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 { 513fb62c5dSEric Dumazet struct request_sock *dl_next; 522e6599cbSArnaldo Carvalho de Melo u16 mss; 53e6c022a4SEric Dumazet u8 num_retrans; /* number of retransmits */ 54e6c022a4SEric Dumazet u8 cookie_ts:1; /* syncookie: encode tcpopts in timestamp */ 55e6c022a4SEric Dumazet u8 num_timeout:7; /* number of timeouts */ 562e6599cbSArnaldo Carvalho de Melo /* The following two fields can be easily recomputed I think -AK */ 572e6599cbSArnaldo Carvalho de Melo u32 window_clamp; /* window clamp at creation time */ 582e6599cbSArnaldo Carvalho de Melo u32 rcv_wnd; /* rcv_wnd offered first time */ 592e6599cbSArnaldo Carvalho de Melo u32 ts_recent; 602e6599cbSArnaldo Carvalho de Melo unsigned long expires; 6172a3effaSEric Dumazet const struct request_sock_ops *rsk_ops; 622e6599cbSArnaldo Carvalho de Melo struct sock *sk; 634237c75cSVenkat Yekkirala u32 secid; 646b877699SVenkat Yekkirala u32 peer_secid; 652e6599cbSArnaldo Carvalho de Melo }; 662e6599cbSArnaldo Carvalho de Melo 6772a3effaSEric Dumazet static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops) 682e6599cbSArnaldo Carvalho de Melo { 6954e6ecb2SChristoph Lameter struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC); 702e6599cbSArnaldo Carvalho de Melo 712e6599cbSArnaldo Carvalho de Melo if (req != NULL) 7260236fddSArnaldo Carvalho de Melo req->rsk_ops = ops; 732e6599cbSArnaldo Carvalho de Melo 742e6599cbSArnaldo Carvalho de Melo return req; 752e6599cbSArnaldo Carvalho de Melo } 762e6599cbSArnaldo Carvalho de Melo 7760236fddSArnaldo Carvalho de Melo static inline void __reqsk_free(struct request_sock *req) 782e6599cbSArnaldo Carvalho de Melo { 7960236fddSArnaldo Carvalho de Melo kmem_cache_free(req->rsk_ops->slab, req); 802e6599cbSArnaldo Carvalho de Melo } 812e6599cbSArnaldo Carvalho de Melo 8260236fddSArnaldo Carvalho de Melo static inline void reqsk_free(struct request_sock *req) 832e6599cbSArnaldo Carvalho de Melo { 8460236fddSArnaldo Carvalho de Melo req->rsk_ops->destructor(req); 8560236fddSArnaldo Carvalho de Melo __reqsk_free(req); 862e6599cbSArnaldo Carvalho de Melo } 872e6599cbSArnaldo Carvalho de Melo 880e87506fSArnaldo Carvalho de Melo extern int sysctl_max_syn_backlog; 890e87506fSArnaldo Carvalho de Melo 902ad69c55SArnaldo Carvalho de Melo /** struct listen_sock - listen state 910e87506fSArnaldo Carvalho de Melo * 920e87506fSArnaldo Carvalho de Melo * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs 930e87506fSArnaldo Carvalho de Melo */ 942ad69c55SArnaldo Carvalho de Melo struct listen_sock { 950e87506fSArnaldo Carvalho de Melo u8 max_qlen_log; 96946cedccSEric Dumazet u8 synflood_warned; 97946cedccSEric Dumazet /* 2 bytes hole, try to use */ 980e87506fSArnaldo Carvalho de Melo int qlen; 990e87506fSArnaldo Carvalho de Melo int qlen_young; 1000e87506fSArnaldo Carvalho de Melo int clock_hand; 1010e87506fSArnaldo Carvalho de Melo u32 hash_rnd; 10283e3609eSArnaldo Carvalho de Melo u32 nr_table_entries; 1030e87506fSArnaldo Carvalho de Melo struct request_sock *syn_table[0]; 1040e87506fSArnaldo Carvalho de Melo }; 1050e87506fSArnaldo Carvalho de Melo 10610467163SJerry Chu /* 10710467163SJerry Chu * For a TCP Fast Open listener - 10810467163SJerry Chu * lock - protects the access to all the reqsk, which is co-owned by 10910467163SJerry Chu * the listener and the child socket. 11010467163SJerry Chu * qlen - pending TFO requests (still in TCP_SYN_RECV). 11110467163SJerry Chu * max_qlen - max TFO reqs allowed before TFO is disabled. 