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authorToke Høiland-Jørgensen <toke@redhat.com>2020-10-20 23:25:56 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2020-10-22 01:28:54 +0200
commitba452c9e996d8a4c347b32805f91abb70de5de7e (patch)
tree7cc639674290dda9b607ed44dc572b30f55502a7 /net
parentc5eb48e89286510d638844104a6f6582a4838a32 (diff)
downloadlinux-stericsson-ba452c9e996d8a4c347b32805f91abb70de5de7e.tar.gz
bpf: Fix bpf_redirect_neigh helper api to support supplying nexthop
Based on the discussion in [0], update the bpf_redirect_neigh() helper to accept an optional parameter specifying the nexthop information. This makes it possible to combine bpf_fib_lookup() and bpf_redirect_neigh() without incurring a duplicate FIB lookup - since the FIB lookup helper will return the nexthop information even if no neighbour is present, this can simply be passed on to bpf_redirect_neigh() if bpf_fib_lookup() returns BPF_FIB_LKUP_RET_NO_NEIGH. Thus fix & extend it before helper API is frozen. [0] https://lore.kernel.org/bpf/393e17fc-d187-3a8d-2f0d-a627c7c63fca@iogearbox.net/ Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/bpf/160322915615.32199.1187570224032024535.stgit@toke.dk
Diffstat (limited to 'net')
-rw-r--r--net/core/filter.c158
1 files changed, 99 insertions, 59 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index c5e2a1c5fd8d..6d0fa65a4a46 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2165,12 +2165,12 @@ static int __bpf_redirect(struct sk_buff *skb, struct net_device *dev,
}
#if IS_ENABLED(CONFIG_IPV6)
-static int bpf_out_neigh_v6(struct net *net, struct sk_buff *skb)
+static int bpf_out_neigh_v6(struct net *net, struct sk_buff *skb,
+ struct net_device *dev, struct bpf_nh_params *nh)
{
- 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 dst_entry *dst = NULL;
struct neighbour *neigh;
if (dev_xmit_recursion()) {
@@ -2196,8 +2196,13 @@ static int bpf_out_neigh_v6(struct net *net, struct sk_buff *skb)
}
rcu_read_lock_bh();
- nexthop = rt6_nexthop(container_of(dst, struct rt6_info, dst),
- &ipv6_hdr(skb)->daddr);
+ if (!nh) {
+ dst = skb_dst(skb);
+ nexthop = rt6_nexthop(container_of(dst, struct rt6_info, dst),
+ &ipv6_hdr(skb)->daddr);
+ } else {
+ nexthop = &nh->ipv6_nh;
+ }
neigh = ip_neigh_gw6(dev, nexthop);
if (likely(!IS_ERR(neigh))) {
int ret;
@@ -2210,36 +2215,43 @@ static int bpf_out_neigh_v6(struct net *net, struct sk_buff *skb)
return ret;
}
rcu_read_unlock_bh();
- IP6_INC_STATS(dev_net(dst->dev),
- ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
+ if (dst)
+ 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)
+static int __bpf_redirect_neigh_v6(struct sk_buff *skb, struct net_device *dev,
+ struct bpf_nh_params *nh)
{
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;
+ if (!nh) {
+ 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);
+ skb_dst_set(skb, dst);
+ } else if (nh->nh_family != AF_INET6) {
+ goto out_drop;
+ }
- err = bpf_out_neigh_v6(net, skb);
+ err = bpf_out_neigh_v6(net, skb, dev, nh);
if (unlikely(net_xmit_eval(err)))
dev->stats.tx_errors++;
else
@@ -2252,7 +2264,8 @@ out_xmit:
return ret;
}
#else
-static int __bpf_redirect_neigh_v6(struct sk_buff *skb, struct net_device *dev)
+static int __bpf_redirect_neigh_v6(struct sk_buff *skb, struct net_device *dev,
+ struct bpf_nh_params *nh)
{
kfree_skb(skb);
return NET_XMIT_DROP;
@@ -2260,11 +2273,9 @@ static int __bpf_redirect_neigh_v6(struct sk_buff *skb, struct net_device *dev)
#endif /* CONFIG_IPV6 */
#if IS_ENABLED(CONFIG_INET)
-static int bpf_out_neigh_v4(struct net *net, struct sk_buff *skb)
+static int bpf_out_neigh_v4(struct net *net, struct sk_buff *skb,
+ struct net_device *dev, struct bpf_nh_params *nh)
{
- 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;
@@ -2292,7 +2303,21 @@ static int bpf_out_neigh_v4(struct net *net, struct sk_buff *skb)
