lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-Id: <1409106582-10095-27-git-send-email-ast@plumgrid.com> Date: Tue, 26 Aug 2014 19:29:40 -0700 From: Alexei Starovoitov <ast@...mgrid.com> To: "David S. Miller" <davem@...emloft.net> Cc: Ingo Molnar <mingo@...nel.org>, Linus Torvalds <torvalds@...ux-foundation.org>, Andy Lutomirski <luto@...capital.net>, Steven Rostedt <rostedt@...dmis.org>, Daniel Borkmann <dborkman@...hat.com>, Chema Gonzalez <chema@...gle.com>, Eric Dumazet <edumazet@...gle.com>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, Brendan Gregg <brendan.d.gregg@...il.com>, Namhyung Kim <namhyung@...nel.org>, "H. Peter Anvin" <hpa@...or.com>, Andrew Morton <akpm@...ux-foundation.org>, Kees Cook <keescook@...omium.org>, linux-api@...r.kernel.org, netdev@...r.kernel.org, linux-kernel@...r.kernel.org Subject: [PATCH RFC v7 net-next 26/28] samples: bpf: eBPF example in C ex1_kern.c - C program which will be compiled into eBPF to filter netif_receive_skb events on skb->dev->name == "lo" ex1_user.c - corresponding user space component that forever reads /sys/.../trace_pipe Usage: $ sudo ex1 should see: writing bpf-4 -> /sys/kernel/debug/tracing/events/net/netif_receive_skb/filter ping-25476 [001] ..s3 5639.718218: __netif_receive_skb_core: skb 4d51700 dev b9e6000 ping-25476 [001] ..s3 5639.718262: __netif_receive_skb_core: skb 4d51400 dev b9e6000 ping-25476 [002] ..s3 5640.716233: __netif_receive_skb_core: skb 5d06500 dev b9e6000 ping-25476 [002] ..s3 5640.716272: __netif_receive_skb_core: skb 5d06300 dev b9e6000 Ctrl-C at any time, kernel will auto cleanup Signed-off-by: Alexei Starovoitov <ast@...mgrid.com> --- samples/bpf/Makefile | 15 +++++++++++++-- samples/bpf/ex1_kern.c | 27 +++++++++++++++++++++++++++ samples/bpf/ex1_user.c | 24 ++++++++++++++++++++++++ 3 files changed, 64 insertions(+), 2 deletions(-) create mode 100644 samples/bpf/ex1_kern.c create mode 100644 samples/bpf/ex1_user.c diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 7264ba51d496..7ce9e6b0d3d0 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -2,12 +2,23 @@ obj- := dummy.o # List of programs to build -hostprogs-y := dropmon test_verifier +hostprogs-y := dropmon test_verifier ex1 dropmon-objs := dropmon.o libbpf.o test_verifier-objs := test_verifier.o libbpf.o +ex1-objs := bpf_load.o libbpf.o ex1_user.o # Tell kbuild to always build the programs -always := $(hostprogs-y) +always := $(hostprogs-y) ex1_kern.o HOSTCFLAGS += -I$(objtree)/usr/include + +HOSTCFLAGS_bpf_load.o += -I$(objtree)/usr/include -Wno-unused-variable +HOSTLOADLIBES_ex1 += -lelf + +LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc + +%.o: %.c + clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \ + -D__KERNEL__ -Wno-unused-value -Wno-pointer-sign \ + -O2 -emit-llvm -c $< -o -| $(LLC) -o $@ diff --git a/samples/bpf/ex1_kern.c b/samples/bpf/ex1_kern.c new file mode 100644 index 000000000000..05a06cccaadb --- /dev/null +++ b/samples/bpf/ex1_kern.c @@ -0,0 +1,27 @@ +#include <linux/skbuff.h> +#include <linux/netdevice.h> +#include <uapi/linux/bpf.h> +#include <trace/bpf_trace.h> +#include "bpf_helpers.h" + +SEC("events/net/netif_receive_skb") +int bpf_prog1(struct bpf_context *ctx) +{ + /* + * attaches to /sys/kernel/debug/tracing/events/net/netif_receive_skb + * prints events for loobpack device only + */ + char devname[] = "lo"; + struct net_device *dev; + struct sk_buff *skb = 0; + + skb = (struct sk_buff *) ctx->arg1; + dev = bpf_fetch_ptr(&skb->dev); + if (bpf_memcmp(dev->name, devname, 2) == 0) { + char fmt[] = "skb %x dev %x\n"; + bpf_printk(fmt, sizeof(fmt), skb, dev); + } + return 0; +} + +char license[] SEC("license") = "GPL"; diff --git a/samples/bpf/ex1_user.c b/samples/bpf/ex1_user.c new file mode 100644 index 000000000000..e85c1b483f57 --- /dev/null +++ b/samples/bpf/ex1_user.c @@ -0,0 +1,24 @@ +#include <stdio.h> +#include <linux/bpf.h> +#include "libbpf.h" +#include "bpf_load.h" + +int main(int ac, char **argv) +{ + FILE *f; + char filename[256]; + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + + if (load_bpf_file(filename)) { + printf("%s", bpf_log_buf); + return 1; + } + + f = popen("ping -c5 localhost", "r"); + (void) f; + + read_trace_pipe(); + + return 0; +} -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists