1: /*************************************************************************
2: * (C) 2013 AITNET ltd - Sofia/Bulgaria - <misho@aitnet.org>
3: * by Michael Pounov <misho@elwix.org>
4: *
5: * $Author: misho $
6: * $Id: bpf.c,v 1.4.16.1 2013/12/04 10:08:41 misho Exp $
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_getmaciface() - Get MAC address from interface name
72: *
73: * @csIface = interface name
74: * @ea = ethernet address
75: * return: -1 error, 0 ok or 1 not found
76: */
77: int
78: io_getmaciface(const char *csIface, ether_addr_t * __restrict ea)
79: {
80: struct ifaddrs *ifa, *ifp;
81: struct sockaddr_dl *dl;
82: int ret = 1;
83:
84: if (!csIface || !ea)
85: return -1;
86: else
87: memset(ea, 0, sizeof(ether_addr_t));
88:
89: getifaddrs(&ifa);
90: for (ifp = ifa; ifp; ifp = ifp->ifa_next)
91: if (!strcmp(csIface, ifp->ifa_name) && ifp->ifa_addr &&
92: ifp->ifa_addr->sa_family == AF_LINK) {
93: dl = (struct sockaddr_dl*) ifp->ifa_addr;
94: if ((dl->sdl_type == IFT_ETHER || dl->sdl_type == IFT_L2VLAN ||
95: dl->sdl_type == IFT_BRIDGE) &&
96: dl->sdl_alen == ETHER_ADDR_LEN) {
97: memcpy(ea, LLADDR(dl), sizeof(ether_addr_t));
98: ret = 0;
99: break;
100: }
101: }
102: freeifaddrs(ifa);
103:
104: return ret;
105: }
106:
107: /*
108: * io_etherClose() - Close BPF interface
109: *
110: * @eth = bpf handle
111: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
112: * return: none
113: */
114: void
115: io_etherClose(int eth, void **zcbuf)
116: {
117: #ifdef __FreeBSD__
118: struct bpf_zbuf *zbuf = NULL;
119: #endif
120:
121: if (eth > STDERR_FILENO)
122: close(eth);
123:
124: if (zcbuf && *zcbuf) {
125: #ifdef __FreeBSD__
126: zbuf = *zcbuf;
127: munmap(zbuf->bz_bufb, zbuf->bz_buflen);
128: munmap(zbuf->bz_bufa, zbuf->bz_buflen);
129: e_free(*zcbuf);
130: *zcbuf = NULL;
131: #endif
132: }
133: }
134:
135: #ifdef __FreeBSD__
136: static inline struct bpf_zbuf *
137: allocZCbuf(u_int len)
138: {
139: struct bpf_zbuf *zbuf = NULL;
140:
141: zbuf = e_malloc(sizeof(struct bpf_zbuf));
142: if (!zbuf) {
143: io_SetErr(elwix_GetErrno(), "%s", elwix_GetError());
144: return NULL;
145: } else
146: memset(zbuf, 0, sizeof(struct bpf_zbuf));
147:
148: zbuf->bz_buflen = roundup(len, getpagesize());
149: zbuf->bz_bufa = mmap(NULL, zbuf->bz_buflen, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
150: if (zbuf->bz_bufa == MAP_FAILED) {
151: LOGERR;
152: e_free(zbuf);
153: return NULL;
154: } else
155: memset(zbuf->bz_bufa, 0, zbuf->bz_buflen);
156: zbuf->bz_bufb = mmap(NULL, zbuf->bz_buflen, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
157: if (zbuf->bz_bufb == MAP_FAILED) {
158: LOGERR;
159: munmap(zbuf->bz_bufa, zbuf->bz_buflen);
160: e_free(zbuf);
161: return NULL;
162: } else
163: memset(zbuf->bz_bufb, 0, zbuf->bz_buflen);
164:
165: return zbuf;
166: }
167: #endif
168:
169: /*
170: * io_etherOpen() - Open BPF interface to device
171: *
172: * @csIface = interface name
173: * @flags = open flags
174: * @whdr = with complete headers
175: * @wdlt = with data link type
176: * @buflen = buffer length
177: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
178: * return: -1 error or >-1 bpf handle
179: */
180: int
181: io_etherOpen(const char *csIface, int flags, int whdr, int wdlt,
182: u_int *buflen, void **zcbuf)
183: {
184: int eth = -1;
185: register int i;
186: char szStr[STRSIZ];
