public bool AddVault(Vault v)
{
// track stats
TotalJoins++;
// get prefix for vault
var prefix = GetPrefixForXorname(v.Name);
Section section = default(Section);
// get the section for this prefix
if (!Sections.ContainsKey(prefix.Key))
{
var blankPrefix = new Prefix();
var netEvt = Section.NewSection(blankPrefix, new List <Vault>());
if (netEvt != null)
{
foreach (var s in netEvt.NewSections)
{
section = s;
Sections[section.Prefix.Key] = section;
}
}
}
else
{
section = Sections[prefix.Key];
}
// add the vault to the section
var(ne, disallowed) = section.AddVault(v);
// if there was a split
if (ne != null && ne.NewSections.Count > 0)
{
TotalSplits++;
// add new sections
foreach (var s in ne.NewSections)
{
Sections[s.Prefix.Key] = s;
}
// remove old section
Sections.Remove(section.Prefix.Key);
}
// relocate vault if there is one to relocate
if (ne != null && ne.VaultToRelocate != null)
{
RelocateVault(ne);
}
return(disallowed);
}
// @mav:
// There should never be a prefix longer than the vault name length (vault name length is constant at 256 bits).
// This would mean there’s approx 2^256 sections in the network which is pretty massive.
public void RenameWithPrefix(Prefix p)
{
if (p.Bits.Count > Name.Bits.Count)
{
Console.WriteLine("Warning: prefix bit count longer than name bit count!");
}
var newBits = Name.Bits.Count >= p.Bits.Count ?
new BitArray(Name.Bits) : new BitArray(p.Bits);
for (int i = 0; i < p.Bits.Count; i++)
{
newBits.Set(i, p.Bits[i]);
}
Name = new XorName(newBits);
}
public Prefix ExtendLeft()
{
var newBits = new BitArray(Bits.Count + 1);
foreach (int i in Enumerable.Range(0, Bits.Count))
{
newBits[i] = Bits[i];
}
var left = new Prefix
{
Bits = newBits
};
left.SetKey();
return(left);
}
public Prefix Sibling()
{
var s = new Prefix
{
Bits = Bits
};
if (s.Bits.Count == 0)
{
Console.WriteLine("Warning: There should be no calling of Sibling on empty prefix!");
}
else
{
s.Bits[s.Bits.Count - 1] = !s.Bits[s.Bits.Count - 1];
}
s.SetKey();
return(s);
}
public Prefix ExtendRight()
{
var newBits = new BitArray(Bits.Count + 1);
foreach (int i in Enumerable.Range(0, Bits.Count))
{
newBits[i] = Bits[i];
}
newBits[newBits.Count - 1] = true;
var right = new Prefix
{
Bits = newBits
};
right.SetKey();
return(right);
}
internal Prefix Parent()
{
if (Bits.Count == 0)
{
Console.WriteLine("Warning: There should be no calling of Parent on empty prefix!");
}
var newBits = new BitArray(Math.Max(0, Bits.Count - 1));
foreach (int i in Enumerable.Range(0, newBits.Count))
{
newBits[i] = Bits[i];
}
var a = new Prefix
{
Bits = newBits
};
a.SetKey();
return(a);
}
// Returns a slice of sections since as vaults age they may cascade into
// multiple sections.
public static NetworkEvent NewSection(Prefix prefix, List <Vault> vaults)
{
var section = new Section
{
Prefix = prefix,
};
// add each existing vault to new section
foreach (var vault in vaults)
{
vault.SetPrefix(section.Prefix);
section.Vaults.Add(vault);
}
// split into two sections if needed.
// there is no vault relocation here.
if (section.ShouldSplit())
{
return(section.Split());
}
// return the section as a network event.
// there is a vault relocation here.
