From 86af8b4191d20bb17e868d3167f4cf52ca9331d0 Mon Sep 17 00:00:00 2001 From: Brenden Blanco Date: Tue, 19 Jul 2016 12:16:51 -0700 Subject: Add sample for adding simple drop program to link Add a sample program that only drops packets at the BPF_PROG_TYPE_XDP_RX hook of a link. With the drop-only program, observed single core rate is ~20Mpps. Other tests were run, for instance without the dropcnt increment or without reading from the packet header, the packet rate was mostly unchanged. $ perf record -a samples/bpf/xdp1 $( Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index a98b780..0e4ab3a 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -21,6 +21,7 @@ hostprogs-y += spintest hostprogs-y += map_perf_test hostprogs-y += test_overhead hostprogs-y += test_cgrp2_array_pin +hostprogs-y += xdp1 test_verifier-objs := test_verifier.o libbpf.o test_maps-objs := test_maps.o libbpf.o @@ -42,6 +43,7 @@ spintest-objs := bpf_load.o libbpf.o spintest_user.o 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 # Tell kbuild to always build the programs always := $(hostprogs-y) @@ -64,6 +66,7 @@ always += test_overhead_tp_kern.o always += test_overhead_kprobe_kern.o always += parse_varlen.o parse_simple.o parse_ldabs.o always += test_cgrp2_tc_kern.o +always += xdp1_kern.o HOSTCFLAGS += -I$(objtree)/usr/include @@ -84,6 +87,7 @@ HOSTLOADLIBES_offwaketime += -lelf HOSTLOADLIBES_spintest += -lelf HOSTLOADLIBES_map_perf_test += -lelf -lrt HOSTLOADLIBES_test_overhead += -lelf -lrt +HOSTLOADLIBES_xdp1 += -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/bpf_load.c b/samples/bpf/bpf_load.c index 022af71..0cfda23 100644 --- a/samples/bpf/bpf_load.c +++ b/samples/bpf/bpf_load.c @@ -50,6 +50,7 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size) bool is_kprobe = strncmp(event, "kprobe/", 7) == 0; bool is_kretprobe = strncmp(event, "kretprobe/", 10) == 0; bool is_tracepoint = strncmp(event, "tracepoint/", 11) == 0; + bool is_xdp = strncmp(event, "xdp", 3) == 0; enum bpf_prog_type prog_type; char buf[256]; int fd, efd, err, id; @@ -66,6 +67,8 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size) prog_type = BPF_PROG_TYPE_KPROBE; } else if (is_tracepoint) { prog_type = BPF_PROG_TYPE_TRACEPOINT; + } else if (is_xdp) { + prog_type = BPF_PROG_TYPE_XDP; } else { printf("Unknown event '%s'\n", event); return -1; @@ -79,6 +82,9 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size) prog_fd[prog_cnt++] = fd; + if (is_xdp) + return 0; + if (is_socket) { event += 6; if (*event != '/') @@ -319,6 +325,7 @@ int load_bpf_file(char *path) if (memcmp(shname_prog, "kprobe/", 7) == 0 || memcmp(shname_prog, "kretprobe/", 10) == 0 || memcmp(shname_prog, "tracepoint/", 11) == 0 || + memcmp(shname_prog, "xdp", 3) == 0 || memcmp(shname_prog, "socket", 6) == 0) load_and_attach(shname_prog, insns, data_prog->d_size); } @@ -336,6 +343,7 @@ int load_bpf_file(char *path) if (memcmp(shname, "kprobe/", 7) == 0 || memcmp(shname, "kretprobe/", 10) == 0 || memcmp(shname, "tracepoint/", 11) == 0 || + memcmp(shname, "xdp", 3) == 0 || memcmp(shname, "socket", 6) == 0) load_and_attach(shname, data->d_buf, data->d_size); } diff --git a/samples/bpf/xdp1_kern.c b/samples/bpf/xdp1_kern.c new file mode 100644 index 0000000..e7dd8ac --- /dev/null +++ b/samples/bpf/xdp1_kern.c @@ -0,0 +1,93 @@ +/* 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 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; + + return rc; +} + +char _license[] SEC("license") = "GPL"; diff --git a/samples/bpf/xdp1_user.c b/samples/bpf/xdp1_user.c new file mode 100644 index 0000000..a5e109e --- /dev/null +++ b/samples/bpf/xdp1_user.c @@ -0,0 +1,181 @@ +/* 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. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "bpf_load.h" +#include "libbpf.h" + +static int set_link_xdp_fd(int ifindex, int fd) +{ + struct sockaddr_nl sa; + int sock, seq = 0, len, ret = -1; + char buf[4096]; + struct nlattr *nla, *nla_xdp; + struct { + struct nlmsghdr nh; + struct ifinfomsg ifinfo; + char attrbuf[64]; + } req; + struct nlmsghdr *nh; + struct nlmsgerr *err; + + memset(&sa, 0, sizeof(sa)); + sa.nl_family = AF_NETLINK; + + sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); + if (sock < 0) { + printf("open netlink socket: %s\n", strerror(errno)); + return -1; + } + + if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) { + printf("bind to netlink: %s\n", strerror(errno)); + goto cleanup; + } + + memset(&req, 0, sizeof(req)); + req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)); + req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; + req.nh.nlmsg_type = RTM_SETLINK; + req.nh.nlmsg_pid = 0; + req.nh.nlmsg_seq = ++seq; + req.ifinfo.ifi_family = AF_UNSPEC; + req.ifinfo.ifi_index = ifindex; + nla = (struct nlattr *)(((char *)&req) + + NLMSG_ALIGN(req.nh.nlmsg_len)); + nla->nla_type = NLA_F_NESTED | 43/*IFLA_XDP*/; + + nla_xdp = (struct nlattr *)((char *)nla + NLA_HDRLEN); + nla_xdp->nla_type = 1/*IFLA_XDP_FD*/; + nla_xdp->nla_len = NLA_HDRLEN + sizeof(int); + memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd)); + nla->nla_len = NLA_HDRLEN + nla_xdp->nla_len; + + req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len); + + if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) { + printf("send to netlink: %s\n", strerror(errno)); + goto cleanup; + } + + len = recv(sock, buf, sizeof(buf), 0); + if (len < 0) { + printf("recv from netlink: %s\n", strerror(errno)); + goto cleanup; + } + + for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len); + nh = NLMSG_NEXT(nh, len)) { + if (nh->nlmsg_pid != getpid()) { + printf("Wrong pid %d, expected %d\n", + nh->nlmsg_pid, getpid()); + goto cleanup; + } + if (nh->nlmsg_seq != seq) { + printf("Wrong seq %d, expected %d\n", + nh->nlmsg_seq, seq); + goto cleanup; + } + switch (nh->nlmsg_type) { + case NLMSG_ERROR: + err = (struct nlmsgerr *)NLMSG_DATA(nh); + if (!err->error) + continue; + printf("nlmsg error %s\n", strerror(-err->error)); + goto cleanup; + case NLMSG_DONE: + break; + } + } + + ret = 0; + +cleanup: + close(sock); + return ret; +} + +static int ifindex; + +static void int_exit(int sig) +{ + set_link_xdp_fd(ifindex, -1); + exit(0); +} + +/* simple per-protocol drop counter + */ +static void poll_stats(int interval) +{ + unsigned int nr_cpus = sysconf(_SC_NPROCESSORS_CONF); + const unsigned int nr_keys = 256; + __u64 values[nr_cpus], prev[nr_keys][nr_cpus]; + __u32 key; + int i; + + memset(prev, 0, sizeof(prev)); + + while (1) { + sleep(interval); + + for (key = 0; key < nr_keys; key++) { + __u64 sum = 0; + + assert(bpf_lookup_elem(map_fd[0], &key, values) == 0); + for (i = 0; i < nr_cpus; i++) + sum += (values[i] - prev[key][i]); + if (sum) + printf("proto %u: %10llu pkt/s\n", + key, sum / interval); + memcpy(prev[key], values, sizeof(values)); + } + } +} + +int main(int ac, char **argv) +{ + char filename[256]; + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + + if (ac != 2) { + printf("usage: %s IFINDEX\n", argv[0]); + return 1; + } + + ifindex = strtoul(argv[1], NULL, 0); + + if (load_bpf_file(filename)) { + printf("%s", bpf_log_buf); + return 1; + } + + if (!prog_fd[0]) { + printf("load_bpf_file: %s\n", strerror(errno)); + return 1; + } + + signal(SIGINT, int_exit); + + if (set_link_xdp_fd(ifindex, prog_fd[0]) < 0) { + printf("link set xdp fd failed\n"); + return 1; + } + + poll_stats(2); + + return 0; +} -- cgit v0.10.2