libpcap linux mmap patch

[Alexander 'Leo' Bergolth <leo () strike wu-wien ac at>]

Hi!

I just gave your new linux mmap patch a try, that was committed to svn
a few weeks ago.
The code works fine, except for two issues:

*) There is a typo in the macro RING_GET_FRAME(h) (handle instead of h).
The attached patch fixes that.

*) If pcap_loop is called with cnt=0 (ngrep erroneously does that), it
will busy-loop forever. pcap_read_linux_mmap doesn't handle that case,
it returns 0, which is asymmetric to pcap_read_linux's behavior, which
reads one packet. The second attached patch returns 0 directly in
pcap_loop(), if it is called with cnt=0.

Cheers,
--leo
-- 
e-mail   ::: Leo.Bergolth (at) wu-wien.ac.at
fax      ::: +43-1-31336-906050
location ::: Computer Center | Vienna University of Economics | Austria


--- pcap-linux.c.with_mmap      2008-01-31 09:44:49.310322964 +0100
+++ pcap-linux.c        2008-01-31 09:46:07.660101750 +0100
@@ -218,7 +218,7 @@
 static void pcap_close_linux(pcap_t *);
 
 #ifdef HAVE_PACKET_RING
-#define RING_GET_FRAME(h) (((struct tpacket_hdr**)h->buffer)[handle->offset])
+#define RING_GET_FRAME(h) (((struct tpacket_hdr**)h->buffer)[h->offset])
 
 static void destroy_ring(pcap_t *handle);
 static int create_ring(pcap_t* handle, unsigned size, char* errmsg);

--- pcap.c.orig 2008-01-31 10:22:53.997816397 +0100
+++ pcap.c      2008-01-31 10:21:00.463201991 +0100
@@ -92,6 +92,9 @@
 {
        register int n;
 
+       if (cnt == 0)
+         return (0);
+
        for (;;) {
                if (p->sf.rfile != NULL) {
                        /*

-
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