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1.1 nbrk 1: /* $OpenBSD: uipc_mbuf.c,v 1.85 2007/07/20 09:59:19 claudio Exp $ */
2: /* $NetBSD: uipc_mbuf.c,v 1.15.4.1 1996/06/13 17:11:44 cgd Exp $ */
3:
4: /*
5: * Copyright (c) 1982, 1986, 1988, 1991, 1993
6: * The Regents of the University of California. All rights reserved.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: * 3. Neither the name of the University nor the names of its contributors
17: * may be used to endorse or promote products derived from this software
18: * without specific prior written permission.
19: *
20: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30: * SUCH DAMAGE.
31: *
32: * @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94
33: */
34:
35: /*
36: * @(#)COPYRIGHT 1.1 (NRL) 17 January 1995
37: *
38: * NRL grants permission for redistribution and use in source and binary
39: * forms, with or without modification, of the software and documentation
40: * created at NRL provided that the following conditions are met:
41: *
42: * 1. Redistributions of source code must retain the above copyright
43: * notice, this list of conditions and the following disclaimer.
44: * 2. Redistributions in binary form must reproduce the above copyright
45: * notice, this list of conditions and the following disclaimer in the
46: * documentation and/or other materials provided with the distribution.
47: * 3. All advertising materials mentioning features or use of this software
48: * must display the following acknowledgements:
49: * This product includes software developed by the University of
50: * California, Berkeley and its contributors.
51: * This product includes software developed at the Information
52: * Technology Division, US Naval Research Laboratory.
53: * 4. Neither the name of the NRL nor the names of its contributors
54: * may be used to endorse or promote products derived from this software
55: * without specific prior written permission.
56: *
57: * THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL AND CONTRIBUTORS ``AS
58: * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
59: * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
60: * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NRL OR
61: * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
62: * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
63: * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
64: * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
65: * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
66: * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
67: * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
68: *
69: * The views and conclusions contained in the software and documentation
70: * are those of the authors and should not be interpreted as representing
71: * official policies, either expressed or implied, of the US Naval
72: * Research Laboratory (NRL).
73: */
74:
75: #include <sys/param.h>
76: #include <sys/systm.h>
77: #include <sys/proc.h>
78: #include <sys/malloc.h>
79: #define MBTYPES
80: #include <sys/mbuf.h>
81: #include <sys/kernel.h>
82: #include <sys/syslog.h>
83: #include <sys/domain.h>
84: #include <sys/protosw.h>
85: #include <sys/pool.h>
86:
87: #include <machine/cpu.h>
88:
89: #include <uvm/uvm_extern.h>
90:
91: struct mbstat mbstat; /* mbuf stats */
92: struct pool mbpool; /* mbuf pool */
93: struct pool mclpool; /* mbuf cluster pool */
94:
95: int max_linkhdr; /* largest link-level header */
96: int max_protohdr; /* largest protocol header */
97: int max_hdr; /* largest link+protocol header */
98: int max_datalen; /* MHLEN - max_hdr */
99:
100: struct mbuf *m_copym0(struct mbuf *, int, int, int, int);
101: void nmbclust_update(void);
102:
103:
104: const char *mclpool_warnmsg =
105: "WARNING: mclpool limit reached; increase kern.maxclusters";
106:
107: /*
108: * Initialize the mbuf allocator.
109: */
110: void
111: mbinit(void)
112: {
113: pool_init(&mbpool, MSIZE, 0, 0, 0, "mbpl", NULL);
114: pool_init(&mclpool, MCLBYTES, 0, 0, 0, "mclpl", NULL);
115:
116: nmbclust_update();
117:
118: /*
119: * Set a low water mark for both mbufs and clusters. This should
120: * help ensure that they can be allocated in a memory starvation
121: * situation. This is important for e.g. diskless systems which
122: * must allocate mbufs in order for the pagedaemon to clean pages.
