renamed interface.c to client.c

I don't believe "interface" is a good name for something like
"connection by a client to MPD", let's call it "client".  This is the
first patch in the series which changes the name, beginning with the
file name.

1 files changed, 797 insertions, 0 deletions

diff --git a/src/client.c b/src/client.c
new file mode 100644
index 000000000..91c055699
--- /dev/null
+++ b/src/client.c
@@ -0,0 +1,797 @@
+/* the Music Player Daemon (MPD)
+ * Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
+ * This project's homepage is: http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "client.h"
+#include "command.h"
+#include "conf.h"
+#include "log.h"
+#include "listen.h"
+#include "permission.h"
+#include "sllist.h"
+#include "utils.h"
+#include "ioops.h"
+#include "myfprintf.h"
+#include "os_compat.h"
+#include "main_notify.h"
+
+#include "../config.h"
+
+#define GREETING				"OK MPD " PROTOCOL_VERSION "\n"
+
+#define INTERFACE_MAX_BUFFER_LENGTH			(40960)
+#define INTERFACE_LIST_MODE_BEGIN			"command_list_begin"
+#define INTERFACE_LIST_OK_MODE_BEGIN			"command_list_ok_begin"
+#define INTERFACE_LIST_MODE_END				"command_list_end"
+#define INTERFACE_DEFAULT_OUT_BUFFER_SIZE		(4096)
+#define INTERFACE_TIMEOUT_DEFAULT			(60)
+#define INTERFACE_MAX_CONNECTIONS_DEFAULT		(10)
+#define INTERFACE_MAX_COMMAND_LIST_DEFAULT		(2048*1024)
+#define INTERFACE_MAX_OUTPUT_BUFFER_SIZE_DEFAULT	(8192*1024)
+
+/* set this to zero to indicate we have no possible interfaces */
+static unsigned int interface_max_connections;	/*INTERFACE_MAX_CONNECTIONS_DEFAULT; */
+static int interface_timeout = INTERFACE_TIMEOUT_DEFAULT;
+static size_t interface_max_command_list_size =
+    INTERFACE_MAX_COMMAND_LIST_DEFAULT;
+static size_t interface_max_output_buffer_size =
+    INTERFACE_MAX_OUTPUT_BUFFER_SIZE_DEFAULT;
+
+/* maybe make conf option for this, or... 32 might be good enough */
+static long int interface_list_cache_size = 32;
+
+/* shared globally between all interfaces: */
+static struct strnode *list_cache;
+static struct strnode *list_cache_head;
+static struct strnode *list_cache_tail;
+
+typedef struct _Interface {
+	char buffer[INTERFACE_MAX_BUFFER_LENGTH];
+	size_t bufferLength;
+	size_t bufferPos;
+	int fd;	/* file descriptor */
+	int permission;
+	time_t lastTime;
+	struct strnode *cmd_list;	/* for when in list mode */
+	struct strnode *cmd_list_tail;	/* for when in list mode */
+	int cmd_list_OK;	/* print OK after each command execution */
+	size_t cmd_list_size;	/* mem cmd_list consumes */
+	int cmd_list_dup;	/* has the cmd_list been copied to private space? */
+	struct sllnode *deferred_send;	/* for output if client is slow */
+	size_t deferred_bytes;	/* mem deferred_send consumes */
+	int expired;	/* set whether this interface should be closed on next
+			   check of old interfaces */
+	unsigned int num;	/* interface number */
+
+	char *send_buf;
+	size_t send_buf_used;	/* bytes used this instance */
+	size_t send_buf_size;	/* bytes usable this instance */
+	size_t send_buf_alloc;	/* bytes actually allocated */
+} Interface;
