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Date: Fri, 25 Nov 2016 16:39:55 +0100
From: Paolo Abeni <pabeni@...hat.com>
To: netdev@...r.kernel.org
Cc: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jesper Dangaard Brouer <brouer@...hat.com>,
Hannes Frederic Sowa <hannes@...essinduktion.org>,
Sabrina Dubroca <sd@...asysnail.net>
Subject: [PATCH net-next 4/5] net/socket: add helpers for recvmmsg
_skb_try_recv_datagram_batch dequeues multiple skb's from the
socket's receive queue, and runs the bulk_destructor callback under
the receive queue lock.
recvmmsg_ctx_from_user retrieves msghdr information from userspace,
and sets up the kernelspace context for processing one datagram.
recvmmsg_ctx_to_user copies to userspace the results of processing one
datagram.
Signed-off-by: Sabrina Dubroca <sd@...asysnail.net>
Signed-off-by: Paolo Abeni <pabeni@...hat.com>
---
include/linux/skbuff.h | 20 ++++++++++++++++
include/net/sock.h | 19 +++++++++++++++
net/core/datagram.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++
net/socket.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 164 insertions(+)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 9c535fb..5672045 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1598,6 +1598,20 @@ static inline void __skb_insert(struct sk_buff *newsk,
list->qlen++;
}
+static inline void __skb_queue_unsplice(struct sk_buff *first,
+ struct sk_buff *last,
+ unsigned int n,
+ struct sk_buff_head *queue)
+{
+ struct sk_buff *next = last->next, *prev = first->prev;
+
+ queue->qlen -= n;
+ last->next = NULL;
+ first->prev = NULL;
+ next->prev = prev;
+ prev->next = next;
+}
+
static inline void __skb_queue_splice(const struct sk_buff_head *list,
struct sk_buff *prev,
struct sk_buff *next)
@@ -3032,6 +3046,12 @@ static inline void skb_frag_list_init(struct sk_buff *skb)
int __skb_wait_for_more_packets(struct sock *sk, int *err, long *timeo_p,
const struct sk_buff *skb);
+struct sk_buff *__skb_try_recv_datagram_batch(struct sock *sk,
+ unsigned int flags,
+ unsigned int batch,
+ void (*bulk_destructor)(
+ struct sock *sk, int size),
+ int *err);
struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned flags,
void (*destructor)(struct sock *sk,
struct sk_buff *skb),
diff --git a/include/net/sock.h b/include/net/sock.h
index 11126f4..3daf63a 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1534,6 +1534,25 @@ int __sock_cmsg_send(struct sock *sk, struct msghdr *msg, struct cmsghdr *cmsg,
int sock_cmsg_send(struct sock *sk, struct msghdr *msg,
struct sockcm_cookie *sockc);
+struct recvmmsg_ctx {
+ struct iovec iovstack[UIO_FASTIOV];
+ struct msghdr msg_sys;
+ struct sockaddr __user *uaddr;
+ struct sockaddr_storage addr;
+ unsigned long cmsg_ptr;
+ struct iovec *iov;
+};
+
+int recvmmsg_ctx_from_user(struct sock *sk, struct mmsghdr __user *mmsg,
+ unsigned int flags, int nosec,
+ struct recvmmsg_ctx *ctx);
+int recvmmsg_ctx_to_user(struct mmsghdr __user **mmsg, int len,
+ unsigned int flags, struct recvmmsg_ctx *ctx);
+static inline void recvmmsg_ctx_free(struct recvmmsg_ctx *ctx)
+{
+ kfree(ctx->iov);
+}
+
static inline bool sock_recvmmsg_timeout(struct timespec *timeout,
struct timespec64 end_time)
{
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 49816af..90d1aa2 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -301,6 +301,71 @@ struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned int flags,
}
EXPORT_SYMBOL(skb_recv_datagram);
+/**
+ * __skb_try_recv_datagram_batch - Receive a batch of datagram skbuff
+ * @sk: socket
+ * @flags: MSG_ flags
+ * @batch: maximum batch length
+ * @bulk_destructor: invoked under the receive lock on successful dequeue
+ * @err: error code returned
+ * @last: set to last peeked message to inform the wait function
+ * what to look for when peeking
+ *
+ * like __skb_try_recv_datagram, but dequeue a full batch up to the specified
+ * max length. Returned skbs are linked and the list is NULL terminated.
+ * Peeking is not supported.
