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Commit | Line | Data |
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7200ac3c MM |
1 | /* |
2 | * IP checksumming functions. | |
3 | * (c) 2008 Gerd Hoffmann <kraxel@redhat.com> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
4c32fe66 | 7 | * the Free Software Foundation; under version 2 or later of the License. |
7200ac3c MM |
8 | * |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, see <http://www.gnu.org/licenses/>. | |
16 | */ | |
17 | ||
2744d920 | 18 | #include "qemu/osdep.h" |
84026301 | 19 | #include "qemu-common.h" |
7200ac3c | 20 | #include "net/checksum.h" |
50dbce65 | 21 | #include "net/eth.h" |
7200ac3c | 22 | |
5acf5ea4 | 23 | uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq) |
7200ac3c MM |
24 | { |
25 | uint32_t sum = 0; | |
26 | int i; | |
27 | ||
5acf5ea4 DF |
28 | for (i = seq; i < seq + len; i++) { |
29 | if (i & 1) { | |
30 | sum += (uint32_t)buf[i - seq]; | |
31 | } else { | |
32 | sum += (uint32_t)buf[i - seq] << 8; | |
33 | } | |
7200ac3c MM |
34 | } |
35 | return sum; | |
36 | } | |
37 | ||
38 | uint16_t net_checksum_finish(uint32_t sum) | |
39 | { | |
40 | while (sum>>16) | |
41 | sum = (sum & 0xFFFF)+(sum >> 16); | |
42 | return ~sum; | |
43 | } | |
44 | ||
45 | uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto, | |
46 | uint8_t *addrs, uint8_t *buf) | |
47 | { | |
48 | uint32_t sum = 0; | |
49 | ||
50 | sum += net_checksum_add(length, buf); // payload | |
51 | sum += net_checksum_add(8, addrs); // src + dst address | |
52 | sum += proto + length; // protocol & length | |
53 | return net_checksum_finish(sum); | |
54 | } | |
55 | ||
56 | void net_checksum_calculate(uint8_t *data, int length) | |
57 | { | |
ade6bad1 | 58 | int mac_hdr_len, ip_len; |
50dbce65 JCD |
59 | struct ip_header *ip; |
60 | ||
61 | /* | |
62 | * Note: We cannot assume "data" is aligned, so the all code uses | |
63 | * some macros that take care of possible unaligned access for | |
64 | * struct members (just in case). | |
65 | */ | |
7200ac3c | 66 | |
ade6bad1 JCD |
67 | /* Ensure we have at least an Eth header */ |
68 | if (length < sizeof(struct eth_header)) { | |
362786f1 PP |
69 | return; |
70 | } | |
71 | ||
ade6bad1 JCD |
72 | /* Handle the optionnal VLAN headers */ |
73 | switch (lduw_be_p(&PKT_GET_ETH_HDR(data)->h_proto)) { | |
74 | case ETH_P_VLAN: | |
75 | mac_hdr_len = sizeof(struct eth_header) + | |
76 | sizeof(struct vlan_header); | |
77 | break; | |
78 | case ETH_P_DVLAN: | |
79 | if (lduw_be_p(&PKT_GET_VLAN_HDR(data)->h_proto) == ETH_P_VLAN) { | |
80 | mac_hdr_len = sizeof(struct eth_header) + | |
81 | 2 * sizeof(struct vlan_header); | |
82 | } else { | |
83 | mac_hdr_len = sizeof(struct eth_header) + | |
84 | sizeof(struct vlan_header); | |
85 | } | |
86 | break; | |
87 | default: | |
88 | mac_hdr_len = sizeof(struct eth_header); | |
89 | break; | |
90 | } | |
91 | ||
92 | length -= mac_hdr_len; | |
93 | ||
94 | /* Now check we have an IP header (with an optionnal VLAN header) */ | |
95 | if (length < sizeof(struct ip_header)) { | |
96 | return; | |
97 | } | |
98 | ||
99 | ip = (struct ip_header *)(data + mac_hdr_len); | |
50dbce65 JCD |
100 | |
101 | if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) { | |
102 | return; /* not IPv4 */ | |
7200ac3c MM |
103 | } |
104 | ||
50dbce65 JCD |
105 | ip_len = lduw_be_p(&ip->ip_len); |
106 | ||
107 | /* Last, check that we have enough data for the all IP frame */ | |
108 | if (length < ip_len) { | |
362786f1 PP |
109 | return; |
110 | } | |
7200ac3c | 111 | |
50dbce65 JCD |
112 | ip_len -= IP_HDR_GET_LEN(ip); |
113 | ||
114 | switch (ip->ip_p) { | |
115 | case IP_PROTO_TCP: | |
116 | { | |
117 | uint16_t csum; | |
118 | tcp_header *tcp = (tcp_header *)(ip + 1); | |
119 | ||
120 | if (ip_len < sizeof(tcp_header)) { | |
121 | return; | |
122 | } | |
123 | ||
124 | /* Set csum to 0 */ | |
125 | stw_he_p(&tcp->th_sum, 0); | |
126 | ||
127 | csum = net_checksum_tcpudp(ip_len, ip->ip_p, | |
128 | (uint8_t *)&ip->ip_src, | |
129 | (uint8_t *)tcp); | |
130 | ||
131 | /* Store computed csum */ | |
132 | stw_be_p(&tcp->th_sum, csum); | |
133 | ||
134 | break; | |
135 | } | |
136 | case IP_PROTO_UDP: | |
137 | { | |
138 | uint16_t csum; | |
139 | udp_header *udp = (udp_header *)(ip + 1); | |
140 | ||
141 | if (ip_len < sizeof(udp_header)) { | |
142 | return; | |
143 | } | |
144 | ||
145 | /* Set csum to 0 */ | |
146 | stw_he_p(&udp->uh_sum, 0); | |
147 | ||
148 | csum = net_checksum_tcpudp(ip_len, ip->ip_p, | |
149 | (uint8_t *)&ip->ip_src, | |
150 | (uint8_t *)udp); | |
151 | ||
152 | /* Store computed csum */ | |
153 | stw_be_p(&udp->uh_sum, csum); | |
154 | ||
155 | break; | |
156 | } | |
157 | default: | |
158 | /* Can't handle any other protocol */ | |
159 | break; | |
160 | } | |
7200ac3c | 161 | } |
84026301 DF |
162 | |
163 | uint32_t | |
164 | net_checksum_add_iov(const struct iovec *iov, const unsigned int iov_cnt, | |
eb700029 | 165 | uint32_t iov_off, uint32_t size, uint32_t csum_offset) |
84026301 DF |
166 | { |
167 | size_t iovec_off, buf_off; | |
168 | unsigned int i; | |
169 | uint32_t res = 0; | |
84026301 DF |
170 | |
171 | iovec_off = 0; | |
172 | buf_off = 0; | |
173 | for (i = 0; i < iov_cnt && size; i++) { | |
174 | if (iov_off < (iovec_off + iov[i].iov_len)) { | |
175 | size_t len = MIN((iovec_off + iov[i].iov_len) - iov_off , size); | |
176 | void *chunk_buf = iov[i].iov_base + (iov_off - iovec_off); | |
177 | ||
eb700029 DF |
178 | res += net_checksum_add_cont(len, chunk_buf, csum_offset); |
179 | csum_offset += len; | |
84026301 DF |
180 | |
181 | buf_off += len; | |
182 | iov_off += len; | |
183 | size -= len; | |
184 | } | |
185 | iovec_off += iov[i].iov_len; | |
186 | } | |
187 | return res; | |
188 | } |