dhcpd: apparently, sometimes IP is in ciaddr, not requested_ip...
also revert the part which appempted to "fix" that in client function old new delta udhcpd_main 1949 1964 +15 send_renew 142 105 -37 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 1/1 up/down: 15/-37) Total: -22 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
c7dc79e71d
commit
53f72bb3f0
@ -156,20 +156,7 @@ int FAST_FUNC send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
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init_packet(&packet, DHCPREQUEST);
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packet.xid = xid;
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/* RFC 2131:
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* "3.2 Client-server interaction - reusing a previously
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* allocated network address"...
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* The client broadcasts a DHCPREQUEST message on its local subnet.
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* The message includes the client's network address in the
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* REQUESTED_IP option. As the client has not received its
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* network address, it MUST NOT fill in the 'ciaddr' field."
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*
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* FIXME: we seem to not follow this, we do set ciaddr.
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*/
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packet.ciaddr = ciaddr;
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add_simple_option(packet.options, DHCP_REQUESTED_IP, ciaddr);
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if (server)
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add_simple_option(packet.options, DHCP_SERVER_ID, server);
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add_param_req_option(&packet);
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bb_info_msg("Sending renew...");
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@ -48,7 +48,7 @@ static void send_packet_to_client(struct dhcp_packet *dhcp_pkt, int force_broadc
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if (force_broadcast
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|| (dhcp_pkt->flags & htons(BROADCAST_FLAG))
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|| !dhcp_pkt->ciaddr
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|| dhcp_pkt->ciaddr == 0
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) {
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log1("Broadcasting packet to client");
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ciaddr = INADDR_BROADCAST;
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@ -466,16 +466,101 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
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case DHCPREQUEST:
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log1("Received REQUEST");
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/* RFC 2131:
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/* RFC 2131: "The REQUESTED_IP option MUST be set
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* to the value of 'yiaddr' in the DHCPOFFER message
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* from the server." */
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o DHCPREQUEST generated during SELECTING state:
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Client inserts the address of the selected server in 'server
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identifier', 'ciaddr' MUST be zero, 'requested IP address' MUST be
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filled in with the yiaddr value from the chosen DHCPOFFER.
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Note that the client may choose to collect several DHCPOFFER
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messages and select the "best" offer. The client indicates its
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selection by identifying the offering server in the DHCPREQUEST
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message. If the client receives no acceptable offers, the client
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may choose to try another DHCPDISCOVER message. Therefore, the
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servers may not receive a specific DHCPREQUEST from which they can
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decide whether or not the client has accepted the offer.
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o DHCPREQUEST generated during INIT-REBOOT state:
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'server identifier' MUST NOT be filled in, 'requested IP address'
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option MUST be filled in with client's notion of its previously
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assigned address. 'ciaddr' MUST be zero. The client is seeking to
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verify a previously allocated, cached configuration. Server SHOULD
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send a DHCPNAK message to the client if the 'requested IP address'
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is incorrect, or is on the wrong network.
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Determining whether a client in the INIT-REBOOT state is on the
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correct network is done by examining the contents of 'giaddr', the
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'requested IP address' option, and a database lookup. If the DHCP
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server detects that the client is on the wrong net (i.e., the
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result of applying the local subnet mask or remote subnet mask (if
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'giaddr' is not zero) to 'requested IP address' option value
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doesn't match reality), then the server SHOULD send a DHCPNAK
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message to the client.
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If the network is correct, then the DHCP server should check if
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the client's notion of its IP address is correct. If not, then the
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server SHOULD send a DHCPNAK message to the client. If the DHCP
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server has no record of this client, then it MUST remain silent,
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and MAY output a warning to the network administrator. This
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behavior is necessary for peaceful coexistence of non-
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communicating DHCP servers on the same wire.
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If 'giaddr' is 0x0 in the DHCPREQUEST message, the client is on
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the same subnet as the server. The server MUST broadcast the
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DHCPNAK message to the 0xffffffff broadcast address because the
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client may not have a correct network address or subnet mask, and
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the client may not be answering ARP requests.
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If 'giaddr' is set in the DHCPREQUEST message, the client is on a
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different subnet. The server MUST set the broadcast bit in the
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DHCPNAK, so that the relay agent will broadcast the DHCPNAK to the
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client, because the client may not have a correct network address
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or subnet mask, and the client may not be answering ARP requests.
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o DHCPREQUEST generated during RENEWING state:
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'server identifier' MUST NOT be filled in, 'requested IP address'
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option MUST NOT be filled in, 'ciaddr' MUST be filled in with
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client's IP address. In this situation, the client is completely
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configured, and is trying to extend its lease. This message will
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be unicast, so no relay agents will be involved in its
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transmission. Because 'giaddr' is therefore not filled in, the
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DHCP server will trust the value in 'ciaddr', and use it when
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replying to the client.
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A client MAY choose to renew or extend its lease prior to T1. The
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server may choose not to extend the lease (as a policy decision by
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the network administrator), but should return a DHCPACK message
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regardless.
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o DHCPREQUEST generated during REBINDING state:
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'server identifier' MUST NOT be filled in, 'requested IP address'
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option MUST NOT be filled in, 'ciaddr' MUST be filled in with
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client's IP address. In this situation, the client is completely
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configured, and is trying to extend its lease. This message MUST
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be broadcast to the 0xffffffff IP broadcast address. The DHCP
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server SHOULD check 'ciaddr' for correctness before replying to
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the DHCPREQUEST.
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The DHCPREQUEST from a REBINDING client is intended to accommodate
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sites that have multiple DHCP servers and a mechanism for
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maintaining consistency among leases managed by multiple servers.
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A DHCP server MAY extend a client's lease only if it has local
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administrative authority to do so.
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*/
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if (!requested_opt) {
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log1("no requested IP, ignoring");
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requested_nip = packet.ciaddr;
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if (requested_nip == 0) {
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log1("no requested IP and no ciaddr, ignoring");
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break;
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}
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}
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if (lease && requested_nip == lease->lease_nip) {
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/* client requests IP which matches the lease.
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/* client requested or configured IP matches the lease.
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* ACK it, and bump lease expiration time. */
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send_ACK(&packet, lease->lease_nip);
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break;
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