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; 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 /* The following two fields can be easily recomputed I think -AK */ 602e6599cbSArnaldo Carvalho de Melo u32 window_clamp; /* window clamp at creation time */ 612e6599cbSArnaldo Carvalho de Melo u32 rcv_wnd; /* rcv_wnd offered first time */ 622e6599cbSArnaldo Carvalho de Melo u32 ts_recent; 632e6599cbSArnaldo Carvalho de Melo unsigned long expires; 6472a3effaSEric Dumazet const struct request_sock_ops *rsk_ops; 652e6599cbSArnaldo Carvalho de Melo struct sock *sk; 664237c75cSVenkat Yekkirala u32 secid; 676b877699SVenkat Yekkirala u32 peer_secid; 682e6599cbSArnaldo Carvalho de Melo }; 692e6599cbSArnaldo Carvalho de Melo 7072a3effaSEric Dumazet static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops) 712e6599cbSArnaldo Carvalho de Melo { 7254e6ecb2SChristoph Lameter struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC); 732e6599cbSArnaldo Carvalho de Melo 742e6599cbSArnaldo Carvalho de Melo if (req != NULL) 7560236fddSArnaldo Carvalho de Melo req->rsk_ops = ops; 762e6599cbSArnaldo Carvalho de Melo 772e6599cbSArnaldo Carvalho de Melo return req; 782e6599cbSArnaldo Carvalho de Melo } 792e6599cbSArnaldo Carvalho de Melo 8041b822c5SEric Dumazet static inline struct request_sock *inet_reqsk(struct sock *sk) 8141b822c5SEric Dumazet { 8241b822c5SEric Dumazet return (struct request_sock *)sk; 8341b822c5SEric Dumazet } 8441b822c5SEric Dumazet 8560236fddSArnaldo Carvalho de Melo static inline void __reqsk_free(struct request_sock *req) 862e6599cbSArnaldo Carvalho de Melo { 8760236fddSArnaldo Carvalho de Melo kmem_cache_free(req->rsk_ops->slab, req); 882e6599cbSArnaldo Carvalho de Melo } 892e6599cbSArnaldo Carvalho de Melo 9060236fddSArnaldo Carvalho de Melo static inline void reqsk_free(struct request_sock *req) 912e6599cbSArnaldo Carvalho de Melo { 9260236fddSArnaldo Carvalho de Melo req->rsk_ops->destructor(req); 9360236fddSArnaldo Carvalho de Melo __reqsk_free(req); 942e6599cbSArnaldo Carvalho de Melo } 952e6599cbSArnaldo Carvalho de Melo 961e2e0117SEric Dumazet static inline void reqsk_put(struct request_sock *req) 971e2e0117SEric Dumazet { 981e2e0117SEric Dumazet if (atomic_dec_and_test(&req->rsk_refcnt)) 991e2e0117SEric Dumazet reqsk_free(req); 1001e2e0117SEric Dumazet } 1011e2e0117SEric Dumazet 1020e87506fSArnaldo Carvalho de Melo extern int sysctl_max_syn_backlog; 1030e87506fSArnaldo Carvalho de Melo 1042ad69c55SArnaldo Carvalho de Melo /** struct listen_sock - listen state 1050e87506fSArnaldo Carvalho de Melo * 1060e87506fSArnaldo Carvalho de Melo * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs 1070e87506fSArnaldo Carvalho de Melo */ 1082ad69c55SArnaldo Carvalho de Melo struct listen_sock { 1090e87506fSArnaldo Carvalho de Melo u8 max_qlen_log; 110946cedccSEric Dumazet u8 synflood_warned; 111946cedccSEric Dumazet /* 2 bytes hole, try to use */ 1120e87506fSArnaldo Carvalho de Melo int qlen; 1130e87506fSArnaldo Carvalho de Melo int qlen_young; 1140e87506fSArnaldo Carvalho de Melo int clock_hand; 1150e87506fSArnaldo Carvalho de Melo u32 hash_rnd; 11683e3609eSArnaldo Carvalho de Melo u32 nr_table_entries; 1170e87506fSArnaldo Carvalho de Melo struct request_sock *syn_table[0]; 1180e87506fSArnaldo Carvalho de Melo }; 1190e87506fSArnaldo Carvalho de Melo 12010467163SJerry Chu /* 12110467163SJerry Chu * For a TCP Fast Open listener - 12210467163SJerry Chu * lock - protects the access to all the reqsk, which is co-owned by 12310467163SJerry Chu * the listener and the child socket. 