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Mark McLoughlin7200ac32009-10-22 17:49:03 +01001/*
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
Stefan Weil4c32fe62012-01-27 17:40:43 +01007 * the Free Software Foundation; under version 2 or later of the License.
Mark McLoughlin7200ac32009-10-22 17:49:03 +01008 *
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/>.
Mark McLoughlin7200ac32009-10-22 17:49:03 +010016 */
17
Peter Maydell2744d922016-01-29 17:50:00 +000018#include "qemu/osdep.h"
Mark McLoughlin7200ac32009-10-22 17:49:03 +010019#include "net/checksum.h"
Jean-Christophe Dubois50dbce62016-05-30 19:25:46 +020020#include "net/eth.h"
Mark McLoughlin7200ac32009-10-22 17:49:03 +010021
Dmitry Fleytman5acf5ea2013-03-09 11:21:02 +020022uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq)
Mark McLoughlin7200ac32009-10-22 17:49:03 +010023{
Ladi Prosekd5aa3e62017-01-06 09:08:53 +010024 uint32_t sum1 = 0, sum2 = 0;
Mark McLoughlin7200ac32009-10-22 17:49:03 +010025 int i;
26
Ladi Prosekd5aa3e62017-01-06 09:08:53 +010027 for (i = 0; i < len - 1; i += 2) {
28 sum1 += (uint32_t)buf[i];
29 sum2 += (uint32_t)buf[i + 1];
Mark McLoughlin7200ac32009-10-22 17:49:03 +010030 }
Ladi Prosekd5aa3e62017-01-06 09:08:53 +010031 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 }
Mark McLoughlin7200ac32009-10-22 17:49:03 +010040}
41
42uint16_t net_checksum_finish(uint32_t sum)
43{
44 while (sum>>16)
Paolo Bonzini7d374352018-12-13 23:37:37 +010045 sum = (sum & 0xFFFF)+(sum >> 16);
Mark McLoughlin7200ac32009-10-22 17:49:03 +010046 return ~sum;
47}
48
49uint16_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
Bin Mengf5746332020-12-11 17:35:12 +080060void net_checksum_calculate(uint8_t *data, int length, int csum_flag)
Mark McLoughlin7200ac32009-10-22 17:49:03 +010061{
Jean-Christophe Duboisade6bad2016-05-30 19:25:48 +020062 int mac_hdr_len, ip_len;
Jean-Christophe Dubois50dbce62016-05-30 19:25:46 +020063 struct ip_header *ip;
Guishan Qind97f1152020-12-11 17:35:11 +080064 uint16_t csum;
Jean-Christophe Dubois50dbce62016-05-30 19:25:46 +020065
66 /*
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).
70 */
Mark McLoughlin7200ac32009-10-22 17:49:03 +010071
Jean-Christophe Duboisade6bad2016-05-30 19:25:48 +020072 /* Ensure we have at least an Eth header */
73 if (length < sizeof(struct eth_header)) {
Prasad J Pandit362786f2016-03-02 17:29:58 +053074 return;
75 }
76
Michael Tokarev0a19d872023-07-14 14:33:49 +030077 /* Handle the optional VLAN headers */
Jean-Christophe Duboisade6bad2016-05-30 19:25:48 +020078 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);
90 }
91 break;
92 default:
93 mac_hdr_len = sizeof(struct eth_header);
94 break;
95 }
96
97 length -= mac_hdr_len;
98
Michael Tokarev0a19d872023-07-14 14:33:49 +030099 /* Now check we have an IP header (with an optional VLAN header) */
Jean-Christophe Duboisade6bad2016-05-30 19:25:48 +0200100 if (length < sizeof(struct ip_header)) {
101 return;
102 }
103
104 ip = (struct ip_header *)(data + mac_hdr_len);
Mark McLoughlin7200ac32009-10-22 17:49:03 +0100105
Jean-Christophe Dubois50dbce62016-05-30 19:25:46 +0200106 if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) {
