349 lines
10 KiB
Go
349 lines
10 KiB
Go
package common
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/*
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I2P LeaseSet
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https://geti2p.net/spec/common-structures#leaseset
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Accurate for version 0.9.24
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+----+----+----+----+----+----+----+----+
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| destination |
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+ +
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~ ~
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~ ~
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+----+----+----+----+----+----+----+----+
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| encryption_key |
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+ +
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~ ~
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~ ~
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+----+----+----+----+----+----+----+----+
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| signing_key |
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+ +
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~ ~
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~ ~
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+----+----+----+----+----+----+----+----+
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|num | Lease 0 |
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+----+ +
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~ ~
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~ ~
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+----+----+----+----+----+----+----+----+
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| Lease 1 |
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+ +
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~ ~
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~ ~
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+----+----+----+----+----+----+----+----+
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| Lease ($num-1) |
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+ +
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~ ~
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~ ~
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+----+----+----+----+----+----+----+----+
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| signature |
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+ +
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+ +
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+ +
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+ +
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+----+----+----+----+----+----+----+----+
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destination :: Destination
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length -> >= 387 bytes
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encryption_key :: PublicKey
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length -> 256 bytes
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signing_key :: SigningPublicKey
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length -> 128 bytes or as specified in destination's key certificate
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num :: Integer
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length -> 1 byte
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Number of leases to follow
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value: 0 <= num <= 16
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leases :: [Lease]
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length -> $num*44 bytes
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signature :: Signature
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length -> 40 bytes or as specified in destination's key certificate
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*/
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import (
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"errors"
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log "github.com/sirupsen/logrus"
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"github.com/go-i2p/go-i2p/lib/crypto"
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)
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// Sizes of various structures in an I2P LeaseSet
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const (
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LEASE_SET_PUBKEY_SIZE = 256
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LEASE_SET_SPK_SIZE = 128
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LEASE_SET_SIG_SIZE = 40
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)
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type LeaseSet []byte
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//
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// Read a Destination from the LeaseSet.
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//
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func (lease_set LeaseSet) Destination() (destination Destination, err error) {
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keys_and_cert, _, err := ReadKeysAndCert(lease_set)
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destination = Destination(keys_and_cert)
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return
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}
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//
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// Return the PublicKey in this LeaseSet and any errors ancountered parsing the LeaseSet.
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//
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func (lease_set LeaseSet) PublicKey() (public_key crypto.ElgPublicKey, err error) {
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_, remainder, err := ReadKeysAndCert(lease_set)
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remainder_len := len(remainder)
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if remainder_len < LEASE_SET_PUBKEY_SIZE {
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log.WithFields(log.Fields{
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"at": "(LeaseSet) PublicKey",
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"data_len": remainder_len,
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"required_len": LEASE_SET_PUBKEY_SIZE,
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"reason": "not enough data",
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}).Error("error parsing public key")
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err = errors.New("error parsing public key: not enough data")
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copy(public_key[:], remainder)
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return
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}
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copy(public_key[:], remainder[:LEASE_SET_PUBKEY_SIZE])
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return
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}
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//
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// Return the SigningPublicKey, as specified in the LeaseSet's Destination's Key Certificate if
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// present, or a legacy DSA key.
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//
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func (lease_set LeaseSet) SigningKey() (signing_public_key crypto.SigningPublicKey, err error) {
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destination, err := lease_set.Destination()
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if err != nil {
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return
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}
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offset := len(destination) + LEASE_SET_PUBKEY_SIZE
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cert, err := destination.Certificate()
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if err != nil {
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return
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}
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cert_len, err := cert.Length()
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if err != nil {
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return
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}
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lease_set_len := len(lease_set)
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if lease_set_len < offset+LEASE_SET_SPK_SIZE {
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log.WithFields(log.Fields{
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"at": "(LeaseSet) SigningKey",
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"data_len": lease_set_len,
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"required_len": offset + LEASE_SET_SPK_SIZE,
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"reason": "not enough data",
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}).Error("error parsing signing public key")
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err = errors.New("error parsing signing public key: not enough data")
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return
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}
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if cert_len == 0 {
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// No Certificate is present, return the LEASE_SET_SPK_SIZE byte
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// SigningPublicKey space as legacy DSA SHA1 SigningPublicKey.
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var dsa_pk crypto.DSAPublicKey
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copy(dsa_pk[:], lease_set[offset:offset+LEASE_SET_SPK_SIZE])
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signing_public_key = dsa_pk
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} else {
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// A Certificate is present in this LeaseSet's Destination
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cert_type, _ := cert.Type()
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if cert_type == CERT_KEY {
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// This LeaseSet's Destination's Certificate is a Key Certificate,
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// create the signing publickey key using any data that might be
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// contained in the key certificate.
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signing_public_key, err = KeyCertificate(cert).ConstructSigningPublicKey(
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lease_set[offset : offset+LEASE_SET_SPK_SIZE],
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)
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} else {
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// No Certificate is present, return the LEASE_SET_SPK_SIZE byte
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// SigningPublicKey space as legacy DSA SHA1 SigningPublicKey.