12410467163SJerry Chu * qlen - pending TFO requests (still in TCP_SYN_RECV). 12510467163SJerry Chu * max_qlen - max TFO reqs allowed before TFO is disabled. 12610467163SJerry Chu * 12710467163SJerry Chu * XXX (TFO) - ideally these fields can be made as part of "listen_sock" 12810467163SJerry Chu * structure above. But there is some implementation difficulty due to 12910467163SJerry Chu * listen_sock being part of request_sock_queue hence will be freed when 13010467163SJerry Chu * a listener is stopped. But TFO related fields may continue to be 13110467163SJerry Chu * accessed even after a listener is closed, until its sk_refcnt drops 13210467163SJerry Chu * to 0 implying no more outstanding TFO reqs. One solution is to keep 13310467163SJerry Chu * listen_opt around until sk_refcnt drops to 0. But there is some other 13410467163SJerry Chu * complexity that needs to be resolved. E.g., a listener can be disabled 13510467163SJerry Chu * temporarily through shutdown()->tcp_disconnect(), and re-enabled later. 13610467163SJerry Chu */ 13710467163SJerry Chu struct fastopen_queue { 13810467163SJerry Chu struct request_sock *rskq_rst_head; /* Keep track of past TFO */ 13910467163SJerry Chu struct request_sock *rskq_rst_tail; /* requests that caused RST. 14010467163SJerry Chu * This is part of the defense 14110467163SJerry Chu * against spoofing attack. 14210467163SJerry Chu */ 14310467163SJerry Chu spinlock_t lock; 14410467163SJerry Chu int qlen; /* # of pending (TCP_SYN_RECV) reqs */ 14510467163SJerry Chu int max_qlen; /* != 0 iff TFO is currently enabled */ 14610467163SJerry Chu }; 14710467163SJerry Chu 1480e87506fSArnaldo Carvalho de Melo /** struct request_sock_queue - queue of request_socks 1490e87506fSArnaldo Carvalho de Melo * 1500e87506fSArnaldo Carvalho de Melo * @rskq_accept_head - FIFO head of established children 1510e87506fSArnaldo Carvalho de Melo * @rskq_accept_tail - FIFO tail of established children 152295f7324SArnaldo Carvalho de Melo * @rskq_defer_accept - User waits for some data after accept() 1530e87506fSArnaldo Carvalho de Melo * @syn_wait_lock - serializer 1540e87506fSArnaldo Carvalho de Melo * 1550e87506fSArnaldo Carvalho de Melo * %syn_wait_lock is necessary only to avoid proc interface having to grab the main 1560e87506fSArnaldo Carvalho de Melo * lock sock while browsing the listening hash (otherwise it's deadlock prone). 1570e87506fSArnaldo Carvalho de Melo * 1580e87506fSArnaldo Carvalho de Melo * This lock is acquired in read mode only from listening_get_next() seq_file 1590e87506fSArnaldo Carvalho de Melo * op and it's acquired in write mode _only_ from code that is actively 1600e87506fSArnaldo Carvalho de Melo * changing rskq_accept_head. All readers that are holding the master sock lock 1610e87506fSArnaldo Carvalho de Melo * don't need to grab this lock in read mode too as rskq_accept_head. writes 1620e87506fSArnaldo Carvalho de Melo * are always protected from the main sock lock. 1630e87506fSArnaldo Carvalho de Melo */ 1640e87506fSArnaldo Carvalho de Melo struct request_sock_queue { 1650e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_head; 1660e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_tail; 1670e87506fSArnaldo Carvalho de Melo rwlock_t syn_wait_lock; 168ec0a1966SDavid S. Miller u8 rskq_defer_accept; 169ec0a1966SDavid S. Miller /* 3 bytes hole, try to pack */ 1702ad69c55SArnaldo Carvalho de Melo struct listen_sock *listen_opt; 17110467163SJerry Chu struct fastopen_queue *fastopenq; /* This is non-NULL iff TFO has been 17210467163SJerry Chu * enabled on this listener. Check 17310467163SJerry Chu * max_qlen != 0 in fastopen_queue 17410467163SJerry Chu * to determine if TFO is enabled 17510467163SJerry Chu * right at this moment. 