diff options
Diffstat (limited to 'net/mctp/route.c')
| -rw-r--r-- | net/mctp/route.c | 1432 |
1 files changed, 1432 insertions, 0 deletions
diff --git a/net/mctp/route.c b/net/mctp/route.c new file mode 100644 index 000000000..68be8f2b6 --- /dev/null +++ b/net/mctp/route.c @@ -0,0 +1,1432 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Management Component Transport Protocol (MCTP) - routing + * implementation. + * + * This is currently based on a simple routing table, with no dst cache. The + * number of routes should stay fairly small, so the lookup cost is small. + * + * Copyright (c) 2021 Code Construct + * Copyright (c) 2021 Google + */ + +#include <linux/idr.h> +#include <linux/kconfig.h> +#include <linux/mctp.h> +#include <linux/netdevice.h> +#include <linux/rtnetlink.h> +#include <linux/skbuff.h> + +#include <uapi/linux/if_arp.h> + +#include <net/mctp.h> +#include <net/mctpdevice.h> +#include <net/netlink.h> +#include <net/sock.h> + +#include <trace/events/mctp.h> + +static const unsigned int mctp_message_maxlen = 64 * 1024; +static const unsigned long mctp_key_lifetime = 6 * CONFIG_HZ; + +static void mctp_flow_prepare_output(struct sk_buff *skb, struct mctp_dev *dev); + +/* route output callbacks */ +static int mctp_route_discard(struct mctp_route *route, struct sk_buff *skb) +{ + kfree_skb(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 (!mctp_address_matches(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 (!mctp_address_matches(key->local_addr, local)) + return false; + + if (key->peer_addr != peer) + return false; + + if (key->tag != tag) + return false; + + return true; +} + +/* returns a key (with key->lock held, and refcounted), or NULL if no such + * key exists. + */ +static struct mctp_sk_key *mctp_lookup_key(struct net *net, struct sk_buff *skb, + mctp_eid_t peer, + unsigned long *irqflags) + __acquires(&key->lock) +{ + struct mctp_sk_key *key, *ret; + unsigned long flags; + struct mctp_hdr *mh; + u8 tag; + + mh = mctp_hdr(skb); + tag = mh->flags_seq_tag & (MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO); + + ret = NULL; + spin_lock_irqsave(&net->mctp.keys_lock, flags); + + hlist_for_each_entry(key, &net->mctp.keys, hlist) { + if (!mctp_key_match(key, mh->dest, peer, tag)) + continue; + + spin_lock(&key->lock); + if (key->valid) { + refcount_inc(&key->refs); + ret = key; + break; + } + spin_unlock(&key->lock); + } + + if (ret) { + spin_unlock(&net->mctp.keys_lock); + *irqflags = flags; + } else { + spin_unlock_irqrestore(&net->mctp.keys_lock, flags); + } + + 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; + key->valid = true; + spin_lock_init(&key->lock); + refcount_set(&key->refs, 1); + sock_hold(key->sk); + + return key; +} + +void mctp_key_unref(struct mctp_sk_key *key) +{ + unsigned long flags; + + if (!refcount_dec_and_test(&key->refs)) + return; + + /* even though no refs exist here, the lock allows us to stay + * consistent with the locking requirement of mctp_dev_release_key + */ + spin_lock_irqsave(&key->lock, flags); + mctp_dev_release_key(key->dev, key); + spin_unlock_irqrestore(&key->lock, flags); + + sock_put(key->sk); + kfree(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); + + if (sock_flag(&msk->sk, SOCK_DEAD)) { + rc = -EINVAL; + goto out_unlock; + } + + hlist_for_each_entry(tmp, &net->mctp.keys, hlist) { + if (mctp_key_match(tmp, key->local_addr, key->peer_addr, + key->tag)) { + spin_lock(&tmp->lock); + if (tmp->valid) + rc = -EEXIST; + spin_unlock(&tmp->lock); + if (rc) + break; + } + } + + if (!rc) { + refcount_inc(&key->refs); + key->expiry = jiffies + mctp_key_lifetime; + timer_reduce(&msk->key_expiry, key->expiry); + + hlist_add_head(&key->hlist, &net->mctp.keys); + hlist_add_head(&key->sklist, &msk->keys); + } + +out_unlock: + spin_unlock_irqrestore(&net->mctp.keys_lock, flags); + + return rc; +} + +/* 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_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; + + if (!key->manual_alloc) { + key->reasm_dead = true; + key->valid = false; + mctp_dev_release_key(key->dev, key); + } + spin_unlock_irqrestore(&key->lock, flags); + + if (!key->manual_alloc) { + spin_lock_irqsave(&net->mctp.keys_lock, flags); + if (!hlist_unhashed(&key->hlist)) { + hlist_del_init(&key->hlist); + hlist_del_init(&key->sklist); + mctp_key_unref(key); + } + spin_unlock_irqrestore(&net->mctp.keys_lock, flags); + } + + /* and one for the local reference */ + mctp_key_unref(key); + + kfree_skb(skb); +} + +#ifdef CONFIG_MCTP_FLOWS +static void mctp_skb_set_flow(struct sk_buff *skb, struct mctp_sk_key *key) +{ + struct mctp_flow *flow; + + flow = skb_ext_add(skb, SKB_EXT_MCTP); + if (!flow) + return; + + refcount_inc(&key->refs); + flow->key = key; +} + +static void mctp_flow_prepare_output(struct sk_buff *skb, struct mctp_dev *dev) +{ + struct mctp_sk_key *key; + struct mctp_flow *flow; + + flow = skb_ext_find(skb, SKB_EXT_MCTP); + if (!flow) + return; + + key = flow->key; + + if (WARN_ON(key->dev && key->dev != dev)) + return; + + mctp_dev_set_key(dev, key); +} +#else +static void mctp_skb_set_flow(struct sk_buff *skb, struct mctp_sk_key *key) {} +static void mctp_flow_prepare_output(struct sk_buff *skb, struct mctp_dev *dev) {} +#endif + +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 mctp_sk_key *key, *any_key = NULL; + struct net *net = dev_net(skb->dev); + 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 + */ + skb_orphan(skb); + + /* ensure we have enough data for a header and a type */ + if (skb->len < sizeof(struct mctp_hdr) + 1) + goto out; + + /* grab header, advance data ptr */ + mh = mctp_hdr(skb); + skb_pull(skb, sizeof(struct mctp_hdr)); + + if (mh->ver != 1) + goto out; + + 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(); + + /* lookup socket / reasm context, exactly matching (src,dest,tag). + * we hold a ref on the key, and key->lock held. + */ + key = mctp_lookup_key(net, skb, mh->src, &f); + + 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). + */ + any_key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY, &f); + if (any_key) { + msk = container_of(any_key->sk, + struct mctp_sock, sk); + spin_unlock_irqrestore(&any_key->lock, f); + } + } + + if (!key && !msk && (tag & MCTP_HDR_FLAG_TO)) + msk = mctp_lookup_bind(net, skb); + + if (!msk) { + rc = -ENOENT; + goto out_unlock; + } + + /* 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) { + /* we've hit a pending reassembly; not much we + * can do but drop it + */ + __mctp_key_done_in(key, net, f, + MCTP_TRACE_KEY_REPLIED); + key = NULL; + } + rc = 0; + goto out_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; + } + + /* we can queue without the key 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) + trace_mctp_key_acquire(key); + + /* we don't need to release key->lock on exit, so + * clean up here and suppress the unlock via + * setting to NULL + */ + mctp_key_unref(key); + key = NULL; + + } else { + if (key->reasm_head || key->reasm_dead) { + /* duplicate start? drop everything */ + __mctp_key_done_in(key, net, f, + MCTP_TRACE_KEY_INVALIDATED); + rc = -EEXIST; + key = NULL; + } else { + rc = mctp_frag_queue(key, skb); + } + } + + } else if (key) { + /* this