add 203 codes
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179
Blatt02/A203/arp_packet.c
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179
Blatt02/A203/arp_packet.c
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@ -0,0 +1,179 @@
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#include "arp_packet.h"
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translation_table_entry translation_table[TB_L];
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int entry_length = 0;
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int entry_count = 0;
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int search_entry(translation_table_entry * entry, uint32_t ip, int * table_id){
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for(size_t i = 0 ; i < entry_length; i++){
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if(ip == translation_table[i].ar_spa){
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entry->ar_pro = translation_table[i].ar_pro;
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entry->ar_spa = translation_table[i].ar_spa;
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for(size_t j = 0 ; j < MAC_A_S ; j++){
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entry->ar_sha[j] = translation_table[i].ar_sha[j];
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}
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*table_id = i;
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translation_table[i].count = entry_count;
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entry_count++;
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return SUCCESS;
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}
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}
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return FAILED;
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}
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int update_entry(int table_id, uint8_t * mac_ares){
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if(table_id >= TB_L) {
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perror("table_id wrong");
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return FAILED;
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}
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for(size_t j = 0 ; j < MAC_A_S ; j++){
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translation_table[table_id].ar_sha[j] = mac_ares[j];
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}
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return SUCCESS;
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}
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int insert_entry(translation_table_entry * entry){
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int final_id = entry_length;
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if(entry_length == TB_L){
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int minn = 1<<31;
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int id = -1;
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for(size_t i = 0 ; i < entry_length ; i++){
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if(translation_table[i].count < minn){
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minn = translation_table[i].count;
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id = i;
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}
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}
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final_id = id;
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}
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translation_table[final_id].ar_pro = entry->ar_pro;
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translation_table[final_id].ar_spa = entry->ar_spa;
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for(size_t j = 0 ; j < MAC_A_S ; j++){
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translation_table[final_id].ar_sha[j] = entry->ar_sha[j];
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}
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translation_table[final_id].count = entry_count;
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entry_count++;
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return SUCCESS;
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}
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int parse_arp_packet(mac_hdr * hdr, pkt_data * pkt, uint8_t * buf, size_t size){
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size_t offset = 0;
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for(size_t i=offset;i<offset+MAC_A_S;i++) hdr->dest_ares[i-offset]=buf[i]; offset += MAC_A_S;
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for(size_t i=offset;i<offset+MAC_A_S;i++) hdr->send_ares[i-offset]=buf[i]; offset += MAC_A_S;
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hdr->pro_T =combine_uint8(buf[offset], buf[offset+1]); offset += 2;
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pkt->ar_hrd=combine_uint8(buf[offset], buf[offset+1]); offset += 2;
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pkt->ar_pro=combine_uint8(buf[offset], buf[offset+1]); offset += 2;
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pkt->ar_hln=buf[offset]; offset += 1;
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pkt->ar_pln=buf[offset]; offset += 1;
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pkt->ar_op =combine_uint8(buf[offset], buf[offset+1]); offset += 2;
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for(size_t i=offset;i<offset+MAC_A_S;i++) pkt->ar_sha[i-offset]=buf[i]; offset += MAC_A_S;
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pkt->ar_spa = combine_uint8_32(buf+offset); offset+=IP_A_S;
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for(size_t i=offset;i<offset+MAC_A_S;i++) pkt->ar_tha[i-offset]=buf[i]; offset += MAC_A_S;
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pkt->ar_tpa = combine_uint8_32(buf+offset); offset+=IP_A_S;
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}
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int receive_arp_packet(mac_hdr * hdr, pkt_data * pkt, uint8_t * buf, size_t size, uint8_t * local_ip, uint8_t * local_mac){
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uint32_t local_ip32 = combine_uint8_32(local_ip);
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if(size < 42) {
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printf("The packet is too short! This is not an ARP packet!\n");
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return FAILED;
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}
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parse_arp_packet(hdr, pkt, buf, size);
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if(hdr->pro_T != ETHER_T_ARP) {
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printf("The packet is not ARP packet!\n");
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return FAILED;
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}
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if(pkt->ar_hrd != ARES_HRD_ETHERNET){
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printf("The hardware is not Ethernet!\n");
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return FAILED;
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}
