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); 4272659eccSOctavian Purdila void (*syn_ack_timeout)(struct sock *sk, 4372659eccSOctavian Purdila struct request_sock *req); 442e6599cbSArnaldo Carvalho de Melo }; 452e6599cbSArnaldo Carvalho de Melo 46c0f4502aSJoe Perches int inet_rtx_syn_ack(struct sock *parent, struct request_sock *req); 47e6c022a4SEric Dumazet 4860236fddSArnaldo Carvalho de Melo /* struct request_sock - mini sock to represent a connection request 492e6599cbSArnaldo Carvalho de Melo */ 5060236fddSArnaldo Carvalho de Melo struct request_sock { 51634fb979SEric Dumazet struct sock_common __req_common; 521e2e0117SEric Dumazet #define rsk_refcnt __req_common.skc_refcnt 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; 642e6599cbSArnaldo Carvalho de Melo unsigned long expires; 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 { 11213854e5aSEric Dumazet /* temporary debugging, until req sock are put into ehash table */ 11313854e5aSEric Dumazet WARN_ON_ONCE(atomic_read(&req->rsk_refcnt) != 1); 11413854e5aSEric Dumazet 1151e2e0117SEric Dumazet if (atomic_dec_and_test(&req->rsk_refcnt)) 1161e2e0117SEric Dumazet reqsk_free(req); 1171e2e0117SEric Dumazet } 1181e2e0117SEric Dumazet 1190e87506fSArnaldo Carvalho de Melo extern int sysctl_max_syn_backlog; 1200e87506fSArnaldo Carvalho de Melo 1212ad69c55SArnaldo Carvalho de Melo /** struct listen_sock - listen state 1220e87506fSArnaldo Carvalho de Melo * 1230e87506fSArnaldo Carvalho de Melo * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs 1240e87506fSArnaldo Carvalho de Melo */ 1252ad69c55SArnaldo Carvalho de Melo struct listen_sock { 1260e87506fSArnaldo Carvalho de Melo u8 max_qlen_log; 127946cedccSEric Dumazet u8 synflood_warned; 128946cedccSEric Dumazet /* 2 bytes hole, try to use */ 1290e87506fSArnaldo Carvalho de Melo int qlen; 1300e87506fSArnaldo Carvalho de Melo int qlen_young; 1310e87506fSArnaldo Carvalho de Melo int clock_hand; 1320e87506fSArnaldo Carvalho de Melo u32 hash_rnd; 13383e3609eSArnaldo Carvalho de Melo u32 nr_table_entries; 1340e87506fSArnaldo Carvalho de Melo struct request_sock *syn_table[0]; 1350e87506fSArnaldo Carvalho de Melo }; 1360e87506fSArnaldo Carvalho de Melo 13710467163SJerry Chu /* 13810467163SJerry Chu * For a TCP Fast Open listener - 13910467163SJerry Chu * lock - protects the access to all the reqsk, which is co-owned by 14010467163SJerry Chu * the listener and the child socket. 14110467163SJerry Chu * qlen - pending TFO requests (still in TCP_SYN_RECV). 14210467163SJerry Chu * max_qlen - max TFO reqs allowed before TFO is disabled. 14310467163SJerry Chu * 14410467163SJerry Chu * XXX (TFO) - ideally these fields can be made as part of "listen_sock" 14510467163SJerry Chu * structure above. But there is some implementation difficulty due to 14610467163SJerry Chu * listen_sock being part of request_sock_queue hence will be freed when 14710467163SJerry Chu * a listener is stopped. But TFO related fields may continue to be 14810467163SJerry Chu * accessed even after a listener is closed, until its sk_refcnt drops 14910467163SJerry Chu * to 0 implying no more outstanding TFO reqs. One solution is to keep 15010467163SJerry Chu * listen_opt around until sk_refcnt drops to 0. But there is some other 15110467163SJerry Chu * complexity that needs to be resolved. E.g., a listener can be disabled 15210467163SJerry Chu * temporarily through shutdown()->tcp_disconnect(), and re-enabled later. 