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udhcpd: don't fail ARP check if returned MAC matches client's one

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Also, do not unicast replies to yiaddr.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2009-06-16 10:20:27 +02:00
parent 1f363a0867
commit 47f2d7ef7d
6 changed files with 67 additions and 34 deletions
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53
networking/udhcp/serverpacket.c
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@ -31,7 +31,8 @@ static int send_packet_to_relay(struct dhcpMessage *payload)
{
DEBUG("Forwarding packet to relay");
return udhcp_send_kernel_packet(payload, server_config.server, SERVER_PORT,
return udhcp_send_kernel_packet(payload,
server_config.server, SERVER_PORT,
payload->giaddr, SERVER_PORT);
}
@ -42,23 +43,31 @@ static int send_packet_to_client(struct dhcpMessage *payload, int force_broadcas
const uint8_t *chaddr;
uint32_t ciaddr;
if (force_broadcast) {
DEBUG("broadcasting packet to client (NAK)");
ciaddr = INADDR_BROADCAST;
chaddr = MAC_BCAST_ADDR;
} else if (payload->ciaddr) {
DEBUG("unicasting packet to client ciaddr");
ciaddr = payload->ciaddr;
chaddr = payload->chaddr;
} else if (payload->flags & htons(BROADCAST_FLAG)) {
DEBUG("broadcasting packet to client (requested)");
// Was:
//if (force_broadcast) { /* broadcast */ }
//else if (payload->ciaddr) { /* unicast to payload->ciaddr */ }
//else if (payload->flags & htons(BROADCAST_FLAG)) { /* broadcast */ }
//else { /* unicast to payload->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 payload->yiaddr!
// payload->ciaddr, OTOH, comes from client's request packet,
// and can be used.
if (force_broadcast
|| (payload->flags & htons(BROADCAST_FLAG))
|| !payload->ciaddr
) {
DEBUG("broadcasting packet to client");
ciaddr = INADDR_BROADCAST;
chaddr = MAC_BCAST_ADDR;
} else {
DEBUG("unicasting packet to client yiaddr");
ciaddr = payload->yiaddr;
DEBUG("unicasting packet to client ciaddr");
ciaddr = payload->ciaddr;
chaddr = payload->chaddr;
}
return udhcp_send_raw_packet(payload,
/*src*/ server_config.server, SERVER_PORT,
/*dst*/ ciaddr, CLIENT_PORT, chaddr,
@ -118,17 +127,18 @@ int FAST_FUNC send_offer(struct dhcpMessage *oldpacket)
struct dhcpOfferedAddr *lease;
lease = find_lease_by_chaddr(oldpacket->chaddr);
/* the client is in our lease/offered table */
/* The client is in our lease/offered table */
if (lease) {
signed_leasetime_t tmp = lease->expires - time(NULL);
if (tmp >= 0)
lease_time_aligned = tmp;
packet.yiaddr = lease->yiaddr;
/* Or the client has requested an ip */
} else if ((req = get_option(oldpacket, DHCP_REQUESTED_IP)) != NULL
/* Don't look here (ugly hackish thing to do) */
}
/* Or the client has requested an IP */
else if ((req = get_option(oldpacket, DHCP_REQUESTED_IP)) != NULL
/* (read IP) */
&& (move_from_unaligned32(req_align, req), 1)
/* and the ip is in the lease range */
/* and the IP is in the lease range */
&& ntohl(req_align) >= server_config.start_ip
&& ntohl(req_align) <= server_config.end_ip
/* and is not already taken/offered */
@ -137,9 +147,10 @@ int FAST_FUNC send_offer(struct dhcpMessage *oldpacket)
|| lease_expired(lease))
) {
packet.yiaddr = req_align;
/* otherwise, find a free IP */
} else {
packet.yiaddr = find_free_or_expired_address();
}
/* Otherwise, find a free IP */
else {
packet.yiaddr = find_free_or_expired_address(oldpacket->chaddr);
}
if (!packet.yiaddr) {