dist/src/bpf.c

43 #include <net/bpf.h>
54 #include "bpf.h"
148 struct bpf *
150     int (*filter)(const struct bpf *, const struct in_addr *),
153 	struct bpf *bpf;
169 	bpf = calloc(1, sizeof(*bpf));
170 	if (bpf == NULL)
172 	bpf->bpf_ifp = ifp;
174 	/* /dev/bpf is a cloner on modern kernels */
175 	bpf->bpf_fd = open("/dev/bpf", BPF_OPEN_FLAGS);
177 	/* Support older kernels where /dev/bpf is not a cloner */
178 	if (bpf->bpf_fd == -1) {
183 			snprintf(device, sizeof(device), "/dev/bpf%d", n++);
184 			bpf->bpf_fd = open(device, BPF_OPEN_FLAGS);
185 		} while (bpf->bpf_fd == -1 && errno == EBUSY);
188 	if (bpf->bpf_fd == -1)
192 	if ((fd_opts = fcntl(bpf->bpf_fd, F_GETFD)) == -1 ||
193 	    fcntl(bpf->bpf_fd, F_SETFD, fd_opts | FD_CLOEXEC) == -1)
197 	if (ioctl(bpf->bpf_fd, BIOCVERSION, &pv) == -1)
206 	if (ioctl(bpf->bpf_fd, BIOCSETIF, &ifr) == -1)
211 	if (ioctl(bpf->bpf_fd, BIOCIMMEDIATE, &flags) == -1)
215 	if (filter(bpf, ia) != 0)
219 	if (ioctl(bpf->bpf_fd, BIOCGBLEN, &ibuf_len) == -1)
221 	bpf->bpf_size = (size_t)ibuf_len;
222 	bpf->bpf_buffer = malloc(bpf->bpf_size);
223 	if (bpf->bpf_buffer == NULL)
225 	return bpf;
228 	if (bpf->bpf_fd != -1)
229 		close(bpf->bpf_fd);
230 	free(bpf);
237 bpf_read(struct bpf *bpf, void *data, size_t len)
243 	bpf->bpf_flags &= ~BPF_EOF;
245 		if (bpf->bpf_len == 0) {
246 			bytes = read(bpf->bpf_fd, bpf->bpf_buffer,
247 			    bpf->bpf_size);
252 				lseek(bpf->bpf_fd, 0, SEEK_SET);
258 			bpf->bpf_len = (size_t)bytes;
259 			bpf->bpf_pos = 0;
262 		payload = (const char *)bpf->bpf_buffer + bpf->bpf_pos;
264 		if (bpf->bpf_pos + packet.bh_caplen + packet.bh_hdrlen >
265 		    bpf->bpf_len)
272 		if (bpf_frame_bcast(bpf->bpf_ifp, payload) == 0)
273 			bpf->bpf_flags |= BPF_BCAST;
275 			bpf->bpf_flags &= ~BPF_BCAST;
278 		bpf->bpf_pos += BPF_WORDALIGN(packet.bh_hdrlen +
280 		if (bpf->bpf_pos >= bpf->bpf_len) {
281 			bpf->bpf_len = bpf->bpf_pos = 0;
282 			bpf->bpf_flags |= BPF_EOF;
315 bpf_send(const struct bpf *bpf, uint16_t protocol,
321 	switch(bpf->bpf_ifp->hwtype) {
324 		memcpy(&eh.ether_shost, bpf->bpf_ifp->hwaddr,
337 	return writev(bpf->bpf_fd, iov, 2);
342 bpf_close(struct bpf *bpf)
345 	close(bpf->bpf_fd);
346 	free(bpf->bpf_buffer);
347 	free(bpf);
353 bpf_cmp_hwaddr(struct bpf_insn *bpf, size_t bpf_len, size_t off,
390 	bp = bpf;
433 	return (unsigned int)(bp - bpf);
487 bpf_arp_rw(const struct bpf *bpf, const struct in_addr *ia, bool recv)
489 	const struct interface *ifp = bpf->bpf_ifp;
546 		return bpf_wattach(bpf->bpf_fd, buf, (unsigned int)(bp - buf));
549 	return bpf_attach(bpf->bpf_fd, buf, (unsigned int)(bp - buf));
553 bpf_arp(const struct bpf *bpf, const struct in_addr *ia)
557 	if (bpf_arp_rw(bpf, ia, true) == -1 ||
558 	    bpf_arp_rw(bpf, ia, false) == -1 ||
559 	    ioctl(bpf->bpf_fd, BIOCLOCK) == -1)
563 	return bpf_arp_rw(bpf, ia, true);
641 bpf_bootp_rw(const struct bpf *bpf, bool read)
648 	switch(bpf->bpf_ifp->hwtype) {
677 		return bpf_wattach(bpf->bpf_fd, buf, (unsigned int)(bp - buf));
690 	return bpf_attach(bpf->bpf_fd, buf, (unsigned int)(bp - buf));
694 bpf_bootp(const struct bpf *bpf, __unused const struct in_addr *ia)
698 	if (bpf_bootp_rw(bpf, true) == -1 ||
699 	    bpf_bootp_rw(bpf, false) == -1 ||
700 	    ioctl(bpf->bpf_fd, BIOCLOCK) == -1)
712 	return bpf_bootp_rw(bpf, true);