| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <1d1e680a-fc27-48b9-973b-408c5c7c1342@daynix.com>
Date: Sat, 12 Oct 2024 19:13:05 +0900
From: Akihiko Odaki <akihiko.odaki@...nix.com>
To: Jason Wang <jasowang@...hat.com>
Cc: Jonathan Corbet <corbet@....net>,
Willem de Bruijn <willemdebruijn.kernel@...il.com>,
"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
"Michael S. Tsirkin" <mst@...hat.com>, Xuan Zhuo
<xuanzhuo@...ux.alibaba.com>, Shuah Khan <shuah@...nel.org>,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
netdev@...r.kernel.org, kvm@...r.kernel.org,
virtualization@...ts.linux-foundation.org, linux-kselftest@...r.kernel.org,
Yuri Benditovich <yuri.benditovich@...nix.com>,
Andrew Melnychenko <andrew@...nix.com>,
Stephen Hemminger <stephen@...workplumber.org>, gur.stavi@...wei.com
Subject: Re: [PATCH RFC v5 06/10] tun: Introduce virtio-net hash reporting
feature
On 2024/10/09 17:05, Jason Wang wrote:
> On Tue, Oct 8, 2024 at 2:55 PM Akihiko Odaki <akihiko.odaki@...nix.com> wrote:
>>
>> 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@...nix.com>
>
> I wonder if this would cause overhead when hash reporting is not enabled?
It only adds two branches in the data path. The first one is in
tun_vnet_hash_report(), which determines to add the hash value to
sk_buff. The second one is in tun_vnet_hdr_from_skb(), which determines
to report the added hash value.
>
>> ---
>> Documentation/networking/tuntap.rst | 7 +++
>> drivers/net/Kconfig | 1 +
>> drivers/net/tap.c | 45 ++++++++++++++--
>
> Tile should be for tap as well or is this just for tun?
It is also for tap. I will update the title in v6.
>
>> drivers/net/tun.c | 46 ++++++++++++----
>> drivers/net/tun_vnet.h | 102 +++++++++++++++++++++++++++++++-----
>> include/linux/if_tap.h | 2 +
>> include/uapi/linux/if_tun.h | 48 +++++++++++++++++
>> 7 files changed, 223 insertions(+), 28 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
>
> Then we need this for macvtap at least as well?
>
>> 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/tap.c b/drivers/net/tap.c
>> index 9a34ceed0c2c..5e2fbe63ca47 100644
>> --- a/drivers/net/tap.c
>> +++ b/drivers/net/tap.c
>> @@ -179,6 +179,16 @@ static void tap_put_queue(struct tap_queue *q)
>> sock_put(&q->sk);
>> }
>>
>> +static struct virtio_net_hash *tap_add_hash(struct sk_buff *skb)
>> +{
>> + return (struct virtio_net_hash *)skb->cb;
>
> Any reason that tap uses skb->cb but not skb extensions? (And is it
> safe to use that without cloning?)
tun adds virtio_net_hash to a skb in ndo_select_queue(), but it does not
immediately put it into its ptr_ring; instead ndo_start_xmit() does so.
It is hard to ensure that nobody modifies skb->cb between the two calls.
The situation is different for tap. tap_handle_frame() adds
virtio_net_hash to a skb and immediately adds it in its ptr_ring so
nobody should touch it between that.
