Add Waiting for multicast packet mode.

omvs_main.c

@@ -17,6 +17,7 @@ static gint _omvs_jobs = 1;
 static gint _omvs_sleep = 1000;
 static gint _omvs_timeout = 10000;
 static gboolean _omvs_quiet;
+static gboolean _omvs_wait;
 
 static gchar **_omvs_net_dev_names;
 static gchar **_omvs_net_dev_descs;
@@ -38,6 +39,8 @@ static GOptionEntry _omvs_entries[] =
     "Timeout time(milliseconds) in each scan", "ms" },
   { "quiet", 'q', 0, G_OPTION_ARG_NONE, &_omvs_quiet,
     "Print no log except for errors", NULL },
+  { "wait", 'w', 0, G_OPTION_ARG_NONE, &_omvs_wait,
+    "Wait for multicast packet", NULL },
   { NULL }
 };
 
@@ -84,6 +87,7 @@ static gint _omvs_print_net_devs_info(void);
 static gint _omvs_deinit_net_devs_info(void);
 static gint _omvs_start_scan(OMVSScanner *scanner);
 static gpointer _omvs_start_scan_job(gpointer data);
+static gint _omvs_wait_for_multicast_packet(void);
 
 static gint _omvs_init_net_devs_info(void) {
   gchar errbuf[PCAP_ERRBUF_SIZE];
@@ -198,7 +202,7 @@ static gpointer _omvs_start_scan_job(gpointer data) {
     addr[3] = (guint8)((o_ipaddr->addr >> 0) & 0xff);
 
     addr_str =
-      g_strdup_printf("%d.%d.%d.%d", addr[0], addr[1], addr[2], addr[3]);
+      g_strdup_printf("%u.%u.%u.%u", addr[0], addr[1], addr[2], addr[3]);
 
     if (!_omvs_quiet) {
       g_print("[%p] start scanning %s\n", (void *)g_thread_self(), addr_str);
@@ -392,6 +396,153 @@ static gint _omvs_start_scan(OMVSScanner *scanner) {
   return 0;
 }
 
