void handle_message(cjdnsadmin_t *adm, char *buffer, ssize_t len) {
// TODO: fix memory leak
struct bencode *b = ben_decode(buffer, len);
if (!b) {
fprintf(stderr, "bencode error: %lu\n",len);
printf("message from cjdns: \"%*s\"\n", (int)len, buffer);
return;
}
// Get IPs
struct bencode *table = ben_dict_get_by_str(b, "routingTable");
size_t i, num_items = ben_list_len(table);
for (i = 0; i < num_items; i++) {
struct bencode *item = ben_list_get(table, i);
struct bencode *ip = ben_dict_get_by_str(item, "ip");
if (ben_is_str(ip)) {
const char *ip_str = ben_str_val(ip);
if (adm->on_found_ip) {
(*adm->on_found_ip)(adm->on_found_ip_obj, ip_str);
}
}
}
// check if there is more
struct bencode *more = ben_dict_get_by_str(b, "more");
int more_int = more && ben_is_int(more) && ben_int_val(more);
if (more_int == 1) {
// get the next page of the routing table
adm->fetch_peers_page++;
cjdnsadmin_fetch_peers(adm);
} else {
// start from the first page next time
adm->fetch_peers_page = 0;
}
ben_free(b);
}
/* handle_announcement reads an announcement document to find some peers to download from.
Puts em in benPeers, and we then handle the peer scanning or whatever in the main function. */
void handle_announcement(char *ptr, size_t size) {
struct bencode* anno = ben_decode(ptr,size);
printf("Torrent has %lld seeds and %lld downloading peers. \n",
((struct bencode_int*)ben_dict_get_by_str(anno,"complete"))->ll,
((struct bencode_int*)ben_dict_get_by_str(anno,"incomplete"))->ll);
benPeers = (struct bencode_list*)ben_dict_get_by_str(anno,"peers");
}
/* handle_announcement reads an announcement document to find some peers to download from.
start a new tread for each peer.
*/
void handle_announcement(char *ptr, size_t size) {
struct bencode* anno = ben_decode(ptr,size);
printf("Torrent has %lld seeds and %lld downloading peers. \n",
((struct bencode_int*)ben_dict_get_by_str(anno,"complete"))->ll,
((struct bencode_int*)ben_dict_get_by_str(anno,"incomplete"))->ll);
struct bencode_list *peers = (struct bencode_list*)ben_dict_get_by_str(anno,"peers");
// handle the binary case
if(peers->type == BENCODE_STR) {
printf("Got binary list of peers\n");
struct peer_addr *peerlist = (struct peer_addr*)((struct bencode_str*)peers)->s;
for(int i=0;i<((struct bencode_str*)peers)->len/6;i++) {
struct in_addr a;
a.s_addr = peerlist[i].addr;
printf("Found peer %s:%d\n",inet_ntoa(a),ntohs(peerlist[i].port));
connect_all_peers(&peerlist[i]);
}
}
// handle the bencoded case
else {
for(int i=0;i<peers->n;i++) {
printf("Got bencoded list of peers\n");
struct bencode *peer = peers->values[i];
char *address = ((struct bencode_str*)ben_dict_get_by_str(peer,"ip"))->s;
unsigned short port = ((struct bencode_int*)ben_dict_get_by_str(peer,"port"))->ll;
printf("Found peer %s:%d\n",address,port);
struct peer_addr *peeraddr = malloc(sizeof(struct peer_addr));
peeraddr->addr=inet_addr(address);
peeraddr->port=htons(port);
connect_all_peers(peeraddr);
}
}
listen_from_peers();
}
void write_block(char* data, int piece, int offset, int len, int acquire_lock) {
FILE *outfile;
//dev_notifier();
int accumulated_file_length = 0;
int block_start = piece*piece_length+offset;
struct bencode_list* files = (struct bencode_list*)ben_dict_get_by_str(info,"files");
// multi-file case
if(files) {