>
>> +}
>> +
>> +static const struct virtio_net_hash *tap_find_hash(const struct sk_buff *skb)
>> +{
>> + return (const struct virtio_net_hash *)skb->cb;
>> +}
>> +
>> /*
>> * Select a queue based on the rxq of the device on which this packet
>> * arrived. If the incoming device is not mq, calculate a flow hash
>> @@ -189,6 +199,7 @@ static void tap_put_queue(struct tap_queue *q)
>> static struct tap_queue *tap_get_queue(struct tap_dev *tap,
>> struct sk_buff *skb)
>> {
>> + struct flow_keys_basic keys_basic;
>> struct tap_queue *queue = NULL;
>> /* Access to taps array is protected by rcu, but access to numvtaps
>> * isn't. Below we use it to lookup a queue, but treat it as a hint
>> @@ -198,15 +209,32 @@ static struct tap_queue *tap_get_queue(struct tap_dev *tap,
>> int numvtaps = READ_ONCE(tap->numvtaps);
>> __u32 rxq;
>>
>> + *tap_add_hash(skb) = (struct virtio_net_hash) { .report = VIRTIO_NET_HASH_REPORT_NONE };
>> +
>> if (!numvtaps)
>> goto out;
>>
>> if (numvtaps == 1)
>> goto single;
>>
>> + if (!skb->l4_hash && !skb->sw_hash) {
>> + struct flow_keys keys;
>> +
>> + skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
>> + rxq = flow_hash_from_keys(&keys);
>> + keys_basic = (struct flow_keys_basic) {
>> + .control = keys.control,
>> + .basic = keys.basic
>> + };
>> + } else {
>> + skb_flow_dissect_flow_keys_basic(NULL, skb, &keys_basic, NULL, 0, 0, 0,
>> + FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
>> + rxq = skb->hash;
>> + }
>> +
>> /* Check if we can use flow to select a queue */
>> - rxq = skb_get_hash(skb);
>> if (rxq) {
>> + tun_vnet_hash_report(&tap->vnet_hash, skb, &keys_basic, rxq, tap_add_hash);
>> queue = rcu_dereference(tap->taps[rxq % numvtaps]);
>> goto out;
>> }
>> @@ -713,15 +741,16 @@ static ssize_t tap_put_user(struct tap_queue *q,
>> int total;
>>
>> if (q->flags & IFF_VNET_HDR) {
>> - struct virtio_net_hdr vnet_hdr;
>> + struct virtio_net_hdr_v1_hash vnet_hdr;
>>
>> vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
>>
>> - ret = tun_vnet_hdr_from_skb(q->flags, NULL, skb, &vnet_hdr);
>> + ret = tun_vnet_hdr_from_skb(vnet_hdr_len, q->flags, NULL, skb,
>> + tap_find_hash, &vnet_hdr);
>> if (ret < 0)
>> goto done;
>>
>> - ret = tun_vnet_hdr_put(vnet_hdr_len, iter, &vnet_hdr);
>> + ret = tun_vnet_hdr_put(vnet_hdr_len, iter, &vnet_hdr, ret);
>> if (ret < 0)
>> goto done;
>> }
>> @@ -1025,7 +1054,13 @@ static long tap_ioctl(struct file *file, unsigned int cmd,
>> return ret;
>>
>> default:
>> - return tun_vnet_ioctl(&q->vnet_hdr_sz, &q->flags, cmd, sp);
>> + rtnl_lock();
>> + tap = rtnl_dereference(q->tap);
>> + ret = tun_vnet_ioctl(&q->vnet_hdr_sz, &q->flags,
>> + tap ? &tap->vnet_hash : NULL, -EINVAL,
>> + cmd, sp);
>> + rtnl_unlock();
>> + return ret;
>> }
>> }
>>
>> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
>> index dd8799d19518..27308417b834 100644
>> --- a/drivers/net/tun.c
>> +++ b/drivers/net/tun.c
>> @@ -209,6 +209,7 @@ 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;
>> @@ -451,6 +452,16 @@ static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
>> e->rps_rxhash = hash;
>> }
>>
>> +static struct virtio_net_hash *tun_add_hash(struct sk_buff *skb)
>> +{
>> + return skb_ext_add(skb, SKB_EXT_TUN_VNET_HASH);
>> +}
>> +
>> +static const struct virtio_net_hash *tun_find_hash(const struct sk_buff *skb)
>> +{
>> + return skb_ext_find(skb, SKB_EXT_TUN_VNET_HASH);
>> +}
>> +
>> /* We try to identify a flow through its rxhash. The reason that
>> * we do not check rxq no. is because some cards(e.g 82599), chooses
>> * the rxq based on the txq where the last packet of the flow comes. As
>> @@ -459,12 +470,17 @@ 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 flow_keys keys;
>> + struct flow_keys_basic keys_basic;
>> 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);
>> @@ -473,6 +489,13 @@ static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
>> txq = reciprocal_scale(txq, numqueues);
>> }
>>
>> + keys_basic = (struct flow_keys_basic) {
>> + .control = keys.control,
>> + .basic = keys.basic
>> + };
>> + tun_vnet_hash_report(&tun->vnet_hash, skb, &keys_basic, skb->l4_hash ? skb->hash : txq,
>> + tun_add_hash);
>
> Is using txq required when not l4_hash is required by the virtio-spec?
