diff options
| -rw-r--r-- | Makefile | 2 | ||||
| -rw-r--r-- | main.c | 220 | ||||
| -rw-r--r-- | udp.c | 47 |
3 files changed, 195 insertions, 74 deletions
@@ -7,4 +7,4 @@ dist-clean: rm -f mactelnet mactelnet: main.c udp.h udp.c - gcc -o mactelnet main.c udp.c + gcc -g -o mactelnet main.c udp.c @@ -3,32 +3,149 @@ #include <netinet/in.h> #include <sys/types.h> #include <sys/socket.h> +#include <string.h> #include <linux/if_ether.h> #include "udp.h" -struct mactelnet_cli_hdr { +#define DEBUG 0 + +#define MT_PTYPE_SESSIONSTART 0 +#define MT_PTYPE_DATA 1 +#define MT_PTYPE_ACK 2 +#define MT_PTYPE_END 255 + +#define MT_CPTYPE_BEGINAUTH 0 +#define MT_CPTYPE_ENCRYPTIONKEY 1 +#define MT_CPTYPE_PASSWORD 2 +#define MT_CPTYPE_USERNAME 3 +#define MT_CPTYPE_TERM_TYPE 4 +#define MT_CPTYPE_TERM_WIDTH 5 +#define MT_CPTYPE_TERM_HEIGHT 6 +#define MT_CPTYPE_PACKET_ERROR 7 +#define MT_CPTYPE_END_AUTH 9 + +int initPacket(unsigned char *data, unsigned char ptype, unsigned char *src, unsigned char *dst, unsigned short sessionkey, unsigned short counter) { + + // PACKET VERSION + data[0] = 1; + + // PACKET TYPE + data[1] = ptype; + + // src ethernet address + etherAddrton(data + 2, src); + + // dst ethernet address + etherAddrton(data + 8, dst); + + data[14] = sessionkey >> 8; + data[15] = sessionkey & 0xff; + + data[16] = 0x00; + data[17] = 0x15; + + data[18] = (counter >> 24) & 0xff; + data[19] = (counter >> 16) & 0xff; + data[20] = (counter >> 8) & 0xff; + data[21] = counter & 0xff; + + return 22; +} + +int addControlPacket(unsigned char *data, unsigned char cptype, unsigned char *cpdata, int data_len) { + data[0] = 0x56; + data[1] = 0x34; + data[2] = 0x12; + data[3] = 0xff; + + // Control packet type + data[4] = cptype; + + // Data length + data[5] = (data_len >> 24) & 0xff; + data[6] = (data_len >> 16) & 0xff; + data[7] = (data_len >> 8) & 0xff; + data[8] = data_len & 0xff; + + if (data_len) { + memcpy(data+9, cpdata, data_len); + } + + return 9+data_len; +} + +struct mt_mactelnet_hdr { unsigned char ver; - unsigned char packet_type; + unsigned char ptype; unsigned char srcaddr[6]; unsigned char dstaddr[6]; - unsigned short sessionkey; - unsigned short magic; + unsigned short seskey; unsigned int counter; + unsigned char *data; }; -#define MT_PTYPE_SESSIONSTART 0 -#define MT_PTYPE_DATA 1 -#define MT_PTYPE_ACK 2 -#define MT_PTYPE_END 255 +void parsePacket(unsigned char *data, struct mt_mactelnet_hdr *pkthdr) { + pkthdr->ver = data[0]; + pkthdr->ptype = data[1]; + memcpy(pkthdr->srcaddr, data+2,6); + memcpy(pkthdr->dstaddr, data+8,6); + pkthdr->seskey = data[16] << 8 | data[17]; + pkthdr->counter = data[18] << 24 | data[19] << 16 | data[20] << 8 | data[21]; + pkthdr->data = data + 22; +} + +int sockfd; +int counter=0; +unsigned char *src = "00:e0:81:b5:ac:8e"; +unsigned char *dst = "00:0c:42:43:58:a4"; + +void parseControlPacket(unsigned char *data, int data_len) { + unsigned char magic[] = { 0x56, 0x34, 0x12, 0xff }; + if (memcmp(data,&magic,4) == 0) { + if (DEBUG) + printf("\tControl packet:\n\t\tType: %d\n\t\tLength: %d\n", data[4], data[5]<<24|data[6]<<16|data[7]<<8|data[8]); + if (data_len - 9 - (data[4], data[5]<<24|data[6]<<16|data[7]<<8|data[8]) > 0) { + parseControlPacket(data + 9 + (data[4], data[5]<<24|data[6]<<16|data[7]<<8|data[8]), data_len - 9 - (data[4], data[5]<<24|data[6]<<16|data[7]<<8|data[8])); + } + + if (data[4] == 1) { + printf("Connected. Enter username & password.