Added epoll support on linux (#3798)

Added epoll event dispatching support on linux systems. You can enable it by adding the configure option --enable-epoll Credits to Hercules.
2018-12-26 23:58:04 +01:00
parent 24dad2ee57
commit eb2e40c370
4 changed files with 290 additions and 14 deletions
--- a/src/common/socket.cpp
+++ b/src/common/socket.cpp
@@ -9,22 +9,34 @@
 	#include "winapi.hpp"
 #else
 	#include <errno.h>
-#include <netinet/tcp.h>
-	#include <net/if.h>
-	#include <unistd.h>
-#include <sys/ioctl.h>
-	#include <netdb.h>
 	#include <arpa/inet.h>
+	#include <net/if.h>
+	#include <netdb.h>
+	#include <sys/ioctl.h>
+	#include <sys/socket.h>
+	#include <sys/time.h>
+	#include <unistd.h>
+
+	#if defined(__linux__) || defined(__linux)
+		#include <linux/tcp.h>
+
+		#ifdef SOCKET_EPOLL
+			#include <sys/epoll.h>
+		#endif
+	#else 
+		#include <netinet/in.h>
+		#include <netinet/tcp.h>
+	#endif

 	#ifndef SIOCGIFCONF
-	#include <sys/sockio.h> // SIOCGIFCONF on Solaris, maybe others? [Shinomori]
+		#include <sys/sockio.h> // SIOCGIFCONF on Solaris, maybe others? [Shinomori]
 	#endif
 	#ifndef FIONBIO
-	#include <sys/filio.h> // FIONBIO on Solaris [FlavioJS]
+		#include <sys/filio.h> // FIONBIO on Solaris [FlavioJS]
 	#endif

 	#ifdef HAVE_SETRLIMIT
-	#include <sys/resource.h>
+		#include <sys/resource.h>
 	#endif
 #endif

@@ -203,7 +215,17 @@ char* sErr(int code)
 	#define MSG_NOSIGNAL 0
 #endif

-fd_set readfds;
+#ifndef SOCKET_EPOLL
+	// Select based Event Dispatcher
+	fd_set readfds;
+#else
+	// Epoll based Event Dispatcher
+	static int epoll_maxevents = (FD_SETSIZE / 2);
+	static int epfd = SOCKET_ERROR;
+	static struct epoll_event epevent;
+	static struct epoll_event *epevents = nullptr;
+#endif
+
 int fd_max;
 time_t last_tick;
 time_t stall_time = 60;
@@ -478,8 +500,22 @@ int connect_client(int listen_fd)
 	}
 #endif

-	if( fd_max <= fd ) fd_max = fd + 1;
+#ifndef SOCKET_EPOLL
+	// Select Based Event Dispatcher
 	sFD_SET(fd,&readfds);
+#else
+	// Epoll based Event Dispatcher
+	epevent.data.fd = fd;
+	epevent.events = EPOLLIN;
+
+	if( epoll_ctl( epfd, EPOLL_CTL_ADD, fd, &epevent ) == SOCKET_ERROR ){
+		ShowError( "connect_client: Failed to add to epoll event dispatcher for new socket #%d: %s\n", fd, error_msg() );
+		sClose( fd );
+		return -1;
+	}
+#endif
+
+	if( fd_max <= fd ) fd_max = fd + 1;

 	create_session(fd, recv_to_fifo, send_from_fifo, default_func_parse);
 	session[fd]->client_addr = ntohl(client_address.sin_addr.s_addr);
@@ -531,8 +567,22 @@ int make_listen_bind(uint32 ip, uint16 port)
 		exit(EXIT_FAILURE);
 	}

-	if(fd_max <= fd) fd_max = fd + 1;
+#ifndef SOCKET_EPOLL
+	// Select Based Event Dispatcher
 	sFD_SET(fd, &readfds);
+#else
+	// Epoll based Event Dispatcher
+	epevent.data.fd = fd;
+	epevent.events = EPOLLIN;
+
+	if( epoll_ctl( epfd, EPOLL_CTL_ADD, fd, &epevent ) == SOCKET_ERROR ){
+		ShowError( "make_listen_bind: failed to add listener socket #%d to epoll event dispatcher: %s\n", fd, error_msg() );
+		sClose(fd);
+		exit(EXIT_FAILURE);
+	}
+#endif
+
+	if(fd_max <= fd) fd_max = fd + 1;

 	create_session(fd, connect_client, null_send, null_parse);
 	session[fd]->client_addr = 0; // just listens
@@ -643,8 +693,22 @@ int make_connection(uint32 ip, uint16 port, bool silent,int timeout) {
 	set_nonblocking(fd, 1);
 #endif

-	if (fd_max <= fd) fd_max = fd + 1;
+#ifndef SOCKET_EPOLL
+	// Select Based Event Dispatcher
 	sFD_SET(fd,&readfds);
+#else
+	// Epoll based Event Dispatcher
+	epevent.data.fd = fd;
+	epevent.events = EPOLLIN;
+
+	if( epoll_ctl( epfd, EPOLL_CTL_ADD, fd, &epevent ) == SOCKET_ERROR ){
+		ShowError( "make_connection: failed to add socket #%d to epoll event dispatcher: %s\n", fd, error_msg() );
+		sClose(fd);
+		return -1;
+	}
+#endif
+
+	if (fd_max <= fd) fd_max = fd + 1;

 	create_session(fd, recv_to_fifo, send_from_fifo, default_func_parse);
 	session[fd]->client_addr = ntohl(remote_address.sin_addr.s_addr);
@@ -821,8 +885,10 @@ int WFIFOSET(int fd, size_t len)

 int do_sockets(t_tick next)
 {
+#ifndef SOCKET_EPOLL
 	fd_set rfd;
 	struct timeval timeout;
+#endif
 	int ret,i;

