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mptcp: create the listening socket for new port
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This patch creates a listening socket when an address with a port-number
is added by PM netlink. Then binds the new port to the socket, and
listens for new connections.

When the address is removed or the addresses are flushed by PM netlink,
release the listening socket.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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geliangtang authored and kuba-moo committed Feb 3, 2021
1 parent 6208fd8 commit 1729cf1
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Showing 4 changed files with 102 additions and 6 deletions.
96 changes: 94 additions & 2 deletions net/mptcp/pm_netlink.c
Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@ struct mptcp_pm_addr_entry {
struct list_head list;
struct mptcp_addr_info addr;
struct rcu_head rcu;
struct socket *lsk;
};

struct mptcp_pm_add_entry {
Expand Down Expand Up @@ -678,6 +679,53 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
return ret;
}

static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
struct mptcp_pm_addr_entry *entry)
{
struct sockaddr_storage addr;
struct mptcp_sock *msk;
struct socket *ssock;
int backlog = 1024;
int err;

err = sock_create_kern(sock_net(sk), entry->addr.family,
SOCK_STREAM, IPPROTO_MPTCP, &entry->lsk);
if (err)
return err;

msk = mptcp_sk(entry->lsk->sk);
if (!msk) {
err = -EINVAL;
goto out;
}

ssock = __mptcp_nmpc_socket(msk);
if (!ssock) {
err = -EINVAL;
goto out;
}

mptcp_info2sockaddr(&entry->addr, &addr, entry->addr.family);
err = kernel_bind(ssock, (struct sockaddr *)&addr,
sizeof(struct sockaddr_in));
if (err) {
pr_warn("kernel_bind error, err=%d", err);
goto out;
}

err = kernel_listen(ssock, backlog);
if (err) {
pr_warn("kernel_listen error, err=%d", err);
goto out;
}

return 0;

out:
sock_release(entry->lsk);
return err;
}

int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
{
struct mptcp_pm_addr_entry *entry;
Expand Down Expand Up @@ -722,6 +770,8 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
entry->addr.ifindex = 0;
entry->addr.flags = 0;
entry->addr.id = 0;
entry->addr.port = 0;
entry->lsk = NULL;
ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
if (ret < 0)
kfree(entry);
Expand Down Expand Up @@ -891,9 +941,19 @@ static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
}

*entry = addr;
if (entry->addr.port) {
ret = mptcp_pm_nl_create_listen_socket(skb->sk, entry);
if (ret) {
GENL_SET_ERR_MSG(info, "create listen socket error");
kfree(entry);
return ret;
}
}
ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
if (ret < 0) {
GENL_SET_ERR_MSG(info, "too many addresses or duplicate one");
if (entry->lsk)
sock_release(entry->lsk);
kfree(entry);
return ret;
}
Expand Down Expand Up @@ -977,6 +1037,38 @@ static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
return 0;
}

struct addr_entry_release_work {
struct rcu_work rwork;
struct mptcp_pm_addr_entry *entry;
};

static void mptcp_pm_release_addr_entry(struct work_struct *work)
{
struct addr_entry_release_work *w;
struct mptcp_pm_addr_entry *entry;

w = container_of(to_rcu_work(work), struct addr_entry_release_work, rwork);
entry = w->entry;
if (entry) {
if (entry->lsk)
sock_release(entry->lsk);
kfree(entry);
}
kfree(w);
}

static void mptcp_pm_free_addr_entry(struct mptcp_pm_addr_entry *entry)
{
struct addr_entry_release_work *w;

w = kmalloc(sizeof(*w), GFP_ATOMIC);
if (w) {
INIT_RCU_WORK(&w->rwork, mptcp_pm_release_addr_entry);
w->entry = entry;
queue_rcu_work(system_wq, &w->rwork);
}
}

static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info)
{
struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
Expand Down Expand Up @@ -1011,7 +1103,7 @@ static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info)
spin_unlock_bh(&pernet->lock);

mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), &entry->addr);
kfree_rcu(entry, rcu);
mptcp_pm_free_addr_entry(entry);

return ret;
}
Expand All @@ -1025,7 +1117,7 @@ static void __flush_addrs(struct net *net, struct list_head *list)
struct mptcp_pm_addr_entry, list);
mptcp_nl_remove_subflow_and_signal_addr(net, &cur->addr);
list_del_rcu(&cur->list);
kfree_rcu(cur, rcu);
mptcp_pm_free_addr_entry(cur);
}
}

Expand Down
2 changes: 1 addition & 1 deletion net/mptcp/protocol.c
Original file line number Diff line number Diff line change
Expand Up @@ -52,7 +52,7 @@ static struct net_device mptcp_napi_dev;
* completed yet or has failed, return the subflow socket.
* Otherwise return NULL.
*/
static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk)
{
if (!msk->subflow || READ_ONCE(msk->can_ack))
return NULL;
Expand Down
4 changes: 4 additions & 0 deletions net/mptcp/protocol.h
Original file line number Diff line number Diff line change
Expand Up @@ -538,11 +538,15 @@ void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
struct mptcp_subflow_context *subflow);
void mptcp_subflow_reset(struct sock *ssk);
void mptcp_sock_graft(struct sock *sk, struct socket *parent);
struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk);

/* called with sk socket lock held */
int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
const struct mptcp_addr_info *remote);
int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
struct sockaddr_storage *addr,
unsigned short family);

static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
struct mptcp_subflow_context *ctx)
Expand Down
6 changes: 3 additions & 3 deletions net/mptcp/subflow.c
Original file line number Diff line number Diff line change
Expand Up @@ -1084,9 +1084,9 @@ void mptcpv6_handle_mapped(struct sock *sk, bool mapped)
}
#endif

static void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
struct sockaddr_storage *addr,
unsigned short family)
void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
struct sockaddr_storage *addr,
unsigned short family)
{
memset(addr, 0, sizeof(*addr));
addr->ss_family = family;
Expand Down

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