12874c5fdSThomas Gleixner /* SPDX-License-Identifier: GPL-2.0-or-later */
22e6599cbSArnaldo Carvalho de Melo /*
32e6599cbSArnaldo Carvalho de Melo * NET Generic infrastructure for Network protocols.
42e6599cbSArnaldo Carvalho de Melo *
52e6599cbSArnaldo Carvalho de Melo * Definitions for request_sock
62e6599cbSArnaldo Carvalho de Melo *
72e6599cbSArnaldo Carvalho de Melo * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
82e6599cbSArnaldo Carvalho de Melo *
92e6599cbSArnaldo Carvalho de Melo * From code originally in include/net/tcp.h
102e6599cbSArnaldo Carvalho de Melo */
112e6599cbSArnaldo Carvalho de Melo #ifndef _REQUEST_SOCK_H
122e6599cbSArnaldo Carvalho de Melo #define _REQUEST_SOCK_H
132e6599cbSArnaldo Carvalho de Melo
142e6599cbSArnaldo Carvalho de Melo #include <linux/slab.h>
150e87506fSArnaldo Carvalho de Melo #include <linux/spinlock.h>
162e6599cbSArnaldo Carvalho de Melo #include <linux/types.h>
17547b792cSIlpo Järvinen #include <linux/bug.h>
1841c6d650SReshetova, Elena #include <linux/refcount.h>
190e87506fSArnaldo Carvalho de Melo
202e6599cbSArnaldo Carvalho de Melo #include <net/sock.h>
212e6599cbSArnaldo Carvalho de Melo
2260236fddSArnaldo Carvalho de Melo struct request_sock;
232e6599cbSArnaldo Carvalho de Melo struct sk_buff;
242e6599cbSArnaldo Carvalho de Melo struct dst_entry;
252e6599cbSArnaldo Carvalho de Melo struct proto;
262e6599cbSArnaldo Carvalho de Melo
2760236fddSArnaldo Carvalho de Melo struct request_sock_ops {
282e6599cbSArnaldo Carvalho de Melo int family;
29417ccf6bSAlexey Dobriyan unsigned int obj_size;
30e18b890bSChristoph Lameter struct kmem_cache *slab;
317e56b5d6SCatalin Marinas char *slab_name;
32ea3bea3aSEric Dumazet int (*rtx_syn_ack)(const struct sock *sk,
331a2c6181SChristoph Paasch struct request_sock *req);
34a00e7444SEric Dumazet void (*send_ack)(const struct sock *sk, struct sk_buff *skb,
3560236fddSArnaldo Carvalho de Melo struct request_sock *req);
36a00e7444SEric Dumazet void (*send_reset)(const struct sock *sk,
37cfb6eeb4SYOSHIFUJI Hideaki struct sk_buff *skb);
3860236fddSArnaldo Carvalho de Melo void (*destructor)(struct request_sock *req);
3942cb80a2SEric Dumazet void (*syn_ack_timeout)(const struct request_sock *req);
402e6599cbSArnaldo Carvalho de Melo };
412e6599cbSArnaldo Carvalho de Melo
421b70e977SEric Dumazet int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req);
43e6c022a4SEric Dumazet
4470a217f1SMartin KaFai Lau struct saved_syn {
45267cf9faSMartin KaFai Lau u32 mac_hdrlen;
4670a217f1SMartin KaFai Lau u32 network_hdrlen;
4770a217f1SMartin KaFai Lau u32 tcp_hdrlen;
4870a217f1SMartin KaFai Lau u8 data[];
4970a217f1SMartin KaFai Lau };
5070a217f1SMartin KaFai Lau
5160236fddSArnaldo Carvalho de Melo /* struct request_sock - mini sock to represent a connection request
522e6599cbSArnaldo Carvalho de Melo */
5360236fddSArnaldo Carvalho de Melo struct request_sock {
54634fb979SEric Dumazet struct sock_common __req_common;
551e2e0117SEric Dumazet #define rsk_refcnt __req_common.skc_refcnt
5652452c54SEric Dumazet #define rsk_hash __req_common.skc_hash
578e5eb54dSEric Dumazet #define rsk_listener __req_common.skc_listener
58ed53d0abSEric Dumazet #define rsk_window_clamp __req_common.skc_window_clamp
59ed53d0abSEric Dumazet #define rsk_rcv_wnd __req_common.skc_rcv_wnd
601e2e0117SEric Dumazet
613fb62c5dSEric Dumazet struct request_sock *dl_next;
622e6599cbSArnaldo Carvalho de Melo u16 mss;
63e6c022a4SEric Dumazet u8 num_retrans; /* number of retransmits */
