mirror of
https://code.semirocket.science/wrapsix
synced 2024-11-10 00:01:01 +02:00
Completed TCP with fragmenting in IPv6 packets
Modified TCP in 6to4 way to use special IP address
This commit is contained in:
xHire
parent
32e7d6459b
commit
e7d8a4c1dd
@ -39,10 +39,47 @@ void send_there(struct in_addr ip4_addr, unsigned char ttl, unsigned int type, u
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close(sock);
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}
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void send_raw_ipv4(struct in_addr ip4_addr, unsigned char *packet, int packet_size)
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{
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struct sockaddr_in socket_address;
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unsigned char on = 1;
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int sock;
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/* prepare data for RAW socket */
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socket_address.sin_family = AF_INET;
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socket_address.sin_port = htons(0);
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memcpy(&socket_address.sin_addr.s_addr, &ip4_addr, sizeof(struct in_addr));
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/* initialize raw socket */
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if ((sock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) == -1) {
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fprintf(stderr, "Couldn't open RAW socket.\n");
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perror("socket()");
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exit(EXIT_FAILURE);
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}
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/* we will provide our own IPv4 header */
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if (setsockopt(sock, IPPROTO_IP, IP_HDRINCL, &on, sizeof(on)) == -1) {
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fprintf(stderr, "Couldn't apply the socket settings.\n");
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perror("setsockopt()");
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exit(EXIT_FAILURE);
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}
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/* send the packet */
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if (sendto(sock, packet, packet_size, 0, (struct sockaddr *) &socket_address, sizeof(struct sockaddr)) != packet_size) {
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fprintf(stderr, "Couldn't send a RAW packet.\n");
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perror("sendto()");
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exit(EXIT_FAILURE);
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}
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/* close the socket */
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close(sock);
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}
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void send_raw(unsigned char *packet, int packet_size)
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{
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struct sockaddr_ll socket_address; /* target address */
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struct ifreq ifr; /* interface */
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struct sockaddr_ll socket_address;
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struct ifreq ifr;
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int sock;
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@ -72,9 +109,9 @@ void send_raw(unsigned char *packet, int packet_size)
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exit(EXIT_FAILURE);
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}
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/* send the NDP packet */
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/* send the packet */
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if (sendto(sock, packet, packet_size, 0, (struct sockaddr *) &socket_address, sizeof(struct sockaddr_ll)) != packet_size) {
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fprintf(stderr, " Error: Couldn't send an IPv6 packet.\n");
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fprintf(stderr, "Couldn't send a RAW packet.\n");
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perror("sendto()");
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exit(EXIT_FAILURE);
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}
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@ -5,8 +5,6 @@
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#include "translate_ip.h"
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#include "storage.h"
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struct in6_addr ip6addr_wrapsix;
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void process_packet(u_char *args, const struct pcap_pkthdr *header, const u_char *packet)
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{
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const struct s_ethernet *eth; /* the ethernet header */
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@ -30,7 +28,7 @@ void process_packet(u_char *args, const struct pcap_pkthdr *header, const u_char
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process_arp(eth, payload);
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break;
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default:
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printf("\n IP: unknown (%d/0x%x)\n", htons(eth->type), htons(eth->type));
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printf("\n Proto: unknown (%d/0x%x)\n", htons(eth->type), htons(eth->type));
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break;
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}
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}
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@ -55,7 +53,7 @@ void process_packet4(const struct s_ethernet *eth, const unsigned char *packet)
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printf(" To: %s\n", inet_ntoa(ip->ip_dest));
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/* check if this packet is ours */
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if (memcmp(dev_ip, &ip->ip_dest, 4)) {
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if (memcmp(&ip4addr_wrapsix, &ip->ip_dest, 4)) {
