xdp: Sample xdp program implementing ip forward (3e29cd0e) · Commits · e / devices / android_kernel_fairphone_FP4

samples/bpf/Makefile

+4 −0

Original line number	Diff line number	Diff line
		@@ -29,6 +29,7 @@ hostprogs-y += test_cgrp2_sock
		hostprogs-y += test_cgrp2_sock2
		hostprogs-y += xdp1
		hostprogs-y += xdp2
		hostprogs-y += xdp_router_ipv4
		hostprogs-y += test_current_task_under_cgroup
		hostprogs-y += trace_event
		hostprogs-y += sampleip
		@@ -76,6 +77,7 @@ test_cgrp2_sock2-objs := bpf_load.o $(LIBBPF) test_cgrp2_sock2.o
		xdp1-objs := bpf_load.o $(LIBBPF) xdp1_user.o
		# reuse xdp1 source intentionally
		xdp2-objs := bpf_load.o $(LIBBPF) xdp1_user.o
		xdp_router_ipv4-objs := bpf_load.o $(LIBBPF) xdp_router_ipv4_user.o
		test_current_task_under_cgroup-objs := bpf_load.o $(LIBBPF) $(CGROUP_HELPERS) \
		test_current_task_under_cgroup_user.o
		trace_event-objs := bpf_load.o $(LIBBPF) trace_event_user.o
		@@ -118,6 +120,7 @@ always += parse_varlen.o parse_simple.o parse_ldabs.o
		always += test_cgrp2_tc_kern.o
		always += xdp1_kern.o
		always += xdp2_kern.o
		always += xdp_router_ipv4_kern.o
		always += test_current_task_under_cgroup_kern.o
		always += trace_event_kern.o
		always += sampleip_kern.o
		@@ -166,6 +169,7 @@ HOSTLOADLIBES_map_perf_test += -lelf -lrt
		HOSTLOADLIBES_test_overhead += -lelf -lrt
		HOSTLOADLIBES_xdp1 += -lelf
		HOSTLOADLIBES_xdp2 += -lelf
		HOSTLOADLIBES_xdp_router_ipv4 += -lelf
		HOSTLOADLIBES_test_current_task_under_cgroup += -lelf
		HOSTLOADLIBES_trace_event += -lelf
		HOSTLOADLIBES_sampleip += -lelf

samples/bpf/xdp_router_ipv4_kern.c

0 → 100644

+186 −0

Original line number	Diff line number	Diff line
		/* Copyright (C) 2017 Cavium, Inc.
		*
		* 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 <uapi/linux/bpf.h>
		#include <linux/in.h>
		#include <linux/if_ether.h>
		#include <linux/if_packet.h>
		#include <linux/if_vlan.h>
		#include <linux/ip.h>
		#include <linux/ipv6.h>
		#include "bpf_helpers.h"
		#include <linux/slab.h>
		#include <net/ip_fib.h>

		struct trie_value {
		__u8 prefix[4];
		__be64 value;
		int ifindex;
		int metric;
		__be32 gw;
		};

		/* Key for lpm_trie*/
		union key_4 {
		u32 b32[2];
		u8 b8[8];
		};

		struct arp_entry {
		__be64 mac;
		__be32 dst;
		};

		struct direct_map {
		struct arp_entry arp;
		int ifindex;
		__be64 mac;
		};

		/* Map for trie implementation*/
		struct bpf_map_def SEC("maps") lpm_map = {
		.type = BPF_MAP_TYPE_LPM_TRIE,
		.key_size = 8,
		.value_size = sizeof(struct trie_value),
		.max_entries = 50,
		.map_flags = BPF_F_NO_PREALLOC,
		};

		/* Map for counter*/
		struct bpf_map_def SEC("maps") rxcnt = {
		.type = BPF_MAP_TYPE_PERCPU_ARRAY,
		.key_size = sizeof(u32),
		.value_size = sizeof(u64),
		.max_entries = 256,
		};

		/* Map for ARP table*/
		struct bpf_map_def SEC("maps") arp_table = {
		.type = BPF_MAP_TYPE_HASH,
		.key_size = sizeof(__be32),
		.value_size = sizeof(__be64),
		.max_entries = 50,
		};

