GNUnet 0.21.2
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"
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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)

Detailed Description

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

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.

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

Definition at line 1423 of file gnunet-service-core_kx.c.

1427 size_t used = payload_size + sizeof(struct EncryptedMessage);
1428 char pbuf[used]; /* plaintext */
1429 struct EncryptedMessage *em; /* encrypted message */
1430 struct EncryptedMessage *ph; /* plaintext header */
1431 struct GNUNET_MQ_Envelope *env;
1433 struct GNUNET_CRYPTO_AuthKey auth_key;
1435 ph = (struct EncryptedMessage *) pbuf;
1436 ph->sequence_number = htonl (++kx->last_sequence_number_sent);
1437 ph->iv_seed = calculate_seed (kx);
1438 ph->reserved = 0;
1440 GNUNET_memcpy (&ph[1], payload, payload_size);
1442 payload_size,
1444 em->iv_seed = ph->iv_seed;
1445 derive_iv (&iv, &kx->encrypt_key, ph->iv_seed, kx->peer);
1447 &iv,
1448 &ph->sequence_number,
1449 &em->sequence_number,
1451#if DEBUG_KX
1452 {
1453 struct GNUNET_HashCode hc;
1457 &hc);
1459 "Encrypted payload `%s' of %u bytes for %s\n",
1460 GNUNET_h2s (&hc),
1461 (unsigned int) (used - ENCRYPTED_HEADER_SIZE),
1462 GNUNET_i2s (kx->peer));
1463 }
1465 derive_auth_key (&auth_key, &kx->encrypt_key, ph->iv_seed);
1466 GNUNET_CRYPTO_hmac (&auth_key,
1467 &em->sequence_number,
1469 &em->hmac);
1470#if DEBUG_KX
1471 {
1472 struct GNUNET_HashCode hc;
1474 GNUNET_CRYPTO_hash (&auth_key, sizeof(auth_key), &hc);
1476 "For peer %s, used AC %s to create hmac %s\n",
1477 GNUNET_i2s (kx->peer),
1478 GNUNET_h2s (&hc),
1479 GNUNET_h2s2 (&em->hmac));
1480 }
1483 GNUNET_MQ_send (kx->mq, env);
struct GNUNET_MQ_Envelope * env
Definition: 005.c:1
static uint32_t calculate_seed(struct GSC_KeyExchangeInfo *kx)
Calculate seed value we should use for a message.
Number of bytes (at the beginning) of struct EncryptedMessage that are NOT encrypted.
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.
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.
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.
static unsigned long long payload
How much data are we currently storing in the database?
void GNUNET_CRYPTO_hash(const void *block, size_t size, struct GNUNET_HashCode *ret)
Compute hash of a given block.
Definition: crypto_hash.c:41
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:330
#define GNUNET_log(kind,...)
#define GNUNET_memcpy(dst, src, n)
Call memcpy() but check for n being 0 first.
const char * GNUNET_i2s(const struct GNUNET_PeerIdentity *pid)
Convert a peer identity to a string (for printing debug messages).
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
const char * GNUNET_h2s(const struct GNUNET_HashCode *hc)
Convert a hash value to a string (for printing debug messages).
const char * GNUNET_h2s2(const struct GNUNET_HashCode *hc)
Convert a hash value to a string (for printing debug messages).
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:304
#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:63
Encapsulation for an encrypted message between peers.
struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_get(void)
Get the current time.
Definition: time.c:111
struct GNUNET_TIME_AbsoluteNBO GNUNET_TIME_absolute_hton(struct GNUNET_TIME_Absolute a)
Convert absolute time to network byte order.
Definition: time.c:638
Encapsulation for encrypted messages exchanged between peers.
uint32_t iv_seed
Random value used for IV generation.
struct GNUNET_TIME_AbsoluteNBO timestamp
uint32_t sequence_number
Sequence number, in network byte order.
struct GNUNET_HashCode hmac
MAC of the encrypted message (starting at sequence_number), used to verify message integrity.
uint32_t reserved
Reserved, always zero.
type for (message) authentication keys
A 512-bit hashcode.
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).
const struct GNUNET_PeerIdentity * peer
Identity of the peer.
uint32_t last_sequence_number_sent
last sequence number transmitted
struct GNUNET_MQ_Handle * mq
Message queue for sending messages to peer.
int has_excess_bandwidth
GNUNET_YES if this peer currently has excess bandwidth.

