assign(2, mob->ip6mob_type);
			rv->Assign(3, mob->ip6mob_rsv);
			rv->Assign(4, ntohs(mob->ip6mob_chksum));

			static auto ip6_mob_msg_type = id::find_type<RecordType>("ip6_mobility_msg");
			auto msg = make_intrusive<RecordVal>(ip6_mob_msg_type);
			msg->Assign(0, mob->ip6mob_type);

			uint16_t off = sizeof(ip6_mobility);
			const u_char* msg_data = data + off;

			static auto ip6_mob_brr_type = id::find_type<RecordType>("ip6_mobility_brr");
			static auto ip6_mob_hoti_type = id::find_type<RecordType>("ip6_mobility_hoti");
			static auto ip6_mob_coti_type = id::find_type<RecordType>("ip6_mobility_coti");
			static auto ip6_mob_hot_type = id::find_type<RecordType>("ip6_mobility_hot");
			static auto ip6_mob_cot_type = id::find_type<RecordType>("ip6_mobility_cot");
			static auto ip6_mob_bu_type = id::find_type<RecordType>("ip6_mobility_bu");
			static auto ip6_mob_back_type = id::find_type<RecordType>("ip6_mobility_back");
			static auto ip6_mob_be_type = id::find_type<RecordType>("ip6_mobility_be");

			switch ( mob->ip6mob_type )
				{
				case 0:
					{
					auto m = make_intrusive<RecordVal>(ip6_mob_brr_type);
					m->Assign(0, ntohs(*((uint16_t*)msg_data)));
					off += sizeof(uint16_t);
					m->Assign(1, BuildOptionsVal(data + off, Length() - off));
					msg->Assign(1, std::move(m));
					}
					break;

				case 1:
					{
					auto m = make_intrusive<RecordVal>(ip6_mob_hoti_type);
					m->Assign(0, ntohs(*((uint16_t*)msg_data)));
					m->Assign(1, ntohll(*((uint64_t*)(msg_data + sizeof(uint16_t)))));
					off += sizeof(uint16_t) + sizeof(uint64_t);
					m->Assign(2, BuildOptionsVal(data + off, Length() - off));
					msg->Assign(2, std::move(m));
					break;
					}

				case 2:
					{
					auto m = make_intrusive<RecordVal>(ip6_mob_coti_type);
					m->Assign(0, ntohs(*((uint16_t*)msg_data)));
					m->Assign(1, ntohll(*((uint64_t*)(msg_data + sizeof(uint16_t)))));
					off += sizeof(uint16_t) + sizeof(uint64_t);
					m->Assign(2, BuildOptionsVal(data + off, Length() - off));
					msg->Assign(3, std::move(m));
					break;
					}

				case 3:
					{
					auto m = make_intrusive<RecordVal>(ip6_mob_hot_type);
					m->Assign(0, ntohs(*((uint16_t*)msg_data)));
					m->Assign(1, ntohll(*((uint64_t*)(msg_data + sizeof(uint16_t)))));
					m->Assign(
						2, ntohll(*((uint64_t*)(msg_data + sizeof(uint16_t) + sizeof(uint64_t)))));
					off += sizeof(uint16_t) + 2 * sizeof(uint64_t);
					m->Assign(3, BuildOptionsVal(data + off, Length() - off));
					msg->Assign(4, std::move(m));
					break;
					}

				case 4:
					{
					auto m = make_intrusive<RecordVal>(ip6_mob_cot_type);
					m->Assign(0, ntohs(*((uint16_t*)msg_data)));
					m->Assign(1, ntohll(*((uint64_t*)(msg_data + sizeof(uint16_t)))));
					m->Assign(
						2, ntohll(*((uint64_t*)(msg_data + sizeof(uint16_t) + sizeof(uint64_t)))));
					off += sizeof(uint16_t) + 2 * sizeof(uint64_t);
					m->Assign(3, BuildOptionsVal(data + off, Length() - off));
					msg->Assign(5, std::move(m));
					break;
					}

