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 4460236fddSArnaldo Carvalho de Melo /* struct request_sock - mini sock to represent a connection request 452e6599cbSArnaldo Carvalho de Melo */ 4660236fddSArnaldo Carvalho de Melo struct request_sock { 47634fb979SEric Dumazet struct sock_common __req_common; 481e2e0117SEric Dumazet #define rsk_refcnt __req_common.skc_refcnt 4952452c54SEric Dumazet #define rsk_hash __req_common.skc_hash 508e5eb54dSEric Dumazet #define rsk_listener __req_common.skc_listener 51ed53d0abSEric Dumazet #define rsk_window_clamp __req_common.skc_window_clamp 52ed53d0abSEric Dumazet #define rsk_rcv_wnd __req_common.skc_rcv_wnd 531e2e0117SEric Dumazet 543fb62c5dSEric Dumazet struct request_sock *dl_next; 552e6599cbSArnaldo Carvalho de Melo u16 mss; 56e6c022a4SEric Dumazet u8 num_retrans; /* number of retransmits */ 57e6c022a4SEric Dumazet u8 cookie_ts:1; /* syncookie: encode tcpopts in timestamp */ 58e6c022a4SEric Dumazet u8 num_timeout:7; /* number of timeouts */ 592e6599cbSArnaldo Carvalho de Melo u32 ts_recent; 60fa76ce73SEric Dumazet struct timer_list rsk_timer; 6172a3effaSEric Dumazet const struct request_sock_ops *rsk_ops; 622e6599cbSArnaldo Carvalho de Melo struct sock *sk; 63cd8ae852SEric Dumazet u32 *saved_syn; 644237c75cSVenkat Yekkirala u32 secid; 656b877699SVenkat Yekkirala u32 peer_secid; 662e6599cbSArnaldo Carvalho de Melo }; 672e6599cbSArnaldo Carvalho de Melo 68b1f0a0e9SFlorian Westphal static inline struct request_sock *inet_reqsk(const struct sock *sk) 69b267cdd1SEric Dumazet { 70b267cdd1SEric Dumazet return (struct request_sock *)sk; 71b267cdd1SEric Dumazet } 72b267cdd1SEric Dumazet 73b267cdd1SEric Dumazet static inline struct sock *req_to_sk(struct request_sock *req) 74b267cdd1SEric Dumazet { 75b267cdd1SEric Dumazet return (struct sock *)req; 76b267cdd1SEric Dumazet } 77b267cdd1SEric Dumazet 784e9a578eSEric Dumazet static inline struct request_sock * 79a1a5344dSEric Dumazet reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener, 80a1a5344dSEric Dumazet bool attach_listener) 812e6599cbSArnaldo Carvalho de Melo { 82e96f78abSEric Dumazet struct request_sock *req; 83e96f78abSEric Dumazet 84e96f78abSEric Dumazet req = kmem_cache_alloc(ops->slab, GFP_ATOMIC | __GFP_NOWARN); 853a5d1c0eSEric Dumazet if (!req) 863a5d1c0eSEric Dumazet return NULL; 87a1a5344dSEric Dumazet req->rsk_listener = NULL; 883a5d1c0eSEric Dumazet if (attach_listener) { 8941c6d650SReshetova, Elena if (unlikely(!refcount_inc_not_zero(&sk_listener->sk_refcnt))) { 903a5d1c0eSEric Dumazet kmem_cache_free(ops->slab, req); 913a5d1c0eSEric Dumazet return NULL; 92a1a5344dSEric Dumazet } 933a5d1c0eSEric Dumazet req->rsk_listener = sk_listener; 943a5d1c0eSEric Dumazet } 953a5d1c0eSEric Dumazet req->rsk_ops = ops; 96b267cdd1SEric Dumazet req_to_sk(req)->sk_prot = sk_listener->sk_prot; 97b267cdd1SEric Dumazet sk_node_init(&req_to_sk(req)->sk_node); 98004a5d01SEric Dumazet sk_tx_queue_clear(req_to_sk(req)); 99cd8ae852SEric Dumazet req->saved_syn = NULL; 10085f9aa75SEric Dumazet req->num_timeout = 0; 10185f9aa75SEric Dumazet req->num_retrans = 0; 10285f9aa75SEric Dumazet req->sk = NULL; 10341c6d650SReshetova, Elena refcount_set(&req->rsk_refcnt, 0); 1043a5d1c0eSEric Dumazet 1052e6599cbSArnaldo Carvalho de Melo return req; 1062e6599cbSArnaldo Carvalho de Melo } 1072e6599cbSArnaldo Carvalho de Melo 1089403cf23SGuillaume Nault static inline void __reqsk_free(struct request_sock *req) 1092e6599cbSArnaldo Carvalho de Melo { 