Andrew Boyson / net

A stack which works with or without an Mbed os library. Provides IPv4 or IPv6 with a full 1500 byte buffer.

Dependents:   oldheating gps motorhome heating

udp/dhcp.cpp@59:e0e556c8bd46, 2017-12-14 (annotated)

Committer:
andrewboyson
Date:
Thu Dec 14 20:55:40 2017 +0000
Revision:
59:e0e556c8bd46
Parent:
49:1a6336f2b3f9 
Added buffer length to help avoid over runs

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 37:793b39683406 1 #include "mbed.h"
andrewboyson 37:793b39683406 2 #include "log.h"
andrewboyson 43:bc028d5a6424 3 #include "clock.h"
andrewboyson 37:793b39683406 4 #include "net.h"
andrewboyson 37:793b39683406 5 #include "action.h"
andrewboyson 37:793b39683406 6 #include "eth.h"
andrewboyson 49:1a6336f2b3f9 7 #include "ip4addr.h"
andrewboyson 37:793b39683406 8 #include "mac.h"
andrewboyson 37:793b39683406 9 #include "udp.h"
andrewboyson 10:f0854784e960 10
andrewboyson 37:793b39683406 11 bool DhcpTrace = false;
andrewboyson 10:f0854784e960 12
andrewboyson 10:f0854784e960 13 #define REQUEST 1
andrewboyson 10:f0854784e960 14 #define REPLY 2
andrewboyson 10:f0854784e960 15
andrewboyson 10:f0854784e960 16 #define DHCPDISCOVER 1
andrewboyson 10:f0854784e960 17 #define DHCPOFFER 2
andrewboyson 10:f0854784e960 18 #define DHCPREQUEST 3
andrewboyson 10:f0854784e960 19 #define DHCPDECLINE 4
andrewboyson 10:f0854784e960 20 #define DHCPACK 5
andrewboyson 10:f0854784e960 21 #define DHCPNAK 6
andrewboyson 10:f0854784e960 22 #define DHCPRELEASE 7
andrewboyson 10:f0854784e960 23 #define DHCPINFORM 8
andrewboyson 10:f0854784e960 24
andrewboyson 10:f0854784e960 25 #define ID 75648
andrewboyson 10:f0854784e960 26 #define COOKIE 0x63825363
andrewboyson 10:f0854784e960 27 #define HEADER_LENGTH 240
andrewboyson 10:f0854784e960 28
andrewboyson 10:f0854784e960 29 __packed struct header
andrewboyson 10:f0854784e960 30 {
andrewboyson 10:f0854784e960 31 uint8_t op;
andrewboyson 10:f0854784e960 32 uint8_t htype;
andrewboyson 10:f0854784e960 33 uint8_t hlen;
andrewboyson 10:f0854784e960 34 uint8_t hops;
andrewboyson 10:f0854784e960 35
andrewboyson 10:f0854784e960 36 uint32_t xid;
andrewboyson 10:f0854784e960 37
andrewboyson 10:f0854784e960 38 uint16_t secs;
andrewboyson 10:f0854784e960 39 uint16_t flags;
andrewboyson 10:f0854784e960 40
andrewboyson 10:f0854784e960 41 uint32_t ciaddr;
andrewboyson 10:f0854784e960 42 uint32_t yiaddr;
andrewboyson 10:f0854784e960 43 uint32_t siaddr;
andrewboyson 10:f0854784e960 44 uint32_t giaddr;
andrewboyson 10:f0854784e960 45
andrewboyson 10:f0854784e960 46 uint8_t chaddr[16];
andrewboyson 10:f0854784e960 47
andrewboyson 10:f0854784e960 48 char legacy[192];
andrewboyson 10:f0854784e960 49
andrewboyson 10:f0854784e960 50 uint32_t cookie;
andrewboyson 10:f0854784e960 51 };
andrewboyson 10:f0854784e960 52
andrewboyson 10:f0854784e960 53 #define REPEAT_DELAY_TIME 60
andrewboyson 10:f0854784e960 54 static uint32_t delayTime = 10000000; //Reset whenever a message is sent and blocks another send until count exceeds REPEAT_DELAY_TIME
