Messages in this thread | | | Date | Sat, 25 Nov 2023 12:36:29 -0800 | Subject | Re: [PATCH ipsec-next v1 1/7] bpf: xfrm: Add bpf_xdp_get_xfrm_state() kfunc | From | Yonghong Song <> |
| |
On 11/22/23 1:20 PM, Daniel Xu wrote: > This commit adds an unstable kfunc helper to access internal xfrm_state > associated with an SA. This is intended to be used for the upcoming > IPsec pcpu work to assign special pcpu SAs to a particular CPU. In other > words: for custom software RSS. > > That being said, the function that this kfunc wraps is fairly generic > and used for a lot of xfrm tasks. I'm sure people will find uses > elsewhere over time. > > Co-developed-by: Antony Antony <antony.antony@secunet.com> > Signed-off-by: Antony Antony <antony.antony@secunet.com> > Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> > --- > include/net/xfrm.h | 9 ++++ > net/xfrm/Makefile | 1 + > net/xfrm/xfrm_policy.c | 2 + > net/xfrm/xfrm_state_bpf.c | 111 ++++++++++++++++++++++++++++++++++++++ > 4 files changed, 123 insertions(+) > create mode 100644 net/xfrm/xfrm_state_bpf.c > > 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..0c1f2f91125c > --- /dev/null > +++ b/net/xfrm/xfrm_state_bpf.c > @@ -0,0 +1,111 @@ > +// 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_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 - Passed NULL for opts > + * -EINVAL - opts__sz isn't BPF_XFRM_STATE_OPTS_SZ > + * -ENONET - No network namespace found for netns_id > + * @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 - L3 protocol to match on > + * @family - L3 protocol family to match on > + */ > +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), > +}; > + > +__diag_push(); > +__diag_ignore_all("-Wmissing-prototypes", > + "Global functions as their definitions will be in xfrm_state BTF"); > + > +/* bpf_xdp_get_xfrm_state - Get XFRM state > + * > + * 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 != BPF_XFRM_STATE_OPTS_SZ) { > + opts->error = -EINVAL;
If opts is NULL, obvious we have issue opts->error access. If opts is not NULL and opts_sz < 4, we also have issue with opts->error access since it may override some other stuff on the stack.
In such cases, we do not need to do 'opts->error = -EINVAL' and can simply 'return NULL'. bpf program won't be able to check opts->error anyway since the opts is either NULL or opts_sz < 4.
> + 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); > + > + return x; > +} > + > +__diag_pop()
[...]
| |