On Linux, handle all CAN captures with pcap-linux.c, in cooked mode.

There's no need to support capturing on PF_CAN sockets; CAN interfaces
show up as regular interfaces on which you can capture with PF_PACKET
sockets, so just let pcap-linux.c handle them, and get rid of
pcap-can-linux.c.

Capture on them in cooked mode, so we get the protocol field and can
distinguish between "classic" CAN and CAN FD.

The hardware for which pcap-canusb-linux.c was intended never reached
production:

    https://github.com/axos88/libpcap/commit/f3edbb599b8cbcc7e4560000dcba8e992dc11a31#commitcomment-18716617

so we don't need pcap-canusb-linux.c, either.

This all removes the need for the "host-endian" link-layer header type;
it never made it into a libpcap release, so we just remove it.  The
"big-endian" link-layer header type is kept for the benefit of packets
captured with the old pcap-can-linux.c code; we revert it to its old
name.

1 files changed, 6 insertions, 16 deletions

diff --git a/pcap-linux.c b/pcap-linux.c
index a2ace7b7..b7fb6889 100644
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -2944,23 +2944,13 @@ static void map_arphrd_to_dlt(pcap_t *handle, int sock_fd, int arptype,
 #endif
 	case ARPHRD_CAN:
 		/*
-		 * DLT_CAN_SOCKETCAN_BIGENDIAN is defined to have the
-		 * can_id field of the pseudo-header in big-endian
-		 * (network) byte order.
-		 *
-		 * The packets delivered to sockets have that field
-		 * in host byte order.
-		 *
-		 * The code that implements it in packet-can-linux.c
-		 * passes that field to htonl() to put it into network
-		 * byte order.
-		 *
-		 * The code that reads from a PF_PACKET socket doesn't
-		 * change the byte order of that field, so we define
-		 * a new DLT_CAN_SOCKETCAN_HOSTENDIAN, where the can_id
-		 * is in host byte order.
+		 * Map this to DLT_LINUX_SLL; that way, CAN frames will
+		 * have ETH_P_CAN/LINUX_SLL_P_CAN as the protocol and
+		 * CAN FD frames will have ETH_P_CANFD/LINUX_SLL_P_CANFD
+		 * as the protocol, so they can be distinguished by the
+		 * protocol in the SLL header.
 		 */
-		handle->linktype = DLT_CAN_SOCKETCAN_HOSTENDIAN;
+		handle->linktype = DLT_LINUX_SLL;
 		break;
 
 #ifndef ARPHRD_IEEE802_TR