diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 91ee3643ccc8..bf04a46f6d5b 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3354,6 +3354,21 @@ int dev_forward_skb(struct net_device *dev, struct sk_buff *skb); bool is_skb_forwardable(const struct net_device *dev, const struct sk_buff *skb); +static __always_inline int ____dev_forward_skb(struct net_device *dev, + struct sk_buff *skb) +{ + if (skb_orphan_frags(skb, GFP_ATOMIC) || + unlikely(!is_skb_forwardable(dev, skb))) { + atomic_long_inc(&dev->rx_dropped); + kfree_skb(skb); + return NET_RX_DROP; + } + + skb_scrub_packet(skb, true); + skb->priority = 0; + return 0; +} + void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev); extern int netdev_budget; diff --git a/net/core/dev.c b/net/core/dev.c index eaad4c28069f..6666b28b6815 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1766,19 +1766,14 @@ EXPORT_SYMBOL_GPL(is_skb_forwardable); int __dev_forward_skb(struct net_device *dev, struct sk_buff *skb) { - if (skb_orphan_frags(skb, GFP_ATOMIC) || - unlikely(!is_skb_forwardable(dev, skb))) { - atomic_long_inc(&dev->rx_dropped); - kfree_skb(skb); - return NET_RX_DROP; + int ret = ____dev_forward_skb(dev, skb); + + if (likely(!ret)) { + skb->protocol = eth_type_trans(skb, dev); + skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN); } - skb_scrub_packet(skb, true); - skb->priority = 0; - skb->protocol = eth_type_trans(skb, dev); - skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN); - - return 0; + return ret; } EXPORT_SYMBOL_GPL(__dev_forward_skb); diff --git a/net/core/filter.c b/net/core/filter.c index 00351cdf7d0c..b391209838ef 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1628,6 +1628,19 @@ static inline int __bpf_rx_skb(struct net_device *dev, struct sk_buff *skb) return dev_forward_skb(dev, skb); } +static inline int __bpf_rx_skb_no_mac(struct net_device *dev, + struct sk_buff *skb) +{ + int ret = ____dev_forward_skb(dev, skb); + + if (likely(!ret)) { + skb->dev = dev; + ret = netif_rx(skb); + } + + return ret; +} + static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb) { int ret; @@ -1647,6 +1660,51 @@ static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb) return ret; } +static int __bpf_redirect_no_mac(struct sk_buff *skb, struct net_device *dev, + u32 flags) +{ + /* skb->mac_len is not set on normal egress */ + unsigned int mlen = skb->network_header - skb->mac_header; + + __skb_pull(skb, mlen); + + /* At ingress, the mac header has already been pulled once. + * At egress, skb_pospull_rcsum has to be done in case that + * the skb is originated from ingress (i.e. a forwarded skb) + * to ensure that rcsum starts at net header. + */ + if (!skb_at_tc_ingress(skb)) + skb_postpull_rcsum(skb, skb_mac_header(skb), mlen); + skb_pop_mac_header(skb); + skb_reset_mac_len(skb); + return flags & BPF_F_INGRESS ? + __bpf_rx_skb_no_mac(dev, skb) : __bpf_tx_skb(dev, skb); +} + +static int __bpf_redirect_common(struct sk_buff *skb, struct net_device *dev, + u32 flags) +{ + bpf_push_mac_rcsum(skb); + return