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, payload, GSC_KeyExchangeInfo::peer, EncryptedMessage::reserved, EncryptedMessage::sequence_number, and EncryptedMessage::timestamp.

Referenced by transmit_typemap_task(), and try_transmission().

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◆ GSC_KX_init()

int GSC_KX_init ( struct GNUNET_CRYPTO_EddsaPrivateKey pk)

Initialize KX subsystem.

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

Definition at line 1805 of file gnunet-service-core_kx.c.

1808 GNUNET_MQ_hd_fixed_size (ephemeral_key,
1810 struct EphemeralKeyMessage,
1811 NULL),
1814 struct PingMessage,
1815 NULL),
1818 struct PongMessage,
1819 NULL),
1820 GNUNET_MQ_hd_var_size (encrypted,
1822 struct EncryptedMessage,
1823 NULL),
1825 };
1827 my_private_key = *pk;
1832 {
1833 struct GNUNET_HashCode eh;
1836 sizeof(current_ekm.ephemeral_key),
1837 &eh);
1839 "Starting with ephemeral key %s\n",
1840 GNUNET_h2s (&eh));
1841 }
1845 transport =
1848 handlers,
1849 NULL,
1852 if (NULL == transport)
1853 {
1854 GSC_KX_done ();
1855 return GNUNET_SYSERR;
1856 }
1857 return GNUNET_OK;
struct GNUNET_MQ_MessageHandlers handlers[]
Definition: 003.c:1
struct GNUNET_CRYPTO_PrivateKey pk
Private key from command line option, or NULL.
const struct GNUNET_CONFIGURATION_Handle * GSC_cfg
Our configuration.
struct GNUNET_PeerIdentity GSC_my_identity
Our identity.
static struct GNUNET_CRYPTO_EddsaPrivateKey my_private_key
Our private key.
static struct GNUNET_CRYPTO_EcdhePrivateKey my_ephemeral_key
Our ephemeral private key.
How often do we rekey?
static void sign_ephemeral_key()
Setup the message that links the ephemeral key to our persistent public key and generate the appropri...
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.
static struct GNUNET_NotificationContext * nc
Notification context for broadcasting to monitors.
static struct EphemeralKeyMessage current_ekm
Current message we send for a key exchange.
static void do_rekey(void *cls)
Task run to trigger rekeying.
void GSC_KX_done()
Shutdown KX subsystem.
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).
static struct GNUNET_SCHEDULER_Task * rekey_task
Task scheduled for periodic re-generation (and thus rekeying) of our ephemeral key.
static struct GNUNET_TRANSPORT_CoreHandle * transport
Transport service.
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.
void GNUNET_CRYPTO_ecdhe_key_create(struct GNUNET_CRYPTO_EcdhePrivateKey *pk)
Create a new private key.
Definition: crypto_ecc.c:451
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:198
#define GNUNET_MQ_handler_end()
End-marker for the handlers array.
struct GNUNET_NotificationContext * GNUNET_notification_context_create(unsigned int queue_length)
Create a new notification context.
Definition: nc.c:122
#define GNUNET_MQ_hd_var_size(name, code, str, ctx)
#define GNUNET_MQ_hd_fixed_size(name, code, str, ctx)
Check that other peer is alive (challenge).
Confirmation that other peer is alive.
Session key exchange between peers.
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:1278
Message transmitted with the signed ephemeral key of a peer.
struct GNUNET_CRYPTO_EcdhePublicKey ephemeral_key
Ephemeral public ECC key.
Message handler for a specific message type.
struct GNUNET_CRYPTO_EddsaPublicKey public_key
We're sending an (encrypted) PING to the other peer to check if it can decrypt.
Response to a PING.

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(), handlers, my_ephemeral_key, my_private_key, nc, pk, GNUNET_PeerIdentity::public_key, REKEY_FREQUENCY, rekey_task, sign_ephemeral_key(), and transport.

Referenced by run().

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◆ GSC_KX_done()

void GSC_KX_done ( void  )

Shutdown KX subsystem.

Definition at line 1865 of file gnunet-service-core_kx.c.

