From fbee97feed9b3e4acdf9590e1f6b4a2eefecfffe Mon Sep 17 00:00:00 2001 From: David Ahern Date: Fri, 29 May 2020 16:07:13 -0600 Subject: bpf: Add support to attach bpf program to a devmap entry MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add BPF_XDP_DEVMAP attach type for use with programs associated with a DEVMAP entry. Allow DEVMAPs to associate a program with a device entry by adding a bpf_prog.fd to 'struct bpf_devmap_val'. Values read show the program id, so the fd and id are a union. bpf programs can get access to the struct via vmlinux.h. The program associated with the fd must have type XDP with expected attach type BPF_XDP_DEVMAP. When a program is associated with a device index, the program is run on an XDP_REDIRECT and before the buffer is added to the per-cpu queue. At this point rxq data is still valid; the next patch adds tx device information allowing the prorgam to see both ingress and egress device indices. XDP generic is skb based and XDP programs do not work with skb's. Block the use case by walking maps used by a program that is to be attached via xdpgeneric and fail if any of them are DEVMAP / DEVMAP_HASH with Block attach of BPF_XDP_DEVMAP programs to devices. Signed-off-by: David Ahern Signed-off-by: Alexei Starovoitov Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/bpf/20200529220716.75383-3-dsahern@kernel.org Signed-off-by: Alexei Starovoitov --- tools/include/uapi/linux/bpf.h | 1 + 1 file changed, 1 insertion(+) (limited to 'tools/include/uapi') diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 974ca6e948e3..65d7717bce2f 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -225,6 +225,7 @@ enum bpf_attach_type { BPF_CGROUP_INET6_GETPEERNAME, BPF_CGROUP_INET4_GETSOCKNAME, BPF_CGROUP_INET6_GETSOCKNAME, + BPF_XDP_DEVMAP, __MAX_BPF_ATTACH_TYPE }; -- cgit v1.2.3 From 64b59025c15b244c0954cf52b24fbabfcf5ed8f6 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Fri, 29 May 2020 16:07:14 -0600 Subject: xdp: Add xdp_txq_info to xdp_buff MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add xdp_txq_info as the Tx counterpart to xdp_rxq_info. At the moment only the device is added. Other fields (queue_index) can be added as use cases arise. >From a UAPI perspective, add egress_ifindex to xdp context for bpf programs to see the Tx device. Update the verifier to only allow accesses to egress_ifindex by XDP programs with BPF_XDP_DEVMAP expected attach type. Signed-off-by: David Ahern Signed-off-by: Alexei Starovoitov Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/bpf/20200529220716.75383-4-dsahern@kernel.org Signed-off-by: Alexei Starovoitov --- include/net/xdp.h | 5 +++++ include/uapi/linux/bpf.h | 2 ++ kernel/bpf/devmap.c | 3 +++ net/core/filter.c | 17 +++++++++++++++++ tools/include/uapi/linux/bpf.h | 2 ++ 5 files changed, 29 insertions(+) (limited to 'tools/include/uapi') diff --git a/include/net/xdp.h b/include/net/xdp.h index 90f11760bd12..d54022959491 100644 --- a/include/net/xdp.h +++ b/include/net/xdp.h @@ -61,12 +61,17 @@ struct xdp_rxq_info { struct xdp_mem_info mem; } ____cacheline_aligned; /* perf critical, avoid false-sharing */ +struct xdp_txq_info { + struct net_device *dev; +}; + struct xdp_buff { void *data; void *data_end; void *data_meta; void *data_hard_start; struct xdp_rxq_info *rxq; + struct xdp_txq_info *txq; u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/ }; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index f1e364d69007..f862a58fb567 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3707,6 +3707,8 @@ struct xdp_md { /* Below access go through struct xdp_rxq_info */ __u32 ingress_ifindex; /* rxq->dev->ifindex */ __u32 rx_queue_index; /* rxq->queue_index */ + + __u32 egress_ifindex; /* txq->dev->ifindex */ }; enum sk_action { diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 0089d56617ec..c04fb1c72f5e 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -476,8 +476,11 @@ static struct xdp_buff *dev_map_run_prog(struct net_device *dev, struct xdp_buff *xdp, struct bpf_prog *xdp_prog) { + struct xdp_txq_info txq = { .dev = dev }; u32 act; + xdp->txq = &txq; + act = bpf_prog_run_xdp(xdp_prog, xdp); switch (act) { case XDP_PASS: diff --git a/net/core/filter.c b/net/core/filter.c index 0008b029d644..85ff827aab73 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -7015,6 +7015,13 @@ static bool xdp_is_valid_access(int off, int size, const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { + if (prog->expected_attach_type != BPF_XDP_DEVMAP) { + switch (off) { + case offsetof(struct xdp_md, egress_ifindex): + return false; + } + } + if (type == BPF_WRITE) { if (bpf_prog_is_dev_bound(prog->aux)) { switch (off) { @@ -7985,6 +7992,16 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, offsetof(struct xdp_rxq_info, queue_index)); break; + case offsetof(struct xdp_md, egress_ifindex): + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct xdp_buff, txq), + si->dst_reg, si->src_reg, + offsetof(struct xdp_buff, txq)); + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct xdp_txq_info, dev), + si->dst_reg, si->dst_reg, + offsetof(struct xdp_txq_info, dev)); + *insn++ = BPF_LDX_MEM(BPF_W, si->dst_reg, si->dst_reg, + offsetof(struct net_device, ifindex)); + break; } return insn - insn_buf; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 65d7717bce2f..f74bc4a2385e 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3706,6 +3706,8 @@ struct xdp_md { /* Below access go through struct xdp_rxq_info */ __u32 ingress_ifindex; /* rxq->dev->ifindex */ __u32 rx_queue_index; /* rxq->queue_index */ + + __u32 egress_ifindex; /* txq->dev->ifindex */ }; enum sk_action { -- cgit v1.2.3