1 /* $OpenBSD: in_cksum.c,v 1.11 2022/02/01 15:30:10 miod Exp $ */
2 /* $NetBSD: in_cksum.c,v 1.7 2003/07/15 02:54:48 lukem Exp $ */
3
4 /*
5 * Copyright 2001 Wasabi Systems, Inc.
6 * All rights reserved.
7 *
8 * Written by Simon Burge and Eduardo Horvath for Wasabi Systems, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed for the NetBSD Project by
21 * Wasabi Systems, Inc.
22 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
23 * or promote products derived from this software without specific prior
24 * written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/mbuf.h>
42 #include <sys/socketvar.h>
43
44 #include <netinet/in.h>
45 #include <netinet/ip.h>
46 #include <netinet/ip_var.h>
47
48 /*
49 * Checksum routine for Internet Protocol family headers.
50 *
51 * This routine is very heavily used in the network
52 * code and should be modified for each CPU to be as fast as possible.
53 *
54 * PowerPC version.
55 */
56
57 #define REDUCE1 sum = (sum & 0xffff) + (sum >> 16)
58 /* Two REDUCE1s is faster than REDUCE1; if (sum > 65535) sum -= 65536; */
59 #define REDUCE { REDUCE1; REDUCE1; }
60
61 static __inline__ int
in_cksum_internal(struct mbuf * m,int off,int len,u_int sum)62 in_cksum_internal(struct mbuf *m, int off, int len, u_int sum)
63 {
64 uint8_t *w;
65 int mlen = 0;
66 int byte_swapped = 0;
67 int n;
68
69 union {
70 uint8_t c[2];
71 uint16_t s;
72 } s_util;
73
74 for (;m && len; m = m->m_next) {
75 if (m->m_len == 0)
76 continue;
77 w = mtod(m, uint8_t *) + off;
78
79 /*
80 * 'off' can only be non-zero on the first pass of this
81 * loop when mlen != -1, so we don't need to worry about
82 * 'off' in the if clause below.
83 */
84 if (mlen == -1) {
85 /*
86 * The first byte of this mbuf is the continuation
87 * of a word spanning between this mbuf and the
88 * last mbuf.
89 *
90 * s_util.c[0] is already saved when scanning previous
91 * mbuf.
92 */
93 s_util.c[1] = *w++;
94 sum += s_util.s;
95 mlen = m->m_len - 1;
96 len--;
97 } else {
98 mlen = m->m_len - off;
99 off = 0;
100 }
101 if (len < mlen)
102 mlen = len;
103 len -= mlen;
104
105 /*
106 * Force to a word boundary.
107 */
108 if ((3 & (long) w) && (mlen > 0)) {
109 if ((1 & (long) w)) {
110 REDUCE;
111 sum <<= 8;
112 s_util.c[0] = *w++;
113 mlen--;
114 byte_swapped = 1;
115 }
116 if ((2 & (long) w) && (mlen > 1)) {
117 /*
118 * Since the `sum' may contain full 32 bit
119 * value, we can't simply add any value.
