Have separate DLTs for big-endian and host-endian SocketCAN headers.

At least with some versions of the Linux kernel, you can capture on
SocketCAN interfaces with a PF_PACKET socket and get packets with
SocketCAN headers; that code doesn't special-case ARPHRD_CAN, so it
leaves the CAN ID field in host byte order.

In addition, the "capture CAN packets on a USB device" code wasn't
putting that field into host byte order, either.

So have separate DLT_/LINKTYPE_ types, one for packets with the CAN ID
in big-endian byte order and one for packets with the CAN ID in host
byte order.  When reading LINKTYPE_CAN_SOCKETCAN_HOSTENDIAN files, swap
the CAN ID field as necessary to put it into the byte order for the host
reading the file rather than the byte order for the host that wrote the
file.

1 files changed, 54 insertions, 0 deletions

diff --git a/pcap/can_socketcan.h b/pcap/can_socketcan.h
new file mode 100644
index 00000000..68d2a131
--- /dev/null
+++ b/pcap/can_socketcan.h
@@ -0,0 +1,54 @@
+/*-
+ * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from the Stanford/CMU enet packet filter,
+ * (net/enet.c) distributed as part of 4.3BSD, and code contributed
+ * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
+ * Berkeley Laboratory.
+ *
+ * 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed by the University of
+ *      California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+ */
+
+#ifndef lib_pcap_can_socketcan_h
+#define lib_pcap_can_socketcan_h
+
+/*
+ * SocketCAN header, as per Documentation/networking/can.txt in the
+ * Linux source.
+ */
+typedef struct {
+	u_int32_t can_id;
+	u_int8_t payload_length;
+	u_int8_t pad;
+	u_int8_t reserved1;
+	u_int8_t reserved2;
+} pcap_can_socketcan_hdr;
+
+#endif