[PATCH net-next v2 04/18] bpf, xdp: constify some bpf_prog * function arguments

Alexander Lobakin
2024-10-15T14:54:30Z

In lots of places, bpf_prog pointer is used only for tracing or other
stuff that doesn't modify the structure itself. Same for net_device.
Address at least some of them and add `const` attributes there. The
object code didn't change, but that may prevent unwanted data
modifications and also allow more helpers to have const arguments.

Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
include/linux/bpf.h | 12 ++++++------
include/linux/filter.h | 9 +++++----
include/linux/netdevice.h | 6 +++---
include/linux/skbuff.h | 2 +-
kernel/bpf/devmap.c | 8 ++++----
net/core/dev.c | 10 +++++-----
net/core/filter.c | 29 ++++++++++++++++-------------
net/core/skbuff.c | 2 +-
8 files changed, 41 insertions(+), 37 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 19d8ca8ac960..263515478984 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2534,10 +2534,10 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_frame *xdpf,
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);
+ const struct bpf_prog *xdp_prog);
int dev_map_redirect_multi(struct net_device *dev, struct sk_buff *skb,
- struct bpf_prog *xdp_prog, struct bpf_map *map,
- bool exclude_ingress);
+ const struct bpf_prog *xdp_prog,
+ struct bpf_map *map, bool exclude_ingress);

void __cpu_map_flush(struct list_head *flush_list);
int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf,
@@ -2801,15 +2801,15 @@ struct sk_buff;

static inline int dev_map_generic_redirect(struct bpf_dtab_netdev *dst,
struct sk_buff *skb,
- struct bpf_prog *xdp_prog)
+ const struct bpf_prog *xdp_prog)
{
return 0;
}

static inline
int dev_map_redirect_multi(struct net_device *dev, struct sk_buff *skb,
- struct bpf_prog *xdp_prog, struct bpf_map *map,
- bool exclude_ingress)
+ const struct bpf_prog *xdp_prog,
+ struct bpf_map *map, bool exclude_ingress)
{
return 0;
}
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 7d7578a8eac1..ee067ab13272 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1178,17 +1178,18 @@ static inline int xdp_ok_fwd_dev(const struct net_device *fwd,
* This does not appear to be a real limitation for existing software.
*/
int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb,
- struct xdp_buff *xdp, struct bpf_prog *prog);
+ struct xdp_buff *xdp, const struct bpf_prog *prog);
int xdp_do_redirect(struct net_device *dev,
struct xdp_buff *xdp,
- struct bpf_prog *prog);
+ const struct bpf_prog *prog);
int xdp_do_redirect_frame(struct net_device *dev,
struct xdp_buff *xdp,
struct xdp_frame *xdpf,
- struct bpf_prog *prog);
+ const struct bpf_prog *prog);
void xdp_do_flush(void);

-void bpf_warn_invalid_xdp_action(struct net_device *dev, struct bpf_prog *prog, u32 act);
+void bpf_warn_invalid_xdp_action(const struct net_device *dev,
+ const struct bpf_prog *prog, u32 act);

#ifdef CONFIG_INET
struct sock *bpf_run_sk_reuseport(struct sock_reuseport *reuse, struct sock *sk,
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 8feaca12655e..72f53e7610ec 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3932,9 +3932,9 @@ static inline void dev_consume_skb_any(struct sk_buff *skb)
}

u32 bpf_prog_run_generic_xdp(struct sk_buff *skb, struct xdp_buff *xdp,
- struct bpf_prog *xdp_prog);
-void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog);
-int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb);
+ const struct bpf_prog *xdp_prog);
+void generic_xdp_tx(struct sk_buff *skb, const struct bpf_prog *xdp_prog);
+int do_xdp_generic(const struct bpf_prog *xdp_prog, struct sk_buff **pskb);
int netif_rx(struct sk_buff *skb);
int __netif_rx(struct sk_buff *skb);

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index f187a2415fb8..c867df5b1051 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3595,7 +3595,7 @@ static inline netmem_ref skb_frag_netmem(const skb_frag_t *frag)
int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb,
unsigned int headroom);
int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb,
- struct bpf_prog *prog);
+ const struct bpf_prog *prog);

/**
* skb_frag_address - gets the address of the data contained in a paged fragment
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 9e0e3b0a18e4..f634b87aa0fa 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -675,7 +675,7 @@ int dev_map_enqueue_multi(struct xdp_frame *xdpf, struct net_device *dev_rx,
}

int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
- struct bpf_prog *xdp_prog)
+ const struct bpf_prog *xdp_prog)
{
int err;

@@ -698,7 +698,7 @@ int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,

static int dev_map_redirect_clone(struct bpf_dtab_netdev *dst,
struct sk_buff *skb,
- struct bpf_prog *xdp_prog)
+ const struct bpf_prog *xdp_prog)
{
struct sk_buff *nskb;
int err;
@@ -717,8 +717,8 @@ static int dev_map_redirect_clone(struct bpf_dtab_netdev *dst,
}

int dev_map_redirect_multi(struct net_device *dev, struct sk_buff *skb,
- struct bpf_prog *xdp_prog, struct bpf_map *map,
- bool exclude_ingress)
+ const struct bpf_prog *xdp_prog,
+ 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;
diff --git a/net/core/dev.c b/net/core/dev.c
index c682173a7642..b857abb5c0e9 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4927,7 +4927,7 @@ static struct netdev_rx_queue *netif_get_rxqueue(struct sk_buff *skb)
}

u32 bpf_prog_run_generic_xdp(struct sk_buff *skb, struct xdp_buff *xdp,
- struct bpf_prog *xdp_prog)
+ const struct bpf_prog *xdp_prog)
{
void *orig_data, *orig_data_end, *hard_start;
struct netdev_rx_queue *rxqueue;
@@ -5029,7 +5029,7 @@ u32 bpf_prog_run_generic_xdp(struct sk_buff *skb, struct xdp_buff *xdp,
}

