| // 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/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, 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) |
| { |
| 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; |
| } |