1/* SPDX-License-Identifier: GPL-2.0-or-later */
2#ifndef _TCP_AO_H
3#define _TCP_AO_H
4
5#define TCP_AO_KEY_ALIGN 1
6#define __tcp_ao_key_align __aligned(TCP_AO_KEY_ALIGN)
7
8union tcp_ao_addr {
9 struct in_addr a4;
10#if IS_ENABLED(CONFIG_IPV6)
11 struct in6_addr a6;
12#endif
13};
14
15struct tcp_ao_hdr {
16 u8 kind;
17 u8 length;
18 u8 keyid;
19 u8 rnext_keyid;
20};
21
22static inline u8 tcp_ao_hdr_maclen(const struct tcp_ao_hdr *aoh)
23{
24 return aoh->length - sizeof(struct tcp_ao_hdr);
25}
26
27struct tcp_ao_counters {
28 atomic64_t pkt_good;
29 atomic64_t pkt_bad;
30 atomic64_t key_not_found;
31 atomic64_t ao_required;
32 atomic64_t dropped_icmp;
33};
34
35struct tcp_ao_key {
36 struct hlist_node node;
37 union tcp_ao_addr addr;
38 u8 key[TCP_AO_MAXKEYLEN] __tcp_ao_key_align;
39 unsigned int tcp_sigpool_id;
40 unsigned int digest_size;
41 int l3index;
42 u8 prefixlen;
43 u8 family;
44 u8 keylen;
45 u8 keyflags;
46 u8 sndid;
47 u8 rcvid;
48 u8 maclen;
49 struct rcu_head rcu;
50 atomic64_t pkt_good;
51 atomic64_t pkt_bad;
52 u8 traffic_keys[];
53};
54
55static inline u8 *rcv_other_key(struct tcp_ao_key *key)
56{
57 return key->traffic_keys;
58}
59
60static inline u8 *snd_other_key(struct tcp_ao_key *key)
61{
62 return key->traffic_keys + key->digest_size;
63}
64
65static inline int tcp_ao_maclen(const struct tcp_ao_key *key)
66{
67 return key->maclen;
68}
69
70/* Use tcp_ao_len_aligned() for TCP header calculations */
71static inline int tcp_ao_len(const struct tcp_ao_key *key)
72{
73 return tcp_ao_maclen(key) + sizeof(struct tcp_ao_hdr);
74}
75
76static inline int tcp_ao_len_aligned(const struct tcp_ao_key *key)
77{
78 return round_up(tcp_ao_len(key), 4);
79}
80
81static inline unsigned int tcp_ao_digest_size(struct tcp_ao_key *key)
82{
83 return key->digest_size;
84}
85
86static inline int tcp_ao_sizeof_key(const struct tcp_ao_key *key)
87{
88 return sizeof(struct tcp_ao_key) + (key->digest_size << 1);
89}
90
91struct tcp_ao_info {
92 /* List of tcp_ao_key's */
93 struct hlist_head head;
94 /* current_key and rnext_key are maintained on sockets
95 * in TCP_AO_ESTABLISHED states.
96 * Their purpose is to cache keys on established connections,
97 * saving needless lookups. Never dereference any of them from
98 * listen sockets.
99 * ::current_key may change in RX to the key that was requested by
100 * the peer, please use READ_ONCE()/WRITE_ONCE() in order to avoid
101 * load/store tearing.
102 * Do the same for ::rnext_key, if you don't hold socket lock
103 * (it's changed only by userspace request in setsockopt()).
104 */
105 struct tcp_ao_key *current_key;
106 struct tcp_ao_key *rnext_key;
107 struct tcp_ao_counters counters;
108 u32 ao_required :1,
109 accept_icmps :1,
110 __unused :30;
111 __be32 lisn;
112 __be32 risn;
113 /* Sequence Number Extension (SNE) are upper 4 bytes for SEQ,
114 * that protect TCP-AO connection from replayed old TCP segments.
115 * See RFC5925 (6.2).
116 * In order to get correct SNE, there's a helper tcp_ao_compute_sne().
117 * It needs SEQ basis to understand whereabouts are lower SEQ numbers.
118 * According to that basis vector, it can provide incremented SNE
119 * when SEQ rolls over or provide decremented SNE when there's
120 * a retransmitted segment from before-rolling over.
121 * - for request sockets such basis is rcv_isn/snt_isn, which seems
122 * good enough as it's unexpected to receive 4 Gbytes on reqsk.
123 * - for full sockets the basis is rcv_nxt/snd_una. snd_una is
124 * taken instead of snd_nxt as currently it's easier to track
125 * in tcp_snd_una_update(), rather than updating SNE in all
126 * WRITE_ONCE(tp->snd_nxt, ...)
