MAJOR: namespace: add Linux network namespace support
This patch makes it possible to create binds and servers in separate
namespaces. This can be used to proxy between multiple completely independent
virtual networks (with possibly overlapping IP addresses) and a
non-namespace-aware proxy implementation that supports the proxy protocol (v2).
The setup is something like this:
net1 on VLAN 1 (namespace 1) -\
net2 on VLAN 2 (namespace 2) -- haproxy ==== proxy (namespace 0)
net3 on VLAN 3 (namespace 3) -/
The proxy is configured to make server connections through haproxy and sending
the expected source/target addresses to haproxy using the proxy protocol.
The network namespace setup on the haproxy node is something like this:
= 8< =
$ cat setup.sh
ip netns add 1
ip link add link eth1 type vlan id 1
ip link set eth1.1 netns 1
ip netns exec 1 ip addr add 192.168.91.2/24 dev eth1.1
ip netns exec 1 ip link set eth1.$id up
...
= 8< =
= 8< =
$ cat haproxy.cfg
frontend clients
bind 127.0.0.1:50022 namespace 1 transparent
default_backend scb
backend server
mode tcp
server server1 192.168.122.4:2222 namespace 2 send-proxy-v2
= 8< =
A bind line creates the listener in the specified namespace, and connections
originating from that listener also have their network namespace set to
that of the listener.
A server line either forces the connection to be made in a specified
namespace or may use the namespace from the client-side connection if that
was set.
For more documentation please read the documentation included in the patch
itself.
Signed-off-by: KOVACS Tamas <ktamas@balabit.com>
Signed-off-by: Sarkozi Laszlo <laszlo.sarkozi@balabit.com>
Signed-off-by: KOVACS Krisztian <hidden@balabit.com>
diff --git a/src/namespace.c b/src/namespace.c
new file mode 100644
index 0000000..a22f1a5
--- /dev/null
+++ b/src/namespace.c
@@ -0,0 +1,114 @@
+#define _GNU_SOURCE
+
+#include <common/namespace.h>
+#include <common/compiler.h>
+#include <common/hash.h>
+#include <common/errors.h>
+#include <proto/log.h>
+#include <types/global.h>
+
+#include <sched.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/socket.h>
+
+#include <string.h>
+#ifdef CONFIG_HAP_NS
+
+/* Opens the namespace <ns_name> and returns the FD or -1 in case of error
+ * (check errno).
+ */
+static int open_named_namespace(const char *ns_name)
+{
+ if (chunk_printf(&trash, "/var/run/netns/%s", ns_name) < 0)
+ return -1;
+ return open(trash.str, O_RDONLY);
+}
+
+static int default_namespace = -1;
+
+static int init_default_namespace()
+{
+ if (chunk_printf(&trash, "/proc/%d/ns/net", getpid()) < 0)
+ return -1;
+ default_namespace = open(trash.str, O_RDONLY);
+ return default_namespace;
+}
+
+static struct eb_root namespace_tree_root = EB_ROOT;
+
+int netns_init(void)
+{
+ int err_code = 0;
+
+ /* if no namespaces have been defined in the config then
+ * there is no point in trying to initialize anything:
+ * my_socketat() will never be called with a valid namespace
+ * structure and thus switching back to the default namespace
+ * is not needed either */
+ if (!eb_is_empty(&namespace_tree_root)) {
+ if (init_default_namespace() < 0) {
+ Alert("Failed to open the default namespace.\n");
+ err_code |= ERR_ALERT | ERR_FATAL;
+ }
+ }
+
+ return err_code;
+}
+
+struct netns_entry* netns_store_insert(const char *ns_name)
+{
+ struct netns_entry *entry = NULL;
+ int fd = open_named_namespace(ns_name);
+ if (fd == -1)
+ goto out;
+
+ entry = (struct netns_entry *)calloc(1, sizeof(struct netns_entry));
+ if (!entry)
+ goto out;
+ entry->fd = fd;
+ entry->node.key = strdup(ns_name);
+ entry->name_len = strlen(ns_name);
+ ebis_insert(&namespace_tree_root, &entry->node);
+out:
+ return entry;
+}
+
+const struct netns_entry* netns_store_lookup(const char *ns_name, size_t ns_name_len)
+{
+ struct ebpt_node *node;
+
+ node = ebis_lookup_len(&namespace_tree_root, ns_name, ns_name_len);
+ if (node)
+ return ebpt_entry(node, struct netns_entry, node);
+ else
+ return NULL;
+}
+#endif
+
+/* Opens a socket in the namespace described by <ns> with the parameters <domain>,
+ * <type> and <protocol> and returns the FD or -1 in case of error (check errno).
+ */
+int my_socketat(const struct netns_entry *ns, int domain, int type, int protocol)
+{
+ int sock;
+
+#ifdef CONFIG_HAP_NS
+ if (default_namespace < 0 ||
+ (ns && setns(ns->fd, CLONE_NEWNET) == -1))
+ return -1;
+#endif
+ sock = socket(domain, type, protocol);
+
+#ifdef CONFIG_HAP_NS
+ if (ns && setns(default_namespace, CLONE_NEWNET) == -1) {
+ close(sock);
+ return -1;
+ }
+#endif
+
+ return sock;
+}