packet continues a previous message; reassemble + * using the message-specific key + */ + + /* 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_done_in(key, net, f, MCTP_TRACE_KEY_REPLIED); + key = NULL; + } + + } else { + /* not a start, no matching key */ + rc = -ENOENT; + } + +out_unlock: + rcu_read_unlock(); + if (key) { + spin_unlock_irqrestore(&key->lock, f); + mctp_key_unref(key); + } + if (any_key) + mctp_key_unref(any_key); +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) +{ + struct mctp_skb_cb *cb = mctp_cb(skb); + struct mctp_hdr *hdr = mctp_hdr(skb); + char daddr_buf[MAX_ADDR_LEN]; + char *daddr = NULL; + unsigned int mtu; + int rc; + + skb->protocol = htons(ETH_P_MCTP); + + mtu = READ_ONCE(skb->dev->mtu); + if (skb->len > mtu) { + kfree_skb(skb); + return -EMSGSIZE; + } + + if (cb->ifindex) { + /* direct route; use the hwaddr we stashed in sendmsg */ + if (cb->halen != skb->dev->addr_len) { + /* sanity check, sendmsg should have already caught this */ + kfree_skb(skb); + return -EMSGSIZE; + } + daddr = cb->haddr; + } else { + /* If lookup fails let the device handle daddr==NULL */ + if (mctp_neigh_lookup(route->dev, hdr->dest, daddr_buf) == 0) + daddr = daddr_buf; + } + + rc = dev_hard_header(skb, skb->dev, ntohs(skb->protocol), + daddr, skb->dev->dev_addr, skb->len); + if (rc < 0) { + kfree_skb(skb); + return -EHOSTUNREACH; + } + + mctp_flow_prepare_output(skb, route->dev); + + rc = dev_queue_xmit(skb); + if (rc) + rc = net_xmit_errno(rc); + + return rc; +} + +/* route alloc/release */ +static void mctp_route_release(struct mctp_route *rt) +{ + if (refcount_dec_and_test(&rt->refs)) { + mctp_dev_put(rt->dev); + kfree_rcu(rt, rcu); + } +} + +/* returns a route with the refcount at 1 */ +static struct mctp_route *mctp_route_alloc(void) +{ + struct mctp_route *rt; + + rt = kzalloc(sizeof(*rt), GFP_KERNEL); + if (!rt) + return NULL; + + INIT_LIST_HEAD(&rt->list); + refcount_set(&rt->refs, 1); + rt->output = mctp_route_discard; + + return rt; +} + +unsigned int mctp_default_net(struct net *net) +{ + return READ_ONCE(net->mctp.default_net); +} + +int mctp_default_net_set(struct net *net, unsigned int index) +{ + if (index == 0) + return -EINVAL; + WRITE_ONCE(net->mctp.default_net, index); + return 0; +} + +/* 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->expiry = jiffies + mctp_key_lifetime; + timer_reduce(&msk->key_expiry, key->expiry); + + /* 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); + refcount_inc(&key->refs); +} + +/* Allocate a locally-owned tag value for (saddr, daddr), and reserve + * it for the socket msk + */ +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; + struct mctp_sk_key *key, *tmp; + unsigned long flags; + u8 tagbits; + + /* for NULL destination EIDs, we may get a response from any peer */ + if (daddr == MCTP_ADDR_NULL) + daddr = MCTP_ADDR_ANY; + + /* be optimistic, alloc now */ + key = mctp_key_alloc(msk, saddr, daddr, 0, GFP_KERNEL); + if (!key) + return ERR_PTR(-ENOMEM); + + /* 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) { + /* We can check the lookup fields (*_addr, tag) without the + * lock held, they don't change over the lifetime of the key. + */ + + /* if we don't own the tag, it can't conflict */ + if (tmp->tag & MCTP_HDR_FLAG_TO) + continue; + + if (!