[2/2] alfred: Switch to epoll for socket handling

diff --git a/alfred.h b/alfred.h
index 2679515..4839c85 100644
--- a/alfred.h
+++ b/alfred.h
@@ -16,9 +16,10 @@ 
 #include <stdbool.h>
 #include <stdint.h>
 #include <time.h>
-#include <sys/select.h>
+#include <sys/epoll.h>
 #include <sys/types.h>
 #include "bitops.h"
+#include "epoll_handle.h"
 #include "list.h"
 #include "packet.h"
 
@@ -30,6 +31,10 @@ 
 #define ALFRED_SOCK_PATH_DEFAULT	"/var/run/alfred.sock"
 #define NO_FILTER			-1
 
+#ifndef __unused
+#define __unused __attribute__((unused))
+#endif
+
 #define FIXED_TLV_LEN(__tlv_type) \
 	htons(sizeof(__tlv_type) - sizeof((__tlv_type).header))
 
@@ -101,9 +106,12 @@  struct interface {
 	alfred_addr address;
 	uint32_t scope_id;
 	char *interface;
+
 	int netsock;
 	int netsock_mcast;
-	int netsock_arp;
+
+	struct epoll_handle netsock_epoll;
+	struct epoll_handle netsock_mcast_epoll;
 
 	struct hashtable_t *server_hash;
 
@@ -124,9 +132,13 @@  struct globals {
 	uint8_t ipv4mode:1;
 	uint8_t force:1;
 
+	int epollfd;
+
 	int check_timerfd;
+	struct epoll_handle check_epoll;
 
 	int unix_sock;
+	struct epoll_handle unix_epoll;
 	const char *unix_path;
 
 	const char *update_command;
@@ -182,7 +194,6 @@  int sync_data(struct globals *globals);
 ssize_t send_alfred_packet(struct globals *globals, struct interface *interface,
 			   const alfred_addr *dest, void *buf, int length);
 /* unix_sock.c */
-int unix_sock_read(struct globals *globals);
 int unix_sock_open_daemon(struct globals *globals);
 int unix_sock_open_client(struct globals *globals);
 int unix_sock_close(struct globals *globals);
@@ -197,9 +208,6 @@  void netsock_close_all(struct globals *globals);
 int netsock_set_interfaces(struct globals *globals, char *interfaces);
 struct interface *netsock_first_interface(struct globals *globals);
 void netsock_reopen(struct globals *globals);
-int netsock_prepare_select(struct globals *globals, fd_set *fds, int maxsock);
-void netsock_check_error(struct globals *globals, fd_set *errfds);
-int netsock_receive_packet(struct globals *globals, fd_set *fds);
 int netsock_own_address(const struct globals *globals,
 			const alfred_addr *address);
 /* util.c */
diff --git a/batadv_querynl.c b/batadv_querynl.c
index 872cb85..7c1b115 100644
--- a/batadv_querynl.c
+++ b/batadv_querynl.c
@@ -26,10 +26,6 @@ 
 #include "batadv_query.h"
 #include "netlink.h"
 
-#ifndef __unused
-#define __unused __attribute__((unused))
-#endif
-
 static const int translate_mac_netlink_mandatory[] = {
 	BATADV_ATTR_TT_ADDRESS,
 	BATADV_ATTR_ORIG_ADDRESS,
diff --git a/epoll_handle.h b/epoll_handle.h
new file mode 100644
index 0000000..4ec69b9
--- /dev/null
+++ b/epoll_handle.h
@@ -0,0 +1,25 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) B.A.T.M.A.N. contributors:
+ *
+ * Sven Eckelmann
+ *
+ * License-Filename: LICENSES/preferred/GPL-2.0
+ */
+
+#ifndef _ALFRED_EPOLL_HANDLE_H
+#define _ALFRED_EPOLL_HANDLE_H
+
+#include <sys/epoll.h>
+
+struct globals;
+struct epoll_handle;
+
+typedef void (*epoll_handler)(struct globals *globals,
+			      struct epoll_handle *handle,
+			      struct epoll_event *ev);
+
+struct epoll_handle {
+	epoll_handler handler;
+};
+
+#endif /* _ALFRED_EPOLL_HANDLE_H */
diff --git a/netsock.c b/netsock.c
index 128e768..feed21d 100644
--- a/netsock.c
+++ b/netsock.c
@@ -20,7 +20,7 @@ 
 #include <stdint.h>
 #include <sys/types.h>
 #include <stdlib.h>
-#include <sys/select.h>
+#include <sys/epoll.h>
 #ifdef CONFIG_ALFRED_CAPABILITIES
 #include <sys/capability.h>
 #endif
@@ -203,12 +203,59 @@  out:
 	return ret;
 }
 
