[PATCH net-next 1/3] net: flow_dissector: extend bpf flow dissector support with vnet hdr
From: Tanner Love <hidden>
Date: 2021-05-27 21:12:27
Subsystem:
bonding driver, bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking drivers, networking [general], the rest · Maintainers:
Jay Vosburgh, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Tanner Love <redacted> Amend the bpf flow dissector program type to accept virtio_net_hdr members. Do this to enable bpf flow dissector programs to perform virtio-net header validation. The next patch in this series will add a flow dissection hook in virtio_net_hdr_to_skb and make use of this extended functionality. That commit message has more background on the use case. Signed-off-by: Tanner Love <redacted> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Petar Penkov <redacted> --- drivers/net/bonding/bond_main.c | 2 +- include/linux/skbuff.h | 26 ++++++++++++---- include/net/flow_dissector.h | 6 ++++ include/uapi/linux/bpf.h | 6 ++++ net/core/filter.c | 55 +++++++++++++++++++++++++++++++++ net/core/flow_dissector.c | 23 ++++++++++++-- tools/include/uapi/linux/bpf.h | 6 ++++ 7 files changed, 115 insertions(+), 9 deletions(-)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 7e469c203ca5..5d2d7d5c5704 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c@@ -3554,7 +3554,7 @@ static bool bond_flow_dissect(struct bonding *bond, struct sk_buff *skb, case BOND_XMIT_POLICY_ENCAP34: memset(fk, 0, sizeof(*fk)); return __skb_flow_dissect(NULL, skb, &flow_keys_bonding, - fk, NULL, 0, 0, 0, 0); + fk, NULL, 0, 0, 0, 0, NULL); default: break; }
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index dbf820a50a39..fef8f4b5db6e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h@@ -1312,18 +1312,20 @@ struct bpf_flow_dissector; bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx, __be16 proto, int nhoff, int hlen, unsigned int flags); +struct virtio_net_hdr; bool __skb_flow_dissect(const struct net *net, const struct sk_buff *skb, struct flow_dissector *flow_dissector, void *target_container, const void *data, - __be16 proto, int nhoff, int hlen, unsigned int flags); + __be16 proto, int nhoff, int hlen, unsigned int flags, + const struct virtio_net_hdr *vhdr); static inline bool skb_flow_dissect(const struct sk_buff *skb, struct flow_dissector *flow_dissector, void *target_container, unsigned int flags) { return __skb_flow_dissect(NULL, skb, flow_dissector, - target_container, NULL, 0, 0, 0, flags); + target_container, NULL, 0, 0, 0, flags, NULL); } static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb,
@@ -1332,7 +1334,20 @@ static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb, { memset(flow, 0, sizeof(*flow)); return __skb_flow_dissect(NULL, skb, &flow_keys_dissector, - flow, NULL, 0, 0, 0, flags); + flow, NULL, 0, 0, 0, flags, NULL); +} + +static inline bool +__skb_flow_dissect_flow_keys_basic(const struct net *net, + const struct sk_buff *skb, + struct flow_keys_basic *flow, + const void *data, __be16 proto, + int nhoff, int hlen, unsigned int flags, + const struct virtio_net_hdr *vhdr) +{ + memset(flow, 0, sizeof(*flow)); + return __skb_flow_dissect(net, skb, &flow_keys_basic_dissector, flow, + data, proto, nhoff, hlen, flags, vhdr); } static inline bool
@@ -1342,9 +1357,8 @@ skb_flow_dissect_flow_keys_basic(const struct net *net, const void *data, __be16 proto, int nhoff, int hlen, unsigned int flags) { - memset(flow, 0, sizeof(*flow)); - return __skb_flow_dissect(net, skb, &flow_keys_basic_dissector, flow, - data, proto, nhoff, hlen, flags); + return __skb_flow_dissect_flow_keys_basic(net, skb, flow, data, proto, + nhoff, hlen, flags, NULL); } void skb_flow_dissect_meta(const struct sk_buff *skb,
diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index ffd386ea0dbb..0796ad745e69 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h@@ -370,6 +370,12 @@ struct bpf_flow_dissector { const struct sk_buff *skb; const void *data; const void *data_end; + __u8 vhdr_flags; + __u8 vhdr_gso_type; + __u16 vhdr_hdr_len; + __u16 vhdr_gso_size; + __u16 vhdr_csum_start; + __u16 vhdr_csum_offset; }; static inline void
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 418b9b813d65..de525defd462 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h@@ -5155,6 +5155,12 @@ struct __sk_buff { __u32 gso_segs; __bpf_md_ptr(struct bpf_sock *, sk); __u32 gso_size; + __u8 vhdr_flags; + __u8 vhdr_gso_type; + __u16 vhdr_hdr_len; + __u16 vhdr_gso_size; + __u16 vhdr_csum_start; + __u16 vhdr_csum_offset; }; struct bpf_tunnel_key {
diff --git a/net/core/filter.c b/net/core/filter.c
