[media] dvb-net: split the logic at dvb_net_ule() into other functions
authorMauro Carvalho Chehab <mchehab@s-opensource.com>
Sat, 19 Nov 2016 14:56:59 +0000 (12:56 -0200)
committerMauro Carvalho Chehab <mchehab@s-opensource.com>
Fri, 25 Nov 2016 08:45:14 +0000 (06:45 -0200)
This function is too big and too complex, making really hard
to understand what's there.

Split it into sub-routines, in order to make it easier to be
understood, and to allow gcc to better parse it.

As a bonus, it gets rid of a goto in the middle of a routine.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
drivers/media/dvb-core/dvb_net.c

index 6fef0fc61cd2d015f036c5328971ebb525d0f3ad..bd833b0824c6a34e1764a1b2701966b2ab950281 100644 (file)
@@ -332,8 +332,458 @@ struct dvb_net_ule_handle {
 #endif
 };
 
+static int dvb_net_ule_new_ts_cell(struct dvb_net_ule_handle *h)
+{
+       /* We are about to process a new TS cell. */
+
+#ifdef ULE_DEBUG
+       if (h->ule_where >= &h->ule_hist[100*TS_SZ])
+               h->ule_where = h->ule_hist;
+       memcpy(h->ule_where, h->ts, TS_SZ);
+       if (h->ule_dump) {
+               hexdump(h->ule_where, TS_SZ);
+               h->ule_dump = 0;
+       }
+       h->ule_where += TS_SZ;
+#endif
+
+       /*
+        * Check TS h->error conditions: sync_byte, transport_error_indicator,
+        * scrambling_control .
+        */
+       if ((h->ts[0] != TS_SYNC) || (h->ts[1] & TS_TEI) ||
+           ((h->ts[3] & TS_SC) != 0)) {
+               pr_warn("%lu: Invalid TS cell: SYNC %#x, TEI %u, SC %#x.\n",
+                       h->priv->ts_count, h->ts[0],
+                       (h->ts[1] & TS_TEI) >> 7,
+                       (h->ts[3] & TS_SC) >> 6);
+
+               /* Drop partly decoded SNDU, reset state, resync on PUSI. */
+               if (h->priv->ule_skb) {
+                       dev_kfree_skb(h->priv->ule_skb);
+                       /* Prepare for next SNDU. */
+                       h->dev->stats.rx_errors++;
+                       h->dev->stats.rx_frame_errors++;
+               }
+               reset_ule(h->priv);
+               h->priv->need_pusi = 1;
+
+               /* Continue with next TS cell. */
+               h->ts += TS_SZ;
+               h->priv->ts_count++;
+               return 1;
+       }
+
+       h->ts_remain = 184;
+       h->from_where = h->ts + 4;
+
+       return 0;
+}
+
+static int dvb_net_ule_ts_pusi(struct dvb_net_ule_handle *h)
+{
+       if (h->ts[1] & TS_PUSI) {
+               /* Find beginning of first ULE SNDU in current TS cell. */
+               /* Synchronize continuity counter. */
+               h->priv->tscc = h->ts[3] & 0x0F;
+               /* There is a pointer field here. */
+               if (h->ts[4] > h->ts_remain) {
+                       pr_err("%lu: Invalid ULE packet (pointer field %d)\n",
+                               h->priv->ts_count, h->ts[4]);
+                       h->ts += TS_SZ;
+                       h->priv->ts_count++;
+                       return 1;
+               }
+               /* Skip to destination of pointer field. */
+               h->from_where = &h->ts[5] + h->ts[4];
+               h->ts_remain -= 1 + h->ts[4];
+               h->skipped = 0;
+       } else {
+               h->skipped++;
+               h->ts += TS_SZ;
+               h->priv->ts_count++;
+               return 1;
+       }
+
+       return 0;
+}
+
+static int dvb_net_ule_new_ts(struct dvb_net_ule_handle *h)
+{
+       /* Check continuity counter. */
+       if ((h->ts[3] & 0x0F) == h->priv->tscc)
+               h->priv->tscc = (h->priv->tscc + 1) & 0x0F;
+       else {
+               /* TS discontinuity handling: */
+               pr_warn("%lu: TS discontinuity: got %#x, expected %#x.\n",
+                       h->priv->ts_count, h->ts[3] & 0x0F,
+                       h->priv->tscc);
+               /* Drop partly decoded SNDU, reset state, resync on PUSI. */
+               if (h->priv->ule_skb) {
+                       dev_kfree_skb(h->priv->ule_skb);
+                       /* Prepare for next SNDU. */
+                       // reset_ule(h->priv);  moved to below.
+                       h->dev->stats.rx_errors++;
+                       h->dev->stats.rx_frame_errors++;
+               }
+               reset_ule(h->priv);
+               /* skip to next PUSI. */
+               h->priv->need_pusi = 1;
+               return 1;
+       }
+       /*
+        * If we still have an incomplete payload, but PUSI is
+        * set; some TS cells are missing.