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var dsa_pk crypto.DSAPublicKey
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copy(dsa_pk[:], lease_set[offset:offset+LEASE_SET_SPK_SIZE])
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signing_public_key = dsa_pk
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}
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}
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return
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}
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//
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// Return the number of Leases specified by the LeaseCount value in this LeaseSet.
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//
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func (lease_set LeaseSet) LeaseCount() (count int, err error) {
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_, remainder, err := ReadKeysAndCert(lease_set)
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if err != nil {
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return
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}
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remainder_len := len(remainder)
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if remainder_len < LEASE_SET_PUBKEY_SIZE+LEASE_SET_SPK_SIZE+1 {
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log.WithFields(log.Fields{
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"at": "(LeaseSet) LeaseCount",
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"data_len": remainder_len,
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"required_len": LEASE_SET_PUBKEY_SIZE + LEASE_SET_SPK_SIZE + 1,
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"reason": "not enough data",
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}).Error("error parsing lease count")
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err = errors.New("error parsing lease count: not enough data")
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return
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}
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count = Integer([]byte{remainder[LEASE_SET_PUBKEY_SIZE+LEASE_SET_SPK_SIZE]})
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if count > 16 {
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log.WithFields(log.Fields{
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"at": "(LeaseSet) LeaseCount",
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"lease_count": count,
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"reason": "more than 16 leases",
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}).Warn("invalid lease set")
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err = errors.New("invalid lease set: more than 16 leases")
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}
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return
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}
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//
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// Read the Leases in this LeaseSet, returning a partial set if there is insufficient data.
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//
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func (lease_set LeaseSet) Leases() (leases []Lease, err error) {
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destination, err := lease_set.Destination()
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if err != nil {
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return
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}
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offset := len(destination) + LEASE_SET_PUBKEY_SIZE + LEASE_SET_SPK_SIZE + 1
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count, err := lease_set.LeaseCount()
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if err != nil {
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return
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}
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for i := 0; i < count; i++ {
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start := offset + (i * LEASE_SIZE)
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end := start + LEASE_SIZE
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lease_set_len := len(lease_set)
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if lease_set_len < end {
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log.WithFields(log.Fields{
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"at": "(LeaseSet) Leases",
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"data_len": lease_set_len,
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"required_len": end,
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"reason": "some leases missing",
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}).Error("error parsnig lease set")
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err = errors.New("error parsing lease set: some leases missing")
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return
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}
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var lease Lease
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copy(lease[:], lease_set[start:end])
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leases = append(leases, lease)
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}
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return
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}
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//
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// Return the Signature data for the LeaseSet, as specified in the Destination's
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// Key Certificate if present or the 40 bytes following the Leases.
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//
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func (lease_set LeaseSet) Signature() (signature Signature, err error) {
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destination, err := lease_set.Destination()
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if err != nil {
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return
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}
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lease_count, err := lease_set.LeaseCount()
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if err != nil {
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return
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}
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start := len(destination) +
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LEASE_SET_PUBKEY_SIZE +
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LEASE_SET_SPK_SIZE +
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1 +
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(LEASE_SIZE * lease_count)
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cert, err := destination.Certificate()
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if err != nil {
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return
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}
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cert_type, _ := cert.Type()
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var end int
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if cert_type == CERT_KEY {
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end = start + KeyCertificate(cert).SignatureSize()
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} else {
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end = start + LEASE_SET_SIG_SIZE
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}
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lease_set_len := len(lease_set)
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if lease_set_len < end {
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log.WithFields(log.Fields{
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"at": "(LeaseSet) Signature",
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"data_len": lease_set_len,
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"required_len": end,
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"reason": "not enough data",
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}).Error("error parsing signatre")
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err = errors.New("error parsing signature: not enough data")
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return
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}
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signature = []byte(lease_set[start:end])
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return
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}
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//
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//
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//
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func (lease_set LeaseSet) Verify() error {
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//data_end := len(destination) +
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// LEASE_SET_PUBKEY_SIZE +
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// LEASE_SET_SPK_SIZE +
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// 1 +
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// (44 * lease_set.LeaseCount())
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//data := lease_set[:data_end]
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//spk, _ := lease_set.
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// Destination().
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// SigningPublicKey()
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//verifier, err := spk.NewVerifier()
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//if err != nil {
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// return err
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//}
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return nil // verifier.Verify(data, lease_set.Signature())
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}
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//
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// Return the oldest date from all the Leases in the LeaseSet.
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//
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func (lease_set LeaseSet) NewestExpiration() (oldest Date, err error) {
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leases, err := lease_set.Leases()
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if err != nil {
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return
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}
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oldest = Date{0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
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for _, lease := range leases {
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date := lease.Date()
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if date.Time().After(oldest.Time()) {
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oldest = date
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}
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}
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return
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}
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//
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// Return the oldest date from all the Leases in the LeaseSet.
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//
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func (lease_set LeaseSet) OldestExpiration() (earliest Date, err error) {
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leases, err := lease_set.Leases()
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if err != nil {
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return
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}
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earliest = Date{0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}
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for _, lease := range leases {
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date := lease.Date()
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if date.Time().Before(earliest.Time()) {
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earliest = date
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}
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}
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return
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}
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