rs.c

00001 #include <stdint.h>
00002 #include <stdbool.h>
00003 
00004 #include "log.h"
00005 #include "net.h"
00006 #include "ndp.h"
00007 #include "ip6.h"
00008 #include "ip6addr.h"
00009 #include "slaac.h"
00010 #include "action.h"
00011 #include "mac.h"
00012 #include "mstimer.h"
00013 
00014 bool RsTrace = false;
00015 
00016 bool RsSendSolicitation = false;
00017 
00018 #define MAX_REPEAT_DELAY_TIME_MS 60000
00019 #define MIN_REPEAT_DELAY_TIME_MS   800
00020 static uint32_t repeatDelayMsTimer = (uint32_t)-MIN_REPEAT_DELAY_TIME_MS; //Initial value ensures no delay at startup
00021 static uint32_t delayMs            =            MIN_REPEAT_DELAY_TIME_MS; //Doubles on failure up to max; reset to min whenever an IP address request has been acknowledged
00022 
00023 static void hdrSetReserved(char* pPacket, uint32_t value) { NetInvert32(pPacket + 0, &value); }
00024 static const int HEADER_LENGTH = 4;
00025 
00026 static void logHeader(char* pPacket, int size)
00027 {
00028     char* pData = pPacket + HEADER_LENGTH;
00029     int dataLength = size - HEADER_LENGTH;
00030     
00031     if (NetTraceVerbose)
00032     {
00033         Log("RS header\r\n");
00034         LogF("  Size        %d\r\n", size);
00035         NdpLogOptionsVerbose(pData, dataLength);
00036     }
00037     else
00038     {
00039         Log("RS    header");
00040         NdpLogOptionsQuiet(pData, dataLength);
00041         Log("\r\n");
00042     }
00043 }
00044 int RsGetWaitingSolicitation(char* pPacket, int* pSize, uint8_t* pType, uint8_t* pCode)
00045 {
00046     //Check if time to update
00047     if (NdpIsFresh())
00048     {
00049         delayMs = MIN_REPEAT_DELAY_TIME_MS; //Set the delay time back to minimum
00050         return DO_NOTHING;
00051     }
00052 
00053     //Limit retries with a backoff delay
00054     if (!MsTimerRelative(repeatDelayMsTimer, delayMs)) return DO_NOTHING;          //Don't retry within the delay time
00055     delayMs <<= 1;                                                                 //Backoff (double) the delay time after each attempt
00056     if (delayMs > MAX_REPEAT_DELAY_TIME_MS) delayMs = MAX_REPEAT_DELAY_TIME_MS;    //Don't go beyond a maximum
00057     repeatDelayMsTimer = MsTimerCount;                                             //Start the delay timer
00058 
00059     //Send the renewal request
00060     *pType = 133; //Router solicitation
00061     *pCode = 0;
00062 
00063     hdrSetReserved(pPacket, 0);
00064     
00065     char* pData = (char*)pPacket + HEADER_LENGTH;
00066     char* p = pData;
00067     p += NdpAddOptionSourceMac(p, MacLocal);
00068     
00069     *pSize = HEADER_LENGTH + p - pData;
00070     
00071     if (RsTrace)
00072     {
00073         if (NetTraceNewLine) Log("\r\n");
00074         LogTime("NDP send router solicit\r\n");
00075         logHeader(pPacket, *pSize);
00076     }
00077     
00078     return ActionMakeFromDestAndTrace(MULTICAST_ROUTER, RsTrace && NetTraceStack);
00079     
00080 }