diff options
Diffstat (limited to 'kernel/include/net/request_sock.h')
| -rw-r--r-- | kernel/include/net/request_sock.h | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/kernel/include/net/request_sock.h b/kernel/include/net/request_sock.h new file mode 100644 index 000000000..9f4265ce8 --- /dev/null +++ b/kernel/include/net/request_sock.h @@ -0,0 +1,294 @@ +/* + * NET Generic infrastructure for Network protocols. + * + * Definitions for request_sock + * + * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br> + * + * From code originally in include/net/tcp.h + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ +#ifndef _REQUEST_SOCK_H +#define _REQUEST_SOCK_H + +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/types.h> +#include <linux/bug.h> + +#include <net/sock.h> + +struct request_sock; +struct sk_buff; +struct dst_entry; +struct proto; + +struct request_sock_ops { + int family; + int obj_size; + struct kmem_cache *slab; + char *slab_name; + int (*rtx_syn_ack)(struct sock *sk, + struct request_sock *req); + void (*send_ack)(struct sock *sk, struct sk_buff *skb, + struct request_sock *req); + void (*send_reset)(struct sock *sk, + struct sk_buff *skb); + void (*destructor)(struct request_sock *req); + void (*syn_ack_timeout)(const struct request_sock *req); +}; + +int inet_rtx_syn_ack(struct sock *parent, struct request_sock *req); + +/* struct request_sock - mini sock to represent a connection request + */ +struct request_sock { + struct sock_common __req_common; +#define rsk_refcnt __req_common.skc_refcnt +#define rsk_hash __req_common.skc_hash + + struct request_sock *dl_next; + struct sock *rsk_listener; + u16 mss; + u8 num_retrans; /* number of retransmits */ + u8 cookie_ts:1; /* syncookie: encode tcpopts in timestamp */ + u8 num_timeout:7; /* number of timeouts */ + /* The following two fields can be easily recomputed I think -AK */ + u32 window_clamp; /* window clamp at creation time */ + u32 rcv_wnd; /* rcv_wnd offered first time */ + u32 ts_recent; + struct timer_list rsk_timer; + const struct request_sock_ops *rsk_ops; + struct sock *sk; + u32 secid; + u32 peer_secid; +}; + +static inline struct request_sock * +reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener) +{ + struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC); + + if (req) { + req->rsk_ops = ops; + sock_hold(sk_listener); + req->rsk_listener = sk_listener; + + /* Following is temporary. It is coupled with debugging + * helpers in reqsk_put() & reqsk_free() + */ + atomic_set(&req->rsk_refcnt, 0); + } + return req; +} + +static inline struct request_sock *inet_reqsk(struct sock *sk) +{ + return (struct request_sock *)sk; +} + +static inline struct sock *req_to_sk(struct request_sock *req) +{ + return (struct sock *)req; +} + +static inline void reqsk_free(struct request_sock *req) +{ + /* temporary debugging */ + WARN_ON_ONCE(atomic_read(&req->rsk_refcnt) != 0); + + req->rsk_ops->destructor(req); + if (req->rsk_listener) + sock_put(req->rsk_listener); + kmem_cache_free(req->rsk_ops->slab, req); +} + +static inline void reqsk_put(struct request_sock *req) +{ + if (atomic_dec_and_test(&req->rsk_refcnt)) + reqsk_free(req); +} + +extern int sysctl_max_syn_backlog; + +/** struct listen_sock - listen state + * + * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs + */ +struct listen_sock { + int qlen_inc; /* protected by listener lock */ + int young_inc;/* protected by listener lock */ + + /* following fields can be updated by timer */ + atomic_t qlen_dec; /* qlen = qlen_inc - qlen_dec */ + atomic_t young_dec; + + u8 max_qlen_log ____cacheline_aligned_in_smp; + u8 synflood_warned; + /* 2 bytes hole, try to use */ + u32 hash_rnd; + u32 nr_table_entries; + struct request_sock *syn_table[0]; +}; + +/* + * For a TCP Fast Open listener - + * lock - protects the access to all the reqsk, which is co-owned by + * the listener and the child socket. + * qlen - pending TFO requests (still in TCP_SYN_RECV). + * max_qlen - max TFO reqs allowed before TFO is disabled. + * + * XXX (TFO) - ideally these fields can be made as part of "listen_sock" + * structure above. But there is some implementation difficulty due to + * listen_sock being part of request_sock_queue hence will be freed when + * a listener is stopped. But TFO related fields may continue to