[PATCH] [RFC] C/R: inet4 and inet6 unicast routes (v2)
Dan Smith
danms at us.ibm.com
Fri Apr 30 10:00:55 PDT 2010
This patch adds support for checkpointing and restoring route information.
It keeps enough information to restore basic routes at the level of detail
of /proc/net/route. It uses RTNETLINK to extract the information during
checkpoint and also to insert it back during restore. This gives us a
nice layer of isolation between us and the various "fib" implementations.
Changes in v2:
This version of the patch actually moves the current task into the
desired network namespace temporarily, for the purposes of examining and
restoring the route information. This is a instead of creating a cross-
namespace socket to do the job, as was done in v1.
This is just an RFC to see if this is an acceptable method. For a final
version, adding a helper to nsproxy.c would allow us to create a new
nsproxy with the desired netns instead of creating one with
copy_namespaces() just to kill it off and use the target one.
I still think the previous method is cleaner, but this way may violate
fewer namespace boundaries (I'm still undecided :)
Signed-off-by: Dan Smith <danms at us.ibm.com>
Cc: David Miller <davem at davemloft.net>
Cc: Vlad Yasevich <vladislav.yasevich at hp.com>
Cc: jamal <hadi at cyberus.ca>
---
include/linux/checkpoint_hdr.h | 31 +++
net/checkpoint_dev.c | 463 +++++++++++++++++++++++++++++++++++++++-
2 files changed, 493 insertions(+), 1 deletions(-)
diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
index 790214f..28b268a 100644
--- a/include/linux/checkpoint_hdr.h
+++ b/include/linux/checkpoint_hdr.h
@@ -20,6 +20,7 @@
#ifndef CONFIG_CHECKPOINT
#warn linux/checkpoint_hdr.h included directly (without CONFIG_CHECKPOINT)
#endif
+#include <linux/if.h>
#else /* __KERNEL__ */
@@ -782,6 +783,7 @@ struct ckpt_hdr_file_socket {
struct ckpt_hdr_netns {
struct ckpt_hdr h;
__s32 this_ref;
+ __u32 routes;
} __attribute__((aligned(8)));
enum ckpt_netdev_types {
@@ -826,6 +828,35 @@ struct ckpt_netdev_addr {
} __attribute__((aligned(8)));
} __attribute__((aligned(8)));
+enum ckpt_route_types {
+ CKPT_ROUTE_IPV4,
+ CKPT_ROUTE_IPV6,
+ CKPT_ROUTE_MAX
+};
+
+#define CKPT_ROUTE_FLAG_GW 1
+
+struct ckpt_route {
+ __u16 type;
+ __u16 flags;
+
+ union {
+ struct {
+ __be32 inet4_len; /* mask length (bits) */
+ __u32 inet4_met; /* metric */
+ __be32 inet4_dst; /* route address */
+ __be32 inet4_gwy; /* gateway address */
+ };
+ struct {
+ __u32 inet6_len; /* mask length (bits) */
+ __u32 inet6_met; /* metric */
+ struct in6_addr inet6_dst; /* route address */
+ struct in6_addr inet6_gwy; /* gateway address */
+ };
+ } __attribute__((aligned(8)));
+ char dev[IFNAMSIZ+1];
+} __attribute__((aligned(8)));
+
struct ckpt_hdr_eventpoll_items {
struct ckpt_hdr h;
__s32 epfile_objref;
diff --git a/net/checkpoint_dev.c b/net/checkpoint_dev.c
index a8e3341..cc5f0ac 100644
--- a/net/checkpoint_dev.c
+++ b/net/checkpoint_dev.c