flags & BPF_F_INGRESS ? + __bpf_rx_skb(dev, skb) : __bpf_tx_skb(dev, skb); +} + +static int __bpf_redirect(struct sk_buff *skb, struct net_device *dev, + u32 flags) +{ + switch (dev->type) { + case ARPHRD_TUNNEL: + case ARPHRD_TUNNEL6: + case ARPHRD_SIT: + case ARPHRD_IPGRE: + case ARPHRD_VOID: + case ARPHRD_NONE: + return __bpf_redirect_no_mac(skb, dev, flags); + default: + return __bpf_redirect_common(skb, dev, flags); + } +} + BPF_CALL_3(bpf_clone_redirect, struct sk_buff *, skb, u32, ifindex, u64, flags) { struct net_device *dev; @@ -1675,10 +1733,7 @@ BPF_CALL_3(bpf_clone_redirect, struct sk_buff *, skb, u32, ifindex, u64, flags) return -ENOMEM; } - bpf_push_mac_rcsum(clone); - - return flags & BPF_F_INGRESS ? - __bpf_rx_skb(dev, clone) : __bpf_tx_skb(dev, clone); + return __bpf_redirect(clone, dev, flags); } static const struct bpf_func_proto bpf_clone_redirect_proto = { @@ -1722,10 +1777,7 @@ int skb_do_redirect(struct sk_buff *skb) return -EINVAL; } - bpf_push_mac_rcsum(skb); - - return ri->flags & BPF_F_INGRESS ? - __bpf_rx_skb(dev, skb) : __bpf_tx_skb(dev, skb); + return __bpf_redirect(skb, dev, ri->flags); } static const struct bpf_func_proto bpf_redirect_proto = { diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 12b7304d55dc..72c58675973e 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -27,6 +27,7 @@ hostprogs-y += xdp2 hostprogs-y += test_current_task_under_cgroup hostprogs-y += trace_event hostprogs-y += sampleip +hostprogs-y += tc_l2_redirect test_verifier-objs := test_verifier.o libbpf.o test_maps-objs := test_maps.o libbpf.o @@ -56,6 +57,7 @@ test_current_task_under_cgroup-objs := bpf_load.o libbpf.o \ test_current_task_under_cgroup_user.o trace_event-objs := bpf_load.o libbpf.o trace_event_user.o sampleip-objs := bpf_load.o libbpf.o sampleip_user.o +tc_l2_redirect-objs := bpf_load.o libbpf.o tc_l2_redirect_user.o # Tell kbuild to always build the programs always := $(hostprogs-y) @@ -72,6 +74,7 @@ always += test_probe_write_user_kern.o always += trace_output_kern.o always += tcbpf1_kern.o always += tcbpf2_kern.o +always += tc_l2_redirect_kern.o always += lathist_kern.o always += offwaketime_kern.o always += spintest_kern.o @@ -111,6 +114,7 @@ HOSTLOADLIBES_xdp2 += -lelf HOSTLOADLIBES_test_current_task_under_cgroup += -lelf HOSTLOADLIBES_trace_event += -lelf HOSTLOADLIBES_sampleip += -lelf +HOSTLOADLIBES_tc_l2_redirect += -l elf # 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/tc_l2_redirect.sh b/samples/bpf/tc_l2_redirect.sh new file mode 100755 index 000000000000..80a05591a140 --- /dev/null +++ b/samples/bpf/tc_l2_redirect.sh @@ -0,0 +1,173 @@ +#!