diff options
Diffstat (limited to 'src/vnet/ip')
| -rw-r--r-- | src/vnet/ip/ip4_to_ip6.h | 577 | ||||
| -rw-r--r-- | src/vnet/ip/ip6_to_ip4.h | 571 |
2 files changed, 1148 insertions, 0 deletions
diff --git a/src/vnet/ip/ip4_to_ip6.h b/src/vnet/ip/ip4_to_ip6.h new file mode 100644 index 00000000000..96b8bf1e676 --- /dev/null +++ b/src/vnet/ip/ip4_to_ip6.h @@ -0,0 +1,577 @@ +/* + * Copyright (c) 2017 Cisco and/or its affiliates. + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +/** + * @file + * @brief IPv4 to IPv6 translation + */ +#ifndef __included_ip4_to_ip6_h__ +#define __included_ip4_to_ip6_h__ + +#include <vnet/ip/ip.h> + + +/** + * IPv4 to IPv6 set call back function type + */ +typedef int (*ip4_to_ip6_set_fn_t) (ip4_header_t * ip4, ip6_header_t * ip6, + void *ctx); + +/* *INDENT-OFF* */ +static u8 icmp_to_icmp6_updater_pointer_table[] = + { 0, 1, 4, 4, ~0, + ~0, ~0, ~0, 7, 6, + ~0, ~0, 8, 8, 8, + 8, 24, 24, 24, 24 + }; +/* *INDENT-ON* */ + +#define frag_id_4to6(id) (id) + +/** + * @brief Get TCP/UDP port number or ICMP id from IPv4 packet. + * + * @param ip4 IPv4 header. + * @param sender 1 get sender port, 0 get receiver port. + * + * @returns Port number on success, 0 otherwise. + */ +always_inline u16 +ip4_get_port (ip4_header_t * ip, u8 sender) +{ + if (ip->ip_version_and_header_length != 0x45 || + ip4_get_fragment_offset (ip)) + return 0; + + if (PREDICT_TRUE ((ip->protocol == IP_PROTOCOL_TCP) || + (ip->protocol == IP_PROTOCOL_UDP))) + { + udp_header_t *udp = (void *) (ip + 1); + return (sender) ? udp->src_port : udp->dst_port; + } + else if (ip->protocol == IP_PROTOCOL_ICMP) + { + icmp46_header_t *icmp = (void *) (ip + 1); + if (icmp->type == ICMP4_echo_request || icmp->type == ICMP4_echo_reply) + { + return *((u16 *) (icmp + 1)); + } + else if (clib_net_to_host_u16 (ip->length) >= 64) + { + ip = (ip4_header_t *) (icmp + 2); + if (PREDICT_TRUE ((ip->protocol == IP_PROTOCOL_TCP) || + (ip->protocol == IP_PROTOCOL_UDP))) + { + udp_header_t *udp = (void *) (ip + 1); + return (sender) ? udp->dst_port : udp->src_port; + } + else if (ip->protocol == IP_PROTOCOL_ICMP) + { + icmp46_header_t *icmp = (void *) (ip + 1); + if (icmp->type == ICMP4_echo_request || + icmp->type == ICMP4_echo_reply) + { + return *((u16 *) (icmp + 1)); + } + } + } + } + return 0; +} + +/** + * @brief Convert type and code value from ICMP4 to ICMP6. + * + * @param icmp ICMP header. + * @param inner_ip4 Inner IPv4 header if present, 0 otherwise. + * + * @returns 0 on success, non-zero value otherwise. + */ +always_inline int +icmp_to_icmp6_header (icmp46_header_t * icmp, ip4_header_t ** inner_ip4) +{ + *inner_ip4 = NULL; + switch (icmp->type) + { + case ICMP4_echo_reply: + icmp->type = ICMP6_echo_reply; + break; + case ICMP4_echo_request: + icmp->type = ICMP6_echo_request; + break; + case ICMP4_destination_unreachable: + *inner_ip4 = (ip4_header_t *) (((u8 *) icmp) + 8); + + switch (icmp->code) + { + case ICMP4_destination_unreachable_destination_unreachable_net: //0 + case ICMP4_destination_unreachable_destination_unreachable_host: //1 + icmp->type = ICMP6_destination_unreachable; + icmp->code = ICMP6_destination_unreachable_no_route_to_destination; + break; + case ICMP4_destination_unreachable_protocol_unreachable: //2 + icmp->type = ICMP6_parameter_problem; + icmp->code = ICMP6_parameter_problem_unrecognized_next_header; + break; + case ICMP4_destination_unreachable_port_unreachable: //3 + icmp->type = ICMP6_destination_unreachable; + icmp->code = ICMP6_destination_unreachable_port_unreachable; + break; + case ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set: //4 + icmp->type = + ICMP6_packet_too_big; + icmp->code = 0; + { + u32 advertised_mtu = clib_net_to_host_u32 (*((u32 *) (icmp + 1))); + if (advertised_mtu) + advertised_mtu += 20; + else + advertised_mtu = 1000; //FIXME ! (RFC 1191 - plateau value) + + //FIXME: = minimum(advertised MTU+20, MTU_of_IPv6_nexthop, (MTU_of_IPv4_nexthop)+20) + *((u32 *) (icmp + 1)) = clib_host_to_net_u32 (advertised_mtu); + } + break; + + case ICMP4_destination_unreachable_source_route_failed: //5 + case ICMP4_destination_unreachable_destination_network_unknown: //6 + case