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xdp: Move conversion to xdp_frame out of map functions
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All map redirect functions except XSK maps convert xdp_buff to xdp_frame
before enqueueing it. So move this conversion of out the map functions
and into xdp_do_redirect(). This removes a bit of duplicated code, but more
importantly it makes it possible to support caller-allocated xdp_frame
structures, which will be added in a subsequent commit.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220103150812.87914-5-toke@redhat.com
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Toke Høiland-Jørgensen authored and Alexei Starovoitov committed Jan 6, 2022
1 parent 64693ec commit d53ad5d
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Showing 4 changed files with 39 additions and 45 deletions.
20 changes: 10 additions & 10 deletions include/linux/bpf.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1669,17 +1669,17 @@ void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth);
struct btf *bpf_get_btf_vmlinux(void);

/* Map specifics */
struct xdp_buff;
struct xdp_frame;
struct sk_buff;
struct bpf_dtab_netdev;
struct bpf_cpu_map_entry;

void __dev_flush(void);
int dev_xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp,
int dev_xdp_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
struct net_device *dev_rx);
int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,
int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_frame *xdpf,
struct net_device *dev_rx);
int dev_map_enqueue_multi(struct xdp_buff *xdp, struct net_device *dev_rx,
int dev_map_enqueue_multi(struct xdp_frame *xdpf, struct net_device *dev_rx,
struct bpf_map *map, bool exclude_ingress);
int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
struct bpf_prog *xdp_prog);
Expand All @@ -1688,7 +1688,7 @@ int dev_map_redirect_multi(struct net_device *dev, struct sk_buff *skb,
bool exclude_ingress);

void __cpu_map_flush(void);
int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_buff *xdp,
int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf,
struct net_device *dev_rx);
int cpu_map_generic_redirect(struct bpf_cpu_map_entry *rcpu,
struct sk_buff *skb);
Expand Down Expand Up @@ -1866,26 +1866,26 @@ static inline void __dev_flush(void)
{
}

struct xdp_buff;
struct xdp_frame;
struct bpf_dtab_netdev;
struct bpf_cpu_map_entry;

static inline
int dev_xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp,
int dev_xdp_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
struct net_device *dev_rx)
{
return 0;
}

static inline
int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,
int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_frame *xdpf,
struct net_device *dev_rx)
{
return 0;
}

static inline
int dev_map_enqueue_multi(struct xdp_buff *xdp, struct net_device *dev_rx,
int dev_map_enqueue_multi(struct xdp_frame *xdpf, struct net_device *dev_rx,
struct bpf_map *map, bool exclude_ingress)
{
return 0;
Expand Down Expand Up @@ -1913,7 +1913,7 @@ static inline void __cpu_map_flush(void)
}

static inline int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu,
struct xdp_buff *xdp,
struct xdp_frame *xdpf,
struct net_device *dev_rx)
{
return 0;
Expand Down
8 changes: 1 addition & 7 deletions kernel/bpf/cpumap.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -746,15 +746,9 @@ static void bq_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf)
list_add(&bq->flush_node, flush_list);
}

int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_buff *xdp,
int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf,
struct net_device *dev_rx)
{
struct xdp_frame *xdpf;

xdpf = xdp_convert_buff_to_frame(xdp);
if (unlikely(!xdpf))
return -EOVERFLOW;

/* Info needed when constructing SKB on remote CPU */
xdpf->dev_rx = dev_rx;

Expand Down
32 changes: 11 additions & 21 deletions kernel/bpf/devmap.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -467,24 +467,19 @@ static void bq_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
bq->q[bq->count++] = xdpf;
}

static inline int __xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp,
static inline int __xdp_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
struct net_device *dev_rx,
struct bpf_prog *xdp_prog)
{
struct xdp_frame *xdpf;
int err;

if (!dev->netdev_ops->ndo_xdp_xmit)
return -EOPNOTSUPP;

err = xdp_ok_fwd_dev(dev, xdp->data_end - xdp->data);
err = xdp_ok_fwd_dev(dev, xdpf->len);
if (unlikely(err))
return err;

xdpf = xdp_convert_buff_to_frame(xdp);
if (unlikely(!xdpf))
return -EOVERFLOW;

bq_enqueue(dev, xdpf, dev_rx, xdp_prog);
return 0;
}
Expand Down Expand Up @@ -520,27 +515,27 @@ static u32 dev_map_bpf_prog_run_skb(struct sk_buff *skb, struct bpf_dtab_netdev
return act;
}

int dev_xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp,
int dev_xdp_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
struct net_device *dev_rx)
{
return __xdp_enqueue(dev, xdp, dev_rx, NULL);
return __xdp_enqueue(dev, xdpf, dev_rx, NULL);
}

int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,
int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_frame *xdpf,
struct net_device *dev_rx)
{
struct net_device *dev = dst->dev;

