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1 | 7200ac3c | Mark McLoughlin | /*
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2 | 7200ac3c | Mark McLoughlin | * IP checksumming functions.
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3 | 7200ac3c | Mark McLoughlin | * (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
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4 | 7200ac3c | Mark McLoughlin | *
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5 | 7200ac3c | Mark McLoughlin | * This program is free software; you can redistribute it and/or modify
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6 | 7200ac3c | Mark McLoughlin | * it under the terms of the GNU General Public License as published by
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7 | 4c32fe66 | Stefan Weil | * the Free Software Foundation; under version 2 or later of the License.
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8 | 7200ac3c | Mark McLoughlin | *
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9 | 7200ac3c | Mark McLoughlin | * This program is distributed in the hope that it will be useful,
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10 | 7200ac3c | Mark McLoughlin | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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11 | 7200ac3c | Mark McLoughlin | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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12 | 7200ac3c | Mark McLoughlin | * GNU General Public License for more details.
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13 | 7200ac3c | Mark McLoughlin | *
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14 | 7200ac3c | Mark McLoughlin | * You should have received a copy of the GNU General Public License
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15 | 7200ac3c | Mark McLoughlin | * along with this program; if not, see <http://www.gnu.org/licenses/>.
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16 | 7200ac3c | Mark McLoughlin | */
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17 | 7200ac3c | Mark McLoughlin | |
18 | 84026301 | Dmitry Fleytman | #include "qemu-common.h" |
19 | 7200ac3c | Mark McLoughlin | #include "net/checksum.h" |
20 | 7200ac3c | Mark McLoughlin | |
21 | 7200ac3c | Mark McLoughlin | #define PROTO_TCP 6 |
22 | 7200ac3c | Mark McLoughlin | #define PROTO_UDP 17 |
23 | 7200ac3c | Mark McLoughlin | |
24 | 5acf5ea4 | Dmitry Fleytman | uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq) |
25 | 7200ac3c | Mark McLoughlin | { |
26 | 7200ac3c | Mark McLoughlin | uint32_t sum = 0;
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27 | 7200ac3c | Mark McLoughlin | int i;
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28 | 7200ac3c | Mark McLoughlin | |
29 | 5acf5ea4 | Dmitry Fleytman | for (i = seq; i < seq + len; i++) {
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30 | 5acf5ea4 | Dmitry Fleytman | if (i & 1) { |
31 | 5acf5ea4 | Dmitry Fleytman | sum += (uint32_t)buf[i - seq]; |
32 | 5acf5ea4 | Dmitry Fleytman | } else {
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33 | 5acf5ea4 | Dmitry Fleytman | sum += (uint32_t)buf[i - seq] << 8;
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34 | 5acf5ea4 | Dmitry Fleytman | } |
35 | 7200ac3c | Mark McLoughlin | } |
36 | 7200ac3c | Mark McLoughlin | return sum;
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37 | 7200ac3c | Mark McLoughlin | } |
38 | 7200ac3c | Mark McLoughlin | |
39 | 7200ac3c | Mark McLoughlin | uint16_t net_checksum_finish(uint32_t sum) |
40 | 7200ac3c | Mark McLoughlin | { |
41 | 7200ac3c | Mark McLoughlin | while (sum>>16) |
42 | 7200ac3c | Mark McLoughlin | sum = (sum & 0xFFFF)+(sum >> 16); |
43 | 7200ac3c | Mark McLoughlin | return ~sum;
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44 | 7200ac3c | Mark McLoughlin | } |
45 | 7200ac3c | Mark McLoughlin | |
46 | 7200ac3c | Mark McLoughlin | uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto, |
47 | 7200ac3c | Mark McLoughlin | uint8_t *addrs, uint8_t *buf) |
48 | 7200ac3c | Mark McLoughlin | { |
49 | 7200ac3c | Mark McLoughlin | uint32_t sum = 0;
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50 | 7200ac3c | Mark McLoughlin | |
51 | 7200ac3c | Mark McLoughlin | sum += net_checksum_add(length, buf); // payload
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52 | 7200ac3c | Mark McLoughlin | sum += net_checksum_add(8, addrs); // src + dst address |
53 | 7200ac3c | Mark McLoughlin | sum += proto + length; // protocol & length
