opentracker/opentracker.c

#include "socket.h"
#include "io.h"
#include "buffer.h"
#include "ip6.h"
#include "array.h"
#include "case.h"
#include "fmt.h"
#include "iob.h"
#include "str.h"
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>

static void carp(const char* routine) {
  buffer_puts(buffer_2,routine);
  buffer_puts(buffer_2,": ");
  buffer_puterror(buffer_2);
  buffer_putnlflush(buffer_2);
}

static void panic(const char* routine) {
  carp(routine);
  exit(111);
}

struct http_data {
  array r;
  io_batch iob;
  char* hdrbuf;
  int hlen;
  char ip[16];
};

int header_complete(struct http_data* r)
{
	long i;

	long l = array_bytes(&r->r);
	const char* c = array_start(&r->r);

	for (i=0; i+1<l; ++i)
	{
		if (c[i]=='\n' && c[i+1]=='\n')
			return i+2;

		if (i+3<l && c[i]=='\r' && c[i+1]=='\n' && c[i+2]=='\r' && c[i+3]=='\n')
			return i+4;
	}
	return 0;
}

void httperror(struct http_data* r,const char* title,const char* message)
{
	char* c;
	c=r->hdrbuf=(char*)malloc(strlen(message)+strlen(title)+200);
	
	if (!c)
	{
		r->hdrbuf="HTTP/1.0 500 internal error\r\nContent-Type: text/plain\r\nConnection: close\r\n\r\nout of memory\n";
		r->hlen=strlen(r->hdrbuf);
	}
	else
	{
		c+=fmt_str(c,"HTTP/1.0 ");
		c+=fmt_str(c,title);
		c+=fmt_str(c,"\r\nContent-Type: text/html\r\nConnection: close\r\nContent-Length: ");
		c+=fmt_ulong(c,strlen(message)+strlen(title)+16-4);
		c+=fmt_str(c,"\r\n\r\n<title>");
		c+=fmt_str(c,title+4);
		c+=fmt_str(c,"</title>\n");
		r->hlen=c - r->hdrbuf;
	}
	iob_addbuf(&r->iob,r->hdrbuf,r->hlen);
}

// bestimmten http parameter auslesen und adresse zurueckgeben

const char* http_header(struct http_data* r,const char* h)
{
	long i;

	long l = array_bytes(&r->r);
	long sl = strlen(h);
	const char* c = array_start(&r->r);

	for (i=0; i+sl+2<l; ++i)
	{
		if (c[i]=='\n' && case_equalb(c+i+1,sl,h) && c[i+sl+1]==':')
		{
			c+=i+sl+1;
			if (*c==' ' || *c=='\t') ++c;
			return c;
		}
			return 0;
	}
}

void httpresponse(struct http_data* h,int64 s)
{
	char* c;
	array_cat0(&h->r);

	c = array_start(&h->r);

	if (byte_diff(c,4,"GET "))
	{
e400:
		httperror(h,"400 Invalid Request","This server only understands GET.");
	}
	else
	{
		char *d;
		int64 fd;
		struct stat s;
		
		// expect 'GET /uri?nnbjhg HTTP/1.*'
		c+=4;

		for (d=c; *d!=' '&&*d!='\t'&&*d!='\n'&&*d!='\r'; ++d) ;

		if (*d!=' ') goto e400;
		*d=0;
		if (c[0]!='/') goto e404;
		while (c[1]=='/') ++c;
		
		if (!byte_diff(c,9,"announce?"))
		{
			// info_hash, left, port, numwant, compact			
			struct ot_peer peer;
            ot_hash hash;
			byte_copy( peer.ip, h->ip, 4);
			peer.port = 6881;
			
			c+=9;
			while( *c!=' ' ) {
				if(!byte_diff(c,10,"info_hash="))
				{
                    size_t destlen = 20;
					// String is expected to be URL encoded, so expect
					// (%[0-9A-F][0-9A-F]){20}
                    
                    int s = scan_urlencoded( c+10, hash, &destlen);
                    if( c[s+10] != '&' )
                        goto e_parse;
                    
