[ngIRCd-GIT-ML] Alexander Barton : Handle "throttling" in a single function

Module: ngircd.git Branch: master Commit: 35f1db5f28245579efbbb06eed6eaf1a3d6d84bc URL: http://ngircd.barton.de/cgi-bin/gitweb.cgi?p=ngircd.git&a=commit;h=35f1d...

Author: Alexander Barton alex@barton.de Date: Tue Mar 18 14:48:52 2014 +0100

Handle "throttling" in a single function

ngIRCd uses "command throttling" and "bps throttling" (bytes per second). The states are detected in different functions, Conn_Handler() and Read_Request(), but handle the actual "throttling" in a common function: this enables us to guarantee consistent behavior and to disable throttling for special connections in only one place, eventually.

---

src/ngircd/conn.c | 65 +++++++++++++++++++++++++++++++++++------------------ 1 file changed, 43 insertions(+), 22 deletions(-)

diff --git a/src/ngircd/conn.c b/src/ngircd/conn.c index 4dfe62f..77c8cd8 100644 --- a/src/ngircd/conn.c +++ b/src/ngircd/conn.c @@ -74,6 +74,9 @@

#define SD_LISTEN_FDS_START 3 /** systemd(8) socket activation offset */

+#define THROTTLE_CMDS 1 /** Throttling: max commands reached */ +#define THROTTLE_BPS 2 /** Throttling: max bps reached */ + static bool Handle_Write PARAMS(( CONN_ID Idx )); static bool Conn_Write PARAMS(( CONN_ID Idx, char *Data, size_t Len )); static int New_Connection PARAMS(( int Sock, bool IsSSL )); @@ -88,6 +91,8 @@ static void New_Server PARAMS(( int Server, ng_ipaddr_t *dest )); static void Simple_Message PARAMS(( int Sock, const char *Msg )); static int NewListener PARAMS(( const char *listen_addr, UINT16 Port )); static void Account_Connection PARAMS((void)); +static void Throttle_Connection PARAMS((const CONN_ID Idx, CLIENT *Client, + const int Reason, unsigned int Value));

static array My_Listeners; static array My_ConnArray; @@ -665,7 +670,7 @@ GLOBAL void Conn_Handler(void) { int i; - size_t wdatalen, bytes_processed; + size_t wdatalen; struct timeval tv; time_t t;

@@ -684,17 +689,7 @@ Conn_Handler(void) if ((My_Connections[i].sock > NONE) && (array_bytes(&My_Connections[i].rbuf) > 0)) { /* ... and try to handle the received data */ - bytes_processed = Handle_Buffer(i); - /* if we processed data, and there might be - * more commands in the input buffer, do not - * try to read any more data now */ - if (bytes_processed && - array_bytes(&My_Connections[i].rbuf) > 2) { - LogDebug - ("Throttling connection %d: command limit reached!", - i); - Conn_SetPenalty(i, 1); - } + Handle_Buffer(i); } }

@@ -1573,8 +1568,8 @@ Read_Request( CONN_ID Idx ) { /* Read buffer is full */ Log(LOG_ERR, - "Receive buffer space exhausted (connection %d): %d bytes", - Idx, array_bytes(&My_Connections[Idx].rbuf)); + "Receive buffer space exhausted (connection %d): %d/%d bytes", + Idx, array_bytes(&My_Connections[Idx].rbuf), READBUFFER_LEN); Conn_Close(Idx, "Receive buffer space exhausted", NULL, false); return; } @@ -1626,6 +1621,8 @@ Read_Request( CONN_ID Idx )

/* Update connection statistics */ My_Connections[Idx].bytes_in += len; + + /* Handle read buffer */ My_Connections[Idx].bps += Handle_Buffer(Idx);

/* Make sure that there is still a valid client registered */ @@ -1651,14 +1648,8 @@ Read_Request( CONN_ID Idx ) }

/* Look at the data in the (read-) buffer of this connection */ - if (Client_Type(c) != CLIENT_SERVER - && Client_Type(c) != CLIENT_UNKNOWNSERVER - && Client_Type(c) != CLIENT_SERVICE - && My_Connections[Idx].bps >= maxbps) { - LogDebug("Throttling connection %d: BPS exceeded! (%u >= %u)", - Idx, My_Connections[Idx].bps, maxbps); - Conn_SetPenalty(Idx, 1); - } + if (My_Connections[Idx].bps >= maxbps) + Throttle_Connection(Idx, c, THROTTLE_BPS, maxbps); } /* Read_Request */

/** @@ -1827,6 +1818,11 @@ Handle_Buffer(CONN_ID Idx) array_bytes(&My_Connections[Idx].rbuf)); #endif

+ /* If data has been processed but there is still data in the read + * buffer, the command limit triggered. Enforce the penalty time: */ + if (len_processed && array_bytes(&My_Connections[Idx].rbuf) > 2) + Throttle_Connection(Idx, c, THROTTLE_CMDS, maxcmd); + return len_processed; } /* Handle_Buffer */

@@ -2410,6 +2406,31 @@ Conn_GetFromProc(int fd) return NONE; } /* Conn_GetFromProc */

+/** + * Throttle a connection because of excessive usage. + * + * @param Reason The reason, see THROTTLE_xxx constants. + * @param Idx The connection index. + * @param Client The client of this connection. + * @param Seconds The time to delay this connection. + */ +static void +Throttle_Connection(const CONN_ID Idx, CLIENT *Client, const int Reason, + unsigned int Value) +{ + assert(Idx > NONE); + assert(Client != NULL); + + /* Never throttle servers or services, only interrupt processing */ + if (Client_Type(Client) == CLIENT_SERVER + || Client_Type(Client) == CLIENT_UNKNOWNSERVER + || Client_Type(Client) == CLIENT_SERVICE) + return; + + LogDebug("Throttling connection %d: code %d, value %d!", Idx, + Reason, Value); + Conn_SetPenalty(Idx, 1); +}

#ifndef STRICT_RFC