#include <net/netlink.h>
#include <net/sock.h>
+static const unsigned int mctp_message_maxlen = 64 * 1024;
+
/* route output callbacks */
static int mctp_route_discard(struct mctp_route *route, struct sk_buff *skb)
{
return ret;
}
+static struct mctp_sk_key *mctp_key_alloc(struct mctp_sock *msk,
+ mctp_eid_t local, mctp_eid_t peer,
+ u8 tag, gfp_t gfp)
+{
+ struct mctp_sk_key *key;
+
+ key = kzalloc(sizeof(*key), gfp);
+ if (!key)
+ return NULL;
+
+ key->peer_addr = peer;
+ key->local_addr = local;
+ key->tag = tag;
+ key->sk = &msk->sk;
+ spin_lock_init(&key->reasm_lock);
+
+ return key;
+}
+
+static int mctp_key_add(struct mctp_sk_key *key, struct mctp_sock *msk)
+{
+ struct net *net = sock_net(&msk->sk);
+ struct mctp_sk_key *tmp;
+ unsigned long flags;
+ int rc = 0;
+
+ spin_lock_irqsave(&net->mctp.keys_lock, flags);
+
+ hlist_for_each_entry(tmp, &net->mctp.keys, hlist) {
+ if (mctp_key_match(tmp, key->local_addr, key->peer_addr,
+ key->tag)) {
+ rc = -EEXIST;
+ break;
+ }
+ }
+
+ if (!rc) {
+ hlist_add_head(&key->hlist, &net->mctp.keys);
+ hlist_add_head(&key->sklist, &msk->keys);
+ }
+
+ spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
+
+ return rc;
+}
+
+/* Must be called with key->reasm_lock, which it will release. Will schedule
+ * the key for an RCU free.
+ */
+static void __mctp_key_unlock_drop(struct mctp_sk_key *key, struct net *net,
+ unsigned long flags)
+ __releases(&key->reasm_lock)
+{
+ struct sk_buff *skb;
+
+ skb = key->reasm_head;
+ key->reasm_head = NULL;
+ key->reasm_dead = true;
+ spin_unlock_irqrestore(&key->reasm_lock, flags);
+
+ spin_lock_irqsave(&net->mctp.keys_lock, flags);
+ hlist_del_rcu(&key->hlist);
+ hlist_del_rcu(&key->sklist);
+ spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
+ kfree_rcu(key, rcu);
+
+ if (skb)
+ kfree_skb(skb);
+}
+
+static int mctp_frag_queue(struct mctp_sk_key *key, struct sk_buff *skb)
+{
+ struct mctp_hdr *hdr = mctp_hdr(skb);
+ u8 exp_seq, this_seq;
+
+ this_seq = (hdr->flags_seq_tag >> MCTP_HDR_SEQ_SHIFT)
+ & MCTP_HDR_SEQ_MASK;
+
+ if (!key->reasm_head) {
+ key->reasm_head = skb;
+ key->reasm_tailp = &(skb_shinfo(skb)->frag_list);
+ key->last_seq = this_seq;
+ return 0;
+ }
+
+ exp_seq = (key->last_seq + 1) & MCTP_HDR_SEQ_MASK;
+
+ if (this_seq != exp_seq)
+ return -EINVAL;
+
+ if (key->reasm_head->len + skb->len > mctp_message_maxlen)
+ return -EINVAL;
+
+ skb->next = NULL;
+ skb->sk = NULL;
+ *key->reasm_tailp = skb;
+ key->reasm_tailp = &skb->next;
+
+ key->last_seq = this_seq;
+
+ key->reasm_head->data_len += skb->len;
+ key->reasm_head->len += skb->len;
+ key->reasm_head->truesize += skb->truesize;
+
+ return 0;
+}
+
static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
{
struct net *net = dev_net(skb->dev);
struct mctp_sk_key *key;
struct mctp_sock *msk;
struct mctp_hdr *mh;
+ unsigned long f;
+ u8 tag, flags;
+ int rc;
msk = NULL;
+ rc = -EINVAL;
/* we may be receiving a locally-routed packet; drop source sk
* accounting
/* ensure we have enough data for a header and a type */
if (skb->len < sizeof(struct mctp_hdr) + 1)
- goto drop;
+ goto out;
/* grab header, advance data ptr */
mh = mctp_hdr(skb);
skb_pull(skb, sizeof(struct mctp_hdr));
if (mh->ver != 1)
- goto drop;
+ goto out;
- /* 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;
+ flags = mh->flags_seq_tag & (MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM);
+ tag = mh->flags_seq_tag & (MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);
rcu_read_lock();
- /* 1. lookup socket matching (src,dest,tag) */
+
+ /* lookup socket / reasm context, exactly 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);
+ if (flags & MCTP_HDR_FLAG_SOM) {
+ if (key) {
+ msk = container_of(key->sk, struct mctp_sock, sk);
+ } else {
+ /* first response to a broadcast? do a more general
+ * key lookup to find the socket, but don't use this
+ * key for reassembly - we'll create a more specific
+ * one for future packets if required (ie, !EOM).