				case 5:
					{
					auto m = make_intrusive<RecordVal>(ip6_mob_bu_type);
					m->Assign(0, ntohs(*((uint16_t*)msg_data)));
					m->Assign(1, static_cast<bool>(
									 ntohs(*((uint16_t*)(msg_data + sizeof(uint16_t)))) & 0x8000));
					m->Assign(2, static_cast<bool>(
									 ntohs(*((uint16_t*)(msg_data + sizeof(uint16_t)))) & 0x4000));
					m->Assign(3, static_cast<bool>(
									 ntohs(*((uint16_t*)(msg_data + sizeof(uint16_t)))) & 0x2000));
					m->Assign(4, static_cast<bool>(
									 ntohs(*((uint16_t*)(msg_data + sizeof(uint16_t)))) & 0x1000));
					m->Assign(5, ntohs(*((uint16_t*)(msg_data + 2 * sizeof(uint16_t)))));
					off += 3 * sizeof(uint16_t);
					m->Assign(6, BuildOptionsVal(data + off, Length() - off));
					msg->Assign(6, std::move(m));
					break;
					}

				case 6:
					{
					auto m = make_intrusive<RecordVal>(ip6_mob_back_type);
					m->Assign(0, *((uint8_t*)msg_data));
					m->Assign(1,
					          static_cast<bool>(*((uint8_t*)(msg_data + sizeof(uint8_t))) & 0x80));
					m->Assign(2, ntohs(*((uint16_t*)(msg_data + sizeof(uint16_t)))));
					m->Assign(3, ntohs(*((uint16_t*)(msg_data + 2 * sizeof(uint16_t)))));
					off += 3 * sizeof(uint16_t);
					m->Assign(4, BuildOptionsVal(data + off, Length() - off));
					msg->Assign(7, std::move(m));
					break;
					}

				case 7:
					{
					auto m = make_intrusive<RecordVal>(ip6_mob_be_type);
					m->Assign(0, *((uint8_t*)msg_data));
					const in6_addr* hoa = (const in6_addr*)(msg_data + sizeof(uint16_t));
					m->Assign(1, make_intrusive<AddrVal>(IPAddr(*hoa)));
					off += sizeof(uint16_t) + sizeof(in6_addr);
					m->Assign(2, BuildOptionsVal(data + off, Length() - off));
					msg->Assign(8, std::move(m));
					break;
					}

				default:
					reporter->Weird("unknown_mobility_type", util::fmt("%d", mob->ip6mob_type));
					break;
				}

			rv->Assign(5, std::move(msg));
			}
			break;

		default:
			break;
		}

	return rv;
	}

RecordValPtr IPv6_Hdr::ToVal() const
	{
	return ToVal(nullptr);
	}

IPAddr IP_Hdr::IPHeaderSrcAddr() const
	{
	return ip4 ? IPAddr(ip4->ip_src) : IPAddr(ip6->ip6_src);
	}

IPAddr IP_Hdr::IPHeaderDstAddr() const
	{
	return ip4 ? IPAddr(ip4->ip_dst) : IPAddr(ip6->ip6_dst);
	}

IPAddr IP_Hdr::SrcAddr() const
	{
	return ip4 ? IPAddr(ip4->ip_src) : ip6_hdrs->SrcAddr();
	}

IPAddr IP_Hdr::DstAddr() const
	{
	return ip4 ? IPAddr(ip4->ip_dst) : ip6_hdrs->DstAddr();
	}

