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author | Jeremy Kerr <jk@codeconstruct.com.au> | 2021-07-29 10:20:49 +0800 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2021-07-29 15:06:50 +0100 |
commit | 833ef3b91de692ef33b800bca6b1569c39dece74 (patch) | |
tree | ff450c69b1a4b9c9d8ff83d832e870461c546f69 /net/mctp/route.c | |
parent | 831119f8878173adbf31f1151adf0f4627c05e01 (diff) | |
download | linux-833ef3b91de692ef33b800bca6b1569c39dece74.tar.gz linux-833ef3b91de692ef33b800bca6b1569c39dece74.tar.bz2 linux-833ef3b91de692ef33b800bca6b1569c39dece74.zip |
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>
Diffstat (limited to 'net/mctp/route.c')
-rw-r--r-- | net/mctp/route.c | 226 |
1 files changed, 223 insertions, 3 deletions
diff --git a/net/mctp/route.c b/net/mctp/route.c index 31568203f9d0..cc9891672eaa 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; } |