861e1061e05d9de6ab9d5876f3caf7ce7f21e62a
[openwrt/openwrt.git] / target / linux / generic / backport-4.19 / 095-Allow-class-e-address-assignment-via-ifconfig-ioctl.patch
1 From 46bf067870156abd61fe24d14c2486d15b8b502c Mon Sep 17 00:00:00 2001
2 From: Dave Taht <dave@taht.net>
3 Date: Fri, 14 Dec 2018 18:38:40 +0000
4 Subject: [PATCH 1/1] Allow class-e address assignment in ifconfig and early
5 boot
6
7 While the linux kernel became mostly "class-e clean" a decade ago,
8 and most distributions long ago switched to the iproute2 suite
9 of utilities, which allow class-e (240.0.0.0/4) address assignment,
10 distributions relying on busybox, toybox and other forms of
11 ifconfig cannot assign class-e addresses without this kernel patch.
12
13 With this patch, also, a boot command line on these addresses is feasible:
14 (ip=248.0.1.2::248.0.1.1:255.255.255.0).
15
16 While CIDR has been obsolete for 2 decades, and a survey of all the
17 userspace open source code in the world shows most IN_whatever macros
18 are also obsolete... rather than obsolete CIDR from this ioctl entirely,
19 this patch merely enables class-e assignment, sanely.
20
21 H/T to Vince Fuller and his original patch here:
22 https://lkml.org/lkml/2008/1/7/370
23
24 Signed-off-by: Dave Taht <dave.taht@gmail.com>
25 Reviewed-by: John Gilmore <gnu@toad.com>
26 ---
27 include/uapi/linux/in.h | 8 ++++++--
28 net/ipv4/devinet.c | 4 +++-
29 net/ipv4/ipconfig.c | 2 ++
30 3 files changed, 11 insertions(+), 3 deletions(-)
31
32 --- a/include/uapi/linux/in.h
33 +++ b/include/uapi/linux/in.h
34 @@ -268,8 +268,12 @@ struct sockaddr_in {
35 #define IN_MULTICAST(a) IN_CLASSD(a)
36 #define IN_MULTICAST_NET 0xF0000000
37
38 -#define IN_EXPERIMENTAL(a) ((((long int) (a)) & 0xf0000000) == 0xf0000000)
39 -#define IN_BADCLASS(a) IN_EXPERIMENTAL((a))
40 +#define IN_BADCLASS(a) ((((long int) (a) ) == 0xffffffff)
41 +#define IN_EXPERIMENTAL(a) IN_BADCLASS((a))
42 +
43 +#define IN_CLASSE(a) ((((long int) (a)) & 0xf0000000) == 0xf0000000)
44 +#define IN_CLASSE_NET 0xffffffff
45 +#define IN_CLASSE_NSHIFT 0
46
47 /* Address to accept any incoming messages. */
48 #define INADDR_ANY ((unsigned long int) 0x00000000)
49 --- a/net/ipv4/devinet.c
50 +++ b/net/ipv4/devinet.c
51 @@ -941,7 +941,7 @@ static int inet_abc_len(__be32 addr)
52 {
53 int rc = -1; /* Something else, probably a multicast. */
54
55 - if (ipv4_is_zeronet(addr))
56 + if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
57 rc = 0;
58 else {
59 __u32 haddr = ntohl(addr);
60 @@ -952,6 +952,8 @@ static int inet_abc_len(__be32 addr)
61 rc = 16;
62 else if (IN_CLASSC(haddr))
63 rc = 24;
64 + else if (IN_CLASSE(haddr))
65 + rc = 32;
66 }
67
68 return rc;
69 --- a/net/ipv4/ipconfig.c
70 +++ b/net/ipv4/ipconfig.c
71 @@ -429,6 +429,8 @@ static int __init ic_defaults(void)
72 ic_netmask = htonl(IN_CLASSB_NET);
73 else if (IN_CLASSC(ntohl(ic_myaddr)))
74 ic_netmask = htonl(IN_CLASSC_NET);
75 + else if (IN_CLASSE(ntohl(ic_myaddr)))
76 + ic_netmask = htonl(IN_CLASSE_NET);
77 else {
78 pr_err("IP-Config: Unable to guess netmask for address %pI4\n",
79 &ic_myaddr);