123: */
124: pool_setlowat(&mbpool, mblowat);
125: pool_setlowat(&mclpool, mcllowat);
126: }
127:
128: void
129: nmbclust_update(void)
130: {
131: /*
132: * Set the hard limit on the mclpool to the number of
133: * mbuf clusters the kernel is to support. Log the limit
134: * reached message max once a minute.
135: */
136: (void)pool_sethardlimit(&mclpool, nmbclust, mclpool_warnmsg, 60);
137: pool_sethiwat(&mbpool, nmbclust);
138: }
139:
140: void
141: m_reclaim(void *arg, int flags)
142: {
143: struct domain *dp;
144: struct protosw *pr;
145: int s = splvm();
146:
147: for (dp = domains; dp; dp = dp->dom_next)
148: for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
149: if (pr->pr_drain)
150: (*pr->pr_drain)();
151: splx(s);
152: mbstat.m_drain++;
153: }
154:
155: /*
156: * Space allocation routines.
157: */
158: struct mbuf *
159: m_get(int nowait, int type)
160: {
161: struct mbuf *m;
162: int s;
163:
164: s = splvm();
165: m = pool_get(&mbpool, nowait == M_WAIT ? PR_WAITOK|PR_LIMITFAIL : 0);
166: if (m) {
167: m->m_type = type;
168: mbstat.m_mtypes[type]++;
169: m->m_next = (struct mbuf *)NULL;
170: m->m_nextpkt = (struct mbuf *)NULL;
171: m->m_data = m->m_dat;
172: m->m_flags = 0;
173: }
174: splx(s);
175: return (m);
176: }
177:
178: struct mbuf *
179: m_gethdr(int nowait, int type)
180: {
181: struct mbuf *m;
182: int s;
183:
184: s = splvm();
185: m = pool_get(&mbpool, nowait == M_WAIT ? PR_WAITOK|PR_LIMITFAIL : 0);
186: if (m) {
187: m->m_type = type;
188: mbstat.m_mtypes[type]++;
189: m->m_next = (struct mbuf *)NULL;
190: m->m_nextpkt = (struct mbuf *)NULL;
191: m->m_data = m->m_pktdat;
192: m->m_flags = M_PKTHDR;
193: m->m_pkthdr.rcvif = NULL;
194: SLIST_INIT(&m->m_pkthdr.tags);
195: m->m_pkthdr.csum_flags = 0;
196: m->m_pkthdr.pf.hdr = NULL;
197: m->m_pkthdr.pf.rtableid = 0;
198: m->m_pkthdr.pf.qid = 0;
199: m->m_pkthdr.pf.tag = 0;
200: m->m_pkthdr.pf.flags = 0;
201: m->m_pkthdr.pf.routed = 0;
202: }
203: splx(s);
204: return (m);
205: }
206:
207: struct mbuf *
208: m_getclr(int nowait, int type)
209: {
210: struct mbuf *m;
211:
212: MGET(m, nowait, type);
213: if (m == NULL)
214: return (NULL);
215: memset(mtod(m, caddr_t), 0, MLEN);
216: return (m);
217: }
218:
219: void
220: m_clget(struct mbuf *m, int how)
221: {
222: int s;
223:
224: s = splvm();
225: m->m_ext.ext_buf =
226: pool_get(&mclpool, how == M_WAIT ? (PR_WAITOK|PR_LIMITFAIL) : 0);
227: splx(s);
228: if (m->m_ext.ext_buf != NULL) {
229: m->m_data = m->m_ext.ext_buf;
230: m->m_flags |= M_EXT|M_CLUSTER;
231: m->m_ext.ext_size = MCLBYTES;
232: m->m_ext.ext_free = NULL;
233: m->m_ext.ext_arg = NULL;
234: MCLINITREFERENCE(m);
235: }
236: }
237:
238: struct mbuf *
239: m_free(struct mbuf *m)
240: {
241: struct mbuf *n;
242: int s;
243:
244: s = splvm();
245: mbstat.m_mtypes[m->m_type]--;
246: if (m->m_flags & M_PKTHDR)
247: m_tag_delete_chain(m);
248: if (m->m_flags & M_EXT) {
249: if (MCLISREFERENCED(m))
250: _MCLDEREFERENCE(m);
251: else if (m->m_flags & M_CLUSTER)
252: pool_put(&mclpool, m->m_ext.ext_buf);
253: else if (m->m_ext.ext_free)
254: (*(m->m_ext.ext_free))(m->m_ext.ext_buf,
255: m->m_ext.ext_size, m->m_ext.ext_arg);
256: else
257: free(m->m_ext.ext_buf,m->m_ext.ext_type);
258: m->m_flags &= ~(M_CLUSTER|M_EXT);
259: m->m_ext.ext_size = 0;
260: }
261: n = m->m_next;
262: pool_put(&mbpool, m);
263: splx(s);
264:
265: return (n);
266: }
267:
268: void
269: m_freem(struct mbuf *m)
270: {
271: struct mbuf *n;
272:
273: if (m == NULL)
274: return;
275: do {
276: MFREE(m, n);
277: } while ((m = n) != NULL);
278: }
279:
280: /*
281: * Mbuffer utility routines.