/bin/bash + +[[ -z $TC ]] && TC='tc' +[[ -z $IP ]] && IP='ip' + +REDIRECT_USER='./tc_l2_redirect' +REDIRECT_BPF='./tc_l2_redirect_kern.o' + +RP_FILTER=$(< /proc/sys/net/ipv4/conf/all/rp_filter) +IPV6_FORWARDING=$(< /proc/sys/net/ipv6/conf/all/forwarding) + +function config_common { + local tun_type=$1 + + $IP netns add ns1 + $IP netns add ns2 + $IP link add ve1 type veth peer name vens1 + $IP link add ve2 type veth peer name vens2 + $IP link set dev ve1 up + $IP link set dev ve2 up + $IP link set dev ve1 mtu 1500 + $IP link set dev ve2 mtu 1500 + $IP link set dev vens1 netns ns1 + $IP link set dev vens2 netns ns2 + + $IP -n ns1 link set dev lo up + $IP -n ns1 link set dev vens1 up + $IP -n ns1 addr add 10.1.1.101/24 dev vens1 + $IP -n ns1 addr add 2401:db01::65/64 dev vens1 nodad + $IP -n ns1 route add default via 10.1.1.1 dev vens1 + $IP -n ns1 route add default via 2401:db01::1 dev vens1 + + $IP -n ns2 link set dev lo up + $IP -n ns2 link set dev vens2 up + $IP -n ns2 addr add 10.2.1.102/24 dev vens2 + $IP -n ns2 addr add 2401:db02::66/64 dev vens2 nodad + $IP -n ns2 addr add 10.10.1.102 dev lo + $IP -n ns2 addr add 2401:face::66/64 dev lo nodad + $IP -n ns2 link add ipt2 type ipip local 10.2.1.102 remote 10.2.1.1 + $IP -n ns2 link add ip6t2 type ip6tnl mode any local 2401:db02::66 remote 2401:db02::1 + $IP -n ns2 link set dev ipt2 up + $IP -n ns2 link set dev ip6t2 up + $IP netns exec ns2 $TC qdisc add dev vens2 clsact + $IP netns exec ns2 $TC filter add dev vens2 ingress bpf da obj $REDIRECT_BPF sec drop_non_tun_vip + if [[ $tun_type == "ipip" ]]; then + $IP -n ns2 route add 10.1.1.0/24 dev ipt2 + $IP netns exec ns2 sysctl -q -w net.ipv4.conf.all.rp_filter=0 + $IP netns exec ns2 sysctl -q -w net.ipv4.conf.ipt2.rp_filter=0 + else + $IP -n ns2 route add 10.1.1.0/24 dev ip6t2 + $IP -n ns2 route add 2401:db01::/64 dev ip6t2 + $IP netns exec ns2 sysctl -q -w net.ipv4.conf.all.rp_filter=0 + $IP netns exec ns2 sysctl -q -w net.ipv4.conf.ip6t2.rp_filter=0 + fi + + $IP addr add 10.1.1.1/24 dev ve1 + $IP addr add 2401:db01::1/64 dev ve1 nodad + $IP addr add 10.2.1.1/24 dev ve2 + $IP addr add 2401:db02::1/64 dev ve2 nodad + + $TC qdisc add dev ve2 clsact + $TC filter add dev ve2 ingress bpf da obj $REDIRECT_BPF sec l2_to_iptun_ingress_forward + + sysctl -q -w net.ipv4.conf.all.rp_filter=0 + sysctl -q -w net.ipv6.conf.all.forwarding=1 +} + +function cleanup { + set +e + [[ -z $DEBUG ]] || set +x + $IP netns delete ns1 >& /dev/null + $IP netns delete ns2 >& /dev/null + $IP link del ve1 >& /dev/null + $IP link del ve2 >& /dev/null + $IP link del ipt >& /dev/null + $IP link del ip6t >& /dev/null + sysctl -q -w net.ipv4.conf.all.rp_filter=$RP_FILTER + sysctl -q -w net.ipv6.conf.all.forwarding=$IPV6_FORWARDING + rm -f /sys/fs/bpf/tc/globals/tun_iface + [[ -z $DEBUG ]] || set -x + set -e +} + +function l2_to_ipip { + echo -n "l2_to_ipip $1: " + + local dir=$1 + + config_common ipip + + $IP link add ipt type ipip external + $IP link set dev ipt up + sysctl -q -w net.ipv4.conf.ipt.rp_filter=0 + sysctl -q -w net.ipv4.conf.ipt.forwarding=1 + + if [[ $dir == "egress" ]]; then + $IP route add 10.10.1.0/24 via 10.2.1.102 dev ve2 + $TC filter add dev ve2 egress bpf da obj $REDIRECT_BPF sec l2_to_iptun_ingress_redirect + sysctl -q -w net.ipv4.conf.ve1.forwarding=1 + else + $TC qdisc add dev ve1 clsact + $TC filter add dev ve1 ingress bpf da obj $REDIRECT_BPF sec l2_to_iptun_ingress_redirect + fi + + $REDIRECT_USER -U /sys/fs/bpf/tc/globals/tun_iface -i $(< /sys/class/net/ipt/ifindex) + + $IP netns exec ns1 ping -c1 10.10.1.102 >& /dev/null + + if [[ $dir == "egress" ]]; then + # test direct egress to ve2 (i.e. not forwarding from + # ve1 to ve2). + ping -c1 10.10.1.102 >& /dev/null + fi + + cleanup + + echo "OK" +} + +function l2_to_ip6tnl { + echo -n "l2_to_ip6tnl $1: " + + local dir=$1 + + config_common ip6tnl + + $IP link add ip6t type ip6tnl mode any external + $IP link set dev ip6t up + sysctl -q -w net.ipv4.conf.ip6t.rp_filter=0 + sysctl -q -w net.ipv4.conf.ip6t.forwarding=1 + + if [[ $dir == "egress" ]]; then + $IP route add 10.10.1.0/24 via 10.2.1.102 dev ve2 + $IP route add 2401:face::/64 via 2401:db02::66 dev ve2 + $TC filter add dev ve2 egress bpf da obj $REDIRECT_BPF sec l2_to_ip6tun_ingress_redirect + sysctl -q -w net.ipv4.conf.ve1.forwarding=1 + else + $TC qdisc add dev ve1 clsact + $TC filter add dev ve1 ingress bpf da obj $REDIRECT_BPF sec l2_to_ip6tun_ingress_redirect + fi + + $REDIRECT_USER -U /sys/fs/bpf/tc/globals/tun_iface -i $(< /sys/class/net/ip6t/ifindex) + + $IP netns exec ns1 ping -c1 10.10.1.102 >& /dev/null + $IP netns exec ns1 ping -6 -c1 2401:face::66 >& /dev/null + + if [[ $dir == "egress" ]]; then + # test direct egress to ve2 (i.e. not forwarding from + # ve1 to ve2). + ping -c1 10.10.1.102 >& /dev/null + ping -6 -c1 2401:face::66 >& /dev/null + fi + + cleanup + + echo "OK" +} + +cleanup +test_names="l2_to_ipip l2_to_ip6tnl" +test_dirs="ingress egress" +if [[ $# -ge 2 ]]; then + test_names=$1 + test_dirs=$2 +elif [[ $# -ge 1 ]]; then + test_names=$1 +fi + +for t in $test_names; do + for d in $test_dirs; do + $t $d + done +done diff --git a/samples/bpf/tc_l2_redirect_kern.c b/samples/bpf/tc_l2_redirect_kern.c new file mode 100644 index 000000000000..92a44729dbe4 --- /dev/null +++ b/samples/bpf/tc_l2_redirect_kern.c @@ -0,0 +1,236 @@ +/* Copyright (c) 2016 Facebook + * + * 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 "bpf_helpers.h" + +#define _htonl __builtin_bswap32 + +#define PIN_GLOBAL_NS 2 +struct bpf_elf_map { + __u32 type; + __u32 size_key; + __u32 size_value; + __u32 max_elem; + __u32 flags; + __u32 id; + __u32 pinning; +}; + +/* copy of 'struct ethhdr' without __packed */ +struct eth_hdr { + unsigned char h_dest[ETH_ALEN]; + unsigned char h_source[ETH_ALEN]; + unsigned short h_proto; +}; + +struct bpf_elf_map SEC("maps") tun_iface = { + .type = BPF_MAP_TYPE_ARRAY, + .size_key = sizeof(int), + .size_value = sizeof(int), + .pinning = PIN_GLOBAL_NS, + .max_elem = 1, +}; + +static __always_inline bool is_vip_addr(__be16 eth_proto, __be32 daddr) +{ + if (eth_proto == htons(ETH_P_IP)) + return (_htonl(0xffffff00) & daddr) == _htonl(0x0a0a0100); + else if (eth_proto == htons(ETH_P_IPV6)) + return (daddr == _htonl(0x2401face)); + + return false; +} + +SEC("l2_to_iptun_ingress_forward") +int _l2_to_iptun_ingress_forward(struct __sk_buff *skb) +{ + struct bpf_tunnel_key tkey = {}; + void *data = (void *)(long)skb->data; + struct eth_hdr *eth = data; + void *data_end = (void *)(long)skb->data_end; + int key = 0, *ifindex; + + int ret; + + if (data + sizeof(*eth) > data_end) + return TC_ACT_OK; + + ifindex = bpf_map_lookup_elem(&tun_iface, &key); + if (!ifindex) + return TC_ACT_OK; + + if (eth->h_proto == htons(ETH_P_IP)) { + char fmt4[] = "ingress forward to ifindex:%d daddr4:%x\n"; + struct iphdr *iph = data + sizeof(*eth); + + if (data + sizeof(*eth) + sizeof(*iph) > data_end) + return TC_ACT_OK; + + if (iph->protocol != IPPROTO_IPIP) + return TC_ACT_OK; + + bpf_trace_printk(fmt4, sizeof(fmt4), *ifindex, + _htonl(iph->daddr)); + return bpf_redirect(*ifindex, BPF_F_INGRESS); + } else if (eth->h_proto == htons(ETH_P_IPV6)) { + char fmt6[] = "ingress forward to ifindex:%d daddr6:%x::%x\n"; + struct ipv6hdr *ip6h = data + sizeof(*eth); + + if (data + sizeof(*eth) + sizeof(*ip6h) > data_end) + return TC_ACT_OK; + + if (ip6h->nexthdr != IPPROTO_IPIP && + ip6h->nexthdr != IPPROTO_IPV6) + return TC_ACT_OK; + + bpf_trace_printk(fmt6, sizeof(fmt6), *ifindex, + _htonl(ip6h->daddr.s6_addr32[0]), + _htonl(ip6h->daddr.s6_addr32[3])); + return bpf_redirect(*ifindex, BPF_F_INGRESS); + } + + return TC_ACT_OK; +} + +SEC("l2_to_iptun_ingress_redirect") +int _l2_to_iptun_ingress_redirect(struct __sk_buff *skb) +{ + struct bpf_tunnel_key tkey = {}; + void *data = (void *)(long)skb->data; + struct eth_hdr *eth = data; + void *data_end = (void *)(long)skb->data_end; + int key = 0, *ifindex; + + int ret; + + if (data + sizeof(*eth) > data_end) + return TC_ACT_OK; + + ifindex = bpf_map_lookup_elem(&tun_iface, &key); + if (!ifindex) + return TC_ACT_OK; + + if (eth->h_proto == htons(ETH_P_IP)) { + char fmt4[] = "e/ingress redirect daddr4:%x to ifindex:%d\n"; + struct iphdr *iph = data + sizeof(*eth); + __be32 daddr = iph->daddr; + + if (data + sizeof(*eth) + sizeof(*iph) > data_end) + return TC_ACT_OK; + + if (!is_vip_addr(eth->h_proto, daddr)) + return TC_ACT_OK; + + bpf_trace_printk(fmt4, sizeof(fmt4), _htonl(daddr), *ifindex); + } else { + return TC_ACT_OK; + } + + tkey.tunnel_id = 10000; + tkey.tunnel_ttl = 64; + tkey.remote_ipv4 = 0x0a020166; /* 10.2.1.102 */ + bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), 0); + return bpf_redirect(*ifindex, 0); +} + +SEC("l2_to_ip6tun_ingress_redirect") +int _l2_to_ip6tun_ingress_redirect(struct __sk_buff *skb) +{ + struct bpf_tunnel_key tkey = {}; + void *data = (void *)(long)skb->data; + struct eth_hdr *eth = data; + void *data_end = (void *)(long)skb->data_end; + int key = 0, *ifindex; + + if (data + sizeof(*eth) > data_end) + return TC_ACT_OK; + + ifindex = bpf_map_lookup_elem(&tun_iface, &key); + if (!ifindex) + return TC_ACT_OK; + + if (eth->h_proto == htons(ETH_P_IP)) { + char fmt4[] = "e/ingress redirect daddr4:%x to ifindex:%d\n"; + struct iphdr *iph = data + sizeof(*eth); + + if (data + sizeof(*eth) + sizeof(*iph) > data_end) + return TC_ACT_OK; + + if (!is_vip_addr(eth->h_proto, iph->daddr)) + return TC_ACT_OK; + + bpf_trace_printk(fmt4, sizeof(fmt4), _htonl(iph->daddr), + *ifindex); + } else