+        * This is only possible here, if we missed exactly 16 TS
+        * cells (continuity counter wrap).
+        */
+       if (h->ts[1] & TS_PUSI) {
+               if (!h->priv->need_pusi) {
+                       if (!(*h->from_where < (h->ts_remain-1)) ||
+                           *h->from_where != h->priv->ule_sndu_remain) {
+                               /*
+                                * Pointer field is invalid.
+                                * Drop this TS cell and any started ULE SNDU.
+                                */
+                               pr_warn("%lu: Invalid pointer field: %u.\n",
+                                       h->priv->ts_count,
+                                       *h->from_where);
+
+                               /*
+                                * Drop partly decoded SNDU, reset state,
+                                * resync on PUSI.
+                                */
+                               if (h->priv->ule_skb) {
+                                       h->error = true;
+                                       dev_kfree_skb(h->priv->ule_skb);
+                               }
+
+                               if (h->error || h->priv->ule_sndu_remain) {
+                                       h->dev->stats.rx_errors++;
+                                       h->dev->stats.rx_frame_errors++;
+                                       h->error = false;
+                               }
+
+                               reset_ule(h->priv);
+                               h->priv->need_pusi = 1;
+                               return 1;
+                       }
+                       /*
+                        * Skip pointer field (we're processing a
+                        * packed payload).
+                        */
+                       h->from_where += 1;
+                       h->ts_remain -= 1;
+               } else
+                       h->priv->need_pusi = 0;
+
+               if (h->priv->ule_sndu_remain > 183) {
+                       /*
+                        * Current SNDU lacks more data than there
+                        * could be available in the current TS cell.
+                        */
+                       h->dev->stats.rx_errors++;
+                       h->dev->stats.rx_length_errors++;
+                       pr_warn("%lu: Expected %d more SNDU bytes, but got PUSI (pf %d, h->ts_remain %d).  Flushing incomplete payload.\n",
+                               h->priv->ts_count,
+                               h->priv->ule_sndu_remain,
+                               h->ts[4], h->ts_remain);
+                       dev_kfree_skb(h->priv->ule_skb);
+                       /* Prepare for next SNDU. */
+                       reset_ule(h->priv);
+                       /*
+                        * Resync: go to where pointer field points to:
+                        * start of next ULE SNDU.
+                        */
+                       h->from_where += h->ts[4];
+                       h->ts_remain -= h->ts[4];
+               }
+       }
+       return 0;
+}
+
+
+/*
+ * Start a new payload with skb.
+ * Find ULE header.  It is only guaranteed that the
+ * length field (2 bytes) is contained in the current
+ * TS.
+ * Check h.ts_remain has to be >= 2 here.
+ */
+static int dvb_net_ule_new_payload(struct dvb_net_ule_handle *h)
+{
+       if (h->ts_remain < 2) {
+               pr_warn("Invalid payload packing: only %d bytes left in TS.  Resyncing.\n",
+                       h->ts_remain);
+               h->priv->ule_sndu_len = 0;
+               h->priv->need_pusi = 1;
+               h->ts += TS_SZ;
+               return 1;
+       }
+
+       if (!h->priv->ule_sndu_len) {
+               /* Got at least two bytes, thus extrace the SNDU length. */
+               h->priv->ule_sndu_len = h->from_where[0] << 8 |
+                                       h->from_where[1];
+               if (h->priv->ule_sndu_len & 0x8000) {
+                       /* D-Bit is set: no dest mac present. */
+                       h->priv->ule_sndu_len &= 0x7FFF;
+                       h->priv->ule_dbit = 1;
+               } else
+                       h->priv->ule_dbit = 0;
+
+               if (h->priv->ule_sndu_len < 5) {
+                       pr_warn("%lu: Invalid ULE SNDU length %u. Resyncing.\n",
+                               h->priv->ts_count,
+                               h->priv->ule_sndu_len);
+                       h->dev->stats.rx_errors++;
+                       h->dev->stats.rx_length_errors++;
+                       h->priv->ule_sndu_len = 0;
+                       h->priv->need_pusi = 1;
+                       h->new_ts = 1;
+                       h->ts += TS_SZ;
+                       h->priv->ts_count++;
+                       return 1;
+               }
+               h->ts_remain -= 2;      /* consume the 2 bytes SNDU length. */
+               h->from_where += 2;
+       }
+
+       h->priv->ule_sndu_remain = h->priv->ule_sndu_len + 2;
+       /*
+        * State of current TS:
+        *   h->ts_remain (remaining bytes in the current TS cell)
+        *   0  ule_type is not available now, we need the next TS cell
+        *   1  the first byte of the ule_type is present
+        * >=2  full ULE header present, maybe some payload data as well.