-static int netsock_open(struct interface *interface)
+static void netsock_close_error(struct interface *interface)
+{
+	fprintf(stderr, "Error on netsock detected\n");
+
+	if (interface->netsock >= 0)
+		close(interface->netsock);
+
+	if (interface->netsock_mcast >= 0)
+		close(interface->netsock_mcast);
+
+	interface->netsock = -1;
+	interface->netsock_mcast = -1;
+}
+
+static void netsock_handle_event(struct globals *globals,
+				 struct epoll_handle *handle,
+				 struct epoll_event *ev)
+{
+	struct interface *interface;
+
+	interface = container_of(handle, struct interface, netsock_epoll);
+
+	if (ev->events & EPOLLERR) {
+		netsock_close_error(interface);
+		return;
+	}
+
+	recv_alfred_packet(globals, interface, interface->netsock);
+}
+
+static void netsock_mcast_handle_event(struct globals *globals,
+				       struct epoll_handle *handle,
+				       struct epoll_event *ev)
+{
+	struct interface *interface;
+
+	interface = container_of(handle, struct interface, netsock_mcast_epoll);
+
+	if (ev->events & EPOLLERR) {
+		netsock_close_error(interface);
+		return;
+	}
+
+	recv_alfred_packet(globals, interface, interface->netsock_mcast);
+}
+
+static int netsock_open(struct globals *globals, struct interface *interface)
 {
 	int sock;
 	int sock_mc;
 	struct sockaddr_in6 sin6, sin6_mc;
 	struct ipv6_mreq mreq;
+	struct epoll_event ev;
 	struct ifreq ifr;
 	int ret;
 
@@ -318,6 +365,26 @@  static int netsock_open(struct interface *interface)
 		goto err;
 	}
 
+	ev.events = EPOLLIN;
+	ev.data.ptr = &interface->netsock_epoll;
+	interface->netsock_epoll.handler = netsock_handle_event;
+
+	if (epoll_ctl(globals->epollfd, EPOLL_CTL_ADD, sock,
+		      &ev) == -1) {
+		perror("Failed to add epoll for netsock");
+		goto err;
+	}
+
+	ev.events = EPOLLIN;
+	ev.data.ptr = &interface->netsock_mcast_epoll;
+	interface->netsock_mcast_epoll.handler = netsock_mcast_handle_event;
+
+	if (epoll_ctl(globals->epollfd, EPOLL_CTL_ADD, sock_mc,
+		      &ev) == -1) {
+		perror("Failed to add epoll for netsock_mcast");
+		goto err;
+	}
+
 	interface->netsock = sock;
 	interface->netsock_mcast = sock_mc;
 
@@ -328,11 +395,12 @@  err:
 	return -1;
 }
 
-static int netsock_open4(struct interface *interface)
+static int netsock_open4(struct globals *globals, struct interface *interface)
 {
 	int sock;
 	int sock_mc;
 	struct sockaddr_in sin4, sin_mc;
+	struct epoll_event ev;
 	struct ip_mreq mreq;
 	struct ifreq ifr;
 	int ret;
@@ -446,6 +514,26 @@  static int netsock_open4(struct interface *interface)
 		goto err;
 	}
 
+	ev.events = EPOLLIN;
+	ev.data.ptr = &interface->netsock_epoll;
+	interface->netsock_epoll.handler = netsock_handle_event;
+
+	if (epoll_ctl(globals->epollfd, EPOLL_CTL_ADD, sock,
+		      &ev) == -1) {
+		perror("Failed to add epoll for netsock");
+		goto err;
+	}
+
+	ev.events = EPOLLIN;
+	ev.data.ptr = &interface->netsock_mcast_epoll;
+	interface->netsock_mcast_epoll.handler = netsock_mcast_handle_event;
+
+	if (epoll_ctl(globals->epollfd, EPOLL_CTL_ADD, sock_mc,
+		      &ev) == -1) {
+		perror("Failed to add epoll for netsock_mcast");
+		goto err;
+	}
+
 	interface->netsock = sock;
 	interface->netsock_mcast = sock_mc;
 
