diff --git a/bin/Makefile b/bin/Makefile
new file mode 100644
index 0000000..c064bdb
--- /dev/null
+++ b/bin/Makefile
@@ -0,0 +1,8 @@
+pibs:		pibs.o
+	gcc -Wall -o pibs pibs.o -lwiretap `pkg-config --libs glib-2.0` -lpcap -lhiredis -ggdb
+pibs.o:	pibs.c
+	gcc -D HASHDEBUG=0 -Wall -c pibs.c `pkg-config --cflags glib-2.0` -I /usr/include/wireshark/wiretap -I /usr/include/wireshark/wsutil -I /usr/include/wireshark `pkg-config --libs glib-2.0` -I /usr/local/include/hiredis -ggdb
+
+clean:
+	-rm pibs
+	-rm *.o
diff --git a/bin/pibs.c b/bin/pibs.c
new file mode 100644
index 0000000..7a1e482
--- /dev/null
+++ b/bin/pibs.c
@@ -0,0 +1,468 @@
+/*
+* pibs - Passive Identification of BackScatter
+*
+* Copyright (C) 2019 Gerard Wagener
+* Copyright (C) 2019 CIRCL Computer Incident Response Center Luxembourg
+* (SMILE gie).
+*
+* This program is free software: you can redistribute it and/or modify
+* it under the terms of the GNU Affero General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+* GNU Affero General Public License for more details.
+*
+* You should have received a copy of the GNU Affero General Public License
+* along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+#include <stdio.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <assert.h>
+#include <string.h>
+#include <pcap/pcap.h>
+#include <wtap.h>
+#include <wtap-int.h>
+#include <unistd.h>
+#include <signal.h>
+#include <netinet/ip.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <errno.h>
+
+#include <hiredis/hiredis.h>
+
+//TODO test other values
+#define NBINS 1024 //Number of bins
+#define NBINITEMS 255 //Number of items per bin
+#define SZBIN 4
+#define NBINSCALE 2 // Scaling factor of the entire datastructure
+
+#define HDBG(...) if (HASHDEBUG) fprintf(stderr, __VA_ARGS__)
+
+#define ERR_ATTACH_NOT_EMPTY 11
+#define ERR_NO_SHMID_FILE 12
+
+typedef struct pibs_header_s {
+    uint8_t magic [4];
+    uint8_t version;
+    //Put some useful stuff here
+    uint32_t next_item;
+    uint32_t bin_offset;
+    uint64_t data_size;
+    uint32_t max_item;
+    uint8_t padding [3];
+} pibs_header_t;
+
+
+/* TODO This can squezed. Timestamp can be expressed on 8 bits i.e. relative
+ * minutes
+ * IP can be represented with 16 bits ipaddr = ip / bin_size
+ * Not sure if space can be saved in usual cases
+ */
+typedef struct item_s {
+    uint32_t timestamp;
+    uint32_t next_item;
+    uint32_t ipaddr;
+} item_t;
+
+/* Need to hash source IP addresses and record first seen and flags */
+typedef struct pibs_s {
+    int errno_copy;
+    int errno_pibs;
+    char *filename;
+    int should_dump_table;
+    int show_backscatter;
+    int show_stats;
+    int should_create_shm;
+    int should_attach;
+    //TODO use self contained data structure that can be easily serialized
+    //Put data structure in an entire block to easier serialize
+    uint8_t *data;
+    uint32_t next_block;
+    uint32_t next_item;
+    uint32_t bin_offset;
+    uint64_t data_size;
+    uint32_t* bin_table;
+    uint32_t max_item;
+    item_t* items;
+    int shmid;
+    char shmid_file [FILENAME_MAX];
+} pibs_t;
+
+int load_shmid_file(pibs_t* pibs)
+{
+    FILE* fp;
+    if (pibs->shmid_file[0]) {
+        fp = fopen(pibs->shmid_file,"r");
+        if (fp) {
+            //FIXME check file
+            fscanf(fp, "%d", &pibs->shmid);
+            return pibs->shmid;
+        }
+    } else {
+        pibs->errno_pibs = ERR_NO_SHMID_FILE;
+    }
+    return -1;
+}
+
+//TODO when attaching the next_item  must be recovered if results
+//of previous runs need to be increased
+int pibs_shmat(pibs_t* pibs)
+{
+    /* FIXME  init function needs to break up in two functions. One that
+     *       initializes internal pibs structures as cli options etc
+     *       a second one for describing the data itself, size of bin_table
+     *       number of items etc.
