From patchwork Tue Jul 19 19:16:47 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Brenden Blanco X-Patchwork-Id: 650389 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3rv8tx6CNPz9sf9 for ; Wed, 20 Jul 2016 05:17:29 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=plumgrid-com.20150623.gappssmtp.com header.i=@plumgrid-com.20150623.gappssmtp.com header.b=avenG7ny; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751894AbcGSTR2 (ORCPT ); Tue, 19 Jul 2016 15:17:28 -0400 Received: from mail-pa0-f52.google.com ([209.85.220.52]:33778 "EHLO mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751716AbcGSTRZ (ORCPT ); Tue, 19 Jul 2016 15:17:25 -0400 Received: by mail-pa0-f52.google.com with SMTP id ks6so9793773pab.0 for ; Tue, 19 Jul 2016 12:17:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=plumgrid-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=1QokNTYvmNvJZSQ1xQothB+p9Lo5gGdzXUxFGxX7EV4=; b=avenG7nyramsbunhnwpLvm1AiphMGOXt7gYC3dpxcm8OFUzgAL/hndSnl5k4dtI3Ka 81ljwijkVeloA/TKPg68flilHL6fqbt+O/MNjPSd8hAft/w8AtMad09hE9oP0uyjW5JX 6ct1h2u9XAgbKctARzcU2o7Z/zLaTtz0OLfK5/bzxP7yAlWoUmJkR6c3O7i0B3eVNB3+ kVVKLyks7hi5nb81Ps5V7SlzF6VBJB/Of8X1V/Y/JBsbu1K/hnCjK6b+FcLrHObQku25 uRdAGWRCUD45MnWiCq5eb0bt+cx8o1e4LNxxlfjA+EsVXUhwY7lAoQ7mIUmN/HJjFYyR 34Bg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=1QokNTYvmNvJZSQ1xQothB+p9Lo5gGdzXUxFGxX7EV4=; b=iesi54y0QQEOzNRwRBFBdopsTxhm7emHEqKaB7RxyP6jmthGgWOmIpFKb6qZ6GDlRK 1rXCW/Gr8cc5d6n7xNQ1FzbFGngG6sT4LIK4FmonBqitnZwD3EDWG7oiw8lZw9shZLRR ynhiwBSf5LyRJxvW35ITwz1ZQnlGEhmEyHtCHSwhT4U6vRU3U+Uc8oTjMU5QpvjvwzAe xH9llnrS8GBCjYN4g7F3zrWrOtpInyvZdwuLDScUlmD7MeFfkzAtTOB7wT/G+W3rv6Xg Hs7XBbTGuZDLA7UmS6tdQLesxRr3EdxiG/ruNwxncM8h1o+1/a3WoM9hAMFb4wg4oIva S3zg== X-Gm-Message-State: ALyK8tLQ/RvObJpLMcS920xZegm1fguiBw2Exv5MzbkWdppHf1nGVAnc3tEJ8wur9kai+16s X-Received: by 10.66.127.10 with SMTP id nc10mr67583312pab.109.1468955844765; Tue, 19 Jul 2016 12:17:24 -0700 (PDT) Received: from iovisor-test1.plumgrid.com ([12.97.19.201]) by smtp.gmail.com with ESMTPSA id d5sm6644727pfc.4.2016.07.19.12.17.23 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 19 Jul 2016 12:17:23 -0700 (PDT) From: Brenden Blanco To: davem@davemloft.net, netdev@vger.kernel.org Cc: Brenden Blanco , Jamal Hadi Salim , Saeed Mahameed , Martin KaFai Lau , Jesper Dangaard Brouer , Ari Saha , Alexei Starovoitov , Or Gerlitz , john.fastabend@gmail.com, hannes@stressinduktion.org, Thomas Graf , Tom Herbert , Daniel Borkmann , Tariq Toukan Subject: [PATCH v10 02/12] bpf: add XDP prog type for early driver filter Date: Tue, 19 Jul 2016 12:16:47 -0700 Message-Id: <1468955817-10604-3-git-send-email-bblanco@plumgrid.com> X-Mailer: git-send-email 2.8.2 In-Reply-To: <1468955817-10604-1-git-send-email-bblanco@plumgrid.com> References: <1468955817-10604-1-git-send-email-bblanco@plumgrid.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Add a new bpf prog type that is intended to run in early stages of the packet rx path. Only minimal packet metadata will be available, hence a new context type, struct xdp_md, is exposed to userspace. So far only expose the packet start and end pointers, and only in read mode. An XDP program must return one of the well known enum values, all other return codes are reserved for future use. Unfortunately, this restriction is hard to enforce at verification time, so take the approach of warning at runtime when such programs are encountered. Out of bounds return codes should alias to XDP_ABORTED. Signed-off-by: Brenden Blanco Acked-by: Alexei Starovoitov --- include/linux/filter.h | 18 +++++++++++ include/uapi/linux/bpf.h | 20 ++++++++++++ kernel/bpf/verifier.c | 1 + net/core/filter.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 118 insertions(+) diff --git a/include/linux/filter.h b/include/linux/filter.h index 6fc31ef..15d816a 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -368,6 +368,11 @@ struct bpf_skb_data_end { void *data_end; }; +struct xdp_buff { + void *data; + void *data_end; +}; + /* compute the linear packet data range [data, data_end) which * will be accessed by cls_bpf and act_bpf programs */ @@ -429,6 +434,18 @@ static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog, return BPF_PROG_RUN(prog, skb); } +static inline u32 bpf_prog_run_xdp(const struct bpf_prog *prog, + struct xdp_buff *xdp) +{ + u32 ret; + + rcu_read_lock(); + ret = BPF_PROG_RUN(prog, (void *)xdp); + rcu_read_unlock(); + + return ret; +} + static inline unsigned int bpf_prog_size(unsigned int proglen) { return max(sizeof(struct bpf_prog), @@ -509,6 +526,7 @@ bool bpf_helper_changes_skb_data(void *func); struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, const struct bpf_insn *patch, u32 len); +void bpf_warn_invalid_xdp_action(u32 act); #ifdef CONFIG_BPF_JIT extern int bpf_jit_enable; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index c4d9224..a517865 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -94,6 +94,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_SCHED_CLS, BPF_PROG_TYPE_SCHED_ACT, BPF_PROG_TYPE_TRACEPOINT, + BPF_PROG_TYPE_XDP, }; #define BPF_PSEUDO_MAP_FD 1 @@ -439,4 +440,23 @@ struct bpf_tunnel_key { __u32 tunnel_label; }; +/* 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 + * in packet drop. + */ +enum xdp_action { + XDP_ABORTED = 0, + XDP_DROP, + XDP_PASS, +}; + +/* user accessible metadata for XDP packet hook + * new fields must be added to the end of this structure + */ +struct xdp_md { + __u32 data; + __u32 data_end; +}; + #endif /* _UAPI__LINUX_BPF_H__ */ diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index e206c21..a8d67d0 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -713,6 +713,7 @@ static int check_ptr_alignment(struct verifier_env *env, struct reg_state *reg, switch (env->prog->type) { case BPF_PROG_TYPE_SCHED_CLS: case BPF_PROG_TYPE_SCHED_ACT: + case BPF_PROG_TYPE_XDP: break; default: verbose("verifier is misconfigured\n"); diff --git a/net/core/filter.c b/net/core/filter.c index 22e3992..6c627bc 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2410,6 +2410,12 @@ tc_cls_act_func_proto(enum bpf_func_id func_id) } } +static const struct bpf_func_proto * +xdp_func_proto(enum bpf_func_id func_id) +{ + return sk_filter_func_proto(func_id); +} + static bool __is_valid_access(int off, int size, enum bpf_access_type type) { if (off < 0 || off >= sizeof(struct __sk_buff)) @@ -2477,6 +2483,44 @@ static bool tc_cls_act_is_valid_access(int off, int size, return __is_valid_access(off, size, type); } +static bool __is_valid_xdp_access(int off, int size, + enum bpf_access_type type) +{ + if (off < 0 || off >= sizeof(struct xdp_md)) + return false; + if (off % size != 0) + return false; + if (size != 4) + return false; + + return true; +} + +static bool xdp_is_valid_access(int off, int size, + enum bpf_access_type type, + enum bpf_reg_type *reg_type) +{ + if (type == BPF_WRITE) + return false; + + switch (off) { + case offsetof(struct xdp_md, data): + *reg_type = PTR_TO_PACKET; + break; + case offsetof(struct xdp_md, data_end): + *reg_type = PTR_TO_PACKET_END; + break; + } + + return __is_valid_xdp_access(off, size, type); +} + +void bpf_warn_invalid_xdp_action(u32 act) +{ + WARN_ONCE(1, "Illegal XDP return value %u, expect packet loss\n", act); +} +EXPORT_SYMBOL_GPL(bpf_warn_invalid_xdp_action); + static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg, int src_reg, int ctx_off, struct bpf_insn *insn_buf, @@ -2628,6 +2672,29 @@ static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg, return insn - insn_buf; } +static u32 xdp_convert_ctx_access(enum bpf_access_type type, int dst_reg, + int src_reg, int ctx_off, + struct bpf_insn *insn_buf, + struct bpf_prog *prog) +{ + struct bpf_insn *insn = insn_buf; + + switch (ctx_off) { + case offsetof(struct xdp_md, data): + *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct xdp_buff, data)), + dst_reg, src_reg, + offsetof(struct xdp_buff, data)); + break; + case offsetof(struct xdp_md, data_end): + *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct xdp_buff, data_end)), + dst_reg, src_reg, + offsetof(struct xdp_buff, data_end)); + break; + } + + return insn - insn_buf; +} + static const struct bpf_verifier_ops sk_filter_ops = { .get_func_proto = sk_filter_func_proto, .is_valid_access = sk_filter_is_valid_access, @@ -2640,6 +2707,12 @@ static const struct bpf_verifier_ops tc_cls_act_ops = { .convert_ctx_access = bpf_net_convert_ctx_access, }; +static const struct bpf_verifier_ops xdp_ops = { + .get_func_proto = xdp_func_proto, + .is_valid_access = xdp_is_valid_access, + .convert_ctx_access = xdp_convert_ctx_access, +}; + static struct bpf_prog_type_list sk_filter_type __read_mostly = { .ops = &sk_filter_ops, .type = BPF_PROG_TYPE_SOCKET_FILTER, @@ -2655,11 +2728,17 @@ static struct bpf_prog_type_list sched_act_type __read_mostly = { .type = BPF_PROG_TYPE_SCHED_ACT, }; +static struct bpf_prog_type_list xdp_type __read_mostly = { + .ops = &xdp_ops, + .type = BPF_PROG_TYPE_XDP, +}; + static int __init register_sk_filter_ops(void) { bpf_register_prog_type(&sk_filter_type); bpf_register_prog_type(&sched_cls_type); bpf_register_prog_type(&sched_act_type); + bpf_register_prog_type(&xdp_type); return 0; }