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David Rheinsberg authored
This introduces a new generic SOL_SOCKET-level socket option called SO_BINDTOIFINDEX. It behaves similar to SO_BINDTODEVICE, but takes a network interface index as argument, rather than the network interface name. User-space often refers to network-interfaces via their index, but has to temporarily resolve it to a name for a call into SO_BINDTODEVICE. This might pose problems when the network-device is renamed asynchronously by other parts of the system. When this happens, the SO_BINDTODEVICE might either fail, or worse, it might bind to the wrong device. In most cases user-space only ever operates on devices which they either manage themselves, or otherwise have a guarantee that the device name will not change (e.g., devices that are UP cannot be renamed). However, particularly in libraries this guarantee is non-obvious and it would be nice if that race-condition would simply not exist. It would make it easier for those libraries to operate even in situations where the device-name might change under the hood. A real use-case that we recently hit is trying to start the network stack early in the initrd but make it survive into the real system. Existing distributions rename network-interfaces during the transition from initrd into the real system. This, obviously, cannot affect devices that are up and running (unless you also consider moving them between network-namespaces). However, the network manager now has to make sure its management engine for dormant devices will not run in parallel to these renames. Particularly, when you offload operations like DHCP into separate processes, these might setup their sockets early, and thus have to resolve the device-name possibly running into this race-condition. By avoiding a call to resolve the device-name, we no longer depend on the name and can run network setup of dormant devices in parallel to the transition off the initrd. The SO_BINDTOIFINDEX ioctl plugs this race. Reviewed-by:
Tom Gundersen <teg@jklm.no> Signed-off-by:
David Rheinsberg authoredThis introduces a new generic SOL_SOCKET-level socket option called SO_BINDTOIFINDEX. It behaves similar to SO_BINDTODEVICE, but takes a network interface index as argument, rather than the network interface name. User-space often refers to network-interfaces via their index, but has to temporarily resolve it to a name for a call into SO_BINDTODEVICE. This might pose problems when the network-device is renamed asynchronously by other parts of the system. When this happens, the SO_BINDTODEVICE might either fail, or worse, it might bind to the wrong device. In most cases user-space only ever operates on devices which they either manage themselves, or otherwise have a guarantee that the device name will not change (e.g., devices that are UP cannot be renamed). However, particularly in libraries this guarantee is non-obvious and it would be nice if that race-condition would simply not exist. It would make it easier for those libraries to operate even in situations where the device-name might change under the hood. A real use-case that we recently hit is trying to start the network stack early in the initrd but make it survive into the real system. Existing distributions rename network-interfaces during the transition from initrd into the real system. This, obviously, cannot affect devices that are up and running (unless you also consider moving them between network-namespaces). However, the network manager now has to make sure its management engine for dormant devices will not run in parallel to these renames. Particularly, when you offload operations like DHCP into separate processes, these might setup their sockets early, and thus have to resolve the device-name possibly running into this race-condition. By avoiding a call to resolve the device-name, we no longer depend on the name and can run network setup of dormant devices in parallel to the transition off the initrd. The SO_BINDTOIFINDEX ioctl plugs this race. Reviewed-by:
socket.h 2.41 KiB
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _ASM_IA64_SOCKET_H
#define _ASM_IA64_SOCKET_H
/*
* Socket related defines.
*
* Based on <asm-i386/socket.h>.
*
* Modified 1998-2000
* David Mosberger-Tang <davidm@hpl.hp.com>, Hewlett-Packard Co
*/
#include <asm/sockios.h>
/* For setsockopt(2) */
#define SOL_SOCKET 1
#define SO_DEBUG 1
#define SO_REUSEADDR 2
#define SO_TYPE 3
#define SO_ERROR 4
#define SO_DONTROUTE 5
#define SO_BROADCAST 6
#define SO_SNDBUF 7
#define SO_RCVBUF 8
#define SO_SNDBUFFORCE 32
#define SO_RCVBUFFORCE 33
#define SO_KEEPALIVE 9
#define SO_OOBINLINE 10
#define SO_NO_CHECK 11
#define SO_PRIORITY 12
#define SO_LINGER 13
#define SO_BSDCOMPAT 14
#define SO_REUSEPORT 15
#define SO_PASSCRED 16
#define SO_PEERCRED 17
#define SO_RCVLOWAT 18
#define SO_SNDLOWAT 19
#define SO_RCVTIMEO 20
#define SO_SNDTIMEO 21
/* Security levels - as per NRL IPv6 - don't actually do anything */
#define SO_SECURITY_AUTHENTICATION 22
#define SO_SECURITY_ENCRYPTION_TRANSPORT 23
#define SO_SECURITY_ENCRYPTION_NETWORK 24
#define SO_BINDTODEVICE 25
/* Socket filtering */
#define SO_ATTACH_FILTER 26
#define SO_DETACH_FILTER 27
#define SO_GET_FILTER SO_ATTACH_FILTER
#define SO_PEERNAME 28
#define SO_TIMESTAMP 29
#define SCM_TIMESTAMP SO_TIMESTAMP
#define SO_ACCEPTCONN 30
#define SO_PEERSEC 31
#define SO_PASSSEC 34
#define SO_TIMESTAMPNS 35
#define SCM_TIMESTAMPNS SO_TIMESTAMPNS
#define SO_MARK 36
#define SO_TIMESTAMPING 37
#define SCM_TIMESTAMPING SO_TIMESTAMPING
#define SO_PROTOCOL 38
#define SO_DOMAIN 39
#define SO_RXQ_OVFL 40
#define SO_WIFI_STATUS 41
#define SCM_WIFI_STATUS SO_WIFI_STATUS
#define SO_PEEK_OFF 42
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
#define SO_LOCK_FILTER 44
#define SO_SELECT_ERR_QUEUE 45
#define SO_BUSY_POLL 46
#define SO_MAX_PACING_RATE 47
#define SO_BPF_EXTENSIONS 48
#define SO_INCOMING_CPU 49
#define SO_ATTACH_BPF 50
#define SO_DETACH_BPF SO_DETACH_FILTER
#define SO_ATTACH_REUSEPORT_CBPF 51
#define SO_ATTACH_REUSEPORT_EBPF 52
#define SO_CNX_ADVICE 53
#define SCM_TIMESTAMPING_OPT_STATS 54
#define SO_MEMINFO 55
#define SO_INCOMING_NAPI_ID 56
#define SO_COOKIE 57
#define SCM_TIMESTAMPING_PKTINFO 58
#define SO_PEERGROUPS 59
#define SO_ZEROCOPY 60
#define SO_TXTIME 61
#define SCM_TXTIME SO_TXTIME
#define SO_BINDTOIFINDEX 62
#endif /* _ASM_IA64_SOCKET_H */