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printf("==> This packet is not ours! <==\n");
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return;
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}
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@ -82,12 +80,19 @@ void process_packet4(const struct s_ethernet *eth, const unsigned char *packet)
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void process_tcp4(const struct s_ethernet *eth_hdr, struct s_ip4 *ip_hdr, const unsigned char *payload, unsigned short data_size)
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{
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struct s_tcp *tcp;
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struct ip6_hdr *ip;
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struct s_ethernet *eth;
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struct ip6_hdr *ip;
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struct s_ip6_fragment *ip_frag;
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struct s_tcp *tcp;
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unsigned char *packet;
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unsigned int packet_size;
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unsigned short packet_size;
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unsigned char do_frag = 0;
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unsigned char last_frag = 0;
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unsigned short frag_size = 1514 - SIZE_ETHERNET - SIZE_IP6 - 8 - 4; /* 4 for alignment */
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unsigned short data_frag_size;
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unsigned char *data_offset;
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unsigned short data_frag_offset = 0;
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struct stg_conn_tup *ent = NULL;
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struct stg_conn_tup *ent_tmp;
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@ -121,11 +126,42 @@ void process_tcp4(const struct s_ethernet *eth_hdr, struct s_ip4 *ip_hdr, const
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printf(" IP-from: %s\n", inet_ntoa(ip_hdr->ip_src));
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return;
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}
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ent->packet_num++;
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/* set the checksum to zero */
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tcp->checksum = 0x0;
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/* compute the TCP checksum */
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tcp->checksum = checksum_ipv6(ipaddr_4to6(ent->addr_to), ent->addr_from, data_size, IPPROTO_TCP, (unsigned char *) payload);
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printf(" Checksum: 0x%x\n", tcp->checksum);
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/* handle fragmentation */
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packet_size = data_size + SIZE_ETHERNET + SIZE_IP6;
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packet = (unsigned char *) malloc(packet_size);
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if (packet == NULL) {
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/* check if the packet is not too big => fragment */
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if (packet_size > 1514) {
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do_frag = 1;
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printf("...fragmenting: %d B\n", packet_size);
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}
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/* send so many packets how many is needed */
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while (data_size) {
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if (do_frag && data_size > frag_size) {
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packet_size = 1514 - 4;
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data_frag_size = frag_size;
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}
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else if (do_frag) {
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packet_size = SIZE_ETHERNET + SIZE_IP6 + 8 + data_size;
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data_frag_size = data_size;
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last_frag = 1;
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printf("...last fragment\n");
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}
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else {
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data_frag_size = data_size;
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printf("...not fragmenting: %d B\n", packet_size);
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}
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if ((packet = (unsigned char *) malloc(packet_size)) == NULL) {
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fprintf(stderr, "Fatal error! Lack of free memory!\n");
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exit(EXIT_FAILURE);
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}
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@ -136,6 +172,29 @@ void process_tcp4(const struct s_ethernet *eth_hdr, struct s_ip4 *ip_hdr, const
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/* parse the packet into structures */
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eth = (struct s_ethernet *) packet;
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ip = (struct ip6_hdr *) (packet + SIZE_ETHERNET);
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if (do_frag) {
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if ((ip_frag = (struct s_ip6_fragment *) malloc(sizeof(struct s_ip6_fragment))) == NULL) {
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fprintf(stderr, "Fatal error! Lack of free memory!\n");
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exit(EXIT_FAILURE);
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}
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data_offset = (unsigned char *) (packet + SIZE_ETHERNET + SIZE_IP6 + sizeof(struct s_ip6_fragment));
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memset(ip_frag, 0x0, sizeof(struct s_ip6_fragment));
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ip_frag->next_header = IPPROTO_TCP;
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ip_frag->zeros = 0x0;
