1 files changed, 229 insertions, 0 deletions

diff --git a/toxcore/ping.c b/toxcore/ping.c
new file mode 100644
index 00000000..55d4d261
--- /dev/null
+++ b/toxcore/ping.c
@@ -0,0 +1,229 @@
+/*
+ * ping.c -- Buffered pinging using cyclic arrays.
+ *
+ * This file is donated to the Tox Project.
+ * Copyright 2013  plutooo
+ */
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "DHT.h"
+#include "net_crypto.h"
+#include "packets.h"
+#include "network.h"
+#include "util.h"
+
+#define PING_NUM_MAX 256
+#define PING_TIMEOUT 5 // 5s
+
+typedef struct {
+    IP_Port  ipp;
+    uint64_t id;
+    uint64_t timestamp;
+} pinged_t;
+
+typedef struct {
+    pinged_t    pings[PING_NUM_MAX];
+    size_t      num_pings;
+    size_t      pos_pings;
+} PING;
+
+void *new_ping(void)
+{
+    return calloc(1, sizeof(PING));
+}
+
+void kill_ping(void *ping)
+{
+    free(ping);
+}
+
+static bool is_timeout(uint64_t time)
+{
+    return (time + PING_TIMEOUT) < now();
+}
+
+static void remove_timeouts(void *ping)    // O(n)
+{
+    PING *png = ping;
+    size_t i, id;
+    size_t new_pos = png->pos_pings;
+    size_t new_num = png->num_pings;
+
+    // Loop through buffer, oldest first
+    for (i = 0; i < png->num_pings; i++) {
+        id = (png->pos_pings + i) % PING_NUM_MAX;
+
+        if (is_timeout(png->pings[id].timestamp)) {
+            new_pos++;
+            new_num--;
+        }
+        // Break here because list is sorted.
+        else {
+            break;
+        }
+    }
+
+    png->num_pings = new_num;
+    png->pos_pings = new_pos % PING_NUM_MAX;
+}
+
+uint64_t add_ping(void *ping, IP_Port ipp)  // O(n)
+{
+    PING *png = ping;
+    size_t p;
+
+    remove_timeouts(ping);
+
+    // Remove oldest ping if full buffer
+    if (png->num_pings == PING_NUM_MAX) {
+        png->num_pings--;
+        png->pos_pings = (png->pos_pings + 1) % PING_NUM_MAX;
+    }
+
+    // Insert new ping at end of list
+    p = (png->pos_pings + png->num_pings) % PING_NUM_MAX;
+
+    png->pings[p].ipp       = ipp;
+    png->pings[p].timestamp = now();
+    png->pings[p].id        = random_64b();
+
+    png->num_pings++;
+    return png->pings[p].id;
+}
+
+bool is_pinging(void *ping, IP_Port ipp, uint64_t ping_id)    // O(n) TODO: replace this with something else.
