Diff: DhcpClient.cpp

Revision:

9:a156d3de5647

Child:

15:53715cc81c63

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DhcpClient.cpp	Tue Aug 27 15:01:10 2019 +0000
@@ -0,0 +1,526 @@
+// DHCP Library v0.3 - April 25, 2009
+// Author: Jordan Terrell - blog.jordanterrell.com
+#include <string.h>
+#include <stdlib.h>
+#include "DhcpClient.h"
+#include "utility/util.h"
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+int DhcpClient::begin(uint8_t* mac, unsigned long timeout, unsigned long responseTimeout)
+{
+    _dhcpLeaseTime = 0;
+    _dhcpT1 = 0;
+    _dhcpT2 = 0;
+    _lastCheck = 0;
+    _timeout = timeout;
+    _responseTimeout = responseTimeout;
+
+    // zero out _dhcpMacAddr
+    memset(_dhcpMacAddr, 0, 6);
+    resetDhcpLease();
+
+    memcpy((void*)_dhcpMacAddr, (void*)mac, 6);
+    _dhcp_state = STATE_DHCP_START;
+    return requestDhcpLease();
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+void DhcpClient::resetDhcpLease()
+{
+    // zero out _dhcpSubnetMask, _dhcpGatewayIp, _dhcpLocalIp, _dhcpDhcpServerIp, _dhcpDnsServerIp
+    memset(_dhcpLocalIp, 0, 5 * 4);
+}
+
+//return:0 on error, 1 if request is sent and response is received
+int DhcpClient::requestDhcpLease()
+{
+    uint8_t messageType = 0;
+
+    // Pick an initial transaction ID
+    srand(time(NULL));
+    _dhcpTransactionId = (rand() % 2000UL) + 1;
+    _dhcpInitialTransactionId = _dhcpTransactionId;
+
+    _dhcpUdpSocket.stop();
+    if (_dhcpUdpSocket.begin(DHCP_CLIENT_PORT) == 0) {
+        // Couldn't get a socket
+        return 0;
+    }
+
+    presendDhcp();
+
+    volatile int    result = 0;
+    time_t          startTime = time(NULL);
+
+    while (_dhcp_state != STATE_DHCP_LEASED) {
+        if (_dhcp_state == STATE_DHCP_START) {
+            _dhcpTransactionId++;
+
+            sendDhcpMessage(DHCP_DISCOVER, (time(NULL) - startTime));
+            _dhcp_state = STATE_DHCP_DISCOVER;
+        }
+        else
+        if (_dhcp_state == STATE_DHCP_REREQUEST) {
+            _dhcpTransactionId++;
+            sendDhcpMessage(DHCP_REQUEST, (time(NULL) - startTime));
+            _dhcp_state = STATE_DHCP_REQUEST;
+        }
+        else
+        if (_dhcp_state == STATE_DHCP_DISCOVER) {
+            uint32_t    respId;
+            messageType = parseDhcpResponse(_responseTimeout, respId);
+            if (messageType == DHCP_OFFER) {
+                // We'll use the transaction ID that the offer came with,
+                // rather than the one we were up to
+                _dhcpTransactionId = respId;
+                sendDhcpMessage(DHCP_REQUEST, (time(NULL) - startTime));
+                _dhcp_state = STATE_DHCP_REQUEST;
+            }
+        }
+        else
+        if (_dhcp_state == STATE_DHCP_REQUEST) {
+            uint32_t    respId;
+            messageType = parseDhcpResponse(_responseTimeout, respId);
+            if (messageType == DHCP_ACK) {
+                _dhcp_state = STATE_DHCP_LEASED;
+                result = 1;
+
+                //use default lease time if we didn't get it
+                if (_dhcpLeaseTime == 0) {
+                    _dhcpLeaseTime = DEFAULT_LEASE;
+                }
+
+                //calculate T1 & T2 if we didn't get it
+                if (_dhcpT1 == 0) {
+                    //T1 should be 50% of _dhcpLeaseTime
+                    _dhcpT1 = _dhcpLeaseTime >> 1;
+                }
+
+                if (_dhcpT2 == 0) {
+                    //T2 should be 87.5% (7/8ths) of _dhcpLeaseTime
+                    _dhcpT2 = _dhcpT1 << 1;
+                }
+
+                _renewInSec = _dhcpT1;
+                _rebindInSec = _dhcpT2;
+            }
+            else
+            if (messageType == DHCP_NAK)
+                _dhcp_state = STATE_DHCP_START;
+        }
+
+        if (messageType == 255) {
