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; 352e6599cbSArnaldo Carvalho de Melo int (*rtx_syn_ack)(struct sock *sk, 361a2c6181SChristoph Paasch struct request_sock *req); 376edafaafSGui Jianfeng void (*send_ack)(struct sock *sk, struct sk_buff *skb, 3860236fddSArnaldo Carvalho de Melo struct request_sock *req); 39cfb6eeb4SYOSHIFUJI Hideaki void (*send_reset)(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 45c0f4502aSJoe Perches int inet_rtx_syn_ack(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; 674237c75cSVenkat Yekkirala u32 secid; 686b877699SVenkat Yekkirala u32 peer_secid; 692e6599cbSArnaldo Carvalho de Melo }; 702e6599cbSArnaldo Carvalho de Melo 714e9a578eSEric Dumazet static inline struct request_sock * 724e9a578eSEric Dumazet reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener) 732e6599cbSArnaldo Carvalho de Melo { 7454e6ecb2SChristoph Lameter struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC); 752e6599cbSArnaldo Carvalho de Melo 764e9a578eSEric Dumazet if (req) { 7760236fddSArnaldo Carvalho de Melo req->rsk_ops = ops; 784e9a578eSEric Dumazet sock_hold(sk_listener); 794e9a578eSEric Dumazet req->rsk_listener = sk_listener; 800470c8caSEric Dumazet 810470c8caSEric Dumazet /* Following is temporary. It is coupled with debugging 820470c8caSEric Dumazet * helpers in reqsk_put() & reqsk_free() 830470c8caSEric Dumazet */ 840470c8caSEric Dumazet atomic_set(&req->rsk_refcnt, 0); 854e9a578eSEric Dumazet } 862e6599cbSArnaldo Carvalho de Melo return req; 872e6599cbSArnaldo Carvalho de Melo } 882e6599cbSArnaldo Carvalho de Melo 8941b822c5SEric Dumazet static inline struct request_sock *inet_reqsk(struct sock *sk) 9041b822c5SEric Dumazet { 9141b822c5SEric Dumazet return (struct request_sock *)sk; 9241b822c5SEric Dumazet } 9341b822c5SEric Dumazet 9408d2cc3bSEric Dumazet static inline struct sock *req_to_sk(struct request_sock *req) 9508d2cc3bSEric Dumazet { 9608d2cc3bSEric Dumazet return (struct sock *)req; 9708d2cc3bSEric Dumazet } 9808d2cc3bSEric Dumazet 9960236fddSArnaldo Carvalho de Melo static inline void reqsk_free(struct request_sock *req) 1002e6599cbSArnaldo Carvalho de Melo { 10113854e5aSEric Dumazet /* temporary debugging */ 10213854e5aSEric Dumazet WARN_ON_ONCE(atomic_read(&req->rsk_refcnt) != 0); 10313854e5aSEric Dumazet 10460236fddSArnaldo Carvalho de Melo req->rsk_ops->destructor(req); 1054e9a578eSEric Dumazet if (req->rsk_listener) 1064e9a578eSEric Dumazet sock_put(req->rsk_listener); 10713854e5aSEric Dumazet kmem_cache_free(req->rsk_ops->slab, req); 1082e6599cbSArnaldo Carvalho de Melo } 1092e6599cbSArnaldo Carvalho de Melo 1101e2e0117SEric Dumazet static inline void reqsk_put(struct request_sock *req) 1111e2e0117SEric Dumazet { 1121e2e0117SEric Dumazet if (atomic_dec_and_test(&req->rsk_refcnt)) 1131e2e0117SEric Dumazet reqsk_free(req); 1141e2e0117SEric Dumazet } 1151e2e0117SEric Dumazet 1160e87506fSArnaldo Carvalho de Melo extern int sysctl_max_syn_backlog; 1170e87506fSArnaldo Carvalho de Melo 1182ad69c55SArnaldo Carvalho de Melo /** struct listen_sock - listen state 1190e87506fSArnaldo Carvalho de Melo * 1200e87506fSArnaldo Carvalho de Melo * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs 1210e87506fSArnaldo Carvalho de Melo */ 1222ad69c55SArnaldo Carvalho de Melo struct listen_sock { 123fa76ce73SEric Dumazet int qlen_inc; /* protected by listener lock */ 124fa76ce73SEric Dumazet int young_inc;/* protected by listener lock */ 125fa76ce73SEric Dumazet 126fa76ce73SEric Dumazet /* following fields can be updated by timer */ 127fa76ce73SEric Dumazet atomic_t qlen_dec; /* qlen = qlen_inc - qlen_dec */ 128fa76ce73SEric Dumazet atomic_t young_dec; 129fa76ce73SEric Dumazet 130fa76ce73SEric Dumazet u8 max_qlen_log ____cacheline_aligned_in_smp; 131946cedccSEric Dumazet u8 synflood_warned; 132946cedccSEric Dumazet /* 2 bytes hole, try to use */ 1330e87506fSArnaldo Carvalho de Melo u32 hash_rnd; 13483e3609eSArnaldo Carvalho de Melo u32 nr_table_entries; 1350e87506fSArnaldo Carvalho de Melo struct request_sock *syn_table[0]; 1360e87506fSArnaldo Carvalho de Melo }; 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 */ 16410467163SJerry Chu }; 16510467163SJerry Chu 1660e87506fSArnaldo Carvalho de Melo /** struct request_sock_queue - queue of request_socks 1670e87506fSArnaldo Carvalho de Melo * 1680e87506fSArnaldo Carvalho de Melo * @rskq_accept_head - FIFO head of established children 1690e87506fSArnaldo Carvalho de Melo * @rskq_accept_tail - FIFO tail of established children 170295f7324SArnaldo Carvalho de Melo * @rskq_defer_accept - User waits for some data after accept() 1710e87506fSArnaldo Carvalho de Melo * @syn_wait_lock - serializer 1720e87506fSArnaldo Carvalho de Melo * 1730e87506fSArnaldo Carvalho de Melo * %syn_wait_lock is necessary only to avoid proc interface having to grab the main 1740e87506fSArnaldo Carvalho de Melo * lock sock while browsing the listening hash (otherwise it's deadlock prone). 1750e87506fSArnaldo Carvalho de Melo * 1760e87506fSArnaldo Carvalho de Melo */ 1770e87506fSArnaldo Carvalho de Melo struct request_sock_queue { 1780e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_head; 1790e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_tail; 180ec0a1966SDavid S. Miller u8 rskq_defer_accept; 1812ad69c55SArnaldo Carvalho de Melo struct listen_sock *listen_opt; 18210467163SJerry Chu struct fastopen_queue *fastopenq; /* This is non-NULL iff TFO has been 18310467163SJerry Chu * enabled on this listener. Check 18410467163SJerry Chu * max_qlen != 0 in fastopen_queue 18510467163SJerry Chu * to determine if TFO is enabled 18610467163SJerry Chu * right at this moment. 18710467163SJerry Chu */ 188fa76ce73SEric Dumazet 189fa76ce73SEric Dumazet /* temporary alignment, our goal is to get rid of this lock */ 190b2827053SEric Dumazet spinlock_t syn_wait_lock ____cacheline_aligned_in_smp; 1910e87506fSArnaldo Carvalho de Melo }; 1920e87506fSArnaldo Carvalho de Melo 193c0f4502aSJoe Perches int reqsk_queue_alloc(struct request_sock_queue *queue, 19472a3effaSEric Dumazet unsigned int nr_table_entries); 1950e87506fSArnaldo Carvalho de Melo 196c0f4502aSJoe Perches void __reqsk_queue_destroy(struct request_sock_queue *queue); 197c0f4502aSJoe Perches void reqsk_queue_destroy(struct request_sock_queue *queue); 198c0f4502aSJoe Perches