virtio-net have two usage of hashes: one is RSS and another is hash reporting. Conventionally the hash calculation was done by the VMM. However, computing the hash after the queue was chosen defeats the purpose of RSS.
Another approach is to use eBPF steering program. This approach has another downside: it cannot report the calculated hash due to the restrictive nature of eBPF.
Introduce the code to compute hashes to the kernel in order to overcome thse challenges.
An alternative solution is to extend the eBPF steering program so that it will be able to report to the userspace, but it is based on context rewrites, which is in feature freeze. We can adopt kfuncs, but they will not be UAPIs. We opt to ioctl to align with other relevant UAPIs (KVM and vhost_net).
The patches for QEMU to use this new feature was submitted as RFC and is available at: https://patchew.org/QEMU/20240915-hash-v3-0-79cb08d28647@daynix.com/
This work was presented at LPC 2024: https://lpc.events/event/18/contributions/1963/
V1 -> V2: Changed to introduce a new BPF program type.
Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com --- Changes in v8: - Disabled IPv6 to eliminate noises in tests. - Added a branch in tap to avoid unnecessary dissection when hash reporting is disabled. - Removed unnecessary rtnl_lock(). - Extracted code to handle new ioctls into separate functions to avoid adding extra NULL checks to the code handling other ioctls. - Introduced variable named "fd" to __tun_chr_ioctl(). - s/-/=/g in a patch message to avoid confusing Git. - Link to v7: https://lore.kernel.org/r/20250228-rss-v7-0-844205cbbdd6@daynix.com
Changes in v7: - Ensured to set hash_report to VIRTIO_NET_HASH_REPORT_NONE for VHOST_NET_F_VIRTIO_NET_HDR. - s/4/sizeof(u32)/ in patch "virtio_net: Add functions for hashing". - Added tap_skb_cb type. - Rebased. - Link to v6: https://lore.kernel.org/r/20250109-rss-v6-0-b1c90ad708f6@daynix.com
Changes in v6: - Extracted changes to fill vnet header holes into another series. - Squashed patches "skbuff: Introduce SKB_EXT_TUN_VNET_HASH", "tun: Introduce virtio-net hash reporting feature", and "tun: Introduce virtio-net RSS" into patch "tun: Introduce virtio-net hash feature". - Dropped the RFC tag. - Link to v5: https://lore.kernel.org/r/20241008-rss-v5-0-f3cf68df005d@daynix.com
Changes in v5: - Fixed a compilation error with CONFIG_TUN_VNET_CROSS_LE. - Optimized the calculation of the hash value according to: https://git.dpdk.org/dpdk/commit/?id=3fb1ea032bd6ff8317af5dac9af901f1f324cab... - Added patch "tun: Unify vnet implementation". - Dropped patch "tap: Pad virtio header with zero". - Added patch "selftest: tun: Test vnet ioctls without device". - Reworked selftests to skip for older kernels. - Documented the case when the underlying device is deleted and packets have queue_mapping set by TC. - Reordered test harness arguments. - Added code to handle fragmented packets. - Link to v4: https://lore.kernel.org/r/20240924-rss-v4-0-84e932ec0e6c@daynix.com
Changes in v4: - Moved tun_vnet_hash_ext to if_tun.h. - Renamed virtio_net_toeplitz() to virtio_net_toeplitz_calc(). - Replaced htons() with cpu_to_be16(). - Changed virtio_net_hash_rss() to return void. - Reordered variable declarations in virtio_net_hash_rss(). - Removed virtio_net_hdr_v1_hash_from_skb(). - Updated messages of "tap: Pad virtio header with zero" and "tun: Pad virtio header with zero". - Fixed vnet_hash allocation size. - Ensured to free vnet_hash when destructing tun_struct. - Link to v3: https://lore.kernel.org/r/20240915-rss-v3-0-c630015db082@daynix.com
Changes in v3: - Reverted back to add ioctl. - Split patch "tun: Introduce virtio-net hashing feature" into "tun: Introduce virtio-net hash reporting feature" and "tun: Introduce virtio-net RSS". - Changed to reuse hash values computed for automq instead of performing RSS hashing when hash reporting is requested but RSS is not. - Extracted relevant data from struct tun_struct to keep it minimal. - Added kernel-doc. - Changed to allow calling TUNGETVNETHASHCAP before TUNSETIFF. - Initialized num_buffers with 1. - Added a test case for unclassified packets. - Fixed error handling in tests. - Changed tests to verify that the queue index will not overflow. - Rebased. - Link to v2: https://lore.kernel.org/r/20231015141644.260646-1-akihiko.odaki@daynix.com
--- Akihiko Odaki (6): virtio_net: Add functions for hashing net: flow_dissector: Export flow_keys_dissector_symmetric tun: Introduce virtio-net hash feature selftest: tun: Test vnet ioctls without device selftest: tun: Add tests for virtio-net hashing vhost/net: Support VIRTIO_NET_F_HASH_REPORT
Documentation/networking/tuntap.rst | 7 + drivers/net/Kconfig | 1 + drivers/net/tap.c | 67 +++- drivers/net/tun.c | 98 +++++- drivers/net/tun_vnet.h | 159 ++++++++- drivers/vhost/net.c | 49 +-- include/linux/if_tap.h | 2 + include/linux/skbuff.h | 3 + include/linux/virtio_net.h | 188 ++++++++++ include/net/flow_dissector.h | 1 + include/uapi/linux/if_tun.h | 75 ++++ net/core/flow_dissector.c | 3 +- net/core/skbuff.c | 4 + tools/testing/selftests/net/Makefile | 2 +- tools/testing/selftests/net/tun.c | 656 ++++++++++++++++++++++++++++++++++- 15 files changed, 1254 insertions(+), 61 deletions(-) --- base-commit: dd83757f6e686a2188997cb58b5975f744bb7786 change-id: 20240403-rss-e737d89efa77 prerequisite-change-id: 20241230-tun-66e10a49b0c7:v6 prerequisite-patch-id: 871dc5f146fb6b0e3ec8612971a8e8190472c0fb prerequisite-patch-id: 2797ed249d32590321f088373d4055ff3f430a0e prerequisite-patch-id: ea3370c72d4904e2f0536ec76ba5d26784c0cede prerequisite-patch-id: 837e4cf5d6b451424f9b1639455e83a260c4440d prerequisite-patch-id: ea701076f57819e844f5a35efe5cbc5712d3080d prerequisite-patch-id: 701646fb43ad04cc64dd2bf13c150ccbe6f828ce prerequisite-patch-id: 53176dae0c003f5b6c114d43f936cf7140d31bb5 prerequisite-change-id: 20250116-buffers-96e14bf023fc:v2 prerequisite-patch-id: 25fd4f99d4236a05a5ef16ab79f3e85ee57e21cc
Best regards,
They are useful to implement VIRTIO_NET_F_RSS and VIRTIO_NET_F_HASH_REPORT.
Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com --- include/linux/virtio_net.h | 188 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 188 insertions(+)
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 02a9f4dc594d02372a6c1850cd600eff9d000d8d..426f33b4b82440d61b2af9fdc4c0b0d4c571b2c5 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -9,6 +9,194 @@ #include <uapi/linux/tcp.h> #include <uapi/linux/virtio_net.h>
+struct virtio_net_hash { + u32 value; + u16 report; +}; + +struct virtio_net_toeplitz_state { + u32 hash; + const u32 *key; +}; + +#define VIRTIO_NET_SUPPORTED_HASH_TYPES (VIRTIO_NET_RSS_HASH_TYPE_IPv4 | \ + VIRTIO_NET_RSS_HASH_TYPE_TCPv4 | \ + VIRTIO_NET_RSS_HASH_TYPE_UDPv4 | \ + VIRTIO_NET_RSS_HASH_TYPE_IPv6 | \ + VIRTIO_NET_RSS_HASH_TYPE_TCPv6 | \ + VIRTIO_NET_RSS_HASH_TYPE_UDPv6) + +#define VIRTIO_NET_RSS_MAX_KEY_SIZE 40 + +static inline void virtio_net_toeplitz_convert_key(u32 *input, size_t len) +{ + while (len >= sizeof(*input)) { + *input = be32_to_cpu((__force __be32)*input); + input++; + len -= sizeof(*input); + } +} + +static inline void virtio_net_toeplitz_calc(struct virtio_net_toeplitz_state *state, + const __be32 *input, size_t len) +{ + while (len >= sizeof(*input)) { + for (u32 map = be32_to_cpu(*input); map; map &= (map - 1)) { + u32 i = ffs(map); + + state->hash ^= state->key[0] << (32 - i) | + (u32)((u64)state->key[1] >> i); + } + + state->key++; + input++; + len -= sizeof(*input); + } +} + +static inline u8 virtio_net_hash_key_length(u32 types) +{ + size_t len = 0; + + if (types & VIRTIO_NET_HASH_REPORT_IPv4) + len = max(len, + sizeof(struct flow_dissector_key_ipv4_addrs)); + + if (types & + (VIRTIO_NET_HASH_REPORT_TCPv4 | VIRTIO_NET_HASH_REPORT_UDPv4)) + len = max(len, + sizeof(struct flow_dissector_key_ipv4_addrs) + + sizeof(struct flow_dissector_key_ports)); + + if (types & VIRTIO_NET_HASH_REPORT_IPv6) + len = max(len, + sizeof(struct flow_dissector_key_ipv6_addrs)); + + if (types & + (VIRTIO_NET_HASH_REPORT_TCPv6 | VIRTIO_NET_HASH_REPORT_UDPv6)) + len = max(len, + sizeof(struct flow_dissector_key_ipv6_addrs) + + sizeof(struct flow_dissector_key_ports)); + + return len + sizeof(u32); +} + +static inline u32 virtio_net_hash_report(u32 types, + const struct flow_keys_basic *keys) +{ + switch (keys->basic.n_proto) { + case cpu_to_be16(ETH_P_IP): + if (!(keys->control.flags & FLOW_DIS_IS_FRAGMENT)) { + if (keys->basic.ip_proto == IPPROTO_TCP && + (types & VIRTIO_NET_RSS_HASH_TYPE_TCPv4)) + return VIRTIO_NET_HASH_REPORT_TCPv4; + + if (keys->basic.ip_proto == IPPROTO_UDP && + (types & VIRTIO_NET_RSS_HASH_TYPE_UDPv4)) + return VIRTIO_NET_HASH_REPORT_UDPv4; + } + + if (types & VIRTIO_NET_RSS_HASH_TYPE_IPv4) + return VIRTIO_NET_HASH_REPORT_IPv4; + + return VIRTIO_NET_HASH_REPORT_NONE; + + case cpu_to_be16(ETH_P_IPV6): + if (!