andrewboyson 43:bc028d5a6424 55 uint32_t DhcpElapsedTime = 0; //Reset whenever an IP address request has been acknowledged
andrewboyson 43:bc028d5a6424 56 void DhcpMain()
andrewboyson 10:f0854784e960 57 {
andrewboyson 43:bc028d5a6424 58 if (ClockTicked)
andrewboyson 43:bc028d5a6424 59 {
andrewboyson 43:bc028d5a6424 60 DhcpElapsedTime++;
andrewboyson 43:bc028d5a6424 61 delayTime++;
andrewboyson 43:bc028d5a6424 62 }
andrewboyson 10:f0854784e960 63 }
andrewboyson 10:f0854784e960 64
andrewboyson 10:f0854784e960 65 static uint8_t dhcpMessageType = 0;
andrewboyson 10:f0854784e960 66 uint32_t DhcpLeaseTime = 0;
andrewboyson 10:f0854784e960 67 uint32_t DhcpServer = 0;
andrewboyson 10:f0854784e960 68 uint32_t DhcpRouter = 0;
andrewboyson 10:f0854784e960 69 uint32_t DhcpSubnetMask = 0;
andrewboyson 10:f0854784e960 70 uint32_t DhcpNtp = 0;
andrewboyson 10:f0854784e960 71 uint32_t DhcpRenewalT1 = 0;
andrewboyson 10:f0854784e960 72 uint32_t DhcpRenewalT2 = 0;
andrewboyson 10:f0854784e960 73 uint32_t DhcpBroadcastIp = 0;
andrewboyson 10:f0854784e960 74 uint32_t DhcpLocalIp = 0;
andrewboyson 10:f0854784e960 75 uint32_t DhcpDnsServer = 0;
andrewboyson 10:f0854784e960 76 char DhcpDomainName[20];
andrewboyson 10:f0854784e960 77 char DhcpHostName[20];
andrewboyson 44:83ce5ace337b 78
andrewboyson 44:83ce5ace337b 79 bool DhcpIpNeedsToBeRouted(uint32_t ip)
andrewboyson 44:83ce5ace337b 80 {
andrewboyson 44:83ce5ace337b 81 return ip & DhcpSubnetMask != DhcpBroadcastIp & DhcpSubnetMask;
andrewboyson 44:83ce5ace337b 82 }
andrewboyson 44:83ce5ace337b 83
andrewboyson 10:f0854784e960 84 static uint32_t readOption32(char** pp)
andrewboyson 10:f0854784e960 85 {
andrewboyson 10:f0854784e960 86 uint32_t value = 0;
andrewboyson 10:f0854784e960 87 char* p = *pp;
andrewboyson 10:f0854784e960 88 int len = *++p;
andrewboyson 10:f0854784e960 89 if (len >= 4)
andrewboyson 10:f0854784e960 90 {
andrewboyson 10:f0854784e960 91 value = *++p << 24;
andrewboyson 10:f0854784e960 92 value |= *++p << 16;
andrewboyson 10:f0854784e960 93 value |= *++p << 8;
andrewboyson 10:f0854784e960 94 value |= *++p << 0;
andrewboyson 10:f0854784e960 95 }
andrewboyson 10:f0854784e960 96 *pp += len + 1;
andrewboyson 10:f0854784e960 97 return value;
andrewboyson 10:f0854784e960 98 }
andrewboyson 10:f0854784e960 99 static uint32_t readIp(char** pp)
andrewboyson 10:f0854784e960 100 {
andrewboyson 10:f0854784e960 101 uint32_t value = 0;
andrewboyson 10:f0854784e960 102 char* p = *pp;
andrewboyson 10:f0854784e960 103 int len = *++p;
andrewboyson 10:f0854784e960 104 if (len >= 4)
andrewboyson 10:f0854784e960 105 {
andrewboyson 10:f0854784e960 106 value = *++p << 0;
andrewboyson 10:f0854784e960 107 value |= *++p << 8;
andrewboyson 10:f0854784e960 108 value |= *++p << 16;
andrewboyson 10:f0854784e960 109 value |= *++p << 24;
andrewboyson 10:f0854784e960 110 }
andrewboyson 10:f0854784e960 111 *pp += len + 1;
