diff options
Diffstat (limited to '')
| -rw-r--r-- | net/sunrpc/socklib.c | 329 |
1 files changed, 329 insertions, 0 deletions
diff --git a/net/sunrpc/socklib.c b/net/sunrpc/socklib.c new file mode 100644 index 000000000..d52313af8 --- /dev/null +++ b/net/sunrpc/socklib.c @@ -0,0 +1,329 @@ +// 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 <okir@monad.swb.de> + */ + +#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/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, WRITE, 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) +{ + int err; + + err = xdr_alloc_bvec(xdr, GFP_KERNEL); + if (err < 0) + return err; + + iov_iter_bvec(&msg->msg_iter, WRITE, 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, WRITE, 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; +} |