Return-path: Received: from s3.sipsolutions.net ([5.9.151.49]:35286 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752697AbdDLLHh (ORCPT ); Wed, 12 Apr 2017 07:07:37 -0400 From: Johannes Berg To: linux-wireless@vger.kernel.org, netdev@vger.kernel.org Cc: Johannes Berg Subject: [RFC 1/3] bpf/wireless: add wifimon program type Date: Wed, 12 Apr 2017 13:07:24 +0200 Message-Id: <20170412110726.9689-1-johannes@sipsolutions.net> (sfid-20170412_130910_059795_2268F0CA) Sender: linux-wireless-owner@vger.kernel.org List-ID: From: Johannes Berg Add a new program type for wifi monitor interfaces. This program type can * access __sk_buff, but only skb->len * call bpf_skb_load_bytes() The program type is only enabled when something selects the new Kconfig symbol WANT_BPF_WIFIMON, which will be done by mac80211 in a follow-up patch. Signed-off-by: Johannes Berg --- include/linux/bpf_types.h | 3 +++ include/uapi/linux/bpf.h | 1 + net/core/filter.c | 41 +++++++++++++++++++++++++++++++++++++++++ net/wireless/Kconfig | 8 ++++++++ 4 files changed, 53 insertions(+) diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index 03bf223f18be..fcaba84128dd 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -16,6 +16,9 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_KPROBE, kprobe_prog_ops) BPF_PROG_TYPE(BPF_PROG_TYPE_TRACEPOINT, tracepoint_prog_ops) BPF_PROG_TYPE(BPF_PROG_TYPE_PERF_EVENT, perf_event_prog_ops) #endif +#ifdef CONFIG_BPF_WIFIMON +BPF_PROG_TYPE(BPF_PROG_TYPE_WIFIMON, wifimon_prog_ops) +#endif BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_ARRAY, percpu_array_map_ops) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 1e062bb54eec..b0dfe8a79b3f 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -115,6 +115,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_LWT_IN, BPF_PROG_TYPE_LWT_OUT, BPF_PROG_TYPE_LWT_XMIT, + BPF_PROG_TYPE_WIFIMON, }; enum bpf_attach_type { diff --git a/net/core/filter.c b/net/core/filter.c index ce2a19da8aa4..c20624c81f6b 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3415,3 +3415,44 @@ int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf, release_sock(sk); return ret; } + +#ifdef CONFIG_BPF_WIFIMON +static const struct bpf_func_proto * +wifimon_func_proto(enum bpf_func_id func_id) +{ + switch (func_id) { + case BPF_FUNC_skb_load_bytes: + return &bpf_skb_load_bytes_proto; + default: + return bpf_base_func_proto(func_id); + } +} + +static bool wifimon_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 __sk_buff, len): + break; + default: + return false; + } + /* The verifier guarantees that size > 0. */ + if (off % size != 0) + return false; + if (size != sizeof(__u32)) + return false; + + return true; +} + +const struct bpf_verifier_ops wifimon_prog_ops = { + .get_func_proto = wifimon_func_proto, + .is_valid_access = wifimon_is_valid_access, + .convert_ctx_access = bpf_convert_ctx_access, +}; +#endif diff --git a/net/wireless/Kconfig b/net/wireless/Kconfig index 6c606120abfe..50ffebafce46 100644 --- a/net/wireless/Kconfig +++ b/net/wireless/Kconfig @@ -214,3 +214,11 @@ config LIB80211_DEBUG from lib80211. If unsure, say N. + +config WANT_BPF_WIFIMON + bool + +config BPF_WIFIMON + bool + default y + depends on WANT_BPF_WIFIMON && BPF_SYSCALL -- 2.11.0