Increased capture length and adjusted 802.11 header length for radiotap

support.

2 files changed, 6 insertions, 5 deletions

diff --git a/ether.h b/ether.h
index 26caf9b..cc0b3f2 100644
--- a/ether.h
+++ b/ether.h
@@ -28,6 +28,6 @@ struct radiotap_header {
         u_int8_t        it_pad;
         u_int16_t       it_len;         /* entire length */
         u_int32_t       it_present;     /* fields present */
-};
+} __attribute__((packed));
 
 #endif 
diff --git a/iftop.c b/iftop.c
index 0d46fc5..06778d6 100644
--- a/iftop.c
+++ b/iftop.c
@@ -86,9 +86,10 @@ static void finish(int sig) {
  * bytes of tcp/udp header */
 /* Increase with a further 20 to account for IPv6 header length.  */
 /* IEEE 802.11 radiotap throws in a variable length header plus 8 (radiotap
- * header header) plus 30 (802.11 MAC) plus 40 (IPv6) = 78, plus whatever's in
+ * header header) plus 34 (802.11 MAC) plus 40 (IPv6) = 78, plus whatever's in
  * the radiotap payload */
-#define CAPTURE_LENGTH 92
+/*#define CAPTURE_LENGTH 92 */
+#define CAPTURE_LENGTH 256
 
 void init_history() {
     history = addr_hash_create();
@@ -612,9 +613,9 @@ static void handle_eth_packet(unsigned char* args, const struct pcap_pkthdr* pkt
  */
 static void handle_radiotap_packet(unsigned char* args, const struct pcap_pkthdr* pkthdr, const unsigned char* packet)
 {
-    /* 802.11 MAC header is = 30 bytes */
+    /* 802.11 MAC header is = 34 bytes (not sure if that's universally true) */
     /* We could try harder to figure out hardware direction from the MAC header */
-    handle_ip_packet((struct ip*)(packet + ((struct radiotap_header *)packet)->it_len + 30),-1);
+    handle_ip_packet((struct ip*)(packet + ((struct radiotap_header *)packet)->it_len + 34),-1);
 }