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Subject[RFC PATCH v9 12/16] Add mp(mediate passthru) device.
Date
From: Xin Xiaohui <xiaohui.xin@intel.com>

The patch add mp(mediate passthru) device, which now
based on vhost-net backend driver and provides proto_ops
to send/receive guest buffers data from/to guest vitio-net
driver.

Signed-off-by: Xin Xiaohui <xiaohui.xin@intel.com>
Signed-off-by: Zhao Yu <yzhao81new@gmail.com>
Reviewed-by: Jeff Dike <jdike@linux.intel.com>
---
drivers/vhost/mpassthru.c | 1419 +++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 1419 insertions(+), 0 deletions(-)
create mode 100644 drivers/vhost/mpassthru.c
diff --git a/drivers/vhost/mpassthru.c b/drivers/vhost/mpassthru.c
new file mode 100644
index 0000000..a5c1456
--- /dev/null
+++ b/drivers/vhost/mpassthru.c
@@ -0,0 +1,1419 @@
+/*
+ * MPASSTHRU - Mediate passthrough device.
+ * Copyright (C) 2009 ZhaoYu, XinXiaohui, Dike, Jeffery G
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#define DRV_NAME "mpassthru"
+#define DRV_DESCRIPTION "Mediate passthru device driver"
+#define DRV_COPYRIGHT "(C) 2009 ZhaoYu, XinXiaohui, Dike, Jeffery G"
+
+#include <linux/compat.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/major.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/poll.h>
+#include <linux/fcntl.h>
+#include <linux/init.h>
+#include <linux/aio.h>
+
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/miscdevice.h>
+#include <linux/ethtool.h>
+#include <linux/rtnetlink.h>
+#include <linux/if.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/crc32.h>
+#include <linux/nsproxy.h>
+#include <linux/uaccess.h>
+#include <linux/virtio_net.h>
+#include <linux/mpassthru.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#include <net/rtnetlink.h>
+#include <net/sock.h>
+
+#include <asm/system.h>
+
+/* Uncomment to enable debugging */
+/* #define MPASSTHRU_DEBUG 1 */
+
+#ifdef MPASSTHRU_DEBUG
+static int debug;
+
+#define DBG if (mp->debug) printk
+#define DBG1 if (debug == 2) printk
+#else
+#define DBG(a...)
+#define DBG1(a...)
+#endif
+
+#define COPY_THRESHOLD (L1_CACHE_BYTES * 4)
+#define COPY_HDR_LEN (L1_CACHE_BYTES < 64 ? 64 : L1_CACHE_BYTES)
+
+struct frag {
+ u16 offset;
+ u16 size;
+};
+
+#define HASH_BUCKETS (8192*2)
+
+struct page_info {
+ struct list_head list;
+ struct page_info *next;
+ struct page_info *prev;
+ int header;
+ /* indicate the actual length of bytes
+ * send/recv in the external buffers
+ */
+ int total;
+ int offset;
+ struct page *pages[MAX_SKB_FRAGS+1];
+ struct skb_frag_struct frag[MAX_SKB_FRAGS+1];
+ struct sk_buff *skb;
+ struct page_ctor *ctor;
+
+ /* The pointer relayed to skb, to indicate
+ * it's a external allocated skb or kernel
+ */
+ struct skb_ext_page ext_page;
+ struct skb_shared_info ushinfo;
+
+#define INFO_READ 0
+#define INFO_WRITE 1
+ unsigned flags;
+ unsigned pnum;
+
+ /* It's meaningful for receive, means
+ * the max length allowed
+ */
+ size_t len;
+
+ /* The fields after that is for backend
+ * driver, now for vhost-net.
+ */
+
+ struct kiocb *iocb;
+ unsigned int desc_pos;
+ struct iovec hdr[MAX_SKB_FRAGS + 2];
+ struct iovec iov[MAX_SKB_FRAGS + 2];
+};
+
+static struct kmem_cache *ext_page_info_cache;
+
+struct page_ctor {
+ struct list_head readq;
+ int wq_len;
+ int rq_len;
+ spinlock_t read_lock;
+ /* record the locked pages */
+ int lock_pages;
+ struct rlimit o_rlim;
+ struct net_device *dev;
+ struct mpassthru_port port;
+ struct page_info **hash_table;
+};
+
+struct mp_struct {
+ struct mp_file *mfile;
+ struct net_device *dev;
+ struct page_ctor *ctor;
+ struct socket socket;
+
+#ifdef MPASSTHRU_DEBUG
+ int debug;
+#endif
+};
+
+struct mp_file {
+ atomic_t count;
+ struct mp_struct *mp;
+ struct net *net;
+};
+
+struct mp_sock {
+ struct sock sk;
+ struct mp_struct *mp;
+};
+
+static int mp_dev_change_flags(struct net_device *dev, unsigned flags)
+{
+ int ret = 0;
+
+ rtnl_lock();
+ ret = dev_change_flags(dev, flags);
+ rtnl_unlock();
+
+ if (ret < 0)
+ printk(KERN_ERR "failed to change dev state of %s", dev->name);
+
+ return ret;
+}
+
+/* The main function to allocate external buffers */
+static struct skb_ext_page *page_ctor(struct mpassthru_port *port,
+ struct sk_buff *skb, int npages)
+{
+ int i;
+ unsigned long flags;
+ struct page_ctor *ctor;
+ struct page_info *info = NULL;