11210467163SJerry Chu * 11310467163SJerry Chu * XXX (TFO) - ideally these fields can be made as part of "listen_sock" 11410467163SJerry Chu * structure above. But there is some implementation difficulty due to 11510467163SJerry Chu * listen_sock being part of request_sock_queue hence will be freed when 11610467163SJerry Chu * a listener is stopped. But TFO related fields may continue to be 11710467163SJerry Chu * accessed even after a listener is closed, until its sk_refcnt drops 11810467163SJerry Chu * to 0 implying no more outstanding TFO reqs. One solution is to keep 11910467163SJerry Chu * listen_opt around until sk_refcnt drops to 0. But there is some other 12010467163SJerry Chu * complexity that needs to be resolved. E.g., a listener can be disabled 12110467163SJerry Chu * temporarily through shutdown()->tcp_disconnect(), and re-enabled later. 12210467163SJerry Chu */ 12310467163SJerry Chu struct fastopen_queue { 12410467163SJerry Chu struct request_sock *rskq_rst_head; /* Keep track of past TFO */ 12510467163SJerry Chu struct request_sock *rskq_rst_tail; /* requests that caused RST. 12610467163SJerry Chu * This is part of the defense 12710467163SJerry Chu * against spoofing attack. 12810467163SJerry Chu */ 12910467163SJerry Chu spinlock_t lock; 13010467163SJerry Chu int qlen; /* # of pending (TCP_SYN_RECV) reqs */ 13110467163SJerry Chu int max_qlen; /* != 0 iff TFO is currently enabled */ 13210467163SJerry Chu }; 13310467163SJerry Chu 1340e87506fSArnaldo Carvalho de Melo /** struct request_sock_queue - queue of request_socks 1350e87506fSArnaldo Carvalho de Melo * 1360e87506fSArnaldo Carvalho de Melo * @rskq_accept_head - FIFO head of established children 1370e87506fSArnaldo Carvalho de Melo * @rskq_accept_tail - FIFO tail of established children 138295f7324SArnaldo Carvalho de Melo * @rskq_defer_accept - User waits for some data after accept() 1390e87506fSArnaldo Carvalho de Melo * @syn_wait_lock - serializer 1400e87506fSArnaldo Carvalho de Melo * 1410e87506fSArnaldo Carvalho de Melo * %syn_wait_lock is necessary only to avoid proc interface having to grab the main 1420e87506fSArnaldo Carvalho de Melo * lock sock while browsing the listening hash (otherwise it's deadlock prone). 1430e87506fSArnaldo Carvalho de Melo * 1440e87506fSArnaldo Carvalho de Melo * This lock is acquired in read mode only from listening_get_next() seq_file 1450e87506fSArnaldo Carvalho de Melo * op and it's acquired in write mode _only_ from code that is actively 1460e87506fSArnaldo Carvalho de Melo * changing rskq_accept_head. All readers that are holding the master sock lock 1470e87506fSArnaldo Carvalho de Melo * don't need to grab this lock in read mode too as rskq_accept_head. writes 1480e87506fSArnaldo Carvalho de Melo * are always protected from the main sock lock. 1490e87506fSArnaldo Carvalho de Melo */ 1500e87506fSArnaldo Carvalho de Melo struct request_sock_queue { 1510e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_head; 1520e87506fSArnaldo Carvalho de Melo struct request_sock *rskq_accept_tail; 1530e87506fSArnaldo Carvalho de Melo rwlock_t syn_wait_lock; 154ec0a1966SDavid S. Miller u8 rskq_defer_accept; 155ec0a1966SDavid S. Miller /* 3 bytes hole, try to pack */ 1562ad69c55SArnaldo Carvalho de Melo struct listen_sock *listen_opt; 15710467163SJerry Chu struct fastopen_queue *fastopenq; /* This is non-NULL iff TFO has been 15810467163SJerry Chu * enabled on this listener. Check 15910467163SJerry Chu * max_qlen != 0 in fastopen_queue 16010467163SJerry Chu * to determine if TFO is enabled 16110467163SJerry Chu * right at this moment. 