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if(pkt->ar_pro!= ARES_PRO_IP){
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printf("The protocol is not IPv4!\n");
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return FAILED;
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}
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int merge_flag = FALSE;
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int table_id = -1;
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translation_table_entry entry;
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if(search_entry(&entry, pkt->ar_spa, &table_id) == SUCCESS){
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update_entry(table_id, pkt->ar_sha);
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merge_flag = TRUE;
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}
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if(merge_flag == FALSE){
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entry.ar_pro = pkt->ar_pro;
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entry.ar_spa = pkt->ar_spa;
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for(size_t j = 0 ; j < MAC_A_S ; j++){
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entry.ar_sha[j] = pkt->ar_sha[j];
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}
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}
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if(pkt->ar_op==ARES_OP_REQ){
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printf("This is a request packet!\n");
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uint32_t tmp_ip;
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uint8_t tmp_mac[MAC_A_S];
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tmp_ip = pkt->ar_spa; pkt->ar_spa = pkt->ar_tpa; pkt->ar_tpa = tmp_ip;
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memcpy(tmp_mac, pkt->ar_sha, MAC_A_S); memcpy(pkt->ar_sha, pkt->ar_tha, MAC_A_S); memcpy(pkt->ar_tha, tmp_mac, MAC_A_S);
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memcpy(pkt->ar_sha, local_mac, MAC_A_S);
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pkt->ar_spa = local_ip32;
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pkt->ar_op = ARES_OP_REP;
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memcpy(tmp_mac, hdr->dest_ares, MAC_A_S); memcpy(hdr->dest_ares, hdr->send_ares, MAC_A_S); memcpy(hdr->send_ares, tmp_mac, MAC_A_S);
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memcpy(hdr->send_ares, local_mac, MAC_A_S);
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return SUCCESS;
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}
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printf("This is a response packet!\n");
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return SUCCESS;
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}
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int cv_uint16_to_uint8(uint8_t * tmp, uint16_t number){
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tmp[1] = number & 0x00FF;
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tmp[0] = (number >> 8 ) & 0x00FF;
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return SUCCESS;
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}
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int cv_arp_packet_to_uint8(uint8_t * resp_buffer, const pkt_data* pkt, const mac_hdr *hdr, size_t length){
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if( length < sizeof(pkt_data) + sizeof(mac_hdr) ) return FAILED;
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memcpy(resp_buffer, hdr->dest_ares, MAC_A_S); print_hex(resp_buffer, MAC_A_S); resp_buffer += MAC_A_S;
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memcpy(resp_buffer, hdr->send_ares, MAC_A_S); print_hex(resp_buffer, MAC_A_S); resp_buffer += MAC_A_S;
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uint8_t tmp[2];
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cv_uint16_to_uint8(tmp, hdr->pro_T);
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memcpy(resp_buffer, tmp, sizeof(uint16_t)); print_hex(resp_buffer, sizeof(uint16_t)); resp_buffer += sizeof(uint16_t);
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cv_uint16_to_uint8(tmp, pkt->ar_hrd);
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memcpy(resp_buffer, tmp, sizeof(uint16_t)); print_hex(resp_buffer, sizeof(uint16_t)); resp_buffer += sizeof(uint16_t);
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cv_uint16_to_uint8(tmp, pkt->ar_pro);
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memcpy(resp_buffer, tmp, sizeof(uint16_t)); print_hex(resp_buffer, sizeof(uint16_t)); resp_buffer += sizeof(uint16_t);
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uint16_t hln_pln = (pkt->ar_hln << 8) | (pkt->ar_pln);
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cv_uint16_to_uint8(tmp, hln_pln);
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memcpy(resp_buffer, tmp, sizeof(uint16_t)); print_hex(resp_buffer, sizeof(uint16_t)); resp_buffer += sizeof(uint16_t);
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cv_uint16_to_uint8(tmp, pkt->ar_op);
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memcpy(resp_buffer, tmp, sizeof(uint16_t)); print_hex(resp_buffer, sizeof(uint16_t)); resp_buffer += sizeof(uint16_t);
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memcpy(resp_buffer, pkt->ar_sha, MAC_A_S); print_hex(resp_buffer, MAC_A_S); resp_buffer += MAC_A_S;
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uint8_t tmp_ip[4];
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for(size_t i = 0 ; i < 4 ; i++)
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tmp_ip[3-i] = ((pkt->ar_spa >> i * 8) & 0xFF);
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memcpy(resp_buffer, tmp_ip, IP_A_S); print_hex(resp_buffer, IP_A_S); resp_buffer += IP_A_S;
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memcpy(resp_buffer, pkt->ar_tha, MAC_A_S); print_hex(resp_buffer, MAC_A_S); resp_buffer += MAC_A_S;
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for(size_t i = 0 ; i < 4 ; i++)
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tmp_ip[3-i] = ((pkt->ar_tpa >> i * 8) & 0xFF);
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memcpy(resp_buffer, tmp_ip, IP_A_S); print_hex(resp_buffer, IP_A_S); resp_buffer += IP_A_S;
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return SUCCESS;
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}
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int send_arp_response(int tun_fd, uint8_t * resp_buffer, size_t length, const pkt_data * pkt, const mac_hdr * hdr){
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if(cv_arp_packet_to_uint8(resp_buffer, pkt, hdr, length) == FAILED) return FAILED;
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ssize_t nwrite = write(tun_fd, resp_buffer, length);
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if(nwrite < 0) return FAILED;
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return SUCCESS;
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}
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43
Blatt02/A203/arp_packet.h
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43
Blatt02/A203/arp_packet.h
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#ifndef ARP_PACKET_H
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#define ARP_PACKET_H