64f8ace8d9SFlorian Westphal u8 syncookie:1; /* syncookie: encode tcpopts in timestamp */
65e6c022a4SEric Dumazet u8 num_timeout:7; /* number of timeouts */
662e6599cbSArnaldo Carvalho de Melo u32 ts_recent;
67fa76ce73SEric Dumazet struct timer_list rsk_timer;
6872a3effaSEric Dumazet const struct request_sock_ops *rsk_ops;
692e6599cbSArnaldo Carvalho de Melo struct sock *sk;
7070a217f1SMartin KaFai Lau struct saved_syn *saved_syn;
714237c75cSVenkat Yekkirala u32 secid;
726b877699SVenkat Yekkirala u32 peer_secid;
73*5903123fSAkhmat Karakotov u32 timeout;
742e6599cbSArnaldo Carvalho de Melo };
752e6599cbSArnaldo Carvalho de Melo
inet_reqsk(const struct sock * sk)76b1f0a0e9SFlorian Westphal static inline struct request_sock *inet_reqsk(const struct sock *sk)
77b267cdd1SEric Dumazet {
78b267cdd1SEric Dumazet return (struct request_sock *)sk;
79b267cdd1SEric Dumazet }
80b267cdd1SEric Dumazet
req_to_sk(struct request_sock * req)81b267cdd1SEric Dumazet static inline struct sock *req_to_sk(struct request_sock *req)
82b267cdd1SEric Dumazet {
83b267cdd1SEric Dumazet return (struct sock *)req;
84b267cdd1SEric Dumazet }
85b267cdd1SEric Dumazet
864e9a578eSEric Dumazet static inline struct request_sock *
reqsk_alloc(const struct request_sock_ops * ops,struct sock * sk_listener,bool attach_listener)87a1a5344dSEric Dumazet reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener,
88a1a5344dSEric Dumazet bool attach_listener)
892e6599cbSArnaldo Carvalho de Melo {
90e96f78abSEric Dumazet struct request_sock *req;
91e96f78abSEric Dumazet
92e96f78abSEric Dumazet req = kmem_cache_alloc(ops->slab, GFP_ATOMIC | __GFP_NOWARN);
933a5d1c0eSEric Dumazet if (!req)
943a5d1c0eSEric Dumazet return NULL;
95a1a5344dSEric Dumazet req->rsk_listener = NULL;
963a5d1c0eSEric Dumazet if (attach_listener) {
9741c6d650SReshetova, Elena if (unlikely(!refcount_inc_not_zero(&sk_listener->sk_refcnt))) {
983a5d1c0eSEric Dumazet kmem_cache_free(ops->slab, req);
993a5d1c0eSEric Dumazet return NULL;
100a1a5344dSEric Dumazet }
1013a5d1c0eSEric Dumazet req->rsk_listener = sk_listener;
1023a5d1c0eSEric Dumazet }
1033a5d1c0eSEric Dumazet req->rsk_ops = ops;
104b267cdd1SEric Dumazet req_to_sk(req)->sk_prot = sk_listener->sk_prot;
105b267cdd1SEric Dumazet sk_node_init(&req_to_sk(req)->sk_node);
106004a5d01SEric Dumazet sk_tx_queue_clear(req_to_sk(req));
107cd8ae852SEric Dumazet req->saved_syn = NULL;
108*5903123fSAkhmat Karakotov req->timeout = 0;
10985f9aa75SEric Dumazet req->num_timeout = 0;
11085f9aa75SEric Dumazet req->num_retrans = 0;
11185f9aa75SEric Dumazet req->sk = NULL;
11241c6d650SReshetova, Elena refcount_set(&req->rsk_refcnt, 0);
1133a5d1c0eSEric Dumazet
1142e6599cbSArnaldo Carvalho de Melo return req;
1152e6599cbSArnaldo Carvalho de Melo }
1162e6599cbSArnaldo Carvalho de Melo
__reqsk_free(struct request_sock * req)1179403cf23SGuillaume Nault static inline void __reqsk_free(struct request_sock *req)
1182e6599cbSArnaldo Carvalho de Melo {
11960236fddSArnaldo Carvalho de Melo req->rsk_ops->destructor(req);
1204e9a578eSEric Dumazet if (req->rsk_listener)
1214e9a578eSEric Dumazet sock_put(req->rsk_listener);
122cd8ae852SEric Dumazet kfree(req->saved_syn);
12313854e5aSEric Dumazet kmem_cache_free(req->rsk_ops->slab, req);
1242e6599cbSArnaldo Carvalho de Melo }
1252e6599cbSArnaldo Carvalho de Melo
reqsk_free(struct request_sock * req)1269403cf23SGuillaume Nault static inline void reqsk_free(struct request_sock *req)
1279403cf23SGuillaume Nault {
1289403cf23SGuillaume Nault WARN_ON_ONCE(refcount_read(&req->rsk_refcnt) != 0);
