auto import from //depot/cupcake/@135843

1 files changed, 206 insertions, 0 deletions

diff --git a/bpf.c b/bpf.c
new file mode 100644
index 0000000..96e53a1
--- /dev/null
+++ b/bpf.c
@@ -0,0 +1,206 @@
+/*
+ * dhcpcd - DHCP client daemon
+ * Copyright 2006-2008 Roy Marples <roy@marples.name>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+
+#include <net/bpf.h>
+#include <net/if.h>
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <paths.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "config.h"
+#include "common.h"
+#include "dhcp.h"
+#include "logger.h"
+#include "net.h"
+#include "bpf-filter.h"
+
+int
+open_socket(struct interface *iface, int protocol)
+{
+	int fd = -1;
+	int *fdp = NULL;
+	struct ifreq ifr;
+	int buf_len = 0;
+	struct bpf_version pv;
+	struct bpf_program pf;
+#ifdef BIOCIMMEDIATE
+	int flags;
+#endif
+#ifdef _PATH_BPF
+	fd = open(_PATH_BPF, O_RDWR | O_NONBLOCK);
+#else
+	char *device;
+	int n = 0;
+
+	device = xmalloc(sizeof(char) * PATH_MAX);
+	do {
+		snprintf(device, PATH_MAX, "/dev/bpf%d", n++);
+		fd = open(device, O_RDWR | O_NONBLOCK);
+	} while (fd == -1 && errno == EBUSY);
+	free(device);
+#endif
+
+	if (fd == -1)
+		return -1;
+
+	if (ioctl(fd, BIOCVERSION, &pv) == -1)
+		goto eexit;
+	if (pv.bv_major != BPF_MAJOR_VERSION ||
+	    pv.bv_minor < BPF_MINOR_VERSION) {
+		logger(LOG_ERR, "BPF version mismatch - recompile " PACKAGE);
+		goto eexit;
+	}
+
+	memset(&ifr, 0, sizeof(ifr));
+	strlcpy(ifr.ifr_name, iface->name, sizeof(ifr.ifr_name));
+	if (ioctl(fd, BIOCSETIF, &ifr) == -1)
+		goto eexit;
+
+	/* Get the required BPF buffer length from the kernel. */
+	if (ioctl(fd, BIOCGBLEN, &buf_len) == -1)
+		goto eexit;
+	if (iface->buffer_size != (size_t)buf_len) {
+		free(iface->buffer);
+		iface->buffer_size = buf_len;
+		iface->buffer = xmalloc(buf_len);
+		iface->buffer_len = iface->buffer_pos = 0;
+	}
+
+#ifdef BIOCIMMEDIATE
+	flags = 1;
+	if (ioctl(fd, BIOCIMMEDIATE, &flags) == -1)
+		goto eexit;
+#endif
+
+	/* Install the DHCP filter */
+	if (protocol == ETHERTYPE_ARP) {
+		pf.bf_insns = UNCONST(arp_bpf_filter);
+		pf.bf_len = arp_bpf_filter_len;
+		fdp = &iface->arp_fd;
+	} else {
+		pf.bf_insns = UNCONST(dhcp_bpf_filter);
+		pf.bf_len = dhcp_bpf_filter_len;
+		fdp = &iface->raw_fd;
+	}
+	if (ioctl(fd, BIOCSETF, &pf) == -1)
+		goto eexit;
+	if (set_cloexec(fd) == -1)
+		goto eexit;
+	if (fdp) {
+		if (*fdp != -1)
+			close(*fdp);
+		*fdp = fd;
+	}
+	return fd;
+
+eexit:
+	free(iface->buffer);
+	iface->buffer = NULL;
+	close(fd);
+	return -1;
+}
+
+ssize_t
+send_raw_packet(const struct interface *iface, int protocol,
+		const void *data, ssize_t len)
+{
+	struct iovec iov[2];
+	struct ether_header hw;
+	int fd;
+
+	memset(&hw, 0, ETHER_HDR_LEN);
+	memset(&hw.ether_dhost, 0xff, ETHER_ADDR_LEN);
+	hw.ether_type = htons(protocol);
+	iov[0].iov_base = &hw;
+	iov[0].iov_len = ETHER_HDR_LEN;
+	iov[1].iov_base = UNCONST(data);
+	iov[1].iov_len = len;
+	if (protocol == ETHERTYPE_ARP)
+		fd = iface->arp_fd;
+	else
+		fd = iface->raw_fd;
+	return writev(fd, iov, 2);
+}
+
+/* BPF requires that we read the entire buffer.
+ * So we pass the buffer in the API so we can loop on >1 packet. */
+ssize_t
+get_raw_packet(struct interface *iface, int protocol,
+	       void *data, ssize_t len)
+{
+	int fd = -1;
+	struct bpf_hdr packet;
+	ssize_t bytes;
+	const unsigned char *payload;
+
+	if (protocol == ETHERTYPE_ARP)
+		fd = iface->arp_fd;
+	else
+		fd = iface->raw_fd;
+
+	for (;;) {
+		if (iface->buffer_len == 0) {
+			bytes = read(fd, iface->buffer, iface->buffer_size);
+			if (bytes == -1)
+				return errno == EAGAIN ? 0 : -1;
+			else if ((size_t)bytes < sizeof(packet))
+				return -1;
+			iface->buffer_len = bytes;
+			iface->buffer_pos = 0;
+		}
+		bytes = -1;
+		memcpy(&packet, iface->buffer + iface->buffer_pos,
+		       sizeof(packet));
+		if (packet.bh_caplen != packet.bh_datalen)
+			goto next; /* Incomplete packet, drop. */
+		if (iface->buffer_pos + packet.bh_caplen + packet.bh_hdrlen >
+		    iface->buffer_len)
+			goto next; /* Packet beyond buffer, drop. */
+		payload = iface->buffer + packet.bh_hdrlen + ETHER_HDR_LEN;
+		bytes = packet.bh_caplen - ETHER_HDR_LEN;
+		if (bytes > len)
+			bytes = len;
+		memcpy(data, payload, bytes);
+next:
+		iface->buffer_pos += BPF_WORDALIGN(packet.bh_hdrlen +
+						   packet.bh_caplen);
+		if (iface->buffer_pos >= iface->buffer_len)
+			iface->buffer_len = iface->buffer_pos = 0;
+		if (bytes != -1)
+			return bytes;
+	}
+}