[CRIU] [PATCH CRIU 08/14] restore/net/ipv6: net device and def/all configuration

[Pavel Tikhomirov]

First restore "all" and then "default"(and "dev") as for some ipv6
sysctls setting all can change the latter(forwarding, disable_ipv6)

e.g.:
 echo 1 > /proc/sys/net/ipv6/conf/default/disable_ipv6
 echo 0 > /proc/sys/net/ipv6/conf/all/disable_ipv6
 cat /proc/sys/net/ipv6/conf/default/disable_ipv6
0

As changing disable_ipv6 sysctl for some device may change mtu sysctl
do not optimize mtu's restore.

https://jira.sw.ru/browse/PSBM-30942
Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
---
 criu/net.c | 40 ++++++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 10 deletions(-)

diff --git a/criu/net.c b/criu/net.c
index a55cfba..b1753d9 100644
--- a/criu/net.c
+++ b/criu/net.c
@@ -163,9 +163,11 @@ static int net_conf_op(char *tgt, int *conf, int n, int op, char *proto,
 			continue;
 		}
 		/*
-		 * If dev conf value is the same as default skip restoring it
+		 * If dev conf value is the same as default skip restoring it,
+		 * mtu may be changed by disable_ipv6 so we can not skip
+		 * it's restore
 		 */
-		if (def_conf && conf[i] == def_conf[i]) {
+		if (def_conf && conf[i] == def_conf[i] && strcmp(devconfs[i], "mtu")) {
 			pr_debug("DEBUG Skip %s/%s, val =%d\n", tgt, devconfs[i], conf[i]);
 			continue;
 		}
@@ -833,6 +835,8 @@ static int restore_links(int pid, NetnsEntry **netns)
 	}
 
 	while (1) {
+		NetnsEntry **def_netns = netns;
+
 		ret = pb_read_one_eof(img, &nde, PB_NETDEV);
 		if (ret <= 0)
 			break;
@@ -843,18 +847,24 @@ static int restore_links(int pid, NetnsEntry **netns)
 			goto exit;
 		}
 
+		/*
+		 * optimize restore of devices configuration except lo
+		 * lo is created with namespace and before default is set
+		 * so we cant optimize its restore
+		 */
+		if (nde->type == ND_TYPE__LOOPBACK)
+			def_netns = NULL;
+
 		if (nde->conf4) {
-			NetnsEntry **def_netns = netns;
-			/*
-			 * optimize restore of devices configuration except lo
-			 * lo is created with namespace and before default is set
-			 * so we cant optimize its restore
-			 */
-			if (nde->type == ND_TYPE__LOOPBACK)
-				def_netns = NULL;
 			ret = ipv4_conf_op(nde->name, nde->conf4, nde->n_conf4,
 					CTL_WRITE, nde->mask_unused4, def_netns);
+			if (ret)
+				goto exit;
 		}
+
+		if (nde->conf6)
+			ret = ipv6_conf_op(nde->name, nde->conf6, nde->n_conf6,
+					CTL_WRITE, nde->mask_unused6, def_netns);
 exit:
 		net_device_entry__free_unpacked(nde, NULL);
 		if (ret)
@@ -1150,6 +1160,16 @@ static int restore_netns_conf(int pid, NetnsEntry **netns)
 		goto out;
 	ret = ipv4_conf_op("all", (*netns)->all_conf4, n,
 			CTL_WRITE, (*netns)->mask_unused4, NULL);
+
+	if ((*netns)->def_conf6) {
+		n = (*netns)->n_def_conf6;
+		ret = ipv6_conf_op("all", (*netns)->all_conf6, n,
+				CTL_WRITE, (*netns)->mask_unused6, NULL);
+		if (ret)
+			goto out;
+		ret = ipv6_conf_op("default", (*netns)->def_conf6, n,
+				CTL_WRITE, (*netns)->mask_unused6, NULL);
+	}
 out:
 	close_image(img);
 	return ret;
-- 
1.9.3