var netEvt = new NetworkEvent
{
NewSections = new List <Section> {
section
}
};
var toRelocate = section.VaultForRelocation(netEvt);
if (toRelocate != null)
{
netEvt.VaultToRelocate = toRelocate;
}
return(netEvt);
}
Prefix GetPrefixForXorname(XorName x)
{
var prefix = new Prefix();
while (!Sections.ContainsKey(prefix.Key) && prefix.Bits.Count < x.Bits.Count)
{
// get the next bit of the xorname prefix
// extend the prefix depending on the bit of the xorname
if (!x.Bits[prefix.Bits.Count])
{
prefix = prefix.ExtendLeft();
}
else
{
prefix = prefix.ExtendRight();
}
}
if (!Sections.ContainsKey(prefix.Key) && HasMoreThanOneVault())
{
Debug.WriteLine("Warning: No prefix for xorname");
return(new Prefix());
}
return(prefix);
}
int AdultCountForExtendedPrefix(Prefix p)
{
return(Vaults.Count(v => v.IsAdult() && p.Matches(v.Name)));
}
int RightAdultCount()
{
var rightPrefix = Prefix.ExtendRight();
return(AdultCountForExtendedPrefix(rightPrefix));
}
int LeftAdultCount()
{
var leftPrefix = Prefix.ExtendLeft();
return(AdultCountForExtendedPrefix(leftPrefix));
}
int VaultCountForExtendedPrefix(Prefix p)
{
return(Vaults.Count(v => p.Matches(v.Name)));
}
public void SetPrefix(Prefix p)
{
Prefix = p;
}
void RelocateVault(NetworkEvent ne)
{
// track stats for relocations
TotalRelocations++;
// find the neighbour with shortest prefix or fewest vaults
// default to the existing section, useful for zero-length prefix
var smallestNeighbour = Sections[ne.VaultToRelocate.Prefix.Key];
var minNeighbourPrefix = UInt32.MaxValue;
var minNeighbourVaults = UInt32.MaxValue;
// get all neighbours
for (int i = 0; i < ne.VaultToRelocate.Prefix.Bits.Count; i++)
{
// clone the prefix but flip the ith bit of the prefix
var neighbourPrefix = new Prefix();
for (int j = 0; j < ne.VaultToRelocate.Prefix.Bits.Count; j++)
{
var isZero = !(bool)ne.VaultToRelocate.Prefix.Bits[j];
if (j == i)
{
isZero = !isZero;
}
if (isZero)
{
neighbourPrefix = neighbourPrefix.ExtendLeft();
}
else
{
neighbourPrefix = neighbourPrefix.ExtendRight();
}
}
// get neighbouring prefixes from the network for this prefix
// and repeat until we arrive at the 'best' neighbour prefix
var prevNeighbourPrefix = new Prefix();
while (!neighbourPrefix.Equals(prevNeighbourPrefix))
{
// track previous neighbour prefix
prevNeighbourPrefix = neighbourPrefix;
// get potential new neighbour prefixes
var neighbourPrefixes = GetMatchingPrefixes(neighbourPrefix);
// check if these neighbours contain the 'best' neighbour
// prioritise sections with shorter prefixes and having less nodes to balance the network
foreach (var p in neighbourPrefixes)
{
var s = Sections[p.Key];
if (p.Bits.Count < minNeighbourPrefix)
{
// prefer shorter prefixes
neighbourPrefix = p;
minNeighbourPrefix = (uint)p.Bits.Count;
smallestNeighbour = s;
}
else if (p.Bits.Count == minNeighbourPrefix)
{
// prefer less vaults if prefix length is same
if (s.Vaults.Count < minNeighbourVaults)
{
neighbourPrefix = p;
minNeighbourVaults = (uint)s.Vaults.Count;
smallestNeighbour = s;
}
else if (s.Vaults.Count == minNeighbourVaults)
{
// TODO tiebreaker for equal sized neighbours
// see https://forum.safedev.org/t/data-chains-deeper-dive/1209
// If all neighbours have the same number of peers we relocate
// to the section closest to the H above (that is not us)
}
}
}
}
}
// track neighbourhood hops by comparing how many bits differ
// between the new and the old prefix.
var neighbourhoodHops = 0;
var prefixLength = smallestNeighbour.Prefix.Key.Length;
if (ne.VaultToRelocate.Prefix.Key.Length < prefixLength)
{
prefixLength = ne.VaultToRelocate.Prefix.Key.Length;
}
for (int i = 0; i < prefixLength; i++)
{
var newBit = smallestNeighbour.Prefix.Key[i];
var oldBit = ne.VaultToRelocate.Prefix.Key[i];
if (newBit != oldBit)
{
neighbourhoodHops++;
}
}
NeighbourhoodHops.Add(neighbourhoodHops);
// remove vault from current section (includes merge if needed)
RemoveVault(ne.VaultToRelocate);
// adjust vault name to match the neighbour section prefix
ne.VaultToRelocate.RenameWithPrefix(smallestNeighbour.Prefix);
// age the relocated vault
ne.VaultToRelocate.IncrementAge();
// relocate the vault to the smallest neighbour (includes split if needed)
var disallowed = AddVault(ne.VaultToRelocate);
if (disallowed)
{
Debug.WriteLine("Warning: disallowed relocated vault");
}
}
public bool Equals(Prefix q)
{
return(Key == q.Key);
}