wlantest: Add -N command line argument to remove write buffering

This makes it easier to do live parsing of captured pcap files from
wlantest without having to rename and restart the capture file. Packet
writes are flushed to disk after each packet if -N is included in the
command line.

Signed-off-by: Jouni Malinen <j@w1.fi>

wlantest/readpcap.c

@@ -102,6 +102,8 @@ int read_cap_file(struct wlantest *wt, const char *fname)
 				write_pcap_with_radiotap(wt, data, hdr->caplen);
 			else
 				pcap_dump(wt->write_pcap_dumper, hdr, data);
+			if (wt->pcap_no_buffer)
+				pcap_dump_flush(wt->write_pcap_dumper);
 		}
 		if (hdr->caplen < hdr->len) {
 			add_note(wt, MSG_DEBUG, "pcap: Dropped incomplete "

wlantest/wlantest.c

@@ -21,7 +21,7 @@ static void wlantest_terminate(int sig, void *signal_ctx)
 
 static void usage(void)
 {
-	printf("wlantest [-cddhqqFt] [-i<ifname>] [-r<pcap file>] "
+	printf("wlantest [-cddhqqFNt] [-i<ifname>] [-r<pcap file>] "
 	       "[-p<passphrase>]\n"
 	       "         [-I<wired ifname>] [-R<wired pcap file>] "
 	       "[-P<RADIUS shared secret>]\n"
@@ -350,7 +350,7 @@ int main(int argc, char *argv[])
 	wlantest_init(&wt);
 
 	for (;;) {
-		c = getopt(argc, argv, "cdf:Fhi:I:L:n:p:P:qr:R:tT:w:W:");
+		c = getopt(argc, argv, "cdf:Fhi:I:L:n:Np:P:qr:R:tT:w:W:");
 		if (c < 0)
 			break;
 		switch (c) {
@@ -383,6 +383,9 @@ int main(int argc, char *argv[])
 		case 'n':
 			wt.pcapng_file = optarg;
 			break;
+		case 'N':
+			wt.pcap_no_buffer = 1;
+			break;
 		case 'p':
 			add_passphrase(&wt, optarg);
 			break;

wlantest/wlantest.h

@@ -202,6 +202,7 @@ struct wlantest {
 	int last_mgmt_valid;
 
 	unsigned int assume_fcs:1;
+	unsigned int pcap_no_buffer:1;
 
 	char *notes[MAX_NOTES];
 	size_t num_notes;

wlantest/writepcap.c

@@ -59,6 +59,8 @@ void write_pcap_captured(struct wlantest *wt, const u8 *buf, size_t len)
 	h.caplen = len;
 	h.len = len;
 	pcap_dump(wt->write_pcap_dumper, &h, buf);
+	if (wt->pcap_no_buffer)
+		pcap_dump_flush(wt->write_pcap_dumper);
 }
 
 
@@ -102,6 +104,8 @@ void write_pcap_decrypted(struct wlantest *wt, const u8 *buf1, size_t len1,
 	h.caplen = len;
 	h.len = len;
 	pcap_dump(wt->write_pcap_dumper, &h, buf);
+	if (wt->pcap_no_buffer)
+		pcap_dump_flush(wt->write_pcap_dumper);
 }
 
 
@@ -181,6 +185,8 @@ int write_pcapng_init(struct wlantest *wt, const char *fname)
 	desc.link_type = LINKTYPE_IEEE802_11_RADIO;
 	desc.snap_len = 65535;
 	fwrite(&desc, sizeof(desc), 1, wt->pcapng);
+	if (wt->pcap_no_buffer)
+		fflush(wt->pcapng);
 
 	return 0;
 }
@@ -263,6 +269,8 @@ static void write_pcapng_decrypted(struct wlantest *wt)
 	*block_len = pkt->block_total_len = pos - (u8 *) pkt;
 
 	fwrite(pkt, pos - (u8 *) pkt, 1, wt->pcapng);
+	if (wt->pcap_no_buffer)
+		fflush(wt->pcapng);
 
 	os_free(pkt);
 }
@@ -337,6 +345,8 @@ void write_pcapng_write_read(struct wlantest *wt, int dlt,
 	*block_len = pkt->block_total_len = pos - (u8 *) pkt;
 
 	fwrite(pkt, pos - (u8 *) pkt, 1, wt->pcapng);
+	if (wt->pcap_no_buffer)
+		fflush(wt->pcapng);
 
 	os_free(pkt);