Merge pull request #928 from lnslbrty/added/yet-another-ndpi-integration-example

PROPOSAL: ndpiSimpleIntegration: added another integration example

2 files changed, 1086 insertions, 1 deletions

diff --git a/example/Makefile.in b/example/Makefile.in
index c82a611c8..d71ce3f01 100644
--- a/example/Makefile.in
+++ b/example/Makefile.in
@@ -18,7 +18,10 @@ libndpiReader.a: $(COMMON_SOURCES:%.c=%.o) $(LIBNDPI)
 	ar rsv libndpiReader.a $(COMMON_SOURCES:%.c=%.o)
 
 ndpiReader: libndpiReader.a $(LIBNDPI) $(EXECUTABLE_SOURCES:%.c=%.o)
-	$(CXX) $(CFLAGS) $(EXECUTABLE_SOURCES:%.c=%.o) libndpiReader.a -o $@ $(LDFLAGS)
+	$(CC) $(CFLAGS) $(EXECUTABLE_SOURCES:%.c=%.o) libndpiReader.a -o $@ $(LDFLAGS)
+
+ndpiSimpleIntegration: ndpiSimpleIntegration.o
+	$(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
 
 %.o: %.c $(HEADERS) Makefile
 	$(CC) $(CFLAGS) -c $< -o $@
diff --git a/example/ndpiSimpleIntegration.c b/example/ndpiSimpleIntegration.c
new file mode 100644
index 000000000..a7f3b6ef2
--- /dev/null
+++ b/example/ndpiSimpleIntegration.c
@@ -0,0 +1,1082 @@
+#include <arpa/inet.h>
+#include <errno.h>
+#include <linux/if_ether.h>
+#include <netinet/in.h>
+#include <ndpi_api.h>
+#include <ndpi_main.h>
+#include <ndpi_typedefs.h>
+#include <pcap/pcap.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define MAX_FLOW_ROOTS_PER_THREAD 2048
+#define MAX_IDLE_FLOWS_PER_THREAD 64
+#define TICK_RESOLUTION 1000
+#define MAX_READER_THREADS 4
+#define IDLE_SCAN_PERIOD 10000 /* msec */
+#define MAX_IDLE_TIME 300000 /* msec */
+#define INITIAL_THREAD_HASH 0x03dd018b
+
+enum nDPI_l3_type {
+    L3_IP, L3_IP6
+};
+
+struct nDPI_flow_info {
+    uint32_t flow_id;
+    unsigned long long int packets_processed;
+    uint64_t first_seen;
+    uint64_t last_seen;
+    uint64_t hashval;
+
+    enum nDPI_l3_type l3_type;
+    union {
+        struct {
+            uint32_t src;
+            uint32_t dst;
+        } v4;
+        struct {
+            uint64_t src[2];
+            uint64_t dst[2];
+        } v6;
+    } ip_tuple;
+
+    unsigned long long int total_l4_data_len;
+    uint16_t src_port;
+    uint16_t dst_port;
+
+    uint8_t is_midstream_flow:1;
+    uint8_t flow_fin_ack_seen:1;
+    uint8_t flow_ack_seen:1;
+    uint8_t detection_completed:1;
+    uint8_t tls_client_hello_seen:1;
+    uint8_t tls_server_hello_seen:1;
+    uint8_t reserved_00:2;
+    uint8_t l4_protocol;
+
+    struct ndpi_proto detected_l7_protocol;
+    struct ndpi_proto guessed_protocol;
+
+    struct ndpi_flow_struct * ndpi_flow;
+    struct ndpi_id_struct * ndpi_src;
+    struct ndpi_id_struct * ndpi_dst;
+};
+
+struct nDPI_workflow {
+    pcap_t * pcap_handle;
+
+    uint8_t error_or_eof:1;
+    uint8_t reserved_00:7;
+    uint8_t reserved_01[3];
+
+    unsigned long long int packets_captured;
+    unsigned long long int packets_processed;
+    unsigned long long int total_l4_data_len;
+    unsigned long long int detected_flow_protocols;
+
+    uint64_t last_idle_scan_time;
+    uint64_t last_time;
+
+    void ** ndpi_flows_active;
+    unsigned long long int max_active_flows;
+    unsigned long long int cur_active_flows;
+    unsigned long long int total_active_flows;
+
+    void ** ndpi_flows_idle;
+    unsigned long long int max_idle_flows;
+    unsigned long long int cur_idle_flows;
+    unsigned long long int total_idle_flows;
+
+    struct ndpi_detection_module_struct * ndpi_struct;
+};
+
+struct nDPI_reader_thread {
+    struct nDPI_workflow * workflow;
+    pthread_t thread_id;
+    int array_index;
+};
+
+static struct nDPI_reader_thread reader_threads[MAX_READER_THREADS] = {};
+static int reader_thread_count = MAX_READER_THREADS;
+static int main_thread_shutdown = 0;
+static uint32_t flow_id = 0;
+
+static void free_workflow(struct nDPI_workflow ** const workflow);
+
+static struct nDPI_workflow * init_workflow(char const * const file_or_device)
+{
+    char pcap_error_buffer[PCAP_ERRBUF_SIZE];
+    struct nDPI_workflow * workflow = (struct nDPI_workflow *)ndpi_calloc(1, sizeof(*workflow));
+
+    if (workflow == NULL) {
+        return NULL;
+    }
+
+    if (access(file_or_device, R_OK) != 0 && errno == ENOENT) {
+        workflow->pcap_handle = pcap_open_live(file_or_device, /* 1536 */ 65535, 1, 250, pcap_error_buffer);
+    } else {
+        workflow->pcap_handle = pcap_open_offline_with_tstamp_precision(file_or_device, PCAP_TSTAMP_PRECISION_MICRO,
+                                                                        pcap_error_buffer);
+    }
+
+    if (workflow->pcap_handle == NULL) {
+        fprintf(stderr, "pcap_open_live / pcap_open_offline_with_tstamp_precision: %s\n", pcap_error_buffer);
+        free_workflow(&workflow);
+        return NULL;
+    }
+
+    ndpi_init_prefs init_prefs = ndpi_no_prefs;
+    workflow->ndpi_struct = ndpi_init_detection_module(init_prefs);
+    if (workflow->ndpi_struct == NULL) {
+        free_workflow(&workflow);
+        return NULL;
+    }
+
+    workflow->total_active_flows = 0;
+    workflow->max_active_flows = MAX_FLOW_ROOTS_PER_THREAD;
+    workflow->ndpi_flows_active = (void **)ndpi_calloc(workflow->max_active_flows, sizeof(void *));
+    if (workflow->ndpi_flows_active == NULL) {
+        free_workflow(&workflow);
+        return NULL;
+    }
+
+    workflow->total_idle_flows = 0;