16210467163SJerry Chu */ 1630e87506fSArnaldo Carvalho de Melo }; 1640e87506fSArnaldo Carvalho de Melo 165c0f4502aSJoe Perches int reqsk_queue_alloc(struct request_sock_queue *queue, 16672a3effaSEric Dumazet unsigned int nr_table_entries); 1670e87506fSArnaldo Carvalho de Melo 168c0f4502aSJoe Perches void __reqsk_queue_destroy(struct request_sock_queue *queue); 169c0f4502aSJoe Perches void reqsk_queue_destroy(struct request_sock_queue *queue); 170c0f4502aSJoe Perches void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req, 171c0f4502aSJoe Perches bool reset); 17283e3609eSArnaldo Carvalho de Melo 1730e87506fSArnaldo Carvalho de Melo static inline struct request_sock * 1740e87506fSArnaldo Carvalho de Melo reqsk_queue_yank_acceptq(struct request_sock_queue *queue) 1750e87506fSArnaldo Carvalho de Melo { 1760e87506fSArnaldo Carvalho de Melo struct request_sock *req = queue->rskq_accept_head; 1770e87506fSArnaldo Carvalho de Melo 1783eb4801dSNorbert Kiesel queue->rskq_accept_head = NULL; 1790e87506fSArnaldo Carvalho de Melo return req; 1800e87506fSArnaldo Carvalho de Melo } 1810e87506fSArnaldo Carvalho de Melo 1820e87506fSArnaldo Carvalho de Melo static inline int reqsk_queue_empty(struct request_sock_queue *queue) 1830e87506fSArnaldo Carvalho de Melo { 1840e87506fSArnaldo Carvalho de Melo return queue->rskq_accept_head == NULL; 1850e87506fSArnaldo Carvalho de Melo } 1860e87506fSArnaldo Carvalho de Melo 1870e87506fSArnaldo Carvalho de Melo static inline void reqsk_queue_unlink(struct request_sock_queue *queue, 1880e87506fSArnaldo Carvalho de Melo struct request_sock *req, 1890e87506fSArnaldo Carvalho de Melo struct request_sock **prev_req) 1900e87506fSArnaldo Carvalho de Melo { 1910e87506fSArnaldo Carvalho de Melo write_lock(&queue->syn_wait_lock); 1920e87506fSArnaldo Carvalho de Melo *prev_req = req->dl_next; 1930e87506fSArnaldo Carvalho de Melo write_unlock(&queue->syn_wait_lock); 1940e87506fSArnaldo Carvalho de Melo } 1950e87506fSArnaldo Carvalho de Melo 1960e87506fSArnaldo Carvalho de Melo static inline void reqsk_queue_add(struct request_sock_queue *queue, 1970e87506fSArnaldo Carvalho de Melo struct request_sock *req, 1980e87506fSArnaldo Carvalho de Melo struct sock *parent, 1990e87506fSArnaldo Carvalho de Melo struct sock *child) 2000e87506fSArnaldo Carvalho de Melo { 2010e87506fSArnaldo Carvalho de Melo req->sk = child; 2020e87506fSArnaldo Carvalho de Melo sk_acceptq_added(parent); 2030e87506fSArnaldo Carvalho de Melo 2040e87506fSArnaldo Carvalho de Melo if (queue->rskq_accept_head == NULL) 2050e87506fSArnaldo Carvalho de Melo queue->rskq_accept_head = req; 2060e87506fSArnaldo Carvalho de Melo else 2070e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail->dl_next = req; 2080e87506fSArnaldo Carvalho de Melo 2090e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail = req; 2100e87506fSArnaldo Carvalho de Melo req->dl_next = NULL; 2110e87506fSArnaldo Carvalho de Melo } 2120e87506fSArnaldo Carvalho de Melo 2130e87506fSArnaldo Carvalho de Melo static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue) 2140e87506fSArnaldo Carvalho de Melo { 2150e87506fSArnaldo Carvalho de Melo struct request_sock *req = queue->rskq_accept_head; 2160e87506fSArnaldo Carvalho de Melo 217547b792cSIlpo Järvinen WARN_ON(req == NULL); 2180e87506fSArnaldo Carvalho de Melo 2190e87506fSArnaldo Carvalho de Melo queue->rskq_accept_head = req->dl_next; 2200e87506fSArnaldo