[CRIU] [PATCH 06/10] net: create a parasite socket for each network namespace

[Andrei Vagin]

From: Andrei Vagin <avagin at virtuozzo.com>

CRIU uses an unix socket to comunicate with a parasite code,
but an unix socket created from one netns is invisible
from another netns.

Signed-off-by: Andrei Vagin <avagin at virtuozzo.com>
---
 criu/include/parasite.h |  2 ++
 criu/net.c              | 27 +++++++++++++++++++++------
 criu/parasite-syscall.c | 22 +++-------------------
 3 files changed, 26 insertions(+), 25 deletions(-)

diff --git a/criu/include/parasite.h b/criu/include/parasite.h
index 7211477..e26b7f0 100644
--- a/criu/include/parasite.h
+++ b/criu/include/parasite.h
@@ -275,6 +275,8 @@ struct parasite_dump_cgroup_args {
 #define parasite_sym(pblob, ptype, symbol)				\
 	((void *)(pblob) + __pblob_offset(ptype, symbol))
 
+extern int gen_parasite_saddr(struct sockaddr_un *saddr, int key);
+
 #endif /* !__ASSEMBLY__ */
 
 #include "parasite-compat.h"
diff --git a/criu/net.c b/criu/net.c
index e4a7627..7a50640 100644
--- a/criu/net.c
+++ b/criu/net.c
@@ -29,6 +29,7 @@
 #include "string.h"
 #include "sysctl.h"
 #include "kerndat.h"
+#include "parasite.h"
 
 #include "protobuf.h"
 #include "images/netdev.pb-c.h"
@@ -1661,7 +1662,9 @@ int veth_pair_add(char *in, char *out)
 
 static int prep_ns_sockets(struct ns_id *ns, bool for_dump)
 {
-	int nsret = -1, ret;
+	int nsret = -1, ret, sk;
+	struct sockaddr_un addr;
+	s32 addr_len;
 
 	if (ns->type != NS_CRIU) {
 		pr_info("Switching to %d's net for collecting sockets\n", ns->ns_pid);
@@ -1678,12 +1681,24 @@ static int prep_ns_sockets(struct ns_id *ns, bool for_dump)
 	} else
 		ns->net.nlsk = -1;
 
-	ret = ns->net.seqsk = socket(PF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK, 0);
-	if (ret < 0) {
+	sk = socket(PF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK, 0);
+	if (sk < 0) {
 		pr_perror("Can't create seqsk for parasite");
 		goto err_sq;
 	}
 
+	addr_len = gen_parasite_saddr(&addr, getpid());
+	if (bind(sk, (struct sockaddr *)&addr, addr_len) < 0) {
+		pr_perror("Can't bind socket");
+		goto err_ret;
+	}
+
+	if (listen(sk, 1)) {
+		pr_perror("Can't listen on transport socket");
+		goto err_ret;
+	}
+
+	ns->net.seqsk = sk;
 	ret = 0;
 out:
 	if (nsret >= 0 && restore_ns(nsret, &net_ns_desc) < 0) {
@@ -1695,11 +1710,11 @@ out:
 	return ret;
 
 err_ret:
-	close(ns->net.seqsk);
+	close_safe(&sk);
 err_sq:
-	if (ns->net.nlsk >= 0)
-		close(ns->net.nlsk);
+	close_safe(&ns->net.nlsk);
 err_nl:
+	ret = -1;
 	goto out;
 }
 
diff --git a/criu/parasite-syscall.c b/criu/parasite-syscall.c
index fb1c245..18923a5 100644
--- a/criu/parasite-syscall.c
+++ b/criu/parasite-syscall.c
@@ -363,7 +363,7 @@ int parasite_execute_daemon(unsigned int cmd, struct parasite_ctl *ctl)
 	return ret;
 }
 
-static int gen_parasite_saddr(struct sockaddr_un *saddr, int key)
+int gen_parasite_saddr(struct sockaddr_un *saddr, int key)
 {
 	int sun_len;
 
@@ -454,25 +454,12 @@ static int restore_child_handler()
 static int prepare_tsock(struct parasite_ctl *ctl, pid_t pid,
 		struct parasite_init_args *args, struct ns_id *net)
 {
-	static int ssock = -1;
+	int ssock;
 
 	pr_info("Putting tsock into pid %d\n", pid);
 	args->h_addr_len = gen_parasite_saddr(&args->h_addr, getpid());
 
-	if (ssock == -1) {
-		ssock = net->net.seqsk;
-		net->net.seqsk = -1;
-
-		if (bind(ssock, (struct sockaddr *)&args->h_addr, args->h_addr_len) < 0) {
-			pr_perror("Can't bind socket");
-			goto err;
-		}
-
-		if (listen(ssock, 1)) {
-			pr_perror("Can't listen on transport socket");
-			goto err;
-		}
-	}
+	ssock = net->net.seqsk;
 
 	/* Check a case when parasite can't initialize a command socket */
 	if (fault_injected(FI_PARASITE_CONNECT))
@@ -484,9 +471,6 @@ static int prepare_tsock(struct parasite_ctl *ctl, pid_t pid,
 	 */
 	ctl->tsock = -ssock;
 	return 0;
-err:
-	close_safe(&ssock);
-	return -1;
 }
 
 static int accept_tsock(struct parasite_ctl *ctl)
-- 
2.7.4