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authorWillem de Bruijn <willemb@google.com>2020-07-10 16:29:02 +0300
committerDavid S. Miller <davem@davemloft.net>2020-07-20 05:20:22 +0300
commiteba75c587e811d3249c8bd50d22bb2266ccd3c0f (patch)
tree28fe5ba40b6a9b252fa8c7e3861922c4aaaad0f3 /include/uapi/linux/errqueue.h
parent930bc4cc359bdf94029ecb867811000dd87a2c3d (diff)
downloadlinux-eba75c587e811d3249c8bd50d22bb2266ccd3c0f.tar.xz
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>
Diffstat (limited to 'include/uapi/linux/errqueue.h')
-rw-r--r--include/uapi/linux/errqueue.h14
1 files changed, 13 insertions, 1 deletions
diff --git a/include/uapi/linux/errqueue.h b/include/uapi/linux/errqueue.h
index ca5cb3e3c6df..3c70e8ac14b8 100644
--- a/include/uapi/linux/errqueue.h
+++ b/include/uapi/linux/errqueue.h
@@ -5,6 +5,13 @@
#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;
@@ -12,7 +19,10 @@ struct sock_extended_err {
__u8 ee_code;
__u8 ee_pad;
__u32 ee_info;
- __u32 ee_data;
+ union {
+ __u32 ee_data;
+ struct sock_ee_data_rfc4884 ee_rfc4884;
+ };
};
#define SO_EE_ORIGIN_NONE 0
@@ -31,6 +41,8 @@ struct sock_extended_err {
#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
*