GNUnet  0.11.x
Functions
gnunet-service-core_kx.h File Reference

code for managing the key exchange (SET_KEY, PING, PONG) with other peers More...

#include "gnunet_util_lib.h"
#include "gnunet_transport_service.h"
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Functions

void GSC_KX_encrypt_and_transmit (struct GSC_KeyExchangeInfo *kx, const void *payload, size_t payload_size)
 Encrypt and transmit a message with the given payload. More...
 
int GSC_KX_init (struct GNUNET_CRYPTO_EddsaPrivateKey *pk)
 Initialize KX subsystem. More...
 
void GSC_KX_done (void)
 Shutdown KX subsystem. More...
 
int GSC_NEIGHBOURS_check_excess_bandwidth (const struct GSC_KeyExchangeInfo *target)
 Check if the given neighbour has excess bandwidth available. More...
 
unsigned int GSC_NEIGHBOURS_get_queue_length (const struct GSC_KeyExchangeInfo *target)
 Check how many messages are queued for the given neighbour. More...
 
void GSC_KX_handle_client_monitor_peers (struct GNUNET_MQ_Handle *mq)
 Handle GNUNET_MESSAGE_TYPE_CORE_MONITOR_PEERS request. More...
 

Detailed Description

code for managing the key exchange (SET_KEY, PING, PONG) with other peers

Author
Christian Grothoff

Definition in file gnunet-service-core_kx.h.

Function Documentation

◆ GSC_KX_encrypt_and_transmit()

void GSC_KX_encrypt_and_transmit ( struct GSC_KeyExchangeInfo kx,
const void *  payload,
size_t  payload_size 
)

Encrypt and transmit a message with the given payload.

Parameters
kxkey exchange context
payloadpayload of the message
payload_sizenumber of bytes in 'payload'
kxkey exchange context
payloadpayload of the message
payload_sizenumber of bytes in payload

Definition at line 1516 of file gnunet-service-core_kx.c.

References calculate_seed(), derive_auth_key(), derive_iv(), do_encrypt(), GSC_KeyExchangeInfo::encrypt_key, ENCRYPTED_HEADER_SIZE, env, GNUNET_assert, GNUNET_CRYPTO_hash(), GNUNET_CRYPTO_hmac(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_h2s(), GNUNET_h2s2(), GNUNET_i2s(), GNUNET_log, GNUNET_memcpy, GNUNET_MESSAGE_TYPE_CORE_ENCRYPTED_MESSAGE, GNUNET_MQ_msg_extra, GNUNET_MQ_send(), GNUNET_NO, GNUNET_OK, GNUNET_TIME_absolute_get(), GNUNET_TIME_absolute_hton(), GSC_KeyExchangeInfo::has_excess_bandwidth, EncryptedMessage::hmac, EncryptedMessage::iv_seed, GSC_KeyExchangeInfo::last_sequence_number_sent, GSC_KeyExchangeInfo::mq, GSC_KeyExchangeInfo::peer, ph, and EncryptedMessage::sequence_number.

Referenced by transmit_typemap_task(), and try_transmission().

