Annotation of libaitio/src/bpf.c, revision 1.4
1.2 misho 1: /*************************************************************************
2: * (C) 2013 AITNET ltd - Sofia/Bulgaria - <misho@aitnet.org>
3: * by Michael Pounov <misho@elwix.org>
4: *
5: * $Author: misho $
1.4 ! misho 6: * $Id: bpf.c,v 1.3.8.4 2013/10/21 16:30:28 misho Exp $
1.2 misho 7: *
8: **************************************************************************
9: The ELWIX and AITNET software is distributed under the following
10: terms:
11:
12: All of the documentation and software included in the ELWIX and AITNET
13: Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>
14:
15: Copyright 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
16: by Michael Pounov <misho@elwix.org>. All rights reserved.
17:
18: Redistribution and use in source and binary forms, with or without
19: modification, are permitted provided that the following conditions
20: are met:
21: 1. Redistributions of source code must retain the above copyright
22: notice, this list of conditions and the following disclaimer.
23: 2. Redistributions in binary form must reproduce the above copyright
24: notice, this list of conditions and the following disclaimer in the
25: documentation and/or other materials provided with the distribution.
26: 3. All advertising materials mentioning features or use of this software
27: must display the following acknowledgement:
28: This product includes software developed by Michael Pounov <misho@elwix.org>
29: ELWIX - Embedded LightWeight unIX and its contributors.
30: 4. Neither the name of AITNET nor the names of its contributors
31: may be used to endorse or promote products derived from this software
32: without specific prior written permission.
33:
34: THIS SOFTWARE IS PROVIDED BY AITNET AND CONTRIBUTORS ``AS IS'' AND
35: ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
36: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
37: ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
38: FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
39: DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
40: OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
41: HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
42: LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
43: OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
44: SUCH DAMAGE.
45: */
46: #include "global.h"
47:
48:
49: /*
50: * io_get1stiface() - Get first interface of host
51: *
52: * @szIface = interface string buffer
53: * @iflen = size of interface buffer
54: * return: -1 error or 0 ok
55: */
56: int
57: io_get1stiface(char *szIface, int iflen)
58: {
59: struct ifaddrs *ifa;
60:
61: if (!szIface || !iflen)
62: return -1;
63:
64: getifaddrs(&ifa);
65: strlcpy(szIface, ifa->ifa_name, iflen);
66: freeifaddrs(ifa);
67: return 0;
68: }
69:
70: /*
71: * io_etherClose() - Close BPF interface
72: *
73: * @eth = bpf handle
74: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
75: * return: none
76: */
77: void
78: io_etherClose(int eth, void **zcbuf)
79: {
80: #ifdef __FreeBSD__
81: struct bpf_zbuf *zbuf = NULL;
82: #endif
83:
84: if (eth > STDERR_FILENO)
85: close(eth);
86:
87: if (zcbuf && *zcbuf) {
88: #ifdef __FreeBSD__
89: zbuf = *zcbuf;
90: munmap(zbuf->bz_bufb, zbuf->bz_buflen);
91: munmap(zbuf->bz_bufa, zbuf->bz_buflen);
92: e_free(*zcbuf);
93: *zcbuf = NULL;
94: #endif
95: }
96: }
97:
98: #ifdef __FreeBSD__
99: static inline struct bpf_zbuf *
100: allocZCbuf(u_int len)
101: {
102: struct bpf_zbuf *zbuf = NULL;
103:
104: zbuf = e_malloc(sizeof(struct bpf_zbuf));
105: if (!zbuf) {
106: io_SetErr(elwix_GetErrno(), "%s", elwix_GetError());
107: return NULL;
108: } else
109: memset(zbuf, 0, sizeof(struct bpf_zbuf));
110:
111: zbuf->bz_buflen = roundup(len, getpagesize());
112: zbuf->bz_bufa = mmap(NULL, zbuf->bz_buflen, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
113: if (zbuf->bz_bufa == MAP_FAILED) {
114: LOGERR;
115: e_free(zbuf);
116: return NULL;
117: } else
