diff options
Diffstat (limited to 'net/sunrpc/socklib.c')
| -rw-r--r-- | net/sunrpc/socklib.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/net/sunrpc/socklib.c b/net/sunrpc/socklib.c new file mode 100644 index 00000000000..8f97e90f36c --- /dev/null +++ b/net/sunrpc/socklib.c @@ -0,0 +1,175 @@ +/* + * 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/types.h> +#include <linux/pagemap.h> +#include <linux/udp.h> +#include <linux/sunrpc/xdr.h> + + +/** + * 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 skb_read_bits(skb_reader_t *desc, void *to, size_t len) +{ + if (len > desc->count) + len = desc->count; + if (skb_copy_bits(desc->skb, desc->offset, to, len)) + return 0; + desc->count -= len; + desc->offset += len; + return len; +} + +/** + * 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 skb_read_and_csum_bits(skb_reader_t *desc, void *to, size_t len) +{ + unsigned int csum2, pos; + + if (len > desc->count) + len = desc->count; + pos = desc->offset; + csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0); + 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 + * + */ +ssize_t xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, skb_reader_t *desc, skb_read_actor_t copy_actor) +{ + struct page **ppage = xdr->pages; + unsigned int len, pglen = xdr->page_len; + ssize_t copied = 0; + int 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_CACHE_SHIFT; + base &= ~PAGE_CACHE_MASK; + } + do { + char *kaddr; + + /* ACL likes to be lazy in allocating pages - ACLs + * are small by default but can get huge. */ + if (unlikely(*ppage == NULL)) { + *ppage = alloc_page(GFP_ATOMIC); + if (unlikely(*ppage == NULL)) { + if (copied == 0) + copied = -ENOMEM; + goto out; + } + } + + len = PAGE_CACHE_SIZE; + kaddr = kmap_atomic(*ppage, KM_SKB_SUNRPC_DATA); + 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, KM_SKB_SUNRPC_DATA); + 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) +{ + skb_reader_t desc; + + desc.skb = skb; + desc.offset = sizeof(struct udphdr); + desc.count = skb->len - desc.offset; + + if (skb->ip_summed == CHECKSUM_UNNECESSARY) + goto no_checksum; + + desc.csum = csum_partial(skb->data, desc.offset, skb->csum); + if (xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_and_csum_bits) < 0) + return -1; + if (desc.offset != skb->len) { + unsigned int 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 ((unsigned short)csum_fold(desc.csum)) + return -1; + return 0; +no_checksum: + if (xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_bits) < 0) + return -1; + if (desc.count) + return -1; + return 0; +} |