(mctp_address_matches(tmp->peer_addr, daddr) && + mctp_address_matches(tmp->local_addr, saddr))) + continue; + + spin_lock(&tmp->lock); + /* key must still be valid. If we find a match, clear the + * potential tag value + */ + if (tmp->valid) + tagbits &= ~(1 << tmp->tag); + spin_unlock(&tmp->lock); + + if (!tagbits) + break; + } + + if (tagbits) { + key->tag = __ffs(tagbits); + mctp_reserve_tag(net, key, msk); + trace_mctp_key_acquire(key); + + key->manual_alloc = manual; + *tagp = key->tag; + } + + spin_unlock_irqrestore(&mns->keys_lock, flags); + + if (!tagbits) { + kfree(key); + return ERR_PTR(-EBUSY); + } + + 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) +{ + return READ_ONCE(rt->dev->net) == net && + rt->min <= eid && rt->max >= eid; +} + +/* compares match, used for duplicate prevention */ +static bool mctp_rt_compare_exact(struct mctp_route *rt1, + struct mctp_route *rt2) +{ + ASSERT_RTNL(); + return rt1->dev->net == rt2->dev->net && + rt1->min == rt2->min && + rt1->max == rt2->max; +} + +struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet, + mctp_eid_t daddr) +{ + struct mctp_route *tmp, *rt = NULL; + + rcu_read_lock(); + + list_for_each_entry_rcu(tmp, &net->mctp.routes, list) { + /* TODO: add metrics */ + if (mctp_rt_match_eid(tmp, dnet, daddr)) { + if (refcount_inc_not_zero(&tmp->refs)) { + rt = tmp; + break; + } + } + } + + rcu_read_unlock(); + + return rt; +} + +static struct mctp_route *mctp_route_lookup_null(struct net *net, + struct net_device *dev) +{ + struct mctp_route *tmp, *rt = NULL; + + rcu_read_lock(); + + list_for_each_entry_rcu(tmp, &net->mctp.routes, list) { + if (tmp->dev->dev == dev && tmp->type == RTN_LOCAL && + refcount_inc_not_zero(&tmp->refs)) { + rt = tmp; + break; + } + } + + rcu_read_unlock(); + + return rt; +} + +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, headroom; + 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; + } + + /* keep same headroom as the original skb */ + headroom = skb_headroom(skb); + + /* 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(headroom + 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, headroom); + 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 */ + rc = rt->output(rt, skb2); + if (rc) + break; + + seq = (seq + 1) & MCTP_HDR_SEQ_MASK; + pos += size; + } + + 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_sock *msk = container_of(sk, struct mctp_sock, sk); + struct mctp_skb_cb *cb = mctp_cb(skb); + struct mctp_route tmp_rt = {0}; + struct mctp_sk_key *key; + struct mctp_hdr *hdr; + unsigned long flags; + unsigned int mtu; + mctp_eid_t saddr; + bool ext_rt; + int rc; + u8 tag; + + rc = -ENODEV; + + if (rt) { + ext_rt = false; + if (WARN_ON(!rt->dev)) + goto out_release; + + } else if (cb->ifindex) { + struct net_device *dev; + + ext_rt = true; + rt = &tmp_rt; + + rcu_read_lock(); + dev = dev_get_by_index_rcu(sock_net(sk), cb->ifindex); + if (!dev) { + rcu_read_unlock(); + return rc; + } + rt->dev = __mctp_dev_get(dev); + rcu_read_unlock(); + + if (!rt->dev) + goto out_release; + + /* establish temporary route - we set up enough to keep + * mctp_route_output happy + */ + rt->output = mctp_route_output; + rt->mtu = 0; + + } else { + return -EINVAL; + } + + spin_lock_irqsave(&rt->dev->addrs_lock, flags); + if (rt->dev->num_addrs == 0) { + rc = -EHOSTUNREACH; + } else { + /* use the outbound interface's first address as our source */ + saddr = rt->dev->addrs[0]; + rc = 0; + } + spin_unlock_irqrestore(&rt->dev->addrs_lock, flags); + + if (rc) + goto out_release; + + 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; + } + mctp_skb_set_flow(skb, key); + /* done with the key in this scope */ + mctp_key_unref(key); + tag |= MCTP_HDR_FLAG_TO; + } else { + key = NULL; + tag = req_tag & MCTP_TAG_MASK; + } + + 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; + + mtu = mctp_route_mtu(rt); + + if (skb->len + sizeof(struct mctp_hdr) <= mtu) { + hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM | + MCTP_HDR_FLAG_EOM | tag; + rc = rt->output(rt, skb); + } else { + rc = mctp_do_fragment_route(rt, skb, mtu, tag); + } + +out_release: + if (!ext_rt) + mctp_route_release(rt); + + mctp_dev_put(tmp_rt.dev); + + return rc; +} + +/* route management */ +static int mctp_route_add(struct mctp_dev *mdev, mctp_eid_t daddr_start, + unsigned int daddr_extent, unsigned int mtu, + unsigned char type) +{ + int (*rtfn)(struct mctp_route *rt, struct sk_buff *skb); + struct net *net = dev_net(mdev->dev); + struct mctp_route *rt, *ert; + + if (!mctp_address_unicast(daddr_start)) + return -EINVAL; + + if (daddr_extent > 0xff || daddr_start + daddr_extent >= 255) + return -EINVAL; + + switch (type) { + case RTN_LOCAL: + rtfn = mctp_route_input; + break; + case RTN_UNICAST: + rtfn = mctp_route_output; + break; + default: + return -EINVAL; + } + + rt = mctp_route_alloc(); + if (!rt) + return -ENOMEM; + + rt->min = daddr_start; + rt->max = daddr_start + daddr_extent; + rt->mtu = mtu; + rt->dev = mdev; + mctp_dev_hold(rt->dev); + rt->type = type; + rt->output = rtfn; + + ASSERT_RTNL(); + /* Prevent duplicate identical routes. */ + list_for_each_entry(ert, &net->mctp.routes, list) { + if (mctp_rt_compare_exact(rt, ert)) { + mctp_route_release(rt); + return -EEXIST; + } + } + + list_add_rcu(&rt->list, &net->mctp.routes); + + return 0; +} + +static int mctp_route_remove(struct mctp_dev *mdev, mctp_eid_t daddr_start, + unsigned int daddr_extent, unsigned char type) +{ + struct net *net = dev_net(mdev->dev); + struct mctp_route *rt, *tmp; + mctp_eid_t daddr_end; + bool dropped; + + if (daddr_extent > 0xff || daddr_start + daddr_extent >= 255) + return -EINVAL; + + daddr_end = daddr_start + daddr_extent; + dropped = false; + + ASSERT_RTNL(); + + list_for_each_entry_safe(rt, tmp, &net->mctp.routes, list) { + if (rt->dev == mdev && + rt->min == daddr_start && rt->max == daddr_end && + rt->type == type) { + list_del_rcu(&rt->list); + /* TODO: immediate RTM_DELROUTE */ + mctp_route_release(rt); + dropped = true; + } + } + + return dropped ? 0 : -ENOENT; +} + +int mctp_route_add_local(struct mctp_dev *mdev, mctp_eid_t addr) +{ + return mctp_route_add(mdev, addr, 0, 0, RTN_LOCAL); +} + +int mctp_route_remove_local(struct mctp_dev *mdev, mctp_eid_t addr) +{ + return mctp_route_remove(mdev, addr, 0, RTN_LOCAL); +} + +/* removes all entries for a given device */ +void mctp_route_remove_dev(struct mctp_dev *mdev) +{ + struct net *net = dev_net(mdev->dev); + struct mctp_route *rt, *tmp; + + ASSERT_RTNL(); + list_for_each_entry_safe(rt, tmp, &net->mctp.routes, list) { + if (rt->dev == mdev) { + list_del_rcu(&rt->list); + /* TODO: immediate RTM_DELROUTE */ + mctp_route_release(rt); + } + } +} + +/* Incoming packet-handling */ + +static int mctp_pkttype_receive(struct sk_buff *skb, struct net_device *dev, + struct packet_type *pt, + struct net_device *orig_dev) +{ + struct net *net = dev_net(dev); + struct mctp_dev *mdev; + struct mctp_skb_cb *cb; + struct mctp_route *rt; + struct mctp_hdr *mh; + + rcu_read_lock(); + mdev = __mctp_dev_get(dev); + rcu_read_unlock(); + if (!mdev) { + /* basic non-data sanity checks */ + goto err_drop; + } + + if (!pskb_may_pull(skb, sizeof(struct mctp_hdr))) + goto err_drop; + + skb_reset_transport_header(skb); + skb_reset_network_header(skb); + + /* We have enough for a header; decode and route */ + mh = mctp_hdr(skb); + if (mh->ver < MCTP_VER_MIN || mh->ver > MCTP_VER_MAX) + goto err_drop; + + /* source must be valid unicast or null; drop reserved ranges and + * broadcast + */ + if (!