1 /* $NetBSD: in_cksum.c,v 1.10 2005/12/24 23:24:01 perry Exp $ */
2
3 /*
4 * Copyright 2001 Wasabi Systems, Inc.
5 * All rights reserved.
6 *
7 * Written by Simon Burge and Eduardo Horvath for Wasabi Systems, Inc.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed for the NetBSD Project by
20 * Wasabi Systems, Inc.
21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22 * or promote products derived from this software without specific prior
23 * written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
36 */
37
38 #include <sys/cdefs.h>
39 __KERNEL_RCSID(0, "$NetBSD: in_cksum.c,v 1.10 2005/12/24 23:24:01 perry Exp $");
40
41 #include <sys/param.h>
42 #include <sys/mbuf.h>
43 #include <sys/systm.h>
44 #include <netinet/in_systm.h>
45 #include <netinet/in.h>
46 #include <netinet/ip.h>
47 #include <netinet/ip_var.h>
48
49 /*
50 * Checksum routine for Internet Protocol family headers.
51 *
52 * This routine is very heavily used in the network
53 * code and should be modified for each CPU to be as fast as possible.
54 *
55 * PowerPC version.
56 */
57
58 #define REDUCE1 sum = (sum & 0xffff) + (sum >> 16)
59 /* Two REDUCE1s is faster than REDUCE1; if (sum > 65535) sum -= 65536; */
60 #define REDUCE { REDUCE1; REDUCE1; }
61
62 static inline int
in_cksum_internal(struct mbuf * m,int off,int len,u_int sum)63 in_cksum_internal(struct mbuf *m, int off, int len, u_int sum)
64 {
65 uint8_t *w;
66 int mlen = 0;
67 int byte_swapped = 0;
68 int n;
69
70 union {
71 uint8_t c[2];
72 uint16_t s;
73 } s_util;
74
75 for (;m && len; m = m->m_next) {
76 if (m->m_len == 0)
77 continue;
78 w = mtod(m, uint8_t *) + off;
79
80 /*
81 * 'off' can only be non-zero on the first pass of this
82 * loop when mlen != -1, so we don't need to worry about
83 * 'off' in the if clause below.
84 */
85 if (mlen == -1) {
86 /*
87 * The first byte of this mbuf is the continuation
88 * of a word spanning between this mbuf and the
89 * last mbuf.
90 *
91 * s_util.c[0] is already saved when scanning previous
92 * mbuf.
93 */
94 s_util.c[1] = *w++;
95 sum += s_util.s;
96 mlen = m->m_len - 1;
97 len--;
98 } else {
99 mlen = m->m_len - off;
100 off = 0;
101 }
102 if (len < mlen)
103 mlen = len;
104 len -= mlen;
105
106 /*
107 * Force to a word boundary.
108 */
109 if ((3 & (long) w) && (mlen > 0)) {
110 if ((1 & (long) w)) {
111 REDUCE;
112 sum <<= 8;
113 s_util.c[0] = *w++;
114 mlen--;
115 byte_swapped = 1;
116 }
117 if ((2 & (long) w) && (mlen > 1)) {
118 /*
119 * Since the `sum' may contain full 32 bit
120 * value, we can't simply add any value.