1299403cf23SGuillaume Nault __reqsk_free(req);
1309403cf23SGuillaume Nault }
1319403cf23SGuillaume Nault
reqsk_put(struct request_sock * req)1321e2e0117SEric Dumazet static inline void reqsk_put(struct request_sock *req)
1331e2e0117SEric Dumazet {
13441c6d650SReshetova, Elena if (refcount_dec_and_test(&req->rsk_refcnt))
1351e2e0117SEric Dumazet reqsk_free(req);
1361e2e0117SEric Dumazet }
1370e87506fSArnaldo Carvalho de Melo
13810467163SJerry Chu /*
13910467163SJerry Chu * For a TCP Fast Open listener -
14010467163SJerry Chu * lock - protects the access to all the reqsk, which is co-owned by
14110467163SJerry Chu * the listener and the child socket.
14210467163SJerry Chu * qlen - pending TFO requests (still in TCP_SYN_RECV).
14310467163SJerry Chu * max_qlen - max TFO reqs allowed before TFO is disabled.
14410467163SJerry Chu *
14510467163SJerry Chu * XXX (TFO) - ideally these fields can be made as part of "listen_sock"
14610467163SJerry Chu * structure above. But there is some implementation difficulty due to
14710467163SJerry Chu * listen_sock being part of request_sock_queue hence will be freed when
14810467163SJerry Chu * a listener is stopped. But TFO related fields may continue to be
14910467163SJerry Chu * accessed even after a listener is closed, until its sk_refcnt drops
15010467163SJerry Chu * to 0 implying no more outstanding TFO reqs. One solution is to keep
15110467163SJerry Chu * listen_opt around until sk_refcnt drops to 0. But there is some other
15210467163SJerry Chu * complexity that needs to be resolved. E.g., a listener can be disabled
15310467163SJerry Chu * temporarily through shutdown()->tcp_disconnect(), and re-enabled later.
15410467163SJerry Chu */
15510467163SJerry Chu struct fastopen_queue {
15610467163SJerry Chu struct request_sock *rskq_rst_head; /* Keep track of past TFO */
15710467163SJerry Chu struct request_sock *rskq_rst_tail; /* requests that caused RST.
15810467163SJerry Chu * This is part of the defense
15910467163SJerry Chu * against spoofing attack.
16010467163SJerry Chu */
16110467163SJerry Chu spinlock_t lock;
16210467163SJerry Chu int qlen; /* # of pending (TCP_SYN_RECV) reqs */
16310467163SJerry Chu int max_qlen; /* != 0 iff TFO is currently enabled */
1641fba70e5SYuchung Cheng
1651fba70e5SYuchung Cheng struct tcp_fastopen_context __rcu *ctx; /* cipher context for cookie */
16610467163SJerry Chu };
16710467163SJerry Chu
1680e87506fSArnaldo Carvalho de Melo /** struct request_sock_queue - queue of request_socks
1690e87506fSArnaldo Carvalho de Melo *
1700e87506fSArnaldo Carvalho de Melo * @rskq_accept_head - FIFO head of established children
1710e87506fSArnaldo Carvalho de Melo * @rskq_accept_tail - FIFO tail of established children
172295f7324SArnaldo Carvalho de Melo * @rskq_defer_accept - User waits for some data after accept()
1730e87506fSArnaldo Carvalho de Melo *
1740e87506fSArnaldo Carvalho de Melo */
1750e87506fSArnaldo Carvalho de Melo struct request_sock_queue {
176fff1f300SEric Dumazet spinlock_t rskq_lock;
177fff1f300SEric Dumazet u8 rskq_defer_accept;
178ef547f2aSEric Dumazet
1798d2675f1SEric Dumazet u32 synflood_warned;
180aac065c5SEric Dumazet atomic_t qlen;
181aac065c5SEric Dumazet atomic_t young;
182aac065c5SEric Dumazet
1830e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_head;
1840e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_tail;
1850536fcc0SEric Dumazet struct fastopen_queue fastopenq; /* Check max_qlen != 0 to determine
1860536fcc0SEric Dumazet * if TFO is enabled.
