Display interface and index and name on DLT_LINUX_SLL2

Index is displayed always, name only if available.

Warn about possible wrong interfaces when in reading mode
(pcap file can be displayed on a different host then where
was captured) [1].

See: GH the-tcpdump-group/libpcap#127

[1] https://lists.sandelman.ca/pipermail/tcpdump-workers/2018-July/001019.html

Signed-off-by: Petr Vorel <pvorel@suse.cz>
Suggested-by: Guy Harris <guy@alum.mit.edu>
Reviewed-by: Denis Ovsienko <denis@ovsienko.info>
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 4 insertions, 0 deletions

diff --git a/tcpdump.c b/tcpdump.c
index 2bef72c8..0ef21117 100644
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -1978,6 +1978,10 @@ main(int argc, char **argv)
 			    RFileName, dlt_name,
 			    pcap_datalink_val_to_description(dlt));
 		}
+#ifdef DLT_LINUX_SLL2
+		if (dlt == DLT_LINUX_SLL2)
+			fprintf(stderr, "Warning: interface names might be incorrect\n");
+#endif
 	} else {
 		/*
 		 * We're doing a live capture.