 	// PRESEND Timers are executed before do_sendrecv and can send packets and/or set sessions to eof.
@@ -840,6 +906,9 @@ int do_sockets(t_tick next)
 	}
 #endif

+#ifndef SOCKET_EPOLL
+	// Select based Event Dispatcher
+
 	// can timeout until the next tick
 	timeout.tv_sec  = (long)(next/1000);
 	timeout.tv_usec = (long)(next%1000*1000);
@@ -856,6 +925,20 @@ int do_sockets(t_tick next)
 		}
 		return 0; // interrupted by a signal, just loop and try again
 	}
+#else
+	// Epoll based Event Dispatcher
+
+	ret = epoll_wait( epfd, epevents, epoll_maxevents, next );
+
+	if( ret == SOCKET_ERROR ){
+		if( sErrno != S_EINTR ){
+			ShowFatalError( "do_sockets: epoll_wait() failed, %s!\n", error_msg() );
+			exit( EXIT_FAILURE );
+		}
+
+		return 0; // interrupted by a signal, just loop and try again
+	}
+#endif

 	last_tick = time(NULL);

@@ -867,6 +950,26 @@ int do_sockets(t_tick next)
 		if( session[fd] )
 			session[fd]->func_recv(fd);
 	}
+#elif defined(SOCKET_EPOLL)
+	// epoll based selection
+
+	for( i = 0; i < ret; i++ ){
+		struct epoll_event *it = &epevents[i];
+		int fd = it->data.fd;
+		struct socket_data *sock = session[fd];
+
+		if( !sock ){
+			continue;
+		}
+
+		if( ( it->events & (EPOLLERR|EPOLLHUP) ) || !( it->events & EPOLLIN ) ){
+			// Got Error on this connection
+			set_eof( fd );
+		}else if( it->events & EPOLLIN ){
+			// data waiting
+			sock->func_recv( fd );
+		}
+	}
 #else
 	// otherwise assume that the fd_set is a bit-array and enumerate it in a standard way
 	for( i = 1; ret && i < fd_max; ++i )
@@ -1238,6 +1341,17 @@ int socket_config_read(const char* cfgName)
 			ddos_autoreset = atoi(w2);
 		else if (!strcmpi(w1,"debug"))
 			access_debug = config_switch(w2);
+#ifdef SOCKET_EPOLL
+		else if( !strcmpi( w1, "epoll_maxevents" ) ){
+			epoll_maxevents = atoi(w2);
+
+			// minimum that seems to be useful
+			if( epoll_maxevents < 16 ){
+				ShowWarning( "socket_config_read: epoll_maxevents is set too low. Defaulting to 16...\n" );
+				epoll_maxevents = 16;
+			}
+		}
+#endif
 #endif
 		else if (!strcmpi(w1, "import"))
 			socket_config_read(w2);
@@ -1287,6 +1401,16 @@ void socket_final(void)
 	if( WSACleanup() != 0 ){
 		ShowError("socket_final: WinSock could not be cleaned up! %s\n", error_msg() );
 	}
+#elif defined(SOCKET_EPOLL)
+	if( epfd != SOCKET_ERROR ){
+		sClose(epfd);
+		epfd = SOCKET_ERROR;
+	}
+
+	if( epevents != nullptr ){
+		aFree( epevents );
+		epevents = nullptr;
+	}
 #endif
 }

@@ -1297,7 +1421,17 @@ void do_close(int fd)
 		return;// invalid

 	flush_fifo(fd); // Try to send what's left (although it might not succeed since it's a nonblocking socket)
+
+#ifndef SOCKET_EPOLL
+	// Select based Event Dispatcher
 	sFD_CLR(fd, &readfds);// this needs to be done before closing the socket
+#else
+	// Epoll based Event Dispatcher
+	epevent.data.fd = fd;
+	epevent.events = EPOLLIN;
+	epoll_ctl( epfd, EPOLL_CTL_DEL, fd, &epevent ); // removing the socket from epoll when it's being closed is not required but recommended
+#endif
+
 	sShutdown(fd, SHUT_RDWR); // Disallow further reads/writes
 	sClose(fd); // We don't really care if these closing functions return an error, we are just shutting down and not reusing this socket.
 	if (session[fd]) delete_session(fd);
@@ -1442,7 +1576,25 @@ void socket_init(void)
 	// Get initial local ips
 	naddr_ = socket_getips(addr_,16);

+#ifndef SOCKET_EPOLL
+	// Select based Event Dispatcher:
 	sFD_ZERO(&readfds);
+	ShowInfo( "Server uses '" CL_WHITE "select" CL_RESET "' as event dispatcher\n" );
+#else
+	// Epoll based Event Dispatcher
+	epfd = epoll_create( FD_SETSIZE ); // 2.6.8 or newer ignores the expected socket amount argument
+
+	if( epfd == SOCKET_ERROR ){
+		ShowError( "Failed to create epoll event dispatcher: %s\n", error_msg() );
+		exit( EXIT_FAILURE );
+	}
+
+	memset( &epevent, 0x00, sizeof( struct epoll_event ) );
+	epevents = (struct epoll_event *)aCalloc( epoll_maxevents, sizeof( struct epoll_event ) );
+
+	ShowInfo( "Server uses '" CL_WHITE "epoll" CL_RESET "' with up to " CL_WHITE "%d" CL_RESET " events per cycle as event dispatcher\n", epoll_maxevents );
+#endif
+
 #if defined(SEND_SHORTLIST)
 	memset(send_shortlist_set, 0, sizeof(send_shortlist_set));
 #endif