NAT64: Move IPv6-IPv4 virtual reassembly code from MAP-T to common library (VPP-708)
Change-Id: I9ad636f80bf109ffac9ca1b6d80d5f2c31f2076a
Signed-off-by: Matus Fabian <matfabia@cisco.com>
diff --git a/src/vnet/ip/ip6_to_ip4.h b/src/vnet/ip/ip6_to_ip4.h
new file mode 100644
index 0000000..f5d5688
--- /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:
+ */