for(int i=0;i<files->n;i++) {
struct bencode* file = files->values[i];
struct bencode_list* path = (struct bencode_list*)ben_dict_get_by_str(file,"path");
int file_length=((struct bencode_int*)ben_dict_get_by_str(file,"length"))->ll;
printf("start %d len %d accum %d filelen %d\n",block_start,len,accumulated_file_length,file_length);
// at least part of the block belongs in this file
if((block_start >= accumulated_file_length) && (block_start < accumulated_file_length+file_length)) {
char filename[255];
mkdir(((struct bencode_str*)ben_dict_get_by_str(info,"name"))->s,0777);
chmod(((struct bencode_str*)ben_dict_get_by_str(info,"name"))->s,07777);
sprintf(filename,"%s/",((struct bencode_str*)ben_dict_get_by_str(info,"name"))->s);
for(int j=0;j<path->n;j++) {
if(j<(path->n-1)) {
sprintf(filename+strlen(filename),"%s/",((struct bencode_str*)path->values[j])->s);
mkdir(filename,0777);
chmod(filename,07777);
}
else
sprintf(filename+strlen(filename),"%s",((struct bencode_str*)path->values[j])->s);
}
int outfile = open(filename,O_RDWR|O_CREAT,0777);
if(outfile == -1) {
fprintf(stderr,"filename: %s\n",filename);
perror("Couldn't open file for writing");
exit(1);
}
int offset_into_file = block_start - accumulated_file_length;
int remaining_file_length = file_length - offset_into_file;
lseek(outfile,offset_into_file,SEEK_SET);
if(remaining_file_length > len) {
write(outfile,data,len);
close(outfile);
goto cleanup;
}
else {
write(outfile,data,remaining_file_length);
close(outfile);
write_block(data+remaining_file_length,piece,offset+remaining_file_length,len-remaining_file_length,0);
goto cleanup;
}
}
accumulated_file_length+=file_length;
}
}
// single-file case
else {
struct bencode_str* name = (struct bencode_str*)ben_dict_get_by_str(info,"name");
if(name) {
FILE *outfile = fopen(name->s,"r+");
file_length = ((struct bencode_int*)ben_dict_get_by_str(info,"length"))->ll;
// write the data to the right spot in the file
fseek(outfile,piece*piece_length+offset,SEEK_SET);
fwrite(data,1,len,outfile);
fclose(outfile);
}
else {
printf("No name?\n");
exit(1);
}
}
cleanup:
return;
}
int main(int argc, char** argv) {
//setvbuf(stdout,screenbuf,_IOFBF,10000);
setbuf(stdout, NULL);
setbuf(stderr, NULL);
// create a global peer_id for this session. Every peer_id should include -CS450-.
for(int i=strlen(peer_id);i<20;i++)
peer_id[i]='0'+random()%('Z'-'0'); // random numbers/letters between 0 and Z
// make sure the torrent file exists
struct stat file_stat;
if(stat(argv[1],&file_stat)) {
perror("Error opening file.");
exit(1);
}
// map .torrent file into memory, and parse contents
int fd = open(argv[1],O_RDONLY);
char *buf = mmap(0,file_stat.st_size,PROT_READ,MAP_SHARED,fd,0);
if(buf==(void*)-1) {
perror("couldn't mmap file");
exit(1);
}
size_t off = 0;
int error = 0;
torrent = (struct bencode_dict*)ben_decode2(buf,file_stat.st_size,&off,&error);
if(!torrent) {
printf("Got error %d, perhaps a malformed torrent file?\n",error);
exit(1);
}
// pull out the .info part, which has stuff about the file we're downloading
info = (struct bencode*)ben_dict_get_by_str((struct bencode*)torrent,"info");
struct bencode_list* files = (struct bencode_list*)ben_dict_get_by_str(info,"files");
// multi-file case
if(files) {
for(int i=0;i<files->n;i++) {