15310467163SJerry Chu */ 15410467163SJerry Chu struct fastopen_queue { 15510467163SJerry Chu struct request_sock *rskq_rst_head; /* Keep track of past TFO */ 15610467163SJerry Chu struct request_sock *rskq_rst_tail; /* requests that caused RST. 15710467163SJerry Chu * This is part of the defense 15810467163SJerry Chu * against spoofing attack. 15910467163SJerry Chu */ 16010467163SJerry Chu spinlock_t lock; 16110467163SJerry Chu int qlen; /* # of pending (TCP_SYN_RECV) reqs */ 16210467163SJerry Chu int max_qlen; /* != 0 iff TFO is currently enabled */ 16310467163SJerry Chu }; 16410467163SJerry Chu 1650e87506fSArnaldo Carvalho de Melo /** struct request_sock_queue - queue of request_socks 1660e87506fSArnaldo Carvalho de Melo * 1670e87506fSArnaldo Carvalho de Melo * @rskq_accept_head - FIFO head of established children 1680e87506fSArnaldo Carvalho de Melo * @rskq_accept_tail - FIFO tail of established children 169295f7324SArnaldo Carvalho de Melo * @rskq_defer_accept - User waits for some data after accept() 1700e87506fSArnaldo Carvalho de Melo * @syn_wait_lock - serializer 1710e87506fSArnaldo Carvalho de Melo * 1720e87506fSArnaldo Carvalho de Melo * %syn_wait_lock is necessary only to avoid proc interface having to grab the main 1730e87506fSArnaldo Carvalho de Melo * lock sock while browsing the listening hash (otherwise it's deadlock prone). 1740e87506fSArnaldo Carvalho de Melo * 1750e87506fSArnaldo Carvalho de Melo * This lock is acquired in read mode only from listening_get_next() seq_file 1760e87506fSArnaldo Carvalho de Melo * op and it's acquired in write mode _only_ from code that is actively 1770e87506fSArnaldo Carvalho de Melo * changing rskq_accept_head. All readers that are holding the master sock lock 1780e87506fSArnaldo Carvalho de Melo * don't need to grab this lock in read mode too as rskq_accept_head. writes 1790e87506fSArnaldo Carvalho de Melo * are always protected from the main sock lock. 1800e87506fSArnaldo Carvalho de Melo */ 1810e87506fSArnaldo Carvalho de Melo struct request_sock_queue { 1820e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_head; 1830e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_tail; 1840e87506fSArnaldo Carvalho de Melo rwlock_t syn_wait_lock; 185ec0a1966SDavid S. Miller u8 rskq_defer_accept; 186ec0a1966SDavid S. Miller /* 3 bytes hole, try to pack */ 1872ad69c55SArnaldo Carvalho de Melo struct listen_sock *listen_opt; 18810467163SJerry Chu struct fastopen_queue *fastopenq; /* This is non-NULL iff TFO has been 18910467163SJerry Chu * enabled on this listener. Check 19010467163SJerry Chu * max_qlen != 0 in fastopen_queue 19110467163SJerry Chu * to determine if TFO is enabled 19210467163SJerry Chu * right at this moment. 19310467163SJerry Chu */ 1940e87506fSArnaldo Carvalho de Melo }; 1950e87506fSArnaldo Carvalho de Melo 196c0f4502aSJoe Perches int reqsk_queue_alloc(struct request_sock_queue *queue, 19772a3effaSEric Dumazet unsigned int nr_table_entries); 1980e87506fSArnaldo Carvalho de Melo 199c0f4502aSJoe Perches void __reqsk_queue_destroy(struct request_sock_queue *queue); 200c0f4502aSJoe Perches void reqsk_queue_destroy(struct request_sock_queue *queue); 201c0f4502aSJoe Perches void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req, 