118: memset(zbuf->bz_bufa, 0, zbuf->bz_buflen);
119: zbuf->bz_bufb = mmap(NULL, zbuf->bz_buflen, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
120: if (zbuf->bz_bufb == MAP_FAILED) {
121: LOGERR;
122: munmap(zbuf->bz_bufa, zbuf->bz_buflen);
123: e_free(zbuf);
124: return NULL;
125: } else
126: memset(zbuf->bz_bufb, 0, zbuf->bz_buflen);
127:
128: return zbuf;
129: }
130: #endif
131:
132: /*
133: * io_etherOpen() - Open BPF interface to device
134: *
135: * @csIface = interface name
136: * @flags = open flags
137: * @whdr = with complete headers
1.3 misho 138: * @wdlt = with data link type
1.2 misho 139: * @buflen = buffer length
140: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
141: * return: -1 error or >-1 bpf handle
142: */
143: int
1.3 misho 144: io_etherOpen(const char *csIface, int flags, int whdr, int wdlt,
145: u_int *buflen, void **zcbuf)
1.2 misho 146: {
147: int eth = -1;
148: register int i;
149: char szStr[STRSIZ];
150: struct ifreq ifr;
151: u_int n = 1;
152:
153: #ifndef __FreeBSD__
154: if (zcbuf) {
155: io_SetErr(ENOTSUP, "bpf zero copy buffer mode is not supported");
156: return -1;
157: }
158: #endif
159:
160: for (i = 0; i < BPF_DEV_MAX; i++) {
161: memset(szStr, 0, sizeof szStr);
162: snprintf(szStr, sizeof szStr, "/dev/bpf%d", i);
163: eth = open(szStr, flags);
164: if (eth > STDERR_FILENO)
165: break;
166: }
167: if (eth < 3) {
168: LOGERR;
169: return -1;
170: }
171:
1.4 ! misho 172: if (csIface)
! 173: strlcpy(szStr, csIface, sizeof szStr);
! 174: else if (io_get1stiface(szStr, sizeof szStr) == -1) {
! 175: close(eth);
! 176: return -1;
! 177: }
! 178:
! 179: n = 1;
! 180: if (whdr && ioctl(eth, BIOCSHDRCMPLT, &n) == -1) {
! 181: LOGERR;
! 182: close(eth);
! 183: return -1;
! 184: }
! 185: if (wdlt && ioctl(eth, BIOCSDLT, &wdlt) == -1) {
! 186: LOGERR;
! 187: close(eth);
! 188: return -1;
! 189: }
! 190: if (ioctl(eth, BIOCIMMEDIATE, &n) == -1) {
! 191: LOGERR;
! 192: close(eth);
! 193: return -1;
! 194: }
! 195:
1.2 misho 196: if (!zcbuf) {
197: if (ioctl(eth, BIOCGBLEN, &n) == -1) {
198: LOGERR;
199: close(eth);
200: return -1;
201: } else
1.4 ! misho 202: n = (buflen && *buflen) ? *buflen : getpagesize();
! 203:
1.2 misho 204: if (ioctl(eth, BIOCSBLEN, &n) == -1) {
205: LOGERR;
206: close(eth);
207: return -1;
208: }
1.4 ! misho 209: if (buflen)
1.2 misho 210: *buflen = n;
211: } else {
212: #ifdef __FreeBSD__
213: n = BPF_BUFMODE_ZBUF;
214: if (ioctl(eth, BIOCSETBUFMODE, &n) == -1) {
215: LOGERR;
216: close(eth);
217: return -1;
218: }
219: if (ioctl(eth, BIOCGETZMAX, &n) == -1) {
220: LOGERR;
221: close(eth);
222: return -1;
223: } else
224: n = (buflen && *buflen) ? *buflen : n;
225: if (!(*zcbuf = allocZCbuf(n))) {
226: close(eth);
227: return -1;
228: }
229: if (ioctl(eth, BIOCSETZBUF, *zcbuf) == -1) {
230: LOGERR;
231: io_etherClose(eth, zcbuf);
232: return -1;
233: }
234: if (buflen && *buflen)
235: *buflen = n;
236: #endif
237: }
238:
239: memset(&ifr, 0, sizeof ifr);
240: strlcpy(ifr.ifr_name, szStr, sizeof ifr.ifr_name);
241: if (ioctl(eth, BIOCSETIF, &ifr) == -1) {
242: LOGERR;
243: io_etherClose(eth, zcbuf);
244: return -1;
245: }
246:
247: return eth;
248: }
249:
250: /*
251: * io_etherSend() - Send packet to bpf
252: *
253: * @eth = bpf handle
254: * @buf = buffer
255: * @buflen = buffer length
256: * return: -1 error or !=-1 written bytes
257: */
258: ssize_t
259: io_etherSend(int eth, const void *buf, size_t buflen)
260: {
261: ssize_t wlen = 0;
262:
263: if (!buf || !buflen) {
264: io_SetErr(EINVAL, "invalid arguments");
265: return -1;
266: }
267:
268: wlen = write(eth, buf, buflen);
269: if (wlen == -1)
270: LOGERR;
271: return wlen;
272: }
273:
274: #ifdef __FreeBSD__
275: static inline void
276: ackZCbuf(struct bpf_zbuf_header *bzh)
277: {
278: atomic_store_rel_int(&bzh->bzh_user_gen, bzh->bzh_kernel_gen);
279: }
280:
281: static inline int
282: chkZCbuf(struct bpf_zbuf_header *bzh)
283: {
284: /* return true if userspace owns buffer, and false otherwise. */