17610467163SJerry Chu */ 1770e87506fSArnaldo Carvalho de Melo }; 1780e87506fSArnaldo Carvalho de Melo 179c0f4502aSJoe Perches int reqsk_queue_alloc(struct request_sock_queue *queue, 18072a3effaSEric Dumazet unsigned int nr_table_entries); 1810e87506fSArnaldo Carvalho de Melo 182c0f4502aSJoe Perches void __reqsk_queue_destroy(struct request_sock_queue *queue); 183c0f4502aSJoe Perches void reqsk_queue_destroy(struct request_sock_queue *queue); 184c0f4502aSJoe Perches void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req, 185c0f4502aSJoe Perches bool reset); 18683e3609eSArnaldo Carvalho de Melo 1870e87506fSArnaldo Carvalho de Melo static inline struct request_sock * 1880e87506fSArnaldo Carvalho de Melo reqsk_queue_yank_acceptq(struct request_sock_queue *queue) 1890e87506fSArnaldo Carvalho de Melo { 1900e87506fSArnaldo Carvalho de Melo struct request_sock *req = queue->rskq_accept_head; 1910e87506fSArnaldo Carvalho de Melo 1923eb4801dSNorbert Kiesel queue->rskq_accept_head = NULL; 1930e87506fSArnaldo Carvalho de Melo return req; 1940e87506fSArnaldo Carvalho de Melo } 1950e87506fSArnaldo Carvalho de Melo 1960e87506fSArnaldo Carvalho de Melo static inline int reqsk_queue_empty(struct request_sock_queue *queue) 1970e87506fSArnaldo Carvalho de Melo { 1980e87506fSArnaldo Carvalho de Melo return queue->rskq_accept_head == NULL; 1990e87506fSArnaldo Carvalho de Melo } 2000e87506fSArnaldo Carvalho de Melo 2010e87506fSArnaldo Carvalho de Melo static inline void reqsk_queue_unlink(struct request_sock_queue *queue, 2020e87506fSArnaldo Carvalho de Melo struct request_sock *req, 2030e87506fSArnaldo Carvalho de Melo struct request_sock **prev_req) 2040e87506fSArnaldo Carvalho de Melo { 2050e87506fSArnaldo Carvalho de Melo write_lock(&queue->syn_wait_lock); 2060e87506fSArnaldo Carvalho de Melo *prev_req = req->dl_next; 2070e87506fSArnaldo Carvalho de Melo write_unlock(&queue->syn_wait_lock); 2080e87506fSArnaldo Carvalho de Melo } 2090e87506fSArnaldo Carvalho de Melo 2100e87506fSArnaldo Carvalho de Melo static inline void reqsk_queue_add(struct request_sock_queue *queue, 2110e87506fSArnaldo Carvalho de Melo struct request_sock *req, 2120e87506fSArnaldo Carvalho de Melo struct sock *parent, 2130e87506fSArnaldo Carvalho de Melo struct sock *child) 2140e87506fSArnaldo Carvalho de Melo { 2150e87506fSArnaldo Carvalho de Melo req->sk = child; 2160e87506fSArnaldo Carvalho de Melo sk_acceptq_added(parent); 2170e87506fSArnaldo Carvalho de Melo 2180e87506fSArnaldo Carvalho de Melo if (queue->rskq_accept_head == NULL) 2190e87506fSArnaldo Carvalho de Melo queue->rskq_accept_head = req; 2200e87506fSArnaldo Carvalho de Melo else 2210e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail->dl_next = req; 2220e87506fSArnaldo Carvalho de Melo 2230e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail = req; 2240e87506fSArnaldo Carvalho de Melo req->dl_next = NULL; 2250e87506fSArnaldo Carvalho de Melo } 2260e87506fSArnaldo Carvalho de Melo 2270e87506fSArnaldo Carvalho de Melo static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue) 2280e87506fSArnaldo Carvalho de Melo { 2290e87506fSArnaldo Carvalho de Melo struct request_sock *req = queue->rskq_accept_head; 2300e87506fSArnaldo Carvalho de Melo 231547b792cSIlpo Järvinen WARN_ON(req == NULL); 2320e87506fSArnaldo Carvalho de Melo 2330e87506fSArnaldo Carvalho de Melo