+ */
+ key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY);
+ if (key) {
+ msk = container_of(key->sk,
+ struct mctp_sock, sk);
+ key = NULL;
+ }
+ }
- /* 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 (!key && !msk && (tag & MCTP_HDR_FLAG_TO))
+ msk = mctp_lookup_bind(net, skb);
- if (!msk)
- goto unlock_drop;
+ if (!msk) {
+ rc = -ENOENT;
+ goto out_unlock;
+ }
- sock_queue_rcv_skb(&msk->sk, skb);
+ /* single-packet message? deliver to socket, clean up any
+ * pending key.
+ */
+ if (flags & MCTP_HDR_FLAG_EOM) {
+ sock_queue_rcv_skb(&msk->sk, skb);
+ if (key) {
+ spin_lock_irqsave(&key->reasm_lock, f);
+ /* we've hit a pending reassembly; not much we
+ * can do but drop it
+ */
+ __mctp_key_unlock_drop(key, net, f);
+ }
+ rc = 0;
+ goto out_unlock;
+ }
- rcu_read_unlock();
+ /* broadcast response or a bind() - create a key for further
+ * packets for this message
+ */
+ if (!key) {
+ key = mctp_key_alloc(msk, mh->dest, mh->src,
+ tag, GFP_ATOMIC);
+ if (!key) {
+ rc = -ENOMEM;
+ goto out_unlock;
+ }
- return 0;
+ /* we can queue without the reasm lock here, as the
+ * key isn't observable yet
+ */
+ mctp_frag_queue(key, skb);
+
+ /* if the key_add fails, we've raced with another
+ * SOM packet with the same src, dest and tag. There's
+ * no way to distinguish future packets, so all we
+ * can do is drop; we'll free the skb on exit from
+ * this function.
+ */
+ rc = mctp_key_add(key, msk);
+ if (rc)
+ kfree(key);
+
+ } else {
+ /* existing key: start reassembly */
+ spin_lock_irqsave(&key->reasm_lock, f);
+
+ if (key->reasm_head || key->reasm_dead) {
+ /* duplicate start? drop everything */
+ __mctp_key_unlock_drop(key, net, f);
+ rc = -EEXIST;
+ } else {
+ rc = mctp_frag_queue(key, skb);
+ spin_unlock_irqrestore(&key->reasm_lock, f);
+ }
+ }
+
+ } else if (key) {
+ /* this packet continues a previous message; reassemble
+ * using the message-specific key
+ */
+
+ spin_lock_irqsave(&key->reasm_lock, f);
+
+ /* we need to be continuing an existing reassembly... */
+ if (!key->reasm_head)
+ rc = -EINVAL;
+ else
+ rc = mctp_frag_queue(key, skb);
+
+ /* end of message? deliver to socket, and we're done with
+ * the reassembly/response key
+ */
+ if (!rc && flags & MCTP_HDR_FLAG_EOM) {
+ sock_queue_rcv_skb(key->sk, key->reasm_head);
+ key->reasm_head = NULL;
+ __mctp_key_unlock_drop(key, net, f);
+ } else {
+ spin_unlock_irqrestore(&key->reasm_lock, f);
+ }
+
+ } else {
+ /* not a start, no matching key */
+ rc = -ENOENT;
+ }
-unlock_drop:
+out_unlock:
rcu_read_unlock();
-drop:
- kfree_skb(skb);
- return 0;
+out:
+ if (rc)
+ kfree_skb(skb);
+ return rc;
+}
+
+static unsigned int mctp_route_mtu(struct mctp_route *rt)
+{
+ return rt->mtu ?: READ_ONCE(rt->dev->dev->mtu);
}
static int mctp_route_output(struct mctp_route *route, struct sk_buff *skb)
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
*/
u8 tagbits;
/* be optimistic, alloc now */
- key = kzalloc(sizeof(*key), GFP_KERNEL);
+ key = mctp_key_alloc(msk, saddr, daddr, 0, GFP_KERNEL);
if (!key)
return -ENOMEM;
- key->local_addr = saddr;