+{
+    PING *png = ping;
+
+    if (ipp.ip.i == 0 && ping_id == 0)
+        return false;
+
+    size_t i, id;
+
+    remove_timeouts(ping);
+
+    for (i = 0; i < png->num_pings; i++) {
+        id = (png->pos_pings + i) % PING_NUM_MAX;
+
+        // ping_id = 0 means match any id
+        if ((ipp_eq(png->pings[id].ipp, ipp) || ipp.ip.i == 0) && (png->pings[id].id == ping_id || ping_id == 0)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+int send_ping_request(void *ping, Net_Crypto *c, IP_Port ipp, clientid_t *client_id)
+{
+    pingreq_t pk;
+    int       rc;
+    uint64_t  ping_id;
+
+    if (is_pinging(ping, ipp, 0) || id_eq(client_id, (clientid_t *)c->self_public_key))
+        return 1;
+
+    // Generate random ping_id
+    ping_id = add_ping(ping, ipp);
+
+    pk.packet_id = NET_PACKET_PING_REQUEST;
+    id_cpy(&pk.client_id, (clientid_t *)c->self_public_key);     // Our pubkey
+    random_nonce((uint8_t *) &pk.nonce); // Generate random nonce
+
+    // Encrypt ping_id using recipient privkey
+    rc = encrypt_data((uint8_t *) client_id,
+                      c->self_secret_key,
+                      (uint8_t *) &pk.nonce,
+                      (uint8_t *) &ping_id, sizeof(ping_id),
+                      (uint8_t *) &pk.ping_id);
+
+    if (rc != sizeof(ping_id) + ENCRYPTION_PADDING)
+        return 1;
+
+    return sendpacket(c->lossless_udp->net->sock, ipp, (uint8_t *) &pk, sizeof(pk));
+}
+
+int send_ping_response(Net_Crypto *c, IP_Port ipp, clientid_t *client_id, uint64_t ping_id)
+{
+    pingres_t pk;
+    int       rc;
+
+    if (id_eq(client_id, (clientid_t *)c->self_public_key))
+        return 1;
+
+    pk.packet_id = NET_PACKET_PING_RESPONSE;
+    id_cpy(&pk.client_id, (clientid_t *)c->self_public_key);     // Our pubkey
+    random_nonce((uint8_t *) &pk.nonce); // Generate random nonce
+
+    // Encrypt ping_id using recipient privkey
+    rc = encrypt_data((uint8_t *) client_id,
+                      c->self_secret_key,
+                      (uint8_t *) &pk.nonce,
+                      (uint8_t *) &ping_id, sizeof(ping_id),
+                      (uint8_t *) &pk.ping_id);
+
+    if (rc != sizeof(ping_id) + ENCRYPTION_PADDING)
+        return 1;
+
+    return sendpacket(c->lossless_udp->net->sock, ipp, (uint8_t *) &pk, sizeof(pk));
+}
+
+int handle_ping_request(void *object, IP_Port source, uint8_t *packet, uint32_t length)
+{
+    DHT *dht = object;
+    pingreq_t *p = (pingreq_t *) packet;
+    int        rc;
+    uint64_t   ping_id;
+
+    if (length != sizeof(pingreq_t) || id_eq(&p->client_id, (clientid_t *)dht->c->self_public_key))
+        return 1;
+
+    // Decrypt ping_id
+    rc = decrypt_data((uint8_t *) &p->client_id,
+                      dht->c->self_secret_key,
+                      (uint8_t *) &p->nonce,
+                      (uint8_t *) &p->ping_id,
+                      sizeof(ping_id) + ENCRYPTION_PADDING,
+                      (uint8_t *) &ping_id);
+
+    if (rc != sizeof(ping_id))
+        return 1;
+
+    // Send response
+    send_ping_response(dht->c, source, &p->client_id, ping_id);
+    add_toping(dht, (uint8_t *) &p->client_id, source);
+
+    return 0;
+}
+
+int handle_ping_response(void *object, IP_Port source, uint8_t *packet, uint32_t length)
+{
+    DHT *dht = object;
+    pingres_t *p = (pingres_t *) packet;
+    int       rc;
+    uint64_t  ping_id;
+
+    if (length != sizeof(pingres_t) || id_eq(&p->client_id, (clientid_t *)dht->c->self_public_key))
+        return 1;
+
+    // Decrypt ping_id
+    rc = decrypt_data((uint8_t *) &p->client_id,
+                      dht->c->self_secret_key,
+                      (uint8_t *) &p->nonce,
+                      (uint8_t *) &p->ping_id,
+                      sizeof(ping_id) + ENCRYPTION_PADDING,
+                      (uint8_t *) &ping_id);
+
+    if (rc != sizeof(ping_id))
+        return 1;
+
+    // Make sure ping_id is correct
+    if (!is_pinging(dht->ping, source, ping_id))
+        return 1;
+
+    // Associate source ip with client_id
+    addto_lists(dht, source, (uint8_t *) &p->client_id);
+    return 0;
+}