1 /* 2 * Copyright 2011 Daniel Drown 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 * 16 * translate.h - translate from one version of ip to another 17 */ 18 #ifndef __TRANSLATE_H__ 19 #define __TRANSLATE_H__ 20 21 #include <linux/if_tun.h> 22 23 #define MAX_TCP_HDR (15 * 4) // Data offset field is 4 bits and counts in 32-bit words. 24 25 // A clat_packet is an array of iovec structures representing a packet that we are translating. 26 // The CLAT_POS_XXX constants represent the array indices within the clat_packet that contain 27 // specific parts of the packet. The packet_* functions operate on all the packet segments past a 28 // given position. 29 enum clat_packet_index { CLAT_POS_TUNHDR, CLAT_POS_IPHDR, CLAT_POS_TRANSPORTHDR, 30 CLAT_POS_ICMPERR_IPHDR, CLAT_POS_ICMPERR_TRANSPORTHDR, 31 CLAT_POS_PAYLOAD, CLAT_POS_MAX }; 32 typedef struct iovec clat_packet[CLAT_POS_MAX]; 33 34 // Calculates the checksum over all the packet components starting from pos. 35 uint16_t packet_checksum(uint32_t checksum, clat_packet packet, int pos); 36 37 // Returns the total length of the packet components after pos. 38 uint16_t packet_length(clat_packet packet, int pos); 39 40 // Returns true iff the given IPv6 address is in the plat subnet. 41 int is_in_plat_subnet(const struct in6_addr *addr6); 42 43 // Functions to create tun, IPv4, and IPv6 headers. 44 void fill_tun_header(struct tun_pi *tun_header, uint16_t proto); 45 void fill_ip_header(struct iphdr *ip_targ, uint16_t payload_len, uint8_t protocol, 46 const struct ip6_hdr *old_header); 47 void fill_ip6_header(struct ip6_hdr *ip6, uint16_t payload_len, uint8_t protocol, 48 const struct iphdr *old_header); 49 50 // Translate ICMP packets. 51 int icmp_to_icmp6(clat_packet out, int pos, const struct icmphdr *icmp, uint32_t checksum, 52 const char *payload, size_t payload_size); 53 int icmp6_to_icmp(clat_packet out, int pos, const struct icmp6_hdr *icmp6, uint32_t checksum, 54 const char *payload, size_t payload_size); 55 56 // Translate TCP and UDP packets. 57 int tcp_packet(clat_packet out, int pos, const struct tcphdr *tcp, uint32_t checksum, size_t len); 58 int udp_packet(clat_packet out, int pos, const struct udphdr *udp, uint32_t checksum, size_t len); 59 60 int tcp_translate(clat_packet out, int pos, const struct tcphdr *tcp, size_t header_size, 61 uint32_t checksum, const char *payload, size_t payload_size); 62 int udp_translate(clat_packet out, int pos, const struct udphdr *udp, uint32_t checksum, 63 const char *payload, size_t payload_size); 64 65 #endif /* __TRANSLATE_H__ */ 66
