c-ipfs/exchange/bitswap/network.c
2017-08-02 08:53:34 -05:00

147 lines
5.2 KiB
C

/***
* This implements the BitswapNetwork. Members of this network can fill requests and
* smartly handle queues of local and remote requests.
*
* For a somewhat accurate diagram of how this may work, @see https://github.com/ipfs/js-ipfs-bitswap
*/
#include "libp2p/utils/logger.h"
#include "ipfs/exchange/bitswap/network.h"
#include "ipfs/exchange/bitswap/peer_request_queue.h"
/****
* send a message to a particular peer
* @param context the BitswapContext
* @param peer the peer that is the recipient
* @param message the message to send
*/
int ipfs_bitswap_network_send_message(const struct BitswapContext* context, struct Libp2pPeer* peer, const struct BitswapMessage* message) {
// get a connection to the peer
if (peer->connection_type != CONNECTION_TYPE_CONNECTED) {
libp2p_peer_connect(&context->ipfsNode->identity->private_key, peer, context->ipfsNode->peerstore, 10);
if(peer->connection_type != CONNECTION_TYPE_CONNECTED)
return 0;
}
// protobuf the message
size_t buf_size = ipfs_bitswap_message_protobuf_encode_size(message);
uint8_t* buf = (uint8_t*) malloc(buf_size + 20);
if (buf == NULL)
return 0;
if (!ipfs_bitswap_message_protobuf_encode(message, &buf[20], buf_size, &buf_size)) {
free(buf);
return 0;
}
// tack on the protocol header
memcpy(buf, "/ipfs/bitswap/1.1.0\n", 20);
buf_size += 20;
// send it
int bytes_written = peer->sessionContext->default_stream->write(peer->sessionContext, buf, buf_size);
if (bytes_written <= 0) {
free(buf);
return 0;
}
free(buf);
return 1;
}
/***
* Remove a cid from the queue
* @param cids the vector of cids
* @param cid the cid to remove
* @returns true(1) on success, false(0) otherwise
*/
int ipfs_bitswap_network_remove_cid_from_queue(struct Libp2pVector* collection, struct Cid* cid) {
if (collection == NULL || cid == NULL)
return 0;
for(int i = 0; i < collection->total; collection++) {
const struct CidEntry* current = (const struct CidEntry*)libp2p_utils_vector_get(collection, i);
if (ipfs_cid_compare(current->cid, cid) == 0) {
libp2p_utils_vector_delete(collection, i);
return 1;
}
}
return 0;
}
/***
* Handle a raw incoming bitswap message from the network
* @param node us
* @param sessionContext the connection context
* @param bytes the message
* @param bytes_size the size of the message
* @returns true(1) on success, false(0) otherwise.
*/
int ipfs_bitswap_network_handle_message(const struct IpfsNode* node, const struct SessionContext* sessionContext, const uint8_t* bytes, size_t bytes_length) {
struct BitswapContext* bitswapContext = (struct BitswapContext*)node->exchange->exchangeContext;
// strip off the protocol header
int start = -1;
for(int i = 0; i < bytes_length; i++) {
if (bytes[i] == '\n') {
start = i+1;
break;
}
}
if (start == -1)
return 0;
// un-protobuf the message
struct BitswapMessage* message = NULL;
if (!ipfs_bitswap_message_protobuf_decode(&bytes[start], bytes_length - start, &message))
return 0;
// process the message
// payload - what we want
if (message->payload != NULL) {
for(int i = 0; i < message->payload->total; i++) {
struct Block* blk = (struct Block*)libp2p_utils_vector_get(message->payload, i);
node->exchange->HasBlock(node->exchange, blk);
}
}
// wantlist - what they want
if (message->wantlist != NULL && message->wantlist->entries != NULL && message->wantlist->entries->total > 0) {
// get the peer
if (sessionContext->remote_peer_id == NULL) {
ipfs_bitswap_message_free(message);
return 0;
}
struct Libp2pPeer* peer = libp2p_peerstore_get_or_add_peer_by_id(node->peerstore, (unsigned char*)sessionContext->remote_peer_id, strlen(sessionContext->remote_peer_id));
if (peer == NULL) {
libp2p_logger_error("bitswap_network", "Unable to find or add peer %s of length %d to peerstore.\n", sessionContext->remote_peer_id, strlen(sessionContext->remote_peer_id));
ipfs_bitswap_message_free(message);
return 0;
}
// find the queue
struct PeerRequestEntry* queueEntry = ipfs_bitswap_peer_request_queue_find_entry(bitswapContext->peerRequestQueue, peer);
if (queueEntry == NULL) {
// add the queue
struct PeerRequest* peerRequest =ipfs_bitswap_peer_request_new();
peerRequest->peer = peer;
ipfs_bitswap_peer_request_queue_add(bitswapContext->peerRequestQueue, peerRequest);
queueEntry = ipfs_bitswap_peer_request_queue_find_entry(bitswapContext->peerRequestQueue, peer);
if (queueEntry == NULL) {
ipfs_bitswap_message_free(message);
return 0;
}
}
for(int i = 0; i < message->wantlist->entries->total; i++) {
struct WantlistEntry* entry = (struct WantlistEntry*) libp2p_utils_vector_get(message->wantlist->entries, i);
// turn the "block" back into a cid
struct Cid* cid = NULL;
if (!ipfs_cid_protobuf_decode(entry->block, entry->block_size, &cid) || cid->hash_length == 0) {
libp2p_logger_error("bitswap_network", "Message had invalid CID\n");
ipfs_cid_free(cid);
return 0;
}
if (entry->cancel)
ipfs_bitswap_network_remove_cid_from_queue(queueEntry->current->cids_they_want, cid);
else {
struct CidEntry* cidEntry = ipfs_bitswap_peer_request_cid_entry_new();
cidEntry->cid = cid;
cidEntry->cancel = 0;
libp2p_utils_vector_add(queueEntry->current->cids_they_want, cidEntry);
}
}
}
return 1;
}