285: return (bzh->bzh_user_gen != atomic_load_acq_int(&bzh->bzh_kernel_gen));
286: }
287:
288: static ssize_t
289: nextZCbuf(int eth, struct bpf_zbuf * __restrict zbuf, void * __restrict buf, size_t buflen)
290: {
291: ssize_t rlen = 0;
292: struct bpf_zbuf bz;
293: struct bpf_zbuf_header *bzh;
294: off_t pos = 0;
295:
296: bzh = (struct bpf_zbuf_header *) zbuf->bz_bufa;
297: if (chkZCbuf(bzh)) {
298: rlen = MIN(atomic_load_acq_int(&bzh->bzh_kernel_len), buflen);
299: memcpy(buf + pos, zbuf->bz_bufa + sizeof(struct bpf_zbuf_header), rlen);
300: ackZCbuf(bzh);
301: pos += rlen;
302: }
303: bzh = (struct bpf_zbuf_header *) zbuf->bz_bufb;
304: if (chkZCbuf(bzh)) {
305: rlen = MIN(atomic_load_acq_int(&bzh->bzh_kernel_len), buflen);
306: memcpy(buf + pos, zbuf->bz_bufb + sizeof(struct bpf_zbuf_header), rlen);
307: ackZCbuf(bzh);
308: pos += rlen;
309: }
310:
311: if (!pos) {
312: if ((rlen = ioctl(eth, BIOCROTZBUF, &bz)) == -1)
313: LOGERR;
314: } else
315: rlen = pos;
316: return rlen;
317: }
318: #endif
319:
320: /*
321: * io_etherRecv() - Receive packet from bpf
322: *
323: * @eth = bpf handle
324: * @buf = buffer
325: * @buflen = buffer length
326: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
327: * return: -1 error or !=-1 readed bytes
328: */
329: ssize_t
330: io_etherRecv(int eth, void * __restrict buf, size_t buflen, void * __restrict zcbuf)
331: {
332: ssize_t rlen = 0;
1.3 misho 333: struct bpf_hdr *h;
1.2 misho 334:
335: if (!buf || !buflen) {
336: io_SetErr(EINVAL, "invalid arguments");
337: return -1;
338: }
339:
340: if (!zcbuf) {
341: rlen = read(eth, buf, buflen);
1.4 ! misho 342: if (rlen == -1) {
1.2 misho 343: LOGERR;
1.4 ! misho 344: return -1;
! 345: }
1.2 misho 346: } else {
347: #ifdef __FreeBSD__
348: rlen = nextZCbuf(eth, (struct bpf_zbuf*) zcbuf, buf, buflen);
349: if (!rlen)
350: rlen = nextZCbuf(eth, (struct bpf_zbuf*) zcbuf, buf, buflen);
351: #else
352: rlen = -1;
353: io_SetErr(ENOTSUP, "bpf zero copy buffer mode is not supported");
354: #endif
355: }
356:
1.3 misho 357: h = (struct bpf_hdr*) buf;
358: rlen -= h->bh_hdrlen;
359:
360: if (h->bh_caplen != rlen) {
361: if (h->bh_caplen < rlen)
362: rlen = h->bh_caplen;
363: else {
364: io_SetErr(EIO, "Captured %d bytes should be at most %d bytes",
365: h->bh_caplen, rlen);
366: return -1;
367: }
368: }
369:
370: memmove(buf, buf + h->bh_hdrlen, rlen);
1.2 misho 371: return rlen;
372: }
1.4 ! misho 373:
! 374: /*
! 375: * io_etherFilter() - BPF filter routine
! 376: *
! 377: * @eth = bpf handle
! 378: * @io = filter direction
! 379: * (IO_ETHER_FILTER_PROMISC|IO_ETHER_FILTER_NOTREAD|IO_ETHER_FILTER_READ|IO_ETHER_FILTER_WRITE)
! 380: * @insn = BPF filter instruction array
! 381: * @insnlen = Length of BPF filter instruction array
! 382: * return: -1 error or 0 ok
! 383: */
! 384: int
! 385: io_etherFilter(int eth, int io, struct bpf_insn * __restrict insn, size_t insnlen)
! 386: {
! 387: int ret = 0;
! 388: struct bpf_program fcode = { 0 };
! 389:
! 390: if (io != IO_ETHER_FILTER_PROMISC && (!insn || !insnlen)) {
! 391: io_SetErr(EINVAL, "invalid arguments");
! 392: return -1;
! 393: }
! 394:
! 395: switch (io) {
! 396: case IO_ETHER_FILTER_PROMISC: /* promiscuous mode */
! 397: ret = ioctl(eth, BIOCPROMISC, NULL);
! 398: break;
! 399: case IO_ETHER_FILTER_NOTREAD: /* read not filter */
! 400: fcode.bf_len = insnlen / sizeof(struct bpf_insn);
! 401: fcode.bf_insns = insn;
! 402: ret = ioctl(eth, BIOCSETFNR, &fcode);
! 403: break;
! 404: case IO_ETHER_FILTER_READ: /* read filter */
! 405: fcode.bf_len = insnlen / sizeof(struct bpf_insn);
! 406: fcode.bf_insns = insn;
! 407: ret = ioctl(eth, BIOCSETF, &fcode);
! 408: break;
! 409: case IO_ETHER_FILTER_WRITE: /* write filter */
! 410: fcode.bf_len = insnlen / sizeof(struct bpf_insn);
! 411: fcode.bf_insns = insn;
! 412: ret = ioctl(eth, BIOCSETWF, &fcode);
! 413: break;
! 414: }
! 415:
! 416: if (ret == -1)
! 417: LOGERR;
! 418: return ret;
! 419: }
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