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 --- samples/bpf/xdp1_user.c | 181 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 181 insertions(+) create mode 100644 samples/bpf/xdp1_user.c (limited to 'samples/bpf/xdp1_user.c') diff --git a/samples/bpf/xdp1_user.c b/samples/bpf/xdp1_user.c new file mode 100644 index 000000000000..a5e109e398a1 --- /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 v1.2.3