// ResolveUnspecifiedAddress expands an unspecified ip addresses (/ip4/0.0.0.0, /ip6/::) to
// use the known local interfaces. If ifaceAddr is nil, we request interface addresses
// from the network stack. (this is so you can provide a cached value if resolving many addrs)
func ResolveUnspecifiedAddress(resolve ma.Multiaddr, ifaceAddrs []ma.Multiaddr) ([]ma.Multiaddr, error) {
// split address into its components
split := ma.Split(resolve)
// if first component (ip) is not unspecified, use it as is.
if !manet.IsIPUnspecified(split[0]) {
return []ma.Multiaddr{resolve}, nil
}
out := make([]ma.Multiaddr, 0, len(ifaceAddrs))
for _, ia := range ifaceAddrs {
// must match the first protocol to be resolve.
if ia.Protocols()[0].Code != resolve.Protocols()[0].Code {
continue
}
split[0] = ia
joined := ma.Join(split...)
out = append(out, joined)
log.Debug("adding resolved addr:", resolve, joined, out)
}
if len(out) < 1 {
return nil, fmt.Errorf("failed to resolve: %s", resolve)
}
return out, nil
}
// buildChain returns two parralel slices. One holds a sequence of MatchAppliers,
// which is capable to handle the given Multiaddr with the side constant.
// The second: full Multiaddr split into one or more protocols a piece, which
// is what each MatchApplier.Apply expects as its m argument.
//
// Allowed values for side are match.S_Server and match.S_Client.
func (mr matchreg) buildChain(m ma.Multiaddr, side int) ([]match.MatchApplier, []ma.Multiaddr, error) {
tail := m
chain := []match.MatchApplier{}
split := []ma.Multiaddr{}
for tail.String() != "" {
mch, n, err := mr.matchPrefix(tail, side)
if err != nil {
return nil, nil, err
}
spl := ma.Split(tail)
head := ma.Join(spl[:n]...)
tail = ma.Join(spl[n:]...)
split = append(split, head)
chain = append(chain, mch)
}
return chain, split, nil
}