It is a limitation of the implementation. A hardware driver may set a
hash value with skb_set_hash(), which takes enum pkt_hash_types. The
enum is defined as follows:
enum pkt_hash_types {
PKT_HASH_TYPE_NONE, /* Undefined type */
PKT_HASH_TYPE_L2, /* Input: src_MAC, dest_MAC */
PKT_HASH_TYPE_L3, /* Input: src_IP, dst_IP */
PKT_HASH_TYPE_L4, /* Input: src_IP, dst_IP, src_port, dst_port */
};
A hash value with PKT_HASH_TYPE_L2 must be ignored as the virtio spec
does not have a corresponding hash type. The virtio spec has
corresponding hash types for PKT_HASH_TYPE_L3 and PKT_HASH_TYPE_L4 so we
should report them with the virtio_net header.
However, skb only tells whether the hash is PKT_HASH_TYPE_L4 or not. So
tun reports skb->hash with a L4 hash type if the hash is
PKT_HASH_TYPE_L4. Otherwise it ignores skb->hash and uses the hash value
computed its own because it cannot tell if skb->hash is PKT_HASH_TYPE_L2
or PKT_HASH_TYPE_L3.
>
>> +
>> return txq;
>> }
>>
>> @@ -1990,10 +2013,8 @@ static ssize_t tun_put_user_xdp(struct tun_struct *tun,
>> size_t total;
>>
>> if (tun->flags & IFF_VNET_HDR) {
>> - struct virtio_net_hdr gso = { 0 };
>> -
>> vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
>> - ret = tun_vnet_hdr_put(vnet_hdr_sz, iter, &gso);
>> + ret = tun_vnet_hdr_put(vnet_hdr_sz, iter, NULL, 0);
>> if (ret < 0)
>> return ret;
>> }
>> @@ -2018,7 +2039,6 @@ static ssize_t tun_put_user(struct tun_struct *tun,
>> int vlan_offset = 0;
>> int vlan_hlen = 0;
>> int vnet_hdr_sz = 0;
>> - int ret;
>>
>> if (skb_vlan_tag_present(skb))
>> vlan_hlen = VLAN_HLEN;
>> @@ -2043,13 +2063,15 @@ static ssize_t tun_put_user(struct tun_struct *tun,
>> }
>>
>> if (vnet_hdr_sz) {
>> - struct virtio_net_hdr gso;
>> + struct virtio_net_hdr_v1_hash gso;
>> + int ret;
>>
>> - ret = tun_vnet_hdr_from_skb(tun->flags, tun->dev, skb, &gso);
>> + ret = tun_vnet_hdr_from_skb(vnet_hdr_sz, tun->flags, tun->dev, skb,
>> + tun_find_hash, &gso);
>> if (ret < 0)
>> goto done;
>>
>> - ret = tun_vnet_hdr_put(vnet_hdr_sz, iter, &gso);
>> + ret = tun_vnet_hdr_put(vnet_hdr_sz, iter, &gso, ret);
>> if (ret < 0)
>> goto done;
>> }
>> @@ -3055,9 +3077,10 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
>> goto unlock;
>> }
>>
>> - ret = -EBADFD;
>> - if (!tun)
>> + if (!tun) {
>> + ret = tun_vnet_ioctl(NULL, NULL, NULL, -EBADFD, cmd, argp);
>
> This seems not elegant (passing three NULL pointers). Any reason we
> can't just modify __tun_chr_ioctl() instead of introducing things like
> tun_vnet_ioctl()?
tun_vnet_ioctl() is introduced with patch "tun: Unify vnet
implementation". We can abandon unifying the ioctl handling if the
interface looks too awkward.
