#include <stdio.h>

#include <string.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <arpa/inet.h>

#include <sys/wait.h>

#include <sys/socket.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <signal.h>

#include <openssl/sha.h>

#include <stdlib.h>

#include <ctype.h>

#include "RSA.c"

int listenSocket = 0;

int connectionSocket = 0;

char buffer[1024];

struct sockaddr_in s_serv_addr;

int portno = 5005;

char IP[25];

char perm;

key_pair public, private;

int initDownload(char *);

char* sendMsg(char *, int);

char *decode_string(char *);

void get_hash(char * data, char * buf) {

int i;

unsigned char hash[SHA_DIGEST_LENGTH];

memset(hash, 0x0, SHA_DIGEST_LENGTH);

memset(buf, 0x0, SHA_DIGEST_LENGTH);

SHA1((unsigned char *)data, strlen(data), hash);

for (i=0; i < SHA_DIGEST_LENGTH; i++) {

sprintf((char*)&(buf[i*2]), "%02x", hash[i]);

}

// printf("SHA1 of %s is %s\n", data, buf);

}

void cpy(char * a, char * b) {

int i, j;

i=j=0;

while (b[i]!='\0') {

a[i] = b[i];

i++;

}

a[i] = '\0';

}

int main(int argc, char **argv) {

listenSocket = socket(AF_INET,SOCK_STREAM,0);

KeyGen(&public, &private);

strcpy(IP, argv[1]);

char * buf;

buf = strdup(argv[2]);

char filename[50];

char chat_msg[50];

char * returncode;

bzero(filename, 50);

filename[0] = 'k'; // Send Public Key

filename[1] = '\0';

sprintf(filename+1, "%lld:", public.public_key.e);

sprintf(filename+strlen(filename), "%lld\0", public.public_key.n);

printf("Key generated: %s\n", filename);

sendMsg(filename, 0);

bzero(filename, 50);

cpy(filename+1, buf);

filename[0] = 'd'; // Get File

initDownload(filename);

return 0;

}

char* replace(char* string, char replaceThis, char replaceWith)

{

int l = strlen(string);

int i;

for (i = 0; i < l; ++i)

{

if(string[i] == replaceThis)

string[i] = replaceWith;

}

return string;

}

char * sendMsg(char * msg, int wait) {

msg = replace(msg,' ', '&');

char returncode[1024];

int ClientSocket = 0;

struct sockaddr_in c_serv_addr;

ClientSocket = socket(AF_INET,SOCK_STREAM,0);

c_serv_addr.sin_family = AF_INET;

c_serv_addr.sin_port = htons(portno);

c_serv_addr.sin_addr.s_addr = inet_addr(IP);

while(connect(ClientSocket,(struct sockaddr *)&c_serv_addr,sizeof(c_serv_addr))<0);

bzero(buffer,1024);

sscanf(msg, "%s", buffer);

if(send(ClientSocket,buffer,strlen(buffer),0)<0)

printf("ERROR while writing to the socket\n");

bzero(buffer,1024);

if (wait == 1) {

if(recv(ClientSocket,buffer,1024,0)<0)

printf("ERROR while reading from the socket\n");

sscanf(buffer, "%s", returncode);

close(ClientSocket);

return returncode;

}

}

int initDownload(char * filename) {

char returncode[1024];

int ClientSocket = 0;

int ret;

char * decoded;

int counter, idx;

char c;

char hashed[SHA_DIGEST_LENGTH];

int i;

long long int encrypted, decrypted;

long long int fileSize;

char encoded[5];

struct sockaddr_in c_serv_addr;

ClientSocket = socket(AF_INET,SOCK_STREAM,0);

if(ClientSocket<0)

{

printf("ERROR WHILE CREATING A SOCKET\n");

return 0;

}

c_serv_addr.sin_family = AF_INET;

c_serv_addr.sin_port = htons(portno);

c_serv_addr.sin_addr.s_addr = inet_addr(IP);

while(connect(ClientSocket,(struct sockaddr *)&c_serv_addr,sizeof(c_serv_addr))<0);

bzero(buffer,1024);

sscanf(filename, "%s", buffer);

if(send(ClientSocket,buffer,strlen(buffer),0)<0)

printf("ERROR while writing to the socket\n");

bzero(buffer,1024);

strcat(filename, "_received");

FILE *fp = fopen(filename+1, "wb");

if(recv(ClientSocket,buffer,1024,0)<0)

printf("ERROR while reading from the socket\n");

sscanf(buffer, "%s", returncode);

if(returncode[0]=='x') {

i=1;

fileSize = 0;

while(returncode[i]!='\0') {

fileSize *= 10;

fileSize += returncode[i++]-'0';

}

bzero(buffer,1024);

ret = 1;

for (ret = 0; ret<fileSize/2; ret++)

{

bzero(buffer,1024);

recv(ClientSocket,buffer,1024,0);

bzero(hashed, 20);

idx=0;

counter = 0;

c = buffer[idx];

encrypted = 0;

while (c!=':') {

encrypted = encrypted + (c - '0');

encrypted = encrypted * 10;

idx++;

counter++;

c = buffer[idx];

}

encrypted = encrypted/10;

decrypted = Decryption(encrypted, private);

if (decrypted < 10) {

sprintf(encoded, "0%lld", decrypted);

}

else {

sprintf(encoded, "%lld", decrypted);

}

decoded = decode_string(encoded);

fwrite(decoded, sizeof(char),strlen(decoded), fp);

printf("Received [ %d of %d ] ...\r", ret+1, fileSize/2);

}

printf("\n");

bzero(buffer,1024);

fclose(fp);

}

printf("File download complete.\n");

printf("Closing Connection\n");

close(ClientSocket);

return 1;

}

char *decode_string(char *text)

{

char dec[2];

char *send = (char *)malloc(sizeof(char) * 400000);

int size = 0;

int make;

if(text == NULL)

return NULL;

int i;

for(i = 0; i < strlen(text); i += 2)

{

dec[0] = text[i];

dec[1] = text[i + 1];

make = (((int)dec[0] - '0') * 10) + ((int)dec[1] - '0');

if(make == 0)

send[size++] = ' ';

else if((make >= 1) && (make <= 25))

send[size++] = 'A' + make - 1;

else if((make >= 26) && (make <= 51))

send[size++] = (make - 26) + 'a';

else if((make >= 52) && (make <= 61))

send[size++] = (make - 52) + '0';

else if(make == 62)

send[size++] = ',';

else if(make == 63)

send[size++] = '.';

else if(make == 64)

send[size++] = '!';

}

send[size++] = '\0';

return send;

}