diff options
Diffstat (limited to 'include/net/request_sock.h')
| -rw-r--r-- | include/net/request_sock.h | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/include/net/request_sock.h b/include/net/request_sock.h new file mode 100644 index 000000000..144c39db9 --- /dev/null +++ b/include/net/request_sock.h @@ -0,0 +1,241 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * 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 + */ +#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 <linux/refcount.h> + +#include <net/sock.h> + +struct request_sock; +struct sk_buff; +struct dst_entry; +struct proto; + +struct request_sock_ops { + int family; + unsigned int obj_size; + struct kmem_cache *slab; + char *slab_name; + int (*rtx_syn_ack)(const struct sock *sk, + struct request_sock *req); + void (*send_ack)(const struct sock *sk, struct sk_buff *skb, + struct request_sock *req); + void (*send_reset)(const 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(const struct sock *parent, struct request_sock *req); + +struct saved_syn { + u32 mac_hdrlen; + u32 network_hdrlen; + u32 tcp_hdrlen; + u8 data[]; +}; + +/* 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 +#define rsk_listener __req_common.skc_listener +#define rsk_window_clamp __req_common.skc_window_clamp +#define rsk_rcv_wnd __req_common.skc_rcv_wnd + + struct request_sock *dl_next; + u16 mss; + u8 num_retrans; /* number of retransmits */ + u8 syncookie:1; /* syncookie: encode tcpopts in timestamp */ + u8 num_timeout:7; /* number of timeouts */ + u32 ts_recent; + struct timer_list rsk_timer; + const struct request_sock_ops *rsk_ops; + struct sock *sk; + struct saved_syn *saved_syn; + u32 secid; + u32 peer_secid; + u32 timeout; +}; + +static inline struct request_sock *inet_reqsk(const 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 struct request_sock * +reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener, + bool attach_listener) +{ + struct request_sock *req; + + req = kmem_cache_alloc(ops->slab, GFP_ATOMIC | __GFP_NOWARN); + if (!req) + return NULL; + req->rsk_listener = NULL; + if (attach_listener) { + if (unlikely(!refcount_inc_not_zero(&sk_listener->sk_refcnt))) { + kmem_cache_free(ops->slab, req); + return NULL; + } + req->rsk_listener = sk_listener; + } + req->rsk_ops = ops; + req_to_sk(req)->sk_prot = sk_listener->sk_prot; + sk_node_init(&req_to_sk(req)->sk_node); + sk_tx_queue_clear(req_to_sk(req)); + req->saved_syn = NULL; + req->timeout = 0; + req->num_timeout = 0; + req->num_retrans = 0; + req->sk = NULL; + refcount_set(&req->rsk_refcnt, 0); + + return req; +} + +static inline void __reqsk_free(struct request_sock *req) +{ + req->rsk_ops->destructor(req); + if (req->rsk_listener) + sock_put(req->rsk_listener); + kfree(req->saved_syn); + kmem_cache_free(req->rsk_ops->slab, req); +} + +static inline void reqsk_free(struct request_sock *req) +{ + WARN_ON_ONCE(refcount_read(&req->rsk_refcnt) != 0); + __reqsk_free(req); +} + +static inline void reqsk_put(struct request_sock *req) +{ + if (refcount_dec_and_test(&req->rsk_refcnt)) + reqsk_free(req); +} + +/* + * 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 tcp_fastopen_context __rcu *ctx; /* cipher context for cookie */ +}; + +/** 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() + * + */ +struct request_sock_queue { + spinlock_t rskq_lock; + u8 rskq_defer_accept; + + u32 synflood_warned; + atomic_t qlen; + atomic_t young; + + struct request_sock *rskq_accept_head; + struct request_sock *rskq_accept_tail; + struct fastopen_queue fastopenq; /* Check max_qlen != 0 to determine + * if TFO is enabled. + */ +}; + +void reqsk_queue_alloc(struct request_sock_queue *queue); + +void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req, + bool reset); + +static inline bool reqsk_queue_empty(const struct request_sock_queue *queue) +{ + return READ_ONCE(queue->rskq_accept_head) == NULL; +} + +static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue, + struct sock *parent) +{ + struct request_sock *req; + + spin_lock_bh(&queue->rskq_lock); + req = queue->rskq_accept_head; + if (req) { + sk_acceptq_removed(parent); + WRITE_ONCE(queue->rskq_accept_head, req->dl_next); + if (queue->rskq_accept_head == NULL) + queue->rskq_accept_tail = NULL; + } + spin_unlock_bh(&queue->rskq_lock); + return req; +} + +static inline void reqsk_queue_removed(struct request_sock_queue *queue, + const struct request_sock *req) +{ + if (req->num_timeout == 0) + atomic_dec(&queue->young); + atomic_dec(&queue->qlen); +} + +static inline void reqsk_queue_added(struct request_sock_queue *queue) +{ + atomic_inc(&queue->young); + atomic_inc(&queue->qlen); +} + +static inline int reqsk_queue_len(const struct request_sock_queue *queue) +{ + return atomic_read(&queue->qlen); +} + +static inline int reqsk_queue_len_young(const struct request_sock_queue *queue) +{ + return atomic_read(&queue->young); +} + +#endif /* _REQUEST_SOCK_H */ |