+
+ ctor = container_of(port, struct page_ctor, port);
+
+ spin_lock_irqsave(&ctor->read_lock, flags);
+ if (!list_empty(&ctor->readq)) {
+ info = list_first_entry(&ctor->readq, struct page_info, list);
+ list_del(&info->list);
+ ctor->rq_len--;
+ }
+ spin_unlock_irqrestore(&ctor->read_lock, flags);
+ if (!info)
+ return NULL;
+
+ for (i = 0; i < info->pnum; i++)
+ get_page(info->pages[i]);
+ info->skb = skb;
+ return &info->ext_page;
+}
+
+static struct page_info *mp_hash_lookup(struct page_ctor *ctor,
+ struct page *page);
+static struct page_info *mp_hash_delete(struct page_ctor *ctor,
+ struct page_info *info);
+
+static struct skb_ext_page *mp_lookup(struct net_device *dev,
+ struct page *page)
+{
+ struct mp_struct *mp =
+ container_of(dev->mp_port->sock->sk, struct mp_sock, sk)->mp;
+ struct page_ctor *ctor = mp->ctor;
+ struct page_info *info;
+
+ info = mp_hash_lookup(ctor, page);
+ if (!info)
+ return NULL;
+ return &info->ext_page;
+}
+
+static int page_ctor_attach(struct mp_struct *mp)
+{
+ int rc;
+ struct page_ctor *ctor;
+ struct net_device *dev = mp->dev;
+
+ /* locked by mp_mutex */
+ if (mp->ctor)
+ return -EBUSY;
+
+ ctor = kzalloc(sizeof(*ctor), GFP_KERNEL);
+ if (!ctor)
+ return -ENOMEM;
+ rc = netdev_mp_port_prep(dev, &ctor->port);
+ if (rc)
+ goto fail;
+
+ INIT_LIST_HEAD(&ctor->readq);
+ spin_lock_init(&ctor->read_lock);
+ ctor->hash_table = kzalloc(sizeof(struct page_info *) * HASH_BUCKETS,
+ GFP_KERNEL);
+ if (!ctor->hash_table)
+ goto fail_hash;
+
+ ctor->rq_len = 0;
+ ctor->wq_len = 0;
+
+ dev_hold(dev);
+ ctor->dev = dev;
+ ctor->port.ctor = page_ctor;
+ ctor->port.sock = &mp->socket;
+ ctor->port.hash = mp_lookup;
+ ctor->lock_pages = 0;
+
+ /* locked by mp_mutex */
+ dev->mp_port = &ctor->port;
+ mp->ctor = ctor;
+
+ return 0;
+
+fail_hash:
+ kfree(ctor->hash_table);
+
+fail:
+ kfree(ctor);
+ dev_put(dev);
+
+ return rc;
+}
+
+struct page_info *info_dequeue(struct page_ctor *ctor)
+{
+ unsigned long flags;
+ struct page_info *info = NULL;
+ spin_lock_irqsave(&ctor->read_lock, flags);
+ if (!list_empty(&ctor->readq)) {
+ info = list_first_entry(&ctor->readq,
+ struct page_info, list);
+ list_del(&info->list);
+ ctor->rq_len--;
+ }
+ spin_unlock_irqrestore(&ctor->read_lock, flags);
+ return info;
+}
+
+static int set_memlock_rlimit(struct page_ctor *ctor, int resource,
+ unsigned long cur, unsigned long max)
+{
+ struct rlimit new_rlim, *old_rlim;
+ int retval;
+
+ if (resource != RLIMIT_MEMLOCK)
+ return -EINVAL;
+ new_rlim.rlim_cur = cur;
+ new_rlim.rlim_max = max;
+
+ old_rlim = current->signal->rlim + resource;
+
+ /* remember the old rlimit value when backend enabled */
+ ctor->o_rlim.rlim_cur = old_rlim->rlim_cur;
+ ctor->o_rlim.rlim_max = old_rlim->rlim_max;
+
+ if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
+ !capable(CAP_SYS_RESOURCE))
+ return -EPERM;
+
+ retval = security_task_setrlimit(resource, &new_rlim);
+ if (retval)
+ return retval;
+
+ task_lock(current->group_leader);
+ *old_rlim = new_rlim;
+ task_unlock(current->group_leader);
+ return 0;
+}
+
+static void relinquish_resource(struct page_ctor *ctor)
+{
+ if (!(ctor->dev->flags & IFF_UP) &&
+ !(ctor->wq_len + ctor->rq_len))
+ printk(KERN_INFO "relinquish_resource\n");
+}
+
+static void mp_ki_dtor(struct kiocb *iocb)
+{
+ struct page_info *info = (struct page_info *)(iocb->private);
+ int i;
+
+ if (info->flags == INFO_READ) {
+ for (i = 0; i < info->pnum; i++) {
+ if (info->pages[i]) {
+ set_page_dirty_lock(info->pages[i]);
+ put_page(info->pages[i]);
+ }
+ }
+ mp_hash_delete(info->ctor, info);
+ if (info->skb) {
+ info->skb->destructor = NULL;
+ kfree_skb(info->skb);
+ }
+ info->ctor->rq_len--;
+ } else
+ info->ctor->wq_len--;
+ /* Decrement the number of locked pages */
+ info->ctor->lock_pages -= info->pnum;
+ kmem_cache_free(ext_page_info_cache, info);
+ relinquish_resource(info->ctor);
+
+ return;
+}
+
+static struct kiocb *create_iocb(struct page_info *info, int size)
+{
+ struct kiocb *iocb = NULL;
+
+ iocb = info->iocb;
+ if (!iocb)
+ return iocb;
+ iocb->ki_flags = 0;
+ iocb->ki_users = 1;
+ iocb->ki_key = 0;
+ iocb->ki_ctx = NULL;
+ iocb->ki_cancel = NULL;
+ iocb->ki_retry = NULL;
+ iocb->ki_eventfd = NULL;
+ iocb->ki_pos = info->desc_pos;
+ iocb->ki_nbytes = size;
+ iocb->ki_dtor(iocb);
+ iocb->private = (void *)info;
