| Message ID | 168010734324.3039990.16454026957159811204.stgit@firesoul (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | XDP-hints: API change for RX-hash kfunc bpf_xdp_metadata_rx_hash | expand |
On 29/03/2023 18.29, Jesper Dangaard Brouer wrote: > The RSS hash type specifies what portion of packet data NIC hardware used > when calculating RSS hash value. The RSS types are focused on Internet > traffic protocols at OSI layers L3 and L4. L2 (e.g. ARP) often get hash > value zero and no RSS type. For L3 focused on IPv4 vs. IPv6, and L4 > primarily TCP vs UDP, but some hardware supports SCTP. > > Hardware RSS types are differently encoded for each hardware NIC. Most > hardware represent RSS hash type as a number. Determining L3 vs L4 often > requires a mapping table as there often isn't a pattern or sorting > according to ISO layer. > > The patch introduce a XDP RSS hash type (xdp_rss_hash_type) that can both > be seen as a number that is ordered according by ISO layer, and can be bit > masked to separate IPv4 and IPv6 types for L4 protocols. Room is available > for extending later while keeping these properties. This maps and unifies > difference to hardware specific hashes. > > This proposal change the kfunc API bpf_xdp_metadata_rx_hash() to return > this RSS hash type on success. > > Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> > --- > include/net/xdp.h | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > net/core/xdp.c | 4 ++- > 2 files changed, 79 insertions(+), 1 deletion(-) > > diff --git a/include/net/xdp.h b/include/net/xdp.h > index 5393b3ebe56e..1b2b17625c26 100644 > --- a/include/net/xdp.h > +++ b/include/net/xdp.h > @@ -8,6 +8,7 @@ > > #include <linux/skbuff.h> /* skb_shared_info */ > #include <uapi/linux/netdev.h> > +#include <linux/bitfield.h> > > /** > * DOC: XDP RX-queue information > @@ -396,6 +397,81 @@ XDP_METADATA_KFUNC_xxx > MAX_XDP_METADATA_KFUNC, > }; > > +/* For partitioning of xdp_rss_hash_type */ > +#define RSS_L3 GENMASK(2,0) /* 3-bits = values between 1-7 */ > +#define L4_BIT BIT(3) /* 1-bit - L4 indication */ > +#define RSS_L4_IPV4 GENMASK(6,4) /* 3-bits */ > +#define RSS_L4_IPV6 GENMASK(9,7) /* 3-bits */ > +#define RSS_L4 GENMASK(9,3) /* = 7-bits - covering L4 IPV4+IPV6 */ > +#define L4_IPV6_EX_BIT BIT(9) /* 1-bit - L4 IPv6 with Extension hdr */ > + /* 11-bits in total */ Please ignore above lines in review ... they should have been deleted, the new partitioning uses the enum/defines below. > + > +/* Lower 4-bits value of xdp_rss_hash_type */ > +enum xdp_rss_L4 { > + XDP_RSS_L4_MASK = GENMASK(3,0), /* 4-bits = values between 0-15 */ > + XDP_RSS_L4_NONE = 0, /* Not L4 based hash */ > + XDP_RSS_L4_ANY = 1, /* L4 based hash but protocol unknown */ > + XDP_RSS_L4_TCP = 2, > + XDP_RSS_L4_UDP = 3, > + XDP_RSS_L4_SCTP = 4, > + XDP_RSS_L4_IPSEC = 5, /* L4 based hash include IPSEC SPI */ > +/* > + RFC: We don't care about vasting space, then we could just store the > + protocol number (8-bits) directly. See /etc/protocols > + XDP_RSS_L4_TCP = 6, > + XDP_RSS_L4_UDP = 17, > + XDP_RSS_L4_SCTP = 132, > + XDP_RSS_L4_IPSEC_ESP = 50, // Issue: mlx5 didn't say ESP or AH > + XDP_RSS_L4_IPSEC_AH = 51, // both ESP+AH just include SPI in hash > + */ > +}; > + > +/* Values shifted for use in xdp_rss_hash_type */ > +enum xdp_rss_L3 { > + XDP_RSS_L3_MASK = GENMASK(5,4), /* 2-bits = values between 1-3 */ > + XDP_RSS_L3_IPV4 = FIELD_PREP_CONST(XDP_RSS_L3_MASK, 1), > + XDP_RSS_L3_IPV6 = FIELD_PREP_CONST(XDP_RSS_L3_MASK, 2), > +}; > + > +/* Bits shifted for use in xdp_rss_hash_type */ > +enum xdp_rss_bit { > + XDP_RSS_BIT_MASK = GENMASK(7,6), /* 2-bits */ > + /* IPv6 Extension Hdr */ > + XDP_RSS_BIT_EX = FIELD_PREP_CONST(XDP_RSS_BIT_MASK, BIT(0)), > + /* XDP_RSS_BIT_VLAN ??? = FIELD_PREP_CONST(XDP_RSS_BIT_MASK, BIT(1)), */ > +}; > + > +/* RSS hash type combinations used for driver HW mapping */ > +enum xdp_rss_hash_type { > + XDP_RSS_TYPE_NONE = 0, > + XDP_RSS_TYPE_L2 = XDP_RSS_TYPE_NONE, > + > + XDP_RSS_TYPE_L3_MASK = XDP_RSS_L3_MASK, > + XDP_RSS_TYPE_L3_IPV4 = XDP_RSS_L3_IPV4, > + XDP_RSS_TYPE_L3_IPV6 = XDP_RSS_L3_IPV6, > + XDP_RSS_TYPE_L3_IPV6_EX = XDP_RSS_L3_IPV6 | XDP_RSS_BIT_EX, > + > + XDP_RSS_TYPE_L4_MASK = XDP_RSS_L4_MASK, > + XDP_RSS_TYPE_L4_ANY = XDP_RSS_L4_ANY, > + XDP_RSS_TYPE_L4_IPV4_TCP = XDP_RSS_L3_IPV4 | XDP_RSS_L4_TCP, > + XDP_RSS_TYPE_L4_IPV4_UDP = XDP_RSS_L3_IPV4 | XDP_RSS_L4_UDP, > + XDP_RSS_TYPE_L4_IPV4_SCTP = XDP_RSS_L3_IPV4 | XDP_RSS_L4_SCTP, > + > + XDP_RSS_TYPE_L4_IPV6_TCP = XDP_RSS_L3_IPV6 | XDP_RSS_L4_TCP, > + XDP_RSS_TYPE_L4_IPV6_UDP = XDP_RSS_L3_IPV6 | XDP_RSS_L4_UDP, > + XDP_RSS_TYPE_L4_IPV6_SCTP = XDP_RSS_L3_IPV6 | XDP_RSS_L4_UDP, > + > + XDP_RSS_TYPE_L4_IPV6_TCP_EX = XDP_RSS_TYPE_L4_IPV6_TCP |XDP_RSS_BIT_EX, > + XDP_RSS_TYPE_L4_IPV6_UDP_EX = XDP_RSS_TYPE_L4_IPV6_UDP |XDP_RSS_BIT_EX, > + XDP_RSS_TYPE_L4_IPV6_SCTP_EX = XDP_RSS_TYPE_L4_IPV6_SCTP|XDP_RSS_BIT_EX, > +}; > +#undef RSS_L3 > +#undef L4_BIT > +#undef RSS_L4_IPV4 > +#undef RSS_L4_IPV6 > +#undef RSS_L4 > +#undef L4_IPV6_EX_BIT All the undef's are also unncecessary now. > + > #ifdef CONFIG_NET > u32 bpf_xdp_metadata_kfunc_id(int id); > bool bpf_dev_bound_kfunc_id(u32 btf_id); > diff --git a/net/core/xdp.c b/net/core/xdp.c > index 7133017bcd74..81d41df30695 100644 > --- a/net/core/xdp.c > +++ b/net/core/xdp.c > @@ -721,12 +721,14 @@ __bpf_kfunc int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx, u64 *tim > * @hash: Return value pointer. > * > * Return: > - * * Returns 0 on success or ``-errno`` on error. > + * * Returns (positive) RSS hash **type** on success or ``-errno`` on error. > + * * ``enum xdp_rss_hash_type`` : RSS hash type > * * ``-EOPNOTSUPP`` : means device driver doesn't implement kfunc > * * ``-ENODATA`` : means no RX-hash available for this frame > */ > __bpf_kfunc int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, u32 *hash) > { > + BTF_TYPE_EMIT(enum xdp_rss_hash_type); > return -EOPNOTSUPP; > } > > >