187: struct ifreq ifr;
188: u_int n = 1;
189:
190: #ifndef __FreeBSD__
191: if (zcbuf) {
192: io_SetErr(ENOTSUP, "bpf zero copy buffer mode is not supported");
193: return -1;
194: }
195: #endif
196:
197: for (i = 0; i < BPF_DEV_MAX; i++) {
198: memset(szStr, 0, sizeof szStr);
199: snprintf(szStr, sizeof szStr, "/dev/bpf%d", i);
200: eth = open(szStr, flags);
201: if (eth > STDERR_FILENO)
202: break;
203: }
204: if (eth < 3) {
205: LOGERR;
206: return -1;
207: }
208:
209: if (csIface)
210: strlcpy(szStr, csIface, sizeof szStr);
211: else if (io_get1stiface(szStr, sizeof szStr) == -1) {
212: close(eth);
213: return -1;
214: }
215:
216: n = 1;
217: if (whdr && ioctl(eth, BIOCSHDRCMPLT, &n) == -1) {
218: LOGERR;
219: close(eth);
220: return -1;
221: }
222: if (wdlt && ioctl(eth, BIOCSDLT, &wdlt) == -1) {
223: LOGERR;
224: close(eth);
225: return -1;
226: }
227: if (ioctl(eth, BIOCIMMEDIATE, &n) == -1) {
228: LOGERR;
229: close(eth);
230: return -1;
231: }
232:
233: if (!zcbuf) {
234: if (ioctl(eth, BIOCGBLEN, &n) == -1) {
235: LOGERR;
236: close(eth);
237: return -1;
238: } else
239: n = (buflen && *buflen) ? *buflen : getpagesize();
240:
241: if (ioctl(eth, BIOCSBLEN, &n) == -1) {
242: LOGERR;
243: close(eth);
244: return -1;
245: }
246: if (buflen)
247: *buflen = n;
248: } else {
249: #ifdef __FreeBSD__
250: n = BPF_BUFMODE_ZBUF;
251: if (ioctl(eth, BIOCSETBUFMODE, &n) == -1) {
252: LOGERR;
253: close(eth);
254: return -1;
255: }
256: if (ioctl(eth, BIOCGETZMAX, &n) == -1) {
257: LOGERR;
258: close(eth);
259: return -1;
260: } else
261: n = (buflen && *buflen) ? *buflen : n;
262: if (!(*zcbuf = allocZCbuf(n))) {
263: close(eth);
264: return -1;
265: }
266: if (ioctl(eth, BIOCSETZBUF, *zcbuf) == -1) {
267: LOGERR;
268: io_etherClose(eth, zcbuf);
269: return -1;
270: }
271: if (buflen && *buflen)
272: *buflen = n;
273: #endif
274: }
275:
276: memset(&ifr, 0, sizeof ifr);
277: strlcpy(ifr.ifr_name, szStr, sizeof ifr.ifr_name);
278: if (ioctl(eth, BIOCSETIF, &ifr) == -1) {
279: LOGERR;
280: io_etherClose(eth, zcbuf);
281: return -1;
282: }
283:
284: return eth;
285: }
286:
287: /*
288: * io_etherSend() - Send packet to bpf
289: *
290: * @eth = bpf handle
291: * @buf = buffer
292: * @buflen = buffer length
293: * return: -1 error or !=-1 written bytes
294: */
295: ssize_t
296: io_etherSend(int eth, const void *buf, size_t buflen)
297: {
298: ssize_t wlen = 0;
299:
300: if (!buf || !buflen) {
301: io_SetErr(EINVAL, "invalid arguments");
302: return -1;
303: }
304:
305: wlen = write(eth, buf, buflen);
306: if (wlen == -1)
307: LOGERR;
308: return wlen;
309: }
310:
311: #ifdef __FreeBSD__
312: static inline void
313: ackZCbuf(struct bpf_zbuf_header *bzh)
314: {
315: atomic_store_rel_int(&bzh->bzh_user_gen, bzh->bzh_kernel_gen);
316: }
317:
318: static inline int
319: chkZCbuf(struct bpf_zbuf_header *bzh)
320: {
321: /* return true if userspace owns buffer, and false otherwise. */
322: return (bzh->bzh_user_gen != atomic_load_acq_int(&bzh->bzh_kernel_gen));
323: }
324:
325: static ssize_t
326: nextZCbuf(int eth, struct bpf_zbuf * __restrict zbuf, void * __restrict buf, size_t buflen)
327: {
328: ssize_t rlen = 0;
329: struct bpf_zbuf bz;
330: struct bpf_zbuf_header *bzh;
331: off_t pos = 0;
332:
333: bzh = (struct bpf_zbuf_header *) zbuf->bz_bufa;
334: if (chkZCbuf(bzh)) {
335: rlen = MIN(atomic_load_acq_int(&bzh->bzh_kernel_len), buflen);