struct bencode* file = files->values[i];
struct bencode_list* path = (struct bencode_list*)ben_dict_get_by_str(file,"path");
printf("Filename %s/%s\n",((struct bencode_str*)ben_dict_get_by_str(info,"name"))->s,((struct bencode_str*)path->values[0])->s);
// accumulate a total length so we know how many pieces there are
file_length+=((struct bencode_int*)ben_dict_get_by_str(file,"length"))->ll;
}
}
// single-file case
else {
FILE *outfile;
struct bencode_str* name = (struct bencode_str*)ben_dict_get_by_str(info,"name");
if(name) {
outfile = fopen(name->s,"r+");
file_length = ((struct bencode_int*)ben_dict_get_by_str(info,"length"))->ll;
}
}
piece_length = ((struct bencode_int*)ben_dict_get_by_str(info,"piece length"))->ll;
piece_status =calloc(1,sizeof(int)*(int)(file_length/piece_length+1));
/* compute the message digest and info_hash from the "info" field in the torrent */
size_t len;
char info_hash[100];
char* encoded = ben_encode(&len,(struct bencode*)info);
SHA1(encoded,len,digest); // digest is a global that holds the raw 20 bytes
piece_occurence_value = calloc(1,sizeof(int)*(int)(file_length/piece_length+1));
// info_hash is a stringified version of the digest, for use in the announce URL
memset(info_hash,0,100);
for(int i=0;i<20;i++)
sprintf(info_hash+3*i,"%%%02x",digest[i]);
// compile a suitable announce URL for our document
sprintf(announce_url,"%s?info_hash=%s&peer_id=%s&port=6881&left=%d",((struct bencode_str*)ben_dict_get_by_str((struct bencode*)torrent,"announce"))->s,info_hash,peer_id,file_length);
printf("Announce URL: %s\n",announce_url);
start_peers();
}
int main(int argc, char** argv) {
if(argc<2) {
fprintf(stderr,"Usage: ./hw4 <torrent file>\n");
exit(1);
}
setvbuf(stdout,screenbuf,_IOFBF,10000);
// create a global peer_id for this session. Every peer_id should include -OBCS342-.
for(int i=strlen(peer_id);i<20;i++)
peer_id[i]='0'+random()%('Z'-'0'); // random numbers/letters between 0 and Z
// make sure the torrent file exists
struct stat file_stat;
if(stat(argv[1],&file_stat)) {
perror("Error opening file.");
exit(1);
}
// map .torrent file into memory, and parse contents
int fd = open(argv[1],O_RDONLY);
char *buf = mmap(0,file_stat.st_size,PROT_READ,MAP_SHARED,fd,0);
if(buf==(void*)-1) {
perror("couldn't mmap file");
exit(1);
}
size_t off = 0;
int error = 0;
torrent = (struct bencode_dict*)ben_decode2(buf,file_stat.st_size,&off,&error);
if(!torrent) {
printf("Got error %d, perhaps a malformed torrent file?\n",error);
exit(1);
}
// pull out the .info part, which has stuff about the file we're downloading
info = (struct bencode*)ben_dict_get_by_str((struct bencode*)torrent,"info");
struct bencode_list* files = (struct bencode_list*)ben_dict_get_by_str(info,"files");
// multi-file case
if(files) {
for(int i=0;i<files->n;i++) {
struct bencode* file = files->values[i];
struct bencode_list* path = (struct bencode_list*)ben_dict_get_by_str(file,"path");
printf("Filename %s/%s\n",((struct bencode_str*)ben_dict_get_by_str(info,"name"))->s,((struct bencode_str*)path->values[0])->s);
// accumulate a total length so we know how many pieces there are
file_length+=((struct bencode_int*)ben_dict_get_by_str(file,"length"))->ll;
}
}
// single-file case
else {
struct bencode_str* name = (struct bencode_str*)ben_dict_get_by_str(info,"name");