ICMP4_destination_unreachable_destination_host_unknown: //7 + case ICMP4_destination_unreachable_source_host_isolated: //8 + case ICMP4_destination_unreachable_network_unreachable_for_type_of_service: //11 + case ICMP4_destination_unreachable_host_unreachable_for_type_of_service: //12 + icmp->type = + ICMP6_destination_unreachable; + icmp->code = ICMP6_destination_unreachable_no_route_to_destination; + break; + case ICMP4_destination_unreachable_network_administratively_prohibited: //9 + case ICMP4_destination_unreachable_host_administratively_prohibited: //10 + case ICMP4_destination_unreachable_communication_administratively_prohibited: //13 + case ICMP4_destination_unreachable_precedence_cutoff_in_effect: //15 + icmp->type = ICMP6_destination_unreachable; + icmp->code = + ICMP6_destination_unreachable_destination_administratively_prohibited; + break; + case ICMP4_destination_unreachable_host_precedence_violation: //14 + default: + return -1; + } + break; + + case ICMP4_time_exceeded: //11 + *inner_ip4 = (ip4_header_t *) (((u8 *) icmp) + 8); + icmp->type = ICMP6_time_exceeded; + break; + + case ICMP4_parameter_problem: + *inner_ip4 = (ip4_header_t *) (((u8 *) icmp) + 8); + + switch (icmp->code) + { + case ICMP4_parameter_problem_pointer_indicates_error: + case ICMP4_parameter_problem_bad_length: + icmp->type = ICMP6_parameter_problem; + icmp->code = ICMP6_parameter_problem_erroneous_header_field; + { + u8 ptr = + icmp_to_icmp6_updater_pointer_table[*((u8 *) (icmp + 1))]; + if (ptr == 0xff) + return -1; + + *((u32 *) (icmp + 1)) = clib_host_to_net_u32 (ptr); + } + break; + default: + //All other codes cause error + return -1; + } + break; + + default: + //All other types cause error + return -1; + break; + } + return 0; +} + +/** + * @brief Translate ICMP4 packet to ICMP6. + * + * @param p Buffer to translate. + * @param fn The function to translate outer header. + * @param ctx A context passed in the outer header translate function. + * @param inner_fn The function to translate inner header. + * @param inner_ctx A context passed in the inner header translate function. + * + * @returns 0 on success, non-zero value otherwise. + */ +always_inline int +icmp_to_icmp6 (vlib_buffer_t * p, ip4_to_ip6_set_fn_t fn, void *ctx, + ip4_to_ip6_set_fn_t inner_fn, void *inner_ctx) +{ + ip4_header_t *ip4, *inner_ip4; + ip6_header_t *ip6, *inner_ip6; + u32 ip_len; + icmp46_header_t *icmp; + ip_csum_t csum; + ip6_frag_hdr_t *inner_frag; + u32 inner_frag_id; + u32 inner_frag_offset; + u8 inner_frag_more; + u16 *inner_L4_checksum = 0; + int rv; + + ip4 = vlib_buffer_get_current (p); + ip_len = clib_net_to_host_u16 (ip4->length); + ASSERT (ip_len <= p->current_length); + + icmp = (icmp46_header_t *) (ip4 + 1); + if (icmp_to_icmp6_header (icmp, &inner_ip4)) + return -1; + + if (inner_ip4) + { + //We have 2 headers to translate. + //We need to make some room in the middle of the packet + if (PREDICT_FALSE (ip4_is_fragment (inner_ip4))) + { + //Here it starts getting really tricky + //We will add a fragmentation header in the inner packet + + if (!ip4_is_first_fragment (inner_ip4)) + { + //For now we do not handle unless it is the first fragment + //Ideally we should handle the case as we are in slow path already + return -1; + } + + vlib_buffer_advance (p, + -2 * (sizeof (*ip6) - sizeof (*ip4)) - + sizeof (*inner_frag)); + ip6 = vlib_buffer_get_current (p); + clib_memcpy (u8_ptr_add (ip6, sizeof (*ip6) - sizeof (*ip4)), ip4, + 20 + 8); + ip4 = + (ip4_header_t *) u8_ptr_add (ip6, sizeof (*ip6) - sizeof (*ip4)); + icmp = (icmp46_header_t *) (ip4 + 1); + + inner_ip6 = + (ip6_header_t *) u8_ptr_add (inner_ip4, + sizeof (*ip4) - sizeof (*ip6) - + sizeof (*inner_frag)); + inner_frag = + (ip6_frag_hdr_t *) u8_ptr_add (inner_ip6, sizeof (*inner_ip6)); + ip6->payload_length = + u16_net_add (ip4->length, + sizeof (*ip6) - 2 * sizeof (*ip4) + + sizeof (*inner_frag)); + inner_frag_id = frag_id_4to6 (inner_ip4->fragment_id); + inner_frag_offset = ip4_get_fragment_offset (inner_ip4); + inner_frag_more = + ! !