Merge remote-tracking branch 'remotes/rth/tags/pull-pa-20200127' into staging
[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 "net/checksum.h"
20 #include "net/eth.h"
21
22 uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq)
23 {
24 uint32_t sum1 = 0, sum2 = 0;
25 int i;
26
27 for (i = 0; i < len - 1; i += 2) {
28 sum1 += (uint32_t)buf[i];
29 sum2 += (uint32_t)buf[i + 1];
30 }
31 if (i < len) {
32 sum1 += (uint32_t)buf[i];
33 }
34
35 if (seq & 1) {
36 return sum1 + (sum2 << 8);
37 } else {
38 return sum2 + (sum1 << 8);
39 }
40 }
41
42 uint16_t net_checksum_finish(uint32_t sum)
43 {
44 while (sum>>16)
45 sum = (sum & 0xFFFF)+(sum >> 16);
46 return ~sum;
47 }
48
49 uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto,
50 uint8_t *addrs, uint8_t *buf)
51 {
52 uint32_t sum = 0;
53
54 sum += net_checksum_add(length, buf); // payload
55 sum += net_checksum_add(8, addrs); // src + dst address
56 sum += proto + length; // protocol & length
57 return net_checksum_finish(sum);
58 }
59
60 void net_checksum_calculate(uint8_t *data, int length)
61 {
62 int mac_hdr_len, ip_len;
63 struct ip_header *ip;
64
65 /*
66 * Note: We cannot assume "data" is aligned, so the all code uses
67 * some macros that take care of possible unaligned access for
68 * struct members (just in case).
69 */
70
71 /* Ensure we have at least an Eth header */
72 if (length < sizeof(struct eth_header)) {
73 return;
74 }
75
76 /* Handle the optionnal VLAN headers */
77 switch (lduw_be_p(&PKT_GET_ETH_HDR(data)->h_proto)) {
78 case ETH_P_VLAN:
79 mac_hdr_len = sizeof(struct eth_header) +
80 sizeof(struct vlan_header);
81 break;
82 case ETH_P_DVLAN:
83 if (lduw_be_p(&PKT_GET_VLAN_HDR(data)->h_proto) == ETH_P_VLAN) {
84 mac_hdr_len = sizeof(struct eth_header) +
85 2 * sizeof(struct vlan_header);
86 } else {
87 mac_hdr_len = sizeof(struct eth_header) +
88 sizeof(struct vlan_header);
89 }
90 break;
91 default:
92 mac_hdr_len = sizeof(struct eth_header);
93 break;
94 }
95
96 length -= mac_hdr_len;
97
98 /* Now check we have an IP header (with an optionnal VLAN header) */
99 if (length < sizeof(struct ip_header)) {
100 return;
101 }
102
103 ip = (struct ip_header *)(data + mac_hdr_len);
104
105 if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) {
106 return; /* not IPv4 */
107 }
108
109 ip_len = lduw_be_p(&ip->ip_len);
110
111 /* Last, check that we have enough data for the all IP frame */
112 if (length < ip_len) {
113 return;
114 }
115
116 ip_len -= IP_HDR_GET_LEN(ip);
117
118 switch (ip->ip_p) {
119 case IP_PROTO_TCP:
120 {
121 uint16_t csum;
122 tcp_header *tcp = (tcp_header *)(ip + 1);
123
124 if (ip_len < sizeof(tcp_header)) {
125 return;
126 }
127
128 /* Set csum to 0 */
129 stw_he_p(&tcp->th_sum, 0);
130
131 csum = net_checksum_tcpudp(ip_len, ip->ip_p,
132 (uint8_t *)&ip->ip_src,
133 (uint8_t *)tcp);
134
135 /* Store computed csum */
136 stw_be_p(&tcp->th_sum, csum);
137
138 break;
139 }
140 case IP_PROTO_UDP:
141 {
142 uint16_t csum;
143 udp_header *udp = (udp_header *)(ip + 1);
144
145 if (ip_len < sizeof(udp_header)) {
146 return;
147 }
148
149 /* Set csum to 0 */
150 stw_he_p(&udp->uh_sum, 0);
151
152 csum = net_checksum_tcpudp(ip_len, ip->ip_p,
153 (uint8_t *)&ip->ip_src,
154 (uint8_t *)udp);
155
156 /* Store computed csum */
157 stw_be_p(&udp->uh_sum, csum);
158
159 break;
160 }
161 default:
162 /* Can't handle any other protocol */
163 break;
164 }
165 }
166
167 uint32_t
168 net_checksum_add_iov(const struct iovec *iov, const unsigned int iov_cnt,
169 uint32_t iov_off, uint32_t size, uint32_t csum_offset)
170 {
171 size_t iovec_off, buf_off;
172 unsigned int i;
173 uint32_t res = 0;
174
175 iovec_off = 0;
176 buf_off = 0;
177 for (i = 0; i < iov_cnt && size; i++) {
178 if (iov_off < (iovec_off + iov[i].iov_len)) {
179 size_t len = MIN((iovec_off + iov[i].iov_len) - iov_off , size);
180 void *chunk_buf = iov[i].iov_base + (iov_off - iovec_off);
181
182 res += net_checksum_add_cont(len, chunk_buf, csum_offset);
183 csum_offset += len;
184
185 buf_off += len;
186 iov_off += len;
187 size -= len;
188 }
189 iovec_off += iov[i].iov_len;
190 }
191 return res;
192 }