functions.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2
  3#ifndef __NET_PSP_HELPERS_H
  4#define __NET_PSP_HELPERS_H
  5
  6#include <linux/skbuff.h>
  7#include <linux/rcupdate.h>
  8#include <linux/udp.h>
  9#include <net/sock.h>
 10#include <net/tcp.h>
 11#include <net/psp/types.h>
 12
 13struct inet_timewait_sock;
 14
 15/* Driver-facing API */
 16struct psp_dev *
 17psp_dev_create(struct net_device *netdev, struct psp_dev_ops *psd_ops,
 18	       struct psp_dev_caps *psd_caps, void *priv_ptr);
 19void psp_dev_unregister(struct psp_dev *psd);
 20bool psp_dev_encapsulate(struct net *net, struct sk_buff *skb, __be32 spi,
 21			 u8 ver, __be16 sport);
 22int psp_dev_rcv(struct sk_buff *skb, u16 dev_id, u8 generation, bool strip_icv);
 23
 24/* Kernel-facing API */
 25void psp_assoc_put(struct psp_assoc *pas);
 26
 27static inline void *psp_assoc_drv_data(struct psp_assoc *pas)
 28{
 29	return pas->drv_data;
 30}
 31
 32#if IS_ENABLED(CONFIG_INET_PSP)
 33unsigned int psp_key_size(u32 version);
 34void psp_sk_assoc_free(struct sock *sk);
 35void psp_twsk_init(struct inet_timewait_sock *tw, const struct sock *sk);
 36void psp_twsk_assoc_free(struct inet_timewait_sock *tw);
 37void psp_reply_set_decrypted(const struct sock *sk, struct sk_buff *skb);
 38
 39static inline struct psp_assoc *psp_sk_assoc(const struct sock *sk)
 40{
 41	return rcu_dereference_check(sk->psp_assoc, lockdep_sock_is_held(sk));
 42}
 43
 44static inline void
 45psp_enqueue_set_decrypted(struct sock *sk, struct sk_buff *skb)
 46{
 47	struct psp_assoc *pas;
 48
 49	pas = psp_sk_assoc(sk);
 50	if (pas && pas->tx.spi)
 51		skb->decrypted = 1;
 52}
 53
 54static inline unsigned long
 55__psp_skb_coalesce_diff(const struct sk_buff *one, const struct sk_buff *two,
 56			unsigned long diffs)
 57{
 58	struct psp_skb_ext *a, *b;
 59
 60	a = skb_ext_find(one, SKB_EXT_PSP);
 61	b = skb_ext_find(two, SKB_EXT_PSP);
 62
 63	diffs |= (!!a) ^ (!!b);
 64	if (!diffs && unlikely(a))
 65		diffs |= memcmp(a, b, sizeof(*a));
 66	return diffs;
 67}
 68
 69static inline bool
 70psp_is_allowed_nondata(struct sk_buff *skb, struct psp_assoc *pas)
 71{
 72	bool fin = !!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN);
 73	u32 end_seq = TCP_SKB_CB(skb)->end_seq;
 74	u32 seq = TCP_SKB_CB(skb)->seq;
 75	bool pure_fin;
 76
 77	pure_fin = fin && end_seq - seq == 1;
 78
 79	return seq == end_seq || (pure_fin && seq == pas->upgrade_seq);
 80}
 81
 82static inline bool
 83psp_pse_matches_pas(struct psp_skb_ext *pse, struct psp_assoc *pas)
 84{
 85	return pse && pas->rx.spi == pse->spi &&
 86	       pas->generation == pse->generation &&
 87	       pas->version == pse->version &&
 88	       pas->dev_id == pse->dev_id;
 89}
 90
 91static inline enum skb_drop_reason
 92__psp_sk_rx_policy_check(struct sk_buff *skb, struct psp_assoc *pas)
 93{
 94	struct psp_skb_ext *pse = skb_ext_find(skb, SKB_EXT_PSP);
 95
 96	if (!pas)
 97		return pse ? SKB_DROP_REASON_PSP_INPUT : 0;