(keys->control.flags & FLOW_DIS_IS_FRAGMENT)) { + if (keys->basic.ip_proto == IPPROTO_TCP && + (types & VIRTIO_NET_RSS_HASH_TYPE_TCPv6)) + return VIRTIO_NET_HASH_REPORT_TCPv6; + + if (keys->basic.ip_proto == IPPROTO_UDP && + (types & VIRTIO_NET_RSS_HASH_TYPE_UDPv6)) + return VIRTIO_NET_HASH_REPORT_UDPv6; + } + + if (types & VIRTIO_NET_RSS_HASH_TYPE_IPv6) + return VIRTIO_NET_HASH_REPORT_IPv6; + + return VIRTIO_NET_HASH_REPORT_NONE; + + default: + return VIRTIO_NET_HASH_REPORT_NONE; + } +} + +static inline void virtio_net_hash_rss(const struct sk_buff *skb, + u32 types, const u32 *key, + struct virtio_net_hash *hash) +{ + struct virtio_net_toeplitz_state toeplitz_state = { .key = key }; + struct flow_keys flow; + struct flow_keys_basic flow_basic; + u16 report; + + if (!skb_flow_dissect_flow_keys(skb, &flow, 0)) { + hash->report = VIRTIO_NET_HASH_REPORT_NONE; + return; + } + + flow_basic = (struct flow_keys_basic) { + .control = flow.control, + .basic = flow.basic + }; + + report = virtio_net_hash_report(types, &flow_basic); + + switch (report) { + case VIRTIO_NET_HASH_REPORT_IPv4: + virtio_net_toeplitz_calc(&toeplitz_state, + (__be32 *)&flow.addrs.v4addrs, + sizeof(flow.addrs.v4addrs)); + break; + + case VIRTIO_NET_HASH_REPORT_TCPv4: + virtio_net_toeplitz_calc(&toeplitz_state, + (__be32 *)&flow.addrs.v4addrs, + sizeof(flow.addrs.v4addrs)); + virtio_net_toeplitz_calc(&toeplitz_state, &flow.ports.ports, + sizeof(flow.ports.ports)); + break; + + case VIRTIO_NET_HASH_REPORT_UDPv4: + virtio_net_toeplitz_calc(&toeplitz_state, + (__be32 *)&flow.addrs.v4addrs, + sizeof(flow.addrs.v4addrs)); + virtio_net_toeplitz_calc(&toeplitz_state, &flow.ports.ports, + sizeof(flow.ports.ports)); + break; + + case VIRTIO_NET_HASH_REPORT_IPv6: + virtio_net_toeplitz_calc(&toeplitz_state, + (__be32 *)&flow.addrs.v6addrs, + sizeof(flow.addrs.v6addrs)); + break; + + case VIRTIO_NET_HASH_REPORT_TCPv6: + virtio_net_toeplitz_calc(&toeplitz_state, + (__be32 *)&flow.addrs.v6addrs, + sizeof(flow.addrs.v6addrs)); + virtio_net_toeplitz_calc(&toeplitz_state, &flow.ports.ports, + sizeof(flow.ports.ports)); + break; + + case VIRTIO_NET_HASH_REPORT_UDPv6: + virtio_net_toeplitz_calc(&toeplitz_state, + (__be32 *)&flow.addrs.v6addrs, + sizeof(flow.addrs.v6addrs)); + virtio_net_toeplitz_calc(&toeplitz_state, &flow.ports.ports, + sizeof(flow.ports.ports)); + break; + + default: + hash->report = VIRTIO_NET_HASH_REPORT_NONE; + return; + } + + hash->value = toeplitz_state.hash; + hash->report = report; +} + static inline bool virtio_net_hdr_match_proto(__be16 protocol, __u8 gso_type) { switch (gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
flow_keys_dissector_symmetric is useful to derive a symmetric hash and to know its source such as IPv4, IPv6, TCP, and UDP.
Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com --- include/net/flow_dissector.h | 1 + net/core/flow_dissector.c | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h index ced79dc8e8560e25a4dd567a04f5710b53452b45..d01c1ec77b7d21b17c14b05c47e3cdda39651bec 100644 --- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -423,6 +423,7 @@ __be32 flow_get_u32_src(const struct flow_keys *flow); __be32 flow_get_u32_dst(const struct flow_keys *flow);
extern struct flow_dissector flow_keys_dissector; +extern struct flow_dissector flow_keys_dissector_symmetric; extern struct flow_dissector flow_keys_basic_dissector;
/* struct flow_keys_digest: diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 9cd8de6bebb543c3d672f576e03b29aa86b9d34a..32c7ee31330cf52df05d7a23b3e50d1a1bed9908 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -1862,7 +1862,8 @@ void make_flow_keys_digest(struct flow_keys_digest *digest, } EXPORT_SYMBOL(make_flow_keys_digest);
-static struct flow_dissector flow_keys_dissector_symmetric __read_mostly; +struct flow_dissector flow_keys_dissector_symmetric __read_mostly; +EXPORT_SYMBOL(flow_keys_dissector_symmetric);
u32 __skb_get_hash_symmetric_net(const struct net *net, const struct sk_buff *skb) {
Hash reporting ==============
Allow the guest to reuse the hash value to make receive steering consistent between the host and guest, and to save hash computation.
RSS ===
RSS is a receive steering algorithm that can be negotiated to use with virtio_net. Conventionally the hash calculation was done by the VMM. However, computing the hash after the queue was chosen defeats the purpose of RSS.
Another approach is to use eBPF steering program. This approach has another downside: it cannot report the calculated hash due to the restrictive nature of eBPF steering program.
Introduce the code to perform RSS to the kernel in order to overcome thse challenges. An alternative solution is to extend the eBPF steering program so that it will be able to report to the userspace, but I didn't opt for it because extending the current mechanism of eBPF steering program as is because it relies on legacy context rewriting, and introducing kfunc-based eBPF will result in non-UAPI dependency while the other relevant virtualization APIs such as KVM and vhost_net are UAPIs.
Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com --- Documentation/networking/tuntap.rst | 7 ++ drivers/net/Kconfig | 1 + drivers/net/tap.c | 67 ++++++++++++++- drivers/net/tun.c | 98 +++++++++++++++++----- drivers/net/tun_vnet.h | 159 ++++++++++++++++++++++++++++++++++-- include/linux/if_tap.h | 2 + include/linux/skbuff.h | 3 + include/uapi/linux/if_tun.h | 75 +++++++++++++++++ net/core/skbuff.c | 4 + 9 files changed, 385 insertions(+), 31 deletions(-)
diff --git a/Documentation/networking/tuntap.rst b/Documentation/networking/tuntap.rst index 4d7087f727be5e37dfbf5066a9e9c872cc98898d..86b4ae8caa8ad062c1e558920be42ce0d4217465 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 1fd5acdc73c6af0e1a861867039c3624fc618e25..aecfd244dd83585fea2c5b815dcd787c58166c28 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/tap.c b/drivers/net/tap.c index d4ece538f1b23789ca60caa6232690e4d0a4d14a..e5c92259396b379f2532025a0fdf1db36156a681 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -49,6 +49,10 @@ struct major_info { struct list_head next; };
+struct tap_skb_cb { + struct virtio_net_hash hash; +}; + #define GOODCOPY_LEN 128
static const struct proto_ops tap_socket_ops; @@ -179,6 +183,22 @@ static void tap_put_queue(struct tap_queue *q) sock_put(&q->sk); }
+static struct tap_skb_cb *tap_skb_cb(const struct sk_buff *skb) +{ + BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct tap_skb_cb)); + return (struct tap_skb_cb *)skb->cb; +} + +static struct virtio_net_hash *tap_add_hash(struct sk_buff *skb) +{ + return &tap_skb_cb(skb)->hash; +} + +static const struct virtio_net_hash *tap_find_hash(const struct sk_buff *skb) +{ + return &tap_skb_cb(skb)->hash; +} + /* * 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 +209,7 @@ 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 @@ -196,17 +217,47 @@ static struct tap_queue *tap_get_queue(struct tap_dev *tap, * racing against queue removal. */ int numvtaps = READ_ONCE(tap->numvtaps); + struct tun_vnet_hash_container *vnet_hash = rcu_dereference(tap->vnet_hash); __u32 rxq;
+ *tap_skb_cb(skb) = (struct tap_skb_cb) { + .hash = { .report = VIRTIO_NET_HASH_REPORT_NONE } + }; + if (!numvtaps) goto out;
if (numvtaps == 1) goto single;
+ if (vnet_hash) { + if ((vnet_hash->common.flags & TUN_VNET_HASH_RSS)) { + rxq = tun_vnet_rss_select_queue(numvtaps, vnet_hash, skb, tap_add_hash); + queue = rcu_dereference(tap->taps[rxq]); + goto out; + } + + 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; + } + } else { + rxq = skb_get_hash(skb); + } + /* Check if we can use flow to select a queue */ - rxq = skb_get_hash(skb); if (rxq) { + tun_vnet_hash_report(vnet_hash, skb, &keys_basic, rxq, tap_add_hash); queue = rcu_dereference(tap->taps[rxq % numvtaps]); goto out; } @@ -711,11 +762,12 @@ 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) return ret;
@@ -992,6 +1044,15 @@ static long tap_ioctl(struct file *file, unsigned int cmd, rtnl_unlock(); return ret;
+ case TUNGETVNETHASHCAP: + return tun_vnet_ioctl_gethashcap(argp); + + case TUNSETVNETHASH: + rtnl_lock(); + tap = rtnl_dereference(q->tap); + ret = tap ? tun_vnet_ioctl_sethash(&tap->vnet_hash, true, argp) : -EBADFD; + rtnl_unlock(); + case SIOCGIFHWADDR: rtnl_lock(); tap = tap_get_tap_dev(q); diff --git a/drivers/net/tun.c b/drivers/net/tun.c index d8f4d3e996a7a81d1f8b04635054081671a14f07..520013df416e93d3a50b46be9b53ae9ab410eab4 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_container __rcu *vnet_hash; struct ethtool_link_ksettings link_ksettings; /* init args */ struct file *file; @@ -451,20 +452,37 @@ 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 * the userspace application move between processors, we may get a * different rxq no. here. */ -static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb) +static u16 tun_automq_select_queue(struct tun_struct *tun, + const struct tun_vnet_hash_container *vnet_hash, + 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 +491,13 @@ 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(vnet_hash, skb, &keys_basic, skb->l4_hash ? skb->hash : txq, + tun_add_hash); + return txq; }
@@ -500,10 +525,17 @@ static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, u16 ret;
rcu_read_lock(); - if (rcu_dereference(tun->steering_prog)) + if (rcu_dereference(tun->steering_prog)) { ret = tun_ebpf_select_queue(tun, skb); - else - ret = tun_automq_select_queue(tun, skb); + } else { + struct tun_vnet_hash_container *vnet_hash = rcu_dereference(tun->vnet_hash); + + if (vnet_hash && (vnet_hash->common.flags & TUN_VNET_HASH_RSS)) + ret = tun_vnet_rss_select_queue(READ_ONCE(tun->numqueues), vnet_hash, + skb, tun_add_hash); + else + ret = tun_automq_select_queue(tun, vnet_hash, skb); + } rcu_read_unlock();
return ret; @@ -1987,7 +2019,7 @@ static ssize_t tun_put_user_xdp(struct tun_struct *tun, ssize_t ret;
if (tun->flags & IFF_VNET_HDR) { - struct virtio_net_hdr gso = { 0 }; + struct virtio_net_hdr_v1_hash gso = { 0 };
vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz); ret = tun_vnet_hdr_put(vnet_hdr_sz, iter, &gso); @@ -2040,9 +2072,10 @@ 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;
- 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) return ret;
@@ -2223,6 +2256,7 @@ static void tun_free_netdev(struct net_device *dev) security_tun_dev_free_security(tun->security); __tun_set_ebpf(tun, &tun->steering_prog, NULL); __tun_set_ebpf(tun, &tun->filter_prog, NULL); + kfree_rcu_mightsleep(rcu_access_pointer(tun->vnet_hash)); }
static void tun_setup(struct net_device *dev) @@ -2921,13 +2955,9 @@ static int tun_set_queue(struct file *file, struct ifreq *ifr) }