+ */
+struct sk_buff *__skb_try_recv_datagram_batch(struct sock *sk,
+ unsigned int flags,
+ unsigned int batch,
+ void (*bulk_destructor)(
+ struct sock *sk, int size),
+ int *err)
+{
+ unsigned int datagrams = 0, totalsize = 0;
+ struct sk_buff *skb, *last, *first;
+ struct sk_buff_head *queue;
+
+ *err = sock_error(sk);
+ if (*err)
+ return NULL;
+
+ queue = &sk->sk_receive_queue;
+ spin_lock_bh(&queue->lock);
+ for (;;) {
+ if (!skb_queue_empty(queue))
+ break;
+
+ spin_unlock_bh(&queue->lock);
+
+ if (!sk_can_busy_loop(sk) ||
+ !sk_busy_loop(sk, flags & MSG_DONTWAIT))
+ goto no_packets;
+
+ spin_lock_bh(&queue->lock);
+ }
+
+ last = (struct sk_buff *)queue;
+ first = (struct sk_buff *)queue->next;
+ skb_queue_walk(queue, skb) {
+ last = skb;
+ totalsize += skb->truesize;
+ if (++datagrams == batch)
+ break;
+ }
+ __skb_queue_unsplice(first, last, datagrams, queue);
+
+ if (bulk_destructor)
+ bulk_destructor(sk, totalsize);
+ spin_unlock_bh(&queue->lock);
+ return first;
+
+no_packets:
+ *err = -EAGAIN;
+ return NULL;
+}
+EXPORT_SYMBOL(__skb_try_recv_datagram_batch);
+
void skb_free_datagram(struct sock *sk, struct sk_buff *skb)
{
consume_skb(skb);
diff --git a/net/socket.c b/net/socket.c
index 49e6cd6..ceb627b 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2220,6 +2220,66 @@ long __sys_recvmsg(int fd, struct user_msghdr __user *msg, unsigned flags)
* Linux recvmmsg interface
*/
+int recvmmsg_ctx_from_user(struct sock *sk, struct mmsghdr __user *mmsg,
+ unsigned int flags, int nosec,
+ struct recvmmsg_ctx *ctx)
+{
+ struct user_msghdr __user *msg = (struct user_msghdr __user *)mmsg;
+ struct compat_msghdr __user *msg_compat;
+ ssize_t err;
+
+ ctx->iov = ctx->iovstack;
+ msg_compat = (struct compat_msghdr __user *)mmsg;
+ err = copy_msghdr_from_user_gen(&ctx->msg_sys, flags, msg_compat, msg,
+ &ctx->uaddr, &ctx->iov, &ctx->addr);
+ if (err < 0) {
+ ctx->iov = NULL;
+ return err;
+ }
+
+ ctx->cmsg_ptr = (unsigned long)ctx->msg_sys.msg_control;
+ ctx->msg_sys.msg_flags = flags & MSG_CMSG_MASK;
+
+ /* We assume all kernel code knows the size of sockaddr_storage */
+ ctx->msg_sys.msg_namelen = 0;
+
+ if (nosec)
+ return 0;
+
+ return security_socket_recvmsg(sk->sk_socket, &ctx->msg_sys,
+ msg_data_left(&ctx->msg_sys), flags);
+}
+
+int recvmmsg_ctx_to_user(struct mmsghdr __user **mmsg_ptr, int len,
+ unsigned int flags, struct recvmmsg_ctx *ctx)
+{
+ struct compat_mmsghdr __user *mmsg_compat;
+ struct mmsghdr __user *mmsg = *mmsg_ptr;
+ int err;
+
+ mmsg_compat = (struct compat_mmsghdr __user *)mmsg;
+ err = copy_msghdr_to_user_gen(&ctx->msg_sys, flags,
+ &mmsg_compat->msg_hdr, &mmsg->msg_hdr,
+ ctx->uaddr, &ctx->addr, ctx->cmsg_ptr);
+ if (err)
+ return err;
+
+ if (MSG_CMSG_COMPAT & flags) {
+ err = __put_user(len, &mmsg_compat->msg_len);
+ if (err < 0)
+ return err;
+
+ *mmsg_ptr = (struct mmsghdr __user *)(mmsg_compat + 1);
+ } else {
+ err = put_user(len, &mmsg->msg_len);
+ if (err < 0)
+ return err;
+
+ *mmsg_ptr = mmsg + 1;
+ }
+ return err;
+}
+
static int __proto_recvmmsg(struct socket *sock, struct mmsghdr __user *ummsg,
unsigned int *vlen, unsigned int flags,
struct timespec *timeout,
--
1.8.3.1
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