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 1.8 2016/08/18 09:06:31 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 - 2016
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_etherClose() - Close BPF interface
51: *
52: * @eth = bpf handle
53: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
54: * return: none
55: */
56: void
57: io_etherClose(int eth, void **zcbuf)
58: {
59: #if defined(__FreeBSD__) && defined(ZCBUF_ENABLE)
60: struct bpf_zbuf *zbuf = NULL;
61: #endif
62:
63: if (eth > STDERR_FILENO)
64: close(eth);
65:
66: #if defined(__FreeBSD__) && defined(ZCBUF_ENABLE)
67: if (zcbuf && *zcbuf) {
68: zbuf = *zcbuf;
69: munmap(zbuf->bz_bufb, zbuf->bz_buflen);
70: munmap(zbuf->bz_bufa, zbuf->bz_buflen);
71: e_free(*zcbuf);
72: *zcbuf = NULL;
73: }
74: #endif
75: }
76:
77: #if defined(__FreeBSD__) && defined(ZCBUF_ENABLE)
78: static inline struct bpf_zbuf *
79: allocZCbuf(u_int len)
80: {
81: struct bpf_zbuf *zbuf = NULL;
82:
83: zbuf = e_malloc(sizeof(struct bpf_zbuf));
84: if (!zbuf) {
85: io_SetErr(elwix_GetErrno(), "%s", elwix_GetError());
86: return NULL;
87: } else
88: memset(zbuf, 0, sizeof(struct bpf_zbuf));
89:
90: zbuf->bz_buflen = roundup(len, getpagesize());
91: zbuf->bz_bufa = mmap(NULL, zbuf->bz_buflen, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
92: if (zbuf->bz_bufa == MAP_FAILED) {
93: LOGERR;
94: e_free(zbuf);
95: return NULL;
96: } else
97: memset(zbuf->bz_bufa, 0, zbuf->bz_buflen);
98: zbuf->bz_bufb = mmap(NULL, zbuf->bz_buflen, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
99: if (zbuf->bz_bufb == MAP_FAILED) {
100: LOGERR;
101: munmap(zbuf->bz_bufa, zbuf->bz_buflen);
102: e_free(zbuf);
103: return NULL;
104: } else
105: memset(zbuf->bz_bufb, 0, zbuf->bz_buflen);
106:
107: return zbuf;
108: }
109: #endif
110:
111: /*
112: * io_etherOpen() - Open BPF interface to device
113: *
114: * @csIface = interface name
115: * @flags = open flags
116: * @whdr = with complete headers
117: * @wdlt = with data link type, on Linux is protocol number
118: * @buflen = buffer length
119: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
120: * return: -1 error or >-1 bpf handle
121: */
122: int
123: io_etherOpen(const char *csIface, int flags, u_int whdr, u_int wdlt,
124: u_int *buflen, void **zcbuf)
125: {
126: int eth = -1;
127: char szStr[STRSIZ];
128: struct ifreq ifr;
129: #ifndef __linux__
130: register int i;
131: u_int n = 1;
132: #else
133: sockaddr_t sa = {{ 0 }};
134: #endif
135:
136: #if !defined(__FreeBSD__) || !defined(ZCBUF_ENABLE)
137: if (zcbuf) {
138: io_SetErr(ENOTSUP, "bpf zero copy buffer mode is not supported");
139: return -1;
140: }
141: #endif
142:
143: #ifndef __linux__
144: for (i = 0; i < BPF_DEV_MAX; i++) {
145: memset(szStr, 0, sizeof szStr);
146: snprintf(szStr, sizeof szStr, "/dev/bpf%d", i);
147: eth = open(szStr, flags);
148: if (eth > STDERR_FILENO)
149: break;
150: }
151: #else
152: eth = socket(AF_PACKET, whdr ? SOCK_RAW : SOCK_DGRAM, htons((u_short) wdlt));
153: #endif
154: if (eth < 3) {
155: LOGERR;
156: return -1;
157: }
158:
159: if (csIface)
160: strlcpy(szStr, csIface, sizeof szStr);
161: else if (e_get1stiface(szStr, sizeof szStr) == -1) {
162: close(eth);
163: return -1;
164: }
165:
166: #ifndef __linux__
167: n = 1;
168: if (whdr && ioctl(eth, BIOCSHDRCMPLT, &n) == -1) {
169: LOGERR;
