diff options
Diffstat (limited to 'net/core/net_namespace.c')
| -rw-r--r-- | net/core/net_namespace.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index ce780c722e48..cb5290b8c428 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -15,6 +15,10 @@ #include <linux/file.h> #include <linux/export.h> #include <linux/user_namespace.h> +#include <linux/net_namespace.h> +#include <linux/rtnetlink.h> +#include <net/sock.h> +#include <net/netlink.h> #include <net/net_namespace.h> #include <net/netns/generic.h> @@ -144,6 +148,78 @@ static void ops_free_list(const struct pernet_operations *ops, } } +static int alloc_netid(struct net *net, struct net *peer, int reqid) +{ + int min = 0, max = 0; + + ASSERT_RTNL(); + + if (reqid >= 0) { + min = reqid; + max = reqid + 1; + } + + return idr_alloc(&net->netns_ids, peer, min, max, GFP_KERNEL); +} + +/* This function is used by idr_for_each(). If net is equal to peer, the + * function returns the id so that idr_for_each() stops. Because we cannot + * returns the id 0 (idr_for_each() will not stop), we return the magic value + * NET_ID_ZERO (-1) for it. + */ +#define NET_ID_ZERO -1 +static int net_eq_idr(int id, void *net, void *peer) +{ + if (net_eq(net, peer)) + return id ? : NET_ID_ZERO; + return 0; +} + +static int __peernet2id(struct net *net, struct net *peer, bool alloc) +{ + int id = idr_for_each(&net->netns_ids, net_eq_idr, peer); + + ASSERT_RTNL(); + + /* Magic value for id 0. */ + if (id == NET_ID_ZERO) + return 0; + if (id > 0) + return id; + + if (alloc) + return alloc_netid(net, peer, -1); + + return -ENOENT; +} + +/* This function returns the id of a peer netns. If no id is assigned, one will + * be allocated and returned. + */ +int peernet2id(struct net *net, struct net *peer) +{ + int id = __peernet2id(net, peer, true); + + return id >= 0 ? id : NETNSA_NSID_NOT_ASSIGNED; +} +EXPORT_SYMBOL(peernet2id); + +struct net *get_net_ns_by_id(struct net *net, int id) +{ + struct net *peer; + + if (id < 0) + return NULL; + + rcu_read_lock(); + peer = idr_find(&net->netns_ids, id); + if (peer) + get_net(peer); + rcu_read_unlock(); + + return peer; +} + /* * setup_net runs the initializers for the network namespace object. */ @@ -158,6 +234,7 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) atomic_set(&net->passive, 1); net->dev_base_seq = 1; net->user_ns = user_ns; + idr_init(&net->netns_ids); #ifdef NETNS_REFCNT_DEBUG atomic_set(&net->use_count, 0); @@ -288,6 +365,14 @@ static void cleanup_net(struct work_struct *work) list_for_each_entry(net, &net_kill_list, cleanup_list) { list_del_rcu(&net->list); list_add_tail(&net->exit_list, &net_exit_list); + for_each_net(tmp) { + int id = __peernet2id(tmp, net, false); + + if (id >= 0) + idr_remove(&tmp->netns_ids, id); + } + idr_destroy(&net->netns_ids); + } rtnl_unlock(); @@ -361,6 +446,7 @@ struct net *get_net_ns_by_fd(int fd) return ERR_PTR(-EINVAL); } #endif +EXPORT_SYMBOL_GPL(get_net_ns_by_fd); struct net *get_net_ns_by_pid(pid_t pid) { @@ -402,6 +488,130 @@ static struct pernet_operations __net_initdata net_ns_ops = { .exit = net_ns_net_exit, }; +static struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = { + [NETNSA_NONE] = { .type = NLA_UNSPEC }, + [NETNSA_NSID] = { .type = NLA_S32 }, + [NETNSA_PID] = { .type = NLA_U32 }, + [NETNSA_FD] = { .type = NLA_U32 }, +}; + +static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh) +{ + struct net *net = sock_net(skb->sk); + struct nlattr *tb[NETNSA_MAX + 1]; + struct net *peer; + int nsid, err; + + err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX, + rtnl_net_policy); + if (err < 0) + return err; + if (!tb[NETNSA_NSID]) + return -EINVAL; + nsid = nla_get_s32(tb[NETNSA_NSID]); + + if (tb[NETNSA_PID]) + peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); + else if (tb[NETNSA_FD]) + peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); + else + return -EINVAL; + if (IS_ERR(peer)) + return PTR_ERR(peer); + + if (__peernet2id(net, peer, false) >= 0) { + err = -EEXIST; + goto out; + } + + err = alloc_netid(net, peer, nsid); + if (err > 0) + err = 0; +out: + put_net(peer); + return err; +} + +static int rtnl_net_get_size(void) +{ + return NLMSG_ALIGN(sizeof(struct rtgenmsg)) + + nla_total_size(sizeof(s32)) /* NETNSA_NSID */ + ; +} + +static int rtnl_net_fill(struct sk_buff *skb, u32 portid, u32 seq, int flags, + int cmd, struct net *net, struct net *peer) +{ + struct nlmsghdr *nlh; + struct rtgenmsg *rth; + int id; + + ASSERT_RTNL(); + + nlh = nlmsg_put(skb, portid, seq, cmd, sizeof(*rth), flags); + if (!nlh) + return -EMSGSIZE; + + rth = nlmsg_data(nlh); + rth->rtgen_family = AF_UNSPEC; + + id = __peernet2id(net, peer, false); + if (id < 0) + id = NETNSA_NSID_NOT_ASSIGNED; + if (nla_put_s32(skb, NETNSA_NSID, id)) + goto nla_put_failure; + + nlmsg_end(skb, nlh); + return 0; + +nla_put_failure: + nlmsg_cancel(skb, nlh); + return -EMSGSIZE; +} + +static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh) +{ + struct net *net = sock_net(skb->sk); + struct nlattr *tb[NETNSA_MAX + 1]; + struct sk_buff *msg; + int err = -ENOBUFS; + struct net *peer; + + err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX, + rtnl_net_policy); + if (err < 0) + return err; + if (tb[NETNSA_PID]) + peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); + else if (tb[NETNSA_FD]) + peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); + else + return -EINVAL; + + if (IS_ERR(peer)) + return PTR_ERR(peer); + + msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL); + if (!msg) { + err = -ENOMEM; + goto out; + } + + err = rtnl_net_fill(msg, NETLINK_CB(skb).portid, nlh->nlmsg_seq, 0, + RTM_GETNSID, net, peer); + if (err < 0) + goto err_out; + + err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid); + goto out; + +err_out: + nlmsg_free(msg); +out: + put_net(peer); + return err; +} + static int __init net_ns_init(void) { struct net_generic *ng; @@ -435,6 +645,9 @@ static int __init net_ns_init(void) register_pernet_subsys(&net_ns_ops); + rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL, NULL); + rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, NULL, NULL); + return 0; } |