kernel-netlink: Allow change of Netlink socket receive buffer size

Signed-off-by: Thomas Egerer <thomas.egerer@secunet.com>

diff --git a/conf/plugins/kernel-netlink.opt b/conf/plugins/kernel-netlink.opt
index 77ba6ea9798c71e9752cec4117706fb4465fc200..1136af1be6f9b171d451e685992fc5817f12ae81 100644 (file)
--- a/conf/plugins/kernel-netlink.opt
+++ b/conf/plugins/kernel-netlink.opt
@@ -1,6 +1,14 @@
 charon.plugins.kernel-netlink.buflen = <min(PAGE_SIZE, 8192)>
        Buffer size for received Netlink messages.
 
+charon.plugins.kernel-netlink.force_receive_buffer_size = no
+       Force maximum Netlink receive buffer on Netlink socket.
+
+       If the maximum Netlink socket receive buffer in bytes set by
+       _receive_buffer_size_ exceeds the system-wide maximum from
+       /proc/sys/net/core/rmem_max, this option can be used to override the limit.
+       Enabling this option requires special priviliges (CAP_NET_ADMIN).
+
 charon.plugins.kernel-netlink.fwmark =
        Firewall mark to set on the routing rule that directs traffic to our routing
        table.
@@ -39,6 +47,15 @@ charon.plugins.kernel-netlink.port_bypass = no
        port based policies use global XFRM bypass policies for the used IKE UDP
        ports.
 
+charon.plugins.kernel-netlink.receive_buffer_size = 0
+       Maximum Netlink socket receive buffer in bytes.
+
+       Maximum Netlink socket receive buffer in bytes. This value controls how many
+       bytes of Netlink messages can be received on a Netlink socket. The default
+       value is set by /proc/sys/net/core/rmem_default. The specified value cannot
+       exceed the system-wide maximum from /proc/sys/net/core/rmem_max, unless
+       _force_receive_buffer_size_     is enabled.
+
 charon.plugins.kernel-netlink.roam_events = yes
        Whether to trigger roam events when interfaces, addresses or routes change.
 

diff --git a/src/libcharon/plugins/kernel_netlink/kernel_netlink_shared.c b/src/libcharon/plugins/kernel_netlink/kernel_netlink_shared.c
index 7165b655b6169bcd9d4c8a7a7148fe227d0777ce..44609002fd08d784deea28f6b54fbb1588d9d568 100644 (file)
--- a/src/libcharon/plugins/kernel_netlink/kernel_netlink_shared.c
+++ b/src/libcharon/plugins/kernel_netlink/kernel_netlink_shared.c
@@ -15,6 +15,29 @@
  * for more details.
  */
 
+/*
+ * Copyright (C) 2016 secunet Security Networks AG
+ * Copyright (C) 2016 Thomas Egerer
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
 #include <sys/socket.h>
 #include <linux/netlink.h>
 #include <linux/rtnetlink.h>
@@ -557,6 +580,8 @@ netlink_socket_t *netlink_socket_create(int protocol, enum_name_t *names,
        struct sockaddr_nl addr = {
                .nl_family = AF_NETLINK,
        };
+       bool force_buf = FALSE;
+       int rcvbuf_size = 0;
 
        INIT(this,
                .public = {
@@ -606,6 +631,25 @@ netlink_socket_t *netlink_socket_create(int protocol, enum_name_t *names,
                destroy(this);
                return NULL;
        }
+       rcvbuf_size = lib->settings->get_int(lib->settings,
+                                               "%s.plugins.kernel-netlink.receive_buffer_size",
+                                               rcvbuf_size, lib->ns);
+       if (rcvbuf_size)
+       {
+               int optname;
+
+               force_buf = lib->settings->get_bool(lib->settings,
+                                               "%s.plugins.kernel-netlink.force_receive_buffer_size",
+                                               force_buf, lib->ns);
+               optname = force_buf ? SO_RCVBUFFORCE : SO_RCVBUF;
+
+               if (setsockopt(this->socket, SOL_SOCKET, optname, &rcvbuf_size,
+                                          sizeof(rcvbuf_size)) == -1)
+               {
+                       DBG1(DBG_KNL, "failed to %supdate receive buffer size to %d: %s",
+                                       force_buf ? "forcibly " : "", rcvbuf_size, strerror(errno));
+               }
+       }
        if (this->parallel)
        {
                lib->watcher->add(lib->watcher, this->socket, WATCHER_READ, watch, this);