+ iocb->ki_dtor = mp_ki_dtor;
+
+ return iocb;
+}
+
+static int page_ctor_detach(struct mp_struct *mp)
+{
+ struct page_ctor *ctor;
+ struct page_info *info;
+ int i;
+
+ /* locked by mp_mutex */
+ ctor = mp->ctor;
+ if (!ctor)
+ return -ENODEV;
+
+ while ((info = info_dequeue(ctor))) {
+ for (i = 0; i < info->pnum; i++)
+ if (info->pages[i])
+ put_page(info->pages[i]);
+ create_iocb(info, 0);
+ ctor->rq_len--;
+ kmem_cache_free(ext_page_info_cache, info);
+ }
+
+ relinquish_resource(ctor);
+
+ set_memlock_rlimit(ctor, RLIMIT_MEMLOCK,
+ ctor->o_rlim.rlim_cur,
+ ctor->o_rlim.rlim_max);
+
+ /* locked by mp_mutex */
+ ctor->dev->mp_port = NULL;
+ dev_put(ctor->dev);
+
+ mp->ctor = NULL;
+ kfree(ctor->hash_table);
+ kfree(ctor);
+ return 0;
+}
+
+static void __mp_detach(struct mp_struct *mp)
+{
+ mp->mfile = NULL;
+
+ mp_dev_change_flags(mp->dev, mp->dev->flags & ~IFF_UP);
+ page_ctor_detach(mp);
+ mp_dev_change_flags(mp->dev, mp->dev->flags | IFF_UP);
+
+ /* Drop the extra count on the net device */
+ dev_put(mp->dev);
+}
+
+static DEFINE_MUTEX(mp_mutex);
+
+static void mp_detach(struct mp_struct *mp)
+{
+ mutex_lock(&mp_mutex);
+ __mp_detach(mp);
+ mutex_unlock(&mp_mutex);
+}
+
+static struct mp_struct *mp_get(struct mp_file *mfile)
+{
+ struct mp_struct *mp = NULL;
+ if (atomic_inc_not_zero(&mfile->count))
+ mp = mfile->mp;
+
+ return mp;
+}
+
+static void mp_put(struct mp_file *mfile)
+{
+ if (atomic_dec_and_test(&mfile->count))
+ mp_detach(mfile->mp);
+}
+
+static void iocb_tag(struct kiocb *iocb)
+{
+ iocb->ki_flags = 1;
+}
+
+/* The callback to destruct the external buffers or skb */
+static void page_dtor(struct skb_ext_page *ext_page)
+{
+ struct page_info *info;
+ struct page_ctor *ctor;
+ struct sock *sk;
+ struct sk_buff *skb;
+
+ if (!ext_page)
+ return;
+ info = container_of(ext_page, struct page_info, ext_page);
+ if (!info)
+ return;
+ ctor = info->ctor;
+ skb = info->skb;
+
+ if (info->flags == INFO_READ) {
+ create_iocb(info, 0);
+ return;
+ }
+
+ /* For transmit, we should wait for the DMA finish by hardware.
+ * Queue the notifier to wake up the backend driver
+ */
+
+ iocb_tag(info->iocb);
+ sk = ctor->port.sock->sk;
+ sk->sk_write_space(sk);
+
+ return;
+}
+
+/* For small exteranl buffers transmit, we don't need to call
+ * get_user_pages().
+ */
+static struct page_info *alloc_small_page_info(struct page_ctor *ctor,
+ struct kiocb *iocb, int total)
+{
+ struct page_info *info =
+ kmem_cache_zalloc(ext_page_info_cache, GFP_KERNEL);
+
+ if (!info)
+ return NULL;
+ info->total = total;
+ info->ext_page.dtor = page_dtor;
+ info->ctor = ctor;
+ info->flags = INFO_WRITE;
+ info->iocb = iocb;
+ return info;
+}
+
+typedef u32 key_mp_t;
+static inline key_mp_t mp_hash(struct page *page, int buckets)
+{
+ key_mp_t k;
+
+ k = ((((unsigned long)page << 32UL) >> 32UL) / 0x38) % buckets ;
+ return k;
+}
+
+static void mp_hash_insert(struct page_ctor *ctor,
+ struct page *page, struct page_info *page_info)
+{
+ struct page_info *tmp;
+ key_mp_t key = mp_hash(page, HASH_BUCKETS);
+ if (!ctor->hash_table[key]) {
+ ctor->hash_table[key] = page_info;
+ return;
+ }
+
+ tmp = ctor->hash_table[key];
+ while (tmp->next)
+ tmp = tmp->next;
+
+ tmp->next = page_info;
+ page_info->prev = tmp;
+ return;
+}
+
+static struct page_info *mp_hash_delete(struct page_ctor *ctor,
+ struct page_info *info)
+{
+ key_mp_t key = mp_hash(info->pages[0], HASH_BUCKETS);
+ struct page_info *tmp = NULL;
+ int i;
+
+ tmp = ctor->hash_table[key];
+ while (tmp) {
+ if (tmp == info) {
+ if (!tmp->prev) {
+ ctor->hash_table[key] = tmp->next;
+ if (tmp->next)
+ tmp->next->prev = NULL;
+ } else {
+ tmp->prev->next = tmp->next;
+ if (tmp->next)
+ tmp->next->prev = tmp->prev;
+ }
+ return tmp;
+ }
+ tmp = tmp->next;
+ }
+ return tmp;
+}
+
+static struct page_info *mp_hash_lookup(struct page_ctor *ctor,
+ struct page *page)
+{
+ key_mp_t key = mp_hash(page, HASH_BUCKETS);
+ struct page_info *tmp = NULL;
+
+ int i;
+ tmp = ctor->hash_table[key];
+ while (tmp) {
+ for (i = 0; i < tmp->pnum; i++) {
+ if (tmp->pages[i] == page)
+ return tmp;
+ }
+ tmp = tmp->next;
+ }
+ return tmp;
+}
+
+/* The main function to transform the guest user space address
+ * to host kernel address via get_user_pages(). Thus the hardware
+ * can do DMA directly to the external buffer address.
