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 1.6 2014/02/08 22:06:17 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 - 2014
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: #if defined(__FreeBSD__) && defined(ZCBUF_ENABLE)
118: struct bpf_zbuf *zbuf = NULL;
119: #endif
120:
121: if (eth > STDERR_FILENO)
122: close(eth);
123:
124: if (zcbuf && *zcbuf) {
125: #if defined(__FreeBSD__) && defined(ZCBUF_ENABLE)
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: #if defined(__FreeBSD__) && defined(ZCBUF_ENABLE)
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, u_int whdr, u_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: #if !defined(__FreeBSD__) || !defined(ZCBUF_ENABLE)
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 (ioctl(eth, BIOCIMMEDIATE, &n) == -1) {
223: LOGERR;
224: close(eth);
225: return -1;
226: }
227:
228: if (!zcbuf) {
229: if (ioctl(eth, BIOCGBLEN, &n) == -1) {
230: LOGERR;
231: close(eth);
232: return -1;
233: } else
234: n = (buflen && *buflen) ? *buflen : getpagesize();
235:
236: if (ioctl(eth, BIOCSBLEN, &n) == -1) {
237: LOGERR;
238: close(eth);
239: return -1;
240: }
241: if (buflen)
242: *buflen = n;
243: } else {
244: #if defined(__FreeBSD__) && defined(ZCBUF_ENABLE)
245: n = BPF_BUFMODE_ZBUF;
246: if (ioctl(eth, BIOCSETBUFMODE, &n) == -1) {
247: LOGERR;
248: close(eth);
249: return -1;
250: }
251: if (ioctl(eth, BIOCGETZMAX, &n) == -1) {
252: LOGERR;
253: close(eth);
254: return -1;
255: } else
256: n = (buflen && *buflen) ? *buflen : n;
257: if (!(*zcbuf = allocZCbuf(n))) {
258: close(eth);
259: return -1;
260: }
261: if (ioctl(eth, BIOCSETZBUF, *zcbuf) == -1) {
262: LOGERR;
263: io_etherClose(eth, zcbuf);
264: return -1;
265: }
266: if (buflen && *buflen)
267: *buflen = n;
268: #endif
269: }
270:
271: memset(&ifr, 0, sizeof ifr);
272: strlcpy(ifr.ifr_name, szStr, sizeof ifr.ifr_name);
273: if (ioctl(eth, BIOCSETIF, &ifr) == -1) {
274: LOGERR;
275: io_etherClose(eth, zcbuf);
276: return -1;
277: }
278:
279: n = wdlt;
280: if (wdlt && ioctl(eth, BIOCSDLT, &n) == -1) {
281: LOGERR;
282: close(eth);
283: return -1;
284: }
285:
286: return eth;
287: }
288:
289: /*
290: * io_etherSend() - Send packet to bpf
291: *
292: * @eth = bpf handle
293: * @buf = buffer
294: * @buflen = buffer length
295: * return: -1 error or !=-1 written bytes
296: */
297: ssize_t
298: io_etherSend(int eth, const void *buf, size_t buflen)
299: {
300: ssize_t wlen = 0;
301:
302: if (!buf || !buflen) {
303: io_SetErr(EINVAL, "invalid arguments");
304: return -1;
305: }
306:
307: wlen = write(eth, buf, buflen);
308: if (wlen == -1)
309: LOGERR;
310: return wlen;
311: }
312:
313: #if defined(__FreeBSD__) && defined(ZCBUF_ENABLE)
314: static inline void
315: ackZCbuf(struct bpf_zbuf_header *bzh)
316: {
317: atomic_store_rel_int(&bzh->bzh_user_gen, bzh->bzh_kernel_gen);
318: }
319:
320: static inline int
321: chkZCbuf(struct bpf_zbuf_header *bzh)
322: {
323: /* return true if userspace owns buffer, and false otherwise. */
324: return (bzh->bzh_user_gen != atomic_load_acq_int(&bzh->bzh_kernel_gen));
325: }
326:
327: static ssize_t
328: nextZCbuf(int eth, struct bpf_zbuf * __restrict zbuf, void * __restrict buf, size_t buflen)
329: {
330: ssize_t rlen = 0;
331: struct bpf_zbuf bz;
332: struct bpf_zbuf_header *bzh;
333: off_t pos = 0;
334:
335: bzh = (struct bpf_zbuf_header *) zbuf->bz_bufa;
336: if (chkZCbuf(bzh)) {
