c-libp2p/routing/dht_protocol.c

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#include <stdlib.h>
#include <string.h>
#include "libp2p/net/stream.h"
#include "libp2p/routing/dht_protocol.h"
#include "libp2p/record/message.h"
#include "libp2p/utils/logger.h"
#include "libp2p/conn/session.h"
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/***
* This is where kademlia and dht talk to the outside world
*/
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/***
* 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 Libp2pMessage* 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;
}
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/**
* 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";
unsigned char* results = NULL;
size_t results_size = 0;
if (!context->default_stream->write(context, (unsigned char*)protocol, strlen(protocol)))
goto exit;
if (!context->default_stream->read(context, &results, &results_size, 5))
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goto exit;
if (results_size != strlen(protocol))
goto exit;
if (strncmp((char*)results, protocol, results_size) != 0)
goto exit;
retVal = 1;
exit:
if (results != NULL) {
free(results);
results = NULL;
}
return retVal;
}
/**
* Handle a client requesting an upgrade to the DHT protocol
* @param context the context
* @returns true(1) on success, otherwise false(0)
*/
int libp2p_routing_dht_handshake(struct SessionContext* context) {
char* protocol = "/ipfs/kad/1.0.0\n";
return context->default_stream->write(context, (unsigned char*)protocol, strlen(protocol));
}
/**
* 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 Libp2pMessage* message, unsigned char** buffer, size_t *buffer_size) {
// just turn message back into a protobuf and send it back...
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return libp2p_routing_dht_protobuf_message(message, buffer, buffer_size);
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}
/**
* See if we have information as to who can provide this item
* @param session the context
* @param message the message from the caller, contains a key
* @param peerstore the list of peers
* @param providerstore the list of peers that can provide things
* @returns true(1) on success, false(0) otherwise
*/
int libp2p_routing_dht_handle_get_providers(struct SessionContext* session, struct Libp2pMessage* message, struct Peerstore* peerstore,
struct ProviderStore* providerstore, 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?
if (libp2p_providerstore_get(providerstore, message->key, message->key_size, &peer_id, &peer_id_size)) {
libp2p_logger_debug("dht_protocol", "I can provide a provider for this key.\n");
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// we have a peer id, convert it to a peer object
struct Libp2pPeer* peer = libp2p_peerstore_get_peer(peerstore, peer_id, peer_id_size);
if (peer != NULL) {
message->provider_peer_head = libp2p_utils_linked_list_new();
message->provider_peer_head->item = libp2p_peer_copy(peer);
}
} else {
libp2p_logger_debug("dht_protocol", "I cannot provide a provider for this key.\n");
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}
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\n");
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// protobuf it and send it back
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if (!libp2p_routing_dht_protobuf_message(message, results, results_size)) {
libp2p_logger_error("dht_protocol", "GetProviders: Error protobufing results\n");
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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;
}
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/***
* Remote peer has announced that he can provide a key
* @param session session context
* @param message the message
* @param peerstore the peerstore
* @param providerstore the providerstore
* @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 SessionContext* session, struct Libp2pMessage* message,
struct Peerstore* peerstore, struct ProviderStore* providerstore, unsigned char** result_buffer, size_t* result_buffer_size) {
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int retVal = 0;
struct Libp2pPeer *peer = NULL;
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//TODO: verify peer signature
/*
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if (message->record != NULL && message->record->author != NULL && message->record->author_size > 0
&& message->key != NULL && message->key_size > 0)
*/
struct Libp2pLinkedList* current = message->provider_peer_head;
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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);
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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);
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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;
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libp2p_logger_debug("dht_protocol", "New MultiAddress made with %s.\n", new_string);
// 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);
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if (!libp2p_peerstore_add_peer(peerstore, peer))
goto exit;
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libp2p_logger_debug("dht_protocol", "About to add key to providerstore\n");
if (!libp2p_providerstore_add(providerstore, message->key, message->key_size, peer->id, peer->id_size))
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goto exit;