127 * - for time-wait sockets the basis is tw_rcv_nxt/tw_snd_nxt.
128 * tw_snd_nxt is not expected to change, while tw_rcv_nxt may.
129 */
130 u32 snd_sne;
131 u32 rcv_sne;
132 refcount_t refcnt; /* Protects twsk destruction */
133};
134
135#ifdef CONFIG_TCP_MD5SIG
136#include <linux/jump_label.h>
137extern struct static_key_false_deferred tcp_md5_needed;
138#define static_branch_tcp_md5() static_branch_unlikely(&tcp_md5_needed.key)
139#else
140#define static_branch_tcp_md5() false
141#endif
142#ifdef CONFIG_TCP_AO
143/* TCP-AO structures and functions */
144#include <linux/jump_label.h>
145extern struct static_key_false_deferred tcp_ao_needed;
146#define static_branch_tcp_ao() static_branch_unlikely(&tcp_ao_needed.key)
147#else
148#define static_branch_tcp_ao() false
149#endif
150
151#ifdef CONFIG_TCP_AO
152/* TCP-AO structures and functions */
153struct tcp4_ao_context {
154 __be32 saddr;
155 __be32 daddr;
156 __be16 sport;
157 __be16 dport;
158 __be32 sisn;
159 __be32 disn;
160};
161
162struct tcp6_ao_context {
163 struct in6_addr saddr;
164 struct in6_addr daddr;
165 __be16 sport;
166 __be16 dport;
167 __be32 sisn;
168 __be32 disn;
169};
170
171struct tcp_sigpool;
172/* Established states are fast-path and there always is current_key/rnext_key */
173#define TCP_AO_ESTABLISHED (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | \
174 TCPF_CLOSE_WAIT | TCPF_LAST_ACK | TCPF_CLOSING)
175
176int tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb,
177 struct tcp_ao_key *key, struct tcphdr *th,
178 __u8 *hash_location);
179int tcp_ao_hash_skb(unsigned short int family,
180 char *ao_hash, struct tcp_ao_key *key,
181 const struct sock *sk, const struct sk_buff *skb,
182 const u8 *tkey, int hash_offset, u32 sne);
183int tcp_parse_ao(struct sock *sk, int cmd, unsigned short int family,
184 sockptr_t optval, int optlen);
185struct tcp_ao_key *tcp_ao_established_key(const struct sock *sk,
186 struct tcp_ao_info *ao,
187 int sndid, int rcvid);
188int tcp_ao_copy_all_matching(const struct sock *sk, struct sock *newsk,
189 struct request_sock *req, struct sk_buff *skb,
190 int family);
191int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx,
192 unsigned int len, struct tcp_sigpool *hp);
193void tcp_ao_destroy_sock(struct sock *sk, bool twsk);
194void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp);
195bool tcp_ao_ignore_icmp(const struct sock *sk, int family, int type, int code);
196int tcp_ao_get_mkts(struct sock *sk, sockptr_t optval, sockptr_t optlen);
197int tcp_ao_get_sock_info(struct sock *sk, sockptr_t optval, sockptr_t optlen);
198int tcp_ao_get_repair(struct sock *sk, sockptr_t optval, sockptr_t optlen);
199int tcp_ao_set_repair(struct sock *sk, sockptr_t optval, unsigned int optlen);
200enum skb_drop_reason tcp_inbound_ao_hash(struct sock *sk,
201 const struct sk_buff *skb, unsigned short int family,
202 const struct request_sock *req, int l3index,
203 const struct tcp_ao_hdr *aoh);
204u32 tcp_ao_compute_sne(u32 next_sne, u32 next_seq, u32 seq);
205struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, int l3index,
206 const union tcp_ao_addr *addr,
207 int family, int sndid, int rcvid);
208int tcp_ao_hash_hdr(unsigned short family, char *ao_hash,
209 struct tcp_ao_key *key, const u8 *tkey,
210 const union tcp_ao_addr *daddr,
211 const union tcp_ao_addr *saddr,
212 const struct tcphdr *th, u32 sne);
213int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb,
214 const struct tcp_ao_hdr *aoh, int l3index, u32 seq,
215 struct tcp_ao_key **key, char **traffic_key,
216 bool *allocated_traffic_key, u8 *keyid, u32 *sne);
217
218/* ipv4 specific functions */
219int tcp_v4_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen);
220struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk,
221 int sndid, int rcvid);
222int tcp_v4_ao_synack_hash(char *ao_hash, struct tcp_ao_key *mkt,
223 struct request_sock *req, const struct sk_buff *skb,
224 int hash_offset, u32 sne);
225int tcp_v4_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key,
226 const struct sock *sk,
227 __be32 sisn, __be32 disn, bool send);
228int tcp_v4_ao_calc_key_rsk(struct tcp_ao_key *mkt, u8 *key,