+
+static Interface *interfaces;
+
+static void flushInterfaceBuffer(Interface * interface);
+
+static void printInterfaceOutBuffer(Interface * interface);
+
+#ifdef SO_SNDBUF
+static size_t get_default_snd_buf_size(Interface * interface)
+{
+	int new_size;
+	socklen_t sockOptLen = sizeof(int);
+
+	if (getsockopt(interface->fd, SOL_SOCKET, SO_SNDBUF,
+		       (char *)&new_size, &sockOptLen) < 0) {
+		DEBUG("problem getting sockets send buffer size\n");
+		return INTERFACE_DEFAULT_OUT_BUFFER_SIZE;
+	}
+	if (new_size > 0)
+		return (size_t)new_size;
+	DEBUG("sockets send buffer size is not positive\n");
+	return INTERFACE_DEFAULT_OUT_BUFFER_SIZE;
+}
+#else /* !SO_SNDBUF */
+static size_t get_default_snd_buf_size(Interface * interface)
+{
+	return INTERFACE_DEFAULT_OUT_BUFFER_SIZE;
+}
+#endif /* !SO_SNDBUF */
+
+static void set_send_buf_size(Interface * interface)
+{
+	size_t new_size = get_default_snd_buf_size(interface);
+	if (interface->send_buf_size != new_size) {
+		interface->send_buf_size = new_size;
+		/* don't resize to get smaller, only bigger */
+		if (interface->send_buf_alloc < new_size) {
+			if (interface->send_buf)
+				free(interface->send_buf);
+			interface->send_buf = xmalloc(new_size);
+			interface->send_buf_alloc = new_size;
+		}
+	}
+}
+
+static void openInterface(Interface * interface, int fd)
+{
+	assert(interface->fd < 0);
+
+	interface->cmd_list_size = 0;
+	interface->cmd_list_dup = 0;
+	interface->cmd_list_OK = -1;
+	interface->bufferLength = 0;
+	interface->bufferPos = 0;
+	interface->fd = fd;
+	set_nonblocking(fd);
+	interface->lastTime = time(NULL);
+	interface->cmd_list = NULL;
+	interface->cmd_list_tail = NULL;
+	interface->deferred_send = NULL;
+	interface->expired = 0;
+	interface->deferred_bytes = 0;
+	interface->send_buf_used = 0;
+
+	interface->permission = getDefaultPermissions();
+	set_send_buf_size(interface);
+
+	xwrite(fd, GREETING, strlen(GREETING));
+}
+
+static void free_cmd_list(struct strnode *list)
+{
+	struct strnode *tmp = list;
+
+	while (tmp) {
+		struct strnode *next = tmp->next;
+		if (tmp >= list_cache_head && tmp <= list_cache_tail) {
+			/* inside list_cache[] array */
+			tmp->data = NULL;
+			tmp->next = NULL;
+		} else
+			free(tmp);
+		tmp = next;
+	}
+}
+
+static void cmd_list_clone(Interface * interface)
+{
+	struct strnode *new = dup_strlist(interface->cmd_list);
+	free_cmd_list(interface->cmd_list);
+	interface->cmd_list = new;
+	interface->cmd_list_dup = 1;
+
+	/* new tail */
+	while (new && new->next)
+		new = new->next;
+	interface->cmd_list_tail = new;
+}
+
+static void new_cmd_list_ptr(Interface * interface, char *s, const int size)
+{
+	int i;
+	struct strnode *new;
+
+	if (!interface->cmd_list_dup) {
+		for (i = interface_list_cache_size - 1; i >= 0; --i) {
+			if (list_cache[i].data)
+				continue;
+			new = &(list_cache[i]);
+			new->data = s;
+			/* implied in free_cmd_list() and init: */
+			/* last->next->next = NULL; */
+			goto out;
+		}
+	}
+
+	/* allocate from the heap */
+	new = interface->cmd_list_dup ? new_strnode_dup(s, size)
+	                              : new_strnode(s);