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}
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if (!libp2p_routing_dht_protobuf_message(message, result_buffer, result_buffer_size)) {
goto exit;
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}
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retVal = 1;
exit:
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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");
}
/*
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if (peer != NULL)
libp2p_peer_free(peer);
*/
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return retVal;
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}
/**
* 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
* @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 SessionContext* session, struct Libp2pMessage* message,
struct Peerstore* peerstore, struct ProviderStore* providerstore, unsigned char** result_buffer, size_t *result_buffer_size) {
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struct Datastore* datastore = session->datastore;
struct Filestore* filestore = session->filestore;
size_t data_size = 0;
unsigned char* data = NULL;
// We need to get the data from the disk
if(!filestore->node_get(message->key, message->key_size, (void**)&data, &data_size, filestore)) {
libp2p_logger_debug("dht_protocol", "handle_get_value: Unable to get key from filestore\n");
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}
libp2p_logger_debug("dht_protocol", "handle_get_value: value retrieved from the datastore\n");
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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;
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}
/**
* Put something in 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
* @param result_buffer_size the size of the results
* @returns true(1) on success, otherwise false(0)
*/
int libp2p_routing_dht_handle_put_value(struct SessionContext* session, struct Libp2pMessage* message,
struct Peerstore* peerstore, struct ProviderStore* providerstore, unsigned char** result_buffer, size_t *result_buffer_size) {
//TODO: implement this
return 0;
}
/**
* 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 SessionContext* session, struct Libp2pMessage* message,
struct Peerstore* peerstore, struct ProviderStore* providerstore, unsigned char** result_buffer, size_t *result_buffer_size) {
// look through peer store
struct Libp2pPeer* peer = libp2p_peerstore_get_peer(peerstore, message->key, message->key_size);
if (peer != NULL) {
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message->provider_peer_head = libp2p_utils_linked_list_new();
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message->provider_peer_head->item = libp2p_peer_copy(peer);
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if (!libp2p_routing_dht_protobuf_message(message, result_buffer, result_buffer_size)) {
return 0;
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}
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return 1;
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}
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 SessionContext* session, struct Peerstore* peerstore, struct ProviderStore* providerstore) {
unsigned char* buffer = NULL, *result_buffer = NULL;
size_t buffer_size = 0, result_buffer_size = 0;
int retVal = 0;
struct Libp2pMessage* message = NULL;
// read from stream
if (!session->default_stream->read(session, &buffer, &buffer_size, 5))
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goto exit;
// unprotobuf
if (!libp2p_message_protobuf_decode(buffer, buffer_size, &message))
goto exit;
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// handle message
switch(message->message_type) {
case(MESSAGE_TYPE_PUT_VALUE): // store a value in local storage
libp2p_routing_dht_handle_put_value(session, message, peerstore, providerstore, &result_buffer, &result_buffer_size);
break;
case(MESSAGE_TYPE_GET_VALUE): // get a value from local storage
libp2p_routing_dht_handle_get_value(session, message, peerstore, providerstore, &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(session, message, peerstore, providerstore, &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(session, message, peerstore, providerstore, &result_buffer, &result_buffer_size);
break;
case(MESSAGE_TYPE_FIND_NODE): // find peers
libp2p_routing_dht_handle_find_node(session, message, peerstore, providerstore, &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.
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if (result_buffer != NULL) {
libp2p_logger_debug("dht_protocol", "Sending message back to caller. Message type: %d\n", message->message_type);
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if (!session->default_stream->write(session, result_buffer, result_buffer_size))
goto exit;
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} else {
libp2p_logger_debug("dht_protocol", "DhtHandleMessage: Nothing to send back. Kademlia call has been handled. Message type: %d\n", message->message_type);
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}
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retVal = 1;
exit:
if (buffer != NULL)
free(buffer);
if (result_buffer != NULL)
free(result_buffer);
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if (message != NULL)
libp2p_message_free(message);
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return retVal;
}