bpfcountd: adding initial package

bpfcountd was created to obtain packet statistics in larger networks
without stressing the cpu resources. bpfcountd will count the amount
of packages and bytes over time (for each defined rule). The rules
are defined using the tcpdump filter syntax (bpf). The collected
data is provided on unix socket in plaintext.

Signed-off-by: Linus Lüssing <[email protected]>

package/bpfcountd/Makefile

@@ -0,0 +1,34 @@
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=bpfcountd
+PKG_SOURCE_DATE:=2020-01-01
+PKG_SOURCE_PROTO:=git
+PKG_SOURCE_URL=https://github.com/lemoer/bpfcountd.git
+PKG_SOURCE_VERSION:=9f602a1e8e691749ca233ede06846c7e53623bc5
+
+PKG_BUILD_DEPENDS += libpcap
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/bpfcountd
+  SECTION:=net
+  CATEGORY:=Network
+  TITLE:=Berkeley Packet Filter Counting Daemon
+  DEPENDS:= +libpcap
+endef
+
+define Package/bpfcountd/description
+	bpfcountd was created to obtain packet statistics in larger networks
+	without stressing the cpu resources. bpfcountd will count the amount
+	of packages and bytes over time (for each defined rule). The rules
+	are defined using the tcpdump filter syntax (bpf). The collected
+	data is provided on unix socket in plaintext.
+endef
+
+define Package/bpfcountd/install
+	$(INSTALL_DIR) $(1)/usr/sbin
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/bpfcountd $(1)/usr/sbin/
+	$(CP) ./files/* $(1)/
+endef
+
+$(eval $(call BuildPackage,bpfcountd))

package/bpfcountd/files/etc/bpfcountd.filters

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+arp;arp
+icmp6;icmp6

package/bpfcountd/files/etc/config/bpfcountd

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+config bpfcountd 'eth0_in'
+	option ifname 'eth0'
+	option prefilter 'inbound'
+	option filterfile '/etc/bpfcountd.filters'
+	option disabled '1'
+
+
+config bpfcountd 'eth0_out'
+	option ifname 'eth0'
+	option prefilter 'outbound'
+	option filterfile '/etc/bpfcountd.filters'
+	option disabled '1'

package/bpfcountd/files/etc/init.d/bpfcountd

@@ -0,0 +1,89 @@
+#!/bin/sh /etc/rc.common
+
+USE_PROCD=1
+START=20
+STOP=90
+
+UNIXSOCKDIR=/var/run/bpfcountd
+
+bpfcountd_start() {
+	local instance="$1"
+	local cfg="$2"
+	local disabled
+
+	local ifname
+	local prefilter
+	local filterfile
+
+	echo "bpfcountd_start"
+	config_get_bool disabled "$cfg" disabled 0
+	[ "$disabled" -gt 0 ] && return 0
+
+	mkdir -p "$UNIXSOCKDIR"
+
+	config_get ifname "$cfg" "ifname"
+	config_get prefilter "$cfg" "prefilter"
+	config_get filterfile "$cfg" "filterfile"
+
+	[ -z "$ifname" ] && {
+		echo "Error: no ifname specified for $cfg" >&2
+		return 0
+	}
+	[ -z "$filterfile" ] && {
+		echo "Error: no filterfile specified for $cfg" >&2
+		return 0
+	}
+
+	procd_open_instance "$instance"
+
+	procd_set_param command /usr/sbin/bpfcountd
+	procd_append_param command -i "$ifname"
+	procd_append_param command -f "$filterfile"
+	procd_append_param command -u $UNIXSOCKDIR/"${instance}".sock
+	[ -n "$prefilter" ] && procd_append_param command -F "$prefilter"
+
+	procd_set_param respawn ${respawn_threshold:-3600} ${respawn_timeout:-5} ${respawn_retry:-5}
+
+	procd_set_param stderr 1
+	procd_close_instance
+}
+
+start_service() {
+	local instance="$1"
+	local cfg="$2"
+	local instance_found=0
+
+	. /lib/functions/network.sh
+
+	[ -z "$cfg" ] && cfg="$instance"
+
+	echo "start_service"
+	config_cb() {
+		local type="$1"
+		local name="$2"
+		if [ "$type" = "bpfcountd" ]; then
+			if [ -n "$cfg" -a "$cfg" = "$name" ]; then
+				instance_found=1
+			fi
+		fi
+	}
+
+	config_load bpfcountd
+
+	if [ -n "$instance" ]; then
+		[ "$instance_found" -gt 0 ] || return
+		bpfcountd_start "$instance" "$cfg"
+	else
+		config_foreach bpfcountd_start bpfcountd
+	fi
+}
+
+stop_service() {
+	local cfg="$1"
+
+	if [ -n "$cfg" ]; then
+		rm $UNIXSOCKDIR/$cfg.sock
+	else
+		rm $UNIXSOCKDIR/*.sock
+	fi
+}