[WIP] 20% wireguard

tunnels/shared/wireguard/defs.h

@@ -1,22 +1,47 @@
 #pragma once
 
+/*
+    Most of the code is taken and renamed, from the awesome projects wireguard-lwip and lwip
+
+    Author of lwip:              Adam Dunkels  https://github.com/smartalock/wireguard-lwip
+    Author of wireguard-lwip:    Daniel Hope   https://github.com/lwip-tcpip/lwip
+
+    their license files are placed next to this file
+*/
+
 #include <stdbool.h>
 #include <stdint.h>
 
+struct ip4_addr {
+  uint32_t addr;
+};
+typedef struct ip4_addr ip4_addr_t;
+
+enum wg_general_limits
+{
+    // Peers are allocated statically inside the device structure to avoid malloc
+    kWgMaxPeers  = 1,
+    kWgMaxSrcIPs = 2,
+    // Per device limit on accepting (valid) initiation requests - per peer
+    kMaxInitiationPerSecond = 2
+};
+
 enum wg_general_consts
 {
-    kWgAuthLen            = 16,
-    kWgHashLen            = 32,
-    kWgPublicKeyLen       = 32,
-    kWgSessionKeyLen      = 32,
-    kWgPrivateKeyLen      = 32,
-    kWgTai64Len           = 12,
-    kWgCookieLen          = 16,
-    kWgCookieNonceLen     = 24,
-    kWgReKeyAfterMessages = (1ULL << 60),
-    kWgRejectAfterMessage = (0XFFFFFFFFFFFFFFFFULL - (1ULL << 13))
+    kWgAuthTagLen     = 16,
+    kWgHashLen        = 32,
+    kWgPublicKeyLen   = 32,
+    kWgSessionKeyLen  = 32,
+    kWgPrivateKeyLen  = 32,
+    kWgTai64Len       = 12,
+    kWgCookieLen      = 16,
+    kWgCookieNonceLen = 24
 };
 
+// ISO C restricts enumerator values to range of 'int' (1152921504606846976) is too large
+#define kWgReKeyAfterMessages (1ULL << 60)                           // NOLINT
+#define kWgRejectAfterMessage (0XFFFFFFFFFFFFFFFFULL - (1ULL << 13)) // NOLINT
+
 enum wg_timing_consts
 {
     kWgCookieSecretMaxDuration = 120,
@@ -66,3 +91,142 @@ typedef struct wireguard_handshake_s
     uint8_t  chaining_key[kWgHashLen];
 