>
>> goto unlock;
>> + }
>>
>> netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd);
>>
>> @@ -3256,7 +3279,8 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
>> break;
>>
>> default:
>> - ret = tun_vnet_ioctl(&tun->vnet_hdr_sz, &tun->flags, cmd, argp);
>> + ret = tun_vnet_ioctl(&tun->vnet_hdr_sz, &tun->flags,
>> + &tun->vnet_hash, -EINVAL, cmd, argp);
>> }
>>
>> if (do_notify)
>> diff --git a/drivers/net/tun_vnet.h b/drivers/net/tun_vnet.h
>> index c40bde0fdf8c..589a97dd7d02 100644
>> --- a/drivers/net/tun_vnet.h
>> +++ b/drivers/net/tun_vnet.h
>> @@ -6,6 +6,9 @@
>> #define TUN_VNET_LE 0x80000000
>> #define TUN_VNET_BE 0x40000000
>>
>> +typedef struct virtio_net_hash *(*tun_vnet_hash_add)(struct sk_buff *);
>> +typedef const struct virtio_net_hash *(*tun_vnet_hash_find)(const struct sk_buff *);
>> +
>> static inline bool tun_vnet_legacy_is_little_endian(unsigned int flags)
>> {
>> return !(IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) && (flags & TUN_VNET_BE)) &&
>> @@ -59,18 +62,31 @@ static inline __virtio16 cpu_to_tun_vnet16(unsigned int flags, u16 val)
>> }
>>
>> static inline long tun_vnet_ioctl(int *sz, unsigned int *flags,
>> - unsigned int cmd, int __user *sp)
>> + struct tun_vnet_hash *hash, long fallback,
>> + unsigned int cmd, void __user *argp)
>> {
>> + static const struct tun_vnet_hash cap = {
>> + .flags = TUN_VNET_HASH_REPORT,
>> + .types = VIRTIO_NET_SUPPORTED_HASH_TYPES
>> + };
>
> Let's find a way to reuse virtio-net uAPI instead of introducing new
> stuff to stress the management layer.
I found include/uapi/linux/virtio_net.h inappropriate for this ioctl.
It has the following structure for hash reporting:
struct virtio_net_hash_config {
__le32 hash_types;
/* for compatibility with virtio_net_rss_config */
__le16 reserved[4];
__u8 hash_key_length;
__u8 hash_key_data[/* hash_key_length */];
};
We do not care hash_key_length and hash_key_data.
It has the following structure for RSS and hash reporting when RSS is
enabled:
struct virtio_net_rss_config {
__le32 hash_types;
__le16 indirection_table_mask;
__le16 unclassified_queue;
__le16 indirection_table[1/* + indirection_table_mask */];
__le16 max_tx_vq;
__u8 hash_key_length;
__u8 hash_key_data[/* hash_key_length */];
};
This structure is hard to use as it has data members after the
indirection_table flexible array. max_tx_vq is not our interest either.
I tested the usability of ioctl by actually using it in QEMU. The RFC
patch series is available at:
https://patchew.org/QEMU/20240915-hash-v3-0-79cb08d28647@daynix.com/
>
>> + struct tun_vnet_hash hash_buf;
>> + int __user *sp = argp;
>> int s;
>>
>> switch (cmd) {
>> case TUNGETVNETHDRSZ:
>> + if (!sz)
>> + return -EBADFD;
>> +
>> s = *sz;
>> if (put_user(s, sp))
>> return -EFAULT;
>> return 0;
>>
>> case TUNSETVNETHDRSZ:
>> + if (!sz)
>> + return -EBADFD;
>> +
>> if (get_user(s, sp))
>> return -EFAULT;
>> if (s < (int)sizeof(struct virtio_net_hdr))
>> @@ -80,12 +96,18 @@ static inline long tun_vnet_ioctl(int *sz, unsigned int *flags,
>> return 0;
>>
>> case TUNGETVNETLE:
>> + if (!flags)
>> + return -EBADFD;
>> +
>> s = !!(*flags & TUN_VNET_LE);
>> if (put_user(s, sp))
>> return -EFAULT;
>> return 0;
>>
>> case TUNSETVNETLE:
>> + if (!flags)
>> + return -EBADFD;
>> +
>> if (get_user(s, sp))
>> return -EFAULT;
>> if (s)
>> @@ -95,16 +117,56 @@ static inline long tun_vnet_ioctl(int *sz, unsigned int *flags,