@@ -16,9 +16,11 @@
#include <linux/veth.h>
#include <linux/checkpoint.h>
#include <linux/deferqueue.h>
+#include <linux/fib_rules.h>
#include <net/net_namespace.h>
#include <net/sch_generic.h>
+#include <net/ipv6.h>
struct veth_newlink {
char *peer;
@@ -59,6 +61,22 @@ static int __kern_dev_ioctl(struct net *net, unsigned int cmd, void *arg)
return ret;
}
+static void debug_route(struct ckpt_route *route)
+{
+ if (route->type == CKPT_ROUTE_IPV4)
+ ckpt_debug("inet4 route %pI4/%i gw %pI4 metric %i dev %s\n",
+ &route->inet4_dst, route->inet4_len,
+ &route->inet4_gwy, route->inet4_met,
+ route->dev);
+ else if (route->type == CKPT_ROUTE_IPV6)
+ ckpt_debug("inet6 route %pI6/%i gw %pI6 metric %i dev %s\n",
+ &route->inet6_dst, route->inet6_len,
+ &route->inet6_gwy, route->inet6_met,
+ route->dev);
+ else
+ ckpt_debug("unknown route type %i\n", route->type);
+}
+
static struct socket *rtnl_open(void)
{
struct socket *sock;
@@ -250,11 +268,280 @@ int checkpoint_netdev(struct ckpt_ctx *ctx, void *ptr)
return ret;
}
+static int rtnl_do_dump_routes(struct socket *rtnl, int family)
+{
+ struct sk_buff *skb = NULL;
+ struct rtmsg *rtm;
+ int flags = NLM_F_ROOT | NLM_F_REQUEST;
+ struct msghdr msg;
+ struct kvec kvec;
+ struct nlmsghdr *nlh;
+ int ret = -ENOMEM;
+
+ skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+ if (!skb)
+ return -ENOMEM;
+
+ nlh = nlmsg_put(skb, 0, 0, RTM_GETROUTE, sizeof(*rtm), flags);
+ if (!nlh)
+ goto out;
+
+ rtm = nlmsg_data(nlh);
+ memset(rtm, 0, sizeof(*rtm));
+ rtm->rtm_family = family;
+
+ nlmsg_end(skb, nlh);
+
+ memset(&msg, 0, sizeof(msg));
+ kvec.iov_len = skb->len;
+ kvec.iov_base = skb->head;
+
+ ret = kernel_sendmsg(rtnl, &msg, &kvec, 1, kvec.iov_len);
+ if ((ret >= 0) && (ret != skb->len))
+ ret = -EIO;
+ out:
+ kfree_skb(skb);
+
+ return ret;
+}
+
+static int rtnl_dump_routes(struct socket *rtnl, int family,
+ struct sk_buff **skb)
+{
+ int ret = -ENOMEM;
+ long timeo = MAX_SCHEDULE_TIMEOUT;
+
+ *skb = NULL;
+
+ ret = rtnl_do_dump_routes(rtnl, family);
+ if (ret < 0)
+ return ret;
+
+ lock_sock(rtnl->sk);
+ ret = sk_wait_data(rtnl->sk, &timeo);
+ if (ret)
+ *skb = skb_dequeue(&rtnl->sk->sk_receive_queue);
+ release_sock(rtnl->sk);
+ if (!*skb)
+ ret = -EIO;
+
+ return ret;
+}
+
+static int rtnl_process_inet4_route(struct net *net,
+ struct rtmsg *rtm,
+ struct nlattr **tb,
+ struct ckpt_route *route)
+{
+ if (rtm->rtm_type != RTN_UNICAST)
+ return 0; /* skip non-unicast routes */
+
+ route->type = CKPT_ROUTE_IPV4;
+ route->inet4_len = rtm->rtm_dst_len;
+
+ if (tb[RTA_DST])
+ route->inet4_dst = htonl(nla_get_u32(tb[RTA_DST]));
+ if (tb[RTA_GATEWAY]) {
+ route->flags |= CKPT_ROUTE_FLAG_GW;
+ route->inet4_gwy = htonl(nla_get_u32(tb[RTA_GATEWAY]));
+ }
+ if (tb[RTA_PRIORITY])
+ route->inet4_met = nla_get_u32(tb[RTA_PRIORITY]);
+
+ if (tb[RTA_OIF]) {
+ struct net_device *dev;
+
+ dev = dev_get_by_index(net, nla_get_u32(tb[RTA_OIF]));
+ if (dev) {