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#include <assert.h>
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#include <arpa/inet.h>
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#include <sys/ioctl.h>
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#include <net/if.h>
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#include <linux/if_tun.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdint.h>
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#include "arp_packet_st.h"
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#include "util.h"
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#define IP_A_S 4
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#define OP_A_S 2
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#define SUCCESS 0
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#define FAILED -1
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#define UNEQUAL 1
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#define ARES_OP_REQ 0x0001
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#define ARES_OP_REP 0x0002
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#define ARES_HRD_ETHERNET 0x0001
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#define ETHER_T_ARP 0x0806
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#define ARES_PRO_IP 0x0800
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#define TB_L 100
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int parse_arp_packet(mac_hdr * hdr, pkt_data * pkt, uint8_t * buf, size_t size);
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int receive_arp_packet(mac_hdr * hdr, pkt_data * pkt, uint8_t * buf, size_t size, uint8_t * local_ip, uint8_t * local_mac);
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int send_arp_response(int tun_fd, uint8_t * resp_buffer, size_t length, const pkt_data * pkt, const mac_hdr * hdr);
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#endif
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36
Blatt02/A203/arp_packet_st.h
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36
Blatt02/A203/arp_packet_st.h
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#ifndef ARP_PACKET_ST_H
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#define ARP_PACKET_ST_H
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#define MAC_A_S 6
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#include<stdint.h>
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#include<stddef.h>
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typedef struct{
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uint8_t dest_ares[MAC_A_S];
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uint8_t send_ares[MAC_A_S];
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uint16_t pro_T;
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}mac_hdr;
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typedef struct{
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uint16_t ar_hrd;
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uint16_t ar_pro;
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uint8_t ar_hln;
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uint8_t ar_pln;
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uint16_t ar_op;
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uint8_t ar_sha[MAC_A_S];
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uint32_t ar_spa;
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uint8_t ar_tha[MAC_A_S];
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uint32_t ar_tpa;
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}pkt_data;
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typedef struct{
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uint16_t ar_pro;
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uint32_t ar_spa;
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uint8_t ar_sha[MAC_A_S];
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int count;
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}translation_table_entry;
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#endif
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108
Blatt02/A203/tuntap.c
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108
Blatt02/A203/tuntap.c
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#include "arp_packet.h"
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#define CLEAR(x) memset(&(x), 0x00, sizeof(x))
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#define IFNAME "tap0"
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// #define IFNAME "tun0"
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#define BUFLEN 1600
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static int tun_alloc(char *dev)
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{
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struct ifreq ifr;
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int fd, err;
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if( (fd = open("/dev/net/tun", O_RDWR)) < 0 ) {
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perror("Cannot open TUN/TAP dev\n"
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"Make sure one exists with "
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"'$ mknod /dev/net/tun c 10 200'");
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exit(1);
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}
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CLEAR(ifr);
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/* Flags: IFF_TUN - TUN device (no Ethernet headers)
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* IFF_TAP - TAP device
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*
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* IFF_NO_PI - Do not provide packet information
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*/
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ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
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if( *dev ) {
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strncpy(ifr.ifr_name, dev, IFNAMSIZ);
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}
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if( (err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ){
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perror("ERR: Could not ioctl tun");
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close(fd);
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return err;
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}
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strcpy(dev, ifr.ifr_name);
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return fd;
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}
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// int check_ip(uint8_t * ip, int length){
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// if(length != TARGET_IP_A_S) return UNEQUAL;
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// int8_t pc2[4]={10,5,1,2};
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// for(size_t i = 0 ; i < length ; i++)
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// printf("%X, %X \n", ip[i], pc2[i]);
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//
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// for(size_t i = 0 ; i < length ; i++)
