mctp: Populate socket implementation
Start filling-out the socket syscalls: bind, sendmsg & recvmsg.
This requires an input route implementation, so we add to
mctp_route_input, allowing lookups on binds & message tags. This just
handles single-packet messages at present, we will add fragmentation in
a future change.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mctp/route.c b/net/mctp/route.c
index 3156820..cc989167 100644
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -30,10 +30,139 @@ static int mctp_route_discard(struct mctp_route *route, struct sk_buff *skb)
return 0;
}
+static struct mctp_sock *mctp_lookup_bind(struct net *net, struct sk_buff *skb)
+{
+ struct mctp_skb_cb *cb = mctp_cb(skb);
+ struct mctp_hdr *mh;
+ struct sock *sk;
+ u8 type;
+
+ WARN_ON(!rcu_read_lock_held());
+
+ /* TODO: look up in skb->cb? */
+ mh = mctp_hdr(skb);
+
+ if (!skb_headlen(skb))
+ return NULL;
+
+ type = (*(u8 *)skb->data) & 0x7f;
+
+ sk_for_each_rcu(sk, &net->mctp.binds) {
+ struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
+
+ if (msk->bind_net != MCTP_NET_ANY && msk->bind_net != cb->net)
+ continue;
+
+ if (msk->bind_type != type)
+ continue;
+
+ if (msk->bind_addr != MCTP_ADDR_ANY &&
+ msk->bind_addr != mh->dest)
+ continue;
+
+ return msk;
+ }
+
+ return NULL;
+}
+
+static bool mctp_key_match(struct mctp_sk_key *key, mctp_eid_t local,
+ mctp_eid_t peer, u8 tag)
+{
+ if (key->local_addr != local)
+ return false;
+
+ if (key->peer_addr != peer)
+ return false;
+
+ if (key->tag != tag)
+ return false;
+
+ return true;
+}
+
+static struct mctp_sk_key *mctp_lookup_key(struct net *net, struct sk_buff *skb,
+ mctp_eid_t peer)
+{
+ struct mctp_sk_key *key, *ret;
+ struct mctp_hdr *mh;
+ u8 tag;
+
+ WARN_ON(!rcu_read_lock_held());
+
+ mh = mctp_hdr(skb);
+ tag = mh->flags_seq_tag & (MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);
+
+ ret = NULL;
+
+ hlist_for_each_entry_rcu(key, &net->mctp.keys, hlist) {
+ if (mctp_key_match(key, mh->dest, peer, tag)) {
+ ret = key;
+ break;
+ }
+ }
+
+ return ret;
+}
+
static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
{
- /* -> to local stack */
- /* TODO: socket lookup, reassemble */
+ struct net *net = dev_net(skb->dev);
+ struct mctp_sk_key *key;
+ struct mctp_sock *msk;
+ struct mctp_hdr *mh;
+
+ msk = NULL;
+
+ /* we may be receiving a locally-routed packet; drop source sk
+ * accounting
+ */
+ skb_orphan(skb);
+
+ /* ensure we have enough data for a header and a type */
+ if (skb->len < sizeof(struct mctp_hdr) + 1)
+ goto drop;
+
+ /* grab header, advance data ptr */
+ mh = mctp_hdr(skb);
+ skb_pull(skb, sizeof(struct mctp_hdr));
+
+ if (mh->ver != 1)
+ goto drop;
+
+ /* TODO: reassembly */
+ if ((mh->flags_seq_tag & (MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM))
+ != (MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM))
+ goto drop;
+
+ rcu_read_lock();
+ /* 1. lookup socket matching (src,dest,tag) */
+ key = mctp_lookup_key(net, skb, mh->src);
+
+ /* 2. lookup socket macthing (BCAST,dest,tag) */
+ if (!key)
+ key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY);
+
+ /* 3. SOM? -> lookup bound socket, conditionally (!EOM) create
+ * mapping for future (1)/(2).