return __xdp_enqueue(dev, xdp, dev_rx, dst->xdp_prog);
return __xdp_enqueue(dev, xdpf, dev_rx, dst->xdp_prog);
}

static bool is_valid_dst(struct bpf_dtab_netdev *obj, struct xdp_buff *xdp)
static bool is_valid_dst(struct bpf_dtab_netdev *obj, struct xdp_frame *xdpf)
{
if (!obj ||
!obj->dev->netdev_ops->ndo_xdp_xmit)
return false;

if (xdp_ok_fwd_dev(obj->dev, xdp->data_end - xdp->data))
if (xdp_ok_fwd_dev(obj->dev, xdpf->len))
return false;

return true;
Expand Down Expand Up @@ -586,14 +581,13 @@ static int get_upper_ifindexes(struct net_device *dev, int *indexes)
return n;
}

int dev_map_enqueue_multi(struct xdp_buff *xdp, struct net_device *dev_rx,
int dev_map_enqueue_multi(struct xdp_frame *xdpf, struct net_device *dev_rx,
struct bpf_map *map, bool exclude_ingress)
{
struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
struct bpf_dtab_netdev *dst, *last_dst = NULL;
int excluded_devices[1+MAX_NEST_DEV];
struct hlist_head *head;
struct xdp_frame *xdpf;
int num_excluded = 0;
unsigned int i;
int err;
Expand All @@ -603,15 +597,11 @@ int dev_map_enqueue_multi(struct xdp_buff *xdp, struct net_device *dev_rx,
excluded_devices[num_excluded++] = dev_rx->ifindex;
}

xdpf = xdp_convert_buff_to_frame(xdp);
if (unlikely(!xdpf))
return -EOVERFLOW;

if (map->map_type == BPF_MAP_TYPE_DEVMAP) {
for (i = 0; i < map->max_entries; i++) {
dst = rcu_dereference_check(dtab->netdev_map[i],
rcu_read_lock_bh_held());
if (!is_valid_dst(dst, xdp))
if (!is_valid_dst(dst, xdpf))
continue;

if (is_ifindex_excluded(excluded_devices, num_excluded, dst->dev->ifindex))
Expand All @@ -634,7 +624,7 @@ int dev_map_enqueue_multi(struct xdp_buff *xdp, struct net_device *dev_rx,
head = dev_map_index_hash(dtab, i);
hlist_for_each_entry_rcu(dst, head, index_hlist,
lockdep_is_held(&dtab->index_lock)) {
if (!is_valid_dst(dst, xdp))
if (!is_valid_dst(dst, xdpf))
continue;

if (is_ifindex_excluded(excluded_devices, num_excluded,
Expand Down
24 changes: 17 additions & 7 deletions net/core/filter.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3964,30 +3964,39 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
enum bpf_map_type map_type = ri->map_type;
void *fwd = ri->tgt_value;
u32 map_id = ri->map_id;
struct xdp_frame *xdpf;
struct bpf_map *map;
int err;

ri->map_id = 0; /* Valid map id idr range: [1,INT_MAX[ */
ri->map_type = BPF_MAP_TYPE_UNSPEC;

if (map_type == BPF_MAP_TYPE_XSKMAP) {
err = __xsk_map_redirect(fwd, xdp);
goto out;
}

xdpf = xdp_convert_buff_to_frame(xdp);
if (unlikely(!xdpf)) {
err = -EOVERFLOW;
goto err;
}

switch (map_type) {
case BPF_MAP_TYPE_DEVMAP:
fallthrough;
case BPF_MAP_TYPE_DEVMAP_HASH:
map = READ_ONCE(ri->map);
if (unlikely(map)) {
WRITE_ONCE(ri->map, NULL);
err = dev_map_enqueue_multi(xdp, dev, map,
err = dev_map_enqueue_multi(xdpf, dev, map,
ri->flags & BPF_F_EXCLUDE_INGRESS);
} else {
err = dev_map_enqueue(fwd, xdp, dev);
err = dev_map_enqueue(fwd, xdpf, dev);
}
break;
case BPF_MAP_TYPE_CPUMAP:
err = cpu_map_enqueue(fwd, xdp, dev);
break;
case BPF_MAP_TYPE_XSKMAP:
err = __xsk_map_redirect(fwd, xdp);
err = cpu_map_enqueue(fwd, xdpf, dev);
break;
case BPF_MAP_TYPE_UNSPEC:
if (map_id == INT_MAX) {
Expand All @@ -3996,14 +4005,15 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
err = -EINVAL;
break;
}
err = dev_xdp_enqueue(fwd, xdp, dev);
err = dev_xdp_enqueue(fwd, xdpf, dev);
break;
}
fallthrough;
default:
err = -EBADRQC;
}

out:
if (unlikely(err))
goto err;

Expand Down

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