RecordValPtr IP_Hdr::ToIPHdrVal() const
	{
	RecordValPtr rval;

	if ( ip4 )
		{
		static auto ip4_hdr_type = id::find_type<RecordType>("ip4_hdr");
		rval = make_intrusive<RecordVal>(ip4_hdr_type);
		rval->Assign(0, ip4->ip_hl * 4);
		rval->Assign(1, ip4->ip_tos);
		rval->Assign(2, ntohs(ip4->ip_len));
		rval->Assign(3, ntohs(ip4->ip_id));
		rval->Assign(4, ip4->ip_ttl);
		rval->Assign(5, ip4->ip_p);
		rval->Assign(6, make_intrusive<AddrVal>(ip4->ip_src.s_addr));
		rval->Assign(7, make_intrusive<AddrVal>(ip4->ip_dst.s_addr));
		}
	else
		{
		rval = ((*ip6_hdrs)[0])->ToVal(ip6_hdrs->ToVal());
		}

	return rval;
	}

RecordValPtr IP_Hdr::ToPktHdrVal() const
	{
	static auto pkt_hdr_type = id::find_type<RecordType>("pkt_hdr");
	return ToPktHdrVal(make_intrusive<RecordVal>(pkt_hdr_type), 0);
	}

RecordValPtr IP_Hdr::ToPktHdrVal(RecordValPtr pkt_hdr, int sindex) const
	{
	static auto tcp_hdr_type = id::find_type<RecordType>("tcp_hdr");
	static auto udp_hdr_type = id::find_type<RecordType>("udp_hdr");
	static auto icmp_hdr_type = id::find_type<RecordType>("icmp_hdr");

	if ( ip4 )
		pkt_hdr->Assign(sindex + 0, ToIPHdrVal());
	else
		pkt_hdr->Assign(sindex + 1, ToIPHdrVal());

	// L4 header.
	const u_char* data = Payload();

	int proto = NextProto();
	switch ( proto )
		{
		case IPPROTO_TCP:
			{
			if ( PayloadLen() < sizeof(struct tcphdr) )
				break;

			const struct tcphdr* tp = (const struct tcphdr*)data;
			auto tcp_hdr = make_intrusive<RecordVal>(tcp_hdr_type);

			int tcp_hdr_len = tp->th_off * 4;

			// account for cases in which the payload length in the TCP header is not set,
			// or is set to an impossible value. In these cases, return 0.
			int data_len = 0;
			auto payload_len = PayloadLen();
			if ( payload_len >= tcp_hdr_len )
				data_len = payload_len - tcp_hdr_len;

			tcp_hdr->Assign(0, val_mgr->Port(ntohs(tp->th_sport), TRANSPORT_TCP));
			tcp_hdr->Assign(1, val_mgr->Port(ntohs(tp->th_dport), TRANSPORT_TCP));
			tcp_hdr->Assign(2, static_cast<uint32_t>(ntohl(tp->th_seq)));
			tcp_hdr->Assign(3, static_cast<uint32_t>(ntohl(tp->th_ack)));
			tcp_hdr->Assign(4, tcp_hdr_len);
			tcp_hdr->Assign(5, data_len);
			tcp_hdr->Assign(6, tp->th_x2);
			tcp_hdr->Assign(7, tp->th_flags);
			tcp_hdr->Assign(8, ntohs(tp->th_win));

			pkt_hdr->Assign(sindex + 2, std::move(tcp_hdr));
			break;
			}

		case IPPROTO_UDP:
			{
			if ( PayloadLen() < sizeof(struct udphdr) )
				break;

			const struct udphdr* up = (const struct udphdr*)data;
			auto udp_hdr = make_intrusive<RecordVal>(udp_hdr_type);

			udp_hdr->Assign(0, val_mgr->Port(ntohs(up->uh_sport), TRANSPORT_UDP));
			udp_hdr->Assign(1, val_mgr->Port(ntohs(up->uh_dport), TRANSPORT_UDP));
			udp_hdr->Assign(2, ntohs(up->uh_ulen));

			pkt_hdr->Assign(sindex + 3, std::move(udp_hdr));
			break;
			}

		case IPPROTO_ICMP:
			{
			if ( PayloadLen() < sizeof(struct icmp) )
				break;

			const struct icmp* icmpp = (const struct icmp*)data;
			auto icmp_hdr = make_intrusive<RecordVal>(icmp_hdr_type);

