From: Sameeh Jubran <same...@amazon.com> The implementation is based on this [0] draft by Jesper D. Brouer.
Provided two helpers: * bpf_xdp_get_frag() * bpf_xdp_get_frag_count() [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 <same...@amazon.com> --- include/uapi/linux/bpf.h | 13 +++++++++ net/core/filter.c | 60 ++++++++++++++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 13 +++++++++ 3 files changed, 86 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 5e3863899..3484e481a 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3320,6 +3320,17 @@ union bpf_attr { * A non-negative value equal to or less than *size* on success, * or a negative error in case of failure. * + * int bpf_xdp_get_frag(struct xdp_buff *xdp_md, u32 frag_index, u32 *size, u32 *offset) + * Description + * Get the offset from containing page and size of a given frag. + * 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 */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3464,6 +3475,8 @@ union bpf_attr { FN(skc_to_tcp_request_sock), \ FN(skc_to_udp6_sock), \ FN(get_task_stack), \ + FN(xdp_get_frag), \ + FN(xdp_get_frag_count), \ /* */ /* 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 bdd2382e6..93e790d7b 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3452,6 +3452,62 @@ static const struct bpf_func_proto bpf_xdp_adjust_head_proto = { .arg2_type = ARG_ANYTHING, }; +static inline bool __bpf_xdp_has_frags(struct xdp_buff *xdp) +{ + return xdp->mb != 0; +} + +BPF_CALL_1(bpf_xdp_get_frag_count, struct xdp_buff*, xdp) +{ + return __bpf_xdp_has_frags(xdp) ? + ((struct skb_shared_info *)xdp->data_end)->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_4(bpf_xdp_get_frag, struct xdp_buff*, xdp, u32, frag_index, + u32*, size, u32*, offset) +{ + skb_frag_t *frags; + u32 frag_size; + u16 nr_frags; + struct skb_shared_info *skb_info; + + if (!__bpf_xdp_has_frags(xdp)) + return -EINVAL; + + skb_info = xdp_data_hard_end(xdp); + frags = skb_info->frags; + nr_frags = skb_info->nr_frags; + + if (frag_index >= nr_frags) + return -EINVAL; + + frag_size = frags[frag_index].bv_len; + + if (size) + memcpy(size, &frag_size, sizeof(frag_size)); + if (offset) + memcpy(offset, &frags[frag_index].bv_offset, sizeof(frags[frag_index].bv_offset)); + + return 0; +} + +const struct bpf_func_proto bpf_xdp_get_frag_proto = { + .func = bpf_xdp_get_frag, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_ANYTHING, + .arg3_type = ARG_PTR_TO_INT, + .arg4_type = ARG_PTR_TO_INT, +}; + 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 */ @@ -6475,6 +6531,10 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_xdp_redirect_map_proto; case BPF_FUNC_xdp_adjust_tail: return &bpf_xdp_adjust_tail_proto; + case BPF_FUNC_xdp_get_frag_count: + return &bpf_xdp_get_frag_count_proto; + case BPF_FUNC_xdp_get_frag: + return &bpf_xdp_get_frag_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 5e3863899..3484e481a 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3320,6 +3320,17 @@ union bpf_attr { * A non-negative value equal to or less than *size* on success, * or a negative error in case of failure. * + * int bpf_xdp_get_frag(struct xdp_buff *xdp_md, u32 frag_index, u32 *size, u32 *offset) + * Description + * Get the offset from containing page and size of a given frag. + * 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 */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3464,6 +3475,8 @@ union bpf_attr { FN(skc_to_tcp_request_sock), \ FN(skc_to_udp6_sock), \ FN(get_task_stack), \ + FN(xdp_get_frag), \ + FN(xdp_get_frag_count), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper -- 2.16.6