Carvalho de Melo if (queue->rskq_accept_head == NULL) 2210e87506fSArnaldo Carvalho de Melo queue->rskq_accept_tail = NULL; 2220e87506fSArnaldo Carvalho de Melo 2230e87506fSArnaldo Carvalho de Melo return req; 2240e87506fSArnaldo Carvalho de Melo } 2250e87506fSArnaldo Carvalho de Melo 2260e87506fSArnaldo Carvalho de Melo static inline int reqsk_queue_removed(struct request_sock_queue *queue, 2270e87506fSArnaldo Carvalho de Melo struct request_sock *req) 2280e87506fSArnaldo Carvalho de Melo { 2292ad69c55SArnaldo Carvalho de Melo struct listen_sock *lopt = queue->listen_opt; 2300e87506fSArnaldo Carvalho de Melo 231e6c022a4SEric Dumazet if (req->num_timeout == 0) 2320e87506fSArnaldo Carvalho de Melo --lopt->qlen_young; 2330e87506fSArnaldo Carvalho de Melo 2340e87506fSArnaldo Carvalho de Melo return --lopt->qlen; 2350e87506fSArnaldo Carvalho de Melo } 2360e87506fSArnaldo Carvalho de Melo 2370e87506fSArnaldo Carvalho de Melo static inline int reqsk_queue_added(struct request_sock_queue *queue) 2380e87506fSArnaldo Carvalho de Melo { 2392ad69c55SArnaldo Carvalho de Melo struct listen_sock *lopt = queue->listen_opt; 2400e87506fSArnaldo Carvalho de Melo const int prev_qlen = lopt->qlen; 2410e87506fSArnaldo Carvalho de Melo 2420e87506fSArnaldo Carvalho de Melo lopt->qlen_young++; 2430e87506fSArnaldo Carvalho de Melo lopt->qlen++; 2440e87506fSArnaldo Carvalho de Melo return prev_qlen; 2450e87506fSArnaldo Carvalho de Melo } 2460e87506fSArnaldo Carvalho de Melo 247463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len(const struct request_sock_queue *queue) 2480e87506fSArnaldo Carvalho de Melo { 2490e87506fSArnaldo Carvalho de Melo return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0; 2500e87506fSArnaldo Carvalho de Melo } 2510e87506fSArnaldo Carvalho de Melo 252463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_len_young(const struct request_sock_queue *queue) 2530e87506fSArnaldo Carvalho de Melo { 2540e87506fSArnaldo Carvalho de Melo return queue->listen_opt->qlen_young; 2550e87506fSArnaldo Carvalho de Melo } 2560e87506fSArnaldo Carvalho de Melo 257463c84b9SArnaldo Carvalho de Melo static inline int reqsk_queue_is_full(const struct request_sock_queue *queue) 2580e87506fSArnaldo Carvalho de Melo { 2590e87506fSArnaldo Carvalho de Melo return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log; 2600e87506fSArnaldo Carvalho de Melo } 2610e87506fSArnaldo Carvalho de Melo 2620e87506fSArnaldo Carvalho de Melo static inline void reqsk_queue_hash_req(struct request_sock_queue *queue, 2630e87506fSArnaldo Carvalho de Melo u32 hash, struct request_sock *req, 2648129765aSArnaldo Carvalho de Melo unsigned long timeout) 2650e87506fSArnaldo Carvalho de Melo { 2662ad69c55SArnaldo Carvalho de Melo struct listen_sock *lopt = queue->listen_opt; 2670e87506fSArnaldo Carvalho de Melo 2680e87506fSArnaldo Carvalho de Melo req->expires = jiffies + timeout; 269e6c022a4SEric Dumazet req->num_retrans = 0; 270e6c022a4SEric Dumazet req->num_timeout = 0; 2710e87506fSArnaldo Carvalho de Melo req->sk = NULL; 2720e87506fSArnaldo Carvalho de Melo req->dl_next = lopt->syn_table[hash]; 2730e87506fSArnaldo Carvalho de Melo 2740e87506fSArnaldo Carvalho de Melo write_lock(&queue->syn_wait_lock); 2750e87506fSArnaldo Carvalho de Melo lopt->syn_table[hash] = req; 2760e87506fSArnaldo Carvalho de Melo write_unlock(&queue->syn_wait_lock); 2770e87506fSArnaldo Carvalho de Melo } 2780e87506fSArnaldo Carvalho de Melo 2792e6599cbSArnaldo Carvalho de Melo #endif /* _REQUEST_SOCK_H */ 280