+out:
+	if (interface->cmd_list) {
+		interface->cmd_list_tail->next = new;
+		interface->cmd_list_tail = new;
+	} else
+		interface->cmd_list = interface->cmd_list_tail = new;
+}
+
+static void closeInterface(Interface * interface)
+{
+	struct sllnode *buf;
+	if (interface->fd < 0)
+		return;
+	xclose(interface->fd);
+	interface->fd = -1;
+
+	if (interface->cmd_list) {
+		free_cmd_list(interface->cmd_list);
+		interface->cmd_list = NULL;
+	}
+
+	if ((buf = interface->deferred_send)) {
+		do {
+			struct sllnode *prev = buf;
+			buf = buf->next;
+			free(prev);
+		} while (buf);
+		interface->deferred_send = NULL;
+	}
+
+	SECURE("interface %i: closed\n", interface->num);
+}
+
+void openAInterface(int fd, const struct sockaddr *addr)
+{
+	unsigned int i;
+
+	for (i = 0; i < interface_max_connections
+	     && interfaces[i].fd >= 0; i++) /* nothing */ ;
+
+	if (i == interface_max_connections) {
+		ERROR("Max Connections Reached!\n");
+		xclose(fd);
+	} else {
+		const char *hostname;
+		switch (addr->sa_family) {
+#ifdef HAVE_TCP
+		case AF_INET:
+			hostname = (const char *)inet_ntoa(((const struct sockaddr_in *)
+			                                    addr)->sin_addr);
+			if (!hostname)
+				hostname = "error getting ipv4 address";
+			break;
+#ifdef HAVE_IPV6
+		case AF_INET6:
+			{
+				static char host[INET6_ADDRSTRLEN + 1];
+				memset(host, 0, INET6_ADDRSTRLEN + 1);
+				if (inet_ntop(AF_INET6, (const void *)
+					      &(((const struct sockaddr_in6 *)addr)->
+						sin6_addr), host,
+					      INET6_ADDRSTRLEN)) {
+					hostname = (const char *)host;
+				} else {
+					hostname = "error getting ipv6 address";
+				}
+			}
+			break;
+#endif
+#endif /* HAVE_TCP */
+#ifdef HAVE_UN
+		case AF_UNIX:
+			hostname = "local connection";
+			break;
+#endif /* HAVE_UN */
+		default:
+			hostname = "unknown";
+		}
+		SECURE("interface %i: opened from %s\n", i, hostname);
+		openInterface(&(interfaces[i]), fd);
+	}
+}
+
+static int processLineOfInput(Interface * interface)
+{
+	int ret = 1;
+	char *line = interface->buffer + interface->bufferPos;
+
+	if (interface->cmd_list_OK >= 0) {
+		if (strcmp(line, INTERFACE_LIST_MODE_END) == 0) {
+			DEBUG("interface %i: process command "
+			      "list\n", interface->num);
+			ret = processListOfCommands(interface->fd,
+						    &(interface->permission),
+						    &(interface->expired),
+						    interface->cmd_list_OK,
+						    interface->cmd_list);
+			DEBUG("interface %i: process command "
+			      "list returned %i\n", interface->num, ret);
+			if (ret == 0)
+				commandSuccess(interface->fd);
+			else if (ret == COMMAND_RETURN_CLOSE
+				 || interface->expired)
+				closeInterface(interface);
+
+			printInterfaceOutBuffer(interface);
+			free_cmd_list(interface->cmd_list);
+			interface->cmd_list = NULL;
+			interface->cmd_list_OK = -1;
+		} else {
+			size_t len = strlen(line) + 1;
+			interface->cmd_list_size += len;
+			if (interface->cmd_list_size >
+			    interface_max_command_list_size) {
+				ERROR("interface %i: command "
+				      "list size (%lu) is "
