Commit 65cab850 authored by Dave Taht's avatar Dave Taht Committed by David S. Miller
Browse files

net: Allow class-e address assignment via ifconfig ioctl 



While most distributions long ago switched to the iproute2 suite
of utilities, which allow class-e (240.0.0.0/4) address assignment,
distributions relying on busybox, toybox and other forms of
ifconfig cannot assign class-e addresses without this kernel patch.

While CIDR has been obsolete for 2 decades, and a survey of all the
open source code in the world shows the IN_whatever macros are also
obsolete... rather than obsolete CIDR from this ioctl entirely, this
patch merely enables class-e assignment, sanely.

Signed-off-by: default avatarDave Taht <dave.taht@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 69d2c867

include/uapi/linux/in.h

+7 −3
Original line number Diff line number Diff line
@@ -266,10 +266,14 @@ struct sockaddr_in { 


#define	IN_CLASSD(a)		((((long int) (a)) & 0xf0000000) == 0xe0000000)

#define	IN_MULTICAST(a)		IN_CLASSD(a)

#define IN_MULTICAST_NET	0xF0000000

#define	IN_MULTICAST_NET	0xe0000000



#define	IN_EXPERIMENTAL(a)	((((long int) (a)) & 0xf0000000) == 0xf0000000)

#define	IN_BADCLASS(a)		IN_EXPERIMENTAL((a))

#define	IN_BADCLASS(a)		((((long int) (a) ) == 0xffffffff)

#define	IN_EXPERIMENTAL(a)	IN_BADCLASS((a))



#define	IN_CLASSE(a)		((((long int) (a)) & 0xf0000000) == 0xf0000000)

#define	IN_CLASSE_NET		0xffffffff

#define	IN_CLASSE_NSHIFT	0



/* Address to accept any incoming messages. */

#define	INADDR_ANY		((unsigned long int) 0x00000000)

net/ipv4/devinet.c

+3 −2
Original line number Diff line number Diff line
@@ -952,17 +952,18 @@ static int inet_abc_len(__be32 addr) 
{

	int rc = -1;	/* Something else, probably a multicast. */



	if (ipv4_is_zeronet(addr))

	if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))

		rc = 0;

	else {

		__u32 haddr = ntohl(addr);



		if (IN_CLASSA(haddr))

			rc = 8;

		else if (IN_CLASSB(haddr))

			rc = 16;

		else if (IN_CLASSC(haddr))

			rc = 24;

		else if (IN_CLASSE(haddr))

			rc = 32;

	}



	return rc;

net/ipv4/ipconfig.c

+2 −0
Original line number Diff line number Diff line
@@ -429,6 +429,8 @@ static int __init ic_defaults(void) 
			ic_netmask = htonl(IN_CLASSB_NET);

		else if (IN_CLASSC(ntohl(ic_myaddr)))

			ic_netmask = htonl(IN_CLASSC_NET);

		else if (IN_CLASSE(ntohl(ic_myaddr)))

			ic_netmask = htonl(IN_CLASSE_NET);

		else {

			pr_err("IP-Config: Unable to guess netmask for address %pI4\n",

			       &ic_myaddr);

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