+    workflow->max_idle_flows = MAX_IDLE_FLOWS_PER_THREAD;
+    workflow->ndpi_flows_idle = (void **)ndpi_calloc(workflow->max_idle_flows, sizeof(void *));
+    if (workflow->ndpi_flows_idle == NULL) {
+        free_workflow(&workflow);
+        return NULL;
+    }
+
+    NDPI_PROTOCOL_BITMASK protos;
+    NDPI_BITMASK_SET_ALL(protos);
+    ndpi_set_protocol_detection_bitmask2(workflow->ndpi_struct, &protos);
+    ndpi_finalize_initalization(workflow->ndpi_struct);
+
+    return workflow;
+}
+
+static void ndpi_flow_info_freer(void * const node)
+{
+    struct nDPI_flow_info * const flow = (struct nDPI_flow_info *)node;
+
+    ndpi_free(flow->ndpi_dst);
+    ndpi_free(flow->ndpi_src);
+    ndpi_flow_free(flow->ndpi_flow);
+    ndpi_free(flow);
+}
+
+static void free_workflow(struct nDPI_workflow ** const workflow)
+{
+    struct nDPI_workflow * const w = *workflow;
+
+    if (w == NULL) {
+        return;
+    }
+
+    if (w->pcap_handle != NULL) {
+        pcap_close(w->pcap_handle);
+        w->pcap_handle = NULL;
+    }
+
+    if (w->ndpi_struct != NULL) {
+        ndpi_exit_detection_module(w->ndpi_struct);
+    }
+    for(size_t i = 0; i < w->max_active_flows; i++) {
+        ndpi_tdestroy(w->ndpi_flows_active[i], ndpi_flow_info_freer);
+    }
+    ndpi_free(w->ndpi_flows_active);
+    ndpi_free(w->ndpi_flows_idle);
+    ndpi_free(w);
+    *workflow = NULL;
+}
+
+static int setup_reader_threads(char const * const file_or_device)
+{
+    char const * file_or_default_device;
+    char pcap_error_buffer[PCAP_ERRBUF_SIZE];
+
+    if (reader_thread_count > MAX_READER_THREADS) {
+        return 1;
+    }
+
+    if (file_or_device == NULL) {
+        file_or_default_device = pcap_lookupdev(pcap_error_buffer);
+        if (file_or_default_device == NULL) {
+            fprintf(stderr, "pcap_lookupdev: %s\n", pcap_error_buffer);
+            return 1;
+        }
+    } else {
+        file_or_default_device = file_or_device;
+    }
+
+    for (int i = 0; i < reader_thread_count; ++i) {
+        reader_threads[i].workflow = init_workflow(file_or_default_device);
+        if (reader_threads[i].workflow == NULL)
+        {
+            return 1;
+        }
+    }
+
+    return 0;
+}
+
+static int ip_tuple_to_string(struct nDPI_flow_info const * const flow,
+                              char * const src_addr_str, size_t src_addr_len,
+                              char * const dst_addr_str, size_t dst_addr_len)
+{
+    switch (flow->l3_type) {
+        case L3_IP:
+            return inet_ntop(AF_INET, (struct sockaddr_in *)&flow->ip_tuple.v4.src,
+                             src_addr_str, src_addr_len) != NULL &&
+                   inet_ntop(AF_INET, (struct sockaddr_in *)&flow->ip_tuple.v4.dst,
+                             dst_addr_str, dst_addr_len) != NULL;
+        case L3_IP6:
+            return inet_ntop(AF_INET6, (struct sockaddr_in6 *)&flow->ip_tuple.v6.src[0],
+                             src_addr_str, src_addr_len) != NULL &&
+                   inet_ntop(AF_INET6, (struct sockaddr_in6 *)&flow->ip_tuple.v6.dst[0],
+                             dst_addr_str, dst_addr_len) != NULL;
+    }
+
+    return 0;
+}
+
+#ifdef VERBOSE
+static void print_packet_info(struct nDPI_reader_thread const * const reader_thread,
+                              struct pcap_pkthdr const * const header,
+                              uint32_t l4_data_len,
+                              struct nDPI_flow_info const * const flow)
+{
+    struct nDPI_workflow const * const workflow = reader_thread->workflow;
+    char src_addr_str[INET6_ADDRSTRLEN+1] = {0};
+    char dst_addr_str[INET6_ADDRSTRLEN+1] = {0};
+    char buf[256];
+    int used = 0, ret;
+
+    ret = snprintf(buf, sizeof(buf), "[%8llu, %d, %4u] %4u bytes: ",
+                   workflow->packets_captured, reader_thread->array_index,
+                   flow->flow_id, header->caplen);
+    if (ret > 0) {
+        used += ret;
+    }
+
+    if (ip_tuple_to_string(flow, src_addr_str, sizeof(src_addr_str), dst_addr_str, sizeof(dst_addr_str)) != 0) {
+        ret = snprintf(buf + used, sizeof(buf) - used, "IP[%s -> %s]", src_addr_str, dst_addr_str);
+    } else {
+        ret = snprintf(buf + used, sizeof(buf) - used, "IP[ERROR]");
+    }
+    if (ret > 0) {
+        used += ret;
+    }
+
+    switch (flow->l4_protocol) {
+        case IPPROTO_UDP:
+            ret = snprintf(buf + used, sizeof(buf) - used, " -> UDP[%u -> %u, %u bytes]",
+                           flow->src_port, flow->dst_port, l4_data_len);
+            break;
+        case IPPROTO_TCP:
+            ret = snprintf(buf + used, sizeof(buf) - used, " -> TCP[%u -> %u, %u bytes]",
+                           flow->src_port, flow->dst_port, l4_data_len);
+            break;
+        case IPPROTO_ICMP:
+            ret = snprintf(buf + used, sizeof(buf) - used, " -> ICMP");
+            break;
+        case IPPROTO_ICMPV6:
+            ret = snprintf(buf + used, sizeof(buf) - used, " -> ICMP6");
+            break;
+        case IPPROTO_HOPOPTS:
+            ret = snprintf(buf + used, sizeof(buf) - used, " -> ICMP6 Hop-By-Hop");
+            break;
+        default:
+            ret = snprintf(buf + used, sizeof(buf) - used, " -> Unknown[0x%X]", flow->l4_protocol);
+            break;
+    }
+    if (ret > 0) {
+        used += ret;
+    }
+