 98
 99	if (likely(psp_pse_matches_pas(pse, pas))) {
100		if (unlikely(!pas->peer_tx))
101			pas->peer_tx = 1;
102
103		return 0;
104	}
105
106	if (!pse) {
107		if (!pas->tx.spi ||
108		    (!pas->peer_tx && psp_is_allowed_nondata(skb, pas)))
109			return 0;
110	}
111
112	return SKB_DROP_REASON_PSP_INPUT;
113}
114
115static inline enum skb_drop_reason
116psp_sk_rx_policy_check(struct sock *sk, struct sk_buff *skb)
117{
118	return __psp_sk_rx_policy_check(skb, psp_sk_assoc(sk));
119}
120
121static inline enum skb_drop_reason
122psp_twsk_rx_policy_check(struct inet_timewait_sock *tw, struct sk_buff *skb)
123{
124	return __psp_sk_rx_policy_check(skb, rcu_dereference(tw->psp_assoc));
125}
126
127static inline struct psp_assoc *psp_sk_get_assoc_rcu(const struct sock *sk)
128{
129	struct psp_assoc *pas;
130	int state;
131
132	state = READ_ONCE(sk->sk_state);
133	if (!sk_is_inet(sk) || state == TCP_NEW_SYN_RECV)
134		return NULL;
135
136	pas = state == TCP_TIME_WAIT ?
137		      rcu_dereference(inet_twsk(sk)->psp_assoc) :
138		      rcu_dereference(sk->psp_assoc);
139	return pas;
140}
141
142static inline struct psp_assoc *psp_skb_get_assoc_rcu(struct sk_buff *skb)
143{
144	if (!skb->decrypted || !skb->sk)
145		return NULL;
146
147	return psp_sk_get_assoc_rcu(skb->sk);
148}
149
150static inline unsigned int psp_sk_overhead(const struct sock *sk)
151{
152	int psp_encap = sizeof(struct udphdr) + PSP_HDR_SIZE + PSP_TRL_SIZE;
153	bool has_psp = rcu_access_pointer(sk->psp_assoc);
154
155	return has_psp ? psp_encap : 0;
156}
157#else
158static inline void psp_sk_assoc_free(struct sock *sk) { }
159static inline void
160psp_twsk_init(struct inet_timewait_sock *tw, const struct sock *sk) { }
161static inline void psp_twsk_assoc_free(struct inet_timewait_sock *tw) { }
162static inline void
163psp_reply_set_decrypted(const struct sock *sk, struct sk_buff *skb) { }
164
165static inline struct psp_assoc *psp_sk_assoc(const struct sock *sk)
166{
167	return NULL;
168}
169
170static inline void
171psp_enqueue_set_decrypted(struct sock *sk, struct sk_buff *skb) { }
172
173static inline unsigned long
174__psp_skb_coalesce_diff(const struct sk_buff *one, const struct sk_buff *two,
175			unsigned long diffs)
176{
177	return diffs;
178}
179
180static inline enum skb_drop_reason
181psp_sk_rx_policy_check(struct sock *sk, struct sk_buff *skb)
182{
183	return 0;
184}
185
186static inline enum skb_drop_reason
187psp_twsk_rx_policy_check(struct inet_timewait_sock *tw, struct sk_buff *skb)
188{
189	return 0;
190}
191
192static inline struct psp_assoc *psp_skb_get_assoc_rcu(struct sk_buff *skb)
193{
194	return NULL;
195}
196
197static inline unsigned int psp_sk_overhead(const struct sock *sk)
198{
199	return 0;
200}
201#endif
202
203static inline unsigned long
204psp_skb_coalesce_diff(const struct sk_buff *one, const struct sk_buff *two)
205{
206	return __psp_skb_coalesce_diff(one, two, 0);
207}
208
209#endif /* __NET_PSP_HELPERS_H */