170: close(eth);
171: return -1;
172: }
173: if (ioctl(eth, BIOCIMMEDIATE, &n) == -1) {
174: LOGERR;
175: close(eth);
176: return -1;
177: }
178:
179: if (!zcbuf) {
180: if (ioctl(eth, BIOCGBLEN, &n) == -1) {
181: LOGERR;
182: close(eth);
183: return -1;
184: } else
185: n = (buflen && *buflen) ? *buflen : getpagesize();
186:
187: if (ioctl(eth, BIOCSBLEN, &n) == -1) {
188: LOGERR;
189: close(eth);
190: return -1;
191: }
192: if (buflen)
193: *buflen = n;
194: } else {
195: #if defined(__FreeBSD__) && defined(ZCBUF_ENABLE)
196: n = BPF_BUFMODE_ZBUF;
197: if (ioctl(eth, BIOCSETBUFMODE, &n) == -1) {
198: LOGERR;
199: close(eth);
200: return -1;
201: }
202: if (ioctl(eth, BIOCGETZMAX, &n) == -1) {
203: LOGERR;
204: close(eth);
205: return -1;
206: } else
207: n = (buflen && *buflen) ? *buflen : n;
208: if (!(*zcbuf = allocZCbuf(n))) {
209: close(eth);
210: return -1;
211: }
212: if (ioctl(eth, BIOCSETZBUF, *zcbuf) == -1) {
213: LOGERR;
214: io_etherClose(eth, zcbuf);
215: return -1;
216: }
217: if (buflen && *buflen)
218: *buflen = n;
219: #endif
220: }
221:
222: memset(&ifr, 0, sizeof ifr);
223: strlcpy(ifr.ifr_name, szStr, sizeof ifr.ifr_name);
224: if (ioctl(eth, BIOCSETIF, &ifr) == -1) {
225: LOGERR;
226: io_etherClose(eth, zcbuf);
227: return -1;
228: }
229:
230: n = wdlt;
231: if (wdlt && ioctl(eth, BIOCSDLT, &n) == -1) {
232: LOGERR;
233: close(eth);
234: return -1;
235: }
236: #else
237: memset(&ifr, 0, sizeof ifr);
238: strlcpy(ifr.ifr_name, szStr, sizeof ifr.ifr_name);
239: if (ioctl(eth, SIOCGIFINDEX, &ifr)) {
240: LOGERR;
241: close(eth);
242: return -1;
243: }
244:
245: sa.sll.sll_family = AF_PACKET;
246: sa.sll.sll_ifindex = ifr.ifr_ifindex;
247: sa.sll.sll_protocol = htons((u_short) wdlt);
248: if (bind(eth, &sa.sa, sizeof(sa.sll)) == -1) {
249: LOGERR;
250: close(eth);
251: return -1;
252: }
253: #endif
254:
255: return eth;
256: }
257:
258: /*
259: * io_etherSend() - Send packet to bpf
260: *
261: * @eth = bpf handle
262: * @buf = buffer
263: * @buflen = buffer length
264: * return: -1 error or !=-1 written bytes
265: */
266: ssize_t
267: io_etherSend(int eth, const void *buf, size_t buflen)
268: {
269: ssize_t wlen = 0;
270:
271: if (!buf || !buflen) {
272: io_SetErr(EINVAL, "invalid arguments");
273: return -1;
274: }
275:
276: wlen = write(eth, buf, buflen);
277: if (wlen == -1)
278: LOGERR;
279: return wlen;
280: }
281:
282: #if defined(__FreeBSD__) && defined(ZCBUF_ENABLE)
283: static inline void
284: ackZCbuf(struct bpf_zbuf_header *bzh)
285: {
286: atomic_store_rel_int(&bzh->bzh_user_gen, bzh->bzh_kernel_gen);
287: }
288:
289: static inline int
290: chkZCbuf(struct bpf_zbuf_header *bzh)
291: {
292: /* return true if userspace owns buffer, and false otherwise. */
293: return (bzh->bzh_user_gen != atomic_load_acq_int(&bzh->bzh_kernel_gen));
294: }
295:
296: static ssize_t
297: nextZCbuf(int eth, struct bpf_zbuf * __restrict zbuf, void * __restrict buf, size_t buflen)
298: {
299: ssize_t rlen = 0;
300: struct bpf_zbuf bz;
301: struct bpf_zbuf_header *bzh;
302: off_t pos = 0;
303:
304: bzh = (struct bpf_zbuf_header *) zbuf->bz_bufa;
305: if (chkZCbuf(bzh)) {
306: rlen = MIN(atomic_load_acq_int(&bzh->bzh_kernel_len), buflen);
307: memcpy(buf + pos, zbuf->bz_bufa + sizeof(struct bpf_zbuf_header), rlen);
308: ackZCbuf(bzh);
309: pos += rlen;
310: }