@@ -464,9 +552,9 @@  int netsock_open_all(struct globals *globals)
 
 	list_for_each_entry(interface, &globals->interfaces, list) {
 		if (globals->ipv4mode)
-			ret = netsock_open4(interface);
+			ret = netsock_open4(globals, interface);
 		else
-			ret = netsock_open(interface);
+			ret = netsock_open(globals, interface);
 
 		if (ret >= 0)
 			num_socks++;
@@ -493,82 +581,13 @@  void netsock_reopen(struct globals *globals)
 	list_for_each_entry(interface, &globals->interfaces, list) {
 		if (interface->netsock < 0) {
 			if (globals->ipv4mode)
-				netsock_open4(interface);
+				netsock_open4(globals, interface);
 			else
-				netsock_open(interface);
+				netsock_open(globals, interface);
 		}
 	}
 }
 
-int netsock_prepare_select(struct globals *globals, fd_set *fds, int maxsock)
-{
-	struct interface *interface;
-
-	list_for_each_entry(interface, &globals->interfaces, list) {
-		if (interface->netsock >= 0) {
-			FD_SET(interface->netsock, fds);
-			if (maxsock < interface->netsock)
-				maxsock = interface->netsock;
-		}
-
-		if (interface->netsock_mcast >= 0) {
-			FD_SET(interface->netsock_mcast, fds);
-			if (maxsock < interface->netsock_mcast)
-				maxsock = interface->netsock_mcast;
-		}
-	}
-
-	return maxsock;
-}
-
-void netsock_check_error(struct globals *globals, fd_set *errfds)
-{
-	struct interface *interface;
-
-	list_for_each_entry(interface, &globals->interfaces, list) {
-		if ((interface->netsock < 0 ||
-		     !FD_ISSET(interface->netsock, errfds)) &&
-		    (interface->netsock_mcast < 0 ||
-		     !FD_ISSET(interface->netsock_mcast, errfds)))
-			continue;
-
-		fprintf(stderr, "Error on netsock detected\n");
-
-		if (interface->netsock >= 0)
-			close(interface->netsock);
-
-		if (interface->netsock_mcast >= 0)
-			close(interface->netsock_mcast);
-
-		interface->netsock = -1;
-		interface->netsock_mcast = -1;
-	}
-}
-
-int netsock_receive_packet(struct globals *globals, fd_set *fds)
-{
-	struct interface *interface;
-	int recvs = 0;
-
-	list_for_each_entry(interface, &globals->interfaces, list) {
-		if (interface->netsock >= 0 &&
-		    FD_ISSET(interface->netsock, fds)) {
-			recv_alfred_packet(globals, interface,
-					   interface->netsock);
-			recvs++;
-		}
-
-		if (interface->netsock_mcast >= 0 &&
-		    FD_ISSET(interface->netsock_mcast, fds)) {
-			recv_alfred_packet(globals, interface,
-					   interface->netsock_mcast);
-			recvs++;
-		}
-	}
-
-	return recvs;
-}
-
 int netsock_own_address(const struct globals *globals,
 			const alfred_addr *address)
 {
diff --git a/server.c b/server.c
index b5ec7b2..52cdbe7 100644
--- a/server.c
+++ b/server.c
@@ -16,7 +16,7 @@ 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <sys/select.h>
+#include <sys/epoll.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>
 #include <sys/time.h>
@@ -367,9 +367,62 @@  static void execute_update_command(struct globals *globals)
 	free(command);
 }
 
