Reimplementation of 6a3e1d98 commit

With the 6a3e1d98 commit NetworkManager was throwing an assertion so
we take a different approach when we create the bridge interface.
Also if the <interface-with-internet> is already a bridge interface
we skip creation.

The new approach is:

   1) Save the IPs and route table of INTERNET_IFACE
   2) If NetworkManager is running set INTERNET_IFACE as unmanaged
   3) Create BRIDGE_IFACE and add INTERNET_IFACE to it
   4) Set the previously saved IPs and route table to BRIDGE_IFACE

Better fix #19

README.md

@@ -54,6 +54,9 @@
 ### Bridged Internet sharing:
     create_ap -m bridge wlan0 eth0 MyAccessPoint MyPassPhrase
 
+### Bridged Internet sharing (pre-configured bridge interface):
+    create_ap -m bridge wlan0 br0 MyAccessPoint MyPassPhrase
+
 ### Internet sharing from the same WiFi interface:
     create_ap wlan0 wlan0 MyAccessPoint MyPassPhrase
 

create_ap

@@ -43,6 +43,8 @@ usage() {
     echo "  * If you're not using the --no-virt option, then you can create an AP with the same"
     echo "    interface you are getting your Internet connection."
     echo "  * You can pass your SSID and password through pipe or through arguments (see examples)."
+    echo "  * On bridge method if the <interface-with-internet> is not a bridge interface, then"
+    echo "    a bridge interface is created automatically."
     echo
     echo "Examples:"
     echo "  $(basename $0) wlan0 eth0 MyAccessPoint MyPassPhrase"
@@ -52,6 +54,7 @@ usage() {
     echo "  $(basename $0) wlan0 wlan0 MyAccessPoint MyPassPhrase"
     echo "  $(basename $0) -n wlan0 MyAccessPoint MyPassPhrase"
     echo "  $(basename $0) -m bridge wlan0 eth0 MyAccessPoint MyPassPhrase"
+    echo "  $(basename $0) -m bridge wlan0 br0 MyAccessPoint MyPassPhrase"
     echo "  $(basename $0) --driver rtl871xdrv wlan0 eth0 MyAccessPoint MyPassPhrase"
 }
 
@@ -88,6 +91,10 @@ is_wifi_interface() {
     return 1
 }
 
+is_bridge_interface() {
+    brctl show | cut -f1 | grep -E "^$1\$" > /dev/null 2>&1
+}
+
 get_phy_device() {
     for x in /sys/class/ieee80211/*; do
         [[ ! -d "$x" ]] && continue
@@ -160,9 +167,8 @@ get_macaddr() {
 
 get_avail_bridge() {
     for i in {0..100}; do
-        curr_bridge=$(brctl show | grep "br$i" | cut -s -f1)
+        if ! is_bridge_interface "br${i}"; then
-        if [[ -z $curr_bridge ]]; then
+            echo "br${i}"
-            echo "br$i"
             return
         fi
     done
@@ -177,7 +183,6 @@ get_new_macaddr() {
     echo $NEWMAC
 }
 
-ADDED_UNMANAGED=0
 NETWORKMANAGER_CONF=/etc/NetworkManager/NetworkManager.conf
 NM_OLDER_VERSION=1
 
@@ -323,6 +328,8 @@ BRIDGE_IFACE=
 OLD_IP_FORWARD=
 OLD_BRIDGE_IPTABLES=
 OLD_MACADDR=
+IP_ADDRS=
+ROUTE_ADDRS=
 
 cleanup() {
     trap "" SIGINT
@@ -345,19 +352,39 @@ cleanup() {
             iptables -D FORWARD -i ${INTERNET_IFACE} -d ${GATEWAY%.*}.0/24 -j ACCEPT > /dev/null 2>&1
             [[ -n $OLD_IP_FORWARD ]] && echo $OLD_IP_FORWARD > /proc/sys/net/ipv4/ip_forward
         elif [[ "$SHARE_METHOD" == "bridge" ]]; then
-            ip route show dev $BRIDGE_IFACE | grep -v -E '^default' | while read x; do
+            if [[ -n $OLD_BRIDGE_IPTABLES ]]; then
-                ip route del $x dev $BRIDGE_IFACE
+                echo $OLD_BRIDGE_IPTABLES > /proc/sys/net/bridge/bridge-nf-call-iptables
-                ip route add $x dev $INTERNET_IFACE
+            fi
-            done
 