		/* Map to keep the exact match entries in the route table*/
		struct bpf_map_def SEC("maps") exact_match = {
		.type = BPF_MAP_TYPE_HASH,
		.key_size = sizeof(__be32),
		.value_size = sizeof(struct direct_map),
		.max_entries = 50,
		};

		struct bpf_map_def SEC("maps") tx_port = {
		.type = BPF_MAP_TYPE_DEVMAP,
		.key_size = sizeof(int),
		.value_size = sizeof(int),
		.max_entries = 100,
		};

		/* Function to set source and destination mac of the packet */
		static inline void set_src_dst_mac(void data, void src, void *dst)
		{
		unsigned short *source = src;
		unsigned short *dest = dst;
		unsigned short *p = data;

		__builtin_memcpy(p, dest, 6);
		__builtin_memcpy(p + 3, source, 6);
		}

		/* Parse IPV4 packet to get SRC, DST IP and protocol */
		static inline int parse_ipv4(void data, u64 nh_off, void data_end,
		__be32 src, __be32 dest)
		{
		struct iphdr *iph = data + nh_off;

		if (iph + 1 > data_end)
		return 0;
		*src = iph->saddr;
		*dest = iph->daddr;
		return iph->protocol;
		}

		SEC("xdp_router_ipv4")
		int xdp_router_ipv4_prog(struct xdp_md *ctx)
		{
		void data_end = (void )(long)ctx->data_end;
		__be64 dest_mac = NULL, src_mac = NULL;
		void data = (void )(long)ctx->data;
		struct trie_value *prefix_value;
		int rc = XDP_DROP, forward_to;
		struct ethhdr *eth = data;
		union key_4 key4;
		long *value;
		u16 h_proto;
		u32 ipproto;
		u64 nh_off;

		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_ARP)) {
		return XDP_PASS;
		} else if (h_proto == htons(ETH_P_IP)) {
		struct direct_map *direct_entry;
		__be32 src_ip = 0, dest_ip = 0;

		ipproto = parse_ipv4(data, nh_off, data_end, &src_ip, &dest_ip);
		direct_entry = bpf_map_lookup_elem(&exact_match, &dest_ip);
		/* Check for exact match, this would give a faster lookup*/
		if (direct_entry && direct_entry->mac && direct_entry->arp.mac) {
		src_mac = &direct_entry->mac;
		dest_mac = &direct_entry->arp.mac;
		forward_to = direct_entry->ifindex;
		} else {
		/* Look up in the trie for lpm*/
		key4.b32[0] = 32;
		key4.b8[4] = dest_ip & 0xff;
		key4.b8[5] = (dest_ip >> 8) & 0xff;
		key4.b8[6] = (dest_ip >> 16) & 0xff;
		key4.b8[7] = (dest_ip >> 24) & 0xff;
		prefix_value = bpf_map_lookup_elem(&lpm_map, &key4);
		if (!prefix_value)
		return XDP_DROP;
		src_mac = &prefix_value->value;
		if (!src_mac)
		return XDP_DROP;
		dest_mac = bpf_map_lookup_elem(&arp_table, &dest_ip);
		if (!dest_mac) {
		if (!prefix_value->gw)
		return XDP_DROP;
		dest_ip = prefix_value->gw;
		dest_mac = bpf_map_lookup_elem(&arp_table, &dest_ip);
		}
		forward_to = prefix_value->ifindex;
		}
		} else {
		ipproto = 0;
		}
		if (src_mac && dest_mac) {
		set_src_dst_mac(data, src_mac, dest_mac);
		value = bpf_map_lookup_elem(&rxcnt, &ipproto);
		if (value)
		*value += 1;
		return bpf_redirect_map(&tx_port, forward_to, 0);
		}
		return rc;
		}

		char _license[] SEC("license") = "GPL";

samples/bpf/xdp_router_ipv4_user.c

0 → 100644

+659 −0

Original line number	Diff line number	Diff line
		/* Copyright (C) 2017 Cavium, Inc.
		*
		* 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"
		#include <arpa/inet.h>
		#include <fcntl.h>
		#include <poll.h>
		#include <net/if.h>
		#include <netdb.h>
		#include <sys/ioctl.h>
		#include <sys/syscall.h>
		#include "bpf_util.h"

		int sock, sock_arp, flags = 0;
		static int total_ifindex;
		int *ifindex_list;
		char buf[8192];

		static int get_route_table(int rtm_family);
		static void int_exit(int sig)
		{
		int i = 0;

		for (i = 0; i < total_ifindex; i++)
		set_link_xdp_fd(ifindex_list[i], -1, flags);
		exit(0);
		}

		static void close_and_exit(int sig)
		{
		int i = 0;

		close(sock);
		close(sock_arp);

		for (i = 0; i < total_ifindex; i++)
		set_link_xdp_fd(ifindex_list[i], -1, flags);
		exit(0);
		}

