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// DHCP look-up functions based on the udp client
// http://www.ietf.org/rfc/rfc2131.txt
//
// Author: Andrew Lindsay
// Rewritten and optimized by Jean-Claude Wippler, http://jeelabs.org/
//
// Rewritten dhcpStateMachine by Chris van den Hooven
// as to implement dhcp-renew when lease expires (jun 2012)
//
// Various modifications and bug fixes contributed by Victor Aprea (oct 2012)
//
// Copyright: GPL V2
// See http://www.gnu.org/licenses/gpl.html
//#define DHCPDEBUG
#include "EtherCard.h"
#include "net.h"
#define gPB ether.buffer
#define DHCP_BOOTREQUEST 1
#define DHCP_BOOTRESPONSE 2
// DHCP Message Type (option 53) (ref RFC 2132)
#define DHCP_DISCOVER 1
#define DHCP_OFFER 2
#define DHCP_REQUEST 3
#define DHCP_DECLINE 4
#define DHCP_ACK 5
#define DHCP_NAK 6
#define DHCP_RELEASE 7
// DHCP States for access in applications (ref RFC 2131)
enum {
DHCP_STATE_INIT,
DHCP_STATE_SELECTING,
DHCP_STATE_REQUESTING,
DHCP_STATE_BOUND,
DHCP_STATE_RENEWING,
};
/*
op 1 Message op code / message type.
1 = BOOTREQUEST, 2 = BOOTREPLY
htype 1 Hardware address type, see ARP section in "Assigned
Numbers" RFC; e.g., '1' = 10mb ethernet.
hlen 1 Hardware address length (e.g. '6' for 10mb
ethernet).
hops 1 Client sets to zero, optionally used by relay agents
when booting via a relay agent.
xid 4 Transaction ID, a random number chosen by the
client, used by the client and server to associate
messages and responses between a client and a
server.
secs 2 Filled in by client, seconds elapsed since client
began address acquisition or renewal process.
flags 2 Flags (see figure 2).
ciaddr 4 Client IP address; only filled in if client is in
BOUND, RENEW or REBINDING state and can respond
to ARP requests.
yiaddr 4 'your' (client) IP address.
siaddr 4 IP address of next server to use in bootstrap;
returned in DHCPOFFER, DHCPACK by server.
giaddr 4 Relay agent IP address, used in booting via a
relay agent.
chaddr 16 Client hardware address.
sname 64 Optional server host name, null terminated string.
file 128 Boot file name, null terminated string; "generic"
name or null in DHCPDISCOVER, fully qualified
directory-path name in DHCPOFFER.
options var Optional parameters field. See the options
documents for a list of defined options.
*/
// size 236
typedef struct {
byte op, htype, hlen, hops;
uint32_t xid;
uint16_t secs, flags;
byte ciaddr[IP_LEN], yiaddr[IP_LEN], siaddr[IP_LEN], giaddr[IP_LEN];
byte chaddr[16], sname[64], file[128];
// options
} DHCPdata;
#define DHCP_SERVER_PORT 67
#define DHCP_CLIENT_PORT 68
// timeouts im ms
#define DHCP_REQUEST_TIMEOUT 10000
#define DHCP_HOSTNAME_MAX_LEN 32
// RFC 2132 Section 3.3:
// The time value of 0xffffffff is reserved to represent "infinity".
#define DHCP_INFINITE_LEASE 0xffffffff
static byte dhcpState = DHCP_STATE_INIT;
static char hostname[DHCP_HOSTNAME_MAX_LEN] = "Arduino-ENC28j60-00"; // Last two characters will be filled by last 2 MAC digits ;
static uint32_t currentXid;
static uint32_t stateTimer;
static uint32_t leaseStart;
static uint32_t leaseTime;
static byte* bufPtr;
static uint8_t dhcpCustomOptionNum = 0;
static DhcpOptionCallback dhcpCustomOptionCallback = NULL;
extern uint8_t allOnes[];// = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
static void addToBuf (byte b) {
*bufPtr++ = b;
}
static void addBytes (byte len, const byte* data) {
while (len-- > 0)
addToBuf(*data++);
}
static void addOption (byte opt, byte len, const byte* data) {
addToBuf(opt);
addToBuf(len);
addBytes(len, data);
}
// Main DHCP sending function
// implemented
// state / msgtype
// INIT / DHCPDISCOVER
// SELECTING / DHCPREQUEST
// BOUND (RENEWING) / DHCPREQUEST
// ----------------------------------------------------------
// | |SELECTING |RENEWING |INIT |
// ----------------------------------------------------------
// |broad/unicast |broadcast |unicast |broadcast |
// |server-ip |MUST |MUST NOT |MUST NOT | option 54
// |requested-ip |MUST |MUST NOT |MUST NOT | option 50
// |ciaddr |zero |IP address |zero |
// ----------------------------------------------------------
// options used (both send/receive)
#define DHCP_OPT_SUBNET_MASK 1
#define DHCP_OPT_ROUTERS 3
#define DHCP_OPT_DOMAIN_NAME_SERVERS 6
#define DHCP_OPT_HOSTNAME 12
#define DHCP_OPT_REQUESTED_ADDRESS 50
#define DHCP_OPT_LEASE_TIME 51
#define DHCP_OPT_MESSAGE_TYPE 53
#define DHCP_OPT_SERVER_IDENTIFIER 54
#define DHCP_OPT_PARAMETER_REQUEST_LIST 55
#define DHCP_OPT_RENEWAL_TIME 58
#define DHCP_OPT_CLIENT_IDENTIFIER 61
#define DHCP_OPT_END 255
#define DHCP_HTYPE_ETHER 1
static void send_dhcp_message(uint8_t *requestip) {
memset(gPB, 0, UDP_DATA_P + sizeof( DHCPdata ));
EtherCard::udpPrepare(DHCP_CLIENT_PORT,
(dhcpState == DHCP_STATE_BOUND ? EtherCard::dhcpip : allOnes),
DHCP_SERVER_PORT);
// If we ever don't do this, the DHCP renewal gets sent to whatever random
// destmacaddr was used by other code. Rather than cache the MAC address of
// the DHCP server, just force a broadcast here in all cases.