}
rcu_read_lock_bh();
- neigh = ip_neigh_for_gw(rt, skb, &is_v6gw);
+ if (!nh) {
+ struct dst_entry *dst = skb_dst(skb);
+ struct rtable *rt = container_of(dst, struct rtable, dst);
+
+ neigh = ip_neigh_for_gw(rt, skb, &is_v6gw);
+ } else if (nh->nh_family == AF_INET6) {
+ neigh = ip_neigh_gw6(dev, &nh->ipv6_nh);
+ is_v6gw = true;
+ } else if (nh->nh_family == AF_INET) {
+ neigh = ip_neigh_gw4(dev, nh->ipv4_nh);
+ } else {
+ rcu_read_unlock_bh();
+ goto out_drop;
+ }
+
if (likely(!IS_ERR(neigh))) {
int ret;
@@ -2309,33 +2334,37 @@ out_drop:
return -ENETDOWN;
}
-static int __bpf_redirect_neigh_v4(struct sk_buff *skb, struct net_device *dev)
+static int __bpf_redirect_neigh_v4(struct sk_buff *skb, struct net_device *dev,
+ struct bpf_nh_params *nh)
{
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;
- }
+ if (!nh) {
+ 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,
+ };
+ struct rtable *rt;
+
+ 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);
+ skb_dst_set(skb, &rt->dst);
+ }
- err = bpf_out_neigh_v4(net, skb);
+ err = bpf_out_neigh_v4(net, skb, dev, nh);
if (unlikely(net_xmit_eval(err)))
dev->stats.tx_errors++;
else
@@ -2348,14 +2377,16 @@ out_xmit:
return ret;
}
#else
-static int __bpf_redirect_neigh_v4(struct sk_buff *skb, struct net_device *dev)
+static int __bpf_redirect_neigh_v4(struct sk_buff *skb, struct net_device *dev,
+ struct bpf_nh_params *nh)
{
kfree_skb(skb);
return NET_XMIT_DROP;
}
#endif /* CONFIG_INET */
-static int __bpf_redirect_neigh(struct sk_buff *skb, struct net_device *dev)
+static int __bpf_redirect_neigh(struct sk_buff *skb, struct net_device *dev,
+ struct bpf_nh_params *nh)
{
struct ethhdr *ethh = eth_hdr(skb);
@@ -2370,9 +2401,9 @@ static int __bpf_redirect_neigh(struct sk_buff *skb, struct net_device *dev)
skb_reset_network_header(skb);
if (skb->protocol == htons(ETH_P_IP))
- return __bpf_redirect_neigh_v4(skb, dev);
+ return __bpf_redirect_neigh_v4(skb, dev, nh);
else if (skb->protocol == htons(ETH_P_IPV6))
- return __bpf_redirect_neigh_v6(skb, dev);
+ return __bpf_redirect_neigh_v6(skb, dev, nh);
out:
kfree_skb(skb);
return -ENOTSUPP;
@@ -2382,7 +2413,8 @@ out:
enum {
BPF_F_NEIGH = (1ULL << 1),
BPF_F_PEER = (1ULL << 2),
-#define BPF_F_REDIRECT_INTERNAL (BPF_F_NEIGH | BPF_F_PEER)
+ BPF_F_NEXTHOP = (1ULL << 3),
+#define BPF_F_REDIRECT_INTERNAL (BPF_F_NEIGH | BPF_F_PEER | BPF_F_NEXTHOP)
};
BPF_CALL_3(bpf_clone_redirect, struct sk_buff *, skb, u32, ifindex, u64, flags)
@@ -2455,7 +2487,8 @@ int skb_do_redirect(struct sk_buff *skb)
return -EAGAIN;
}
return flags & BPF_F_NEIGH ?
- __bpf_redirect_neigh(skb, dev) :
+ __bpf_redirect_neigh(skb, dev, flags & BPF_F_NEXTHOP ?
+ &ri->nh : NULL) :
__bpf_redirect(skb, dev, flags);
out_drop:
kfree_skb(skb);
@@ -2504,16 +2537,21 @@ static const struct bpf_func_proto bpf_redirect_peer_proto = {
.arg2_type = ARG_ANYTHING,
};
-BPF_CALL_2(bpf_redirect_neigh, u32, ifindex, u64, flags)
+BPF_CALL_4(bpf_redirect_neigh, u32, ifindex, struct bpf_redir_neigh *, params,
+ int, plen, u64, flags)
{
struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
- if (unlikely(flags))
+ if (unlikely((plen && plen < sizeof(*params)) || flags))
return TC_ACT_SHOT;
- ri->flags = BPF_F_NEIGH;
+ ri->flags = BPF_F_NEIGH | (plen ? BPF_F_NEXTHOP : 0);
ri->tgt_index = ifindex;
+ BUILD_BUG_ON(sizeof(struct bpf_redir_neigh) != sizeof(struct bpf_nh_params));
+ if (plen)
+ memcpy(&ri->nh, params, sizeof(ri->nh));
+
return TC_ACT_REDIRECT;
}
@@ -2522,7 +2560,9 @@ static const struct bpf_func_proto bpf_redirect_neigh_proto = {
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_ANYTHING,
- .arg2_type = ARG_ANYTHING,
+ .arg2_type = ARG_PTR_TO_MEM_OR_NULL,
+ .arg3_type = ARG_CONST_SIZE_OR_ZERO,
+ .arg4_type = ARG_ANYTHING,
};
BPF_CALL_2(bpf_msg_apply_bytes, struct sk_msg *, msg, u32, bytes)