-            ip route show dev $BRIDGE_IFACE | grep -E '^default' | while read x; do
+            if ! is_bridge_interface $INTERNET_IFACE; then
-                ip route del $x dev $BRIDGE_IFACE
+                ip link set down $BRIDGE_IFACE
-                ip route add $x dev $INTERNET_IFACE
+                brctl delbr $BRIDGE_IFACE
-            done
+                ip addr flush $INTERNET_IFACE
+                ip link set dev $INTERNET_IFACE up
 
-            ip link set down $BRIDGE_IFACE
+                for x in "${IP_ADDRS[@]}"; do
-            brctl delbr $BRIDGE_IFACE
+                    x="${x/inet/}"
-            [[ -n $OLD_BRIDGE_IPTABLES ]] && echo $OLD_BRIDGE_IPTABLES > /proc/sys/net/bridge/bridge-nf-call-iptables
+                    x="${x/secondary/}"
+                    x="${x/dynamic/}"
+                    x=$(echo $x | sed 's/\([0-9]\)sec/\1/g')
+                    x="${x/${INTERNET_IFACE}/}"
+                    ip addr add $x dev $INTERNET_IFACE
+                done
+
+                ip route flush dev $INTERNET_IFACE
+
+                for x in "${ROUTE_ADDRS[@]}"; do
+                    [[ "$x" == default* ]] && continue
+                    ip route add $x dev $INTERNET_IFACE
+                done
+
+                for x in "${ROUTE_ADDRS[@]}"; do
+                    [[ "$x" != default* ]] && continue
+                    ip route add $x dev $INTERNET_IFACE
+                done
+
+                networkmanager_rm_unmanaged_if_needed $INTERNET_IFACE
+            fi
         fi
     fi
 
@@ -501,17 +528,6 @@ if [[ "$SHARE_METHOD" != "nat" && "$SHARE_METHOD" != "bridge" && "$SHARE_METHOD"
     exit 1
 fi
 
-if [[ "$SHARE_METHOD" == "bridge" ]]; then
-    OLD_BRIDGE_IPTABLES=$(cat /proc/sys/net/bridge/bridge-nf-call-iptables)
-    BRIDGE_IFACE=$(get_avail_bridge)
-    if [[ -z $BRIDGE_IFACE ]]; then
-        echo "ERROR: No availabe bridges < br100" >&2
-        exit 1
-    fi
-elif [[ "$SHARE_METHOD" == "nat" ]]; then
-    OLD_IP_FORWARD=$(cat /proc/sys/net/ipv4/ip_forward)
-fi
-
 if [[ "$SHARE_METHOD" != "none" ]]; then
     MIN_REQUIRED_ARGS=2
 else
@@ -562,6 +578,23 @@ else
     fi
 fi
 
+if [[ "$SHARE_METHOD" == "bridge" ]]; then
+    OLD_BRIDGE_IPTABLES=$(cat /proc/sys/net/bridge/bridge-nf-call-iptables)
+
+    if is_bridge_interface $INTERNET_IFACE; then
+        BRIDGE_IFACE=$INTERNET_IFACE
+    else
+        BRIDGE_IFACE=$(get_avail_bridge)
+    fi
+
+    if [[ -z $BRIDGE_IFACE ]]; then
+        echo "ERROR: No availabe bridges < br100" >&2
+        exit 1
+    fi
+elif [[ "$SHARE_METHOD" == "nat" ]]; then
+    OLD_IP_FORWARD=$(cat /proc/sys/net/ipv4/ip_forward)
+fi
+
 if [[ $NO_VIRT -eq 1 && "$WIFI_IFACE" == "$INTERNET_IFACE" ]]; then
     echo -n "ERROR: You can not share your connection from the same" >&2
     echo " interface if you are using --no-virt option." >&2
@@ -693,48 +726,65 @@ if [[ "$SHARE_METHOD" != "none" ]]; then
     elif [[ "$SHARE_METHOD" == "bridge" ]]; then
         # disable iptables rules for bridged interfaces
         echo 0 > /proc/sys/net/bridge/bridge-nf-call-iptables || die
-        # create and initialize bridged interface
-        brctl addbr ${BRIDGE_IFACE} || die
-        brctl addif ${BRIDGE_IFACE} ${INTERNET_IFACE} || die
 