Jesper Dangaard Brouer <brouer@redhat.com> writes: > diff --git a/net/core/xdp.c b/net/core/xdp.c > index 7133017bcd74..81d41df30695 100644 > --- a/net/core/xdp.c > +++ b/net/core/xdp.c > @@ -721,12 +721,14 @@ __bpf_kfunc int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx, u64 *tim > * @hash: Return value pointer. > * > * Return: > - * * Returns 0 on success or ``-errno`` on error. > + * * Returns (positive) RSS hash **type** on success or ``-errno`` on error. This change is going to break any BPF program that does: if (!bpf_xdp_metadata_rx_hash(ctx, &hash)) /* do something with hash */ so I think adding a second argument is better; that way, at least breakage will be explicit instead of being a hidden change in semantics (and the CO-RE style checking for kfuncs Alexei introduced should trigger correctly). But really, what we should do anyway is merge this during the -rc phase to minimise any breakage :) -Toke
diff --git a/include/net/xdp.h b/include/net/xdp.h index 5393b3ebe56e..1b2b17625c26 100644 --- a/include/net/xdp.h +++ b/include/net/xdp.h @@ -8,6 +8,7 @@ #include <linux/skbuff.h> /* skb_shared_info */ #include <uapi/linux/netdev.h> +#include <linux/bitfield.h> /** * DOC: XDP RX-queue information @@ -396,6 +397,81 @@ XDP_METADATA_KFUNC_xxx MAX_XDP_METADATA_KFUNC, }; +/* For partitioning of xdp_rss_hash_type */ +#define RSS_L3 GENMASK(2,0) /* 3-bits = values between 1-7 */ +#define L4_BIT BIT(3) /* 1-bit - L4 indication */ +#define RSS_L4_IPV4 GENMASK(6,4) /* 3-bits */ +#define RSS_L4_IPV6 GENMASK(9,7) /* 3-bits */ +#define RSS_L4 GENMASK(9,3) /* = 7-bits - covering L4 IPV4+IPV6 */ +#define L4_IPV6_EX_BIT BIT(9) /* 1-bit - L4 IPv6 with Extension hdr */ + /* 11-bits in total */ + +/* Lower 4-bits value of xdp_rss_hash_type */ +enum xdp_rss_L4 { + XDP_RSS_L4_MASK = GENMASK(3,0), /* 4-bits = values between 0-15 */ + XDP_RSS_L4_NONE = 0, /* Not L4 based hash */ + XDP_RSS_L4_ANY = 1, /* L4 based hash but protocol unknown */ + XDP_RSS_L4_TCP = 2, + XDP_RSS_L4_UDP = 3, + XDP_RSS_L4_SCTP = 4, + XDP_RSS_L4_IPSEC = 5, /* L4 based hash include IPSEC SPI */ +/* + RFC: We don't care about vasting space, then we could just store the + protocol number (8-bits) directly. See /etc/protocols + XDP_RSS_L4_TCP = 6, + XDP_RSS_L4_UDP = 17, + XDP_RSS_L4_SCTP = 132, + XDP_RSS_L4_IPSEC_ESP = 50, // Issue: mlx5 didn't say ESP or AH + XDP_RSS_L4_IPSEC_AH = 51, // both ESP+AH just include SPI in hash + */ +}; + +/* Values shifted for use in xdp_rss_hash_type */ +enum xdp_rss_L3 { + XDP_RSS_L3_MASK = GENMASK(5,4), /* 2-bits = values between 1-3 */ + XDP_RSS_L3_IPV4 = FIELD_PREP_CONST(XDP_RSS_L3_MASK, 1), + XDP_RSS_L3_IPV6 = FIELD_PREP_CONST(XDP_RSS_L3_MASK, 2), +}; + +/* Bits shifted for use in xdp_rss_hash_type */ +enum xdp_rss_bit { + XDP_RSS_BIT_MASK = GENMASK(7,6), /* 2-bits */ + /* IPv6 Extension Hdr */ + XDP_RSS_BIT_EX = FIELD_PREP_CONST(XDP_RSS_BIT_MASK, BIT(0)), + /* XDP_RSS_BIT_VLAN ??? = FIELD_PREP_CONST(XDP_RSS_BIT_MASK, BIT(1)), */ +}; + +/* RSS hash type combinations used for driver HW mapping */ +enum xdp_rss_hash_type { + XDP_RSS_TYPE_NONE = 0, + XDP_RSS_TYPE_L2 = XDP_RSS_TYPE_NONE, + + XDP_RSS_TYPE_L3_MASK = XDP_RSS_L3_MASK, + XDP_RSS_TYPE_L3_IPV4 = XDP_RSS_L3_IPV4, + XDP_RSS_TYPE_L3_IPV6 = XDP_RSS_L3_IPV6, + XDP_RSS_TYPE_L3_IPV6_EX = XDP_RSS_L3_IPV6 | XDP_RSS_BIT_EX, + + XDP_RSS_TYPE_L4_MASK = XDP_RSS_L4_MASK, + XDP_RSS_TYPE_L4_ANY = XDP_RSS_L4_ANY, + XDP_RSS_TYPE_L4_IPV4_TCP = XDP_RSS_L3_IPV4 | XDP_RSS_L4_TCP, + XDP_RSS_TYPE_L4_IPV4_UDP = XDP_RSS_L3_IPV4 | XDP_RSS_L4_UDP, + XDP_RSS_TYPE_L4_IPV4_SCTP = XDP_RSS_L3_IPV4 | XDP_RSS_L4_SCTP, + + XDP_RSS_TYPE_L4_IPV6_TCP = XDP_RSS_L3_IPV6 | XDP_RSS_L4_TCP, + XDP_RSS_TYPE_L4_IPV6_UDP = XDP_RSS_L3_IPV6 | XDP_RSS_L4_UDP, + XDP_RSS_TYPE_L4_IPV6_SCTP = XDP_RSS_L3_IPV6 | XDP_RSS_L4_UDP, + + XDP_RSS_TYPE_L4_IPV6_TCP_EX = XDP_RSS_TYPE_L4_IPV6_TCP |XDP_RSS_BIT_EX, + XDP_RSS_TYPE_L4_IPV6_UDP_EX = XDP_RSS_TYPE_L4_IPV6_UDP |XDP_RSS_BIT_EX, + XDP_RSS_TYPE_L4_IPV6_SCTP_EX = XDP_RSS_TYPE_L4_IPV6_SCTP|XDP_RSS_BIT_EX, +}; +#undef RSS_L3 +#undef L4_BIT +#undef RSS_L4_IPV4 +#undef RSS_L4_IPV6 +#undef RSS_L4 +#undef L4_IPV6_EX_BIT + #ifdef CONFIG_NET u32 bpf_xdp_metadata_kfunc_id(int id); bool bpf_dev_bound_kfunc_id(u32 btf_id); diff --git a/net/core/xdp.c b/net/core/xdp.c index 7133017bcd74..81d41df30695 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -721,12 +721,14 @@ __bpf_kfunc int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx, u64 *tim * @hash: Return value pointer. * * Return: - * * Returns 0 on success or ``-errno`` on error. + * * Returns (positive) RSS hash **type** on success or ``-errno`` on error. + * * ``enum xdp_rss_hash_type`` : RSS hash type * * ``-EOPNOTSUPP`` : means device driver doesn't implement kfunc * * ``-ENODATA`` : means no RX-hash available for this frame */ __bpf_kfunc int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, u32 *hash) { + BTF_TYPE_EMIT(enum xdp_rss_hash_type); return -EOPNOTSUPP; }
The RSS hash type specifies what portion of packet data NIC hardware used when calculating RSS hash value. The RSS types are focused on Internet traffic protocols at OSI layers L3 and L4. L2 (e.g. ARP) often get hash value zero and no RSS type. For L3 focused on IPv4 vs. IPv6, and L4 primarily TCP vs UDP, but some hardware supports SCTP. Hardware RSS types are differently encoded for each hardware NIC. Most hardware represent RSS hash type as a number. Determining L3 vs L4 often requires a mapping table as there often isn't a pattern or sorting according to ISO layer. The patch introduce a XDP RSS hash type (xdp_rss_hash_type) that can both be seen as a number that is ordered according by ISO layer, and can be bit masked to separate IPv4 and IPv6 types for L4 protocols. Room is available for extending later while keeping these properties. This maps and unifies difference to hardware specific hashes. This proposal change the kfunc API bpf_xdp_metadata_rx_hash() to return this RSS hash type on success. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> --- include/net/xdp.h | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++ net/core/xdp.c | 4 ++- 2 files changed, 79 insertions(+), 1 deletion(-)