EtherCard::copyMac(gPB + ETH_DST_MAC, allOnes); //force broadcast mac
// Build DHCP Packet from buf[UDP_DATA_P]
DHCPdata *dhcpPtr = (DHCPdata*) (gPB + UDP_DATA_P);
dhcpPtr->op = DHCP_BOOTREQUEST;
dhcpPtr->htype = 1;
dhcpPtr->hlen = 6;
dhcpPtr->xid = currentXid;
if (dhcpState == DHCP_STATE_BOUND) {
EtherCard::copyIp(dhcpPtr->ciaddr, EtherCard::myip);
}
EtherCard::copyMac(dhcpPtr->chaddr, EtherCard::mymac);
// options defined as option, length, value
bufPtr = gPB + UDP_DATA_P + sizeof( DHCPdata );
// DHCP magic cookie
static const byte cookie[] PROGMEM = { 0x63,0x82,0x53,0x63 };
for (byte i = 0; i < sizeof(cookie); i++)
addToBuf(pgm_read_byte(&cookie[i]));
addToBuf(DHCP_OPT_MESSAGE_TYPE); // DHCP_STATE_SELECTING, DHCP_STATE_REQUESTING
addToBuf(1); // Length
addToBuf(dhcpState == DHCP_STATE_INIT ? DHCP_DISCOVER : DHCP_REQUEST);
// Client Identifier Option, this is the client mac address
addToBuf(DHCP_OPT_CLIENT_IDENTIFIER);
addToBuf(1 + ETH_LEN); // Length (hardware type + client MAC)
addToBuf(DHCP_HTYPE_ETHER);
addBytes(ETH_LEN, EtherCard::mymac);
if (hostname[0]) {
addOption(DHCP_OPT_HOSTNAME, strlen(hostname), (byte*) hostname);
}
if (requestip != NULL) {
addOption(DHCP_OPT_REQUESTED_ADDRESS, IP_LEN, requestip);
addOption(DHCP_OPT_SERVER_IDENTIFIER, IP_LEN, EtherCard::dhcpip);
}
// Additional info in parameter list - minimal list for what we need
byte len = 3;
if (dhcpCustomOptionNum)
len++;
addToBuf(DHCP_OPT_PARAMETER_REQUEST_LIST);
addToBuf(len); // Length
addToBuf(DHCP_OPT_SUBNET_MASK);
addToBuf(DHCP_OPT_ROUTERS);
addToBuf(DHCP_OPT_DOMAIN_NAME_SERVERS);
if (dhcpCustomOptionNum)
addToBuf(dhcpCustomOptionNum); // Custom option
addToBuf(DHCP_OPT_END);
// packet size will be under 300 bytes
EtherCard::udpTransmit((bufPtr - gPB) - UDP_DATA_P);
}
static void process_dhcp_offer(uint16_t len, uint8_t *offeredip) {
// Map struct onto payload
DHCPdata *dhcpPtr = (DHCPdata*) (gPB + UDP_DATA_P);
// Offered IP address is in yiaddr
EtherCard::copyIp(offeredip, dhcpPtr->yiaddr);
// Search for the server IP
byte *ptr = (byte*) (dhcpPtr + 1) + 4;
do {
byte option = *ptr++;
byte optionLen = *ptr++;
if (option == DHCP_OPT_SERVER_IDENTIFIER) {
EtherCard::copyIp(EtherCard::dhcpip, ptr);
break;
}
ptr += optionLen;
} while (ptr < gPB + len);
}
static void process_dhcp_ack(uint16_t len) {
// Map struct onto payload
DHCPdata *dhcpPtr = (DHCPdata*) (gPB + UDP_DATA_P);
// Allocated IP address is in yiaddr
EtherCard::copyIp(EtherCard::myip, dhcpPtr->yiaddr);
// Scan through variable length option list identifying options we want
byte *ptr = (byte*) (dhcpPtr + 1) + 4;
bool done = false;
do {
byte option = *ptr++;
byte optionLen = *ptr++;
switch (option) {
case DHCP_OPT_SUBNET_MASK:
EtherCard::copyIp(EtherCard::netmask, ptr);
break;
case DHCP_OPT_ROUTERS:
EtherCard::copyIp(EtherCard::gwip, ptr);
break;
case DHCP_OPT_DOMAIN_NAME_SERVERS:
EtherCard::copyIp(EtherCard::dnsip, ptr);
break;
case DHCP_OPT_LEASE_TIME:
