Skip to content

Commit

Permalink
mptcp: netlink: allow userspace-driven subflow establishment
Browse files Browse the repository at this point in the history 
This allows userspace to tell kernel to add a new subflow to an existing
mptcp connection.

Userspace provides the token to identify the mptcp-level connection
that needs a change in active subflows and the local and remote
addresses of the new or the to-be-removed subflow.

MPTCP_PM_CMD_SUBFLOW_CREATE requires the following parameters:
{ token, { loc_id, family, loc_addr4 | loc_addr6 }, { family, rem_addr4 |
rem_addr6, rem_port }

MPTCP_PM_CMD_SUBFLOW_DESTROY requires the following parameters:
{ token, { family, loc_addr4 | loc_addr6, loc_port }, { family, rem_addr4 |
rem_addr6, rem_port }

Acked-by: Paolo Abeni <pabeni@redhat.com>
Co-developed-by: Kishen Maloor <kishen.maloor@intel.com>
Signed-off-by: Kishen Maloor <kishen.maloor@intel.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
  • Loading branch information
@davem330
Florian Westphal authored and davem330 committed May 4, 2022
1 parent ecd2a77 commit 702c2f6
Show file tree
Hide file tree
Showing 4 changed files with 214 additions and 0 deletions.
3 changes: 3 additions & 0 deletions include/uapi/linux/mptcp.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,7 @@ enum {
MPTCP_PM_ATTR_SUBFLOWS, /* u32 */
MPTCP_PM_ATTR_TOKEN, /* u32 */
MPTCP_PM_ATTR_LOC_ID, /* u8 */
MPTCP_PM_ATTR_ADDR_REMOTE, /* nested address */

__MPTCP_PM_ATTR_MAX
};
Expand Down Expand Up @@ -97,6 +98,8 @@ enum {
MPTCP_PM_CMD_SET_FLAGS,
MPTCP_PM_CMD_ANNOUNCE,
MPTCP_PM_CMD_REMOVE,
MPTCP_PM_CMD_SUBFLOW_CREATE,
MPTCP_PM_CMD_SUBFLOW_DESTROY,

__MPTCP_PM_CMD_AFTER_LAST
};
Expand Down
22 changes: 22 additions & 0 deletions net/mptcp/pm_netlink.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1096,6 +1096,8 @@ static const struct nla_policy mptcp_pm_policy[MPTCP_PM_ATTR_MAX + 1] = {
[MPTCP_PM_ATTR_SUBFLOWS] = { .type = NLA_U32, },
[MPTCP_PM_ATTR_TOKEN] = { .type = NLA_U32, },
[MPTCP_PM_ATTR_LOC_ID] = { .type = NLA_U8, },
[MPTCP_PM_ATTR_ADDR_REMOTE] =
NLA_POLICY_NESTED(mptcp_pm_addr_policy),
};

void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk)
Expand Down Expand Up @@ -1205,6 +1207,16 @@ static int mptcp_pm_parse_pm_addr_attr(struct nlattr *tb[],
return err;
}

int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
struct mptcp_addr_info *addr)
{
struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];

memset(addr, 0, sizeof(*addr));

return mptcp_pm_parse_pm_addr_attr(tb, attr, info, addr, true);
}

int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
bool require_family,
struct mptcp_pm_addr_entry *entry)
Expand Down Expand Up @@ -2210,6 +2222,16 @@ static const struct genl_small_ops mptcp_pm_ops[] = {
.doit = mptcp_nl_cmd_remove,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = MPTCP_PM_CMD_SUBFLOW_CREATE,
.doit = mptcp_nl_cmd_sf_create,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = MPTCP_PM_CMD_SUBFLOW_DESTROY,
.doit = mptcp_nl_cmd_sf_destroy,
.flags = GENL_ADMIN_PERM,
},
};

static struct genl_family mptcp_genl_family __ro_after_init = {
Expand Down
185 changes: 185 additions & 0 deletions net/mptcp/pm_userspace.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -242,3 +242,188 @@ int mptcp_nl_cmd_remove(struct sk_buff *skb, struct genl_info *info)
sock_put((struct sock *)msk);
return err;
}

int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info)
{
struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
struct mptcp_addr_info addr_r;
struct mptcp_addr_info addr_l;
struct mptcp_sock *msk;
int err = -EINVAL;
struct sock *sk;
u32 token_val;

if (!laddr || !raddr || !token) {
GENL_SET_ERR_MSG(info, "missing required inputs");
return err;
}

token_val = nla_get_u32(token);

msk = mptcp_token_get_sock(genl_info_net(info), token_val);
if (!msk) {
NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
return err;
}

if (!mptcp_pm_is_userspace(msk)) {
GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
goto create_err;
}

err = mptcp_pm_parse_addr(laddr, info, &addr_l);
if (err < 0) {
NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr");
goto create_err;
}

