#!/bin/sh
#------------------------------------------------------------------------------
# /usr/share/radvd.api - public API for configuring radvd
#
# Last Update: $Id$
#------------------------------------------------------------------------------

if [ -z "$radvd_api" ]
then
radvd_api=yes

. /etc/boot.d/lazy.inc
. /etc/boot.d/list.inc
. /etc/boot.d/locking.inc
. /usr/share/circuits/api

# contains the radvd configuration
radvd_conf_file=/etc/radvd.conf
# contains circuit-specific configuration parts
radvd_conf_dir=/var/run/radvd
# contains the radvd PID file
radvd_pid_file=/var/run/radvd.pid

# Removes the radvd configuration for a given circuit.
# Input:
#   $1 = associated circuit
radvd_remove_configuration()
{
    lazy_execute_early --idempotent radvd_do_remove_configuration "$@"
    lazy_execute_late --idempotent radvd_reload
}

# Removes the radvd configuration for a given circuit (implementation).
# Input:
#   $1 = associated circuit
radvd_do_remove_configuration()
{
    local id=$1

    sync_lock_resource "radvd-$id" radvd_remove_configuration
    rm -f "$radvd_conf_dir/$id.conf"
    sync_unlock_resource "radvd-$id" radvd_remove_configuration
}

# Requests advertisement of a prefix.
# Input:
#   $1 = associated circuit
#   $2 = prefix with netmask length
#   $3 = valid lifetime of prefix in seconds, or "forever"
#   $4 = preferred lifetime of prefix in seconds, or "forever"
#   $5 = "yes" if prefix is on-link, "no" if link state is unknown
#   $6 = "yes" if lifetimes should be decremented, "no" if the lifetimes
#        should not change across the router advertisements
#        (evaluated only if both lifetimes are neither "forever" nor zero)
radvd_advertise_prefix()
{
    lazy_execute --idempotent radvd_do_advertise_prefix "$@"
    lazy_execute_late --idempotent radvd_reload
}

# Requests advertisement of a prefix (implementation).
# Input:
#   $1 = associated circuit
#   $2 = prefix with netmask length
#   $3 = valid lifetime of prefix in seconds, or "forever"
#   $4 = preferred lifetime of prefix in seconds, or "forever"
#   $5 = "yes" if prefix is on-link, "no" if link state is unknown
#   $6 = "yes" if lifetimes should be decremented, "no" if the lifetimes
#        should not change across the router advertisements
#        (evaluated only if both lifetimes are neither "forever" nor zero)
radvd_do_advertise_prefix()
{
    local id=$1 prefix=$2 validlft=$3 preflft=$4 onlink=$5 aging=$6

    # use radvd's terminology
    [ $validlft = "forever" ] && validlft=infinity
    [ $preflft = "forever" ] && preflft=infinity

    mkdir -p "$radvd_conf_dir"
    sync_lock_resource "radvd-$id" radvd_advertise_prefix
    {
        echo "    prefix $prefix {"
        echo "      AdvAutonomous on;"
        echo "      AdvValidLifetime $validlft;"
        echo "      AdvPreferredLifetime $preflft;"

        if [ "$aging" = "yes" \
                -a $validlft != "infinity" -a $validlft != 0 \
                -a $preflft != "infinity" -a $preflft != 0 ]
        then
            echo "      DecrementLifetimes on;"
        fi

        if [ "$onlink" = "yes" ]
        then
            echo "      AdvOnLink on;"
        else
            echo "      AdvOnLink off;"
        fi

        echo "    };"
    } >> "$radvd_conf_dir/$id.conf"
    sync_unlock_resource "radvd-$id" radvd_advertise_prefix
}

# Requests advertisement of a DNS server.
# Input:
#   $1 = associated circuit
#   $2 = address of DNS server
#   $3 = lifetime of address in seconds, or "forever"; if not set,
#        a default lifetime (twice the maximum time between two router
#        advertisements) is used
radvd_advertise_dns()
{
    lazy_execute --idempotent radvd_do_advertise_dns "$@"
    lazy_execute_late --idempotent radvd_reload
}

# Requests advertisement of a DNS server (implementation).
# Input:
#   $1 = associated circuit
#   $2 = address of DNS server
#   $3 = lifetime of address in seconds, or "forever"; if not set,
#        a default lifetime (twice the maximum time between two router
#        advertisements) is used
radvd_do_advertise_dns()
{
    local id=$1 addr=$2 lifetime=$3

    # use radvd's terminology
    [ $lifetime = "forever" ] && lifetime=infinity

    mkdir -p "$radvd_conf_dir"
    sync_lock_resource "radvd-$id" radvd_advertise_dns
    {
        echo "    RDNSS $addr {"

        # if lifetime is not set, use radvd's default (2*MaxRtrAdvInterval)
        if [ -n "$lifetime" ]
        then
            echo "      AdvRDNSSLifetime $lifetime;"
        fi

        echo "    };"
    } >> "$radvd_conf_dir/$id.conf"
    sync_unlock_resource "radvd-$id" radvd_advertise_dns
}

# Generates the configuration for radvd and reloads the daemon.
# Combines all temporary configuration bits created by radvd_advertise_prefix().
radvd_reload()
{
    sync_lock_resource "radvd_db" radvd_reload

    local devs conf transformed_dev
    for conf in "$radvd_conf_dir"/*.conf
    do
        [ -f "$conf" ] || continue
        local circ_id=$(basename "$conf" .conf) circ_dev
        circuit_read_field $circ_id circ_dev
        circ_dev=$(circuit_get_interface $circ_dev)
        if [ -n "$circ_dev" ]
        then
            transformed_dev=$(to_shell_id "$circ_dev")
            if ! list_is_in $transformed_dev $devs
            then
                devs="$devs $transformed_dev"
                eval local dev_${transformed_dev}="\"\$circ_dev\""
                eval local circuits_${transformed_dev}=
            fi

            eval local circuits_${transformed_dev}="\"\$circuits_${transformed_dev} \$circ_id\""
        fi
    done

    for transformed_dev in $devs
    do
        eval local dev=\$dev_${transformed_dev}
        echo "interface $dev {"
        echo "    IgnoreIfMissing on;"
        echo "    AdvSendAdvert on;"

        eval local circ_ids=\$circuits_${transformed_dev} circ_id
        for circ_id in $circ_ids
        do
            local input="$radvd_conf_dir/$circ_id.conf"
            [ -f $input ] || continue
            cat $input
        done

        echo "};"
    done > "$radvd_conf_file"

    if [ -s "$radvd_conf_file" ]
    then
        if [ -s "$radvd_pid_file" ]
        then
            local pid
            read pid < "$radvd_pid_file"
            kill -HUP $pid
        else
            radvd -C "$radvd_conf_file" -p "$radvd_pid_file" -m syslog >/dev/null 2>&1 &
        fi
    else
        if [ -s "$radvd_pid_file" ]
        then
            local pid
            read pid < "$radvd_pid_file"
            kill $pid
        fi
    fi

    sync_unlock_resource "radvd_db" radvd_reload
}

fi # radvd_api