433 lines
13 KiB
C++
433 lines
13 KiB
C++
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// DHCP look-up functions based on the udp client
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// http://www.ietf.org/rfc/rfc2131.txt
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//
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// Author: Andrew Lindsay
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// Rewritten and optimized by Jean-Claude Wippler, http://jeelabs.org/
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//
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// Rewritten dhcpStateMachine by Chris van den Hooven
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// as to implement dhcp-renew when lease expires (jun 2012)
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//
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// Various modifications and bug fixes contributed by Victor Aprea (oct 2012)
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//
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// Copyright: GPL V2
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// See http://www.gnu.org/licenses/gpl.html
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//#define DHCPDEBUG
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#include "EtherCard.h"
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#include "net.h"
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#define gPB ether.buffer
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#define DHCP_BOOTREQUEST 1
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#define DHCP_BOOTRESPONSE 2
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// DHCP Message Type (option 53) (ref RFC 2132)
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#define DHCP_DISCOVER 1
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#define DHCP_OFFER 2
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#define DHCP_REQUEST 3
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#define DHCP_DECLINE 4
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#define DHCP_ACK 5
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#define DHCP_NAK 6
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#define DHCP_RELEASE 7
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// DHCP States for access in applications (ref RFC 2131)
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enum {
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DHCP_STATE_INIT,
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DHCP_STATE_SELECTING,
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DHCP_STATE_REQUESTING,
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DHCP_STATE_BOUND,
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DHCP_STATE_RENEWING,
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};
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/*
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op 1 Message op code / message type.
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1 = BOOTREQUEST, 2 = BOOTREPLY
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htype 1 Hardware address type, see ARP section in "Assigned
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Numbers" RFC; e.g., '1' = 10mb ethernet.
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hlen 1 Hardware address length (e.g. '6' for 10mb
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ethernet).
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hops 1 Client sets to zero, optionally used by relay agents
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when booting via a relay agent.
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xid 4 Transaction ID, a random number chosen by the
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client, used by the client and server to associate
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messages and responses between a client and a
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server.
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secs 2 Filled in by client, seconds elapsed since client
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began address acquisition or renewal process.
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flags 2 Flags (see figure 2).
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ciaddr 4 Client IP address; only filled in if client is in
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BOUND, RENEW or REBINDING state and can respond
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to ARP requests.
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yiaddr 4 'your' (client) IP address.
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siaddr 4 IP address of next server to use in bootstrap;
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returned in DHCPOFFER, DHCPACK by server.
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giaddr 4 Relay agent IP address, used in booting via a
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relay agent.
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chaddr 16 Client hardware address.
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sname 64 Optional server host name, null terminated string.
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file 128 Boot file name, null terminated string; "generic"
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name or null in DHCPDISCOVER, fully qualified
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directory-path name in DHCPOFFER.
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options var Optional parameters field. See the options
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documents for a list of defined options.
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*/
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// size 236
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typedef struct {
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byte op, htype, hlen, hops;
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uint32_t xid;
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uint16_t secs, flags;
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byte ciaddr[4], yiaddr[4], siaddr[4], giaddr[4];
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byte chaddr[16], sname[64], file[128];
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// options
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} DHCPdata;
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#define DHCP_SERVER_PORT 67
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#define DHCP_CLIENT_PORT 68
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// timeouts im ms
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#define DHCP_REQUEST_TIMEOUT 10000
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#define DHCP_HOSTNAME_MAX_LEN 32
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// RFC 2132 Section 3.3:
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// The time value of 0xffffffff is reserved to represent "infinity".
