nettrace-dns and nettrace-sni

1 files changed, 14 insertions, 5 deletions

diff --git a/src/fnettrace-sni/main.c b/src/fnettrace-sni/main.c
index ea7a91548..571089e29 100644
--- a/src/fnettrace-sni/main.c
+++ b/src/fnettrace-sni/main.c
@@ -24,6 +24,8 @@
 #include <linux/if_ether.h>
 #define MAX_BUF_SIZE (64 * 1024)
 
+static char last[512] = {'\0'};
+
 // pkt - start of TLS layer
 static void print_tls(uint32_t ip_dest, unsigned char *pkt, unsigned len) {
         assert(pkt);
@@ -67,18 +69,25 @@ static void print_tls(uint32_t ip_dest, unsigned char *pkt, unsigned len) {
                 i++;
         }
 
-        if (name)
-                printf("%02d:%02d:%02d  %15s  %s\n", t->tm_hour, t->tm_min, t->tm_sec, ip, name);
+        if (name) {
+                // filter output
+                char tmp[sizeof(last)];
+                snprintf(tmp, sizeof(last), "%02d:%02d:%02d  %-15s  %s", t->tm_hour, t->tm_min, t->tm_sec, ip, name);
+                if (strcmp(tmp, last)) {
+                        printf("%s\n", tmp);
+                        strcpy(last, tmp);
+                }
+        }
         else
                 goto nosni;
         return;
 
 errout:
-        printf("%02d:%02d:%02d  %15s  Error: invalid TLS packet\n", t->tm_hour, t->tm_min, t->tm_sec, ip);
+        printf("%02d:%02d:%02d  %-15s  Error: invalid TLS packet\n", t->tm_hour, t->tm_min, t->tm_sec, ip);
         return;
 
 nosni:
-        printf("%02d:%02d:%02d  %15s  no SNI\n", t->tm_hour, t->tm_min, t->tm_sec, ip);
+        printf("%02d:%02d:%02d  %-15s  no SNI\n", t->tm_hour, t->tm_min, t->tm_sec, ip);
         return;
 }
 
@@ -131,7 +140,7 @@ static void custom_bpf(int sock) {
 }
 
 static void run_trace(void) {
-        // grab all Ethernet packets and use a custom BPF filter to get only UDP from source port 53
+        // grab all Ethernet packets and use a custom BPF filter to get TLS/SNI packets
         int s = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
         if (s < 0)
                 errExit("socket");