usbloadergx/source/network/http.c

/*  http -- http convenience functions

    Copyright (C) 2008 bushing
				  2008-2014 Dimok, Cyan

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, version 2.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "http.h"
#include "../svnrev.h"
#include "gecko.h"

extern char incommingIP[50];
static u8 retryloop = 0;

/**
 * Emptyblock is a statically defined variable for functions to return if they are unable
 * to complete a request
 */
const struct block emptyblock = { 0, NULL };

//The maximum amount of bytes to send per net_write() call
//#define NET_BUFFER_SIZE 1024
#define NET_BUFFER_SIZE 3600

// Write our message to the server
static s32 send_message(s32 server, char *msg)
{
	s32 bytes_transferred = 0;
	s32 remaining = strlen(msg);
	while (remaining)
	{
		if ((bytes_transferred = net_write(server, msg, remaining > NET_BUFFER_SIZE ? NET_BUFFER_SIZE : remaining)) > 0)
		{
			remaining -= bytes_transferred;
			msg += bytes_transferred;
			usleep(20 * 1000);
		}
		else if (bytes_transferred < 0)
		{
			return bytes_transferred;
		}
		else
		{
			return -ENODATA;
		}
	}
	return 0;
}

/**
 * Connect to a remote server via TCP on a specified port
 *
 * @param u32 ip address of the server to connect to
 * @param u32 the port to connect to on the server
 * @return s32 The connection to the server (negative number if connection could not be established)
 */
static s32 server_connect(u32 ipaddress, u16 socket_port)
{
	//Initialize socket
	s32 connection = net_socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
	if (connection < 0) return connection;

	struct sockaddr_in connect_addr;
	memset(&connect_addr, 0, sizeof(connect_addr));
	connect_addr.sin_family = AF_INET;
	connect_addr.sin_port = htons(socket_port);
	connect_addr.sin_addr.s_addr = ipaddress;

	sprintf(incommingIP, "%s", inet_ntoa(connect_addr.sin_addr));

	//Attemt to open the socket
	if (net_connect(connection, (struct sockaddr*) &connect_addr, sizeof(connect_addr)) == -1)
	{
		net_close(connection);
		return -1;
	}
	return connection;
}

//The amount of memory in bytes reserved initially to store the HTTP response in
//Be careful in increasing this number, reading from a socket on the Wii
//will fail if you request more than 20k or so
#define HTTP_BUFFER_SIZE 1024 * 5

//The amount of memory the buffer should expanded with if the buffer is full
#define HTTP_BUFFER_GROWTH 1024 * 5

/**
 * This function reads all the data from a connection into a buffer which it returns.
 * It will return an empty buffer if something doesn't go as planned
 *
 * @param s32 connection The connection identifier to suck the response out of
 * @return block A 'block' struct (see http.h) in which the buffer is located
 */
struct block read_message(s32 connection)
{
	//Create a block of memory to put in the response
	struct block buffer;
	buffer.data = malloc(HTTP_BUFFER_SIZE);
	buffer.size = HTTP_BUFFER_SIZE;

	if (buffer.data == NULL)
	{
		return emptyblock;
	}

	//The offset variable always points to the first byte of memory that is free in the buffer
	u32 offset = 0;

	while (1)
	{
		//Fill the buffer with a new batch of bytes from the connection,
		//starting from where we left of in the buffer till the end of the buffer
		s32 bytes_read = net_read(connection, buffer.data + offset, buffer.size - offset);

		//Anything below 0 is an error in the connection
		if (bytes_read < 0)
		{
			//printf("Connection error from net_read()  Errorcode: %i\n", bytes_read);
			return emptyblock;
		}

		//No more bytes were read into the buffer,
		//we assume this means the HTTP response is done
		if (bytes_read == 0)
		{
			break;
		}

		offset += bytes_read;

		//Check if we have enough buffer left over,
		//if not expand it with an additional HTTP_BUFFER_GROWTH worth of bytes
		if (offset >= buffer.size)
		{
			buffer.size += HTTP_BUFFER_GROWTH;
			u8 * tmp = realloc(buffer.data, buffer.size);

			if (tmp == NULL)
			{
				free(buffer.data);
				return emptyblock;
			}
			else
				buffer.data = tmp;
		}
	}

	//At the end of above loop offset should be precisely the amount of bytes that were read from the connection
	buffer.size = offset;

	//Shrink the size of the buffer so the data fits exactly in it
	buffer.data = realloc(buffer.data, buffer.size);

	return buffer;
}

/**
 * Downloads the contents of a URL to memory
 * This method is not threadsafe (because networking is not threadsafe on the Wii)
 */
struct block downloadfile(const char *url)
{
	//Check if the url starts with "http://", if not it is not considered a valid url
	if (strncmp(url, "http://", strlen("http://")) != 0)
	{
		//printf("URL '%s' doesn't start with 'http://'\n", url);
		return emptyblock;
	}

	//Locate the path part of the url by searching for '/' past "http://"
	char *path = strchr(url + strlen("http://"), '/');