+            messageType = 0;
+            _dhcp_state = STATE_DHCP_START;
+        }
+
+        if ((result != 1) && ((time(NULL) - startTime) > _timeout))
+            break;
+    }
+
+    // We're done with the socket now
+    _dhcpUdpSocket.stop();
+    _dhcpTransactionId++;
+
+    return result;
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+void DhcpClient::presendDhcp()
+{ }
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+void DhcpClient::sendDhcpMessage(uint8_t messageType, uint16_t secondsElapsed)
+{
+    uint8_t buffer[32];
+    memset(buffer, 0, 32);
+
+    IpAddress   dest_addr(255, 255, 255, 255);  // Broadcast address
+
+    if (-1 == _dhcpUdpSocket.beginPacket(dest_addr, DHCP_SERVER_PORT)) {
+        // FIXME Need to return errors
+        return;
+    }
+
+    buffer[0] = DHCP_BOOTREQUEST;               // op
+    buffer[1] = DHCP_HTYPE10MB;                 // htype
+    buffer[2] = DHCP_HLENETHERNET;              // hlen
+    buffer[3] = DHCP_HOPS;                      // hops
+    // xid
+    unsigned long   xid = htonl(_dhcpTransactionId);
+    memcpy(buffer + 4, &(xid), 4);
+
+    // 8, 9 - seconds elapsed
+    buffer[8] = ((secondsElapsed & 0xff00) >> 8);
+    buffer[9] = (secondsElapsed & 0x00ff);
+
+    // flags
+    unsigned short  flags = htons(DHCP_FLAGSBROADCAST);
+    memcpy(buffer + 10, &(flags), 2);
+
+    // ciaddr: already zeroed
+    // yiaddr: already zeroed
+    // siaddr: already zeroed
+    // giaddr: already zeroed
+    //put data in W5100 transmit buffer
+    _dhcpUdpSocket.write(buffer, 28);
+
+    memset(buffer, 0, 32);                      // clear local buffer
+    memcpy(buffer, _dhcpMacAddr, 6);            // chaddr
+    //put data in W5100 transmit buffer
+    _dhcpUdpSocket.write(buffer, 16);
+
+    memset(buffer, 0, 32);                      // clear local buffer
+    // leave zeroed out for sname && file
+    // put in W5100 transmit buffer x 6 (192 bytes)
+    for (int i = 0; i < 6; i++) {
+        _dhcpUdpSocket.write(buffer, 32);
+    }
+
+    // OPT - Magic Cookie
+    buffer[0] = (uint8_t) ((MAGIC_COOKIE >> 24) & 0xFF);
+    buffer[1] = (uint8_t) ((MAGIC_COOKIE >> 16) & 0xFF);
+    buffer[2] = (uint8_t) ((MAGIC_COOKIE >> 8) & 0xFF);
+    buffer[3] = (uint8_t) (MAGIC_COOKIE & 0xFF);
+
+    // OPT - message type
+    buffer[4] = dhcpMessageType;
+    buffer[5] = 0x01;
+    buffer[6] = messageType;                    //DHCP_REQUEST;
+    // OPT - client identifier
+    buffer[7] = dhcpClientIdentifier;
+    buffer[8] = 0x07;
+    buffer[9] = 0x01;
+    memcpy(buffer + 10, _dhcpMacAddr, 6);
+
+    // OPT - host name
+    buffer[16] = hostName;
+    buffer[17] = strlen(HOST_NAME) + 6;         // length of hostname + last 3 bytes of mac address
+    strcpy((char*) &(buffer[18]), HOST_NAME);
+
+    printByte((char*) &(buffer[24]), _dhcpMacAddr[3]);
+    printByte((char*) &(buffer[26]), _dhcpMacAddr[4]);
+    printByte((char*) &(buffer[28]), _dhcpMacAddr[5]);
+
+    //put data in W5100 transmit buffer
+    _dhcpUdpSocket.write(buffer, 30);
+
+    if (messageType == DHCP_REQUEST) {
+        buffer[0] = dhcpRequestedIPaddr;
+        buffer[1] = 0x04;
+        buffer[2] = _dhcpLocalIp[0];
+        buffer[3] = _dhcpLocalIp[1];
+        buffer[4] = _dhcpLocalIp[2];
+        buffer[5] = _dhcpLocalIp[3];
+
+        buffer[6] = dhcpServerIdentifier;
+        buffer[7] = 0x04;
+
+        //buffer[8] = _dhcpDhcpServerIp[0];
+        buffer[8] = _dhcpLocalIp[0];
+        buffer[9] = _dhcpDhcpServerIp[1];
+        buffer[10] = _dhcpDhcpServerIp[2];
+        buffer[11] = _dhcpDhcpServerIp[3];
+
+        //put data in W5100 transmit buffer
+        _dhcpUdpSocket.write(buffer, 12);
+    }
+
+    buffer[0] = dhcpParamRequest;
+    buffer[1] = 0x06;
+    buffer[2] = subnetMask;
+    buffer[3] = routersOnSubnet;
