diff options
| -rw-r--r-- | include/net/xfrm.h | 9 | ||||
| -rw-r--r-- | net/xfrm/Makefile | 1 | ||||
| -rw-r--r-- | net/xfrm/xfrm_policy.c | 2 | ||||
| -rw-r--r-- | net/xfrm/xfrm_state_bpf.c | 134 |
4 files changed, 146 insertions, 0 deletions
diff --git a/include/net/xfrm.h b/include/net/xfrm.h index c9bb0f892f55..1d107241b901 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -2190,4 +2190,13 @@ static inline int register_xfrm_interface_bpf(void) #endif +#if IS_ENABLED(CONFIG_DEBUG_INFO_BTF) +int register_xfrm_state_bpf(void); +#else +static inline int register_xfrm_state_bpf(void) +{ + return 0; +} +#endif + #endif /* _NET_XFRM_H */ diff --git a/net/xfrm/Makefile b/net/xfrm/Makefile index cd47f88921f5..547cec77ba03 100644 --- a/net/xfrm/Makefile +++ b/net/xfrm/Makefile @@ -21,3 +21,4 @@ obj-$(CONFIG_XFRM_USER_COMPAT) += xfrm_compat.o obj-$(CONFIG_XFRM_IPCOMP) += xfrm_ipcomp.o obj-$(CONFIG_XFRM_INTERFACE) += xfrm_interface.o obj-$(CONFIG_XFRM_ESPINTCP) += espintcp.o +obj-$(CONFIG_DEBUG_INFO_BTF) += xfrm_state_bpf.o diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index c13dc3ef7910..1b7e75159727 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -4218,6 +4218,8 @@ void __init xfrm_init(void) #ifdef CONFIG_XFRM_ESPINTCP espintcp_init(); #endif + + register_xfrm_state_bpf(); } #ifdef CONFIG_AUDITSYSCALL diff --git a/net/xfrm/xfrm_state_bpf.c b/net/xfrm/xfrm_state_bpf.c new file mode 100644 index 000000000000..9e20d4a377f7 --- /dev/null +++ b/net/xfrm/xfrm_state_bpf.c @@ -0,0 +1,134 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Unstable XFRM state BPF helpers. + * + * Note that it is allowed to break compatibility for these functions since the + * interface they are exposed through to BPF programs is explicitly unstable. + */ + +#include <linux/bpf.h> +#include <linux/btf.h> +#include <linux/btf_ids.h> +#include <net/xdp.h> +#include <net/xfrm.h> + +/* bpf_xfrm_state_opts - Options for XFRM state lookup helpers + * + * Members: + * @error - Out parameter, set for any errors encountered + * Values: + * -EINVAL - netns_id is less than -1 + * -EINVAL - opts__sz isn't BPF_XFRM_STATE_OPTS_SZ + * -ENONET - No network namespace found for netns_id + * -ENOENT - No xfrm_state found + * @netns_id - Specify the network namespace for lookup + * Values: + * BPF_F_CURRENT_NETNS (-1) + * Use namespace associated with ctx + * [0, S32_MAX] + * Network Namespace ID + * @mark - XFRM mark to match on + * @daddr - Destination address to match on + * @spi - Security parameter index to match on + * @proto - IP protocol to match on (eg. IPPROTO_ESP) + * @family - Protocol family to match on (AF_INET/AF_INET6) + */ +struct bpf_xfrm_state_opts { + s32 error; + s32 netns_id; + u32 mark; + xfrm_address_t daddr; + __be32 spi; + u8 proto; + u16 family; +}; + +enum { + BPF_XFRM_STATE_OPTS_SZ = sizeof(struct bpf_xfrm_state_opts), +}; + +__bpf_kfunc_start_defs(); + +/* bpf_xdp_get_xfrm_state - Get XFRM state + * + * A `struct xfrm_state *`, if found, must be released with a corresponding + * bpf_xdp_xfrm_state_release. + * + * Parameters: + * @ctx - Pointer to ctx (xdp_md) in XDP program + * Cannot be NULL + * @opts - Options for lookup (documented above) + * Cannot be NULL + * @opts__sz - Length of the bpf_xfrm_state_opts structure + * Must be BPF_XFRM_STATE_OPTS_SZ + */ +__bpf_kfunc struct xfrm_state * +bpf_xdp_get_xfrm_state(struct xdp_md *ctx, struct bpf_xfrm_state_opts *opts, u32 opts__sz) +{ + struct xdp_buff *xdp = (struct xdp_buff *)ctx; + struct net *net = dev_net(xdp->rxq->dev); + struct xfrm_state *x; + + if (!opts || opts__sz < sizeof(opts->error)) + return NULL; + + if (opts__sz != BPF_XFRM_STATE_OPTS_SZ) { + opts->error = -EINVAL; + return NULL; + } + + if (unlikely(opts->netns_id < BPF_F_CURRENT_NETNS)) { + opts->error = -EINVAL; + return NULL; + } + + if (opts->netns_id >= 0) { + net = get_net_ns_by_id(net, opts->netns_id); + if (unlikely(!net)) { + opts->error = -ENONET; + return NULL; + } + } + + x = xfrm_state_lookup(net, opts->mark, &opts->daddr, opts->spi, + opts->proto, opts->family); + + if (opts->netns_id >= 0) + put_net(net); + if (!x) + opts->error = -ENOENT; + + return x; +} + +/* bpf_xdp_xfrm_state_release - Release acquired xfrm_state object + * + * This must be invoked for referenced PTR_TO_BTF_ID, and the verifier rejects + * the program if any references remain in the program in all of the explored + * states. + * + * Parameters: + * @x - Pointer to referenced xfrm_state object, obtained using + * bpf_xdp_get_xfrm_state. + */ +__bpf_kfunc void bpf_xdp_xfrm_state_release(struct xfrm_state *x) +{ + xfrm_state_put(x); +} + +__bpf_kfunc_end_defs(); + +BTF_SET8_START(xfrm_state_kfunc_set) +BTF_ID_FLAGS(func, bpf_xdp_get_xfrm_state, KF_RET_NULL | KF_ACQUIRE) +BTF_ID_FLAGS(func, bpf_xdp_xfrm_state_release, KF_RELEASE) +BTF_SET8_END(xfrm_state_kfunc_set) + +static const struct btf_kfunc_id_set xfrm_state_xdp_kfunc_set = { + .owner = THIS_MODULE, + .set = &xfrm_state_kfunc_set, +}; + +int __init register_xfrm_state_bpf(void) +{ + return register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, + &xfrm_state_xdp_kfunc_set); +} |