In flight connection pool cleaning

base/pcap-snoop.c

@@ -87,6 +87,13 @@ RETSIGTYPE sig_handler PROTO_LIST((void));
 void pcap_cb PROTO_LIST((u_char *ptr,struct pcap_pkthdr *hdr,u_char *data));
 int main PROTO_LIST((int argc,char **argv));
 
+int packet_cnt = 0;  // Packet counter used for connection pool cleaning
+int conn_freq = 100; // Number of packets after which a connection pool
+                     // cleaning is performed
+int conn_ttl = 100;  // TTL of inactive connections in connection pool
+struct timeval last_packet_seen_time; // Timestamp of the last packet of the
+                                      // last block of conn_freq packets seen
+
 int err_exit(str,num)
   char *str;
   int num;
@@ -128,7 +135,7 @@ void pcap_cb(ptr,hdr,data)
     n_handler *n;
     int len;
     struct ether_header *e_hdr=(struct ether_header *)data;
-    int type;
+    int type, cleaned_conn;
     
     n=(n_handler *)ptr;
     if(hdr->caplen!=hdr->len) err_exit("Length mismatch",-1);
@@ -231,6 +238,15 @@ void pcap_cb(ptr,hdr,data)
 #endif
     }
     network_process_packet(n,&hdr->ts,data,len);
+
+    if(packet_cnt == conn_freq) {
+        packet_cnt = 0;
+        memcpy(&last_packet_seen_time,&hdr->ts,sizeof(struct timeval));
+        if(cleaned_conn = clean_old_conn())
+            printf("%d inactive connection(s) cleaned from connection pool\n", cleaned_conn);
+    } else {
+        packet_cnt++;
+    }
   }
 
 typedef struct module_def_ {
@@ -277,7 +293,7 @@ int main(argc,argv)
 
     signal(SIGINT,sig_handler);
     
-    while((c=getopt(argc,argv,"vr:f:S:yTtai:k:p:nsAxXhHVNdqem:P"))!=EOF){
+    while((c=getopt(argc,argv,"vr:F:f:S:yTt:ai:k:p:nsAxXhHVNdqem:P"))!=EOF){
       switch(c){
         case 'v':
           print_version();
@@ -319,6 +335,12 @@ int main(argc,argv)
         case 'n':
           NET_print_flags |= NET_PRINT_NO_RESOLVE;
           break;
+    case 't':
+    conn_ttl=atoi(optarg);
+    break;
+    case 'F':
+    conn_freq=atoi(optarg);
+    break;
 	case 'm':
 	  for(m=modules;m->name!=0;m++){
 	    if(!strcmp(m->name,optarg)){
@@ -428,6 +450,7 @@ int main(argc,argv)
     if(NET_print_flags & NET_PRINT_TYPESET)
       printf("\n.ps\n.fi\n");
 
+    printf("Cleaning %d remaining connection(s) from connection pool\n", destroy_all_conn());
     exit(0);
   }
       

base/tcpconn.c

@@ -59,6 +59,9 @@ int conn_number=1;
 
 static conn_struct *first_conn=0;
 
+extern struct timeval last_packet_seen_time;
+extern int conn_ttl;
+
 static int zero_conn PROTO_LIST((tcp_conn *conn));
 
 static int zero_conn(conn)
@@ -163,6 +166,33 @@ int tcp_destroy_conn(conn)
     return(0);
   }
 
+int clean_old_conn() {
+    conn_struct *conn;
+    tcp_conn *tcpconn;
+    struct timeval dt;
+    int i = 0;
+
+    for(conn=first_conn;conn;conn=conn->next) {
+        i++;
+        tcpconn = &conn->conn;
+        timestamp_diff(&last_packet_seen_time, &tcpconn->last_seen_time, &dt);
+        if(dt.tv_sec > conn_ttl) {
+            tcp_destroy_conn(&(first_conn->conn));
+        }
+    }
+    return i;
+}
+
+int destroy_all_conn() {
+    conn_struct *conn;
+    int i = 0,r;
+    while(first_conn) {
+        i++;
+        tcp_destroy_conn(&first_conn->conn);
+    }
+    return i;
+}
+
 int free_tcp_segment_queue(seg)
   segment *seg;
   {

base/tcpconn.h

@@ -83,6 +83,7 @@ typedef struct tcp_conn_ {
      stream_data r2i;   /*The stream from responder to initiator*/
      
      struct timeval start_time;
+     struct timeval last_seen_time;
      proto_handler *analyzer;    /*The analyzer to call with new data*/
      struct conn_struct_ *backptr;
 } tcp_conn;

base/tcppack.c

@@ -108,6 +108,8 @@ int process_tcp_packet(handler,ctx,p)
 
     stream=direction==DIR_R2I?&conn->r2i:&conn->i2r;
 
+    memcpy(&conn->last_seen_time,&p->ts,sizeof(struct timeval));
+
     switch(conn->state){
       case TCP_STATE_SYN1:
 	if(direction != DIR_R2I)
@@ -182,6 +184,7 @@ static int new_connection(handler,ctx,p,connp)
 
     conn->state=TCP_STATE_SYN1;
     memcpy(&conn->start_time,&p->ts,sizeof(struct timeval));
+    memcpy(&conn->last_seen_time,&p->ts,sizeof(struct timeval));
     if(r=create_proto_handler(handler,ctx,&conn->analyzer,conn,&p->ts))
       ABORT(r);
     

ssldump.1

@@ -181,6 +181,12 @@ Print the TCP headers.
 .B \-v
 Display version and copyright information.
 .TP
+.B \-t
+Specify the TTL for inactive connections referenced in the connection pool (in seconds, default: 100).
+.TP
+.B \-F
+Specify the number of packets after which a connection pool cleaning is performed (in packets, default: 100).
+.TP
 .B \-x
 Print each record in hex, as well as decoding it.
 .TP