>> return 0;
>>
>> case TUNGETVNETBE:
>> + if (!flags)
>> + return -EBADFD;
>> +
>> return tun_vnet_get_be(*flags, sp);
>>
>> case TUNSETVNETBE:
>> + if (!flags)
>> + return -EBADFD;
>> +
>> return tun_vnet_set_be(flags, sp);
>>
>> + case TUNGETVNETHASHCAP:
>> + return copy_to_user(argp, &cap, sizeof(cap)) ? -EFAULT : 0;
>> +
>> + case TUNSETVNETHASH:
>> + if (!hash)
>> + return -EBADFD;
>> +
>> + if (copy_from_user(&hash_buf, argp, sizeof(hash_buf)))
>> + return -EFAULT;
>> +
>> + *hash = hash_buf;
>> + return 0;
>> +
>> default:
>> - return -EINVAL;
>> + return fallback;
>> }
>> }
>>
>> +static inline void tun_vnet_hash_report(const struct tun_vnet_hash *hash,
>> + struct sk_buff *skb,
>> + const struct flow_keys_basic *keys,
>> + u32 value,
>> + tun_vnet_hash_add vnet_hash_add)
>> +{
>> + struct virtio_net_hash *report;
>> +
>> + if (!(hash->flags & TUN_VNET_HASH_REPORT))
>> + return;
>> +
>> + report = vnet_hash_add(skb);
>> + if (!report)
>> + return;
>> +
>> + *report = (struct virtio_net_hash) {
>> + .report = virtio_net_hash_report(hash->types, keys),
>> + .value = value
>> + };
>> +}
>> +
>> static inline int tun_vnet_hdr_get(int sz, unsigned int flags,
>> struct iov_iter *from,
>> struct virtio_net_hdr *hdr)
>> @@ -130,15 +192,15 @@ static inline int tun_vnet_hdr_get(int sz, unsigned int flags,
>> }
>>
>> static inline int tun_vnet_hdr_put(int sz, struct iov_iter *iter,
>> - const struct virtio_net_hdr *hdr)
>> + const void *hdr, int content_sz)
>> {
>> if (iov_iter_count(iter) < sz)
>> return -EINVAL;
>>
>> - if (copy_to_iter(hdr, sizeof(*hdr), iter) != sizeof(*hdr))
>> + if (copy_to_iter(hdr, content_sz, iter) != content_sz)
>> return -EFAULT;
>>
>> - if (iov_iter_zero(sz - sizeof(*hdr), iter) != sz - sizeof(*hdr))
>> + if (iov_iter_zero(sz - content_sz, iter) != sz - content_sz)
>> return -EFAULT;
>>
>> return 0;
>> @@ -151,32 +213,48 @@ static inline int tun_vnet_hdr_to_skb(unsigned int flags,
>> return virtio_net_hdr_to_skb(skb, hdr, tun_vnet_is_little_endian(flags));
>> }
>>
>> -static inline int tun_vnet_hdr_from_skb(unsigned int flags,
>> +static inline int tun_vnet_hdr_from_skb(int sz, unsigned int flags,
>> const struct net_device *dev,
>> const struct sk_buff *skb,
>> - struct virtio_net_hdr *hdr)
>> + tun_vnet_hash_find vnet_hash_find,
>> + struct virtio_net_hdr_v1_hash *hdr)
>> {
>> int vlan_hlen = skb_vlan_tag_present(skb) ? VLAN_HLEN : 0;
>> + const struct virtio_net_hash *report = sz < sizeof(struct virtio_net_hdr_v1_hash) ?
>> + NULL : vnet_hash_find(skb);
>> + int content_sz;
>> +
>> + if (report) {
>> + content_sz = sizeof(struct virtio_net_hdr_v1_hash);
>> +
>> + *hdr = (struct virtio_net_hdr_v1_hash) {
>> + .hdr = { .num_buffers = __cpu_to_virtio16(true, 1) },
>> + .hash_value = cpu_to_le32(report->value),
>> + .hash_report = cpu_to_le16(report->report)
>> + };
>> + } else {
>> + content_sz = sizeof(struct virtio_net_hdr);
>> + }
>>
>> - if (virtio_net_hdr_from_skb(skb, hdr,
>> + if (virtio_net_hdr_from_skb(skb, (struct virtio_net_hdr *)hdr,
>> tun_vnet_is_little_endian(flags), true,
>> vlan_hlen)) {
>> struct skb_shared_info *sinfo = skb_shinfo(skb);
>>
>> if (net_ratelimit()) {
>> netdev_err(dev, "unexpected GSO type: 0x%x, gso_size %d, hdr_len %d\n",
>> - sinfo->gso_type, tun_vnet16_to_cpu(flags, hdr->gso_size),
>> - tun_vnet16_to_cpu(flags, hdr->hdr_len));