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ip_frag->id = htonl(ent->port + ent->packet_num);
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ip_frag->offset_flag = (htons((data_frag_offset / 8) << 3));
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if (!last_frag) {
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ip_frag->offset_flag |= htons(0x1);
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}
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// copy it & free it
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memcpy(packet + SIZE_ETHERNET + SIZE_IP6, ip_frag, sizeof(struct s_ip6_fragment));
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free(ip_frag);
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}
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else {
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data_offset = (unsigned char *) (ip + SIZE_IP6);
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}
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/* assemble the ethernet header */
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memcpy(ð->src, mac, sizeof(struct s_mac_addr));
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@ -143,34 +202,47 @@ void process_tcp4(const struct s_ethernet *eth_hdr, struct s_ip4 *ip_hdr, const
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eth->type = htons(ETHERTYPE_IPV6);
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/* assemble the IPv6 header */
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if (do_frag) {
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build_ip6_hdr(ip, /* ip6_hdr structure */
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ipaddr_4to6(ent->addr_to), /* source address */
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ent->addr_from, /* destination address */
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data_size, /* payload length */
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data_frag_size + 8, /* payload length + fragment header */
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IPPROTO_FRAGMENT, /* protocol */
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ip_hdr->ttl); /* ttl */
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}
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else {
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build_ip6_hdr(ip, /* ip6_hdr structure */
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ipaddr_4to6(ent->addr_to), /* source address */
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ent->addr_from, /* destination address */
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data_frag_size, /* payload length */
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IPPROTO_TCP, /* protocol */
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ip_hdr->ttl); /* ttl */
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}
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char ip6addr[INET6_ADDRSTRLEN];
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inet_ntop(AF_INET6, &ent->addr_from, ip6addr, sizeof(ip6addr));
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printf(" Send to: %s\n", ip6addr);
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/* set the checksum to zero */
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tcp->checksum = 0x0;
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/* copy data into the packet */
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memcpy(packet + SIZE_ETHERNET + SIZE_IP6, payload, data_size);
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/* compute the TCP checksum */
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tcp->checksum = checksum_ipv6(ip->ip6_src, ip->ip6_dst, data_size, ip->ip6_nxt, (unsigned char *) (packet + SIZE_ETHERNET + SIZE_IP6));
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/* return the checksum into the packet */
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memcpy(packet + SIZE_ETHERNET + SIZE_IP6, tcp, sizeof(struct s_tcp));
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if (!do_frag) {
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memcpy(packet + SIZE_ETHERNET + SIZE_IP6, payload, data_frag_size);
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}
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else {
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memcpy(packet + SIZE_ETHERNET + SIZE_IP6 + sizeof(struct s_ip6_fragment), (unsigned char *) (payload + data_frag_offset), data_frag_size);
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}
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/* send the wrapped packet back */
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send_raw(packet, packet_size);
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/* free allocated memory */
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free(packet);
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packet = NULL;
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eth = NULL;
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ip = NULL;
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data_size -= data_frag_size;
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data_frag_offset += data_frag_size;
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}
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}
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void process_udp4(const struct s_ethernet *eth_hdr, struct s_ip4 *ip_hdr, const unsigned char *payload, unsigned short data_size)
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@ -471,8 +543,7 @@ void process_packet6(const struct s_ethernet *eth, const unsigned char *packet)
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inet_ntop(AF_INET6, &ip->ip_dest, ip6addr, sizeof(ip6addr));
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printf(" To: %s\n", ip6addr);
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/* check if this packet is ours - partially hardcoded for now */
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inet_pton(AF_INET6, "fc00:1::", &ip6addr_wrapsix);
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/* check if this packet is ours */
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inet_pton(AF_INET6, "ff02::1:ff00:0", &ip6addr_ndp_multicast);
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/* check for our prefix || NDP */
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if (memcmp(&ip6addr_wrapsix, &ip->ip_dest, 12) != 0
