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c-libp2p/routing/dht_protocol.c

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#include <stdlib.h>
#include <string.h>
#include "libp2p/crypto/encoding/base58.h"
#include "libp2p/net/stream.h"
#include "libp2p/os/utils.h"
#include "libp2p/routing/dht_protocol.h"
#include "libp2p/record/message.h"
#include "libp2p/utils/linked_list.h"
#include "libp2p/utils/logger.h"
#include "libp2p/conn/session.h"
/***
* This is where kademlia and dht talk to the outside world
*/
int libp2p_routing_dht_can_handle(const struct StreamMessage* msg) {
if (msg == NULL || msg->data_size == 0 || msg->data == NULL)
return 0;
if (msg->data_size < 8)
return 0;
char* result = strnstr((char*)msg->data, "/ipfs/kad", msg->data_size);
if (result != NULL && result == (char*)msg->data)
return 1;
return 0;
}
int libp2p_routing_dht_shutdown(void* context) {
free(context);
return 1;
}
int libp2p_routing_dht_handle_msg(const struct StreamMessage* msg, struct Stream* stream, void* protocol_context) {
struct DhtContext* ctx = (struct DhtContext*)protocol_context;
if (!libp2p_routing_dht_handshake(stream))
return -1;
return (libp2p_routing_dht_handle_message(stream, ctx) == 0) ? -1 : 1;
}
struct Libp2pProtocolHandler* libp2p_routing_dht_build_protocol_handler(struct Peerstore* peer_store, struct ProviderStore* provider_store,
struct Datastore* datastore, struct Filestore* filestore) {
struct Libp2pProtocolHandler* handler = (struct Libp2pProtocolHandler*) malloc(sizeof(struct Libp2pProtocolHandler));
if (handler != NULL) {
struct DhtContext* ctx = (struct DhtContext*) malloc(sizeof(struct DhtContext));
ctx->peer_store = peer_store;
ctx->provider_store = provider_store;
ctx->datastore = datastore;
ctx->filestore = filestore;
handler->context = ctx;
handler->CanHandle = libp2p_routing_dht_can_handle;
handler->HandleMessage = libp2p_routing_dht_handle_msg;
handler->Shutdown = libp2p_routing_dht_shutdown;
}
return handler;
}
/***
* Helper method to protobuf a message
* @param message the message
* @param buffer where to put the results
* @param buffer_size the size of the results
* @returns true(1) on success, false(0) otherwise
*/
int libp2p_routing_dht_protobuf_message(struct KademliaMessage* message, unsigned char** buffer, size_t *buffer_size) {
*buffer_size = libp2p_message_protobuf_encode_size(message);
*buffer = malloc(*buffer_size);
if (!libp2p_message_protobuf_encode(message, *buffer, *buffer_size, buffer_size)) {
free(*buffer);
*buffer_size = 0;
return 0;
}
return 1;
}
/**
* Take existing stream and upgrade to the Kademlia / DHT protocol/codec
* @param context the context
* @returns true(1) on success, otherwise false(0)
*/
int libp2p_routing_dht_upgrade_stream(struct SessionContext* context) {
int retVal = 0;
char* protocol = "/ipfs/kad/1.0.0\n";
struct StreamMessage outgoing;
outgoing.data = (uint8_t*)protocol;
outgoing.data_size = strlen(protocol);
struct StreamMessage* results = NULL;
if (!context->default_stream->write(context, &outgoing)) {
libp2p_logger_error("dht_protocol", "Unable to write to stream during upgrade attempt.\n");
goto exit;
}
if (!context->default_stream->read(context, &results, 5)) {
libp2p_logger_error("dht_protocol", "Unable to read from stream during upgrade attempt.\n");
goto exit;
}
if (results == NULL || results->data_size != strlen(protocol)) {
libp2p_logger_error("dht_protocol", "Expected response size incorrect during upgrade attempt.\n");
goto exit;
}
if (strncmp((char*)results->data, protocol, results->data_size) != 0) {
libp2p_logger_error("dht_protocol", "Expected %s but received %s.\n", protocol, results);
goto exit;
}
retVal = 1;
exit:
libp2p_stream_message_free(results);
results = NULL;
return retVal;
}
/**
* Handle a client requesting an upgrade to the DHT protocol
* @param stream the stream to the remote
* @returns true(1) on success, otherwise false(0)
*/
int libp2p_routing_dht_handshake(struct Stream* stream) {
char* protocol = "/ipfs/kad/1.0.0\n";
struct StreamMessage outgoing;
outgoing.data = (uint8_t*) protocol;
outgoing.data_size = strlen(protocol);
return stream->write(stream->stream_context, &outgoing);
}
/**
* A remote client has requested a ping
* @param message the message
* @param buffer where to put the results
* @param buffer_size the length of the results
* @returns true(1) on success, false(0) otherwise
*/
int libp2p_routing_dht_handle_ping(struct KademliaMessage* message, unsigned char** buffer, size_t *buffer_size) {
// just turn message back into a protobuf and send it back...