1519 {
1520  size_t used = payload_size + sizeof(struct EncryptedMessage);
1521  char pbuf[used]; /* plaintext */
1522  struct EncryptedMessage *em; /* encrypted message */
1523  struct EncryptedMessage *ph; /* plaintext header */
1524  struct GNUNET_MQ_Envelope *env;
1526  struct GNUNET_CRYPTO_AuthKey auth_key;
1527 
1528  ph = (struct EncryptedMessage *) pbuf;
1529  ph->sequence_number = htonl (++kx->last_sequence_number_sent);
1530  ph->iv_seed = calculate_seed (kx);
1531  ph->reserved = 0;
1533  GNUNET_memcpy (&ph[1], payload, payload_size);
1534  env = GNUNET_MQ_msg_extra (em,
1535  payload_size,
1537  em->iv_seed = ph->iv_seed;
1538  derive_iv (&iv, &kx->encrypt_key, ph->iv_seed, kx->peer);
1540  &iv,
1541  &ph->sequence_number,
1542  &em->sequence_number,
1543  used - ENCRYPTED_HEADER_SIZE));
1544 #if DEBUG_KX
1545  {
1546  struct GNUNET_HashCode hc;
1547 
1548  GNUNET_CRYPTO_hash (&ph->sequence_number,
1549  used - ENCRYPTED_HEADER_SIZE,
1550  &hc);
1552  "Encrypted payload `%s' of %u bytes for %s\n",
1553  GNUNET_h2s (&hc),
1554  (unsigned int) (used - ENCRYPTED_HEADER_SIZE),
1555  GNUNET_i2s (kx->peer));
1556  }
1557 #endif
1558  derive_auth_key (&auth_key, &kx->encrypt_key, ph->iv_seed);
1559  GNUNET_CRYPTO_hmac (&auth_key,
1560  &em->sequence_number,
1561  used - ENCRYPTED_HEADER_SIZE,
1562  &em->hmac);
1563 #if DEBUG_KX
1564  {
1565  struct GNUNET_HashCode hc;
1566 
1567  GNUNET_CRYPTO_hash (&auth_key, sizeof(auth_key), &hc);
1569  "For peer %s, used AC %s to create hmac %s\n",
1570  GNUNET_i2s (kx->peer),
1571  GNUNET_h2s (&hc),
1572  GNUNET_h2s2 (&em->hmac));
1573  }
1574 #endif
1576  GNUNET_MQ_send (kx->mq, env);
1577 }
const struct GNUNET_PeerIdentity * peer
Identity of the peer.
uint32_t sequence_number
Sequence number, in network byte order.
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
static struct GNUNET_ATS_PerformanceHandle * ph
ATS performance handle used.
Definition: gnunet-ats.c:116
uint32_t last_sequence_number_sent
last sequence number transmitted
static int do_encrypt(struct GSC_KeyExchangeInfo *kx, const struct GNUNET_CRYPTO_SymmetricInitializationVector *iv, const void *in, void *out, size_t size)
Encrypt size bytes from in and write the result to out.
#define GNUNET_memcpy(dst, src, n)
Call memcpy() but check for n being 0 first.
const char * GNUNET_h2s(const struct GNUNET_HashCode *hc)
Convert a hash value to a string (for printing debug messages).
struct GNUNET_HashCode hmac
MAC of the encrypted message (starting at sequence_number), used to verify message integrity...
static void derive_auth_key(struct GNUNET_CRYPTO_AuthKey *akey, const struct GNUNET_CRYPTO_SymmetricSessionKey *skey, uint32_t seed)
Derive an authentication key from "set key" information.
void GNUNET_CRYPTO_hmac(const struct GNUNET_CRYPTO_AuthKey *key, const void *plaintext, size_t plaintext_len, struct GNUNET_HashCode *hmac)
Calculate HMAC of a message (RFC 2104)
Definition: crypto_hash.c:455
struct GNUNET_MQ_Handle * mq
Message queue for sending messages to peer.
const char * GNUNET_h2s2(const struct GNUNET_HashCode *hc)
Convert a hash value to a string (for printing debug messages).
#define GNUNET_MQ_msg_extra(mvar, esize, type)
Allocate an envelope, with extra space allocated after the space needed by the message struct...
Definition: gnunet_mq_lib.h:52
void GNUNET_CRYPTO_hash(const void *block, size_t size, struct GNUNET_HashCode *ret)
Compute hash of a given block.
Definition: crypto_hash.c:48
Encapsulation for encrypted messages exchanged between peers.
A 512-bit hashcode.
struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_get(void)
Get the current time.
Definition: time.c:118
uint32_t iv_seed
Random value used for IV generation.
static uint32_t calculate_seed(struct GSC_KeyExchangeInfo *kx)
Calculate seed value we should use for a message.
struct GNUNET_MQ_Envelope * env
Definition: 005.c:1
static unsigned long long payload
How much data are we currently storing in the database?
#define ENCRYPTED_HEADER_SIZE
Number of bytes (at the beginning) of struct EncryptedMessage that are NOT encrypted.
#define GNUNET_MESSAGE_TYPE_CORE_ENCRYPTED_MESSAGE
Encapsulation for an encrypted message between peers.
static void derive_iv(struct GNUNET_CRYPTO_SymmetricInitializationVector *iv, const struct GNUNET_CRYPTO_SymmetricSessionKey *skey, uint32_t seed, const struct GNUNET_PeerIdentity *identity)
Derive an IV from packet information.
int has_excess_bandwidth
GNUNET_YES if this peer currently has excess bandwidth.
#define GNUNET_log(kind,...)
struct GNUNET_CRYPTO_SymmetricSessionKey encrypt_key
Key we use to encrypt our messages for the other peer (initialized by us when we do the handshake)...
void GNUNET_MQ_send(struct GNUNET_MQ_Handle *mq, struct GNUNET_MQ_Envelope *ev)
Send a message with the given message queue.
Definition: mq.c:355
struct GNUNET_TIME_AbsoluteNBO GNUNET_TIME_absolute_hton(struct GNUNET_TIME_Absolute a)
Convert absolute time to network byte order.
Definition: time.c:657
const char * GNUNET_i2s(const struct GNUNET_PeerIdentity *pid)
Convert a peer identity to a string (for printing debug messages).
type for (message) authentication keys
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◆ GSC_KX_init()