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54 | 7200ac3c | Mark McLoughlin | return net_checksum_finish(sum);
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55 | 7200ac3c | Mark McLoughlin | } |
56 | 7200ac3c | Mark McLoughlin | |
57 | 7200ac3c | Mark McLoughlin | void net_checksum_calculate(uint8_t *data, int length) |
58 | 7200ac3c | Mark McLoughlin | { |
59 | 7200ac3c | Mark McLoughlin | int hlen, plen, proto, csum_offset;
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60 | 7200ac3c | Mark McLoughlin | uint16_t csum; |
61 | 7200ac3c | Mark McLoughlin | |
62 | 7200ac3c | Mark McLoughlin | if ((data[14] & 0xf0) != 0x40) |
63 | 7200ac3c | Mark McLoughlin | return; /* not IPv4 */ |
64 | 7200ac3c | Mark McLoughlin | hlen = (data[14] & 0x0f) * 4; |
65 | 7200ac3c | Mark McLoughlin | plen = (data[16] << 8 | data[17]) - hlen; |
66 | 7200ac3c | Mark McLoughlin | proto = data[23];
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67 | 7200ac3c | Mark McLoughlin | |
68 | 7200ac3c | Mark McLoughlin | switch (proto) {
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69 | 7200ac3c | Mark McLoughlin | case PROTO_TCP:
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70 | 7200ac3c | Mark McLoughlin | csum_offset = 16;
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71 | 7200ac3c | Mark McLoughlin | break;
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72 | 7200ac3c | Mark McLoughlin | case PROTO_UDP:
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73 | 7200ac3c | Mark McLoughlin | csum_offset = 6;
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74 | 7200ac3c | Mark McLoughlin | break;
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75 | 7200ac3c | Mark McLoughlin | default:
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76 | 7200ac3c | Mark McLoughlin | return;
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77 | 7200ac3c | Mark McLoughlin | } |
78 | 7200ac3c | Mark McLoughlin | |
79 | 7200ac3c | Mark McLoughlin | if (plen < csum_offset+2) |
80 | 7200ac3c | Mark McLoughlin | return;
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81 | 7200ac3c | Mark McLoughlin | |
82 | 7200ac3c | Mark McLoughlin | data[14+hlen+csum_offset] = 0; |
83 | 7200ac3c | Mark McLoughlin | data[14+hlen+csum_offset+1] = 0; |
84 | 7200ac3c | Mark McLoughlin | csum = net_checksum_tcpudp(plen, proto, data+14+12, data+14+hlen); |
85 | 7200ac3c | Mark McLoughlin | data[14+hlen+csum_offset] = csum >> 8; |
86 | 7200ac3c | Mark McLoughlin | data[14+hlen+csum_offset+1] = csum & 0xff; |
87 | 7200ac3c | Mark McLoughlin | } |
88 | 84026301 | Dmitry Fleytman | |
89 | 84026301 | Dmitry Fleytman | uint32_t |
90 | 84026301 | Dmitry Fleytman | net_checksum_add_iov(const struct iovec *iov, const unsigned int iov_cnt, |
91 | 84026301 | Dmitry Fleytman | uint32_t iov_off, uint32_t size) |
92 | 84026301 | Dmitry Fleytman | { |
93 | 84026301 | Dmitry Fleytman | size_t iovec_off, buf_off; |
94 | 84026301 | Dmitry Fleytman | unsigned int i; |
95 | 84026301 | Dmitry Fleytman | uint32_t res = 0;
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96 | 84026301 | Dmitry Fleytman | uint32_t seq = 0;
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97 | 84026301 | Dmitry Fleytman | |
98 | 84026301 | Dmitry Fleytman | iovec_off = 0;
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99 | 84026301 | Dmitry Fleytman | buf_off = 0;
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100 | 84026301 | Dmitry Fleytman | for (i = 0; i < iov_cnt && size; i++) { |
101 | 84026301 | Dmitry Fleytman | if (iov_off < (iovec_off + iov[i].iov_len)) {
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102 | 84026301 | Dmitry Fleytman | size_t len = MIN((iovec_off + iov[i].iov_len) - iov_off , size); |
103 | 84026301 | Dmitry Fleytman | void *chunk_buf = iov[i].iov_base + (iov_off - iovec_off);
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104 | 84026301 | Dmitry Fleytman | |
105 | 84026301 | Dmitry Fleytman | res += net_checksum_add_cont(len, chunk_buf, seq); |
106 | 84026301 | Dmitry Fleytman | seq += len; |
107 | 84026301 | Dmitry Fleytman | |
108 | 84026301 | Dmitry Fleytman | buf_off += len; |
109 | 84026301 | Dmitry Fleytman | iov_off += len; |
110 | 84026301 | Dmitry Fleytman | size -= len; |
111 | 84026301 | Dmitry Fleytman | } |
112 | 84026301 | Dmitry Fleytman | iovec_off += iov[i].iov_len; |
113 | 84026301 | Dmitry Fleytman | } |
114 | 84026301 | Dmitry Fleytman | return res;
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115 | 84026301 | Dmitry Fleytman | } |