1 files changed, 132 insertions, 0 deletions
diff --git a/src/namespace.c b/src/namespace.c
new file mode 100644
index 0000000..9cc85a3
--- /dev/null
+++ b/src/namespace.c
@@ -0,0 +1,132 @@
+#define _GNU_SOURCE
+
+#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>
+
+#include <haproxy/api.h>
+#include <haproxy/chunk.h>
+#include <haproxy/errors.h>
+#include <haproxy/global.h>
+#include <haproxy/hash.h>
+#include <haproxy/namespace.h>
+#include <haproxy/signal.h>
+
+/* 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.area, O_RDONLY | O_CLOEXEC);
+}
+
+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.area, O_RDONLY | O_CLOEXEC);
+	return default_namespace;
+}
+
+static struct eb_root namespace_tree_root = EB_ROOT;
+
+static void netns_sig_stop(struct sig_handler *sh)
+{
+	struct ebpt_node *node, *next;
+	struct netns_entry *entry;
+
+	/* close namespace file descriptors and remove registered namespaces from the
+	 * tree when stopping */
+	node = ebpt_first(&namespace_tree_root);
+	while (node) {
+		next = ebpt_next(node);
+		ebpt_delete(node);
+		entry = container_of(node, struct netns_entry, node);
+		free(entry->node.key);
+		close(entry->fd);
+		free(entry);
+		node = next;
+	}
+}
+
+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) {
+			ha_alert("Failed to open the default namespace.\n");
+			err_code |= ERR_ALERT | ERR_FATAL;
+		}
+	}
+
+	signal_register_fct(0, netns_sig_stop, 0);
+
+	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 = calloc(1, sizeof(*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;
+}
+
+/* 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;
+
+	if (default_namespace >= 0 && ns && setns(ns->fd, CLONE_NEWNET) == -1)
+		return -1;
+
+	sock = socket(domain, type, protocol);
+
+	if (default_namespace >= 0 && ns && setns(default_namespace, CLONE_NEWNET) == -1) {
+		if (sock >= 0)
+			close(sock);
+		return -1;
+	}
+	return sock;
+}
+
+REGISTER_BUILD_OPTS("Built with network namespace support.");