if(name) {
file_length = ((struct bencode_int*)ben_dict_get_by_str(info,"length"))->ll;
}
}
fflush(stdout);
piece_length = ((struct bencode_int*)ben_dict_get_by_str(info,"piece length"))->ll;
// create our output file, and set up a piece_status array
piece_status = calloc(1,sizeof(int)*(int)(file_length/piece_length+1)); //start with an empty bitfield
/* compute the message digest and info_hash from the "info" field in the torrent */
size_t len;
char info_hash[100];
char* encoded = ben_encode(&len,(struct bencode*)info);
SHA1(encoded,len,digest); // digest is a global that holds the raw 20 bytes
// info_hash is a stringified version of the digest, for use in the announce URL
memset(info_hash,0,100);
for(int i=0;i<20;i++)
sprintf(info_hash+3*i,"%%%02x",digest[i]);
// compile a suitable announce URL for our document
sprintf(announce_url,"%s?info_hash=%s&peer_id=%s&port=6881&left=%d",((struct bencode_str*)ben_dict_get_by_str((struct bencode*)torrent,"announce"))->s,info_hash,peer_id,file_length);
printf("Announce URL: %s\n",announce_url);
fflush(stdout);
start_peers();
// now benPeers has the peers list from handle_announcement; let's handle this
// handle the binary case
FD_ZERO(&readset);
FD_ZERO(&writeset); // zero out the sets before adding things to them
if(benPeers->type == BENCODE_STR) {
printf("Got binary list of peers\n");
// replace all occurrences of pa with peerlist[i]
struct peer_addr *peerlist = (struct peer_addr*)((struct bencode_str*)benPeers)->s;
for(int i=0;i<((struct bencode_str*)benPeers)->len/6;i++) {
struct in_addr a;
a.s_addr = peerlist[i].addr;
printf("Found peer %s:%d\n",inet_ntoa(a),ntohs(peerlist[i].port));
fprintf(stderr,"Connecting...\n");
struct peer_addr* peeraddr = (struct peer_addr*)&peerlist[i];
if(peer_connected(peeraddr->addr)) {
fprintf(stderr,"Already connected\n");
} else {
// open the socket
int s = socket(AF_INET, SOCK_STREAM,0);
if(s < 0){
perror("Error creating socket: ");
}
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = peeraddr->addr;
addr.sin_port = peeraddr->port;
// set up the timeout
struct timeval tv;
tv.tv_sec = 60;
if(setsockopt(s,SOL_SOCKET,SO_RCVTIMEO, (char *)&tv, sizeof tv))
perror("setsockopt");
int res = connect(s, (struct sockaddr*)&addr, sizeof(addr));
if(res == -1) {
fprintf(stderr,"Couldn't connect to %d \n", peeraddr->port);
fflush(stderr);
perror("Error while connecting: ");
} else {
printf("Connected!\n"); // for debugging purposes
// register the new peer in our list of peers
struct peer_state* peer = calloc(1,sizeof(struct peer_state));
peer->socket = s; // socket is current socket
peer->ip= peeraddr->addr; // address is the address of the current peer
peer->next = peers; // stick it at the front of the linked list
peer->connected = 0; // we're not connected until we've done handshaking
peer->choked = 1;
peer->incoming = malloc(BUFSIZE);
peer->bitfield = calloc(1,file_length/piece_length/8+1); // start with an empty bitfield
peers = peer; // make me the head of the LL
char protocol[] = "BitTorrent protocol";
unsigned char pstrlen = strlen(protocol);
unsigned char msg[pstrlen+49];
msg[0] = pstrlen;
memcpy(msg+1,protocol,pstrlen);
memcpy(msg+1+pstrlen+8,digest,20);
memcpy(msg+1+pstrlen+8+20,peer_id,20);
// put handshaking msg into all peers' outgoing
