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recvmsg.go
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recvmsg.go
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// MIT License
//
// Copyright (c) 2023 Paweł Gaczyński
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
package giouring
import (
"syscall"
"unsafe"
)
// liburing: CMSG_ALIGN
func cmsgAlign(length uint64) uint64 {
return (length + uint64(unsafe.Sizeof(uintptr(0))) - 1) & ^(uint64(unsafe.Sizeof(uintptr(0))) - 1)
}
// liburing: io_uring_recvmsg_cmsg_nexthdr - https://manpages.debian.org/unstable/liburing-dev/io_uring_recvmsg_cmsg_nexthdr.3.en.html
func (o *RecvmsgOut) CmsgNexthdr(msgh *syscall.Msghdr, cmsg *syscall.Cmsghdr) *syscall.Cmsghdr {
if cmsg.Len < syscall.SizeofCmsghdr {
return nil
}
end := (*byte)(unsafe.Pointer(uintptr(unsafe.Pointer(o.CmsgFirsthdr(msgh))) + uintptr(o.ControlLen)))
cmsg = (*syscall.Cmsghdr)(unsafe.Pointer(uintptr(unsafe.Pointer(cmsg)) + uintptr(cmsgAlign(cmsg.Len))))
if uintptr(unsafe.Pointer(cmsg))+unsafe.Sizeof(*cmsg) > uintptr(unsafe.Pointer(end)) {
return nil
}
if uintptr(unsafe.Pointer(cmsg))+uintptr(cmsgAlign(cmsg.Len)) > uintptr(unsafe.Pointer(end)) {
return nil
}
return cmsg
}
// liburing: io_uring_recvmsg_name - https://manpages.debian.org/unstable/liburing-dev/io_uring_recvmsg_name.3.en.html
func (o *RecvmsgOut) Name() unsafe.Pointer {
return unsafe.Pointer(uintptr(unsafe.Pointer(o)) + unsafe.Sizeof(*o))
}
// liburing: io_uring_recvmsg_cmsg_firsthdr - https://manpages.debian.org/unstable/liburing-dev/io_uring_recvmsg_cmsg_firsthdr.3.en.html
func (o *RecvmsgOut) CmsgFirsthdr(msgh *syscall.Msghdr) *syscall.Cmsghdr {
if o.ControlLen < syscall.SizeofCmsghdr {
return nil
}
return (*syscall.Cmsghdr)(unsafe.Pointer(uintptr(o.Name()) + uintptr(msgh.Namelen)))
}
// liburing: io_uring_recvmsg_payload - https://manpages.debian.org/unstable/liburing-dev/io_uring_recvmsg_payload.3.en.html
func (o *RecvmsgOut) Payload(msgh *syscall.Msghdr) unsafe.Pointer {
return unsafe.Pointer(uintptr(unsafe.Pointer(o)) +
unsafe.Sizeof(*o) +
uintptr(msgh.Namelen) +
uintptr(msgh.Controllen))
}
// liburing: io_uring_recvmsg_payload_length - https://manpages.debian.org/unstable/liburing-dev/io_uring_recvmsg_payload_length.3.en.html
func (o *RecvmsgOut) PayloadLength(bufLen int, msgh *syscall.Msghdr) uint32 {
payloadStart := uintptr(o.Payload(msgh))
payloadEnd := uintptr(unsafe.Pointer(o)) + uintptr(bufLen)
return uint32(payloadEnd - payloadStart)
}
// liburing: io_uring_recvmsg_validate - https://manpages.debian.org/unstable/liburing-dev/io_uring_recvmsg_validate.3.en.html
func RecvmsgValidate(buf unsafe.Pointer, bufLen int, msgh *syscall.Msghdr) *RecvmsgOut {
header := uintptr(msgh.Controllen) + uintptr(msgh.Namelen) + unsafe.Sizeof(RecvmsgOut{})
if bufLen < 0 || uintptr(bufLen) < header {
return nil
}
return (*RecvmsgOut)(buf)
}