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Florian Westphaldavem330
Florian Westphal
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davem330
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mptcp: netlink: allow userspace-driven subflow establishment
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 <[email protected]> Co-developed-by: Kishen Maloor <[email protected]> Signed-off-by: Kishen Maloor <[email protected]> Signed-off-by: Florian Westphal <[email protected]> Signed-off-by: Mat Martineau <[email protected]> Signed-off-by: David S. Miller <[email protected]>
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‎include/uapi/linux/mptcp.h

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -57,6 +57,7 @@ enum {
5757
MPTCP_PM_ATTR_SUBFLOWS, /* u32 */
5858
MPTCP_PM_ATTR_TOKEN, /* u32 */
5959
MPTCP_PM_ATTR_LOC_ID, /* u8 */
60+
MPTCP_PM_ATTR_ADDR_REMOTE, /* nested address */
6061

6162
__MPTCP_PM_ATTR_MAX
6263
};
@@ -97,6 +98,8 @@ enum {
9798
MPTCP_PM_CMD_SET_FLAGS,
9899
MPTCP_PM_CMD_ANNOUNCE,
99100
MPTCP_PM_CMD_REMOVE,
101+
MPTCP_PM_CMD_SUBFLOW_CREATE,
102+
MPTCP_PM_CMD_SUBFLOW_DESTROY,
100103

101104
__MPTCP_PM_CMD_AFTER_LAST
102105
};

‎net/mptcp/pm_netlink.c

Lines changed: 22 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1096,6 +1096,8 @@ static const struct nla_policy mptcp_pm_policy[MPTCP_PM_ATTR_MAX + 1] = {
10961096
[MPTCP_PM_ATTR_SUBFLOWS] = { .type = NLA_U32, },
10971097
[MPTCP_PM_ATTR_TOKEN] = { .type = NLA_U32, },
10981098
[MPTCP_PM_ATTR_LOC_ID] = { .type = NLA_U8, },
1099+
[MPTCP_PM_ATTR_ADDR_REMOTE] =
1100+
NLA_POLICY_NESTED(mptcp_pm_addr_policy),
10991101
};
11001102

11011103
void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk)
@@ -1205,6 +1207,16 @@ static int mptcp_pm_parse_pm_addr_attr(struct nlattr *tb[],
12051207
return err;
12061208
}
12071209

1210+
int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
1211+
struct mptcp_addr_info *addr)
1212+
{
1213+
struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
1214+
1215+
memset(addr, 0, sizeof(*addr));
1216+
1217+
return mptcp_pm_parse_pm_addr_attr(tb, attr, info, addr, true);
1218+
}
1219+
12081220
int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
12091221
bool require_family,
12101222
struct mptcp_pm_addr_entry *entry)
@@ -2210,6 +2222,16 @@ static const struct genl_small_ops mptcp_pm_ops[] = {
22102222
.doit = mptcp_nl_cmd_remove,
22112223
.flags = GENL_ADMIN_PERM,
22122224
},
2225+
{
2226+
.cmd = MPTCP_PM_CMD_SUBFLOW_CREATE,
2227+
.doit = mptcp_nl_cmd_sf_create,
2228+
.flags = GENL_ADMIN_PERM,
2229+
},
2230+
{
2231+
.cmd = MPTCP_PM_CMD_SUBFLOW_DESTROY,
2232+
.doit = mptcp_nl_cmd_sf_destroy,
2233+
.flags = GENL_ADMIN_PERM,
2234+
},
22132235
};
22142236