+    printf("%.*s\n", used, buf);
+}
+#endif
+
+static int ip_tuples_equal(struct nDPI_flow_info const * const A,
+                           struct nDPI_flow_info const * const B)
+{
+    if (A->l3_type == L3_IP && B->l3_type == L3_IP6) {
+        return A->ip_tuple.v4.src == B->ip_tuple.v4.src &&
+               A->ip_tuple.v4.dst == B->ip_tuple.v4.dst;
+    } else if (A->l3_type == L3_IP6 && B->l3_type == L3_IP6) {
+        return A->ip_tuple.v6.src[0] == B->ip_tuple.v6.src[0] &&
+               A->ip_tuple.v6.src[1] == B->ip_tuple.v6.src[1] &&
+               A->ip_tuple.v6.dst[0] == B->ip_tuple.v6.dst[0] &&
+               A->ip_tuple.v6.dst[1] == B->ip_tuple.v6.dst[1];
+    }
+    return 0;
+}
+
+static int ip_tuples_compare(struct nDPI_flow_info const * const A,
+                             struct nDPI_flow_info const * const B)
+{
+    if (A->l3_type == L3_IP && B->l3_type == L3_IP6) {
+        if (A->ip_tuple.v4.src < B->ip_tuple.v4.src ||
+            A->ip_tuple.v4.dst < B->ip_tuple.v4.dst)
+        {
+            return -1;
+        }
+        if (A->ip_tuple.v4.src > B->ip_tuple.v4.src ||
+            A->ip_tuple.v4.dst > B->ip_tuple.v4.dst)
+        {
+            return 1;
+        }
+    } else if (A->l3_type == L3_IP6 && B->l3_type == L3_IP6) {
+        if ((A->ip_tuple.v6.src[0] < B->ip_tuple.v6.src[0] &&
+             A->ip_tuple.v6.src[1] < B->ip_tuple.v6.src[1]) ||
+            (A->ip_tuple.v6.dst[0] < B->ip_tuple.v6.dst[0] &&
+             A->ip_tuple.v6.dst[1] < B->ip_tuple.v6.dst[1]))
+        {
+            return -1;
+        }
+        if ((A->ip_tuple.v6.src[0] > B->ip_tuple.v6.src[0] &&
+             A->ip_tuple.v6.src[1] > B->ip_tuple.v6.src[1]) ||
+            (A->ip_tuple.v6.dst[0] > B->ip_tuple.v6.dst[0] &&
+             A->ip_tuple.v6.dst[1] > B->ip_tuple.v6.dst[1]))
+        {
+            return 1;
+        }
+    }
+    if (A->src_port < B->src_port ||
+        A->dst_port < B->dst_port)
+    {
+        return -1;
+    } else if (A->src_port > B->src_port ||
+               A->dst_port > B->dst_port)
+    {
+        return 1;
+    }
+    return 0;
+}
+
+static void ndpi_idle_scan_walker(void const * const A, ndpi_VISIT which, int depth, void * const user_data)
+{
+    struct nDPI_workflow * const workflow = (struct nDPI_workflow *)user_data;
+    struct nDPI_flow_info * const flow = *(struct nDPI_flow_info **)A;
+
+    (void)depth;
+
+    if (workflow == NULL || flow == NULL) {
+        return;
+    }
+
+    if (workflow->cur_idle_flows == MAX_IDLE_FLOWS_PER_THREAD) {
+        return;
+    }
+
+    if (which == ndpi_preorder || which == ndpi_leaf) {
+        if ((flow->flow_fin_ack_seen == 1 && flow->flow_ack_seen == 1) ||
+            flow->last_seen + MAX_IDLE_TIME < workflow->last_time)
+        {
+            char src_addr_str[INET6_ADDRSTRLEN+1];
+            char dst_addr_str[INET6_ADDRSTRLEN+1];
+            ip_tuple_to_string(flow, src_addr_str, sizeof(src_addr_str), dst_addr_str, sizeof(dst_addr_str));
+            workflow->ndpi_flows_idle[workflow->cur_idle_flows++] = flow;
+            workflow->total_idle_flows++;
+        }
+    }
+}
+
+static int ndpi_workflow_node_cmp(void const * const A, void const * const B) {
+    struct nDPI_flow_info const * const flow_info_a = (struct nDPI_flow_info *)A;
+    struct nDPI_flow_info const * const flow_info_b = (struct nDPI_flow_info *)B;
+
+    if (flow_info_a->hashval < flow_info_b->hashval) {
+        return(-1);
+    } else if (flow_info_a->hashval > flow_info_b->hashval) {
+        return(1);
+    }
+
+    /* Flows have the same hash */
+    if (flow_info_a->l4_protocol < flow_info_b->l4_protocol) {
+        return(-1);
+    } else if (flow_info_a->l4_protocol > flow_info_b->l4_protocol) {
+        return(1);
+    }
+
+    if (ip_tuples_equal(flow_info_a, flow_info_b) != 0 &&
+        flow_info_a->src_port == flow_info_b->src_port &&
+        flow_info_a->dst_port == flow_info_b->dst_port)
+    {
+        return(0);
+    }
+
+    return ip_tuples_compare(flow_info_a, flow_info_b);
+}
+
+static void check_for_idle_flows(struct nDPI_workflow * const workflow)
+{
+    if (workflow->last_idle_scan_time + IDLE_SCAN_PERIOD < workflow->last_time) {
+        for (size_t idle_scan_index = 0; idle_scan_index < workflow->max_active_flows; ++idle_scan_index) {
+            ndpi_twalk(workflow->ndpi_flows_active[idle_scan_index], ndpi_idle_scan_walker, workflow);
+
+            while (workflow->cur_idle_flows > 0) {
+                struct nDPI_flow_info * const f =
+                    (struct nDPI_flow_info *)workflow->ndpi_flows_idle[--workflow->cur_idle_flows];
+                if (f->flow_fin_ack_seen == 1) {
+                    printf("Free fin flow with id %u\n", f->flow_id);
+                } else {
+                    printf("Free idle flow with id %u\n", f->flow_id);
+                }
+                ndpi_tdelete(f, &workflow->ndpi_flows_active[idle_scan_index],
+                             ndpi_workflow_node_cmp);
+                ndpi_flow_info_freer(f);
+                workflow->cur_active_flows--;
+            }
+        }
+
+        workflow->last_idle_scan_time = workflow->last_time;
+    }
+}
+
+static void ndpi_process_packet(uint8_t * const args,
+                                struct pcap_pkthdr const * const header,