+static void process_events(struct globals *globals)
+{
+	/* WARNING only processing one event because it could be that
+	 * netsock + their fds are getting deleted
+	 */
+	struct epoll_event events[1];
+	struct epoll_handle *handle;
+	int nfds;
+
+	nfds = epoll_wait(globals->epollfd, events,
+			  sizeof(events) / sizeof(*events),  -1);
+	if (nfds == -1) {
+		if (errno == EINTR)
+			return;
+
+		perror("main loop select failed ...");
+		return;
+	}
+
+	for (int i = 0; i < nfds; i++) {
+		handle = (struct epoll_handle *)events[i].data.ptr;
+		handle->handler(globals, handle, &events[i]);
+	}
+}
+
+static void sync_period_timer(struct globals *globals,
+			      struct epoll_handle *handle __unused,
+			      struct epoll_event *ev __unused)
+{
+	struct timespec now;
+	uint64_t timer_exp;
+
+	read(globals->check_timerfd, &timer_exp, sizeof(timer_exp));
+	clock_gettime(CLOCK_MONOTONIC, &now);
+
+	if (globals->opmode == OPMODE_PRIMARY) {
+		/* we are a primary */
+		printf("[%ld.%09ld] announce primary ...\n",
+		       now.tv_sec, now.tv_nsec);
+		announce_primary(globals);
+		sync_data(globals);
+	} else {
+		/* send local data to server */
+		update_server_info(globals);
+		push_local_data(globals);
+	}
+
+	purge_data(globals);
+	check_if_sockets(globals);
+	execute_update_command(globals);
+}
+
 static int create_sync_period_timer(struct globals *globals)
 {
 	struct itimerspec sync_timer;
+	struct epoll_event ev;
 	int ret;
 
 	globals->check_timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);
@@ -387,21 +440,34 @@  static int create_sync_period_timer(struct globals *globals)
 		return -1;
 	}
 
+	ev.events = EPOLLIN;
+	ev.data.ptr = &globals->check_epoll;
+	globals->check_epoll.handler = sync_period_timer;
+
+	if (epoll_ctl(globals->epollfd, EPOLL_CTL_ADD, globals->check_timerfd,
+		      &ev) == -1) {
+		perror("Failed to add epoll for check_timer");
+		return -1;
+	}
+
 	return 0;
 }
 
 int alfred_server(struct globals *globals)
 {
-	int maxsock, ret, recvs;
-	struct timespec now;
-	fd_set fds, errfds;
 	size_t num_interfaces;
-	uint64_t timer_exp;
+	struct timespec now;
 	int num_socks;
 
 	if (create_hashes(globals))
 		return -1;
 
+	globals->epollfd = epoll_create1(0);
+	if (globals->epollfd == -1) {
+		perror("Could not create epoll for main thread");
+		return -1;
+	}
+
 	if (create_sync_period_timer(globals))
 		return -1;
 
@@ -447,56 +513,7 @@  int alfred_server(struct globals *globals)
 
 	while (1) {
 		netsock_reopen(globals);
-
-		FD_ZERO(&fds);
-		FD_ZERO(&errfds);
-		FD_SET(globals->unix_sock, &fds);
-		maxsock = globals->unix_sock;
-
-		FD_SET(globals->check_timerfd, &fds);
-		if (maxsock < globals->check_timerfd)
-			maxsock = globals->check_timerfd;
-
-		maxsock = netsock_prepare_select(globals, &fds, maxsock);
-		maxsock = netsock_prepare_select(globals, &errfds, maxsock);
-
-		ret = pselect(maxsock + 1, &fds, NULL, &errfds, NULL, NULL);
-
-		if (ret == -1) {
-			perror("main loop select failed ...");
-		} else if (ret) {
-			netsock_check_error(globals, &errfds);
-
-			if (FD_ISSET(globals->unix_sock, &fds)) {
-				unix_sock_read(globals);
-				continue;
-			} else {
-				recvs = netsock_receive_packet(globals, &fds);
-				if (recvs > 0)
-					continue;
-			}
-		}
-
-		if (FD_ISSET(globals->check_timerfd, &fds)) {
-			read(globals->check_timerfd, &timer_exp,
-			     sizeof(timer_exp));
-			clock_gettime(CLOCK_MONOTONIC, &now);
-
-			if (globals->opmode == OPMODE_PRIMARY) {
-				/* we are a primary */
-				printf("[%ld.%09ld] announce primary ...\n",
-				       now.tv_sec, now.tv_nsec);
-				announce_primary(globals);
-				sync_data(globals);
-			} else {
-				/* send local data to server */
-				update_server_info(globals);
-				push_local_data(globals);
-			}
-			purge_data(globals);
-			check_if_sockets(globals);
-			execute_update_command(globals);
-		}
+		process_events(globals);
 	}
 
 	netsock_close_all(globals);
diff --git a/unix_sock.c b/unix_sock.c
index 3894736..ef72aa0 100644
--- a/unix_sock.c
+++ b/unix_sock.c
@@ -23,9 +23,14 @@ 
 #include "hash.h"
 #include "packet.h"
 