>> + sinfo->gso_type, tun_vnet16_to_cpu(flags, hdr->hdr.gso_size),
>> + tun_vnet16_to_cpu(flags, hdr->hdr.hdr_len));
>> print_hex_dump(KERN_ERR, "tun: ",
>> DUMP_PREFIX_NONE,
>> 16, 1, skb->head,
>> - min(tun_vnet16_to_cpu(flags, hdr->hdr_len), 64), true);
>> + min(tun_vnet16_to_cpu(flags, hdr->hdr.hdr_len), 64), true);
>> }
>> WARN_ON_ONCE(1);
>> return -EINVAL;
>> }
>>
>> - return 0;
>> + return content_sz;
>> }
>>
>> #endif /* TUN_VNET_H */
>> diff --git a/include/linux/if_tap.h b/include/linux/if_tap.h
>> index 553552fa635c..5bbb343a6dba 100644
>> --- a/include/linux/if_tap.h
>> +++ b/include/linux/if_tap.h
>> @@ -4,6 +4,7 @@
>>
>> #include <net/sock.h>
>> #include <linux/skb_array.h>
>> +#include <uapi/linux/if_tun.h>
>>
>> struct file;
>> struct socket;
>> @@ -43,6 +44,7 @@ struct tap_dev {
>> int numqueues;
>> netdev_features_t tap_features;
>> int minor;
>> + struct tun_vnet_hash vnet_hash;
>>
>> void (*update_features)(struct tap_dev *tap, netdev_features_t features);
>> void (*count_tx_dropped)(struct tap_dev *tap);
>> diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h
>> index 287cdc81c939..d11e79b4e0dc 100644
>> --- a/include/uapi/linux/if_tun.h
>> +++ b/include/uapi/linux/if_tun.h
>> @@ -62,6 +62,34 @@
>> #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.
>> + *
>> + * The %TUN_VNET_HASH_REPORT flag set with this ioctl will be effective only
>> + * after calling the %TUNSETVNETHDRSZ ioctl with a number greater than or equal
>> + * to the size of &struct virtio_net_hdr_v1_hash.
>
> I think we don't need & here.
Documentation/doc-guide/kernel-doc.rst says &struct is a token for
struct cross-reference.
>
>> + *
>> + * The members added to the legacy header by %TUN_VNET_HASH_REPORT flag will
>> + * always be little-endian.
>> + *
>> + * This ioctl results in %EBADFD if the underlying device is deleted. It affects
>> + * all queues attached to the same device.
>> + *
>> + * This ioctl currently has no effect on XDP packets and packets with
>> + * queue_mapping set by TC.
>
> This needs to be fixed?
We don't use a hash value to select a queue in such a case so there is
no point to report one.
>
>> + */
>> +#define TUNSETVNETHASH _IOW('T', 229, struct tun_vnet_hash)
>> +
>> /* TUNSETIFF ifr flags */
>> #define IFF_TUN 0x0001
>> #define IFF_TAP 0x0002
>> @@ -115,4 +143,24 @@ 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
>
> Could we reuse TUNGETIFF by introduce new IFF_XXX stuffs?
That's certainly doable though I'm a bit worrying that exhausting all
bits of IFF_XXX.
>
>> + * @pad:
>> + * Should be filled with zero before passing to %TUNSETVNETHASH
>> + * @types:
>> + * Bitmask of allowed hash types
>
> What are they?
They are defined in the virtio spec and include/uapi/linux/virtio_net.h
contains them:
#define VIRTIO_NET_RSS_HASH_TYPE_IPv4 (1 << 0)
#define VIRTIO_NET_RSS_HASH_TYPE_TCPv4 (1 << 1)
#define VIRTIO_NET_RSS_HASH_TYPE_UDPv4 (1 << 2)
#define VIRTIO_NET_RSS_HASH_TYPE_IPv6 (1 << 3)
#define VIRTIO_NET_RSS_HASH_TYPE_TCPv6 (1 << 4)
#define VIRTIO_NET_RSS_HASH_TYPE_UDPv6 (1 << 5)
#define VIRTIO_NET_RSS_HASH_TYPE_IP_EX (1 << 6)
#define VIRTIO_NET_RSS_HASH_TYPE_TCP_EX (1 << 7)
#define VIRTIO_NET_RSS_HASH_TYPE_UDP_EX (1 << 8)
>
>> + */
>> +struct tun_vnet_hash {
>> + __u16 flags;
>> + __u8 pad[2];
>> + __u32 types;
>> +};
>> +
>> #endif /* _UAPI__IF_TUN_H */
>>
>> --
>> 2.46.2
>>
>
> Thanks
>
Powered by blists - more mailing lists