ipv6.h

00001 /*
00002  * Copyright (c) 2013-2017, Arm Limited and affiliates.
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 
00018 #ifndef _IPV6_H
00019 #define _IPV6_H
00020 
00021 #include "Core/include/ns_buffer.h"
00022 #include "Common_Protocols/ipv6_constants.h"
00023 
00024 extern uint16_t ipv6_header_size_required(buffer_t *buf);
00025 extern uint16_t ipv6_max_unfragmented_payload(buffer_t *buf, uint16_t mtu_limit);
00026 extern uint16_t ipv6_mtu(buffer_t *buf);
00027 
00028 extern buffer_routing_info_t *ipv6_buffer_route_to(buffer_t *buf, const uint8_t *next_hop, struct protocol_interface_info_entry *next_if);
00029 extern buffer_routing_info_t *ipv6_buffer_route(buffer_t *buf);
00030 
00031 typedef enum ipv6_exthdr_stage {
00032     IPV6_EXTHDR_SIZE,
00033     IPV6_EXTHDR_INSERT,
00034     IPV6_EXTHDR_MODIFY
00035 } ipv6_exthdr_stage_t;
00036 
00037 #define IPV6_EXTHDR_MODIFY_TUNNEL 1
00038 
00039 /* Hooks for routing code to insert/modify IPv6 extension headers.
00040  *
00041  * IPV6_EXTHDR_SIZE: buffer not yet fully formed, but we know the final
00042  * destination. Can perform routing decision. Call should set result to total size
00043  * of extension header that would be inserted by IPV6_EXTHDR_INSERT.
00044  *
00045  * IPV6_EXTHDR_INSERT: we are about to add IP header - provider can
00046  * prepend extension headers, and modify options.type to new outer NH.
00047  * (We do not support extension headers from more than one source per packet).
00048  * These headers can be placeholders, with filling deferred until
00049  * IPV6_EXTHDR_MODIFY. If a source routing header is inserted, buffer dst_sa
00050  * should be changed from final destination to next IP destination.
00051  * XXX no - won't work. Separate mechanism for varying IP dest?
00052  *
00053  * IPV6_EXTHDR_MODIFY: the buffer contains an existing complete IP packet,
00054  * possibly generated internally, and possibly received externally. Provider
00055  * can update fields in extension headers it knows.
00056  *
00057  * If it needs to insert headers that are not present, it can force insertion
00058  * into a tunnel, by:
00059  *    setting dst_sa and src_sa appropriate for the tunnel endpoints
00060  *      XXX does this work out okay with dest cache and PMTU?
00061  *    updating route info like next hop if necessary (probably not)
00062  *    returning IPV6_EXTHDR_MODIFY_TUNNEL
00063  * During new header formation for the tunnel, IPV6_EXTHDR_INSERT will be
00064  * called again, and obviously it must ensure headers are inserted so that
00065  * IPV6_EXTHDR_MODIFY doesn't request to tunnel a second time.
00066  *
00067  * In all cases, a negative value in result indicates error.
00068  */
00069 typedef buffer_t *ipv6_exthdr_provider_fn_t(buffer_t *buf, ipv6_exthdr_stage_t stage, int16_t *result);
00070 void ipv6_set_exthdr_provider(ipv6_route_src_t src, ipv6_exthdr_provider_fn_t *fn);
00071 
00072 extern buffer_t *ipv6_down(buffer_t *buf);
00073 extern buffer_t *ipv6_forwarding_down(buffer_t *buf);
00074 extern buffer_t *ipv6_forwarding_up(buffer_t *buf);
00075 
00076 void ipv6_transmit_multicast_on_interface(buffer_t *buf, struct protocol_interface_info_entry *cur);
00077 
00078 #endif /* _IPV6_H */