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yaml
---
r: 369322
b: refs/heads/master
c: 5fd9612
h: refs/heads/master
v: v3
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Patrick McHardy authored and David S. Miller committed Apr 19, 2013
1 parent a8be405 commit 2cfef3a
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Showing 2 changed files with 130 additions and 7 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 9652e931e73be7e54a9c40e9bcd4bbdafe92a406
refs/heads/master: 5fd96123ee19b96be7d7b57fd42227e1a146ef05
135 changes: 129 additions & 6 deletions trunk/net/netlink/af_netlink.c
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Original file line number Diff line number Diff line change
Expand Up @@ -116,6 +116,11 @@ static bool netlink_skb_is_mmaped(const struct sk_buff *skb)
return NETLINK_CB(skb).flags & NETLINK_SKB_MMAPED;
}

static bool netlink_tx_is_mmaped(struct sock *sk)
{
return nlk_sk(sk)->tx_ring.pg_vec != NULL;
}

static __pure struct page *pgvec_to_page(const void *addr)
{
if (is_vmalloc_addr(addr))
Expand Down Expand Up @@ -438,6 +443,9 @@ static unsigned int netlink_poll(struct file *file, struct socket *sock,
struct netlink_sock *nlk = nlk_sk(sk);
unsigned int mask;

if (nlk->cb != NULL && nlk->rx_ring.pg_vec != NULL)
netlink_dump(sk);

mask = datagram_poll(file, sock, wait);

spin_lock_bh(&sk->sk_receive_queue.lock);
Expand Down Expand Up @@ -483,10 +491,110 @@ static void netlink_ring_setup_skb(struct sk_buff *skb, struct sock *sk,
NETLINK_CB(skb).flags |= NETLINK_SKB_MMAPED;
NETLINK_CB(skb).sk = sk;
}

static int netlink_mmap_sendmsg(struct sock *sk, struct msghdr *msg,
u32 dst_portid, u32 dst_group,
struct sock_iocb *siocb)
{
struct netlink_sock *nlk = nlk_sk(sk);
struct netlink_ring *ring;
struct nl_mmap_hdr *hdr;
struct sk_buff *skb;
unsigned int maxlen;
bool excl = true;
int err = 0, len = 0;

/* Netlink messages are validated by the receiver before processing.
* In order to avoid userspace changing the contents of the message
* after validation, the socket and the ring may only be used by a
* single process, otherwise we fall back to copying.
*/
if (atomic_long_read(&sk->sk_socket->file->f_count) > 2 ||
atomic_read(&nlk->mapped) > 1)
excl = false;

mutex_lock(&nlk->pg_vec_lock);

ring = &nlk->tx_ring;
maxlen = ring->frame_size - NL_MMAP_HDRLEN;

do {
hdr = netlink_current_frame(ring, NL_MMAP_STATUS_VALID);
if (hdr == NULL) {
if (!(msg->msg_flags & MSG_DONTWAIT) &&
atomic_read(&nlk->tx_ring.pending))
schedule();
continue;
}
if (hdr->nm_len > maxlen) {
err = -EINVAL;
goto out;
}

netlink_frame_flush_dcache(hdr);

if (likely(dst_portid == 0 && dst_group == 0 && excl)) {
skb = alloc_skb_head(GFP_KERNEL);
if (skb == NULL) {
err = -ENOBUFS;
goto out;
}
sock_hold(sk);
netlink_ring_setup_skb(skb, sk, ring, hdr);
NETLINK_CB(skb).flags |= NETLINK_SKB_TX;
__skb_put(skb, hdr->nm_len);
netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
atomic_inc(&ring->pending);
} else {
skb = alloc_skb(hdr->nm_len, GFP_KERNEL);
if (skb == NULL) {
err = -ENOBUFS;
goto out;
}
__skb_put(skb, hdr->nm_len);
memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, hdr->nm_len);
netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
}

netlink_increment_head(ring);

NETLINK_CB(skb).portid = nlk->portid;
NETLINK_CB(skb).dst_group = dst_group;
NETLINK_CB(skb).creds = siocb->scm->creds;

err = security_netlink_send(sk, skb);
if (err) {
kfree_skb(skb);
goto out;
}

if (unlikely(dst_group)) {
atomic_inc(&skb->users);
netlink_broadcast(sk, skb, dst_portid, dst_group,
GFP_KERNEL);
}
err = netlink_unicast(sk, skb, dst_portid,
msg->msg_flags & MSG_DONTWAIT);
if (err < 0)
goto out;
len += err;

} while (hdr != NULL ||
(!(msg->msg_flags & MSG_DONTWAIT) &&
atomic_read(&nlk->tx_ring.pending)));

if (len > 0)
err = len;
out:
mutex_unlock(&nlk->pg_vec_lock);
return err;
}
#else /* CONFIG_NETLINK_MMAP */
#define netlink_skb_is_mmaped(skb) false
#define netlink_tx_is_mmaped(sk) false
#define netlink_mmap sock_no_mmap
#define netlink_poll datagram_poll
#define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, siocb) 0
#endif /* CONFIG_NETLINK_MMAP */

static void netlink_destroy_callback(struct netlink_callback *cb)
Expand Down Expand Up @@ -517,11 +625,16 @@ static void netlink_skb_destructor(struct sk_buff *skb)
hdr = netlink_mmap_hdr(skb);
sk = NETLINK_CB(skb).sk;

if (!(NETLINK_CB(skb).flags & NETLINK_SKB_DELIVERED)) {
hdr->nm_len = 0;
netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
if (NETLINK_CB(skb).flags & NETLINK_SKB_TX) {
netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
ring = &nlk_sk(sk)->tx_ring;
} else {
if (!(NETLINK_CB(skb).flags & NETLINK_SKB_DELIVERED)) {
hdr->nm_len = 0;
netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
}
ring = &nlk_sk(sk)->rx_ring;
}
ring = &nlk_sk(sk)->rx_ring;

WARN_ON(atomic_read(&ring->pending) == 0);
atomic_dec(&ring->pending);
Expand Down Expand Up @@ -1230,8 +1343,9 @@ int netlink_attachskb(struct sock *sk, struct sk_buff *skb,

nlk = nlk_sk(sk);

if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
test_bit(NETLINK_CONGESTED, &nlk->state)) {
if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
test_bit(NETLINK_CONGESTED, &nlk->state)) &&
!netlink_skb_is_mmaped(skb)) {
DECLARE_WAITQUEUE(wait, current);
if (!*timeo) {
if (!ssk || netlink_is_kernel(ssk))
Expand Down Expand Up @@ -1291,6 +1405,8 @@ static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
int delta;

WARN_ON(skb->sk != NULL);
if (netlink_skb_is_mmaped(skb))
return skb;

delta = skb->end - skb->tail;
if (delta * 2 < skb->truesize)
Expand Down Expand Up @@ -1815,6 +1931,13 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
goto out;
}

if (netlink_tx_is_mmaped(sk) &&
msg->msg_iov->iov_base == NULL) {
err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
siocb);
goto out;
}

err = -EMSGSIZE;
if (len > sk->sk_sndbuf - 32)
goto out;
Expand Down

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