Ensure ASSETCHAINS_MINOPRETURNFEE modifies chain magic and document why

doc/DEVELOPING.md

@@ -89,6 +89,41 @@ After successfully compiling Hush, you can generate a debian package of these bi
 This command will not work on Mac OS X. Currently you cannot generate a Debian package
 from operating systems other than Linux. Oh well.
 
+## Adding new CLI options that change consensus rules
+
+If you are adding a new CLI option that changes consensus rules such as
+`-ac_foo` then make sure to also modify the the `extraptr` variable in
+`src/hush_utils.h` with the value of the `ASSETCHAINS_FOO` variable.  Our
+convention is that if a CLI option affects consensus, it MUST begin with `-ac_`
+and if it does not affect consensus (such as -datadir) then it MUST NOT begin
+with `-ac_`. Originally the `ac` meant "asset chain" but now it means "affects
+consensus" or "arrakis chain", take your pick.
+
+The reason for this is the `extraptr` variable is used to deterministically
+generate the "chain magic" `ASSETCHAINS_MAGIC` as well as the default p2p and
+rpc ports for a HAC. This means that if two HACs have *exactly* the same
+consensus options except for `-ac_foo` (even if they have the same `-ac_name`)
+then they will still get different chain magic values and p2p and rpc ports.
+This is a way of preventing HACs with different consensus rules from trying to
+talk with each other when they should not. For instance, if you make a HAC with
+`-ac_name=MYCOIN` on one machine with one set of consensus rules and then
+another HAC with the same name on a different machine but with different
+consensus rules, the chain magic being different (as well as the default p2p
+port) are ways to prevent them from communicating. This is good because these
+two HACs will eventually chain fork due to their different consensus rules and
+ban each other, wasting time, bandwidth and sanity.
+
+An example of doing this can be seen in the commit
+https://git.hush.is/hush/hush3/commit/d39503c13b7419620d138050899705ced557eef9
+which added the `-ac_burn` consensus changing option.
+
+The chain magic value is the CRC32 checksum of every non-default consensus
+option the HAC uses.
+
+Also make sure to actually validate the new consensus option! That is probably
+going to happen in `src/main.cpp` . If you don't, a malicious node can just
+modify `src/miner.cpp` to do whatever they want.
+
 ## Updates to this document
 
 If you think something else should be in this guide, please send your suggestions!

src/hush_utils.h

@@ -2169,7 +2169,7 @@ void hush_args(char *argv0)
             }
         }
 
-        if ( ASSETCHAINS_ENDSUBSIDY[0] != 0 || ASSETCHAINS_REWARD[0] != 0 || ASSETCHAINS_HALVING[0] != 0 || ASSETCHAINS_DECAY[0] != 0 || ASSETCHAINS_COMMISSION != 0 || ASSETCHAINS_PUBLIC != 0 || ASSETCHAINS_PRIVATE != 0 || ASSETCHAINS_TXPOW != 0 || ASSETCHAINS_FOUNDERS != 0 || ASSETCHAINS_SCRIPTPUB.size() > 1 || ASSETCHAINS_SELFIMPORT.size() > 0 || ASSETCHAINS_OVERRIDE_PUBKEY33[0] != 0 || ASSETCHAINS_TIMELOCKGTE != _ASSETCHAINS_TIMELOCKOFF|| ASSETCHAINS_ALGO != ASSETCHAINS_EQUIHASH || ASSETCHAINS_LWMAPOS != 0 || ASSETCHAINS_LASTERA > 0 || ASSETCHAINS_BEAMPORT != 0 || ASSETCHAINS_CODAPORT != 0 || ASSETCHAINS_MARMARA != 0 || nonz > 0 || ASSETCHAINS_CCLIB.size() > 0 || ASSETCHAINS_FOUNDERS_REWARD != 0 || ASSETCHAINS_NOTARY_PAY[0] != 0 || ASSETCHAINS_BLOCKTIME != 60 || ASSETCHAINS_CBOPRET != 0 || Mineropret.size() != 0 || (ASSETCHAINS_NK[0] != 0 && ASSETCHAINS_NK[1] != 0) || HUSH_SNAPSHOT_INTERVAL != 0 || ASSETCHAINS_EARLYTXIDCONTRACT != 0 || ASSETCHAINS_CBMATURITY != 0 || ASSETCHAINS_ADAPTIVEPOW != 0 || ASSETCHAINS_BURN != 0)
+        if ( ASSETCHAINS_ENDSUBSIDY[0] != 0 || ASSETCHAINS_REWARD[0] != 0 || ASSETCHAINS_HALVING[0] != 0 || ASSETCHAINS_DECAY[0] != 0 || ASSETCHAINS_COMMISSION != 0 || ASSETCHAINS_PUBLIC != 0 || ASSETCHAINS_PRIVATE != 0 || ASSETCHAINS_TXPOW != 0 || ASSETCHAINS_FOUNDERS != 0 || ASSETCHAINS_SCRIPTPUB.size() > 1 || ASSETCHAINS_SELFIMPORT.size() > 0 || ASSETCHAINS_OVERRIDE_PUBKEY33[0] != 0 || ASSETCHAINS_TIMELOCKGTE != _ASSETCHAINS_TIMELOCKOFF|| ASSETCHAINS_ALGO != ASSETCHAINS_EQUIHASH || ASSETCHAINS_LWMAPOS != 0 || ASSETCHAINS_LASTERA > 0 || ASSETCHAINS_BEAMPORT != 0 || ASSETCHAINS_CODAPORT != 0 || ASSETCHAINS_MARMARA != 0 || nonz > 0 || ASSETCHAINS_CCLIB.size() > 0 || ASSETCHAINS_FOUNDERS_REWARD != 0 || ASSETCHAINS_NOTARY_PAY[0] != 0 || ASSETCHAINS_BLOCKTIME != 60 || ASSETCHAINS_CBOPRET != 0 || Mineropret.size() != 0 || (ASSETCHAINS_NK[0] != 0 && ASSETCHAINS_NK[1] != 0) || HUSH_SNAPSHOT_INTERVAL != 0 || ASSETCHAINS_EARLYTXIDCONTRACT != 0 || ASSETCHAINS_CBMATURITY != 0 || ASSETCHAINS_ADAPTIVEPOW != 0 || ASSETCHAINS_BURN != 0 || ASSETCHAINS_MINOPRETURNFEE)
         {
             if(fDebug)
                 fprintf(stderr,"perc %.4f%% ac_pub=[%02x%02x%02x...] acsize.%d\n",dstr(ASSETCHAINS_COMMISSION)*100,ASSETCHAINS_OVERRIDE_PUBKEY33[0],ASSETCHAINS_OVERRIDE_PUBKEY33[1],ASSETCHAINS_OVERRIDE_PUBKEY33[2],(int32_t)ASSETCHAINS_SCRIPTPUB.size());
@@ -2334,6 +2334,11 @@ void hush_args(char *argv0)
             {
                 extralen += dragon_rwnum(1,&extraptr[extralen],sizeof(ASSETCHAINS_BURN),(void *)&ASSETCHAINS_BURN);
             }
+
+            if ( ASSETCHAINS_MINOPRETURNFEE != 0 )
+            {
+                extralen += dragon_rwnum(1,&extraptr[extralen],sizeof(ASSETCHAINS_MINOPRETURNFEE),(void *)&ASSETCHAINS_MINOPRETURNFEE);
+            }
         }
         
         addn = GetArg("-seednode","");