commit c6e3c13f27744971fcb1d2de4e561d3bcdaa5aed
from: michi <michi+ngircd@dataswamp.org>
via: Alexander Barton <alex@barton.de>
date: Sun Apr 19 22:20:46 2020 UTC

Increase read buffer size for server connections

This applies the same logic we have for write buffers to distinguish
between server and client connections and sets the maximum buffer size
accordingly. As a result peering with servers with many GLINE/KLINEs
does not kill the connecting server connection anymore.

commit - 04de1423eb26da60c192d343a7e7a6bcda2aca37
commit + c6e3c13f27744971fcb1d2de4e561d3bcdaa5aed
blob - 92d9939ab291445e53806b75609dfaa8209915ad
blob + ef0f95fa73e8912d8e349d7c0ba71c5bd81c836d
--- src/ngircd/conn.c
+++ src/ngircd/conn.c
@@ -1546,34 +1546,46 @@ static void
 Read_Request( CONN_ID Idx )
 {
 	ssize_t len;
+	size_t readbuf_limit = READBUFFER_LEN;
 	static const unsigned int maxbps = COMMAND_LEN / 2;
-	char readbuf[READBUFFER_LEN];
+	char readbuf[READBUFFER_MAX_LEN];
 	time_t t;
 	CLIENT *c;
 	assert( Idx > NONE );
 	assert( My_Connections[Idx].sock > NONE );
 
-#ifdef ZLIB
-	if ((array_bytes(&My_Connections[Idx].rbuf) >= READBUFFER_LEN) ||
-		(array_bytes(&My_Connections[Idx].zip.rbuf) >= READBUFFER_LEN))
+	/* Make sure that there still exists a CLIENT structure associated
+	 * with this connection and check if this is a server or not: */
+	c = Conn_GetClient(Idx);
+	if (c) {
+		/* Servers do get special read buffer limits, so they can
+		 * process all the messages that are required while peering. */
+		if (Client_Type(c) == CLIENT_SERVER)
+			readbuf_limit = READBUFFER_SLINK_LEN;
+	} else
+		LogDebug("Read request without client (connection %d)!?", Idx);
+
+#ifdef ZLIB
+	if ((array_bytes(&My_Connections[Idx].rbuf) >= readbuf_limit) ||
+		(array_bytes(&My_Connections[Idx].zip.rbuf) >= readbuf_limit))
 #else
-	if (array_bytes(&My_Connections[Idx].rbuf) >= READBUFFER_LEN)
+	if (array_bytes(&My_Connections[Idx].rbuf) >= readbuf_limit)
 #endif
 	{
 		/* Read buffer is full */
 		Log(LOG_ERR,
 		    "Receive buffer space exhausted (connection %d): %d/%d bytes",
-		    Idx, array_bytes(&My_Connections[Idx].rbuf), READBUFFER_LEN);
+		    Idx, array_bytes(&My_Connections[Idx].rbuf), readbuf_limit);
 		Conn_Close(Idx, "Receive buffer space exhausted", NULL, false);
 		return;
 	}
 
 #ifdef SSL_SUPPORT
 	if (Conn_OPTION_ISSET(&My_Connections[Idx], CONN_SSL))
-		len = ConnSSL_Read( &My_Connections[Idx], readbuf, sizeof(readbuf));
+		len = ConnSSL_Read( &My_Connections[Idx], readbuf, readbuf_limit);
 	else
 #endif
-	len = read(My_Connections[Idx].sock, readbuf, sizeof(readbuf));
+	len = read(My_Connections[Idx].sock, readbuf, readbuf_limit);
 	if (len == 0) {
 		LogDebug("Client \"%s:%u\" is closing connection %d ...",
 			 My_Connections[Idx].host,
blob - ff8cd226d641b0dced4b398438b74c14f2df983a
blob + 7ce30e572862f8cd04fb05ced54ec4d072e53e47
--- src/ngircd/defines.h
+++ src/ngircd/defines.h
@@ -153,6 +153,12 @@
 /** Size of the read buffer of a connection in bytes. */
 #define READBUFFER_LEN 2048
 
+/** Maximum size of the read buffer of a connection in bytes. */
+#define READBUFFER_MAX_LEN 65535
+
+/** Maximum size of the read buffer of a server link connection in bytes. */
+#define READBUFFER_SLINK_LEN 65536
+
 /** Size that triggers write buffer flushing if more space is needed. */
 #define WRITEBUFFER_FLUSH_LEN 4096
 
@@ -160,7 +166,7 @@
 #define WRITEBUFFER_MAX_LEN 32768
 
 /** Maximum size of the write buffer of a server link connection in bytes. */
-#define WRITEBUFFER_SLINK_LEN 65536
+#define WRITEBUFFER_SLINK_LEN READBUFFER_SLINK_LEN
 
 
 /* IRC/IRC+ protocol */