+        */
+       switch (h->ts_remain) {
+       case 1:
+               h->priv->ule_sndu_remain--;
+               h->priv->ule_sndu_type = h->from_where[0] << 8;
+
+               /* first byte of ule_type is set. */
+               h->priv->ule_sndu_type_1 = 1;
+               h->ts_remain -= 1;
+               h->from_where += 1;
+               /* fallthrough */
+       case 0:
+               h->new_ts = 1;
+               h->ts += TS_SZ;
+               h->priv->ts_count++;
+               return 1;
+
+       default: /* complete ULE header is present in current TS. */
+               /* Extract ULE type field. */
+               if (h->priv->ule_sndu_type_1) {
+                       h->priv->ule_sndu_type_1 = 0;
+                       h->priv->ule_sndu_type |= h->from_where[0];
+                       h->from_where += 1; /* points to payload start. */
+                       h->ts_remain -= 1;
+               } else {
+                       /* Complete type is present in new TS. */
+                       h->priv->ule_sndu_type = h->from_where[0] << 8 |
+                                                h->from_where[1];
+                       h->from_where += 2; /* points to payload start. */
+                       h->ts_remain -= 2;
+               }
+               break;
+       }
+
+       /*
+        * Allocate the skb (decoder target buffer) with the correct size,
+        * as follows:
+        *
+        * prepare for the largest case: bridged SNDU with MAC address
+        * (dbit = 0).
+        */
+       h->priv->ule_skb = dev_alloc_skb(h->priv->ule_sndu_len +
+                                        ETH_HLEN + ETH_ALEN);
+       if (!h->priv->ule_skb) {
+               pr_notice("%s: Memory squeeze, dropping packet.\n",
+                         h->dev->name);
+               h->dev->stats.rx_dropped++;
+               return -1;
+       }
+
+       /* This includes the CRC32 _and_ dest mac, if !dbit. */
+       h->priv->ule_sndu_remain = h->priv->ule_sndu_len;
+       h->priv->ule_skb->dev = h->dev;
+       /*
+        * Leave space for Ethernet or bridged SNDU header
+        * (eth hdr plus one MAC addr).
+        */
+       skb_reserve(h->priv->ule_skb, ETH_HLEN + ETH_ALEN);
+
+       return 0;
+}
+
+
+static int dvb_net_ule_should_drop(struct dvb_net_ule_handle *h)
+{
+       static const u8 bc_addr[ETH_ALEN] = { [0 ... ETH_ALEN - 1] = 0xff };
+
+       /*
+        * The destination MAC address is the next data in the skb.  It comes
+        * before any extension headers.
+        *
+        * Check if the payload of this SNDU should be passed up the stack.
+        */
+       if (h->priv->rx_mode == RX_MODE_PROMISC)
+               return 0;
+
+       if (h->priv->ule_skb->data[0] & 0x01) {
+               /* multicast or broadcast */
+               if (!ether_addr_equal(h->priv->ule_skb->data, bc_addr)) {
+                       /* multicast */
+                       if (h->priv->rx_mode == RX_MODE_MULTI) {
+                               int i;
+
+                               for (i = 0; i < h->priv->multi_num &&
+                                    !ether_addr_equal(h->priv->ule_skb->data,
+                                                      h->priv->multi_macs[i]);
+                                    i++)
+                                       ;
+                               if (i == h->priv->multi_num)
+                                       return 1;
+                       } else if (h->priv->rx_mode != RX_MODE_ALL_MULTI)
+                               return 1; /* no broadcast; */
+                       /*
+                        * else:
+                        * all multicast mode: accept all multicast packets
+                        */
+               }
+               /* else: broadcast */
+       } else if (!ether_addr_equal(h->priv->ule_skb->data, h->dev->dev_addr))
+               return 1;
+
+       return 0;
+}
+
+
+static void dvb_net_ule_check_crc(struct dvb_net_ule_handle *h,
+                                 u32 ule_crc, u32 expected_crc)
+{
+       u8 dest_addr[ETH_ALEN];
+
+       if (ule_crc != expected_crc) {
+               pr_warn("%lu: CRC32 check FAILED: %08x / %08x, SNDU len %d type %#x, ts_remain %d, next 2: %x.\n",
+                       h->priv->ts_count, ule_crc, expected_crc,
+                       h->priv->ule_sndu_len, h->priv->ule_sndu_type,
+                       h->ts_remain,
+                       h->ts_remain > 2 ?