void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req, 199c0f4502aSJoe Perches bool reset); 20083e3609eSArnaldo Carvalho de Melo 2010e87506fSArnaldo Carvalho de Melo static inline struct request_sock * 2020e87506fSArnaldo Carvalho de Melo reqsk_queue_yank_acceptq(struct request_sock_queue *queue) 2030e87506fSArnaldo Carvalho de Melo { 2040e87506fSArnaldo Carvalho de Melo struct request_sock *req = queue->rskq_accept_head; 2050e87506fSArnaldo Carvalho de Melo 2063eb4801dSNorbert Kiesel queue->rskq_accept_head = NULL; 2070e87506fSArnaldo Carvalho de Melo return req; 2080e87506fSArnaldo Carvalho de Melo } 2090e87506fSArnaldo Carvalho de Melo 2100e87506fSArnaldo Carvalho de Melo static inline int reqsk_queue_empty(struct request_sock_queue *queue) 2110e87506fSArnaldo Carvalho de Melo { 2120e87506fSArnaldo Carvalho de Melo return queue->rskq_accept_head == NULL; 2130e87506fSArnaldo Carvalho de Melo } 2140e87506fSArnaldo Carvalho de Melo 2150e87506fSArnaldo Carvalho de Melo static inline void reqsk_queue_unlink(struct request_sock_queue *queue, 21652452c54SEric Dumazet struct request_sock *req) 2170e87506fSArnaldo Carvalho de Melo { 21852452c54SEric Dumazet struct listen_sock *lopt = queue->listen_opt; 21952452c54SEric Dumazet struct request_sock **prev; 22052452c54SEric Dumazet 221b2827053SEric Dumazet spin_lock(&queue->syn_wait_lock); 222fa76ce73SEric Dumazet 22352452c54SEric Dumazet prev = &lopt->syn_table[req->rsk_hash]; 22452452c54SEric Dumazet while (*prev != req) 22552452c54SEric Dumazet prev = &(*prev)->dl_next; 22652452c54SEric Dumazet *prev = req->dl_next; 227fa76ce73SEric Dumazet 228b2827053SEric Dumazet spin_unlock(&queue->syn_wait_lock); 229fa76ce73SEric Dumazet if (del_timer(&req->rsk_timer)) 230fa76ce73SEric Dumazet reqsk_put(req); 2310e87506fSArnaldo Carvalho de Melo } 2320e87506fSArnaldo Carvalho de Melo 2330e87506fSArnaldo Carvalho de Melo static inline void reqsk_queue_add(struct request_sock_queue *queue, 2340e87506fSArnaldo Carvalho de Melo struct request_sock *req, 2350e87506fSArnaldo Carvalho de Melo struct sock *parent, 2360e87506fSArnaldo Carvalho de Melo struct sock *child) 2370e87506fSArnaldo Carvalho de Melo { 2380e87506fSArnaldo Carvalho de Melo req->sk = child; 2390e87506fSArnaldo Carvalho de Melo sk_acceptq_added(parent); 2400e87506fSArnaldo Carvalho de Melo 2410e87506fSArnaldo Carvalho de Melo if (queue->rskq_accept_head == NULL) 2420e87506fSArnaldo Carvalho de Melo queue->rskq_accept_head = req; 2430e87506fSArnaldo Carvalho de Melo else 2440e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail->dl_next = req; 2450e87506fSArnaldo Carvalho de Melo 2460e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail = req; 2470e87506fSArnaldo Carvalho de Melo req->dl_next = NULL; 2480e87506fSArnaldo Carvalho de Melo } 2490e87506fSArnaldo Carvalho de Melo 2500e87506fSArnaldo Carvalho de Melo static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue) 2510e87506fSArnaldo Carvalho de Melo { 2520e87506fSArnaldo Carvalho de Melo struct request_sock *req = queue->rskq_accept_head; 2530e87506fSArnaldo Carvalho de Melo 254547b792cSIlpo Järvinen WARN_ON(req == NULL); 2550e87506fSArnaldo Carvalho de Melo 