+				      "larger than the max "
+				      "(%lu)\n",
+				      interface->num,
+				      (unsigned long)interface->cmd_list_size,
+				      (unsigned long)
+				      interface_max_command_list_size);
+				closeInterface(interface);
+				ret = COMMAND_RETURN_CLOSE;
+			} else
+				new_cmd_list_ptr(interface, line, len);
+		}
+	} else {
+		if (strcmp(line, INTERFACE_LIST_MODE_BEGIN) == 0) {
+			interface->cmd_list_OK = 0;
+			ret = 1;
+		} else if (strcmp(line, INTERFACE_LIST_OK_MODE_BEGIN) == 0) {
+			interface->cmd_list_OK = 1;
+			ret = 1;
+		} else {
+			DEBUG("interface %i: process command \"%s\"\n",
+			      interface->num, line);
+			ret = processCommand(interface->fd,
+					     &(interface->permission), line);
+			DEBUG("interface %i: command returned %i\n",
+			      interface->num, ret);
+			if (ret == 0)
+				commandSuccess(interface->fd);
+			else if (ret == COMMAND_RETURN_CLOSE
+				 || interface->expired) {
+				closeInterface(interface);
+			}
+			printInterfaceOutBuffer(interface);
+		}
+	}
+
+	return ret;
+}
+
+static int processBytesRead(Interface * interface, int bytesRead)
+{
+	int ret = 0;
+	char *buf_tail = &(interface->buffer[interface->bufferLength - 1]);
+
+	while (bytesRead > 0) {
+		interface->bufferLength++;
+		bytesRead--;
+		buf_tail++;
+		if (*buf_tail == '\n') {
+			*buf_tail = '\0';
+			if (interface->bufferLength > interface->bufferPos) {
+				if (*(buf_tail - 1) == '\r')
+					*(buf_tail - 1) = '\0';
+			}
+			ret = processLineOfInput(interface);
+			if (interface->expired)
+				return ret;
+			interface->bufferPos = interface->bufferLength;
+		}
+		if (interface->bufferLength == INTERFACE_MAX_BUFFER_LENGTH) {
+			if (interface->bufferPos == 0) {
+				ERROR("interface %i: buffer overflow\n",
+				      interface->num);
+				closeInterface(interface);
+				return 1;
+			}
+			if (interface->cmd_list_OK >= 0 &&
+			    interface->cmd_list &&
+			    !interface->cmd_list_dup)
+				cmd_list_clone(interface);
+			assert(interface->bufferLength >= interface->bufferPos
+			       && "bufferLength >= bufferPos");
+			interface->bufferLength -= interface->bufferPos;
+			memmove(interface->buffer,
+				interface->buffer + interface->bufferPos,
+				interface->bufferLength);
+			interface->bufferPos = 0;
+		}
+		if (ret == COMMAND_RETURN_KILL || ret == COMMAND_RETURN_CLOSE) {
+			return ret;
+		}
+
+	}
+
+	return ret;
+}
+
+static int interfaceReadInput(Interface * interface)
+{
+	int bytesRead;
+
+	bytesRead = read(interface->fd,
+			 interface->buffer + interface->bufferLength,
+			 INTERFACE_MAX_BUFFER_LENGTH - interface->bufferLength);
+
+	if (bytesRead > 0)
+		return processBytesRead(interface, bytesRead);
+	else if (bytesRead == 0 || (bytesRead < 0 && errno != EINTR)) {
+		closeInterface(interface);
+	} else
+		return 0;
+
+	return 1;
+}
+
+static void addInterfacesReadyToReadAndListenSocketToFdSet(fd_set * fds,
+							   int *fdmax)
+{
+	unsigned int i;
+
+	FD_ZERO(fds);
+	addListenSocketsToFdSet(fds, fdmax);
+
+	for (i = 0; i < interface_max_connections; i++) {
