LXR linux/drivers/net/wireguard/messages.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
   4 */
   5
   6#ifndef _WG_MESSAGES_H
   7#define _WG_MESSAGES_H
   8
   9#include <crypto/curve25519.h>
  10#include <crypto/chacha20poly1305.h>
  11#include <crypto/blake2s.h>
  12
  13#include <linux/kernel.h>
  14#include <linux/param.h>
  15#include <linux/skbuff.h>
  16
  17enum noise_lengths {
  18        NOISE_PUBLIC_KEY_LEN = CURVE25519_KEY_SIZE,
  19        NOISE_SYMMETRIC_KEY_LEN = CHACHA20POLY1305_KEY_SIZE,
  20        NOISE_TIMESTAMP_LEN = sizeof(u64) + sizeof(u32),
  21        NOISE_AUTHTAG_LEN = CHACHA20POLY1305_AUTHTAG_SIZE,
  22        NOISE_HASH_LEN = BLAKE2S_HASH_SIZE
  23};
  24
  25#define noise_encrypted_len(plain_len) ((plain_len) + NOISE_AUTHTAG_LEN)
  26
  27enum cookie_values {
  28        COOKIE_SECRET_MAX_AGE = 2 * 60,
  29        COOKIE_SECRET_LATENCY = 5,
  30        COOKIE_NONCE_LEN = XCHACHA20POLY1305_NONCE_SIZE,
  31        COOKIE_LEN = 16
  32};
  33
  34enum counter_values {
  35        COUNTER_BITS_TOTAL = 8192,
  36        COUNTER_REDUNDANT_BITS = BITS_PER_LONG,
  37        COUNTER_WINDOW_SIZE = COUNTER_BITS_TOTAL - COUNTER_REDUNDANT_BITS
  38};
  39
  40enum limits {
  41        REKEY_AFTER_MESSAGES = 1ULL << 60,
  42        REJECT_AFTER_MESSAGES = U64_MAX - COUNTER_WINDOW_SIZE - 1,
  43        REKEY_TIMEOUT = 5,
  44        REKEY_TIMEOUT_JITTER_MAX_JIFFIES = HZ / 3,
  45        REKEY_AFTER_TIME = 120,
  46        REJECT_AFTER_TIME = 180,
  47        INITIATIONS_PER_SECOND = 50,
  48        MAX_PEERS_PER_DEVICE = 1U << 20,
  49        KEEPALIVE_TIMEOUT = 10,
  50        MAX_TIMER_HANDSHAKES = 90 / REKEY_TIMEOUT,
  51        MAX_QUEUED_INCOMING_HANDSHAKES = 4096, /* TODO: replace this with DQL */
  52        MAX_STAGED_PACKETS = 128,
  53        MAX_QUEUED_PACKETS = 1024 /* TODO: replace this with DQL */
  54};
  55
  56enum message_type {
  57        MESSAGE_INVALID = 0,
  58        MESSAGE_HANDSHAKE_INITIATION = 1,
  59        MESSAGE_HANDSHAKE_RESPONSE = 2,
  60        MESSAGE_HANDSHAKE_COOKIE = 3,
  61        MESSAGE_DATA = 4
  62};
  63
  64struct message_header {
  65        /* The actual layout of this that we want is:
  66         * u8 type
  67         * u8 reserved_zero[3]
  68         *
  69         * But it turns out that by encoding this as little endian,
  70         * we achieve the same thing, and it makes checking faster.
  71         */
  72        __le32 type;
  73};
  74
  75struct message_macs {
  76        u8 mac1[COOKIE_LEN];
  77        u8 mac2[COOKIE_LEN];
  78};
  79
  80struct message_handshake_initiation {
  81        struct message_header header;
  82        __le32 sender_index;
  83        u8 unencrypted_ephemeral[NOISE_PUBLIC_KEY_LEN];
  84        u8 encrypted_static[noise_encrypted_len(NOISE_PUBLIC_KEY_LEN)];
  85        u8 encrypted_timestamp[noise_encrypted_len(NOISE_TIMESTAMP_LEN)];
  86        struct message_macs macs;
  87};
  88
  89struct message_handshake_response {
  90        struct message_header header;
  91        __le32 sender_index;
  92        __le32 receiver_index;
  93        u8 unencrypted_ephemeral[NOISE_PUBLIC_KEY_LEN];
  94        u8 encrypted_nothing[noise_encrypted_len(0)];
  95        struct message_macs macs;
  96};
  97
  98struct message_handshake_cookie {
  99        struct message_header header;
 100        __le32 receiver_index;
 101        u8 nonce[COOKIE_NONCE_LEN];
 102        u8 encrypted_cookie[noise_encrypted_len(COOKIE_LEN)];
 103};
 104
 105struct message_data {
 106        struct message_header header;
 107        __le32 key_idx;
 108        __le64 counter;
 109        u8 encrypted_data[];
 110};
 111
 112#define message_data_len(plain_len) \
 113        (noise_encrypted_len(plain_len) + sizeof(struct message_data))
 114
 115enum message_alignments {
 116        MESSAGE_PADDING_MULTIPLE = 16,
 117        MESSAGE_MINIMUM_LENGTH = message_data_len(0)
 118};
 119
 120#define SKB_HEADER_LEN                                       \
 121        (max(sizeof(struct iphdr), sizeof(struct ipv6hdr)) + \
 122         sizeof(struct udphdr) + NET_SKB_PAD)
 123#define DATA_PACKET_HEAD_ROOM \
 124        ALIGN(sizeof(struct message_data) + SKB_HEADER_LEN, 4)
 125
 126enum { HANDSHAKE_DSCP = 0x88 /* AF41, plus 00 ECN */ };
 127
 128#endif /* _WG_MESSAGES_H */
 129