		/* Get the mac address of the interface given interface name */
		static __be64 getmac(char *iface)
		{
		struct ifreq ifr;
		__be64 mac = 0;
		int fd, i;

		fd = socket(AF_INET, SOCK_DGRAM, 0);
		ifr.ifr_addr.sa_family = AF_INET;
		strncpy(ifr.ifr_name, iface, IFNAMSIZ - 1);
		if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
		printf("ioctl failed leaving....\n");
		return -1;
		}
		for (i = 0; i < 6 ; i++)
		((__u8 )&mac + i) = (__u8)ifr.ifr_hwaddr.sa_data[i];
		close(fd);
		return mac;
		}

		static int recv_msg(struct sockaddr_nl sock_addr, int sock)
		{
		struct nlmsghdr *nh;
		int len, nll = 0;
		char *buf_ptr;

		buf_ptr = buf;
		while (1) {
		len = recv(sock, buf_ptr, sizeof(buf) - nll, 0);
		if (len < 0)
		return len;

		nh = (struct nlmsghdr *)buf_ptr;

		if (nh->nlmsg_type == NLMSG_DONE)
		break;
		buf_ptr += len;
		nll += len;
		if ((sock_addr.nl_groups & RTMGRP_NEIGH) == RTMGRP_NEIGH)
		break;

		if ((sock_addr.nl_groups & RTMGRP_IPV4_ROUTE) == RTMGRP_IPV4_ROUTE)
		break;
		}
		return nll;
		}

		/* Function to parse the route entry returned by netlink
		* Updates the route entry related map entries
		*/
		static void read_route(struct nlmsghdr *nh, int nll)
		{
		char dsts[24], gws[24], ifs[16], dsts_len[24], metrics[24];
		struct bpf_lpm_trie_key *prefix_key;
		struct rtattr *rt_attr;
		struct rtmsg *rt_msg;
		int rtm_family;
		int rtl;
		int i;
		struct route_table {
		int dst_len, iface, metric;
		char *iface_name;
		__be32 dst, gw;
		__be64 mac;
		} route;
		struct arp_table {
		__be64 mac;
		__be32 dst;
		};

		struct direct_map {
		struct arp_table arp;
		int ifindex;
		__be64 mac;
		} direct_entry;

		if (nh->nlmsg_type == RTM_DELROUTE)
		printf("DELETING Route entry\n");
		else if (nh->nlmsg_type == RTM_GETROUTE)
		printf("READING Route entry\n");
		else if (nh->nlmsg_type == RTM_NEWROUTE)
		printf("NEW Route entry\n");
		else
		printf("%d\n", nh->nlmsg_type);

		memset(&route, 0, sizeof(route));
		printf("Destination\t\tGateway\t\tGenmask\t\tMetric\t\tIface\n");
		for (; NLMSG_OK(nh, nll); nh = NLMSG_NEXT(nh, nll)) {
		rt_msg = (struct rtmsg *)NLMSG_DATA(nh);
		rtm_family = rt_msg->rtm_family;
		if (rtm_family == AF_INET)
		if (rt_msg->rtm_table != RT_TABLE_MAIN)
		continue;
		rt_attr = (struct rtattr *)RTM_RTA(rt_msg);
		rtl = RTM_PAYLOAD(nh);