282: */
283:
284: /*
285: * Lesser-used path for M_PREPEND:
286: * allocate new mbuf to prepend to chain,
287: * copy junk along.
288: */
289: struct mbuf *
290: m_prepend(struct mbuf *m, int len, int how)
291: {
292: struct mbuf *mn;
293:
294: if (len > MHLEN)
295: panic("mbuf prepend length too big");
296:
297: MGET(mn, how, m->m_type);
298: if (mn == NULL) {
299: m_freem(m);
300: return (NULL);
301: }
302: if (m->m_flags & M_PKTHDR)
303: M_MOVE_PKTHDR(mn, m);
304: mn->m_next = m;
305: m = mn;
306: MH_ALIGN(m, len);
307: m->m_len = len;
308: return (m);
309: }
310:
311: /*
312: * Make a copy of an mbuf chain starting "off" bytes from the beginning,
313: * continuing for "len" bytes. If len is M_COPYALL, copy to end of mbuf.
314: * The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller.
315: */
316: int MCFail;
317:
318: struct mbuf *
319: m_copym(struct mbuf *m, int off, int len, int wait)
320: {
321: return m_copym0(m, off, len, wait, 0); /* shallow copy on M_EXT */
322: }
323:
324: /*
325: * m_copym2() is like m_copym(), except it COPIES cluster mbufs, instead
326: * of merely bumping the reference count.
327: */
328: struct mbuf *
329: m_copym2(struct mbuf *m, int off, int len, int wait)
330: {
331: return m_copym0(m, off, len, wait, 1); /* deep copy */
332: }
333:
334: struct mbuf *
335: m_copym0(struct mbuf *m, int off, int len, int wait, int deep)
336: {
337: struct mbuf *n, **np;
338: struct mbuf *top;
339: int copyhdr = 0;
340:
341: if (off < 0 || len < 0)
342: panic("m_copym0: off %d, len %d", off, len);
343: if (off == 0 && m->m_flags & M_PKTHDR)
344: copyhdr = 1;
345: while (off > 0) {
346: if (m == NULL)
347: panic("m_copym0: null mbuf");
348: if (off < m->m_len)
349: break;
350: off -= m->m_len;
351: m = m->m_next;
352: }
353: np = ⊤
354: top = NULL;
355: while (len > 0) {
356: if (m == NULL) {
357: if (len != M_COPYALL)
358: panic("m_copym0: m == NULL and not COPYALL");
359: break;
360: }
361: MGET(n, wait, m->m_type);
362: *np = n;
363: if (n == NULL)
364: goto nospace;
365: if (copyhdr) {
366: M_DUP_PKTHDR(n, m);
367: if (len != M_COPYALL)
368: n->m_pkthdr.len = len;
369: copyhdr = 0;
370: }
371: n->m_len = min(len, m->m_len - off);
372: if (m->m_flags & M_EXT) {
373: if (!deep) {
374: n->m_data = m->m_data + off;
375: n->m_ext = m->m_ext;
376: MCLADDREFERENCE(m, n);
377: } else {
378: /*
379: * we are unsure about the way m was allocated.