andrewboyson 10:f0854784e960 112 return value;
andrewboyson 10:f0854784e960 113 }
andrewboyson 10:f0854784e960 114 static void readString(char** pp, char* pText)
andrewboyson 10:f0854784e960 115 {
andrewboyson 10:f0854784e960 116 char* p = *pp;
andrewboyson 10:f0854784e960 117 int len = *++p;
andrewboyson 10:f0854784e960 118 for (int i = 0; i < len; i++) pText[i] = *++p;
andrewboyson 10:f0854784e960 119 *pp += len + 1;
andrewboyson 10:f0854784e960 120 }
andrewboyson 10:f0854784e960 121 static void readOptions(int size, char * pOptions)
andrewboyson 10:f0854784e960 122 {
andrewboyson 10:f0854784e960 123 int len = 0;
andrewboyson 10:f0854784e960 124 char* p = pOptions;
andrewboyson 10:f0854784e960 125 char* pE = pOptions + size;
andrewboyson 10:f0854784e960 126 while( p < pE)
andrewboyson 10:f0854784e960 127 {
andrewboyson 10:f0854784e960 128 switch (*p)
andrewboyson 10:f0854784e960 129 {
andrewboyson 10:f0854784e960 130 case 0: break; //NOP
andrewboyson 10:f0854784e960 131 case 255: return; //End of options
andrewboyson 10:f0854784e960 132 case 1: DhcpSubnetMask = readIp(&p); break; //Subnet Mask
andrewboyson 10:f0854784e960 133 case 3: DhcpRouter = readIp(&p); break; //Router
andrewboyson 10:f0854784e960 134 case 6: DhcpDnsServer = readIp(&p); break; //DNS server
andrewboyson 10:f0854784e960 135 case 12: readString(&p, DhcpHostName); break; //Host name
andrewboyson 10:f0854784e960 136 case 15: readString(&p, DhcpDomainName); break; //Domain name
andrewboyson 10:f0854784e960 137 case 19: len = *++p; p+= len; break; //IP forwarding yes/no
andrewboyson 10:f0854784e960 138 case 28: DhcpBroadcastIp = readIp(&p); break; //Broadcast IP
andrewboyson 10:f0854784e960 139 case 42: DhcpNtp = readIp(&p); break; //NTP
andrewboyson 10:f0854784e960 140 case 44: len = *++p; p+= len; break; //NetBIOS name server
andrewboyson 10:f0854784e960 141 case 45: len = *++p; p+= len; break; //NetBIOS datagram server
andrewboyson 10:f0854784e960 142 case 46: len = *++p; p+= len; break; //NetBIOS node type
andrewboyson 10:f0854784e960 143 case 47: len = *++p; p+= len; break; //NetBIOS scope
andrewboyson 10:f0854784e960 144 case 53: len = *++p; dhcpMessageType = *++p; break; //DHCP message type
andrewboyson 10:f0854784e960 145 case 51: DhcpLeaseTime = readOption32(&p); break; //Address lease time
andrewboyson 10:f0854784e960 146 case 54: DhcpServer = readIp(&p); break; //DHCP server
andrewboyson 10:f0854784e960 147 case 58: DhcpRenewalT1 = readOption32(&p); break; //T1
andrewboyson 10:f0854784e960 148 case 59: DhcpRenewalT2 = readOption32(&p); break; //T2
andrewboyson 10:f0854784e960 149 default:
andrewboyson 37:793b39683406 150 if (DhcpTrace) LogTimeF("Ignoring option %d\r\n", *p);
andrewboyson 10:f0854784e960 151 len = *++p;
andrewboyson 10:f0854784e960 152 p += len;
andrewboyson 10:f0854784e960 153 return;
andrewboyson 10:f0854784e960 154 }
andrewboyson 10:f0854784e960 155 p++;
andrewboyson 10:f0854784e960 156 }
andrewboyson 10:f0854784e960 157 }
andrewboyson 10:f0854784e960 158 static void writeIp(uint8_t code, uint32_t value, char** pp)
andrewboyson 10:f0854784e960 159 {
andrewboyson 10:f0854784e960 160 if (!value) return;
andrewboyson 10:f0854784e960 161
andrewboyson 10:f0854784e960 162 char* p = *pp;
andrewboyson 10:f0854784e960 163
andrewboyson 10:f0854784e960 164 *p++ = code;
andrewboyson 10:f0854784e960 165 *p++ = 4;
andrewboyson 10:f0854784e960 166 *p++ = (value & 0x000000FF) >> 0;
andrewboyson 10:f0854784e960 167 *p++ = (value & 0x0000FF00) >> 8;
andrewboyson 10:f0854784e960 168 *p++ = (value & 0x00FF0000) >> 16;
andrewboyson 10:f0854784e960 169 *p++ = (value & 0xFF000000) >> 24;
andrewboyson 10:f0854784e960 170
andrewboyson 10:f0854784e960 171 *pp += 6;
andrewboyson 10:f0854784e960 172 }
andrewboyson 10:f0854784e960 173 int sendRequest(void* pPacket, uint8_t code, uint32_t srvIp, uint32_t reqIp)
andrewboyson 10:f0854784e960 174 {
andrewboyson 10:f0854784e960 175
andrewboyson 10:f0854784e960 176 switch (code)
andrewboyson 10:f0854784e960 177 {
andrewboyson 10:f0854784e960 178 case DHCPDISCOVER:
andrewboyson 37:793b39683406 179 if (DhcpTrace) LogTimeF("DHCP -> discover");
andrewboyson 10:f0854784e960 180 break;
andrewboyson 10:f0854784e960 181 case DHCPREQUEST:
andrewboyson 37:793b39683406 182 if (DhcpTrace) LogTimeF("DHCP -> request");
andrewboyson 10:f0854784e960 183 break;
andrewboyson 10:f0854784e960 184 default:
andrewboyson 10:f0854784e960 185 LogTimeF("DHCP -> unknown message %d", code);
andrewboyson 10:f0854784e960 186 break;
andrewboyson 10:f0854784e960 187 }
andrewboyson 37:793b39683406 188 if (DhcpTrace)
andrewboyson 10:f0854784e960 189 {
andrewboyson 47:73af5c0b0dc2 190 Log(" server=" ); Ip4AddressLog(srvIp);
andrewboyson 47:73af5c0b0dc2 191 Log(" request="); Ip4AddressLog(reqIp);
andrewboyson 47:73af5c0b0dc2 192 Log(" local=" ); Ip4AddressLog(DhcpLocalIp);
andrewboyson 47:73af5c0b0dc2 193 Log("\r\n");
andrewboyson 10:f0854784e960 194 }
andrewboyson 10:f0854784e960 195
andrewboyson 10:f0854784e960 196 bool broadcast = DhcpLocalIp == 0;
andrewboyson 10:f0854784e960 197 uint16_t flags = 0;
andrewboyson 10:f0854784e960 198 if (broadcast) flags |= 0x0080; //0x8000 on the net == 0x0080 in little endian
andrewboyson 10:f0854784e960 199 struct header* pHeader = (header*)pPacket;
andrewboyson 10:f0854784e960 200 pHeader->op = REQUEST;
andrewboyson 10:f0854784e960 201 pHeader->htype = ETHERNET;
andrewboyson 10:f0854784e960 202 pHeader->hlen = 6;
andrewboyson 10:f0854784e960 203 pHeader->hops = 0;
andrewboyson 10:f0854784e960 204 pHeader->xid = ID; //Randomly chosed transaction id used to associate messages to responses
andrewboyson 10:f0854784e960 205 pHeader->secs = 0; //Seconds since started to boot
andrewboyson 10:f0854784e960 206 pHeader->flags = flags; //Broadcast (1) Unicast (0)
andrewboyson 10:f0854784e960 207 pHeader->ciaddr = DhcpLocalIp; //'Client' address set by client or 0 if don't know address