+ strncpy(route->dev, dev->name, IFNAMSIZ);
+ dev_put(dev);
+ }
+ }
+
+ debug_route(route);
+
+ return 1; /* save this route */
+}
+
+static int rtnl_process_inet6_route(struct net *net,
+ struct rtmsg *rtm,
+ struct nlattr **tb,
+ struct ckpt_route *route)
+{
+ if (rtm->rtm_type != RTN_UNICAST)
+ return 0; /* skip non-unicast routes */
+
+ route->type = CKPT_ROUTE_IPV6;
+ route->inet6_len = rtm->rtm_dst_len;
+
+ if (tb[RTA_DST])
+ ipv6_addr_copy(&route->inet6_dst, nla_data(tb[RTA_DST]));
+ if (tb[RTA_GATEWAY]) {
+ route->flags |= CKPT_ROUTE_FLAG_GW;
+ ipv6_addr_copy(&route->inet6_gwy, nla_data(tb[RTA_GATEWAY]));
+ }
+ if (tb[RTA_PRIORITY])
+ route->inet6_met = nla_get_u32(tb[RTA_PRIORITY]);
+
+ if (tb[RTA_OIF]) {
+ struct net_device *dev;
+
+ dev = dev_get_by_index(net, nla_get_u32(tb[RTA_OIF]));
+ if (dev) {
+ strncpy(route->dev, dev->name, IFNAMSIZ);
+ dev_put(dev);
+ }
+ }
+
+ debug_route(route);
+
+ return 1;
+}
+
+static int rtnl_process_routes(struct net *net,
+ struct nlmsghdr *nlh, int len,
+ struct ckpt_route *routes,
+ int idx, int max)
+{
+ struct nlmsghdr *i;
+
+ for (i = nlh; NLMSG_OK(i, len); i = NLMSG_NEXT(i, len)) {
+ struct ckpt_route *route = &routes[idx];
+ struct rtmsg *rtm = NLMSG_DATA(i);
+ struct nlattr *tb[FRA_MAX+1];
+ int ret;
+
+ if (idx >= max)
+ return -E2BIG;
+
+ if (i->nlmsg_type == NLMSG_DONE)
+ break;
+ else if (nlh->nlmsg_type != RTM_NEWROUTE) {
+ struct nlmsgerr *errmsg = nlmsg_data(nlh);
+ return errmsg->error;
+ }
+
+ ret = nlmsg_parse(i, sizeof(*rtm), tb, FRA_MAX, NULL);
+ if (ret < 0)
+ return ret;
+
+ memset(route, 0, sizeof(*route));
+
+ if (rtm->rtm_family == AF_INET)
+ ret = rtnl_process_inet4_route(net, rtm, tb, route);
+ else if (rtm->rtm_family == AF_INET6)
+ ret = rtnl_process_inet6_route(net, rtm, tb, route);
+ else
+ ret = 0; /* skip */
+ if (ret < 0)
+ return ret;
+ else if (ret)
+ idx += 1;
+ }
+
+ return idx;
+}
+
+static int temp_netns_enter(struct net *net)
+{
+ int ret;
+ struct net *tmp_netns;
+
+ ret = copy_namespaces(CLONE_NEWNET, current);
+ if (ret)
+ return ret;
+
+ tmp_netns = current->nsproxy->net_ns;
+ get_net(net);
+ current->nsproxy->net_ns = net;
+ put_net(tmp_netns);
+
+ return 0;
+}
+
+static void temp_netns_exit(struct nsproxy *prev)
+{
+ switch_task_namespaces(current, prev);
+}
+
+static int rtnl_get_routes(struct net *net, int family,
+ struct ckpt_route *routes, int idx, int max)
+{
+ int ret;
+ struct nlmsghdr *nlh;
+ struct sk_buff *skb = NULL;
+ struct socket *rtnl = NULL;
+ struct nsproxy *prev = current->nsproxy;
+
+ ret = temp_netns_enter(net);
+ if (ret)
+ return ret;
+
+ rtnl = rtnl_open();
+ if (IS_ERR(rtnl)) {
+ ret = PTR_ERR(rtnl);
+ goto out;
+ }
+
+ ret = rtnl_dump_routes(rtnl, family, &skb);
+ if (ret < 0)
+ goto out;
+
+ nlh = nlmsg_hdr(skb);
+ if (!nlh) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = rtnl_process_routes(net, nlh, skb->len, routes, idx, max);
+ out:
+ kfree_skb(skb);