+ */
+static struct page_info *alloc_page_info(struct page_ctor *ctor,
+ struct kiocb *iocb, struct iovec *iov,
+ int count, struct frag *frags,
+ int npages, int total)
+{
+ int rc;
+ int i, j, n = 0;
+ int len;
+ unsigned long base, lock_limit;
+ struct page_info *info = NULL;
+
+ lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+ lock_limit >>= PAGE_SHIFT;
+
+ if (ctor->lock_pages + count > lock_limit && npages) {
+ printk(KERN_INFO "exceed the locked memory rlimit.");
+ return NULL;
+ }
+
+ info = kmem_cache_zalloc(ext_page_info_cache, GFP_KERNEL);
+
+ if (!info)
+ return NULL;
+
+ for (i = j = 0; i < count; i++) {
+ base = (unsigned long)iov[i].iov_base;
+ len = iov[i].iov_len;
+
+ if (!len)
+ continue;
+ n = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
+
+ rc = get_user_pages_fast(base, n, npages ? 1 : 0,
+ &info->pages[j]);
+ if (rc != n)
+ goto failed;
+
+ while (n--) {
+ frags[j].offset = base & ~PAGE_MASK;
+ frags[j].size = min_t(int, len,
+ PAGE_SIZE - frags[j].offset);
+ len -= frags[j].size;
+ base += frags[j].size;
+ j++;
+ }
+ }
+
+#ifdef CONFIG_HIGHMEM
+ if (npages && !(dev->features & NETIF_F_HIGHDMA)) {
+ for (i = 0; i < j; i++) {
+ if (PageHighMem(info->pages[i]))
+ goto failed;
+ }
+ }
+#endif
+
+ info->total = total;
+ info->ext_page.dtor = page_dtor;
+ info->ext_page.page = info->pages[0];
+ info->ctor = ctor;
+ info->pnum = j;
+ info->iocb = iocb;
+ if (!npages)
+ info->flags = INFO_WRITE;
+ if (info->flags == INFO_READ) {
+ if (frags[0].offset == 0 && iocb->ki_iovec[0].iov_len) {
+ frags[0].offset = iocb->ki_iovec[0].iov_len;
+ ctor->port.vnet_hlen = iocb->ki_iovec[0].iov_len;
+ }
+ for (i = 0; i < j; i++)
+ mp_hash_insert(ctor, info->pages[i], info);
+ }
+ /* increment the number of locked pages */
+ ctor->lock_pages += j;
+ return info;
+
+failed:
+ for (i = 0; i < j; i++)
+ put_page(info->pages[i]);
+
+ kmem_cache_free(ext_page_info_cache, info);
+
+ return NULL;
+}
+
+static void mp_sock_destruct(struct sock *sk)
+{
+ struct mp_struct *mp = container_of(sk, struct mp_sock, sk)->mp;
+ kfree(mp);
+}
+
+static void mp_sock_state_change(struct sock *sk)
+{
+ if (sk_has_sleeper(sk))
+ wake_up_interruptible_sync_poll(sk->sk_sleep, POLLIN);
+}
+
+static void mp_sock_write_space(struct sock *sk)
+{
+ if (sk_has_sleeper(sk))
+ wake_up_interruptible_sync_poll(sk->sk_sleep, POLLOUT);
+}
+
+static void mp_sock_data_ready(struct sock *sk, int coming)
+{
+ struct mp_struct *mp = container_of(sk, struct mp_sock, sk)->mp;
+ struct page_ctor *ctor = NULL;
+ struct sk_buff *skb = NULL;
+ struct page_info *info = NULL;
+ int len;
+
+ struct virtio_net_hdr_mrg_rxbuf hdr = {
+ .hdr.flags = 0,
+ .hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE
+ };
+
+ ctor = mp->ctor;
+ if (!ctor)
+ return;
+
+ while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
+ struct page *page;
+ int off;
+ int size = 0, i = 0;
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+ struct skb_ext_page *ext_page =
+ (struct skb_ext_page *)(shinfo->destructor_arg);
+ int free = 0;
+
+ if (skb->ip_summed == CHECKSUM_COMPLETE)
+ DBG(KERN_INFO "csum %d\n", skb->ip_summed);
+
+ if (shinfo->frags[0].page == ext_page->page) {
+ info = container_of(ext_page, struct page_info, ext_page);
+ if (shinfo->nr_frags)
+ hdr.num_buffers = shinfo->nr_frags;
+ else
+ hdr.num_buffers = shinfo->nr_frags + 1;
+ } else {
+ info = container_of(ext_page, struct page_info, ext_page);
+ hdr.num_buffers = shinfo->nr_frags + 1;
+ }
+ skb_push(skb, ETH_HLEN);
+
+ if (skb_is_gso(skb)) {
+ hdr.hdr.hdr_len = skb_headlen(skb);
+ hdr.hdr.gso_size = shinfo->gso_size;
+ if (shinfo->gso_type & SKB_GSO_TCPV4)
+ hdr.hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+ else if (shinfo->gso_type & SKB_GSO_TCPV6)
+ hdr.hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+ else if (shinfo->gso_type & SKB_GSO_UDP)
+ hdr.hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
+ else
+ BUG();
+ if (shinfo->gso_type & SKB_GSO_TCP_ECN)