+     */
+    if (pibs->data) {
+        free(pibs->data);
+        pibs->data = NULL;
+    }
+    if (pibs->data) {
+        pibs->errno_pibs =  ERR_ATTACH_NOT_EMPTY;
+        printf("TEST Data is not null\n");
+        return -1;
+    }
+    if (!pibs->shmid_file[0]) {
+        pibs->errno_pibs = ERR_NO_SHMID_FILE;
+        return -1;
+    }
+    if (load_shmid_file(pibs) > 0) {
+            pibs->data = shmat(pibs->shmid, NULL, SHM_RND);
+        if ( (int) pibs->data == -1) {
+            pibs->errno_copy = errno;
+        } else {
+            return 1;
+        }
+    }
+    // Something did not work
+    return -1;
+}
+
+int pibs_shmget(pibs_t* pibs)
+{
+    FILE* fp;
+    pibs->shmid = shmget(IPC_PRIVATE, pibs->data_size, IPC_CREAT |  0600);
+    if (pibs->shmid < 0) {
+        pibs->errno_copy = errno;
+    }
+
+    if (pibs->shmid_file[0]){
+            fp = fopen(pibs->shmid_file, "w");
+            if (fp) {
+                fprintf(fp,"%d",pibs->shmid);
+                fclose(fp);
+            }
+            //TODO error handling
+    }
+    //TODO attach to it and bzero it
+    //setup the tables
+    return pibs->shmid;
+}
+
+/*
+ * Returns -1 if not found
+ * returns last timestamp if found
+ */
+int_fast64_t get_last_timestamp(pibs_t* pibs, uint32_t ip)
+{
+    uint32_t idx;
+    uint32_t i;
+    //TODO explore alternative hashing functions
+    //https://stackoverflow.com/questions/664014/what-integer-hash-function-are-good-that-accepts-an-integer-hash-key/12996028#12996028
+    idx = ip % NBINS;
+    HDBG("[TS] Checking for IP %x at index = %d\n", ip, idx);
+    i = pibs->bin_table[idx];
+    while (i){
+        if (pibs->items[i].ipaddr == ip) {
+            HDBG("[TS] Found item %x at position %d\n", ip , i);
+                return pibs->items[i].timestamp;
+            }
+        i = pibs->items[i].next_item;
+    }
+    HDBG("[TS] IP: %x was not found return -1\n",ip);
+    return -1;
+}
+
+void insert_ip(pibs_t* pibs, uint32_t ip, uint32_t ts)
+{
+    uint32_t idx;
+    uint32_t i;
+    uint32_t parent;
+
+    idx = ip  % NBINS;
+    HDBG("[INS] Lookup IP address %x. Hashed value: %d\n", ip, idx);
+    parent = 0;
+    if (pibs->bin_table[idx]){
+        // There is already someone in the bin
+        i = pibs->bin_table[idx];
+        HDBG("[INS] Starting searching at position %d\n", i);
+        do {
+            HDBG("[INS] Iterating items at index %d. Current position: %d.\
+                  Next position = %d\n",
+                 idx,i,pibs->items[i].next_item);
+            HDBG("[INS] Checking IP at address %p\n",&pibs->items[i]);
+            if (pibs->items[i].ipaddr == ip) {
+               HDBG("[INS] Found item %x at position %d\n", ip , i);
+               HDBG("[INS] New timestamp for ip %x is %d\n",ip,ts);
+               pibs->items[i].timestamp = ts;
+               return;
+            }
+            parent = i;
+            i = pibs->items[i].next_item;
+        } while (i != 0 );
+        HDBG("[INS] The IP %x was not found in the item list, last parent %d\n",
+              ip, parent);
+    }
+    // The IP was not found in an item list or the hashed value wsa not present
+    // in the bin table, so create a new item
+    pibs->next_item++;
+    if (pibs->next_item > pibs->max_item) {
+        printf("FIXME run out of memory. Do something better than abort\n");
+        //Go through old timestamps and keep linked list of stuff that can be
+        //reused or do kind of defragmentation
+        abort();
+    }
+    if (pibs->bin_table[idx] == 0) {
+        pibs->bin_table[idx] = pibs->next_item;
