Annotation of src/sys/netinet6/in6_cksum.c, Revision 1.7
1.7 ! itojun 1: /* $NetBSD: in6_cksum.c,v 1.6 1999/12/13 15:17:22 itojun Exp $ */
1.3 thorpej 2:
1.2 itojun 3: /*
4: * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5: * All rights reserved.
6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
15: * 3. Neither the name of the project nor the names of its contributors
16: * may be used to endorse or promote products derived from this software
17: * without specific prior written permission.
18: *
19: * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22: * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29: * SUCH DAMAGE.
30: */
31:
32: /*
33: * Copyright (c) 1988, 1992, 1993
34: * The Regents of the University of California. All rights reserved.
35: *
36: * Redistribution and use in source and binary forms, with or without
37: * modification, are permitted provided that the following conditions
38: * are met:
39: * 1. Redistributions of source code must retain the above copyright
40: * notice, this list of conditions and the following disclaimer.
41: * 2. Redistributions in binary form must reproduce the above copyright
42: * notice, this list of conditions and the following disclaimer in the
43: * documentation and/or other materials provided with the distribution.
44: * 3. All advertising materials mentioning features or use of this software
45: * must display the following acknowledgement:
46: * This product includes software developed by the University of
47: * California, Berkeley and its contributors.
48: * 4. Neither the name of the University nor the names of its contributors
49: * may be used to endorse or promote products derived from this software
50: * without specific prior written permission.
51: *
52: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
53: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
56: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
62: * SUCH DAMAGE.
63: *
64: * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
65: */
66:
67: #include <sys/param.h>
68: #include <sys/mbuf.h>
69: #include <sys/systm.h>
70: #include <netinet/in.h>
1.7 ! itojun 71: #include <netinet/ip6.h>
1.2 itojun 72:
1.6 itojun 73: #include <net/net_osdep.h>
74:
1.2 itojun 75: /*
76: * Checksum routine for Internet Protocol family headers (Portable Version).
77: *
78: * This routine is very heavily used in the network
79: * code and should be modified for each CPU to be as fast as possible.
80: */
81:
82: #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
83: #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}
84:
85: static union {
1.5 itojun 86: u_int16_t phs[4];
1.2 itojun 87: struct {
1.5 itojun 88: u_int32_t ph_len;
89: u_int8_t ph_zero[3];
90: u_int8_t ph_nxt;
1.2 itojun 91: } ph;
92: } uph;
93:
94: /*
95: * m MUST contain a continuous IP6 header.
96: * off is a offset where TCP/UDP/ICMP6 header starts.
97: * len is a total length of a transport segment.
98: * (e.g. TCP header + TCP payload)
99: */
100:
101: int
102: in6_cksum(m, nxt, off, len)
103: register struct mbuf *m;
104: u_int8_t nxt;
1.6 itojun 105: u_int32_t off, len;
1.2 itojun 106: {
1.5 itojun 107: register u_int16_t *w;
1.2 itojun 108: register int sum = 0;
109: register int mlen = 0;
110: int byte_swapped = 0;
111: #if 0
112: int srcifid = 0, dstifid = 0;
113: #endif
114: struct ip6_hdr *ip6;
115:
116: union {
1.5 itojun 117: u_int8_t c[2];
118: u_int16_t s;
1.2 itojun 119: } s_util;
120: union {
1.5 itojun 121: u_int16_t s[2];
122: u_int32_t l;
1.2 itojun 123: } l_util;
124:
125: /* sanity check */
126: if (m->m_pkthdr.len < off + len) {
127: panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)\n",
128: m->m_pkthdr.len, off, len);
129: }
130:
131: /*
132: * First create IP6 pseudo header and calculate a summary.
133: */
134: ip6 = mtod(m, struct ip6_hdr *);
135: #if 0
136: if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
137: srcifid = ip6->ip6_src.s6_addr16[1];
138: ip6->ip6_src.s6_addr16[1] = 0;
139: }
140: if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
141: dstifid = ip6->ip6_dst.s6_addr16[1];
142: ip6->ip6_dst.s6_addr16[1] = 0;
143: }
144: #endif
1.5 itojun 145: w = (u_int16_t *)&ip6->ip6_src;
1.2 itojun 146: uph.ph.ph_len = htonl(len);
147: uph.ph.ph_nxt = nxt;
148:
149: /* IPv6 source address */
150: sum += w[0];
151: if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
152: sum += w[1];
153: sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5];
154: sum += w[6]; sum += w[7];
155: /* IPv6 destination address */
156: sum += w[8];
157: if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
158: sum += w[9];
159: sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13];
160: sum += w[14]; sum += w[15];
161: /* Payload length and upper layer identifier */
162: sum += uph.phs[0]; sum += uph.phs[1];
163: sum += uph.phs[2]; sum += uph.phs[3];
164:
165: #if 0
166: if (srcifid)
167: ip6->ip6_src.s6_addr16[1] = srcifid;
168: if (dstifid)
169: ip6->ip6_dst.s6_addr16[1] = dstifid;
170: #endif
171: /*
172: * Secondly calculate a summary of the first mbuf excluding offset.