static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **prog_p, - void __user *data) + int fd) { struct bpf_prog *prog; - int fd; - - if (copy_from_user(&fd, data, sizeof(fd))) - return -EFAULT;
if (fd == -1) { prog = NULL; @@ -2993,7 +3023,9 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, int ifindex; int sndbuf; int ret; + int fd; bool do_notify = false; + struct tun_vnet_hash_container *vnet_hash;
if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) { @@ -3020,7 +3052,8 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, rtnl_lock();
tun = tun_get(tfile); - if (cmd == TUNSETIFF) { + switch (cmd) { + case TUNSETIFF: ret = -EEXIST; if (tun) goto unlock; @@ -3035,8 +3068,8 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, if (copy_to_user(argp, &ifr, ifreq_len)) ret = -EFAULT; goto unlock; - } - if (cmd == TUNSETIFINDEX) { + + case TUNSETIFINDEX: ret = -EPERM; if (tun) goto unlock; @@ -3050,6 +3083,10 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, ret = 0; tfile->ifindex = ifindex; goto unlock; + + case TUNGETVNETHASHCAP: + ret = tun_vnet_ioctl_gethashcap(argp); + goto unlock; }
ret = -EBADFD; @@ -3230,11 +3267,27 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, break;
case TUNSETSTEERINGEBPF: - ret = tun_set_ebpf(tun, &tun->steering_prog, argp); + if (get_user(fd, (int __user *)argp)) { + ret = -EFAULT; + break; + } + + vnet_hash = rtnl_dereference(tun->vnet_hash); + if (fd != -1 && vnet_hash && (vnet_hash->common.flags & TUN_VNET_HASH_RSS)) { + ret = -EBUSY; + break; + } + + ret = tun_set_ebpf(tun, &tun->steering_prog, fd); break;
case TUNSETFILTEREBPF: - ret = tun_set_ebpf(tun, &tun->filter_prog, argp); + if (get_user(fd, (int __user *)argp)) { + ret = -EFAULT; + break; + } + + ret = tun_set_ebpf(tun, &tun->filter_prog, fd); break;
case TUNSETCARRIER: @@ -3252,8 +3305,15 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, ret = open_related_ns(&net->ns, get_net_ns); break;
+ case TUNSETVNETHASH: + ret = tun_vnet_ioctl_sethash(&tun->vnet_hash, + !rtnl_dereference(tun->steering_prog), + argp); + break; + default: - ret = tun_vnet_ioctl(&tun->vnet_hdr_sz, &tun->flags, cmd, argp); + ret = tun_vnet_ioctl(&tun->vnet_hdr_sz, &tun->flags, + cmd, argp); break; }
diff --git a/drivers/net/tun_vnet.h b/drivers/net/tun_vnet.h index 58b9ac7a5fc4084c789fe94fe36b5f8631bf1fa4..8e7d51fb0b4742cef56e7c5ad778b156cc654bed 100644 --- a/drivers/net/tun_vnet.h +++ b/drivers/net/tun_vnet.h @@ -6,6 +6,16 @@ #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 *); + +struct tun_vnet_hash_container { + struct tun_vnet_hash common; + struct tun_vnet_hash_rss rss; + u32 rss_key[VIRTIO_NET_RSS_MAX_KEY_SIZE]; + u16 rss_indirection_table[]; +}; + static inline bool tun_vnet_legacy_is_little_endian(unsigned int flags) { bool be = IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) && @@ -107,6 +117,123 @@ static inline long tun_vnet_ioctl(int *vnet_hdr_sz, unsigned int *flags, } }
+static inline long tun_vnet_ioctl_gethashcap(void __user *argp) +{ + static const struct tun_vnet_hash cap = { + .flags = TUN_VNET_HASH_REPORT | TUN_VNET_HASH_RSS, + .types = VIRTIO_NET_SUPPORTED_HASH_TYPES + }; + + return copy_to_user(argp, &cap, sizeof(cap)) ? -EFAULT : 0; +} + +static inline long tun_vnet_ioctl_sethash(struct tun_vnet_hash_container __rcu **hashp, + bool can_rss, void __user *argp) +{ + struct tun_vnet_hash hash_buf; + struct tun_vnet_hash_container *hash; + + if (copy_from_user(&hash_buf, argp, sizeof(hash_buf))) + return -EFAULT; + argp = (struct tun_vnet_hash __user *)argp + 1; + + if (hash_buf.flags & TUN_VNET_HASH_RSS) { + struct tun_vnet_hash_rss rss; + size_t indirection_table_size; + size_t key_size; + size_t size; + + if (!can_rss) + return -EBUSY; + + if (copy_from_user(&rss, argp, sizeof(rss))) + return -EFAULT; + argp = (struct tun_vnet_hash_rss __user *)argp + 1; + + indirection_table_size = ((size_t)rss.indirection_table_mask + 1) * 2; + key_size = virtio_net_hash_key_length(hash_buf.types); + size = struct_size(hash, rss_indirection_table, + (size_t)rss.indirection_table_mask + 1); + + hash = kmalloc(size, GFP_KERNEL); + if (!hash) + return -ENOMEM; + + if (copy_from_user(hash->rss_indirection_table, + argp, indirection_table_size)) { + kfree(hash); + return -EFAULT; + } + argp = (u16 __user *)argp + rss.indirection_table_mask + 1; + + if (copy_from_user(hash->rss_key, argp, key_size)) { + kfree(hash); + return -EFAULT; + } + + virtio_net_toeplitz_convert_key(hash->rss_key, key_size); + hash->rss = rss; + } else { + hash = kmalloc(sizeof(hash->common), GFP_KERNEL); + if (!hash) + return -ENOMEM; + } + + hash->common = hash_buf; + kfree_rcu_mightsleep(rcu_replace_pointer_rtnl(*hashp, hash)); + return 0; +} + +static void tun_vnet_hash_report(const struct tun_vnet_hash_container *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 || !(hash->common.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->common.types, keys), + .value = value + }; +} + +static u16 tun_vnet_rss_select_queue(u32 numqueues, + const struct tun_vnet_hash_container *hash, + struct sk_buff *skb, + tun_vnet_hash_add vnet_hash_add) +{ + struct virtio_net_hash *report; + struct virtio_net_hash ret; + u16 txq, index; + + if (!numqueues) + return 0; + + virtio_net_hash_rss(skb, hash->common.types, hash->rss_key, &ret); + + if (!ret.report) + return hash->rss.unclassified_queue % numqueues; + + if (hash->common.flags & TUN_VNET_HASH_REPORT) { + report = vnet_hash_add(skb); + if (report) + *report = ret; + } + + index = ret.value & hash->rss.indirection_table_mask; + txq = READ_ONCE(hash->rss_indirection_table[index]); + + return txq % numqueues; +} + static inline int tun_vnet_hdr_get(int sz, unsigned int flags, struct iov_iter *from, struct virtio_net_hdr *hdr) @@ -135,15 +262,17 @@ 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 struct virtio_net_hdr_v1_hash *hdr) { + int content_sz = MIN(sizeof(*hdr), sz); + if (unlikely(iov_iter_count(iter) < sz)) return -EINVAL;
- if (unlikely(copy_to_iter(hdr, sizeof(*hdr), iter) != sizeof(*hdr))) + if (unlikely(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; @@ -155,26 +284,38 @@ static inline int tun_vnet_hdr_to_skb(unsigned int flags, struct sk_buff *skb, 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); + + *hdr = (struct virtio_net_hdr_v1_hash) { + .hash_report = VIRTIO_NET_HASH_REPORT_NONE + }; + + if (report) { + hdr->hash_value = cpu_to_le32(report->value); + hdr->hash_report = cpu_to_le16(report->report); + }
- 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; diff --git a/include/linux/if_tap.h b/include/linux/if_tap.h index 553552fa635c3e1e53d1a63c203d32e4c4fd5a4f..7334c46a3f101675a0d4e5a036987cfe18842f9f 100644 --- a/include/linux/if_tap.h +++ b/include/linux/if_tap.h @@ -31,6 +31,7 @@ static inline struct ptr_ring *tap_get_ptr_ring(struct file *f) #define MAX_TAP_QUEUES 256
struct tap_queue; +struct tun_vnet_hash_container;
struct tap_dev { struct net_device *dev; @@ -43,6 +44,7 @@ struct tap_dev { int numqueues; netdev_features_t tap_features; int minor; + struct tun_vnet_hash_container __rcu *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/linux/skbuff.h b/include/linux/skbuff.h index bb2b751d274acff931281a72e8b4b0c699b4e8af..cdd793f1c360ad5f63fcc4cbf67d845f5e2ccf6f 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -4842,6 +4842,9 @@ enum skb_ext_id { #endif #if IS_ENABLED(CONFIG_MCTP_FLOWS) SKB_EXT_MCTP, +#endif +#if IS_ENABLED(CONFIG_TUN) + SKB_EXT_TUN_VNET_HASH, #endif SKB_EXT_NUM, /* must be last */ }; diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h index 287cdc81c9390c289a30545aa7ed23d81c3329d3..4887f97500a870c7ef3c96a5837b2d0a5a225040 100644 --- a/include/uapi/linux/if_tun.h +++ b/include/uapi/linux/if_tun.h @@ -62,6 +62,42 @@ #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 argument is a pointer to the compound of the following in order if + * %TUN_VNET_HASH_RSS is set: + * + * 1. &struct tun_vnet_hash + * 2. &struct tun_vnet_hash_rss + * 3. Indirection table + * 4. Key + * + * 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. + * + * 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. + */ +#define TUNSETVNETHASH _IOW('T', 229, struct tun_vnet_hash) + /* TUNSETIFF ifr flags */ #define IFF_TUN 0x0001 #define IFF_TAP 0x0002 @@ -115,4 +151,43 @@ 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 + +/** + * define TUN_VNET_HASH_RSS - Request virtio_net RSS + * + * This is mutually exclusive with eBPF steering program. + */ +#define TUN_VNET_HASH_RSS 0x0002 + +/** + * 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; +}; + +/** + * struct tun_vnet_hash_rss - virtio_net RSS configuration + * @indirection_table_mask: + * Bitmask to be applied to the indirection table index + * @unclassified_queue: + * The index of the queue to place unclassified packets in + */ +struct tun_vnet_hash_rss { + __u16 indirection_table_mask; + __u16 unclassified_queue; +}; + #endif /* _UAPI__IF_TUN_H */ diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 7b03b64fdcb276f68ce881d1d8da8e4c6b897efc..aa2a091b649f0c9d6e0196f34f345ba78b5498fb 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -64,6 +64,7 @@ #include <linux/mpls.h> #include <linux/kcov.h> #include <linux/iov_iter.h> +#include <linux/virtio_net.h>
#include <net/protocol.h> #include <net/dst.h> @@ -4969,6 +4970,9 @@ static const u8 skb_ext_type_len[] = { #if IS_ENABLED(CONFIG_MCTP_FLOWS) [SKB_EXT_MCTP] = SKB_EXT_CHUNKSIZEOF(struct mctp_flow), #endif +#if IS_ENABLED(CONFIG_TUN) + [SKB_EXT_TUN_VNET_HASH] = SKB_EXT_CHUNKSIZEOF(struct virtio_net_hash), +#endif };
static __always_inline unsigned int skb_ext_total_length(void)
On Thu, 06 Mar 2025 18:56:33 +0900 Akihiko Odaki wrote:
Hash reporting
Allow the guest to reuse the hash value to make receive steering consistent between the host and guest, and to save hash computation.