2560e87506fSArnaldo Carvalho de Melo queue->rskq_accept_head = req->dl_next; 2570e87506fSArnaldo Carvalho de Melo if (queue->rskq_accept_head == NULL) 2580e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail = NULL; 2590e87506fSArnaldo Carvalho de Melo 2600e87506fSArnaldo Carvalho de Melo return req; 2610e87506fSArnaldo Carvalho de Melo } 2620e87506fSArnaldo Carvalho de Melo 263fa76ce73SEric Dumazet static inline void reqsk_queue_removed(struct request_sock_queue *queue, 264fa76ce73SEric Dumazet const struct request_sock *req) 2650e87506fSArnaldo Carvalho de Melo { 2662ad69c55SArnaldo Carvalho de Melo struct listen_sock *lopt = queue->listen_opt; 2670e87506fSArnaldo Carvalho de Melo 268e6c022a4SEric Dumazet if (req->num_timeout == 0) 269fa76ce73SEric Dumazet atomic_inc(&lopt->young_dec); 270fa76ce73SEric Dumazet atomic_inc(&lopt->qlen_dec); 2710e87506fSArnaldo Carvalho de Melo } 2720e87506fSArnaldo Carvalho de Melo 273fa76ce73SEric Dumazet static inline void reqsk_queue_added(struct request_sock_queue *queue) 2740e87506fSArnaldo Carvalho de Melo { 2752ad69c55SArnaldo Carvalho de Melo struct listen_sock *lopt = queue->listen_opt; 2760e87506fSArnaldo Carvalho de Melo 277fa76ce73SEric Dumazet lopt->young_inc++; 278fa76ce73SEric Dumazet lopt->qlen_inc++; 279fa76ce73SEric Dumazet } 280fa76ce73SEric Dumazet 281fa76ce73SEric Dumazet static inline int listen_sock_qlen(const struct listen_sock *lopt) 282fa76ce73SEric Dumazet { 283fa76ce73SEric Dumazet return lopt->qlen_inc - atomic_read(&lopt->qlen_dec); 284fa76ce73SEric Dumazet } 285fa76ce73SEric Dumazet 286fa76ce73SEric Dumazet static inline int listen_sock_young(const struct listen_sock *lopt) 287fa76ce73SEric Dumazet { 288fa76ce73SEric Dumazet return lopt->young_inc - atomic_read(&lopt->young_dec); 2890e87506fSArnaldo Carvalho de Melo } 2900e87506fSArnaldo Carvalho de Melo 291463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len(const struct request_sock_queue *queue) 2920e87506fSArnaldo Carvalho de Melo { 293fa76ce73SEric Dumazet const struct listen_sock *lopt = queue->listen_opt; 294fa76ce73SEric Dumazet 295fa76ce73SEric Dumazet return lopt ? listen_sock_qlen(lopt) : 0; 2960e87506fSArnaldo Carvalho de Melo } 2970e87506fSArnaldo Carvalho de Melo 298463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len_young(const struct request_sock_queue *queue) 2990e87506fSArnaldo Carvalho de Melo { 300fa76ce73SEric Dumazet return listen_sock_young(queue->listen_opt); 3010e87506fSArnaldo Carvalho de Melo } 3020e87506fSArnaldo Carvalho de Melo 303463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_is_full(const struct request_sock_queue *queue) 3040e87506fSArnaldo Carvalho de Melo { 305fa76ce73SEric Dumazet return reqsk_queue_len(queue) >> queue->listen_opt->max_qlen_log; 3060e87506fSArnaldo Carvalho de Melo } 3070e87506fSArnaldo Carvalho de Melo 308fa76ce73SEric Dumazet void reqsk_queue_hash_req(struct request_sock_queue *queue, 3090e87506fSArnaldo Carvalho de Melo u32 hash, struct request_sock *req, 310fa76ce73SEric Dumazet unsigned long timeout); 3110e87506fSArnaldo Carvalho de Melo 3122e6599cbSArnaldo Carvalho de Melo #endif /* _REQUEST_SOCK_H */ 313