From patchwork Mon Dec 1 23:06:36 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexei Starovoitov X-Patchwork-Id: 416609 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 9B73414003E for ; Tue, 2 Dec 2014 10:09:28 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932842AbaLAXIn (ORCPT ); Mon, 1 Dec 2014 18:08:43 -0500 Received: from mail-pd0-f177.google.com ([209.85.192.177]:55460 "EHLO mail-pd0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932737AbaLAXGy (ORCPT ); Mon, 1 Dec 2014 18:06:54 -0500 Received: by mail-pd0-f177.google.com with SMTP id ft15so11735956pdb.22 for ; Mon, 01 Dec 2014 15:06:53 -0800 (PST) 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=a8DRo0OsXUeAqRlJ3FCvJRwZrSN8KnZtea6Rn80GKhc=; b=T+1cLDVd6W6JB/Vuh2igzqJeMk0QSHq4y8TKwMh9cYd1kbBa7LM8BQ03vKQnz5hTXt fF60GcmLwBZyTlb7a9OpYNCTOoB7+2qOtITplklc8UvxrLOKZpfZO9nj8oY+AuIxAEYZ rflzpUdIN/2fCQiILEN7TOTfvuoea4mC878hnTzEaUzpFhpl8f/KLK/Cqgns1dQsEqx2 4gumeJXzFneAyZMFWea/x2v09eIl0B9Tt+Upd6rOHv95hXjoBJWvZoM+58oxCYhu8uEy odGat6bMO55PWKDjE3/ST0O+YF1yS6gQgLA6YOeZTDeSnSacJNDdiNdprL/U0YgASj4X G7Tg== X-Gm-Message-State: ALoCoQnFTWPSb9NTRtsNCuf+8d8LFamenLYOY5kWkaxGtWgYhZJYse+PgL6JT12kPO2E8P58k2q7 X-Received: by 10.68.221.162 with SMTP id qf2mr206862pbc.148.1417475213386; Mon, 01 Dec 2014 15:06:53 -0800 (PST) Received: from localhost.localdomain ([12.229.56.226]) by mx.google.com with ESMTPSA id zn2sm18431679pbb.41.2014.12.01.15.06.52 for (version=TLSv1.1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 01 Dec 2014 15:06:52 -0800 (PST) From: Alexei Starovoitov To: "David S. Miller" Cc: Ingo Molnar , Andy Lutomirski , Daniel Borkmann , Hannes Frederic Sowa , Eric Dumazet , linux-api@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 net-next 3/6] samples: bpf: example of stateful socket filtering Date: Mon, 1 Dec 2014 15:06:36 -0800 Message-Id: <1417475199-15950-4-git-send-email-ast@plumgrid.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1417475199-15950-1-git-send-email-ast@plumgrid.com> References: <1417475199-15950-1-git-send-email-ast@plumgrid.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org this socket filter example does: - creates arraymap in kernel with key 4 bytes and value 8 bytes - loads eBPF program which assumes that packet is IPv4 and loads one byte of IP->proto from the packet and uses it as a key in a map r0 = skb->data[ETH_HLEN + offsetof(struct iphdr, protocol)]; *(u32*)(fp - 4) = r0; value = bpf_map_lookup_elem(map_fd, fp - 4); if (value) (*(u64*)value) += 1; - attaches this program to raw socket - every second user space reads map[IPPROTO_TCP], map[IPPROTO_UDP], map[IPPROTO_ICMP] to see how many packets of given protocol were seen on loopback interface Usage: $sudo samples/bpf/sock_example TCP 0 UDP 0 ICMP 0 packets TCP 187600 UDP 0 ICMP 4 packets TCP 376504 UDP 0 ICMP 8 packets TCP 563116 UDP 0 ICMP 12 packets TCP 753144 UDP 0 ICMP 16 packets Signed-off-by: Alexei Starovoitov --- V1->V2: fixed comments and replaced constants in: BPF_LD_ABS(BPF_B, 14 + 9 /* R0 = ip->proto */), with: BPF_LD_ABS(BPF_B, ETH_HLEN + offsetof(struct iphdr, protocol) /* R0 = ip->proto */), samples/bpf/Makefile | 2 + samples/bpf/libbpf.c | 28 ++++++++++++ samples/bpf/libbpf.h | 13 ++++++ samples/bpf/sock_example.c | 101 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 144 insertions(+) create mode 100644 samples/bpf/sock_example.c diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 0718d9ce4619..f46d3492d032 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -3,9 +3,11 @@ obj- := dummy.o # List of programs to build hostprogs-y := test_verifier test_maps +hostprogs-y += sock_example test_verifier-objs := test_verifier.o libbpf.o test_maps-objs := test_maps.o libbpf.o +sock_example-objs := sock_example.o libbpf.o # Tell kbuild to always build the programs always := $(hostprogs-y) diff --git a/samples/bpf/libbpf.c b/samples/bpf/libbpf.c index 17bb520eb57f..46d50b7ddf79 100644 --- a/samples/bpf/libbpf.c +++ b/samples/bpf/libbpf.c @@ -7,6 +7,10 @@ #include #include #include +#include +#include +#include +#include #include "libbpf.h" static __u64 ptr_to_u64(void *ptr) @@ -93,3 +97,27 @@ int bpf_prog_load(enum bpf_prog_type prog_type, return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr)); } + +int open_raw_sock(const char *name) +{ + struct sockaddr_ll sll; + int sock; + + sock = socket(PF_PACKET, SOCK_RAW | SOCK_NONBLOCK | SOCK_CLOEXEC, htons(ETH_P_ALL)); + if (sock < 0) { + printf("cannot create raw socket\n"); + return -1; + } + + memset(&sll, 0, sizeof(sll)); + sll.sll_family = AF_PACKET; + sll.sll_ifindex = if_nametoindex(name); + sll.sll_protocol = htons(ETH_P_ALL); + if (bind(sock, (struct sockaddr *)&sll, sizeof(sll)) < 0) { + printf("bind to %s: %s\n", name, strerror(errno)); + close(sock); + return -1; + } + + return sock; +} diff --git a/samples/bpf/libbpf.h b/samples/bpf/libbpf.h index f8678e5f48bf..cc62ad4d95de 100644 --- a/samples/bpf/libbpf.h +++ b/samples/bpf/libbpf.h @@ -99,6 +99,16 @@ extern char bpf_log_buf[LOG_BUF_SIZE]; BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD) +/* Direct packet access, R0 = *(uint *) (skb->data + imm32) */ + +#define BPF_LD_ABS(SIZE, IMM) \ + ((struct bpf_insn) { \ + .code = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS, \ + .dst_reg = 0, \ + .src_reg = 0, \ + .off = 0, \ + .imm = IMM }) + /* Memory load, dst_reg = *(uint *) (src_reg + off16) */ #define BPF_LDX_MEM(SIZE, DST, SRC, OFF) \ @@ -169,4 +179,7 @@ extern char bpf_log_buf[LOG_BUF_SIZE]; .off = 0, \ .imm = 0 }) +/* create RAW socket and bind to interface 'name' */ +int open_raw_sock(const char *name); + #endif diff --git a/samples/bpf/sock_example.c b/samples/bpf/sock_example.c new file mode 100644 index 000000000000..c8ad0404416f --- /dev/null +++ b/samples/bpf/sock_example.c @@ -0,0 +1,101 @@ +/* eBPF example program: + * - creates arraymap in kernel with key 4 bytes and value 8 bytes + * + * - loads eBPF program: + * r0 = skb->data[ETH_HLEN + offsetof(struct iphdr, protocol)]; + * *(u32*)(fp - 4) = r0; + * // assuming packet is IPv4, lookup ip->proto in a map + * value = bpf_map_lookup_elem(map_fd, fp - 4); + * if (value) + * (*(u64*)value) += 1; + * + * - attaches this program to eth0 raw socket + * + * - every second user space reads map[tcp], map[udp], map[icmp] to see + * how many packets of given protocol were seen on eth0 + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "libbpf.h" + +static int test_sock(void) +{ + int sock = -1, map_fd, prog_fd, i, key; + long long value = 0, tcp_cnt, udp_cnt, icmp_cnt; + + map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, sizeof(key), sizeof(value), + 256); + if (map_fd < 0) { + printf("failed to create map '%s'\n", strerror(errno)); + goto cleanup; + } + + struct bpf_insn prog[] = { + BPF_MOV64_REG(BPF_REG_6, BPF_REG_1), + BPF_LD_ABS(BPF_B, ETH_HLEN + offsetof(struct iphdr, protocol) /* R0 = ip->proto */), + BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */ + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */ + BPF_LD_MAP_FD(BPF_REG_1, map_fd), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + BPF_MOV64_IMM(BPF_REG_1, 1), /* r1 = 1 */ + BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */ + BPF_MOV64_IMM(BPF_REG_0, 0), /* r0 = 0 */ + BPF_EXIT_INSN(), + }; + + prog_fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, prog, sizeof(prog), + "GPL"); + if (prog_fd < 0) { + printf("failed to load prog '%s'\n", strerror(errno)); + goto cleanup; + } + + sock = open_raw_sock("lo"); + + if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &prog_fd, + sizeof(prog_fd)) < 0) { + printf("setsockopt %s\n", strerror(errno)); + goto cleanup; + } + + for (i = 0; i < 10; i++) { + key = IPPROTO_TCP; + assert(bpf_lookup_elem(map_fd, &key, &tcp_cnt) == 0); + + key = IPPROTO_UDP; + assert(bpf_lookup_elem(map_fd, &key, &udp_cnt) == 0); + + key = IPPROTO_ICMP; + assert(bpf_lookup_elem(map_fd, &key, &icmp_cnt) == 0); + + printf("TCP %lld UDP %lld ICMP %lld packets\n", + tcp_cnt, udp_cnt, icmp_cnt); + sleep(1); + } + +cleanup: + /* maps, programs, raw sockets will auto cleanup on process exit */ + return 0; +} + +int main(void) +{ + FILE *f; + + f = popen("ping -c5 localhost", "r"); + (void)f; + + return test_sock(); +}