ngircd

Free, portable and lightweight Internet Relay Chat server http://ngircd.barton.de/
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commit 35f1db5f28245579efbbb06eed6eaf1a3d6d84bc
parent 4c2acd55c6ecb8d9a6a1c6c5c86295fdd859820c
Author: Alexander Barton <alex@barton.de>
Date:   Tue, 18 Mar 2014 14:48:52 +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.

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

diff --git 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