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mctp: Add SIOCMCTP{ALLOC,DROP}TAG ioctls for tag control

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This change adds a couple of new ioctls for mctp sockets:
SIOCMCTPALLOCTAG and SIOCMCTPDROPTAG.  These ioctls provide facilities
for explicit allocation / release of tags, overriding the automatic
allocate-on-send/release-on-reply and timeout behaviours. This allows
userspace more control over messages that may not fit a simple
request/response model.

In order to indicate a pre-allocated tag to the sendmsg() syscall, we
introduce a new flag to the struct sockaddr_mctp.smctp_tag value:
MCTP_TAG_PREALLOC.

Additional changes from Jeremy Kerr <jk@codeconstruct.com.au>.

Contains a fix that was:
Reported-by: kernel test robot <lkp@intel.com>

Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Matt Johnston
2022-02-09 12:05:57 +08:00
committed by David S. Miller
parent 0de55a7d11
commit 63ed1aab3d
6 changed files with 329 additions and 56 deletions
Download Patch File Download Diff File Expand all files Collapse all files

114
net/mctp/route.c
View File

@@ -203,29 +203,38 @@ static int mctp_key_add(struct mctp_sk_key *key, struct mctp_sock *msk)
return rc;
}
/* We're done with the key; unset valid and remove from lists. There may still
* be outstanding refs on the key though...
/* Helper for mctp_route_input().
* We're done with the key; unlock and unref the key.
* For the usual case of automatic expiry we remove the key from lists.
* In the case that manual allocation is set on a key we release the lock
* and local ref, reset reassembly, but don't remove from lists.
*/
static void __mctp_key_unlock_drop(struct mctp_sk_key *key, struct net *net,
unsigned long flags)
__releases(&key->lock)
static void __mctp_key_done_in(struct mctp_sk_key *key, struct net *net,
unsigned long flags, unsigned long reason)
__releases(&key->lock)
{
struct sk_buff *skb;
trace_mctp_key_release(key, reason);
skb = key->reasm_head;
key->reasm_head = NULL;
key->reasm_dead = true;
key->valid = false;
mctp_dev_release_key(key->dev, key);
if (!key->manual_alloc) {
key->reasm_dead = true;
key->valid = false;
mctp_dev_release_key(key->dev, key);
}
spin_unlock_irqrestore(&key->lock, flags);
spin_lock_irqsave(&net->mctp.keys_lock, flags);
hlist_del(&key->hlist);
hlist_del(&key->sklist);
spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
if (!key->manual_alloc) {
spin_lock_irqsave(&net->mctp.keys_lock, flags);
hlist_del(&key->hlist);
hlist_del(&key->sklist);
spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
/* one unref for the lists */
mctp_key_unref(key);
/* unref for the lists */
mctp_key_unref(key);
}
/* and one for the local reference */
mctp_key_unref(key);
@@ -379,9 +388,8 @@ static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
/* we've hit a pending reassembly; not much we
* can do but drop it
*/
trace_mctp_key_release(key,
MCTP_TRACE_KEY_REPLIED);
__mctp_key_unlock_drop(key, net, f);
__mctp_key_done_in(key, net, f,
MCTP_TRACE_KEY_REPLIED);
key = NULL;
}
rc = 0;
@@ -423,9 +431,8 @@ static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
} else {
if (key->reasm_head || key->reasm_dead) {
/* duplicate start? drop everything */
trace_mctp_key_release(key,
MCTP_TRACE_KEY_INVALIDATED);
__mctp_key_unlock_drop(key, net, f);
__mctp_key_done_in(key, net, f,
MCTP_TRACE_KEY_INVALIDATED);
rc = -EEXIST;
key = NULL;
} else {
@@ -448,10 +455,10 @@ static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
* the reassembly/response key
*/
if (!rc && flags & MCTP_HDR_FLAG_EOM) {
msk = container_of(key->sk, struct mctp_sock, sk);
sock_queue_rcv_skb(key->sk, key->reasm_head);
key->reasm_head = NULL;
trace_mctp_key_release(key, MCTP_TRACE_KEY_REPLIED);
__mctp_key_unlock_drop(key, net, f);
__mctp_key_done_in(key, net, f, MCTP_TRACE_KEY_REPLIED);
key = NULL;
}
@@ -579,9 +586,9 @@ static void mctp_reserve_tag(struct net *net, struct mctp_sk_key *key,
/* Allocate a locally-owned tag value for (saddr, daddr), and reserve
* it for the socket msk
*/
static struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
mctp_eid_t saddr,
mctp_eid_t daddr, u8 *tagp)
struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
mctp_eid_t daddr, mctp_eid_t saddr,
bool manual, u8 *tagp)
{
struct net *net = sock_net(&msk->sk);
struct netns_mctp *mns = &net->mctp;
@@ -636,6 +643,7 @@ static struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
mctp_reserve_tag(net, key, msk);
trace_mctp_key_acquire(key);
key->manual_alloc = manual;
*tagp = key->tag;
}
@@ -649,6 +657,50 @@ static struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
return key;
}
static struct mctp_sk_key *mctp_lookup_prealloc_tag(struct mctp_sock *msk,
mctp_eid_t daddr,
u8 req_tag, u8 *tagp)
{
struct net *net = sock_net(&msk->sk);
struct netns_mctp *mns = &net->mctp;
struct mctp_sk_key *key, *tmp;
unsigned long flags;
req_tag &= ~(MCTP_TAG_PREALLOC | MCTP_TAG_OWNER);
key = NULL;
spin_lock_irqsave(&mns->keys_lock, flags);
hlist_for_each_entry(tmp, &mns->keys, hlist) {
if (tmp->tag != req_tag)
continue;
if (!mctp_address_matches(tmp->peer_addr, daddr))
continue;
if (!tmp->manual_alloc)
continue;
spin_lock(&tmp->lock);
if (tmp->valid) {
key = tmp;
refcount_inc(&key->refs);
spin_unlock(&tmp->lock);
break;
}
spin_unlock(&tmp->lock);
}
spin_unlock_irqrestore(&mns->keys_lock, flags);
if (!key)
return ERR_PTR(-ENOENT);
if (tagp)
*tagp = key->tag;
return key;
}
/* routing lookups */
static bool mctp_rt_match_eid(struct mctp_route *rt,
unsigned int net, mctp_eid_t eid)
@@ -843,8 +895,14 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
if (rc)
goto out_release;
if (req_tag & MCTP_HDR_FLAG_TO) {
key = mctp_alloc_local_tag(msk, saddr, daddr, &tag);
if (req_tag & MCTP_TAG_OWNER) {
if (req_tag & MCTP_TAG_PREALLOC)
key = mctp_lookup_prealloc_tag(msk, daddr,
req_tag, &tag);
else
key = mctp_alloc_local_tag(msk, daddr, saddr,
false, &tag);
if (IS_ERR(key)) {
rc = PTR_ERR(key);
goto out_release;
@@ -855,7 +913,7 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
tag |= MCTP_HDR_FLAG_TO;
} else {
key = NULL;
tag = req_tag;
tag = req_tag & MCTP_TAG_MASK;
}
skb->protocol = htons(ETH_P_MCTP);