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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 | // 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/xdr.h> #include <linux/export.h> /** * 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, 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 * */ 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); |