Re: [PATCH] netdevice.7: Update documentation for SIOCGIFADDR SIOCSIFADDR SIOCDIFADDR
From: Alejandro Colomar (man-pages) <hidden>
Date: 2021-01-02 18:04:59
Hi Pali, Please, see some comments below. On 1/2/21 3:02 PM, Pali Rohár wrote:
quoted hunk ↗ jump to hunk
Also add description for struct in6_ifreq which is used for IPv6 addresses. SIOCSIFADDR and SIOCDIFADDR can be used to add or delete IPv6 address and pppd is using these ioctls for a long time. Surprisingly SIOCDIFADDR cannot be used for deleting IPv4 address but only for IPv6 addresses. Signed-off-by: Pali Rohár <pali@kernel.org> --- man7/netdevice.7 | 36 +++++++++++++++++++++++++++++------- 1 file changed, 29 insertions(+), 7 deletions(-)diff --git a/man7/netdevice.7 b/man7/netdevice.7 index 488e83d9a..5b68e4988 100644 --- a/man7/netdevice.7 +++ b/man7/netdevice.7@@ -55,9 +55,27 @@ struct ifreq { .EE .in .PP +Exception is +.B AF_INET6 +socket for which is used +.I in6_ifreq +structure:
Wording fix: [ AF_INET6 is an exception. It passes an .I in6_ifreq structure: ] Are there more exceptions? Or is it the only one?
+.PP
+.in +4n
+.EX
+struct in6_ifreq {
+ struct in6_addr ifr6_addr;
+ u32 ifr6_prefixlen;
+ int ifr6_ifindex; /* Interface index */
+};
+.EE
+.in
+.PP
Normally, the user specifies which device to affect by setting
.I ifr_name
-to the name of the interface.
+to the name of the interface or
+.I ifr6_ifindex
+to the index of the interface.I've seen there's ifr_ifindex too (see SIOCGIFNAME). Can it be used in the same way as ifr6_ifindex?
quoted hunk ↗ jump to hunk
All other members of the structure may share memory. .SS Ioctls@@ -142,13 +160,17 @@ IFF_ISATAP:Interface is RFC4214 ISATAP interface. .PP Setting the extended (private) interface flags is a privileged operation. .TP -.BR SIOCGIFADDR ", " SIOCSIFADDR -Get or set the address of the device using -.IR ifr_addr . -Setting the interface address is a privileged operation. -For compatibility, only +.BR SIOCGIFADDR ", " SIOCSIFADDR ", " SIOCDIFADDR +Get, set or delete the address of the device using +.IR ifr_addr " or " ifr6_addr " with " ifr6_prefixlen .
Generally, we place each name on a single line. The line after .TP is an exception, as you can see above. So this would be: [ .IR ifr_addr , or .I ifr6_addr with .IR ifr6_prefixlen . ]
+Setting or deleting the interface address is a privileged operation. +For compatibility, +.BR SIOCGIFADDR " returns only " AF_INET " addresses, " +.BR SIOCSIFADDR " accepts " AF_INET " and " AF_INET6 " addresses and " +.BR SIOCDIFADDR " deletes only " AF_INET6 " addresses. "
See above.
.B AF_INET -addresses are accepted or returned. +address can be deleted by setting zero address via +.BR SIOCSIFADDR . .TP .BR SIOCGIFDSTADDR ", " SIOCSIFDSTADDR Get or set the destination address of a point-to-point device using
Thanks, Alex -- Alejandro Colomar Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/ http://www.alejandro-colomar.es/