/**
* Performs the same function as getipbyname(),
* except that it will prevent extremely expensive net_gethostbyname() calls by caching the result
*/
u32 getipbynamecached(char *domain)
{
//Search if this domainname is already cached
struct dnsentry *node = firstdnsentry;
struct dnsentry *previousnode = NULL;
while(node != NULL)
{
if(strcmp(node->domain, domain) == 0)
{
//DNS node found in the cache, move it to the front of the list
if(previousnode != NULL)
previousnode->nextnode = node->nextnode;
if(node != firstdnsentry)
node->nextnode = firstdnsentry;
firstdnsentry = node;
return node->ip;
}
//Go to the next element in the list
previousnode = node;
node = node->nextnode;
}
u32 ip = getipbyname(domain);
//No cache of this domain could be found, create a cache node and add it to the front of the cache
struct dnsentry *newnode = malloc(sizeof(struct dnsentry));
if(newnode == NULL) return ip;
newnode->ip = ip;
newnode->domain = malloc(strlen(domain)+1);
if(newnode->domain == NULL)
{
free(newnode);
return ip;
}
strcpy(newnode->domain, domain);
newnode->nextnode = firstdnsentry;
firstdnsentry = newnode;
dnsentrycount++;
//If the cache grows too big delete the last (and probably least important) node of the list
if(dnsentrycount > MAX_DNS_CACHE_ENTRIES)
{
struct dnsentry *node = firstdnsentry;
struct dnsentry *previousnode = NULL;
//Fetch the last two elements of the list
while(node->nextnode != NULL)
{
previousnode = node;
node = node->nextnode;
}
if(node == NULL)
{
printf("Configuration error, MAX_DNS_ENTRIES reached while the list is empty\n");
exit(1);
} else if(previousnode == NULL)
{
firstdnsentry = NULL;
} else {
previousnode->nextnode = NULL;
}
free(node->domain);
free(node);
dnsentrycount--;
}
return newnode->ip;
}
/**
* 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)
{
sprintf(emptyblock.error,TX.URLnoBegin, url); //doen't start with http://
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)
{
sprintf(emptyblock.error,TX.URLnoPath, url); //no path part in URL
return emptyblock;
}
//Extract the domain part out of the url
int domainlength = path - url - strlen("http://");
if(domainlength == 0)
{
sprintf(emptyblock.error,TX.URLnoDomain, url); //couldn't find a domain in url
return emptyblock;
}
char domain[domainlength + 1];
strncpy(domain, url + strlen("http://"), domainlength);
domain[domainlength] = '\0';
//Parsing of the URL is done, start making an actual connection
u32 ipaddress = getipbyname(domain); //slower but doesn't leak memory
if(ipaddress == 0)
{
sprintf(emptyblock.error,TX.errorDomain, domain); //couldn't resolve domain
return emptyblock;
}
s32 connection = server_connect(ipaddress, 80);
if(connection < 0) {
sprintf(emptyblock.error,TX.errEstablishConn); //couldn't establish connection
return emptyblock;
}
//Form a nice request header to send to the webserver
char* headerformat = "GET %s HTTP/1.0\r\nHost: %s\r\nUser-Agent: WiiEarthh 1.0\r\n\r\n";;
char header[strlen(headerformat) + strlen(domain) + strlen(path)];
sprintf(header, headerformat, path, domain);
//Do the request and get the response
send_message(connection, header);
struct block response = read_message(connection);
net_close(connection);
//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;
int i;
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;
break;
}
}
if(filestart == NULL)
{
sprintf(emptyblock.error,TX.HTTPnoFile);
return emptyblock;
}
//Copy the file part of the response into a new memoryblock to return
struct block file;
file.data = CFMalloc(filesize);
file.size = filesize;
if(file.data == NULL)
{
sprintf(emptyblock.error,TX.noMemCopy ); //couldn't copy the file to the block
CFFree(response.data);
return emptyblock;
}
memcpy(file.data, filestart, filesize);
//Dispose of the original response
CFFree(response.data);
return file;
}
