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 <netinet/in.h> 22 #include <netinet/ip.h> 23 #include <netinet/ip_icmp.h> 24 #include <netinet/udp.h> 25 #include <netinet/tcp.h> 26 #include <netinet/ip6.h> 27 #include <netinet/icmp6.h> 28 #include <linux/icmp.h> 29 #include <linux/if_tun.h> 30 31 #include "clatd.h" 32 33 #define MAX_TCP_HDR (15 * 4) // Data offset field is 4 bits and counts in 32-bit words. 34 35 // A clat_packet is an array of iovec structures representing a packet that we are translating. 36 // The CLAT_POS_XXX constants represent the array indices within the clat_packet that contain 37 // specific parts of the packet. The packet_* functions operate on all the packet segments past a 38 // given position. 39 typedef enum { 40 CLAT_POS_TUNHDR, CLAT_POS_IPHDR, CLAT_POS_FRAGHDR, CLAT_POS_TRANSPORTHDR, 41 CLAT_POS_ICMPERR_IPHDR, CLAT_POS_ICMPERR_FRAGHDR, CLAT_POS_ICMPERR_TRANSPORTHDR, 42 CLAT_POS_PAYLOAD, CLAT_POS_MAX 43 } clat_packet_index; 44 typedef struct iovec clat_packet[CLAT_POS_MAX]; 45 46 // Calculates the checksum over all the packet components starting from pos. 47 uint16_t packet_checksum(uint32_t checksum, clat_packet packet, clat_packet_index pos); 48 49 // Returns the total length of the packet components after pos. 50 uint16_t packet_length(clat_packet packet, clat_packet_index pos); 51 52 // Returns true iff the given IPv6 address is in the plat subnet. 53 int is_in_plat_subnet(const struct in6_addr *addr6); 54 55 // Functions to create tun, IPv4, and IPv6 headers. 56 void fill_tun_header(struct tun_pi *tun_header, uint16_t proto); 57 void fill_ip_header(struct iphdr *ip_targ, uint16_t payload_len, uint8_t protocol, 58 const struct ip6_hdr *old_header); 59 void fill_ip6_header(struct ip6_hdr *ip6, uint16_t payload_len, uint8_t protocol, 60 const struct iphdr *old_header); 61 62 // Translate and send packets. 63 void translate_packet(int fd, int to_ipv6, const uint8_t *packet, size_t packetsize); 64 65 // Translate IPv4 and IPv6 packets. 66 int ipv4_packet(clat_packet out, clat_packet_index pos, const uint8_t *packet, size_t len); 67 int ipv6_packet(clat_packet out, clat_packet_index pos, const uint8_t *packet, size_t len); 68 69 // Deal with fragmented packets. 70 size_t maybe_fill_frag_header(struct ip6_frag *frag_hdr, struct ip6_hdr *ip6_targ, 71 const struct iphdr *old_header); 72 uint8_t parse_frag_header(const struct ip6_frag *frag_hdr, struct iphdr *ip_targ); 73 74 // Deal with fragmented packets. 75 size_t maybe_fill_frag_header(struct ip6_frag *frag_hdr, struct ip6_hdr *ip6_targ, 76 const struct iphdr *old_header); 77 uint8_t parse_frag_header(const struct ip6_frag *frag_hdr, struct iphdr *ip_targ); 78 79 // Translate ICMP packets. 80 int icmp_to_icmp6(clat_packet out, clat_packet_index pos, const struct icmphdr *icmp, 81 uint32_t checksum, const uint8_t *payload, size_t payload_size); 82 int icmp6_to_icmp(clat_packet out, clat_packet_index pos, const struct icmp6_hdr *icmp6, 83 const uint8_t *payload, size_t payload_size); 84 85 // Translate generic IP packets. 86 int generic_packet(clat_packet out, clat_packet_index pos, const uint8_t *payload, size_t len); 87 88 // Translate TCP and UDP packets. 89 int tcp_packet(clat_packet out, clat_packet_index pos, const struct tcphdr *tcp, 90 uint32_t old_sum, uint32_t new_sum, size_t len); 91 int udp_packet(clat_packet out, clat_packet_index pos, const struct udphdr *udp, 92 uint32_t old_sum, uint32_t new_sum, size_t len); 93 94 int tcp_translate(clat_packet out, clat_packet_index pos, const struct tcphdr *tcp, 95 size_t header_size, uint32_t old_sum, uint32_t new_sum, 96 const uint8_t *payload, size_t payload_size); 97 int udp_translate(clat_packet out, clat_packet_index pos, const struct udphdr *udp, 98 uint32_t old_sum, uint32_t new_sum, 99 const uint8_t *payload, size_t payload_size); 100 101 #endif /* __TRANSLATE_H__ */ 102