+ rtnl_close(rtnl);
+ temp_netns_exit(prev);
+
+ return ret;
+}
+
+int checkpoint_netns_routes(struct ckpt_ctx *ctx, struct net *net,
+ struct ckpt_route **_routes)
+{
+ struct ckpt_route *routes = NULL;
+ int max = 32;
+ int idx;
+ int families[] = {AF_INET, AF_INET6, 0};
+ int family;
+ retry:
+ idx = 0;
+ kfree(routes);
+ routes = kmalloc(max * sizeof(*routes), GFP_KERNEL);
+ if (!routes)
+ return -ENOMEM;
+
+ for (family = 0; families[family]; family++) {
+ idx = rtnl_get_routes(net, families[family], routes, idx, max);
+ if (idx == -E2BIG) {
+ max *= 2;
+ goto retry;
+ } else if (idx < 0)
+ break;
+ }
+
+ if (idx < 0) {
+ kfree(routes);
+ routes = NULL;
+ ckpt_err(ctx, idx, "error saving routes\n");
+ }
+ *_routes = routes;
+
+ return idx;
+}
+
int checkpoint_netns(struct ckpt_ctx *ctx, void *ptr)
{
struct net *net = ptr;
struct net_device *dev;
struct ckpt_hdr_netns *h;
+ struct ckpt_route *routes = NULL;
int ret;
h = ckpt_hdr_get_type(ctx, sizeof(*h), CKPT_HDR_NET_NS);
@@ -264,10 +551,19 @@ int checkpoint_netns(struct ckpt_ctx *ctx, void *ptr)
h->this_ref = ckpt_obj_lookup(ctx, net, CKPT_OBJ_NET_NS);
BUG_ON(h->this_ref <= 0);
+ ret = checkpoint_netns_routes(ctx, net, &routes);
+ if (ret < 0)
+ goto out;
+ h->routes = ret;
+
ret = ckpt_write_obj(ctx, (struct ckpt_hdr *) h);
if (ret < 0)
goto out;
+ ret = ckpt_write_buffer(ctx, routes, h->routes * sizeof(*routes));
+ if (ret < 0)
+ goto out;
+
for_each_netdev(net, dev) {
if (dev->netdev_ops->ndo_checkpoint)
ret = checkpoint_obj(ctx, dev, CKPT_OBJ_NETDEV);
@@ -284,6 +580,7 @@ int checkpoint_netns(struct ckpt_ctx *ctx, void *ptr)
}
out:
ckpt_hdr_put(ctx, h);
+ kfree(routes);
return ret;
}
@@ -825,10 +1122,152 @@ void *restore_netdev(struct ckpt_ctx *ctx)
return dev;
}
+static int rtnl_restore_route(struct net *net, struct ckpt_route *route)
+{
+ struct sk_buff *skb;
+ struct rtmsg *rtm;
+ int flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_ACK;
+ struct nlmsghdr *nlh;
+ int ret = 0;
+
+ skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+ if (!skb)
+ return -ENOMEM;
+
+ nlh = nlmsg_put(skb, 0, 0, RTM_NEWROUTE, sizeof(*rtm), flags);
+ if (!nlh) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ rtm = nlmsg_data(nlh);
+ memset(rtm, 0, sizeof(*rtm));
+
+ rtm->rtm_table = RT_TABLE_MAIN;
+ rtm->rtm_protocol = RTPROT_BOOT;
+ rtm->rtm_scope = RT_SCOPE_UNIVERSE;
+ rtm->rtm_type = RTN_UNICAST;
+
+ if (route->dev[0]) {
+ struct net_device *dev;
+
+ dev = dev_get_by_name(net, route->dev);
+ if (!dev) {
+ ckpt_debug("unable to find dev %s for route\n",
+ route->dev);
+ ret = -EINVAL;
+ goto out;
+ }
+ nla_put_u32(skb, RTA_OIF, dev->ifindex);
+ dev_put(dev);
+ }
+
+ if (route->type == CKPT_ROUTE_IPV4) {
+ rtm->rtm_family = AF_INET;
+ rtm->rtm_dst_len = route->inet4_len;
+
+ nla_put_u32(skb, RTA_DST, ntohl(route->inet4_dst));
+ if (route->flags & CKPT_ROUTE_FLAG_GW)
+ nla_put_u32(skb, RTA_GATEWAY, ntohl(route->inet4_gwy));