+    }
+    HDBG("[INS] Insert ip %x at position %d, parent = %d\n", ip,
+         pibs->next_item,parent);
+    pibs->items[pibs->next_item].ipaddr = ip;
+    pibs->items[pibs->next_item].timestamp = ts;
+    if (parent) {
+        pibs->items[parent].next_item = pibs->next_item;
+    }
+}
+
+void process_frame(pibs_t* pibs, wtap *wth,
+                   uint8_t *buf, size_t length)
+{
+    struct ip* ipv4;
+    uint32_t ip;
+    struct tcphdr* tcp;
+    int_fast64_t lastseen;
+
+    if (length < sizeof(struct ip)) {
+        return;
+    }
+
+
+    ipv4 =  (struct ip*)buf;
+    // Focus only on TCP packets
+    if (ipv4->ip_p != 6)
+        return;
+
+    tcp = (struct tcphdr*)(buf+sizeof(struct ip));
+
+    memcpy(&ip, &ipv4->ip_src, 4);
+    // Record only source ips where syn flag is set
+    // TODO check other connection establishment alternatives
+    if (tcp->th_flags  == 2 ){
+        insert_ip(pibs, ip, wth->rec.ts.secs);
+        return;
+    }
+
+    lastseen =  get_last_timestamp(pibs, ip);
+
+    if (lastseen > 0){
+        HDBG("IP %x %s was already seen before at %ld. Time difference %ld.\n"
+               , ip, inet_ntoa(ipv4->ip_src), lastseen, wth->rec.ts.secs-lastseen);
+        return;
+    }
+    // TODO keep these IPs in a hashtable and rank them
+    if (pibs->show_backscatter) {
+        printf("Potential backscatter. IP. %s. TCP flags: %d. Source port:%d \n",
+               inet_ntoa(ipv4->ip_src), tcp->th_flags, ntohs(tcp->th_sport));
+    }
+    //TODO relative time
+    //Purge old ips?
+}
+
+void process_file(pibs_t* pibs)
+{
+    wtap *wth;
+    int err;
+    char *errinfo;
+    gint64 data_offset;
+    int ethertype;
+    guint8 *buf;
+
+    fprintf(stderr,"Processing %s\n",pibs->filename);
+    wth = wtap_open_offline ( pibs->filename, WTAP_TYPE_AUTO, (int*)&err,
+                             (char**)&errinfo, FALSE);
+    if (wth) {
+        /* Loop over the packets and adjust the headers */
+        while (wtap_read(wth, &err, &errinfo, &data_offset)) {
+            if (wth->rec.rec_type == REC_TYPE_PACKET) {
+                if (wth->rec.tsprec == WTAP_TSPREC_USEC){
+                    if (wth->rec.rec_header.packet_header.caplen < 14) {
+                        fprintf(stderr,"Packet too small, skip\n");
+                        continue;
+                    }
+                }
+                buf = wth->rec_data->data;
+                ethertype = buf[12] << 8 | buf[13];
+                // TODO Focus on IPv4 only
+                if (ethertype == 0x0800) {
+                    process_frame(pibs, wth, buf+14, wth->rec.rec_header.packet_header.caplen -14);
+                }
+            }
+        }
+        wtap_close(wth);
+	fprintf(stderr,"[INFO] Processing of filename %s done\n",pibs->filename);
+    }else{
+        fprintf(stderr, "[ERROR] Could not open filename %s,cause=%s\n",pibs->filename,
+                wtap_strerror(err));
+    }
+}
+
+pibs_t* init(void)
+{
+    pibs_t *pibs;
+
+    wtap_init(FALSE);
+    pibs=calloc(sizeof(pibs_t),1);
+    //TODO check if size is correct
+    pibs->data_size = sizeof(pibs_header_t) + NBINSCALE * NBINS * SZBIN * NBINITEMS * sizeof(item_t);
+    pibs->data = calloc(pibs->data_size,1);
+    pibs->filename = calloc(FILENAME_MAX,1);
+    printf("#Internal look up structure size in bytes: %ld\n",  pibs->data_size);
+    // Build header
+    pibs->data[0]='P';
+    pibs->data[1] = 'I';
+    pibs->data[2] = 'B';
+    pibs->data[3] = 'S';
+    pibs->data[4] = 1; //version 1
+    pibs->next_block = sizeof(pibs_header_t);
