multipath_rr.c 2.3 KB

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  1. /*
  2. * Round robin policy for multipath.
  3. *
  4. *
  5. * Version: $Id: multipath_rr.c,v 1.1.1.1 2007/06/12 07:27:14 eyryu Exp $
  6. *
  7. * Authors: Einar Lueck <elueck@de.ibm.com><lkml@einar-lueck.de>
  8. *
  9. * This program is free software; you can redistribute it and/or
  10. * modify it under the terms of the GNU General Public License
  11. * as published by the Free Software Foundation; either version
  12. * 2 of the License, or (at your option) any later version.
  13. */
  14. #include <asm/system.h>
  15. #include <asm/uaccess.h>
  16. #include <linux/types.h>
  17. #include <linux/errno.h>
  18. #include <linux/timer.h>
  19. #include <linux/mm.h>
  20. #include <linux/kernel.h>
  21. #include <linux/fcntl.h>
  22. #include <linux/stat.h>
  23. #include <linux/socket.h>
  24. #include <linux/in.h>
  25. #include <linux/inet.h>
  26. #include <linux/netdevice.h>
  27. #include <linux/inetdevice.h>
  28. #include <linux/igmp.h>
  29. #include <linux/proc_fs.h>
  30. #include <linux/seq_file.h>
  31. #include <linux/module.h>
  32. #include <linux/mroute.h>
  33. #include <linux/init.h>
  34. #include <net/ip.h>
  35. #include <net/protocol.h>
  36. #include <linux/skbuff.h>
  37. #include <net/sock.h>
  38. #include <net/icmp.h>
  39. #include <net/udp.h>
  40. #include <net/raw.h>
  41. #include <linux/notifier.h>
  42. #include <linux/if_arp.h>
  43. #include <linux/netfilter_ipv4.h>
  44. #include <net/ipip.h>
  45. #include <net/checksum.h>
  46. #include <net/ip_mp_alg.h>
  47. static void rr_select_route(const struct flowi *flp,
  48. struct rtable *first, struct rtable **rp)
  49. {
  50. struct rtable *nh, *result, *min_use_cand = NULL;
  51. int min_use = -1;
  52. /* 1. make sure all alt. nexthops have the same GC related data
  53. * 2. determine the new candidate to be returned
  54. */
  55. result = NULL;
  56. for (nh = rcu_dereference(first); nh;
  57. nh = rcu_dereference(nh->u.dst.rt_next)) {
  58. if ((nh->u.dst.flags & DST_BALANCED) != 0 &&
  59. multipath_comparekeys(&nh->fl, flp)) {
  60. nh->u.dst.lastuse = jiffies;
  61. if (min_use == -1 || nh->u.dst.__use < min_use) {
  62. min_use = nh->u.dst.__use;
  63. min_use_cand = nh;
  64. }
  65. }
  66. }
  67. result = min_use_cand;
  68. if (!result)
  69. result = first;
  70. result->u.dst.__use++;
  71. *rp = result;
  72. }
  73. static struct ip_mp_alg_ops rr_ops = {
  74. .mp_alg_select_route = rr_select_route,
  75. };
  76. static int __init rr_init(void)
  77. {
  78. return multipath_alg_register(&rr_ops, IP_MP_ALG_RR);
  79. }
  80. static void __exit rr_exit(void)
  81. {
  82. multipath_alg_unregister(&rr_ops, IP_MP_ALG_RR);
  83. }
  84. module_init(rr_init);
  85. module_exit(rr_exit);
  86. MODULE_LICENSE("GPL");