	//At the very least the url has to end with '/', ending with just a domain is invalid
	if (path == NULL)
	{
		//printf("URL '%s' has no PATH part\n", url);
		return emptyblock;
	}

	//Extract the domain part out of the url
	int domainlength = path - url - strlen("http://");

	if (domainlength == 0)
	{
		//printf("No domain part in URL '%s'\n", url);
		return emptyblock;
	}

	char domain[domainlength + 1];
	strlcpy(domain, url + strlen("http://"), domainlength + 1);

	//Parsing of the URL is done, start making an actual connection
	u32 ipaddress = getipbynamecached(domain);

	if (ipaddress == 0)
	{
		//printf("\ndomain %s could not be resolved", domain);
		return emptyblock;
	}

	s32 connection = server_connect(ipaddress, 80);

	if (connection < 0)
	{
		//printf("Error establishing connection");
		return emptyblock;
	}

	// Remove Referer from the request header for incompatible websites (ex. Cloudflare proxy)
	char referer[domainlength + 12];
	snprintf(referer, sizeof(referer), "Referer: %s\r\n", domain);
	if(strstr(url, "geckocodes"))
	{
		strcpy(referer, "");
	}

	//Form a nice request header to send to the webserver
	char* headerformat = "GET %s HTTP/1.0\r\nHost: %s\r\n%sUser-Agent: USBLoaderGX r%s\r\n\r\n";
	char header[strlen(headerformat) + strlen(path) + strlen(domain) + strlen(referer) + 100];
	sprintf(header, headerformat, path, domain, referer, GetRev());
	//gprintf("\nHTTP Request:\n");
	//gprintf("%s\n",header);

	//Do the request and get the response
	send_message(connection, header);
	struct block response = read_message(connection);
	net_close(connection);
	
	// dump response
	// hexdump(response.data, response.size);
	
	//Search for the 4-character sequence \r\n\r\n in the response which signals the start of the http payload (file)
	unsigned char *filestart = NULL;
	u32 filesize = 0;
	u32 i;
	char newURL[512];
	bool redirect = false;

	for (i = 3; i < response.size; i++)
	{
		if (response.data[i] == '\n' && response.data[i - 1] == '\r' && response.data[i - 2] == '\n' && response.data[i - 3] == '\r')
		{
			filestart = response.data + i + 1;
			filesize = response.size - i - 1;
			
			// Check the HTTP response code
			if (response.size > 10 && strncmp((char*)response.data, "HTTP/", 5)==0) 
			{
				char htstat[i];
				strncpy(htstat, (char*)response.data, i);
				htstat[i] = 0;
				char *codep;
				codep = strchr(htstat, ' ');
				if (codep) 
				{
					int code;
					if (sscanf(codep+1, "%d", &code) == 1) 
					{
						//gprintf("HTTP response code: %d\n", code);
						if (code == 302) // 302 FOUND (redirected link)
						{
							char *ptr = strcasestr((char*)response.data, "Location: ");
							if(ptr)
							{
								ptr += strlen("Location: ");
								strncpy(newURL, ptr, sizeof(newURL));
								*(strchr(newURL, '\r'))=0;
								
								redirect = true;
								//gprintf("New URL to download = %s \n", newURL);
							}
							else
							{
								//gprintf("HTTP ERROR: %s\n", htstat);
								free(response.data);
								return emptyblock;
							}
						}
						if (code >=400) // Not found
						{
							//gprintf("HTTP ERROR: %s\n", htstat);
							free(response.data);
							return emptyblock;
						}
					}
				}
			}
			break;
		}
	}

	if(redirect)
	{
		// Prevent endless loop
		retryloop++;
		if(retryloop > 3)
		{
			retryloop = 0;
			free(response.data);
			return emptyblock;
		}
		
		struct block redirected = downloadfile(newURL);

		// copy the newURL data into the original data
		u8 * tmp = realloc(response.data, redirected.size);
		if (tmp == NULL)
		{
			//gprintf("Could not allocate enough memory for new URL. Download canceled.\n");
			free(response.data);
			free(redirected.data);
			return emptyblock;
		}
		response.data = tmp;
		memcpy(response.data, redirected.data, redirected.size);

		// Set filestart's new size based on redirected file
		filestart = response.data;
		filesize = redirected.size;
		free(redirected.data);
		
	}
	retryloop = 0;

	if (filestart == NULL)
	{
		//printf("HTTP Response was without a file\n");
		free(response.data);
		return emptyblock;
	}

	//Copy the file part of the response into a new memoryblock to return
	struct block file;
	file.data = malloc(filesize);
	file.size = filesize;

	if (file.data == NULL)
	{
		//printf("No more memory to copy file from HTTP response\n");
		free(response.data);
		return emptyblock;
	}

	memcpy(file.data, filestart, filesize);

	//Dispose of the original response
	free(response.data);

	return file;
}

s32 GetConnection(char * domain)
{

	u32 ipaddress = getipbynamecached(domain);
	if (ipaddress == 0)
	{
		return -1;
	}
	s32 connection = server_connect(ipaddress, 80);
	return connection;

}