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route.c
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// 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);
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);
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);
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);
}
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 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
*/
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).
*/
key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY, &f);
if (key) {
msk = container_of(key->sk,
struct mctp_sock, sk);
spin_unlock_irqrestore(&key->lock, f);
mctp_key_unref(key);
key = NULL;
}
}
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) {
kfree(key);
} else {
trace_mctp_key_acquire(key);
/* we don't need to release key->lock on exit */
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);
}
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;
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;
}
}
}
return rt;
}
static struct mctp_route *mctp_route_lookup_null(struct net *net,
struct net_device *dev)
{
struct mctp_route *rt;
list_for_each_entry_rcu(rt, &net->mctp.routes, list) {
if (rt->dev->dev == dev && rt->type == RTN_LOCAL &&
refcount_inc_not_zero(&rt->refs))
return rt;
}
return NULL;
}
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) {