andrewboyson 10:f0854784e960 208 pHeader->yiaddr = 0; //'Your' address returned by server
andrewboyson 10:f0854784e960 209 pHeader->siaddr = srvIp; //'Server' address to use if required
andrewboyson 10:f0854784e960 210 pHeader->giaddr = 0; //'Gateway' address
andrewboyson 13:9cd54f7db57a 211 memcpy(pHeader->chaddr, MacLocal, 6); //'Client hardware' address. 6 bytes for ethernet
andrewboyson 10:f0854784e960 212 memset(pHeader->legacy, 0, 192); //BootP legacy fill with zeros
andrewboyson 10:f0854784e960 213 pHeader->cookie = NetToHost32(COOKIE); //Magic cookie
andrewboyson 10:f0854784e960 214
andrewboyson 10:f0854784e960 215 char* pOptions = (char*)pPacket + HEADER_LENGTH;
andrewboyson 10:f0854784e960 216 char* p = pOptions;
andrewboyson 10:f0854784e960 217 *p++ = 53; //Message code
andrewboyson 10:f0854784e960 218 *p++ = 1;
andrewboyson 10:f0854784e960 219 *p++ = code;
andrewboyson 10:f0854784e960 220
andrewboyson 10:f0854784e960 221 writeIp(50, reqIp, &p); //Requested IP
andrewboyson 10:f0854784e960 222 writeIp(54, srvIp, &p); //Server ip
andrewboyson 10:f0854784e960 223
andrewboyson 10:f0854784e960 224 *p++ = 255; //End of options
andrewboyson 10:f0854784e960 225
andrewboyson 10:f0854784e960 226 delayTime = 0;
andrewboyson 10:f0854784e960 227 return HEADER_LENGTH + p - pOptions;
andrewboyson 10:f0854784e960 228 }
andrewboyson 59:e0e556c8bd46 229 int DhcpHandleResponse(void (*traceback)(void), int sizeRx, void* pPacketRx, int* pSizeTx, void* pPacketTx)
andrewboyson 10:f0854784e960 230 {
andrewboyson 59:e0e556c8bd46 231 struct header* pHeaderRx = (header*)pPacketRx;
andrewboyson 10:f0854784e960 232
andrewboyson 59:e0e556c8bd46 233 uint8_t op = pHeaderRx->op;
andrewboyson 59:e0e556c8bd46 234 uint8_t htype = pHeaderRx->htype;
andrewboyson 59:e0e556c8bd46 235 uint8_t hlen = pHeaderRx->hlen;
andrewboyson 10:f0854784e960 236
andrewboyson 59:e0e556c8bd46 237 uint32_t xid = pHeaderRx->xid; //Randomly chosen transaction id used to associate messages to responses
andrewboyson 10:f0854784e960 238
andrewboyson 59:e0e556c8bd46 239 uint16_t secs = NetToHost16(pHeaderRx->secs);
andrewboyson 59:e0e556c8bd46 240 uint16_t flags = NetToHost16(pHeaderRx->flags);
andrewboyson 10:f0854784e960 241
andrewboyson 59:e0e556c8bd46 242 uint32_t yiaddr = pHeaderRx->yiaddr;
andrewboyson 59:e0e556c8bd46 243 uint32_t siaddr = pHeaderRx->siaddr;
andrewboyson 59:e0e556c8bd46 244 uint32_t cookie = NetToHost32(pHeaderRx->cookie);
andrewboyson 10:f0854784e960 245
andrewboyson 59:e0e556c8bd46 246 if (op != REPLY) return DO_NOTHING;
andrewboyson 59:e0e556c8bd46 247 if (htype != ETHERNET) return DO_NOTHING;
andrewboyson 59:e0e556c8bd46 248 if (hlen != 6) return DO_NOTHING;
andrewboyson 59:e0e556c8bd46 249 if (memcmp(pHeaderRx->chaddr, MacLocal, 6)) return DO_NOTHING;
andrewboyson 59:e0e556c8bd46 250 if (xid != ID) return DO_NOTHING;
andrewboyson 59:e0e556c8bd46 251 if (cookie != COOKIE) return DO_NOTHING;
andrewboyson 10:f0854784e960 252