(inner_ip4->flags_and_fragment_offset & + clib_net_to_host_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS)); + } + else + { + vlib_buffer_advance (p, -2 * (sizeof (*ip6) - sizeof (*ip4))); + ip6 = vlib_buffer_get_current (p); + clib_memcpy (u8_ptr_add (ip6, sizeof (*ip6) - sizeof (*ip4)), ip4, + 20 + 8); + ip4 = + (ip4_header_t *) u8_ptr_add (ip6, sizeof (*ip6) - sizeof (*ip4)); + icmp = (icmp46_header_t *) u8_ptr_add (ip4, sizeof (*ip4)); + inner_ip6 = + (ip6_header_t *) u8_ptr_add (inner_ip4, + sizeof (*ip4) - sizeof (*ip6)); + ip6->payload_length = + u16_net_add (ip4->length, sizeof (*ip6) - 2 * sizeof (*ip4)); + inner_frag = NULL; + } + + if (PREDICT_TRUE (inner_ip4->protocol == IP_PROTOCOL_TCP)) + { + inner_L4_checksum = &((tcp_header_t *) (inner_ip4 + 1))->checksum; + *inner_L4_checksum = + ip_csum_fold (ip_csum_sub_even + (*inner_L4_checksum, + *((u64 *) (&inner_ip4->src_address)))); + } + else if (PREDICT_TRUE (inner_ip4->protocol == IP_PROTOCOL_UDP)) + { + inner_L4_checksum = &((udp_header_t *) (inner_ip4 + 1))->checksum; + if (!*inner_L4_checksum) + { + return -1; + } + *inner_L4_checksum = + ip_csum_fold (ip_csum_sub_even + (*inner_L4_checksum, + *((u64 *) (&inner_ip4->src_address)))); + } + else if (inner_ip4->protocol == IP_PROTOCOL_ICMP) + { + //We have an ICMP inside an ICMP + //It needs to be translated, but not for error ICMP messages + icmp46_header_t *inner_icmp = (icmp46_header_t *) (inner_ip4 + 1); + csum = inner_icmp->checksum; + //Only types ICMP4_echo_request and ICMP4_echo_reply are handled by icmp_to_icmp6_header + csum = ip_csum_sub_even (csum, *((u16 *) inner_icmp)); + inner_icmp->type = (inner_icmp->type == ICMP4_echo_request) ? + ICMP6_echo_request : ICMP6_echo_reply; + csum = ip_csum_add_even (csum, *((u16 *) inner_icmp)); + csum = + ip_csum_add_even (csum, clib_host_to_net_u16 (IP_PROTOCOL_ICMP6)); + csum = + ip_csum_add_even (csum, inner_ip4->length - sizeof (*inner_ip4)); + inner_icmp->checksum = ip_csum_fold (csum); + inner_L4_checksum = &inner_icmp->checksum; + inner_ip4->protocol = IP_PROTOCOL_ICMP6; + } + else + { + /* To shut up Coverity */ + os_panic (); + } + + csum = *inner_L4_checksum; //Initial checksum of the inner L4 header + + inner_ip6->ip_version_traffic_class_and_flow_label = + clib_host_to_net_u32 ((6 << 28) + (inner_ip4->tos << 20)); + inner_ip6->payload_length = + u16_net_add (inner_ip4->length, -sizeof (*inner_ip4)); + inner_ip6->hop_limit = inner_ip4->ttl; + inner_ip6->protocol = inner_ip4->protocol; + + if ((rv = inner_fn (inner_ip4, inner_ip6, inner_ctx)) != 0) + return rv; + + if (PREDICT_FALSE (inner_frag != NULL)) + { + inner_frag->next_hdr = inner_ip6->protocol; + inner_frag->identification = inner_frag_id; + inner_frag->rsv = 0; + inner_frag->fragment_offset_and_more = + ip6_frag_hdr_offset_and_more (inner_frag_offset, inner_frag_more); + inner_ip6->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION; + inner_ip6->payload_length = + clib_host_to_net_u16 (clib_net_to_host_u16 + (inner_ip6->payload_length) + + sizeof (*inner_frag)); + } + + csum = ip_csum_add_even (csum, inner_ip6->src_address.as_u64[0]); + csum = ip_csum_add_even (csum, inner_ip6->src_address.as_u64[1]); + csum = ip_csum_add_even (csum, inner_ip6->dst_address.as_u64[0]); + csum = ip_csum_add_even (csum, inner_ip6->dst_address.as_u64[1]); + *inner_L4_checksum = ip_csum_fold (csum); + } + else + { + vlib_buffer_advance (p, sizeof (*ip4) - sizeof (*ip6)); + ip6 = vlib_buffer_get_current (p); + ip6->payload_length = + clib_host_to_net_u16 (clib_net_to_host_u16 (ip4->length) - + sizeof (*ip4)); + } + + //Translate outer IPv6 + ip6->ip_version_traffic_class_and_flow_label = + clib_host_to_net_u32 ((6 << 28) + (ip4->tos << 20)); + + ip6->hop_limit = ip4->ttl; + ip6->protocol = IP_PROTOCOL_ICMP6; + + if ((rv = fn (ip4, ip6, ctx)) != 0) + return rv; + + //Truncate when the packet exceeds the minimal IPv6 MTU + if (p->current_length > 1280) + { + ip6->payload_length = clib_host_to_net_u16 (1280 - sizeof (*ip6)); + p->current_length = 1280; //Looks too simple to be correct... + } + + //Recompute ICMP checksum + icmp->checksum = 0; + csum = ip_csum_with_carry (0, ip6->payload_length); + csum = ip_csum_with_carry (csum, clib_host_to_net_u16 (ip6->protocol)); + csum = ip_csum_with_carry (csum, ip6->src_address.as_u64[0]); + csum = ip_csum_with_carry (csum, ip6->src_address.as_u64[1]); + csum = ip_csum_with_carry (csum, ip6->dst_address.as_u64[0]); + csum = ip_csum_with_carry (csum, ip6->dst_address.as_u64[1]); + csum = + ip_incremental_checksum (csum, icmp, + clib_net_to_host_u16 (ip6->payload_length)); + icmp->checksum = ~ip_csum_fold (csum); + + return 0; +} + +/** + * @brief Translate IPv4 fragmented packet to IPv6. + * + * @param p Buffer to translate. + * @param fn The function to translate header. + * @param ctx A context passed in the header translate function. + * + * @returns 0 on success, non-zero value otherwise. + */ +always_inline int +ip4_to_ip6_fragmented (vlib_buffer_t * p, ip4_to_ip6_set_fn_t fn, void *ctx) +{ + ip4_header_t *ip4; + ip6_header_t *ip6; + ip6_frag_hdr_t *frag; + int rv; + + ip4 = vlib_buffer_get_current (p); + frag = (ip6_frag_hdr_t *) u8_ptr_add (ip4, sizeof (*ip4) - sizeof (*frag)); + ip6 = + (ip6_header_t *) u8_ptr_add (ip4, + sizeof (*ip4) - sizeof (*frag) - + sizeof (*ip6)); + vlib_buffer_advance (p, sizeof (*ip4) - sizeof (*ip6) - sizeof (*frag)); + + //We know that the protocol was one of ICMP, TCP or UDP + //because the first fragment was found and cached + frag->next_hdr = + (ip4->protocol == IP_PROTOCOL_ICMP) ? IP_PROTOCOL_ICMP6 : ip4->protocol; + frag->identification = frag_id_4to6 (ip4->fragment_id); + frag->rsv = 0; + frag->fragment_offset_and_more = + ip6_frag_hdr_offset_and_more (ip4_get_fragment_offset (ip4), + clib_net_to_host_u16 + (ip4->flags_and_fragment_offset) & + IP4_HEADER_FLAG_MORE_FRAGMENTS); + + ip6->ip_version_traffic_class_and_flow_label = + clib_host_to_net_u32 ((6 << 28) + (ip4->tos << 20)); + ip6->payload_length = + clib_host_to_net_u16 (clib_net_to_host_u16 (ip4->length) - + sizeof (*ip4) + sizeof (*frag)); + ip6->hop_limit = ip4->ttl; + ip6->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION; + + if ((rv = fn (ip4, ip6, ctx)) != 0) + return rv; + + return 0; +} + +/** + * @brief Translate IPv4 UDP/TCP packet to IPv6. + * + * @param p Buffer to translate. + * @param fn The function to translate header. + * @param ctx A context passed in the header translate function. + * + * @returns 0 on success, non-zero value otherwise. + */ +always_inline int +ip4_to_ip6_tcp_udp (vlib_buffer_t * p, ip4_to_ip6_set_fn_t fn, void *ctx) +{ + ip4_header_t *ip4; + ip6_header_t *ip6; + ip_csum_t csum; + u16 *checksum; + ip6_frag_hdr_t *frag; + u32 frag_id; + int rv; + + ip4 = vlib_buffer_get_current (p); + + if (ip4->protocol == IP_PROTOCOL_UDP) + { + udp_header_t *udp = ip4_next_header (ip4); + checksum = &udp->checksum; + + //UDP checksum is optional over IPv4 but mandatory for IPv6 + //We do not check udp->length sanity but use our safe computed value instead + if (PREDICT_FALSE (!checksum)) + { + u16 udp_len = clib_host_to_net_u16 (ip4->length) - sizeof (*ip4); + csum = ip_incremental_checksum (0, udp, udp_len); + csum = ip_csum_with_carry (csum, clib_host_to_net_u16 (udp_len)); + csum = + ip_csum_with_carry (csum, clib_host_to_net_u16 (IP_PROTOCOL_UDP)); + csum = ip_csum_with_carry (csum, *((u64 *) (&ip4->src_address))); + *checksum = ~ip_csum_fold (csum); + } + } + else + { + tcp_header_t *tcp = ip4_next_header (ip4); + checksum = &tcp->checksum; + } + + csum = ip_csum_sub_even (*checksum, ip4->src_address.as_u32); + csum = ip_csum_sub_even (csum, ip4->dst_address.as_u32); + + // Deal with fragmented packets + if (PREDICT_FALSE (ip4->flags_and_fragment_offset & + clib_host_to_net_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS))) + { + ip6 = + (ip6_header_t *) u8_ptr_add (ip4, + sizeof (*ip4) - sizeof (*ip6) - + sizeof (*frag)); + frag = + (ip6_frag_hdr_t *) u8_ptr_add (ip4, sizeof (*ip4) - sizeof (*frag)); + frag_id = frag_id_4to6 (ip4->fragment_id); + vlib_buffer_advance (p, sizeof (*ip4) - sizeof (*ip6) - sizeof (*frag)); + } + else + { + ip6 = (ip6_header_t *) (((u8 *) ip4) + sizeof (*ip4) - sizeof (*ip6)); + vlib_buffer_advance (p, sizeof (*ip4) - sizeof (*ip6)); + frag = NULL; + } + + ip6->ip_version_traffic_class_and_flow_label = + clib_host_to_net_u32 ((6 << 28) + (ip4->tos << 20)); + ip6->payload_length = u16_net_add (ip4->length, -sizeof (*ip4)); + ip6->hop_limit = ip4->ttl; + ip6->protocol = ip4->protocol; + + if (PREDICT_FALSE (frag != NULL)) + { + frag->next_hdr = ip6->protocol; + frag->identification = frag_id; + frag->rsv = 0; + frag->fragment_offset_and_more = ip6_frag_hdr_offset_and_more (0, 1); + ip6->protocol = IP_PROTOCOL_IPV6_FRAGMENTATION; + ip6->payload_length = u16_net_add (ip6->payload_length, sizeof (*frag)); + } + + if ((rv = fn (ip4, ip6, ctx)) != 0) + return rv; + + csum = ip_csum_add_even (csum, ip6->src_address.as_u64[0]); + csum = ip_csum_add_even (csum, ip6->src_address.as_u64[1]); + csum = ip_csum_add_even (csum, ip6->dst_address.as_u64[0]); + csum = ip_csum_add_even (csum, ip6->dst_address.as_u64[1]); + *checksum = ip_csum_fold (csum); + + return 0; +} + +#endif /* __included_ip4_to_ip6_h__ */ + +/* + * fd.io coding-style-patch-verification: ON + * + * Local Variables: + * eval: (c-set-style "gnu") + * End: + */ diff --git a/src/vnet/ip/ip6_to_ip4.h b/src/vnet/ip/ip6_to_ip4.h new file mode 100644 index 00000000000..f5d56883263 --- /dev/null +++ b/src/vnet/ip/ip6_to_ip4.h @@ -0,0 +1,571 @@ +/* + * Copyright (c) 2017 Cisco and/or its affiliates. + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +/** + * @file + * @brief IPv6 to IPv4 translation + */ +#ifndef __included_ip6_to_ip4_h__ +#define __included_ip6_to_ip4_h__ + +#include <vnet/ip/ip.h> + +/** + * IPv6 to IPv4 set call back function type + */ +typedef int (*ip6_to_ip4_set_fn_t) (ip6_header_t * ip6, ip4_header_t * ip4, + void *ctx); + +/* *INDENT-OFF* */ +static u8 icmp6_to_icmp_updater_pointer_table[] = + { 0, 1, ~0, ~0, + 2, 2, 9, 8, + 12, 12, 12, 12, + 12, 12, 12, 12, + 12, 12, 12, 12, + 12, 12, 12, 12, + 24, 24, 24, 24, + 24, 24, 24, 24, + 24, 24, 24, 24, + 24, 24, 24, 24 + }; +/* *INDENT-ON* */ + +#define frag_id_6to4(id) ((id) ^ ((id) >> 16)) + +/** + * @brief Parse some useful information from IPv6 header. + * + * @param ip6 IPv6 header. + * @param buff_len Buffer length. + * @param l4_protocol L4 protocol number. + * @param l4_offset L4 header offset. + * @param frag_hdr_offset Fragment header offset if present, 0 otherwise. + * + * @returns 0 on success, non-zero value otherwise. + */ +static_always_inline int +ip6_parse (const ip6_header_t * ip6, u32 buff_len, + u8 * l4_protocol, u16 * l4_offset, u16 * frag_hdr_offset) +{ + if (ip6->protocol == IP_PROTOCOL_IPV6_FRAGMENTATION) + { + *l4_protocol = ((ip6_frag_hdr_t *) (ip6 + 1))->next_hdr; + *frag_hdr_offset = sizeof (*ip6); + *l4_offset = sizeof (*ip6) + sizeof (ip6_frag_hdr_t); + } + else + { + *l4_protocol = ip6->protocol; + *frag_hdr_offset = 0; + *l4_offset = sizeof (*ip6); + } + + return (buff_len < (*l4_offset + 4)) || + (clib_net_to_host_u16 (ip6->payload_length) < + (*l4_offset + 4 - sizeof (*ip6))); +} + +/** + * @brief Get TCP/UDP port number or ICMP id from IPv6 packet. + * + * @param ip6 IPv6 header. + * @param sender 1 get sender port, 0 get receiver port. + * @param buffer_len Buffer length. + * + * @returns Port number on success, 0 otherwise. + */ +always_inline u16 +ip6_get_port (ip6_header_t * ip6, u8 sender, u16 buffer_len) +{ + u8 l4_protocol; + u16 l4_offset; + u16 frag_offset; + u8 *l4; + + if (ip6_parse (ip6, buffer_len, &l4_protocol, &l4_offset, &frag_offset)) + return 0; + + if (frag_offset && + ip6_frag_hdr_offset (((ip6_frag_hdr_t *) + u8_ptr_add (ip6, frag_offset)))) + return 0; //Can't deal with non-first fragment for now + + l4 = u8_ptr_add (ip6, l4_offset); + if (l4_protocol == IP_PROTOCOL_TCP || l4_protocol == IP_PROTOCOL_UDP) + { + return (sender) ? ((udp_header_t *) (l4))->src_port : ((udp_header_t + *) + (l4))->dst_port; + } + else if (l4_protocol == IP_PROTOCOL_ICMP6) + { + icmp46_header_t *icmp = (icmp46_header_t *) (l4); + if (icmp->type == ICMP6_echo_request) + { + return (sender) ? ((u16 *) (icmp))[2] : -1; + } + else if (icmp->type == ICMP6_echo_reply) + { + return (sender) ? -1 : ((u16 *) (icmp))[2]; + } + } + return 0; +} + +/** + * @brief Convert type and code value from ICMP6 to ICMP4. + * + * @param icmp ICMP header. + * @param inner_ip6 Inner IPv6 header if present, 0 otherwise. + * + * @returns 0 on success, non-zero value otherwise. + */ +static_always_inline int +icmp6_to_icmp_header (icmp46_header_t * icmp, ip6_header_t ** inner_ip6) +{ + *inner_ip6 = NULL; + switch (icmp->type) + { + case ICMP6_echo_request: + icmp->type = ICMP4_echo_request; + break; + case ICMP6_echo_reply: + icmp->type = ICMP4_echo_reply; + break; + case ICMP6_destination_unreachable: + *inner_ip6 = (ip6_header_t *) u8_ptr_add (icmp, 8); + + switch (icmp->code) + { + case ICMP6_destination_unreachable_no_route_to_destination: //0 + case ICMP6_destination_unreachable_beyond_scope_of_source_address: //2 + case ICMP6_destination_unreachable_address_unreachable: //3 + icmp->type = ICMP4_destination_unreachable; + icmp->code = + ICMP4_destination_unreachable_destination_unreachable_host; + break; + case ICMP6_destination_unreachable_destination_administratively_prohibited: //1 + icmp->type = + ICMP4_destination_unreachable; + icmp->code = + ICMP4_destination_unreachable_communication_administratively_prohibited; + break; + case ICMP6_destination_unreachable_port_unreachable: + icmp->type = ICMP4_destination_unreachable; + icmp->code = ICMP4_destination_unreachable_port_unreachable; + break; + default: + return -1; + } + break; + case ICMP6_packet_too_big: + *inner_ip6 = (ip6_header_t *) u8_ptr_add (icmp, 8); + + icmp->type = ICMP4_destination_unreachable; + icmp->code = 4; + { + u32 advertised_mtu = clib_net_to_host_u32 (*((u32 *) (icmp + 1))); + advertised_mtu -= 20; + //FIXME: = minimum(advertised MTU-20, MTU_of_IPv4_nexthop, (MTU_of_IPv6_nexthop)-20) + ((u16 *) (icmp))[3] = clib_host_to_net_u16 (advertised_mtu); + } + break; + + case ICMP6_time_exceeded: + *inner_ip6 = (ip6_header_t *) u8_ptr_add (icmp, 8); + + icmp->type = ICMP4_time_exceeded; + break; + + case ICMP6_parameter_problem: + *inner_ip6 = (ip6_header_t *) u8_ptr_add (icmp, 8); + + switch (icmp->code) + { + case ICMP6_parameter_problem_erroneous_header_field: + icmp->type = ICMP4_parameter_problem; + icmp->code = ICMP4_parameter_problem_pointer_indicates_error; + u32 pointer = clib_net_to_host_u32 (*((u32 *) (icmp + 1))); + if (pointer >= 40) + return -1; + + ((u8 *) (icmp + 1))[0] = + icmp6_to_icmp_updater_pointer_table[pointer]; + break; + case ICMP6_parameter_problem_unrecognized_next_header: + icmp->type = ICMP4_destination_unreachable; + icmp->code = ICMP4_destination_unreachable_port_unreachable; + break; + case ICMP6_parameter_problem_unrecognized_option: + default: + return -1; + } + break; + default: + return -1; + break; + } + return 0; +} + +/** + * @brief Translate TOS value from IPv6 to IPv4. + * + * @param ip6 IPv6 header. + * + * @returns IPv4 TOS value. + */ +static_always_inline u8 +ip6_translate_tos (const ip6_header_t * ip6) +{ + return (clib_net_to_host_u32 (ip6->ip_version_traffic_class_and_flow_label) + & 0x0ff00000) >> 20; +} + +/** + * @brief Translate ICMP6 packet to ICMP4. + * + * @param p Buffer to translate. + * @param fn The function to translate outer header. + * @param ctx A context passed in the outer header translate function. + * @param inner_fn The function to translate inner header. + * @param inner_ctx A context passed in the inner header translate function. + * + * @returns 0 on success, non-zero value otherwise. + */ +always_inline int +icmp6_to_icmp (vlib_buffer_t * p, ip6_to_ip4_set_fn_t fn, void *ctx, + ip6_to_ip4_set_fn_t inner_fn, void *inner_ctx) +{ + ip6_header_t *ip6, *inner_ip6; + ip4_header_t *ip4, *inner_ip4; + u32 ip6_pay_len; + icmp46_header_t *icmp; + ip_csum_t csum; + int rv; + + ip6 = vlib_buffer_get_current (p); + ip6_pay_len = clib_net_to_host_u16 (ip6->payload_length); + icmp = (icmp46_header_t *) (ip6 + 1); + ASSERT (ip6_pay_len + sizeof (*ip6) <= p->current_length); + + //No extensions headers allowed here + if (ip6->protocol != IP_PROTOCOL_ICMP6) + return -1; + + //There are no fragmented ICMP messages, so no extension header for now + if (icmp6_to_icmp_header (icmp, &inner_ip6)) + return -1; + + if (inner_ip6) + { + u16 *inner_L4_checksum, inner_l4_offset, inner_frag_offset, + inner_frag_id; + u8 *inner_l4, inner_protocol; + + //We have two headers to translate + // FROM + // [ IPv6 ]<- ext ->[IC][ IPv6 ]<- ext ->[L4 header ... + // Handled cases: + // [ IPv6 ][IC][ IPv6 ][L4 header ... + // [ IPv6 ][IC][ IPv6 ][Fr][L4 header ... + // TO + // [ IPv4][IC][ IPv4][L4 header ... + + if (ip6_parse (inner_ip6, ip6_pay_len - 8, + &inner_protocol, &inner_l4_offset, &inner_frag_offset)) + return -1; + + inner_l4 = u8_ptr_add (inner_ip6, inner_l4_offset); + inner_ip4 = + (ip4_header_t *) u8_ptr_add (inner_l4, -sizeof (*inner_ip4)); + if (inner_frag_offset) + { + ip6_frag_hdr_t *inner_frag = + (ip6_frag_hdr_t *) u8_ptr_add (inner_ip6, inner_frag_offset); + inner_frag_id = frag_id_6to4 (inner_frag->identification); + } + else + { + inner_frag_id = 0; + } + + //Do the translation of the inner packet + if (inner_protocol == IP_PROTOCOL_TCP) + { + inner_L4_checksum = (u16 *) u8_ptr_add (inner_l4, 16); + } + else if (inner_protocol == IP_PROTOCOL_UDP) + { + inner_L4_checksum = (u16 *) u8_ptr_add (inner_l4, 6); + } + else if (inner_protocol == IP_PROTOCOL_ICMP6) + { + icmp46_header_t *inner_icmp = (icmp46_header_t *) inner_l4; + csum = inner_icmp->checksum; + csum = ip_csum_sub_even (csum, *((u16 *) inner_icmp)); + //It cannot be of a different type as ip6_icmp_to_icmp6_in_place succeeded + inner_icmp->type = (inner_icmp->type == ICMP6_echo_request) ? + ICMP4_echo_request : ICMP4_echo_reply; + csum = ip_csum_add_even (csum, *((u16 *) inner_icmp)); + inner_icmp->checksum = ip_csum_fold (csum); + inner_protocol = IP_PROTOCOL_ICMP; //Will be copied to ip6 later + inner_L4_checksum = &inner_icmp->checksum; + } + else + { + return -1; + } + + csum = *inner_L4_checksum; + csum = ip_csum_sub_even (csum, inner_ip6->src_address.as_u64[0]); + csum = ip_csum_sub_even (csum, inner_ip6->src_address.as_u64[1]); + csum = ip_csum_sub_even (csum, inner_ip6->dst_address.as_u64[0]); + csum = ip_csum_sub_even (csum, inner_ip6->dst_address.as_u64[1]); + + if ((rv = inner_fn (inner_ip6, inner_ip4, inner_ctx)) != 0) + return rv; + + inner_ip4->ip_version_and_header_length = + IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS; + inner_ip4->tos = ip6_translate_tos (inner_ip6); + inner_ip4->length = + u16_net_add (inner_ip6->payload_length, + sizeof (*ip4) + sizeof (*ip6) - inner_l4_offset); + inner_ip4->fragment_id = inner_frag_id; + inner_ip4->flags_and_fragment_offset = + clib_host_to_net_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS); + inner_ip4->ttl = inner_ip6->hop_limit; + inner_ip4->protocol = inner_protocol; + inner_ip4->checksum = ip4_header_checksum (inner_ip4); + + if (inner_ip4->protocol == IP_PROTOCOL_ICMP) + { + //Remove remainings of the pseudo-header in the csum + csum = + ip_csum_sub_even (csum, clib_host_to_net_u16 (IP_PROTOCOL_ICMP6)); + csum = + ip_csum_sub_even (csum, inner_ip4->length - sizeof (*inner_ip4)); + } + else + { + //Update to new pseudo-header + csum = ip_csum_add_even (csum, inner_ip4->src_address.as_u32); + csum = ip_csum_add_even (csum, inner_ip4->dst_address.as_u32); + } + *inner_L4_checksum = ip_csum_fold (csum); + + //Move up icmp header + ip4 = (ip4_header_t *) u8_ptr_add (inner_l4, -2 * sizeof (*ip4) - 8); + clib_memcpy (u8_ptr_add (inner_l4, -sizeof (*ip4) - 8), icmp, 8); + icmp = (icmp46_header_t *) u8_ptr_add (inner_l4, -sizeof (*ip4) - 8); + } + else + { + //Only one header to translate + ip4 = (ip4_header_t *) u8_ptr_add (ip6, sizeof (*ip6) - sizeof (*ip4)); + } + + vlib_buffer_advance (p, (u32) (((u8 *) ip4) - ((u8 *) ip6))); + + if ((rv = fn (ip6, ip4, ctx)) != 0) + return rv; + + ip4->ip_version_and_header_length = + IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS; + ip4->tos = ip6_translate_tos (ip6); + ip4->fragment_id = 0; + ip4->flags_and_fragment_offset = 0; + ip4->ttl = ip6->hop_limit; + ip4->protocol = IP_PROTOCOL_ICMP; + //TODO fix the length depending on offset length + ip4->length = u16_net_add (ip6->payload_length, + (inner_ip6 == + NULL) ? sizeof (*ip4) : (2 * sizeof (*ip4) - + sizeof (*ip6))); + ip4->checksum = ip4_header_checksum (ip4); + + //Recompute ICMP checksum + icmp->checksum = 0; + csum = + ip_incremental_checksum (0, icmp, + clib_net_to_host_u16 (ip4->length) - + sizeof (*ip4)); + icmp->checksum = ~ip_csum_fold (csum); + + return 0; +} + +/** + * @brief Translate IPv6 fragmented packet to