+                                uint8_t const * const packet)
+{
+    struct nDPI_reader_thread * const reader_thread =
+        (struct nDPI_reader_thread *)args;
+    struct nDPI_workflow * workflow;
+    struct nDPI_flow_info flow = {};
+
+    size_t hashed_index;
+    void * tree_result;
+    struct nDPI_flow_info * flow_to_process;
+
+    int direction_changed = 0;
+    struct ndpi_id_struct * ndpi_src;
+    struct ndpi_id_struct * ndpi_dst;
+
+    const struct ndpi_ethhdr * ethernet;
+    const struct ndpi_iphdr * ip;
+    struct ndpi_ipv6hdr * ip6;
+
+    uint64_t time_ms;
+    const uint16_t eth_offset = 0;
+    uint16_t ip_offset;
+    uint16_t ip_size;
+
+    const uint8_t * l4_ptr = NULL;
+    uint16_t l4_len = 0;
+
+    uint16_t type;
+    int thread_index = INITIAL_THREAD_HASH; // generated with `dd if=/dev/random bs=1024 count=1 |& hd'
+
+    if (reader_thread == NULL) {
+        return;
+    }
+    workflow = reader_thread->workflow;
+
+    if (workflow == NULL) {
+        return;
+    }
+
+    workflow->packets_captured++;
+    time_ms = ((uint64_t) header->ts.tv_sec) * TICK_RESOLUTION + header->ts.tv_usec / (1000000 / TICK_RESOLUTION);
+    workflow->last_time = time_ms;
+
+    check_for_idle_flows(workflow);
+
+    /* process datalink layer */
+    switch (pcap_datalink(workflow->pcap_handle)) {
+        case DLT_NULL:
+            if (ntohl(*((uint32_t *)&packet[eth_offset])) == 0x00000002) {
+                type = ETH_P_IP;
+            } else {
+                type = ETH_P_IPV6;
+            }
+            ip_offset = 4 + eth_offset;
+            break;
+        case DLT_EN10MB:
+            if (header->len < sizeof(struct ndpi_ethhdr)) {
+                fprintf(stderr, "[%8llu, %d] Ethernet packet too short - skipping\n",
+                        workflow->packets_captured, reader_thread->array_index);
+                return;
+            }
+            ethernet = (struct ndpi_ethhdr *) &packet[eth_offset];
+            ip_offset = sizeof(struct ndpi_ethhdr) + eth_offset;
+            type = ntohs(ethernet->h_proto);
+            switch (type) {
+                case ETH_P_IP: /* IPv4 */
+                    if (header->len < sizeof(struct ndpi_ethhdr) + sizeof(struct ndpi_iphdr)) {
+                        fprintf(stderr, "[%8llu, %d] IP packet too short - skipping\n",
+                                workflow->packets_captured, reader_thread->array_index);
+                        return;
+                    }
+                    break;
+                case ETH_P_IPV6: /* IPV6 */
+                    if (header->len < sizeof(struct ndpi_ethhdr) + sizeof(struct ndpi_ipv6hdr)) {
+                        fprintf(stderr, "[%8llu, %d] IP6 packet too short - skipping\n",
+                                workflow->packets_captured, reader_thread->array_index);
+                        return;
+                    }
+                    break;
+                case ETH_P_ARP: /* ARP */
+                    return;
+                default:
+                    fprintf(stderr, "[%8llu, %d] Unknown Ethernet packet with type 0x%X - skipping\n",
+                            workflow->packets_captured, reader_thread->array_index, type);
+                    return;
+            }
+            break;
+        default:
+            fprintf(stderr, "[%8llu, %d] Captured non IP/Ethernet packet with datalink type 0x%X - skipping\n",
+                    workflow->packets_captured, reader_thread->array_index, pcap_datalink(workflow->pcap_handle));
+            return;
+    }
+
+    if (type == ETH_P_IP) {
+        ip = (struct ndpi_iphdr *)&packet[ip_offset];
+        ip6 = NULL;
+    } else if (type == ETH_P_IPV6) {
+        ip = NULL;
+        ip6 = (struct ndpi_ipv6hdr *)&packet[ip_offset];
+    } else {
+        fprintf(stderr, "[%8llu, %d] Captured non IPv4/IPv6 packet with type 0x%X - skipping\n",
+                workflow->packets_captured, reader_thread->array_index, type);
+        return;
+    }
+    ip_size = header->len - ip_offset;
+
+    if (type == ETH_P_IP && header->len >= ip_offset) {
+        if (header->caplen < header->len) {
+            fprintf(stderr, "[%8llu, %d] Captured packet size is smaller than packet size: %u < %u\n",
+                    workflow->packets_captured, reader_thread->array_index, header->caplen, header->len);
+        }
+    }
+
+    /* process layer3 e.g. IPv4 / IPv6 */
+    if (ip != NULL && ip->version == 4) {
+        if (ip_size < sizeof(*ip)) {
+            fprintf(stderr, "[%8llu, %d] Packet smaller than IP4 header length: %u < %zu\n",
+                    workflow->packets_captured, reader_thread->array_index, ip_size, sizeof(*ip));
+            return;
+        }
+
+        flow.l3_type = L3_IP;
+        if (ndpi_detection_get_l4((uint8_t*)ip, ip_size, &l4_ptr, &l4_len,
+                                  &flow.l4_protocol, NDPI_DETECTION_ONLY_IPV4) != 0)
+        {
+            fprintf(stderr, "[%8llu, %d] nDPI IPv4/L4 payload detection failed, L4 length: %zu\n",
+                    workflow->packets_captured, reader_thread->array_index, ip_size - sizeof(*ip));
+            return;
+        }
+
+        flow.ip_tuple.v4.src = ip->saddr;
+        flow.ip_tuple.v4.dst = ip->daddr;
+        uint32_t min_addr = (flow.ip_tuple.v4.src > flow.ip_tuple.v4.dst ?