11060236fddSArnaldo Carvalho de Melo req->rsk_ops->destructor(req); 1114e9a578eSEric Dumazet if (req->rsk_listener) 1124e9a578eSEric Dumazet sock_put(req->rsk_listener); 113cd8ae852SEric Dumazet kfree(req->saved_syn); 11413854e5aSEric Dumazet kmem_cache_free(req->rsk_ops->slab, req); 1152e6599cbSArnaldo Carvalho de Melo } 1162e6599cbSArnaldo Carvalho de Melo 1179403cf23SGuillaume Nault static inline void reqsk_free(struct request_sock *req) 1189403cf23SGuillaume Nault { 1199403cf23SGuillaume Nault WARN_ON_ONCE(refcount_read(&req->rsk_refcnt) != 0); 1209403cf23SGuillaume Nault __reqsk_free(req); 1219403cf23SGuillaume Nault } 1229403cf23SGuillaume Nault 1231e2e0117SEric Dumazet static inline void reqsk_put(struct request_sock *req) 1241e2e0117SEric Dumazet { 12541c6d650SReshetova, Elena if (refcount_dec_and_test(&req->rsk_refcnt)) 1261e2e0117SEric Dumazet reqsk_free(req); 1271e2e0117SEric Dumazet } 1280e87506fSArnaldo Carvalho de Melo 12910467163SJerry Chu /* 13010467163SJerry Chu * For a TCP Fast Open listener - 13110467163SJerry Chu * lock - protects the access to all the reqsk, which is co-owned by 13210467163SJerry Chu * the listener and the child socket. 13310467163SJerry Chu * qlen - pending TFO requests (still in TCP_SYN_RECV). 13410467163SJerry Chu * max_qlen - max TFO reqs allowed before TFO is disabled. 13510467163SJerry Chu * 13610467163SJerry Chu * XXX (TFO) - ideally these fields can be made as part of "listen_sock" 13710467163SJerry Chu * structure above. But there is some implementation difficulty due to 13810467163SJerry Chu * listen_sock being part of request_sock_queue hence will be freed when 13910467163SJerry Chu * a listener is stopped. But TFO related fields may continue to be 14010467163SJerry Chu * accessed even after a listener is closed, until its sk_refcnt drops 14110467163SJerry Chu * to 0 implying no more outstanding TFO reqs. One solution is to keep 14210467163SJerry Chu * listen_opt around until sk_refcnt drops to 0. But there is some other 14310467163SJerry Chu * complexity that needs to be resolved. E.g., a listener can be disabled 14410467163SJerry Chu * temporarily through shutdown()->tcp_disconnect(), and re-enabled later. 14510467163SJerry Chu */ 14610467163SJerry Chu struct fastopen_queue { 14710467163SJerry Chu struct request_sock *rskq_rst_head; /* Keep track of past TFO */ 14810467163SJerry Chu struct request_sock *rskq_rst_tail; /* requests that caused RST. 14910467163SJerry Chu * This is part of the defense 15010467163SJerry Chu * against spoofing attack. 15110467163SJerry Chu */ 15210467163SJerry Chu spinlock_t lock; 15310467163SJerry Chu int qlen; /* # of pending (TCP_SYN_RECV) reqs */ 15410467163SJerry Chu int max_qlen; /* != 0 iff TFO is currently enabled */ 1551fba70e5SYuchung Cheng 1561fba70e5SYuchung Cheng struct tcp_fastopen_context __rcu *ctx; /* cipher context for cookie */ 15710467163SJerry Chu }; 15810467163SJerry Chu 1590e87506fSArnaldo Carvalho de Melo /** struct request_sock_queue - queue of request_socks 1600e87506fSArnaldo Carvalho de Melo * 1610e87506fSArnaldo Carvalho de Melo * @rskq_accept_head - FIFO head of established children 1620e87506fSArnaldo Carvalho de Melo * @rskq_accept_tail - FIFO tail of established children 163295f7324SArnaldo Carvalho de Melo * @rskq_defer_accept - User waits for some data after accept() 1640e87506fSArnaldo Carvalho de Melo * 1650e87506fSArnaldo Carvalho de Melo */ 1660e87506fSArnaldo Carvalho de Melo struct request_sock_queue { 