This change implements encryption/decryption and encapsulation/decapsulation of OpenVPN packets.
Support for generic crypto state is added along with a wrapper for the AEAD crypto kernel API.
Signed-off-by: Antonio Quartulli antonio@openvpn.net --- drivers/net/ovpn/Makefile | 3 + drivers/net/ovpn/crypto.c | 153 ++++++++++++++++++ drivers/net/ovpn/crypto.h | 136 ++++++++++++++++ drivers/net/ovpn/crypto_aead.c | 354 +++++++++++++++++++++++++++++++++++++++++ drivers/net/ovpn/crypto_aead.h | 31 ++++ drivers/net/ovpn/io.c | 140 ++++++++++++++-- drivers/net/ovpn/io.h | 3 + drivers/net/ovpn/packet.h | 2 +- drivers/net/ovpn/peer.c | 29 ++++ drivers/net/ovpn/peer.h | 6 + drivers/net/ovpn/pktid.c | 130 +++++++++++++++ drivers/net/ovpn/pktid.h | 87 ++++++++++ drivers/net/ovpn/proto.h | 31 ++++ drivers/net/ovpn/skb.h | 11 +- 14 files changed, 1104 insertions(+), 12 deletions(-)
diff --git a/drivers/net/ovpn/Makefile b/drivers/net/ovpn/Makefile index 56bddc9bef83e0befde6af3c3565bb91731d7b22..ccdaeced1982c851475657860a005ff2b9dfbd13 100644 --- a/drivers/net/ovpn/Makefile +++ b/drivers/net/ovpn/Makefile @@ -8,10 +8,13 @@
obj-$(CONFIG_OVPN) := ovpn.o ovpn-y += bind.o +ovpn-y += crypto.o +ovpn-y += crypto_aead.o ovpn-y += main.o ovpn-y += io.o ovpn-y += netlink.o ovpn-y += netlink-gen.o ovpn-y += peer.o +ovpn-y += pktid.o ovpn-y += socket.o ovpn-y += udp.o diff --git a/drivers/net/ovpn/crypto.c b/drivers/net/ovpn/crypto.c new file mode 100644 index 0000000000000000000000000000000000000000..f1f7510e2f735e367f96eb4982ba82c9af3c8bfc --- /dev/null +++ b/drivers/net/ovpn/crypto.c @@ -0,0 +1,153 @@ +// SPDX-License-Identifier: GPL-2.0 +/* OpenVPN data channel offload + * + * Copyright (C) 2020-2024 OpenVPN, Inc. + * + * Author: James Yonan james@openvpn.net + * Antonio Quartulli antonio@openvpn.net + */ + +#include <linux/types.h> +#include <linux/net.h> +#include <linux/netdevice.h> +#include <uapi/linux/ovpn.h> + +#include "ovpnstruct.h" +#include "main.h" +#include "packet.h" +#include "pktid.h" +#include "crypto_aead.h" +#include "crypto.h" + +static void ovpn_ks_destroy_rcu(struct rcu_head *head) +{ + struct ovpn_crypto_key_slot *ks; + + ks = container_of(head, struct ovpn_crypto_key_slot, rcu); + ovpn_aead_crypto_key_slot_destroy(ks); +} + +void ovpn_crypto_key_slot_release(struct kref *kref) +{ + struct ovpn_crypto_key_slot *ks; + + ks = container_of(kref, struct ovpn_crypto_key_slot, refcount); + call_rcu(&ks->rcu, ovpn_ks_destroy_rcu); +} + +/* can only be invoked when all peer references have been dropped (i.e. RCU + * release routine) + */ +void ovpn_crypto_state_release(struct ovpn_crypto_state *cs) +{ + struct ovpn_crypto_key_slot *ks; + + ks = rcu_access_pointer(cs->slots[0]); + if (ks) { + RCU_INIT_POINTER(cs->slots[0], NULL); + ovpn_crypto_key_slot_put(ks); + } + + ks = rcu_access_pointer(cs->slots[1]); + if (ks) { + RCU_INIT_POINTER(cs->slots[1], NULL); + ovpn_crypto_key_slot_put(ks); + } +} + +/* Reset the ovpn_crypto_state object in a way that is atomic + * to RCU readers. + */ +int ovpn_crypto_state_reset(struct ovpn_crypto_state *cs, + const struct ovpn_peer_key_reset *pkr) +{ + struct ovpn_crypto_key_slot *old = NULL, *new; + u8 idx; + + if (pkr->slot != OVPN_KEY_SLOT_PRIMARY && + pkr->slot != OVPN_KEY_SLOT_SECONDARY) + return -EINVAL; + + new = ovpn_aead_crypto_key_slot_new(&pkr->key); + if (IS_ERR(new)) + return PTR_ERR(new); + + spin_lock_bh(&cs->lock); + idx = cs->primary_idx; + switch (pkr->slot) { + case OVPN_KEY_SLOT_PRIMARY: + old = rcu_replace_pointer(cs->slots[idx], new, + lockdep_is_held(&cs->lock)); + break; + case OVPN_KEY_SLOT_SECONDARY: + old = rcu_replace_pointer(cs->slots[!idx], new, + lockdep_is_held(&cs->lock)); + break; + } + spin_unlock_bh(&cs->lock); + + if (old) + ovpn_crypto_key_slot_put(old); + + return 0; +} + +void ovpn_crypto_key_slot_delete(struct ovpn_crypto_state *cs, + enum ovpn_key_slot slot) +{ + struct ovpn_crypto_key_slot *ks = NULL; + u8 idx; + + if (slot != OVPN_KEY_SLOT_PRIMARY && + slot != OVPN_KEY_SLOT_SECONDARY) { + pr_warn("Invalid slot to release: %u\n", slot); + return; + } + + spin_lock_bh(&cs->lock); + idx = cs->primary_idx; + switch (slot) { + case OVPN_KEY_SLOT_PRIMARY: + ks = rcu_replace_pointer(cs->slots[idx], NULL, + lockdep_is_held(&cs->lock)); + break; + case OVPN_KEY_SLOT_SECONDARY: + ks = rcu_replace_pointer(cs->slots[!idx], NULL, + lockdep_is_held(&cs->lock)); + break; + } + spin_unlock_bh(&cs->lock); + + if (!ks) { + pr_debug("Key slot already released: %u\n", slot); + return; + } + + pr_debug("deleting key slot %u, key_id=%u\n", slot, ks->key_id); + ovpn_crypto_key_slot_put(ks); +} + +/* this swap is not atomic, but there will be a very short time frame where the + * old_secondary key won't be available. This should not be a big deal as most + * likely