12e6599cbSArnaldo Carvalho de Melo /* 22e6599cbSArnaldo Carvalho de Melo * NET Generic infrastructure for Network protocols. 32e6599cbSArnaldo Carvalho de Melo * 42e6599cbSArnaldo Carvalho de Melo * Definitions for request_sock 52e6599cbSArnaldo Carvalho de Melo * 62e6599cbSArnaldo Carvalho de Melo * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br> 72e6599cbSArnaldo Carvalho de Melo * 82e6599cbSArnaldo Carvalho de Melo * From code originally in include/net/tcp.h 92e6599cbSArnaldo Carvalho de Melo * 102e6599cbSArnaldo Carvalho de Melo * This program is free software; you can redistribute it and/or 112e6599cbSArnaldo Carvalho de Melo * modify it under the terms of the GNU General Public License 122e6599cbSArnaldo Carvalho de Melo * as published by the Free Software Foundation; either version 132e6599cbSArnaldo Carvalho de Melo * 2 of the License, or (at your option) any later version. 142e6599cbSArnaldo Carvalho de Melo */ 152e6599cbSArnaldo Carvalho de Melo #ifndef _REQUEST_SOCK_H 162e6599cbSArnaldo Carvalho de Melo #define _REQUEST_SOCK_H 172e6599cbSArnaldo Carvalho de Melo 182e6599cbSArnaldo Carvalho de Melo #include <linux/slab.h> 190e87506fSArnaldo Carvalho de Melo #include <linux/spinlock.h> 202e6599cbSArnaldo Carvalho de Melo #include <linux/types.h> 21547b792cSIlpo Järvinen #include <linux/bug.h> 220e87506fSArnaldo Carvalho de Melo 232e6599cbSArnaldo Carvalho de Melo #include <net/sock.h> 242e6599cbSArnaldo Carvalho de Melo 2560236fddSArnaldo Carvalho de Melo struct request_sock; 262e6599cbSArnaldo Carvalho de Melo struct sk_buff; 272e6599cbSArnaldo Carvalho de Melo struct dst_entry; 282e6599cbSArnaldo Carvalho de Melo struct proto; 292e6599cbSArnaldo Carvalho de Melo 3060236fddSArnaldo Carvalho de Melo struct request_sock_ops { 312e6599cbSArnaldo Carvalho de Melo int family; 322e6599cbSArnaldo Carvalho de Melo int obj_size; 33e18b890bSChristoph Lameter struct kmem_cache *slab; 347e56b5d6SCatalin Marinas char *slab_name; 35ea3bea3aSEric Dumazet int (*rtx_syn_ack)(const struct sock *sk, 361a2c6181SChristoph Paasch struct request_sock *req); 37a00e7444SEric Dumazet void (*send_ack)(const struct sock *sk, struct sk_buff *skb, 3860236fddSArnaldo Carvalho de Melo struct request_sock *req); 39a00e7444SEric Dumazet void (*send_reset)(const struct sock *sk, 40cfb6eeb4SYOSHIFUJI Hideaki struct sk_buff *skb); 4160236fddSArnaldo Carvalho de Melo void (*destructor)(struct request_sock *req); 4242cb80a2SEric Dumazet void (*syn_ack_timeout)(const struct request_sock *req); 432e6599cbSArnaldo Carvalho de Melo }; 442e6599cbSArnaldo Carvalho de Melo 451b70e977SEric Dumazet int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req); 46e6c022a4SEric Dumazet 4760236fddSArnaldo Carvalho de Melo /* struct request_sock - mini sock to represent a connection request 482e6599cbSArnaldo Carvalho de Melo */ 4960236fddSArnaldo Carvalho de Melo struct request_sock { 50634fb979SEric Dumazet struct sock_common __req_common; 511e2e0117SEric Dumazet #define rsk_refcnt __req_common.skc_refcnt 5252452c54SEric Dumazet #define rsk_hash __req_common.skc_hash 531e2e0117SEric Dumazet 543fb62c5dSEric Dumazet struct request_sock *dl_next; 554e9a578eSEric Dumazet struct sock *rsk_listener; 562e6599cbSArnaldo Carvalho de Melo u16 mss; 57e6c022a4SEric Dumazet u8 num_retrans; /* number of retransmits */ 58e6c022a4SEric Dumazet u8 cookie_ts:1; /* syncookie: encode tcpopts in timestamp */ 59e6c022a4SEric Dumazet u8 num_timeout:7; /* number of timeouts */ 602e6599cbSArnaldo Carvalho de Melo /* The following two fields can be easily recomputed I think -AK */ 612e6599cbSArnaldo Carvalho de Melo u32 window_clamp; /* window clamp at creation time */ 622e6599cbSArnaldo Carvalho de Melo u32 rcv_wnd; /* rcv_wnd offered first time */ 632e6599cbSArnaldo