			icmp_hdr->Assign(0, icmpp->icmp_type);

			pkt_hdr->Assign(sindex + 4, std::move(icmp_hdr));
			break;
			}

		case IPPROTO_ICMPV6:
			{
			if ( PayloadLen() < sizeof(struct icmp6_hdr) )
				break;

			const struct icmp6_hdr* icmpp = (const struct icmp6_hdr*)data;
			auto icmp_hdr = make_intrusive<RecordVal>(icmp_hdr_type);

			icmp_hdr->Assign(0, icmpp->icmp6_type);

			pkt_hdr->Assign(sindex + 4, std::move(icmp_hdr));
			break;
			}

		default:
			{
			// This is not a protocol we understand.
			break;
			}
		}

	return pkt_hdr;
	}

static inline bool isIPv6ExtHeader(uint8_t type)
	{
	switch ( type )
		{
		case IPPROTO_HOPOPTS:
		case IPPROTO_ROUTING:
		case IPPROTO_DSTOPTS:
		case IPPROTO_FRAGMENT:
		case IPPROTO_AH:
		case IPPROTO_ESP:
		case IPPROTO_MOBILITY:
			return true;
		default:
			return false;
		}
	}

IPv6_Hdr_Chain::~IPv6_Hdr_Chain()
	{
	for ( size_t i = 0; i < chain.size(); ++i )
		delete chain[i];
	delete homeAddr;
	delete finalDst;
	}

void IPv6_Hdr_Chain::Init(const struct ip6_hdr* ip6, int total_len, bool set_next, uint16_t next)
	{
	length = 0;
	uint8_t current_type, next_type;
	next_type = IPPROTO_IPV6;
	const u_char* hdrs = (const u_char*)ip6;

	if ( total_len < (int)sizeof(struct ip6_hdr) )
		{
		reporter->InternalWarning("truncated IP header in IPv6_HdrChain::Init");
		return;
		}

	do
		{
		// We can't determine a given header's length if there's less than
		// two bytes of data available (2nd byte of extension headers is length)
		if ( total_len < 2 )
			return;

		current_type = next_type;
		IPv6_Hdr* p = new IPv6_Hdr(current_type, hdrs);

		next_type = p->NextHdr();
		uint16_t cur_len = p->Length();

		// If this header is truncated, don't add it to chain, don't go further.
		if ( cur_len > total_len )
			{
			delete p;
			return;
			}

		if ( set_next && next_type == IPPROTO_FRAGMENT )
			{
			p->ChangeNext(next);
			next_type = next;
			}

		chain.push_back(p);

		// Check for routing headers and remember final destination address.
		if ( current_type == IPPROTO_ROUTING )
			ProcessRoutingHeader((const struct ip6_rthdr*)hdrs, cur_len);

		// Only Mobile IPv6 has a destination option we care about right now.
		if ( current_type == IPPROTO_DSTOPTS )
			ProcessDstOpts((const struct ip6_dest*)hdrs, cur_len);

		hdrs += cur_len;
		length += cur_len;
		total_len -= cur_len;

		} while ( current_type != IPPROTO_FRAGMENT && current_type != IPPROTO_ESP &&
		          current_type != IPPROTO_MOBILITY && isIPv6ExtHeader(next_type) );
	}

bool IPv6_Hdr_Chain::IsFragment() const
	{
	if ( chain.empty() )
		{
		reporter->InternalWarning("empty IPv6 header chain");
		return false;
		}

	return chain[chain.size() - 1]->Type() == IPPROTO_FRAGMENT;
	}

IPAddr IPv6_Hdr_Chain::SrcAddr() const
	{
	if ( homeAddr )
		return IPAddr(*homeAddr);
	if ( chain.empty() )
		{
		reporter->InternalWarning("empty IPv6 header chain");
		return IPAddr();
		}

