Each node on the network is supposed to have a unique cryptographic
identity. Typically, this identity is generated randomly at startup
and stored for later reuse in the (poorly named) file `wallet.db`.
If the file is copied, it is possible for two nodes to share the
same node identity. This is generally not desirable and existing
servers will detect and reject connections to other servers that
have the same key.
This commit achives three things:
1. It improves the detection code to pinpoint instances where two
distinct servers with the same key connect with each other. In
that case, servers will log an appropriate error and shut down
pending intervention by the server's operator.
2. It makes it possible for server administrators to securely and
easily generate new cryptographic identities for servers using
the new `--newnodeid` command line arguments. When a server is
started using this command, it will generate and save a random
secure identity.
3. It makes it possible to configure the identity using a command
line option, which makes it possible to derive it from data or
parameters associated with the container or hardware where the
instance is running by passing the `--nodeid` option, followed
by a single argument identifying the infomation from which the
node's identity is derived. For example, the following command
will result in nodes with different hostnames having different
node identities: `rippled --nodeid $HOSTNAME`
The last option is particularly useful for automated cloud-based
deployments that minimize the need for storing state and provide
unique deployment identifiers.
**Important note for server operators:**
Depending on variables outside of the the control of this code,
such as operating system version or configuration, permissions,
and more, it may be possible for other users or programs to be
able to access the command line arguments of other processes
on the system.
If you are operating in a shared environment, you should avoid
using this option, preferring instead to use the `[node_seed]`
option in the configuration file, and use permissions to limit
exposure of the node seed.
A user who gains access to the value used to derive the node's
unique identity could impersonate that node.
The commit also updates the minimum supported server protocol
version to `XRPL/2.1`, which has been supported since version
1.5.0 and eliminates support for `XPRL/2.0`.
This commit restructures the HTTP based protocol negotiation that `rippled`
executes and introduces support for negotiation of compression for peer
links which, if implemented, should result in significant bandwidth savings
for some server roles.
This commit also introduces the new `[network_id]` configuration option
that administrators can use to specify which network the server is part of
and intends to join. This makes it possible for servers from different
networks to drop the link early.
The changeset also improves the log messages generated when negotiation
of a peer link upgrade fails. In the past, no useful information would
be logged, making it more difficult for admins to troubleshoot errors.
This commit also fixes RIPD-237 and RIPD-451