(mctp_address_unicast(mh->src) || mctp_address_null(mh->src))) + goto err_drop; + + /* dest address: as above, but allow broadcast */ + if (!(mctp_address_unicast(mh->dest) || mctp_address_null(mh->dest) || + mctp_address_broadcast(mh->dest))) + goto err_drop; + + /* MCTP drivers must populate halen/haddr */ + if (dev->type == ARPHRD_MCTP) { + cb = mctp_cb(skb); + } else { + cb = __mctp_cb(skb); + cb->halen = 0; + } + cb->net = READ_ONCE(mdev->net); + cb->ifindex = dev->ifindex; + + rt = mctp_route_lookup(net, cb->net, mh->dest); + + /* NULL EID, but addressed to our physical address */ + if (!rt && mh->dest == MCTP_ADDR_NULL && skb->pkt_type == PACKET_HOST) + rt = mctp_route_lookup_null(net, dev); + + if (!rt) + goto err_drop; + + rt->output(rt, skb); + mctp_route_release(rt); + mctp_dev_put(mdev); + + return NET_RX_SUCCESS; + +err_drop: + kfree_skb(skb); + mctp_dev_put(mdev); + return NET_RX_DROP; +} + +static struct packet_type mctp_packet_type = { + .type = cpu_to_be16(ETH_P_MCTP), + .func = mctp_pkttype_receive, +}; + +/* netlink interface */ + +static const struct nla_policy rta_mctp_policy[RTA_MAX + 1] = { + [RTA_DST] = { .type = NLA_U8 }, + [RTA_METRICS] = { .type = NLA_NESTED }, + [RTA_OIF] = { .type = NLA_U32 }, +}; + +/* Common part for RTM_NEWROUTE and RTM_DELROUTE parsing. + * tb must hold RTA_MAX+1 elements. + */ +static int mctp_route_nlparse(struct sk_buff *skb, struct nlmsghdr *nlh, + struct netlink_ext_ack *extack, + struct nlattr **tb, struct rtmsg **rtm, + struct mctp_dev **mdev, mctp_eid_t *daddr_start) +{ + struct net *net = sock_net(skb->sk); + struct net_device *dev; + unsigned int ifindex; + int rc; + + rc = nlmsg_parse(nlh, sizeof(struct rtmsg), tb, RTA_MAX, + rta_mctp_policy, extack); + if (rc < 0) { + NL_SET_ERR_MSG(extack, "incorrect format"); + return rc; + } + + if (!tb[RTA_DST]) { + NL_SET_ERR_MSG(extack, "dst EID missing"); + return -EINVAL; + } + *daddr_start = nla_get_u8(tb[RTA_DST]); + + if (!tb[RTA_OIF]) { + NL_SET_ERR_MSG(extack, "ifindex missing"); + return -EINVAL; + } + ifindex = nla_get_u32(tb[RTA_OIF]); + + *rtm = nlmsg_data(nlh); + if ((*rtm)->rtm_family != AF_MCTP) { + NL_SET_ERR_MSG(extack, "route family must be AF_MCTP"); + return -EINVAL; + } + + dev = __dev_get_by_index(net, ifindex); + if (!dev) { + NL_SET_ERR_MSG(extack, "bad ifindex"); + return -ENODEV; + } + *mdev = mctp_dev_get_rtnl(dev); + if (!*mdev) + return -ENODEV; + + if (dev->flags & IFF_LOOPBACK) { + NL_SET_ERR_MSG(extack, "no routes to loopback"); + return -EINVAL; + } + + return 0; +} + +static const struct nla_policy rta_metrics_policy[RTAX_MAX + 1] = { + [RTAX_MTU] = { .type = NLA_U32 }, +}; + +static int mctp_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, + struct netlink_ext_ack *extack) +{ + struct nlattr *tb[RTA_MAX + 1]; + struct nlattr *tbx[RTAX_MAX + 1]; + mctp_eid_t daddr_start; + struct mctp_dev *mdev; + struct rtmsg *rtm; + unsigned int mtu; + int rc; + + rc = mctp_route_nlparse(skb, nlh, extack, tb, + &rtm, &mdev, &daddr_start); + if (rc < 0) + return rc; + + if (rtm->rtm_type != RTN_UNICAST) { + NL_SET_ERR_MSG(extack, "rtm_type must be RTN_UNICAST"); + return -EINVAL; + } + + mtu = 0; + if (tb[RTA_METRICS]) { + rc = nla_parse_nested(tbx, RTAX_MAX, tb[RTA_METRICS], + rta_metrics_policy, NULL); + if (rc < 0) + return rc; + if (tbx[RTAX_MTU]) + mtu = nla_get_u32(tbx[RTAX_MTU]); + } + + if (rtm->rtm_type != RTN_UNICAST) + return -EINVAL; + + rc = mctp_route_add(mdev, daddr_start, rtm->rtm_dst_len, mtu, + rtm->rtm_type); + return rc; +} + +static int