From 9c395c1b99bd23f74bc628fa000480c49593d17f Mon Sep 17 00:00:00 2001 From: Dave Marchevsky Date: Mon, 13 Feb 2023 16:40:10 -0800 Subject: bpf: Add basic bpf_rb_{root,node} support This patch adds special BPF_RB_{ROOT,NODE} btf_field_types similar to BPF_LIST_{HEAD,NODE}, adds the necessary plumbing to detect the new types, and adds bpf_rb_root_free function for freeing bpf_rb_root in map_values. structs bpf_rb_root and bpf_rb_node are opaque types meant to obscure structs rb_root_cached rb_node, respectively. btf_struct_access will prevent BPF programs from touching these special fields automatically now that they're recognized. btf_check_and_fixup_fields now groups list_head and rb_root together as "graph root" fields and {list,rb}_node as "graph node", and does same ownership cycle checking as before. Note that this function does _not_ prevent ownership type mixups (e.g. rb_root owning list_node) - that's handled by btf_parse_graph_root. After this patch, a bpf program can have a struct bpf_rb_root in a map_value, but not add anything to nor do anything useful with it. Signed-off-by: Dave Marchevsky Link: https://lore.kernel.org/r/20230214004017.2534011-2-davemarchevsky@fb.com Signed-off-by: Alexei Starovoitov --- include/uapi/linux/bpf.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 17afd2b35ee5..1503f61336b6 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -6917,6 +6917,17 @@ struct bpf_list_node { __u64 :64; } __attribute__((aligned(8))); +struct bpf_rb_root { + __u64 :64; + __u64 :64; +} __attribute__((aligned(8))); + +struct bpf_rb_node { + __u64 :64; + __u64 :64; + __u64 :64; +} __attribute__((aligned(8))); + struct bpf_sysctl { __u32 write; /* Sysctl is being read (= 0) or written (= 1). * Allows 1,2,4-byte read, but no write. -- cgit v1.2.3 From 31de4105f00d64570139bc5494a201b0bd57349f Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Fri, 17 Feb 2023 12:55:14 -0800 Subject: bpf: Add BPF_FIB_LOOKUP_SKIP_NEIGH for bpf_fib_lookup The bpf_fib_lookup() also looks up the neigh table. This was done before bpf_redirect_neigh() was added. In the use case that does not manage the neigh table and requires bpf_fib_lookup() to lookup a fib to decide if it needs to redirect or not, the bpf prog can depend only on using bpf_redirect_neigh() to lookup the neigh. It also keeps the neigh entries fresh and connected. This patch adds a bpf_fib_lookup flag, SKIP_NEIGH, to avoid the double neigh lookup when the bpf prog always call bpf_redirect_neigh() to do the neigh lookup. The params->smac output is skipped together when SKIP_NEIGH is set because bpf_redirect_neigh() will figure out the smac also. Signed-off-by: Martin KaFai Lau Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20230217205515.3583372-1-martin.lau@linux.dev --- include/uapi/linux/bpf.h | 6 ++++++ net/core/filter.c | 39 ++++++++++++++++++++++++++------------- tools/include/uapi/linux/bpf.h | 6 ++++++ 3 files changed, 38 insertions(+), 13 deletions(-) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 1503f61336b6..62ce1f5d1b1d 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3134,6 +3134,11 @@ union bpf_attr { * **BPF_FIB_LOOKUP_OUTPUT** * Perform lookup from an egress perspective (default is * ingress). + * **BPF_FIB_LOOKUP_SKIP_NEIGH** + * Skip the neighbour table lookup. *params*->dmac + * and *params*->smac will not be set as output. A common + * use case is to call **bpf_redirect_neigh**\ () after + * doing **bpf_fib_lookup**\ (). * * *ctx* is either **struct xdp_md** for XDP programs or * **struct sk_buff** tc cls_act programs. @@ -6750,6 +6755,7 @@ struct bpf_raw_tracepoint_args { enum { BPF_FIB_LOOKUP_DIRECT = (1U << 0), BPF_FIB_LOOKUP_OUTPUT = (1U << 1), + BPF_FIB_LOOKUP_SKIP_NEIGH = (1U << 2), }; enum { diff --git a/net/core/filter.c b/net/core/filter.c