both peers are already using the new primary at this point. + */ +void ovpn_crypto_key_slots_swap(struct ovpn_crypto_state *cs) +{ + const struct ovpn_crypto_key_slot *old_primary, *old_secondary; + u8 idx; + + spin_lock_bh(&cs->lock); + idx = cs->primary_idx; + old_primary = rcu_dereference_protected(cs->slots[idx], + lockdep_is_held(&cs->lock)); + old_secondary = rcu_dereference_protected(cs->slots[!idx], + lockdep_is_held(&cs->lock)); + /* perform real swap by switching the index of the primary key */ + cs->primary_idx = !cs->primary_idx; + + pr_debug("key swapped: (old primary) %d <-> (new primary) %d\n", + old_primary ? old_primary->key_id : -1, + old_secondary ? old_secondary->key_id : -1); + + spin_unlock_bh(&cs->lock); +} diff --git a/drivers/net/ovpn/crypto.h b/drivers/net/ovpn/crypto.h new file mode 100644 index 0000000000000000000000000000000000000000..61de855d23649598a6e5a34447a35ed9620dfde1 --- /dev/null +++ b/drivers/net/ovpn/crypto.h @@ -0,0 +1,136 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* OpenVPN data channel offload + * + * Copyright (C) 2020-2024 OpenVPN, Inc. + * + * Author: James Yonan james@openvpn.net + * Antonio Quartulli antonio@openvpn.net + */ + +#ifndef _NET_OVPN_OVPNCRYPTO_H_ +#define _NET_OVPN_OVPNCRYPTO_H_ + +/* info needed for both encrypt and decrypt directions */ +struct ovpn_key_direction { + const u8 *cipher_key; + size_t cipher_key_size; + const u8 *nonce_tail; /* only needed for GCM modes */ + size_t nonce_tail_size; /* only needed for GCM modes */ +}; + +/* all info for a particular symmetric key (primary or secondary) */ +struct ovpn_key_config { + enum ovpn_cipher_alg cipher_alg; + u8 key_id; + struct ovpn_key_direction encrypt; + struct ovpn_key_direction decrypt; +}; + +/* used to pass settings from netlink to the crypto engine */ +struct ovpn_peer_key_reset { + enum ovpn_key_slot slot; + struct ovpn_key_config key; +}; + +struct ovpn_crypto_key_slot { + u8 key_id; + + struct crypto_aead *encrypt; + struct crypto_aead *decrypt; + struct ovpn_nonce_tail nonce_tail_xmit; + struct ovpn_nonce_tail nonce_tail_recv; + + struct ovpn_pktid_recv pid_recv ____cacheline_aligned_in_smp; + struct ovpn_pktid_xmit pid_xmit ____cacheline_aligned_in_smp; + struct kref refcount; + struct rcu_head rcu; +}; + +struct ovpn_crypto_state { + struct ovpn_crypto_key_slot __rcu *slots[2]; + u8 primary_idx; + + /* protects primary and secondary slots */ + spinlock_t lock; +}; + +static inline bool ovpn_crypto_key_slot_hold(struct ovpn_crypto_key_slot *ks) +{ + return kref_get_unless_zero(&ks->refcount); +} + +static inline void ovpn_crypto_state_init(struct ovpn_crypto_state *cs) +{ + RCU_INIT_POINTER(cs->slots[0], NULL); + RCU_INIT_POINTER(cs->slots[1], NULL); + cs->primary_idx = 0; + spin_lock_init(&cs->lock); +} + +static inline struct ovpn_crypto_key_slot * +ovpn_crypto_key_id_to_slot(const struct ovpn_crypto_state *cs, u8 key_id) +{ + struct ovpn_crypto_key_slot *ks; + u8 idx; + + if (unlikely(!cs)) + return NULL; + + rcu_read_lock(); + idx = cs->primary_idx; + ks = rcu_dereference(cs->slots[idx]); + if (ks && ks->key_id == key_id) { + if (unlikely(!ovpn_crypto_key_slot_hold(ks))) + ks = NULL; + goto out; + } + + ks = rcu_dereference(cs->slots[idx ^ 1]); + if (ks && ks->key_id == key_id) { + if (unlikely(!ovpn_crypto_key_slot_hold(ks))) + ks = NULL; + goto out; + } + + /* when both key slots are occupied but no matching key ID is found, ks + * has to be reset to NULL to avoid carrying a stale pointer + */ + ks = NULL; +out: + rcu_read_unlock(); + + return ks; +} + +static inline struct ovpn_crypto_key_slot * +ovpn_crypto_key_slot_primary(const struct ovpn_crypto_state *cs) +{ + struct ovpn_crypto_key_slot *ks; + + rcu_read_lock(); + ks = rcu_dereference(cs->slots[cs->primary_idx]); + if (unlikely(ks && !ovpn_crypto_key_slot_hold(ks))) + ks = NULL; + rcu_read_unlock(); + + return ks; +} + +void ovpn_crypto_key_slot_release(struct kref *kref); + +static inline void ovpn_crypto_key_slot_put(struct ovpn_crypto_key_slot *ks) +{ + kref_put(&ks->refcount, ovpn_crypto_key_slot_release); +} + +int ovpn_crypto_state_reset(struct ovpn_crypto_state *cs, + const struct ovpn_peer_key_reset *pkr); + +void ovpn_crypto_key_slot_delete(struct ovpn_crypto_state *cs, + enum ovpn_key_slot slot); + +void ovpn_crypto_state_release(struct ovpn_crypto_state *cs); + +void ovpn_crypto_key_slots_swap(struct ovpn_crypto_state *cs); + +#endif /* _NET_OVPN_OVPNCRYPTO_H_ */ diff --git a/drivers/net/ovpn/crypto_aead.c b/drivers/net/ovpn/crypto_aead.c new file mode 100644 index 0000000000000000000000000000000000000000..97134ac679c67a3d44a0bf49c2ddf058fd7c0e99 --- /dev/null +++ b/drivers/net/ovpn/crypto_aead.c @@ -0,0 +1,354 @@ +// SPDX-License-Identifier: GPL-2.0 +/* OpenVPN data channel offload + * + * Copyright (C) 2020-2024 OpenVPN, Inc. + * + * Author: James Yonan james@openvpn.net + * Antonio Quartulli antonio@openvpn.net + */ + +#include <crypto/aead.h> +#include <linux/skbuff.h> +#include <net/ip.h> +#include <net/ipv6.h> +#include <net/udp.h> + +#include "ovpnstruct.h" +#include "main.h" +#include "io.h" +#include "packet.h" +#include "pktid.h" +#include "crypto_aead.h" +#include "crypto.h" +#include "peer.h" +#include "proto.h" +#include "skb.h" + +#define AUTH_TAG_SIZE 16 + +static int ovpn_aead_encap_overhead(const struct ovpn_crypto_key_slot *ks) +{ + return OVPN_OP_SIZE_V2 + /* OP header size */ + 4 + /* Packet ID */ + crypto_aead_authsize(ks->encrypt); /* Auth Tag */ +} + +int ovpn_aead_encrypt(struct ovpn_peer *peer, struct ovpn_crypto_key_slot *ks, + struct sk_buff *skb) +{ + const unsigned int tag_size = crypto_aead_authsize(ks->encrypt); + const unsigned int head_size = ovpn_aead_encap_overhead(ks); + struct aead_request *req; + struct sk_buff *trailer; + struct scatterlist *sg; + u8 iv[NONCE_SIZE]; + int nfrags, ret; + u32 pktid, op; + + /* Sample AEAD header format: + * 48000001 00000005 7e7046bd 444a7e28 cc6387b1 64a4d6c1 380275a... + * [ OP32 ] [seq # ] [ auth tag ] [ payload ... ] + * [4-byte + * IV head] + */ + + /* check that there's enough headroom in the skb for packet + * encapsulation, after adding network header and encryption overhead + */ + if (unlikely(skb_cow_head(skb, OVPN_HEAD_ROOM + head_size))) + return -ENOBUFS; + + /* get number of skb frags and ensure that packet data is writable */ + nfrags = skb_cow_data(skb, 0, &trailer); + if (unlikely(nfrags < 0)) + return nfrags; + + if (unlikely(nfrags + 2 > (MAX_SKB_FRAGS + 2))) + return -ENOSPC; + + ovpn_skb_cb(skb)->ctx = kmalloc(sizeof(*ovpn_skb_cb(skb)->ctx), + GFP_ATOMIC); + if (unlikely(!ovpn_skb_cb(skb)->ctx)) + return -ENOMEM; + + sg = ovpn_skb_cb(skb)->ctx->sg; + + /* sg table: + * 0: op, wire nonce (AD, len=OVPN_OP_SIZE_V2+NONCE_WIRE_SIZE), + * 1, 2, 3, ..., n: payload, + * n+1: auth_tag (len=tag_size) + */ + sg_init_table(sg, nfrags + 2); + + /* build scatterlist to encrypt packet payload */ + ret = skb_to_sgvec_nomark(skb, sg + 1, 0, skb->len); + if (unlikely(nfrags != ret)) + return -EINVAL; + + /* append auth_tag onto scatterlist */ + __skb_push(skb, tag_size); + sg_set_buf(sg + nfrags + 1, skb->data, tag_size); + + /* obtain packet ID, which is used both as a first + * 4 bytes of nonce and last 4 bytes of associated data. + */ + ret = ovpn_pktid_xmit_next(&ks->pid_xmit, &pktid); + if (unlikely(ret < 0)) { + kfree(ovpn_skb_cb(skb)->ctx); + return ret; + } + + /* concat 4 bytes packet id and 8 bytes nonce tail into 12 bytes + * nonce + */ + ovpn_pktid_aead_write(pktid, &ks->nonce_tail_xmit, iv); + + /* make space for packet id and push it to the front */ + __skb_push(skb, NONCE_WIRE_SIZE); + memcpy(skb->data, iv, NONCE_WIRE_SIZE); + + /* add packet op as head of additional data */ + op = ovpn_opcode_compose(OVPN_DATA_V2, ks->key_id, peer->id); + __skb_push(skb, OVPN_OP_SIZE_V2); + BUILD_BUG_ON(sizeof(op) != OVPN_OP_SIZE_V2); + *((__force __be32 *)skb->data) = htonl(op); + + /* AEAD Additional data */ + sg_set_buf(sg, skb->data, OVPN_OP_SIZE_V2 + NONCE_WIRE_SIZE); + + req = aead_request_alloc(ks->encrypt, GFP_ATOMIC); + if (unlikely(!req)) { + kfree(ovpn_skb_cb(skb)->ctx); + return -ENOMEM; + } + + /* setup async crypto operation */ + aead_request_set_tfm(req, ks->encrypt); + aead_request_set_callback(req, 0, ovpn_encrypt_post, skb); + aead_request_set_crypt(req, sg, sg, skb->len - head_size, iv); + aead_request_set_ad(req, OVPN_OP_SIZE_V2 + NONCE_WIRE_SIZE); + + ovpn_skb_cb(skb)->ctx->peer = peer; + ovpn_skb_cb(skb)->ctx->req = req; + ovpn_skb_cb(skb)->ctx->ks = ks; + + /* encrypt it */ + return crypto_aead_encrypt(req); +} + +int ovpn_aead_decrypt(struct ovpn_peer *peer, struct ovpn_crypto_key_slot *ks, + struct sk_buff *skb) +{ + const unsigned int tag_size = crypto_aead_authsize(ks->decrypt); + int ret, payload_len, nfrags; + unsigned int payload_offset; + struct aead_request *req; + struct sk_buff *trailer; + struct scatterlist *sg; + unsigned int sg_len; + u8 iv[NONCE_SIZE]; + + payload_offset = OVPN_OP_SIZE_V2 + NONCE_WIRE_SIZE + tag_size; + payload_len = skb->len - payload_offset; + + /* sanity check on packet size, payload size must be >= 0 */ + if (unlikely(payload_len < 0)) + return -EINVAL; + + /* Prepare the skb data buffer to be accessed up until the auth tag. + * This is required because this area is directly mapped into the sg + * list. + */ + if (unlikely(!pskb_may_pull(skb, payload_offset))) + return -ENODATA; + + /* get number of skb frags and ensure that packet data is writable */ + nfrags = skb_cow_data(skb, 0, &trailer); + if (unlikely(nfrags < 0)) + return nfrags; + + if (unlikely(nfrags + 2 > (MAX_SKB_FRAGS + 2))) + return -ENOSPC; + + ovpn_skb_cb(skb)->ctx = kmalloc(sizeof(*ovpn_skb_cb(skb)->ctx), + GFP_ATOMIC); + if (unlikely(!ovpn_skb_cb(skb)->ctx)) + return -ENOMEM; + + sg = ovpn_skb_cb(skb)->ctx->sg; + + /* sg table: + * 0: op, wire nonce (AD, len=OVPN_OP_SIZE_V2+NONCE_WIRE_SIZE), + * 1, 2, 3, ..., n: payload, + * n+1: auth_tag (len=tag_size) + */ + sg_init_table(sg, nfrags + 2); + + /* packet op is head of additional data */ + sg_len = OVPN_OP_SIZE_V2 + NONCE_WIRE_SIZE; + sg_set_buf(sg, skb->data, sg_len); + + /* build scatterlist to decrypt packet payload */ + ret = skb_to_sgvec_nomark(skb, sg + 1, payload_offset, payload_len); + if (unlikely(nfrags != ret)) { + kfree(ovpn_skb_cb(skb)->ctx); + return -EINVAL; + } + + /* append auth_tag onto scatterlist */ + sg_set_buf(sg + nfrags + 1, skb->data + sg_len, tag_size); + + /* copy nonce into IV buffer */ + memcpy(iv, skb->data + OVPN_OP_SIZE_V2, NONCE_WIRE_SIZE); + memcpy(iv + NONCE_WIRE_SIZE, ks->nonce_tail_recv.u8, + sizeof(struct ovpn_nonce_tail)); + + req = aead_request_alloc(ks->decrypt, GFP_ATOMIC); + if (unlikely(!req)) { + kfree(ovpn_skb_cb(skb)->ctx); + return -ENOMEM; + } + + /* setup async crypto operation */ + aead_request_set_tfm(req, ks->decrypt); + aead_request_set_callback(req, 0, ovpn_decrypt_post, skb); + aead_request_set_crypt(req, sg, sg, payload_len + tag_size, iv); + + aead_request_set_ad(req, NONCE_WIRE_SIZE + OVPN_OP_SIZE_V2); + + ovpn_skb_cb(skb)->ctx->payload_offset = payload_offset; + ovpn_skb_cb(skb)->ctx->peer = peer; + ovpn_skb_cb(skb)->ctx->req = req; + ovpn_skb_cb(skb)->ctx->ks = ks; + + /* decrypt it */ + return crypto_aead_decrypt(req); +} + +/* Initialize a struct crypto_aead object */ +struct crypto_aead *ovpn_aead_init(const char *title, const char *alg_name, + const unsigned char *key, + unsigned int keylen) +{ + struct crypto_aead *aead; + int ret; + + aead = crypto_alloc_aead(alg_name, 0, 0); + if (IS_ERR(aead)) { + ret = PTR_ERR(aead); + pr_err("%s crypto_alloc_aead failed, err=%d\n", title, ret); + aead = NULL; + goto error; + } + + ret = crypto_aead_setkey(aead, key, keylen); + if (ret) { + pr_err("%s crypto_aead_setkey size=%u failed, err=%d\n", title, + keylen, ret); + goto error; + } + + ret = crypto_aead_setauthsize(aead, AUTH_TAG_SIZE); + if (ret) { + pr_err("%s crypto_aead_setauthsize failed, err=%d\n", title, + ret); + goto error; + } + + /* basic AEAD assumption */ + if (crypto_aead_ivsize(aead) != NONCE_SIZE) { + pr_err("%s IV size must be %d\n", title, NONCE_SIZE); + ret = -EINVAL; + goto error; + } + + pr_debug("********* Cipher %s (%s)\n", alg_name, title); + pr_debug("*** IV size=%u\n", crypto_aead_ivsize(aead)); + pr_debug("*** req size=%u\n", crypto_aead_reqsize(aead)); + pr_debug("*** block size=%u\n", crypto_aead_blocksize(aead)); + pr_debug("*** auth size=%u\n", crypto_aead_authsize(aead)); + pr_debug("*** alignmask=0x%x\n", crypto_aead_alignmask(aead)); + + return aead; + +error: + crypto_free_aead(aead); + return ERR_PTR(ret); +} + +void ovpn_aead_crypto_key_slot_destroy(struct ovpn_crypto_key_slot *ks) +{ + if (!ks) + return; + + crypto_free_aead(ks->encrypt); + crypto_free_aead(ks->decrypt); + kfree(ks); +} + +struct ovpn_crypto_key_slot * +ovpn_aead_crypto_key_slot_new(const struct ovpn_key_config *kc) +{ + struct ovpn_crypto_key_slot *ks = NULL; + const char *alg_name; + int ret; + + /* validate crypto alg */ + switch (kc->cipher_alg) { + case OVPN_CIPHER_ALG_AES_GCM: + alg_name = "gcm(aes)"; + break; + case OVPN_CIPHER_ALG_CHACHA20_POLY1305: + alg_name = "rfc7539(chacha20,poly1305)"; + break; + default: + return ERR_PTR(-EOPNOTSUPP); + } + + if (sizeof(struct ovpn_nonce_tail) != kc->encrypt.nonce_tail_size || + sizeof(struct ovpn_nonce_tail) != kc->decrypt.nonce_tail_size) + return ERR_PTR(-EINVAL); + + /* build the key slot */ + ks = kmalloc(sizeof(*ks), GFP_KERNEL); + if (!ks) + return ERR_PTR(-ENOMEM); + + ks->encrypt = NULL; + ks->decrypt = NULL; + kref_init(&ks->refcount); + ks->key_id = kc->key_id; + + ks->encrypt = ovpn_aead_init("encrypt", alg_name, + kc->encrypt.cipher_key, + kc->encrypt.cipher_key_size); + if (IS_ERR(ks->encrypt)) { + ret = PTR_ERR(ks->encrypt); + ks->encrypt = NULL; + goto destroy_ks; + } + + ks->decrypt = ovpn_aead_init("decrypt", alg_name, + kc->decrypt.cipher_key, + kc->decrypt.cipher_key_size); + if (IS_ERR(ks->decrypt)) { + ret = PTR_ERR(ks->decrypt); + ks->decrypt = NULL; + goto destroy_ks; + } + + memcpy(ks->nonce_tail_xmit.u8, kc->encrypt.nonce_tail, + sizeof(struct ovpn_nonce_tail)); + memcpy(ks->nonce_tail_recv.u8, kc->decrypt.nonce_tail, + sizeof(struct ovpn_nonce_tail)); + + /* init packet ID generation/validation */ + ovpn_pktid_xmit_init(&ks->pid_xmit); + ovpn_pktid_recv_init(&ks->pid_recv); + + return ks; + +destroy_ks: + ovpn_aead_crypto_key_slot_destroy(ks); + return ERR_PTR(ret); +} diff --git a/drivers/net/ovpn/crypto_aead.h b/drivers/net/ovpn/crypto_aead.h new file mode 100644 index 0000000000000000000000000000000000000000..77ee8141599bc06b0dc664c5b0a4dae660a89238 --- /dev/null +++ b/drivers/net/ovpn/crypto_aead.h @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* OpenVPN data channel offload + * + * Copyright (C) 2020-2024 OpenVPN, Inc. + * + * Author: James Yonan james@openvpn.net + * Antonio Quartulli antonio@openvpn.net + */ + +#ifndef _NET_OVPN_OVPNAEAD_H_ +#define _NET_OVPN_OVPNAEAD_H_ + +#include "crypto.h" + +#include <asm/types.h> +#include <linux/skbuff.h> + +struct crypto_aead *ovpn_aead_init(const char *title, const char *alg_name, + const unsigned char *key, + unsigned int keylen); + +int ovpn_aead_encrypt(struct ovpn_peer *peer, struct ovpn_crypto_key_slot *ks, + struct sk_buff *skb); +int ovpn_aead_decrypt(struct ovpn_peer *peer, struct ovpn_crypto_key_slot *ks, + struct sk_buff *skb); + +struct ovpn_crypto_key_slot * +ovpn_aead_crypto_key_slot_new(const struct ovpn_key_config *kc); +void ovpn_aead_crypto_key_slot_destroy(struct ovpn_crypto_key_slot *ks); + +#endif /* _NET_OVPN_OVPNAEAD_H_ */ diff --git a/drivers/net/ovpn/io.c b/drivers/net/ovpn/io.c index 78449b52a2f8f710107d2493299c6aca9a2cb2ce..a75aa301b99e6abff04d5cb289b26b5979906ae5 100644 --- a/drivers/net/ovpn/io.c +++ b/drivers/net/ovpn/io.c @@ -7,6 +7,7 @@ * Antonio Quartulli antonio@openvpn.net */
+#include <crypto/aead.h> #include <linux/netdevice.h> #include <linux/skbuff.h> #include <net/gro_cells.h> @@ -15,6 +16,8 @@ #include "ovpnstruct.h" #include "peer.h" #include "io.h" +#include "crypto.h" +#include "crypto_aead.h" #include "netlink.h" #include "proto.h" #include "udp.h" @@ -57,33 +60,133 @@ static void ovpn_netdev_write(struct ovpn_peer *peer, struct sk_buff *skb) dev_sw_netstats_rx_add(peer->ovpn->dev, pkt_len); }
-static void ovpn_decrypt_post(struct sk_buff *skb, int ret) +void ovpn_decrypt_post(void *data, int ret) { - struct ovpn_peer *peer = ovpn_skb_cb(skb)->peer; + struct ovpn_crypto_key_slot *ks = NULL; + unsigned int payload_offset = 0; + struct ovpn_peer *peer = NULL; + struct sk_buff *skb = data; + __be16 proto; + __be32 *pid; + + /* crypto is happening asynchronously. this function will be called + * again later by the crypto callback with a proper return code + */ + if (unlikely(ret == -EINPROGRESS)) + return; + + /* crypto is done, cleanup skb CB and its members */ + if (likely(ovpn_skb_cb(skb)->ctx)) { + payload_offset = ovpn_skb_cb(skb)->ctx->payload_offset; + ks = ovpn_skb_cb(skb)->ctx->ks; + peer = ovpn_skb_cb(skb)->ctx->peer; + + aead_request_free(ovpn_skb_cb(skb)->ctx->req); + kfree(ovpn_skb_cb(skb)->ctx); + ovpn_skb_cb(skb)->ctx = NULL; + }
if (unlikely(ret < 0)) goto drop;
+ /* PID sits after the op */ + pid = (__force __be32 *)(skb->data + OVPN_OP_SIZE_V2); + ret = ovpn_pktid_recv(&ks->pid_recv, ntohl(*pid), 0); + if (unlikely(ret < 0)) { + net_err_ratelimited("%s: PKT ID RX error: %d\n", + peer->ovpn->dev->name, ret); + goto drop; + } + + /* point to encapsulated IP packet */ + __skb_pull(skb, payload_offset); + + /* check if this is a valid datapacket that has to be delivered to the + * ovpn interface + */ + skb_reset_network_header(skb); + proto = ovpn_ip_check_protocol(skb); + if (unlikely(!proto)) { + /* check if null packet */ + if (unlikely(!pskb_may_pull(skb, 1))) { + net_info_ratelimited("%s: NULL packet received from peer %u\n", + peer->ovpn->dev->name, peer->id); + goto drop; + } + + net_info_ratelimited("%s: unsupported protocol received from peer %u\n", + peer->ovpn->dev->name, peer->id); + goto drop; + } + skb->protocol = proto; + + /* perform Reverse Path Filtering (RPF) */ + if (unlikely(!ovpn_peer_check_by_src(peer->ovpn, skb, peer))) { + if (skb_protocol_to_family(skb) == AF_INET6) + net_dbg_ratelimited("%s: RPF dropped packet from peer %u, src: %pI6c\n", + peer->ovpn->dev->name, peer->id, + &ipv6_hdr(skb)->saddr); + else + net_dbg_ratelimited("%s: RPF dropped packet from peer %u, src: %pI4\n", + peer->ovpn->dev->name, peer->id, + &ip_hdr(skb)->saddr); + goto drop; + } + ovpn_netdev_write(peer, skb); /* skb is passed to upper layer - don't free it */ skb = NULL; drop: if (unlikely(skb)) dev_core_stats_rx_dropped_inc(peer->ovpn->dev); - ovpn_peer_put(peer); + if (likely(peer)) + ovpn_peer_put(peer); + if (likely(ks)) + ovpn_crypto_key_slot_put(ks); kfree_skb(skb); }