+ nla_put_u32(skb, RTA_PRIORITY, route->inet4_met);
+ } else if (route->type == CKPT_ROUTE_IPV6) {
+ int len = sizeof(route->inet6_dst);
+
+ if (ipv6_addr_scope(&route->inet6_dst))
+ goto out; /* Skip non-global scope routes */
+
+ rtm->rtm_family = AF_INET6;
+ rtm->rtm_dst_len = route->inet6_len;
+
+ nla_put(skb, RTA_DST, len, &route->inet6_dst);
+ if (route->flags & CKPT_ROUTE_FLAG_GW)
+ nla_put(skb, RTA_GATEWAY, len, &route->inet6_gwy);
+ nla_put_u32(skb, RTA_PRIORITY, route->inet6_met);
+ } else {
+ ckpt_debug("unsupported route type %i\n", route->type);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ nlmsg_end(skb, nlh);
+
+ debug_route(route);
+
+ ret = rtnl_do(skb);
+ out:
+ kfree_skb(skb);
+ return ret;
+}
+
+static int restore_routes(struct net *net, struct ckpt_route *routes, int count)
+{
+ int i;
+ int ret = 0;
+ struct nsproxy *prev = current->nsproxy;
+
+ ret = temp_netns_enter(net);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < count; i++) {
+ struct ckpt_route *route = &routes[i];
+
+ ret = rtnl_restore_route(net, route);
+ if (ret == -EEXIST)
+ /* Some routes have been implied by device addresses */
+ continue;
+ else if (ret < 0)
+ break;
+ }
+
+ temp_netns_exit(prev);
+
+ return ret;
+}
+
+struct dq_routes {
+ struct ckpt_ctx *ctx;
+ struct net *net;
+ struct ckpt_route *routes;
+ int count;
+};
+
+static int deferred_restore_routes(void *data)
+{
+ struct dq_routes *dq = data;
+ int ret;
+
+ ret = restore_routes(dq->net, dq->routes, dq->count);
+ if (ret < 0)
+ ckpt_err(dq->ctx, ret, "failed to restore routes\n");
+
+ kfree(dq->routes);
+
+ return ret;
+}
+
+static int defer_restore_routes(struct ckpt_ctx *ctx,
+ struct net *net,
+ struct ckpt_route *routes,
+ int count)
+{
+ struct dq_routes dq;
+
+ dq.ctx = ctx;
+ dq.net = net;
+ dq.routes = routes;
+ dq.count = count;
+
+ return deferqueue_add(ctx->deferqueue, &dq, sizeof(dq),
+ deferred_restore_routes, NULL);
+}
+
void *restore_netns(struct ckpt_ctx *ctx)
{
struct ckpt_hdr_netns *h;
struct net *net;
+ struct ckpt_route *routes = NULL;
+ int ret;
h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_NET_NS);
if (IS_ERR(h)) {
@@ -836,12 +1275,34 @@ void *restore_netns(struct ckpt_ctx *ctx)
return h;
}
+ ret = ckpt_read_payload(ctx, (void **)&routes,
+ h->routes * sizeof(*routes), CKPT_HDR_BUFFER);
+ if (ret < 0) {
+ ckpt_err(ctx, ret, "Unable to read routes buffer\n");
+ net = ERR_PTR(ret);
+ goto out;
+ }
+
if (h->this_ref != 0) {
net = copy_net_ns(CLONE_NEWNET, current->nsproxy->net_ns);
if (IS_ERR(net))
goto out;
- } else
+
+ ret = defer_restore_routes(ctx, net, routes, h->routes);
+ if (ret < 0) {
+ kfree(routes);
+ put_net(net);
+ net = ERR_PTR(ret);
+ }
+ } else {
+ if (h->routes) {
+ net = ERR_PTR(-EINVAL);
+ ckpt_err(ctx, -EINVAL,
+ "Parent netns claims to have routes\n");
+ goto out;
+ }
net = current->nsproxy->net_ns;
+ }
out:
ckpt_hdr_put(ctx, h);
--
1.6.2.5
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