		for (; RTA_OK(rt_attr, rtl); rt_attr = RTA_NEXT(rt_attr, rtl)) {
		switch (rt_attr->rta_type) {
		case NDA_DST:
		sprintf(dsts, "%u",
		(((__be32 )RTA_DATA(rt_attr))));
		break;
		case RTA_GATEWAY:
		sprintf(gws, "%u",
		((__be32 )RTA_DATA(rt_attr)));
		break;
		case RTA_OIF:
		sprintf(ifs, "%u",
		((int )RTA_DATA(rt_attr)));
		break;
		case RTA_METRICS:
		sprintf(metrics, "%u",
		((int )RTA_DATA(rt_attr)));
		default:
		break;
		}
		}
		sprintf(dsts_len, "%d", rt_msg->rtm_dst_len);
		route.dst = atoi(dsts);
		route.dst_len = atoi(dsts_len);
		route.gw = atoi(gws);
		route.iface = atoi(ifs);
		route.metric = atoi(metrics);
		route.iface_name = alloca(sizeof(char ) IFNAMSIZ);
		route.iface_name = if_indextoname(route.iface, route.iface_name);
		route.mac = getmac(route.iface_name);
		if (route.mac == -1) {
		int i = 0;

		for (i = 0; i < total_ifindex; i++)
		set_link_xdp_fd(ifindex_list[i], -1, flags);
		exit(0);
		}
		assert(bpf_map_update_elem(map_fd[4], &route.iface, &route.iface, 0) == 0);
		if (rtm_family == AF_INET) {
		struct trie_value {
		__u8 prefix[4];
		__be64 value;
		int ifindex;
		int metric;
		__be32 gw;
		} *prefix_value;

		prefix_key = alloca(sizeof(*prefix_key) + 3);
		prefix_value = alloca(sizeof(*prefix_value));

		prefix_key->prefixlen = 32;
		prefix_key->prefixlen = route.dst_len;
		direct_entry.mac = route.mac & 0xffffffffffff;
		direct_entry.ifindex = route.iface;
		direct_entry.arp.mac = 0;
		direct_entry.arp.dst = 0;
		if (route.dst_len == 32) {
		if (nh->nlmsg_type == RTM_DELROUTE)
		assert(bpf_map_delete_elem(map_fd[3], &route.dst) == 0);
		else
		if (bpf_map_lookup_elem(map_fd[2], &route.dst, &direct_entry.arp.mac) == 0)
		direct_entry.arp.dst = route.dst;
		assert(bpf_map_update_elem(map_fd[3], &route.dst, &direct_entry, 0) == 0);
		}
		for (i = 0; i < 4; i++)
		prefix_key->data[i] = (route.dst >> i * 8) & 0xff;

		printf("%3d.%d.%d.%d\t\t%3x\t\t%d\t\t%d\t\t%s\n",
		(int)prefix_key->data[0],
		(int)prefix_key->data[1],
		(int)prefix_key->data[2],
		(int)prefix_key->data[3],
		route.gw, route.dst_len,
		route.metric,
		route.iface_name);
		if (bpf_map_lookup_elem(map_fd[0], prefix_key,
		prefix_value) < 0) {
		for (i = 0; i < 4; i++)
		prefix_value->prefix[i] = prefix_key->data[i];
		prefix_value->value = route.mac & 0xffffffffffff;
		prefix_value->ifindex = route.iface;
		prefix_value->gw = route.gw;
		prefix_value->metric = route.metric;

		assert(bpf_map_update_elem(map_fd[0],
		prefix_key,
		prefix_value, 0
		) == 0);
		} else {
		if (nh->nlmsg_type == RTM_DELROUTE) {
		printf("deleting entry\n");
		printf("prefix key=%d.%d.%d.%d/%d",
		prefix_key->data[0],
		prefix_key->data[1],
		prefix_key->data[2],
		prefix_key->data[3],
		prefix_key->prefixlen);
		assert(bpf_map_delete_elem(map_fd[0],
		prefix_key
		) == 0);
		/* Rereading the route table to check if
		* there is an entry with the same
		* prefix but a different metric as the
		* deleted enty.
		*/
		get_route_table(AF_INET);
		} else if (prefix_key->data[0] ==
		prefix_value->prefix[0] &&
		prefix_key->data[1] ==
		prefix_value->prefix[1] &&
		prefix_key->data[2] ==
		prefix_value->prefix[2] &&
		prefix_key->data[3] ==
		prefix_value->prefix[3] &&
		route.metric >= prefix_value->metric) {
		continue;
		} else {
		for (i = 0; i < 4; i++)
		prefix_value->prefix[i] =
		prefix_key->data[i];
		prefix_value->value =
		route.mac & 0xffffffffffff;
		prefix_value->ifindex = route.iface;
		prefix_value->gw = route.gw;
		prefix_value->metric = route.metric;
		assert(bpf_map_update_elem(
		map_fd[0],
		prefix_key,
		prefix_value,
		0) == 0);
		}
		}
		}
		memset(&route, 0, sizeof(route));
		memset(dsts, 0, sizeof(dsts));
		memset(dsts_len, 0, sizeof(dsts_len));
		memset(gws, 0, sizeof(gws));
		memset(ifs, 0, sizeof(ifs));
		memset(&route, 0, sizeof(route));
		}
		}