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// if(ip[i]!=pc2[i]) return FAILED;
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// return SUCCESS;
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//}
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//
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int main (int argc, char *argv[]){
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char dev[IFNAMSIZ];
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int tun_fd;
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uint8_t local_ip[4] = {10, 5, 1, 10};
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uint8_t local_mac[6] = {0xD6,0x74,0x45,0xDC,0x5A,0xCD};
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if (argc > 1) {
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assert(strlen(argv[1]) < IFNAMSIZ);
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strcpy(dev, argv[1]);
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} else {
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strcpy(dev, IFNAME);
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}
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printf("device name: %s\n", dev);
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tun_fd = tun_alloc(dev);
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int running = 1;
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uint8_t buf[BUFLEN];
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while (running) {
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int nread;
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if ((nread = read(tun_fd, buf, BUFLEN)) < 0) {
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perror("ERR: Read from tun_fd");
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break;
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}
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// buf[nread] = '\0';
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printf("buf :");
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print_hex(buf, nread);
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mac_hdr hdr;
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pkt_data pkt;
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if(parse_arp_packet(&hdr, &pkt, buf, nread) == FAILED){
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perror("ERR: Cannot parse the packet");
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}
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if(receive_arp_packet(&hdr, &pkt, buf, nread, local_ip, local_mac) == FAILED){
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perror("ERR: Cannot process the packet");
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}
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if(send_arp_response(tun_fd, buf, nread, &pkt, &hdr) == FAILED){
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perror("ERR: Cannot send the response");
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}
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printf("Read %d bytes from device %s\n\n", nread, dev);
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}
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close(tun_fd);
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return EXIT_SUCCESS;
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}
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46
Blatt02/A203/util.c
Normal file
46
Blatt02/A203/util.c
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#include "util.h"
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void print_hex(uint8_t * array, size_t size){
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for (size_t i = 0 ; i < size; i++){
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uint8_t high = (array[i] >> 4) & 0x0F;
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uint8_t low = array[i] & 0x0F;
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printf("%X", high);
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printf("%X ", low);
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}
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printf("\n");
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}
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void print_u16_hex(uint16_t number){
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uint8_t tmp_a[2];
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tmp_a[0] = (number >> 8) & 0x00FF;
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tmp_a[1] = number & 0x00FF;
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print_hex(tmp_a, 2);
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return;
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}
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void print_u8_hex(uint8_t number){
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printf("%X", (number >> 4) & 0x0F);
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printf("%X", number & 0x0F);
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printf("\n");
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}
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// void print_packet_info(arp_packet_t * packet){
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// printf("destination: "); print_hex(packet->destination, DST_S);
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// printf("source: "); print_hex(packet->source, SRC_S);
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//
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// printf("hardware type: "); print_u16_hex(packet->hrd_t);
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// printf("protocal type: "); print_u16_hex(packet->pro_t);
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// printf("hardware size: "); print_u8_hex(packet->hrd_s);
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// printf("protocal size: "); print_u8_hex(packet->pro_s);
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// printf("op type: "); print_u16_hex(packet->op);
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//
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// printf("sender mac address: "); print_hex(packet->sender_mac_a, SENDER_MAC_A_S);
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// printf("sender ip address: "); print_hex(packet->sender_ip_a, SENDER_IP_A_S);
|
||||
// printf("target mac address: "); print_hex(packet->target_mac_a, TARGET_MAC_A_S);
|
||||
// printf("target ip address: "); print_hex(packet->target_ip_a, TARGET_IP_A_S);
|
||||
// }
|
||||
|
||||
uint16_t combine_uint8(uint8_t high, uint8_t low){
|
||||
return (high << 8 ) | low;
|
||||
}
|
||||
uint32_t combine_uint8_32(uint8_t * arr){
|
||||
return (arr[0] << 24 ) | (arr[1] << 16) | (arr[2] << 8) | (arr[3]);
|
||||
}
|
||||
16
Blatt02/A203/util.h
Normal file
16
Blatt02/A203/util.h
Normal file
@ -0,0 +1,16 @@
|
||||
#ifndef UTIL_H
|
||||
#define UTIL_H
|
||||
|
||||
#include <stdio.h>
|
||||
#include "arp_packet_st.h"
|
||||
|
||||
#define TRUE 1
|
||||
#define FALSE 0
|
||||
|
||||
void print_hex(uint8_t * array, size_t size);
|
||||
void print_u16_hex(uint16_t number);
|
||||
void print_u8_hex(uint8_t number);
|
||||
uint16_t combine_uint8(uint8_t high, uint8_t low);
|
||||
uint32_t combine_uint8_32(uint8_t * arr);
|
||||
|
||||
#endif
|
||||
Loading…
Reference in New Issue
Block a user