package/firewall/files/lib/core_init.sh

   1 # Copyright (C) 2009-2011 OpenWrt.org
   2 # Copyright (C) 2008 John Crispin <blogic@openwrt.org>
   3
   4 FW_INITIALIZED=
   5
   6 FW_ZONES=
   7 FW_ZONES4=
   8 FW_ZONES6=
   9 FW_CONNTRACK_ZONES=
  10 FW_NOTRACK_DISABLED=
  11
  12 FW_DEFAULTS_APPLIED=
  13 FW_ADD_CUSTOM_CHAINS=
  14 FW_ACCEPT_REDIRECTS=
  15 FW_ACCEPT_SRC_ROUTE=
  16
  17 FW_DEFAULT_INPUT_POLICY=REJECT
  18 FW_DEFAULT_OUTPUT_POLICY=REJECT
  19 FW_DEFAULT_FORWARD_POLICY=REJECT
  20
  21 FW_DISABLE_IPV4=0
  22 FW_DISABLE_IPV6=0
  23
  24
  25 fw_load_defaults() {
  26         fw_config_get_section "$1" defaults { \
  27                 string input $FW_DEFAULT_INPUT_POLICY \
  28                 string output $FW_DEFAULT_OUTPUT_POLICY \
  29                 string forward $FW_DEFAULT_FORWARD_POLICY \
  30                 boolean drop_invalid 0 \
  31                 boolean syn_flood 0 \
  32                 boolean synflood_protect 0 \
  33                 string synflood_rate 25 \
  34                 string synflood_burst 50 \
  35                 boolean tcp_syncookies 1 \
  36                 boolean tcp_ecn 0 \
  37                 boolean tcp_westwood 0 \
  38                 boolean tcp_window_scaling 1 \
  39                 boolean accept_redirects 0 \
  40                 boolean accept_source_route 0 \
  41                 boolean custom_chains 1 \
  42                 boolean disable_ipv6 0 \
  43         } || return
  44         [ -n "$FW_DEFAULTS_APPLIED" ] && {
  45                 fw_log error "duplicate defaults section detected, skipping"
  46                 return 1
  47         }
  48         FW_DEFAULTS_APPLIED=1
  49
  50         FW_DEFAULT_INPUT_POLICY=$defaults_input
  51         FW_DEFAULT_OUTPUT_POLICY=$defaults_output
  52         FW_DEFAULT_FORWARD_POLICY=$defaults_forward
  53
  54         FW_ADD_CUSTOM_CHAINS=$defaults_custom_chains
  55
  56         FW_ACCEPT_REDIRECTS=$defaults_accept_redirects
  57         FW_ACCEPT_SRC_ROUTE=$defaults_accept_source_route
  58
  59         FW_DISABLE_IPV6=$defaults_disable_ipv6
  60
  61         fw_callback pre defaults
  62
  63         # Seems like there are only one sysctl for both IP versions.
  64         for s in syncookies ecn westwood window_scaling; do
  65                 eval "sysctl -e -w net.ipv4.tcp_${s}=\$defaults_tcp_${s}" >/dev/null
  66         done
  67         fw_sysctl_interface all
  68
  69         fw add i f INPUT   ACCEPT { -m conntrack --ctstate RELATED,ESTABLISHED }
  70         fw add i f OUTPUT  ACCEPT { -m conntrack --ctstate RELATED,ESTABLISHED }
  71         fw add i f FORWARD ACCEPT { -m conntrack --ctstate RELATED,ESTABLISHED }
  72
  73         [ $defaults_drop_invalid == 1 ] && {
  74                 fw add i f INPUT   DROP { -m conntrack --ctstate INVALID }
  75                 fw add i f OUTPUT  DROP { -m conntrack --ctstate INVALID }
  76                 fw add i f FORWARD DROP { -m conntrack --ctstate INVALID }
  77                 FW_NOTRACK_DISABLED=1
  78         }
  79
  80         fw add i f INPUT  ACCEPT { -i lo }
  81         fw add i f OUTPUT ACCEPT { -o lo }
  82
  83         # Compatibility to old 'syn_flood' parameter
  84         [ $defaults_syn_flood == 1 ] && \
  85                 defaults_synflood_protect=1
  86
  87         [ "${defaults_synflood_rate%/*}" == "$defaults_synflood_rate" ] && \
  88                 defaults_synflood_rate="$defaults_synflood_rate/second"
  89
  90         [ $defaults_synflood_protect == 1 ] && {
  91                 echo "Loading synflood protection"
  92                 fw_callback pre synflood
  93                 fw add i f syn_flood
  94                 fw add i f syn_flood RETURN { \
  95                         -p tcp --syn \
  96                         -m limit --limit "${defaults_synflood_rate}" --limit-burst "${defaults_synflood_burst}" \
  97                 }
  98                 fw add i f syn_flood DROP
  99                 fw add i f INPUT syn_flood { -p tcp --syn }
 100                 fw_callback post synflood
 101         }
 102
 103         [ $defaults_custom_chains == 1 ] && {