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@ -501,18 +572,20 @@ void process_packet6(const struct s_ethernet *eth, const unsigned char *packet)
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}
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}
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void process_tcp6(const struct s_ethernet *eth, struct s_ip6 *ip, const unsigned char *payload)
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void process_tcp6(const struct s_ethernet *eth_hdr, struct s_ip6 *ip_hdr, const unsigned char *payload)
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{
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struct s_ip4 *ip;
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struct s_tcp *tcp;
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struct in_addr ip4_addr_src, ip4_addr_dest;
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struct in_addr ip4_addr;
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unsigned char *tcp_packet;
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unsigned char *packet;
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unsigned char ent_save = 0;
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struct stg_conn_tup *ent;
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struct stg_conn_tup *ent_tmp;
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unsigned short packet_size = htons(ip->len);
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unsigned short data_size = htons(ip_hdr->len);
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unsigned short packet_size = sizeof(struct s_ip4) + data_size;
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/* define TCP header */
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tcp = (struct s_tcp *) payload;
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@ -539,9 +612,10 @@ void process_tcp6(const struct s_ethernet *eth, struct s_ip6 *ip, const unsigned
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/* save the connection */
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ent = (struct stg_conn_tup *) malloc(sizeof(struct stg_conn_tup));
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ent->port = htons(tcp->port_src);
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ent->addr_from = ip->ip_src;
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ent->mac = eth->src;
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ent->addr_from = ip_hdr->ip_src;
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ent->mac = eth_hdr->src;
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time(&ent->time);
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ent->packet_num = 0;
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memset(&ent->addr_to, 0x0, sizeof(struct in_addr));
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ent_save = 1;
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}
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@ -553,36 +627,43 @@ void process_tcp6(const struct s_ethernet *eth, struct s_ip6 *ip, const unsigned
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}
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/* decide where to send this TCP */
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ip4_addr_dest = ipaddr_6to4(ip->ip_dest);
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printf(" Send to: %s\n", inet_ntoa(ip4_addr_dest));
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ip4_addr = ipaddr_6to4(ip_hdr->ip_dest);
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printf(" Send to: %s\n", inet_ntoa(ip4_addr));
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/* create one big TCP packet */
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tcp_packet = (unsigned char *) malloc(packet_size);
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packet = (unsigned char *) malloc(packet_size);
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if (tcp_packet == NULL) {
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if (packet == NULL) {
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fprintf(stderr, "Fatal error! Lack of free memory!\n");
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exit(EXIT_FAILURE);
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}
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/* first set the checksum to zero */
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tcp->checksum = 0x0;
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/* copy data into the packet */
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memcpy(tcp_packet, payload, packet_size);
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/* assemble IPv4 header */
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ip = (struct s_ip4 *) packet;
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ip->ver_ihl = 0x45;
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ip->tos = 0x0;
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ip->pckt_len = htons(packet_size);
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ip->flags_offset = htons(0x4000);
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ip->id = 0x0;
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ip->ttl = ip_hdr->hop_limit;
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ip->proto = IPPROTO_TCP;
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ip->checksum = 0x0; /* it is computed automatically */
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ip->ip_src = ip4addr_wrapsix;
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ip->ip_dest = ip4_addr;
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/* compute the checksum */
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memcpy(&ip4_addr_src, dev_ip, sizeof(struct in_addr));
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tcp->checksum = checksum_ipv4(ip4_addr_src, ip4_addr_dest, packet_size, IPPROTO_TCP, tcp_packet);
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tcp->checksum = 0x0;
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tcp->checksum = checksum_ipv4(ip4addr_wrapsix, ip4_addr, data_size, IPPROTO_TCP, (unsigned char *) payload);
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/* copy this structure again - because of the checksum */
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memcpy(tcp_packet, tcp, sizeof(struct s_tcp));
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/* copy data into the packet */
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memcpy(packet + sizeof(struct s_ip4), payload, data_size);