+                               *(unsigned short *)h->from_where : 0);
+
+       #ifdef ULE_DEBUG
+               hexdump(iov[0].iov_base, iov[0].iov_len);
+               hexdump(iov[1].iov_base, iov[1].iov_len);
+               hexdump(iov[2].iov_base, iov[2].iov_len);
+
+               if (h->ule_where == h->ule_hist) {
+                       hexdump(&h->ule_hist[98*TS_SZ], TS_SZ);
+                       hexdump(&h->ule_hist[99*TS_SZ], TS_SZ);
+               } else if (h->ule_where == &h->ule_hist[TS_SZ]) {
+                       hexdump(&h->ule_hist[99*TS_SZ], TS_SZ);
+                       hexdump(h->ule_hist, TS_SZ);
+               } else {
+                       hexdump(h->ule_where - TS_SZ - TS_SZ, TS_SZ);
+                       hexdump(h->ule_where - TS_SZ, TS_SZ);
+               }
+               h->ule_dump = 1;
+       #endif
+
+               h->dev->stats.rx_errors++;
+               h->dev->stats.rx_crc_errors++;
+               dev_kfree_skb(h->priv->ule_skb);
+
+               return;
+       }
+
+       /* CRC32 verified OK. */
+
+       /* CRC32 was OK, so remove it from skb. */
+       h->priv->ule_skb->tail -= 4;
+       h->priv->ule_skb->len -= 4;
+
+       if (!h->priv->ule_dbit) {
+               if (dvb_net_ule_should_drop(h)) {
+#ifdef ULE_DEBUG
+                       netdev_dbg(h->dev,
+                                  "Dropping SNDU: MAC destination address does not match: dest addr: %pM, h->dev addr: %pM\n",
+                                  h->priv->ule_skb->data, h->dev->dev_addr);
+#endif
+                       dev_kfree_skb(h->priv->ule_skb);
+                       return;
+               }
+
+               skb_copy_from_linear_data(h->priv->ule_skb, dest_addr,
+                                         ETH_ALEN);
+               skb_pull(h->priv->ule_skb, ETH_ALEN);
+       }
+
+       /* Handle ULE Extension Headers. */
+       if (h->priv->ule_sndu_type < ETH_P_802_3_MIN) {
+               /* There is an extension header.  Handle it accordingly. */
+               int l = handle_ule_extensions(h->priv);
+
+               if (l < 0) {
+                       /*
+                        * Mandatory extension header unknown or TEST SNDU.
+                        * Drop it.
+                        */
+
+                       // pr_warn("Dropping SNDU, extension headers.\n" );
+                       dev_kfree_skb(h->priv->ule_skb);
+                       return;
+               }
+               skb_pull(h->priv->ule_skb, l);
+       }
+
+       /*
+        * Construct/assure correct ethernet header.
+        * Note: in bridged mode (h->priv->ule_bridged != 0)
+        * we already have the (original) ethernet
+        * header at the start of the payload (after
+        * optional dest. address and any extension
+        * headers).
+        */
+       if (!h->priv->ule_bridged) {
+               skb_push(h->priv->ule_skb, ETH_HLEN);
+               h->ethh = (struct ethhdr *)h->priv->ule_skb->data;
+               if (!h->priv->ule_dbit) {
+                       /*
+                        * dest_addr buffer is only valid if
+                        * h->priv->ule_dbit == 0
+                        */
+                       memcpy(h->ethh->h_dest, dest_addr, ETH_ALEN);
+                       eth_zero_addr(h->ethh->h_source);
+               } else /* zeroize source and dest */
+                       memset(h->ethh, 0, ETH_ALEN * 2);
+
+               h->ethh->h_proto = htons(h->priv->ule_sndu_type);
+       }
+       /* else:  skb is in correct state; nothing to do. */
+       h->priv->ule_bridged = 0;
+
+       /* Stuff into kernel's protocol stack. */
+       h->priv->ule_skb->protocol = dvb_net_eth_type_trans(h->priv->ule_skb,
+                                                          h->dev);
+       /*
+        * If D-bit is set (i.e. destination MAC address not present),
+        * receive the packet anyhow.
+        */
+#if 0
+       if (h->priv->ule_dbit && skb->pkt_type == PACKET_OTHERHOST)
+               h->priv->ule_skb->pkt_type = PACKET_HOST;
+#endif
+       h->dev->stats.rx_packets++;
+       h->dev->stats.rx_bytes += h->priv->ule_skb->len;
+       netif_rx(h->priv->ule_skb);
+}
+
 static void dvb_net_ule(struct net_device *dev, const u8 *buf, size_t buf_len)
 {
+       int ret;
        struct dvb_net_ule_handle h = {
                .dev = dev,
                .buf = buf,
@@ -352,251 +802,42 @@ static void dvb_net_ule(struct net_device *dev, const u8 *buf, size_t buf_len)
 #endif
        };
 
-       /* For all TS cells in current buffer.
+       /*
+        * For all TS cells in current buffer.
         * Appearently, we are called for every single TS cell.
