Allow the guest to reuse the hash value to make receive steering consistent between the host and guest, and to save hash computation.
Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com --- Documentation/networking/tuntap.rst | 7 +++ drivers/net/Kconfig | 1 + drivers/net/tun.c | 117 +++++++++++++++++++++++++++++++----- include/uapi/linux/if_tun.h | 44 ++++++++++++++ 4 files changed, 155 insertions(+), 14 deletions(-)
diff --git a/Documentation/networking/tuntap.rst b/Documentation/networking/tuntap.rst index 4d7087f727be..86b4ae8caa8a 100644 --- a/Documentation/networking/tuntap.rst +++ b/Documentation/networking/tuntap.rst @@ -206,6 +206,13 @@ enable is true we enable it, otherwise we disable it:: return ioctl(fd, TUNSETQUEUE, (void *)&ifr); }
+3.4 Reference +------------- + +``linux/if_tun.h`` defines the interface described below: + +.. kernel-doc:: include/uapi/linux/if_tun.h + Universal TUN/TAP device driver Frequently Asked Question =========================================================
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index 9920b3a68ed1..e2a7bd703550 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -395,6 +395,7 @@ config TUN tristate "Universal TUN/TAP device driver support" depends on INET select CRC32 + select SKB_EXTENSIONS help TUN/TAP provides packet reception and transmission for user space programs. It can be viewed as a simple Point-to-Point or Ethernet diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 9d93ab9ee58f..986e4a5bf04d 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -173,6 +173,10 @@ struct tun_prog { struct bpf_prog *prog; };
+struct tun_vnet_hash_container { + struct tun_vnet_hash common; +}; + /* Since the socket were moved to tun_file, to preserve the behavior of persist * device, socket filter, sndbuf and vnet header size were restore when the * file were attached to a persist device. @@ -210,6 +214,7 @@ struct tun_struct { struct bpf_prog __rcu *xdp_prog; struct tun_prog __rcu *steering_prog; struct tun_prog __rcu *filter_prog; + struct tun_vnet_hash vnet_hash; struct ethtool_link_ksettings link_ksettings; /* init args */ struct file *file; @@ -221,6 +226,11 @@ struct veth { __be16 h_vlan_TCI; };
+static const struct tun_vnet_hash tun_vnet_hash_cap = { + .flags = TUN_VNET_HASH_REPORT, + .types = VIRTIO_NET_SUPPORTED_HASH_TYPES +}; + static void tun_flow_init(struct tun_struct *tun); static void tun_flow_uninit(struct tun_struct *tun);
@@ -322,10 +332,15 @@ static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp) if (get_user(be, argp)) return -EFAULT;
- if (be) + if (be) { + if (!(tun->flags & TUN_VNET_LE) && + (tun->vnet_hash.flags & TUN_VNET_HASH_REPORT)) + return -EBUSY; + tun->flags |= TUN_VNET_BE; - else + } else { tun->flags &= ~TUN_VNET_BE; + }
return 0; } @@ -524,12 +539,17 @@ static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) */ static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb) { + struct tun_vnet_hash_ext *ext; + struct flow_keys keys; struct tun_flow_entry *e; u32 txq, numqueues;
numqueues = READ_ONCE(tun->numqueues);
- txq = __skb_get_hash_symmetric(skb); + memset(&keys, 0, sizeof(keys)); + skb_flow_dissect(skb, &flow_keys_dissector_symmetric, &keys, 0); + + txq = flow_hash_from_keys(&keys); e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); if (e) { tun_flow_save_rps_rxhash(e, txq); @@ -538,6 +558,16 @@ static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb) txq = reciprocal_scale(txq, numqueues); }
+ if (tun->vnet_hash.flags & TUN_VNET_HASH_REPORT) { + ext = skb_ext_add(skb, SKB_EXT_TUN_VNET_HASH); + if (ext) { + u32 types = tun->vnet_hash.types; + + ext->report = virtio_net_hash_report(types, keys.basic); + ext->value = skb->l4_hash ? skb->hash : txq; + } + } + return txq; }
@@ -2120,33 +2150,58 @@ static ssize_t tun_put_user(struct tun_struct *tun, }
if (vnet_hdr_sz) { - struct virtio_net_hdr gso; + struct tun_vnet_hash_ext *ext; + size_t vnet_hdr_content_sz = sizeof(struct virtio_net_hdr); + union { + struct virtio_net_hdr hdr; + struct virtio_net_hdr_v1_hash hdr_v1_hash; + } vnet_hdr; + int ret;
if (iov_iter_count(iter) < vnet_hdr_sz) return -EINVAL;
- if (virtio_net_hdr_from_skb(skb, &gso, - tun_is_little_endian(tun), true, - vlan_hlen)) { + ext = vnet_hdr_sz < sizeof(vnet_hdr.hdr_v1_hash) ? + NULL : skb_ext_find(skb, SKB_EXT_TUN_VNET_HASH); + + if (ext) { + vnet_hdr_content_sz = sizeof(vnet_hdr.hdr_v1_hash); + memset(&vnet_hdr, 0, vnet_hdr_content_sz); + vnet_hdr.hdr_v1_hash.hdr.num_buffers = __cpu_to_virtio16(true, 1); + vnet_hdr.hdr_v1_hash.hash_value = cpu_to_le32(ext->value); + vnet_hdr.hdr_v1_hash.hash_report = cpu_to_le16(ext->report); + } else { + vnet_hdr_content_sz = sizeof(struct virtio_net_hdr); + } + + ret = virtio_net_hdr_from_skb(skb, + &vnet_hdr.hdr, + tun_is_little_endian(tun), + true, + vlan_hlen); + + if (ret) { struct skb_shared_info *sinfo = skb_shinfo(skb);