index 8daaaf76ab15..1d6f165923bf 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5722,12 +5722,8 @@ static const struct bpf_func_proto bpf_skb_get_xfrm_state_proto = { #endif #if IS_ENABLED(CONFIG_INET) || IS_ENABLED(CONFIG_IPV6) -static int bpf_fib_set_fwd_params(struct bpf_fib_lookup *params, - const struct neighbour *neigh, - const struct net_device *dev, u32 mtu) +static int bpf_fib_set_fwd_params(struct bpf_fib_lookup *params, u32 mtu) { - memcpy(params->dmac, neigh->ha, ETH_ALEN); - memcpy(params->smac, dev->dev_addr, ETH_ALEN); params->h_vlan_TCI = 0; params->h_vlan_proto = 0; if (mtu) @@ -5838,21 +5834,29 @@ static int bpf_ipv4_fib_lookup(struct net *net, struct bpf_fib_lookup *params, if (likely(nhc->nhc_gw_family != AF_INET6)) { if (nhc->nhc_gw_family) params->ipv4_dst = nhc->nhc_gw.ipv4; - - neigh = __ipv4_neigh_lookup_noref(dev, - (__force u32)params->ipv4_dst); } else { struct in6_addr *dst = (struct in6_addr *)params->ipv6_dst; params->family = AF_INET6; *dst = nhc->nhc_gw.ipv6; - neigh = __ipv6_neigh_lookup_noref_stub(dev, dst); } + if (flags & BPF_FIB_LOOKUP_SKIP_NEIGH) + goto set_fwd_params; + + if (likely(nhc->nhc_gw_family != AF_INET6)) + neigh = __ipv4_neigh_lookup_noref(dev, + (__force u32)params->ipv4_dst); + else + neigh = __ipv6_neigh_lookup_noref_stub(dev, params->ipv6_dst); + if (!neigh || !(neigh->nud_state & NUD_VALID)) return BPF_FIB_LKUP_RET_NO_NEIGH; + memcpy(params->dmac, neigh->ha, ETH_ALEN); + memcpy(params->smac, dev->dev_addr, ETH_ALEN); - return bpf_fib_set_fwd_params(params, neigh, dev, mtu); +set_fwd_params: + return bpf_fib_set_fwd_params(params, mtu); } #endif @@ -5960,24 +5964,33 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params, params->rt_metric = res.f6i->fib6_metric; params->ifindex = dev->ifindex; + if (flags & BPF_FIB_LOOKUP_SKIP_NEIGH) + goto set_fwd_params; + /* xdp and cls_bpf programs are run in RCU-bh so rcu_read_lock_bh is * not needed here. */ neigh = __ipv6_neigh_lookup_noref_stub(dev, dst); if (!neigh || !(neigh->nud_state & NUD_VALID)) return BPF_FIB_LKUP_RET_NO_NEIGH; + memcpy(params->dmac, neigh->ha, ETH_ALEN); + memcpy(params->smac, dev->dev_addr, ETH_ALEN); - return bpf_fib_set_fwd_params(params, neigh, dev, mtu); +set_fwd_params: + return bpf_fib_set_fwd_params(params, mtu); } #endif +#define BPF_FIB_LOOKUP_MASK (BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_OUTPUT | \ + BPF_FIB_LOOKUP_SKIP_NEIGH) + BPF_CALL_4(bpf_xdp_fib_lookup, struct xdp_buff *, ctx, struct bpf_fib_lookup *, params, int, plen, u32, flags) { if (plen < sizeof(*params)) return -EINVAL; - if (flags & ~(BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_OUTPUT)) + if (flags & ~BPF_FIB_LOOKUP_MASK) return -EINVAL; switch (params->family) { @@ -6015,7 +6028,7 @@ BPF_CALL_4(bpf_skb_fib_lookup, struct sk_buff *, skb, if (plen < sizeof(*params)) return -EINVAL; - if (flags & ~(BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_OUTPUT)) + if (flags & ~BPF_FIB_LOOKUP_MASK) return -EINVAL; if (params->tot_len) diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 1503f61336b6..62ce1f5d1b1d 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3134,6 +3134,11 @@ union bpf_attr { * **BPF_FIB_LOOKUP_OUTPUT** * Perform lookup from an egress perspective (default is * ingress). + * **BPF_FIB_LOOKUP_SKIP_NEIGH** + * Skip the neighbour table lookup. *params*->dmac + * and *params*->smac will not be set as output. A common + * use case is to call **bpf_redirect_neigh**\ () after + * doing **bpf_fib_lookup**\ (). * * *ctx* is either **struct xdp_md** for XDP programs or * **struct sk_buff** tc cls_act programs. @@ -6750,6 +6755,7 @@ struct bpf_raw_tracepoint_args { enum { BPF_FIB_LOOKUP_DIRECT = (1U << 0), BPF_FIB_LOOKUP_OUTPUT = (1U << 1), + BPF_FIB_LOOKUP_SKIP_NEIGH = (1U << 2), }; enum { -- cgit v1.2.3