andrewboyson 59:e0e556c8bd46 253 char* pOptions = (char*)pPacketRx + HEADER_LENGTH;
andrewboyson 59:e0e556c8bd46 254 readOptions(sizeRx - HEADER_LENGTH, pOptions);
andrewboyson 10:f0854784e960 255
andrewboyson 10:f0854784e960 256 switch (dhcpMessageType)
andrewboyson 10:f0854784e960 257 {
andrewboyson 10:f0854784e960 258 case DHCPOFFER:
andrewboyson 47:73af5c0b0dc2 259 if (DhcpTrace) { LogTime("DHCP <- offer ip "); Ip4AddressLog(yiaddr); Log("\r\n"); }
andrewboyson 59:e0e556c8bd46 260 *pSizeTx = sendRequest(pPacketTx, DHCPREQUEST, siaddr, yiaddr);
andrewboyson 10:f0854784e960 261 return BROADCAST;
andrewboyson 10:f0854784e960 262 case DHCPACK:
andrewboyson 47:73af5c0b0dc2 263 if (DhcpTrace) { LogTime("DHCP <- ack ip "); Ip4AddressLog(yiaddr); Log("\r\n"); }
andrewboyson 10:f0854784e960 264 DhcpLocalIp = yiaddr;
andrewboyson 29:39277bf2003d 265 DhcpElapsedTime = 0;
andrewboyson 10:f0854784e960 266 break;
andrewboyson 10:f0854784e960 267 case DHCPNAK:
andrewboyson 47:73af5c0b0dc2 268 if (DhcpTrace) { LogTime("DHCP <- nack ip "); Ip4AddressLog(yiaddr); Log("\r\n"); }
andrewboyson 10:f0854784e960 269 break;
andrewboyson 10:f0854784e960 270 default:
andrewboyson 10:f0854784e960 271 LogTimeF("DHCP <- unknown message %d\r\n", dhcpMessageType);
andrewboyson 10:f0854784e960 272 break;
andrewboyson 10:f0854784e960 273 }
andrewboyson 10:f0854784e960 274 return DO_NOTHING;
andrewboyson 10:f0854784e960 275 }
andrewboyson 10:f0854784e960 276
andrewboyson 10:f0854784e960 277 int DhcpPollForRequestToSend(void* pPacket, int* pSize)
andrewboyson 10:f0854784e960 278 {
andrewboyson 10:f0854784e960 279 if (delayTime < REPEAT_DELAY_TIME) return DO_NOTHING; //Don't retry within the delay time
andrewboyson 10:f0854784e960 280
andrewboyson 29:39277bf2003d 281 if (DhcpLocalIp && DhcpElapsedTime < (DhcpLeaseTime >> 1)) return 0; //Do nothing if have address and within T1
andrewboyson 10:f0854784e960 282
andrewboyson 10:f0854784e960 283 *pSize = 0;
andrewboyson 37:793b39683406 284 int dest = DO_NOTHING;
andrewboyson 29:39277bf2003d 285 if (DhcpLocalIp && DhcpElapsedTime < DhcpLeaseTime)
andrewboyson 10:f0854784e960 286 {
andrewboyson 10:f0854784e960 287 *pSize = sendRequest(pPacket, DHCPREQUEST, DhcpServer, DhcpLocalIp); //if within T2 then send request to the server - not broadcast
andrewboyson 37:793b39683406 288 dest = UNICAST_DHCP;
andrewboyson 10:f0854784e960 289 }
andrewboyson 10:f0854784e960 290 else
andrewboyson 10:f0854784e960 291 {
andrewboyson 37:793b39683406 292 if (DhcpTrace) LogTimeF("DHCP lease has expired\r\n");
andrewboyson 10:f0854784e960 293 DhcpLocalIp = 0;
andrewboyson 10:f0854784e960 294 DhcpServer = 0;
andrewboyson 10:f0854784e960 295 *pSize = sendRequest(pPacket, DHCPDISCOVER, 0, 0); //If outside T2 then start from scratch to do a full DHCP
andrewboyson 37:793b39683406 296 dest = BROADCAST;
andrewboyson 10:f0854784e960 297 }
andrewboyson 37:793b39683406 298 return ActionMakeFromDestAndTrace(dest, DhcpTrace);
andrewboyson 10:f0854784e960 299 }