+ */
+ if (key)
+ msk = container_of(key->sk, struct mctp_sock, sk);
+ else if (!msk && (mh->flags_seq_tag & MCTP_HDR_FLAG_SOM))
+ msk = mctp_lookup_bind(net, skb);
+
+ if (!msk)
+ goto unlock_drop;
+
+ sock_queue_rcv_skb(&msk->sk, skb);
+
+ rcu_read_unlock();
+
+ return 0;
+
+unlock_drop:
+ rcu_read_unlock();
+drop:
kfree_skb(skb);
return 0;
}
@@ -91,6 +220,80 @@ static struct mctp_route *mctp_route_alloc(void)
return rt;
}
+/* tag management */
+static void mctp_reserve_tag(struct net *net, struct mctp_sk_key *key,
+ struct mctp_sock *msk)
+{
+ struct netns_mctp *mns = &net->mctp;
+
+ lockdep_assert_held(&mns->keys_lock);
+
+ key->sk = &msk->sk;
+
+ /* we hold the net->key_lock here, allowing updates to both
+ * then net and sk
+ */
+ hlist_add_head_rcu(&key->hlist, &mns->keys);
+ hlist_add_head_rcu(&key->sklist, &msk->keys);
+}
+
+/* Allocate a locally-owned tag value for (saddr, daddr), and reserve
+ * it for the socket msk
+ */
+static int mctp_alloc_local_tag(struct mctp_sock *msk,
+ mctp_eid_t saddr, mctp_eid_t daddr, u8 *tagp)
+{
+ struct net *net = sock_net(&msk->sk);
+ struct netns_mctp *mns = &net->mctp;
+ struct mctp_sk_key *key, *tmp;
+ unsigned long flags;
+ int rc = -EAGAIN;
+ u8 tagbits;
+
+ /* be optimistic, alloc now */
+ key = kzalloc(sizeof(*key), GFP_KERNEL);
+ if (!key)
+ return -ENOMEM;
+ key->local_addr = saddr;
+ key->peer_addr = daddr;
+
+ /* 8 possible tag values */
+ tagbits = 0xff;
+
+ spin_lock_irqsave(&mns->keys_lock, flags);
+
+ /* Walk through the existing keys, looking for potential conflicting
+ * tags. If we find a conflict, clear that bit from tagbits
+ */
+ hlist_for_each_entry(tmp, &mns->keys, hlist) {
+ /* if we don't own the tag, it can't conflict */
+ if (tmp->tag & MCTP_HDR_FLAG_TO)
+ continue;
+
+ if ((tmp->peer_addr == daddr ||
+ tmp->peer_addr == MCTP_ADDR_ANY) &&
+ tmp->local_addr == saddr)
+ tagbits &= ~(1 << tmp->tag);
+
+ if (!tagbits)
+ break;
+ }
+
+ if (tagbits) {
+ key->tag = __ffs(tagbits);
+ mctp_reserve_tag(net, key, msk);
+ *tagp = key->tag;
+ rc = 0;
+ }
+
+ spin_unlock_irqrestore(&mns->keys_lock, flags);
+
+ if (!tagbits)
+ kfree(key);
+
+ return rc;
+}
+
/* routing lookups */
static bool mctp_rt_match_eid(struct mctp_route *rt,
unsigned int net, mctp_eid_t eid)
@@ -140,11 +343,13 @@ int mctp_do_route(struct mctp_route *rt, struct sk_buff *skb)
int mctp_local_output(struct sock *sk, struct mctp_route *rt,
struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag)
{
+ struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
struct mctp_skb_cb *cb = mctp_cb(skb);
struct mctp_hdr *hdr;
unsigned long flags;
mctp_eid_t saddr;
int rc;
+ u8 tag;
if (WARN_ON(!rt->dev))
return -EINVAL;
@@ -162,6 +367,15 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
if (rc)
return rc;
+ if (req_tag & MCTP_HDR_FLAG_TO) {
+ rc = mctp_alloc_local_tag(msk, saddr, daddr, &tag);
+ if (rc)
+ return rc;
+ tag |= MCTP_HDR_FLAG_TO;
+ } else {
+ tag = req_tag;
+ }
+
/* TODO: we have the route MTU here; packetise */
skb_reset_transport_header(skb);
@@ -171,8 +385,10 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
hdr->ver = 1;
hdr->dest = daddr;
hdr->src = saddr;
- hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM; /* TODO */
+ hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM | /* TODO */
+ tag;
+ skb->dev = rt->dev->dev;
skb->protocol = htons(ETH_P_MCTP);
skb->priority = 0;
@@ -529,6 +745,10 @@ static int __net_init mctp_routes_net_init(struct net *net)
struct netns_mctp *ns = &net->mctp;
INIT_LIST_HEAD(&ns->routes);
+ INIT_HLIST_HEAD(&ns->binds);
+ mutex_init(&ns->bind_lock);
+ INIT_HLIST_HEAD(&ns->keys);
+ spin_lock_init(&ns->keys_lock);
return 0;
}