2 Commits (b2c55e62c89a72d51c12a4305d24a2c3f290dd39)

Author	SHA1	Message	Date
Joe Tsai	d9df023e6f	net/connstats: enforce maximum number of connections (#6760) ... The Tailscale logging service has a hard limit on the maximum log message size that can be accepted. We want to ensure that netlog messages never exceed this limit otherwise a client cannot transmit logs. Move the goroutine for periodically dumping netlog messages from wgengine/netlog to net/connstats. This allows net/connstats to manage when it dumps messages, either based on time or by size. Updates tailscale/corp#8427 Signed-off-by: Joe Tsai <joetsai@digital-static.net>	2 years ago
Joe Tsai	2e5d08ec4f	net/connstats: invert network logging data flow (#6272) ... Previously, tstun.Wrapper and magicsock.Conn managed their own statistics data structure and relied on an external call to Extract to extract (and reset) the statistics. This makes it difficult to ensure a maximum size on the statistics as the caller has no introspection into whether the number of unique connections is getting too large. Invert the control flow such that a *connstats.Statistics is registered with tstun.Wrapper and magicsock.Conn. Methods on non-nil *connstats.Statistics are called for every packet. This allows the implementation of connstats.Statistics (in the future) to better control when it needs to flush to ensure bounds on maximum sizes. The value registered into tstun.Wrapper and magicsock.Conn could be an interface, but that has two performance detriments: 1. Method calls on interface values are more expensive since they must go through a virtual method dispatch. 2. The implementation would need a sync.Mutex to protect the statistics value instead of using an atomic.Pointer. Given that methods on constats.Statistics are called for every packet, we want reduce the CPU cost on this hot path. Signed-off-by: Joe Tsai <joetsai@digital-static.net>	2 years ago