		/* Function to read the existing route table when the process is launched*/
		static int get_route_table(int rtm_family)
		{
		struct sockaddr_nl sa;
		struct nlmsghdr *nh;
		int sock, seq = 0;
		struct msghdr msg;
		struct iovec iov;
		int ret = 0;
		int nll;

		struct {
		struct nlmsghdr nl;
		struct rtmsg rt;
		char buf[8192];
		} req;

		sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
		if (sock < 0) {
		printf("open netlink socket: %s\n", strerror(errno));
		return -1;
		}
		memset(&sa, 0, sizeof(sa));
		sa.nl_family = AF_NETLINK;
		if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
		printf("bind to netlink: %s\n", strerror(errno));
		ret = -1;
		goto cleanup;
		}
		memset(&req, 0, sizeof(req));
		req.nl.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
		req.nl.nlmsg_flags = NLM_F_REQUEST \| NLM_F_DUMP;
		req.nl.nlmsg_type = RTM_GETROUTE;

		req.rt.rtm_family = rtm_family;
		req.rt.rtm_table = RT_TABLE_MAIN;
		req.nl.nlmsg_pid = 0;
		req.nl.nlmsg_seq = ++seq;
		memset(&msg, 0, sizeof(msg));
		iov.iov_base = (void *)&req.nl;
		iov.iov_len = req.nl.nlmsg_len;
		msg.msg_iov = &iov;
		msg.msg_iovlen = 1;
		ret = sendmsg(sock, &msg, 0);
		if (ret < 0) {
		printf("send to netlink: %s\n", strerror(errno));
		ret = -1;
		goto cleanup;
		}
		memset(buf, 0, sizeof(buf));
		nll = recv_msg(sa, sock);
		if (nll < 0) {
		printf("recv from netlink: %s\n", strerror(nll));
		ret = -1;
		goto cleanup;
		}
		nh = (struct nlmsghdr *)buf;
		read_route(nh, nll);
		cleanup:
		close(sock);
		return ret;
		}

		/* Function to parse the arp entry returned by netlink
		* Updates the arp entry related map entries
		*/
		static void read_arp(struct nlmsghdr *nh, int nll)
		{
		struct rtattr *rt_attr;
		char dsts[24], mac[24];
		struct ndmsg *rt_msg;
		int rtl, ndm_family;

		struct arp_table {
		__be64 mac;
		__be32 dst;
		} arp_entry;
		struct direct_map {
		struct arp_table arp;
		int ifindex;
		__be64 mac;
		} direct_entry;

