Add sample for adding simple drop program to link

[deliverable/linux.git] / samples / bpf / xdp1_user.c

diff --git a/samples/bpf/xdp1_user.c b/samples/bpf/xdp1_user.c
new file mode 100644 (file)
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 <linux/bpf.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <assert.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#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;
+}