/* pick next packet from RX queue, decrypt and forward it to the device */ void ovpn_recv(struct ovpn_peer *peer, struct sk_buff *skb) { - ovpn_skb_cb(skb)->peer = peer; - ovpn_decrypt_post(skb, 0); + struct ovpn_crypto_key_slot *ks; + u8 key_id; + + /* get the key slot matching the key ID in the received packet */ + key_id = ovpn_key_id_from_skb(skb); + ks = ovpn_crypto_key_id_to_slot(&peer->crypto, key_id); + if (unlikely(!ks)) { + net_info_ratelimited("%s: no available key for peer %u, key-id: %u\n", + peer->ovpn->dev->name, peer->id, key_id); + dev_core_stats_rx_dropped_inc(peer->ovpn->dev); + kfree_skb(skb); + return; + } + + ovpn_skb_cb(skb)->ctx = NULL; + ovpn_decrypt_post(skb, ovpn_aead_decrypt(peer, ks, skb)); }
-static void ovpn_encrypt_post(struct sk_buff *skb, int ret) +void ovpn_encrypt_post(void *data, int ret) { - struct ovpn_peer *peer = ovpn_skb_cb(skb)->peer; + struct ovpn_peer *peer = NULL; + struct sk_buff *skb = data; + + /* encryption is happening asynchronously. This function will be + * called later by the crypto callback with a proper return value + */ + if (unlikely(ret == -EINPROGRESS)) + return; + + /* crypto is done, cleanup skb CB and its members */ + if (likely(ovpn_skb_cb(skb)->ctx)) { + peer = ovpn_skb_cb(skb)->ctx->peer; + + ovpn_crypto_key_slot_put(ovpn_skb_cb(skb)->ctx->ks); + aead_request_free(ovpn_skb_cb(skb)->ctx->req); + kfree(ovpn_skb_cb(skb)->ctx); + ovpn_skb_cb(skb)->ctx = NULL; + }
if (unlikely(ret < 0)) goto err; @@ -103,13 +206,29 @@ static void ovpn_encrypt_post(struct sk_buff *skb, int ret) err: if (unlikely(skb)) dev_core_stats_tx_dropped_inc(peer->ovpn->dev); - ovpn_peer_put(peer); + if (likely(peer)) + ovpn_peer_put(peer); kfree_skb(skb); }
static bool ovpn_encrypt_one(struct ovpn_peer *peer, struct sk_buff *skb) { - ovpn_skb_cb(skb)->peer = peer; + struct ovpn_crypto_key_slot *ks; + + if (unlikely(skb->ip_summed == CHECKSUM_PARTIAL && + skb_checksum_help(skb))) { + net_warn_ratelimited("%s: cannot compute checksum for outgoing packet\n", + peer->ovpn->dev->name); + return false; + } + + /* get primary key to be used for encrypting data */ + ks = ovpn_crypto_key_slot_primary(&peer->crypto); + if (unlikely(!ks)) { + net_warn_ratelimited("%s: error while retrieving primary key slot for peer %u\n", + peer->ovpn->dev->name, peer->id); + return false; + }
/* take a reference to the peer because the crypto code may run async. * ovpn_encrypt_post() will release it upon completion @@ -119,7 +238,8 @@ static bool ovpn_encrypt_one(struct ovpn_peer *peer, struct sk_buff *skb) return false; }
- ovpn_encrypt_post(skb, 0); + ovpn_skb_cb(skb)->ctx = NULL; + ovpn_encrypt_post(skb, ovpn_aead_encrypt(peer, ks, skb)); return true; }
diff --git a/drivers/net/ovpn/io.h b/drivers/net/ovpn/io.h index 9667a0a470e0b4b427524fffb5b9b395007e5a2f..ad81dd86924689309b3299573575a1705eddaf99 100644 --- a/drivers/net/ovpn/io.h +++ b/drivers/net/ovpn/io.h @@ -14,4 +14,7 @@ netdev_tx_t ovpn_net_xmit(struct sk_buff *skb, struct net_device *dev);
void ovpn_recv(struct ovpn_peer *peer, struct sk_buff *skb);
+void ovpn_encrypt_post(void *data, int ret); +void ovpn_decrypt_post(void *data, int ret); + #endif /* _NET_OVPN_OVPN_H_ */ diff --git a/drivers/net/ovpn/packet.h b/drivers/net/ovpn/packet.h index 7ed146f5932a25f448af6da58738a7eae81007fe..e14c9bf464f742e6d27fe3133dd175996970845e 100644 --- a/drivers/net/ovpn/packet.h +++ b/drivers/net/ovpn/packet.h @@ -10,7 +10,7 @@ #ifndef _NET_OVPN_PACKET_H_ #define _NET_OVPN_PACKET_H_
-/* When the OpenVPN protocol is ran in AEAD mode, use +/* When the OpenVPN protocol is run in AEAD mode, use * the OpenVPN packet ID as the AEAD nonce: * * 00000005 521c3b01 4308c041 diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c index 6bde4bd9395b08ea3c25c58cb99e09afdf8ad097..212d1210bc564ae804899d7c3bf8c2231e732cf1 100644 --- a/drivers/net/ovpn/peer.c +++ b/drivers/net/ovpn/peer.c @@ -12,6 +12,8 @@
#include "ovpnstruct.h" #include "bind.h" +#include "pktid.h" +#include "crypto.h" #include "io.h" #include "main.h" #include "netlink.h" @@ -42,6 +44,7 @@ struct ovpn_peer *ovpn_peer_new(struct ovpn_struct *ovpn, u32 id) peer->vpn_addrs.ipv6 = in6addr_any;
RCU_INIT_POINTER(peer->bind, NULL); + ovpn_crypto_state_init(&peer->crypto); spin_lock_init(&peer->lock); kref_init(&peer->refcount);
@@ -67,6 +70,7 @@ static void ovpn_peer_release(struct ovpn_peer *peer) if (peer->sock) ovpn_socket_put(peer->sock);
+ ovpn_crypto_state_release(&peer->crypto); ovpn_bind_reset(peer, NULL); dst_cache_destroy(&peer->dst_cache); } @@ -277,6 +281,31 @@ struct ovpn_peer *ovpn_peer_get_by_dst(struct ovpn_struct *ovpn, return peer; }