		if (nh->nlmsg_type == RTM_GETNEIGH)
		printf("READING arp entry\n");
		printf("Address\tHwAddress\n");
		for (; NLMSG_OK(nh, nll); nh = NLMSG_NEXT(nh, nll)) {
		rt_msg = (struct ndmsg *)NLMSG_DATA(nh);
		rt_attr = (struct rtattr *)RTM_RTA(rt_msg);
		ndm_family = rt_msg->ndm_family;
		rtl = RTM_PAYLOAD(nh);
		for (; RTA_OK(rt_attr, rtl); rt_attr = RTA_NEXT(rt_attr, rtl)) {
		switch (rt_attr->rta_type) {
		case NDA_DST:
		sprintf(dsts, "%u",
		((__be32 )RTA_DATA(rt_attr)));
		break;
		case NDA_LLADDR:
		sprintf(mac, "%lld",
		((__be64 )RTA_DATA(rt_attr)));
		break;
		default:
		break;
		}
		}
		arp_entry.dst = atoi(dsts);
		arp_entry.mac = atol(mac);
		printf("%x\t\t%llx\n", arp_entry.dst, arp_entry.mac);
		if (ndm_family == AF_INET) {
		if (bpf_map_lookup_elem(map_fd[3], &arp_entry.dst,
		&direct_entry) == 0) {
		if (nh->nlmsg_type == RTM_DELNEIGH) {
		direct_entry.arp.dst = 0;
		direct_entry.arp.mac = 0;
		} else if (nh->nlmsg_type == RTM_NEWNEIGH) {
		direct_entry.arp.dst = arp_entry.dst;
		direct_entry.arp.mac = arp_entry.mac;
		}
		assert(bpf_map_update_elem(map_fd[3],
		&arp_entry.dst,
		&direct_entry, 0
		) == 0);
		memset(&direct_entry, 0, sizeof(direct_entry));
		}
		if (nh->nlmsg_type == RTM_DELNEIGH) {
		assert(bpf_map_delete_elem(map_fd[2], &arp_entry.dst) == 0);
		} else if (nh->nlmsg_type == RTM_NEWNEIGH) {
		assert(bpf_map_update_elem(map_fd[2],
		&arp_entry.dst,
		&arp_entry.mac, 0
		) == 0);
		}
		}
		memset(&arp_entry, 0, sizeof(arp_entry));
		memset(dsts, 0, sizeof(dsts));
		}
		}

		/* Function to read the existing arp table when the process is launched*/
		static int get_arp_table(int rtm_family)
		{
		struct sockaddr_nl sa;
		struct nlmsghdr *nh;
		int sock, seq = 0;
		struct msghdr msg;
		struct iovec iov;
		int ret = 0;
		int nll;
		struct {
		struct nlmsghdr nl;
		struct ndmsg rt;
		char buf[8192];
		} req;

		sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
		if (sock < 0) {
		printf("open netlink socket: %s\n", strerror(errno));
		return -1;
		}
		memset(&sa, 0, sizeof(sa));
		sa.nl_family = AF_NETLINK;
		if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
		printf("bind to netlink: %s\n", strerror(errno));
		ret = -1;
		goto cleanup;
		}
		memset(&req, 0, sizeof(req));
		req.nl.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
		req.nl.nlmsg_flags = NLM_F_REQUEST \| NLM_F_DUMP;
		req.nl.nlmsg_type = RTM_GETNEIGH;
		req.rt.ndm_state = NUD_REACHABLE;
		req.rt.ndm_family = rtm_family;
		req.nl.nlmsg_pid = 0;
		req.nl.nlmsg_seq = ++seq;
		memset(&msg, 0, sizeof(msg));
		iov.iov_base = (void *)&req.nl;
		iov.iov_len = req.nl.nlmsg_len;
		msg.msg_iov = &iov;
		msg.msg_iovlen = 1;
		ret = sendmsg(sock, &msg, 0);
		if (ret < 0) {
		printf("send to netlink: %s\n", strerror(errno));
		ret = -1;
		goto cleanup;
		}
		memset(buf, 0, sizeof(buf));
		nll = recv_msg(sa, sock);
		if (nll < 0) {
		printf("recv from netlink: %s\n", strerror(nll));
		ret = -1;
		goto cleanup;
		}
		nh = (struct nlmsghdr *)buf;
		read_arp(nh, nll);
		cleanup:
		close(sock);
		return ret;
		}

		/* Function to keep track and update changes in route and arp table
		* Give regular statistics of packets forwarded
		*/
		static int monitor_route(void)
		{
		unsigned int nr_cpus = bpf_num_possible_cpus();
		const unsigned int nr_keys = 256;
		struct pollfd fds_route, fds_arp;
		__u64 prev[nr_keys][nr_cpus];
		struct sockaddr_nl la, lr;
		__u64 values[nr_cpus];
		struct nlmsghdr *nh;
		int nll, ret = 0;
		int interval = 5;
		__u32 key;
		int i;

		sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
		if (sock < 0) {
		printf("open netlink socket: %s\n", strerror(errno));
		return -1;
		}