 104                 echo "Adding custom chains"
 105                 fw add i f input_rule
 106                 fw add i f output_rule
 107                 fw add i f forwarding_rule
 108                 fw add i n prerouting_rule
 109                 fw add i n postrouting_rule
 110
 111                 fw add i f INPUT       input_rule
 112                 fw add i f OUTPUT      output_rule
 113                 fw add i f FORWARD     forwarding_rule
 114                 fw add i n PREROUTING  prerouting_rule
 115                 fw add i n POSTROUTING postrouting_rule
 116         }
 117
 118         fw add i f input
 119         fw add i f output
 120         fw add i f forward
 121
 122         fw add i f INPUT   input
 123         fw add i f OUTPUT  output
 124         fw add i f FORWARD forward
 125
 126         fw add i f reject
 127         fw add i f reject REJECT { --reject-with tcp-reset -p tcp }
 128         fw add i f reject REJECT { --reject-with port-unreach }
 129
 130         fw_set_filter_policy
 131
 132         fw_callback post defaults
 133 }
 134
 135
 136 fw_config_get_zone() {
 137         [ "${zone_NAME}" != "$1" ] || return
 138         fw_config_get_section "$1" zone { \
 139                 string name "$1" \
 140                 string network "" \
 141                 string input "$FW_DEFAULT_INPUT_POLICY" \
 142                 string output "$FW_DEFAULT_OUTPUT_POLICY" \
 143                 string forward "$FW_DEFAULT_FORWARD_POLICY" \
 144                 boolean masq 0 \
 145                 string masq_src "" \
 146                 string masq_dest "" \
 147                 boolean conntrack 0 \
 148                 boolean mtu_fix 0 \
 149                 boolean custom_chains "$FW_ADD_CUSTOM_CHAINS" \
 150                 boolean log 0 \
 151                 string log_limit 10 \
 152                 string family "" \
 153         } || return
 154         [ -n "$zone_name" ] || zone_name=$zone_NAME
 155         [ -n "$zone_network" ] || zone_network=$zone_name
 156 }
 157
 158 fw_load_zone() {
 159         fw_config_get_zone "$1"
 160
 161         list_contains FW_ZONES $zone_name && {
 162                 fw_log error "zone ${zone_name}: duplicated zone, skipping"
 163                 return 0
 164         }
 165         append FW_ZONES $zone_name
 166
 167         fw_callback pre zone
 168
 169         [ $zone_conntrack = 1 -o $zone_masq = 1 ] && \
 170                 append FW_CONNTRACK_ZONES "$zone_name"
 171
 172         local mode
 173         case "$zone_family" in
 174                 *4)
 175                         mode=4
 176                         append FW_ZONES4 $zone_name
 177                         uci_set_state firewall core ${zone_name}_ipv4 1
 178                 ;;
 179                 *6)
 180                         mode=6
 181                         append FW_ZONES6 $zone_name
 182                         uci_set_state firewall core ${zone_name}_ipv6 1
 183                 ;;
 184                 *)
 185                         mode=i
 186                         append FW_ZONES4 $zone_name
 187                         append FW_ZONES6 $zone_name
 188                         uci_set_state firewall core ${zone_name}_ipv4 1
 189                         uci_set_state firewall core ${zone_name}_ipv6 1
 190                 ;;
 191         esac
 192
 193         local chain=zone_${zone_name}
 194
 195         fw add $mode f ${chain}_ACCEPT
 196         fw add $mode f ${chain}_DROP
 197         fw add $mode f ${chain}_REJECT
 198
 199         # TODO: Rename to ${chain}_input
 200         fw add $mode f ${chain}
 201         fw add $mode f ${chain} ${chain}_${zone_input} $
 202
 203         fw add $mode f ${chain}_forward
 204         fw add $mode f ${chain}_forward ${chain}_${zone_forward} $
 205
 206         # TODO: add ${chain}_output
 207         fw add $mode f output ${chain}_${zone_output} $
 208
 209         # TODO: Rename to ${chain}_MASQUERADE
 210         fw add $mode n ${chain}_nat
 211         fw add $mode n ${chain}_prerouting
 212
 213         fw add $mode r ${chain}_notrack
 214
 215         [ $zone_mtu_fix == 1 ] && {