	return IPAddr(((const struct ip6_hdr*)(chain[0]->Data()))->ip6_src);
	}

IPAddr IPv6_Hdr_Chain::DstAddr() const
	{
	if ( finalDst )
		return IPAddr(*finalDst);

	if ( chain.empty() )
		{
		reporter->InternalWarning("empty IPv6 header chain");
		return IPAddr();
		}

	return IPAddr(((const struct ip6_hdr*)(chain[0]->Data()))->ip6_dst);
	}

void IPv6_Hdr_Chain::ProcessRoutingHeader(const struct ip6_rthdr* r, uint16_t len)
	{
	if ( finalDst )
		{
		// RFC 2460 section 4.1 says Routing should occur at most once.
		reporter->Weird(SrcAddr(), DstAddr(), "multiple_routing_headers");
		return;
		}

	// Last 16 bytes of header (for all known types) is the address we want.
	const in6_addr* addr = (const in6_addr*)(((const u_char*)r) + len - 16);

	switch ( r->ip6r_type )
		{
		case 0: // Defined by RFC 2460, deprecated by RFC 5095
			{
			if ( r->ip6r_segleft > 0 && r->ip6r_len >= 2 )
				{
				if ( r->ip6r_len % 2 == 0 )
					finalDst = new IPAddr(*addr);
				else
					reporter->Weird(SrcAddr(), DstAddr(), "odd_routing0_len");
				}

			// Always raise a weird since this type is deprecated.
			reporter->Weird(SrcAddr(), DstAddr(), "routing0_hdr");
			}
			break;

		case 2: // Defined by Mobile IPv6 RFC 6275.
			{
			if ( r->ip6r_segleft > 0 )
				{
				if ( r->ip6r_len == 2 )
					finalDst = new IPAddr(*addr);
				else
					reporter->Weird(SrcAddr(), DstAddr(), "bad_routing2_len");
				}
			}
			break;

		default:
			reporter->Weird(SrcAddr(), DstAddr(), "unknown_routing_type",
			                util::fmt("%d", r->ip6r_type));
			break;
		}
	}

void IPv6_Hdr_Chain::ProcessDstOpts(const struct ip6_dest* d, uint16_t len)
	{
	// Skip two bytes to get the beginning of the first option structure. These
	// two bytes are the protocol for the next header and extension header length,
	// already known to exist before calling this method.  See header format:
	// https://datatracker.ietf.org/doc/html/rfc8200#section-4.6
	assert(len >= 2);

	const u_char* data = (const u_char*)d;
	len -= 2 * sizeof(uint8_t);
	data += 2 * sizeof(uint8_t);

	while ( len > 0 )
		{
		const struct ip6_opt* opt = (const struct ip6_opt*)data;
		switch ( opt->ip6o_type )
			{
			case 0:
				// If option type is zero, it's a Pad0 and can be just a single
				// byte in width. Skip over it.
				data += sizeof(uint8_t);
				len -= sizeof(uint8_t);
				break;
			default:
				{
				// Double-check that the len can hold the whole option structure.
				// Otherwise we get a buffer-overflow when we check the option_len.
				// Also check that it holds everything for the option itself.
				if ( len < sizeof(struct ip6_opt) || len < sizeof(struct ip6_opt) + opt->ip6o_len )
					{
					reporter->Weird(SrcAddr(), DstAddr(), "bad_ipv6_dest_opt_len");
					len = 0;
					break;
					}

				if ( opt->ip6o_type ==
				     201 ) // Home Address Option, Mobile IPv6 RFC 6275 section 6.3
					{
					if ( opt->ip6o_len == sizeof(struct in6_addr) )
						{
						if ( homeAddr )
							reporter->Weird(SrcAddr(), DstAddr(), "multiple_home_addr_opts");
						else
							homeAddr = new IPAddr(
								*((const in6_addr*)(data + sizeof(struct ip6_opt))));
						}
					else
						reporter->Weird(SrcAddr(), DstAddr(), "bad_home_addr_len");
					}

				data += sizeof(struct ip6_opt) + opt->ip6o_len;
				len -= sizeof(struct ip6_opt) + opt->ip6o_len;
				}
				break;
			}
		}
	}