+ hdr.hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
+
+ } else
+ hdr.hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
+
+ if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ hdr.hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+ hdr.hdr.csum_start =
+ skb->csum_start - skb_headroom(skb);
+ hdr.hdr.csum_offset = skb->csum_offset;
+ }
+
+ info->skb = NULL;
+ off = info->hdr[0].iov_len;
+ len = memcpy_toiovec(info->iov, (unsigned char *)&hdr, off);
+ if (len) {
+ DBG(KERN_INFO
+ "Unable to write vnet_hdr at addr %p: %d\n",
+ info->iov_base, len);
+ goto clean;
+ }
+
+ memcpy_toiovec(info->iov, skb->data, skb_headlen(skb));
+
+ info->iocb->ki_left = hdr.num_buffers;
+ if (shinfo->frags[0].page == ext_page->page) {
+ size = shinfo->frags[0].size +
+ shinfo->frags[0].page_offset - off;
+ i = 1;
+ } else {
+ size = skb_headlen(skb);
+ i = 0;
+ }
+ create_iocb(info, off + size);
+ for (i = i; i < shinfo->nr_frags; i++) {
+ page = shinfo->frags[i].page;
+ info = mp_hash_lookup(ctor, shinfo->frags[i].page);
+ info->skb = NULL;
+ create_iocb(info, shinfo->frags[i].size);
+ }
+ info->skb = skb;
+ shinfo->nr_frags = 0;
+ shinfo->destructor_arg = NULL;
+ continue;
+clean:
+ kfree_skb(skb);
+ for (i = 0; info->pages[i]; i++)
+ put_page(info->pages[i]);
+ kmem_cache_free(ext_page_info_cache, info);
+ }
+ return;
+}
+
+static inline struct sk_buff *mp_alloc_skb(struct sock *sk, size_t prepad,
+ size_t len, size_t linear,
+ int noblock, int *err)
+{
+ struct sk_buff *skb;
+
+ /* Under a page? Don't bother with paged skb. */
+ if (prepad + len < PAGE_SIZE || !linear)
+ linear = len;
+
+ skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
+ err);
+ if (!skb)
+ return NULL;
+
+ skb_reserve(skb, prepad);
+ skb_put(skb, linear);
+ skb->data_len = len - linear;
+ skb->len += len - linear;
+
+ return skb;
+}
+
+static int mp_skb_from_vnet_hdr(struct sk_buff *skb,
+ struct virtio_net_hdr *vnet_hdr)
+{
+ unsigned short gso_type = 0;
+ if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+ switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
+ case VIRTIO_NET_HDR_GSO_TCPV4:
+ gso_type = SKB_GSO_TCPV4;
+ break;
+ case VIRTIO_NET_HDR_GSO_TCPV6:
+ gso_type = SKB_GSO_TCPV6;
+ break;
+ case VIRTIO_NET_HDR_GSO_UDP:
+ gso_type = SKB_GSO_UDP;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
+ gso_type |= SKB_GSO_TCP_ECN;
+
+ if (vnet_hdr->gso_size == 0)
+ return -EINVAL;
+ }
+
+ if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+ if (!skb_partial_csum_set(skb, vnet_hdr->csum_start,
+ vnet_hdr->csum_offset))
+ return -EINVAL;
+ }
+
+ if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+ skb_shinfo(skb)->gso_size = vnet_hdr->gso_size;
+ skb_shinfo(skb)->gso_type = gso_type;
+
+ /* Header must be checked, and gso_segs computed. */
+ skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
+ skb_shinfo(skb)->gso_segs = 0;
+ }
+ return 0;
+}
+
+static int mp_sendmsg(struct kiocb *iocb, struct socket *sock,
+ struct msghdr *m, size_t total_len)
+{
+ struct mp_struct *mp = container_of(sock->sk, struct mp_sock, sk)->mp;
+ struct virtio_net_hdr vnet_hdr = {0};
+ int hdr_len = 0;
+ struct page_ctor *ctor;
+ struct iovec *iov = m->msg_iov;
+ struct page_info *info = NULL;
+ struct frag frags[MAX_SKB_FRAGS];
+ struct sk_buff *skb;
+ int count = m->msg_iovlen;
+ int total = 0, header, n, i, len, rc;
+ unsigned long base;
+
+ ctor = mp->ctor;
+ if (!ctor)
+ return -ENODEV;
+
+ total = iov_length(iov, count);
+
+ if (total < ETH_HLEN)
+ return -EINVAL;
+
+ if (total <= COPY_THRESHOLD)
+ goto copy;
+
+ n = 0;
+ for (i = 0; i < count; i++) {
+ base = (unsigned long)iov[i].iov_base;
+ len = iov[i].iov_len;
+ if (!len)
+ continue;
+ n += ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
+ if (n > MAX_SKB_FRAGS)
+ return -EINVAL;
+ }
+
+copy:
+ hdr_len = sizeof(vnet_hdr);
+ if ((total - iocb->ki_iovec[0].iov_len) < 0)
+ return -EINVAL;
+
+ rc = memcpy_fromiovecend((void *)&vnet_hdr, iocb->ki_iovec, 0, hdr_len);