+    pibs->bin_offset = pibs->next_block;
+    printf("#data address is %p\n",pibs->data);
+    pibs->bin_table = (uint32_t*)(pibs->data+pibs->bin_offset);
+    printf("#bin_table address is %p\n", pibs->bin_table);
+    // Create bins
+    pibs->next_block+=SZBIN * NBINS;
+    printf("#next block %d\n", pibs->next_block);
+    pibs->items = (item_t*)(pibs->data+pibs->next_block);
+    pibs->next_item = 0;
+    printf("#items are address %p\n", pibs->items);
+    pibs->max_item = NBINS * NBINITEMS;
+    printf("#max_item: %d\n", pibs->max_item);
+    return pibs;
+}
+
+void pibs_dump_raw(pibs_t* pibs)
+{
+    int i;
+    printf("#RAW table dump\n");
+    printf("#Index next_item\n");
+    printf("#BINs\n");
+    for (i=0; i< NBINS; i++) {
+        printf("%d  %d\n", i, pibs->bin_table[i]);
+    }
+    printf("#ITEMS\n");
+    printf("#Index next_item, timestamp, ipaddr\n");
+    for (i=0; i < NBINITEMS * NBINS; i++) {
+        printf("%d %d %d %x\n", i, pibs->items[i].next_item,
+                                 pibs->items[i].timestamp,
+                                 pibs->items[i].ipaddr);
+    }
+}
+
+void pibs_dump_stats(pibs_t* pibs)
+{
+    int i;
+    int j;
+    int cnt;
+    uint64_t sum;
+    sum = 0;
+    printf("#Bin table\n");
+    printf("#Bin number, Item offset, number of items\n");
+    for (i=0; i < NBINS; i++) {
+        j= pibs->bin_table[i];
+        cnt = 0;
+        while (j) {
+            cnt++;
+            j=pibs->items[j].next_item;
+        }
+        sum+=cnt;
+        printf("%d %d %d\n", i, pibs->bin_table[i], cnt);
+    }
+    printf("#Number of unique IP addresses: %ld\n", sum);
+}
+
+int main(int argc, char* argv[])
+{
+
+    int opt;
+    pibs_t* pibs;
+
+    pibs  = init();
+
+    fprintf(stderr, "[INFO] pid = %d\n",(int)getpid());
+
+    while ((opt = getopt(argc, argv, "r:dbsni:a")) != -1) {
+        switch (opt) {
+            case 'r':
+                strncpy(pibs->filename, optarg, FILENAME_MAX);
+                break;
+            case 'd':
+                pibs->should_dump_table = 1;
+                break;
+            case 'b':
+                pibs->show_backscatter = 1;
+                break;
+            case 's':
+                pibs->show_stats = 1;
+                break;
+            case 'n':
+                pibs->should_create_shm = 1;
+                break;
+            case 'i':
+                strncpy(pibs->shmid_file, optarg, FILENAME_MAX);
+                break;
+            case 'a':
+                pibs->should_attach = 1;
+                break;
+
+            default: /* '?' */
+
+                fprintf(stderr, "[ERROR] Invalid command line was specified\n");
+        }
+    }
+    if (pibs->should_create_shm) {
+        pibs_shmget(pibs);
+        if (pibs->shmid >0){
+            printf("Create a new shared memory segment %d\n", pibs->shmid);
+        } else {
+            printf("Failed to get shared memory segment. Cause = %s\n",
+                    strerror(pibs->errno_copy));
+        }
+    }
+    if (pibs->should_attach) {
+        if (pibs_shmat(pibs) > 0 ) {
+            printf("Attached to shared memory segment %d\n", pibs->shmid);
+        } else {
+            printf("Failed to attach to shared memory segment. System error:%s\n",
+                    strerror(pibs->errno_copy));
+            return EXIT_FAILURE;
+        }
+    }
+    if (pibs->filename[0]) {
+        process_file(pibs);
+    }
+    if (pibs->should_dump_table){
+        pibs_dump_raw(pibs);
+    }
+    if (pibs->show_stats){
+        pibs_dump_stats(pibs);
+    }
+    return EXIT_FAILURE;
+}