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/* send */
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send_there(ip4_addr_dest, ip->hop_limit, IPPROTO_TCP, tcp_packet, packet_size);
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send_raw_ipv4(ip->ip_dest, packet, packet_size);
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/* save the connection */
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if (ent_save == 1) {
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ent->addr_to = ip4_addr_dest;
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ent->addr_to = ip4_addr;
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jsw_rbinsert(stg_conn_tcp, ent);
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printf(" Conn #: %d\n", jsw_rbsize(stg_conn_tcp));
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/* the entry is not needed now and should be freed */
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@ -590,8 +671,8 @@ void process_tcp6(const struct s_ethernet *eth, struct s_ip6 *ip, const unsigned
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}
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/* free allocated memory */
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free(tcp_packet);
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tcp_packet = NULL;
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free(packet);
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packet = NULL;
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}
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void process_udp6(const struct s_ethernet *eth, struct s_ip6 *ip, const unsigned char *payload)
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@ -16,6 +16,7 @@ struct stg_conn_tup {
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struct in6_addr addr_from;
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struct s_mac_addr mac;
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time_t time;
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unsigned int packet_num;
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};
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struct stg_conn_icmp {
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@ -5,6 +5,7 @@ struct s_mac_addr *mac; /* MAC address of the device */
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char *dev; /* capture device name */
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int dev_index; /* capture device index */
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struct in_addr *dev_ip; /* IP address associated with the device */
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struct in6_addr ip6addr_wrapsix; /* IPv6 prefix of WrapSix addresses */
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struct in_addr ip4addr_wrapsix; /* IPv4 address for WrapSix */
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/* storage trees */
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@ -70,8 +71,9 @@ int main(int argc, char **argv)
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/* get index of the device */
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dev_index = get_dev_index(dev);
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/* set the WrapSix IPv4 address */
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/* set the WrapSix addresses */
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inet_aton("10.0.0.111", &ip4addr_wrapsix);
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inet_pton(AF_INET6, "fc00:1::", &ip6addr_wrapsix);
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/* compile the filter expression */
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if (pcap_compile(handle, &fp, filter_exp, 0, 0) == -1) {
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@ -97,6 +97,14 @@ struct s_ip6_pseudo {
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unsigned char next_header; /* 8 b; next header */
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};
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/* IPv6 fragment header */
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struct s_ip6_fragment {
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unsigned char next_header; /* 8 b; next header */
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unsigned char zeros; /* 8 b; reserved */
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unsigned short offset_flag; /* 16 b; 13 b - data offset, 2 b - reserved, 1 b - flag */
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unsigned int id; /* 32 b; identification */
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};
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/* TCP structure */
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struct s_tcp {
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unsigned short port_src; /* 16 b; source port */
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@ -187,13 +195,14 @@ void process_icmp4(const struct s_ethernet *eth_hdr, struct s_ip4 *ip_hdr, const
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void process_arp(const struct s_ethernet *eth_hdr, const unsigned char *arp_packet);
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void process_packet6(const struct s_ethernet *eth, const unsigned char *packet);
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void process_tcp6(const struct s_ethernet *eth, struct s_ip6 *ip, const unsigned char *payload);
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void process_tcp6(const struct s_ethernet *eth_hdr, struct s_ip6 *ip_hdr, const unsigned char *payload);
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void process_udp6(const struct s_ethernet *eth, struct s_ip6 *ip, const unsigned char *payload);
|
||||
void process_icmp6(const struct s_ethernet *eth, struct s_ip6 *ip, const unsigned char *payload);
|
||||
void process_ndp(const struct s_ethernet *eth_hdr, struct s_ip6 *ip_hdr, unsigned char *icmp_data);
|
||||
|
||||
void send_there(struct in_addr ip4_addr, unsigned char ttl, unsigned int type, unsigned char *payload, unsigned int paylen);
|
||||
void send_raw(unsigned char *packet, int packet_size);
|
||||
void send_raw_ipv4(struct in_addr ip4_addr, unsigned char *packet, int packet_size);
|
||||
|
||||
unsigned short checksum(const void *_buf, int len);
|
||||
unsigned short checksum_ipv4(struct in_addr ip_src, struct in_addr ip_dest, unsigned short length, unsigned char proto, unsigned char *data);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user