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 02a9f4dc594d..3b25ca75710b 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 + 4;
+}
+
+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) {
--
2.47.1Akihiko Odaki wrote:
> They are useful to implement VIRTIO_NET_F_RSS and
> VIRTIO_NET_F_HASH_REPORT.
Toeplitz potentially has users beyond virtio. I wonder if we should
from the start implement this as net/core/rss.c.
> 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 02a9f4dc594d..3b25ca75710b 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);
> + }
> +}
Have you verified that this algorithm matches a known toeplitz
implementation. And computes the expected values for the test
inputs in
https://learn.microsoft.com/en-us/windows-hardware/drivers/network/verifying-the-rss-hash-calculation
We have a toeplitz implementation in
tools/testing/selftests/net/toeplitz.c that can also be used as
reference.
> +
> +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 + 4;
Avoid magic constants. Please use sizeof or something else to signal
what this 4 derives from.
On 2025/01/09 23:13, Willem de Bruijn wrote:
> Akihiko Odaki wrote:
>> They are useful to implement VIRTIO_NET_F_RSS and
>> VIRTIO_NET_F_HASH_REPORT.
>
> Toeplitz potentially has users beyond virtio. I wonder if we should
> from the start implement this as net/core/rss.c.
Or in lib/toeplitz.c just as like lib/siphash.c. I just chose the
easiest option to implement everything in include/linux/virtio_net.h.
>
>
>> 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 02a9f4dc594d..3b25ca75710b 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);
>> + }
>> +}
>
> Have you verified that this algorithm matches a known toeplitz
> implementation. And computes the expected values for the test
> inputs in
>
> https://learn.microsoft.com/en-us/windows-hardware/drivers/network/verifying-the-rss-hash-calculation
Yes.
>
> We have a toeplitz implementation in
> tools/testing/selftests/net/toeplitz.c that can also be used as
> reference.
> >> +
>> +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 + 4;
>
> Avoid magic constants. Please use sizeof or something else to signal
> what this 4 derives from.
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