+                             flow.ip_tuple.v4.dst : flow.ip_tuple.v4.src);
+        thread_index = min_addr + ip->protocol;
+    } else if (ip6 != NULL) {
+        if (ip_size < sizeof(ip6->ip6_hdr)) {
+            fprintf(stderr, "[%8llu, %d] Packet smaller than IP6 header length: %u < %zu\n",
+                    workflow->packets_captured, reader_thread->array_index, ip_size, sizeof(ip6->ip6_hdr));
+            return;
+        }
+
+        flow.l3_type = L3_IP6;
+        if (ndpi_detection_get_l4((uint8_t*)ip6, ip_size, &l4_ptr, &l4_len,
+                                  &flow.l4_protocol, NDPI_DETECTION_ONLY_IPV6) != 0)
+        {
+            fprintf(stderr, "[%8llu, %d] nDPI IPv6/L4 payload detection failed, L4 length: %zu\n",
+                    workflow->packets_captured, reader_thread->array_index, ip_size - sizeof(*ip6));
+            return;
+        }
+
+        flow.ip_tuple.v6.src[0] = ip6->ip6_src.u6_addr.u6_addr64[0];
+        flow.ip_tuple.v6.src[1] = ip6->ip6_src.u6_addr.u6_addr64[1];
+        flow.ip_tuple.v6.dst[0] = ip6->ip6_dst.u6_addr.u6_addr64[0];
+        flow.ip_tuple.v6.dst[1] = ip6->ip6_dst.u6_addr.u6_addr64[1];
+        uint64_t min_addr[2];
+        if (flow.ip_tuple.v6.src[0] > flow.ip_tuple.v6.dst[0] &&
+            flow.ip_tuple.v6.src[1] > flow.ip_tuple.v6.dst[1])
+        {
+            min_addr[0] = flow.ip_tuple.v6.dst[0];
+            min_addr[1] = flow.ip_tuple.v6.dst[0];
+        } else {
+            min_addr[0] = flow.ip_tuple.v6.src[0];
+            min_addr[1] = flow.ip_tuple.v6.src[0];
+        }
+        thread_index = min_addr[0] + min_addr[1] + ip6->ip6_hdr.ip6_un1_nxt;
+    } else {
+        fprintf(stderr, "[%8llu, %d] Non IP/IPv6 protocol detected: 0x%X\n",
+                workflow->packets_captured, reader_thread->array_index, type);
+        return;
+    }
+
+    /* process layer4 e.g. TCP / UDP */
+    if (flow.l4_protocol == IPPROTO_TCP) {
+        const struct ndpi_tcphdr * tcp;
+
+        if (header->len < (l4_ptr - packet) + sizeof(struct ndpi_tcphdr)) {
+            fprintf(stderr, "[%8llu, %d] Malformed TCP packet, packet size smaller than expected: %u < %zu\n",
+                    workflow->packets_captured, reader_thread->array_index,
+                    header->len, (l4_ptr - packet) + sizeof(struct ndpi_tcphdr));
+            return;
+        }
+        tcp = (struct ndpi_tcphdr *)l4_ptr;
+        flow.is_midstream_flow = (tcp->syn == 0 ? 1 : 0);
+        flow.flow_fin_ack_seen = (tcp->fin == 1 && tcp->ack == 1 ? 1 : 0);
+        flow.flow_ack_seen = tcp->ack;
+        flow.src_port = ntohs(tcp->source);
+        flow.dst_port = ntohs(tcp->dest);
+    } else if (flow.l4_protocol == IPPROTO_UDP) {
+        const struct ndpi_udphdr * udp;
+
+        if (header->len < (l4_ptr - packet) + sizeof(struct ndpi_udphdr)) {
+            fprintf(stderr, "[%8llu, %d] Malformed UDP packet, packet size smaller than expected: %u < %zu\n",
+                    workflow->packets_captured, reader_thread->array_index,
+                    header->len, (l4_ptr - packet) + sizeof(struct ndpi_udphdr));
+            return;
+        }
+        udp = (struct ndpi_udphdr *)l4_ptr;
+        flow.src_port = ntohs(udp->source);
+        flow.dst_port = ntohs(udp->dest);
+    }
+
+    /* distribute flows to threads while keeping stability (same flow goes always to same thread) */
+    thread_index += (flow.src_port < flow.dst_port ? flow.dst_port : flow.src_port);
+    thread_index %= reader_thread_count;
+    if (thread_index != reader_thread->array_index) {
+        return;
+    }
+    workflow->packets_processed++;
+    workflow->total_l4_data_len += l4_len;
+
+#ifdef VERBOSE
+    print_packet_info(reader_thread, header, l4_data_len, &flow);
+#endif
+
+    /* calculate flow hash for btree find, search(insert) */
+    if (flow.l3_type == L3_IP) {
+        if (ndpi_flowv4_flow_hash(flow.l4_protocol, flow.ip_tuple.v4.src, flow.ip_tuple.v4.dst,
+                                  flow.src_port, flow.dst_port, 0, 0,
+                                  (uint8_t *)&flow.hashval, sizeof(flow.hashval)) != 0)
+        {
+            flow.hashval = flow.ip_tuple.v4.src + flow.ip_tuple.v4.dst; // fallback
+        }
+    } else if (flow.l3_type == L3_IP6) {
+        if (ndpi_flowv6_flow_hash(flow.l4_protocol, &ip6->ip6_src, &ip6->ip6_dst,
+                                  flow.src_port, flow.dst_port, 0, 0,
+                                  (uint8_t *)&flow.hashval, sizeof(flow.hashval)) != 0)
+        {
+            flow.hashval = flow.ip_tuple.v6.src[0] + flow.ip_tuple.v6.src[1];
+            flow.hashval += flow.ip_tuple.v6.dst[0] + flow.ip_tuple.v6.dst[1];
+        }
+    }
+    flow.hashval += flow.l4_protocol + flow.src_port + flow.dst_port;
+
+    hashed_index = flow.hashval % workflow->max_active_flows;
+    tree_result = ndpi_tfind(&flow, &workflow->ndpi_flows_active[hashed_index], ndpi_workflow_node_cmp);
+    if (tree_result == NULL) {
+        /* flow not found in btree: switch src <-> dst and try to find it again */
+        uint64_t orig_src_ip[2] = { flow.ip_tuple.v6.src[0], flow.ip_tuple.v6.src[1] };
+        uint64_t orig_dst_ip[2] = { flow.ip_tuple.v6.dst[0], flow.ip_tuple.v6.dst[1] };
