This patch takes advantage of the newly added lwtunnel framework to
allow the user to set routes that points to a peer netns.
Packets are injected to the peer netns via the loopback device. It works
only when the output device is 'lo'.
Example:
ip route add 40.1.1.1/32 encap netns nsid 5 via dev lo
Signed-off-by: Nicolas Dichtel <nicolas.dich...@6wind.com>
---
drivers/net/loopback.c | 16 +++++++++++++
include/net/lwtunnel.h | 23 +++++++++++++++++++
include/uapi/linux/lwtunnel.h | 1 +
net/core/net_namespace.c | 52 +++++++++++++++++++++++++++++++++++++++++++
4 files changed, 92 insertions(+)
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index c76283c2f84a..758d02f592f9 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -57,6 +57,7 @@
#include <linux/percpu.h>
#include <net/net_namespace.h>
#include <linux/u64_stats_sync.h>
+#include <net/lwtunnel.h>
struct pcpu_lstats {
u64 packets;
@@ -71,9 +72,23 @@ struct pcpu_lstats {
static netdev_tx_t loopback_xmit(struct sk_buff *skb,
struct net_device *dev)
{
+ int nsid = skb_lwt_netns_info(skb);
struct pcpu_lstats *lb_stats;
int len;
+ if (nsid >= 0) {
+ struct net *peernet = get_net_ns_by_id(dev_net(dev), nsid);
+
+ if (!peernet) {
+ kfree_skb(skb);
+ goto end;
+ }
+
+ dev_forward_skb(peernet->loopback_dev, skb);
+ put_net(peernet);
+ goto end;
+ }
+
skb_orphan(skb);
/* Before queueing this packet to netif_rx(),
@@ -94,6 +109,7 @@ static netdev_tx_t loopback_xmit(struct sk_buff *skb,
u64_stats_update_end(&lb_stats->syncp);
}
+end:
return NETDEV_TX_OK;
}
diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h
index 918e03c1dafa..cc05ce3c1aae 100644
--- a/include/net/lwtunnel.h
+++ b/include/net/lwtunnel.h
@@ -5,7 +5,9 @@
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/types.h>
+#include <linux/net_namespace.h>
#include <net/route.h>
+#include <net/ip6_fib.h>
#define LWTUNNEL_HASH_BITS 7
#define LWTUNNEL_HASH_SIZE (1 << LWTUNNEL_HASH_BITS)
@@ -141,4 +143,25 @@ static inline int lwtunnel_output6(struct sock *sk, struct
sk_buff *skb)
#endif
+static inline u32 *lwt_netns_info(struct lwtunnel_state *lwtstate)
+{
+ return (u32 *)lwtstate->data;
+}
+
+static inline int skb_lwt_netns_info(struct sk_buff *skb)
+{
+ if (skb->protocol == htons(ETH_P_IP)) {
+ struct rtable *rt = (struct rtable *)skb_dst(skb);
+
+ if (rt && rt->rt_lwtstate)
+ return *lwt_netns_info(rt->rt_lwtstate);
+ } else if (skb->protocol == htons(ETH_P_IPV6)) {
+ struct rt6_info *rt6 = (struct rt6_info *)skb_dst(skb);
+
+ if (rt6 && rt6->rt6i_lwtstate)
+ return *lwt_netns_info(rt6->rt6i_lwtstate);
+ }
+
+ return NETNSA_NSID_NOT_ASSIGNED;
+}
#endif /* __NET_LWTUNNEL_H */
diff --git a/include/uapi/linux/lwtunnel.h b/include/uapi/linux/lwtunnel.h
index 31377bbea3f8..6715e7a1b335 100644
--- a/include/uapi/linux/lwtunnel.h
+++ b/include/uapi/linux/lwtunnel.h
@@ -7,6 +7,7 @@ enum lwtunnel_encap_types {
LWTUNNEL_ENCAP_NONE,
LWTUNNEL_ENCAP_MPLS,
LWTUNNEL_ENCAP_IP,
+ LWTUNNEL_ENCAP_NETNS,
__LWTUNNEL_ENCAP_MAX,
};
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 2c2eb1b629b1..c1267aac373d 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -20,6 +20,7 @@
#include <net/netlink.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
+#include <net/lwtunnel.h>
/*
* Our network namespace constructor/destructor lists
@@ -725,6 +726,56 @@ out:
rtnl_set_sk_err(net, RTNLGRP_NSID, err);
}
+static int lwt_netns_build_state(struct net_device *dev, struct nlattr *nla,
+ struct lwtunnel_state **ts)
+{
+ struct nlattr *tb[NETNSA_MAX + 1];
+ struct lwtunnel_state *newts;
+ int *nsid;
+ int ret;
+
+ ret = nla_parse_nested(tb, NETNSA_MAX, nla, rtnl_net_policy);
+ if (ret < 0)
+ return ret;
+
+ if (!tb[NETNSA_NSID])
+ return -EINVAL;
+
+ newts = lwtunnel_state_alloc(sizeof(*nsid));
+ if (!newts)
+ return -ENOMEM;
+
+ newts->len = sizeof(*nsid);
+ nsid = lwt_netns_info(newts);
+ *nsid = nla_get_s32(tb[NETNSA_NSID]);
+ newts->type = LWTUNNEL_ENCAP_NETNS;
+
+ *ts = newts;
+ return 0;
+}
+
+static int lwt_netns_fill_encap_info(struct sk_buff *skb,
+ struct lwtunnel_state *lwtstate)
+{
+ int *nsid = lwt_netns_info(lwtstate);
+
+ if (nla_put_s32(skb, NETNSA_NSID, *nsid))
+ return -ENOMEM;
+
+ return 0;
+}
+
+static int lwt_netns_encap_nlsize(struct lwtunnel_state *lwtstate)
+{
+ return nla_total_size(4); /* NETNSA_NSID */
+}
+
+static const struct lwtunnel_encap_ops lwt_netns_ops = {
+ .build_state = lwt_netns_build_state,
+ .fill_encap = lwt_netns_fill_encap_info,
+ .get_encap_size = lwt_netns_encap_nlsize,
+};
+
static int __init net_ns_init(void)
{
struct net_generic *ng;
@@ -762,6 +813,7 @@ static int __init net_ns_init(void)
rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid,
NULL);
+ lwtunnel_encap_add_ops(&lwt_netns_ops, LWTUNNEL_ENCAP_NETNS);
return 0;
}
--
2.4.2
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