mctp_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, + struct netlink_ext_ack *extack) +{ + struct nlattr *tb[RTA_MAX + 1]; + mctp_eid_t daddr_start; + struct mctp_dev *mdev; + struct rtmsg *rtm; + int rc; + + rc = mctp_route_nlparse(skb, nlh, extack, tb, + &rtm, &mdev, &daddr_start); + if (rc < 0) + return rc; + + /* we only have unicast routes */ + if (rtm->rtm_type != RTN_UNICAST) + return -EINVAL; + + rc = mctp_route_remove(mdev, daddr_start, rtm->rtm_dst_len, RTN_UNICAST); + return rc; +} + +static int mctp_fill_rtinfo(struct sk_buff *skb, struct mctp_route *rt, + u32 portid, u32 seq, int event, unsigned int flags) +{ + struct nlmsghdr *nlh; + struct rtmsg *hdr; + void *metrics; + + nlh = nlmsg_put(skb, portid, seq, event, sizeof(*hdr), flags); + if (!nlh) + return -EMSGSIZE; + + hdr = nlmsg_data(nlh); + hdr->rtm_family = AF_MCTP; + + /* we use the _len fields as a number of EIDs, rather than + * a number of bits in the address + */ + hdr->rtm_dst_len = rt->max - rt->min; + hdr->rtm_src_len = 0; + hdr->rtm_tos = 0; + hdr->rtm_table = RT_TABLE_DEFAULT; + hdr->rtm_protocol = RTPROT_STATIC; /* everything is user-defined */ + hdr->rtm_scope = RT_SCOPE_LINK; /* TODO: scope in mctp_route? */ + hdr->rtm_type = rt->type; + + if (nla_put_u8(skb, RTA_DST, rt->min)) + goto cancel; + + metrics = nla_nest_start_noflag(skb, RTA_METRICS); + if (!metrics) + goto cancel; + + if (rt->mtu) { + if (nla_put_u32(skb, RTAX_MTU, rt->mtu)) + goto cancel; + } + + nla_nest_end(skb, metrics); + + if (rt->dev) { + if (nla_put_u32(skb, RTA_OIF, rt->dev->dev->ifindex)) + goto cancel; + } + + /* TODO: conditional neighbour physaddr? */ + + nlmsg_end(skb, nlh); + + return 0; + +cancel: + nlmsg_cancel(skb, nlh); + return -EMSGSIZE; +} + +static int mctp_dump_rtinfo(struct sk_buff *skb, struct netlink_callback *cb) +{ + struct net *net = sock_net(skb->sk); + struct mctp_route *rt; + int s_idx, idx; + + /* TODO: allow filtering on route data, possibly under + * cb->strict_check + */ + + /* TODO: change to struct overlay */ + s_idx = cb->args[0]; + idx = 0; + + rcu_read_lock(); + list_for_each_entry_rcu(rt, &net->mctp.routes, list) { + if (idx++ < s_idx) + continue; + if (mctp_fill_rtinfo(skb, rt, + NETLINK_CB(cb->skb).portid, + cb->nlh->nlmsg_seq, + RTM_NEWROUTE, NLM_F_MULTI) < 0) + break; + } + + rcu_read_unlock(); + cb->args[0] = idx; + + return skb->len; +} + +/* net namespace implementation */ +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); + WARN_ON(mctp_default_net_set(net, MCTP_INITIAL_DEFAULT_NET)); + return 0; +} + +static void __net_exit mctp_routes_net_exit(struct net *net) +{ + struct mctp_route *rt; + + rcu_read_lock(); + list_for_each_entry_rcu(rt, &net->mctp.routes, list) + mctp_route_release(rt); + rcu_read_unlock(); +} + +static struct pernet_operations mctp_net_ops = { + .init = mctp_routes_net_init, + .exit = mctp_routes_net_exit, +}; + +int __init mctp_routes_init(void) +{ + dev_add_pack(&mctp_packet_type); + + rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_GETROUTE, + NULL, mctp_dump_rtinfo, 0); + rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_NEWROUTE, + mctp_newroute, NULL, 0); + rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_DELROUTE, + mctp_delroute, NULL, 0); + + return register_pernet_subsys(&mctp_net_ops); +} + +void mctp_routes_exit(void) +{ + unregister_pernet_subsys(&mctp_net_ops); + rtnl_unregister(PF_MCTP, RTM_DELROUTE); + rtnl_unregister(PF_MCTP, RTM_NEWROUTE); + rtnl_unregister(PF_MCTP, RTM_GETROUTE); + dev_remove_pack(&mctp_packet_type); +} + +#if IS_ENABLED(CONFIG_MCTP_TEST) +#include "test/route-test.c" +#endif |