peer->outgoing_count = 0;
peer->outgoing = malloc(BUFSIZE);
memcpy(peer->outgoing+peer->outgoing_count, msg, sizeof msg);
peer->outgoing_count += sizeof msg;
FD_SET(s, &readset); // add s (fd of peer's socket) to the read and write sets
FD_SET(s, &writeset);
}
}
}
}
// handle the bencoded case
else {
for(int i=0;i<benPeers->n;i++) {
printf("Got bencoded list of peers\n");
struct bencode *peer = benPeers->values[i];
char *address = ((struct bencode_str*)ben_dict_get_by_str(peer,"ip"))->s;
unsigned short port = ((struct bencode_int*)ben_dict_get_by_str(peer,"port"))->ll;
printf("Found peer %s:%d\n",address,port);
fprintf(stderr,"Connecting...\n");
struct peer_addr *peeraddr = malloc(sizeof(struct peer_addr));
peeraddr->addr=inet_addr(address);
peeraddr->port=htons(port);
if(peer_connected(peeraddr->addr)) {
fprintf(stderr,"Already connected\n");
} else {
// open the socket
int s = socket(AF_INET, SOCK_STREAM,0);
if(s < 0){
perror("Error creating socket: ");
}
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = peeraddr->addr;
addr.sin_port = peeraddr->port;
// set up the timeout
struct timeval tv;
tv.tv_sec = 60;
if(setsockopt(s,SOL_SOCKET,SO_RCVTIMEO, (char *)&tv, sizeof tv))
perror("setsockopt");
// in a more ideal world, this would break out of the current iteration of the loop
int res = connect(s, (struct sockaddr*)&addr, sizeof(addr));
if(res == -1) {
fprintf(stderr,"Couldn't connect to %d \n", peeraddr->port);
fflush(stderr);
perror("Error while connecting: ");
} else {
printf("Connected!\n"); // for debugging purposes
// register the new peer in our list of peers
struct peer_state* peer = calloc(1,sizeof(struct peer_state));
peer->socket = s; // socket is current socket
peer->ip= peeraddr->addr; // address is the address of the current peer
peer->next = peers; // stick it at the front of the linked list
peer->connected = 0; // we're not connected until we've done handshaking
peer->choked = 1;
peer->incoming = malloc(BUFSIZE);
peer->bitfield = calloc(1,file_length/piece_length/8+1); // start with an empty bitfield
peers = peer; // make me the head of the LL
char protocol[] = "BitTorrent protocol";
unsigned char pstrlen = strlen(protocol);
unsigned char msg[pstrlen+49];
msg[0] = pstrlen;
memcpy(msg+1,protocol,pstrlen);
memcpy(msg+1+pstrlen+8,digest,20);
memcpy(msg+1+pstrlen+8+20,peer_id,20);
// put handshaking msg into all peers' outgoing
peer->outgoing_count = 0;
peer->outgoing = malloc(BUFSIZE);
memcpy(peer->outgoing+peer->outgoing_count, msg, sizeof msg);
peer->outgoing_count += sizeof msg;
FD_SET(s, &readset); // add s (fd of peer's socket) to the read and write sets
FD_SET(s, &writeset);
}
}
}
}
while(1) {
fd_set rtemp, wtemp;
FD_ZERO(&rtemp);
FD_ZERO(&wtemp); // zero out the temp sets
memcpy(&rtemp, &readset, sizeof readset);
memcpy(&wtemp, &writeset, sizeof writeset);
// timeout for the select call? probably too high
struct timeval tv;
tv.tv_sec = 0;
int selected = select(FD_SETSIZE, &rtemp, &wtemp, NULL, &tv);
struct peer_state* peerTemp = peers;
while(peerTemp) {
//printf("Current peer name is %s\n", inet_ntoa(*(struct in_addr *)&peerTemp->ip));
if(FD_ISSET(peerTemp->socket,&rtemp)) { // if we're reading
if(!peerTemp->connected) {
recv_handshake(peerTemp); // can all receive at once? or not?
