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authorDavid Ahern <dsahern@kernel.org>2020-05-29 16:07:13 -0600
committerAlexei Starovoitov <ast@kernel.org>2020-06-01 14:48:32 -0700
commitfbee97feed9b3e4acdf9590e1f6b4a2eefecfffe (patch)
tree0a0db20d9c9840d8b1988c1960a0c25a21713d59 /net
parent7f1c04269fe7b3293dea38ea65da4fd6614d6f80 (diff)
bpf: Add support to attach bpf program to a devmap entry
Add BPF_XDP_DEVMAP attach type for use with programs associated with a DEVMAP entry. Allow DEVMAPs to associate a program with a device entry by adding a bpf_prog.fd to 'struct bpf_devmap_val'. Values read show the program id, so the fd and id are a union. bpf programs can get access to the struct via vmlinux.h. The program associated with the fd must have type XDP with expected attach type BPF_XDP_DEVMAP. When a program is associated with a device index, the program is run on an XDP_REDIRECT and before the buffer is added to the per-cpu queue. At this point rxq data is still valid; the next patch adds tx device information allowing the prorgam to see both ingress and egress device indices. XDP generic is skb based and XDP programs do not work with skb's. Block the use case by walking maps used by a program that is to be attached via xdpgeneric and fail if any of them are DEVMAP / DEVMAP_HASH with Block attach of BPF_XDP_DEVMAP programs to devices. Signed-off-by: David Ahern <dsahern@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20200529220716.75383-3-dsahern@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/core/dev.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index ae37586f6ee8..10684833f864 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5420,6 +5420,18 @@ static int generic_xdp_install(struct net_device *dev, struct netdev_bpf *xdp)
struct bpf_prog *new = xdp->prog;
int ret = 0;
+ if (new) {
+ u32 i;
+
+ /* generic XDP does not work with DEVMAPs that can
+ * have a bpf_prog installed on an entry
+ */
+ for (i = 0; i < new->aux->used_map_cnt; i++) {
+ if (dev_map_can_have_prog(new->aux->used_maps[i]))
+ return -EINVAL;
+ }
+ }
+
switch (xdp->command) {
case XDP_SETUP_PROG:
rcu_assign_pointer(dev->xdp_prog, new);
@@ -8835,6 +8847,12 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
return -EINVAL;
}
+ if (prog->expected_attach_type == BPF_XDP_DEVMAP) {
+ NL_SET_ERR_MSG(extack, "BPF_XDP_DEVMAP programs can not be attached to a device");
+ bpf_prog_put(prog);
+ return -EINVAL;
+ }
+
/* prog->aux->id may be 0 for orphaned device-bound progs */
if (prog->aux->id && prog->aux->id == prog_id) {
bpf_prog_put(prog);