				}
				else if(!byte_diff(c,8,"numwant="))
				{
					
				}
				else if(!byte_diff(c,8,"compact="))
				{
					
				}
				else if(!byte_diff(c,5,"port="))
				{
					
				}
				else if(!byte_diff(c,5,"left="))
				{
					
				}

				while( *++c!=' ' && *c!='&');
			}
		}
		else if (!byte_diff(c,7,"scrape?"))
		{

		}
		else
		{
			httperror(h,"404 Not Found","No such file or directory.");
            goto e404;
		}

		c=h->hdrbuf=(char*)malloc(500);
		c+=fmt_str(c,"HTTP/1.1 Coming Up\r\nContent-Type: text/plain");
		c+=fmt_str(c,"\r\nContent-Length: ");
		/* ANSWER SIZE*/
		c+=fmt_ulonglong(c,s.st_size);
		c+=fmt_str(c,"\r\nLast-Modified: ");
		/* MODIFY DATE */
		c+=fmt_httpdate(c,s.st_mtime);
		c+=fmt_str(c,"\r\nConnection: close\r\n\r\n");
		iob_addbuf(&h->iob,h->hdrbuf,c - h->hdrbuf);
		iob_addbuf(&h->iob,tracker_answer, tzracker_answer_size);
	}
e404:
	io_dontwantread(s);
	io_wantwrite(s);
}

int main()
{
	int s=socket_tcp6();
	uint32 scope_id;
	char ip[16];
	uint16 port;

	if (socket_bind6_reuse(s,V6any,8000,0)==-1)
		panic("socket_bind6_reuse");

	if (socket_listen(s,16)==-1)
		panic("socket_listen");

	if (!io_fd(s))
		panic("io_fd");

	io_wantread(s);

	for (;;)
	{
		int64 i;
		io_wait();

		while ((i=io_canread())!=-1)
		{
			if (i==s)	// ist es der serversocket?
			{
				int n;
				while ((n=socket_accept6(s,ip,&port,&scope_id))!=-1)
				{
					if (io_fd(n))
					{
						struct http_data* h=(struct http_data*)malloc(sizeof(struct http_data));
						io_wantread(n);

						if (h)
						{
							byte_zero(h,sizeof(struct http_data));
							byte_copy(h->ip,ip,sizeof(ip));
							io_setcookie(n,h);
						} else
							io_close(n);
					} else
						io_close(n);
					buffer_putnlflush(buffer_2);
				}
				if (errno==EAGAIN)
					io_eagain(s);
				else
					carp("socket_accept6");
			}
			else
			{
				char buf[8192];
				struct http_data* h=io_getcookie(i);

				int l=io_tryread(i,buf,sizeof buf);
				if (l<=0)
				{
					if (h)
					{
						array_reset(&h->r);
						iob_reset(&h->iob);
						free(h->hdrbuf); h->hdrbuf=0;
					}
					io_close(i);
				}
				else
				{
					array_catb(&h->r,buf,l);

					if (array_failed(&h->r))
					{
						httperror(h,"500 Server Error","request too long.");
emerge:
						io_dontwantread(i);
						io_wantwrite(i);
					}
					else if (array_bytes(&h->r)>8192)
					{
						httperror(h,"500 request too long","You sent too much headers");
						goto emerge;
					}
					else if ((l=header_complete(h)))
					{
						httpresponse(h,i);
					}
				}
			}
		}

		while ((i=io_canwrite())!=-1)
		{
			struct http_data* h=io_getcookie(i);

			int64 r=iob_send(i,&h->iob);

			if (r==-1)
				io_eagain(i);
			else
				if (r<=0)
				{
					array_trunc(&h->r);
					iob_reset(&h->iob);
					free(h->hdrbuf); h->hdrbuf=0;
					io_close(i);
				}
		}
	}
	return 0;
}