         */
-       for (h.ts = h.buf, h.ts_end = h.buf + h.buf_len; h.ts < h.ts_end; /* no incr. */ ) {
+       for (h.ts = h.buf, h.ts_end = h.buf + h.buf_len;
+            h.ts < h.ts_end; /* no incr. */) {
                if (h.new_ts) {
                        /* We are about to process a new TS cell. */
-
-#ifdef ULE_DEBUG
-                       if (h.ule_where >= &h.ule_hist[100*TS_SZ]) h.ule_where = h.ule_hist;
-                       memcpy( h.ule_where, h.ts, TS_SZ );
-                       if (h.ule_dump) {
-                               hexdump( h.ule_where, TS_SZ );
-                               h.ule_dump = 0;
-                       }
-                       h.ule_where += TS_SZ;
-#endif
-
-                       /* Check TS h.error conditions: sync_byte, transport_error_indicator, scrambling_control . */
-                       if ((h.ts[0] != TS_SYNC) || (h.ts[1] & TS_TEI) || ((h.ts[3] & TS_SC) != 0)) {
-                               pr_warn("%lu: Invalid TS cell: SYNC %#x, TEI %u, SC %#x.\n",
-                                      h.priv->ts_count, h.ts[0],
-                                      (h.ts[1] & TS_TEI) >> 7,
-                                      (h.ts[3] & TS_SC) >> 6);
-
-                               /* Drop partly decoded SNDU, reset state, resync on PUSI. */
-                               if (h.priv->ule_skb) {
-                                       dev_kfree_skb( h.priv->ule_skb );
-                                       /* Prepare for next SNDU. */
-                                       h.dev->stats.rx_errors++;
-                                       h.dev->stats.rx_frame_errors++;
-                               }
-                               reset_ule(h.priv);
-                               h.priv->need_pusi = 1;
-
-                               /* Continue with next TS cell. */
-                               h.ts += TS_SZ;
-                               h.priv->ts_count++;
+                       if (dvb_net_ule_new_ts_cell(&h))
                                continue;
-                       }
-
-                       h.ts_remain = 184;
-                       h.from_where = h.ts + 4;
                }
+
                /* Synchronize on PUSI, if required. */
                if (h.priv->need_pusi) {
-                       if (h.ts[1] & TS_PUSI) {
-                               /* Find beginning of first ULE SNDU in current TS cell. */
-                               /* Synchronize continuity counter. */
-                               h.priv->tscc = h.ts[3] & 0x0F;
-                               /* There is a pointer field here. */
-                               if (h.ts[4] > h.ts_remain) {
-                                       pr_err("%lu: Invalid ULE packet (pointer field %d)\n",
-                                              h.priv->ts_count, h.ts[4]);
-                                       h.ts += TS_SZ;
-                                       h.priv->ts_count++;
-                                       continue;
-                               }
-                               /* Skip to destination of pointer field. */
-                               h.from_where = &h.ts[5] + h.ts[4];
-                               h.ts_remain -= 1 + h.ts[4];
-                               h.skipped = 0;
-                       } else {
-                               h.skipped++;
-                               h.ts += TS_SZ;
-                               h.priv->ts_count++;
+                       if (dvb_net_ule_ts_pusi(&h))
                                continue;
-                       }
                }
 
                if (h.new_ts) {
-                       /* Check continuity counter. */
-                       if ((h.ts[3] & 0x0F) == h.priv->tscc)
-                               h.priv->tscc = (h.priv->tscc + 1) & 0x0F;
-                       else {
-                               /* TS discontinuity handling: */
-                               pr_warn("%lu: TS discontinuity: got %#x, expected %#x.\n",
-                                       h.priv->ts_count, h.ts[3] & 0x0F,
-                                       h.priv->tscc);
-                               /* Drop partly decoded SNDU, reset state, resync on PUSI. */
-                               if (h.priv->ule_skb) {
-                                       dev_kfree_skb( h.priv->ule_skb );
-                                       /* Prepare for next SNDU. */
-                                       // reset_ule(h.priv);  moved to below.
-                                       h.dev->stats.rx_errors++;
-                                       h.dev->stats.rx_frame_errors++;
-                               }
-                               reset_ule(h.priv);
-                               /* skip to next PUSI. */
-                               h.priv->need_pusi = 1;
+                       if (dvb_net_ule_new_ts(&h))
                                continue;
-                       }
-                       /* If we still have an incomplete payload, but PUSI is
-                        * set; some TS cells are missing.
