diff --git a/toxcore/onion.c b/toxcore/onion.c
index 3c4d2ad1..6c62b7bb 100644
--- a/toxcore/onion.c
+++ b/toxcore/onion.c
@@ -54,7 +54,7 @@ static void change_symmetric_key(Onion *onion)
  * return -1 on failure.
  * return 0 on success.
  */
-int create_onion_path(DHT *dht, Onion_Path *new_path, Node_format *nodes)
+int create_onion_path(const DHT *dht, Onion_Path *new_path, const Node_format *nodes)
 {
     if (!new_path || !nodes)
         return -1;
@@ -149,7 +149,7 @@ int create_onion_packet(uint8_t *packet, uint16_t max_packet_length, const Onion
  * return -1 on failure.
  * return 0 on success.
  */
-int send_onion_packet(Networking_Core *net, Onion_Path *path, IP_Port dest, uint8_t *data, uint32_t length)
+int send_onion_packet(Networking_Core *net, const Onion_Path *path, IP_Port dest, const uint8_t *data, uint32_t length)
 {
     uint8_t packet[ONION_MAX_PACKET_SIZE];
     int len = create_onion_packet(packet, sizeof(packet), path, dest, data, length);
@@ -209,7 +209,7 @@ static int handle_send_initial(void *object, IP_Port source, const uint8_t *pack
     return onion_send_1(onion, plain, len, source, packet + 1);
 }
 
-int onion_send_1(Onion *onion, uint8_t *plain, uint32_t len, IP_Port source, const uint8_t *nonce)
+int onion_send_1(const Onion *onion, const uint8_t *plain, uint32_t len, IP_Port source, const uint8_t *nonce)
 {
     IP_Port send_to;
     ipport_unpack(&send_to, plain);
diff --git a/toxcore/onion.h b/toxcore/onion.h
index 0ba724c6..2e71db7e 100644
--- a/toxcore/onion.h
+++ b/toxcore/onion.h
@@ -76,7 +76,7 @@ typedef struct {
  * return -1 on failure.
  * return 0 on success.
  */
-int create_onion_path(DHT *dht, Onion_Path *new_path, Node_format *nodes);
+int create_onion_path(const DHT *dht, Onion_Path *new_path, const Node_format *nodes);
 
 /* Create a onion packet.
  *
@@ -98,7 +98,7 @@ int create_onion_packet(uint8_t *packet, uint16_t max_packet_length, const Onion
  * return -1 on failure.
  * return 0 on success.
  */
-int send_onion_packet(Networking_Core *net, Onion_Path *path, IP_Port dest, uint8_t *data, uint32_t length);
+int send_onion_packet(Networking_Core *net, const Onion_Path *path, IP_Port dest, const uint8_t *data, uint32_t length);
 
 /* Create and send a onion response sent initially to dest with.
  * Maximum length of data is ONION_RESPONSE_MAX_DATA_SIZE.
@@ -118,7 +118,7 @@ int send_onion_response(Networking_Core *net, IP_Port dest, const uint8_t *data,
  * Source family must be set to something else than AF_INET6 or AF_INET so that the callback gets called
  * when the response is received.
  */
-int onion_send_1(Onion *onion, uint8_t *plain, uint32_t len, IP_Port source, const uint8_t *nonce);
+int onion_send_1(const Onion *onion, const uint8_t *plain, uint32_t len, IP_Port source, const uint8_t *nonce);
 
 /* Set the callback to be called when the dest ip_port doesn't have AF_INET6 or AF_INET as the family.
  *