202c0f4502aSJoe Perches bool reset); 20383e3609eSArnaldo Carvalho de Melo 2040e87506fSArnaldo Carvalho de Melo static inline struct request_sock * 2050e87506fSArnaldo Carvalho de Melo reqsk_queue_yank_acceptq(struct request_sock_queue *queue) 2060e87506fSArnaldo Carvalho de Melo { 2070e87506fSArnaldo Carvalho de Melo struct request_sock *req = queue->rskq_accept_head; 2080e87506fSArnaldo Carvalho de Melo 2093eb4801dSNorbert Kiesel queue->rskq_accept_head = NULL; 2100e87506fSArnaldo Carvalho de Melo return req; 2110e87506fSArnaldo Carvalho de Melo } 2120e87506fSArnaldo Carvalho de Melo 2130e87506fSArnaldo Carvalho de Melo static inline int reqsk_queue_empty(struct request_sock_queue *queue) 2140e87506fSArnaldo Carvalho de Melo { 2150e87506fSArnaldo Carvalho de Melo return queue->rskq_accept_head == NULL; 2160e87506fSArnaldo Carvalho de Melo } 2170e87506fSArnaldo Carvalho de Melo 2180e87506fSArnaldo Carvalho de Melo static inline void reqsk_queue_unlink(struct request_sock_queue *queue, 2190e87506fSArnaldo Carvalho de Melo struct request_sock *req, 2200e87506fSArnaldo Carvalho de Melo struct request_sock **prev_req) 2210e87506fSArnaldo Carvalho de Melo { 2220e87506fSArnaldo Carvalho de Melo write_lock(&queue->syn_wait_lock); 2230e87506fSArnaldo Carvalho de Melo *prev_req = req->dl_next; 2240e87506fSArnaldo Carvalho de Melo write_unlock(&queue->syn_wait_lock); 2250e87506fSArnaldo Carvalho de Melo } 2260e87506fSArnaldo Carvalho de Melo 2270e87506fSArnaldo Carvalho de Melo static inline void reqsk_queue_add(struct request_sock_queue *queue, 2280e87506fSArnaldo Carvalho de Melo struct request_sock *req, 2290e87506fSArnaldo Carvalho de Melo struct sock *parent, 2300e87506fSArnaldo Carvalho de Melo struct sock *child) 2310e87506fSArnaldo Carvalho de Melo { 2320e87506fSArnaldo Carvalho de Melo req->sk = child; 2330e87506fSArnaldo Carvalho de Melo sk_acceptq_added(parent); 2340e87506fSArnaldo Carvalho de Melo 2350e87506fSArnaldo Carvalho de Melo if (queue->rskq_accept_head == NULL) 2360e87506fSArnaldo Carvalho de Melo queue->rskq_accept_head = req; 2370e87506fSArnaldo Carvalho de Melo else 2380e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail->dl_next = req; 2390e87506fSArnaldo Carvalho de Melo 2400e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail = req; 2410e87506fSArnaldo Carvalho de Melo req->dl_next = NULL; 2420e87506fSArnaldo Carvalho de Melo } 2430e87506fSArnaldo Carvalho de Melo 2440e87506fSArnaldo Carvalho de Melo static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue) 2450e87506fSArnaldo Carvalho de Melo { 2460e87506fSArnaldo Carvalho de Melo struct request_sock *req = queue->rskq_accept_head; 2470e87506fSArnaldo Carvalho de Melo 248547b792cSIlpo Järvinen WARN_ON(req == NULL); 2490e87506fSArnaldo Carvalho de Melo 2500e87506fSArnaldo Carvalho de Melo queue->rskq_accept_head = req->dl_next; 2510e87506fSArnaldo Carvalho de Melo if (queue->rskq_accept_head == NULL) 2520e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail = NULL; 2530e87506fSArnaldo Carvalho de Melo 2540e87506fSArnaldo Carvalho de Melo return req; 2550e87506fSArnaldo Carvalho de Melo } 2560e87506fSArnaldo Carvalho de Melo 2570e87506fSArnaldo Carvalho de Melo static inline int reqsk_queue_removed(struct request_sock_queue *queue, 2580e87506fSArnaldo Carvalho de Melo struct request_sock *req) 