Hi Linus,
This tiny patch extends ipchains logging. This way one can distinguish
(plain) connection attempts and (Xmas, Fin,...) scans. E.g.
kernel: Packet log: input - lo PROTO=6 127.0.0.1:40326 127.0.0.1:80
L=40 S=0x00 I=5808 F=0x0000 T=51 (#1)
vs.
L=40 S=0x00 I=5808 F=0x0000 T=51 (#1) B=-s--a-
and
L=40 S=0x00 I=5808 F=0x0000 T=51 (#1) B=fs-p-u
Please comment on the format (B=...) and implementation details (speed).
The patch is against 2.2.17's /net/ipv4/ip_fw.c
ipchains log with flags Christian W. Zuckschwerdt <[EMAIL PROTECTED]>
--- linux-2.2.17-pristine/net/ipv4/ip_fw.c.orig Mon Nov 27 00:38:36 2000
+++ linux-2.2.17/net/ipv4/ip_fw.c Sun Dec 3 23:58:06 2000
@@ -415,6 +415,7 @@
{
__u32 *opt = (__u32 *) (ip + 1);
int opti;
+ struct tcphdr *tcp=(struct tcphdr *)((__u32 *)ip+ip->ihl);
if (f)
{
@@ -443,7 +444,15 @@
for (opti = 0; opti < (ip->ihl - sizeof(struct iphdr) / 4); opti++)
printk(" O=0x%8.8X", *opt++);
- printk(" %s(#%d)\n", syn ? "SYN " : /* "PENANCE" */ "", count);
+ printk(" %s(#%d)", syn ? "SYN " : /* "PENANCE" */ "", count);
+
+ if (ip->protocol == IPPROTO_TCP)
+ printk(" B=%c%c%c%c%c%c\n", tcp->fin ? 'f' : '-',
+ tcp-syn ? 's' : '-', tcp->rst ? 'r' : '-',
+ tcp->psh ? 'p' : '-', tcp->ack ? 'a' : '-',
+ tcp->urg ? 'u' : '-');
+ else
+ printk("\n");
}
/* function for checking chain labels for user space. */
--
cu.
:
Christian
-
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