336: memcpy(buf + pos, zbuf->bz_bufa + sizeof(struct bpf_zbuf_header), rlen);
337: ackZCbuf(bzh);
338: pos += rlen;
339: }
340: bzh = (struct bpf_zbuf_header *) zbuf->bz_bufb;
341: if (chkZCbuf(bzh)) {
342: rlen = MIN(atomic_load_acq_int(&bzh->bzh_kernel_len), buflen);
343: memcpy(buf + pos, zbuf->bz_bufb + sizeof(struct bpf_zbuf_header), rlen);
344: ackZCbuf(bzh);
345: pos += rlen;
346: }
347:
348: if (!pos) {
349: if ((rlen = ioctl(eth, BIOCROTZBUF, &bz)) == -1)
350: LOGERR;
351: } else
352: rlen = pos;
353: return rlen;
354: }
355: #endif
356:
357: /*
358: * io_etherRecv() - Receive packet from bpf
359: *
360: * @eth = bpf handle
361: * @buf = buffer
362: * @buflen = buffer length
363: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
364: * return: -1 error or !=-1 readed bytes
365: */
366: ssize_t
367: io_etherRecv(int eth, void * __restrict buf, size_t buflen, void * __restrict zcbuf)
368: {
369: ssize_t rlen = 0;
370: struct bpf_hdr *h;
371:
372: if (!buf || !buflen) {
373: io_SetErr(EINVAL, "invalid arguments");
374: return -1;
375: }
376:
377: if (!zcbuf) {
378: rlen = read(eth, buf, buflen);
379: if (rlen == -1) {
380: LOGERR;
381: return -1;
382: }
383: } else {
384: #ifdef __FreeBSD__
385: rlen = nextZCbuf(eth, (struct bpf_zbuf*) zcbuf, buf, buflen);
386: if (!rlen)
387: rlen = nextZCbuf(eth, (struct bpf_zbuf*) zcbuf, buf, buflen);
388: #else
389: rlen = -1;
390: io_SetErr(ENOTSUP, "bpf zero copy buffer mode is not supported");
391: #endif
392: }
393:
394: h = (struct bpf_hdr*) buf;
395: rlen -= h->bh_hdrlen;
396:
397: if (h->bh_caplen != rlen) {
398: if (h->bh_caplen < rlen)
399: rlen = h->bh_caplen;
400: else {
401: io_SetErr(EIO, "Captured %d bytes should be at most %d bytes",
402: h->bh_caplen, rlen);
403: return -1;
404: }
405: }
406:
407: memmove(buf, buf + h->bh_hdrlen, rlen);
408: return rlen;
409: }
410:
411: /*
412: * io_etherFilter() - BPF filter routine
413: *
414: * @eth = bpf handle
415: * @io = filter direction
416: * (IO_ETHER_FILTER_PROMISC|IO_ETHER_FILTER_NOTREAD|IO_ETHER_FILTER_READ|IO_ETHER_FILTER_WRITE)
417: * @insn = BPF filter instruction array
418: * @insnlen = Length of BPF filter instruction array
419: * return: -1 error or 0 ok
420: */
421: int
422: io_etherFilter(int eth, int io, struct bpf_insn * __restrict insn, size_t insnlen)
423: {
424: int ret = 0;
425: struct bpf_program fcode = { 0 };
426:
427: if (io != IO_ETHER_FILTER_PROMISC && (!insn || !insnlen)) {
428: io_SetErr(EINVAL, "invalid arguments");
429: return -1;
430: }
431:
432: switch (io) {
433: case IO_ETHER_FILTER_PROMISC: /* promiscuous mode */
434: ret = ioctl(eth, BIOCPROMISC, NULL);
435: break;
436: case IO_ETHER_FILTER_NOTREAD: /* read not filter */
437: fcode.bf_len = insnlen / sizeof(struct bpf_insn);
438: fcode.bf_insns = insn;
439: ret = ioctl(eth, BIOCSETFNR, &fcode);
440: break;
441: case IO_ETHER_FILTER_READ: /* read filter */
442: fcode.bf_len = insnlen / sizeof(struct bpf_insn);
443: fcode.bf_insns = insn;
444: ret = ioctl(eth, BIOCSETF, &fcode);
445: break;
446: case IO_ETHER_FILTER_WRITE: /* write filter */
447: fcode.bf_len = insnlen / sizeof(struct bpf_insn);
448: fcode.bf_insns = insn;
449: ret = ioctl(eth, BIOCSETWF, &fcode);
450: break;
451: }
452:
453: if (ret == -1)
454: LOGERR;
455: return ret;
456: }
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