udhcp: move serverpacket.c into dhcpd.c, no other changes

function                                             old     new   delta
udhcpd_main                                         1480    1956    +476
send_inform                                           83       -     -83
send_offer                                           376       -    -376
------------------------------------------------------------------------------
(add/remove: 0/3 grow/shrink: 1/0 up/down: 476/-459)           Total: 17 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 262 insertions, 3 deletions

diff --git a/networking/udhcp/dhcpd.c b/networking/udhcp/dhcpd.c
index dc5d9ffe9..26fb3045f 100644
--- a/networking/udhcp/dhcpd.c
+++ b/networking/udhcp/dhcpd.c
@@ -1,13 +1,24 @@
 /* vi: set sw=4 ts=4: */
-/* dhcpd.c
- *
+/*
  * udhcp Server
  * Copyright (C) 1999 Matthew Ramsay <matthewr@moreton.com.au>
  *			Chris Trew <ctrew@moreton.com.au>
  *
  * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
 #include <syslog.h>
@@ -17,6 +28,254 @@
 #include "options.h"
 
 
+/* send a packet to gateway_nip using the kernel ip stack */
+static int send_packet_to_relay(struct dhcp_packet *dhcp_pkt)
+{
+	log1("Forwarding packet to relay");
+
+	return udhcp_send_kernel_packet(dhcp_pkt,
+			server_config.server_nip, SERVER_PORT,
+			dhcp_pkt->gateway_nip, SERVER_PORT);
+}
+
+/* send a packet to a specific mac address and ip address by creating our own ip packet */
+static int send_packet_to_client(struct dhcp_packet *dhcp_pkt, int force_broadcast)
+{
+	const uint8_t *chaddr;
+	uint32_t ciaddr;
+
+	// Was:
+	//if (force_broadcast) { /* broadcast */ }
+	//else if (dhcp_pkt->ciaddr) { /* unicast to dhcp_pkt->ciaddr */ }
+	//else if (dhcp_pkt->flags & htons(BROADCAST_FLAG)) { /* broadcast */ }
+	//else { /* unicast to dhcp_pkt->yiaddr */ }
+	// But this is wrong: yiaddr is _our_ idea what client's IP is
+	// (for example, from lease file). Client may not know that,
+	// and may not have UDP socket listening on that IP!
+	// We should never unicast to dhcp_pkt->yiaddr!
+	// dhcp_pkt->ciaddr, OTOH, comes from client's request packet,
+	// and can be used.
+
+	if (force_broadcast
+	 || (dhcp_pkt->flags & htons(BROADCAST_FLAG))
+	 || !dhcp_pkt->ciaddr
+	) {
+		log1("Broadcasting packet to client");
+		ciaddr = INADDR_BROADCAST;
+		chaddr = MAC_BCAST_ADDR;
+	} else {
+		log1("Unicasting packet to client ciaddr");
+		ciaddr = dhcp_pkt->ciaddr;
+		chaddr = dhcp_pkt->chaddr;
+	}
+
+	return udhcp_send_raw_packet(dhcp_pkt,
+		/*src*/ server_config.server_nip, SERVER_PORT,
+		/*dst*/ ciaddr, CLIENT_PORT, chaddr,
+		server_config.ifindex);
+}
+
+/* send a dhcp packet, if force broadcast is set, the packet will be broadcast to the client */
+static int send_packet(struct dhcp_packet *dhcp_pkt, int force_broadcast)
+{
+	if (dhcp_pkt->gateway_nip)
+		return send_packet_to_relay(dhcp_pkt);
+	return send_packet_to_client(dhcp_pkt, force_broadcast);
+}
+
+static void init_packet(struct dhcp_packet *packet, struct dhcp_packet *oldpacket, char type)
+{
+	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;
+	add_simple_option(packet->options, DHCP_SERVER_ID, server_config.server_nip);
+}
+
+/* add in the bootp options */
+static void add_bootp_options(struct dhcp_packet *packet)
+{
+	packet->siaddr_nip = server_config.siaddr_nip;
+	if (server_config.sname)
+		strncpy((char*)packet->sname, server_config.sname, sizeof(packet->sname) - 1);
+	if (server_config.boot_file)
+		strncpy((char*)packet->file, server_config.boot_file, sizeof(packet->file) - 1);
+}
+
+static uint32_t select_lease_time(struct dhcp_packet *packet)
+{
+	uint32_t lease_time_sec = server_config.max_lease_sec;
+	uint8_t *lease_time_opt = get_option(packet, DHCP_LEASE_TIME);
+	if (lease_time_opt) {
+		move_from_unaligned32(lease_time_sec, lease_time_opt);
+		lease_time_sec = ntohl(lease_time_sec);
+		if (lease_time_sec > server_config.max_lease_sec)