- key->peer_addr = daddr;
/* 8 possible tag values */
tagbits = 0xff;
return rc;
}
+static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb,
+ unsigned int mtu, u8 tag)
+{
+ const unsigned int hlen = sizeof(struct mctp_hdr);
+ struct mctp_hdr *hdr, *hdr2;
+ unsigned int pos, size;
+ struct sk_buff *skb2;
+ int rc;
+ u8 seq;
+
+ hdr = mctp_hdr(skb);
+ seq = 0;
+ rc = 0;
+
+ if (mtu < hlen + 1) {
+ kfree_skb(skb);
+ return -EMSGSIZE;
+ }
+
+ /* we've got the header */
+ skb_pull(skb, hlen);
+
+ for (pos = 0; pos < skb->len;) {
+ /* size of message payload */
+ size = min(mtu - hlen, skb->len - pos);
+
+ skb2 = alloc_skb(MCTP_HEADER_MAXLEN + hlen + size, GFP_KERNEL);
+ if (!skb2) {
+ rc = -ENOMEM;
+ break;
+ }
+
+ /* generic skb copy */
+ skb2->protocol = skb->protocol;
+ skb2->priority = skb->priority;
+ skb2->dev = skb->dev;
+ memcpy(skb2->cb, skb->cb, sizeof(skb2->cb));
+
+ if (skb->sk)
+ skb_set_owner_w(skb2, skb->sk);
+
+ /* establish packet */
+ skb_reserve(skb2, MCTP_HEADER_MAXLEN);
+ skb_reset_network_header(skb2);
+ skb_put(skb2, hlen + size);
+ skb2->transport_header = skb2->network_header + hlen;
+
+ /* copy header fields, calculate SOM/EOM flags & seq */
+ hdr2 = mctp_hdr(skb2);
+ hdr2->ver = hdr->ver;
+ hdr2->dest = hdr->dest;
+ hdr2->src = hdr->src;
+ hdr2->flags_seq_tag = tag &
+ (MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);
+
+ if (pos == 0)
+ hdr2->flags_seq_tag |= MCTP_HDR_FLAG_SOM;
+
+ if (pos + size == skb->len)
+ hdr2->flags_seq_tag |= MCTP_HDR_FLAG_EOM;
+
+ hdr2->flags_seq_tag |= seq << MCTP_HDR_SEQ_SHIFT;
+
+ /* copy message payload */
+ skb_copy_bits(skb, pos, skb_transport_header(skb2), size);
+
+ /* do route, but don't drop the rt reference */
+ rc = rt->output(rt, skb2);
+ if (rc)
+ break;
+
+ seq = (seq + 1) & MCTP_HDR_SEQ_MASK;
+ pos += size;
+ }
+
+ mctp_route_release(rt);
+ consume_skb(skb);
+ return rc;
+}
+
int mctp_local_output(struct sock *sk, struct mctp_route *rt,
struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag)
{
struct mctp_skb_cb *cb = mctp_cb(skb);
struct mctp_hdr *hdr;
unsigned long flags;
+ unsigned int mtu;
mctp_eid_t saddr;
int rc;
u8 tag;
tag = req_tag;
}
- /* TODO: we have the route MTU here; packetise */
+ skb->protocol = htons(ETH_P_MCTP);
+ skb->priority = 0;
skb_reset_transport_header(skb);
skb_push(skb, sizeof(struct mctp_hdr));
skb_reset_network_header(skb);
+ skb->dev = rt->dev->dev;
+
+ /* cb->net will have been set on initial ingress */
+ cb->src = saddr;
+
+ /* set up common header fields */
hdr = mctp_hdr(skb);
hdr->ver = 1;
hdr->dest = daddr;
hdr->src = saddr;
- 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;
+ mtu = mctp_route_mtu(rt);
- /* cb->net will have been set on initial ingress */
- cb->src = saddr;
-
- return mctp_do_route(rt, skb);
+ if (skb->len + sizeof(struct mctp_hdr) <= mtu) {
+ hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM |
+ tag;
+ return mctp_do_route(rt, skb);
+ } else {
+ return mctp_do_fragment_route(rt, skb, mtu, tag);
+ }
}
/* route management */
projects / users / hch / configfs.git / commitdiff