+        uint16_t orig_src_port = flow.src_port;
+        uint16_t orig_dst_port = flow.dst_port;
+
+        flow.ip_tuple.v6.src[0] = orig_dst_ip[0];
+        flow.ip_tuple.v6.src[1] = orig_dst_ip[1];
+        flow.ip_tuple.v6.dst[0] = orig_src_ip[0];
+        flow.ip_tuple.v6.dst[1] = orig_src_ip[1];
+        flow.src_port = orig_dst_port;
+        flow.dst_port = orig_src_port;
+
+        tree_result = ndpi_tfind(&flow, &workflow->ndpi_flows_active[hashed_index], ndpi_workflow_node_cmp);
+        if (tree_result != NULL) {
+            direction_changed = 1;
+        }
+
+        flow.ip_tuple.v6.src[0] = orig_src_ip[0];
+        flow.ip_tuple.v6.src[1] = orig_src_ip[1];
+        flow.ip_tuple.v6.dst[0] = orig_dst_ip[0];
+        flow.ip_tuple.v6.dst[1] = orig_dst_ip[1];
+        flow.src_port = orig_src_port;
+        flow.dst_port = orig_dst_port;
+    }
+
+    if (tree_result == NULL) {
+        /* flow still not found, must be new */
+        if (workflow->cur_active_flows == workflow->max_active_flows) {
+            fprintf(stderr, "[%8llu, %d] max flows to track reached: %llu, idle: %llu\n",
+                    workflow->packets_captured, reader_thread->array_index,
+                    workflow->max_active_flows, workflow->cur_idle_flows);
+            return;
+        }
+
+        flow_to_process = (struct nDPI_flow_info *)ndpi_malloc(sizeof(*flow_to_process));
+        if (flow_to_process == NULL) {
+            fprintf(stderr, "[%8llu, %d] Not enough memory for flow info\n",
+                    workflow->packets_captured, reader_thread->array_index);
+            return;
+        }
+
+        workflow->cur_active_flows++;
+        workflow->total_active_flows++;
+        memcpy(flow_to_process, &flow, sizeof(*flow_to_process));
+        flow_to_process->flow_id = flow_id++;
+
+        flow_to_process->ndpi_flow = (struct ndpi_flow_struct *)ndpi_flow_malloc(SIZEOF_FLOW_STRUCT);
+        if (flow_to_process->ndpi_flow == NULL) {
+            fprintf(stderr, "[%8llu, %d, %4u] Not enough memory for flow struct\n",
+                    workflow->packets_captured, reader_thread->array_index, flow_to_process->flow_id);
+            return;
+        }
+        memset(flow_to_process->ndpi_flow, 0, SIZEOF_FLOW_STRUCT);
+
+        flow_to_process->ndpi_src = (struct ndpi_id_struct *)ndpi_calloc(1, SIZEOF_ID_STRUCT);
+        if (flow_to_process->ndpi_src == NULL) {
+            fprintf(stderr, "[%8llu, %d, %4u] Not enough memory for src id struct\n",
+                    workflow->packets_captured, reader_thread->array_index, flow_to_process->flow_id);
+            return;
+        }
+
+        flow_to_process->ndpi_dst = (struct ndpi_id_struct *)ndpi_calloc(1, SIZEOF_ID_STRUCT);
+        if (flow_to_process->ndpi_dst == NULL) {
+            fprintf(stderr, "[%8llu, %d, %4u] Not enough memory for dst id struct\n",
+                    workflow->packets_captured, reader_thread->array_index, flow_to_process->flow_id);
+            return;
+        }
+
+        printf("[%8llu, %d, %4u] new %sflow\n", workflow->packets_captured, thread_index,
+               flow_to_process->flow_id,
+               (flow_to_process->is_midstream_flow != 0 ? "midstream-" : ""));
+        if (ndpi_tsearch(flow_to_process, &workflow->ndpi_flows_active[hashed_index], ndpi_workflow_node_cmp) == NULL) {
+            /* Possible Leak, but should not happen as we'd abort earlier. */
+            return;
+        }
+
+        ndpi_src = flow_to_process->ndpi_src;
+        ndpi_dst = flow_to_process->ndpi_dst;
+    } else {
+        flow_to_process = *(struct nDPI_flow_info **)tree_result;
+
+        if (direction_changed != 0) {
+            ndpi_src = flow_to_process->ndpi_dst;
+            ndpi_dst = flow_to_process->ndpi_src;
+        } else {
+            ndpi_src = flow_to_process->ndpi_src;
+            ndpi_dst = flow_to_process->ndpi_dst;
+        }
+    }
+
+    flow_to_process->packets_processed++;
+    flow_to_process->total_l4_data_len += l4_len;
+    /* update timestamps, important for timeout handling */
+    if (flow_to_process->first_seen == 0) {
+        flow_to_process->first_seen = time_ms;
+    }
+    flow_to_process->last_seen = time_ms;
+    /* current packet is an TCP-ACK? */
+    flow_to_process->flow_ack_seen = flow.flow_ack_seen;
+
+    /* TCP-FIN: indicates that at least one side wants to end the connection */
+    if (flow.flow_fin_ack_seen != 0 && flow_to_process->flow_fin_ack_seen == 0) {
+        flow_to_process->flow_fin_ack_seen = 1;
+        printf("[%8llu, %d, %4u] end of flow\n",  workflow->packets_captured, thread_index,
+                flow_to_process->flow_id);
+        return;
+    }
+
+    /*
+     * This example tries to use maximum supported packets for detection:
+     * for uint8: 0xFF
+     */
+    if (flow_to_process->ndpi_flow->num_processed_pkts == 0xFF) {
+        return;
+    } else if (flow_to_process->ndpi_flow->num_processed_pkts == 0xFE) {
+        /* last chance to guess something, better then nothing */
+        uint8_t protocol_was_guessed = 0;
+        flow_to_process->guessed_protocol =
+            ndpi_detection_giveup(workflow->ndpi_struct,
+                                  flow_to_process->ndpi_flow,