FD_SET(peerTemp->socket, &readset);
} else {
int ret = receive_message(peerTemp); // we can just use the current receive_message fcn
if(ret == 2) {
handle_message(peerTemp);
} // else just keep on chuggin
}
//FD_SET(peerTemp->socket, &readset); // then add it to the readset, always
}
if(FD_ISSET(peerTemp->socket,&wtemp)) { // if we're writing
send_message(peerTemp);
}
peerTemp = peerTemp->next;
}
// if we don't have any missing blocks, breeaaaakk
if(missing_blocks() == 0)
break;
}
}
/* This needs to be fixed to work properly for multi-file torrents.
specifically, it needs to create the proper directory structure, rather than just concatenate directory and file names.
*/
void write_block(char* data, int piece, int offset, int len, int acquire_lock) {
FILE *outfile;
int accumulated_file_length = 0;
int block_start = piece*piece_length+offset;
struct bencode_list* files = (struct bencode_list*)ben_dict_get_by_str(info,"files");
// multi-file case
if(files) {
for(int i=0;i<files->n;i++) {
struct bencode* file = files->values[i];
struct bencode_list* path = (struct bencode_list*)ben_dict_get_by_str(file,"path");
// printf("Filename %s/%s\n",((struct bencode_str*)ben_dict_get_by_str(info,"name"))->s,((struct bencode_str*)path->values[0])->s);
// accumulate a total length so we know how many pieces there are
int file_length=((struct bencode_int*)ben_dict_get_by_str(file,"length"))->ll;
printf("start %d len %d accum %d filelen %d\n",block_start,len,accumulated_file_length,file_length);
fflush(stdout);
// at least part of the block belongs in this file
if((block_start >= accumulated_file_length) && (block_start < accumulated_file_length+file_length)) {
char filename[255];
mkdir(((struct bencode_str*)ben_dict_get_by_str(info,"name"))->s,0777);
chmod(((struct bencode_str*)ben_dict_get_by_str(info,"name"))->s,07777);
sprintf(filename,"%s/",((struct bencode_str*)ben_dict_get_by_str(info,"name"))->s);
for(int j=0;j<path->n;j++) {
if(j<(path->n-1)) {
sprintf(filename+strlen(filename),"%s/",((struct bencode_str*)path->values[j])->s);
mkdir(filename,0777);
chmod(filename,07777);
}
else
sprintf(filename+strlen(filename),"%s",((struct bencode_str*)path->values[j])->s);
}
int outfile = open(filename,O_RDWR|O_CREAT,0777);
if(outfile == -1) {
fprintf(stderr,"filename: %s\n",filename);
perror("Couldn't open file for writing");
exit(1);
}
int offset_into_file = block_start - accumulated_file_length;
int remaining_file_length = file_length - offset_into_file;
lseek(outfile,offset_into_file,SEEK_SET);
if(remaining_file_length > len) {
write(outfile,data,len);
close(outfile);
}
else {
if(debug) {
fprintf(stderr,"Uh-oh, write crossing file boundaries... watch out!\n");
fprintf(stderr,"Len %d offset %d filelen %d remaining file len %d\n",len,offset_into_file,file_length,remaining_file_length);
fflush(stdout);
}
write(outfile,data,remaining_file_length);
close(outfile);
write_block(data+remaining_file_length,piece,offset+remaining_file_length,len-remaining_file_length,0);
}
}
accumulated_file_length+=file_length;
}
}
// single-file case
else {
struct bencode_str* name = (struct bencode_str*)ben_dict_get_by_str(info,"name");
if(name) {
int outfile = open(name->s,O_RDWR|O_CREAT,0777);
file_length = ((struct bencode_int*)ben_dict_get_by_str(info,"length"))->ll;
// write the data to the right spot in the file
lseek(outfile,piece*piece_length+offset,SEEK_SET);
write(outfile, data,len);
close(outfile);
}
else {
printf("No name?\n");
exit(1);
}
}
}
