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>
This commit is contained in:
Jeremy Kerr
committed by
David S. Miller
David S. Miller
parent
831119f887
commit
833ef3b91d
226
net/mctp/route.c
226
net/mctp/route.c
@@ -30,10 +30,139 @@ static int mctp_route_discard(struct mctp_route *route, struct sk_buff *skb)
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return 0;
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}
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static struct mctp_sock *mctp_lookup_bind(struct net *net, struct sk_buff *skb)
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{
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struct mctp_skb_cb *cb = mctp_cb(skb);
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struct mctp_hdr *mh;
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struct sock *sk;
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u8 type;
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WARN_ON(!rcu_read_lock_held());
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/* TODO: look up in skb->cb? */
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mh = mctp_hdr(skb);
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if (!skb_headlen(skb))
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return NULL;
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type = (*(u8 *)skb->data) & 0x7f;
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sk_for_each_rcu(sk, &net->mctp.binds) {
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struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
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if (msk->bind_net != MCTP_NET_ANY && msk->bind_net != cb->net)
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continue;
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if (msk->bind_type != type)
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continue;
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if (msk->bind_addr != MCTP_ADDR_ANY &&
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msk->bind_addr != mh->dest)
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continue;
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return msk;
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}
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return NULL;
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}
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static bool mctp_key_match(struct mctp_sk_key *key, mctp_eid_t local,
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mctp_eid_t peer, u8 tag)
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{
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if (key->local_addr != local)
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return false;
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if (key->peer_addr != peer)
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return false;
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if (key->tag != tag)
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return false;
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return true;
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}
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static struct mctp_sk_key *mctp_lookup_key(struct net *net, struct sk_buff *skb,
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mctp_eid_t peer)
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{
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struct mctp_sk_key *key, *ret;
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struct mctp_hdr *mh;
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u8 tag;
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WARN_ON(!rcu_read_lock_held());
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mh = mctp_hdr(skb);
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tag = mh->flags_seq_tag & (MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);
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ret = NULL;
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hlist_for_each_entry_rcu(key, &net->mctp.keys, hlist) {
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if (mctp_key_match(key, mh->dest, peer, tag)) {
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ret = key;
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break;
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}
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}
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return ret;
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}
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static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
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{
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/* -> to local stack */
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/* TODO: socket lookup, reassemble */
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struct net *net = dev_net(skb->dev);
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struct mctp_sk_key *key;
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struct mctp_sock *msk;
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struct mctp_hdr *mh;
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msk = NULL;
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/* we may be receiving a locally-routed packet; drop source sk
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* accounting
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*/
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skb_orphan(skb);
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/* ensure we have enough data for a header and a type */
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if (skb->len < sizeof(struct mctp_hdr) + 1)
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goto drop;
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/* grab header, advance data ptr */
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mh = mctp_hdr(skb);
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skb_pull(skb, sizeof(struct mctp_hdr));
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if (mh->ver != 1)
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goto drop;
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/* TODO: reassembly */
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if ((mh->flags_seq_tag & (MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM))
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!= (MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM))
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goto drop;
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rcu_read_lock();
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/* 1. lookup socket matching (src,dest,tag) */
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key = mctp_lookup_key(net, skb, mh->src);
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/* 2. lookup socket macthing (BCAST,dest,tag) */
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if (!key)
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key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY);
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/* 3. SOM? -> lookup bound socket, conditionally (!EOM) create
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* mapping for future (1)/(2).