337: rlen = MIN(atomic_load_acq_int(&bzh->bzh_kernel_len), buflen);
338: memcpy(buf + pos, zbuf->bz_bufa + sizeof(struct bpf_zbuf_header), rlen);
339: ackZCbuf(bzh);
340: pos += rlen;
341: }
342: bzh = (struct bpf_zbuf_header *) zbuf->bz_bufb;
343: if (chkZCbuf(bzh)) {
344: rlen = MIN(atomic_load_acq_int(&bzh->bzh_kernel_len), buflen);
345: memcpy(buf + pos, zbuf->bz_bufb + sizeof(struct bpf_zbuf_header), rlen);
346: ackZCbuf(bzh);
347: pos += rlen;
348: }
349:
350: if (!pos) {
351: if ((rlen = ioctl(eth, BIOCROTZBUF, &bz)) == -1)
352: LOGERR;
353: } else
354: rlen = pos;
355: return rlen;
356: }
357: #endif
358:
359: /*
360: * io_etherRecv() - Receive packet from bpf
361: *
362: * @eth = bpf handle
363: * @buf = buffer
364: * @buflen = buffer length
365: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
366: * return: -1 error or !=-1 readed bytes
367: */
368: ssize_t
369: io_etherRecv(int eth, void * __restrict buf, size_t buflen, void * __restrict zcbuf)
370: {
371: ssize_t rlen = 0;
372: struct bpf_hdr *h;
373:
374: if (!buf || !buflen) {
375: io_SetErr(EINVAL, "invalid arguments");
376: return -1;
377: }
378:
379: if (!zcbuf) {
380: rlen = read(eth, buf, buflen);
381: if (rlen == -1) {
382: LOGERR;
383: return -1;
384: }
385: } else {
386: #if defined(__FreeBSD__) && defined(ZCBUF_ENABLE)
387: rlen = nextZCbuf(eth, (struct bpf_zbuf*) zcbuf, buf, buflen);
388: if (!rlen)
389: rlen = nextZCbuf(eth, (struct bpf_zbuf*) zcbuf, buf, buflen);
390: #else
391: rlen = -1;
392: io_SetErr(ENOTSUP, "bpf zero copy buffer mode is not supported");
393: #endif
394: }
395:
396: h = (struct bpf_hdr*) buf;
397: rlen -= h->bh_hdrlen;
398:
399: if (h->bh_caplen != rlen) {
400: if (h->bh_caplen < rlen)
401: rlen = h->bh_caplen;
402: else {
403: io_SetErr(EIO, "Captured %d bytes should be at most %d bytes",
404: h->bh_caplen, rlen);
405: return -1;
406: }
407: }
408:
409: memmove(buf, buf + h->bh_hdrlen, rlen);
410: return rlen;
411: }
412:
413: /*
414: * io_etherFilter() - BPF filter routine
415: *
416: * @eth = bpf handle
417: * @io = filter direction
418: * (IO_ETHER_FILTER_PROMISC|IO_ETHER_FILTER_NOTREAD|IO_ETHER_FILTER_READ|IO_ETHER_FILTER_WRITE)
419: * @insn = BPF filter instruction array
420: * @insnlen = Length of BPF filter instruction array
421: * return: -1 error or 0 ok
422: */
423: int
424: io_etherFilter(int eth, int io, struct bpf_insn * __restrict insn, size_t insnlen)
425: {
426: int ret = 0;
427: struct bpf_program fcode = { 0 };
428:
429: if (io != IO_ETHER_FILTER_PROMISC && (!insn || !insnlen)) {
430: io_SetErr(EINVAL, "invalid arguments");
431: return -1;
432: }
433:
434: switch (io) {
435: case IO_ETHER_FILTER_PROMISC: /* promiscuous mode */
436: ret = ioctl(eth, BIOCPROMISC, NULL);
437: break;
438: case IO_ETHER_FILTER_NOTREAD: /* read not filter */
439: fcode.bf_len = insnlen / sizeof(struct bpf_insn);
440: fcode.bf_insns = insn;
441: ret = ioctl(eth, BIOCSETFNR, &fcode);
442: break;
443: case IO_ETHER_FILTER_READ: /* read filter */
444: fcode.bf_len = insnlen / sizeof(struct bpf_insn);
445: fcode.bf_insns = insn;
446: ret = ioctl(eth, BIOCSETF, &fcode);
447: break;
448: case IO_ETHER_FILTER_WRITE: /* write filter */
449: fcode.bf_len = insnlen / sizeof(struct bpf_insn);
450: fcode.bf_insns = insn;
451: ret = ioctl(eth, BIOCSETWF, &fcode);
452: break;
453: }
454:
455: if (ret == -1)
456: LOGERR;
457: return ret;
458: }
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