 216                 fw add $mode m ${chain}_MSSFIX
 217                 fw add $mode m FORWARD ${chain}_MSSFIX ^
 218                 uci_set_state firewall core ${zone_name}_tcpmss 1
 219         }
 220
 221         [ $zone_custom_chains == 1 ] && {
 222                 [ $FW_ADD_CUSTOM_CHAINS == 1 ] || \
 223                         fw_die "zone ${zone_name}: custom_chains globally disabled"
 224
 225                 fw add $mode f input_${zone_name}
 226                 fw add $mode f ${chain} input_${zone_name} ^
 227
 228                 fw add $mode f forwarding_${zone_name}
 229                 fw add $mode f ${chain}_forward forwarding_${zone_name} ^
 230
 231                 fw add $mode n prerouting_${zone_name}
 232                 fw add $mode n ${chain}_prerouting prerouting_${zone_name} ^
 233         }
 234
 235         [ "$zone_log" == 1 ] && {
 236                 [ "${zone_log_limit%/*}" == "$zone_log_limit" ] && \
 237                         zone_log_limit="$zone_log_limit/minute"
 238
 239                 local t
 240                 for t in REJECT DROP; do
 241                         fw add $mode f ${chain}_${t} LOG ^ \
 242                                 { -m limit --limit $zone_log_limit --log-prefix "$t($zone_name): " }
 243                 done
 244
 245                 [ $zone_mtu_fix == 1 ] && \
 246                         fw add $mode m ${chain}_MSSFIX LOG ^ \
 247                                 { -m limit --limit $zone_log_limit --log-prefix "MSSFIX($zone_name): " }
 248         }
 249
 250         # NB: if MASQUERADING for IPv6 becomes available we'll need a family check here
 251         if [ "$zone_masq" == 1 ]; then
 252                 local msrc mdst
 253                 for msrc in ${zone_masq_src:-0.0.0.0/0}; do
 254                         case "$msrc" in
 255                                 *.*) fw_get_negation msrc '-s' "$msrc" ;;
 256                                 *)   fw_get_subnet4 msrc '-s' "$msrc" || break ;;
 257                         esac
 258
 259                         for mdst in ${zone_masq_dest:-0.0.0.0/0}; do
 260                                 case "$mdst" in
 261                                         *.*) fw_get_negation mdst '-d' "$mdst" ;;
 262                                         *)   fw_get_subnet4 mdst '-d' "$mdst" || break ;;
 263                                 esac
 264
 265                                 fw add $mode n ${chain}_nat MASQUERADE $ { $msrc $mdst }
 266                         done
 267                 done
 268         fi
 269
 270         fw_callback post zone
 271 }
 272
 273 fw_load_notrack_zone() {
 274         fw_config_get_zone "$1"
 275         list_contains FW_CONNTRACK_ZONES "${zone_name}" && return
 276
 277         fw_callback pre notrack
 278
 279         fw add i r zone_${zone_name}_notrack NOTRACK $
 280
 281         fw_callback post notrack
 282 }
 283
 284
 285 fw_load_include() {
 286         local name="$1"
 287
 288         local path
 289         config_get path ${name} path
 290
 291         [ -e $path ] && ( . $path )
 292 }
 293
 294
 295 fw_clear() {
 296         local policy=$1
 297
 298         fw_set_filter_policy $policy
 299
 300         local tab
 301         for tab in f n r; do
 302                 fw del i $tab
 303         done
 304 }
 305
 306 fw_set_filter_policy() {
 307         local policy=$1
 308
 309         local chn tgt
 310         for chn in INPUT OUTPUT FORWARD; do
 311                 eval "tgt=\${policy:-\${FW_DEFAULT_${chn}_POLICY}}"
 312                 [ $tgt == "REJECT" ] && tgt=reject
 313                 [ $tgt == "ACCEPT" -o $tgt == "DROP" ] || {
 314                         fw add i f $chn $tgt $
 315                         tgt=DROP
 316                 }
 317                 fw policy i f $chn $tgt
 318         done
 319 }
 320
 321
 322 fw_callback() {
 323         local pp=$1
 324         local hk=$2
 325
 326         local libs lib
 327         eval "libs=\$FW_CB_${pp}_${hk}"
 328         [ -n "$libs" ] || return
 329         for lib in $libs; do
 330                 ${lib}_${pp}_${hk}_cb
 331         done
 332 }