if (net_ratelimit()) { netdev_err(tun->dev, "unexpected GSO type: 0x%x, gso_size %d, hdr_len %d\n", - sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size), - tun16_to_cpu(tun, gso.hdr_len)); + sinfo->gso_type, + tun16_to_cpu(tun, vnet_hdr.hdr.gso_size), + tun16_to_cpu(tun, vnet_hdr.hdr.hdr_len)); print_hex_dump(KERN_ERR, "tun: ", DUMP_PREFIX_NONE, 16, 1, skb->head, - min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true); + min(tun16_to_cpu(tun, vnet_hdr.hdr.hdr_len), 64), + true); } WARN_ON_ONCE(1); return -EINVAL; }
- if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso)) + if (copy_to_iter(&vnet_hdr, vnet_hdr_content_sz, iter) != vnet_hdr_content_sz) return -EFAULT;
- iov_iter_zero(vnet_hdr_sz - sizeof(gso), iter); + iov_iter_zero(vnet_hdr_sz - vnet_hdr_content_sz, iter); }
if (vlan_hlen) { @@ -3094,6 +3149,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, int le; int ret; bool do_notify = false; + struct tun_vnet_hash vnet_hash;
if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) { @@ -3115,6 +3171,9 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) return -EPERM; return open_related_ns(&net->ns, get_net_ns); + } else if (cmd == TUNGETVNETHASHCAP) { + return copy_to_user(argp, &tun_vnet_hash_cap, sizeof(tun_vnet_hash_cap)) ? + -EFAULT : 0; }
rtnl_lock(); @@ -3314,6 +3373,12 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, break; }
+ if (tun->vnet_hash.flags & TUN_VNET_HASH_REPORT && + vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr_v1_hash)) { + ret = -EBUSY; + break; + } + tun->vnet_hdr_sz = vnet_hdr_sz; break;
@@ -3328,10 +3393,17 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, ret = -EFAULT; break; } - if (le) + if (le) { tun->flags |= TUN_VNET_LE; - else + } else { + if (tun->vnet_hash.flags & TUN_VNET_HASH_REPORT && + !tun_legacy_is_little_endian(tun)) { + ret = -EBUSY; + break; + } + tun->flags &= ~TUN_VNET_LE; + } break;
case TUNGETVNETBE: @@ -3396,6 +3468,23 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, ret = open_related_ns(&net->ns, get_net_ns); break;
+ case TUNSETVNETHASH: + if (copy_from_user(&vnet_hash, argp, sizeof(vnet_hash))) { + ret = -EFAULT; + break; + } + argp = (struct tun_vnet_hash __user *)argp + 1; + + if ((vnet_hash.flags & TUN_VNET_HASH_REPORT) && + (tun->vnet_hdr_sz < sizeof(struct virtio_net_hdr_v1_hash) || + !tun_is_little_endian(tun))) { + ret = -EBUSY; + break; + } + + tun->vnet_hash = vnet_hash; + break; + default: ret = -EINVAL; break; diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h index 287cdc81c939..1561e8ce0a0a 100644 --- a/include/uapi/linux/if_tun.h +++ b/include/uapi/linux/if_tun.h @@ -62,6 +62,30 @@ #define TUNSETCARRIER _IOW('T', 226, int) #define TUNGETDEVNETNS _IO('T', 227)
+/** + * define TUNGETVNETHASHCAP - ioctl to get virtio_net hashing capability. + * + * The argument is a pointer to &struct tun_vnet_hash which will store the + * maximal virtio_net hashing configuration. + */ +#define TUNGETVNETHASHCAP _IOR('T', 228, struct tun_vnet_hash) + +/** + * define TUNSETVNETHASH - ioctl to configure virtio_net hashing + * + * The argument is a pointer to &struct tun_vnet_hash. + * + * %TUNSETVNETHDRSZ ioctl must be called with a number greater than or equal to + * the size of &struct virtio_net_hdr_v1_hash before calling this ioctl with + * %TUN_VNET_HASH_REPORT. + * + * The virtio_net header must be configured as little-endian before calling this + * ioctl with %TUN_VNET_HASH_REPORT. + * + * This ioctl currently has no effect on XDP packets. + */ +#define TUNSETVNETHASH _IOW('T', 229, struct tun_vnet_hash) + /* TUNSETIFF ifr flags */ #define IFF_TUN 0x0001 #define IFF_TAP 0x0002 @@ -115,4 +139,24 @@ struct tun_filter { __u8 addr[][ETH_ALEN]; };
+/** + * define TUN_VNET_HASH_REPORT - Request virtio_net hash reporting for vhost + */ +#define TUN_VNET_HASH_REPORT 0x0001 + +/** + * struct tun_vnet_hash - virtio_net hashing configuration + * @flags: + * Bitmask consists of %TUN_VNET_HASH_REPORT and %TUN_VNET_HASH_RSS + * @pad: + * Should be filled with zero before passing to %TUNSETVNETHASH + * @types: + * Bitmask of allowed hash types + */ +struct tun_vnet_hash { + __u16 flags; + __u8 pad[2]; + __u32 types; +}; + #endif /* _UAPI__IF_TUN_H */