[SERVER] Get rid of alt-servers thread, per-uplink rtt history

Alt-Server checks are now run using the threadpool, so we don't need a
queue and dedicated thread anymore. The rtt history is now kept per
uplink, so many uplinks won't overwhelm the history, making its time
window very short.
Also the fail counter is now split up; a global one for when the server
actually isn't reachable, a local (per-uplink) one for when the server
is reachable but doesn't serve the requested image.

1 files changed, 26 insertions, 15 deletions

diff --git a/src/server/globals.h b/src/server/globals.h
index 659e5a2..4d97c6b 100644
--- a/src/server/globals.h
+++ b/src/server/globals.h
@@ -30,10 +30,31 @@ typedef struct
 	uint8_t hopCount;      // How many hops this request has already taken across proxies
 } dnbd3_queued_request_t;
 
+typedef struct
+{
+	int fails;                    // Hard fail: Connection failed
+	int rttIndex;
+	uint32_t rtt[SERVER_RTT_PROBES];
+	bool isPrivate, isClientOnly;
+	bool blocked;                 // If true count down fails until 0 to enable again
+	ticks lastFail;               // Last hard fail
+	dnbd3_host_t host;
+	char comment[COMMENT_LENGTH];
+} dnbd3_alt_server_t;
+
+typedef struct
+{
+	int fails;                    // Soft fail: Image not found
+	int rttIndex;
+	uint32_t rtt[SERVER_RTT_PROBES];
+	bool blocked;                 // True if server is to be ignored and fails should be counted down
+	bool initDone;
+} dnbd3_alt_local_t;
+
 typedef struct {
-	int fd;             // Socket fd for this connection
-	int version;        // Protocol version of remote server
-	dnbd3_host_t host;  // IP/Port of remote server
+	int fd;            // Socket fd for this connection
+	int version;       // Protocol version of remote server
+	int index;         // Entry in uplinks list
 } dnbd3_server_connection_t;
 
 #define RTT_IDLE 0 // Not in progress
@@ -51,7 +72,7 @@ struct _dnbd3_uplink
 	pthread_mutex_t queueLock;  // lock for synchronization on request queue etc.
 	dnbd3_image_t *image;       // image that this uplink is used for; do not call get/release for this pointer
 	pthread_mutex_t rttLock;    // When accessing rttTestResult, betterFd or betterServer
-	int rttTestResult;          // RTT_*
+	atomic_int rttTestResult;   // RTT_*
 	int cacheFd;                // used to write to the image, in case it is relayed. ONLY USE FROM UPLINK THREAD!
 	uint8_t *recvBuffer;        // Buffer for receiving payload
 	uint32_t recvBufferLen;     // Len of ^^
@@ -65,21 +86,11 @@ struct _dnbd3_uplink
 	atomic_int queueLen;        // length of queue
 	uint32_t idleTime;          // How many seconds the uplink was idle (apart from keep-alives)
 	dnbd3_queued_request_t queue[SERVER_MAX_UPLINK_QUEUE];
+	dnbd3_alt_local_t altData[SERVER_MAX_ALTS];
 };
 
 typedef struct
 {
-	char comment[COMMENT_LENGTH];
-	dnbd3_host_t host;
-	unsigned int rtt[SERVER_RTT_PROBES];
-	unsigned int rttIndex;
-	bool isPrivate, isClientOnly;
-	ticks lastFail;
-	int numFails;
-} dnbd3_alt_server_t;
-
-typedef struct
-{
 	uint8_t host[16];
 	int bytes;
 	int bitMask;