\n\n"); // TODOD: Teh good shiat + } + } +} + +void handlePacket(unsigned char *data, int data_len) { + struct mt_mactelnet_hdr pkthdr; + parsePacket(data, &pkthdr); + + if (DEBUG) + printf("Received packet:\n\tVersion %d\n\tType: %d\n\tSesskey: %d\n\tCounter: %d\n\n", pkthdr.ver, pkthdr.ptype, pkthdr.seskey, pkthdr.counter); + + if (pkthdr.ptype == MT_PTYPE_DATA) { + char odata[200]; + int plen=0,result=0; + counter += data_len - 22; + plen = initPacket(odata, MT_PTYPE_ACK, src, dst, pkthdr.seskey, counter); + result = sendCustomUDP(sockfd, src, dst, "213.236.240.252", 20561, "255.255.255.255", 20561, odata, plen); + if (DEBUG) + printf("ACK: Plen = %d, Send result: %d\n", plen, result); + + if (data_len - 22 > 0) { + parseControlPacket(data + 22, data_len - 22); + } + } +} int main (int argc, char **argv) { - int sockfd; int outsockfd; int result; char data[200]; struct sockaddr_in si_me; char buff[1500]; - struct mactelnet_cli_hdr outpacket; + int plen = 0; + int sessionkey=0; + + srand(time(NULL)); sockfd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); outsockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); @@ -38,82 +155,39 @@ int main (int argc, char **argv) { si_me.sin_port = htons(20561); si_me.sin_addr.s_addr = htonl(INADDR_ANY); - if (bind(outsockfd, &si_me, sizeof(si_me))==-1) { + if (bind(outsockfd, (struct sockaddr *)&si_me, sizeof(si_me))==-1) { fprintf(stderr, "Error binding to port 20561\n"); return 1; } - outpacket.ver = 1; - outpacket.packet_type = MT_PTYPE_SESSIONSTART; - etherAddrton(outpacket.srcaddr, "00:e0:81:b5:ac:8e"); - etherAddrton(outpacket.dstaddr, "00:0c:42:43:58:a4"); - outpacket.sessionkey = 1234; - outpacket.magic = 0x1500; - outpacket.counter = 0; -/* - data[0] = 1; - data[1] = 0; - - etherAddrton(&data[2], "00:e0:81:b5:ac:8e"); - etherAddrton(&data[8], "00:0c:42:43:58:a4"); - - data[14] = 22; - data[15] = 12; - data[16] = 0; - data[17] = 0x15; - - data[18] = 0; - data[19] = 0; + sessionkey = rand() % 65535; - data[20] = 0; - data[21] = 0; - data[22] = 0; + printf("Connecting to %s...\n", dst); - data[23] = 0; -*/ - result = sendCustomUDP(sockfd, "00:e0:81:b5:ac:8e", "00:0c:42:43:58:a4", "213.236.240.252", 20561, "255.255.255.255", 20561, (unsigned char *)&outpacket, sizeof(outpacket)); - printf("Send result: %d\n", result); + plen = initPacket(data, MT_PTYPE_SESSIONSTART, src, dst, sessionkey, 0); + result = sendCustomUDP(sockfd, src, dst, "213.236.240.252", 20561, "255.255.255.255", 20561, data, plen); + if (DEBUG) + printf("Plen = %d, Send result: %d\n", plen, result); + if (DEBUG) + printf("Sessionkey: %d\n", sessionkey); result = recvfrom(outsockfd, buff, 1400, 0, 0, 0); - printf("receive result: %d\n", result); + handlePacket(buff, result); + // TODO: Should resubmit whenever a PTYPE_DATA packet is