linux/net/handshake/request.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Handshake request lifetime events
 *
 * Author: Chuck Lever <[email protected]>
 *
 * Copyright (c) 2023, Oracle and/or its affiliates.
 */

#include <linux/types.h>
#include <linux/socket.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/inet.h>
#include <linux/fdtable.h>
#include <linux/rhashtable.h>

#include <net/sock.h>
#include <net/genetlink.h>
#include <net/netns/generic.h>

#include <kunit/visibility.h>

#include <uapi/linux/handshake.h>
#include "handshake.h"

#include <trace/events/handshake.h>

/*
 * We need both a handshake_req -> sock mapping, and a sock ->
 * handshake_req mapping. Both are one-to-one.
 *
 * To avoid adding another pointer field to struct sock, net/handshake
 * maintains a hash table, indexed by the memory address of @sock, to
 * find the struct handshake_req outstanding for that socket. The
 * reverse direction uses a simple pointer field in the handshake_req
 * struct.
 */

static struct rhashtable handshake_rhashtbl ____cacheline_aligned_in_smp;

static const struct rhashtable_params handshake_rhash_params = …;

int handshake_req_hash_init(void)
{ … }

void handshake_req_hash_destroy(void)
{ … }

struct handshake_req *handshake_req_hash_lookup(struct sock *sk)
{ … }
EXPORT_SYMBOL_IF_KUNIT(…);

static bool handshake_req_hash_add(struct handshake_req *req)
{ … }

static void handshake_req_destroy(struct handshake_req *req)
{ … }

static void handshake_sk_destruct(struct sock *sk)
{ … }

/**
 * handshake_req_alloc - Allocate a handshake request
 * @proto: security protocol
 * @flags: memory allocation flags
 *
 * Returns an initialized handshake_req or NULL.
 */
struct handshake_req *handshake_req_alloc(const struct handshake_proto *proto,
					  gfp_t flags)
{ … }
EXPORT_SYMBOL(…);

/**
 * handshake_req_private - Get per-handshake private data
 * @req: handshake arguments
 *
 */
void *handshake_req_private(struct handshake_req *req)
{ … }
EXPORT_SYMBOL(…);

static bool __add_pending_locked(struct handshake_net *hn,
				 struct handshake_req *req)
{ … }

static void __remove_pending_locked(struct handshake_net *hn,
				    struct handshake_req *req)
{ … }

/*
 * Returns %true if the request was found on @net's pending list,
 * otherwise %false.
 *
 * If @req was on a pending list, it has not yet been accepted.
 */
static bool remove_pending(struct handshake_net *hn, struct handshake_req *req)
{ … }

struct handshake_req *handshake_req_next(struct handshake_net *hn, int class)
{ … }
EXPORT_SYMBOL_IF_KUNIT(…);

/**
 * handshake_req_submit - Submit a handshake request
 * @sock: open socket on which to perform the handshake
 * @req: handshake arguments
 * @flags: memory allocation flags
 *
 * Return values:
 *   %0: Request queued
 *   %-EINVAL: Invalid argument
 *   %-EBUSY: A handshake is already under way for this socket
 *   %-ESRCH: No handshake agent is available
 *   %-EAGAIN: Too many pending handshake requests
 *   %-ENOMEM: Failed to allocate memory
 *   %-EMSGSIZE: Failed to construct notification message
 *   %-EOPNOTSUPP: Handshake module not initialized
 *
 * A zero return value from handshake_req_submit() means that
 * exactly one subsequent completion callback is guaranteed.
 *
 * A negative return value from handshake_req_submit() means that
 * no completion callback will be done and that @req has been
 * destroyed.
 */
int handshake_req_submit(struct socket *sock, struct handshake_req *req,
			 gfp_t flags)
{ … }
EXPORT_SYMBOL(…);

void handshake_complete(struct handshake_req *req, unsigned int status,
			struct genl_info *info)
{ … }
EXPORT_SYMBOL_IF_KUNIT(…);

/**
 * handshake_req_cancel - Cancel an in-progress handshake
 * @sk: socket on which there is an ongoing handshake
 *
 * Request cancellation races with request completion. To determine
 * who won, callers examine the return value from this function.
 *
 * Return values:
 *   %true - Uncompleted handshake request was canceled
 *   %false - Handshake request already completed or not found
 */
bool handshake_req_cancel(struct sock *sk)
{ … }
EXPORT_SYMBOL(…);