 } wireguard_handshake_t;
+
+typedef struct wireguard_allowed_ip_s {
+	bool valid;
+	ip_addr_t ip;
+	ip_addr_t mask;
+} wireguard_allowed_ip_t;
+
+struct wireguard_peer
+{
+    bool valid;  // Is this peer initialised?
+    bool active; // Should we be actively trying to connect?
+
+    // This is the configured IP of the peer (endpoint)
+    ip_addr_t connect_ip;
+    uint16_t  connect_port;
+    // This is the latest received IP/port
+    ip_addr_t ip;
+    uint16_t  port;
+    // keep-alive interval in seconds, 0 is disable
+    uint16_t keepalive_interval;
+
+    struct wireguard_allowed_ip allowed_source_ips[kWgMaxSrcIPs];
+
+    uint8_t public_key[kWgPublicKeyLen];
+    uint8_t preshared_key[kWgSessionKeyLen];
+
+    // Precomputed DH(Sprivi,Spubr) with device private key, and peer public key
+    uint8_t public_key_dh[kWgPublicKeyLen];
+
+    // Session keypairs
+    struct wireguard_keypair curr_keypair;
+    struct wireguard_keypair prev_keypair;
+    struct wireguard_keypair next_keypair;
+
+    // 5.1 Silence is a Virtue: The responder keeps track of the greatest timestamp received per peer
+    uint8_t greatest_timestamp[kWgTai64Len];
+
+    // The active handshake that is happening
+    struct wireguard_handshake handshake;
+
+    // Decrypted cookie from the responder
+    uint32_t cookie_millis;
+    uint8_t  cookie[kWgCookieLen];
+
+    // The latest mac1 we sent with initiation
+    bool    handshake_mac1_valid;
+    uint8_t handshake_mac1[kWgCookieLen];
+
+    // Precomputed keys for use in mac validation
+    uint8_t label_cookie_key[kWgSessionKeyLen];
+    uint8_t label_mac1_key[kWgSessionKeyLen];
+
+    // The last time we received a valid initiation message
+    uint32_t last_initiation_rx;
+    // The last time we sent an initiation message to this peer
+    uint32_t last_initiation_tx;
+
+    // last_tx and last_rx of data packets
+    uint32_t last_tx;
+    uint32_t last_rx;
+
+    // We set this flag on RX/TX of packets if we think that we should initiate a new handshake
+    bool send_handshake;
+};
+
+struct wireguard_device
+{
+    // Maybe have a "Device private" member to abstract these?
+    struct netif   *netif;
+    struct udp_pcb *udp_pcb;
+
+    uint8_t public_key[kWgPublicKeyLen];
+    uint8_t private_key[kWgPrivateKeyLen];
+
+    uint8_t  cookie_secret[kWgHashLen];
+    uint32_t cookie_secret_millis;
+
+    // Precalculated
+    uint8_t label_cookie_key[kWgSessionKeyLen];
+    uint8_t label_mac1_key[kWgSessionKeyLen];
+
+    // List of peers associated with this device
+    struct wireguard_peer peers[kWgMaxPeers];
+
+    bool valid;
+};
+
+#define MESSAGE_INVALID              0
+#define MESSAGE_HANDSHAKE_INITIATION 1
+#define MESSAGE_HANDSHAKE_RESPONSE   2
+#define MESSAGE_COOKIE_REPLY         3
+#define MESSAGE_TRANSPORT_DATA       4
+
+// 5.4.2 First Message: Initiator to Responder
+struct message_handshake_initiation
+{
+    uint8_t  type;
+    uint8_t  reserved[3];
+    uint32_t sender;
+    uint8_t  ephemeral[32];
+    uint8_t  enc_static[32 + kWgAuthTagLen];
+    uint8_t  enc_timestamp[kWgTai64Len + kWgAuthTagLen];
+    uint8_t  mac1[kWgCookieLen];
+    uint8_t  mac2[kWgCookieLen];
+} __attribute__((__packed__));
+
+// 5.4.3 Second Message: Responder to Initiator
+struct message_handshake_response
+{
+    uint8_t  type;
+    uint8_t  reserved[3];
+    uint32_t sender;
+    uint32_t receiver;
+    uint8_t  ephemeral[32];
+    uint8_t  enc_empty[0 + kWgAuthTagLen];
+    uint8_t  mac1[kWgCookieLen];
+    uint8_t  mac2[kWgCookieLen];
+} __attribute__((__packed__));
+
+// 5.4.7 Under Load: Cookie Reply Message
+struct message_cookie_reply
+{
+    uint8_t  type;
+    uint8_t  reserved[3];
+    uint32_t receiver;
+    uint8_t  nonce[kWgCookieNonceLen];
+    uint8_t  enc_cookie[kWgCookieLen + kWgAuthTagLen];
+} __attribute__((__packed__));
+
+// 5.4.6 Subsequent Messages: Transport Data Messages
+struct message_transport_data
+{
+    uint8_t  type;
+    uint8_t  reserved[3];
+    uint32_t receiver;
+    uint8_t  counter[8];
+    // Followed by encrypted data
+    uint8_t enc_packet[];
+} __attribute__((__packed__));

tunnels/shared/wireguard/lwip-LICENSE.txt

@@ -0,0 +1,24 @@
+Copyright (c) 2001, 2002 Swedish Institute of Computer Science.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+3. The name of the author may not be used to endorse or promote products
+   derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+OF SUCH DAMAGE.

tunnels/shared/wireguard/wireguard-lwip-LICENSE.txt

@@ -0,0 +1,26 @@
+Copyright (c) 2021 Daniel Hope (www.floorsense.nz)
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+* Redistributions in binary form must reproduce the above copyright notice, this
+  list of conditions and the following disclaimer in the documentation and/or
+  other materials provided with the distribution.
+* Neither the name of "Floorsense Ltd", "Agile Workspace Ltd" nor the names of 
+  its contributors may be used to endorse or promote products derived from this
+  software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+Author: Daniel Hope <[email protected]>