167fff1f300SEric Dumazet spinlock_t rskq_lock; 168fff1f300SEric Dumazet u8 rskq_defer_accept; 169ef547f2aSEric Dumazet 1708d2675f1SEric Dumazet u32 synflood_warned; 171aac065c5SEric Dumazet atomic_t qlen; 172aac065c5SEric Dumazet atomic_t young; 173aac065c5SEric Dumazet 1740e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_head; 1750e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_tail; 1760536fcc0SEric Dumazet struct fastopen_queue fastopenq; /* Check max_qlen != 0 to determine 1770536fcc0SEric Dumazet * if TFO is enabled. 17810467163SJerry Chu */ 1790e87506fSArnaldo Carvalho de Melo }; 1800e87506fSArnaldo Carvalho de Melo 181ef547f2aSEric Dumazet void reqsk_queue_alloc(struct request_sock_queue *queue); 1820e87506fSArnaldo Carvalho de Melo 183c0f4502aSJoe Perches void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req, 184c0f4502aSJoe Perches bool reset); 18583e3609eSArnaldo Carvalho de Melo 186fff1f300SEric Dumazet static inline bool reqsk_queue_empty(const struct request_sock_queue *queue) 1870e87506fSArnaldo Carvalho de Melo { 1880e87506fSArnaldo Carvalho de Melo return queue->rskq_accept_head == NULL; 1890e87506fSArnaldo Carvalho de Melo } 1900e87506fSArnaldo Carvalho de Melo 191fff1f300SEric Dumazet static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue, 192fff1f300SEric Dumazet struct sock *parent) 1930e87506fSArnaldo Carvalho de Melo { 194fff1f300SEric Dumazet struct request_sock *req; 1950e87506fSArnaldo Carvalho de Melo 196fff1f300SEric Dumazet spin_lock_bh(&queue->rskq_lock); 197fff1f300SEric Dumazet req = queue->rskq_accept_head; 198fff1f300SEric Dumazet if (req) { 199fff1f300SEric Dumazet sk_acceptq_removed(parent); 2000e87506fSArnaldo Carvalho de Melo queue->rskq_accept_head = req->dl_next; 2010e87506fSArnaldo Carvalho de Melo if (queue->rskq_accept_head == NULL) 2020e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail = NULL; 203fff1f300SEric Dumazet } 204fff1f300SEric Dumazet spin_unlock_bh(&queue->rskq_lock); 2050e87506fSArnaldo Carvalho de Melo return req; 2060e87506fSArnaldo Carvalho de Melo } 2070e87506fSArnaldo Carvalho de Melo 208fa76ce73SEric Dumazet static inline void reqsk_queue_removed(struct request_sock_queue *queue, 209fa76ce73SEric Dumazet const struct request_sock *req) 2100e87506fSArnaldo Carvalho de Melo { 211e6c022a4SEric Dumazet if (req->num_timeout == 0) 212aac065c5SEric Dumazet atomic_dec(&queue->young); 213aac065c5SEric Dumazet atomic_dec(&queue->qlen); 2140e87506fSArnaldo Carvalho de Melo } 2150e87506fSArnaldo Carvalho de Melo 216fa76ce73SEric Dumazet static inline void reqsk_queue_added(struct request_sock_queue *queue) 2170e87506fSArnaldo Carvalho de Melo { 218aac065c5SEric Dumazet atomic_inc(&queue->young); 219aac065c5SEric Dumazet atomic_inc(&queue->qlen); 2200e87506fSArnaldo Carvalho de Melo } 2210e87506fSArnaldo Carvalho de Melo 222463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len(const struct request_sock_queue *queue) 2230e87506fSArnaldo Carvalho de Melo { 224aac065c5SEric Dumazet return atomic_read(&queue->qlen); 2250e87506fSArnaldo Carvalho de Melo } 2260e87506fSArnaldo Carvalho de Melo 227463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len_young(const struct request_sock_queue *queue) 2280e87506fSArnaldo Carvalho de Melo { 229aac065c5SEric Dumazet return atomic_read(&queue->young); 2300e87506fSArnaldo Carvalho de Melo } 2310e87506fSArnaldo Carvalho de Melo 2322e6599cbSArnaldo Carvalho de Melo #endif /* _REQUEST_SOCK_H */ 233