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#define DHCP_INFINITE_LEASE 0xffffffff
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static byte dhcpState = DHCP_STATE_INIT;
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static char hostname[DHCP_HOSTNAME_MAX_LEN] = "Arduino-00";
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static uint32_t currentXid;
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static uint32_t stateTimer;
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static uint32_t leaseStart;
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static uint32_t leaseTime;
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static byte* bufPtr;
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static uint8_t dhcpCustomOptionNum = 0;
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static DhcpOptionCallback dhcpCustomOptionCallback = NULL;
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// static uint8_t allOnes[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
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static void addToBuf (byte b) {
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*bufPtr++ = b;
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}
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static void addBytes (byte len, const byte* data) {
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while (len-- > 0)
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addToBuf(*data++);
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}
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// Main DHCP sending function
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// implemented
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// state / msgtype
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// INIT / DHCPDISCOVER
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// SELECTING / DHCPREQUEST
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// BOUND (RENEWING) / DHCPREQUEST
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// ----------------------------------------------------------
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// | |SELECTING |RENEWING |INIT |
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// ----------------------------------------------------------
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// |broad/unicast |broadcast |unicast |broadcast |
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// |server-ip |MUST |MUST NOT |MUST NOT | option 54
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// |requested-ip |MUST |MUST NOT |MUST NOT | option 50
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// |ciaddr |zero |IP address |zero |
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// ----------------------------------------------------------
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// options used (both send/receive)
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// 12 Host Name Option
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// 50 Requested IP Address
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// 51 IP Address Lease Time
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// 53 DHCP message type
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// 54 Server-identifier
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// 55 Parameter request list
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// 58 Renewal (T1) Time Value
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// 61 Client-identifier
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// 255 End
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static void send_dhcp_message(uint8_t *requestip) {
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uint8_t allOnes[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
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memset(gPB, 0, UDP_DATA_P + sizeof( DHCPdata ));
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EtherCard::udpPrepare(DHCP_CLIENT_PORT,
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(dhcpState == DHCP_STATE_BOUND ? EtherCard::dhcpip : allOnes),
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DHCP_SERVER_PORT);
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// If we ever don't do this, the DHCP renewal gets sent to whatever random
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// destmacaddr was used by other code. Rather than cache the MAC address of
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// the DHCP server, just force a broadcast here in all cases.
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EtherCard::copyMac(gPB + ETH_DST_MAC, allOnes); //force broadcast mac
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// Build DHCP Packet from buf[UDP_DATA_P]
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DHCPdata *dhcpPtr = (DHCPdata*) (gPB + UDP_DATA_P);
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dhcpPtr->op = DHCP_BOOTREQUEST;
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dhcpPtr->htype = 1;
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dhcpPtr->hlen = 6;
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dhcpPtr->xid = currentXid;
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if (dhcpState == DHCP_STATE_BOUND) {
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EtherCard::copyIp(dhcpPtr->ciaddr, EtherCard::myip);
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}
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EtherCard::copyMac(dhcpPtr->chaddr, EtherCard::mymac);
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// options defined as option, length, value
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bufPtr = gPB + UDP_DATA_P + sizeof( DHCPdata );
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// DHCP magic cookie, followed by message type
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static byte cookie[] = { 99, 130, 83, 99, 53, 1 };
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addBytes(sizeof cookie, cookie);
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// addToBuf(53); // DHCP_STATE_SELECTING, DHCP_STATE_REQUESTING
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// addToBuf(1); // Length
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addToBuf(dhcpState == DHCP_STATE_INIT ? DHCP_DISCOVER : DHCP_REQUEST);
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// Client Identifier Option, this is the client mac address
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addToBuf(61); // Client identifier
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addToBuf(7); // Length
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addToBuf(0x01); // Ethernet
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addBytes(6, EtherCard::mymac);
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addToBuf(12); // Host name Option
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addToBuf(10);
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addBytes(10, (byte*) hostname);
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if (requestip != NULL) {
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addToBuf(50); // Request IP address
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addToBuf(4);
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addBytes(4, requestip);
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addToBuf(54); // DHCP Server IP address
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addToBuf(4);
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addBytes(4, EtherCard::dhcpip);
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}
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// Additional info in parameter list - minimal list for what we need
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byte len = 3;
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if (dhcpCustomOptionNum)