index 239de1306de9..af45e769ced6 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -8358,6 +8358,16 @@ static bool flow_dissector_is_valid_access(int off, int size, return false; info->reg_type = PTR_TO_FLOW_KEYS; return true; + case bpf_ctx_range(struct __sk_buff, len): + return size == size_default; + case bpf_ctx_range(struct __sk_buff, vhdr_flags): + case bpf_ctx_range(struct __sk_buff, vhdr_gso_type): + return size == sizeof(__u8); + case bpf_ctx_range(struct __sk_buff, vhdr_hdr_len): + case bpf_ctx_range(struct __sk_buff, vhdr_gso_size): + case bpf_ctx_range(struct __sk_buff, vhdr_csum_start): + case bpf_ctx_range(struct __sk_buff, vhdr_csum_offset): + return size == sizeof(__u16); default: return false; }
@@ -8390,6 +8400,51 @@ static u32 flow_dissector_convert_ctx_access(enum bpf_access_type type, si->dst_reg, si->src_reg, offsetof(struct bpf_flow_dissector, flow_keys)); break; + + case offsetof(struct __sk_buff, vhdr_flags): + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_flow_dissector, vhdr_flags), + si->dst_reg, si->src_reg, + offsetof(struct bpf_flow_dissector, vhdr_flags)); + break; + + case offsetof(struct __sk_buff, vhdr_gso_type): + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_flow_dissector, vhdr_gso_type), + si->dst_reg, si->src_reg, + offsetof(struct bpf_flow_dissector, vhdr_gso_type)); + break; + + case offsetof(struct __sk_buff, vhdr_hdr_len): + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_flow_dissector, vhdr_hdr_len), + si->dst_reg, si->src_reg, + offsetof(struct bpf_flow_dissector, vhdr_hdr_len)); + break; + + case offsetof(struct __sk_buff, vhdr_gso_size): + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_flow_dissector, vhdr_gso_size), + si->dst_reg, si->src_reg, + offsetof(struct bpf_flow_dissector, vhdr_gso_size)); + break; + + case offsetof(struct __sk_buff, vhdr_csum_start): + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_flow_dissector, vhdr_csum_start), + si->dst_reg, si->src_reg, + offsetof(struct bpf_flow_dissector, vhdr_csum_start)); + break; + + case offsetof(struct __sk_buff, vhdr_csum_offset): + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_flow_dissector, vhdr_csum_offset), + si->dst_reg, si->src_reg, + offsetof(struct bpf_flow_dissector, vhdr_csum_offset)); + break; + + case offsetof(struct __sk_buff, len): + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_flow_dissector, skb), + si->dst_reg, si->src_reg, + offsetof(struct bpf_flow_dissector, skb)); + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, len), + si->dst_reg, si->dst_reg, + offsetof(struct sk_buff, len)); + break; } return insn - insn_buf;
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 3ed7c98a98e1..59639ad8700d 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c@@ -28,6 +28,7 @@ #include <scsi/fc/fc_fcoe.h> #include <uapi/linux/batadv_packet.h> #include <linux/bpf.h> +#include <linux/virtio_net.h> #if IS_ENABLED(CONFIG_NF_CONNTRACK) #include <net/netfilter/nf_conntrack_core.h> #include <net/netfilter/nf_conntrack_labels.h>
@@ -915,7 +916,8 @@ bool __skb_flow_dissect(const struct net *net, const struct sk_buff *skb, struct flow_dissector *flow_dissector, void *target_container, const void *data, - __be16 proto, int nhoff, int hlen, unsigned int flags) + __be16 proto, int nhoff, int hlen, unsigned int flags, + const struct virtio_net_hdr *vhdr) { struct flow_dissector_key_control *key_control; struct flow_dissector_key_basic *key_basic;
@@ -1001,6 +1003,23 @@ bool __skb_flow_dissect(const struct net *net, __be16 n_proto = proto; struct bpf_prog *prog; + if (vhdr) { + ctx.vhdr_flags = vhdr->flags; + ctx.vhdr_gso_type = vhdr->gso_type; + ctx.vhdr_hdr_len = + __virtio16_to_cpu(virtio_legacy_is_little_endian(), + vhdr->hdr_len); + ctx.vhdr_gso_size = + __virtio16_to_cpu(virtio_legacy_is_little_endian(), + vhdr->gso_size); + ctx.vhdr_csum_start = + __virtio16_to_cpu(virtio_legacy_is_little_endian(), + vhdr->csum_start); + ctx.vhdr_csum_offset = + __virtio16_to_cpu(virtio_legacy_is_little_endian(), + vhdr->csum_offset); + } + if (skb) { ctx.skb = skb; /* we can't use 'proto' in the skb case
@@ -1610,7 +1629,7 @@ u32 __skb_get_hash_symmetric(const struct sk_buff *skb) memset(&keys, 0, sizeof(keys)); __skb_flow_dissect(NULL, skb, &flow_keys_dissector_symmetric, &keys, NULL, 0, 0, 0, - FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL); + FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL, NULL); return __flow_hash_from_keys(&keys, &hashrnd); }
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 418b9b813d65..de525defd462 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h@@ -5155,6 +5155,12 @@ struct __sk_buff { __u32 gso_segs; __bpf_md_ptr(struct bpf_sock *, sk); __u32 gso_size; + __u8 vhdr_flags; + __u8 vhdr_gso_type; + __u16 vhdr_hdr_len; + __u16 vhdr_gso_size; + __u16 vhdr_csum_start; + __u16 vhdr_csum_offset; }; struct bpf_tunnel_key {
--
2.32.0.rc0.204.g9fa02ecfa5-goog