return libp2p_routing_dht_protobuf_message(message, buffer, buffer_size);
}
/**
* See if we have information as to who can provide this item
* @param stream the incoming stream
* @param message the message from the caller, contains a key
* @param protocol_context the context
* @param results where to put the results
* @param results_size the size of the results
* @returns true(1) on success, false(0) otherwise
*/
int libp2p_routing_dht_handle_get_providers(struct Stream* stream, struct KademliaMessage* message, struct DhtContext* protocol_context,
unsigned char** results, size_t* results_size) {
unsigned char* peer_id = NULL;
int peer_id_size = 0;
// This shouldn't be needed, but just in case:
message->provider_peer_head = NULL;
// Can I provide it locally?
struct DatastoreRecord* datastore_record = NULL;
if (protocol_context->datastore->datastore_get((unsigned char*)message->key, message->key_size, &datastore_record, protocol_context->datastore)) {
// we can provide this hash from our datastore
libp2p_datastore_record_free(datastore_record);
libp2p_logger_debug("dht_protocol", "I can provide myself as a provider for this key.\n");
message->provider_peer_head = libp2p_utils_linked_list_new();
message->provider_peer_head->item = libp2p_peer_copy(libp2p_peerstore_get_local_peer(protocol_context->peer_store));
} else if (libp2p_providerstore_get(protocol_context->provider_store, (unsigned char*)message->key, message->key_size, &peer_id, &peer_id_size)) {
// Can I provide it because someone announced it earlier?
// we have a peer id, convert it to a peer object
struct Libp2pPeer* peer = libp2p_peerstore_get_peer(protocol_context->peer_store, peer_id, peer_id_size);
if (peer != NULL) {
libp2p_logger_debug("dht_protocol", "I can provide a provider for this key, because %s says he has it.\n", libp2p_peer_id_to_string(peer));
// add it to the message
if (message->provider_peer_head == NULL) {
message->provider_peer_head = libp2p_utils_linked_list_new();
message->provider_peer_head->item = libp2p_peer_copy(peer);
} else {
struct Libp2pLinkedList* current = message->provider_peer_head;
// find the last one in the list
while (current->next != NULL) {
current = current->next;
}
// add to the list
current->next = libp2p_utils_linked_list_new();
current->next->item = peer;
}
}
} else {
size_t b58_size = 100;
uint8_t *b58key = (uint8_t *) malloc(b58_size);
if (!libp2p_crypto_encoding_base58_encode((unsigned char*)message->key, message->key_size, (unsigned char**)&b58key, &b58_size)) {
libp2p_logger_debug("dht_protocol", "I cannot provide a provider for this key.\n");
} else {
libp2p_logger_debug("dht_protocol", "I cannot provide a provider for the key %s.\n", b58key);
}
free(b58key);
}
if (peer_id != NULL)
free(peer_id);
// TODO: find closer peers
/*
if (message->provider_peer_head == NULL) {
// Who else can provide it?