-                        * This is only possible here, if we missed exactly 16 TS
-                        * cells (continuity counter wrap). */
-                       if (h.ts[1] & TS_PUSI) {
-                               if (! h.priv->need_pusi) {
-                                       if (!(*h.from_where < (h.ts_remain-1)) || *h.from_where != h.priv->ule_sndu_remain) {
-                                               /* Pointer field is invalid.  Drop this TS cell and any started ULE SNDU. */
-                                               pr_warn("%lu: Invalid pointer field: %u.\n",
-                                                       h.priv->ts_count,
-                                                       *h.from_where);
-
-                                               /* Drop partly decoded SNDU, reset state, resync on PUSI. */
-                                               if (h.priv->ule_skb) {
-                                                       h.error = true;
-                                                       dev_kfree_skb(h.priv->ule_skb);
-                                               }
-
-                                               if (h.error || h.priv->ule_sndu_remain) {
-                                                       h.dev->stats.rx_errors++;
-                                                       h.dev->stats.rx_frame_errors++;
-                                                       h.error = false;
-                                               }
-
-                                               reset_ule(h.priv);
-                                               h.priv->need_pusi = 1;
-                                               continue;
-                                       }
-                                       /* Skip pointer field (we're processing a
-                                        * packed payload). */
-                                       h.from_where += 1;
-                                       h.ts_remain -= 1;
-                               } else
-                                       h.priv->need_pusi = 0;
-
-                               if (h.priv->ule_sndu_remain > 183) {
-                                       /* Current SNDU lacks more data than there could be available in the
-                                        * current TS cell. */
-                                       h.dev->stats.rx_errors++;
-                                       h.dev->stats.rx_length_errors++;
-                                       pr_warn("%lu: Expected %d more SNDU bytes, but got PUSI (pf %d, h.ts_remain %d).  Flushing incomplete payload.\n",
-                                               h.priv->ts_count,
-                                               h.priv->ule_sndu_remain,
-                                               h.ts[4], h.ts_remain);
-                                       dev_kfree_skb(h.priv->ule_skb);
-                                       /* Prepare for next SNDU. */
-                                       reset_ule(h.priv);
-                                       /* Resync: go to where pointer field points to: start of next ULE SNDU. */
-                                       h.from_where += h.ts[4];
-                                       h.ts_remain -= h.ts[4];
-                               }
-                       }
                }
 
                /* Check if new payload needs to be started. */
                if (h.priv->ule_skb == NULL) {
-                       /* Start a new payload with skb.
-                        * Find ULE header.  It is only guaranteed that the
-                        * length field (2 bytes) is contained in the current
-                        * TS.
-                        * Check h.ts_remain has to be >= 2 here. */
-                       if (h.ts_remain < 2) {
-                               pr_warn("Invalid payload packing: only %d bytes left in TS.  Resyncing.\n",
-                                       h.ts_remain);
-                               h.priv->ule_sndu_len = 0;
-                               h.priv->need_pusi = 1;
-                               h.ts += TS_SZ;
-                               continue;
-                       }
-
-                       if (! h.priv->ule_sndu_len) {
-                               /* Got at least two bytes, thus extrace the SNDU length. */
-                               h.priv->ule_sndu_len = h.from_where[0] << 8 | h.from_where[1];
-                               if (h.priv->ule_sndu_len & 0x8000) {
-                                       /* D-Bit is set: no dest mac present. */
-                                       h.priv->ule_sndu_len &= 0x7FFF;
-                                       h.priv->ule_dbit = 1;
-                               } else
-                                       h.priv->ule_dbit = 0;
-
-                               if (h.priv->ule_sndu_len < 5) {
-                                       pr_warn("%lu: Invalid ULE SNDU length %u. Resyncing.\n",
-                                               h.priv->ts_count,
-                                               h.priv->ule_sndu_len);
-                                       h.dev->stats.rx_errors++;
-                                       h.dev->stats.rx_length_errors++;
-                                       h.priv->ule_sndu_len = 0;
-                                       h.priv->need_pusi = 1;
-                                       h.new_ts = 1;
-                                       h.ts += TS_SZ;
-                                       h.priv->ts_count++;
-                                       continue;
-                               }
-                               h.ts_remain -= 2;       /* consume the 2 bytes SNDU length. */
-                               h.from_where += 2;
-                       }
-
-                       h.priv->ule_sndu_remain = h.priv->ule_sndu_len + 2;
-                       /*
-                        * State of current TS:
-                        *   h.ts_remain (remaining bytes in the current TS cell)
-                        *   0  ule_type is not available now, we need the next TS cell
-                        *   1  the first byte of the ule_type is present
-                        * >=2  full ULE header present, maybe some payload data as well.