+		if (interfaces[i].fd >= 0 && !interfaces[i].expired
+		    && !interfaces[i].deferred_send) {
+			FD_SET(interfaces[i].fd, fds);
+			if (*fdmax < interfaces[i].fd)
+				*fdmax = interfaces[i].fd;
+		}
+	}
+}
+
+static void addInterfacesForBufferFlushToFdSet(fd_set * fds, int *fdmax)
+{
+	unsigned int i;
+
+	FD_ZERO(fds);
+
+	for (i = 0; i < interface_max_connections; i++) {
+		if (interfaces[i].fd >= 0 && !interfaces[i].expired
+		    && interfaces[i].deferred_send) {
+			FD_SET(interfaces[i].fd, fds);
+			if (*fdmax < interfaces[i].fd)
+				*fdmax = interfaces[i].fd;
+		}
+	}
+}
+
+static void closeNextErroredInterface(void)
+{
+	fd_set fds;
+	struct timeval tv;
+	unsigned int i;
+
+	tv.tv_sec = 0;
+	tv.tv_usec = 0;
+
+	for (i = 0; i < interface_max_connections; i++) {
+		if (interfaces[i].fd >= 0) {
+			FD_ZERO(&fds);
+			FD_SET(interfaces[i].fd, &fds);
+			if (select(interfaces[i].fd + 1,
+			           &fds, NULL, NULL, &tv) < 0) {
+				closeInterface(&interfaces[i]);
+				return;
+			}
+		}
+	}
+}
+
+int doIOForInterfaces(void)
+{
+	fd_set rfds;
+	fd_set wfds;
+	fd_set efds;
+	unsigned int i;
+	int selret;
+	int fdmax;
+
+	while (1) {
+		fdmax = 0;
+
+		FD_ZERO( &efds );
+		addInterfacesReadyToReadAndListenSocketToFdSet(&rfds, &fdmax);
+		addInterfacesForBufferFlushToFdSet(&wfds, &fdmax);
+
+		registered_IO_add_fds(&fdmax, &rfds, &wfds, &efds);
+
+		main_notify_lock();
+		selret = select(fdmax + 1, &rfds, &wfds, &efds, NULL);
+		main_notify_unlock();
+
+		if (selret < 0 && errno == EINTR)
+			break;
+
+		registered_IO_consume_fds(&selret, &rfds, &wfds, &efds);
+
+		if (selret == 0)
+			break;
+
+		if (selret < 0) {
+			closeNextErroredInterface();
+			continue;
+		}
+
+		getConnections(&rfds);
+
+		for (i = 0; i < interface_max_connections; i++) {
+			if (interfaces[i].fd >= 0
+			    && FD_ISSET(interfaces[i].fd, &rfds)) {
+				if (COMMAND_RETURN_KILL ==
+				    interfaceReadInput(&(interfaces[i]))) {
+					return COMMAND_RETURN_KILL;
+				}
+				interfaces[i].lastTime = time(NULL);
+			}
+			if (interfaces[i].fd >= 0
+			    && FD_ISSET(interfaces[i].fd, &wfds)) {
+				flushInterfaceBuffer(&interfaces[i]);
+				interfaces[i].lastTime = time(NULL);
+			}
+		}
+
+		break;
+	}
+
+	return 1;
+}
+
+void initInterfaces(void)
+{
+	unsigned int i;
+	char *test;
+	ConfigParam *param;
+
+	param = getConfigParam(CONF_CONN_TIMEOUT);
+
+	if (param) {
+		interface_timeout = strtol(param->value, &test, 10);
+		if (*test != '\0' || interface_timeout <= 0) {
+			FATAL("connection timeout \"%s\" is not a positive "
+			      "integer, line %i\n", CONF_CONN_TIMEOUT,
+			      param->line);
+		}
+	}
+
+	param = getConfigParam(CONF_MAX_CONN);
+
+	if (param) {
+		interface_max_connections = strtol(param->value, &test, 10);
+		if (*test != '\0' || interface_max_connections <= 0) {
+			FATAL("max connections \"%s\" is not a positive integer"
+			      ", line %i\n", param->value, param->line);
+		}
+	} else
+		interface_max_connections = INTERFACE_MAX_CONNECTIONS_DEFAULT;
+
+	param = getConfigParam(CONF_MAX_COMMAND_LIST_SIZE);
+
+	if (param) {
+		long tmp = strtol(param->value, &test, 10);
