c-libp2p/net/multistream.c

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#include <stdlib.h>
#include <unistd.h>
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#include <stdio.h>
#include <string.h>
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#include <errno.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "libp2p/net/p2pnet.h"
#include "libp2p/record/message.h"
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#include "libp2p/secio/secio.h"
#include "varint.h"
#include "libp2p/net/multistream.h"
#include "multiaddr/multiaddr.h"
/***
* An implementation of the libp2p multistream
*/
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int libp2p_net_multistream_close(void* stream_context) {
struct SessionContext* secure_context = (struct SessionContext*)stream_context;
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struct Stream* stream = secure_context->insecure_stream;
close((intptr_t)stream->socket_descriptor);
return 1;
}
/**
* Write to an open multistream host
* @param socket_fd the socket file descriptor
* @param data the data to send
* @param data_length the length of the data
* @returns the number of bytes written
*/
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int libp2p_net_multistream_write(void* stream_context, const unsigned char* data, size_t data_length) {
struct SessionContext* secure_context = (struct SessionContext*)stream_context;
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struct Stream* stream = secure_context->insecure_stream;
int num_bytes = 0;
if (data_length > 0) { // only do this is if there is something to send
// first send the size
unsigned char varint[12];
size_t varint_size = 0;
varint_encode(data_length, &varint[0], 12, &varint_size);
num_bytes = socket_write(*((int*)stream->socket_descriptor), (char*)varint, varint_size, 0);
if (num_bytes == 0)
return 0;
// then send the actual data
num_bytes += socket_write(*((int*)stream->socket_descriptor), (char*)data, data_length, 0);
}
return num_bytes;
}
/**
* Read from a multistream socket
* @param socket_fd the socket file descriptor
* @param results where to put the results. NOTE: this memory is allocated
* @param results_size the size of the results in bytes
* @returns number of bytes received
*/
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int libp2p_net_multistream_read(void* stream_context, unsigned char** results, size_t* results_size) {
struct SessionContext* secure_context = (struct SessionContext*)stream_context;
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struct Stream* stream = secure_context->insecure_stream;
int bytes = 0;
size_t buffer_size = 65535;
char buffer[buffer_size];
char* pos = buffer;
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size_t num_bytes_requested = 0, left = 0, already_read = 0;
// first read the varint
while(1) {
unsigned char c;
bytes = socket_read(*((int*)stream->socket_descriptor), (char*)&c, 1, 0);
pos[0] = c;
if (c >> 7 == 0) {
pos[1] = 0;
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num_bytes_requested = varint_decode((unsigned char*)buffer, strlen(buffer), NULL);
break;
}
pos++;
}
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if (num_bytes_requested <= 0)
return 0;
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left = num_bytes_requested;
do {
bytes = socket_read(*((int*)stream->socket_descriptor), &buffer[already_read], left, 0);
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if (bytes < 0) {
bytes = 0;
if ( (errno == EAGAIN) || (errno == EWOULDBLOCK)) {
// do something intelligent
} else {
return 0;
}
}
left = left - bytes;
already_read += bytes;
} while (left > 0);
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if (already_read != num_bytes_requested)
return 0;
// parse the results, removing the leading size indicator
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*results = malloc(num_bytes_requested);
if (*results == NULL)
return 0;
memcpy(*results, buffer, num_bytes_requested);
*results_size = num_bytes_requested;
return num_bytes_requested;
}
/**
* Connect to a multistream host, and this includes the multistream handshaking.
* @param hostname the host
* @param port the port
* @returns the socket file descriptor of the connection, or -1 on error
*/
struct Stream* libp2p_net_multistream_connect(const char* hostname, int port) {
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int retVal = -1, return_result = -1, socket = -1;
unsigned char* results = NULL;
size_t results_size;
size_t num_bytes = 0;
struct Stream* stream = NULL;
uint32_t ip = hostname_to_ip(hostname);
socket = socket_open4();
// connect
if (socket_connect4(socket, ip, port) != 0)
goto exit;
// send the multistream handshake
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char* protocol_buffer = "/multistream/1.0.0\n";
stream = libp2p_net_multistream_stream_new(socket, hostname, port);
if (stream == NULL)
goto exit;
struct SessionContext session;
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session.insecure_stream = stream;
session.default_stream = stream;
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// try to receive the protocol id
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return_result = libp2p_net_multistream_read(&session, &results, &results_size);
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if (return_result == 0 || results_size < 1)
goto exit;
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num_bytes = libp2p_net_multistream_write(&session, (unsigned char*)protocol_buffer, strlen(protocol_buffer));
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if (num_bytes <= 0)
goto exit;
if (strstr((char*)results, "multistream") == NULL)
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goto exit;
// we are now in the loop, so we can switch to another protocol (i.e. /secio/1.0.0)
retVal = socket;
exit:
if (results != NULL)
free(results);
if (retVal < 0 && stream != NULL) {
libp2p_net_multistream_stream_free(stream);
stream = NULL;
}
return stream;
}
int libp2p_net_multistream_negotiate(struct Stream* stream) {
const char* protocolID = "/multistream/1.0.0\n";
unsigned char* results = NULL;
size_t results_length = 0;
int retVal = 0;
// send the protocol id
struct SessionContext secure_session;
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secure_session.insecure_stream = stream;
secure_session.default_stream = stream;
if (!libp2p_net_multistream_write(&secure_session, (unsigned char*)protocolID, strlen(protocolID)))
goto exit;
// expect the same back
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libp2p_net_multistream_read(&secure_session, &results, &results_length);
if (results_length == 0)
goto exit;
if (strncmp((char*)results, protocolID, strlen(protocolID)) != 0)
goto exit;
retVal = 1;
exit:
if (results != NULL)
free(results);
return retVal;
}
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/**
* Expect to read a message
* @param fd the socket file descriptor
* @returns the retrieved message, or NULL
*/
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/*
struct Libp2pMessage* libp2p_net_multistream_get_message(struct Stream* stream) {
int retVal = 0;
unsigned char* results = NULL;
size_t results_size = 0;
struct Libp2pMessage* msg = NULL;
// read what they sent
libp2p_net_multistream_read(stream, &results, &results_size);
// unprotobuf it
if (!libp2p_message_protobuf_decode(results, results_size, &msg))
goto exit;
// clean up
retVal = 1;
exit:
if (results != NULL)
free(results);
if (retVal != 1 && msg != NULL)
libp2p_message_free(msg);
return msg;
}
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*/
void libp2p_net_multistream_stream_free(struct Stream* stream) {
if (stream != NULL) {
if (stream->socket_descriptor != NULL)
free(stream->socket_descriptor);
if (stream->address != NULL)
multiaddress_free(stream->address);
free(stream);
}
}
/**
* Create a new MultiStream structure
* @param socket_fd the file descriptor
* @param ip the IP address
* @param port the port
*/
struct Stream* libp2p_net_multistream_stream_new(int socket_fd, const char* ip, int port) {
struct Stream* out = (struct Stream*)malloc(sizeof(struct Stream));
if (out != NULL) {
out->socket_descriptor = malloc(sizeof(int));
*((int*)out->socket_descriptor) = socket_fd;
int res = *((int*)out->socket_descriptor);
if (res != socket_fd) {
libp2p_net_multistream_stream_free(out);
return NULL;
}
out->close = libp2p_net_multistream_close;
out->read = libp2p_net_multistream_read;
out->write = libp2p_net_multistream_write;
char str[strlen(ip) + 50];
sprintf(str, "/ip4/%s/tcp/%d", ip, port);
out->address = multiaddress_new_from_string(str);
}
return out;
}