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*/
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if (key)
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msk = container_of(key->sk, struct mctp_sock, sk);
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else if (!msk && (mh->flags_seq_tag & MCTP_HDR_FLAG_SOM))
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msk = mctp_lookup_bind(net, skb);
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if (!msk)
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goto unlock_drop;
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sock_queue_rcv_skb(&msk->sk, skb);
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rcu_read_unlock();
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return 0;
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unlock_drop:
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rcu_read_unlock();
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drop:
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kfree_skb(skb);
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return 0;
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}
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@@ -91,6 +220,80 @@ static struct mctp_route *mctp_route_alloc(void)
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return rt;
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}
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/* tag management */
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static void mctp_reserve_tag(struct net *net, struct mctp_sk_key *key,
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struct mctp_sock *msk)
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{
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struct netns_mctp *mns = &net->mctp;
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lockdep_assert_held(&mns->keys_lock);
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key->sk = &msk->sk;
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/* we hold the net->key_lock here, allowing updates to both
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* then net and sk
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*/
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hlist_add_head_rcu(&key->hlist, &mns->keys);
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hlist_add_head_rcu(&key->sklist, &msk->keys);
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}
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/* Allocate a locally-owned tag value for (saddr, daddr), and reserve
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* it for the socket msk
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*/
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static int mctp_alloc_local_tag(struct mctp_sock *msk,
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mctp_eid_t saddr, mctp_eid_t daddr, u8 *tagp)
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{
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struct net *net = sock_net(&msk->sk);
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struct netns_mctp *mns = &net->mctp;
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struct mctp_sk_key *key, *tmp;
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unsigned long flags;
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int rc = -EAGAIN;
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u8 tagbits;
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/* be optimistic, alloc now */
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key = kzalloc(sizeof(*key), GFP_KERNEL);
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if (!key)
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return -ENOMEM;
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key->local_addr = saddr;
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key->peer_addr = daddr;
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/* 8 possible tag values */
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tagbits = 0xff;
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spin_lock_irqsave(&mns->keys_lock, flags);
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/* Walk through the existing keys, looking for potential conflicting
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* tags. If we find a conflict, clear that bit from tagbits
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*/
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hlist_for_each_entry(tmp, &mns->keys, hlist) {
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/* if we don't own the tag, it can't conflict */
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if (tmp->tag & MCTP_HDR_FLAG_TO)
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continue;
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if ((tmp->peer_addr == daddr ||
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tmp->peer_addr == MCTP_ADDR_ANY) &&
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tmp->local_addr == saddr)
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tagbits &= ~(1 << tmp->tag);
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if (!tagbits)
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break;
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}
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if (tagbits) {
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key->tag = __ffs(tagbits);
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mctp_reserve_tag(net, key, msk);
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*tagp = key->tag;
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rc = 0;
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}
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spin_unlock_irqrestore(&mns->keys_lock, flags);
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if (!tagbits)
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kfree(key);
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return rc;
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}
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/* routing lookups */
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static bool mctp_rt_match_eid(struct mctp_route *rt,
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unsigned int net, mctp_eid_t eid)
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@@ -140,11 +343,13 @@ int mctp_do_route(struct mctp_route *rt, struct sk_buff *skb)
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int mctp_local_output(struct sock *sk, struct mctp_route *rt,
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struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag)
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{
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struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
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struct mctp_skb_cb *cb = mctp_cb(skb);
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struct mctp_hdr *hdr;
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unsigned long flags;
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mctp_eid_t saddr;
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int rc;
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u8 tag;
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if (WARN_ON(!rt->dev))
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return -EINVAL;
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@@ -162,6 +367,15 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
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if (rc)
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return rc;
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if (req_tag & MCTP_HDR_FLAG_TO) {
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rc = mctp_alloc_local_tag(msk, saddr, daddr, &tag);
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if (rc)
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return rc;
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tag |= MCTP_HDR_FLAG_TO;
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} else {
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tag = req_tag;
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}
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/* TODO: we have the route MTU here; packetise */
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skb_reset_transport_header(skb);
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@@ -171,8 +385,10 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
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hdr->ver = 1;
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hdr->dest = daddr;
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hdr->src = saddr;
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hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM; /* TODO */
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hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM | /* TODO */
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tag;
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skb->dev = rt->dev->dev;
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skb->protocol = htons(ETH_P_MCTP);
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skb->priority = 0;
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@@ -529,6 +745,10 @@ static int __net_init mctp_routes_net_init(struct net *net)
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struct netns_mctp *ns = &net->mctp;
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INIT_LIST_HEAD(&ns->routes);
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INIT_HLIST_HEAD(&ns->binds);
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mutex_init(&ns->bind_lock);
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INIT_HLIST_HEAD(&ns->keys);
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spin_lock_init(&ns->keys_lock);
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return 0;
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}
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