380: * copy into multiple MCLBYTES cluster mbufs.
381: */
382: MCLGET(n, wait);
383: n->m_len = 0;
384: n->m_len = M_TRAILINGSPACE(n);
385: n->m_len = min(n->m_len, len);
386: n->m_len = min(n->m_len, m->m_len - off);
387: memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off,
388: (unsigned)n->m_len);
389: }
390: } else
391: memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off,
392: (unsigned)n->m_len);
393: if (len != M_COPYALL)
394: len -= n->m_len;
395: off += n->m_len;
396: #ifdef DIAGNOSTIC
397: if (off > m->m_len)
398: panic("m_copym0 overrun");
399: #endif
400: if (off == m->m_len) {
401: m = m->m_next;
402: off = 0;
403: }
404: np = &n->m_next;
405: }
406: if (top == NULL)
407: MCFail++;
408: return (top);
409: nospace:
410: m_freem(top);
411: MCFail++;
412: return (NULL);
413: }
414:
415: /*
416: * Copy data from an mbuf chain starting "off" bytes from the beginning,
417: * continuing for "len" bytes, into the indicated buffer.
418: */
419: void
420: m_copydata(struct mbuf *m, int off, int len, caddr_t cp)
421: {
422: unsigned count;
423:
424: if (off < 0)
425: panic("m_copydata: off %d < 0", off);
426: if (len < 0)
427: panic("m_copydata: len %d < 0", len);
428: while (off > 0) {
429: if (m == NULL)
430: panic("m_copydata: null mbuf in skip");
431: if (off < m->m_len)
432: break;
433: off -= m->m_len;
434: m = m->m_next;
435: }
436: while (len > 0) {
437: if (m == NULL)
438: panic("m_copydata: null mbuf");
439: count = min(m->m_len - off, len);
440: bcopy(mtod(m, caddr_t) + off, cp, count);
441: len -= count;
442: cp += count;
443: off = 0;
444: m = m->m_next;
445: }
446: }
447:
448: /*
449: * Copy data from a buffer back into the indicated mbuf chain,
450: * starting "off" bytes from the beginning, extending the mbuf
451: * chain if necessary. The mbuf needs to be properly initialized
452: * including the setting of m_len.
453: */
454: void
455: m_copyback(struct mbuf *m0, int off, int len, const void *_cp)
456: {
457: int mlen;
458: struct mbuf *m = m0, *n;
459: int totlen = 0;
460: caddr_t cp = (caddr_t)_cp;
461:
462: if (m0 == NULL)
463: return;
464: while (off > (mlen = m->m_len)) {
465: off -= mlen;
466: totlen += mlen;
467: if (m->m_next == NULL) {
468: n = m_getclr(M_DONTWAIT, m->m_type);
469: if (n == NULL)
470: goto out;
471: n->m_len = min(MLEN, len + off);
472: m->m_next = n;
473: }
474: m = m->m_next;
475: }
476: while (len > 0) {
477: mlen = min (m->m_len - off, len);
478: bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen);
479: cp += mlen;
480: len -= mlen;
481: mlen += off;
482: off = 0;
483: totlen += mlen;
484: if (len == 0)
485: break;
486: if (m->m_next == NULL) {
487: n = m_get(M_DONTWAIT, m->m_type);
488: if (n == NULL)
489: break;
490: n->m_len = min(MLEN, len);
491: m->m_next = n;
492: }
493: m = m->m_next;
494: }
495: out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
496: m->m_pkthdr.len = totlen;
497: }
498:
499: /*
500: * Concatenate mbuf chain n to m.
501: * n might be copied into m (when n->m_len is small), therefore data portion of
502: * n could be copied into an mbuf of different mbuf type.
