tag_trailer.c 1.4 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465
  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * net/dsa/tag_trailer.c - Trailer tag format handling
  4. * Copyright (c) 2008-2009 Marvell Semiconductor
  5. */
  6. #include <linux/etherdevice.h>
  7. #include <linux/list.h>
  8. #include <linux/slab.h>
  9. #include "dsa_priv.h"
  10. static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev)
  11. {
  12. struct dsa_port *dp = dsa_slave_to_port(dev);
  13. u8 *trailer;
  14. trailer = skb_put(skb, 4);
  15. trailer[0] = 0x80;
  16. trailer[1] = 1 << dp->index;
  17. trailer[2] = 0x10;
  18. trailer[3] = 0x00;
  19. return skb;
  20. }
  21. static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev,
  22. struct packet_type *pt)
  23. {
  24. u8 *trailer;
  25. int source_port;
  26. if (skb_linearize(skb))
  27. return NULL;
  28. trailer = skb_tail_pointer(skb) - 4;
  29. if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 ||
  30. (trailer[2] & 0xef) != 0x00 || trailer[3] != 0x00)
  31. return NULL;
  32. source_port = trailer[1] & 7;
  33. skb->dev = dsa_master_find_slave(dev, 0, source_port);
  34. if (!skb->dev)
  35. return NULL;
  36. if (pskb_trim_rcsum(skb, skb->len - 4))
  37. return NULL;
  38. return skb;
  39. }
  40. static const struct dsa_device_ops trailer_netdev_ops = {
  41. .name = "trailer",
  42. .proto = DSA_TAG_PROTO_TRAILER,
  43. .xmit = trailer_xmit,
  44. .rcv = trailer_rcv,
  45. .overhead = 4,
  46. .tail_tag = true,
  47. };
  48. MODULE_LICENSE("GPL");
  49. MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_TRAILER);
  50. module_dsa_tag_driver(trailer_netdev_ops);