+                                  1, &protocol_was_guessed);
+        if (protocol_was_guessed != 0) {
+            printf("[%8llu, %d, %4d][GUESSED] protocol: %s | app protocol: %s | category: %s\n",
+                    workflow->packets_captured,
+                    reader_thread->array_index,
+                    flow_to_process->flow_id,
+                    ndpi_get_proto_name(workflow->ndpi_struct, flow_to_process->guessed_protocol.master_protocol),
+                    ndpi_get_proto_name(workflow->ndpi_struct, flow_to_process->guessed_protocol.app_protocol),
+                    ndpi_category_get_name(workflow->ndpi_struct, flow_to_process->guessed_protocol.category));
+        } else {
+            printf("[%8llu, %d, %4d][FLOW NOT CLASSIFIED]\n",
+                    workflow->packets_captured, reader_thread->array_index, flow_to_process->flow_id);
+        }
+    }
+
+    flow_to_process->detected_l7_protocol =
+        ndpi_detection_process_packet(workflow->ndpi_struct, flow_to_process->ndpi_flow,
+                                      ip != NULL ? (uint8_t *)ip : (uint8_t *)ip6,
+                                      ip_size, time_ms, ndpi_src, ndpi_dst);
+
+    if (ndpi_is_protocol_detected(workflow->ndpi_struct,
+                                  flow_to_process->detected_l7_protocol) != 0 &&
+        flow_to_process->detection_completed == 0)
+    {
+        if (flow_to_process->detected_l7_protocol.master_protocol != NDPI_PROTOCOL_UNKNOWN ||
+            flow_to_process->detected_l7_protocol.app_protocol != NDPI_PROTOCOL_UNKNOWN) {
+            flow_to_process->detection_completed = 1;
+            workflow->detected_flow_protocols++;
+            printf("[%8llu, %d, %4d][DETECTED] protocol: %s | app protocol: %s | category: %s\n",
+                    workflow->packets_captured,
+                    reader_thread->array_index,
+                    flow_to_process->flow_id,
+                    ndpi_get_proto_name(workflow->ndpi_struct, flow_to_process->detected_l7_protocol.master_protocol),
+                    ndpi_get_proto_name(workflow->ndpi_struct, flow_to_process->detected_l7_protocol.app_protocol),
+                    ndpi_category_get_name(workflow->ndpi_struct, flow_to_process->detected_l7_protocol.category));
+        }
+    }
+
+    if (flow_to_process->ndpi_flow->num_extra_packets_checked <
+        flow_to_process->ndpi_flow->max_extra_packets_to_check)
+    {
+        /*
+         * Your business logic starts here.
+         *
+         * This example does print some information about
+         * TLS client and server hellos if available.
+         *
+         * You could also use nDPI's built-in json serialization
+         * and send it to a high-level application for further processing.
+         *
+         * EoE - End of Example
+         */
+
+        if (flow_to_process->detected_l7_protocol.master_protocol == NDPI_PROTOCOL_TLS ||
+            flow_to_process->detected_l7_protocol.app_protocol == NDPI_PROTOCOL_TLS)
+        {
+            if (flow_to_process->tls_client_hello_seen == 0 &&
+                flow_to_process->ndpi_flow->l4.tcp.tls.hello_processed != 0)
+            {
+                uint8_t unknown_tls_version = 0;
+                printf("[%8llu, %d, %4d][TLS-CLIENT-HELLO] version: %s | sni: %s | alpn: %s\n",
+                        workflow->packets_captured,
+                        reader_thread->array_index,
+                        flow_to_process->flow_id,
+                        ndpi_ssl_version2str(flow_to_process->ndpi_flow->protos.stun_ssl.ssl.ssl_version,
+                                             &unknown_tls_version),
+                        flow_to_process->ndpi_flow->protos.stun_ssl.ssl.client_requested_server_name,
+                        (flow_to_process->ndpi_flow->protos.stun_ssl.ssl.alpn != NULL ?
+                         flow_to_process->ndpi_flow->protos.stun_ssl.ssl.alpn : "-"));
+                flow_to_process->tls_client_hello_seen = 1;
+            }
+            if (flow_to_process->tls_server_hello_seen == 0 &&
+                flow_to_process->ndpi_flow->l4.tcp.tls.certificate_processed != 0)
+            {
+                uint8_t unknown_tls_version = 0;
+                printf("[%8llu, %d, %4d][TLS-SERVER-HELLO] version: %s | common-name(s): %.*s | "
+                                                           "issuer: %s | subject: %s\n",
+                        workflow->packets_captured,
+                        reader_thread->array_index,
+                        flow_to_process->flow_id,
+                        ndpi_ssl_version2str(flow_to_process->ndpi_flow->protos.stun_ssl.ssl.ssl_version,
+                                             &unknown_tls_version),
+                        flow_to_process->ndpi_flow->protos.stun_ssl.ssl.server_names_len,
+                        flow_to_process->ndpi_flow->protos.stun_ssl.ssl.server_names,
+                        (flow_to_process->ndpi_flow->protos.stun_ssl.ssl.issuerDN != NULL ?
+                         flow_to_process->ndpi_flow->protos.stun_ssl.ssl.issuerDN : "-"),
+                        (flow_to_process->ndpi_flow->protos.stun_ssl.ssl.subjectDN != NULL ?