-                        */
-                       switch (h.ts_remain) {
-                               case 1:
-                                       h.priv->ule_sndu_remain--;
-                                       h.priv->ule_sndu_type = h.from_where[0] << 8;
-                                       h.priv->ule_sndu_type_1 = 1; /* first byte of ule_type is set. */
-                                       h.ts_remain -= 1; h.from_where += 1;
-                                       /* Continue w/ next TS. */
-                               case 0:
-                                       h.new_ts = 1;
-                                       h.ts += TS_SZ;
-                                       h.priv->ts_count++;
-                                       continue;
-
-                               default: /* complete ULE header is present in current TS. */
-                                       /* Extract ULE type field. */
-                                       if (h.priv->ule_sndu_type_1) {
-                                               h.priv->ule_sndu_type_1 = 0;
-                                               h.priv->ule_sndu_type |= h.from_where[0];
-                                               h.from_where += 1; /* points to payload start. */
-                                               h.ts_remain -= 1;
-                                       } else {
-                                               /* Complete type is present in new TS. */
-                                               h.priv->ule_sndu_type = h.from_where[0] << 8 | h.from_where[1];
-                                               h.from_where += 2; /* points to payload start. */
-                                               h.ts_remain -= 2;
-                                       }
-                                       break;
-                       }
-
-                       /* Allocate the skb (decoder target buffer) with the correct size, as follows:
-                        * prepare for the largest case: bridged SNDU with MAC address (dbit = 0). */
-                       h.priv->ule_skb = dev_alloc_skb( h.priv->ule_sndu_len + ETH_HLEN + ETH_ALEN );
-                       if (h.priv->ule_skb == NULL) {
-                               pr_notice("%s: Memory squeeze, dropping packet.\n",
-                                         h.dev->name);
-                               h.dev->stats.rx_dropped++;
+                       ret = dvb_net_ule_new_payload(&h);
+                       if (ret < 0)
                                return;
-                       }
-
-                       /* This includes the CRC32 _and_ dest mac, if !dbit. */
-                       h.priv->ule_sndu_remain = h.priv->ule_sndu_len;
-                       h.priv->ule_skb->dev = h.dev;
-                       /* Leave space for Ethernet or bridged SNDU header (eth hdr plus one MAC addr). */
-                       skb_reserve( h.priv->ule_skb, ETH_HLEN + ETH_ALEN );
+                       if (ret)
+                               continue;
                }
 
                /* Copy data into our current skb. */
                h.how_much = min(h.priv->ule_sndu_remain, (int)h.ts_remain);
-               memcpy(skb_put(h.priv->ule_skb, h.how_much), h.from_where, h.how_much);
+               memcpy(skb_put(h.priv->ule_skb, h.how_much),
+                      h.from_where, h.how_much);
                h.priv->ule_sndu_remain -= h.how_much;
                h.ts_remain -= h.how_much;
                h.from_where += h.how_much;
@@ -610,7 +851,8 @@ static void dvb_net_ule(struct net_device *dev, const u8 *buf, size_t buf_len)
                        struct kvec iov[3] = {
                                { &ulen, sizeof ulen },
                                { &utype, sizeof utype },
-                               { h.priv->ule_skb->data, h.priv->ule_skb->len - 4 }
+                               { h.priv->ule_skb->data,
+                                 h.priv->ule_skb->len - 4 }
                        };
                        u32 ule_crc = ~0L, expected_crc;
                        if (h.priv->ule_dbit) {
@@ -625,145 +867,9 @@ static void dvb_net_ule(struct net_device *dev, const u8 *buf, size_t buf_len)
                                       *(tail - 3) << 16 |
                                       *(tail - 2) << 8 |
                                       *(tail - 1);
-                       if (ule_crc != expected_crc) {
-                               pr_warn("%lu: CRC32 check FAILED: %08x / %08x, SNDU len %d type %#x, h.ts_remain %d, next 2: %x.\n",
-                                      h.priv->ts_count, ule_crc, expected_crc,
-                                      h.priv->ule_sndu_len, h.priv->ule_sndu_type,
-                                      h.ts_remain,
-                                      h.ts_remain > 2 ? *(unsigned short *)h.from_where : 0);
 
-#ifdef ULE_DEBUG
-                               hexdump( iov[0].iov_base, iov[0].iov_len );
-                               hexdump( iov[1].iov_base, iov[1].iov_len );
-                               hexdump( iov[2].iov_base, iov[2].iov_len );
-
-                               if (h.ule_where == h.ule_hist) {
-                                       hexdump( &h.ule_hist[98*TS_SZ], TS_SZ );
-                                       hexdump( &h.ule_hist[99*TS_SZ], TS_SZ );
-                               } else if (h.ule_where == &h.ule_hist[TS_SZ]) {
-                                       hexdump( &h.ule_hist[99*TS_SZ], TS_SZ );
-                                       hexdump( h.ule_hist, TS_SZ );
-                               } else {
-                                       hexdump( h.ule_where - TS_SZ - TS_SZ, TS_SZ );
-                                       hexdump( h.ule_where - TS_SZ, TS_SZ );
-                               }
-                               h.ule_dump = 1;
-#endif
+                       dvb_net_ule_check_crc(&h, ule_crc, expected_crc);
 
-                               h.dev->stats.rx_errors++;
-                               h.dev->stats.rx_crc_errors++;
-                               dev_kfree_skb(h.priv->ule_skb);
-                       } else {
-                               /* CRC32 verified OK. */
-                               u8 dest_addr[ETH_ALEN];
-                               static const u8 bc_addr[ETH_ALEN] =
-                                       { [ 0 ... ETH_ALEN-1] = 0xff };
-
-                               /* CRC32 was OK. Remove it from skb. */
-                               h.priv->ule_skb->tail -= 4;
-                               h.priv->ule_skb->len -= 4;
-
-                               if (!h.priv->ule_dbit) {
-                                       /*
-                                        * The destination MAC address is the
-                                        * next data in the skb.  It comes
-                                        * before any extension headers.
