diff options
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/filter.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index 5fd5139e8638..35c6933c2622 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2297,6 +2297,137 @@ static const struct bpf_func_proto bpf_msg_pull_data_proto = { .arg4_type = ARG_ANYTHING, }; +BPF_CALL_4(bpf_msg_push_data, struct sk_msg *, msg, u32, start, + u32, len, u64, flags) +{ + struct scatterlist sge, nsge, nnsge, rsge = {0}, *psge; + u32 new, i = 0, l, space, copy = 0, offset = 0; + u8 *raw, *to, *from; + struct page *page; + + if (unlikely(flags)) + return -EINVAL; + + /* First find the starting scatterlist element */ + i = msg->sg.start; + do { + l = sk_msg_elem(msg, i)->length; + + if (start < offset + l) + break; + offset += l; + sk_msg_iter_var_next(i); + } while (i != msg->sg.end); + + if (start >= offset + l) + return -EINVAL; + + space = MAX_MSG_FRAGS - sk_msg_elem_used(msg); + + /* If no space available will fallback to copy, we need at + * least one scatterlist elem available to push data into + * when start aligns to the beginning of an element or two + * when it falls inside an element. We handle the start equals + * offset case because its the common case for inserting a + * header. + */ + if (!space || (space == 1 && start != offset)) + copy = msg->sg.data[i].length; + + page = alloc_pages(__GFP_NOWARN | GFP_ATOMIC | __GFP_COMP, + get_order(copy + len)); + if (unlikely(!page)) + return -ENOMEM; + + if (copy) { + int front, back; + + raw = page_address(page); + + psge = sk_msg_elem(msg, i); + front = start - offset; + back = psge->length - front; + from = sg_virt(psge); + + if (front) + memcpy(raw, from, front); + + if (back) { + from += front; + to = raw + front + len; + + memcpy(to, from, back); + } + + put_page(sg_page(psge)); + } else if (start - offset) { + psge = sk_msg_elem(msg, i); + rsge = sk_msg_elem_cpy(msg, i); + + psge->length = start - offset; + rsge.length -= psge->length; + rsge.offset += start; + + sk_msg_iter_var_next(i); + sg_unmark_end(psge); + sk_msg_iter_next(msg, end); + } + + /* Slot(s) to place newly allocated data */ + new = i; + + /* Shift one or two slots as needed */ + if (!copy) { + sge = sk_msg_elem_cpy(msg, i); + + sk_msg_iter_var_next(i); + sg_unmark_end(&sge); + sk_msg_iter_next(msg, end); + + nsge = sk_msg_elem_cpy(msg, i); + if (rsge.length) { + sk_msg_iter_var_next(i); + nnsge = sk_msg_elem_cpy(msg, i); + } + + while (i != msg->sg.end) { + msg->sg.data[i] = sge; + sge = nsge; + sk_msg_iter_var_next(i); + if (rsge.length) { + nsge = nnsge; + nnsge = sk_msg_elem_cpy(msg, i); + } else { + nsge = sk_msg_elem_cpy(msg, i); + } + } + } + + /* Place newly allocated data buffer */ + sk_mem_charge(msg->sk, len); + msg->sg.size += len; + msg->sg.copy[new] = false; + sg_set_page(&msg->sg.data[new], page, len + copy, 0); + if (rsge.length) { + get_page(sg_page(&rsge)); + sk_msg_iter_var_next(new); + msg->sg.data[new] = rsge; + } + + sk_msg_compute_data_pointers(msg); + return 0; +} + +static const struct bpf_func_proto bpf_msg_push_data_proto = { + .func = bpf_msg_push_data, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_ANYTHING, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_ANYTHING, +}; + BPF_CALL_1(bpf_get_cgroup_classid, const struct sk_buff *, skb) { return task_get_classid(skb); @@ -4854,6 +4985,7 @@ bool bpf_helper_changes_pkt_data(void *func) func == bpf_xdp_adjust_head || func == bpf_xdp_adjust_meta || func == bpf_msg_pull_data || + func == bpf_msg_push_data || func == bpf_xdp_adjust_tail || #if IS_ENABLED(CONFIG_IPV6_SEG6_BPF) func == bpf_lwt_seg6_store_bytes || @@ -5130,6 +5262,8 @@ sk_msg_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_msg_cork_bytes_proto; case BPF_FUNC_msg_pull_data: return &bpf_msg_pull_data_proto; + case BPF_FUNC_msg_push_data: + return &bpf_msg_push_data_proto; case BPF_FUNC_get_local_storage: return &bpf_get_local_storage_proto; default: |