Carvalho de Melo u32 ts_recent; 64fa76ce73SEric Dumazet struct timer_list rsk_timer; 6572a3effaSEric Dumazet const struct request_sock_ops *rsk_ops; 662e6599cbSArnaldo Carvalho de Melo struct sock *sk; 67cd8ae852SEric Dumazet u32 *saved_syn; 684237c75cSVenkat Yekkirala u32 secid; 696b877699SVenkat Yekkirala u32 peer_secid; 702e6599cbSArnaldo Carvalho de Melo }; 712e6599cbSArnaldo Carvalho de Melo 724e9a578eSEric Dumazet static inline struct request_sock * 734e9a578eSEric Dumazet reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener) 742e6599cbSArnaldo Carvalho de Melo { 7554e6ecb2SChristoph Lameter struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC); 762e6599cbSArnaldo Carvalho de Melo 774e9a578eSEric Dumazet if (req) { 7860236fddSArnaldo Carvalho de Melo req->rsk_ops = ops; 794e9a578eSEric Dumazet sock_hold(sk_listener); 804e9a578eSEric Dumazet req->rsk_listener = sk_listener; 81cd8ae852SEric Dumazet req->saved_syn = NULL; 820470c8caSEric Dumazet /* Following is temporary. It is coupled with debugging 830470c8caSEric Dumazet * helpers in reqsk_put() & reqsk_free() 840470c8caSEric Dumazet */ 850470c8caSEric Dumazet atomic_set(&req->rsk_refcnt, 0); 864e9a578eSEric Dumazet } 872e6599cbSArnaldo Carvalho de Melo return req; 882e6599cbSArnaldo Carvalho de Melo } 892e6599cbSArnaldo Carvalho de Melo 9041b822c5SEric Dumazet static inline struct request_sock *inet_reqsk(struct sock *sk) 9141b822c5SEric Dumazet { 9241b822c5SEric Dumazet return (struct request_sock *)sk; 9341b822c5SEric Dumazet } 9441b822c5SEric Dumazet 9508d2cc3bSEric Dumazet static inline struct sock *req_to_sk(struct request_sock *req) 9608d2cc3bSEric Dumazet { 9708d2cc3bSEric Dumazet return (struct sock *)req; 9808d2cc3bSEric Dumazet } 9908d2cc3bSEric Dumazet 10060236fddSArnaldo Carvalho de Melo static inline void reqsk_free(struct request_sock *req) 1012e6599cbSArnaldo Carvalho de Melo { 10213854e5aSEric Dumazet /* temporary debugging */ 10313854e5aSEric Dumazet WARN_ON_ONCE(atomic_read(&req->rsk_refcnt) != 0); 10413854e5aSEric Dumazet 10560236fddSArnaldo Carvalho de Melo req->rsk_ops->destructor(req); 1064e9a578eSEric Dumazet if (req->rsk_listener) 1074e9a578eSEric Dumazet sock_put(req->rsk_listener); 108cd8ae852SEric Dumazet kfree(req->saved_syn); 10913854e5aSEric Dumazet kmem_cache_free(req->rsk_ops->slab, req); 1102e6599cbSArnaldo Carvalho de Melo } 1112e6599cbSArnaldo Carvalho de Melo 1121e2e0117SEric Dumazet static inline void reqsk_put(struct request_sock *req) 1131e2e0117SEric Dumazet { 1141e2e0117SEric Dumazet if (atomic_dec_and_test(&req->rsk_refcnt)) 1151e2e0117SEric Dumazet reqsk_free(req); 1161e2e0117SEric Dumazet } 1171e2e0117SEric Dumazet 1180e87506fSArnaldo Carvalho de Melo extern int sysctl_max_syn_backlog; 1190e87506fSArnaldo Carvalho de Melo 1202ad69c55SArnaldo Carvalho de Melo /** struct listen_sock - listen state 1210e87506fSArnaldo Carvalho de Melo * 1220e87506fSArnaldo Carvalho de Melo * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs 1230e87506fSArnaldo Carvalho de Melo */ 1242ad69c55SArnaldo Carvalho de Melo struct listen_sock { 125aac065c5SEric Dumazet u32 max_qlen_log; 1260e87506fSArnaldo Carvalho de Melo u32 hash_rnd; 12783e3609eSArnaldo Carvalho de Melo u32 nr_table_entries; 1280e87506fSArnaldo Carvalho de Melo struct request_sock *syn_table[0]; 1290e87506fSArnaldo Carvalho de Melo }; 1300e87506fSArnaldo Carvalho de Melo 13110467163SJerry Chu /* 13210467163SJerry Chu * For a TCP Fast Open listener - 13310467163SJerry Chu * lock - protects the access to all the reqsk, which is co-owned by 13410467163SJerry Chu * the listener and the child socket. 13510467163SJerry Chu * qlen - pending TFO requests (still in TCP_SYN_RECV). 13610467163SJerry Chu * max_qlen - max TFO reqs allowed before TFO is disabled. 