RSS
RSS is a receive steering algorithm that can be negotiated to use with virtio_net. Conventionally the hash calculation was done by the VMM. However, computing the hash after the queue was chosen defeats the purpose of RSS.
Another approach is to use eBPF steering program. This approach has another downside: it cannot report the calculated hash due to the restrictive nature of eBPF steering program.
Introduce the code to perform RSS to the kernel in order to overcome thse challenges. An alternative solution is to extend the eBPF steering program so that it will be able to report to the userspace, but I didn't opt for it because extending the current mechanism of eBPF steering program as is because it relies on legacy context rewriting, and introducing kfunc-based eBPF will result in non-UAPI dependency while the other relevant virtualization APIs such as KVM and vhost_net are UAPIs.
drivers/net/tap.c:1056:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] 1056 | case SIOCGIFHWADDR: | ^ drivers/net/tap.c:1056:2: note: insert '__attribute__((fallthrough));' to silence this warning 1056 | case SIOCGIFHWADDR: | ^ | __attribute__((fallthrough)); drivers/net/tap.c:1056:2: note: insert 'break;' to avoid fall-through 1056 | case SIOCGIFHWADDR: | ^ | break;
Hi Akihiko,
kernel test robot noticed the following build warnings:
[auto build test WARNING on dd83757f6e686a2188997cb58b5975f744bb7786]
url: https://github.com/intel-lab-lkp/linux/commits/Akihiko-Odaki/virtio_net-Add-... base: dd83757f6e686a2188997cb58b5975f744bb7786 patch link: https://lore.kernel.org/r/20250306-rss-v8-3-7ab4f56ff423%40daynix.com patch subject: [PATCH net-next v8 3/6] tun: Introduce virtio-net hash feature config: x86_64-buildonly-randconfig-001-20250307 (https://download.01.org/0day-ci/archive/20250307/202503071936.EzoojQZO-lkp@i...) compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250307/202503071936.EzoojQZO-lkp@i...)
If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot lkp@intel.com | Closes: https://lore.kernel.org/oe-kbuild-all/202503071936.EzoojQZO-lkp@intel.com/
All warnings (new ones prefixed by >>):
drivers/net/tap.c:1056:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
1056 | case SIOCGIFHWADDR: | ^ drivers/net/tap.c:1056:2: note: insert '__attribute__((fallthrough));' to silence this warning 1056 | case SIOCGIFHWADDR: | ^ | __attribute__((fallthrough)); drivers/net/tap.c:1056:2: note: insert 'break;' to avoid fall-through 1056 | case SIOCGIFHWADDR: | ^ | break; 1 warning generated.
vim +1056 drivers/net/tap.c
2be5c76794b0e5 drivers/net/macvtap.c Vlad Yasevich 2013-06-25 964 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 965 /* 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 966 * provide compatibility with generic tun/tap interface 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 967 */ 635b8c8ecdd271 drivers/net/tap.c Sainath Grandhi 2017-02-10 968 static long tap_ioctl(struct file *file, unsigned int cmd, 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 969 unsigned long arg) 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 970 { 635b8c8ecdd271 drivers/net/tap.c Sainath Grandhi 2017-02-10 971 struct tap_queue *q = file->private_data; 6fe3faf86757eb drivers/net/tap.c Sainath Grandhi 2017-02-10 972 struct tap_dev *tap; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 973 void __user *argp = (void __user *)arg; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 974 struct ifreq __user *ifr = argp; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 975 unsigned int __user *up = argp; 39ec7de7092ba9 drivers/net/macvtap.c Michael S. Tsirkin 2014-12-16 976 unsigned short u; 55afbd0810922a drivers/net/macvtap.c Michael S. Tsirkin 2010-04-29 977 int __user *sp = argp; 7f460d30c8e130 drivers/net/macvtap.c Justin Cormack 2015-05-13 978 struct sockaddr sa; 55afbd0810922a drivers/net/macvtap.c Michael S. Tsirkin 2010-04-29 979 int s; 02df55d28c6001 drivers/net/macvtap.c Arnd Bergmann 2010-02-18 980 int ret; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 981 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 982 switch (cmd) { 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 983 case TUNSETIFF: 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 984 /* ignore the name, just look at flags */ 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 985 if (get_user(u, &ifr->ifr_flags)) 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 986 return -EFAULT; b9fb9ee07e67fc drivers/net/macvtap.c Arnd Bergmann 2010-02-18 987 b9fb9ee07e67fc drivers/net/macvtap.c Arnd Bergmann 2010-02-18 988 ret = 0; 635b8c8ecdd271 drivers/net/tap.c Sainath Grandhi 2017-02-10 989 if ((u & ~TAP_IFFEATURES) != (IFF_NO_PI | IFF_TAP)) b9fb9ee07e67fc drivers/net/macvtap.c Arnd Bergmann 2010-02-18 990 ret = -EINVAL; b9fb9ee07e67fc drivers/net/macvtap.c Arnd Bergmann 2010-02-18 991 else 635b8c8ecdd271 drivers/net/tap.c Sainath Grandhi 2017-02-10 992 q->flags = (q->flags & ~TAP_IFFEATURES) | u; b9fb9ee07e67fc drivers/net/macvtap.c Arnd Bergmann 2010-02-18 993 b9fb9ee07e67fc drivers/net/macvtap.c Arnd Bergmann 2010-02-18 994 return ret; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 995 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 996 case TUNGETIFF: 441ac0fcaadc76 drivers/net/macvtap.c Vlad Yasevich 2013-06-25 997 rtnl_lock(); 6fe3faf86757eb drivers/net/tap.c Sainath Grandhi 2017-02-10 998 tap = tap_get_tap_dev(q); 6fe3faf86757eb drivers/net/tap.c Sainath Grandhi 2017-02-10 999 if (!tap) { 441ac0fcaadc76 drivers/net/macvtap.c Vlad Yasevich 2013-06-25 1000 rtnl_unlock(); 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1001 return -ENOLINK; 441ac0fcaadc76 drivers/net/macvtap.c Vlad Yasevich 2013-06-25 1002 } 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1003 02df55d28c6001 drivers/net/macvtap.c Arnd Bergmann 2010-02-18 1004 ret = 0; 39ec7de7092ba9 drivers/net/macvtap.c Michael S. Tsirkin 2014-12-16 1005 u = q->flags; 6fe3faf86757eb drivers/net/tap.c Sainath Grandhi 2017-02-10 1006 if (copy_to_user(&ifr->ifr_name, tap->dev->name, IFNAMSIZ) || 39ec7de7092ba9 drivers/net/macvtap.c Michael S. Tsirkin 2014-12-16 1007 put_user(u, &ifr->ifr_flags)) 02df55d28c6001 drivers/net/macvtap.c Arnd Bergmann 2010-02-18 1008 ret = -EFAULT; 6fe3faf86757eb drivers/net/tap.c Sainath Grandhi 2017-02-10 1009 tap_put_tap_dev(tap); 441ac0fcaadc76 drivers/net/macvtap.c Vlad Yasevich 2013-06-25 1010 rtnl_unlock(); 02df55d28c6001 drivers/net/macvtap.c Arnd Bergmann 2010-02-18 1011 return ret; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1012 815f236d622721 drivers/net/macvtap.c Jason Wang 2013-06-05 1013 case TUNSETQUEUE: 815f236d622721 drivers/net/macvtap.c Jason Wang 2013-06-05 1014 if (get_user(u, &ifr->ifr_flags)) 815f236d622721 drivers/net/macvtap.c Jason Wang 2013-06-05 1015 return -EFAULT; 441ac0fcaadc76 drivers/net/macvtap.c Vlad Yasevich 2013-06-25 1016 rtnl_lock(); 635b8c8ecdd271 drivers/net/tap.c Sainath Grandhi 2017-02-10 1017 ret = tap_ioctl_set_queue(file, u); 441ac0fcaadc76 drivers/net/macvtap.c Vlad Yasevich 2013-06-25 1018 rtnl_unlock(); 82a19eb8c02ab9 drivers/net/macvtap.c Jason Wang 2013-07-16 1019 return ret; 815f236d622721 drivers/net/macvtap.c Jason Wang 2013-06-05 1020 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1021 case TUNGETFEATURES: 635b8c8ecdd271 drivers/net/tap.c Sainath Grandhi 2017-02-10 1022 if (put_user(IFF_TAP | IFF_NO_PI | TAP_IFFEATURES, up)) 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1023 return -EFAULT; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1024 return 0; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1025 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1026 case TUNSETSNDBUF: 3ea79249e81e5e drivers/net/macvtap.c Michael S. Tsirkin 2015-09-18 1027 if (get_user(s, sp)) 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1028 return -EFAULT; 93161922c658c7 drivers/net/tap.c Craig Gallek 2017-10-30 1029 if (s <= 0) 93161922c658c7 drivers/net/tap.c Craig Gallek 2017-10-30 1030 return -EINVAL; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1031 3ea79249e81e5e drivers/net/macvtap.c Michael S. Tsirkin 2015-09-18 1032 q->sk.sk_sndbuf = s; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1033 return 0; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1034 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1035 case TUNSETOFFLOAD: 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1036 /* let the user check for future flags */ 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1037 if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | 399e0827642f6a drivers/net/tap.c Andrew Melnychenko 2022-12-07 1038 TUN_F_TSO_ECN | TUN_F_UFO | 399e0827642f6a drivers/net/tap.c Andrew Melnychenko 2022-12-07 1039 TUN_F_USO4 | TUN_F_USO6)) 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1040 return -EINVAL; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1041 2be5c76794b0e5 drivers/net/macvtap.c Vlad Yasevich 2013-06-25 1042 rtnl_lock(); 2be5c76794b0e5 drivers/net/macvtap.c Vlad Yasevich 2013-06-25 1043 ret = set_offload(q, arg); 2be5c76794b0e5 drivers/net/macvtap.c Vlad Yasevich 2013-06-25 1044 rtnl_unlock(); 2be5c76794b0e5 drivers/net/macvtap.c Vlad Yasevich 2013-06-25 1045 return ret; 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1046 2c592c9b450ea4 drivers/net/tap.c Akihiko Odaki 2025-03-06 1047 case TUNGETVNETHASHCAP: 2c592c9b450ea4 drivers/net/tap.c Akihiko Odaki 2025-03-06 1048 return tun_vnet_ioctl_gethashcap(argp); 2c592c9b450ea4 drivers/net/tap.c Akihiko Odaki 2025-03-06 1049 2c592c9b450ea4 drivers/net/tap.c Akihiko Odaki 2025-03-06 1050 case TUNSETVNETHASH: 2c592c9b450ea4 drivers/net/tap.c Akihiko Odaki 2025-03-06 1051 rtnl_lock(); 2c592c9b450ea4 drivers/net/tap.c Akihiko Odaki 2025-03-06 1052 tap = rtnl_dereference(q->tap); 2c592c9b450ea4 drivers/net/tap.c Akihiko Odaki 2025-03-06 1053 ret = tap ? tun_vnet_ioctl_sethash(&tap->vnet_hash, true, argp) : -EBADFD; 2c592c9b450ea4 drivers/net/tap.c Akihiko Odaki 2025-03-06 1054 rtnl_unlock(); 2c592c9b450ea4 drivers/net/tap.c Akihiko Odaki 2025-03-06 1055 b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 @1056 case SIOCGIFHWADDR: b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1057 rtnl_lock(); 6fe3faf86757eb drivers/net/tap.c Sainath Grandhi 2017-02-10 1058 tap = tap_get_tap_dev(q); 6fe3faf86757eb drivers/net/tap.c Sainath Grandhi 2017-02-10 1059 if (!tap) { b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1060 rtnl_unlock(); b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1061 return -ENOLINK; b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1062 } b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1063 ret = 0; 3b23a32a63219f drivers/net/tap.c Cong Wang 2021-02-11 1064 dev_get_mac_address(&sa, dev_net(tap->dev), tap->dev->name); 6fe3faf86757eb drivers/net/tap.c Sainath Grandhi 2017-02-10 1065 if (copy_to_user(&ifr->ifr_name, tap->dev->name, IFNAMSIZ) || 3b23a32a63219f drivers/net/tap.c Cong Wang 2021-02-11 1066 copy_to_user(&ifr->ifr_hwaddr, &sa, sizeof(sa))) b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1067 ret = -EFAULT; 6fe3faf86757eb drivers/net/tap.c Sainath Grandhi 2017-02-10 1068 tap_put_tap_dev(tap); b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1069 rtnl_unlock(); b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1070 return ret; b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1071 b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1072 case SIOCSIFHWADDR: 7f460d30c8e130 drivers/net/macvtap.c Justin Cormack 2015-05-13 1073 if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa))) 7f460d30c8e130 drivers/net/macvtap.c Justin Cormack 2015-05-13 1074 return -EFAULT; b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1075 rtnl_lock(); 6fe3faf86757eb drivers/net/tap.c Sainath Grandhi 2017-02-10 1076 tap = tap_get_tap_dev(q); 6fe3faf86757eb drivers/net/tap.c Sainath Grandhi 2017-02-10 1077 if (!tap) { b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1078 rtnl_unlock(); b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1079 return -ENOLINK; b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1080 } 3b23a32a63219f drivers/net/tap.c Cong Wang 2021-02-11 1081 ret = dev_set_mac_address_user(tap->dev, &sa, NULL); 6fe3faf86757eb drivers/net/tap.c Sainath Grandhi 2017-02-10 1082 tap_put_tap_dev(tap); b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1083 rtnl_unlock(); b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1084 return ret; b5082083392224 drivers/net/macvtap.c Justin Cormack 2015-05-11 1085 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1086 default: 69113cb5de68da drivers/net/tap.c Akihiko Odaki 2025-02-07 1087 return tun_vnet_ioctl(&q->vnet_hdr_sz, &q->flags, cmd, sp); 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1088 } 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1089 } 20d29d7a916a47 drivers/net/macvtap.c Arnd Bergmann 2010-01-30 1090
Ensure that vnet ioctls result in EBADFD when the underlying device is deleted.
Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com --- tools/testing/selftests/net/tun.c | 74 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+)
diff --git a/tools/testing/selftests/net/tun.c b/tools/testing/selftests/net/tun.c index fa83918b62d1be1c93adcd6c2f07654893cf97f8..463dd98f2b80b1bdcb398cee43c834e7dc5cf784 100644 --- a/tools/testing/selftests/net/tun.c +++ b/tools/testing/selftests/net/tun.c @@ -159,4 +159,78 @@ TEST_F(tun, reattach_close_delete) { EXPECT_EQ(tun_delete(self->ifname), 0); }
+FIXTURE(tun_deleted) +{ + char ifname[IFNAMSIZ]; + int fd; +}; + +FIXTURE_SETUP(tun_deleted) +{ + self->ifname[0] = 0; + self->fd = tun_alloc(self->ifname); + ASSERT_LE(0, self->fd); + + ASSERT_EQ(0, tun_delete(self->ifname)) + EXPECT_EQ(0, close(self->fd)); +} + +FIXTURE_TEARDOWN(tun_deleted) +{ + EXPECT_EQ(0, close(self->fd)); +} + +TEST_F(tun_deleted, getvnethdrsz) +{ + ASSERT_EQ(-1, ioctl(self->fd, TUNGETVNETHDRSZ)); + EXPECT_EQ(EBADFD, errno); +} + +TEST_F(tun_deleted, setvnethdrsz) +{ + ASSERT_EQ(-1, ioctl(self->fd, TUNSETVNETHDRSZ)); + EXPECT_EQ(EBADFD, errno); +} + +TEST_F(tun_deleted, getvnetle) +{ + ASSERT_EQ(-1, ioctl(self->fd, TUNGETVNETLE)); + EXPECT_EQ(EBADFD, errno); +} + +TEST_F(tun_deleted, setvnetle) +{ + ASSERT_EQ(-1, ioctl(self->fd, TUNSETVNETLE)); + EXPECT_EQ(EBADFD, errno); +} + +TEST_F(tun_deleted, getvnetbe) +{ + ASSERT_EQ(-1, ioctl(self->fd, TUNGETVNETBE)); + EXPECT_EQ(EBADFD, errno); +} + +TEST_F(tun_deleted, setvnetbe) +{ + ASSERT_EQ(-1, ioctl(self->fd, TUNSETVNETBE)); + EXPECT_EQ(EBADFD, errno); +} + +TEST_F(tun_deleted, getvnethashcap) +{ + struct tun_vnet_hash cap; + int i = ioctl(self->fd, TUNGETVNETHASHCAP, &cap); + + if (i == -1 && errno == EBADFD) + SKIP(return, "TUNGETVNETHASHCAP not supported"); + + EXPECT_EQ(0, i); +} + +TEST_F(tun_deleted, setvnethash) +{ + ASSERT_EQ(-1, ioctl(self->fd, TUNSETVNETHASH)); + EXPECT_EQ(EBADFD, errno); +} + TEST_HARNESS_MAIN
The added tests confirm tun can perform RSS and hash reporting, and reject invalid configurations for them.
Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com --- tools/testing/selftests/net/Makefile | 2 +- tools/testing/selftests/net/tun.c | 584 ++++++++++++++++++++++++++++++++++- 2 files changed, 576 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index 73ee88d6b043004be23b444de667a1d99a6045de..9772f691a9a011d99212df32463cdb930cf0a1a0 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -123,6 +123,6 @@ $(OUTPUT)/reuseport_bpf_numa: LDLIBS += -lnuma $(OUTPUT)/tcp_mmap: LDLIBS += -lpthread -lcrypto $(OUTPUT)/tcp_inq: LDLIBS += -lpthread $(OUTPUT)/bind_bhash: LDLIBS += -lpthread -$(OUTPUT)/io_uring_zerocopy_tx: CFLAGS += -I../../../include/ +$(OUTPUT)/io_uring_zerocopy_tx $(OUTPUT)/tun: CFLAGS += -I../../../include/
include bpf.mk diff --git a/tools/testing/selftests/net/tun.c b/tools/testing/selftests/net/tun.c index 463dd98f2b80b1bdcb398cee43c834e7dc5cf784..acadeea7194eaea9416a605b47f99f7a5f1f80cd 100644 --- a/tools/testing/selftests/net/tun.c +++ b/tools/testing/selftests/net/tun.c @@ -2,21 +2,38 @@
#define _GNU_SOURCE
+#include <endian.h> #include <errno.h> #include <fcntl.h> +#include <sched.h> +#include <stddef.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> -#include <linux/if.h> +#include <net/if.h> +#include <netinet/ip.h> +#include <sys/ioctl.h> +#include <sys/socket.h> +#include <linux/compiler.h> +#include <linux/icmp.h> +#include <linux/if_arp.h> #include <linux/if_tun.h> +#include <linux/ipv6.h> #include <linux/netlink.h> #include <linux/rtnetlink.h> -#include <sys/ioctl.h> -#include <sys/socket.h> +#include <linux/sockios.h> +#include <linux/tcp.h> +#include <linux/udp.h> +#include <linux/virtio_net.h>
#include "../kselftest_harness.h"
+#define TUN_HWADDR_SOURCE { 0x02, 0x00, 0x00, 0x00, 0x00, 0x00 } +#define TUN_HWADDR_DEST { 0x02, 0x00, 0x00, 0x00, 0x00, 0x01 } +#define TUN_IPADDR_SOURCE htonl((172 << 24) | (17 << 16) | 0) +#define TUN_IPADDR_DEST htonl((172 << 24) | (17 << 16) | 1) + static int tun_attach(int fd, char *dev) { struct ifreq ifr; @@ -39,7 +56,7 @@ static int tun_detach(int fd, char *dev) return ioctl(fd, TUNSETQUEUE, (void *) &ifr); }
-static int tun_alloc(char *dev) +static int tun_alloc(char *dev, short flags) { struct ifreq ifr; int fd, err; @@ -52,7 +69,8 @@ static int tun_alloc(char *dev)
memset(&ifr, 0, sizeof(ifr)); strcpy(ifr.ifr_name, dev); - ifr.ifr_flags = IFF_TAP | IFF_NAPI | IFF_MULTI_QUEUE; + ifr.ifr_flags = flags | IFF_TAP | IFF_NAPI | IFF_NO_PI | + IFF_MULTI_QUEUE;
err = ioctl(fd, TUNSETIFF, (void *) &ifr); if (err < 0) { @@ -64,6 +82,40 @@ static int tun_alloc(char *dev) return fd; }
+static bool tun_add_to_bridge(int local_fd, const char *name) +{ + struct ifreq ifreq = { + .ifr_name = "xbridge", + .ifr_ifindex = if_nametoindex(name) + }; + + if (!ifreq.ifr_ifindex) { + perror("if_nametoindex"); + return false; + } + + if (ioctl(local_fd, SIOCBRADDIF, &ifreq)) { + perror("SIOCBRADDIF"); + return false; + } + + return true; +} + +static bool tun_set_flags(int local_fd, const char *name, short flags) +{ + struct ifreq ifreq = { .ifr_flags = flags }; + + strcpy(ifreq.ifr_name, name); + + if (ioctl(local_fd, SIOCSIFFLAGS, &ifreq)) { + perror("SIOCSIFFLAGS"); + return false; + } + + return true; +} + static int tun_delete(char *dev) { struct { @@ -102,6 +154,156 @@ static int tun_delete(char *dev) return ret; }
+static uint32_t tun_sum(const void *buf, size_t len) +{ + const uint16_t *sbuf = buf; + uint32_t sum = 0; + + while (len > 1) { + sum += *sbuf++; + len -= 2; + } + + if (len) + sum += *(uint8_t *)sbuf; + + return sum; +} + +static uint16_t tun_build_ip_check(uint32_t sum) +{ + return ~((sum & 0xffff) + (sum >> 16)); +} + +static uint32_t tun_build_ip_pseudo_sum(const void *iphdr) +{ + uint16_t tot_len = ntohs(((struct iphdr *)iphdr)->tot_len); + + return tun_sum((char *)iphdr + offsetof(struct iphdr, saddr), 8) + + htons(((struct iphdr *)iphdr)->protocol) + + htons(tot_len - sizeof(struct iphdr)); +} + +static uint32_t tun_build_ipv6_pseudo_sum(const void *ipv6hdr) +{ + return tun_sum((char *)ipv6hdr + offsetof(struct ipv6hdr, saddr), 32) + + ((struct ipv6hdr *)ipv6hdr)->payload_len + + htons(((struct ipv6hdr *)ipv6hdr)->nexthdr); +} + +static void tun_build_ethhdr(struct ethhdr *ethhdr, uint16_t proto) +{ + *ethhdr = (struct ethhdr) { + .h_dest = TUN_HWADDR_DEST, + .h_source = TUN_HWADDR_SOURCE, + .h_proto = htons(proto) + }; +} + +static void tun_build_iphdr(void *dest, uint16_t len, uint8_t protocol) +{ + struct iphdr iphdr = { + .ihl = sizeof(iphdr) / 4, + .version = 4, + .tot_len = htons(sizeof(iphdr) + len), + .ttl = 255, + .protocol = protocol, + .saddr = TUN_IPADDR_SOURCE, + .daddr = TUN_IPADDR_DEST + }; + + iphdr.check = tun_build_ip_check(tun_sum(&iphdr, sizeof(iphdr))); + memcpy(dest, &iphdr, sizeof(iphdr)); +} + +static void tun_build_ipv6hdr(void *dest, uint16_t len, uint8_t protocol) +{ + struct ipv6hdr ipv6hdr = { + .version = 6, + .payload_len = htons(len), + .nexthdr = protocol, + .saddr = { + .s6_addr32 = { + htonl(0xffff0000), 0, 0, TUN_IPADDR_SOURCE + } + }, + .daddr = { + .s6_addr32 = { + htonl(0xffff0000), 0, 0, TUN_IPADDR_DEST + } + }, + }; + + memcpy(dest, &ipv6hdr, sizeof(ipv6hdr)); +} + +static void tun_build_tcphdr(void *dest, uint32_t sum) +{ + struct tcphdr tcphdr = { + .source = htons(9), + .dest = htons(9), + .fin = 1, + .doff = sizeof(tcphdr) / 4, + }; + uint32_t tcp_sum = tun_sum(&tcphdr, sizeof(tcphdr)); + + tcphdr.check = tun_build_ip_check(sum + tcp_sum); + memcpy(dest, &tcphdr, sizeof(tcphdr)); +} + +static void tun_build_udphdr(void *dest, uint32_t sum) +{ + struct udphdr udphdr = { + .source = htons(9), + .dest = htons(9), + .len = htons(sizeof(udphdr)), + }; + uint32_t udp_sum = tun_sum(&udphdr, sizeof(udphdr)); + + udphdr.check = tun_build_ip_check(sum + udp_sum); + memcpy(dest, &udphdr, sizeof(udphdr)); +} + +static bool tun_vnet_hash_check(int source_fd, const int *dest_fds, + const void *buffer, size_t len, + uint8_t flags, + uint16_t hash_report, uint32_t hash_value) +{ + size_t read_len = sizeof(struct virtio_net_hdr_v1_hash) + len; + struct virtio_net_hdr_v1_hash *read_buffer; + struct virtio_net_hdr_v1_hash hdr = { + .hdr = { .flags = flags }, + .hash_value = htole32(hash_value), + .hash_report = htole16(hash_report) + }; + int ret; + int txq = hash_report ? hash_value & 1 : 2; + + if (write(source_fd, buffer, len) != len) { + perror("write"); + return false; + } + + read_buffer = malloc(read_len); + if (!read_buffer) { + perror("malloc"); + return false; + } + + ret = read(dest_fds[txq], read_buffer, read_len); + if (ret != read_len) { + perror("read"); + free(read_buffer); + return false; + } + + ret = !memcmp(read_buffer, &hdr, sizeof(*read_buffer)) && + !memcmp(read_buffer + 1, buffer, len); + + free(read_buffer); + return ret; +} + FIXTURE(tun) { char ifname[IFNAMSIZ]; @@ -112,10 +314,10 @@ FIXTURE_SETUP(tun) { memset(self->ifname, 0, sizeof(self->ifname));
- self->fd = tun_alloc(self->ifname); + self->fd = tun_alloc(self->ifname, 0); ASSERT_GE(self->fd, 0);
- self->fd2 = tun_alloc(self->ifname); + self->fd2 = tun_alloc(self->ifname, 0); ASSERT_GE(self->fd2, 0); }
@@ -168,7 +370,7 @@ FIXTURE(tun_deleted) FIXTURE_SETUP(tun_deleted) { self->ifname[0] = 0; - self->fd = tun_alloc(self->ifname); + self->fd = tun_alloc(self->ifname, 0); ASSERT_LE(0, self->fd);
ASSERT_EQ(0, tun_delete(self->ifname)) @@ -233,4 +435,368 @@ TEST_F(tun_deleted, setvnethash) EXPECT_EQ(EBADFD, errno); }