int GSC_KX_init ( struct GNUNET_CRYPTO_EddsaPrivateKey pk)

Initialize KX subsystem.

Parameters
pkprivate key to use for the peer
Returns
GNUNET_OK on success, GNUNET_SYSERR on failure

Definition at line 1911 of file gnunet-service-core_kx.c.

References current_ekm, do_rekey(), EphemeralKeyMessage::ephemeral_key, GNUNET_CRYPTO_ecdhe_key_create(), GNUNET_CRYPTO_eddsa_key_get_public(), GNUNET_CRYPTO_hash(), GNUNET_ERROR_TYPE_INFO, GNUNET_h2s(), GNUNET_log, GNUNET_MESSAGE_TYPE_CORE_ENCRYPTED_MESSAGE, GNUNET_MESSAGE_TYPE_CORE_EPHEMERAL_KEY, GNUNET_MESSAGE_TYPE_CORE_PING, GNUNET_MESSAGE_TYPE_CORE_PONG, GNUNET_MQ_handler_end, GNUNET_MQ_hd_fixed_size, GNUNET_MQ_hd_var_size, GNUNET_notification_context_create(), GNUNET_OK, GNUNET_SCHEDULER_add_delayed(), GNUNET_SYSERR, GNUNET_TRANSPORT_core_connect(), GSC_cfg, GSC_KX_done(), GSC_my_identity, handle_transport_notify_connect(), handle_transport_notify_disconnect(), handle_transport_notify_excess_bw(), my_ephemeral_key, my_private_key, ping(), pk, pong(), GNUNET_PeerIdentity::public_key, REKEY_FREQUENCY, and sign_ephemeral_key().

Referenced by run().