13710467163SJerry Chu * 13810467163SJerry Chu * XXX (TFO) - ideally these fields can be made as part of "listen_sock" 13910467163SJerry Chu * structure above. But there is some implementation difficulty due to 14010467163SJerry Chu * listen_sock being part of request_sock_queue hence will be freed when 14110467163SJerry Chu * a listener is stopped. But TFO related fields may continue to be 14210467163SJerry Chu * accessed even after a listener is closed, until its sk_refcnt drops 14310467163SJerry Chu * to 0 implying no more outstanding TFO reqs. One solution is to keep 14410467163SJerry Chu * listen_opt around until sk_refcnt drops to 0. But there is some other 14510467163SJerry Chu * complexity that needs to be resolved. E.g., a listener can be disabled 14610467163SJerry Chu * temporarily through shutdown()->tcp_disconnect(), and re-enabled later. 14710467163SJerry Chu */ 14810467163SJerry Chu struct fastopen_queue { 14910467163SJerry Chu struct request_sock *rskq_rst_head; /* Keep track of past TFO */ 15010467163SJerry Chu struct request_sock *rskq_rst_tail; /* requests that caused RST. 15110467163SJerry Chu * This is part of the defense 15210467163SJerry Chu * against spoofing attack. 15310467163SJerry Chu */ 15410467163SJerry Chu spinlock_t lock; 15510467163SJerry Chu int qlen; /* # of pending (TCP_SYN_RECV) reqs */ 15610467163SJerry Chu int max_qlen; /* != 0 iff TFO is currently enabled */ 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 * @syn_wait_lock - serializer 1650e87506fSArnaldo Carvalho de Melo * 1660e87506fSArnaldo Carvalho de Melo * %syn_wait_lock is necessary only to avoid proc interface having to grab the main 1670e87506fSArnaldo Carvalho de Melo * lock sock while browsing the listening hash (otherwise it's deadlock prone). 1680e87506fSArnaldo Carvalho de Melo * 1690e87506fSArnaldo Carvalho de Melo */ 1700e87506fSArnaldo Carvalho de Melo struct request_sock_queue { 171fff1f300SEric Dumazet spinlock_t rskq_lock; 172fff1f300SEric Dumazet u8 rskq_defer_accept; 1738d2675f1SEric Dumazet u32 synflood_warned; 174fff1f300SEric Dumazet 175aac065c5SEric Dumazet atomic_t qlen; 176aac065c5SEric Dumazet atomic_t young; 177aac065c5SEric Dumazet 1780e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_head; 1790e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_tail; 1802ad69c55SArnaldo Carvalho de Melo struct listen_sock *listen_opt; 1810536fcc0SEric Dumazet struct fastopen_queue fastopenq; /* Check max_qlen != 0 to determine 1820536fcc0SEric Dumazet * if TFO is enabled. 18310467163SJerry Chu */ 184fa76ce73SEric Dumazet 185fa76ce73SEric Dumazet /* temporary alignment, our goal is to get rid of this lock */ 186b2827053SEric Dumazet spinlock_t syn_wait_lock ____cacheline_aligned_in_smp; 1870e87506fSArnaldo Carvalho de Melo }; 1880e87506fSArnaldo Carvalho de Melo 189c0f4502aSJoe Perches int reqsk_queue_alloc(struct request_sock_queue *queue, 19072a3effaSEric Dumazet unsigned int nr_table_entries); 1910e87506fSArnaldo Carvalho de Melo 192c0f4502aSJoe Perches void __reqsk_queue_destroy(struct request_sock_queue *queue); 193c0f4502aSJoe Perches void reqsk_queue_destroy(struct request_sock_queue *queue); 194c0f4502aSJoe Perches void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req, 195c0f4502aSJoe Perches bool reset); 19683e3609eSArnaldo Carvalho de Melo 197fff1f300SEric Dumazet static inline bool reqsk_queue_empty(const struct request_sock_queue *queue) 1980e87506fSArnaldo Carvalho de Melo { 1990e87506fSArnaldo Carvalho de Melo return queue->rskq_accept_head == NULL; 2000e87506fSArnaldo Carvalho de Melo } 2010e87506fSArnaldo Carvalho de Melo 2020e87506fSArnaldo Carvalho de Melo static inline void reqsk_queue_add(struct request_sock_queue *queue, 2030e87506fSArnaldo Carvalho de