case DHCP_OPT_RENEWAL_TIME:
leaseTime = 0;
for (byte i = 0; i<4; i++)
leaseTime = (leaseTime << 8) + ptr[i];
if (leaseTime != DHCP_INFINITE_LEASE) {
leaseTime *= 1000; // milliseconds
}
break;
case DHCP_OPT_END:
done = true;
break;
default: {
// Is is a custom configured option?
if (dhcpCustomOptionCallback && option == dhcpCustomOptionNum) {
dhcpCustomOptionCallback(option, ptr, optionLen);
}
}
}
ptr += optionLen;
} while (!done && ptr < gPB + len);
}
static bool dhcp_received_message_type (uint16_t len, byte msgType) {
// Map struct onto payload
DHCPdata *dhcpPtr = (DHCPdata*) (gPB + UDP_DATA_P);
if (len >= 70 && gPB[UDP_SRC_PORT_L_P] == DHCP_SERVER_PORT &&
dhcpPtr->xid == currentXid ) {
byte *ptr = (byte*) (dhcpPtr + 1) + 4;
do {
byte option = *ptr++;
byte optionLen = *ptr++;
if(option == DHCP_OPT_MESSAGE_TYPE && *ptr == msgType ) {
return true;
}
ptr += optionLen;
} while (ptr < gPB + len);
}
return false;
}
static char toAsciiHex(byte b) {
char c = b & 0x0f;
c += (c <= 9) ? '0' : 'A'-10;
return c;
}
bool EtherCard::dhcpSetup (const char *hname, bool fromRam) {
// Use during setup, as this discards all incoming requests until it returns.
// That shouldn't be a problem, because we don't have an IP-address yet.
// Will try 60 secs to obtain DHCP-lease.
using_dhcp = true;
if(hname != NULL) {
if(fromRam) {
strncpy(hostname, hname, DHCP_HOSTNAME_MAX_LEN);
}
else {
strncpy_P(hostname, hname, DHCP_HOSTNAME_MAX_LEN);
}
}
else {
// Set a unique hostname, use Arduino-?? with last octet of mac address
hostname[strlen(hostname) - 2] = toAsciiHex(mymac[5] >> 4); // Appends mac to last 2 digits of the hostname
hostname[strlen(hostname) - 1] = toAsciiHex(mymac[5]); // Even if it's smaller than the maximum <thus, strlen(hostname)>
}
dhcpState = DHCP_STATE_INIT;
uint16_t start = millis();
while (dhcpState != DHCP_STATE_BOUND && uint16_t(millis()) - start < 60000) {
if (isLinkUp()) DhcpStateMachine(packetReceive());
}
updateBroadcastAddress();
delaycnt = 0;
return dhcpState == DHCP_STATE_BOUND ;
}
void EtherCard::dhcpAddOptionCallback(uint8_t option, DhcpOptionCallback callback)
{
dhcpCustomOptionNum = option;
dhcpCustomOptionCallback = callback;
}
void EtherCard::DhcpStateMachine (uint16_t len)
{
#ifdef DHCPDEBUG
if (dhcpState != DHCP_STATE_BOUND) {
Serial.print(millis());
Serial.print(" State: ");
}
switch (dhcpState) {
case DHCP_STATE_INIT:
Serial.println("Init");
break;
case DHCP_STATE_SELECTING:
Serial.println("Selecting");
break;
case DHCP_STATE_REQUESTING:
Serial.println("Requesting");
break;
case DHCP_STATE_RENEWING:
Serial.println("Renew");
break;
}
#endif
switch (dhcpState) {
case DHCP_STATE_BOUND:
//!@todo Due to millis() wrap-around, DHCP renewal may not work if leaseTime is larger than 49days
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,IP_LEN); // 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[IP_LEN];
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;
}
}