+static void unix_sock_read(struct globals *globals,
+			   struct epoll_handle *handle __unused,
+			   struct epoll_event *ev __unused);
+
 int unix_sock_open_daemon(struct globals *globals)
 {
 	struct sockaddr_un addr;
+	struct epoll_event ev;
 
 	unlink(globals->unix_path);
 
@@ -51,6 +56,16 @@  int unix_sock_open_daemon(struct globals *globals)
 		return -1;
 	}
 
+	ev.events = EPOLLIN;
+	ev.data.ptr = &globals->unix_epoll;
+	globals->unix_epoll.handler = unix_sock_read;
+
+	if (epoll_ctl(globals->epollfd, EPOLL_CTL_ADD, globals->unix_sock,
+		      &ev) == -1) {
+		perror("Failed to add epoll for check_timer");
+		return -1;
+	}
+
 	return 0;
 }
 
@@ -472,20 +487,22 @@  err:
 	return ret;
 }
 
-int unix_sock_read(struct globals *globals)
+static void unix_sock_read(struct globals *globals,
+			   struct epoll_handle *handle __unused,
+			   struct epoll_event *ev __unused)
 {
 	int client_sock;
 	struct sockaddr_un sun_addr;
 	socklen_t sun_size = sizeof(sun_addr);
 	struct alfred_tlv *packet;
 	uint8_t buf[MAX_PAYLOAD];
-	int length, headsize, ret = -1;
+	int length, headsize;
 
 	client_sock = accept(globals->unix_sock, (struct sockaddr *)&sun_addr,
 			     &sun_size);
 	if (client_sock < 0) {
 		perror("can't accept unix connection");
-		return -1;
+		return;
 	}
 
 	/* we assume that we can instantly read here. */
@@ -510,44 +527,42 @@  int unix_sock_read(struct globals *globals)
 
 	switch (packet->type) {
 	case ALFRED_PUSH_DATA:
-		ret = unix_sock_add_data(globals,
-					 (struct alfred_push_data_v0 *)packet,
-					 client_sock);
+		unix_sock_add_data(globals,
+				   (struct alfred_push_data_v0 *)packet,
+				   client_sock);
 		break;
 	case ALFRED_REQUEST:
-		ret = unix_sock_req_data(globals,
-					 (struct alfred_request_v0 *)packet,
-					 client_sock);
+		unix_sock_req_data(globals,
+				   (struct alfred_request_v0 *)packet,
+				   client_sock);
 		break;
 	case ALFRED_MODESWITCH:
-		ret = unix_sock_modesw(globals,
-				       (struct alfred_modeswitch_v0 *)packet,
-				       client_sock);
+		unix_sock_modesw(globals,
+				 (struct alfred_modeswitch_v0 *)packet,
+				 client_sock);
 		break;
 	case ALFRED_CHANGE_INTERFACE:
-		ret = unix_sock_change_iface(globals,
-					     (struct alfred_change_interface_v0 *)packet,
-					     client_sock);
+		 unix_sock_change_iface(globals,
+					(struct alfred_change_interface_v0 *)packet,
+					client_sock);
 		break;
 	case ALFRED_CHANGE_BAT_IFACE:
-		ret = unix_sock_change_bat_iface(globals,
-						 (struct alfred_change_bat_iface_v0 *)packet,
-						 client_sock);
+		unix_sock_change_bat_iface(globals,
+					   (struct alfred_change_bat_iface_v0 *)packet,
+					   client_sock);
 		break;
 	case ALFRED_SERVER_STATUS:
-		ret = unix_sock_server_status(globals, client_sock);
+		unix_sock_server_status(globals, client_sock);
 		break;
 	default:
 		/* unknown packet type */
-		ret = -1;
 		goto err;
 	}
 
-	return ret;
+	return;
 
 err:
 	close(client_sock);
-	return ret;
 }
 
 int unix_sock_close(struct globals *globals)