be + * accessed even after a listener is closed, until its sk_refcnt drops + * to 0 implying no more outstanding TFO reqs. One solution is to keep + * listen_opt around until sk_refcnt drops to 0. But there is some other + * complexity that needs to be resolved. E.g., a listener can be disabled + * temporarily through shutdown()->tcp_disconnect(), and re-enabled later. + */ +struct fastopen_queue { + struct request_sock *rskq_rst_head; /* Keep track of past TFO */ + struct request_sock *rskq_rst_tail; /* requests that caused RST. + * This is part of the defense + * against spoofing attack. + */ + spinlock_t lock; + int qlen; /* # of pending (TCP_SYN_RECV) reqs */ + int max_qlen; /* != 0 iff TFO is currently enabled */ +}; + +/** struct request_sock_queue - queue of request_socks + * + * @rskq_accept_head - FIFO head of established children + * @rskq_accept_tail - FIFO tail of established children + * @rskq_defer_accept - User waits for some data after accept() + * @syn_wait_lock - serializer + * + * %syn_wait_lock is necessary only to avoid proc interface having to grab the main + * lock sock while browsing the listening hash (otherwise it's deadlock prone). + * + */ +struct request_sock_queue { + struct request_sock *rskq_accept_head; + struct request_sock *rskq_accept_tail; + u8 rskq_defer_accept; + struct listen_sock *listen_opt; + struct fastopen_queue *fastopenq; /* This is non-NULL iff TFO has been + * enabled on this listener. Check + * max_qlen != 0 in fastopen_queue + * to determine if TFO is enabled + * right at this moment. + */ + + /* temporary alignment, our goal is to get rid of this lock */ + spinlock_t syn_wait_lock ____cacheline_aligned_in_smp; +}; + +int reqsk_queue_alloc(struct request_sock_queue *queue, + unsigned int nr_table_entries); + +void __reqsk_queue_destroy(struct request_sock_queue *queue); +void reqsk_queue_destroy(struct request_sock_queue *queue); +void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req, + bool reset); + +static inline struct request_sock * + reqsk_queue_yank_acceptq(struct request_sock_queue *queue) +{ + struct request_sock *req = queue->rskq_accept_head; + + queue->rskq_accept_head = NULL; + return req; +} + +static inline int reqsk_queue_empty(struct request_sock_queue *queue) +{ + return queue->rskq_accept_head == NULL; +} + +static inline void reqsk_queue_add(struct request_sock_queue *queue, + struct request_sock *req, + struct sock *parent, + struct sock *child) +{ + req->sk = child; + sk_acceptq_added(parent); + + if (queue->rskq_accept_head == NULL) + queue->rskq_accept_head = req; + else + queue->rskq_accept_tail->dl_next = req; + + queue->rskq_accept_tail = req; + req->dl_next = NULL; +} + +static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue) +{ + struct request_sock *req = queue->rskq_accept_head; + + WARN_ON(req == NULL); + + queue->rskq_accept_head = req->dl_next; + if (queue->rskq_accept_head == NULL) + queue->rskq_accept_tail = NULL; + + return req; +} + +static inline void reqsk_queue_removed(struct request_sock_queue *queue, + const struct request_sock *req) +{ + struct listen_sock *lopt = queue->listen_opt; + + if (req->num_timeout == 0) + atomic_inc(&lopt->young_dec); + atomic_inc(&lopt->qlen_dec); +} + +static inline void reqsk_queue_added(struct request_sock_queue *queue) +{ + struct listen_sock *lopt = queue->listen_opt; + + lopt->young_inc++; + lopt->qlen_inc++; +} + +static inline int listen_sock_qlen(const struct listen_sock *lopt) +{ + return lopt->qlen_inc - atomic_read(&lopt->qlen_dec); +} + +static inline int listen_sock_young(const struct listen_sock *lopt) +{ + return lopt->young_inc - atomic_read(&lopt->young_dec); +} + +static inline int reqsk_queue_len(const struct request_sock_queue *queue) +{ + const struct listen_sock *lopt = queue->listen_opt; + + return lopt ? listen_sock_qlen(lopt) : 0; +} + +static inline int reqsk_queue_len_young(const struct request_sock_queue *queue) +{ + return listen_sock_young(queue->listen_opt); +} + +static inline int reqsk_queue_is_full(const struct request_sock_queue *queue) +{ + return reqsk_queue_len(queue) >> queue->listen_opt->max_qlen_log; +} + +void reqsk_queue_hash_req(struct request_sock_queue *queue, + u32 hash, struct request_sock *req, + unsigned long timeout); + +#endif /* _REQUEST_SOCK_H */ |