svn commit: r333668 - vendor/tcpdump/dist

[Slava Shwartsman]

Author: slavash
Date: Wed May 16 08:43:08 2018
New Revision: 333668
URL: https://svnweb.freebsd.org/changeset/base/333668

Log:
  Vendor import two upstream commits:
  c1bb8784abd3ca978e376b0d10e324db0491237b
  9c4af7213cc2543a1f5586d8f2c19f86aa0cbe72
  
  When using tcpdump -I -i wlanN and wlanN is not a monitor mode VAP,
  tcpdump will print an error message saying rfmon is not supported.
  
  Give a concise explanation as to how one might solve this problem by
  creating a monitor mode VAP.
  
  Approved by:    hselasky (mentor), kib (mentor)
  Sponsored by:   Mellanox Technologies

Modified:
  vendor/tcpdump/dist/tcpdump.c

Modified: vendor/tcpdump/dist/tcpdump.c
==============================================================================
--- vendor/tcpdump/dist/tcpdump.c	Wed May 16 06:52:08 2018	(r333667)
+++ vendor/tcpdump/dist/tcpdump.c	Wed May 16 08:43:08 2018	(r333668)
@@ -108,6 +108,10 @@ The Regents of the University of California.  All righ
 #endif /* HAVE_CAP_NG_H */
 #endif /* HAVE_LIBCAP_NG */
 
+#ifdef __FreeBSD__
+#include <sys/sysctl.h>
+#endif /* __FreeBSD__ */
+
 #include "netdissect.h"
 #include "interface.h"
 #include "addrtoname.h"
@@ -1044,6 +1048,30 @@ open_interface(const char *device, netdissect_options 
 		} else if (status == PCAP_ERROR_PERM_DENIED && *cp != '\0')
 			error("%s: %s\n(%s)", device,
 			    pcap_statustostr(status), cp);
+#ifdef __FreeBSD__
+		else if (status == PCAP_ERROR_RFMON_NOTSUP &&
+		    strncmp(device, "wlan", 4) == 0) {
+			char parent[8], newdev[8];
+			char sysctl[32];
+			size_t s = sizeof(parent);
+
+			snprintf(sysctl, sizeof(sysctl),
+			    "net.wlan.%d.%%parent", atoi(device + 4));
+			sysctlbyname(sysctl, parent, &s, NULL, 0);
+			strlcpy(newdev, device, sizeof(newdev));
+			/* Suggest a new wlan device. */
+			/* FIXME: incrementing the index this way is not going to work well
+			 * when the index is 9 or greater but the only consequence in this
+			 * specific case would be an error message that looks a bit odd.
+			 */
+			newdev[strlen(newdev)-1]++;
+			error("%s is not a monitor mode VAP\n"
+			    "To create a new monitor mode VAP use:\n"
+			    "  ifconfig %s create wlandev %s wlanmode monitor\n"
+			    "and use %s as the tcpdump interface",
+			    device, newdev, parent, newdev);
+		}
+#endif
 		else
 			error("%s: %s", device,
 			    pcap_statustostr(status));