static int
-netif_skb_check_for_xdp(struct sk_buff **pskb, struct bpf_prog *prog)
+netif_skb_check_for_xdp(struct sk_buff **pskb, const struct bpf_prog *prog)
{
struct sk_buff *skb = *pskb;
int err, hroom, troom;
@@ -5053,7 +5053,7 @@ netif_skb_check_for_xdp(struct sk_buff **pskb, struct bpf_prog *prog)

static u32 netif_receive_generic_xdp(struct sk_buff **pskb,
struct xdp_buff *xdp,
- struct bpf_prog *xdp_prog)
+ const struct bpf_prog *xdp_prog)
{
struct sk_buff *skb = *pskb;
u32 mac_len, act = XDP_DROP;
@@ -5106,7 +5106,7 @@ static u32 netif_receive_generic_xdp(struct sk_buff **pskb,
* and DDOS attacks will be more effective. In-driver-XDP use dedicated TX
* queues, so they do not have this starvation issue.
*/
-void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog)
+void generic_xdp_tx(struct sk_buff *skb, const struct bpf_prog *xdp_prog)
{
struct net_device *dev = skb->dev;
struct netdev_queue *txq;
@@ -5131,7 +5131,7 @@ void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog)

static DEFINE_STATIC_KEY_FALSE(generic_xdp_needed_key);

-int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
+int do_xdp_generic(const struct bpf_prog *xdp_prog, struct sk_buff **pskb)
{
struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;

diff --git a/net/core/filter.c b/net/core/filter.c
index a88e6924c4c0..8dfa9493d2f3 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4349,9 +4349,9 @@ u32 xdp_master_redirect(struct xdp_buff *xdp)
EXPORT_SYMBOL_GPL(xdp_master_redirect);

static inline int __xdp_do_redirect_xsk(struct bpf_redirect_info *ri,
- struct net_device *dev,
+ const struct net_device *dev,
struct xdp_buff *xdp,
- struct bpf_prog *xdp_prog)
+ const struct bpf_prog *xdp_prog)
{
enum bpf_map_type map_type = ri->map_type;
void *fwd = ri->tgt_value;
@@ -4372,10 +4372,10 @@ static inline int __xdp_do_redirect_xsk(struct bpf_redirect_info *ri,
return err;
}

-static __always_inline int __xdp_do_redirect_frame(struct bpf_redirect_info *ri,
- struct net_device *dev,
- struct xdp_frame *xdpf,
- struct bpf_prog *xdp_prog)
+static __always_inline int
+__xdp_do_redirect_frame(struct bpf_redirect_info *ri, struct net_device *dev,
+ struct xdp_frame *xdpf,
+ const struct bpf_prog *xdp_prog)
{
enum bpf_map_type map_type = ri->map_type;
void *fwd = ri->tgt_value;
@@ -4444,7 +4444,7 @@ static __always_inline int __xdp_do_redirect_frame(struct bpf_redirect_info *ri,
}

int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
- struct bpf_prog *xdp_prog)
+ const struct bpf_prog *xdp_prog)
{
struct bpf_redirect_info *ri = bpf_net_ctx_get_ri();
enum bpf_map_type map_type = ri->map_type;
@@ -4458,7 +4458,8 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
EXPORT_SYMBOL_GPL(xdp_do_redirect);

int xdp_do_redirect_frame(struct net_device *dev, struct xdp_buff *xdp,
- struct xdp_frame *xdpf, struct bpf_prog *xdp_prog)
+ struct xdp_frame *xdpf,
+ const struct bpf_prog *xdp_prog)
{
struct bpf_redirect_info *ri = bpf_net_ctx_get_ri();
enum bpf_map_type map_type = ri->map_type;
@@ -4473,9 +4474,9 @@ EXPORT_SYMBOL_GPL(xdp_do_redirect_frame);
static int xdp_do_generic_redirect_map(struct net_device *dev,
struct sk_buff *skb,
struct xdp_buff *xdp,
- struct bpf_prog *xdp_prog, void *fwd,
- enum bpf_map_type map_type, u32 map_id,
- u32 flags)
+ const struct bpf_prog *xdp_prog,
+ void *fwd, enum bpf_map_type map_type,
+ u32 map_id, u32 flags)
{
struct bpf_redirect_info *ri = bpf_net_ctx_get_ri();
struct bpf_map *map;
@@ -4529,7 +4530,8 @@ static int xdp_do_generic_redirect_map(struct net_device *dev,
}

int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb,
- struct xdp_buff *xdp, struct bpf_prog *xdp_prog)
+ struct xdp_buff *xdp,
+ const struct bpf_prog *xdp_prog)
{
struct bpf_redirect_info *ri = bpf_net_ctx_get_ri();
enum bpf_map_type map_type = ri->map_type;
@@ -9088,7 +9090,8 @@ static bool xdp_is_valid_access(int off, int size,
return __is_valid_xdp_access(off, size);
}

-void bpf_warn_invalid_xdp_action(struct net_device *dev, struct bpf_prog *prog, u32 act)
+void bpf_warn_invalid_xdp_action(const struct net_device *dev,
+ const struct bpf_prog *prog, u32 act)
{
const u32 act_max = XDP_REDIRECT;

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 00afeb90c23a..224cfe8b4368 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1009,7 +1009,7 @@ int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb,
EXPORT_SYMBOL(skb_pp_cow_data);

int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb,
- struct bpf_prog *prog)
+ const struct bpf_prog *prog)
{
if (!prog->aux->xdp_has_frags)
return -EINVAL;
--
2.46.2