+ if (rc < 0)
+ return -EINVAL;
+
+ if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
+ vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 >
+ vnet_hdr.hdr_len)
+ vnet_hdr.hdr_len = vnet_hdr.csum_start +
+ vnet_hdr.csum_offset + 2;
+
+ if (vnet_hdr.hdr_len > total)
+ return -EINVAL;
+
+ header = total > COPY_THRESHOLD ? COPY_HDR_LEN : total;
+
+ skb = mp_alloc_skb(sock->sk, NET_IP_ALIGN, header,
+ iocb->ki_iovec[0].iov_len, 1, &rc);
+
+ if (!skb)
+ goto drop;
+
+ skb_set_network_header(skb, ETH_HLEN);
+ memcpy_fromiovec(skb->data, iov, header);
+
+ skb_reset_mac_header(skb);
+ skb->protocol = eth_hdr(skb)->h_proto;
+
+ rc = mp_skb_from_vnet_hdr(skb, &vnet_hdr);
+ if (rc)
+ goto drop;
+
+ if (header == total) {
+ rc = total;
+ info = alloc_small_page_info(ctor, iocb, total);
+ } else {
+ info = alloc_page_info(ctor, iocb, iov, count, frags, 0, total);
+ if (info)
+ for (i = 0; info->pages[i]; i++) {
+ skb_add_rx_frag(skb, i, info->pages[i],
+ frags[i].offset, frags[i].size);
+ info->pages[i] = NULL;
+ }
+ }
+ if (info != NULL) {
+ info->desc_pos = iocb->ki_pos;
+ info->total = total;
+ info->skb = skb;
+ skb_shinfo(skb)->destructor_arg = &info->ext_page;
+ skb->dev = mp->dev;
+ ctor->wq_len++;
+ create_iocb(info, info->total);
+ dev_queue_xmit(skb);
+ if (!ctor->rq_len)
+ sock->sk->sk_state_change(sock->sk);
+ return 0;
+ }
+drop:
+ kfree_skb(skb);
+ if (info) {
+ for (i = 0; info->pages[i]; i++)
+ put_page(info->pages[i]);
+ kmem_cache_free(ext_page_info_cache, info);
+ }
+ mp->dev->stats.tx_dropped++;
+ return -ENOMEM;
+}
+
+static int mp_recvmsg(struct kiocb *iocb, struct socket *sock,
+ struct msghdr *m, size_t total_len,
+ int flags)
+{
+ struct mp_struct *mp = container_of(sock->sk, struct mp_sock, sk)->mp;
+ struct page_ctor *ctor;
+ struct iovec *iov = m->msg_iov;
+ int count = m->msg_iovlen;
+ int npages, payload;
+ struct page_info *info;
+ struct frag frags[MAX_SKB_FRAGS];
+ unsigned long base;
+ int i, len;
+ unsigned long flag;
+
+ if (!(flags & MSG_DONTWAIT))
+ return -EINVAL;
+
+ ctor = mp->ctor;
+ if (!ctor)
+ return -EINVAL;
+
+ /* Error detections in case invalid external buffer */
+ if (count > 2 && iov[1].iov_len < ctor->port.hdr_len &&
+ mp->dev->features & NETIF_F_SG) {
+ return -EINVAL;
+ }
+
+ npages = ctor->port.npages;
+ payload = ctor->port.data_len;
+
+ /* If KVM guest virtio-net FE driver use SG feature */
+ if (count > 2) {
+ for (i = 2; i < count; i++) {
+ base = (unsigned long)iov[i].iov_base & ~PAGE_MASK;
+ len = iov[i].iov_len;
+ if (npages == 1)
+ len = min_t(int, len, PAGE_SIZE - base);
+ else if (base)
+ break;
+ payload -= len;
+ if (payload <= 0)
+ goto proceed;
+ if (npages == 1 || (len & ~PAGE_MASK))
+ break;
+ }
+ }
+
+ if ((((unsigned long)iov[1].iov_base & ~PAGE_MASK)
+ - NET_SKB_PAD - NET_IP_ALIGN) >= 0)
+ goto proceed;
+
+ return -EINVAL;
+
+proceed:
+ /* skip the virtnet head */
+ if (count > 1) {
+ iov++;
+ count--;
+ }
+
+ if (!ctor->lock_pages || !ctor->rq_len) {
+ set_memlock_rlimit(ctor, RLIMIT_MEMLOCK,
+ iocb->ki_user_data * 4096 * 2,
+ iocb->ki_user_data * 4096 * 2);
+ }
+
+ /* Translate address to kernel */
+ info = alloc_page_info(ctor, iocb, iov, count, frags, npages, 0);
+ if (!info)
+ return -ENOMEM;
+ info->len = total_len;
+ info->hdr[0].iov_base = iocb->ki_iovec[0].iov_base;
+ info->hdr[0].iov_len = iocb->ki_iovec[0].iov_len;
+ iocb->ki_iovec[0].iov_len = 0;
+ iocb->ki_left = 0;
+ info->offset = frags[0].offset;
+ info->desc_pos = iocb->ki_pos;
+
+ if (count > 1) {
+ iov--;
+ count++;
+ }
+
+ memcpy(info->iov, iov, sizeof(struct iovec) * count);
+
+ spin_lock_irqsave(&ctor->read_lock, flag);
+ list_add_tail(&info->list, &ctor->readq);
+ spin_unlock_irqrestore(&ctor->read_lock, flag);
+
+ ctor->rq_len++;
+
+ return 0;
+}
+
+/* Ops structure to mimic raw sockets with mp device */
+static const struct proto_ops mp_socket_ops = {
+ .sendmsg = mp_sendmsg,
+ .recvmsg = mp_recvmsg,
+};
+
+static struct proto mp_proto = {
