clarify error message

loop until buffer size is acceptable
BIOCIMMEDIATE: set if exists

based on patches from Darren Reed <[email protected]>

diff --git a/pcap-bpf.c b/pcap-bpf.c
index b1162f77015e71173121cd3c4c408d5366294da6..8c11b51db118114f66caf6601efb13f67af0773e 100644 (file)
--- a/pcap-bpf.c
+++ b/pcap-bpf.c
@@ -20,7 +20,7 @@
  */
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.33 2000-04-27 09:11:12 itojun Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.34 2000-07-10 04:50:05 assar Exp $ (LBL)";
 #endif
 
 #include <sys/param.h>                 /* optionally get BSD define */
@@ -152,7 +152,7 @@ bpf_open(pcap_t *p, char *errbuf)
         * XXX better message for all minors used
         */
        if (fd < 0)
-               snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s",
+               snprintf(errbuf, PCAP_ERRBUF_SIZE, "(no devices found) %s: %s",
                    device, pcap_strerror(errno));
 
        return (fd);
@@ -193,11 +193,20 @@ pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
                goto bad;
        }
        v = 32768;      /* XXX this should be a user-accessible hook */
-       /* Ignore the return value - this is because the call fails on
-        * BPF systems that don't have kernel malloc.  And if the call
-        * fails, it's no big deal, we just continue to use the standard
-        * buffer size.
-        */
+       /* try finding a good size for the buffer */
+       do {
+               (void) ioctl(fd, BIOCSBLEN, (caddr_t)&v);
+ 
+               (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
+               if ((ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) &&
+                   (errno != ENOBUFS)) {
+                       snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s",
+                           errno, device, pcap_strerror(errno));
+                       goto bad;
+               }
+               v >>= 2;
+       } while (fd < 0 && errno == ENOBUFS);
+
        (void) ioctl(fd, BIOCSBLEN, (caddr_t)&v);
 
        (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
@@ -253,6 +262,16 @@ pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
                        goto bad;
                }
        }
+
+#ifdef BIOCIMMEDIATE
+       v = 1;
+       if (ioctl(p->fd, BIOCIMMEDIATE, &v) < 0) {
+               snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCIMMEDIATE: %s",
+                   pcap_strerror(errno));
+               goto bad;
+       }
+#endif /* BIOCIMMEDIATE */
+
        if (promisc)
                /* set promiscuous mode, okay if it fails */
                (void)ioctl(p->fd, BIOCPROMISC, NULL);