//while ()
}
*/
if (message->provider_peer_head != NULL) {
libp2p_logger_debug("dht_protocol", "GetProviders: We have a peer. Sending it back.");
// protobuf it and send it back
if (!libp2p_routing_dht_protobuf_message(message, results, results_size)) {
libp2p_logger_error("dht_protocol", "GetProviders: Error protobufing results\n");
return 0;
}
}
return 1;
}
/***
* helper method to get ip multiaddress from peer's linked list
* @param head linked list of multiaddresses
* @returns the IP multiaddress in the list, or NULL if none found
*/
struct MultiAddress* libp2p_routing_dht_find_peer_ip_multiaddress(struct Libp2pLinkedList* head) {
struct MultiAddress* out = NULL;
struct Libp2pLinkedList* current = head;
while (current != NULL) {
out = (struct MultiAddress*)current->item;
if (multiaddress_is_ip(out)) {
//libp2p_logger_debug("dht_protocol", "Found MultiAddress %s\n", out->string);
break;
}
current = current->next;
}
if (current == NULL)
out = NULL;
return out;
}
/***
* Remote peer has announced that he can provide a key
* @param stream the incoming stream
* @param message the message
* @param protocol_context the context
* @param result_buffer where to put the result
* @param result_buffer_size the size of the result buffer
* @returns true(1) on success, otherwise false(0)
*/
int libp2p_routing_dht_handle_add_provider(struct Stream* stream, struct KademliaMessage* message,
struct DhtContext* protocol_context, unsigned char** result_buffer, size_t* result_buffer_size) {
int retVal = 0;
struct Libp2pPeer *peer = NULL;
//TODO: verify peer signature
if (libp2p_logger_watching_class("dht_protocol")) {
struct Libp2pPeer* first_peer = message->provider_peer_head->item;
libp2p_logger_debug("dht_protocol", "Peer %s says he can provide a key.\n", libp2p_peer_id_to_string(first_peer));
}
struct Libp2pLinkedList* current = message->provider_peer_head;
if (current == NULL) {
libp2p_logger_error("dht_protocol", "Provider has no peer.\n");
goto exit;
}
// there should only be 1 when adding a provider
if (current != NULL) {
peer = current->item;
if (peer == NULL) {
libp2p_logger_error("dht_protocol", "Message add_provider has no peer\n");
goto exit;
}
struct MultiAddress *peer_ma = libp2p_routing_dht_find_peer_ip_multiaddress(peer->addr_head);
if (peer_ma == NULL) {
libp2p_logger_error("dht_protocol", "Peer has no IP MultiAddress.\n");
goto exit;
}
// add what we know to be the ip for this peer
/*
char *ip;
char new_string[255];
multiaddress_get_ip_address(session->default_stream->address, &ip);
int port = multiaddress_get_ip_port(peer_ma);
char* peer_id = multiaddress_get_peer_id(peer_ma);
sprintf(new_string, "/ip4/%s/tcp/%d/ipfs/%s", ip, port, peer_id);
free(ip);
free(peer_id);
struct MultiAddress* new_ma = multiaddress_new_from_string(new_string);
if (new_ma == NULL)
goto exit;
// TODO: See if the sender is who he says he is
// set it as the first in the list
struct Libp2pLinkedList* new_head = libp2p_utils_linked_list_new();
new_head->item = new_ma;
new_head->next = peer->addr_head;
peer->addr_head = new_head;
*/
// now add the peer to the peerstore
libp2p_logger_debug("dht_protocol", "About to add peer %s to peerstore\n", peer_ma->string);
if (!libp2p_peerstore_add_peer(protocol_context->peer_store, peer))
goto exit;
libp2p_logger_debug("dht_protocol", "About to add key to providerstore\n");
if (!libp2p_providerstore_add(protocol_context->provider_store, (unsigned char*)message->key, message->key_size, (unsigned char*)peer->id, peer->id_size))
goto exit;
}
if (!libp2p_routing_dht_protobuf_message(message, result_buffer, result_buffer_size)) {
goto exit;
}
retVal = 1;
exit:
if (retVal != 1) {
if (*result_buffer != NULL) {
free(*result_buffer);
*result_buffer_size = 0;
*result_buffer = NULL;
}
libp2p_logger_error("dht_protocol", "add_provider returning false\n");
}
/*
if (peer != NULL)
libp2p_peer_free(peer);
*/
return retVal;
}
/**
* Retrieve something from the dht datastore
* @param session the session context
* @param message the message
* @param peerstore the peerstore
* @param providerstore the providerstore
* @param result_buffer the results, as a protobuf'd KademliaMessage
* @param result_buffer_size the size of the results
* @returns true(1) on success, otherwise false(0)
*/
int libp2p_routing_dht_handle_get_value(struct Stream* stream, struct KademliaMessage* message, struct DhtContext* dht_context,
unsigned char** result_buffer, size_t *result_buffer_size) {
struct Filestore* filestore = dht_context->filestore;
size_t data_size = 0;
unsigned char* data = NULL;
// We need to get the data from the disk
if(!filestore->node_get((unsigned char*)message->key, message->key_size, (void**)&data, &data_size, filestore)) {
size_t sz = 100;
unsigned char key[sz];
memset(key, 0, sz);
unsigned char* ptr = &key[0];