+		if (*test != '\0' || tmp <= 0) {
+			FATAL("max command list size \"%s\" is not a positive "
+			      "integer, line %i\n", param->value, param->line);
+		}
+		interface_max_command_list_size = tmp * 1024;
+	}
+
+	param = getConfigParam(CONF_MAX_OUTPUT_BUFFER_SIZE);
+
+	if (param) {
+		long tmp = strtol(param->value, &test, 10);
+		if (*test != '\0' || tmp <= 0) {
+			FATAL("max output buffer size \"%s\" is not a positive "
+			      "integer, line %i\n", param->value, param->line);
+		}
+		interface_max_output_buffer_size = tmp * 1024;
+	}
+
+	interfaces = xmalloc(sizeof(Interface) * interface_max_connections);
+
+	list_cache = xcalloc(interface_list_cache_size, sizeof(struct strnode));
+	list_cache_head = &(list_cache[0]);
+	list_cache_tail = &(list_cache[interface_list_cache_size - 1]);
+
+	for (i = 0; i < interface_max_connections; i++) {
+		interfaces[i].fd = -1;
+		interfaces[i].send_buf = NULL;
+		interfaces[i].send_buf_size = 0;
+		interfaces[i].send_buf_alloc = 0;
+		interfaces[i].num = i;
+	}
+}
+
+static void closeAllInterfaces(void)
+{
+	unsigned int i;
+
+	for (i = 0; i < interface_max_connections; i++) {
+		if (interfaces[i].fd >= 0)
+			closeInterface(&(interfaces[i]));
+		if (interfaces[i].send_buf)
+			free(interfaces[i].send_buf);
+	}
+	free(list_cache);
+}
+
+void freeAllInterfaces(void)
+{
+	closeAllInterfaces();
+
+	free(interfaces);
+
+	interface_max_connections = 0;
+}
+
+void closeOldInterfaces(void)
+{
+	unsigned int i;
+
+	for (i = 0; i < interface_max_connections; i++) {
+		if (interfaces[i].fd >= 0) {
+			if (interfaces[i].expired) {
+				DEBUG("interface %i: expired\n", i);
+				closeInterface(&(interfaces[i]));
+			} else if (time(NULL) - interfaces[i].lastTime >
+				   interface_timeout) {
+				DEBUG("interface %i: timeout\n", i);
+				closeInterface(&(interfaces[i]));
+			}
+		}
+	}
+}
+
+static void flushInterfaceBuffer(Interface * interface)
+{
+	struct sllnode *buf;
+	ssize_t ret = 0;
+
+	buf = interface->deferred_send;
+	while (buf) {
+		ret = write(interface->fd, buf->data, buf->size);
+		if (ret < 0)
+			break;
+		else if ((size_t)ret < buf->size) {
+			assert(interface->deferred_bytes >= (size_t)ret);
+			interface->deferred_bytes -= ret;
+			buf->data = (char *)buf->data + ret;
+			buf->size -= ret;
+		} else {
+			struct sllnode *tmp = buf;
+			size_t decr = (buf->size + sizeof(struct sllnode));
+
+			assert(interface->deferred_bytes >= decr);
+			interface->deferred_bytes -= decr;
+			buf = buf->next;
+			free(tmp);
+			interface->deferred_send = buf;
+		}
+		interface->lastTime = time(NULL);
+	}
+
+	if (!interface->deferred_send) {
+		DEBUG("interface %i: buffer empty %lu\n", interface->num,
+		      (unsigned long)interface->deferred_bytes);
+		assert(interface->deferred_bytes == 0);
+	} else if (ret < 0 && errno != EAGAIN && errno != EINTR) {
+		/* cause interface to close */
+		DEBUG("interface %i: problems flushing buffer\n",
+		      interface->num);
+		buf = interface->deferred_send;
+		do {
+			struct sllnode *prev = buf;
+			buf = buf->next;
+			free(prev);
