linux-stable/include/uapi/linux/errqueue.h
Willem de Bruijn eba75c587e icmp: support rfc 4884
Add setsockopt SOL_IP/IP_RECVERR_4884 to return the offset to an
extension struct if present.

ICMP messages may include an extension structure after the original
datagram. RFC 4884 standardized this behavior. It stores the offset
in words to the extension header in u8 icmphdr.un.reserved[1].

The field is valid only for ICMP types destination unreachable, time
exceeded and parameter problem, if length is at least 128 bytes and
entire packet does not exceed 576 bytes.

Return the offset to the start of the extension struct when reading an
ICMP error from the error queue, if it matches the above constraints.

Do not return the raw u8 field. Return the offset from the start of
the user buffer, in bytes. The kernel does not return the network and
transport headers, so subtract those.

Also validate the headers. Return the offset regardless of validation,
as an invalid extension must still not be misinterpreted as part of
the original datagram. Note that !invalid does not imply valid. If
the extension version does not match, no validation can take place,
for instance.

For backward compatibility, make this optional, set by setsockopt
SOL_IP/IP_RECVERR_RFC4884. For API example and feature test, see
github.com/wdebruij/kerneltools/blob/master/tests/recv_icmp_v2.c

For forward compatibility, reserve only setsockopt value 1, leaving
other bits for additional icmp extensions.

Changes
  v1->v2:
  - convert word offset to byte offset from start of user buffer
    - return in ee_data as u8 may be insufficient
  - define extension struct and object header structs
  - return len only if constraints met
  - if returning len, also validate

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-19 19:20:22 -07:00

78 lines
2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _UAPI_LINUX_ERRQUEUE_H
#define _UAPI_LINUX_ERRQUEUE_H
#include <linux/types.h>
#include <linux/time_types.h>
/* RFC 4884: return offset to extension struct + validation */
struct sock_ee_data_rfc4884 {
__u16 len;
__u8 flags;
__u8 reserved;
};
struct sock_extended_err {
__u32 ee_errno;
__u8 ee_origin;
__u8 ee_type;
__u8 ee_code;
__u8 ee_pad;
__u32 ee_info;
union {
__u32 ee_data;
struct sock_ee_data_rfc4884 ee_rfc4884;
};
};
#define SO_EE_ORIGIN_NONE 0
#define SO_EE_ORIGIN_LOCAL 1
#define SO_EE_ORIGIN_ICMP 2
#define SO_EE_ORIGIN_ICMP6 3
#define SO_EE_ORIGIN_TXSTATUS 4
#define SO_EE_ORIGIN_ZEROCOPY 5
#define SO_EE_ORIGIN_TXTIME 6
#define SO_EE_ORIGIN_TIMESTAMPING SO_EE_ORIGIN_TXSTATUS
#define SO_EE_OFFENDER(ee) ((struct sockaddr*)((ee)+1))
#define SO_EE_CODE_ZEROCOPY_COPIED 1
#define SO_EE_CODE_TXTIME_INVALID_PARAM 1
#define SO_EE_CODE_TXTIME_MISSED 2
#define SO_EE_RFC4884_FLAG_INVALID 1
/**
* struct scm_timestamping - timestamps exposed through cmsg
*
* The timestamping interfaces SO_TIMESTAMPING, MSG_TSTAMP_*
* communicate network timestamps by passing this struct in a cmsg with
* recvmsg(). See Documentation/networking/timestamping.rst for details.
* User space sees a timespec definition that matches either
* __kernel_timespec or __kernel_old_timespec, in the kernel we
* require two structure definitions to provide both.
*/
struct scm_timestamping {
#ifdef __KERNEL__
struct __kernel_old_timespec ts[3];
#else
struct timespec ts[3];
#endif
};
struct scm_timestamping64 {
struct __kernel_timespec ts[3];
};
/* The type of scm_timestamping, passed in sock_extended_err ee_info.
* This defines the type of ts[0]. For SCM_TSTAMP_SND only, if ts[0]
* is zero, then this is a hardware timestamp and recorded in ts[2].
*/
enum {
SCM_TSTAMP_SND, /* driver passed skb to NIC, or HW */
SCM_TSTAMP_SCHED, /* data entered the packet scheduler */
SCM_TSTAMP_ACK, /* data acknowledged by peer */
};
#endif /* _UAPI_LINUX_ERRQUEUE_H */