1912 {
1914  { GNUNET_MQ_hd_fixed_size (ephemeral_key,
1916  struct EphemeralKeyMessage,
1917  NULL),
1920  struct PingMessage,
1921  NULL),
1924  struct PongMessage,
1925  NULL),
1926  GNUNET_MQ_hd_var_size (encrypted,
1928  struct EncryptedMessage,
1929  NULL),
1930  GNUNET_MQ_handler_end () };
1931 
1932  my_private_key = *pk;
1936  sign_ephemeral_key ();
1937  {
1938  struct GNUNET_HashCode eh;
1939 
1941  sizeof(current_ekm.ephemeral_key),
1942  &eh);
1944  "Starting with ephemeral key %s\n",
1945  GNUNET_h2s (&eh));
1946  }
1947 
1950  transport =
1952  &GSC_my_identity,
1953  handlers,
1954  NULL,
1958  if (NULL == transport)
1959  {
1960  GSC_KX_done ();
1961  return GNUNET_SYSERR;
1962  }
1963  return GNUNET_OK;
1964 }
static struct GNUNET_CRYPTO_EcdhePrivateKey my_ephemeral_key
Our ephemeral private key.
static void ping(void *cls)
Send a ping to destination.
static void do_rekey(void *cls)
Task run to trigger rekeying.
struct GNUNET_CRYPTO_EcdsaPrivateKey pk
Private key from command line option, or NULL.
Response to a PING.
static struct GNUNET_TRANSPORT_CoreHandle * transport
Transport service.
#define GNUNET_MQ_hd_fixed_size(name, code, str, ctx)
static void handle_transport_notify_excess_bw(void *cls, const struct GNUNET_PeerIdentity *pid, void *connect_cls)
One of our neighbours has excess bandwidth, remember this.
const char * GNUNET_h2s(const struct GNUNET_HashCode *hc)
Convert a hash value to a string (for printing debug messages).
static void sign_ephemeral_key()
Setup the message that links the ephemeral key to our persistent public key and generate the appropri...
struct GNUNET_TRANSPORT_CoreHandle * GNUNET_TRANSPORT_core_connect(const struct GNUNET_CONFIGURATION_Handle *cfg, const struct GNUNET_PeerIdentity *self, const struct GNUNET_MQ_MessageHandler *handlers, void *cls, GNUNET_TRANSPORT_NotifyConnect nc, GNUNET_TRANSPORT_NotifyDisconnect nd)
Connect to the transport service.
#define GNUNET_MESSAGE_TYPE_CORE_PONG
Confirmation that other peer is alive.
void GNUNET_CRYPTO_ecdhe_key_create(struct GNUNET_CRYPTO_EcdhePrivateKey *pk)
Create a new private key.
Definition: crypto_ecc.c:508
struct GNUNET_SCHEDULER_Task * GNUNET_SCHEDULER_add_delayed(struct GNUNET_TIME_Relative delay, GNUNET_SCHEDULER_TaskCallback task, void *task_cls)
Schedule a new task to be run with a specified delay.
Definition: scheduler.c:1269
static struct GNUNET_CRYPTO_EddsaPrivateKey my_private_key
Our private key.
static struct GNUNET_CADET_MessageHandler handlers[]
Handlers, for diverse services.
We're sending an (encrypted) PING to the other peer to check if it can decrypt.
#define GNUNET_MQ_hd_var_size(name, code, str, ctx)
void GNUNET_CRYPTO_hash(const void *block, size_t size, struct GNUNET_HashCode *ret)
Compute hash of a given block.
Definition: crypto_hash.c:48
Encapsulation for encrypted messages exchanged between peers.
A 512-bit hashcode.
Message handler for a specific message type.
#define GNUNET_MESSAGE_TYPE_CORE_EPHEMERAL_KEY
Session key exchange between peers.
struct GNUNET_PeerIdentity GSC_my_identity
Our identity.
static void pong(struct GNUNET_CADET_Channel *channel, const struct CadetPingMessage *ping)
Reply with a pong to origin.
struct GNUNET_CRYPTO_EcdhePublicKey ephemeral_key
Ephemeral public ECC key.
static void * handle_transport_notify_connect(void *cls, const struct GNUNET_PeerIdentity *pid, struct GNUNET_MQ_Handle *mq)
Function called by transport to notify us that a peer connected to us (on the network level)...
#define GNUNET_MESSAGE_TYPE_CORE_PING
Check that other peer is alive (challenge).
static struct GNUNET_NotificationContext * nc
Notification context for broadcasting to monitors.
void GNUNET_CRYPTO_eddsa_key_get_public(const struct GNUNET_CRYPTO_EddsaPrivateKey *priv, struct GNUNET_CRYPTO_EddsaPublicKey *pub)
Extract the public key for the given private key.
Definition: crypto_ecc.c:193
struct GNUNET_NotificationContext * GNUNET_notification_context_create(unsigned int queue_length)
Create a new notification context.
Definition: nc.c:121
#define GNUNET_MESSAGE_TYPE_CORE_ENCRYPTED_MESSAGE
Encapsulation for an encrypted message between peers.
static struct GNUNET_SCHEDULER_Task * rekey_task
Task scheduled for periodic re-generation (and thus rekeying) of our ephemeral key.
#define REKEY_FREQUENCY
How often do we rekey?
#define GNUNET_log(kind,...)
static struct EphemeralKeyMessage current_ekm
Current message we send for a key exchange.
static void handle_transport_notify_disconnect(void *cls, const struct GNUNET_PeerIdentity *peer, void *handler_cls)
Function called by transport telling us that a peer disconnected.
Message transmitted with the signed ephemeral key of a peer.
void GSC_KX_done()
Shutdown KX subsystem.
#define GNUNET_MQ_handler_end()
End-marker for the handlers array.
const struct GNUNET_CONFIGURATION_Handle * GSC_cfg
Our configuration.
struct GNUNET_CRYPTO_EddsaPublicKey public_key
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◆ GSC_KX_done()