+/** + * ovpn_peer_check_by_src - check that skb source is routed via peer + * @ovpn: the openvpn instance to search + * @skb: the packet to extract source address from + * @peer: the peer to check against the source address + * + * Return: true if the peer is matching or false otherwise + */ +bool ovpn_peer_check_by_src(struct ovpn_struct *ovpn, struct sk_buff *skb, + struct ovpn_peer *peer) +{ + bool match = false; + + if (ovpn->mode == OVPN_MODE_P2P) { + /* in P2P mode, no matter the destination, packets are always + * sent to the single peer listening on the other side + */ + rcu_read_lock(); + match = (peer == rcu_dereference(ovpn->peer)); + rcu_read_unlock(); + } + + return match; +} + /** * ovpn_peer_add_p2p - add peer to related tables in a P2P instance * @ovpn: the instance to add the peer to diff --git a/drivers/net/ovpn/peer.h b/drivers/net/ovpn/peer.h index 37de5aff54a8df9adc449d1346b251b1feab0b1c..70d92cd5bd6348dd91956593d7d87224061b85d0 100644 --- a/drivers/net/ovpn/peer.h +++ b/drivers/net/ovpn/peer.h @@ -11,6 +11,8 @@ #define _NET_OVPN_OVPNPEER_H_
#include "bind.h" +#include "pktid.h" +#include "crypto.h" #include "socket.h"
#include <net/dst_cache.h> @@ -24,6 +26,7 @@ * @vpn_addrs.ipv4: IPv4 assigned to peer on the tunnel * @vpn_addrs.ipv6: IPv6 assigned to peer on the tunnel * @sock: the socket being used to talk to this peer + * @crypto: the crypto configuration (ciphers, keys, etc..) * @dst_cache: cache for dst_entry used to send to peer * @bind: remote peer binding * @halt: true if ovpn_peer_mark_delete was called @@ -41,6 +44,7 @@ struct ovpn_peer { struct in6_addr ipv6; } vpn_addrs; struct ovpn_socket *sock; + struct ovpn_crypto_state crypto; struct dst_cache dst_cache; struct ovpn_bind __rcu *bind; bool halt; @@ -83,5 +87,7 @@ struct ovpn_peer *ovpn_peer_get_by_transp_addr(struct ovpn_struct *ovpn, struct ovpn_peer *ovpn_peer_get_by_id(struct ovpn_struct *ovpn, u32 peer_id); struct ovpn_peer *ovpn_peer_get_by_dst(struct ovpn_struct *ovpn, struct sk_buff *skb); +bool ovpn_peer_check_by_src(struct ovpn_struct *ovpn, struct sk_buff *skb, + struct ovpn_peer *peer);
#endif /* _NET_OVPN_OVPNPEER_H_ */ diff --git a/drivers/net/ovpn/pktid.c b/drivers/net/ovpn/pktid.c new file mode 100644 index 0000000000000000000000000000000000000000..96dc876356706eb6e2104cf8291c1487b4441b1f --- /dev/null +++ b/drivers/net/ovpn/pktid.c @@ -0,0 +1,130 @@ +// SPDX-License-Identifier: GPL-2.0 +/* OpenVPN data channel offload + * + * Copyright (C) 2020-2024 OpenVPN, Inc. + * + * Author: Antonio Quartulli antonio@openvpn.net + * James Yonan james@openvpn.net + */ + +#include <linux/atomic.h> +#include <linux/jiffies.h> +#include <linux/net.h> +#include <linux/netdevice.h> +#include <linux/types.h> + +#include "ovpnstruct.h" +#include "main.h" +#include "packet.h" +#include "pktid.h" + +void ovpn_pktid_xmit_init(struct ovpn_pktid_xmit *pid) +{ + atomic64_set(&pid->seq_num, 1); +} + +void ovpn_pktid_recv_init(struct ovpn_pktid_recv *pr) +{ + memset(pr, 0, sizeof(*pr)); + spin_lock_init(&pr->lock); +} + +/* Packet replay detection. + * Allows ID backtrack of up to REPLAY_WINDOW_SIZE - 1. + */ +int ovpn_pktid_recv(struct ovpn_pktid_recv *pr, u32 pkt_id, u32 pkt_time) +{ + const unsigned long now = jiffies; + int ret; + + /* ID must not be zero */ + if (unlikely(pkt_id == 0)) + return -EINVAL; + + spin_lock_bh(&pr->lock); + + /* expire backtracks at or below pr->id after PKTID_RECV_EXPIRE time */ + if (unlikely(time_after_eq(now, pr->expire))) + pr->id_floor = pr->id; + + /* time changed? */ + if (unlikely(pkt_time != pr->time)) { + if (pkt_time > pr->time) { + /* time moved forward, accept */ + pr->base = 0; + pr->extent = 0; + pr->id = 0; + pr->time = pkt_time; + pr->id_floor = 0; + } else { + /* time moved backward, reject */ + ret = -ETIME; + goto out; + } + } + + if (likely(pkt_id == pr->id + 1)) { + /* well-formed ID sequence (incremented by 1) */ + pr->base = REPLAY_INDEX(pr->base, -1); + pr->history[pr->base / 8] |= (1 << (pr->base % 8)); + if (pr->extent < REPLAY_WINDOW_SIZE) + ++pr->extent; + pr->id = pkt_id; + } else if (pkt_id > pr->id) { + /* ID jumped forward by more than one */ + const unsigned int delta = pkt_id - pr->id; + + if (delta < REPLAY_WINDOW_SIZE) { + unsigned int i; + + pr->base = REPLAY_INDEX(pr->base, -delta); + pr->history[pr->base / 8] |= (1 << (pr->base % 8)); + pr->extent += delta; + if (pr->extent > REPLAY_WINDOW_SIZE) + pr->extent = REPLAY_WINDOW_SIZE; + for (i = 1; i < delta; ++i) { + unsigned int newb = REPLAY_INDEX(pr->base, i); + + pr->history[newb / 8] &= ~BIT(newb % 8); + } + } else { + pr->base = 0; + pr->extent = REPLAY_WINDOW_SIZE; + memset(pr->history, 0, sizeof(pr->history)); + pr->history[0] = 1; + } + pr->id = pkt_id; + } else { + /* ID backtrack */ + const unsigned int delta = pr->id - pkt_id; + + if (delta > pr->max_backtrack) + pr->max_backtrack = delta; + if (delta < pr->extent) { + if (pkt_id > pr->id_floor) { + const unsigned int ri = REPLAY_INDEX(pr->base, + delta); + u8 *p = &pr->history[ri / 8]; + const u8 mask = (1 << (ri % 8)); + + if (*p & mask) { + ret = -EINVAL; + goto out; + } + *p |= mask; + } else { + ret = -EINVAL; + goto out; + } + } else { + ret = -EINVAL; + goto out; + } + } + + pr->expire = now + PKTID_RECV_EXPIRE; + ret = 0; +out: + spin_unlock_bh(&pr->lock); + return