IPv4. + * + * @param p Buffer to translate. + * @param fn The function to translate header. + * @param ctx A context passed in the header translate function. + * + * @returns 0 on success, non-zero value otherwise. + */ +always_inline int +ip6_to_ip4_fragmented (vlib_buffer_t * p, ip6_to_ip4_set_fn_t fn, void *ctx) +{ + ip6_header_t *ip6; + ip6_frag_hdr_t *frag; + ip4_header_t *ip4; + u16 frag_id; + u8 frag_more; + u16 frag_offset; + u8 l4_protocol; + u16 l4_offset; + int rv; + + ip6 = vlib_buffer_get_current (p); + + if (ip6_parse + (ip6, p->current_length, &l4_protocol, &l4_offset, &frag_offset)) + return -1; + + frag = (ip6_frag_hdr_t *) u8_ptr_add (ip6, frag_offset); + ip4 = (ip4_header_t *) u8_ptr_add (ip6, l4_offset - sizeof (*ip4)); + vlib_buffer_advance (p, l4_offset - sizeof (*ip4)); + + frag_id = frag_id_6to4 (frag->identification); + frag_more = ip6_frag_hdr_more (frag); + frag_offset = ip6_frag_hdr_offset (frag); + + if ((rv = fn (ip6, ip4, ctx)) != 0) + return rv; + + ip4->ip_version_and_header_length = + IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS; + ip4->tos = ip6_translate_tos (ip6); + ip4->length = u16_net_add (ip6->payload_length, + sizeof (*ip4) - l4_offset + sizeof (*ip6)); + ip4->fragment_id = frag_id; + ip4->flags_and_fragment_offset = + clib_host_to_net_u16 (frag_offset | + (frag_more ? IP4_HEADER_FLAG_MORE_FRAGMENTS : 0)); + ip4->ttl = ip6->hop_limit; + ip4->protocol = + (l4_protocol == IP_PROTOCOL_ICMP6) ? IP_PROTOCOL_ICMP : l4_protocol; + ip4->checksum = ip4_header_checksum (ip4); + + return 0; +} + +/** + * @brief Translate IPv6 UDP/TCP packet to IPv4. + * + * @param p Buffer to translate. + * @param fn The function to translate header. + * @param ctx A context passed in the header translate function. + * + * @returns 0 on success, non-zero value otherwise. + */ +always_inline int +ip6_to_ip4_tcp_udp (vlib_buffer_t * p, ip6_to_ip4_set_fn_t fn, void *ctx, + u8 udp_checksum) +{ + ip6_header_t *ip6; + u16 *checksum; + ip_csum_t csum; + ip4_header_t *ip4; + u16 fragment_id; + u16 flags; + u16 frag_offset; + u8 l4_protocol; + u16 l4_offset; + int rv; + + ip6 = vlib_buffer_get_current (p); + + if (ip6_parse + (ip6, p->current_length, &l4_protocol, &l4_offset, &frag_offset)) + return -1; + + if (l4_protocol == IP_PROTOCOL_TCP) + { + tcp_header_t *tcp = ip6_next_header (ip6); + checksum = &tcp->checksum; + } + else + { + udp_header_t *udp = ip6_next_header (ip6); + checksum = &udp->checksum; + //UDP checksum is optional over IPv4 + if (!udp_checksum) + goto no_csum; + } + + csum = ip_csum_sub_even (*checksum, ip6->src_address.as_u64[0]); + csum = ip_csum_sub_even (csum, ip6->src_address.as_u64[1]); + csum = ip_csum_sub_even (csum, ip6->dst_address.as_u64[0]); + csum = ip_csum_sub_even (csum, ip6->dst_address.as_u64[1]); + +no_csum: + ip4 = (ip4_header_t *) u8_ptr_add (ip6, l4_offset - sizeof (*ip4)); + + vlib_buffer_advance (p, l4_offset - sizeof (*ip4)); + + if (PREDICT_FALSE (frag_offset)) + { + //Only the first fragment + ip6_frag_hdr_t *hdr = (ip6_frag_hdr_t *) u8_ptr_add (ip6, frag_offset); + fragment_id = frag_id_6to4 (hdr->identification); + flags = clib_host_to_net_u16 (IP4_HEADER_FLAG_MORE_FRAGMENTS); + } + else + { + fragment_id = 0; + flags = 0; + } + + if ((rv = fn (ip6, ip4, ctx)) != 0) + return rv; + + ip4->ip_version_and_header_length = + IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS; + ip4->tos = ip6_translate_tos (ip6); + ip4->length = u16_net_add (ip6->payload_length, + sizeof (*ip4) + sizeof (*ip6) - l4_offset); + ip4->fragment_id = fragment_id; + ip4->flags_and_fragment_offset = flags; + ip4->ttl = ip6->hop_limit; + ip4->protocol = l4_protocol; + ip4->checksum = ip4_header_checksum (ip4); + + //UDP checksum is optional over IPv4 + if (!udp_checksum && l4_protocol == IP_PROTOCOL_UDP) + { + *checksum = 0; + } + else + { + csum = ip_csum_add_even (csum, ip4->dst_address.as_u32); + csum = ip_csum_add_even (csum, ip4->src_address.as_u32); + *checksum = ip_csum_fold (csum); + } + + return 0; +} + +#endif /* __included_ip6_to_ip4_h__ */ + +/* + * fd.io coding-style-patch-verification: ON + * + * Local Variables: + * eval: (c-set-style "gnu") + * End: + */ |