Esempio n. 1
0
int
masq_ftp_out (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, __u32 maddr)
{
        struct sk_buff *skb;
	struct iphdr *iph;
	struct tcphdr *th;
	char *p, *data, *data_limit;
	unsigned char p1,p2,p3,p4,p5,p6;
	__u32 from;
	__u16 port;
	struct ip_masq *n_ms;
	char buf[24];		/* xxx.xxx.xxx.xxx,ppp,ppp\000 */
        unsigned buf_len;
	int diff;

        skb = *skb_p;
	iph = skb->nh.iph;
        th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
        data = (char *)&th[1];

        data_limit = skb->h.raw + skb->len - 18;
        if (skb->len >= 6 && (memcmp(data, "PASV\r\n", 6) == 0 || memcmp(data, "pasv\r\n", 6) == 0))
		ms->app_data = &masq_ftp_pasv;

	while (data < data_limit)
	{
		if (memcmp(data,"PORT ",5) && memcmp(data,"port ",5))
		{
			data ++;
			continue;
		}
		p = data+5;
 		p1 = simple_strtoul(data+5,&data,10);
		if (*data!=',')
			continue;
		p2 = simple_strtoul(data+1,&data,10);
		if (*data!=',')
			continue;
		p3 = simple_strtoul(data+1,&data,10);
		if (*data!=',')
			continue;
		p4 = simple_strtoul(data+1,&data,10);
		if (*data!=',')
			continue;
		p5 = simple_strtoul(data+1,&data,10);
		if (*data!=',')
			continue;
		p6 = simple_strtoul(data+1,&data,10);
		if (*data!='\r' && *data!='\n')
			continue;

		from = (p1<<24) | (p2<<16) | (p3<<8) | p4;
		port = (p5<<8) | p6;

		IP_MASQ_DEBUG(1-debug, "PORT %X:%X detected\n",from,port);

		/*
		 * Now update or create an masquerade entry for it
		 */

		IP_MASQ_DEBUG(1-debug, "protocol %d %lX:%X %X:%X\n", iph->protocol, htonl(from), htons(port), iph->daddr, 0);

		n_ms = ip_masq_out_get(iph->protocol,
					 htonl(from), htons(port),
					 iph->daddr, 0);
		if (!n_ms) {
			n_ms = ip_masq_new(IPPROTO_TCP,
					   maddr, 0,
					   htonl(from), htons(port),
					   iph->daddr, 0,
					   IP_MASQ_F_NO_DPORT);

			if (n_ms==NULL)
				return 0;
			ip_masq_control_add(n_ms, ms);
		}

		/*
		 * Replace the old PORT with the new one
		 */
		from = ntohl(n_ms->maddr);
		port = ntohs(n_ms->mport);
		sprintf(buf,"%d,%d,%d,%d,%d,%d",
			from>>24&255,from>>16&255,from>>8&255,from&255,
			port>>8&255,port&255);
		buf_len = strlen(buf);

		IP_MASQ_DEBUG(1-debug, "new PORT %X:%X\n",from,port);

		/*
		 * Calculate required delta-offset to keep TCP happy
		 */
		
		diff = buf_len - (data-p);
		
		/*
		 *	No shift.
		 */
		
		if (diff==0) {
			/*
			 * simple case, just replace the old PORT cmd
 			 */
 			memcpy(p,buf,buf_len);
 		} else {

			*skb_p = ip_masq_skb_replace(skb, GFP_ATOMIC, p, data-p, buf, buf_len);
		}
                /*
                 * 	Move tunnel to listen state
                 */
		ip_masq_listen(n_ms);
		ip_masq_put(n_ms);

                return diff;

	}
	return 0;

}
Esempio n. 2
0
int
masq_ftp_in (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, __u32 maddr)
{
	struct sk_buff *skb;
	struct iphdr *iph;
	struct tcphdr *th;
	char *data, *data_limit;
	unsigned char p1,p2,p3,p4,p5,p6;
	__u32 to;
	__u16 port;
	struct ip_masq *n_ms;

	if (ms->app_data != &masq_ftp_pasv)
		return 0;	/* quick exit if no outstanding PASV */

	skb = *skb_p;
	iph = skb->nh.iph;
	th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
	data = (char *)&th[1];
	data_limit = skb->h.raw + skb->len;

	while (data < data_limit && *data != ' ')
		++data;	
	while (data < data_limit && *data == ' ')
		++data;	
	data += 22;
	if (data >= data_limit || *data != '(')
		return 0;
	p1 = simple_strtoul(data+1, &data, 10);
	if (data >= data_limit || *data != ',')
		return 0;
	p2 = simple_strtoul(data+1, &data, 10);
	if (data >= data_limit || *data != ',')
		return 0;
	p3 = simple_strtoul(data+1, &data, 10);
	if (data >= data_limit || *data != ',')
		return 0;
	p4 = simple_strtoul(data+1, &data, 10);
	if (data >= data_limit || *data != ',')
		return 0;
	p5 = simple_strtoul(data+1, &data, 10);
	if (data >= data_limit || *data != ',')
		return 0;
	p6 = simple_strtoul(data+1, &data, 10);
	if (data >= data_limit || *data != ')')
		return 0;

	to = (p1<<24) | (p2<<16) | (p3<<8) | p4;
	port = (p5<<8) | p6;

	/*
	 * Now update or create an masquerade entry for it
	 */
	IP_MASQ_DEBUG(1-debug, "PASV response %lX:%X %X:%X detected\n", ntohl(ms->saddr), 0, to, port);

	n_ms = ip_masq_out_get(iph->protocol,
				 ms->saddr, 0,
				 htonl(to), htons(port));
	if (!n_ms) {
		n_ms = ip_masq_new(IPPROTO_TCP,
					maddr, 0,
					ms->saddr, 0,
					htonl(to), htons(port),
					IP_MASQ_F_NO_SPORT);

		if (n_ms==NULL)
			return 0;
		ip_masq_control_add(n_ms, ms);
	}

#if 0	/* v0.12 state processing */

	/*
	 * keep for a bit longer than tcp_fin, client may not issue open
	 * to server port before tcp_fin_timeout.
	 */
	n_ms->timeout = ip_masq_expire->tcp_fin_timeout*3;
#endif
	ms->app_data = NULL;
	ip_masq_put(n_ms);

	return 0;	/* no diff required for incoming packets, thank goodness */
}