1Generic networking statistics for netlink users 2====================================================================== 3 4Statistic counters are grouped into structs: 5 6Struct TLV type Description 7---------------------------------------------------------------------- 8gnet_stats_basic TCA_STATS_BASIC Basic statistics 9gnet_stats_rate_est TCA_STATS_RATE_EST Rate estimator 10gnet_stats_queue TCA_STATS_QUEUE Queue statistics 11none TCA_STATS_APP Application specific 12 13 14Collecting: 15----------- 16 17Declare the statistic structs you need: 18struct mystruct { 19 struct gnet_stats_basic bstats; 20 struct gnet_stats_queue qstats; 21 ... 22}; 23 24Update statistics: 25mystruct->tstats.packet++; 26mystruct->qstats.backlog += skb->pkt_len; 27 28 29Export to userspace (Dump): 30--------------------------- 31 32my_dumping_routine(struct sk_buff *skb, ...) 33{ 34 struct gnet_dump dump; 35 36 if (gnet_stats_start_copy(skb, TCA_STATS2, &mystruct->lock, &dump) < 0) 37 goto rtattr_failure; 38 39 if (gnet_stats_copy_basic(&dump, &mystruct->bstats) < 0 || 40 gnet_stats_copy_queue(&dump, &mystruct->qstats) < 0 || 41 gnet_stats_copy_app(&dump, &xstats, sizeof(xstats)) < 0) 42 goto rtattr_failure; 43 44 if (gnet_stats_finish_copy(&dump) < 0) 45 goto rtattr_failure; 46 ... 47} 48 49TCA_STATS/TCA_XSTATS backward compatibility: 50-------------------------------------------- 51 52Prior users of struct tc_stats and xstats can maintain backward 53compatibility by calling the compat wrappers to keep providing the 54existing TLV types. 55 56my_dumping_routine(struct sk_buff *skb, ...) 57{ 58 if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, 59 TCA_XSTATS, &mystruct->lock, &dump) < 0) 60 goto rtattr_failure; 61 ... 62} 63 64A struct tc_stats will be filled out during gnet_stats_copy_* calls 65and appended to the skb. TCA_XSTATS is provided if gnet_stats_copy_app 66was called. 67 68 69Locking: 70-------- 71 72Locks are taken before writing and released once all statistics have 73been written. Locks are always released in case of an error. You 74are responsible for making sure that the lock is initialized. 75 76 77Rate Estimator: 78-------------- 79 800) Prepare an estimator attribute. Most likely this would be in user 81 space. The value of this TLV should contain a tc_estimator structure. 82 As usual, such a TLV needs to be 32 bit aligned and therefore the 83 length needs to be appropriately set, etc. The estimator interval 84 and ewma log need to be converted to the appropriate values. 85 tc_estimator.c::tc_setup_estimator() is advisable to be used as the 86 conversion routine. It does a few clever things. It takes a time 87 interval in microsecs, a time constant also in microsecs and a struct 88 tc_estimator to be populated. The returned tc_estimator can be 89 transported to the kernel. Transfer such a structure in a TLV of type 90 TCA_RATE to your code in the kernel. 91 92In the kernel when setting up: 931) make sure you have basic stats and rate stats setup first. 942) make sure you have initialized stats lock that is used to setup such 95 stats. 963) Now initialize a new estimator: 97 98 int ret = gen_new_estimator(my_basicstats,my_rate_est_stats, 99 mystats_lock, attr_with_tcestimator_struct); 100 101 if ret == 0 102 success 103 else 104 failed 105 106From now on, every time you dump my_rate_est_stats it will contain 107up-to-date info. 108 109Once you are done, call gen_kill_estimator(my_basicstats, 110my_rate_est_stats) Make sure that my_basicstats and my_rate_est_stats 111are still valid (i.e still exist) at the time of making this call. 112 113 114Authors: 115-------- 116Thomas Graf <tgraf@suug.ch> 117Jamal Hadi Salim <hadi@cyberus.ca> 118