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Subject[PATCH v4 1/1] xdp: Sample xdp program implementing ip forward
Date
From: Christina Jacob <Christina.Jacob@cavium.com>

Implements port to port forwarding with route table and arp table
lookup for ipv4 packets using bpf_redirect helper function and
lpm_trie map.

Signed-off-by: Christina Jacob <Christina.Jacob@cavium.com>
---
samples/bpf/Makefile | 4 +
samples/bpf/xdp_router_ipv4_kern.c | 186 +++++++++++
samples/bpf/xdp_router_ipv4_user.c | 659 +++++++++++++++++++++++++++++++++++++
3 files changed, 849 insertions(+)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index cf17c79..8504ebb 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -28,6 +28,7 @@ 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
@@ -73,6 +74,7 @@ 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.o \
test_current_task_under_cgroup_user.o
trace_event-objs := bpf_load.o $(LIBBPF) trace_event_user.o
@@ -114,6 +116,7 @@ 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
@@ -160,6 +163,7 @@ 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
diff --git a/samples/bpf/xdp_router_ipv4_kern.c b/samples/bpf/xdp_router_ipv4_kern.c
new file mode 100644
index 0000000..993f56b
--- /dev/null
+++ b/samples/bpf/xdp_router_ipv4_kern.c
@@ -0,0 +1,186 @@
+/* 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";
diff --git a/samples/bpf/xdp_router_ipv4_user.c b/samples/bpf/xdp_router_ipv4_user.c
new file mode 100644
index 0000000..2c1fe3f
--- /dev/null
+++ b/samples/bpf/xdp_router_ipv4_user.c
@@ -0,0 +1,659 @@
+/* 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;
+}
--
2.7.4
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