queue->rskq_accept_head = req->dl_next; 2340e87506fSArnaldo Carvalho de Melo if (queue->rskq_accept_head == NULL) 2350e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail = NULL; 2360e87506fSArnaldo Carvalho de Melo 2370e87506fSArnaldo Carvalho de Melo return req; 2380e87506fSArnaldo Carvalho de Melo } 2390e87506fSArnaldo Carvalho de Melo 2400e87506fSArnaldo Carvalho de Melo static inline int reqsk_queue_removed(struct request_sock_queue *queue, 2410e87506fSArnaldo Carvalho de Melo struct request_sock *req) 2420e87506fSArnaldo Carvalho de Melo { 2432ad69c55SArnaldo Carvalho de Melo struct listen_sock *lopt = queue->listen_opt; 2440e87506fSArnaldo Carvalho de Melo 245e6c022a4SEric Dumazet if (req->num_timeout == 0) 2460e87506fSArnaldo Carvalho de Melo --lopt->qlen_young; 2470e87506fSArnaldo Carvalho de Melo 2480e87506fSArnaldo Carvalho de Melo return --lopt->qlen; 2490e87506fSArnaldo Carvalho de Melo } 2500e87506fSArnaldo Carvalho de Melo 2510e87506fSArnaldo Carvalho de Melo static inline int reqsk_queue_added(struct request_sock_queue *queue) 2520e87506fSArnaldo Carvalho de Melo { 2532ad69c55SArnaldo Carvalho de Melo struct listen_sock *lopt = queue->listen_opt; 2540e87506fSArnaldo Carvalho de Melo const int prev_qlen = lopt->qlen; 2550e87506fSArnaldo Carvalho de Melo 2560e87506fSArnaldo Carvalho de Melo lopt->qlen_young++; 2570e87506fSArnaldo Carvalho de Melo lopt->qlen++; 2580e87506fSArnaldo Carvalho de Melo return prev_qlen; 2590e87506fSArnaldo Carvalho de Melo } 2600e87506fSArnaldo Carvalho de Melo 261463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len(const struct request_sock_queue *queue) 2620e87506fSArnaldo Carvalho de Melo { 2630e87506fSArnaldo Carvalho de Melo return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0; 2640e87506fSArnaldo Carvalho de Melo } 2650e87506fSArnaldo Carvalho de Melo 266463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len_young(const struct request_sock_queue *queue) 2670e87506fSArnaldo Carvalho de Melo { 2680e87506fSArnaldo Carvalho de Melo return queue->listen_opt->qlen_young; 2690e87506fSArnaldo Carvalho de Melo } 2700e87506fSArnaldo Carvalho de Melo 271463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_is_full(const struct request_sock_queue *queue) 2720e87506fSArnaldo Carvalho de Melo { 2730e87506fSArnaldo Carvalho de Melo return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log; 2740e87506fSArnaldo Carvalho de Melo } 2750e87506fSArnaldo Carvalho de Melo 2760e87506fSArnaldo Carvalho de Melo static inline void reqsk_queue_hash_req(struct request_sock_queue *queue, 2770e87506fSArnaldo Carvalho de Melo u32 hash, struct request_sock *req, 2788129765aSArnaldo Carvalho de Melo unsigned long timeout) 2790e87506fSArnaldo Carvalho de Melo { 2802ad69c55SArnaldo Carvalho de Melo struct listen_sock *lopt = queue->listen_opt; 2810e87506fSArnaldo Carvalho de Melo 2820e87506fSArnaldo Carvalho de Melo req->expires = jiffies + timeout; 283e6c022a4SEric Dumazet req->num_retrans = 0; 284e6c022a4SEric Dumazet req->num_timeout = 0; 2850e87506fSArnaldo Carvalho de Melo req->sk = NULL; 2860e87506fSArnaldo Carvalho de Melo req->dl_next = lopt->syn_table[hash]; 2870e87506fSArnaldo Carvalho de Melo 2880e87506fSArnaldo Carvalho de Melo write_lock(&queue->syn_wait_lock); 2890e87506fSArnaldo Carvalho de Melo lopt->syn_table[hash] = req; 2900e87506fSArnaldo Carvalho de Melo write_unlock(&queue->syn_wait_lock); 2910e87506fSArnaldo Carvalho de Melo } 2920e87506fSArnaldo Carvalho de Melo 2932e6599cbSArnaldo Carvalho de Melo #endif /* _REQUEST_SOCK_H */ 294