+                         flow_to_process->ndpi_flow->protos.stun_ssl.ssl.subjectDN : "-"));
+                flow_to_process->tls_server_hello_seen = 1;
+            }
+        }
+    }
+}
+
+static void run_pcap_loop(struct nDPI_reader_thread const * const reader_thread)
+{
+    if (reader_thread->workflow != NULL &&
+        reader_thread->workflow->pcap_handle != NULL) {
+
+        if (pcap_loop(reader_thread->workflow->pcap_handle, -1,
+            &ndpi_process_packet, (uint8_t *)reader_thread) == PCAP_ERROR) {
+
+            fprintf(stderr, "Error while reading pcap file: '%s'\n",
+                    pcap_geterr(reader_thread->workflow->pcap_handle));
+            reader_thread->workflow->error_or_eof = 1;
+        }
+    }
+}
+
+static void break_pcap_loop(struct nDPI_reader_thread * const reader_thread)
+{
+    if (reader_thread->workflow != NULL &&
+        reader_thread->workflow->pcap_handle != NULL)
+    {
+        pcap_breakloop(reader_thread->workflow->pcap_handle);
+    }
+}
+
+static void * processing_thread(void * const ndpi_thread_arg)
+{
+    struct nDPI_reader_thread const * const reader_thread =
+        (struct nDPI_reader_thread *)ndpi_thread_arg;
+
+    printf("Starting ThreadID %d\n", reader_thread->array_index);
+    run_pcap_loop(reader_thread);
+    reader_thread->workflow->error_or_eof = 1;
+    return NULL;
+}
+
+static int processing_threads_error_or_eof(void)
+{
+    for (int i = 0; i < reader_thread_count; ++i) {
+        if (reader_threads[i].workflow->error_or_eof == 0) {
+            return 0;
+        }
+    }
+    return 1;
+}
+
+static int start_reader_threads(void)
+{
+    sigset_t thread_signal_set, old_signal_set;
+
+    sigfillset(&thread_signal_set);
+    sigdelset(&thread_signal_set, SIGINT);
+    sigdelset(&thread_signal_set, SIGTERM);
+    if (pthread_sigmask(SIG_BLOCK, &thread_signal_set, &old_signal_set) != 0) {
+        fprintf(stderr, "pthread_sigmask: %s\n", strerror(errno));
+        return 1;
+    }
+
+    for (int i = 0; i < reader_thread_count; ++i) {
+        reader_threads[i].array_index = i;
+
+        if (reader_threads[i].workflow == NULL) {
+            /* no more threads should be started */
+            break;
+        }
+
+        if (pthread_create(&reader_threads[i].thread_id, NULL,
+            processing_thread, &reader_threads[i]) != 0)
+        {
+            fprintf(stderr, "pthread_create: %s\n", strerror(errno));
+            return 1;
+        }
+    }
+
+    if (pthread_sigmask(SIG_BLOCK, &old_signal_set, NULL) != 0) {
+        fprintf(stderr, "pthread_sigmask: %s\n", strerror(errno));
+        return 1;
+    }
+
+    return 0;
+}
+
+static int stop_reader_threads(void)
+{
+    unsigned long long int total_packets_processed = 0;
+    unsigned long long int total_l4_data_len = 0;
+    unsigned long long int total_flows_captured = 0;
+    unsigned long long int total_flows_idle = 0;
+    unsigned long long int total_flows_detected = 0;
+
+    for (int i = 0; i < reader_thread_count; ++i) {
+        break_pcap_loop(&reader_threads[i]);
+    }
+
+    printf("------------------------------------ Stopping reader threads\n");
+
+    for (int i = 0; i < reader_thread_count; ++i) {
+        if (reader_threads[i].workflow == NULL) {
+            continue;
+        }
+
+        total_packets_processed += reader_threads[i].workflow->packets_processed;
+        total_l4_data_len += reader_threads[i].workflow->total_l4_data_len;
+        total_flows_captured += reader_threads[i].workflow->total_active_flows;
+        total_flows_idle += reader_threads[i].workflow->total_idle_flows;
+        total_flows_detected += reader_threads[i].workflow->detected_flow_protocols;
+
+        printf("Stopping Thread %d, processed %10llu packets, %12llu bytes, total flows: %8llu, "
+                                                     "idle flows: %8llu, detected flows: %8llu\n",
+               reader_threads[i].array_index, reader_threads[i].workflow->packets_processed,
+               reader_threads[i].workflow->total_l4_data_len, reader_threads[i].workflow->total_active_flows,
+               reader_threads[i].workflow->total_idle_flows, reader_threads[i].workflow->detected_flow_protocols);
+    }
+    /* total packets captured: same value for all threads as packet2thread distribution happens later */
+    printf("Total packets captured.: %llu\n",
+           reader_threads[0].workflow->packets_captured);
+    printf("Total packets processed: %llu\n", total_packets_processed);
+    printf("Total layer4 data size.: %llu\n", total_l4_data_len);
+    printf("Total flows captured...: %llu\n", total_flows_captured);
+    printf("Total flows timed out..: %llu\n", total_flows_idle);
+    printf("Total flows detected...: %llu\n", total_flows_detected);
+
+    for (int i = 0; i < reader_thread_count; ++i) {
+        if (reader_threads[i].workflow == NULL) {
+            continue;
+        }
+
+        if (pthread_join(reader_threads[i].thread_id, NULL) != 0) {
+            fprintf(stderr, "pthread_join: %s\n", strerror(errno));
+        }
+
+        free_workflow(&reader_threads[i].workflow);
+    }
+
+    return 0;
+}
+
+static void sighandler(int signum)
+{
+    fprintf(stderr, "Received SIGNAL %d\n", signum);
+
+    if (main_thread_shutdown == 0) {
+        main_thread_shutdown = 1;
+        if (stop_reader_threads() != 0) {
+            fprintf(stderr, "Failed to stop reader threads!\n");
+            exit(EXIT_FAILURE);
+        }
+    } else {
+        fprintf(stderr, "Reader threads are already shutting down, please be patient.\n");
+    }
+}
+
+int main(int argc, char ** argv)
+{
+    if (argc == 0) {
+        return 1;
+    }
+
+    printf("usage: %s [PCAP-FILE-OR-INTERFACE]\n"
+           "----------------------------------\n"
+           "nDPI version: %s\n"
+           " API version: %u\n"
+           "----------------------------------\n",
+           argv[0],
+           ndpi_revision(), ndpi_get_api_version());
+
+    if (setup_reader_threads((argc >= 2 ? argv[1] : NULL)) != 0) {
+        fprintf(stderr, "%s: setup_reader_threads failed\n", argv[0]);
+        return 1;
+    }
+
+    if (start_reader_threads() != 0) {
+        fprintf(stderr, "%s: start_reader_threads\n", argv[0]);
+        return 1;
+    }
+
+    signal(SIGINT, sighandler);
+    signal(SIGTERM, sighandler);
+    while (main_thread_shutdown == 0 && processing_threads_error_or_eof() == 0) {
+        sleep(1);
+    }
+
+    if (main_thread_shutdown == 0 && stop_reader_threads() != 0) {
+        fprintf(stderr, "%s: stop_reader_threads\n", argv[0]);
+        return 1;
+    }
+
+    return 0;
+}