		fcntl(sock, F_SETFL, O_NONBLOCK);
		memset(&lr, 0, sizeof(lr));
		lr.nl_family = AF_NETLINK;
		lr.nl_groups = RTMGRP_IPV6_ROUTE \| RTMGRP_IPV4_ROUTE \| RTMGRP_NOTIFY;
		if (bind(sock, (struct sockaddr *)&lr, sizeof(lr)) < 0) {
		printf("bind to netlink: %s\n", strerror(errno));
		ret = -1;
		goto cleanup;
		}
		fds_route.fd = sock;
		fds_route.events = POLL_IN;

		sock_arp = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
		if (sock_arp < 0) {
		printf("open netlink socket: %s\n", strerror(errno));
		return -1;
		}

		fcntl(sock_arp, F_SETFL, O_NONBLOCK);
		memset(&la, 0, sizeof(la));
		la.nl_family = AF_NETLINK;
		la.nl_groups = RTMGRP_NEIGH \| RTMGRP_NOTIFY;
		if (bind(sock_arp, (struct sockaddr *)&la, sizeof(la)) < 0) {
		printf("bind to netlink: %s\n", strerror(errno));
		ret = -1;
		goto cleanup;
		}
		fds_arp.fd = sock_arp;
		fds_arp.events = POLL_IN;

		memset(prev, 0, sizeof(prev));
		do {
		signal(SIGINT, close_and_exit);
		signal(SIGTERM, close_and_exit);

		sleep(interval);
		for (key = 0; key < nr_keys; key++) {
		__u64 sum = 0;

		assert(bpf_map_lookup_elem(map_fd[1], &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));
		}

		memset(buf, 0, sizeof(buf));
		if (poll(&fds_route, 1, 3) == POLL_IN) {
		nll = recv_msg(lr, sock);
		if (nll < 0) {
		printf("recv from netlink: %s\n", strerror(nll));
		ret = -1;
		goto cleanup;
		}

		nh = (struct nlmsghdr *)buf;
		printf("Routing table updated.\n");
		read_route(nh, nll);
		}
		memset(buf, 0, sizeof(buf));
		if (poll(&fds_arp, 1, 3) == POLL_IN) {
		nll = recv_msg(la, sock_arp);
		if (nll < 0) {
		printf("recv from netlink: %s\n", strerror(nll));
		ret = -1;
		goto cleanup;
		}

		nh = (struct nlmsghdr *)buf;
		read_arp(nh, nll);
		}

		} while (1);
		cleanup:
		close(sock);
		return ret;
		}

		int main(int ac, char **argv)
		{
		char filename[256];
		char **ifname_list;
		int i = 1;

		snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
		if (ac < 2) {
		printf("usage: %s [-S] Interface name list\n", argv[0]);
		return 1;
		}
		if (!strcmp(argv[1], "-S")) {
		flags = XDP_FLAGS_SKB_MODE;
		total_ifindex = ac - 2;
		ifname_list = (argv + 2);
		} else {
		flags = 0;
		total_ifindex = ac - 1;
		ifname_list = (argv + 1);
		}
		if (load_bpf_file(filename)) {
		printf("%s", bpf_log_buf);
		return 1;
		}
		printf("\n************loading bpf file*******************\n\n\n");
		if (!prog_fd[0]) {
		printf("load_bpf_file: %s\n", strerror(errno));
		return 1;
		}
		ifindex_list = (int )malloc(total_ifindex sizeof(int *));
		for (i = 0; i < total_ifindex; i++) {
		ifindex_list[i] = if_nametoindex(ifname_list[i]);
		if (!ifindex_list[i]) {
		printf("Couldn't translate interface name: %s",
		strerror(errno));
		return 1;
		}
		}
		for (i = 0; i < total_ifindex; i++) {
		if (set_link_xdp_fd(ifindex_list[i], prog_fd[0], flags) < 0) {
		printf("link set xdp fd failed\n");
		int recovery_index = i;

		for (i = 0; i < recovery_index; i++)
		set_link_xdp_fd(ifindex_list[i], -1, flags);

		return 1;
		}
		printf("Attached to %d\n", ifindex_list[i]);
		}
		signal(SIGINT, int_exit);
		signal(SIGTERM, int_exit);

		printf("*****************ROUTE TABLE***********************\n\n\n");
		get_route_table(AF_INET);
		printf("*****************ARP TABLE*************************\n\n\n");
		get_arp_table(AF_INET);
		if (monitor_route() < 0) {
		printf("Error in receiving route update");
		return 1;
		}

		return 0;
		}