libp2p_crypto_encoding_base58_encode((unsigned char*)message->key, message->key_size, &ptr, &sz);
libp2p_logger_debug("dht_protocol", "handle_get_value: Unable to get key %s from filestore.\n", key);
return 0;
}
libp2p_logger_debug("dht_protocol", "handle_get_value: value retrieved from the datastore\n");
struct Libp2pRecord *record = libp2p_record_new();
record->key_size = message->key_size;
record->key = malloc(record->key_size);
memcpy(record->key, message->key, record->key_size);
record->value_size = data_size;
record->value = malloc(record->value_size);
memcpy(record->value, data, record->value_size);
message->record = record;
free(data);
if (!libp2p_routing_dht_protobuf_message(message, result_buffer, result_buffer_size)) {
libp2p_record_free(record);
message->record = NULL;
return 0;
}
return 1;
}
/**
* Put something in the dht datastore
* @param stream the incoming stream
* @param message the message
* @param peerstore the peerstore
* @param providerstore the providerstore
* @param datastore the datastore
* @returns true(1) on success, otherwise false(0)
*/
int libp2p_routing_dht_handle_put_value(struct Stream* stream, struct KademliaMessage* message,
struct DhtContext* protocol_context) {
if (message->record == NULL)
return 0;
struct DatastoreRecord* record = libp2p_datastore_record_new();
if (record == NULL)
return 0;
// set the key from the message->record->key
record->key_size = message->record->key_size;
record->key = (uint8_t*) malloc(record->key_size);
if (record->key == NULL) {
libp2p_datastore_record_free(record);
return 0;
}
memcpy(record->key, message->record->key, record->key_size);
// set the value from the message->record->value
record->value_size = message->record->value_size;
record->value = (uint8_t*) malloc(record->value_size);
if (record->value == NULL) {
libp2p_datastore_record_free(record);
return 0;
}
memcpy(record->value, message->record->value, record->value_size);
int retVal = protocol_context->datastore->datastore_put(record, protocol_context->datastore);
libp2p_datastore_record_free(record);
return retVal;
}
/**
* Find a node
* @param session the session context
* @param message the message
* @param peerstore the peerstore
* @param providerstore the providerstore
* @param result_buffer the results
* @param result_buffer_size the size of the results
* @returns true(1) on success, otherwise false(0)
*/
int libp2p_routing_dht_handle_find_node(struct Stream* stream, struct KademliaMessage* message,
struct DhtContext* protocol_context, unsigned char** result_buffer, size_t *result_buffer_size) {
// look through peer store
struct Libp2pPeer* peer = libp2p_peerstore_get_peer(protocol_context->peer_store, (unsigned char*)message->key, message->key_size);
if (peer != NULL) {
message->provider_peer_head = libp2p_utils_linked_list_new();
message->provider_peer_head->item = libp2p_peer_copy(peer);
if (!libp2p_routing_dht_protobuf_message(message, result_buffer, result_buffer_size)) {
return 0;
}
return 1;
}
return 0;
}
/***
* Handle the incoming message. Handshake should have already
* been done. We should expect that the next read contains
* a protobuf'd kademlia message.
* @param session the context
* @param peerstore a list of peers
* @returns true(1) on success, otherwise false(0)
*/
int libp2p_routing_dht_handle_message(struct Stream* stream, struct DhtContext* protocol_context) {
unsigned char *result_buffer = NULL;
struct StreamMessage* buffer = NULL;
size_t result_buffer_size = 0;
int retVal = 0;
struct KademliaMessage* message = NULL;
// read from stream
if (!stream->read(stream->stream_context, &buffer, 5))
goto exit;
// unprotobuf
if (!libp2p_message_protobuf_decode(buffer->data, buffer->data_size, &message))
goto exit;
// handle message
switch(message->message_type) {
case(MESSAGE_TYPE_PUT_VALUE): // store a value in local storage
libp2p_routing_dht_handle_put_value(stream, message, protocol_context);
break;
case(MESSAGE_TYPE_GET_VALUE): // get a value from local storage
libp2p_routing_dht_handle_get_value(stream, message, protocol_context, &result_buffer, &result_buffer_size);
break;
case(MESSAGE_TYPE_ADD_PROVIDER): // client wants us to know he can provide something
libp2p_routing_dht_handle_add_provider(stream, message, protocol_context, &result_buffer, &result_buffer_size);
break;
case(MESSAGE_TYPE_GET_PROVIDERS): // see if we can help, and send closer peers
libp2p_routing_dht_handle_get_providers(stream, message, protocol_context, &result_buffer, &result_buffer_size);
break;
case(MESSAGE_TYPE_FIND_NODE): // find peers
libp2p_routing_dht_handle_find_node(stream, message, protocol_context, &result_buffer, &result_buffer_size);
break;
case(MESSAGE_TYPE_PING):
libp2p_routing_dht_handle_ping(message, &result_buffer, &result_buffer_size);
break;
}
// if we have something to send, send it.