173: */
174: while (m != NULL && off > 0) {
175: if (m->m_len <= off)
176: off -= m->m_len;
177: else
178: break;
179: m = m->m_next;
180: }
1.5 itojun 181: w = (u_int16_t *)(mtod(m, u_char *) + off);
1.2 itojun 182: mlen = m->m_len - off;
183: if (len < mlen)
184: mlen = len;
185: len -= mlen;
186: /*
187: * Force to even boundary.
188: */
1.4 itojun 189: if ((1 & (long) w) && (mlen > 0)) {
1.2 itojun 190: REDUCE;
191: sum <<= 8;
192: s_util.c[0] = *(u_char *)w;
1.5 itojun 193: w = (u_int16_t *)((char *)w + 1);
1.2 itojun 194: mlen--;
195: byte_swapped = 1;
196: }
197: /*
198: * Unroll the loop to make overhead from
199: * branches &c small.
200: */
201: while ((mlen -= 32) >= 0) {
202: sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
203: sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
204: sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
205: sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
206: w += 16;
207: }
208: mlen += 32;
209: while ((mlen -= 8) >= 0) {
210: sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
211: w += 4;
212: }
213: mlen += 8;
214: if (mlen == 0 && byte_swapped == 0)
215: goto next;
216: REDUCE;
217: while ((mlen -= 2) >= 0) {
218: sum += *w++;
219: }
220: if (byte_swapped) {
221: REDUCE;
222: sum <<= 8;
223: byte_swapped = 0;
224: if (mlen == -1) {
225: s_util.c[1] = *(char *)w;
226: sum += s_util.s;
227: mlen = 0;
228: } else
229: mlen = -1;
230: } else if (mlen == -1)
231: s_util.c[0] = *(char *)w;
232: next:
233: m = m->m_next;
234:
235: /*
236: * Lastly calculate a summary of the rest of mbufs.
237: */
238:
239: for (;m && len; m = m->m_next) {
240: if (m->m_len == 0)
241: continue;
1.5 itojun 242: w = mtod(m, u_int16_t *);
1.2 itojun 243: if (mlen == -1) {
244: /*
245: * The first byte of this mbuf is the continuation
246: * of a word spanning between this mbuf and the
247: * last mbuf.
248: *
249: * s_util.c[0] is already saved when scanning previous
250: * mbuf.
251: */
252: s_util.c[1] = *(char *)w;
253: sum += s_util.s;
1.5 itojun 254: w = (u_int16_t *)((char *)w + 1);
1.2 itojun 255: mlen = m->m_len - 1;
256: len--;
257: } else
258: mlen = m->m_len;
259: if (len < mlen)
260: mlen = len;
261: len -= mlen;
262: /*
263: * Force to even boundary.
264: */
1.4 itojun 265: if ((1 & (long) w) && (mlen > 0)) {
1.2 itojun 266: REDUCE;
267: sum <<= 8;
268: s_util.c[0] = *(u_char *)w;
1.5 itojun 269: w = (u_int16_t *)((char *)w + 1);
1.2 itojun 270: mlen--;
271: byte_swapped = 1;
272: }
273: /*
274: * Unroll the loop to make overhead from
275: * branches &c small.
276: */
277: while ((mlen -= 32) >= 0) {
278: sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
279: sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
280: sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
281: sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
282: w += 16;
283: }
284: mlen += 32;
285: while ((mlen -= 8) >= 0) {
286: sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
287: w += 4;
288: }
289: mlen += 8;
290: if (mlen == 0 && byte_swapped == 0)
291: continue;
292: REDUCE;
293: while ((mlen -= 2) >= 0) {
294: sum += *w++;
295: }
296: if (byte_swapped) {
297: REDUCE;
298: sum <<= 8;
299: byte_swapped = 0;
300: if (mlen == -1) {
301: s_util.c[1] = *(char *)w;
302: sum += s_util.s;
303: mlen = 0;
304: } else
305: mlen = -1;
306: } else if (mlen == -1)
307: s_util.c[0] = *(char *)w;
308: }
309: if (len)
310: panic("in6_cksum: out of data\n");
311: if (mlen == -1) {
312: /* The last mbuf has odd # of bytes. Follow the
313: standard (the odd byte may be shifted left by 8 bits
314: or not as determined by endian-ness of the machine) */
315: s_util.c[1] = 0;
316: sum += s_util.s;
317: }
318: REDUCE;
319: return (~sum & 0xffff);
320: }
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