diff options
| -rw-r--r-- | include/linux/skbuff.h | 5 | ||||
| -rw-r--r-- | include/uapi/linux/bpf.h | 14 | ||||
| -rw-r--r-- | net/core/filter.c | 276 | ||||
| -rw-r--r-- | tools/include/uapi/linux/bpf.h | 14 |
4 files changed, 294 insertions, 15 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 04a18e01b362..3d0cf3722bb4 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2548,6 +2548,11 @@ static inline int skb_mac_header_was_set(const struct sk_buff *skb) return skb->mac_header != (typeof(skb->mac_header))~0U; } +static inline void skb_unset_mac_header(struct sk_buff *skb) +{ + skb->mac_header = (typeof(skb->mac_header))~0U; +} + static inline void skb_reset_mac_header(struct sk_buff *skb) { skb->mac_header = skb->data - skb->head; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 6116a7f54c8f..1f17c6752deb 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3652,6 +3652,19 @@ union bpf_attr { * associated socket instead of the current process. * Return * The id is returned or 0 in case the id could not be retrieved. + * + * long bpf_redirect_neigh(u32 ifindex, u64 flags) + * Description + * Redirect the packet to another net device of index *ifindex* + * and fill in L2 addresses from neighboring subsystem. This helper + * is somewhat similar to **bpf_redirect**\ (), except that it + * fills in e.g. MAC addresses based on the L3 information from + * the packet. This helper is supported for IPv4 and IPv6 protocols. + * The *flags* argument is reserved and must be 0. The helper is + * currently only supported for tc BPF program types. + * Return + * The helper returns **TC_ACT_REDIRECT** on success or + * **TC_ACT_SHOT** on error. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3806,6 +3819,7 @@ union bpf_attr { FN(snprintf_btf), \ FN(seq_printf_btf), \ FN(skb_cgroup_classid), \ + FN(redirect_neigh), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/net/core/filter.c b/net/core/filter.c index a0776e48dcc9..3fb6adad1957 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2163,13 +2163,233 @@ static int __bpf_redirect(struct sk_buff *skb, struct net_device *dev, return __bpf_redirect_no_mac(skb, dev, flags); } +#if IS_ENABLED(CONFIG_IPV6) +static int bpf_out_neigh_v6(struct net *net, struct sk_buff *skb) +{ + struct dst_entry *dst = skb_dst(skb); + struct net_device *dev = dst->dev; + u32 hh_len = LL_RESERVED_SPACE(dev); + const struct in6_addr *nexthop; + struct neighbour *neigh; + + if (dev_xmit_recursion()) { + net_crit_ratelimited("bpf: recursion limit reached on datapath, buggy bpf program?\n"); + goto out_drop; + } + + skb->dev = dev; + skb->tstamp = 0; + + if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { + struct sk_buff *skb2; + + skb2 = skb_realloc_headroom(skb, hh_len); + if (unlikely(!skb2)) { + kfree_skb(skb); + return -ENOMEM; + } + if (skb->sk) + skb_set_owner_w(skb2, skb->sk); + consume_skb(skb); + skb = skb2; + } + + rcu_read_lock_bh(); + nexthop = rt6_nexthop(container_of(dst, struct rt6_info, dst), + &ipv6_hdr(skb)->daddr); + neigh = ip_neigh_gw6(dev, nexthop); + if (likely(!IS_ERR(neigh))) { + int ret; + + sock_confirm_neigh(skb, neigh); + dev_xmit_recursion_inc(); + ret = neigh_output(neigh, skb, false); + dev_xmit_recursion_dec(); + rcu_read_unlock_bh(); + return ret; + } + rcu_read_unlock_bh(); + IP6_INC_STATS(dev_net(dst->dev), + ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); +out_drop: + kfree_skb(skb); + return -ENETDOWN; +} + +static int __bpf_redirect_neigh_v6(struct sk_buff *skb, struct net_device *dev) +{ + const struct ipv6hdr *ip6h = ipv6_hdr(skb); + struct net *net = dev_net(dev); + int err, ret = NET_XMIT_DROP; + struct dst_entry *dst; + struct flowi6 fl6 = { + .flowi6_flags = FLOWI_FLAG_ANYSRC, + .flowi6_mark = skb->mark, + .flowlabel = ip6_flowinfo(ip6h), + .flowi6_oif = dev->ifindex, + .flowi6_proto = ip6h->nexthdr, + .daddr = ip6h->daddr, + .saddr = ip6h->saddr, + }; + + dst = ipv6_stub->ipv6_dst_lookup_flow(net, NULL, &fl6, NULL); + if (IS_ERR(dst)) + goto out_drop; + + skb_dst_set(skb, dst); + + err = bpf_out_neigh_v6(net, skb); + if (unlikely(net_xmit_eval(err))) + dev->stats.tx_errors++; + else + ret = NET_XMIT_SUCCESS; + goto out_xmit; +out_drop: + dev->stats.tx_errors++; + kfree_skb(skb); +out_xmit: + return ret; +} +#else +static int __bpf_redirect_neigh_v6(struct sk_buff *skb, struct net_device *dev) +{ + kfree_skb(skb); + return NET_XMIT_DROP; +} +#endif /* CONFIG_IPV6 */ + +#if IS_ENABLED(CONFIG_INET) +static int bpf_out_neigh_v4(struct net *net, struct sk_buff *skb) +{ + struct dst_entry *dst = skb_dst(skb); + struct rtable *rt = container_of(dst, struct rtable, dst); + struct net_device *dev = dst->dev; + u32 hh_len = LL_RESERVED_SPACE(dev); + struct neighbour *neigh; + bool is_v6gw = false; + + if (dev_xmit_recursion()) { + net_crit_ratelimited("bpf: recursion limit reached on datapath, buggy bpf program?\n"); + goto out_drop; + } + + skb->dev = dev; + skb->tstamp = 0; + + if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { + struct sk_buff *skb2; + + skb2 = skb_realloc_headroom(skb, hh_len); + if (unlikely(!skb2)) { + kfree_skb(skb); + return -ENOMEM; + } + if (skb->sk) + skb_set_owner_w(skb2, skb->sk); + consume_skb(skb); + skb = skb2; + } + + rcu_read_lock_bh(); + neigh = ip_neigh_for_gw(rt, skb, &is_v6gw); + if (likely(!IS_ERR(neigh))) { + int ret; + + sock_confirm_neigh(skb, neigh); + dev_xmit_recursion_inc(); + ret = neigh_output(neigh, skb, is_v6gw); + dev_xmit_recursion_dec(); + rcu_read_unlock_bh(); + return ret; + } + rcu_read_unlock_bh(); +out_drop: + kfree_skb(skb); + return -ENETDOWN; +} + +static int __bpf_redirect_neigh_v4(struct sk_buff *skb, struct net_device *dev) +{ + const struct iphdr *ip4h = ip_hdr(skb); + struct net *net = dev_net(dev); + int err, ret = NET_XMIT_DROP; + struct rtable *rt; + struct flowi4 fl4 = { + .flowi4_flags = FLOWI_FLAG_ANYSRC, + .flowi4_mark = skb->mark, + .flowi4_tos = RT_TOS(ip4h->tos), + .flowi4_oif = dev->ifindex, + .flowi4_proto = ip4h->protocol, + .daddr = ip4h->daddr, + .saddr = ip4h->saddr, + }; + + rt = ip_route_output_flow(net, &fl4, NULL); + if (IS_ERR(rt)) + goto out_drop; + if (rt->rt_type != RTN_UNICAST && rt->rt_type != RTN_LOCAL) { + ip_rt_put(rt); + goto out_drop; + } + + skb_dst_set(skb, &rt->dst); + + err = bpf_out_neigh_v4(net, skb); + if (unlikely(net_xmit_eval(err))) + dev->stats.tx_errors++; + else + ret = NET_XMIT_SUCCESS; + goto out_xmit; +out_drop: + dev->stats.tx_errors++; + kfree_skb(skb); +out_xmit: + return ret; +} +#else +static int __bpf_redirect_neigh_v4(struct sk_buff *skb, struct net_device *dev) +{ + kfree_skb(skb); + return NET_XMIT_DROP; +} +#endif /* CONFIG_INET */ + +static int __bpf_redirect_neigh(struct sk_buff *skb, struct net_device *dev) +{ + struct ethhdr *ethh = eth_hdr(skb); + + if (unlikely(skb->mac_header >= skb->network_header)) + goto out; + bpf_push_mac_rcsum(skb); + if (is_multicast_ether_addr(ethh->h_dest)) + goto out; + + skb_pull(skb, sizeof(*ethh)); + skb_unset_mac_header(skb); + skb_reset_network_header(skb); + + if (skb->protocol == htons(ETH_P_IP)) + return __bpf_redirect_neigh_v4(skb, dev); + else if (skb->protocol == htons(ETH_P_IPV6)) + return __bpf_redirect_neigh_v6(skb, dev); +out: + kfree_skb(skb); + return -ENOTSUPP; +} + +/* Internal, non-exposed redirect flags. */ +enum { + BPF_F_NEIGH = (1ULL << 1), +#define BPF_F_REDIRECT_INTERNAL (BPF_F_NEIGH) +}; + BPF_CALL_3(bpf_clone_redirect, struct sk_buff *, skb, u32, ifindex, u64, flags) { struct net_device *dev; struct sk_buff *clone; int ret; - if (unlikely(flags & ~(BPF_F_INGRESS))) + if (unlikely(flags & (~(BPF_F_INGRESS) | BPF_F_REDIRECT_INTERNAL))) return -EINVAL; dev = dev_get_by_index_rcu(dev_net(skb->dev), ifindex); @@ -2206,23 +2426,11 @@ static const struct bpf_func_proto bpf_clone_redirect_proto = { DEFINE_PER_CPU(struct bpf_redirect_info, bpf_redirect_info); EXPORT_PER_CPU_SYMBOL_GPL(bpf_redirect_info); -BPF_CALL_2(bpf_redirect, u32, ifindex, u64, flags) -{ - struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info); - - if (unlikely(flags & ~(BPF_F_INGRESS))) - return TC_ACT_SHOT; - - ri->flags = flags; - ri->tgt_index = ifindex; - - return TC_ACT_REDIRECT; -} - int skb_do_redirect(struct sk_buff *skb) { struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info); struct net_device *dev; + u32 flags = ri->flags; dev = dev_get_by_index_rcu(dev_net(skb->dev), ri->tgt_index); ri->tgt_index = 0; @@ -2231,7 +2439,22 @@ int skb_do_redirect(struct sk_buff *skb) return -EINVAL; } - return __bpf_redirect(skb, dev, ri->flags); + return flags & BPF_F_NEIGH ? + __bpf_redirect_neigh(skb, dev) : + __bpf_redirect(skb, dev, flags); +} + +BPF_CALL_2(bpf_redirect, u32, ifindex, u64, flags) +{ + struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info); + + if (unlikely(flags & (~(BPF_F_INGRESS) | BPF_F_REDIRECT_INTERNAL))) + return TC_ACT_SHOT; + + ri->flags = flags; + ri->tgt_index = ifindex; + + return TC_ACT_REDIRECT; } static const struct bpf_func_proto bpf_redirect_proto = { @@ -2242,6 +2465,27 @@ static const struct bpf_func_proto bpf_redirect_proto = { .arg2_type = ARG_ANYTHING, }; +BPF_CALL_2(bpf_redirect_neigh, u32, ifindex, u64, flags) +{ + struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info); + + if (unlikely(flags)) + return TC_ACT_SHOT; + + ri->flags = BPF_F_NEIGH; + ri->tgt_index = ifindex; + + return TC_ACT_REDIRECT; +} + +static const struct bpf_func_proto bpf_redirect_neigh_proto = { + .func = bpf_redirect_neigh, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_ANYTHING, + .arg2_type = ARG_ANYTHING, +}; + BPF_CALL_2(bpf_msg_apply_bytes, struct sk_msg *, msg, u32, bytes) { msg->apply_bytes = bytes; @@ -6759,6 +7003,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return bpf_get_skb_set_tunnel_proto(func_id); case BPF_FUNC_redirect: return &bpf_redirect_proto; + case BPF_FUNC_redirect_neigh: + return &bpf_redirect_neigh_proto; case BPF_FUNC_get_route_realm: return &bpf_get_route_realm_proto; case BPF_FUNC_get_hash_recalc: diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 6116a7f54c8f..1f17c6752deb 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3652,6 +3652,19 @@ union bpf_attr { * associated socket instead of the current process. * Return * The id is returned or 0 in case the id could not be retrieved. + * + * long bpf_redirect_neigh(u32 ifindex, u64 flags) + * Description + * Redirect the packet to another net device of index *ifindex* + * and fill in L2 addresses from neighboring subsystem. This helper + * is somewhat similar to **bpf_redirect**\ (), except that it + * fills in e.g. MAC addresses based on the L3 information from + * the packet. This helper is supported for IPv4 and IPv6 protocols. + * The *flags* argument is reserved and must be 0. The helper is + * currently only supported for tc BPF program types. + * Return + * The helper returns **TC_ACT_REDIRECT** on success or + * **TC_ACT_SHOT** on error. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3806,6 +3819,7 @@ union bpf_attr { FN(snprintf_btf), \ FN(seq_printf_btf), \ FN(skb_cgroup_classid), \ + FN(redirect_neigh), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper |