radius_udp: Allow source IP address override, maybe...

diff --git a/src/listen/radius/proto_radius_udp.c b/src/listen/radius/proto_radius_udp.c
index 803678a8c31119b682ca839522efc97ceb658bb3..19b4ee2294827857a1832e48b9ca88fbb9a60931 100644 (file)
--- a/src/listen/radius/proto_radius_udp.c
+++ b/src/listen/radius/proto_radius_udp.c
@@ -49,6 +49,10 @@ typedef struct {
        CONF_SECTION                    *cs;                    //!< our configuration
 
        fr_ipaddr_t                     ipaddr;                 //!< IP address to listen on.
+       fr_ipaddr_t                     src_ipaddr;             //!< IP to use for responses, which may be
+                                                               ///< different from the ipaddr we're listening on
+                                                               ///< with L3 load balancing setups.
+       bool                            src_ipaddr_is_set;      //!< Use specified a source ip address.
 
        char const                      *interface;             //!< Interface to bind to.
        char const                      *port_name;             //!< Name of the port for getservent().
@@ -87,6 +91,8 @@ static const CONF_PARSER udp_listen_config[] = {
        { FR_CONF_OFFSET("ipv4addr", FR_TYPE_IPV4_ADDR, proto_radius_udp_t, ipaddr) },
        { FR_CONF_OFFSET("ipv6addr", FR_TYPE_IPV6_ADDR, proto_radius_udp_t, ipaddr) },
 
+       { FR_CONF_OFFSET_IS_SET("src_ipaddr", FR_TYPE_COMBO_IP_ADDR, proto_radius_udp_t, src_ipaddr) },
+
        { FR_CONF_OFFSET("interface", FR_TYPE_STRING, proto_radius_udp_t, interface) },
        { FR_CONF_OFFSET("port_name", FR_TYPE_STRING, proto_radius_udp_t, port_name) },
 
@@ -193,6 +199,7 @@ static ssize_t mod_read(fr_listen_t *li, void **packet_ctx, fr_time_t *recv_time
 static ssize_t mod_write(fr_listen_t *li, void *packet_ctx, UNUSED fr_time_t request_time,
                         uint8_t *buffer, size_t buffer_len, UNUSED size_t written)
 {
+       proto_radius_udp_t const        *inst = talloc_get_type_abort_const(li->app_io_instance, proto_radius_udp_t);
        proto_radius_udp_thread_t       *thread = talloc_get_type_abort(li->thread_instance, proto_radius_udp_thread_t);
 
        fr_io_track_t                   *track = talloc_get_type_abort(packet_ctx, fr_io_track_t);
@@ -216,6 +223,12 @@ static ssize_t mod_write(fr_listen_t *li, void *packet_ctx, UNUSED fr_time_t req
         */
        fr_socket_addr_swap(&socket, &track->address->socket);
 
+       /*
+        *      Override the source ip address in the outbound
+        *      packet.
+        */
+       if (inst->src_ipaddr_is_set) socket.inet.src_ipaddr = inst->src_ipaddr;
+
        /*
         *      This handles the race condition where we get a DUP,
         *      but the original packet replies before we're run.