[CRIU] [PATCH 07/10] net: set a proper network namespace to create a socket

[Andrei Vagin]

From: Andrei Vagin <avagin at virtuozzo.com>

Each socket has to be restored from a proper network namespaces
where it was created.

We set a specified network namespace before restoring a socket.
A task network namespace is set after restoring all files.

v2: don't set the root netns for transport sockets

Signed-off-by: Andrei Vagin <avagin at virtuozzo.com>
---
 criu/include/sockets.h |  2 ++
 criu/sk-inet.c         |  3 +++
 criu/sk-netlink.c      |  3 +++
 criu/sk-packet.c       |  3 +++
 criu/sk-unix.c         |  7 ++++++-
 criu/sockets.c         | 37 +++++++++++++++++++++++++++++++++++++
 6 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/criu/include/sockets.h b/criu/include/sockets.h
index 7685eeb..28bf91e 100644
--- a/criu/include/sockets.h
+++ b/criu/include/sockets.h
@@ -82,4 +82,6 @@ static inline int sk_decode_shutdown(int val)
 #define NETLINK_SOCK_DIAG NETLINK_INET_DIAG
 #endif
 
+extern int set_netns(uint32_t ns_id);
+
 #endif /* __CR_SOCKETS_H__ */
diff --git a/criu/sk-inet.c b/criu/sk-inet.c
index bb898d5..ee6ce60 100644
--- a/criu/sk-inet.c
+++ b/criu/sk-inet.c
@@ -643,6 +643,9 @@ static int open_inet_sk(struct file_desc *d, int *new_fd)
 	if (inet_validate_address(ie))
 		return -1;
 
+	if (set_netns(ie->ns_id))
+		return -1;
+
 	sk = socket(ie->family, ie->type, ie->proto);
 	if (sk < 0) {
 		pr_perror("Can't create inet socket");
diff --git a/criu/sk-netlink.c b/criu/sk-netlink.c
index 4ef934a..1101ee8 100644
--- a/criu/sk-netlink.c
+++ b/criu/sk-netlink.c
@@ -179,6 +179,9 @@ static int open_netlink_sk(struct file_desc *d, int *new_fd)
 
 	pr_info("Opening netlink socket id %#x\n", nse->id);
 
+	if (set_netns(nse->ns_id))
+		return -1;
+
 	sk = socket(PF_NETLINK, SOCK_RAW, nse->protocol);
 	if (sk < 0) {
 		pr_perror("Can't create netlink sock");
diff --git a/criu/sk-packet.c b/criu/sk-packet.c
index f1cf117..297877a 100644
--- a/criu/sk-packet.c
+++ b/criu/sk-packet.c
@@ -470,6 +470,9 @@ static int open_packet_sk(struct file_desc *d, int *new_fd)
 
 	pr_info("Opening packet socket id %#x\n", pse->id);
 
+	if (set_netns(pse->ns_id))
+		return -1;
+
 	if (pse->type == SOCK_PACKET)
 		return open_packet_sk_spkt(pse, new_fd);
 
diff --git a/criu/sk-unix.c b/criu/sk-unix.c
index 4d7a890..bf1a3b8 100644
--- a/criu/sk-unix.c
+++ b/criu/sk-unix.c
@@ -1095,6 +1095,9 @@ static int open_unixsk_pair_master(struct unix_sk_info *ui, int *new_fd)
 	pr_info("Opening pair master (id %#x ino %#x peer %#x)\n",
 			ui->ue->id, ui->ue->ino, ui->ue->peer);
 
+	if (set_netns(ui->ue->ns_id))
+		return -1;
+
 	if (socketpair(PF_UNIX, ui->ue->type, 0, sk) < 0) {
 		pr_perror("Can't make socketpair");
 		return -1;
@@ -1170,6 +1173,9 @@ static int open_unixsk_standalone(struct unix_sk_info *ui, int *new_fd)
 	pr_info("Opening standalone socket (id %#x ino %#x peer %#x)\n",
 			ui->ue->id, ui->ue->ino, ui->ue->peer);
 
+	if (set_netns(ui->ue->ns_id))
+		return -1;
+
 	/*
 	 * Check if this socket was connected to criu service.
 	 * If so, put response, that dumping and restoring
@@ -1273,7 +1279,6 @@ static int open_unixsk_standalone(struct unix_sk_info *ui, int *new_fd)
 			return -1;
 		}
 
-
 		sk = socket(PF_UNIX, ui->ue->type, 0);
 		if (sk < 0) {
 			pr_perror("Can't make unix socket");
diff --git a/criu/sockets.c b/criu/sockets.c
index 86a6b21..95da999 100644
--- a/criu/sockets.c
+++ b/criu/sockets.c
@@ -1,3 +1,4 @@
+#include <sched.h>
 #include <unistd.h>
 #include <sys/socket.h>
 #include <linux/netlink.h>
@@ -24,6 +25,8 @@
 #include "net.h"
 #include "xmalloc.h"
 #include "fs-magic.h"
+#include "pstree.h"
+#include "util.h"
 
 #ifndef SOCK_DIAG_BY_FAMILY
 #define SOCK_DIAG_BY_FAMILY 20
@@ -740,3 +743,37 @@ int collect_sockets(struct ns_id *ns)
 
 	return err;
 }
+
+static uint32_t last_ns_id = 0;
+
+int set_netns(uint32_t ns_id)
+{
+	struct ns_id *ns;
+	int nsfd;
+
+	if (!(root_ns_mask & CLONE_NEWNET))
+		return 0;
+
+	if (ns_id == last_ns_id)
+		return 0;
+
+	ns = lookup_ns_by_id(ns_id, &net_ns_desc);
+	if (ns == NULL) {
+		pr_err("Unable to find a network namespace");
+		return -1;
+	}
+	nsfd = open_proc(root_item->pid->ns[0].virt, "fd/%d", ns->net.ns_fd);
+	if (nsfd < 0)
+		return -1;
+	if (setns(nsfd, CLONE_NEWNET)) {
+		pr_perror("Unable to switch a network namespace");
+		close(nsfd);
+		return -1;
+	}
+	last_ns_id = ns_id;
+	close(nsfd);
+
+	close_pid_proc();
+
+	return 0;
+}
-- 
2.7.4