503: * Therefore both chains should be of the same type (e.g. MT_DATA).
504: * Any m_pkthdr is not updated.
505: */
506: void
507: m_cat(struct mbuf *m, struct mbuf *n)
508: {
509: while (m->m_next)
510: m = m->m_next;
511: while (n) {
512: if (M_READONLY(m) || n->m_len > M_TRAILINGSPACE(m)) {
513: /* just join the two chains */
514: m->m_next = n;
515: return;
516: }
517: /* splat the data from one into the other */
518: bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
519: (u_int)n->m_len);
520: m->m_len += n->m_len;
521: n = m_free(n);
522: }
523: }
524:
525: void
526: m_adj(struct mbuf *mp, int req_len)
527: {
528: int len = req_len;
529: struct mbuf *m;
530: int count;
531:
532: if ((m = mp) == NULL)
533: return;
534: if (len >= 0) {
535: /*
536: * Trim from head.
537: */
538: while (m != NULL && len > 0) {
539: if (m->m_len <= len) {
540: len -= m->m_len;
541: m->m_len = 0;
542: m = m->m_next;
543: } else {
544: m->m_len -= len;
545: m->m_data += len;
546: len = 0;
547: }
548: }
549: m = mp;
550: if (mp->m_flags & M_PKTHDR)
551: m->m_pkthdr.len -= (req_len - len);
552: } else {
553: /*
554: * Trim from tail. Scan the mbuf chain,
555: * calculating its length and finding the last mbuf.
556: * If the adjustment only affects this mbuf, then just
557: * adjust and return. Otherwise, rescan and truncate
558: * after the remaining size.
559: */
560: len = -len;
561: count = 0;
562: for (;;) {
563: count += m->m_len;
564: if (m->m_next == NULL)
565: break;
566: m = m->m_next;
567: }
568: if (m->m_len >= len) {
569: m->m_len -= len;
570: if (mp->m_flags & M_PKTHDR)
571: mp->m_pkthdr.len -= len;
572: return;
573: }
574: count -= len;
575: if (count < 0)
576: count = 0;
577: /*
578: * Correct length for chain is "count".
579: * Find the mbuf with last data, adjust its length,
580: * and toss data from remaining mbufs on chain.
581: */
582: m = mp;
583: if (m->m_flags & M_PKTHDR)
584: m->m_pkthdr.len = count;
585: for (; m; m = m->m_next) {
586: if (m->m_len >= count) {
587: m->m_len = count;
588: break;
589: }
590: count -= m->m_len;
591: }
592: while ((m = m->m_next) != NULL)
593: m->m_len = 0;
594: }
595: }
596:
597: /*
598: * Rearange an mbuf chain so that len bytes are contiguous
599: * and in the data area of an mbuf (so that mtod and dtom
600: * will work for a structure of size len). Returns the resulting
601: * mbuf chain on success, frees it and returns null on failure.
602: * If there is room, it will add up to max_protohdr-len extra bytes to the
603: * contiguous region in an attempt to avoid being called next time.
604: */
605: int MPFail;
606:
607: struct mbuf *
608: m_pullup(struct mbuf *n, int len)
609: {
610: struct mbuf *m;
611: int count;
612: int space;
613:
614: /*
615: * If first mbuf has no cluster, and has room for len bytes
616: * without shifting current data, pullup into it,
617: * otherwise allocate a new mbuf to prepend to the chain.