18710467163SJerry Chu */
1880e87506fSArnaldo Carvalho de Melo };
1890e87506fSArnaldo Carvalho de Melo
190ef547f2aSEric Dumazet void reqsk_queue_alloc(struct request_sock_queue *queue);
1910e87506fSArnaldo Carvalho de Melo
192c0f4502aSJoe Perches void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req,
193c0f4502aSJoe Perches bool reset);
19483e3609eSArnaldo Carvalho de Melo
reqsk_queue_empty(const struct request_sock_queue * queue)195fff1f300SEric Dumazet static inline bool reqsk_queue_empty(const struct request_sock_queue *queue)
1960e87506fSArnaldo Carvalho de Melo {
19760b173caSEric Dumazet return READ_ONCE(queue->rskq_accept_head) == NULL;
1980e87506fSArnaldo Carvalho de Melo }
1990e87506fSArnaldo Carvalho de Melo
reqsk_queue_remove(struct request_sock_queue * queue,struct sock * parent)200fff1f300SEric Dumazet static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue,
201fff1f300SEric Dumazet struct sock *parent)
2020e87506fSArnaldo Carvalho de Melo {
203fff1f300SEric Dumazet struct request_sock *req;
2040e87506fSArnaldo Carvalho de Melo
205fff1f300SEric Dumazet spin_lock_bh(&queue->rskq_lock);
206fff1f300SEric Dumazet req = queue->rskq_accept_head;
207fff1f300SEric Dumazet if (req) {
208fff1f300SEric Dumazet sk_acceptq_removed(parent);
20960b173caSEric Dumazet WRITE_ONCE(queue->rskq_accept_head, req->dl_next);
2100e87506fSArnaldo Carvalho de Melo if (queue->rskq_accept_head == NULL)
2110e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail = NULL;
212fff1f300SEric Dumazet }
213fff1f300SEric Dumazet spin_unlock_bh(&queue->rskq_lock);
2140e87506fSArnaldo Carvalho de Melo return req;
2150e87506fSArnaldo Carvalho de Melo }
2160e87506fSArnaldo Carvalho de Melo
reqsk_queue_removed(struct request_sock_queue * queue,const struct request_sock * req)217fa76ce73SEric Dumazet static inline void reqsk_queue_removed(struct request_sock_queue *queue,
218fa76ce73SEric Dumazet const struct request_sock *req)
2190e87506fSArnaldo Carvalho de Melo {
220e6c022a4SEric Dumazet if (req->num_timeout == 0)
221aac065c5SEric Dumazet atomic_dec(&queue->young);
222aac065c5SEric Dumazet atomic_dec(&queue->qlen);
2230e87506fSArnaldo Carvalho de Melo }
2240e87506fSArnaldo Carvalho de Melo
reqsk_queue_added(struct request_sock_queue * queue)225fa76ce73SEric Dumazet static inline void reqsk_queue_added(struct request_sock_queue *queue)
2260e87506fSArnaldo Carvalho de Melo {
227aac065c5SEric Dumazet atomic_inc(&queue->young);
228aac065c5SEric Dumazet atomic_inc(&queue->qlen);
2290e87506fSArnaldo Carvalho de Melo }
2300e87506fSArnaldo Carvalho de Melo
reqsk_queue_len(const struct request_sock_queue * queue)231463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len(const struct request_sock_queue *queue)
2320e87506fSArnaldo Carvalho de Melo {
233aac065c5SEric Dumazet return atomic_read(&queue->qlen);
2340e87506fSArnaldo Carvalho de Melo }
2350e87506fSArnaldo Carvalho de Melo
reqsk_queue_len_young(const struct request_sock_queue * queue)236463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
2370e87506fSArnaldo Carvalho de Melo {
238aac065c5SEric Dumazet return atomic_read(&queue->young);
2390e87506fSArnaldo Carvalho de Melo }
2400e87506fSArnaldo Carvalho de Melo
2412e6599cbSArnaldo Carvalho de Melo #endif /* _REQUEST_SOCK_H */
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