Melo struct request_sock *req, 2040e87506fSArnaldo Carvalho de Melo struct sock *parent, 2050e87506fSArnaldo Carvalho de Melo struct sock *child) 2060e87506fSArnaldo Carvalho de Melo { 207fff1f300SEric Dumazet spin_lock(&queue->rskq_lock); 2080e87506fSArnaldo Carvalho de Melo req->sk = child; 2090e87506fSArnaldo Carvalho de Melo sk_acceptq_added(parent); 2100e87506fSArnaldo Carvalho de Melo 2110e87506fSArnaldo Carvalho de Melo if (queue->rskq_accept_head == NULL) 2120e87506fSArnaldo Carvalho de Melo queue->rskq_accept_head = req; 2130e87506fSArnaldo Carvalho de Melo else 2140e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail->dl_next = req; 2150e87506fSArnaldo Carvalho de Melo 2160e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail = req; 2170e87506fSArnaldo Carvalho de Melo req->dl_next = NULL; 218fff1f300SEric Dumazet spin_unlock(&queue->rskq_lock); 2190e87506fSArnaldo Carvalho de Melo } 2200e87506fSArnaldo Carvalho de Melo 221fff1f300SEric Dumazet static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue, 222fff1f300SEric Dumazet struct sock *parent) 2230e87506fSArnaldo Carvalho de Melo { 224fff1f300SEric Dumazet struct request_sock *req; 2250e87506fSArnaldo Carvalho de Melo 226fff1f300SEric Dumazet spin_lock_bh(&queue->rskq_lock); 227fff1f300SEric Dumazet req = queue->rskq_accept_head; 228fff1f300SEric Dumazet if (req) { 229fff1f300SEric Dumazet sk_acceptq_removed(parent); 2300e87506fSArnaldo Carvalho de Melo queue->rskq_accept_head = req->dl_next; 2310e87506fSArnaldo Carvalho de Melo if (queue->rskq_accept_head == NULL) 2320e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail = NULL; 233fff1f300SEric Dumazet } 234fff1f300SEric Dumazet spin_unlock_bh(&queue->rskq_lock); 2350e87506fSArnaldo Carvalho de Melo return req; 2360e87506fSArnaldo Carvalho de Melo } 2370e87506fSArnaldo Carvalho de Melo 238fa76ce73SEric Dumazet static inline void reqsk_queue_removed(struct request_sock_queue *queue, 239fa76ce73SEric Dumazet const struct request_sock *req) 2400e87506fSArnaldo Carvalho de Melo { 241e6c022a4SEric Dumazet if (req->num_timeout == 0) 242aac065c5SEric Dumazet atomic_dec(&queue->young); 243aac065c5SEric Dumazet atomic_dec(&queue->qlen); 2440e87506fSArnaldo Carvalho de Melo } 2450e87506fSArnaldo Carvalho de Melo 246fa76ce73SEric Dumazet static inline void reqsk_queue_added(struct request_sock_queue *queue) 2470e87506fSArnaldo Carvalho de Melo { 248aac065c5SEric Dumazet atomic_inc(&queue->young); 249aac065c5SEric Dumazet atomic_inc(&queue->qlen); 2500e87506fSArnaldo Carvalho de Melo } 2510e87506fSArnaldo Carvalho de Melo 252463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len(const struct request_sock_queue *queue) 2530e87506fSArnaldo Carvalho de Melo { 254aac065c5SEric Dumazet return atomic_read(&queue->qlen); 2550e87506fSArnaldo Carvalho de Melo } 2560e87506fSArnaldo Carvalho de Melo 257463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len_young(const struct request_sock_queue *queue) 2580e87506fSArnaldo Carvalho de Melo { 259aac065c5SEric Dumazet return atomic_read(&queue->young); 2600e87506fSArnaldo Carvalho de Melo } 2610e87506fSArnaldo Carvalho de Melo 262463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_is_full(const struct request_sock_queue *queue) 2630e87506fSArnaldo Carvalho de Melo { 264fa76ce73SEric Dumazet return reqsk_queue_len(queue) >> queue->listen_opt->max_qlen_log; 2650e87506fSArnaldo Carvalho de Melo } 2660e87506fSArnaldo Carvalho de Melo 267fa76ce73SEric Dumazet void reqsk_queue_hash_req(struct request_sock_queue *queue, 2680e87506fSArnaldo Carvalho de Melo u32 hash, struct request_sock *req, 269fa76ce73SEric Dumazet unsigned long timeout); 2700e87506fSArnaldo Carvalho de Melo 2712e6599cbSArnaldo Carvalho de Melo #endif /* _REQUEST_SOCK_H */ 272