// 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;
}
/* A note on the key allocations.
*
* struct net->mctp.keys contains our set of currently-allocated keys for
* MCTP tag management. The lookup tuple for these is the peer EID,
* local EID and MCTP tag.
*
* In some cases, the peer EID may be MCTP_EID_ANY: for example, when a
* broadcast message is sent, we may receive responses from any peer EID.
* Because the broadcast dest address is equivalent to ANY, we create
* a key with (local = local-eid, peer = ANY). This allows a match on the
* incoming broadcast responses from any peer.
*
* We perform lookups when packets are received, and when tags are allocated
* in two scenarios:
*
* - when a packet is sent, with a locally-owned tag: we need to find an
* unused tag value for the (local, peer) EID pair.
*
* - when a tag is manually allocated: we need to find an unused tag value
* for the peer EID, but don't have a specific local EID at that stage.
*
* in the latter case, on successful allocation, we end up with a tag with
* (local = ANY, peer = peer-eid).
*
* So, the key set allows both a local EID of ANY, as well as a peer EID of
* ANY in the lookup tuple. Both may be ANY if we prealloc for a broadcast.
* The matching (in mctp_key_match()) during lookup allows the match value to
* be ANY in either the dest or source addresses.
*
* When allocating (+ inserting) a tag, we need to check for conflicts amongst
* the existing tag set. This requires macthing either exactly on the local
* and peer addresses, or either being ANY.
*/
static bool mctp_key_match(struct mctp_sk_key *key, unsigned int net,
mctp_eid_t local, mctp_eid_t peer, u8 tag)
{
if (key->net != net)
return false;
if (!mctp_address_matches(key->local_addr, local))
return false;
if (!mctp_address_matches(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,
unsigned int netid, 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, netid, 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,
unsigned int net,
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->net = net;
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->net, 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 int netid;
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);
netid = mctp_cb(skb)->net;
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, netid, 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).
*
* this lookup requires key->peer to be MCTP_ADDR_ANY,
* it doesn't match just any key->peer.
*/
any_key = mctp_lookup_key(net, skb, netid,
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, netid, 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 (local, peer), and reserve
* it for the socket msk
*/
struct mctp_sk_key *mctp_alloc_local_tag(struct mctp_sock *msk,
unsigned int netid,
mctp_eid_t local, mctp_eid_t peer,
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 (peer == MCTP_ADDR_NULL)
peer = MCTP_ADDR_ANY;
/* be optimistic, alloc now */
key = mctp_key_alloc(msk, netid, local, peer, 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.
*/
/* tags are net-specific */
if (tmp->net != netid)
continue;
/* if we don't own the tag, it can't conflict */
if (tmp->tag & MCTP_HDR_FLAG_TO)
continue;
/* Since we're avoiding conflicting entries, match peer and
* local addresses, including with a wildcard on ANY. See
* 'A note on key allocations' for background.
*/
if (peer != MCTP_ADDR_ANY &&
!mctp_address_matches(tmp->peer_addr, peer))
continue;
if (local != MCTP_ADDR_ANY &&
!mctp_address_matches(tmp->local_addr, local))
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) {
mctp_key_unref(key);
return ERR_PTR(-EBUSY);
}
return key;
}
static struct mctp_sk_key *mctp_lookup_prealloc_tag(struct mctp_sock *msk,
unsigned int netid,
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->net != netid)
continue;
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);
/* we need to copy the extensions, for MCTP flow data */
skb_ext_copy(skb2, skb);
/* 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 netid;
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();
goto out_free;
}
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 {
rc = -EINVAL;
goto out_free;
}
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);
netid = READ_ONCE(rt->dev->net);
if (rc)
goto out_release;
if (req_tag & MCTP_TAG_OWNER) {
if (req_tag & MCTP_TAG_PREALLOC)
key = mctp_lookup_prealloc_tag(msk, netid, daddr,
req_tag, &tag);
else
key = mctp_alloc_local_tag(msk, netid, saddr, daddr,
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);
}
/* route output functions consume the skb, even on error */
skb = NULL;
out_release:
if (!ext_rt)
mctp_route_release(rt);
mctp_dev_put(tmp_rt.dev);
out_free:
kfree_skb(skb);
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]);
}
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
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