2590e87506fSArnaldo Carvalho de Melo { 2602ad69c55SArnaldo Carvalho de Melo struct listen_sock *lopt = queue->listen_opt; 2610e87506fSArnaldo Carvalho de Melo 262e6c022a4SEric Dumazet if (req->num_timeout == 0) 2630e87506fSArnaldo Carvalho de Melo --lopt->qlen_young; 2640e87506fSArnaldo Carvalho de Melo 2650e87506fSArnaldo Carvalho de Melo return --lopt->qlen; 2660e87506fSArnaldo Carvalho de Melo } 2670e87506fSArnaldo Carvalho de Melo 2680e87506fSArnaldo Carvalho de Melo static inline int reqsk_queue_added(struct request_sock_queue *queue) 2690e87506fSArnaldo Carvalho de Melo { 2702ad69c55SArnaldo Carvalho de Melo struct listen_sock *lopt = queue->listen_opt; 2710e87506fSArnaldo Carvalho de Melo const int prev_qlen = lopt->qlen; 2720e87506fSArnaldo Carvalho de Melo 2730e87506fSArnaldo Carvalho de Melo lopt->qlen_young++; 2740e87506fSArnaldo Carvalho de Melo lopt->qlen++; 2750e87506fSArnaldo Carvalho de Melo return prev_qlen; 2760e87506fSArnaldo Carvalho de Melo } 2770e87506fSArnaldo Carvalho de Melo 278463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len(const struct request_sock_queue *queue) 2790e87506fSArnaldo Carvalho de Melo { 2800e87506fSArnaldo Carvalho de Melo return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0; 2810e87506fSArnaldo Carvalho de Melo } 2820e87506fSArnaldo Carvalho de Melo 283463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len_young(const struct request_sock_queue *queue) 2840e87506fSArnaldo Carvalho de Melo { 2850e87506fSArnaldo Carvalho de Melo return queue->listen_opt->qlen_young; 2860e87506fSArnaldo Carvalho de Melo } 2870e87506fSArnaldo Carvalho de Melo 288463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_is_full(const struct request_sock_queue *queue) 2890e87506fSArnaldo Carvalho de Melo { 2900e87506fSArnaldo Carvalho de Melo return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log; 2910e87506fSArnaldo Carvalho de Melo } 2920e87506fSArnaldo Carvalho de Melo 2930e87506fSArnaldo Carvalho de Melo static inline void reqsk_queue_hash_req(struct request_sock_queue *queue, 2940e87506fSArnaldo Carvalho de Melo u32 hash, struct request_sock *req, 2958129765aSArnaldo Carvalho de Melo unsigned long timeout) 2960e87506fSArnaldo Carvalho de Melo { 2972ad69c55SArnaldo Carvalho de Melo struct listen_sock *lopt = queue->listen_opt; 2980e87506fSArnaldo Carvalho de Melo 2990e87506fSArnaldo Carvalho de Melo req->expires = jiffies + timeout; 300e6c022a4SEric Dumazet req->num_retrans = 0; 301e6c022a4SEric Dumazet req->num_timeout = 0; 3020e87506fSArnaldo Carvalho de Melo req->sk = NULL; 3030e87506fSArnaldo Carvalho de Melo req->dl_next = lopt->syn_table[hash]; 3040e87506fSArnaldo Carvalho de Melo 3050470c8caSEric Dumazet /* before letting lookups find us, make sure all req fields 3060470c8caSEric Dumazet * are committed to memory and refcnt initialized. 3070470c8caSEric Dumazet */ 3080470c8caSEric Dumazet smp_wmb(); 3090470c8caSEric Dumazet atomic_set(&req->rsk_refcnt, 1); 3100470c8caSEric Dumazet 3110e87506fSArnaldo Carvalho de Melo write_lock(&queue->syn_wait_lock); 3120e87506fSArnaldo Carvalho de Melo lopt->syn_table[hash] = req; 3130e87506fSArnaldo Carvalho de Melo write_unlock(&queue->syn_wait_lock); 3140e87506fSArnaldo Carvalho de Melo } 3150e87506fSArnaldo Carvalho de Melo 3162e6599cbSArnaldo Carvalho de Melo #endif /* _REQUEST_SOCK_H */ 317