229 struct request_sock *req);
230struct tcp_ao_key *tcp_v4_ao_lookup_rsk(const struct sock *sk,
231 struct request_sock *req,
232 int sndid, int rcvid);
233int tcp_v4_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key,
234 const struct sock *sk, const struct sk_buff *skb,
235 const u8 *tkey, int hash_offset, u32 sne);
236/* ipv6 specific functions */
237int tcp_v6_ao_hash_pseudoheader(struct tcp_sigpool *hp,
238 const struct in6_addr *daddr,
239 const struct in6_addr *saddr, int nbytes);
240int tcp_v6_ao_calc_key_skb(struct tcp_ao_key *mkt, u8 *key,
241 const struct sk_buff *skb, __be32 sisn, __be32 disn);
242int tcp_v6_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key,
243 const struct sock *sk, __be32 sisn,
244 __be32 disn, bool send);
245int tcp_v6_ao_calc_key_rsk(struct tcp_ao_key *mkt, u8 *key,
246 struct request_sock *req);
247struct tcp_ao_key *tcp_v6_ao_lookup(const struct sock *sk,
248 struct sock *addr_sk, int sndid, int rcvid);
249struct tcp_ao_key *tcp_v6_ao_lookup_rsk(const struct sock *sk,
250 struct request_sock *req,
251 int sndid, int rcvid);
252int tcp_v6_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key,
253 const struct sock *sk, const struct sk_buff *skb,
254 const u8 *tkey, int hash_offset, u32 sne);
255int tcp_v6_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen);
256int tcp_v6_ao_synack_hash(char *ao_hash, struct tcp_ao_key *ao_key,
257 struct request_sock *req, const struct sk_buff *skb,
258 int hash_offset, u32 sne);
259void tcp_ao_established(struct sock *sk);
260void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb);
261void tcp_ao_connect_init(struct sock *sk);
262void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb,
263 struct request_sock *req, unsigned short int family);
264#else /* CONFIG_TCP_AO */
265
266static inline int tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb,
267 struct tcp_ao_key *key, struct tcphdr *th,
268 __u8 *hash_location)
269{
270 return 0;
271}
272
273static inline void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb,
274 struct request_sock *req, unsigned short int family)
275{
276}
277
278static inline bool tcp_ao_ignore_icmp(const struct sock *sk, int family,
279 int type, int code)
280{
281 return false;
282}
283
284static inline enum skb_drop_reason tcp_inbound_ao_hash(struct sock *sk,
285 const struct sk_buff *skb, unsigned short int family,
286 const struct request_sock *req, int l3index,
287 const struct tcp_ao_hdr *aoh)
288{
289 return SKB_NOT_DROPPED_YET;
290}
291
292static inline struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk,
293 int l3index, const union tcp_ao_addr *addr,
294 int family, int sndid, int rcvid)
295{
296 return NULL;
297}
298
299static inline void tcp_ao_destroy_sock(struct sock *sk, bool twsk)
300{
301}
302
303static inline void tcp_ao_established(struct sock *sk)
304{
305}
306
307static inline void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb)
308{
309}
310
311static inline void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw,
312 struct tcp_sock *tp)
313{
314}
315
316static inline void tcp_ao_connect_init(struct sock *sk)
317{
318}
319
320static inline int tcp_ao_get_mkts(struct sock *sk, sockptr_t optval, sockptr_t optlen)
321{
322 return -ENOPROTOOPT;
323}
324
325static inline int tcp_ao_get_sock_info(struct sock *sk, sockptr_t optval, sockptr_t optlen)
326{
327 return -ENOPROTOOPT;
328}
329
330static inline int tcp_ao_get_repair(struct sock *sk,
331 sockptr_t optval, sockptr_t optlen)
332{
333 return -ENOPROTOOPT;
334}
335
336static inline int tcp_ao_set_repair(struct sock *sk,
337 sockptr_t optval, unsigned int optlen)
338{
339 return -ENOPROTOOPT;
340}
341#endif
342
343#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
344int tcp_do_parse_auth_options(const struct tcphdr *th,
345 const u8 **md5_hash, const u8 **ao_hash);
346#else
347static inline int tcp_do_parse_auth_options(const struct tcphdr *th,
348 const u8 **md5_hash, const u8 **ao_hash)
349{
350 *md5_hash = NULL;
351 *ao_hash = NULL;
352 return 0;
353}
354#endif
355
356#endif /* _TCP_AO_H */
357

source code of linux/include/net/tcp_ao.h