void GSC_KX_done ( void  )

Shutdown KX subsystem.

Definition at line 1971 of file gnunet-service-core_kx.c.

References GNUNET_notification_context_destroy(), GNUNET_SCHEDULER_cancel(), GNUNET_TRANSPORT_core_disconnect(), my_ephemeral_key, and my_private_key.

Referenced by GSC_KX_init(), and shutdown_task().

1972 {
1973  if (NULL != transport)
1974  {
1976  transport = NULL;
1977  }
1978  if (NULL != rekey_task)
1979  {
1981  rekey_task = NULL;
1982  }
1983  memset (&my_ephemeral_key,
1984  0,
1985  sizeof (my_ephemeral_key));
1986  memset (&my_private_key,
1987  0,
1988  sizeof (my_private_key));
1989  if (NULL != nc)
1990  {
1992  nc = NULL;
1993  }
1994 }
static struct GNUNET_CRYPTO_EcdhePrivateKey my_ephemeral_key
Our ephemeral private key.
static struct GNUNET_TRANSPORT_CoreHandle * transport
Transport service.
static struct GNUNET_CRYPTO_EddsaPrivateKey my_private_key
Our private key.
static struct GNUNET_NotificationContext * nc
Notification context for broadcasting to monitors.
static struct GNUNET_SCHEDULER_Task * rekey_task
Task scheduled for periodic re-generation (and thus rekeying) of our ephemeral key.
void GNUNET_TRANSPORT_core_disconnect(struct GNUNET_TRANSPORT_CoreHandle *handle)
Disconnect from the transport service.
void GNUNET_notification_context_destroy(struct GNUNET_NotificationContext *nc)
Destroy the context, force disconnect for all subscribers.
Definition: nc.c:137
void * GNUNET_SCHEDULER_cancel(struct GNUNET_SCHEDULER_Task *task)
Cancel the task with the specified identifier.
Definition: scheduler.c:972
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◆ GSC_NEIGHBOURS_check_excess_bandwidth()

int GSC_NEIGHBOURS_check_excess_bandwidth ( const struct GSC_KeyExchangeInfo kxinfo)

Check if the given neighbour has excess bandwidth available.

Parameters
targetneighbour to check
Returns
GNUNET_YES if excess bandwidth is available, GNUNET_NO if not

Definition at line 2017 of file gnunet-service-core_kx.c.

References GSC_KeyExchangeInfo::has_excess_bandwidth.

Referenced by try_transmission().

2018 {
2019  return kxinfo->has_excess_bandwidth;
2020 }
int has_excess_bandwidth
GNUNET_YES if this peer currently has excess bandwidth.
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◆ GSC_NEIGHBOURS_get_queue_length()

unsigned int GSC_NEIGHBOURS_get_queue_length ( const struct GSC_KeyExchangeInfo kxinfo)

Check how many messages are queued for the given neighbour.

Parameters
targetneighbour to check
Returns
number of items in the message queue
Parameters
kxinfodata about neighbour to check
Returns
number of items in the message queue

Definition at line 2004 of file gnunet-service-core_kx.c.

References GNUNET_MQ_get_length(), and GSC_KeyExchangeInfo::mq.

Referenced by try_transmission().

2005 {
2006  return GNUNET_MQ_get_length (kxinfo->mq);
2007 }
struct GNUNET_MQ_Handle * mq
Message queue for sending messages to peer.
unsigned int GNUNET_MQ_get_length(struct GNUNET_MQ_Handle *mq)
Obtain the current length of the message queue.
Definition: mq.c:337
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◆ GSC_KX_handle_client_monitor_peers()

void GSC_KX_handle_client_monitor_peers ( struct GNUNET_MQ_Handle mq)

Handle GNUNET_MESSAGE_TYPE_CORE_MONITOR_PEERS request.

For this request type, the client does not have to have transmitted an INIT request. All current peers are returned, regardless of which message types they accept.

Parameters
mqmessage queue to add for monitoring

Definition at line 2032 of file gnunet-service-core_kx.c.

References env, GNUNET_CORE_KX_ITERATION_FINISHED, GNUNET_MESSAGE_TYPE_CORE_MONITOR_NOTIFY, GNUNET_MQ_msg, GNUNET_MQ_send(), GNUNET_notification_context_add(), GNUNET_TIME_absolute_hton(), GNUNET_TIME_UNIT_FOREVER_ABS, msg, GSC_KeyExchangeInfo::next, GSC_KeyExchangeInfo::peer, MonitorNotifyMessage::peer, MonitorNotifyMessage::state, GSC_KeyExchangeInfo::status, GSC_KeyExchangeInfo::timeout, and MonitorNotifyMessage::timeout.

Referenced by handle_client_monitor_peers().

2033 {
2034  struct GNUNET_MQ_Envelope *env;
2035  struct MonitorNotifyMessage *done_msg;
2036  struct GSC_KeyExchangeInfo *kx;
2037 
2039  for (kx = kx_head; NULL != kx; kx = kx->next)
2040  {
2041  struct GNUNET_MQ_Envelope *env;
2042  struct MonitorNotifyMessage *msg;
2043 
2045  msg->state = htonl ((uint32_t) kx->status);
2046  msg->peer = *kx->peer;
2048  GNUNET_MQ_send (mq, env);
2049  }
2051  done_msg->state = htonl ((uint32_t) GNUNET_CORE_KX_ITERATION_FINISHED);
2053  GNUNET_MQ_send (mq, env);
2054 }
struct GNUNET_MessageHeader * msg
Definition: 005.c:2
const struct GNUNET_PeerIdentity * peer
Identity of the peer.
enum GNUNET_CORE_KxState status
What is our connection status?
struct GNUNET_TIME_AbsoluteNBO timeout
How long will we stay in this state (if nothing else happens)?
Definition: core.h:322
#define GNUNET_MQ_msg(mvar, type)
Allocate a GNUNET_MQ_Envelope.
Definition: gnunet_mq_lib.h:67
static struct GSC_KeyExchangeInfo * kx_head
DLL head.
void GNUNET_notification_context_add(struct GNUNET_NotificationContext *nc, struct GNUNET_MQ_Handle *mq)
Add a subscriber to the notification context.
Definition: nc.c:160
#define GNUNET_TIME_UNIT_FOREVER_ABS
Constant used to specify "forever".
struct GSC_KeyExchangeInfo * next
DLL.
Information about the status of a key exchange with another peer.
This is not a state in a peer's state machine, but a special value used with the GNUNET_CORE_MonitorC...
struct GNUNET_MQ_Envelope * env
Definition: 005.c:1
static struct GNUNET_NotificationContext * nc
Notification context for broadcasting to monitors.
uint32_t state
New peer state, an enum GNUNET_CORE_KxState in NBO.
Definition: core.h:312
struct GNUNET_TIME_Absolute timeout
When should the session time out (if there are no PONGs)?
void GNUNET_MQ_send(struct GNUNET_MQ_Handle *mq, struct GNUNET_MQ_Envelope *ev)
Send a message with the given message queue.
Definition: mq.c:355
Message sent by the service to monitor clients to notify them about a peer changing status...
Definition: core.h:302
struct GNUNET_TIME_AbsoluteNBO GNUNET_TIME_absolute_hton(struct GNUNET_TIME_Absolute a)
Convert absolute time to network byte order.
Definition: time.c:657
#define GNUNET_MESSAGE_TYPE_CORE_MONITOR_NOTIFY
Reply for monitor by CORE service.
struct GNUNET_PeerIdentity peer
Identity of the peer.
Definition: core.h:317
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