+    buffer[4] = dns;
+    buffer[5] = domainName;
+    buffer[6] = dhcpT1value;
+    buffer[7] = dhcpT2value;
+    buffer[8] = endOption;
+
+    //put data in W5100 transmit buffer
+    _dhcpUdpSocket.write(buffer, 9);
+
+    _dhcpUdpSocket.endPacket();
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+uint8_t DhcpClient::parseDhcpResponse(unsigned long responseTimeout, uint32_t& transactionId)
+{
+    volatile uint8_t    type = 0;
+    uint8_t             opt_len = 0;
+
+    unsigned long       startTime = time(NULL);
+
+    while (_dhcpUdpSocket.parsePacket() <= 0) {
+        if ((time(NULL) - startTime) > responseTimeout) {
+            return 255;
+        }
+
+        wait_ms(50);
+    }
+
+    // start reading in the packet
+    RIP_MSG_FIXED   fixedMsg;
+    _dhcpUdpSocket.read((uint8_t*) &fixedMsg, sizeof(RIP_MSG_FIXED));
+
+    if (fixedMsg.op == DHCP_BOOTREPLY && _dhcpUdpSocket.remotePort() == DHCP_SERVER_PORT) {
+        transactionId = ntohl(fixedMsg.xid);
+        if
+        (
+            memcmp(fixedMsg.chaddr, _dhcpMacAddr, 6) != 0 ||
+            (transactionId < _dhcpInitialTransactionId) ||
+            (transactionId > _dhcpTransactionId)
+        ) {
+            // Need to read the rest of the packet here regardless
+            _dhcpUdpSocket.flush();
+            return 0;
+        }
+
+        memcpy(_dhcpLocalIp, fixedMsg.yiaddr, 4);
+
+        // Skip to the option part
+        // Doing this a byte at a time so we don't have to put a big buffer
+        // on the stack (as we don't have lots of memory lying around)
+        for (int i = 0; i < (240 - (int)sizeof(RIP_MSG_FIXED)); i++) {
+            _dhcpUdpSocket.read();  // we don't care about the returned byte
+        }
+
+        while (_dhcpUdpSocket.available() > 0) {
+            switch (_dhcpUdpSocket.read()) {
+                case endOption:
+                    break;
+
+                case padOption:
+                    break;
+
+                case dhcpMessageType:
+                    opt_len = _dhcpUdpSocket.read();
+                    type = _dhcpUdpSocket.read();
+                    break;
+
+                case subnetMask:
+                    opt_len = _dhcpUdpSocket.read();
+                    _dhcpUdpSocket.read(_dhcpSubnetMask, 4);
+                    break;
+
+                case routersOnSubnet:
+                    opt_len = _dhcpUdpSocket.read();
+                    _dhcpUdpSocket.read(_dhcpGatewayIp, 4);
+                    for (int i = 0; i < opt_len - 4; i++) {
+                        _dhcpUdpSocket.read();
+                    }
+                    break;
+
+                case dns:
+                    opt_len = _dhcpUdpSocket.read();
+                    _dhcpUdpSocket.read(_dhcpDnsServerIp, 4);
+                    for (int i = 0; i < opt_len - 4; i++) {
+                        _dhcpUdpSocket.read();
+                    }
+                    break;
+
+                case dhcpServerIdentifier:
+                    opt_len = _dhcpUdpSocket.read();
+                    if (*((uint32_t*)_dhcpDhcpServerIp) == 0 || IpAddress(_dhcpDhcpServerIp) == _dhcpUdpSocket.remoteIP()) {
+                        _dhcpUdpSocket.read(_dhcpDhcpServerIp, sizeof(_dhcpDhcpServerIp));
+                    }
+                    else {
+                        // Skip over the rest of this option
+                        while (opt_len--) {
+                            _dhcpUdpSocket.read();
+                        }
+                    }
+                    break;
+
+                case dhcpT1value:
+                    opt_len = _dhcpUdpSocket.read();
+                    _dhcpUdpSocket.read((uint8_t*) &_dhcpT1, sizeof(_dhcpT1));
+                    _dhcpT1 = ntohl(_dhcpT1);
+                    break;
+
+                case dhcpT2value:
