From 764cbccef8c9cb95e869ba2bb8371c42685c934a Mon Sep 17 00:00:00 2001 From: Brenden Blanco Date: Tue, 19 Jul 2016 12:16:57 -0700 Subject: [PATCH] bpf: add sample for xdp forwarding and rewrite Add a sample that rewrites and forwards packets out on the same interface. Observed single core forwarding performance of ~10Mpps. Since the mlx4 driver under test recycles every single packet page, the perf output shows almost exclusively just the ring management and bpf program work. Slowdowns are likely occurring due to cache misses. Signed-off-by: Brenden Blanco Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- samples/bpf/Makefile | 5 ++ samples/bpf/xdp2_kern.c | 114 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 119 insertions(+) create mode 100644 samples/bpf/xdp2_kern.c diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 0e4ab3a9dfa9..d2d2b35c67eb 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -22,6 +22,7 @@ hostprogs-y += map_perf_test hostprogs-y += test_overhead hostprogs-y += test_cgrp2_array_pin hostprogs-y += xdp1 +hostprogs-y += xdp2 test_verifier-objs := test_verifier.o libbpf.o test_maps-objs := test_maps.o libbpf.o @@ -44,6 +45,8 @@ map_perf_test-objs := bpf_load.o libbpf.o map_perf_test_user.o test_overhead-objs := bpf_load.o libbpf.o test_overhead_user.o test_cgrp2_array_pin-objs := libbpf.o test_cgrp2_array_pin.o xdp1-objs := bpf_load.o libbpf.o xdp1_user.o +# reuse xdp1 source intentionally +xdp2-objs := bpf_load.o libbpf.o xdp1_user.o # Tell kbuild to always build the programs always := $(hostprogs-y) @@ -67,6 +70,7 @@ always += test_overhead_kprobe_kern.o always += parse_varlen.o parse_simple.o parse_ldabs.o always += test_cgrp2_tc_kern.o always += xdp1_kern.o +always += xdp2_kern.o HOSTCFLAGS += -I$(objtree)/usr/include @@ -88,6 +92,7 @@ HOSTLOADLIBES_spintest += -lelf HOSTLOADLIBES_map_perf_test += -lelf -lrt HOSTLOADLIBES_test_overhead += -lelf -lrt HOSTLOADLIBES_xdp1 += -lelf +HOSTLOADLIBES_xdp2 += -lelf # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline: # make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang diff --git a/samples/bpf/xdp2_kern.c b/samples/bpf/xdp2_kern.c new file mode 100644 index 000000000000..38fe7e1d0db4 --- /dev/null +++ b/samples/bpf/xdp2_kern.c @@ -0,0 +1,114 @@ +/* Copyright (c) 2016 PLUMgrid + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#define KBUILD_MODNAME "foo" +#include +#include +#include +#include +#include +#include +#include +#include "bpf_helpers.h" + +struct bpf_map_def SEC("maps") dropcnt = { + .type = BPF_MAP_TYPE_PERCPU_ARRAY, + .key_size = sizeof(u32), + .value_size = sizeof(long), + .max_entries = 256, +}; + +static void swap_src_dst_mac(void *data) +{ + unsigned short *p = data; + unsigned short dst[3]; + + dst[0] = p[0]; + dst[1] = p[1]; + dst[2] = p[2]; + p[0] = p[3]; + p[1] = p[4]; + p[2] = p[5]; + p[3] = dst[0]; + p[4] = dst[1]; + p[5] = dst[2]; +} + +static int parse_ipv4(void *data, u64 nh_off, void *data_end) +{ + struct iphdr *iph = data + nh_off; + + if (iph + 1 > data_end) + return 0; + return iph->protocol; +} + +static int parse_ipv6(void *data, u64 nh_off, void *data_end) +{ + struct ipv6hdr *ip6h = data + nh_off; + + if (ip6h + 1 > data_end) + return 0; + return ip6h->nexthdr; +} + +SEC("xdp1") +int xdp_prog1(struct xdp_md *ctx) +{ + void *data_end = (void *)(long)ctx->data_end; + void *data = (void *)(long)ctx->data; + struct ethhdr *eth = data; + int rc = XDP_DROP; + long *value; + u16 h_proto; + u64 nh_off; + u32 index; + + nh_off = sizeof(*eth); + if (data + nh_off > data_end) + return rc; + + h_proto = eth->h_proto; + + if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) { + struct vlan_hdr *vhdr; + + vhdr = data + nh_off; + nh_off += sizeof(struct vlan_hdr); + if (data + nh_off > data_end) + return rc; + h_proto = vhdr->h_vlan_encapsulated_proto; + } + if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) { + struct vlan_hdr *vhdr; + + vhdr = data + nh_off; + nh_off += sizeof(struct vlan_hdr); + if (data + nh_off > data_end) + return rc; + h_proto = vhdr->h_vlan_encapsulated_proto; + } + + if (h_proto == htons(ETH_P_IP)) + index = parse_ipv4(data, nh_off, data_end); + else if (h_proto == htons(ETH_P_IPV6)) + index = parse_ipv6(data, nh_off, data_end); + else + index = 0; + + value = bpf_map_lookup_elem(&dropcnt, &index); + if (value) + *value += 1; + + if (index == 17) { + swap_src_dst_mac(data); + rc = XDP_TX; + } + + return rc; +} + +char _license[] SEC("license") = "GPL";