This patch adds a simple flow director to tun/tap device. It is just a page that contains the hash to queue mapping which could be changed by user-space. The backend (tap/macvtap) would query this table to get the desired queue of a packets when it send packets to userspace.
The page address were set through a new kind of ioctl - TUNSETFD and were pinned until device exit or another new page were specified. Signed-off-by: Jason Wang <[email protected]> --- drivers/net/tun.c | 63 ++++++++++++++++++++++++++++++++++++++++-------- include/linux/if_tun.h | 10 ++++++++ 2 files changed, 62 insertions(+), 11 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 7d22b4b..2efaf81 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -64,6 +64,7 @@ #include <linux/nsproxy.h> #include <linux/virtio_net.h> #include <linux/rcupdate.h> +#include <linux/highmem.h> #include <net/net_namespace.h> #include <net/netns/generic.h> #include <net/rtnetlink.h> @@ -109,6 +110,7 @@ struct tap_filter { }; #define MAX_TAP_QUEUES (NR_CPUS < 16 ? NR_CPUS : 16) +#define TAP_HASH_MASK 0xFF struct tun_file { struct sock sk; @@ -128,6 +130,7 @@ struct tun_sock; struct tun_struct { struct tun_file *tfiles[MAX_TAP_QUEUES]; + struct page *fd_page[1]; unsigned int numqueues; unsigned int flags; uid_t owner; @@ -156,7 +159,7 @@ static struct tun_file *tun_get_queue(struct net_device *dev, struct tun_struct *tun = netdev_priv(dev); struct tun_file *tfile = NULL; int numqueues = tun->numqueues; - __u32 rxq; + __u32 rxq, rxhash; BUG_ON(!rcu_read_lock_held()); @@ -168,6 +171,22 @@ static struct tun_file *tun_get_queue(struct net_device *dev, goto out; } + rxhash = skb_get_rxhash(skb); + if (rxhash) { + if (tun->fd_page[0]) { + u16 *table = kmap_atomic(tun->fd_page[0]); + rxq = table[rxhash & TAP_HASH_MASK]; + kunmap_atomic(table); + if (rxq < numqueues) { + tfile = rcu_dereference(tun->tfiles[rxq]); + goto out; + } + } + rxq = ((u64)rxhash * numqueues) >> 32; + tfile = rcu_dereference(tun->tfiles[rxq]); + goto out; + } + if (likely(skb_rx_queue_recorded(skb))) { rxq = skb_get_rx_queue(skb); @@ -178,14 +197,6 @@ static struct tun_file *tun_get_queue(struct net_device *dev, goto out; } - /* Check if we can use flow to select a queue */ - rxq = skb_get_rxhash(skb); - if (rxq) { - u32 idx = ((u64)rxq * numqueues) >> 32; - tfile = rcu_dereference(tun->tfiles[idx]); - goto out; - } - tfile = rcu_dereference(tun->tfiles[0]); out: return tfile; @@ -1020,6 +1031,14 @@ out: return ret; } +static void tun_destructor(struct net_device *dev) +{ + struct tun_struct *tun = netdev_priv(dev); + if (tun->fd_page[0]) + put_page(tun->fd_page[0]); + free_netdev(dev); +} + static void tun_setup(struct net_device *dev) { struct tun_struct *tun = netdev_priv(dev); @@ -1028,7 +1047,7 @@ static void tun_setup(struct net_device *dev) tun->group = -1; dev->ethtool_ops = &tun_ethtool_ops; - dev->destructor = free_netdev; + dev->destructor = tun_destructor; } /* Trivial set of netlink ops to allow deleting tun or tap @@ -1230,6 +1249,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) tun = netdev_priv(dev); tun->dev = dev; tun->flags = flags; + tun->fd_page[0] = NULL; security_tun_dev_post_create(&tfile->sk); @@ -1353,6 +1373,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, struct net_device *dev = NULL; void __user* argp = (void __user*)arg; struct ifreq ifr; + struct tun_fd tfd; int ret; if (cmd == TUNSETIFF || cmd == TUNATTACHQUEUE || _IOC_TYPE(cmd) == 0x89) @@ -1364,7 +1385,8 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, * This is needed because we never checked for invalid flags on * TUNSETIFF. */ return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | - IFF_VNET_HDR | IFF_MULTI_QUEUE | IFF_RXHASH, + IFF_VNET_HDR | IFF_MULTI_QUEUE | IFF_RXHASH | + IFF_FD, (unsigned int __user*)argp); } @@ -1476,6 +1498,25 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, ret = set_offload(tun, arg); break; + case TUNSETFD: + if (copy_from_user(&tfd, argp, sizeof(tfd))) + ret = -EFAULT; + else { + if (tun->fd_page[0]) { + put_page(tun->fd_page[0]); + tun->fd_page[0] = NULL; + } + + /* put_page() in tun_destructor() */ + if (get_user_pages_fast(tfd.addr, 1, 0, + &tun->fd_page[0]) != 1) + ret = -EFAULT; + else + ret = 0; + } + + break; + case SIOCGIFHWADDR: /* Get hw address */ memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h index a1f6f3f..726731d 100644 --- a/include/linux/if_tun.h +++ b/include/linux/if_tun.h @@ -36,6 +36,8 @@ #define TUN_VNET_HDR 0x0200 #define TUN_TAP_MQ 0x0400 +struct tun_fd; + /* Ioctl defines */ #define TUNSETNOCSUM _IOW('T', 200, int) #define TUNSETDEBUG _IOW('T', 201, int) @@ -56,6 +58,7 @@ #define TUNSETVNETHDRSZ _IOW('T', 216, int) #define TUNATTACHQUEUE _IOW('T', 217, int) #define TUNDETACHQUEUE _IOW('T', 218, int) +#define TUNSETFD _IOW('T', 219, struct tun_fd) /* TUNSETIFF ifr flags */ @@ -67,6 +70,7 @@ #define IFF_TUN_EXCL 0x8000 #define IFF_MULTI_QUEUE 0x0100 #define IFF_RXHASH 0x0200 +#define IFF_FD 0x0400 /* Features for GSO (TUNSETOFFLOAD). */ #define TUN_F_CSUM 0x01 /* You can hand me unchecksummed packets. */ @@ -97,6 +101,12 @@ struct tun_filter { __u8 addr[0][ETH_ALEN]; }; +/* Programmable flow director */ +struct tun_fd { + unsigned long addr; + size_t size; +}; + #ifdef __KERNEL__ #if defined(CONFIG_TUN) || defined(CONFIG_TUN_MODULE) struct socket *tun_get_socket(struct file *); _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