618: */
619: if ((n->m_flags & M_EXT) == 0 &&
620: n->m_data + len < &n->m_dat[MLEN] && n->m_next) {
621: if (n->m_len >= len)
622: return (n);
623: m = n;
624: n = n->m_next;
625: len -= m->m_len;
626: } else {
627: if (len > MHLEN)
628: goto bad;
629: MGET(m, M_DONTWAIT, n->m_type);
630: if (m == NULL)
631: goto bad;
632: m->m_len = 0;
633: if (n->m_flags & M_PKTHDR)
634: M_MOVE_PKTHDR(m, n);
635: }
636: space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
637: do {
638: count = min(min(max(len, max_protohdr), space), n->m_len);
639: bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
640: (unsigned)count);
641: len -= count;
642: m->m_len += count;
643: n->m_len -= count;
644: space -= count;
645: if (n->m_len)
646: n->m_data += count;
647: else
648: n = m_free(n);
649: } while (len > 0 && n);
650: if (len > 0) {
651: (void)m_free(m);
652: goto bad;
653: }
654: m->m_next = n;
655: return (m);
656: bad:
657: m_freem(n);
658: MPFail++;
659: return (NULL);
660: }
661:
662: /*
663: * m_pullup2() works like m_pullup, save that len can be <= MCLBYTES.
664: * m_pullup2() only works on values of len such that MHLEN < len <= MCLBYTES,
665: * it calls m_pullup() for values <= MHLEN. It also only coagulates the
666: * reqested number of bytes. (For those of us who expect unwieldly option
667: * headers.
668: *
669: * KEBE SAYS: Remember that dtom() calls with data in clusters does not work!
670: */
671: struct mbuf *
672: m_pullup2(struct mbuf *n, int len)
673: {
674: struct mbuf *m;
675: int count;
676:
677: if (len <= MHLEN)
678: return m_pullup(n, len);
679: if ((n->m_flags & M_EXT) != 0 &&
680: n->m_data + len < &n->m_data[MCLBYTES] && n->m_next) {
681: if (n->m_len >= len)
682: return (n);
683: m = n;
684: n = n->m_next;
685: len -= m->m_len;
686: } else {
687: if (len > MCLBYTES)
688: goto bad;
689: MGET(m, M_DONTWAIT, n->m_type);
690: if (m == NULL)
691: goto bad;
692: MCLGET(m, M_DONTWAIT);
693: if ((m->m_flags & M_EXT) == 0)
694: goto bad;
695: m->m_len = 0;
696: if (n->m_flags & M_PKTHDR) {
697: /* Too many adverse side effects. */
698: /* M_MOVE_PKTHDR(m, n); */
699: m->m_flags = (n->m_flags & M_COPYFLAGS) |
700: M_EXT | M_CLUSTER;
701: M_MOVE_HDR(m, n);
702: /* n->m_data is cool. */
703: }
704: }
705:
706: do {
707: count = min(len, n->m_len);
708: bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
709: (unsigned)count);
710: len -= count;
711: m->m_len += count;
712: n->m_len -= count;
713: if (n->m_len)
714: n->m_data += count;
715: else
716: n = m_free(n);
717: } while (len > 0 && n);
718: if (len > 0) {
719: (void)m_free(m);
720: goto bad;
721: }
722: m->m_next = n;
723:
724: return (m);
725: bad:
726: m_freem(n);
727: MPFail++;
728: return (NULL);
729: }
730:
731: /*
732: * Return a pointer to mbuf/offset of location in mbuf chain.
733: */
734: struct mbuf *
735: m_getptr(struct mbuf *m, int loc, int *off)
736: {
737: while (loc >= 0) {
738: /* Normal end of search */
739: if (m->m_len > loc) {
740: *off = loc;
741: return (m);
742: }
743: else {
744: loc -= m->m_len;
745:
746: if (m->m_next == NULL) {
747: if (loc == 0) {
748: /* Point at the end of valid data */
749: *off = m->m_len;
750: return (m);
751: }
752: else
753: return (NULL);
754: } else
755: m = m->m_next;
756: }
757: }
758:
759: return (NULL);
760: }
761:
762: /*
763: * Inject a new mbuf chain of length siz in mbuf chain m0 at
764: * position len0. Returns a pointer to the first injected mbuf, or
765: * NULL on failure (m0 is left undisturbed). Note that if there is
766: * enough space for an object of size siz in the appropriate position,
767: * no memory will be allocated. Also, there will be no data movement in
768: * the first len0 bytes (pointers to that will remain valid).
