Ejemplo n.º 1
0
/* NOINLINE: limit stack usage in caller */
static NOINLINE void send_ACK(struct dhcp_packet *oldpacket, uint32_t yiaddr)
{
	struct dhcp_packet packet;
	uint32_t lease_time_sec;
	struct in_addr addr;
	const char *p_host_name;

	init_packet(&packet, oldpacket, DHCPACK);
	packet.yiaddr = yiaddr;

	lease_time_sec = select_lease_time(oldpacket);
	udhcp_add_simple_option(&packet, DHCP_LEASE_TIME, htonl(lease_time_sec));

	add_server_options(&packet);

	addr.s_addr = yiaddr;
	bb_info_msg("Sending ACK to %s", inet_ntoa(addr));
	send_packet(&packet, /*force_bcast:*/ 0);

	p_host_name = (const char*) udhcp_get_option(oldpacket, DHCP_HOST_NAME);
	add_lease(packet.chaddr, packet.yiaddr,
		lease_time_sec,
		p_host_name,
		p_host_name ? (unsigned char)p_host_name[OPT_LEN - OPT_DATA] : 0
	);
	if (ENABLE_FEATURE_UDHCPD_WRITE_LEASES_EARLY) {
		/* rewrite the file with leases at every new acceptance */
		write_leases();
	}
}
Ejemplo n.º 2
0
static void init_packet(struct dhcp_packet *packet, struct dhcp_packet *oldpacket, char type)
{
	/* Sets op, htype, hlen, cookie fields
	 * and adds DHCP_MESSAGE_TYPE option */
	udhcp_init_header(packet, type);

	packet->xid = oldpacket->xid;
	memcpy(packet->chaddr, oldpacket->chaddr, sizeof(oldpacket->chaddr));
	packet->flags = oldpacket->flags;
	packet->gateway_nip = oldpacket->gateway_nip;
	packet->ciaddr = oldpacket->ciaddr;
	udhcp_add_simple_option(packet, DHCP_SERVER_ID, server_config.server_nip);
}
Ejemplo n.º 3
0
void FAST_FUNC udhcp_init_header(struct dhcp_packet *packet, char type)
{
	memset(packet, 0, sizeof(*packet));
	packet->op = BOOTREQUEST; /* if client to a server */
	switch (type) {
	case DHCPOFFER:
	case DHCPACK:
	case DHCPNAK:
		packet->op = BOOTREPLY; /* if server to client */
	}
	packet->htype = 1; /* ethernet */
	packet->hlen = 6;
	packet->cookie = htonl(DHCP_MAGIC);
	if (DHCP_END != 0)
		packet->options[0] = DHCP_END;
	udhcp_add_simple_option(packet, DHCP_MESSAGE_TYPE, type);
}
Ejemplo n.º 4
0
/* NOINLINE: limit stack usage in caller */
static NOINLINE void send_offer(struct dhcp_packet *oldpacket,
		uint32_t static_lease_nip,
		struct dyn_lease *lease,
		uint8_t *requested_ip_opt,
		unsigned arpping_ms)
{
	struct dhcp_packet packet;
	uint32_t lease_time_sec;
	struct in_addr addr;

	init_packet(&packet, oldpacket, DHCPOFFER);

	/* If it is a static lease, use its IP */
	packet.yiaddr = static_lease_nip;
	/* Else: */
	if (!static_lease_nip) {
		/* We have no static lease for client's chaddr */
		uint32_t req_nip;
		const char *p_host_name;

		if (lease) {
			/* We have a dynamic lease for client's chaddr.
			 * Reuse its IP (even if lease is expired).
			 * Note that we ignore requested IP in this case.
			 */
			packet.yiaddr = lease->lease_nip;
		}
		/* Or: if client has requested an IP */
		else if (requested_ip_opt != NULL
		 /* (read IP) */
		 && (move_from_unaligned32(req_nip, requested_ip_opt), 1)
		 /* and the IP is in the lease range */
		 && ntohl(req_nip) >= server_config.start_ip
		 && ntohl(req_nip) <= server_config.end_ip
		 /* and */
		 && (  !(lease = find_lease_by_nip(req_nip)) /* is not already taken */
		    || is_expired_lease(lease) /* or is taken, but expired */
		    )
		) {
			packet.yiaddr = req_nip;
		}
		else {
			/* Otherwise, find a free IP */
			packet.yiaddr = find_free_or_expired_nip(oldpacket->chaddr, arpping_ms);
		}

		if (!packet.yiaddr) {
			bb_error_msg("no free IP addresses. OFFER abandoned");
			return;
		}
		/* Reserve the IP for a short time hoping to get DHCPREQUEST soon */
		p_host_name = (const char*) udhcp_get_option(oldpacket, DHCP_HOST_NAME);
		lease = add_lease(packet.chaddr, packet.yiaddr,
				server_config.offer_time,
				p_host_name,
				p_host_name ? (unsigned char)p_host_name[OPT_LEN - OPT_DATA] : 0
		);
		if (!lease) {
			bb_error_msg("no free IP addresses. OFFER abandoned");
			return;
		}
	}

	lease_time_sec = select_lease_time(oldpacket);
	udhcp_add_simple_option(&packet, DHCP_LEASE_TIME, htonl(lease_time_sec));
	add_server_options(&packet);

	addr.s_addr = packet.yiaddr;
	bb_info_msg("Sending OFFER of %s", inet_ntoa(addr));
	/* send_packet emits error message itself if it detects failure */
	send_packet(&packet, /*force_bcast:*/ 0);
}