+ .name = "mp",
+ .owner = THIS_MODULE,
+ .obj_size = sizeof(struct mp_sock),
+};
+
+static int mp_chr_open(struct inode *inode, struct file * file)
+{
+ struct mp_file *mfile;
+ cycle_kernel_lock();
+ DBG1(KERN_INFO "mp: mp_chr_open\n");
+
+ mfile = kzalloc(sizeof(*mfile), GFP_KERNEL);
+ if (!mfile)
+ return -ENOMEM;
+ atomic_set(&mfile->count, 0);
+ mfile->mp = NULL;
+ mfile->net = get_net(current->nsproxy->net_ns);
+ file->private_data = mfile;
+ return 0;
+}
+
+static int mp_attach(struct mp_struct *mp, struct file *file)
+{
+ struct mp_file *mfile = file->private_data;
+ int err;
+
+ netif_tx_lock_bh(mp->dev);
+
+ err = -EINVAL;
+
+ if (mfile->mp)
+ goto out;
+
+ err = -EBUSY;
+ if (mp->mfile)
+ goto out;
+
+ err = 0;
+ mfile->mp = mp;
+ mp->mfile = mfile;
+ mp->socket.file = file;
+ dev_hold(mp->dev);
+ sock_hold(mp->socket.sk);
+ atomic_inc(&mfile->count);
+
+out:
+ netif_tx_unlock_bh(mp->dev);
+ return err;
+}
+
+static int do_unbind(struct mp_file *mfile)
+{
+ struct mp_struct *mp = mp_get(mfile);
+
+ if (!mp)
+ return -EINVAL;
+
+ mp_detach(mp);
+ sock_put(mp->socket.sk);
+ mp_put(mfile);
+ return 0;
+}
+
+static long mp_chr_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct mp_file *mfile = file->private_data;
+ struct mp_struct *mp;
+ struct net_device *dev;
+ void __user* argp = (void __user *)arg;
+ struct ifreq ifr;
+ struct sock *sk;
+ int ret;
+
+ ret = -EINVAL;
+
+ switch (cmd) {
+ case MPASSTHRU_BINDDEV:
+ ret = -EFAULT;
+ if (copy_from_user(&ifr, argp, sizeof ifr))
+ break;
+
+ ifr.ifr_name[IFNAMSIZ-1] = '\0';
+
+ ret = -ENODEV;
+ dev = dev_get_by_name(mfile->net, ifr.ifr_name);
+ if (!dev)
+ break;
+
+ mutex_lock(&mp_mutex);
+
+ ret = -EBUSY;
+
+ /* the device can be only bind once */
+ if (dev_is_mpassthru(dev))
+ goto err_dev_put;
+
+ mp = mfile->mp;
+ if (mp)
+ goto err_dev_put;
+
+ mp = kzalloc(sizeof(*mp), GFP_KERNEL);
+ if (!mp) {
+ ret = -ENOMEM;
+ goto err_dev_put;
+ }
+ mp->dev = dev;
+ ret = -ENOMEM;
+
+ sk = sk_alloc(mfile->net, AF_UNSPEC, GFP_KERNEL, &mp_proto);
+ if (!sk)
+ goto err_free_mp;
+
+ init_waitqueue_head(&mp->socket.wait);
+ mp->socket.ops = &mp_socket_ops;
+ sock_init_data(&mp->socket, sk);
+ sk->sk_sndbuf = INT_MAX;
+ container_of(sk, struct mp_sock, sk)->mp = mp;
+
+ sk->sk_destruct = mp_sock_destruct;
+ sk->sk_data_ready = mp_sock_data_ready;
+ sk->sk_write_space = mp_sock_write_space;
+ sk->sk_state_change = mp_sock_state_change;
+ ret = mp_attach(mp, file);
+ if (ret < 0)
+ goto err_free_sk;
+
+ ret = page_ctor_attach(mp);
+ if (ret < 0)
+ goto err_free_sk;
+ mp_dev_change_flags(mp->dev, mp->dev->flags & (~IFF_UP));
+ mp_dev_change_flags(mp->dev, mp->dev->flags | IFF_UP);
+ sk->sk_state_change(sk);
+out:
+ mutex_unlock(&mp_mutex);
+ break;
+err_free_sk:
+ sk_free(sk);
+err_free_mp:
+ kfree(mp);
+err_dev_put:
+ dev_put(dev);
+ goto out;
+
+ case MPASSTHRU_UNBINDDEV:
+ ret = do_unbind(mfile);
+ break;
+
+ default:
+ break;
+ }
+ return ret;
+}
+
+static unsigned int mp_chr_poll(struct file *file, poll_table * wait)
+{
+ struct mp_file *mfile = file->private_data;
+ struct mp_struct *mp = mp_get(mfile);
+ struct sock *sk;
+ unsigned int mask = 0;
+
+ if (!mp)
+ return POLLERR;
+
+ sk = mp->socket.sk;
+
+ poll_wait(file, &mp->socket.wait, wait);
+
+ if (!skb_queue_empty(&sk->sk_receive_queue))
+ mask |= POLLIN | POLLRDNORM;
+
+ if (sock_writeable(sk) ||
+ (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
+ sock_writeable(sk)))
+ mask |= POLLOUT | POLLWRNORM;
+
+ if (mp->dev->reg_state != NETREG_REGISTERED)
+ mask = POLLERR;
+
+ mp_put(mfile);
+ return mask;
+}
+
+static ssize_t mp_chr_aio_write(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long count, loff_t pos)
+{
+ struct file *file = iocb->ki_filp;
+ struct mp_struct *mp = mp_get(file->private_data);
+ struct sock *sk = mp->socket.sk;
+ struct sk_buff *skb;
+ int len, err;
+ ssize_t result = 0;
+
+ if (!mp)
+ return -EBADFD;
+
+ /* currently, async is not supported.