+static gint _omvs_wait_for_multicast_packet(void) {
+  pcap_t *pcap;
+  gchar errbuf[PCAP_ERRBUF_SIZE];
+  const guint8 *packet;
+  struct pcap_pkthdr *header;
+  GHashTable *urihashtable;
+  gint64 time1, time2;
+  OMVSGst gst;
+  gchar *cur_uri;
+
+  pcap = pcap_open_live(_omvs_net_dev_names[_omvs_net_dev_idx],
+    sizeof(OMVSEthHdr) + sizeof(OMVSIPHdr) + sizeof(OMVSUDPHdr),
+    TRUE, 500, errbuf);
+  if (pcap == NULL) {
+    g_printerr("[%p] can't open pcap: %s\n", (void *)g_thread_self(), errbuf);
+    goto finish_return2;
+  }
+  if (pcap_datalink(pcap) != DLT_EN10MB) {
+    g_printerr("[%p] %s is not ethernet\n", (void *)g_thread_self(),
+      _omvs_net_dev_names[_omvs_net_dev_idx]);
+    goto finish_return3;
+  }
+
+  gst = NULL;
+  urihashtable = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, NULL);
+  time1 = g_get_monotonic_time();
+
+  for (;;) {
+    gint ret;
+    guint caplen;
+    OMVSIPHdr *ip;
+    OMVSUDPHdr *udp;
+    guint ip_hdr_len;
+    gint udp_port;
+    GInetAddress *addr;
+    gchar *addr_str;
+    guint32 haddr;
+    gchar *uri;
+    gchar *filename;
+
+    ret = pcap_next_ex(pcap, &header, &packet);
+
+    if (ret < 0) {
+      break;
+    }
+
+    if (gst) {
+      time2 = g_get_monotonic_time();
+      if (omvs_gst_is_finished(gst)) {
+        if (!_omvs_quiet) {
+          g_print("[%p] finish scanning %s\n", (void *)g_thread_self(),
+            cur_uri);
+        }
+        omvs_gst_close(gst);
+        gst = NULL;
+      } else if (time2 - time1 > (gint64)((gint64)_omvs_timeout * 1000)) {
+        if (!_omvs_quiet) {
+          g_print("[%p] finish scanning %s\n", (void *)g_thread_self(),
+            cur_uri);
+        }
+        omvs_gst_close(gst);
+        gst = NULL;
+      } else {
+        continue;
+      }
+    }
+
+    if (ret == 0) {
+      continue;
+    }
+
+    caplen = header->caplen;
+
+    if (caplen < sizeof(OMVSEthHdr)) {
+      continue;
+    }
+
+    packet += sizeof(OMVSEthHdr);
+    caplen -= sizeof(OMVSEthHdr);
+    if (caplen < sizeof(OMVSIPHdr)) {
+      continue;
+    }
+
+    ip = (OMVSIPHdr *)packet;
+    ip_hdr_len = (ip->vhl & 0x0f) * 4;
+    if (caplen < ip_hdr_len) {
+      continue;
+    }
+
+    if (ip->protocol != _OMVS_IPPROTO_UDP) {
+      continue;
+    }
+
+    addr = g_inet_address_new_from_bytes(
+      (const guint8 *)&ip->daddr, G_SOCKET_FAMILY_IPV4);
+    if (!g_inet_address_get_is_multicast(addr)) {
+      g_object_unref(addr);
+      continue;
+    }
+    g_object_unref(addr);
+
+    packet += ip_hdr_len;
+    caplen -= ip_hdr_len;
+
+    if (caplen < sizeof(OMVSUDPHdr)) {
+      continue;
+    }
+
+    udp = (OMVSUDPHdr *)packet;
+    udp_port = g_ntohs(udp->uh_dport);
+
+    haddr = g_ntohl(ip->daddr);
+    addr_str = g_strdup_printf("%u.%u.%u.%u",
+      (haddr >> 24) & 0xff,
+      (haddr >> 16) & 0xff,
+      (haddr >> 8) & 0xff,
+      (haddr >> 0) & 0xff);
+    uri = g_strdup_printf("udp://%s:%u", addr_str, udp_port);
+    filename =
+      g_strdup_printf("%s/%s-%d.png", _omvs_outdir, addr_str, udp_port);
+    g_free(addr_str);
+
+    if (!g_hash_table_insert(urihashtable, uri, NULL)) {
+      continue;
+    }
+
+    cur_uri = uri;
+    if (!_omvs_quiet) {
+      g_print("[%p] start scanning %s\n", (void *)g_thread_self(), cur_uri);
+      g_print("[%p] trying to save %s to %s\n", (void *)g_thread_self(),
+        cur_uri, filename);
+    }
+    time1 = g_get_monotonic_time();
+    g_assert(gst == NULL);
+    gst = omvs_gst_open(cur_uri, filename);
+  }
+
+  g_hash_table_destroy(urihashtable);
+
+  return 0;
+
+finish_return3:
+  pcap_close(pcap);
+finish_return2:
+  return -1;
+}
+
 int main(int argc, char *argv[]) {
   GError *error = NULL;
   GOptionContext *context;
@@ -428,7 +579,7 @@ int main(int argc, char *argv[]) {
     goto finish_return;
   }
 
-  if (argc < 2 || _omvs_net_dev_idx >= _omvs_num_net_devs) {
+  if ((!_omvs_wait && argc < 2) || _omvs_net_dev_idx >= _omvs_num_net_devs) {
     gchar *help_msg;
     help_msg = g_option_context_get_help(context, TRUE, NULL);
     g_print("%s", help_msg);
@@ -439,6 +590,11 @@ int main(int argc, char *argv[]) {
 
   g_mkdir(_omvs_outdir, 0755);
 
+  if (_omvs_wait) {
+    _omvs_wait_for_multicast_packet();
+    goto finish_return;
+  }
+
   num_ipaddrs = 0;
   for (i = 1; i < argc; i++) {
     GInetAddressMask *mask;