linux/net/sunrpc/socklib.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/net/sunrpc/socklib.c
 *
 * Common socket helper routines for RPC client and server
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <[email protected]>
 */

#include <linux/compiler.h>
#include <linux/netdevice.h>
#include <linux/gfp.h>
#include <linux/skbuff.h>
#include <linux/types.h>
#include <linux/pagemap.h>
#include <linux/udp.h>
#include <linux/sunrpc/msg_prot.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/xdr.h>
#include <linux/export.h>

#include "socklib.h"

/*
 * Helper structure for copying from an sk_buff.
 */
struct xdr_skb_reader { … };

xdr_skb_read_actor;

/**
 * xdr_skb_read_bits - copy some data bits from skb to internal buffer
 * @desc: sk_buff copy helper
 * @to: copy destination
 * @len: number of bytes to copy
 *
 * Possibly called several times to iterate over an sk_buff and copy
 * data out of it.
 */
static size_t
xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len)
{ … }

/**
 * xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
 * @desc: sk_buff copy helper
 * @to: copy destination
 * @len: number of bytes to copy
 *
 * Same as skb_read_bits, but calculate a checksum at the same time.
 */
static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to, size_t len)
{ … }

/**
 * xdr_partial_copy_from_skb - copy data out of an skb
 * @xdr: target XDR buffer
 * @base: starting offset
 * @desc: sk_buff copy helper
 * @copy_actor: virtual method for copying data
 *
 */
static ssize_t
xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct xdr_skb_reader *desc, xdr_skb_read_actor copy_actor)
{ … }

/**
 * csum_partial_copy_to_xdr - checksum and copy data
 * @xdr: target XDR buffer
 * @skb: source skb
 *
 * We have set things up such that we perform the checksum of the UDP
 * packet in parallel with the copies into the RPC client iovec.  -DaveM
 */
int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
{ … }
EXPORT_SYMBOL_GPL(…);

static inline int xprt_sendmsg(struct socket *sock, struct msghdr *msg,
			       size_t seek)
{ … }

static int xprt_send_kvec(struct socket *sock, struct msghdr *msg,
			  struct kvec *vec, size_t seek)
{ … }

static int xprt_send_pagedata(struct socket *sock, struct msghdr *msg,
			      struct xdr_buf *xdr, size_t base)
{ … }

/* Common case:
 *  - stream transport
 *  - sending from byte 0 of the message
 *  - the message is wholly contained in @xdr's head iovec
 */
static int xprt_send_rm_and_kvec(struct socket *sock, struct msghdr *msg,
				 rpc_fraghdr marker, struct kvec *vec,
				 size_t base)
{ … }

/**
 * xprt_sock_sendmsg - write an xdr_buf directly to a socket
 * @sock: open socket to send on
 * @msg: socket message metadata
 * @xdr: xdr_buf containing this request
 * @base: starting position in the buffer
 * @marker: stream record marker field
 * @sent_p: return the total number of bytes successfully queued for sending
 *
 * Return values:
 *   On success, returns zero and fills in @sent_p.
 *   %-ENOTSOCK if  @sock is not a struct socket.
 */
int xprt_sock_sendmsg(struct socket *sock, struct msghdr *msg,
		      struct xdr_buf *xdr, unsigned int base,
		      rpc_fraghdr marker, unsigned int *sent_p)
{ … }