-                                        *
-                                        * Check if the payload of this SNDU
-                                        * should be passed up the stack.
-                                        */
-                                       register int drop = 0;
-                                       if (h.priv->rx_mode != RX_MODE_PROMISC) {
-                                               if (h.priv->ule_skb->data[0] & 0x01) {
-                                                       /* multicast or broadcast */
-                                                       if (!ether_addr_equal(h.priv->ule_skb->data, bc_addr)) {
-                                                               /* multicast */
-                                                               if (h.priv->rx_mode == RX_MODE_MULTI) {
-                                                                       int i;
-                                                                       for(i = 0; i < h.priv->multi_num &&
-                                                                           !ether_addr_equal(h.priv->ule_skb->data,
-                                                                                             h.priv->multi_macs[i]); i++)
-                                                                               ;
-                                                                       if (i == h.priv->multi_num)
-                                                                               drop = 1;
-                                                               } else if (h.priv->rx_mode != RX_MODE_ALL_MULTI)
-                                                                       drop = 1; /* no broadcast; */
-                                                               /* else: all multicast mode: accept all multicast packets */
-                                                       }
-                                                       /* else: broadcast */
-                                               }
-                                               else if (!ether_addr_equal(h.priv->ule_skb->data, h.dev->dev_addr))
-                                                       drop = 1;
-                                               /* else: destination address matches the MAC address of our receiver device */
-                                       }
-                                       /* else: promiscuous mode; pass everything up the stack */
-
-                                       if (drop) {
-#ifdef ULE_DEBUG
-                                               netdev_dbg(h.dev, "Dropping SNDU: MAC destination address does not match: dest addr: %pM, h.dev addr: %pM\n",
-                                                          h.priv->ule_skb->data, h.dev->dev_addr);
-#endif
-                                               dev_kfree_skb(h.priv->ule_skb);
-                                               goto sndu_done;
-                                       }
-                                       else
-                                       {
-                                               skb_copy_from_linear_data(h.priv->ule_skb,
-                                                             dest_addr,
-                                                             ETH_ALEN);
-                                               skb_pull(h.priv->ule_skb, ETH_ALEN);
-                                       }
-                               }
-
-                               /* Handle ULE Extension Headers. */
-                               if (h.priv->ule_sndu_type < ETH_P_802_3_MIN) {
-                                       /* There is an extension header.  Handle it accordingly. */
-                                       int l = handle_ule_extensions(h.priv);
-                                       if (l < 0) {
-                                               /* Mandatory extension header unknown or TEST SNDU.  Drop it. */
-                                               // pr_warn("Dropping SNDU, extension headers.\n" );
-                                               dev_kfree_skb(h.priv->ule_skb);
-                                               goto sndu_done;
-                                       }
-                                       skb_pull(h.priv->ule_skb, l);
-                               }
-
-                               /*
-                                * Construct/assure correct ethernet header.
-                                * Note: in bridged mode (h.priv->ule_bridged !=
-                                * 0) we already have the (original) ethernet
-                                * header at the start of the payload (after
-                                * optional dest. address and any extension
-                                * headers).
-                                */
-
-                               if (!h.priv->ule_bridged) {
-                                       skb_push(h.priv->ule_skb, ETH_HLEN);
-                                       h.ethh = (struct ethhdr *)h.priv->ule_skb->data;
-                                       if (!h.priv->ule_dbit) {
-                                                /* dest_addr buffer is only valid if h.priv->ule_dbit == 0 */
-                                               memcpy(h.ethh->h_dest, dest_addr, ETH_ALEN);
-                                               eth_zero_addr(h.ethh->h_source);
-                                       }
-                                       else /* zeroize source and dest */
-                                               memset( h.ethh, 0, ETH_ALEN*2 );
-
-                                       h.ethh->h_proto = htons(h.priv->ule_sndu_type);
-                               }
-                               /* else:  skb is in correct state; nothing to do. */
-                               h.priv->ule_bridged = 0;
-
-                               /* Stuff into kernel's protocol stack. */
-                               h.priv->ule_skb->protocol = dvb_net_eth_type_trans(h.priv->ule_skb, h.dev);
-                               /* If D-bit is set (i.e. destination MAC address not present),
-                                * receive the packet anyhow. */
-                               /* if (h.priv->ule_dbit && skb->pkt_type == PACKET_OTHERHOST)
-                                       h.priv->ule_skb->pkt_type = PACKET_HOST; */
-                               h.dev->stats.rx_packets++;
-                               h.dev->stats.rx_bytes += h.priv->ule_skb->len;
-                               netif_rx(h.priv->ule_skb);
-                       }
-                       sndu_done:
                        /* Prepare for next SNDU. */
                        reset_ule(h.priv);
                }