120 */
121 __asm volatile(
122 "lhz 7,0(%1);" /* load current data
123 half word */
124 "addc %0,%0,7;" /* add to sum */
125 "addze %0,%0;" /* add carry bit */
126 : "+r"(sum)
127 : "b"(w)
128 : "7"); /* clobber r7 */
129 w += 2;
130 mlen -= 2;
131 }
132 }
133
134 if (mlen >= 64) {
135 n = mlen >> 6;
136 __asm volatile(
137 "addic 0,0,0;" /* clear carry */
138 "mtctr %1;" /* load loop count */
139 "1:"
140 "lwz 7,4(%2);" /* load current data
141 word */
142 "lwz 8,8(%2);"
143 "lwz 9,12(%2);"
144 "lwz 10,16(%2);"
145 "adde %0,%0,7;" /* add to sum */
146 "adde %0,%0,8;"
147 "adde %0,%0,9;"
148 "adde %0,%0,10;"
149 "lwz 7,20(%2);"
150 "lwz 8,24(%2);"
151 "lwz 9,28(%2);"
152 "lwz 10,32(%2);"
153 "adde %0,%0,7;"
154 "adde %0,%0,8;"
155 "adde %0,%0,9;"
156 "adde %0,%0,10;"
157 "lwz 7,36(%2);"
158 "lwz 8,40(%2);"
159 "lwz 9,44(%2);"
160 "lwz 10,48(%2);"
161 "adde %0,%0,7;"
162 "adde %0,%0,8;"
163 "adde %0,%0,9;"
164 "adde %0,%0,10;"
165 "lwz 7,52(%2);"
166 "lwz 8,56(%2);"
167 "lwz 9,60(%2);"
168 "lwzu 10,64(%2);"
169 "adde %0,%0,7;"
170 "adde %0,%0,8;"
171 "adde %0,%0,9;"
172 "adde %0,%0,10;"
173 "bdnz 1b;" /* loop */
174 "addze %0,%0;" /* add carry bit */
175 : "+r"(sum)
176 : "r"(n), "b"(w - 4)
177 : "7", "8", "9", "10"); /* clobber r7, r8, r9,
178 r10 */
179 w += n * 64;
180 mlen -= n * 64;
181 }
182
183 if (mlen >= 8) {
184 n = mlen >> 3;
185 __asm volatile(
186 "addic 0,0,0;" /* clear carry */
187 "mtctr %1;" /* load loop count */
188 "1:"
189 "lwz 7,4(%2);" /* load current data
190 word */
191 "lwzu 8,8(%2);"
192 "adde %0,%0,7;" /* add to sum */
193 "adde %0,%0,8;"
194 "bdnz 1b;" /* loop */
195 "addze %0,%0;" /* add carry bit */
196 : "+r"(sum)
197 : "r"(n), "b"(w - 4)
198 : "7", "8"); /* clobber r7, r8 */
199 w += n * 8;
200 mlen -= n * 8;
201 }
202
203 if (mlen == 0 && byte_swapped == 0)
204 continue;
205 REDUCE;
206
207 while ((mlen -= 2) >= 0) {
208 sum += *(uint16_t *)w;
209 w += 2;
210 }
211
212 if (byte_swapped) {
213 REDUCE;
214 sum <<= 8;
215 byte_swapped = 0;
216 if (mlen == -1) {
217 s_util.c[1] = *w;
218 sum += s_util.s;
219 mlen = 0;
220 } else
221 mlen = -1;
222 } else if (mlen == -1)
223 s_util.c[0] = *w;
224 }
225 if (len)
226 printf("cksum: out of data\n");
227 if (mlen == -1) {
228 /* The last mbuf has odd # of bytes. Follow the
229 standard (the odd byte may be shifted left by 8 bits
230 or not as determined by endian-ness of the machine) */
231 s_util.c[1] = 0;
232 sum += s_util.s;
233 }
234 REDUCE;
235 return (~sum & 0xffff);
236 }
237
238 int
in_cksum(struct mbuf * m,int len)239 in_cksum(struct mbuf *m, int len)
240 {
241
242 return (in_cksum_internal(m, 0, len, 0));
243 }
244
245 int
in4_cksum(struct mbuf * m,uint8_t nxt,int off,int len)246 in4_cksum(struct mbuf *m, uint8_t nxt, int off, int len)
247 {
248 uint16_t *w;
249 u_int sum = 0;
250 union {
251 struct ipovly ipov;
252 u_int16_t w[10];
253 } u;
254
255 if (nxt != 0) {
256 /* pseudo header */
257 u.ipov.ih_x1[8] = 0;
258 u.ipov.ih_pr = nxt;
259 u.ipov.ih_len = htons(len);
260 u.ipov.ih_src = mtod(m, struct ip *)->ip_src;
261 u.ipov.ih_dst = mtod(m, struct ip *)->ip_dst;
262 w = u.w;
263 /* assumes sizeof(ipov) == 20 and first 8 bytes are zeroes */
264 sum += w[4]; sum += w[5]; sum += w[6];
265 sum += w[7]; sum += w[8]; sum += w[9];
266 }
267
268 /* skip unnecessary part */
269 while (m && off > 0) {
270 if (m->m_len > off)
271 break;
272 off -= m->m_len;
273 m = m->m_next;
274 }
275
276 return (in_cksum_internal(m, off, len, sum));
277 }
278