Merge remote-tracking branch 'remotes/cohuck-gitlab/tags/s390x-20210409' into staging
[qemu/ar7.git] / net / checksum.c
blob70f4eaeb3a043ded7e90dc31a4b10bf10a77482c
1 /*
2 * IP checksumming functions.
3 * (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
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.
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.
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/>.
18 #include "qemu/osdep.h"
19 #include "net/checksum.h"
20 #include "net/eth.h"
22 uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq)
24 uint32_t sum1 = 0, sum2 = 0;
25 int i;
27 for (i = 0; i < len - 1; i += 2) {
28 sum1 += (uint32_t)buf[i];
29 sum2 += (uint32_t)buf[i + 1];
31 if (i < len) {
32 sum1 += (uint32_t)buf[i];
35 if (seq & 1) {
36 return sum1 + (sum2 << 8);
37 } else {
38 return sum2 + (sum1 << 8);
42 uint16_t net_checksum_finish(uint32_t sum)
44 while (sum>>16)
45 sum = (sum & 0xFFFF)+(sum >> 16);
46 return ~sum;
49 uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto,
50 uint8_t *addrs, uint8_t *buf)
52 uint32_t sum = 0;
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);
60 void net_checksum_calculate(uint8_t *data, int length, int csum_flag)
62 int mac_hdr_len, ip_len;
63 struct ip_header *ip;
64 uint16_t csum;
67 * Note: We cannot assume "data" is aligned, so the all code uses
68 * some macros that take care of possible unaligned access for
69 * struct members (just in case).
72 /* Ensure we have at least an Eth header */
73 if (length < sizeof(struct eth_header)) {
74 return;
77 /* Handle the optionnal VLAN headers */
78 switch (lduw_be_p(&PKT_GET_ETH_HDR(data)->h_proto)) {
79 case ETH_P_VLAN:
80 mac_hdr_len = sizeof(struct eth_header) +
81 sizeof(struct vlan_header);
82 break;
83 case ETH_P_DVLAN:
84 if (lduw_be_p(&PKT_GET_VLAN_HDR(data)->h_proto) == ETH_P_VLAN) {
85 mac_hdr_len = sizeof(struct eth_header) +
86 2 * sizeof(struct vlan_header);
87 } else {
88 mac_hdr_len = sizeof(struct eth_header) +
89 sizeof(struct vlan_header);
91 break;
92 default:
93 mac_hdr_len = sizeof(struct eth_header);
94 break;
97 length -= mac_hdr_len;
99 /* Now check we have an IP header (with an optionnal VLAN header) */
100 if (length < sizeof(struct ip_header)) {
101 return;
104 ip = (struct ip_header *)(data + mac_hdr_len);
106 if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) {
107 return; /* not IPv4 */
110 /* Calculate IP checksum */
111 if (csum_flag & CSUM_IP) {
112 stw_he_p(&ip->ip_sum, 0);
113 csum = net_raw_checksum((uint8_t *)ip, IP_HDR_GET_LEN(ip));
114 stw_be_p(&ip->ip_sum, csum);
117 if (IP4_IS_FRAGMENT(ip)) {
118 return; /* a fragmented IP packet */
121 ip_len = lduw_be_p(&ip->ip_len);
123 /* Last, check that we have enough data for the all IP frame */
124 if (length < ip_len) {
125 return;
128 ip_len -= IP_HDR_GET_LEN(ip);
130 switch (ip->ip_p) {
131 case IP_PROTO_TCP:
133 if (!(csum_flag & CSUM_TCP)) {
134 return;
137 tcp_header *tcp = (tcp_header *)(ip + 1);
139 if (ip_len < sizeof(tcp_header)) {
140 return;
143 /* Set csum to 0 */
144 stw_he_p(&tcp->th_sum, 0);
146 csum = net_checksum_tcpudp(ip_len, ip->ip_p,
147 (uint8_t *)&ip->ip_src,
148 (uint8_t *)tcp);
150 /* Store computed csum */
151 stw_be_p(&tcp->th_sum, csum);
153 break;
155 case IP_PROTO_UDP:
157 if (!(csum_flag & CSUM_UDP)) {
158 return;
161 udp_header *udp = (udp_header *)(ip + 1);
163 if (ip_len < sizeof(udp_header)) {
164 return;
167 /* Set csum to 0 */
168 stw_he_p(&udp->uh_sum, 0);
170 csum = net_checksum_tcpudp(ip_len, ip->ip_p,
171 (uint8_t *)&ip->ip_src,
172 (uint8_t *)udp);
174 /* Store computed csum */
175 stw_be_p(&udp->uh_sum, csum);
177 break;
179 default:
180 /* Can't handle any other protocol */
181 break;
185 uint32_t
186 net_checksum_add_iov(const struct iovec *iov, const unsigned int iov_cnt,
187 uint32_t iov_off, uint32_t size, uint32_t csum_offset)
189 size_t iovec_off, buf_off;
190 unsigned int i;
191 uint32_t res = 0;
193 iovec_off = 0;
194 buf_off = 0;
195 for (i = 0; i < iov_cnt && size; i++) {
196 if (iov_off < (iovec_off + iov[i].iov_len)) {
197 size_t len = MIN((iovec_off + iov[i].iov_len) - iov_off , size);
198 void *chunk_buf = iov[i].iov_base + (iov_off - iovec_off);
200 res += net_checksum_add_cont(len, chunk_buf, csum_offset);
201 csum_offset += len;
203 buf_off += len;
204 iov_off += len;
205 size -= len;
207 iovec_off += iov[i].iov_len;
209 return res;