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len++;
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addToBuf(55); // Parameter request list
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addToBuf(len); // Length
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addToBuf(1); // Subnet mask
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addToBuf(3); // Route/Gateway
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addToBuf(6); // DNS Server
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if (dhcpCustomOptionNum)
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addToBuf(dhcpCustomOptionNum); // Custom option
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addToBuf(255); // end option
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// packet size will be under 300 bytes
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EtherCard::udpTransmit((bufPtr - gPB) - UDP_DATA_P);
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}
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static void process_dhcp_offer(uint16_t len, uint8_t *offeredip) {
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// Map struct onto payload
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DHCPdata *dhcpPtr = (DHCPdata*) (gPB + UDP_DATA_P);
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// Offered IP address is in yiaddr
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EtherCard::copyIp(offeredip, dhcpPtr->yiaddr);
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// Search for the
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byte *ptr = (byte*) (dhcpPtr + 1) + 4;
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do {
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byte option = *ptr++;
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byte optionLen = *ptr++;
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if (option == 54) {
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EtherCard::copyIp(EtherCard::dhcpip, ptr);
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break;
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}
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ptr += optionLen;
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} while (ptr < gPB + len);
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}
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static void process_dhcp_ack(uint16_t len) {
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// Map struct onto payload
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DHCPdata *dhcpPtr = (DHCPdata*) (gPB + UDP_DATA_P);
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// Allocated IP address is in yiaddr
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EtherCard::copyIp(EtherCard::myip, dhcpPtr->yiaddr);
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// Scan through variable length option list identifying options we want
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byte *ptr = (byte*) (dhcpPtr + 1) + 4;
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bool done = false;
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do {
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byte option = *ptr++;
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byte optionLen = *ptr++;
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switch (option) {
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case 1:
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EtherCard::copyIp(EtherCard::netmask, ptr);
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break;
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case 3:
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EtherCard::copyIp(EtherCard::gwip, ptr);
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break;
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case 6:
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EtherCard::copyIp(EtherCard::dnsip, ptr);
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break;
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case 51:
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case 58:
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leaseTime = 0; // option 58 = Renewal Time, 51 = Lease Time
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for (byte i = 0; i<4; i++)
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leaseTime = (leaseTime << 8) + ptr[i];
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if (leaseTime != DHCP_INFINITE_LEASE) {
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leaseTime *= 1000; // milliseconds
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}
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break;
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case 255:
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done = true;
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break;
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default: {
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// Is is a custom configured option?
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if (dhcpCustomOptionCallback && option == dhcpCustomOptionNum) {
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dhcpCustomOptionCallback(option, ptr, optionLen);
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}
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}
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}
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ptr += optionLen;
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} while (!done && ptr < gPB + len);
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}
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static bool dhcp_received_message_type (uint16_t len, byte msgType) {
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// Map struct onto payload
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DHCPdata *dhcpPtr = (DHCPdata*) (gPB + UDP_DATA_P);
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if (len >= 70 && gPB[UDP_SRC_PORT_L_P] == DHCP_SERVER_PORT &&
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dhcpPtr->xid == currentXid ) {
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byte *ptr = (byte*) (dhcpPtr + 1) + 4;
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do {
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byte option = *ptr++;
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byte optionLen = *ptr++;
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if(option == 53 && *ptr == msgType ) {
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// DHCP Message type match found
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return true;
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}
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ptr += optionLen;
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} while (ptr < gPB + len);
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}
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return false;
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}
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static char toAsciiHex(byte b) {
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char c = b & 0x0f;
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c += (c <= 9) ? '0' : 'A'-10;
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return c;
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}
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bool EtherCard::dhcpSetup (const char *hname, bool fromRam) {
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// Use during setup, as this discards all incoming requests until it returns.
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// That shouldn't be a problem, because we don't have an IP-address yet.
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// Will try 60 secs to obtain DHCP-lease.