-TEST_HARNESS_MAIN +FIXTURE(tun_vnet_hash) +{ + int local_fd; + int source_fd; + int dest_fds[3]; +}; + +FIXTURE_SETUP(tun_vnet_hash) +{ + static const struct { + struct tun_vnet_hash hdr; + struct tun_vnet_hash_rss rss; + uint16_t rss_indirection_table[2]; + uint8_t rss_key[40]; + } vnet_hash = { + .hdr = { + .flags = TUN_VNET_HASH_REPORT | TUN_VNET_HASH_RSS, + .types = VIRTIO_NET_RSS_HASH_TYPE_IPv4 | + VIRTIO_NET_RSS_HASH_TYPE_TCPv4 | + VIRTIO_NET_RSS_HASH_TYPE_UDPv4 | + VIRTIO_NET_RSS_HASH_TYPE_IPv6 | + VIRTIO_NET_RSS_HASH_TYPE_TCPv6 | + VIRTIO_NET_RSS_HASH_TYPE_UDPv6 + }, + .rss = { .indirection_table_mask = 1, .unclassified_queue = 5 }, + .rss_indirection_table = { 3, 4 }, + .rss_key = { + 0x6d, 0x5a, 0x56, 0xda, 0x25, 0x5b, 0x0e, 0xc2, + 0x41, 0x67, 0x25, 0x3d, 0x43, 0xa3, 0x8f, 0xb0, + 0xd0, 0xca, 0x2b, 0xcb, 0xae, 0x7b, 0x30, 0xb4, + 0x77, 0xcb, 0x2d, 0xa3, 0x80, 0x30, 0xf2, 0x0c, + 0x6a, 0x42, 0xb7, 0x3b, 0xbe, 0xac, 0x01, 0xfa + } + }; + + struct { + struct virtio_net_hdr_v1_hash vnet_hdr; + struct ethhdr ethhdr; + struct arphdr arphdr; + unsigned char sender_hwaddr[6]; + uint32_t sender_ipaddr; + unsigned char target_hwaddr[6]; + uint32_t target_ipaddr; + } __packed packet = { + .ethhdr = { + .h_source = TUN_HWADDR_SOURCE, + .h_dest = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }, + .h_proto = htons(ETH_P_ARP) + }, + .arphdr = { + .ar_hrd = htons(ARPHRD_ETHER), + .ar_pro = htons(ETH_P_IP), + .ar_hln = ETH_ALEN, + .ar_pln = 4, + .ar_op = htons(ARPOP_REQUEST) + }, + .sender_hwaddr = TUN_HWADDR_DEST, + .sender_ipaddr = TUN_IPADDR_DEST, + .target_ipaddr = TUN_IPADDR_DEST + }; + + struct tun_vnet_hash cap; + char source_ifname[IFNAMSIZ] = ""; + char dest_ifname[IFNAMSIZ] = ""; + int i; + + self->local_fd = socket(AF_LOCAL, SOCK_STREAM, 0); + ASSERT_LE(0, self->local_fd); + + self->source_fd = tun_alloc(source_ifname, 0); + ASSERT_LE(0, self->source_fd) { + EXPECT_EQ(0, close(self->local_fd)); + } + + i = ioctl(self->source_fd, TUNGETVNETHASHCAP, &cap); + if (i == -1 && errno == EINVAL) { + EXPECT_EQ(0, close(self->local_fd)); + SKIP(return, "TUNGETVNETHASHCAP not supported"); + } + + ASSERT_EQ(0, i) + EXPECT_EQ(0, close(self->local_fd)); + + if ((cap.flags & vnet_hash.hdr.flags) != vnet_hash.hdr.flags) { + EXPECT_EQ(0, close(self->local_fd)); + SKIP(return, "Lacks some hash flag support"); + } + + if ((cap.types & vnet_hash.hdr.types) != vnet_hash.hdr.types) { + EXPECT_EQ(0, close(self->local_fd)); + SKIP(return, "Lacks some hash type support"); + } + + ASSERT_TRUE(tun_set_flags(self->local_fd, source_ifname, IFF_UP)) + EXPECT_EQ(0, close(self->local_fd)); + + self->dest_fds[0] = tun_alloc(dest_ifname, IFF_VNET_HDR); + ASSERT_LE(0, self->dest_fds[0]) { + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); + } + + i = sizeof(struct virtio_net_hdr_v1_hash); + ASSERT_EQ(0, ioctl(self->dest_fds[0], TUNSETVNETHDRSZ, &i)) { + EXPECT_EQ(0, close(self->dest_fds[0])); + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); + } + + i = 1; + ASSERT_EQ(0, ioctl(self->dest_fds[0], TUNSETVNETLE, &i)) { + EXPECT_EQ(0, close(self->dest_fds[0])); + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); + } + + ASSERT_TRUE(tun_set_flags(self->local_fd, dest_ifname, IFF_UP)) { + EXPECT_EQ(0, close(self->dest_fds[0])); + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); + } + + ASSERT_EQ(sizeof(packet), + write(self->dest_fds[0], &packet, sizeof(packet))) { + EXPECT_EQ(0, close(self->dest_fds[0])); + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); + } + + ASSERT_EQ(0, ioctl(self->dest_fds[0], TUNSETVNETHASH, &vnet_hash)) { + EXPECT_EQ(0, close(self->dest_fds[0])); + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); + } + + for (i = 1; i < ARRAY_SIZE(self->dest_fds); i++) { + self->dest_fds[i] = tun_alloc(dest_ifname, IFF_VNET_HDR); + ASSERT_LE(0, self->dest_fds[i]) { + while (i) { + i--; + EXPECT_EQ(0, close(self->local_fd)); + } + + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); + } + } + + ASSERT_EQ(0, ioctl(self->local_fd, SIOCBRADDBR, "xbridge")) { + EXPECT_EQ(0, ioctl(self->local_fd, SIOCBRDELBR, "xbridge")); + + for (i = 0; i < ARRAY_SIZE(self->dest_fds); i++) + EXPECT_EQ(0, close(self->dest_fds[i])); + + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); + } + + ASSERT_TRUE(tun_add_to_bridge(self->local_fd, source_ifname)) { + EXPECT_EQ(0, ioctl(self->local_fd, SIOCBRDELBR, "xbridge")); + + for (i = 0; i < ARRAY_SIZE(self->dest_fds); i++) + EXPECT_EQ(0, close(self->dest_fds[i])); + + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); + } + + ASSERT_TRUE(tun_add_to_bridge(self->local_fd, dest_ifname)) { + EXPECT_EQ(0, ioctl(self->local_fd, SIOCBRDELBR, "xbridge")); + + for (i = 0; i < ARRAY_SIZE(self->dest_fds); i++) + EXPECT_EQ(0, close(self->dest_fds[i])); + + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); + } + + ASSERT_TRUE(tun_set_flags(self->local_fd, "xbridge", IFF_UP)) { + EXPECT_EQ(0, ioctl(self->local_fd, SIOCBRDELBR, "xbridge")); + + for (i = 0; i < ARRAY_SIZE(self->dest_fds); i++) + EXPECT_EQ(0, close(self->dest_fds[i])); + + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); + } +} + +FIXTURE_TEARDOWN(tun_vnet_hash) +{ + ASSERT_TRUE(tun_set_flags(self->local_fd, "xbridge", 0)) { + for (size_t i = 0; i < ARRAY_SIZE(self->dest_fds); i++) + EXPECT_EQ(0, close(self->dest_fds[i])); + + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); + } + + EXPECT_EQ(0, ioctl(self->local_fd, SIOCBRDELBR, "xbridge")); + + for (size_t i = 0; i < ARRAY_SIZE(self->dest_fds); i++) + EXPECT_EQ(0, close(self->dest_fds[i])); + + EXPECT_EQ(0, close(self->source_fd)); + EXPECT_EQ(0, close(self->local_fd)); +} + +TEST_F(tun_vnet_hash, unclassified) +{ + struct { + struct ethhdr ethhdr; + struct iphdr iphdr; + } __packed packet; + + tun_build_ethhdr(&packet.ethhdr, ETH_P_LOOPBACK); + + EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds, + &packet, sizeof(packet), 0, + VIRTIO_NET_HASH_REPORT_NONE, 0)); +} + +TEST_F(tun_vnet_hash, ipv4) +{ + struct { + struct ethhdr ethhdr; + struct iphdr iphdr; + } __packed packet; + + tun_build_ethhdr(&packet.ethhdr, ETH_P_IP); + tun_build_iphdr(&packet.iphdr, 0, 253); + + EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds, + &packet, sizeof(packet), 0, + VIRTIO_NET_HASH_REPORT_IPv4, + 0x6e45d952)); +} + +TEST_F(tun_vnet_hash, tcpv4) +{ + struct { + struct ethhdr ethhdr; + struct iphdr iphdr; + struct tcphdr tcphdr; + } __packed packet; + + tun_build_ethhdr(&packet.ethhdr, ETH_P_IP); + tun_build_iphdr(&packet.iphdr, sizeof(struct tcphdr), IPPROTO_TCP); + + tun_build_tcphdr(&packet.tcphdr, + tun_build_ip_pseudo_sum(&packet.iphdr)); + + EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds, + &packet, sizeof(packet), + VIRTIO_NET_HDR_F_DATA_VALID, + VIRTIO_NET_HASH_REPORT_TCPv4, + 0xfb63539a)); +} + +TEST_F(tun_vnet_hash, udpv4) +{ + struct { + struct ethhdr ethhdr; + struct iphdr iphdr; + struct udphdr udphdr; + } __packed packet; + + tun_build_ethhdr(&packet.ethhdr, ETH_P_IP); + tun_build_iphdr(&packet.iphdr, sizeof(struct udphdr), IPPROTO_UDP); + + tun_build_udphdr(&packet.udphdr, + tun_build_ip_pseudo_sum(&packet.iphdr)); + + EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds, + &packet, sizeof(packet), + VIRTIO_NET_HDR_F_DATA_VALID, + VIRTIO_NET_HASH_REPORT_UDPv4, + 0xfb63539a)); +} + +TEST_F(tun_vnet_hash, ipv6) +{ + struct { + struct ethhdr ethhdr; + struct ipv6hdr ipv6hdr; + } __packed packet; + + tun_build_ethhdr(&packet.ethhdr, ETH_P_IPV6); + tun_build_ipv6hdr(&packet.ipv6hdr, 0, 253); + + EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds, + &packet, sizeof(packet), 0, + VIRTIO_NET_HASH_REPORT_IPv6, + 0xd6eb560f)); +} + +TEST_F(tun_vnet_hash, tcpv6) +{ + struct { + struct ethhdr ethhdr; + struct ipv6hdr ipv6hdr; + struct tcphdr tcphdr; + } __packed packet; + + tun_build_ethhdr(&packet.ethhdr, ETH_P_IPV6); + tun_build_ipv6hdr(&packet.ipv6hdr, sizeof(struct tcphdr), IPPROTO_TCP); + + tun_build_tcphdr(&packet.tcphdr, + tun_build_ipv6_pseudo_sum(&packet.ipv6hdr)); + + EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds, + &packet, sizeof(packet), + VIRTIO_NET_HDR_F_DATA_VALID, + VIRTIO_NET_HASH_REPORT_TCPv6, + 0xc2b9f251)); +} + +TEST_F(tun_vnet_hash, udpv6) +{ + struct { + struct ethhdr ethhdr; + struct ipv6hdr ipv6hdr; + struct udphdr udphdr; + } __packed packet; + + tun_build_ethhdr(&packet.ethhdr, ETH_P_IPV6); + tun_build_ipv6hdr(&packet.ipv6hdr, sizeof(struct udphdr), IPPROTO_UDP); + + tun_build_udphdr(&packet.udphdr, + tun_build_ipv6_pseudo_sum(&packet.ipv6hdr)); + + EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds, + &packet, sizeof(packet), + VIRTIO_NET_HDR_F_DATA_VALID, + VIRTIO_NET_HASH_REPORT_UDPv6, + 0xc2b9f251)); +} + +int main(int argc, char **argv) +{ + FILE *file; + + if (unshare(CLONE_NEWNET)) { + perror("unshare"); + return KSFT_FAIL; + } + + file = fopen("/proc/sys/net/ipv6/conf/default/disable_ipv6", "w"); + if (file) { + if (fputc('1', file) != '1') { + perror("fputc"); + return KSFT_FAIL; + } + + if (fclose(file)) { + perror("fclose"); + return KSFT_FAIL; + } + } else if (errno != ENOENT) { + perror("fopen"); + return KSFT_FAIL; + } + + return test_harness_run(argc, argv); +}
VIRTIO_NET_F_HASH_REPORT allows to report hash values calculated on the host. When VHOST_NET_F_VIRTIO_NET_HDR is employed, it will report no hash values (i.e., the hash_report member is always set to VIRTIO_NET_HASH_REPORT_NONE). Otherwise, the values reported by the underlying socket will be reported.
VIRTIO_NET_F_HASH_REPORT requires VIRTIO_F_VERSION_1.
Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com --- drivers/vhost/net.c | 49 +++++++++++++++++++++++++++++-------------------- 1 file changed, 29 insertions(+), 20 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index b9b9e9d40951856d881d77ac74331d914473cd56..16b241b44f89820a42c302f3586ea6bb5e0d4289 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -73,6 +73,7 @@ enum { VHOST_NET_FEATURES = VHOST_FEATURES | (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | (1ULL << VIRTIO_NET_F_MRG_RXBUF) | + (1ULL << VIRTIO_NET_F_HASH_REPORT) | (1ULL << VIRTIO_F_ACCESS_PLATFORM) | (1ULL << VIRTIO_F_RING_RESET) }; @@ -1097,9 +1098,11 @@ static void handle_rx(struct vhost_net *net) .msg_controllen = 0, .msg_flags = MSG_DONTWAIT, }; - struct virtio_net_hdr hdr = { - .flags = 0, - .gso_type = VIRTIO_NET_HDR_GSO_NONE + struct virtio_net_hdr_v1_hash hdr = { + .hdr = { + .flags = 0, + .gso_type = VIRTIO_NET_HDR_GSO_NONE + } }; size_t total_len = 0; int err, mergeable; @@ -1110,7 +1113,6 @@ static void handle_rx(struct vhost_net *net) bool set_num_buffers; struct socket *sock; struct iov_iter fixup; - __virtio16 num_buffers; int recv_pkts = 0;
mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX); @@ -1191,30 +1193,30 @@ static void handle_rx(struct vhost_net *net) vhost_discard_vq_desc(vq, headcount); continue; } + hdr.hdr.num_buffers = cpu_to_vhost16(vq, headcount); /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */ if (unlikely(vhost_hlen)) { - if (copy_to_iter(&hdr, sizeof(hdr), - &fixup) != sizeof(hdr)) { + if (copy_to_iter(&hdr, vhost_hlen, + &fixup) != vhost_hlen) { vq_err(vq, "Unable to write vnet_hdr " "at addr %p\n", vq->iov->iov_base); goto out; } - } else { + } else if (likely(set_num_buffers)) { /* Header came from socket; we'll need to patch * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF */ - iov_iter_advance(&fixup, sizeof(hdr)); + iov_iter_advance(&fixup, offsetof(struct virtio_net_hdr_v1, num_buffers)); + + if (copy_to_iter(&hdr.hdr.num_buffers, sizeof(hdr.hdr.num_buffers), + &fixup) != sizeof(hdr.hdr.num_buffers)) { + vq_err(vq, "Failed num_buffers write"); + vhost_discard_vq_desc(vq, headcount); + goto out; + } } /* TODO: Should check and handle checksum. */
- num_buffers = cpu_to_vhost16(vq, headcount); - if (likely(set_num_buffers) && - copy_to_iter(&num_buffers, sizeof num_buffers, - &fixup) != sizeof num_buffers) { - vq_err(vq, "Failed num_buffers write"); - vhost_discard_vq_desc(vq, headcount); - goto out; - } nvq->done_idx += headcount; if (nvq->done_idx > VHOST_NET_BATCH) vhost_net_signal_used(nvq); @@ -1607,10 +1609,13 @@ static int vhost_net_set_features(struct vhost_net *n, u64 features) size_t vhost_hlen, sock_hlen, hdr_len; int i;
- hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | - (1ULL << VIRTIO_F_VERSION_1))) ? - sizeof(struct virtio_net_hdr_mrg_rxbuf) : - sizeof(struct virtio_net_hdr); + if (features & (1ULL << VIRTIO_NET_F_HASH_REPORT)) + hdr_len = sizeof(struct virtio_net_hdr_v1_hash); + else if (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | + (1ULL << VIRTIO_F_VERSION_1))) + hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf); + else + hdr_len = sizeof(struct virtio_net_hdr); if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { /* vhost provides vnet_hdr */ vhost_hlen = hdr_len; @@ -1691,6 +1696,10 @@ static long vhost_net_ioctl(struct file *f, unsigned int ioctl, return -EFAULT; if (features & ~VHOST_NET_FEATURES) return -EOPNOTSUPP; + if ((features & ((1ULL << VIRTIO_F_VERSION_1) | + (1ULL << VIRTIO_NET_F_HASH_REPORT))) == + (1ULL << VIRTIO_NET_F_HASH_REPORT)) + return -EINVAL; return vhost_net_set_features(n, features); case VHOST_GET_BACKEND_FEATURES: features = VHOST_NET_BACKEND_FEATURES;
QE tested this series of patches with virtio-net regression tests, everything works fine.
Tested-by: Lei Yang leiyang@redhat.com
On Thu, Mar 6, 2025 at 5:57 PM Akihiko Odaki akihiko.odaki@daynix.com wrote:
virtio-net have two usage of hashes: one is RSS and another is hash reporting. Conventionally the hash calculation was done by the VMM. However, computing the hash after the queue was chosen defeats the purpose of RSS.
Another approach is to use eBPF steering program. This approach has another downside: it cannot report the calculated hash due to the restrictive nature of eBPF.
Introduce the code to compute hashes to the kernel in order to overcome thse challenges.
An alternative solution is to extend the eBPF steering program so that it will be able to report to the userspace, but it is based on context rewrites, which is in feature freeze. We can adopt kfuncs, but they will not be UAPIs. We opt to ioctl to align with other relevant UAPIs (KVM and vhost_net).
The patches for QEMU to use this new feature was submitted as RFC and is available at: https://patchew.org/QEMU/20240915-hash-v3-0-79cb08d28647@daynix.com/
This work was presented at LPC 2024: https://lpc.events/event/18/contributions/1963/
V1 -> V2: Changed to introduce a new BPF program type.
Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com
Changes in v8:
- Disabled IPv6 to eliminate noises in tests.
- Added a branch in tap to avoid unnecessary dissection when hash reporting is disabled.
- Removed unnecessary rtnl_lock().
- Extracted code to handle new ioctls into separate functions to avoid adding extra NULL checks to the code handling other ioctls.
- Introduced variable named "fd" to __tun_chr_ioctl().
- s/-/=/g in a patch message to avoid confusing Git.
- Link to v7: https://lore.kernel.org/r/20250228-rss-v7-0-844205cbbdd6@daynix.com
Changes in v7:
- Ensured to set hash_report to VIRTIO_NET_HASH_REPORT_NONE for VHOST_NET_F_VIRTIO_NET_HDR.
- s/4/sizeof(u32)/ in patch "virtio_net: Add functions for hashing".
- Added tap_skb_cb type.
- Rebased.
- Link to v6: https://lore.kernel.org/r/20250109-rss-v6-0-b1c90ad708f6@daynix.com
Changes in v6:
- Extracted changes to fill vnet header holes into another series.
- Squashed patches "skbuff: Introduce SKB_EXT_TUN_VNET_HASH", "tun: Introduce virtio-net hash reporting feature", and "tun: Introduce virtio-net RSS" into patch "tun: Introduce virtio-net hash feature".
- Dropped the RFC tag.
- Link to v5: https://lore.kernel.org/r/20241008-rss-v5-0-f3cf68df005d@daynix.com
Changes in v5:
- Fixed a compilation error with CONFIG_TUN_VNET_CROSS_LE.
- Optimized the calculation of the hash value according to: https://git.dpdk.org/dpdk/commit/?id=3fb1ea032bd6ff8317af5dac9af901f1f324cab...
- Added patch "tun: Unify vnet implementation".
- Dropped patch "tap: Pad virtio header with zero".
- Added patch "selftest: tun: Test vnet ioctls without device".
- Reworked selftests to skip for older kernels.
- Documented the case when the underlying device is deleted and packets have queue_mapping set by TC.
- Reordered test harness arguments.
- Added code to handle fragmented packets.
- Link to v4: https://lore.kernel.org/r/20240924-rss-v4-0-84e932ec0e6c@daynix.com
Changes in v4:
- Moved tun_vnet_hash_ext to if_tun.h.
- Renamed virtio_net_toeplitz() to virtio_net_toeplitz_calc().
- Replaced htons() with cpu_to_be16().
- Changed virtio_net_hash_rss() to return void.
- Reordered variable declarations in virtio_net_hash_rss().
- Removed virtio_net_hdr_v1_hash_from_skb().
- Updated messages of "tap: Pad virtio header with zero" and "tun: Pad virtio header with zero".
- Fixed vnet_hash allocation size.
- Ensured to free vnet_hash when destructing tun_struct.
- Link to v3: https://lore.kernel.org/r/20240915-rss-v3-0-c630015db082@daynix.com
Changes in v3:
- Reverted back to add ioctl.
- Split patch "tun: Introduce virtio-net hashing feature" into "tun: Introduce virtio-net hash reporting feature" and "tun: Introduce virtio-net RSS".
- Changed to reuse hash values computed for automq instead of performing RSS hashing when hash reporting is requested but RSS is not.
- Extracted relevant data from struct tun_struct to keep it minimal.
- Added kernel-doc.
- Changed to allow calling TUNGETVNETHASHCAP before TUNSETIFF.
- Initialized num_buffers with 1.
- Added a test case for unclassified packets.
- Fixed error handling in tests.
- Changed tests to verify that the queue index will not overflow.
- Rebased.
- Link to v2: https://lore.kernel.org/r/20231015141644.260646-1-akihiko.odaki@daynix.com
Akihiko Odaki (6): virtio_net: Add functions for hashing net: flow_dissector: Export flow_keys_dissector_symmetric tun: Introduce virtio-net hash feature selftest: tun: Test vnet ioctls without device selftest: tun: Add tests for virtio-net hashing vhost/net: Support VIRTIO_NET_F_HASH_REPORT
Documentation/networking/tuntap.rst | 7 + drivers/net/Kconfig | 1 + drivers/net/tap.c | 67 +++- drivers/net/tun.c | 98 +++++- drivers/net/tun_vnet.h | 159 ++++++++- drivers/vhost/net.c | 49 +-- include/linux/if_tap.h | 2 + include/linux/skbuff.h | 3 + include/linux/virtio_net.h | 188 ++++++++++ include/net/flow_dissector.h | 1 + include/uapi/linux/if_tun.h | 75 ++++ net/core/flow_dissector.c | 3 +- net/core/skbuff.c | 4 + tools/testing/selftests/net/Makefile | 2 +- tools/testing/selftests/net/tun.c | 656 ++++++++++++++++++++++++++++++++++- 15 files changed, 1254 insertions(+), 61 deletions(-)
base-commit: dd83757f6e686a2188997cb58b5975f744bb7786 change-id: 20240403-rss-e737d89efa77 prerequisite-change-id: 20241230-tun-66e10a49b0c7:v6 prerequisite-patch-id: 871dc5f146fb6b0e3ec8612971a8e8190472c0fb prerequisite-patch-id: 2797ed249d32590321f088373d4055ff3f430a0e prerequisite-patch-id: ea3370c72d4904e2f0536ec76ba5d26784c0cede prerequisite-patch-id: 837e4cf5d6b451424f9b1639455e83a260c4440d prerequisite-patch-id: ea701076f57819e844f5a35efe5cbc5712d3080d prerequisite-patch-id: 701646fb43ad04cc64dd2bf13c150ccbe6f828ce prerequisite-patch-id: 53176dae0c003f5b6c114d43f936cf7140d31bb5 prerequisite-change-id: 20250116-buffers-96e14bf023fc:v2 prerequisite-patch-id: 25fd4f99d4236a05a5ef16ab79f3e85ee57e21cc
Best regards,
Akihiko Odaki akihiko.odaki@daynix.com
linux-kselftest-mirror@lists.linaro.org
-
Akihiko Odaki -
Jakub Kicinski -
kernel test robot -
Lei Yang