From f43798c27684ab925adde7d8acc34c78c6e50df8 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 3 Jul 2008 03:48:02 -0700 Subject: [PATCH] tun: Allow GSO using virtio_net_hdr Add a IFF_VNET_HDR flag. This uses the same ABI as virtio_net (ie. prepending struct virtio_net_hdr to packets) to indicate GSO and checksum information. Signed-off-by: Rusty Russell Acked-by: Max Krasnyansky Signed-off-by: David S. Miller --- drivers/net/tun.c | 95 ++++++++++++++++++++++++++++++++++++++++-- include/linux/if_tun.h | 2 + 2 files changed, 94 insertions(+), 3 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index a314955e699..aa4ee4439f0 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -63,6 +63,7 @@ #include #include #include +#include #include #include @@ -283,6 +284,7 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) }; struct sk_buff *skb; size_t len = count, align = 0; + struct virtio_net_hdr gso = { 0 }; if (!(tun->flags & TUN_NO_PI)) { if ((len -= sizeof(pi)) > count) @@ -292,6 +294,17 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, return -EFAULT; } + if (tun->flags & TUN_VNET_HDR) { + if ((len -= sizeof(gso)) > count) + return -EINVAL; + + if (memcpy_fromiovec((void *)&gso, iv, sizeof(gso))) + return -EFAULT; + + if (gso.hdr_len > len) + return -EINVAL; + } + if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { align = NET_IP_ALIGN; if (unlikely(len < ETH_HLEN)) @@ -311,6 +324,16 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, return -EFAULT; } + if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { + if (!skb_partial_csum_set(skb, gso.csum_start, + gso.csum_offset)) { + tun->dev->stats.rx_frame_errors++; + kfree_skb(skb); + return -EINVAL; + } + } else if (tun->flags & TUN_NOCHECKSUM) + skb->ip_summed = CHECKSUM_UNNECESSARY; + switch (tun->flags & TUN_TYPE_MASK) { case TUN_TUN_DEV: if (tun->flags & TUN_NO_PI) { @@ -337,8 +360,35 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, break; }; - if (tun->flags & TUN_NOCHECKSUM) - skb->ip_summed = CHECKSUM_UNNECESSARY; + if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { + pr_debug("GSO!\n"); + switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { + case VIRTIO_NET_HDR_GSO_TCPV4: + skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; + break; + case VIRTIO_NET_HDR_GSO_TCPV6: + skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; + break; + default: + tun->dev->stats.rx_frame_errors++; + kfree_skb(skb); + return -EINVAL; + } + + if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) + skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; + + skb_shinfo(skb)->gso_size = gso.gso_size; + if (skb_shinfo(skb)->gso_size == 0) { + tun->dev->stats.rx_frame_errors++; + kfree_skb(skb); + return -EINVAL; + } + + /* Header must be checked, and gso_segs computed. */ + skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; + skb_shinfo(skb)->gso_segs = 0; + } netif_rx_ni(skb); tun->dev->last_rx = jiffies; @@ -384,6 +434,39 @@ static __inline__ ssize_t tun_put_user(struct tun_struct *tun, total += sizeof(pi); } + if (tun->flags & TUN_VNET_HDR) { + struct virtio_net_hdr gso = { 0 }; /* no info leak */ + if ((len -= sizeof(gso)) < 0) + return -EINVAL; + + if (skb_is_gso(skb)) { + struct skb_shared_info *sinfo = skb_shinfo(skb); + + /* This is a hint as to how much should be linear. */ + gso.hdr_len = skb_headlen(skb); + gso.gso_size = sinfo->gso_size; + if (sinfo->gso_type & SKB_GSO_TCPV4) + gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; + else if (sinfo->gso_type & SKB_GSO_TCPV6) + gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; + else + BUG(); + if (sinfo->gso_type & SKB_GSO_TCP_ECN) + gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; + } else + gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; + + if (skb->ip_summed == CHECKSUM_PARTIAL) { + gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; + gso.csum_start = skb->csum_start - skb_headroom(skb); + gso.csum_offset = skb->csum_offset; + } /* else everything is zero */ + + if (unlikely(memcpy_toiovec(iv, (void *)&gso, sizeof(gso)))) + return -EFAULT; + total += sizeof(gso); + } + len = min_t(int, skb->len, len); skb_copy_datagram_iovec(skb, 0, iv, len); @@ -598,6 +681,11 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) else tun->flags &= ~TUN_ONE_QUEUE; + if (ifr->ifr_flags & IFF_VNET_HDR) + tun->flags |= TUN_VNET_HDR; + else + tun->flags &= ~TUN_VNET_HDR; + file->private_data = tun; tun->attached = 1; get_net(dev_net(tun->dev)); @@ -684,7 +772,8 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file, /* Currently this just means: "what IFF flags are valid?". * 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, + return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | + IFF_VNET_HDR, (unsigned int __user*)argp); } diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h index 3f0a0995d44..563fae542da 100644 --- a/include/linux/if_tun.h +++ b/include/linux/if_tun.h @@ -31,6 +31,7 @@ #define TUN_NO_PI 0x0040 #define TUN_ONE_QUEUE 0x0080 #define TUN_PERSIST 0x0100 +#define TUN_VNET_HDR 0x0200 /* Ioctl defines */ #define TUNSETNOCSUM _IOW('T', 200, int) @@ -48,6 +49,7 @@ #define IFF_TAP 0x0002 #define IFF_NO_PI 0x1000 #define IFF_ONE_QUEUE 0x2000 +#define IFF_VNET_HDR 0x4000 /* Features for GSO (TUNSETOFFLOAD). */ #define TUN_F_CSUM 0x01 /* You can hand me unchecksummed packets. */ -- 2.41.1