OK. I've written some code based on Trevor Hamm's suggestions, but it
segfaults. Here's what I have:
----- BEGIN CODE -----
struct in_device *in_dev;
struct in_ifaddr **ifap = NULL;
struct in_ifaddr *ifa = NULL;
struct net_device *dev;
struct in_addr in;
unsigned long pci_ip_dword;
char iname[4];
strcpy(iname, "eth0");
if ( (dev = dev_get_by_name(iname)) == NULL ) {
printk(" |--> Couldn't find a network interface.\n");
printk(" You need at least one interface (eth0) for this
netfilter hook to work.\n");
return 0;
}
printk("Looking for 'eth0' . . .\n");
if ( (in_dev = in_dev_get(dev)) != NULL ) {
if (ifa == NULL) {
for (ifap=&in_dev->ifa_list; (ifa=*ifap) != NULL;
ifap=&ifa->ifa_next)
if (strcmp(iname, ifa->ifa_label) == 0)
break;
}
}
printk("making dword . . .\n");
in.s_addr = ifa->ifa_local;
pci_ip_dword = (unsigned long)in.s_addr;
pci_ip_dword = (pci_ip_dword << 15);
pci_ip_dword = (pci_ip_dword & 0x7F800000);
printk("My IP address dword is: %lx\n", (unsigned long)pci_ip_dword);
----- END CODE -----
When I modprobe my netfilter target, dmesg has this in it:
----- BEGIN DMESG DUMP -----
Looking for 'eth0' . . .
making dword . . .
My IP address dword is: 54000000
making a note of it . . .
Unable to handle kernel NULL pointer dereference at virtual address
00000011
printing eip:
e0840a02
*pde = 00000000
Oops: 0002
CPU: 0
EIP: 0010:[<e0840a02>] Not tainted
EFLAGS: 00010286
eax: 00000001 ebx: e08480b0 ecx: 30687465 edx: 00000001
esi: 00000070 edi: e0848040 ebp: 00000000 esp: def73d74
ds: 0018 es: 0018 ss: 0018
Process iptables (pid: 102, stackpage=def73000)
Stack: def73e08 e0848040 e08480d0 00000000 00000002 00000000 00000163
e084a040
00000000 def73dc0 e084b000 c0126c4f def73dc0 00000000 e084833c
e0848040
00000000 0004b000 00000000 00000000 e0841149 def73e08 0000000e
e0848000
Call Trace: [<c0126c4f>] [<e0841149>] [<e084161b>] [<e0842880>]
[<c01bf540>]
[<c01bf5a2>] [<c01cabef>] [<c010ff03>] [<c01e0318>] [<c01e5c7a>]
[<c01b42f1>]
[<c01b4996>] [<c0106c5b>]
Code: ff 40 10 8b 42 34 80 48 14 18 89 53 04 b9 80 27 84 e0 ff 05
----- END DMESG DUMP -----
The pci_ip_dword isn't correct either. Grrrr. Kernel hacking. Grrrr.
-Jeremy
--
----------------------------
Jeremy C. Andrus
http://www.jeremya.com/
----------------------------
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