1867 if (NULL != transport)
1868 {
1870 transport = NULL;
1871 }
1872 if (NULL != rekey_task)
1873 {
1875 rekey_task = NULL;
1876 }
1877 memset (&my_ephemeral_key,
1878 0,
1879 sizeof (my_ephemeral_key));
1880 memset (&my_private_key,
1881 0,
1882 sizeof (my_private_key));
1883 if (NULL != nc)
1884 {
1886 nc = NULL;
1887 }
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:138
void * GNUNET_SCHEDULER_cancel(struct GNUNET_SCHEDULER_Task *task)
Cancel the task with the specified identifier.
Definition: scheduler.c:981

References GNUNET_notification_context_destroy(), GNUNET_SCHEDULER_cancel(), GNUNET_TRANSPORT_core_disconnect(), my_ephemeral_key, my_private_key, nc, rekey_task, and transport.

Referenced by GSC_KX_init(), and shutdown_task().

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◆ GSC_NEIGHBOURS_check_excess_bandwidth()

int GSC_NEIGHBOURS_check_excess_bandwidth ( const struct GSC_KeyExchangeInfo target)

Check if the given neighbour has excess bandwidth available.

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

Definition at line 1905 of file gnunet-service-core_kx.c.

1907 return kxinfo->has_excess_bandwidth;

References GSC_KeyExchangeInfo::has_excess_bandwidth.

Referenced by try_transmission().

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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.

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

Definition at line 1898 of file gnunet-service-core_kx.c.

1900 return GNUNET_MQ_get_length (kxinfo->mq);
unsigned int GNUNET_MQ_get_length(struct GNUNET_MQ_Handle *mq)
Obtain the current length of the message queue.
Definition: mq.c:293

References GNUNET_MQ_get_length(), and GSC_KeyExchangeInfo::mq.

Referenced by try_transmission().

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◆ GSC_KX_handle_client_monitor_peers()

void GSC_KX_handle_client_monitor_peers ( struct GNUNET_MQ_Handle mq)


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.

mqmessage queue to add for monitoring

Definition at line 1920 of file gnunet-service-core_kx.c.

1922 struct GNUNET_MQ_Envelope *env;
1923 struct MonitorNotifyMessage *done_msg;
1924 struct GSC_KeyExchangeInfo *kx;
1927 for (kx = kx_head; NULL != kx; kx = kx->next)
1928 {
1929 struct GNUNET_MQ_Envelope *env;
1930 struct MonitorNotifyMessage *msg;
1933 msg->state = htonl ((uint32_t) kx->status);
1934 msg->peer = *kx->peer;
1935 msg->timeout = GNUNET_TIME_absolute_hton (kx->timeout);
1937 }
1939 done_msg->state = htonl ((uint32_t) GNUNET_CORE_KX_ITERATION_FINISHED);
struct GNUNET_MQ_Handle * mq
Definition: 003.c:5
struct GNUNET_MessageHeader * msg
Definition: 005.c:2
static struct GSC_KeyExchangeInfo * kx_head
DLL head.
This is not a state in a peer's state machine, but a special value used with the GNUNET_CORE_MonitorC...
#define GNUNET_MQ_msg(mvar, type)
Allocate a GNUNET_MQ_Envelope.
Definition: gnunet_mq_lib.h:78
void GNUNET_notification_context_add(struct GNUNET_NotificationContext *nc, struct GNUNET_MQ_Handle *mq)
Add a subscriber to the notification context.
Definition: nc.c:161
Reply for monitor by CORE service.
Constant used to specify "forever".
Information about the status of a key exchange with another peer.
struct GSC_KeyExchangeInfo * next
struct GNUNET_TIME_Absolute timeout
When should the session time out (if there are no PONGs)?
enum GNUNET_CORE_KxState status
What is our connection status?
Message sent by the service to monitor clients to notify them about a peer changing status.
Definition: core.h:301
uint32_t state
New peer state, an enum GNUNET_CORE_KxState in NBO.
Definition: core.h:310
struct GNUNET_TIME_AbsoluteNBO timeout
How long will we stay in this state (if nothing else happens)?
Definition: core.h:320

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, kx_head, mq, msg, nc, GSC_KeyExchangeInfo::next, GSC_KeyExchangeInfo::peer, MonitorNotifyMessage::state, GSC_KeyExchangeInfo::status, MonitorNotifyMessage::timeout, and GSC_KeyExchangeInfo::timeout.

Referenced by handle_client_monitor_peers().

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