ret; +} diff --git a/drivers/net/ovpn/pktid.h b/drivers/net/ovpn/pktid.h new file mode 100644 index 0000000000000000000000000000000000000000..fe02f0667e1a88a8c866fe4da4e5cebfba9efbcf --- /dev/null +++ b/drivers/net/ovpn/pktid.h @@ -0,0 +1,87 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* OpenVPN data channel offload + * + * Copyright (C) 2020-2024 OpenVPN, Inc. + * + * Author: Antonio Quartulli antonio@openvpn.net + * James Yonan james@openvpn.net + */ + +#ifndef _NET_OVPN_OVPNPKTID_H_ +#define _NET_OVPN_OVPNPKTID_H_ + +#include "packet.h" + +/* If no packets received for this length of time, set a backtrack floor + * at highest received packet ID thus far. + */ +#define PKTID_RECV_EXPIRE (30 * HZ) + +/* Packet-ID state for transmitter */ +struct ovpn_pktid_xmit { + atomic64_t seq_num; +}; + +/* replay window sizing in bytes = 2^REPLAY_WINDOW_ORDER */ +#define REPLAY_WINDOW_ORDER 8 + +#define REPLAY_WINDOW_BYTES BIT(REPLAY_WINDOW_ORDER) +#define REPLAY_WINDOW_SIZE (REPLAY_WINDOW_BYTES * 8) +#define REPLAY_INDEX(base, i) (((base) + (i)) & (REPLAY_WINDOW_SIZE - 1)) + +/* Packet-ID state for receiver. + * Other than lock member, can be zeroed to initialize. + */ +struct ovpn_pktid_recv { + /* "sliding window" bitmask of recent packet IDs received */ + u8 history[REPLAY_WINDOW_BYTES]; + /* bit position of deque base in history */ + unsigned int base; + /* extent (in bits) of deque in history */ + unsigned int extent; + /* expiration of history in jiffies */ + unsigned long expire; + /* highest sequence number received */ + u32 id; + /* highest time stamp received */ + u32 time; + /* we will only accept backtrack IDs > id_floor */ + u32 id_floor; + unsigned int max_backtrack; + /* protects entire pktd ID state */ + spinlock_t lock; +}; + +/* Get the next packet ID for xmit */ +static inline int ovpn_pktid_xmit_next(struct ovpn_pktid_xmit *pid, u32 *pktid) +{ + const s64 seq_num = atomic64_fetch_add_unless(&pid->seq_num, 1, + 0x100000000LL); + /* when the 32bit space is over, we return an error because the packet + * ID is used to create the cipher IV and we do not want to reuse the + * same value more than once + */ + if (unlikely(seq_num == 0x100000000LL)) + return -ERANGE; + + *pktid = (u32)seq_num; + + return 0; +} + +/* Write 12-byte AEAD IV to dest */ +static inline void ovpn_pktid_aead_write(const u32 pktid, + const struct ovpn_nonce_tail *nt, + unsigned char *dest) +{ + *(__force __be32 *)(dest) = htonl(pktid); + BUILD_BUG_ON(4 + sizeof(struct ovpn_nonce_tail) != NONCE_SIZE); + memcpy(dest + 4, nt->u8, sizeof(struct ovpn_nonce_tail)); +} + +void ovpn_pktid_xmit_init(struct ovpn_pktid_xmit *pid); +void ovpn_pktid_recv_init(struct ovpn_pktid_recv *pr); + +int ovpn_pktid_recv(struct ovpn_pktid_recv *pr, u32 pkt_id, u32 pkt_time); + +#endif /* _NET_OVPN_OVPNPKTID_H_ */ diff --git a/drivers/net/ovpn/proto.h b/drivers/net/ovpn/proto.h index 69604cf26bbf82539ee5cd5a7ac9c23920f555de..32af6b8e574381fb719a1b3b9de3ae1071cc4846 100644 --- a/drivers/net/ovpn/proto.h +++ b/drivers/net/ovpn/proto.h @@ -72,4 +72,35 @@ static inline u32 ovpn_peer_id_from_skb(const struct sk_buff *skb, u16 offset) return ntohl(*(__be32 *)(skb->data + offset)) & OVPN_PEER_ID_MASK; }
+/** + * ovpn_key_id_from_skb - extract key ID from the skb head + * @skb: the packet to extract the key ID code from + * + * Note: this function assumes that the skb head was pulled enough + * to access the first byte. + * + * Return: the key ID + */ +static inline u8 ovpn_key_id_from_skb(const struct sk_buff *skb) +{ + return *skb->data & OVPN_KEY_ID_MASK; +} + +/** + * ovpn_opcode_compose - combine OP code, key ID and peer ID to wire format + * @opcode: the OP code + * @key_id: the key ID + * @peer_id: the peer ID + * + * Return: a 4 bytes integer obtained combining all input values following the + * OpenVPN wire format. This integer can then be written to the packet header. + */ +static inline u32 ovpn_opcode_compose(u8 opcode, u8 key_id, u32 peer_id) +{ + const u8 op = (opcode << OVPN_OPCODE_SHIFT) | + (key_id & OVPN_KEY_ID_MASK); + + return (op << 24) | (peer_id & OVPN_PEER_ID_MASK); +} + #endif /* _NET_OVPN_OVPNPROTO_H_ */ diff --git a/drivers/net/ovpn/skb.h b/drivers/net/ovpn/skb.h index e070fe6f448c0b7a9631394ebef4554f6348ef44..3f94efae20fb58772c1a4c47df5bae8bb11ad322 100644 --- a/drivers/net/ovpn/skb.h +++ b/drivers/net/ovpn/skb.h @@ -17,8 +17,17 @@ #include <linux/socket.h> #include <linux/types.h>
-struct ovpn_cb { +struct ovpn_cb_ctx { struct ovpn_peer *peer; + struct sk_buff *skb; + struct ovpn_crypto_key_slot *ks; + struct aead_request *req; + struct scatterlist sg[MAX_SKB_FRAGS + 2]; + unsigned int payload_offset; +}; + +struct ovpn_cb { + struct ovpn_cb_ctx *ctx; };
static inline struct ovpn_cb *ovpn_skb_cb(struct sk_buff *skb)