On Thu, Sep 03, 2020 at 10:58:51PM +0200, Lorenzo Bianconi wrote: > From: Sameeh Jubran <sameehj@xxxxxxxxxx> > > The implementation is based on this [0] draft by Jesper D. Brouer. > > Provided two new helpers: > > * bpf_xdp_get_frag_count() > * bpf_xdp_get_frags_total_size() > > [0] xdp mb design - https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org > Signed-off-by: Sameeh Jubran <sameehj@xxxxxxxxxx> > Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx> > --- > include/uapi/linux/bpf.h | 14 ++++++++++++ > net/core/filter.c | 39 ++++++++++++++++++++++++++++++++++ > tools/include/uapi/linux/bpf.h | 14 ++++++++++++ > 3 files changed, 67 insertions(+) > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > index c4a6d245619c..53db75095306 100644 > --- a/include/uapi/linux/bpf.h > +++ b/include/uapi/linux/bpf.h > @@ -3590,6 +3590,18 @@ union bpf_attr { > * > * Return > * 0 on success, or a negative error in case of failure. > + * > + * int bpf_xdp_get_frag_count(struct xdp_buff *xdp_md) > + * Description > + * Get the total number of frags for a given packet. > + * Return > + * The number of frags > + * > + * int bpf_xdp_get_frags_total_size(struct xdp_buff *xdp_md) > + * Description > + * Get the total size of frags for a given packet. > + * Return > + * The total size of frags for a given packet. > */ > #define __BPF_FUNC_MAPPER(FN) \ > FN(unspec), \ > @@ -3742,6 +3754,8 @@ union bpf_attr { > FN(d_path), \ > FN(copy_from_user), \ > FN(xdp_adjust_mb_header), \ > + FN(xdp_get_frag_count), \ > + FN(xdp_get_frags_total_size), \ > /* */ > > /* integer value in 'imm' field of BPF_CALL instruction selects which helper > diff --git a/net/core/filter.c b/net/core/filter.c > index ae6b10cf062d..ba058fc16440 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -3526,6 +3526,41 @@ static const struct bpf_func_proto bpf_xdp_adjust_mb_header_proto = { > .arg2_type = ARG_ANYTHING, > }; > > +BPF_CALL_1(bpf_xdp_get_frag_count, struct xdp_buff*, xdp) > +{ > + struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp); > + > + return xdp->mb ? sinfo->nr_frags : 0; > +} > + > +const struct bpf_func_proto bpf_xdp_get_frag_count_proto = { > + .func = bpf_xdp_get_frag_count, > + .gpl_only = false, > + .ret_type = RET_INTEGER, > + .arg1_type = ARG_PTR_TO_CTX, > +}; > + > +BPF_CALL_1(bpf_xdp_get_frags_total_size, struct xdp_buff*, xdp) > +{ > + struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp); > + int nfrags, i; > + int size = 0; > + > + nfrags = xdp->mb ? sinfo->nr_frags : 0; > + > + for (i = 0; i < nfrags && i < MAX_SKB_FRAGS; i++) > + size += skb_frag_size(&sinfo->frags[i]); > + I only quickly jumped through series and IMHO this helper should be rewritten/optimized in a way that we bail out as early as possible if !xdp->mb as the rest of the code on that condition will do nothing and i'm not sure if compiler would optimize it. struct skb_shared_info *sinfo; int nfrags, i; int size = 0; if (!xdp->mb) return 0; sinfo = xdp_get_shared_info_from_buff(xdp); nfrags = min(sinfo->nr_frags, MAX_SKB_FRAGS); for (i = 0; i < nfrags; i++) size += skb_frag_size(&sinfo->frags[i]); return size; Thoughts? > + return size; > +} > + > +const struct bpf_func_proto bpf_xdp_get_frags_total_size_proto = { > + .func = bpf_xdp_get_frags_total_size, > + .gpl_only = false, > + .ret_type = RET_INTEGER, > + .arg1_type = ARG_PTR_TO_CTX, > +}; > + > BPF_CALL_2(bpf_xdp_adjust_tail, struct xdp_buff *, xdp, int, offset) > { > void *data_hard_end = xdp_data_hard_end(xdp); /* use xdp->frame_sz */ > @@ -6889,6 +6924,10 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > return &bpf_xdp_adjust_tail_proto; > case BPF_FUNC_xdp_adjust_mb_header: > return &bpf_xdp_adjust_mb_header_proto; > + case BPF_FUNC_xdp_get_frag_count: > + return &bpf_xdp_get_frag_count_proto; > + case BPF_FUNC_xdp_get_frags_total_size: > + return &bpf_xdp_get_frags_total_size_proto; > case BPF_FUNC_fib_lookup: > return &bpf_xdp_fib_lookup_proto; > #ifdef CONFIG_INET > diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h > index 392d52a2ecef..dd4669096cbb 100644 > --- a/tools/include/uapi/linux/bpf.h > +++ b/tools/include/uapi/linux/bpf.h > @@ -3591,6 +3591,18 @@ union bpf_attr { > * > * Return > * 0 on success, or a negative error in case of failure. > + * > + * int bpf_xdp_get_frag_count(struct xdp_buff *xdp_md) > + * Description > + * Get the total number of frags for a given packet. > + * Return > + * The number of frags > + * > + * int bpf_xdp_get_frags_total_size(struct xdp_buff *xdp_md) > + * Description > + * Get the total size of frags for a given packet. > + * Return > + * The total size of frags for a given packet. > */ > #define __BPF_FUNC_MAPPER(FN) \ > FN(unspec), \ > @@ -3743,6 +3755,8 @@ union bpf_attr { > FN(d_path), \ > FN(copy_from_user), \ > FN(xdp_adjust_mb_header), \ > + FN(xdp_get_frag_count), \ > + FN(xdp_get_frags_total_size), \ > /* */ > > /* integer value in 'imm' field of BPF_CALL instruction selects which helper > -- > 2.26.2 >