if (addr_l.id == 0) {
NL_SET_ERR_MSG_ATTR(info->extack, laddr, "missing local addr id");
goto create_err;
}

err = mptcp_pm_parse_addr(raddr, info, &addr_r);
if (err < 0) {
NL_SET_ERR_MSG_ATTR(info->extack, raddr, "error parsing remote addr");
goto create_err;
}

sk = &msk->sk.icsk_inet.sk;
lock_sock(sk);

err = __mptcp_subflow_connect(sk, &addr_l, &addr_r);

release_sock(sk);

create_err:
sock_put((struct sock *)msk);
return err;
}

static struct sock *mptcp_nl_find_ssk(struct mptcp_sock *msk,
const struct mptcp_addr_info *local,
const struct mptcp_addr_info *remote)
{
struct sock *sk = &msk->sk.icsk_inet.sk;
struct mptcp_subflow_context *subflow;
struct sock *found = NULL;

if (local->family != remote->family)
return NULL;

lock_sock(sk);

mptcp_for_each_subflow(msk, subflow) {
const struct inet_sock *issk;
struct sock *ssk;

ssk = mptcp_subflow_tcp_sock(subflow);

if (local->family != ssk->sk_family)
continue;

issk = inet_sk(ssk);

switch (ssk->sk_family) {
case AF_INET:
if (issk->inet_saddr != local->addr.s_addr ||
issk->inet_daddr != remote->addr.s_addr)
continue;
break;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
case AF_INET6: {
const struct ipv6_pinfo *pinfo = inet6_sk(ssk);

if (!ipv6_addr_equal(&local->addr6, &pinfo->saddr) ||
!ipv6_addr_equal(&remote->addr6, &ssk->sk_v6_daddr))
continue;
break;
}
#endif
default:
continue;
}

if (issk->inet_sport == local->port &&
issk->inet_dport == remote->port) {
found = ssk;
goto found;
}
}

found:
release_sock(sk);

return found;
}

int mptcp_nl_cmd_sf_destroy(struct sk_buff *skb, struct genl_info *info)
{
struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
struct mptcp_addr_info addr_l;
struct mptcp_addr_info addr_r;
struct mptcp_sock *msk;
struct sock *sk, *ssk;
int err = -EINVAL;
u32 token_val;

if (!laddr || !raddr || !token) {
GENL_SET_ERR_MSG(info, "missing required inputs");
return err;
}

token_val = nla_get_u32(token);

msk = mptcp_token_get_sock(genl_info_net(info), token_val);
if (!msk) {
NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
return err;
}

if (!mptcp_pm_is_userspace(msk)) {
GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
goto destroy_err;
}

err = mptcp_pm_parse_addr(laddr, info, &addr_l);
if (err < 0) {
NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr");
goto destroy_err;
}

err = mptcp_pm_parse_addr(raddr, info, &addr_r);
if (err < 0) {
NL_SET_ERR_MSG_ATTR(info->extack, raddr, "error parsing remote addr");
goto destroy_err;
}

if (addr_l.family != addr_r.family) {
GENL_SET_ERR_MSG(info, "address families do not match");
goto destroy_err;
}

if (!addr_l.port || !addr_r.port) {
GENL_SET_ERR_MSG(info, "missing local or remote port");
goto destroy_err;
}

sk = &msk->sk.icsk_inet.sk;
ssk = mptcp_nl_find_ssk(msk, &addr_l, &addr_r);
if (ssk) {
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);

mptcp_subflow_shutdown(sk, ssk, RCV_SHUTDOWN | SEND_SHUTDOWN);
mptcp_close_ssk(sk, ssk, subflow);
err = 0;
} else {
err = -ESRCH;
}

destroy_err:
sock_put((struct sock *)msk);
return err;
}
4 changes: 4 additions & 0 deletions net/mptcp/protocol.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -756,6 +756,8 @@ u16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum);
void __init mptcp_pm_init(void);
void mptcp_pm_data_init(struct mptcp_sock *msk);
void mptcp_pm_data_reset(struct mptcp_sock *msk);
int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
struct mptcp_addr_info *addr);
int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
bool require_family,
struct mptcp_pm_addr_entry *entry);
Expand Down Expand Up @@ -809,6 +811,8 @@ int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
void mptcp_free_local_addr_list(struct mptcp_sock *msk);
int mptcp_nl_cmd_announce(struct sk_buff *skb, struct genl_info *info);
int mptcp_nl_cmd_remove(struct sk_buff *skb, struct genl_info *info);
int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info);
int mptcp_nl_cmd_sf_destroy(struct sk_buff *skb, struct genl_info *info);

void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
const struct sock *ssk, gfp_t gfp);
Expand Down

0 comments on commit 702c2f6

Please sign in to comment.