22152237
static struct genl_family mptcp_genl_family __ro_after_init = {

‎net/mptcp/pm_userspace.c

Lines changed: 185 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -242,3 +242,188 @@ int mptcp_nl_cmd_remove(struct sk_buff *skb, struct genl_info *info)
242242
sock_put((struct sock *)msk);
243243
return err;
244244
}
245+
246+
int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info)
247+
{
248+
struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
249+
struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
250+
struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
251+
struct mptcp_addr_info addr_r;
252+
struct mptcp_addr_info addr_l;
253+
struct mptcp_sock *msk;
254+
int err = -EINVAL;
255+
struct sock *sk;
256+
u32 token_val;
257+
258+
if (!laddr || !raddr || !token) {
259+
GENL_SET_ERR_MSG(info, "missing required inputs");
260+
return err;
261+
}
262+
263+
token_val = nla_get_u32(token);
264+
265+
msk = mptcp_token_get_sock(genl_info_net(info), token_val);
266+
if (!msk) {
267+
NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
268+
return err;
269+
}
270+
271+
if (!mptcp_pm_is_userspace(msk)) {
272+
GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
273+
goto create_err;
274+
}
275+
276+
err = mptcp_pm_parse_addr(laddr, info, &addr_l);
277+
if (err < 0) {
278+
NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr");
279+
goto create_err;
280+
}
281+
282+
if (addr_l.id == 0) {
283+
NL_SET_ERR_MSG_ATTR(info->extack, laddr, "missing local addr id");
284+
goto create_err;
285+
}
286+
287+
err = mptcp_pm_parse_addr(raddr, info, &addr_r);
288+
if (err < 0) {
289+
NL_SET_ERR_MSG_ATTR(info->extack, raddr, "error parsing remote addr");
290+
goto create_err;
291+
}
292+
293+
sk = &msk->sk.icsk_inet.sk;
294+
lock_sock(sk);
295+
296+
err = __mptcp_subflow_connect(sk, &addr_l, &addr_r);
297+
298+
release_sock(sk);
299+
300+
create_err:
301+
sock_put((struct sock *)msk);
302+
return err;
303+
}
304+
305+
static struct sock *mptcp_nl_find_ssk(struct mptcp_sock *msk,
306+
const struct mptcp_addr_info *local,
307+
const struct mptcp_addr_info *remote)
308+
{
309+
struct sock *sk = &msk->sk.icsk_inet.sk;
310+
struct mptcp_subflow_context *subflow;
311+
struct sock *found = NULL;
312+
313+
if (local->family != remote->family)
314+
return NULL;
315+
316+
lock_sock(sk);
317+
318+
mptcp_for_each_subflow(msk, subflow) {
319+
const struct inet_sock *issk;
320+
struct sock *ssk;
321+
322+
ssk = mptcp_subflow_tcp_sock(subflow);
323+
324+
if (local->family != ssk->sk_family)
325+
continue;
326+
327+
issk = inet_sk(ssk);
328+
329+
switch (ssk->sk_family) {
330+
case AF_INET:
331+
if (issk->inet_saddr != local->addr.s_addr ||
332+
issk->inet_daddr != remote->addr.s_addr)
333+
continue;
334+
break;
335+
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
336+
case AF_INET6: {
337+
const struct ipv6_pinfo *pinfo = inet6_sk(ssk);
338+
339+
if (!ipv6_addr_equal(&local->addr6, &pinfo->saddr) ||
340+
!ipv6_addr_equal(&remote->addr6, &ssk->sk_v6_daddr))
341+
continue;
342+
break;
343+
}
344+
#endif
345+
default:
346+
continue;
347+
}
348+
349+
if (issk->inet_sport == local->port &&
350+
issk->inet_dport == remote->port) {
351+
found = ssk;
352+
goto found;
353+
}
354+
}
355+
356+
found:
357+
release_sock(sk);
358+
359+
return found;
360+
}
361+
362+
int mptcp_nl_cmd_sf_destroy(struct sk_buff *skb, struct genl_info *info)
363+
{
364+
struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
365+
struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
366+
struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
367+
struct mptcp_addr_info addr_l;
368+
struct mptcp_addr_info addr_r;
369+
struct mptcp_sock *msk;
370+
struct sock *sk, *ssk;
371+
int err = -EINVAL;
372+
u32 token_val;
373+
374+
if (!laddr || !raddr || !token) {
375+
GENL_SET_ERR_MSG(info, "missing required inputs");
376+
return err;
377+
}
378+
379+
token_val = nla_get_u32(token);
380+
381+
msk = mptcp_token_get_sock(genl_info_net(info), token_val);
382+
if (!msk) {
383+
NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
384+
return err;
385+
}
386+
387+
if (!mptcp_pm_is_userspace(msk)) {
388+
GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
389+
goto destroy_err;
390+
}
391+
392+
err = mptcp_pm_parse_addr(laddr, info, &addr_l);
393+
if (err < 0) {
394+
NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr");
395+
goto destroy_err;
396+
}
397+
398+
err = mptcp_pm_parse_addr(raddr, info, &addr_r);
399+
if (err < 0) {
400+
NL_SET_ERR_MSG_ATTR(info->extack, raddr, "error parsing remote addr");
401+
goto destroy_err;
402+
}
403+
404+
if (addr_l.family != addr_r.family) {
405+
GENL_SET_ERR_MSG(info, "address families do not match");
406+
goto destroy_err;
407+
}
408+
409+
if (!addr_l.port || !addr_r.port) {
410+
GENL_SET_ERR_MSG(info, "missing local or remote port");
411+
goto destroy_err;
412+
}
413+
414+
sk = &msk->sk.icsk_inet.sk;
415+
ssk = mptcp_nl_find_ssk(msk, &addr_l, &addr_r);
416+
if (ssk) {
417+
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
418+
419+
mptcp_subflow_shutdown(sk, ssk, RCV_SHUTDOWN | SEND_SHUTDOWN);
420+
mptcp_close_ssk(sk, ssk, subflow);
421+
err = 0;
422+
} else {
423+
err = -ESRCH;
424+
}
425+
426+
destroy_err:
427+
sock_put((struct sock *)msk);
428+
return err;
429+
}

‎net/mptcp/protocol.h

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -756,6 +756,8 @@ u16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum);
756756
void __init mptcp_pm_init(void);
757757
void mptcp_pm_data_init(struct mptcp_sock *msk);
758758
void mptcp_pm_data_reset(struct mptcp_sock *msk);
759+
int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
760+
struct mptcp_addr_info *addr);
759761
int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
760762
bool require_family,
761763
struct mptcp_pm_addr_entry *entry);
@@ -809,6 +811,8 @@ int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
809811
void mptcp_free_local_addr_list(struct mptcp_sock *msk);
810812
int mptcp_nl_cmd_announce(struct sk_buff *skb, struct genl_info *info);
811813
int mptcp_nl_cmd_remove(struct sk_buff *skb, struct genl_info *info);
814+
int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info);
815+
int mptcp_nl_cmd_sf_destroy(struct sk_buff *skb, struct genl_info *info);
812816

813817
void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
814818
const struct sock *ssk, gfp_t gfp);

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