dsfx/pkg/network/conn.go

93 lines
2.4 KiB
Go

package network
import (
"crypto/ed25519"
"net"
"time"
"koti.casa/numenor-labs/dsfx/pkg/crypto/encryption"
"koti.casa/numenor-labs/dsfx/pkg/frame"
)
// Conn is a wrapper around net.TCPConn that encrypts and decrypts data as it is
// read and written. Conn is a valid implementation of net.Conn.
type Conn struct {
conn *net.TCPConn
sessionKey []byte
localIdentity ed25519.PublicKey
remoteIdentity ed25519.PublicKey
}
// NewConn creates a new Conn.
func NewConn(conn *net.TCPConn, sessionKey []byte, localIdentity, remoteIdentity ed25519.PublicKey) *Conn {
return &Conn{conn, sessionKey, localIdentity, remoteIdentity}
}
// Read implements io.Reader.
// Please note that number of bytes returned is the length of the decrypted data.
// The ciphertext that is actually transferred over the network is larger, so you
// should not rely on this number as an indication of network metrics.
func (c *Conn) Read(b []byte) (int, error) {
f := frame.New(nil)
_, err := f.ReadFrom(c.conn)
if err != nil {
return 0, err
}
plaintext, err := encryption.Decrypt(c.sessionKey, f.Contents())
if err != nil {
return 0, err
}
copy(b, plaintext)
return len(plaintext), nil
}
// Write implements io.Writer.
func (c *Conn) Write(b []byte) (int, error) {
ciphertext, err := encryption.Encrypt(c.sessionKey, b)
if err != nil {
return 0, err
}
_, err = frame.New(ciphertext).WriteTo(c.conn)
if err != nil {
return 0, err
}
return len(b), nil
}
// Close implements io.Closer.
func (c *Conn) Close() error {
// x-security: clear key to mitigate memory attacks
c.sessionKey = nil
c.localIdentity = nil
c.remoteIdentity = nil
return c.conn.Close()
}
// LocalAddr implements net.Conn.
func (c *Conn) LocalAddr() net.Addr {
raddr := c.conn.RemoteAddr().(*net.TCPAddr)
return NewAddr(raddr.IP, raddr.Port, c.localIdentity)
}
// RemoteAddr implements net.Conn.
func (c *Conn) RemoteAddr() net.Addr {
raddr := c.conn.RemoteAddr().(*net.TCPAddr)
return NewAddr(raddr.IP, raddr.Port, c.remoteIdentity)
}
// SetDeadline implements net.Conn.
func (c *Conn) SetDeadline(t time.Time) error {
return c.conn.SetDeadline(t)
}
// SetReadDeadline implements net.Conn.
func (c *Conn) SetReadDeadline(t time.Time) error {
return c.conn.SetReadDeadline(t)
}
// SetWriteDeadline implements net.Conn.
func (c *Conn) SetWriteDeadline(t time.Time) error {
return c.conn.SetWriteDeadline(t)
}