sent, and an ACK packet with correct datacounter is received + // or time out the connection, in all other cases. + plen = initPacket(data, MT_PTYPE_DATA, src, dst, sessionkey, 0); + plen += addControlPacket(data + plen, MT_CPTYPE_BEGINAUTH, NULL, 0); - data[0] = 1; - data[1] = 1; - - etherAddrton(&data[2], "00:e0:81:b5:ac:8e"); - etherAddrton(&data[8], "00:0c:42:43:58:a4"); - - data[14] = 22; - data[15] = 12; - data[16] = 0; - data[17] = 0x15; - - data[18] = 0; - data[19] = 0; - data[20] = 0; - data[21] = 1; - - data[22] = 0x56; - data[23] = 0x34; - data[24] = 0x12; - data[25] = 0xff; - - // type - data[26] = 0; - - //len - data[27] = 0; - data[28] = 0; - data[29] = 0; - data[30] = 0; - - result = sendCustomUDP(sockfd, "00:e0:81:b5:ac:8e", "00:0c:42:43:58:a4", "213.236.240.252", 20561, "255.255.255.255", 20561, data, 31); - printf("Send result: %d\n", result); + result = sendCustomUDP(sockfd, src, dst, "213.236.240.252", 20561, "255.255.255.255", 20561, data, plen); + if (DEBUG) + printf("Plen = %d, Send result: %d\n", plen, result); result = recvfrom(outsockfd, buff, 1400, 0, 0, 0); - printf("receive result: %d\n", result); + handlePacket(buff, result); + result = recvfrom(outsockfd, buff, 1400, 0, 0, 0); + handlePacket(buff, result); close(sockfd); @@ -10,6 +10,51 @@ #include <linux/if_arp.h> #include <stdio.h> +unsigned short udp_sum_calc(unsigned short len_udp, unsigned char src_addr[],unsigned char dest_addr[], unsigned char buff[]) { + unsigned short prot_udp=17; + unsigned short padd=0; + unsigned short word16; + unsigned long sum; + int i; + + // Find out if the length of data is even or odd number. If odd, + // add a padding byte = 0 at the end of packet + if (len_udp % 2 == 1){ + padd=1; + buff[len_udp]=0; + } + + //initialize sum to zero + sum=0; + + // make 16 bit words out of every two adjacent 8 bit words and + // calculate the sum of all 16 vit words + for (i=0;i<len_udp+padd;i=i+2){ + word16 =((buff[i]<<8)&0xFF00)+(buff[i+1]&0xFF); + sum = sum + (unsigned long)word16; + } + // add the UDP pseudo header which contains the IP source and destinationn addresses + for (i=0;i<4;i=i+2){ + word16 =((src_addr[i]<<8)&0xFF00)+(src_addr[i+1]&0xFF); + sum=sum+word16; + } + for (i=0;i<4;i=i+2){ + word16 =((dest_addr[i]<<8)&0xFF00)+(dest_addr[i+1]&0xFF); + sum=sum+word16; + } + // the protocol number and the length of the UDP packet + sum = sum + prot_udp + len_udp; + + // keep only the last 16 bits of the 32 bit calculated sum and add the carries + while (sum>>16) + sum = (sum & 0xFFFF)+(sum >> 16); + + // Take the one's complement of sum + sum = ~sum; + + return ((unsigned short) sum); +} + //#define ETH_FRAME_LEN 1518 unsigned short in_cksum(unsigned short *addr, int len) { @@ -114,7 +159,9 @@ int sendCustomUDP(const int socket, const char *sourcemac, const char *destmac, // UDP Header udp->source = htons(20561); udp->dest = htons(20561); + udp->check = 0; udp->len = htons(sizeof(struct udphdr) + datalen); + //udp->check = udp_sum_calc(datalen+8, (unsigned char *)&(ip->saddr), (unsigned char *)&(ip->daddr), (unsigned char *)udp); memcpy(resten, data, datalen); |