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using_dhcp = true;
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if(hname != NULL) {
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if(fromRam) {
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strncpy(hostname, hname, DHCP_HOSTNAME_MAX_LEN);
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}
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else {
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strncpy_P(hostname, hname, DHCP_HOSTNAME_MAX_LEN);
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}
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}
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else {
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// Set a unique hostname, use Arduino-?? with last octet of mac address
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hostname[8] = toAsciiHex(mymac[5] >> 4);
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hostname[9] = toAsciiHex(mymac[5]);
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}
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dhcpState = DHCP_STATE_INIT;
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uint16_t start = millis();
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while (dhcpState != DHCP_STATE_BOUND && (uint16_t) (millis() - start) < 60000) {
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if (isLinkUp()) DhcpStateMachine(packetReceive());
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}
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updateBroadcastAddress();
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delaycnt = 0;
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return dhcpState == DHCP_STATE_BOUND ;
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}
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void EtherCard::dhcpAddOptionCallback(uint8_t option, DhcpOptionCallback callback)
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{
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dhcpCustomOptionNum = option;
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dhcpCustomOptionCallback = callback;
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}
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void EtherCard::DhcpStateMachine (uint16_t len)
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{
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#ifdef DHCPDEBUG
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if (dhcpState != DHCP_STATE_BOUND) {
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Serial.print(millis());
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Serial.print(" State: ");
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}
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switch (dhcpState) {
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case DHCP_STATE_INIT:
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Serial.println("Init");
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break;
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case DHCP_STATE_SELECTING:
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Serial.println("Selecting");
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break;
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case DHCP_STATE_REQUESTING:
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Serial.println("Requesting");
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break;
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case DHCP_STATE_RENEWING:
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Serial.println("Renew");
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
switch (dhcpState) {
|
||
|
|
|
||
|
|
case DHCP_STATE_BOUND:
|
||
|
|
//!@todo Due to millis() 49 day wrap-around, DHCP renewal may not work as expected
|
||
|
|
if (leaseTime != DHCP_INFINITE_LEASE && millis() >= leaseStart + leaseTime) {
|
||
|
|
send_dhcp_message(myip);
|
||
|
|
dhcpState = DHCP_STATE_RENEWING;
|
||
|
|
stateTimer = millis();
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
case DHCP_STATE_INIT:
|
||
|
|
currentXid = millis();
|
||
|
|
memset(myip,0,4); // force ip 0.0.0.0
|
||
|
|
send_dhcp_message(NULL);
|
||
|
|
enableBroadcast(true); //Temporarily enable broadcasts
|
||
|
|
dhcpState = DHCP_STATE_SELECTING;
|
||
|
|
stateTimer = millis();
|
||
|
|
break;
|
||
|
|
|
||
|
|
case DHCP_STATE_SELECTING:
|
||
|
|
if (dhcp_received_message_type(len, DHCP_OFFER)) {
|
||
|
|
uint8_t offeredip[4];
|
||
|
|
process_dhcp_offer(len, offeredip);
|
||
|
|
send_dhcp_message(offeredip);
|
||
|
|
dhcpState = DHCP_STATE_REQUESTING;
|
||
|
|
stateTimer = millis();
|
||
|
|
} else {
|
||
|
|
if (millis() > stateTimer + DHCP_REQUEST_TIMEOUT) {
|
||
|
|
dhcpState = DHCP_STATE_INIT;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
case DHCP_STATE_REQUESTING:
|
||
|
|
case DHCP_STATE_RENEWING:
|
||
|
|
if (dhcp_received_message_type(len, DHCP_ACK)) {
|
||
|
|
disableBroadcast(true); //Disable broadcast after temporary enable
|
||
|
|
process_dhcp_ack(len);
|
||
|
|
leaseStart = millis();
|
||
|
|
if (gwip[0] != 0) setGwIp(gwip); // why is this? because it initiates an arp request
|
||
|
|
dhcpState = DHCP_STATE_BOUND;
|
||
|
|
} else {
|
||
|
|
if (millis() > stateTimer + DHCP_REQUEST_TIMEOUT) {
|
||
|
|
dhcpState = DHCP_STATE_INIT;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
|