/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*/
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#ifndef _WG_MESSAGES_H
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#define _WG_MESSAGES_H
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#include <crypto/curve25519.h>
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#include <crypto/chacha20poly1305.h>
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#include <crypto/blake2s.h>
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#include <linux/kernel.h>
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#include <linux/param.h>
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#include <linux/skbuff.h>
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enum noise_lengths {
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NOISE_PUBLIC_KEY_LEN = CURVE25519_KEY_SIZE,
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NOISE_SYMMETRIC_KEY_LEN = CHACHA20POLY1305_KEY_SIZE,
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NOISE_TIMESTAMP_LEN = sizeof(u64) + sizeof(u32),
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NOISE_AUTHTAG_LEN = CHACHA20POLY1305_AUTHTAG_SIZE,
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NOISE_HASH_LEN = BLAKE2S_HASH_SIZE
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};
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#define noise_encrypted_len(plain_len) ((plain_len) + NOISE_AUTHTAG_LEN)
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enum cookie_values {
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COOKIE_SECRET_MAX_AGE = 2 * 60,
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COOKIE_SECRET_LATENCY = 5,
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COOKIE_NONCE_LEN = XCHACHA20POLY1305_NONCE_SIZE,
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COOKIE_LEN = 16
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};
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enum counter_values {
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COUNTER_BITS_TOTAL = 8192,
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COUNTER_REDUNDANT_BITS = BITS_PER_LONG,
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COUNTER_WINDOW_SIZE = COUNTER_BITS_TOTAL - COUNTER_REDUNDANT_BITS
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};
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enum limits {
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REKEY_AFTER_MESSAGES = 1ULL << 60,
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REJECT_AFTER_MESSAGES = U64_MAX - COUNTER_WINDOW_SIZE - 1,
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REKEY_TIMEOUT = 5,
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REKEY_TIMEOUT_JITTER_MAX_JIFFIES = HZ / 3,
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REKEY_AFTER_TIME = 120,
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REJECT_AFTER_TIME = 180,
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INITIATIONS_PER_SECOND = 50,
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MAX_PEERS_PER_DEVICE = 1U << 20,
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KEEPALIVE_TIMEOUT = 10,
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MAX_TIMER_HANDSHAKES = 90 / REKEY_TIMEOUT,
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MAX_QUEUED_INCOMING_HANDSHAKES = 4096, /* TODO: replace this with DQL */
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MAX_STAGED_PACKETS = 128,
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MAX_QUEUED_PACKETS = 1024 /* TODO: replace this with DQL */
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};
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enum message_type {
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MESSAGE_INVALID = 0,
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MESSAGE_HANDSHAKE_INITIATION = 1,
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MESSAGE_HANDSHAKE_RESPONSE = 2,
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MESSAGE_HANDSHAKE_COOKIE = 3,
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MESSAGE_DATA = 4
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};
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struct message_header {
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/* The actual layout of this that we want is:
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* u8 type
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* u8 reserved_zero[3]
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*
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* But it turns out that by encoding this as little endian,
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* we achieve the same thing, and it makes checking faster.
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*/
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__le32 type;
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};
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struct message_macs {
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u8 mac1[COOKIE_LEN];
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u8 mac2[COOKIE_LEN];
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};
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struct message_handshake_initiation {
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struct message_header header;
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__le32 sender_index;
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u8 unencrypted_ephemeral[NOISE_PUBLIC_KEY_LEN];
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u8 encrypted_static[noise_encrypted_len(NOISE_PUBLIC_KEY_LEN)];
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u8 encrypted_timestamp[noise_encrypted_len(NOISE_TIMESTAMP_LEN)];
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struct message_macs macs;
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};
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struct message_handshake_response {
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struct message_header header;
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__le32 sender_index;
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__le32 receiver_index;
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u8 unencrypted_ephemeral[NOISE_PUBLIC_KEY_LEN];
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u8 encrypted_nothing[noise_encrypted_len(0)];
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struct message_macs macs;
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};
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struct message_handshake_cookie {
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struct message_header header;
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__le32 receiver_index;
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u8 nonce[COOKIE_NONCE_LEN];
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u8 encrypted_cookie[noise_encrypted_len(COOKIE_LEN)];
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};
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struct message_data {
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struct message_header header;
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__le32 key_idx;
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__le64 counter;
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u8 encrypted_data[];
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};
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#define message_data_len(plain_len) \
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(noise_encrypted_len(plain_len) + sizeof(struct message_data))
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enum message_alignments {
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MESSAGE_PADDING_MULTIPLE = 16,
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MESSAGE_MINIMUM_LENGTH = message_data_len(0)
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};
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#define SKB_HEADER_LEN \
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(max(sizeof(struct iphdr), sizeof(struct ipv6hdr)) + \
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sizeof(struct udphdr) + NET_SKB_PAD)
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#define DATA_PACKET_HEAD_ROOM \
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ALIGN(sizeof(struct message_data) + SKB_HEADER_LEN, 4)
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enum { HANDSHAKE_DSCP = 0x88 /* AF41, plus 00 ECN */ };
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#endif /* _WG_MESSAGES_H */
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