Commit 97f91a7c authored by John Fastabend's avatar John Fastabend Committed by David S. Miller

bpf: add bpf_redirect_map helper routine

BPF programs can use the devmap with a bpf_redirect_map() helper
routine to forward packets to netdevice in map.
Signed-off-by: default avatarJohn Fastabend <[email protected]>
Signed-off-by: default avatarJesper Dangaard Brouer <[email protected]>
Acked-by: default avatarDaniel Borkmann <[email protected]>
Signed-off-by: default avatarDavid S. Miller <[email protected]>
parent 546ac1ff
......@@ -379,4 +379,7 @@ extern const struct bpf_func_proto bpf_get_stackid_proto;
void bpf_user_rnd_init_once(void);
u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
/* Map specifics */
struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key);
#endif /* _LINUX_BPF_H */
......@@ -348,6 +348,11 @@ union bpf_attr {
* @flags: bit 0 - if set, redirect to ingress instead of egress
* other bits - reserved
* Return: TC_ACT_REDIRECT
* int bpf_redirect_map(key, map, flags)
* redirect to endpoint in map
* @key: index in map to lookup
* @map: fd of map to do lookup in
* @flags: --
*
* u32 bpf_get_route_realm(skb)
* retrieve a dst's tclassid
......@@ -592,7 +597,8 @@ union bpf_attr {
FN(get_socket_uid), \
FN(set_hash), \
FN(setsockopt), \
FN(skb_adjust_room),
FN(skb_adjust_room), \
FN(redirect_map),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
......
......@@ -159,6 +159,18 @@ static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
return 0;
}
struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key)
{
struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
struct bpf_dtab_netdev *dev;
if (key >= map->max_entries)
return NULL;
dev = READ_ONCE(dtab->netdev_map[key]);
return dev ? dev->dev : NULL;
}
/* rcu_read_lock (from syscall and BPF contexts) ensures that if a delete and/or
* update happens in parallel here a dev_put wont happen until after reading the
* ifindex.
......
......@@ -1312,6 +1312,10 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id)
if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY)
goto error;
break;
case BPF_FUNC_redirect_map:
if (map->map_type != BPF_MAP_TYPE_DEVMAP)
goto error;
break;
default:
break;
}
......
......@@ -1779,6 +1779,7 @@ static const struct bpf_func_proto bpf_clone_redirect_proto = {
struct redirect_info {
u32 ifindex;
u32 flags;
struct bpf_map *map;
};
static DEFINE_PER_CPU(struct redirect_info, redirect_info);
......@@ -1792,6 +1793,7 @@ BPF_CALL_2(bpf_redirect, u32, ifindex, u64, flags)
ri->ifindex = ifindex;
ri->flags = flags;
ri->map = NULL;
return TC_ACT_REDIRECT;
}
......@@ -1819,6 +1821,29 @@ static const struct bpf_func_proto bpf_redirect_proto = {
.arg2_type = ARG_ANYTHING,
};
BPF_CALL_3(bpf_redirect_map, struct bpf_map *, map, u32, ifindex, u64, flags)
{
struct redirect_info *ri = this_cpu_ptr(&redirect_info);
if (unlikely(flags))
return XDP_ABORTED;
ri->ifindex = ifindex;
ri->flags = flags;
ri->map = map;
return XDP_REDIRECT;
}
static const struct bpf_func_proto bpf_redirect_map_proto = {
.func = bpf_redirect_map,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_ANYTHING,
.arg3_type = ARG_ANYTHING,
};
BPF_CALL_1(bpf_get_cgroup_classid, const struct sk_buff *, skb)
{
return task_get_classid(skb);
......@@ -2423,14 +2448,39 @@ static int __bpf_tx_xdp(struct net_device *dev, struct xdp_buff *xdp)
return -EOPNOTSUPP;
}
int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp,
struct bpf_prog *xdp_prog)
{
struct redirect_info *ri = this_cpu_ptr(&redirect_info);
struct bpf_map *map = ri->map;
struct net_device *fwd;
int err = -EINVAL;
ri->ifindex = 0;
ri->map = NULL;
fwd = __dev_map_lookup_elem(map, ri->ifindex);
if (!fwd)
goto out;
trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT);
err = __bpf_tx_xdp(fwd, xdp);
out:
return err;
}
int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
struct bpf_prog *xdp_prog)
{
struct redirect_info *ri = this_cpu_ptr(&redirect_info);
struct net_device *fwd;
if (ri->map)
return xdp_do_redirect_map(dev, xdp, xdp_prog);
fwd = dev_get_by_index_rcu(dev_net(dev), ri->ifindex);
ri->ifindex = 0;
ri->map = NULL;
if (unlikely(!fwd)) {
bpf_warn_invalid_xdp_redirect(ri->ifindex);
return -EINVAL;
......@@ -3089,6 +3139,8 @@ xdp_func_proto(enum bpf_func_id func_id)
return &bpf_xdp_adjust_head_proto;
case BPF_FUNC_redirect:
return &bpf_xdp_redirect_proto;
case BPF_FUNC_redirect_map:
return &bpf_redirect_map_proto;
default:
return bpf_base_func_proto(func_id);
}
......
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