311: bzh = (struct bpf_zbuf_header *) zbuf->bz_bufb;
312: if (chkZCbuf(bzh)) {
313: rlen = MIN(atomic_load_acq_int(&bzh->bzh_kernel_len), buflen);
314: memcpy(buf + pos, zbuf->bz_bufb + sizeof(struct bpf_zbuf_header), rlen);
315: ackZCbuf(bzh);
316: pos += rlen;
317: }
318:
319: if (!pos) {
320: if ((rlen = ioctl(eth, BIOCROTZBUF, &bz)) == -1)
321: LOGERR;
322: } else
323: rlen = pos;
324: return rlen;
325: }
326: #endif
327:
328: /*
329: * io_etherRecv() - Receive packet from bpf
330: *
331: * @eth = bpf handle
332: * @buf = buffer
333: * @buflen = buffer length
334: * @zcbuf = zero copy buffer, if BPF supports it and isn't NULL
335: * return: -1 error or !=-1 readed bytes
336: */
337: ssize_t
338: io_etherRecv(int eth, void * __restrict buf, size_t buflen, void * __restrict zcbuf)
339: {
340: ssize_t rlen = 0;
341: #ifndef __linux__
342: struct bpf_hdr *h;
343: #endif
344:
345: if (!buf || !buflen) {
346: io_SetErr(EINVAL, "invalid arguments");
347: return -1;
348: }
349:
350: if (!zcbuf) {
351: rlen = read(eth, buf, buflen);
352: if (rlen == -1) {
353: LOGERR;
354: return -1;
355: }
356: } else {
357: #if defined(__FreeBSD__) && defined(ZCBUF_ENABLE)
358: rlen = nextZCbuf(eth, (struct bpf_zbuf*) zcbuf, buf, buflen);
359: if (!rlen)
360: rlen = nextZCbuf(eth, (struct bpf_zbuf*) zcbuf, buf, buflen);
361: #else
362: rlen = -1;
363: io_SetErr(ENOTSUP, "bpf zero copy buffer mode is not supported");
364: #endif
365: }
366:
367: #ifndef __linux__
368: h = (struct bpf_hdr*) buf;
369: rlen -= h->bh_hdrlen;
370:
371: if (h->bh_caplen != rlen) {
372: if (h->bh_caplen < rlen)
373: rlen = h->bh_caplen;
374: else {
375: io_SetErr(EIO, "Captured %d bytes should be at most %d bytes",
376: h->bh_caplen, rlen);
377: return -1;
378: }
379: }
380:
381: memmove(buf, buf + h->bh_hdrlen, rlen);
382: #endif
383: return rlen;
384: }
385:
386: #ifndef __linux__
387: /*
388: * io_etherFilter() - BPF filter routine
389: *
390: * @eth = bpf handle
391: * @io = filter direction
392: * (IO_ETHER_FILTER_PROMISC|IO_ETHER_FILTER_NOTREAD|IO_ETHER_FILTER_READ|IO_ETHER_FILTER_WRITE)
393: * @insn = BPF filter instruction array
394: * @insnlen = Length of BPF filter instruction array
395: * return: -1 error or 0 ok
396: */
397: int
398: io_etherFilter(int eth, int io, struct bpf_insn * __restrict insn, size_t insnlen)
399: {
400: int ret = 0;
401: struct bpf_program fcode = { 0 };
402:
403: if (io != IO_ETHER_FILTER_PROMISC && (!insn || !insnlen)) {
404: io_SetErr(EINVAL, "invalid arguments");
405: return -1;
406: }
407:
408: switch (io) {
409: case IO_ETHER_FILTER_PROMISC: /* promiscuous mode */
410: ret = ioctl(eth, BIOCPROMISC, NULL);
411: break;
412: case IO_ETHER_FILTER_NOTREAD: /* read not filter */
413: fcode.bf_len = insnlen / sizeof(struct bpf_insn);
414: fcode.bf_insns = insn;
415: ret = ioctl(eth, BIOCSETFNR, &fcode);
416: break;
417: case IO_ETHER_FILTER_READ: /* read filter */
418: fcode.bf_len = insnlen / sizeof(struct bpf_insn);
419: fcode.bf_insns = insn;
420: ret = ioctl(eth, BIOCSETF, &fcode);
421: break;
422: case IO_ETHER_FILTER_WRITE: /* write filter */
423: fcode.bf_len = insnlen / sizeof(struct bpf_insn);
424: fcode.bf_insns = insn;
425: ret = ioctl(eth, BIOCSETWF, &fcode);
426: break;
427: }
428:
429: if (ret == -1)
430: LOGERR;
431: return ret;
432: }
433: #endif
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