769: *
770: * XXX It is assumed that siz is less than the size of an mbuf at the moment.
771: */
772: struct mbuf *
773: m_inject(struct mbuf *m0, int len0, int siz, int wait)
774: {
775: struct mbuf *m, *n, *n2 = NULL, *n3;
776: unsigned len = len0, remain;
777:
778: if ((siz >= MHLEN) || (len0 <= 0))
779: return (NULL);
780: for (m = m0; m && len > m->m_len; m = m->m_next)
781: len -= m->m_len;
782: if (m == NULL)
783: return (NULL);
784: remain = m->m_len - len;
785: if (remain == 0) {
786: if ((m->m_next) && (M_LEADINGSPACE(m->m_next) >= siz)) {
787: m->m_next->m_len += siz;
788: if (m0->m_flags & M_PKTHDR)
789: m0->m_pkthdr.len += siz;
790: m->m_next->m_data -= siz;
791: return m->m_next;
792: }
793: } else {
794: n2 = m_copym2(m, len, remain, wait);
795: if (n2 == NULL)
796: return (NULL);
797: }
798:
799: MGET(n, wait, MT_DATA);
800: if (n == NULL) {
801: if (n2)
802: m_freem(n2);
803: return (NULL);
804: }
805:
806: n->m_len = siz;
807: if (m0->m_flags & M_PKTHDR)
808: m0->m_pkthdr.len += siz;
809: m->m_len -= remain; /* Trim */
810: if (n2) {
811: for (n3 = n; n3->m_next != NULL; n3 = n3->m_next)
812: ;
813: n3->m_next = n2;
814: } else
815: n3 = n;
816: for (; n3->m_next != NULL; n3 = n3->m_next)
817: ;
818: n3->m_next = m->m_next;
819: m->m_next = n;
820: return n;
821: }
822:
823: /*
824: * Partition an mbuf chain in two pieces, returning the tail --
825: * all but the first len0 bytes. In case of failure, it returns NULL and
826: * attempts to restore the chain to its original state.
827: */
828: struct mbuf *
829: m_split(struct mbuf *m0, int len0, int wait)
830: {
831: struct mbuf *m, *n;
832: unsigned len = len0, remain, olen;
833:
834: for (m = m0; m && len > m->m_len; m = m->m_next)
835: len -= m->m_len;
836: if (m == NULL)
837: return (NULL);
838: remain = m->m_len - len;
839: if (m0->m_flags & M_PKTHDR) {
840: MGETHDR(n, wait, m0->m_type);
841: if (n == NULL)
842: return (NULL);
843: M_DUP_PKTHDR(n, m0);
844: n->m_pkthdr.len -= len0;
845: olen = m0->m_pkthdr.len;
846: m0->m_pkthdr.len = len0;
847: if (m->m_flags & M_EXT)
848: goto extpacket;
849: if (remain > MHLEN) {
850: /* m can't be the lead packet */
851: MH_ALIGN(n, 0);
852: n->m_next = m_split(m, len, wait);
853: if (n->m_next == NULL) {
854: (void) m_free(n);
855: m0->m_pkthdr.len = olen;
856: return (NULL);
857: } else
858: return (n);
859: } else
860: MH_ALIGN(n, remain);
861: } else if (remain == 0) {
862: n = m->m_next;
863: m->m_next = NULL;
864: return (n);
865: } else {
866: MGET(n, wait, m->m_type);
867: if (n == NULL)
868: return (NULL);
869: M_ALIGN(n, remain);
870: }
871: extpacket:
872: if (m->m_flags & M_EXT) {
873: n->m_ext = m->m_ext;
874: MCLADDREFERENCE(m, n);
875: n->m_data = m->m_data + len;
876: } else {
877: bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain);
878: }
879: n->m_len = remain;
880: m->m_len = len;
881: n->m_next = m->m_next;
882: m->m_next = NULL;
883: return (n);
884: }
885:
886: /*
887: * Routine to copy from device local memory into mbufs.