VectorValPtr IPv6_Hdr_Chain::ToVal() const
	{
	static auto ip6_ext_hdr_type = id::find_type<RecordType>("ip6_ext_hdr");
	static auto ip6_hopopts_type = id::find_type<RecordType>("ip6_hopopts");
	static auto ip6_dstopts_type = id::find_type<RecordType>("ip6_dstopts");
	static auto ip6_routing_type = id::find_type<RecordType>("ip6_routing");
	static auto ip6_fragment_type = id::find_type<RecordType>("ip6_fragment");
	static auto ip6_ah_type = id::find_type<RecordType>("ip6_ah");
	static auto ip6_esp_type = id::find_type<RecordType>("ip6_esp");
	static auto ip6_ext_hdr_chain_type = id::find_type<VectorType>("ip6_ext_hdr_chain");
	auto rval = make_intrusive<VectorVal>(ip6_ext_hdr_chain_type);

	for ( size_t i = 1; i < chain.size(); ++i )
		{
		auto v = chain[i]->ToVal();
		auto ext_hdr = make_intrusive<RecordVal>(ip6_ext_hdr_type);
		uint8_t type = chain[i]->Type();
		ext_hdr->Assign(0, type);

		switch ( type )
			{
			case IPPROTO_HOPOPTS:
				ext_hdr->Assign(1, std::move(v));
				break;
			case IPPROTO_DSTOPTS:
				ext_hdr->Assign(2, std::move(v));
				break;
			case IPPROTO_ROUTING:
				ext_hdr->Assign(3, std::move(v));
				break;
			case IPPROTO_FRAGMENT:
				ext_hdr->Assign(4, std::move(v));
				break;
			case IPPROTO_AH:
				ext_hdr->Assign(5, std::move(v));
				break;
			case IPPROTO_ESP:
				ext_hdr->Assign(6, std::move(v));
				break;
			case IPPROTO_MOBILITY:
				ext_hdr->Assign(7, std::move(v));
				break;
			default:
				reporter->InternalWarning("IPv6_Hdr_Chain bad header %d", type);
				continue;
			}

		rval->Assign(rval->Size(), std::move(ext_hdr));
		}

	return rval;
	}

IP_Hdr* IP_Hdr::Copy() const
	{
	char* new_hdr = new char[HdrLen()];

	if ( ip4 )
		{
		memcpy(new_hdr, ip4, HdrLen());
		return new IP_Hdr((const struct ip*)new_hdr, true);
		}

	memcpy(new_hdr, ip6, HdrLen());
	const struct ip6_hdr* new_ip6 = (const struct ip6_hdr*)new_hdr;
	IPv6_Hdr_Chain* new_ip6_hdrs = ip6_hdrs->Copy(new_ip6);
	return new IP_Hdr(new_ip6, true, 0, new_ip6_hdrs);
	}

IPv6_Hdr_Chain* IPv6_Hdr_Chain::Copy(const ip6_hdr* new_hdr) const
	{
	IPv6_Hdr_Chain* rval = new IPv6_Hdr_Chain;
	rval->length = length;

	if ( homeAddr )
		rval->homeAddr = new IPAddr(*homeAddr);

	if ( finalDst )
		rval->finalDst = new IPAddr(*finalDst);

	if ( chain.empty() )
		{
		reporter->InternalWarning("empty IPv6 header chain");
		delete rval;
		return nullptr;
		}

	const u_char* new_data = (const u_char*)new_hdr;
	const u_char* old_data = chain[0]->Data();

	for ( size_t i = 0; i < chain.size(); ++i )
		{
		int off = chain[i]->Data() - old_data;
		rval->chain.push_back(new IPv6_Hdr(chain[i]->Type(), new_data + off));
		}

	return rval;
	}

	} // namespace zeek