+			lease_time_sec = server_config.max_lease_sec;
+		if (lease_time_sec < server_config.min_lease_sec)
+			lease_time_sec = server_config.min_lease_sec;
+	}
+	return lease_time_sec;
+}
+
+/* send a DHCP OFFER to a DHCP DISCOVER */
+static int send_offer(struct dhcp_packet *oldpacket)
+{
+	struct dhcp_packet packet;
+	uint32_t req_nip;
+	uint32_t lease_time_sec = server_config.max_lease_sec;
+	uint32_t static_lease_ip;
+	uint8_t *req_ip_opt;
+	const char *p_host_name;
+	struct option_set *curr;
+	struct in_addr addr;
+
+	init_packet(&packet, oldpacket, DHCPOFFER);
+
+	static_lease_ip = get_static_nip_by_mac(server_config.static_leases, oldpacket->chaddr);
+
+	/* ADDME: if static, short circuit */
+	if (!static_lease_ip) {
+		struct dyn_lease *lease;
+
+		lease = find_lease_by_mac(oldpacket->chaddr);
+		/* The client is in our lease/offered table */
+		if (lease) {
+			signed_leasetime_t tmp = lease->expires - time(NULL);
+			if (tmp >= 0)
+				lease_time_sec = tmp;
+			packet.yiaddr = lease->lease_nip;
+		}
+		/* Or the client has requested an IP */
+		else if ((req_ip_opt = get_option(oldpacket, DHCP_REQUESTED_IP)) != NULL
+		 /* (read IP) */
+		 && (move_from_unaligned32(req_nip, req_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 is not already taken/offered */
+		 && (!(lease = find_lease_by_nip(req_nip))
+			/* or its taken, but expired */
+			|| is_expired_lease(lease))
+		) {
+			packet.yiaddr = req_nip;
+		}
+		/* Otherwise, find a free IP */
+		else {
+			packet.yiaddr = find_free_or_expired_nip(oldpacket->chaddr);
+		}
+
+		if (!packet.yiaddr) {
+			bb_error_msg("no IP addresses to give - OFFER abandoned");
+			return -1;
+		}
+		p_host_name = (const char*) get_option(oldpacket, DHCP_HOST_NAME);
+		if (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
+			) == 0
+		) {
+			bb_error_msg("lease pool is full - OFFER abandoned");
+			return -1;
+		}
+		lease_time_sec = select_lease_time(oldpacket);
+	} else {
+		/* It is a static lease... use it */
+		packet.yiaddr = static_lease_ip;
+	}
+
+	add_simple_option(packet.options, DHCP_LEASE_TIME, htonl(lease_time_sec));
+
+	curr = server_config.options;
+	while (curr) {
+		if (curr->data[OPT_CODE] != DHCP_LEASE_TIME)
+			add_option_string(packet.options, curr->data);
+		curr = curr->next;
+	}
+
+	add_bootp_options(&packet);
+
+	addr.s_addr = packet.yiaddr;
+	bb_info_msg("Sending OFFER of %s", inet_ntoa(addr));
+	return send_packet(&packet, 0);
+}
+
+static int send_NAK(struct dhcp_packet *oldpacket)
+{
+	struct dhcp_packet packet;
+
+	init_packet(&packet, oldpacket, DHCPNAK);
+
+	log1("Sending NAK");
+	return send_packet(&packet, 1);
+}
+
+static int send_ACK(struct dhcp_packet *oldpacket, uint32_t yiaddr)
+{
+	struct dhcp_packet packet;
+	struct option_set *curr;
+	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);
+
+	add_simple_option(packet.options, DHCP_LEASE_TIME, htonl(lease_time_sec));
+
+	curr = server_config.options;
+	while (curr) {
+		if (curr->data[OPT_CODE] != DHCP_LEASE_TIME)
+			add_option_string(packet.options, curr->data);
+		curr = curr->next;
+	}
+
+	add_bootp_options(&packet);
+
+	addr.s_addr = packet.yiaddr;
+	bb_info_msg("Sending ACK to %s", inet_ntoa(addr));
+
+	if (send_packet(&packet, 0) < 0)
+		return -1;
+
+	p_host_name = (const char*) 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();
+	}
+
+	return 0;
+}
+
+static int send_inform(struct dhcp_packet *oldpacket)
+{
+	struct dhcp_packet packet;
+	struct option_set *curr;
+
+	init_packet(&packet, oldpacket, DHCPACK);
+
+	curr = server_config.options;
+	while (curr) {
+		if (curr->data[OPT_CODE] != DHCP_LEASE_TIME)
+			add_option_string(packet.options, curr->data);
+		curr = curr->next;
+	}
+
+	add_bootp_options(&packet);
+
+	return send_packet(&packet, 0);
+}
+
+
 /* globals */
 struct dyn_lease *g_leases;
 /* struct server_config_t server_config is in bb_common_bufsiz1 */