tests: virtio-9p: rename PCI configuration test
[qemu.git] / net / checksum.c
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
7 * the Free Software Foundation; under version 2 or later of the License.
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
18 #include "qemu/osdep.h"
19 #include "qemu-common.h"
20 #include "net/checksum.h"
21 #include "net/eth.h"
22
23 uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq)
24 {
25 uint32_t sum = 0;
26 int i;
27
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 }
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 {
58 int mac_hdr_len, ip_len;
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 */
66
67 /* Ensure we have at least an Eth header */
68 if (length < sizeof(struct eth_header)) {
69 return;
70 }
71
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);
100
101 if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) {
102 return; /* not IPv4 */
103 }
104
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) {
109 return;
110 }
111
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 }
161 }
162
163 uint32_t
164 net_checksum_add_iov(const struct iovec *iov, const unsigned int iov_cnt,
165 uint32_t iov_off, uint32_t size, uint32_t csum_offset)
166 {
167 size_t iovec_off, buf_off;
168 unsigned int i;
169 uint32_t res = 0;
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
178 res += net_checksum_add_cont(len, chunk_buf, csum_offset);
179 csum_offset += len;
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 }