107 return; /* not IPv4 */
108 }
109
Guishan Qind97f1152020-12-11 17:35:11 +0800110 /* Calculate IP checksum */
Bin Mengf5746332020-12-11 17:35:12 +0800111 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);
115 }
Guishan Qind97f1152020-12-11 17:35:11 +0800116
Markus Carlstedt0dcf0c02020-12-11 17:35:10 +0800117 if (IP4_IS_FRAGMENT(ip)) {
118 return; /* a fragmented IP packet */
119 }
120
Jean-Christophe Dubois50dbce62016-05-30 19:25:46 +0200121 ip_len = lduw_be_p(&ip->ip_len);
122
123 /* Last, check that we have enough data for the all IP frame */
124 if (length < ip_len) {
125 return;
126 }
127
128 ip_len -= IP_HDR_GET_LEN(ip);
129
130 switch (ip->ip_p) {
131 case IP_PROTO_TCP:
132 {
Bin Mengf5746332020-12-11 17:35:12 +0800133 if (!(csum_flag & CSUM_TCP)) {
134 return;
135 }
136
Jean-Christophe Dubois50dbce62016-05-30 19:25:46 +0200137 tcp_header *tcp = (tcp_header *)(ip + 1);
138
139 if (ip_len < sizeof(tcp_header)) {
140 return;
141 }
142
143 /* Set csum to 0 */
144 stw_he_p(&tcp->th_sum, 0);
145
146 csum = net_checksum_tcpudp(ip_len, ip->ip_p,
147 (uint8_t *)&ip->ip_src,
148 (uint8_t *)tcp);
149
150 /* Store computed csum */
151 stw_be_p(&tcp->th_sum, csum);
152
153 break;
154 }
155 case IP_PROTO_UDP:
156 {
Bin Mengf5746332020-12-11 17:35:12 +0800157 if (!(csum_flag & CSUM_UDP)) {
158 return;
159 }
160
Jean-Christophe Dubois50dbce62016-05-30 19:25:46 +0200161 udp_header *udp = (udp_header *)(ip + 1);
162
163 if (ip_len < sizeof(udp_header)) {
164 return;
165 }
166
167 /* Set csum to 0 */
168 stw_he_p(&udp->uh_sum, 0);
169
170 csum = net_checksum_tcpudp(ip_len, ip->ip_p,
171 (uint8_t *)&ip->ip_src,
172 (uint8_t *)udp);
173
174 /* Store computed csum */
175 stw_be_p(&udp->uh_sum, csum);
176
177 break;
178 }
Mark McLoughlin7200ac32009-10-22 17:49:03 +0100179 default:
Jean-Christophe Dubois50dbce62016-05-30 19:25:46 +0200180 /* Can't handle any other protocol */
181 break;
Mark McLoughlin7200ac32009-10-22 17:49:03 +0100182 }
Mark McLoughlin7200ac32009-10-22 17:49:03 +0100183}
Dmitry Fleytman84026302013-03-09 11:21:03 +0200184
185uint32_t
186net_checksum_add_iov(const struct iovec *iov, const unsigned int iov_cnt,
Dmitry Fleytmaneb700022016-06-01 11:23:41 +0300187 uint32_t iov_off, uint32_t size, uint32_t csum_offset)
Dmitry Fleytman84026302013-03-09 11:21:03 +0200188{
Richard Hendersonfe4bd912021-07-12 18:43:58 +0000189 size_t iovec_off;
Dmitry Fleytman84026302013-03-09 11:21:03 +0200190 unsigned int i;
191 uint32_t res = 0;
Dmitry Fleytman84026302013-03-09 11:21:03 +0200192
193 iovec_off = 0;
Dmitry Fleytman84026302013-03-09 11:21:03 +0200194 for (i = 0; i < iov_cnt && size; i++) {
195 if (iov_off < (iovec_off + iov[i].iov_len)) {
196 size_t len = MIN((iovec_off + iov[i].iov_len) - iov_off , size);
197 void *chunk_buf = iov[i].iov_base + (iov_off - iovec_off);
198
Dmitry Fleytmaneb700022016-06-01 11:23:41 +0300199 res += net_checksum_add_cont(len, chunk_buf, csum_offset);
200 csum_offset += len;
Dmitry Fleytman84026302013-03-09 11:21:03 +0200201
Dmitry Fleytman84026302013-03-09 11:21:03 +0200202 iov_off += len;
203 size -= len;
204 }
205 iovec_off += iov[i].iov_len;
206 }
207 return res;
208}