if (eth->h_proto == htons(ETH_P_IPV6)) { + char fmt6[] = "e/ingress redirect daddr6:%x to ifindex:%d\n"; + struct ipv6hdr *ip6h = data + sizeof(*eth); + + if (data + sizeof(*eth) + sizeof(*ip6h) > data_end) + return TC_ACT_OK; + + if (!is_vip_addr(eth->h_proto, ip6h->daddr.s6_addr32[0])) + return TC_ACT_OK; + + bpf_trace_printk(fmt6, sizeof(fmt6), + _htonl(ip6h->daddr.s6_addr32[0]), *ifindex); + } else { + return TC_ACT_OK; + } + + tkey.tunnel_id = 10000; + tkey.tunnel_ttl = 64; + /* 2401:db02:0:0:0:0:0:66 */ + tkey.remote_ipv6[0] = _htonl(0x2401db02); + tkey.remote_ipv6[1] = 0; + tkey.remote_ipv6[2] = 0; + tkey.remote_ipv6[3] = _htonl(0x00000066); + bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), BPF_F_TUNINFO_IPV6); + return bpf_redirect(*ifindex, 0); +} + +SEC("drop_non_tun_vip") +int _drop_non_tun_vip(struct __sk_buff *skb) +{ + struct bpf_tunnel_key tkey = {}; + void *data = (void *)(long)skb->data; + struct eth_hdr *eth = data; + void *data_end = (void *)(long)skb->data_end; + + if (data + sizeof(*eth) > data_end) + return TC_ACT_OK; + + if (eth->h_proto == htons(ETH_P_IP)) { + struct iphdr *iph = data + sizeof(*eth); + + if (data + sizeof(*eth) + sizeof(*iph) > data_end) + return TC_ACT_OK; + + if (is_vip_addr(eth->h_proto, iph->daddr)) + return TC_ACT_SHOT; + } else if (eth->h_proto == htons(ETH_P_IPV6)) { + struct ipv6hdr *ip6h = data + sizeof(*eth); + + if (data + sizeof(*eth) + sizeof(*ip6h) > data_end) + return TC_ACT_OK; + + if (is_vip_addr(eth->h_proto, ip6h->daddr.s6_addr32[0])) + return TC_ACT_SHOT; + } + + return TC_ACT_OK; +} + +char _license[] SEC("license") = "GPL"; diff --git a/samples/bpf/tc_l2_redirect_user.c b/samples/bpf/tc_l2_redirect_user.c new file mode 100644 index 000000000000..4013c5337b91 --- /dev/null +++ b/samples/bpf/tc_l2_redirect_user.c @@ -0,0 +1,73 @@ +/* Copyright (c) 2016 Facebook + * + * 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 "libbpf.h" + +static void usage(void) +{ + printf("Usage: tc_l2_ipip_redirect [...]\n"); + printf(" -U Update an already pinned BPF array\n"); + printf(" -i Interface index\n"); + printf(" -h Display this help\n"); +} + +int main(int argc, char **argv) +{ + const char *pinned_file = NULL; + int ifindex = -1; + int array_key = 0; + int array_fd = -1; + int ret = -1; + int opt; + + while ((opt = getopt(argc, argv, "F:U:i:")) != -1) { + switch (opt) { + /* General args */ + case 'U': + pinned_file = optarg; + break; + case 'i': + ifindex = atoi(optarg); + break; + default: + usage(); + goto out; + } + } + + if (ifindex < 0 || !pinned_file) { + usage(); + goto out; + } + + array_fd = bpf_obj_get(pinned_file); + if (array_fd < 0) { + fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n", + pinned_file, strerror(errno), errno); + goto out; + } + + /* bpf_tunnel_key.remote_ipv4 expects host byte orders */ + ret = bpf_update_elem(array_fd, &array_key, &ifindex, 0); + if (ret) { + perror("bpf_update_elem"); + goto out; + } + +out: + if (array_fd != -1) + close(array_fd); + return ret; +}