121 */
122 __asm volatile(
123 "lhz 7,0(%1);" /* load current data
124 half word */
125 "addc %0,%0,7;" /* add to sum */
126 "addze %0,%0;" /* add carry bit */
127 : "+r"(sum)
128 : "b"(w)
129 : "7"); /* clobber r7 */
130 w += 2;
131 mlen -= 2;
132 }
133 }
134
135 if (mlen >= 64) {
136 n = mlen >> 6;
137 __asm volatile(
138 "addic 0,0,0;" /* clear carry */
139 "mtctr %1;" /* load loop count */
140 "1:"
141 "lwz 7,4(%2);" /* load current data
142 word */
143 "lwz 8,8(%2);"
144 "lwz 9,12(%2);"
145 "lwz 10,16(%2);"
146 "adde %0,%0,7;" /* add to sum */
147 "adde %0,%0,8;"
148 "adde %0,%0,9;"
149 "adde %0,%0,10;"
150 "lwz 7,20(%2);"
151 "lwz 8,24(%2);"
152 "lwz 9,28(%2);"
153 "lwz 10,32(%2);"
154 "adde %0,%0,7;"
155 "adde %0,%0,8;"
156 "adde %0,%0,9;"
157 "adde %0,%0,10;"
158 "lwz 7,36(%2);"
159 "lwz 8,40(%2);"
160 "lwz 9,44(%2);"
161 "lwz 10,48(%2);"
162 "adde %0,%0,7;"
163 "adde %0,%0,8;"
164 "adde %0,%0,9;"
165 "adde %0,%0,10;"
166 "lwz 7,52(%2);"
167 "lwz 8,56(%2);"
168 "lwz 9,60(%2);"
169 "lwzu 10,64(%2);"
170 "adde %0,%0,7;"
171 "adde %0,%0,8;"
172 "adde %0,%0,9;"
173 "adde %0,%0,10;"
174 "bdnz 1b;" /* loop */
175 "addze %0,%0;" /* add carry bit */
176 : "+r"(sum)
177 : "r"(n), "b"(w - 4)
178 : "7", "8", "9", "10"); /* clobber r7, r8, r9,
179 r10 */
180 w += n * 64;
181 mlen -= n * 64;
182 }
183
184 if (mlen >= 8) {
185 n = mlen >> 3;
186 __asm volatile(
187 "addic 0,0,0;" /* clear carry */
188 "mtctr %1;" /* load loop count */
189 "1:"
190 "lwz 7,4(%2);" /* load current data
191 word */
192 "lwzu 8,8(%2);"
193 "adde %0,%0,7;" /* add to sum */
194 "adde %0,%0,8;"
195 "bdnz 1b;" /* loop */
196 "addze %0,%0;" /* add carry bit */
197 : "+r"(sum)
198 : "r"(n), "b"(w - 4)
199 : "7", "8"); /* clobber r7, r8 */
200 w += n * 8;
201 mlen -= n * 8;
202 }
203
204 if (mlen == 0 && byte_swapped == 0)
205 continue;
206 REDUCE;
207
208 while ((mlen -= 2) >= 0) {
209 sum += *(uint16_t *)w;
210 w += 2;
211 }
212
213 if (byte_swapped) {
214 REDUCE;
215 sum <<= 8;
216 byte_swapped = 0;
217 if (mlen == -1) {
218 s_util.c[1] = *w;
219 sum += s_util.s;
220 mlen = 0;
221 } else
222 mlen = -1;
223 } else if (mlen == -1)
224 s_util.c[0] = *w;
225 }
226 if (len)
227 printf("cksum: out of data\n");
228 if (mlen == -1) {
229 /* The last mbuf has odd # of bytes. Follow the
230 standard (the odd byte may be shifted left by 8 bits
231 or not as determined by endian-ness of the machine) */
232 s_util.c[1] = 0;
233 sum += s_util.s;
234 }
235 REDUCE;
236 return (~sum & 0xffff);
237 }
238
239 int
in_cksum(struct mbuf * m,int len)240 in_cksum(struct mbuf *m, int len)
241 {
242
243 return (in_cksum_internal(m, 0, len, 0));
244 }
245
246 int
in4_cksum(struct mbuf * m,uint8_t nxt,int off,int len)247 in4_cksum(struct mbuf *m, uint8_t nxt, int off, int len)
248 {
249 uint16_t *w;
250 u_int sum = 0;
251 union {
252 struct ipovly ipov;
253 u_int16_t w[10];
254 } u;
255
256 if (nxt != 0) {
257 /* pseudo header */
258 memset(&u.ipov, 0, sizeof(u.ipov));
259 u.ipov.ih_len = htons(len);
260 u.ipov.ih_pr = nxt;
261 u.ipov.ih_src = mtod(m, struct ip *)->ip_src;
262 u.ipov.ih_dst = mtod(m, struct ip *)->ip_dst;
263 w = u.w;
264 /* assumes sizeof(ipov) == 20 */
265 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; sum += w[4];
266 sum += w[5]; sum += w[6]; sum += w[7]; sum += w[8]; sum += w[9];
267 }
268
269 /* skip unnecessary part */
270 while (m && off > 0) {
271 if (m->m_len > off)
272 break;
273 off -= m->m_len;
274 m = m->m_next;
275 }
276
277 return (in_cksum_internal(m, off, len, sum));
278 }
279