+ * but we may support real async aio from user application,
+ * maybe qemu virtio-net backend.
+ */
+ if (!is_sync_kiocb(iocb))
+ return -EFAULT;
+
+ len = iov_length(iov, count);
+
+ if (unlikely(len) < ETH_HLEN)
+ return -EINVAL;
+
+ skb = sock_alloc_send_skb(sk, len + NET_IP_ALIGN,
+ file->f_flags & O_NONBLOCK, &err);
+
+ if (!skb)
+ return -EFAULT;
+
+ skb_reserve(skb, NET_IP_ALIGN);
+ skb_put(skb, len);
+
+ if (skb_copy_datagram_from_iovec(skb, 0, iov, 0, len)) {
+ kfree_skb(skb);
+ return -EAGAIN;
+ }
+
+ skb->protocol = eth_type_trans(skb, mp->dev);
+ skb->dev = mp->dev;
+
+ dev_queue_xmit(skb);
+
+ mp_put(file->private_data);
+ return result;
+}
+
+static int mp_chr_close(struct inode *inode, struct file *file)
+{
+ struct mp_file *mfile = file->private_data;
+
+ /*
+ * Ignore return value since an error only means there was nothing to
+ * do
+ */
+ do_unbind(mfile);
+
+ put_net(mfile->net);
+ kfree(mfile);
+
+ return 0;
+}
+
+#ifdef CONFIG_COMPAT
+static long mp_chr_compat_ioctl(struct file *f, unsigned int ioctl,
+ unsigned long arg)
+{
+ return mp_chr_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static const struct file_operations mp_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = do_sync_write,
+ .aio_write = mp_chr_aio_write,
+ .poll = mp_chr_poll,
+ .unlocked_ioctl = mp_chr_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = mp_chr_compat_ioctl,
+#endif
+ .open = mp_chr_open,
+ .release = mp_chr_close,
+};
+
+static struct miscdevice mp_miscdev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "mp",
+ .nodename = "net/mp",
+ .fops = &mp_fops,
+};
+
+static int mp_device_event(struct notifier_block *unused,
+ unsigned long event, void *ptr)
+{
+ struct net_device *dev = ptr;
+ struct mpassthru_port *port;
+ struct mp_struct *mp = NULL;
+ struct socket *sock = NULL;
+ struct sock *sk;
+
+ port = dev->mp_port;
+ if (port == NULL)
+ return NOTIFY_DONE;
+
+ switch (event) {
+ case NETDEV_UNREGISTER:
+ sock = dev->mp_port->sock;
+ mp = container_of(sock->sk, struct mp_sock, sk)->mp;
+ do_unbind(mp->mfile);
+ break;
+ case NETDEV_CHANGE:
+ sk = dev->mp_port->sock->sk;
+ sk->sk_state_change(sk);
+ break;
+ }
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block mp_notifier_block __read_mostly = {
+ .notifier_call = mp_device_event,
+};
+
+static int mp_init(void)
+{
+ int err = 0;
+
+ ext_page_info_cache = kmem_cache_create("skb_page_info",
+ sizeof(struct page_info),
+ 0, SLAB_HWCACHE_ALIGN, NULL);
+ if (!ext_page_info_cache)
+ return -ENOMEM;
+
+ err = misc_register(&mp_miscdev);
+ if (err) {
+ printk(KERN_ERR "mp: Can't register misc device\n");
+ kmem_cache_destroy(ext_page_info_cache);
+ } else {
+ printk(KERN_INFO "Registering mp misc device - minor = %d\n",
+ mp_miscdev.minor);
+ register_netdevice_notifier(&mp_notifier_block);
+ }
+ return err;
+}
+
+void mp_exit(void)
+{
+ unregister_netdevice_notifier(&mp_notifier_block);
+ misc_deregister(&mp_miscdev);
+ kmem_cache_destroy(ext_page_info_cache);
+}
+
+/* Get an underlying socket object from mp file. Returns error unless file is
+ * attached to a device. The returned object works like a packet socket, it
+ * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
+ * holding a reference to the file for as long as the socket is in use. */
+struct socket *mp_get_socket(struct file *file)
+{
+ struct mp_file *mfile = file->private_data;
+ struct mp_struct *mp;
+
+ if (file->f_op != &mp_fops)
+ return ERR_PTR(-EINVAL);
+ mp = mp_get(mfile);
+ if (!mp)
+ return ERR_PTR(-EBADFD);
+ mp_put(mfile);
+ return &mp->socket;
+}
+EXPORT_SYMBOL_GPL(mp_get_socket);
+
+module_init(mp_init);
+module_exit(mp_exit);
+MODULE_AUTHOR(DRV_COPYRIGHT);
+MODULE_DESCRIPTION(DRV_DESCRIPTION);
+MODULE_LICENSE("GPL v2");
--
1.5.4.4


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  Last update: 2010-08-06 11:13    [from the cache]
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