+                    opt_len = _dhcpUdpSocket.read();
+                    _dhcpUdpSocket.read((uint8_t*) &_dhcpT2, sizeof(_dhcpT2));
+                    _dhcpT2 = ntohl(_dhcpT2);
+                    break;
+
+                case dhcpIPaddrLeaseTime:
+                    opt_len = _dhcpUdpSocket.read();
+                    _dhcpUdpSocket.read((uint8_t*) &_dhcpLeaseTime, sizeof(_dhcpLeaseTime));
+                    _dhcpLeaseTime = ntohl(_dhcpLeaseTime);
+                    _renewInSec = _dhcpLeaseTime;
+                    break;
+
+                default:
+                    opt_len = _dhcpUdpSocket.read();
+
+                    // Skip over the rest of this option
+                    while (opt_len--) {
+                        _dhcpUdpSocket.read();
+                    }
+                    break;
+            }
+        }
+    }
+
+    // Need to skip to end of the packet regardless here
+    _dhcpUdpSocket.flush();
+
+    return type;
+}
+
+/*
+    returns:
+    0/DHCP_CHECK_NONE: nothing happened
+    1/DHCP_CHECK_RENEW_FAIL: renew failed
+    2/DHCP_CHECK_RENEW_OK: renew success
+    3/DHCP_CHECK_REBIND_FAIL: rebind fail
+    4/DHCP_CHECK_REBIND_OK: rebind success
+*/
+int DhcpClient::checkLease()
+{
+    time_t          now = time(NULL);
+    volatile int    rc = DHCP_CHECK_NONE;
+    if (_lastCheck != 0) {
+        //calc how many ms past the timeout we are
+        time_t  factor = now - _secTimeout;
+
+        //if on or passed the timeout, reduce the counters
+        if (factor >= 0) {
+            //next timeout should be now plus 1s
+            _secTimeout = now + 1;
+
+            //reduce the counters by that mouch
+            //if we can assume that the cycle time (factor) is fairly constant
+            //and if the remainder is less than cycle time * 2
+            //do it early instead of late
+            if (_renewInSec < factor * 2)
+                _renewInSec = 0;
+            else
+                _renewInSec -= factor;
+
+            if (_rebindInSec < factor * 2)
+                _rebindInSec = 0;
+            else
+                _rebindInSec -= factor;
+        }
+
+        //if we have a lease but should renew, do it
+        if (_dhcp_state == STATE_DHCP_LEASED && _renewInSec <= 0) {
+            _dhcp_state = STATE_DHCP_REREQUEST;
+            rc = 1 + requestDhcpLease();
+        }
+
+        //if we have a lease or is renewing but should bind, do it
+        if ((_dhcp_state == STATE_DHCP_LEASED || _dhcp_state == STATE_DHCP_START) && _rebindInSec <= 0) {
+            //this should basically restart completely
+            _dhcp_state = STATE_DHCP_START;
+            resetDhcpLease();
+            rc = 3 + requestDhcpLease();
+        }
+    }
+    else {
+        _secTimeout = now + 1;
+    }
+
+    _lastCheck = now;
+    return rc;
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+IpAddress DhcpClient::getLocalIp()
+{
+    return IpAddress(_dhcpLocalIp);
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+IpAddress DhcpClient::getSubnetMask()
+{
+    return IpAddress(_dhcpSubnetMask);
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+IpAddress DhcpClient::getGatewayIp()
+{
+    return IpAddress(_dhcpGatewayIp);
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+IpAddress DhcpClient::getDhcpServerIp()
+{
+    return IpAddress(_dhcpDhcpServerIp);
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+IpAddress DhcpClient::getDnsServerIp()
+{
+    return IpAddress(_dhcpDnsServerIp);
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+void DhcpClient::printByte(char* buf, uint8_t n)
+{
+    char*   str = &buf[1];
+    buf[0] = '0';
+    do {
+        unsigned long   m = n;
+        n /= 16;
+
+        char    c = m - 16 * n;
+        *str-- = c < 10 ? c + '0' : c + 'A' - 10;
+    } while (n);
+}