From: Martin KaFai Lau Date: Wed, 7 Dec 2016 23:53:11 +0000 (-0800) Subject: bpf: xdp: Allow head adjustment in XDP prog X-Git-Tag: MMI-PSA29.97-13-9~6662^2~31^2~3 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=17bedab27231;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git bpf: xdp: Allow head adjustment in XDP prog This patch allows XDP prog to extend/remove the packet data at the head (like adding or removing header). It is done by adding a new XDP helper bpf_xdp_adjust_head(). It also renames bpf_helper_changes_skb_data() to bpf_helper_changes_pkt_data() to better reflect that XDP prog does not work on skb. This patch adds one "xdp_adjust_head" bit to bpf_prog for the XDP-capable driver to check if the XDP prog requires bpf_xdp_adjust_head() support. The driver can then decide to error out during XDP_SETUP_PROG. Signed-off-by: Martin KaFai Lau Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Acked-by: John Fastabend Signed-off-by: David S. Miller --- diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index 0fe98a567125..73a5cf18fd84 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -766,7 +766,7 @@ emit_clear: func = (u8 *) __bpf_call_base + imm; /* Save skb pointer if we need to re-cache skb data */ - if (bpf_helper_changes_skb_data(func)) + if (bpf_helper_changes_pkt_data(func)) PPC_BPF_STL(3, 1, bpf_jit_stack_local(ctx)); bpf_jit_emit_func_call(image, ctx, (u64)func); @@ -775,7 +775,7 @@ emit_clear: PPC_MR(b2p[BPF_REG_0], 3); /* refresh skb cache */ - if (bpf_helper_changes_skb_data(func)) { + if (bpf_helper_changes_pkt_data(func)) { /* reload skb pointer to r3 */ PPC_BPF_LL(3, 1, bpf_jit_stack_local(ctx)); bpf_jit_emit_skb_loads(image, ctx); diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index bee281f3163d..167b31b186c1 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -981,7 +981,7 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i EMIT2(0x0d00, REG_14, REG_W1); /* lgr %b0,%r2: load return value into %b0 */ EMIT4(0xb9040000, BPF_REG_0, REG_2); - if (bpf_helper_changes_skb_data((void *)func)) { + if (bpf_helper_changes_pkt_data((void *)func)) { jit->seen |= SEEN_SKB_CHANGE; /* lg %b1,ST_OFF_SKBP(%r15) */ EMIT6_DISP_LH(0xe3000000, 0x0004, BPF_REG_1, REG_0, diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index fe04a04dab8e..e76d1af60f7a 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -853,7 +853,7 @@ xadd: if (is_imm8(insn->off)) func = (u8 *) __bpf_call_base + imm32; jmp_offset = func - (image + addrs[i]); if (seen_ld_abs) { - reload_skb_data = bpf_helper_changes_skb_data(func); + reload_skb_data = bpf_helper_changes_pkt_data(func); if (reload_skb_data) { EMIT1(0x57); /* push %rdi */ jmp_offset += 22; /* pop, mov, sub, mov */ diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c index 49a81f1fc1d6..f441eda63bec 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c @@ -2686,6 +2686,11 @@ static int mlx4_xdp_set(struct net_device *dev, struct bpf_prog *prog) int err; int i; + if (prog && prog->xdp_adjust_head) { + en_err(priv, "Does not support bpf_xdp_adjust_head()\n"); + return -EOPNOTSUPP; + } + xdp_ring_num = prog ? priv->rx_ring_num : 0; /* No need to reconfigure buffers when simply swapping the diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index 07020276fe73..cbfa38fc72c0 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -3183,6 +3183,11 @@ static int mlx5e_xdp_set(struct net_device *netdev, struct bpf_prog *prog) bool reset, was_opened; int i; + if (prog && prog->xdp_adjust_head) { + netdev_err(netdev, "Does not support bpf_xdp_adjust_head()\n"); + return -EOPNOTSUPP; + } + mutex_lock(&priv->state_lock); if ((netdev->features & NETIF_F_LRO) && prog) { diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c index 00d9a03be31d..e8d448109e03 100644 --- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c +++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c @@ -2946,6 +2946,10 @@ static int nfp_net_xdp_setup(struct nfp_net *nn, struct bpf_prog *prog) }; int err; + if (prog && prog->xdp_adjust_head) { + nn_err(nn, "Does not support bpf_xdp_adjust_head()\n"); + return -EOPNOTSUPP; + } if (!prog && !nn->xdp_prog) return 0; if (prog && nn->xdp_prog) { diff --git a/drivers/net/ethernet/qlogic/qede/qede_main.c b/drivers/net/ethernet/qlogic/qede/qede_main.c index cf1dd1436d93..aecdd1c5c0ea 100644 --- a/drivers/net/ethernet/qlogic/qede/qede_main.c +++ b/drivers/net/ethernet/qlogic/qede/qede_main.c @@ -2507,6 +2507,11 @@ static int qede_xdp_set(struct qede_dev *edev, struct bpf_prog *prog) { struct qede_reload_args args; + if (prog && prog->xdp_adjust_head) { + DP_ERR(edev, "Does not support bpf_xdp_adjust_head()\n"); + return -EOPNOTSUPP; + } + /* If we're called, there was already a bpf reference increment */ args.func = &qede_xdp_reload_func; args.u.new_prog = prog; diff --git a/include/linux/filter.h b/include/linux/filter.h index f078d2b1cff6..6a1658308612 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -406,7 +406,8 @@ struct bpf_prog { u16 jited:1, /* Is our filter JIT'ed? */ gpl_compatible:1, /* Is filter GPL compatible? */ cb_access:1, /* Is control block accessed? */ - dst_needed:1; /* Do we need dst entry? */ + dst_needed:1, /* Do we need dst entry? */ + xdp_adjust_head:1; /* Adjusting pkt head? */ kmemcheck_bitfield_end(meta); enum bpf_prog_type type; /* Type of BPF program */ u32 len; /* Number of filter blocks */ @@ -440,6 +441,7 @@ struct bpf_skb_data_end { struct xdp_buff { void *data; void *data_end; + void *data_hard_start; }; /* compute the linear packet data range [data, data_end) which @@ -595,7 +597,7 @@ void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp); u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog); -bool bpf_helper_changes_skb_data(void *func); +bool bpf_helper_changes_pkt_data(void *func); struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, const struct bpf_insn *patch, u32 len); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 6123d9b8e828..0eb0e87dbe9f 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -424,6 +424,12 @@ union bpf_attr { * @len: length of header to be pushed in front * @flags: Flags (unused for now) * Return: 0 on success or negative error + * + * int bpf_xdp_adjust_head(xdp_md, delta) + * Adjust the xdp_md.data by delta + * @xdp_md: pointer to xdp_md + * @delta: An positive/negative integer to be added to xdp_md.data + * Return: 0 on success or negative on error */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -469,7 +475,8 @@ union bpf_attr { FN(csum_update), \ FN(set_hash_invalid), \ FN(get_numa_node_id), \ - FN(skb_change_head), + FN(skb_change_head), \ + FN(xdp_adjust_head), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call @@ -576,6 +583,8 @@ struct bpf_sock { __u32 protocol; }; +#define XDP_PACKET_HEADROOM 256 + /* User return codes for XDP prog type. * A valid XDP program must return one of these defined values. All other * return codes are reserved for future use. Unknown return codes will result diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index bdcc9f4ba767..83e0d153b0b4 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1143,7 +1143,7 @@ struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) return prog; } -bool __weak bpf_helper_changes_skb_data(void *func) +bool __weak bpf_helper_changes_pkt_data(void *func) { return false; } diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 88f609f1c0c3..4819ec9d95f6 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -579,6 +579,8 @@ static void fixup_bpf_calls(struct bpf_prog *prog) prog->dst_needed = 1; if (insn->imm == BPF_FUNC_get_prandom_u32) bpf_user_rnd_init_once(); + if (insn->imm == BPF_FUNC_xdp_adjust_head) + prog->xdp_adjust_head = 1; if (insn->imm == BPF_FUNC_tail_call) { /* mark bpf_tail_call as different opcode * to avoid conditional branch in diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5b14f85f45c6..d28f9a3380a9 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1216,7 +1216,7 @@ static int check_call(struct bpf_verifier_env *env, int func_id) return -EINVAL; } - changes_data = bpf_helper_changes_skb_data(fn->func); + changes_data = bpf_helper_changes_pkt_data(fn->func); memset(&meta, 0, sizeof(meta)); meta.pkt_access = fn->pkt_access; diff --git a/net/core/filter.c b/net/core/filter.c index b751202e12f8..b1461708a977 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2234,7 +2234,28 @@ static const struct bpf_func_proto bpf_skb_change_head_proto = { .arg3_type = ARG_ANYTHING, }; -bool bpf_helper_changes_skb_data(void *func) +BPF_CALL_2(bpf_xdp_adjust_head, struct xdp_buff *, xdp, int, offset) +{ + void *data = xdp->data + offset; + + if (unlikely(data < xdp->data_hard_start || + data > xdp->data_end - ETH_HLEN)) + return -EINVAL; + + xdp->data = data; + + return 0; +} + +static const struct bpf_func_proto bpf_xdp_adjust_head_proto = { + .func = bpf_xdp_adjust_head, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_ANYTHING, +}; + +bool bpf_helper_changes_pkt_data(void *func) { if (func == bpf_skb_vlan_push || func == bpf_skb_vlan_pop || @@ -2244,7 +2265,8 @@ bool bpf_helper_changes_skb_data(void *func) func == bpf_skb_change_tail || func == bpf_skb_pull_data || func == bpf_l3_csum_replace || - func == bpf_l4_csum_replace) + func == bpf_l4_csum_replace || + func == bpf_xdp_adjust_head) return true; return false; @@ -2670,6 +2692,8 @@ xdp_func_proto(enum bpf_func_id func_id) return &bpf_xdp_event_output_proto; case BPF_FUNC_get_smp_processor_id: return &bpf_get_smp_processor_id_proto; + case BPF_FUNC_xdp_adjust_head: + return &bpf_xdp_adjust_head_proto; default: return sk_filter_func_proto(func_id); }