if (result_buffer != NULL) {
libp2p_logger_debug("dht_protocol", "Sending message back to caller. Message type: %d\n", message->message_type);
struct StreamMessage outgoing;
outgoing.data = result_buffer;
outgoing.data_size = result_buffer_size;
if (!stream->write(stream->stream_context, &outgoing))
goto exit;
} else {
libp2p_logger_debug("dht_protocol", "DhtHandleMessage: Nothing to send back. Kademlia call has been handled. Message type: %d\n", message->message_type);
}
retVal = 1;
exit:
libp2p_stream_message_free(buffer);
if (result_buffer != NULL)
free(result_buffer);
if (message != NULL)
libp2p_message_free(message);
return retVal;
}
/**
* Attempt to receive a kademlia message
* NOTE: This call assumes that a send_message was sent
* @param sessionContext the context
* @param result where to put the results
* @returns true(1) on success, false(0) otherwise
*/
int libp2p_routing_dht_receive_message(struct SessionContext* sessionContext, struct KademliaMessage** result) {
struct StreamMessage* results = NULL;
if (!sessionContext->default_stream->read(sessionContext, &results, 5)) {
libp2p_logger_error("online", "Attempted to read from Kademlia stream, but could not.\n");
goto exit;
}
// see if we can unprotobuf
if (!libp2p_message_protobuf_decode(results->data, results->data_size, result)) {
libp2p_logger_error("online", "Received kademlia response, but cannot decode it.\n");
goto exit;
}
exit:
libp2p_stream_message_free(results);
return result != NULL;
}
/***
* Send a kademlia message
* NOTE: this call upgrades the stream to /ipfs/kad/1.0.0
* @param context the context
* @param message the message
* @returns true(1) on success, false(0) otherwise
*/
int libp2p_routing_dht_send_message(struct SessionContext* sessionContext, struct KademliaMessage* message) {
size_t protobuf_size = 0, retVal = 0;
unsigned char* protobuf = NULL;
struct StreamMessage outgoing;
protobuf_size = libp2p_message_protobuf_encode_size(message);
protobuf = (unsigned char*)malloc(protobuf_size);
libp2p_message_protobuf_encode(message, &protobuf[0], protobuf_size, &protobuf_size);
// upgrade to kademlia protocol
if (!libp2p_routing_dht_upgrade_stream(sessionContext)) {
libp2p_logger_error("dht_protocol", "send_message: Unable to upgrade to kademlia stream.\n");
goto exit;
}
// send the message
outgoing.data = protobuf;
outgoing.data_size = protobuf_size;
if (!sessionContext->default_stream->write(sessionContext, &outgoing)) {
libp2p_logger_error("dht_protocol", "send_message: Attempted to write to Kademlia stream, but could not.\n");
goto exit;
}
retVal = 1;
exit:
if (protobuf != NULL)
free(protobuf);
return retVal;
}
/**
* Used to send a message to the nearest x peers
*
* @param private_key the private key of the local peer
* @param peerstore the collection of peers
* @param datastore a connection to the datastore
* @param msg the message to send
* @returns true(1) if we sent to at least 1, false(0) otherwise
*/
int libp2p_routing_dht_send_message_nearest_x(const struct Dialer* dialer, struct Peerstore* peerstore,
struct Datastore* datastore, struct KademliaMessage* msg, int numToSend) {
// TODO: Calculate "Nearest"
// but for now, grab x peers, and send to them
int numSent = 0;
struct Libp2pLinkedList* llpeer_entry = peerstore->head_entry;
while (llpeer_entry != NULL) {
struct PeerEntry* entry = llpeer_entry->item;
if (entry == NULL)
break;
struct Libp2pPeer* remote_peer = entry->peer;
if (!remote_peer->is_local) {
// connect (if not connected)
if (libp2p_peer_connect(dialer, remote_peer, peerstore, datastore, 5)) {
// send message
if (libp2p_routing_dht_send_message(remote_peer->sessionContext, msg))
numSent++;
}
if (numSent >= numToSend)
break;
}
// grab next entry
llpeer_entry = llpeer_entry->next;
}
return numSent > 0;
}
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