mirror of
https://github.com/matrix-org/dendrite
synced 2024-12-14 14:33:50 +01:00
b5aa7ca3ab
* Move config, setup, mscs into "setup" top-level folder * oops, forgot the EDU server * Add setup * goimports
109 lines
2.9 KiB
Go
109 lines
2.9 KiB
Go
package routing
|
|
|
|
import (
|
|
"net/http"
|
|
"sync"
|
|
"time"
|
|
|
|
"github.com/matrix-org/dendrite/clientapi/jsonerror"
|
|
"github.com/matrix-org/dendrite/setup/config"
|
|
"github.com/matrix-org/util"
|
|
)
|
|
|
|
type rateLimits struct {
|
|
limits map[string]chan struct{}
|
|
limitsMutex sync.RWMutex
|
|
cleanMutex sync.RWMutex
|
|
enabled bool
|
|
requestThreshold int64
|
|
cooloffDuration time.Duration
|
|
}
|
|
|
|
func newRateLimits(cfg *config.RateLimiting) *rateLimits {
|
|
l := &rateLimits{
|
|
limits: make(map[string]chan struct{}),
|
|
enabled: cfg.Enabled,
|
|
requestThreshold: cfg.Threshold,
|
|
cooloffDuration: time.Duration(cfg.CooloffMS) * time.Millisecond,
|
|
}
|
|
if l.enabled {
|
|
go l.clean()
|
|
}
|
|
return l
|
|
}
|
|
|
|
func (l *rateLimits) clean() {
|
|
for {
|
|
// On a 30 second interval, we'll take an exclusive write
|
|
// lock of the entire map and see if any of the channels are
|
|
// empty. If they are then we will close and delete them,
|
|
// freeing up memory.
|
|
time.Sleep(time.Second * 30)
|
|
l.cleanMutex.Lock()
|
|
l.limitsMutex.Lock()
|
|
for k, c := range l.limits {
|
|
if len(c) == 0 {
|
|
close(c)
|
|
delete(l.limits, k)
|
|
}
|
|
}
|
|
l.limitsMutex.Unlock()
|
|
l.cleanMutex.Unlock()
|
|
}
|
|
}
|
|
|
|
func (l *rateLimits) rateLimit(req *http.Request) *util.JSONResponse {
|
|
// If rate limiting is disabled then do nothing.
|
|
if !l.enabled {
|
|
return nil
|
|
}
|
|
|
|
// Take a read lock out on the cleaner mutex. The cleaner expects to
|
|
// be able to take a write lock, which isn't possible while there are
|
|
// readers, so this has the effect of blocking the cleaner goroutine
|
|
// from doing its work until there are no requests in flight.
|
|
l.cleanMutex.RLock()
|
|
defer l.cleanMutex.RUnlock()
|
|
|
|
// First of all, work out if X-Forwarded-For was sent to us. If not
|
|
// then we'll just use the IP address of the caller.
|
|
caller := req.RemoteAddr
|
|
if forwardedFor := req.Header.Get("X-Forwarded-For"); forwardedFor != "" {
|
|
caller = forwardedFor
|
|
}
|
|
|
|
// Look up the caller's channel, if they have one.
|
|
l.limitsMutex.RLock()
|
|
rateLimit, ok := l.limits[caller]
|
|
l.limitsMutex.RUnlock()
|
|
|
|
// If the caller doesn't have a channel, create one and write it
|
|
// back to the map.
|
|
if !ok {
|
|
rateLimit = make(chan struct{}, l.requestThreshold)
|
|
|
|
l.limitsMutex.Lock()
|
|
l.limits[caller] = rateLimit
|
|
l.limitsMutex.Unlock()
|
|
}
|
|
|
|
// Check if the user has got free resource slots for this request.
|
|
// If they don't then we'll return an error.
|
|
select {
|
|
case rateLimit <- struct{}{}:
|
|
default:
|
|
// We hit the rate limit. Tell the client to back off.
|
|
return &util.JSONResponse{
|
|
Code: http.StatusTooManyRequests,
|
|
JSON: jsonerror.LimitExceeded("You are sending too many requests too quickly!", l.cooloffDuration.Milliseconds()),
|
|
}
|
|
}
|
|
|
|
// After the time interval, drain a resource from the rate limiting
|
|
// channel. This will free up space in the channel for new requests.
|
|
go func() {
|
|
<-time.After(l.cooloffDuration)
|
|
<-rateLimit
|
|
}()
|
|
return nil
|
|
}
|