3 files changed, 122 insertions, 0 deletions
diff --git a/package/wprobe/src/filter/README.txt b/package/wprobe/src/filter/README.txt
new file mode 100644
index 000000000..6fa265e4f
--- /dev/null
+++ b/package/wprobe/src/filter/README.txt
@@ -0,0 +1 @@
+To compile pfc you need at least libpcap version 1.0, as it requires proper radiotap header support
diff --git a/package/wprobe/src/filter/gen_filter.pl b/package/wprobe/src/filter/gen_filter.pl
new file mode 100755
index 000000000..f03f477a4
--- /dev/null
+++ b/package/wprobe/src/filter/gen_filter.pl
@@ -0,0 +1,63 @@
+#!/usr/bin/perl
+use strict;
+
+# helpers for custom packet format
+# bytes 0-7 are used by a dummy radiotap header
+my $WLAN_LEN = "radio[8:2]";
+my $SNR = "radio[10:1]";
+my $DEFAULT = undef;
+
+my $MAGIC = "WPFF";
+my $VERSION = 1; # filter binary format version
+my $HDRLEN = 3; # assumed storage space for custom fields
+
+my $output = "filter.bin";
+my $config = {
+	"packetsize" => [
+		[ "small", "$WLAN_LEN < 250" ],
+		[ "medium", "$WLAN_LEN < 800" ],
+		[ "big", $DEFAULT ],
+	],
+	"snr" => [
+		[ "low", "$SNR < 10" ],
+		[ "medium", "$SNR < 20" ],
+		[ "high", $DEFAULT ],
+	],
+	"type" => [
+		[ "beacon", "type mgt subtype beacon" ],
+		[ "data", "type data subtype data" ],
+		[ "qosdata", "type data subtype qos-data" ],
+		[ "other", "$DEFAULT" ]
+	]
+};
+
+sub escape_q($) {
+	my $str = shift;
+	$str =~ s/'/'\\''/g;
+	return $str;
+}
+
+my $GROUPS = scalar(keys %$config);
+open OUTPUT, ">$output" or die "Cannot open output file: $!\n";
+print OUTPUT pack("a4CCn", $MAGIC, $VERSION, $HDRLEN, $GROUPS);
+
+foreach my $groupname (keys %$config) {
+	my $default = 0;
+	my $group = $config->{$groupname};
+	print OUTPUT pack("a32N", $groupname, scalar(@$group));
+	foreach my $filter (@$group) {
+		if (!$filter->[1]) {
+			$default > 0 and print "Cannot add more than one default filter per group: $groupname -> ".$filter->[0]."\n";
+			print OUTPUT pack("a32N", $filter->[0], 0);
+			$default++;
+		} else {
+			open FILTER, "./pfc '".escape_q($filter->[0])."' '".escape_q($filter->[1])."' |"
+				or die "Failed to run filter command for '".$filter->[0]."': $!\n";
+			while (<FILTER>) {
+				print OUTPUT $_;
+			}
+			close FILTER;
+			$? and die "Filter '".$filter->[0]."' did not compile.\n";
+		}
+	}
+}
diff --git a/package/wprobe/src/filter/pfc.c b/package/wprobe/src/filter/pfc.c
new file mode 100644
index 000000000..76fb1412a
--- /dev/null
+++ b/package/wprobe/src/filter/pfc.c
@@ -0,0 +1,58 @@
+#include <arpa/inet.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include <pcap.h>
+#include <pcap-bpf.h>
+
+struct wprobe_filter_hdr {
+	char name[32];
+	uint32_t len;
+} hdr;
+
+int main (int argc, char ** argv)
+{
+    struct  bpf_program filter;
+    pcap_t  *pc;
+	int i;
+
+    if (argc != 3)
+    {
+		fprintf(stderr, "Usage: %s <name> <expression>\n", argv[0]);
+		return 1;
+    }
+
+    pc = pcap_open_dead(DLT_IEEE802_11_RADIO, 256);
+    if (pcap_compile(pc, &filter, argv[2], 1, 0) != 0)
+	{
+		pcap_perror(pc, argv[0]);
+		exit(1);
+	}
+
+	/* fix up for linux */
+	for (i = 0; i < filter.bf_len; i++) {
+		struct bpf_insn *bi = &filter.bf_insns[i];
+		switch(BPF_CLASS(bi->code)) {
+		case BPF_RET:
+			if (BPF_MODE(bi->code) == BPF_K) {
+				if (bi->k != 0)
+					bi->k = 65535;
+			}
+			break;
+		}
+		bi->code = ntohs(bi->code);
+		bi->k = ntohl(bi->k);
+	}
+
+	memset(&hdr, 0, sizeof(hdr));
+	strncpy(hdr.name, argv[1], sizeof(hdr.name));
+	hdr.len = htonl(filter.bf_len);
+	fwrite(&hdr, sizeof(hdr), 1, stdout);
+	fwrite(filter.bf_insns, 8, filter.bf_len, stdout);
+	fflush(stdout);
+
+    return 0;
+}