// 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 {
struct sk_buff *skb;
unsigned int offset;
size_t count;
__wsum csum;
};
typedef size_t (*xdr_skb_read_actor)(struct xdr_skb_reader *desc, void *to,
size_t len);
/**
* 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)
{
if (len > desc->count)
len = desc->count;
if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
return 0;
desc->count -= len;
desc->offset += len;
return 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)
{
unsigned int pos;
__wsum csum2;
if (len > desc->count)
len = desc->count;
pos = desc->offset;
csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len);
desc->csum = csum_block_add(desc->csum, csum2, pos);
desc->count -= len;
desc->offset += len;
return 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)
{
struct page **ppage = xdr->pages;
unsigned int len, pglen = xdr->page_len;
ssize_t copied = 0;
size_t ret;
len = xdr->head[0].iov_len;
if (base < len) {
len -= base;
ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
copied += ret;
if (ret != len || !desc->count)
goto out;
base = 0;
} else
base -= len;
if (unlikely(pglen == 0))
goto copy_tail;
if (unlikely(base >= pglen)) {
base -= pglen;
goto copy_tail;
}
if (base || xdr->page_base) {
pglen -= base;
base += xdr->page_base;
ppage += base >> PAGE_SHIFT;
base &= ~PAGE_MASK;
}
do {
char *kaddr;
/* ACL likes to be lazy in allocating pages - ACLs
* are small by default but can get huge. */
if ((xdr->flags & XDRBUF_SPARSE_PAGES) && *ppage == NULL) {
*ppage = alloc_page(GFP_NOWAIT | __GFP_NOWARN);
if (unlikely(*ppage == NULL)) {
if (copied == 0)
copied = -ENOMEM;
goto out;
}
}
len = PAGE_SIZE;
kaddr = kmap_atomic(*ppage);
if (base) {
len -= base;
if (pglen < len)
len = pglen;
ret = copy_actor(desc, kaddr + base, len);
base = 0;
} else {
if (pglen < len)
len = pglen;
ret = copy_actor(desc, kaddr, len);
}
flush_dcache_page(*ppage);
kunmap_atomic(kaddr);
copied += ret;
if (ret != len || !desc->count)
goto out;
ppage++;
} while ((pglen -= len) != 0);
copy_tail:
len = xdr->tail[0].iov_len;
if (base < len)
copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
out:
return copied;
}
/**
* 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)
{
struct xdr_skb_reader desc;
desc.skb = skb;
desc.offset = 0;
desc.count = skb->len - desc.offset;
if (skb_csum_unnecessary(skb))
goto no_checksum;
desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
return -1;
if (desc.offset != skb->len) {
__wsum csum2;
csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
}
if (desc.count)
return -1;
if (csum_fold(desc.csum))
return -1;
if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
!skb->csum_complete_sw)
netdev_rx_csum_fault(skb->dev, skb);
return 0;
no_checksum:
if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
return -1;
if (desc.count)
return -1;
return 0;
}
EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr);
static inline int xprt_sendmsg(struct socket *sock, struct msghdr *msg,
size_t seek)
{
if (seek)
iov_iter_advance(&msg->msg_iter, seek);
return sock_sendmsg(sock, msg);
}
static int xprt_send_kvec(struct socket *sock, struct msghdr *msg,
struct kvec *vec, size_t seek)
{
iov_iter_kvec(&msg->msg_iter, ITER_SOURCE, vec, 1, vec->iov_len);
return xprt_sendmsg(sock, msg, seek);
}
static int xprt_send_pagedata(struct socket *sock, struct msghdr *msg,
struct xdr_buf *xdr, size_t base)
{
iov_iter_bvec(&msg->msg_iter, ITER_SOURCE, xdr->bvec, xdr_buf_pagecount(xdr),
xdr->page_len + xdr->page_base);
return xprt_sendmsg(sock, msg, base + xdr->page_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)
{
struct kvec iov[2] = {
[0] = {
.iov_base = &marker,
.iov_len = sizeof(marker)
},
[1] = *vec,
};
size_t len = iov[0].iov_len + iov[1].iov_len;
iov_iter_kvec(&msg->msg_iter, ITER_SOURCE, iov, 2, len);
return xprt_sendmsg(sock, msg, 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)
{
unsigned int rmsize = marker ? sizeof(marker) : 0;
unsigned int remainder = rmsize + xdr->len - base;
unsigned int want;
int err = 0;
*sent_p = 0;
if (unlikely(!sock))
return -ENOTSOCK;
msg->msg_flags |= MSG_MORE;
want = xdr->head[0].iov_len + rmsize;
if (base < want) {
unsigned int len = want - base;
remainder -= len;
if (remainder == 0)
msg->msg_flags &= ~MSG_MORE;
if (rmsize)
err = xprt_send_rm_and_kvec(sock, msg, marker,
&xdr->head[0], base);
else
err = xprt_send_kvec(sock, msg, &xdr->head[0], base);
if (remainder == 0 || err != len)
goto out;
*sent_p += err;
base = 0;
} else {
base -= want;
}
if (base < xdr->page_len) {
unsigned int len = xdr->page_len - base;
remainder -= len;
if (remainder == 0)
msg->msg_flags &= ~MSG_MORE;
err = xprt_send_pagedata(sock, msg, xdr, base);
if (remainder == 0 || err != len)
goto out;
*sent_p += err;
base = 0;
} else {
base -= xdr->page_len;
}
if (base >= xdr->tail[0].iov_len)
return 0;
msg->msg_flags &= ~MSG_MORE;
err = xprt_send_kvec(sock, msg, &xdr->tail[0], base);
out:
if (err > 0) {
*sent_p += err;
err = 0;
}
return err;
}
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