On 2/11/19 5:42 PM, Peter Oskolkov wrote:
> @@ -88,6 +90,35 @@ static int run_lwt_bpf(struct sk_buff *skb, struct
> bpf_lwt_prog *lwt,
> return ret;
> }
>
> +static int bpf_lwt_input_reroute(struct sk_buff *skb)
> +{
> + int err = -EINVAL;
> +
> + if (skb->protocol == htons(ETH_P_IP)) {
> + struct iphdr *iph = ip_hdr(skb);
> +
> + err = ip_route_input_noref(skb, iph->daddr, iph->saddr,
> + iph->tos, skb_dst(skb)->dev);
> + } else if (skb->protocol == htons(ETH_P_IPV6)) {
> +#if IS_ENABLED(CONFIG_IPV6)
> + err = ipv6_stub->ipv6_route_input(skb);
> +#else
> + pr_warn_once("BPF_LWT_REROUTE input: IPV6 not available\n");
> +#endif
The stub defines ipv6_route_input when IPv6 is not enabled.
addrconf_core.o is compiled in if NET is enabled irregardless of
CONFIG_IPV6. ie., you don't need the IS_ENABLED check here.
If a bpf program pushes a v6 header the stub returns -EAFNOSUPPORT based
on patch 4.
> + } else {
> + pr_warn_once("BPF_LWT_REROUTE input: unsupported proto %d\n",
> + skb->protocol);
You don't need a warn on here; just return -EAFNOSUPPORT.
> + }
> +
> + if (err)
> + goto err;
> + return dst_input(skb);
> +
> +err:
> + kfree_skb(skb);
> + return err;
> +}
> +
> static int bpf_input(struct sk_buff *skb)
> {
> struct dst_entry *dst = skb_dst(skb);
> @@ -99,6 +130,8 @@ static int bpf_input(struct sk_buff *skb)
> ret = run_lwt_bpf(skb, &bpf->in, dst, NO_REDIRECT);
> if (ret < 0)
> return ret;
> + if (ret == BPF_LWT_REROUTE)
> + return bpf_lwt_input_reroute(skb);
> }
>
> if (unlikely(!dst->lwtstate->orig_input)) {
> @@ -148,6 +181,95 @@ static int xmit_check_hhlen(struct sk_buff *skb)
> return 0;
> }
>
> +static int bpf_lwt_xmit_reroute(struct sk_buff *skb)
> +{
> + struct net_device *l3mdev = l3mdev_master_dev_rcu(skb_dst(skb)->dev);
> + int oif = l3mdev ? l3mdev->ifindex : 0;
> + struct dst_entry *dst = NULL;
> + struct sock *sk;
> + struct net *net;
> + bool ipv4;
> + int err;
> +
> + if (skb->protocol == htons(ETH_P_IP)) {
> + ipv4 = true;
> + } else if (skb->protocol == htons(ETH_P_IPV6)) {
> + ipv4 = false;
> + } else {
> + pr_warn_once("BPF_LWT_REROUTE xmit: unsupported proto %d\n",
> + skb->protocol);
same here - no warn on.
> + return -EINVAL;
> + }
> +
> + sk = sk_to_full_sk(skb->sk);
> + if (sk) {
> + if (sk->sk_bound_dev_if)
> + oif = sk->sk_bound_dev_if;
> + net = sock_net(sk);
> + } else {
> + net = dev_net(skb_dst(skb)->dev);
> + }
> +
> + if (ipv4) {
> + struct iphdr *iph = ip_hdr(skb);
> + struct flowi4 fl4 = {};
> + struct rtable *rt;
> +
> + fl4.flowi4_oif = oif;
> + fl4.flowi4_mark = skb->mark;
> + fl4.flowi4_uid = sock_net_uid(net, sk);
> + fl4.flowi4_tos = RT_TOS(iph->tos);
> + fl4.flowi4_flags = FLOWI_FLAG_ANYSRC;
> + fl4.flowi4_proto = iph->protocol;
> + fl4.daddr = iph->daddr;
> + fl4.saddr = iph->saddr;
> +
> + rt = ip_route_output_key(net, &fl4);
> + if (IS_ERR(rt) || rt->dst.error)
> + return -EINVAL;
> + dst = &rt->dst;
> + } else {
> +#if IS_ENABLED(CONFIG_IPV6)
> + struct ipv6hdr *iph6 = ipv6_hdr(skb);
> + struct flowi6 fl6 = {};
> +
> + fl6.flowi6_oif = oif;
> + fl6.flowi6_mark = skb->mark;
> + fl6.flowi6_uid = sock_net_uid(net, sk);
> + fl6.flowlabel = ip6_flowinfo(iph6);
> + fl6.flowi6_proto = iph6->nexthdr;
> + fl6.daddr = iph6->daddr;
> + fl6.saddr = iph6->saddr;
> +
> + err = ipv6_stub->ipv6_dst_lookup(net, skb->sk, &dst, &fl6);
> + if (err || IS_ERR(dst) || dst->error)
> + return -EINVAL;
> +#else
> + pr_warn_once("BPF_LWT_REROUTE xmit: IPV6 not available\n");
> + return -EINVAL;
> +#endif
No #if .. #endif needed. The stub handles it.