         # to initialize the bridge interface correctly we need to do the following:
         #
-        # 1) duplicate the IPs of INTERNET_IFACE to BRIDGE_IFACE
+        # 1) save the IPs and route table of INTERNET_IFACE
-        # 2) duplicate routing table of INTERNET_IFACE to BRIDGE_IFACE
+        # 2) if NetworkManager is running set INTERNET_IFACE as unmanaged
-        # 3) delete routing table of INTERNET_IFACE
+        # 3) create BRIDGE_IFACE and add INTERNET_IFACE to it
-        # NOTE: we don't need to delete the IPs of INTERNET_IFACE
+        # 4) set the previously saved IPs and route table to BRIDGE_IFACE
         #
         # we need the above because BRIDGE_IFACE is the master interface from now on
         # and it must know where is connected, otherwise connection is lost.
-        ip link set dev ${BRIDGE_IFACE} up || die
+        if ! is_bridge_interface $INTERNET_IFACE; then
+            echo -n "Create a bridge interface... "
+            OLD_IFS="$IFS"
+            IFS=$'\n'
 
-        ip addr show $INTERNET_IFACE | grep -E '[[:blank:]]+inet ' | while read x; do
+            IP_ADDRS=( $(ip addr show $INTERNET_IFACE | grep -A 1 -E 'inet[[:blank:]]' | paste - -) )
-            IPADDR=$(echo $x | sed 's/inet \([^ ]*\).*/\1/')
+            ROUTE_ADDRS=( $(ip route show dev $INTERNET_IFACE) )
-            BRDADDR=
+
-            if [[ $x == *\ brd\ * ]]; then
+            IFS="$OLD_IFS"
-                BRDADDR=$(echo $x | sed 's/.* brd \([^ ]*\).*/\1/')
+
+            if networkmanager_is_running; then
+                networkmanager_add_unmanaged $INTERNET_IFACE
+                networkmanager_wait_until_unmanaged $INTERNET_IFACE
             fi
-            if [[ -n "$BRDADDR" ]]; then
-                ip addr add $IPADDR broadcast $BRDADDR dev $BRIDGE_IFACE || die
-            else
-                ip addr add $IPADDR dev $BRIDGE_IFACE || die
-            fi
-        done
 
-        # remove any existing entries that were added from 'ip addr add'
+            brctl addbr $BRIDGE_IFACE || die
-        ip route flush dev $BRIDGE_IFACE || die
+            brctl setfd $BRIDGE_IFACE 0
+            brctl addif $BRIDGE_IFACE $INTERNET_IFACE || die
+            ip link set dev $BRIDGE_IFACE up || die
+            ip link set dev $INTERNET_IFACE up || die
 
-        # we must first add the entries that specify the subnets and then the
+            ip addr flush $INTERNET_IFACE
-        # gateway entry, otherwise 'ip addr add' will return an error
+            for x in "${IP_ADDRS[@]}"; do
-        ip route show dev $INTERNET_IFACE | grep -v -E '^default' | while read x; do
+                x="${x/inet/}"
-            ip route del $x dev $INTERNET_IFACE || die
+                x="${x/secondary/}"
-            ip route add $x dev $BRIDGE_IFACE || die
+                x="${x/dynamic/}"
-        done
+                x=$(echo $x | sed 's/\([0-9]\)sec/\1/g')
+                x="${x/${INTERNET_IFACE}/}"
+                ip addr add $x dev $BRIDGE_IFACE || die
+            done
 
-        ip route show dev $INTERNET_IFACE | grep -E '^default' | while read x; do
+            # remove any existing entries that were added from 'ip addr add'
-            ip route del $x dev $INTERNET_IFACE || die
+            ip route flush dev $INTERNET_IFACE
-            ip route add $x dev $BRIDGE_IFACE || die
+            ip route flush dev $BRIDGE_IFACE
-        done
+
+            # we must first add the entries that specify the subnets and then the
+            # gateway entry, otherwise 'ip addr add' will return an error
+            for x in "${ROUTE_ADDRS[@]}"; do
+                [[ "$x" == default* ]] && continue
+                ip route add $x dev $BRIDGE_IFACE || die
+            done
+
+            for x in "${ROUTE_ADDRS[@]}"; do
+                [[ "$x" != default* ]] && continue
+                ip route add $x dev $BRIDGE_IFACE || die
+            done
+
+            echo "$BRIDGE_IFACE created."
+        fi
     fi
 else
     echo "No Internet sharing"