888: */
889: struct mbuf *
890: m_devget(char *buf, int totlen, int off, struct ifnet *ifp,
891: void (*copy)(const void *, void *, size_t))
892: {
893: struct mbuf *m;
894: struct mbuf *top = NULL, **mp = ⊤
895: int len;
896: char *cp;
897: char *epkt;
898:
899: cp = buf;
900: epkt = cp + totlen;
901: if (off) {
902: /*
903: * If 'off' is non-zero, packet is trailer-encapsulated,
904: * so we have to skip the type and length fields.
905: */
906: cp += off + 2 * sizeof(u_int16_t);
907: totlen -= 2 * sizeof(u_int16_t);
908: }
909: MGETHDR(m, M_DONTWAIT, MT_DATA);
910: if (m == NULL)
911: return (NULL);
912: m->m_pkthdr.rcvif = ifp;
913: m->m_pkthdr.len = totlen;
914: m->m_len = MHLEN;
915:
916: while (totlen > 0) {
917: if (top != NULL) {
918: MGET(m, M_DONTWAIT, MT_DATA);
919: if (m == NULL) {
920: m_freem(top);
921: return (NULL);
922: }
923: m->m_len = MLEN;
924: }
925: len = min(totlen, epkt - cp);
926: if (len >= MINCLSIZE) {
927: MCLGET(m, M_DONTWAIT);
928: if (m->m_flags & M_EXT)
929: m->m_len = len = min(len, MCLBYTES);
930: else
931: len = m->m_len;
932: } else {
933: /*
934: * Place initial small packet/header at end of mbuf.
935: */
936: if (len < m->m_len) {
937: if (top == NULL &&
938: len + max_linkhdr <= m->m_len)
939: m->m_data += max_linkhdr;
940: m->m_len = len;
941: } else
942: len = m->m_len;
943: }
944: if (copy)
945: copy(cp, mtod(m, caddr_t), (size_t)len);
946: else
947: bcopy(cp, mtod(m, caddr_t), (size_t)len);
948: cp += len;
949: *mp = m;
950: mp = &m->m_next;
951: totlen -= len;
952: if (cp == epkt)
953: cp = buf;
954: }
955: return (top);
956: }
957:
958: void
959: m_zero(struct mbuf *m)
960: {
961: while (m) {
962: #ifdef DIAGNOSTIC
963: if (M_READONLY(m))
964: panic("m_zero: M_READONLY");
965: #endif /* DIAGNOSTIC */
966: if (m->m_flags & M_EXT)
967: memset(m->m_ext.ext_buf, 0, m->m_ext.ext_size);
968: else {
969: if (m->m_flags & M_PKTHDR)
970: memset(m->m_pktdat, 0, MHLEN);
971: else
972: memset(m->m_dat, 0, MLEN);
973: }
974: m = m->m_next;
975: }
976: }
977:
978: /*
979: * Apply function f to the data in an mbuf chain starting "off" bytes from the
980: * beginning, continuing for "len" bytes.
981: */
982: int
983: m_apply(struct mbuf *m, int off, int len,
984: int (*f)(caddr_t, caddr_t, unsigned int), caddr_t fstate)
985: {
986: int rval;
987: unsigned int count;
988:
989: if (len < 0)
990: panic("m_apply: len %d < 0", len);
991: if (off < 0)
992: panic("m_apply: off %d < 0", off);
993: while (off > 0) {
994: if (m == NULL)
995: panic("m_apply: null mbuf in skip");
996: if (off < m->m_len)
997: break;
998: off -= m->m_len;
999: m = m->m_next;
1000: }
1001: while (len > 0) {
1002: if (m == NULL)
1003: panic("m_apply: null mbuf");
1004: count = min(m->m_len - off, len);
1005:
1006: rval = f(fstate, mtod(m, caddr_t) + off, count);
1007: if (rval)
1008: return (rval);
1009:
1010: len -= count;
1011: off = 0;
1012: m = m->m_next;
1013: }
1014:
1015: return (0);
1016: }