+		} while (buf);
+		interface->deferred_send = NULL;
+		interface->deferred_bytes = 0;
+		interface->expired = 1;
+	}
+}
+
+int interfacePrintWithFD(int fd, const char *buffer, size_t buflen)
+{
+	static unsigned int i;
+	size_t copylen;
+	Interface *interface;
+
+	assert(fd >= 0);
+
+	if (i >= interface_max_connections ||
+	    interfaces[i].fd < 0 || interfaces[i].fd != fd) {
+		for (i = 0; i < interface_max_connections; i++) {
+			if (interfaces[i].fd == fd)
+				break;
+		}
+		if (i == interface_max_connections)
+			return -1;
+	}
+
+	/* if fd isn't found or interfaces is going to be closed, do nothing */
+	if (interfaces[i].expired)
+		return 0;
+
+	interface = interfaces + i;
+
+	while (buflen > 0 && !interface->expired) {
+		size_t left;
+
+		assert(interface->send_buf_size >= interface->send_buf_used);
+		left = interface->send_buf_size - interface->send_buf_used;
+
+		copylen = buflen > left ? left : buflen;
+		memcpy(interface->send_buf + interface->send_buf_used, buffer,
+		       copylen);
+		buflen -= copylen;
+		interface->send_buf_used += copylen;
+		buffer += copylen;
+		if (interface->send_buf_used >= interface->send_buf_size)
+			printInterfaceOutBuffer(interface);
+	}
+
+	return 0;
+}
+
+static void printInterfaceOutBuffer(Interface * interface)
+{
+	ssize_t ret;
+	struct sllnode *buf;
+
+	if (interface->fd < 0 || interface->expired ||
+	    !interface->send_buf_used)
+		return;
+
+	if ((buf = interface->deferred_send)) {
+		interface->deferred_bytes += sizeof(struct sllnode)
+		                             + interface->send_buf_used;
+		if (interface->deferred_bytes >
+		    interface_max_output_buffer_size) {
+			ERROR("interface %i: output buffer size (%lu) is "
+			      "larger than the max (%lu)\n",
+			      interface->num,
+			      (unsigned long)interface->deferred_bytes,
+			      (unsigned long)interface_max_output_buffer_size);
+			/* cause interface to close */
+			interface->expired = 1;
+			do {
+				struct sllnode *prev = buf;
+				buf = buf->next;
+				free(prev);
+			} while (buf);
+			interface->deferred_send = NULL;
+			interface->deferred_bytes = 0;
+		} else {
+			while (buf->next)
+				buf = buf->next;
+			buf->next = new_sllnode(interface->send_buf,
+						interface->send_buf_used);
+		}
+	} else {
+		if ((ret = write(interface->fd, interface->send_buf,
+				 interface->send_buf_used)) < 0) {
+			if (errno == EAGAIN || errno == EINTR) {
+				interface->deferred_send =
+				    new_sllnode(interface->send_buf,
+						interface->send_buf_used);
+			} else {
+				DEBUG("interface %i: problems writing\n",
+				      interface->num);
+				interface->expired = 1;
+				return;
+			}
+		} else if ((size_t)ret < interface->send_buf_used) {
+			interface->deferred_send =
+			    new_sllnode(interface->send_buf + ret,
+					interface->send_buf_used - ret);
+		}
+		if (interface->deferred_send) {
+			DEBUG("interface %i: buffer created\n", interface->num);
+			interface->deferred_bytes =
+			    interface->deferred_send->size
+			    + sizeof(struct sllnode);
+		}
+	}
+
+	interface->send_buf_used = 0;
+}
+